CN104136715A - Method and system for managing clearances in a piston engine - Google Patents

Abstract

A piston engine may include a heat pipe configured to transfer heat outward from a portion of the piston engine, such as a combustion section. The heating tube may be included as part of the piston assembly, the cylinder, or both. The heating tube may be filled with a suitable heating tube fluid capable of undergoing a phase change, such as water, ethanol, ammonia, sodium, other fluids, or combinations thereof. Boiling and condensing of the fluid in the heating tube may utilize the latent heat of the fluid during heat transfer. In some cases multiple heating tubes may be used.

Description

Method and system for managing clearances in a piston engine

Background technique

As the compression ratio of an engine increases, the surface-to-volume ratio (surface-to-volume ratio) at top dead center (TDC) increases, temperature increases and pressure increases while maintaining a specific bore-to-stroke ratio. high. This has three main consequences: 1) increased heat transfer from the combustion chamber, 2) combustion phasing becomes difficult, and 3) increased friction and mechanical losses. Heat transfer increases because the thermal boundary layer becomes a larger portion of the total volume as the aspect ratio at TDC (ie, the ratio of cylinder bore diameter to length of the combustion chamber) becomes smaller. Both combustion phasing and achieving complete combustion present challenges due to the small volume achieved at TDC. An increase in combustion chamber pressure translates directly into increased forces acting on engine components. These high forces can overload mechanical connections (eg, piston pins, piston rods, crankshaft) and compressed self-tightening seal rings in the engine, thereby causing increased friction, wear, and/or failure.

A major challenge associated with linear piston engines is to efficiently convert the kinetic energy of the pistons into mechanical work and/or electrical energy. The space between the piston and cylinder wall (referred to herein as "clearance") is necessary to maintain piston alignment, avoid piston and cylinder wall contact and associated frictional losses, and control gas leakage past the piston (e.g., blowby gas). The key. Clearance may be affected by unbalanced forces acting on the piston, thermally induced expansion or contraction (eg solid deformation), changing engine conditions, or other related factors. Management of clearances, piston temperature, cylinder temperature, or a combination thereof may be desirable in certain applications.

Contents of the invention

In certain embodiments, a piston engine may include a piston and cylinder assembly that may include a fluid bearing in a gap between a bore of the cylinder and the piston assembly. The piston assembly is axially translatable within the cylinder bore, and the cylinder-facing end of the piston face may contact the combustion section of the cylinder. At least one bearing element may provide bearing fluid flow into a gap between the cylinder barrel and the piston assembly to form a fluid bearing. In some embodiments, the bearing element may be part of a piston assembly providing radially outward flow of bearing fluid, and the piston assembly may include fluid channels for directing the bearing fluid. In some embodiments, the bearing element may be part of a cylinder providing radially inward flow of bearing fluid, and the cylinder may include fluid channels for directing the bearing fluid. The bearing element may include holes, jetting surfaces, any other suitable fluid outlet or any combination thereof for providing bearing fluid to the gap.

In certain embodiments, a piston engine may include a piston and cylinder assembly including a piston and cylinder having self-centering features. The piston may be configured to translate axially within the cylinder bore of the cylinder.

In some embodiments, the piston may be part of a piston assembly that translates axially within the cylinder bore of the cylinder. A cylinder may include a combustion section capable of containing combustion products. Blowby gases from the combustion section can flow axially from the combustion section, past the piston face, and through the gap between the piston and the cylinder. The self-centering feature may utilize the flow of blowby gas to provide a self-centering force on the piston. The self-centering feature may be a step, one or more slotted notches, a taper, any other suitable feature, or any combination thereof.

In some embodiments, a piston engine may include a piston assembly having one or more heated tubes. The piston assembly may be configured to translate axially within the cylinder bore of the cylinder. The cylinder may include a combustion section that can contain combustion products, and accordingly the piston face of the piston assembly may experience an increase in temperature. In some embodiments, the heating tube may be in thermal contact with the piston face and also be capable of transferring heat from the piston face to the heat reservoir. A first portion of the heating tube can receive heat from the piston face, and a second portion of the heating tube can transfer heat to the heat reservoir. The heating tube may comprise a fluid such as water, ethanol, ammonia or sodium which may undergo a gas-liquid phase transition.

In certain embodiments, a piston engine may include a cylinder liner configured to be coaxially positioned within a cylinder of the piston engine. The cylinder liner may include an inner surface configured to form a clearance with a piston assembly axially translatable within the cylinder liner. The cylinder liner may also include an outer surface that interfaces with the cylinder of the piston engine. The interface between the outer surface and the cylinder may include a fluid channel that may serve as a conduit for a pressure controlled fluid. The cylinder liner may be configured to radially contract or expand based at least in part on the pressure-controlled fluid, and thereby the clearance may be adjusted.

In certain embodiments, a piston engine may include one or more fluid passages configured to provide localized, selective, fast-response, or otherwise controlled heating or cooling of the cylinders. The flow rate, temperature, pressure or combination thereof provided to the fluid passages may be adjusted by the control system to control the temperature of the piston engine. In certain embodiments, the cylinder may include one or more localized heat sources such as one or more electric heaters that may be controlled by the control system to provide localized heating.

In certain embodiments, the clearance between a coaxial piston assembly and a cylinder in a piston engine may be controlled. One or more sensors may be utilized to detect at least one indicator such as temperature, pressure, work interaction, and/or other suitable indicators of clearance. The control response may be determined by the processing device based at least in part on the indicator. The processing device may use the control interface to provide a control signal to at least one auxiliary system of the piston engine based at least in part on the control response. At least one auxiliary system may adjust the gap based at least in part on the control signal.

Description of drawings

The above and other features of the present disclosure, its substance and various advantages will become more apparent upon consideration of the following detailed description when taken in conjunction with the accompanying drawings, in which:

1 shows a cross-sectional view of an exemplary piston engine having a piston assembly, gas springs, and integrated linear electromagnetic machine (LEM) included as part of the cylinder, according to certain embodiments of the present disclosure. );

2 illustrates a cross-sectional view of an exemplary piston engine having a piston assembly, gas springs, and integrated linear electromagnetic machine (LEM), according to certain embodiments of the present disclosure;

3 illustrates a cross-sectional view of an exemplary piston engine having a piston assembly including two pistons, a separate gas spring, and an integrated LEM, according to certain embodiments of the present disclosure;

4 illustrates a cross-sectional view of an exemplary piston engine having two piston assemblies, separate gas springs, and two integrated LEMs, according to certain embodiments of the present disclosure;

5 illustrates a perspective view of a portion of an exemplary piston assembly having a self-centering feature, according to certain embodiments of the present disclosure;

6 illustrates a cross-sectional view of an exemplary piston assembly and cylinder with blow-by gas from the combustion section, according to certain embodiments of the present disclosure;

7 illustrates a cross-sectional view of the exemplary piston assembly and cylinder of FIG. 6, wherein the piston assembly is eccentric, according to certain embodiments of the present disclosure;

8 illustrates a cross-sectional view of the exemplary piston assembly and cylinder of FIG. 6 with the piston assembly centered, according to certain embodiments of the present disclosure;

9 illustrates a cross-sectional view of a portion of an exemplary piston engine having a piston assembly with features that may assist in its centering, according to certain embodiments of the present disclosure;

10 illustrates a cross-sectional view of a portion of an exemplary piston engine having a piston assembly having a notched self-centering feature, according to certain embodiments of the present disclosure;

11 illustrates a cross-sectional view of a portion of an exemplary piston engine having a piston assembly having a stepped self-centering feature, according to certain embodiments of the present disclosure;

12 illustrates a cross-sectional view of a portion of an exemplary piston engine having a tapered self-centering feature of a piston assembly, according to certain embodiments of the present disclosure;

13 illustrates a perspective view of a portion of an exemplary piston assembly with a bearing element having a bore, according to certain embodiments of the present disclosure;

14 illustrates a perspective view of a portion of an exemplary piston assembly having a porous bearing element, according to certain embodiments of the present disclosure;

15 illustrates a cross-sectional view of an exemplary piston assembly with a fluid bearing extending through the piston assembly, according to certain embodiments of the present disclosure;

16 illustrates a cross-sectional view of an exemplary piston assembly and cylinder with a fluid bearing extending through the piston assembly, according to certain embodiments of the present disclosure;

17 illustrates a cross-sectional view of an exemplary piston assembly and cylinder with a fluid bearing extending through the cylinder, according to certain embodiments of the present disclosure;

18 shows a cross-sectional view of an exemplary arrangement of a piston assembly and cylinder with a fluid bearing and a translator including a fluid passage, according to certain embodiments of the present disclosure;

Figure 19 shows a cross-sectional view of an exemplary arrangement of a piston assembly and cylinder with fluid bearings and check valves, according to certain embodiments of the present disclosure;

Figure 20 shows a cross-sectional view of an exemplary piston assembly and cylinder in which a heater tube is included as part of the piston assembly, according to certain embodiments of the present disclosure;

Figure 21 shows a cross-sectional view of an exemplary piston assembly in which a heated tube is formed by a void inside, according to certain embodiments of the present disclosure;

22 illustrates a cross-sectional view of an exemplary piston engine including a piston assembly and a cylinder with coolant passages and heating tubes, according to certain embodiments of the present disclosure;

23 illustrates a cross-sectional view of an exemplary piston assembly and cylinder with a deformable cylinder liner, according to certain embodiments of the present disclosure;

24 illustrates a cross-sectional view of the exemplary piston assembly and cylinder of FIG. 23 with the deformable cylinder liner undergoing deformation, according to certain embodiments of the present disclosure;

25 illustrates a cross-sectional view of an exemplary piston assembly and cylinder with a segmented deformable cylinder liner, according to certain embodiments of the present disclosure;

26 illustrates a cross-sectional view of an exemplary piston engine having a deformable cylinder liner, according to certain embodiments of the present disclosure;

27 illustrates a cross-sectional view of a portion of an exemplary piston engine with localized coolant passages, according to certain embodiments of the present disclosure;

28 illustrates a cross-sectional view of a portion of an exemplary piston engine with localized coolant passages, according to certain embodiments of the present disclosure;

29 illustrates a cross-sectional view of a portion of an exemplary piston engine with a localized heat source including an electric heater, according to certain embodiments of the present disclosure;

Figure 30 illustrates a cross-sectional view of a portion of an exemplary piston engine including fluid passages that may be used for heating, cooling, or both, according to certain embodiments of the present disclosure;

31 illustrates a perspective view of a portion of an exemplary piston assembly with bearing elements and self-centering features, according to certain embodiments of the present disclosure;

32 illustrates a cross-sectional view of an exemplary piston engine with a piston assembly having bearing elements, heated tubes, and self-centering features, and a cylinder with deformable cylinder liners and coolant passages, according to certain embodiments of the present disclosure ;

33 is a block diagram of an exemplary control arrangement for a piston engine according to certain embodiments of the present disclosure;

34 is a flowchart of exemplary steps for adjusting clearances of a piston engine according to certain embodiments of the present disclosure; and

35 is a flowchart of exemplary steps for adjusting one or more properties of a piston engine according to certain embodiments of the present disclosure.

Detailed ways

The present disclosure relates to managing clearances and/or other properties of piston engines. Although discussed in the context of a free-piston engine, the techniques and devices disclosed herein can be applied to non-free-piston engines or other suitable mechanical systems. Herein the term "piston engine" shall mean both free-piston and non-free-piston engines.

A piston engine operating using any suitable thermodynamic cycle may include a piston and cylinder assembly for effecting displacement work. The piston and cylinder can be separated by a relatively small gap, and the piston translates axially within the cylinder's bore. In some embodiments, the piston may be included as part of a "piston assembly," which may also include one or more piston seals (such as piston rings), bearing elements, frames, piston rods, translators, and/or Other components, which are able to move collectively as a substantially rigid assembly at least partially within the cylinder. The clearance may be constant or variable (eg, the clearance may be described by a thickness value, a value curve or range, and/or a measure of symmetry) along the radial circumference of the piston assembly or component thereof. The cylinder may include a combustion section into which an oxidant (eg, air, dirty air, oxygen) and fuel (eg, gaseous or liquid hydrocarbon fuel) may be fed, either separately or as a premixed mixture. The expansion of the high temperature combustion products causes the displacement of the piston. Mechanical connections (e.g., using a piston rod and crankshaft assembly), electromagnetic interactions (e.g., using a linear electromagnetic machine (LEM) with a translator and a stator as described in this disclosure), pneumatic connections (e.g., using two pistons interacting with a gas volume in between), any other suitable work-making technique, or any combination thereof to perform work by the motion of the pistons. Compression of air and/or fuel by the piston-cylinder assembly may also be accomplished using the movement of the piston. In some embodiments, the work of compression may be provided by a gas driven device, a LEM, or both.

1-4 illustrate a piston engine that may benefit from the teachings of the present disclosure. It should be understood that the teachings of the present disclosure may be applied to any other suitable piston engine in addition to that shown in the drawings and described herein. It should also be understood that although not shown in FIGS. 1-4 , a piston engine may include one or more subsystems such as a cooling subsystem, air delivery system, fuel delivery system, ignition subsystem, exhaust system, Electronic control systems and/or other suitable subsystems, and the term "piston engine" may denote a collection of suitable components and subsystems.

1 illustrates a cross-sectional view of an exemplary piston engine 100 having a piston assembly 110, a gas spring 148, and an integrated linear electromagnetic machine (LEM) 160, according to certain embodiments of the present disclosure. Piston engine 100 includes cylinder 140 having cylinder bore 134 and combustion section 130 , and piston assembly 110 . In the illustrated embodiment, piston assembly 110 includes two piston faces 112 , piston seals 114 and 115 , and translator 116 . Although not shown in FIG. 1 , piston assembly 110 may include a bearing element, a piston rod, any other suitable component, or any combination thereof. In the illustrated embodiment, piston assembly 110 is positioned entirely within bore 134 of cylinder 140 and is configured to translate substantially along axis 150 . As shown in FIG. 1 , cylinder 140 includes exhaust/injection port 170 (for exhaust gas and/or injection of reactants), intake port 180 (for input of air and/or air/fuel mixture), and drive gas port 190 (for supplying and/or exhausting drive gas). Piston engine 100 may operate using a two-stroke cycle, a four-stroke cycle, any other suitable cycle, or any combination thereof. An impingement plate 108 may be included in certain embodiments to help resist impact, for example, during combustion. Valves and/or other fluid components may, but are not required, be used in any or all of ports 170 , 180 , and 190 to control the flow of fluid into and out of piston engine 100 .

Cylinder 140 may include subsection 132 in which combustion, gas expansion and exhaust can take place, section 168 in which electromagnetic work interaction can take place, and section 178 in which gas drive and gas spring action can take place. The various sections 132 , 168 , and 178 may depend on the configuration of the cylinder 140 and the position of the piston assembly 110 within the bore 134 of the cylinder 140 . As shown in FIG. 1 , a stator 162 for performing electromagnetic work by movement of the translator 116 may be included as part of the cylinder 140 .

Translator 116 may translate across stator 162 during an expansion stroke of piston assembly 110 within cylinder 140 due to combustion of oxidant and fuel in combustion section 130 . Movement of the translator 116 relative to the stator 162 may generate an electrical current and correspond to electrical work. LEM 160 may comprise a permanent magnet motor, an induction motor, a switched reluctance motor, any other suitable electromagnetic machine, or any combination thereof. For example, translator 116 may include a permanent magnet, and stator 162 may include a coil that may conduct an induced current generated by movement of translator 116 .

FIG. 2 illustrates a cross-sectional view of an exemplary piston engine 200 having a piston assembly 210 , gas spring 248 and LEM 260 , according to certain embodiments of the present disclosure. Piston engine 200 includes cylinder 240 having cylinder bore 234 , piston assembly 210 and combustion section 230 . In the illustrated embodiment, the piston assembly 210 includes a piston face 212 , a piston seal 214 (eg, piston ring, sealing face), a translator 216 , and a piston rod 218 . Although not shown in FIG. 2 , piston assembly 210 may include bearing elements, any other suitable components, or any combination thereof. In the illustrated embodiment, piston assembly 210 is positioned partially within bore 234 of cylinder 240 and is configured to translate substantially along axis 250 . As shown in FIG. 2, the cylinder 240 includes a gas seal 242 (for reducing or avoiding gas leakage while allowing relative piston movement), an exhaust/injection port 270 (for exhaust gas and/or injection of reactants), an intake air Port 280 (for input of air and/or air/fuel mixture) and actuation gas port 290 (for supply and/or exhaust of actuation gas). Piston engine 200 may operate using a two-stroke cycle, a four-stroke cycle, any other suitable cycle, or any combination thereof. An impingement plate 208 may be included in some embodiments.

Cylinder 240 may include portion 232 in which combustion, gas expansion and exhaust can take place and portion 278 in which gas drive and gas spring can function. Portion 268 may be included independently of cylinder 240 and may include LEM 260 that can be used for electromagnetic work interaction. The various sections 232 , 268 , and 278 may depend on the configuration of the cylinder 240 and the position of the piston assembly 210 within the bore 234 of the cylinder 240 . As shown in FIG. 2 , the stator 262 for performing electromagnetic work by the movement of the translator 216 may, but need not, be independent of the cylinder 240 .

3 illustrates a cross-sectional view of an exemplary piston engine 300 having a piston assembly 310 including two pistons 311 and 313 , a single gas spring 340 and a LEM 360 , according to certain embodiments of the present disclosure. Piston engine 300 includes cylinders 340 and 341 having cylinder bores 334 and 335 respectively, a piston assembly 310 and a combustion section 330 . In the illustrated embodiment, piston assembly 310 includes piston face 312 , translator 316 , piston seals 314 and 315 , and piston rod 318 . Although not shown in FIG. 3 , piston assembly 310 may include bearing elements, any other suitable components, or any combination thereof. In the illustrated embodiment, piston assembly 310 is positioned partially within bore 334 of cylinder 340 and partially within bore 335 of cylinder 341 , and is configured to translate substantially along axis 350 . As shown in FIG. 3, the cylinder 340 includes a gas seal 342 (for reducing or avoiding gas leakage while allowing relative piston movement), an exhaust/injection port 370 (for exhaust and/or injection of reactants), an intake air Port 380 (for input of air and/or air/fuel mixture) and gas port 395 (for exhaust of blowby gas or supply of air). As shown in FIG. 3 , cylinder 341 includes gas seal 343 (for reducing or avoiding gas leakage while allowing relative piston movement), drive gas port 390 (for supplying and/or exhausting drive gas). Piston engine 300 may operate using a two-stroke cycle, a four-stroke cycle, any other suitable cycle, or any combination thereof. An impingement plate 308 may be included in some embodiments.

Cylinder 340 may include portion 332 in which combustion, gas expansion, and exhaust can occur. The air cylinder 341 may include a portion 378 in which the gas drive and gas spring can function. Section 368 may be included between cylinders 340 and 341 and may include a LEM that can be used for electromagnetic work interaction. Each section 332 , 368 , and 378 may depend on the configuration of the cylinders 340 and 341 and the position of the piston assembly 310 within the bores 334 and 335 of the respective cylinders 340 and 341 . As shown in FIG. 3 , the stator 362 for performing electromagnetic work by the movement of the translator 316 may, but need not, be independent of the cylinders 340 and 341 .

4 shows a cross-sectional view of an exemplary piston engine 400 having two piston assemblies 410 and 411, individual gas springs 448 and 449, and two LEMs 460 and 449, according to certain embodiments of the present disclosure. 461. As shown, piston engine 400 is substantially equivalent to two piston engines 300 having a single combustion chamber, symmetrical about exhaust/injection port 370 . It should be understood that other, possibly but not necessarily symmetrical, dual-piston arrangements can also be implemented in accordance with the present disclosure, and that piston engine 400 is an exemplary example.

In U.S. Patent Application No. 12/953,270 to Simpson et al., U.S. Patent Application No. 12/953,277 to Simpson et al., U.S. Patent Application No. 13/102,916 to Simpson et al., and to Roelle et al. Further details regarding piston engines, such as piston engines 100, 200, 300, and 400, and their operation and features are contained in U.S. Patent Application Serial No. 13/028,053, all of which are hereby incorporated by reference in their entirety .

【Self-identified Chinese style piston】

In some embodiments, the piston may include one or more features that provide self-centering relative to the cylinder of the piston engine.

FIG. 5 illustrates a perspective view of a portion of an exemplary piston assembly 500 having a self-centering feature 506, according to certain embodiments of the present disclosure. Piston assembly 500 may include piston face 502, element 504, self-centering feature 506, any other suitable component (not shown), or any combination thereof. In some embodiments, self-centering feature 506 may be part of element 504 . For example, element 504 may be a bearing element (eg, an aerostatic bearing), and self-centering feature 506 may be a machined step or other suitable feature in the bearing element. In some embodiments, self-centering feature 506 may be part of piston face 502 . For example, the self-centering feature 506 may be a step, one or more grooved indentations, a taper, or other features included in the piston assembly 500 . In some embodiments, the piston assembly may include one or more features, components, or both that facilitate centering of the piston assembly. For example, the piston assembly may include self-centering features and features that can help balance pressure on one or more sides of the piston assembly and thus can help center the piston. Although not shown in FIG. 5 , piston assembly 500 can alternatively include a piston rod, translator, piston rings, fluid bearings, any other suitable component, or any combination thereof.

6 shows a cross-sectional view of an exemplary arrangement 600 of a piston assembly 610 and cylinder 620 with blow-by gas (shown by arrow 640 ) from combustion section 630 , according to certain embodiments of the present disclosure. In certain embodiments, piston face 602 may contact combustion section 630 (exemplarily shown in FIG. 6 ), gas drive section (not shown in FIG. 6 ), any other suitable section of a cylinder of a piston engine. (not shown) or any combination thereof. Blow-by gases may flow from combustion section 630 , around piston face 602 and axially along piston assembly 610 . In certain embodiments, the interaction of blowby gas and self-centering feature 616 may be used to center piston assembly 610 . For example, a pressure distribution for centering piston assembly 610 may be generated in the gap between piston assembly 610 and cylinder 620 . Blow-by gas may be provided to the gap from a combustion section, a gas drive section or other suitable section operating at any suitable pressure, such as operating at a pressure of 20-800 bar or other suitable pressure.

FIG. 7 illustrates a cross-sectional view of an exemplary piston assembly 610 and cylinder 620 , wherein the piston assembly 610 is eccentric, according to certain embodiments of the present disclosure. The central axis 750 of the cylinder 620 represents the geometric central axis of the cylinder bore of the cylinder 620 . When the piston assembly 610 is eccentric in the cylinder 620, as shown in FIG. 7, in a cylindrical coordinate system relative to the piston assembly, along the lateral side of the piston assembly 610 (that is, at a radius that can vary with θ and z The pressure field P ₁ (R,θ,z) at R) may be circumferentially (ie in the direction of θ) inhomogeneous at a given axial position Z.

FIG. 8 illustrates a cross-sectional view of an exemplary piston assembly 610 and cylinder 620 , where piston assembly 610 is centered relative to central axis 750 , according to certain embodiments of the present disclosure. When the piston assembly 610 is centered in the cylinder 620 , as shown in FIG. 8 , P ₂ (R,θ,z) of the piston assembly 610 may be substantially uniform circumferentially at a specified axial location Z. In some embodiments, the pressure field centered on the piston may be non-uniform, but when integrated on the sides of the piston, give substantially zero resultant force. For example, a piston assembly with grooved notches may have an uneven circumferential pressure field due to the notches, but may provide zero resultant force.

FIG. 9 illustrates a cross-sectional view of a portion of an exemplary piston engine 900 having a piston assembly 910 with features 912 that may assist in its centering, according to certain embodiments of the present disclosure. In some embodiments, a feature such as feature 912 may be included in the piston assembly along with a self-centering feature (eg, any of the self-centering features of FIGS. 10-12 ). As shown in FIG. 9 , feature 912 may include one or more grooves extending around the entire perimeter of piston assembly 910 , which may help balance the pressure field in gap 950 of FIG. 9 . Feature 912 may also act as a straight-through labyrinth seal to reduce axial flow velocity in gap 950 . Although illustrated exemplarily as grooves in FIG. 9 , any suitable feature or combination thereof may be used in accordance with the present disclosure to facilitate centering.

FIG. 10 illustrates a cross-sectional view of a portion of an exemplary piston engine 1000 including a piston assembly 1010 having a notched self-centering feature 1012 and one or more slots 1014 , according to certain embodiments of the present disclosure. Self-centering feature 1012 may include one or more notches, each notch extending partially around the perimeter of piston assembly 1010 . Slots 1014 may include one or more slots (eg, corresponding to one or more notches) that may serve as guides for blow-by gas to flow into the notches. Although shown as being on the side of the piston assembly 1010, in certain embodiments, the slots may also be included on the interior of the piston assembly and may be fed from any suitable source. For example, self-centering feature 1012 may include three slotted notches, each centered 120 degrees apart on the perimeter and each extending less than 120 degrees along the perimeter, and three corresponding slots 1014 that may allow fluid Flow into the notch from a region 1060 of relatively high pressure. Any suitable arrangement of segmented notches, including any suitable number of notches, may be used in accordance with the present disclosure.

11 illustrates a cross-sectional view of a portion of an exemplary piston engine 1100 having a piston assembly 1110 having a stepped self-centering feature 1112, according to certain embodiments of the present disclosure. Self-centering feature 1112 may include a step extending around the entire perimeter of piston assembly 1110 . The steps may comprise any suitable absolute and/or relative dimensions. In the illustrated example, the clearance in the step (ie, relatively closer to the piston face 1102) may be on the order of twice the clearance at the larger diameter region of the piston assembly. In some embodiments, the piston assembly may include a segmented step arranged in a manner similar to the slotted notch in FIG. 10 , but with the notch extending through the piston face 1102 and thus need not include a slot.

12 illustrates a cross-sectional view of a portion of an exemplary piston engine 1200 having a piston assembly 1210 having a tapered self-centering feature 1212, according to certain embodiments of the present disclosure. Self-centering feature 1212 may include a taper extending around the entire perimeter of piston assembly 1210 , wherein the diameter at piston face 1202 is relatively narrowed. The taper may comprise any suitable absolute and/or relative dimensions. In the illustrated example, the clearance at the small diameter of the taper (ie, relatively closer to the piston face 1202 ) may be on the order of twice the clearance at the larger diameter region of the piston assembly. In some embodiments, the piston assembly may include more than one tapered section around the perimeter in a manner similar to the grooved recess in FIG. 10 , where the tapered portion extends through the piston face 1102 .

In some embodiments, any or all of self-centering features 1012, 1112, and 1212, feature 912, and other suitable self-centering or other features may be combined. For example, the piston assembly may include a taper, a step, and a series of grooves (eg, a labyrinth) to provide centering. The self-centering feature may be used adjacent to a piston face in contact with the combustion section, the gas drive section, the gas spring section, any other suitable piston face that allows blowby gas to flow past the piston face, or any combination thereof. For example, for the piston engine 300 labeled in FIG. 3 , a self-centering feature may be included near any piston face 312 .

【Non-contact bearing】

In some embodiments, non-contact bearings may be used between the pistons and corresponding cylinders. Non-contact bearings may include, for example, aerostatic bearings, hydrostatic bearings, or other suitable non-contact bearings that may be moving or stationary. Non-contact bearings may include a thin film of fluid that separates the piston and cylinder walls to reduce friction and associated work losses. In some embodiments, the use of aerostatic bearings may allow for oil-free operation of the piston and cylinder assemblies in piston engines, and correspondingly piston engines may not require an auxiliary oil system, which may simplify certain aspects of engine architecture . In some embodiments, non-contact bearings may include motor oil as the bearing fluid. The bearing fluid may include, for example, air, nitrogen, exhaust gas, engine oil, liquid water, water vapor, liquid carbon dioxide, gaseous carbon dioxide, hydraulic fluid, any other suitable fluid, or any combination thereof. The fluid used in fluid bearings can be supplied by piston assemblies, cylinders, or both.

13 illustrates a perspective view of a portion of an exemplary piston assembly 1300 with a bearing element 1310 having a bore 1312, according to certain embodiments of the present disclosure. The holes 1312 can be arranged in a certain pattern, arranged randomly, or any combination of the above-mentioned arrangement methods. Aperture 1312 may have any suitable size. For example, in some embodiments, apertures 1312 may range in size from a few thousandths of an inch or less to an eighth of an inch or greater. In some embodiments, the size of the holes 1312 may be selected based on the relative flow restriction or effective area of the holes to one or more other flow restrictions or effective areas. For example, the holes may be shaped to provide a flow restriction of the same order of magnitude as the flow restriction of the exhaust path of the bearing fluid downstream of the holes 1310 . Bearing elements may help maintain centering as piston assembly 1300 translates within the bore of a suitable cylinder due to forces on piston face 1302 or other suitable piston face (not shown) of piston assembly 1300 . Fluid may be provided from any suitable fluid source as indicated by arrow 1322 and may be distributed to bore 1312 in piston assembly 1300 via internal fluid passages (not shown). After exiting bore 1312 , fluid may flow through the gap and along at least a portion of piston assembly 1300 . The outward flow of fluid from bearing element 1310 as indicated by arrow 1320 may help avoid and/or reduce piston assembly-cylinder contact.

Although shown as holes in Figure 13, any suitable port may be used to provide fluid to the gap for use as a fluid bearing. For example, a gap between mating components may be used to provide fluid to the gap. In a further example, an annular orifice extending partially or completely around the circumference of the piston assembly may be used to provide fluid to the gap. In some embodiments, the bearing element 1310 may include ports that are sufficiently small (eg, smaller than the mean free path of the bearing fluid) to allow leakage.

14 illustrates a perspective view of a portion of an exemplary piston assembly 1400 having a porous bearing element 1410, according to certain embodiments of the present disclosure. Bearing elements may help maintain centering as piston assembly 1400 translates within the bore of a suitable cylinder due to forces on piston face 1402 or other suitable piston face (not shown) of piston assembly 1400 . Fluid may be provided from any suitable fluid source as indicated by arrow 1422 and may be distributed in piston assembly 1400 via internal fluid passages (not shown) and may subsequently flow through the void space in any suitable portion of bearing element 1410 . Bearing element 1410 may have any suitable porosity and pore size. After exiting the sides of the bearing element 1410 , the gas may flow through the gap and along at least a portion of the piston assembly 1400 . The outward flow of fluid from bearing element 1410 as indicated by arrow 1420 may help avoid and/or reduce piston assembly-cylinder contact. Bearing element 1410 may be constructed of any suitable material having a porosity that permits fluid flow. For example, the porous bearing element may be made of graphite, sintered metal (e.g. iron, steel, bronze), sintered or otherwise treated porous ceramic (e.g. silicon carbide, alumina, magnesia), any other suitable sintered or otherwise Processed materials or any combination thereof. In some embodiments, the bearing element 1410 may have pores of sufficiently small size (eg, smaller than the mean free path of the bearing fluid) to allow leakage.

Figure 15 illustrates a cross-sectional view of an exemplary piston assembly 1500 with a fluid bearing 1510 extending through the piston assembly 1500, according to certain embodiments of the present disclosure. Piston assembly 1500 may include piston face 1502, bearing element 1510, frame 1550, fastener 1590, any other suitable component not shown in FIG. 15, or any combination thereof. Piston assembly 1500 may be configured to fit within a bore of a cylinder of a piston engine, and may be configured to translate substantially along an axis at or near a bore centerline. Bearing element 1510 includes fluid passages 1560 that may distribute bearing fluid from one or more input ports 1512 to one or more ports or surfaces to flow radially outward as indicated by arrows 1522 . In some embodiments, bearing element 1510 may comprise an assembly of multiple components. In some embodiments, piston 1502 may optionally include self-centering features or other suitable features (not shown).

16 illustrates a cross-sectional view of an exemplary piston assembly 1610 and cylinder 1620 with a fluid bearing 1612 (eg, a fluid layer located in a gap at least partially originating from bearing element 1618 ) extending through piston assembly 1610, according to certain embodiments of the present disclosure. . Piston assembly 1610 includes an internal passage 1614 that may receive bearing fluid 1616 . Bearing element 1618 is the portion of piston assembly 1610 that includes a bore or porous portion through which bearing fluid can flow into fluid bearing 1612 . The bearing element 1618 may be an integral part of the piston (as shown in FIG. 16 ), another part of the piston assembly 1610, a separate part that fits to the piston assembly 1610 (eg, by press-fitting or mounting with fasteners), has any other suitable , or any combination thereof. Fluid bearing 1612 may help center piston assembly 1610 about axis 1650 , which represents the center of the cylinder bore of cylinder 1620 .

17 shows a cross-sectional view of an exemplary piston assembly 1710 and cylinder 1720 with a fluid bearing 1712 extending through the cylinder 1720, according to certain embodiments of the present disclosure. Cylinder 1720 includes internal passage 1714 that may receive bearing fluid 1716 . Bearing element 1718 is the portion of cylinder 1720 that includes a bore or drain surface from which fluid may flow into fluid bearing 1712 located in a suitable gap between piston assembly 1710 and cylinder 1720 . Bearing element 1718 may be an integral component of cylinder 1720 (as shown in FIG. 17 ), a separate component fitted to cylinder 1720 (such as an insert or cylinder liner), have any other suitable arrangement, or any combination thereof. Fluid bearing 1712 may help center piston assembly 1710 about axis 1750 representing the center of the bore of cylinder 1720 . In some embodiments, the cylinder may include one or more bearing elements capable of providing bearing fluid to one or more corresponding fluid bearings. For example, in some embodiments, the cylinder bore may include multiple bearing elements, each having a separate and controllable fluid source to deliver bearing fluid to multiple locations within the cylinder bore.

In certain embodiments, the blowby gas may be directed to reduce or prevent the flow of blowby gas in the gap portion near the bearing element. For example, blowby gas may be directed through the cylinder, the piston assembly, or both such that the flow of blowby gas does not substantially alter the flow of bearing fluid in the gap. Certain changes in the flow of bearing gas through, for example, the flow of others, such as blowby gas, can adversely affect the ability of the bearing fluid to prevent piston-cylinder contact. Channeling of blowby gas may, for example, allow the discharge pressure of the bearing fluid to be relatively much lower than the fluid feed pressure (eg, allow for a greater pressure drop in the bearing fluid), which may provide desired flow and bearing characteristics.

18 shows a cross-sectional view of an exemplary device 1800 of a piston assembly 1810 and cylinder 1820 with bearing elements 1812 and 1813 and a translator 1814 including a fluid passage 1875, according to certain embodiments of the present disclosure. Piston face 1802 may contact a gas spring of device 1800 (eg, a gas drive segment), while piston face 1804 may contact a combustion segment of device 1800 . Apparatus 1800 may include stator 1815 that may interact electromagnetically with translator 1814 .

In the illustrated embodiment, bearing fluid 1874 is supplied to conduit 1870 to which conduit 1872 is connected via seal 1871 . As shown in FIG. 18 , seal 1871 may allow translation of piston assembly 1810 including conduit 1872 about axis 1850 while maintaining a pressurized seal between conduits 1870 and 1872 . The interior of the conduit 1872 is coupled to a fluid channel 1875 within the translator 1814 from which bearing fluid 1874 can flow into the channel 1816 . Passage 1816 delivers bearing fluid 1874 to bearing elements 1812 and 1813 from where it flows into a fluid bearing located in the gap between piston assembly 1810 and cylinder 1820 . In some embodiments (not shown), conduit 1870, conduit 1872, or both, may be flexible to allow relative movement. For example, in some embodiments (not shown), tubing 1870 may be a flexible hose connected directly to translator 1814 via a suitable hose coupling (such as and accordingly not necessarily including tubing 1872 ).

Figure 19 shows a cross-sectional view of an exemplary arrangement 1900 of a piston assembly 1910 and cylinder 1920 with bearing elements 1912 and 1913 and a valve 1970, according to certain embodiments of the present disclosure. Piston face 1902 may contact a gas spring of device 1900 (eg, a gas drive segment), while piston face 1904 may contact a combustion segment of device 1900 . Apparatus 1900 may include stator 1915 that may interact electromagnetically with translator 1914 .

In the illustrated embodiment, at least a portion of the fluid in gas spring 1976 is supplied to passage 1916 as bearing fluid via a valve 1970 located in piston face 1902 (eg, indicated by arrow 1974). Valve 1970 may comprise an active or passive valve or other suitable multiplexer device that provides fluid flow control in one or more directions. For example, valve 1970 may include a reed valve, a ball valve, a needle valve, a ball check valve, a diaphragm check valve, a static flow restriction that provides different resistances to different flow directions in a pipeline, any other suitable valve, an electronic controller or other active positioning system, any other suitable device, or any combination thereof. Passage 1916 delivers bearing fluid 1974 to bearing elements 1912 and 1913 from where it flows into a fluid bearing located in the gap between piston assembly 1910 and cylinder 1920 . In some embodiments, valve 1970 may be a check valve. Thus, as piston assembly 1910 translates along axis 1950, and as fluid is supplied to and/or exhausted from gas spring 1976 via port 1990 (eg, which may include one or more valves), the pressure in gas spring 1976 Cracking pressure may be reached, and fluid may then flow through valve 1970 into passage 1916 . The cracking pressure of valve 1970 may be any suitable value, and may be actively adjustable in some embodiments. In some embodiments, valve 1970 may be actively controllable, and flow in either direction may be controlled by a control orifice or other flow restriction in valve 1970 .

In some embodiments, the bearing element may be an integral part of the piston. For example, the piston may have a set of machined channels and holes that provide bearing fluid to the gap. In some of these embodiments, the piston may, but need not be, be part of a piston assembly. Bearing elements may include graphite elements, metal elements with machined features, sintered metal elements, porous ceramic elements, non-porous ceramic elements, elements of any other suitable suitable material, or any combination thereof.

[Temperature management of cylinder and/or piston]

In certain embodiments, the temperature of the piston (or components thereof), the cylinder, or both may be controlled or otherwise managed. Temperature management of the piston (or components thereof) and/or cylinder may help maintain or otherwise manage clearance by managing thermal deformation of one or more components of a piston engine.

In some embodiments, one or more heated tubes may be used to affect heat transfer to the piston assembly. The heater tubes may include fluid conduits configured to facilitate heat transfer, for example, to and from components of the piston engine. The piston face of the piston assembly may experience an increase in temperature due to combustion. The use of heated tubes may facilitate heat transfer outward from the piston face, any other suitable portion of the piston assembly, or any other suitable component to reduce the operating temperature of the component. For example, the heating tube may transfer heat from the piston towards a heat reservoir such as a bearing element, a gap, a bore surface of a cylinder, a piston rod cooled by coolant, any other suitable heat reservoir or any combination thereof.

The heating tube may comprise a fluid conduit, which may be filled with a suitable fluid such as water, ethanol, ammonia, sodium, or any other suitable fluid or mixture. The latent heat associated with a phase change of a fluid is generally much greater than the measurable energy transfer due to temperature differences. Additionally, the phase change of the fluid can occur at a substantially constant or otherwise constrained temperature (which can depend on pressure and any impurities present), which can help reduce the relatively large temperature gradient. The heating tube may be arranged as a part of the piston assembly in thermal contact with the piston face of the piston assembly. In certain embodiments, the linear motion of the piston assembly with the heated tubes may assist in transporting fluid within the heated tubes, thereby facilitating heat transfer from the piston face to relatively cooler parts of the piston engine.

It should be understood that the term "thermal contact" as used between components refers to the ability to effectively transfer heat between the components. For example, a heating tube may be arranged in contact with the piston face and may transfer heat from the piston face and thus be in "direct" thermal contact with the piston face. In another example, the heating tube may be in contact with the piston frame, the piston frame may be in contact with the piston face, and the heating tube may transfer heat from the piston frame, the piston frame may transfer heat from the piston face, and thus the heating tube may be in contact with the piston The surfaces are in "indirect" thermal contact.

20 illustrates a cross-sectional view of an exemplary piston assembly 2010 and cylinder 2020 of a piston engine 2000 with a heater tube 2080 included as part of the piston assembly, according to certain embodiments of the present disclosure. Heater tube 2080 may be a pipe or other fluid conduit that may include fluid 2082 capable of undergoing a gas-to-liquid phase transition during operation of piston engine 2000 . Heat transfer (shown by arrow 2024 ) from combustion section 2030 to piston face 2002 may occur during engine operation. Further heat transfer (shown by arrow 2024 ) from the piston face 2020 to a portion 2084 of the heater tube 2080 may be performed, which may assist in reducing, maintaining, or reducing and maintaining the temperature of the piston face 2020 . Heat transfer within the heating tube 2080 from one portion 2084 of the heating tube 2080 to another portion 2086 of the heating tube 2080 may occur. The portion 2086 may transfer heat to a portion of the piston assembly 2010 remote from the piston face 2002 , such as an end of the cylinder 2020 remote from the combustion section 2030 and relatively close to the portion 2086 . For example, heater tubes 2080 may facilitate heat transfer 2024 radially outward from combustion section 2030 to bearing surfaces, gaps, and then to cylinders where heat may be further transferred, eg, via coolant in coolant passages. In another example, heater tube 2080 may facilitate heat transfer from combustion section 2024 to gas drive section 2040 of cylinder 2020 .

21 illustrates a cross-sectional view of an exemplary piston assembly 2100 in which a heater tube 2180 is formed by a void within, according to certain embodiments of the present disclosure. Piston assembly 2100 may include piston 2102, element 2110, frame 2150, fastener 2190, any other suitable components not shown in FIG. 21, or any combination thereof. Piston assembly 2100 may be configured to fit within a bore of a cylinder of a piston engine, and may be configured to translate substantially along an axis at or near a bore centerline. Element 2110 may include (although not shown) a bearing element (eg, having a bearing channel), a piston ring, a frame, any other suitable component, any other suitable feature, or any combination thereof. Fluid within heated tube 2180 may be filled, drained, or otherwise regulated using port 2182, which may include a valve (eg, check or shutoff valve), plug, or other component. In certain embodiments, heated tube 2180 having port 2182 may be charged, drained, or otherwise regulated during operation of the piston engine. In certain embodiments, heated tube 2180 with port 2182 need not be charged, drained, or otherwise adjusted while the piston engine is running, and can be adjusted accordingly when the piston engine is not running.

In some embodiments, a plurality of heating tubes may be included on the diameter near the periphery of the piston assembly to assist in heat transfer from the piston face to the gap and the cylinder inner wall. In the illustrated example, six to twelve heating tubes may be axially oriented, disposed on a diameter near the periphery of the piston assembly, although any suitable number of heating tubes may be used in such an annular arrangement. In some embodiments, an annular heater tube may be included in the piston assembly to facilitate heat transfer to the gap. For example, an annular space within the piston assembly may be filled with a suitable fluid and sealed during operation.

22 illustrates a cross-sectional view of an exemplary piston engine 2200 including a piston assembly 2210 and a cylinder 2220 having coolant passages 2222 and 2238 and heated tubes 2224, according to certain embodiments of the present disclosure. In certain embodiments, piston engine 2200 may include coolant passages 2222 to help control or otherwise limit the temperature of one or more components of piston engine 2200 . Temperature control may also be used to control the size and/or shape of the cylinder bore (eg, by controlling thermal deformation), which may improve or otherwise tune blowby gas properties and/or bearing performance. As exemplarily shown in FIG. 22, cylinder 2220 may include internal passages fed through one or more ports, which may supply and return cooling fluid as indicated by arrows 2230 and 2234 and arrows 2232 and 2236, respectively. As shown, coolant passage 2222 and coolant passage 2238 include annular voids, although any suitable arrangement may be used in accordance with the present disclosure. In certain embodiments, a coolant such as ethylene glycol, propylene glycol, water, alcohol, air, any other suitable fluid, or any combination thereof (eg, ethylene glycol diluted with water) may be provided to coolant channels 2222 and 2238 . In certain embodiments (not shown), piston engine 2200 may include a coolant subsystem, which may include a pump, radiator, thermostat, pressure regulator, fluid regulation conduits, any other suitable components, or random combination. In certain embodiments, coolant passage 2222 and coolant passage 2238 may be interconnected within cylinder 2220 and accordingly may be controlled as a single collection of conduits. In certain embodiments, the coolant passage 2222 and the coolant passage 2238 need not be interconnected within the cylinder 2220 and can be controlled independently. For example, in certain embodiments, coolant passage 2222 and coolant passage 2238 may facilitate selective cooling of different regions of cylinder 2220, and thus each region may be cooled individually. In an exemplary example, the control system may determine if the clearance between piston assembly 2210 and cylinder 2220 is excessive when the piston is in combustion section 2270 . Accordingly, the flow rate of coolant provided to coolant passage 2222 closer to TDC than coolant passage 2238 may be increased to cool the cylinder and (by thermal shrinkage) reduce the cylinder bore, thereby reducing the gap. Any suitable number of individual coolant passages may be used to provide selective cooling in accordance with the present disclosure, arranged in any suitable configuration. In certain embodiments, cylinder 2220 may include one or more heated tubes 2224 to help control or otherwise limit the temperature of one or more components of piston engine 2200 . The cylinder 2220 may include one or more heated tubes 2224 in any suitable arrangement, and any suitable heated tube fluid may be included in the heated tubes. For example, the one or more heating tubes 2224 may comprise a plurality of heating tubes disposed axially on a diameter centered on the center of the cylinder bore of the cylinder 2220 . In another example, the one or more heated tubes 2224 may comprise an annular space within the cylinder 2220 . Heated tubes 2226 may be used in some embodiments to supply, drain, or otherwise control fluid within one or more heated tubes 2224 . For example, heated tubes 2226 may include valves, regulators, orifices, any other suitable features or devices, or any combination thereof to control properties of one or more heated tubes 2224 or fluid contained therein. In some embodiments, coolant channel 2222 and/or coolant channel 2238 may directly contact (not shown) one or more heating tubes 2224 and may provide relatively enhanced heating from one or more heating tubes. 2224 heat transfer. Although coolant passages 2222 and 2238 and one or more heating tubes 2224 are shown in FIG. 22 , certain embodiments (not shown in FIG. 22 ) may include coolant passages and one or more heating tubes. One and correspondingly need not include both. Using coolant passages 2222 and 2238 together with one or more heating tubes 2224 may provide relatively enhanced heat transfer in certain arrangements compared to either alone. For example, heat can be transferred from the cylinder bore of the cylinder 2220 to the one or more heating tubes 2224 via the gap, and the one or more heating tubes 2224 can transfer at least some of this heat to the coolant passage 2222 and/or cooling Coolant within coolant passage 2238 (eg, heat transfer may include conduction through a portion of cylinder 2220).

In some embodiments, the fluid provided to any port 2250 may be used to cool the piston assembly 2210 or various parts thereof. For example, heat from the piston face of piston assembly 2210 can be delivered to the piston rod of piston assembly 2210 and fluid sent to any port 2250 can convectively cool the piston rod of piston assembly 2210 .

In certain embodiments, fluid bearings may assist in cooling the piston assembly, cylinder, components therein, any other suitable component in a piston engine, or any combination thereof. Bearing fluid may be provided to a bearing element which may direct the bearing fluid directly to a suitable clearance in the piston-cylinder assembly. The bearing fluid may help cool at least a portion of the piston-cylinder assembly as it flows through the gap. In certain embodiments, the bearing fluid may flow substantially from the combustion section through the gap and, in turn, may remove heat from the combustion section, thereby reducing the temperature of one or more components of the piston engine. In certain embodiments, convection of bearing fluid across the gaps of the piston engine may increase the effective rate of heat transfer between the piston face and another portion of the piston assembly and/or cylinder. In some embodiments, one or more heated tubes may be included in the piston assembly with bearing elements. The one or more heating tubes can help to keep the bearing element or a portion thereof at a nearly constant temperature, which can help control thermal expansion and related changes in the gap. In certain embodiments, the use of one or more heating tubes, coolant passages, bearing elements, any other suitable components, or any combination thereof may assist in managing the heat of one or more components of a piston engine Morph to maintain or otherwise manage gaps.

【Cylinder liner】

In some embodiments, the clearance between the free piston and the cylinder may be controlled or otherwise managed. In some embodiments, a deformable cylinder liner may be used to adjust the clearance by adjusting the cylinder bore in which the piston assembly moves. In certain embodiments, the cylinder liner fluid may be used to apply pressure to a deformable cylinder liner that may deform based on the pressure differential between the various faces of the cylinder liner. The cylinder liner fluid may include, for example, water, ethylene glycol, propylene glycol, motor oil, hydraulic fluid, fuel (eg, diesel fuel), any other suitable fluid, or any suitable combination thereof.

23 illustrates a cross-sectional view of an exemplary piston assembly 2310 and cylinder 2320 with a deformable cylinder liner 2330, according to certain embodiments of the present disclosure. The inner surface of the deformable cylinder liner 2330 can define a cylinder within which the piston assembly 2310, or a portion thereof, can translate along an axis 2350 at the center of the cylinder. A channel 2322 may be formed between the cylinder 2320 and the deformable cylinder liner 2330 , and liner fluid may be routed into and/or returned from the channel 2322 via port 2324 . Liner fluid, controlled to an appropriate pressure, applies a deforming force to the deformable cylinder liner 2330 to allow adjustment of the cylinder bore accordingly. The gap 2360 between the cylinder bore and piston assembly 2310 can be adjusted accordingly by applying cylinder liner fluid at an appropriate pressure. Increasing the pressure of the cylinder liner fluid (e.g., by supplying cylinder liner fluid to passage 2322 via one or more ports 2324) can reduce the cylinder bore and gap 2360, while (e.g., by exhausting the cylinder liner fluid from passage 2322 via one or more ports 2324) fluid) Reducing cylinder liner fluid pressure can increase cylinder bore and clearance 2360.

FIG. 24 illustrates a cross-sectional view of the exemplary piston assembly 2310 and cylinder 2320 of FIG. 23 with a deformable cylinder liner 2330 undergoing deformation, according to certain embodiments of the present disclosure. The pressure of the cylinder liner fluid is greater in passage 2322 as shown in FIG. 24 than in passage 2322 as shown in FIG. 23 , and thus gap 2460 is relatively smaller than gap 2360 .

25 shows a cross-sectional view of an exemplary piston assembly 2510 and cylinder 2520 with a segmented deformable cylinder liner 2530, according to certain embodiments of the present disclosure. The inner surface of the deformable cylinder liner 2530 can define a cylinder within which the piston assembly 2510, or a portion thereof, can translate along an axis 2550 at the center of the cylinder. Channels 2522 and 2523 may be formed between cylinder 2520 and deformable cylinder liner 2530 and may be separated by seal 2532 . Cylinder liner fluid may be supplied to and/or returned from passages 2522 and 2523 via ports 2524 and 2525, respectively, which may, but need not, be isolated from each other. Liner fluid controlled to an appropriate pressure can apply a deforming force to the deformable cylinder liner 2530 to allow adjustment of each segment of the cylinder bore (ie, the portion of the bore corresponding to passage 2522 or 2523 ) accordingly. In some embodiments, since the deformation of the deformable cylinder liner 2530 may depend on the pressure differential between the liner fluid and the cylinder bore, the pressure of the liner fluid may be based at least in part on the pressure within the appropriate section of the cylinder Take control. The gap 2560 between the cylinder bore and piston assembly 2510 can be adjusted accordingly by applying cylinder liner fluid at an appropriate pressure. Because the gap corresponding to each channel 2522 and 2523 can be adjusted independently, the gap can vary in an axial direction (ie, parallel to axis 2550). For example, in some embodiments, as the piston 2512 travels through a segment of the deformable cylinder liner 2530, the gap at that segment can be adjusted. increasing the pressure of the cylinder liner fluid (e.g., by supplying cylinder liner fluid to passages 2522 and/or 2523 via one or more corresponding ports 2524 and/or 2525) can reduce the cylinder bore and gap 2560 at one or more locations, Instead, reducing the pressure of the cylinder liner fluid (for example, by exhausting the cylinder liner fluid from passages 2522 and/or 2523 through one or more corresponding ports 2524 and/or 2525) can increase the cylinder bore and clearance at one or more locations. 2560.

26 illustrates a cross-sectional view of an exemplary piston engine 2600 having a deformable cylinder liner 2630, according to certain embodiments of the present disclosure. A passage 2622 may be formed between the cylinder 2620 and the deformable cylinder liner 2630 , and cylinder liner fluid may be sent into and/or returned from the passage 2622 via port 2624 . Liner fluid, controlled to an appropriate pressure, applies a deforming force to the deformable cylinder liner 2630 to allow adjustment of the cylinder bore accordingly. In the illustrated embodiment, ports 2626 (eg, which may provide fuel and/or air or receive exhaust gas) may be located on the outside of deformable cylinder liner 2630 to eliminate the need for ports or other openings in deformable cylinder liner 2630 demand. Adjustment of the gap between the piston assembly 2610 and the deformable cylinder liner 2630 can be achieved by adjusting the pressure of the cylinder liner fluid in the passage 2622 .

In some embodiments, the flow of cylinder liner fluid may be used to provide cooling to the deformable cylinder liner. For example, a pressure-controlled and flow-controlled liner fluid may be used to provide convective heat transfer from a deformable liner (eg, near the combustion section) to the liner fluid. Cooling through the use of cylinder liner fluid may be applied in conjunction with or instead of cooling through the use of coolant passages and/or heating tubes (such as shown in FIG. 22 ).

27 shows a cross-sectional view (perpendicular to the cylinder bore axis) of a portion of an exemplary piston engine 2700 with localized coolant passages 2752 and 2754, according to certain embodiments of the present disclosure. Cylinder 2720 of piston engine 2700 may include one or more plenum chambers 2722 that can be coupled to one or more throttle valves 2724 and one or more throttle valves 2726 . In certain embodiments, throttle fluid may flow from one or more plenums 2722 through one or more throttle valves 2724 into a coolant passage 2752 configured to cool region 2732 (such as the exemplary in coolant passage 2752 indicated by the arrow). In certain embodiments, throttle fluid may flow from one or more plenums 2722 through one or more throttle valves 2726 into a coolant passage 2754 configured to cool region 2734 (such as the exemplary in coolant passage 2754 indicated by the arrow). The one or more throttles 2724 and 2726 may include a fixed flow restriction orifice, an adjustable flow restriction orifice, a controllable throttle, any other suitable fluid restriction feature, or any combination thereof. One or more throttle valves 2724 and 2726 may cause a reduction in the pressure of the throttle fluid, which may also result in a reduction in the temperature and/or enthalpy of the throttle fluid. The reduced fluid temperature and/or enthalpy may enhance heat transfer from the bore of the cylinder 2720 (such as the illustrated bore configured to house the piston assembly 2710). In certain embodiments, coolant passages 2752 and 2754 may include tubular passages, manifolds, or other flow-guiding components to provide flow of throttled fluid from one or more throttle valves 2724 and 2726 to the local space region of cylinder 2720. flow, and then return the fluid to the fluid control system (eg, which may include a return line and container). Piston engine 2700 may include any suitable number of plenums 2722, which may, but need not, be interconnected. For example, plenum 2722 may include multiple plenums, each independently controllable to provide selectable cooling to localized regions of cylinder 2720 . In another example, plenum 2722 may include a single plenum that may be coupled to multiple throttle valves to provide selectable cooling to localized regions of cylinder 2720 . Multiple throttles may be independently controllable, or otherwise have characteristic flow-restricting properties to control cooling of one or more localized regions of cylinder 2720 . In certain embodiments, cooling the cylinder 2720 with a throttling fluid may allow control of the cylinder temperature as well as the clearance between the cylinder 220 and the piston assembly 2710 . In certain embodiments, direct or indirect measurements of cylinder geometry (eg, size, shape, or both) may be used by the control system to control cooling through local coolant passages 2752 and 2754 . For example, higher operating temperatures may be expected near combustion section 2730, near TDC, and enhanced cooling may be provided to region 2732 to limit the temperature domain. In another example, region 2732 may be provided with reduced cooling in some cases to increase the corresponding cylinder bore and associated clearance. Increased or decreased cooling may be provided by increasing or decreasing the throttle action of the throttle valve, adjusting the temperature of the throttle fluid, adjusting the flow rate of the throttle fluid, any other suitable adjustment, or any combination thereof. The throttle fluid may comprise any suitable coolant fluid, which may be a liquid or a gas. For example, the throttling fluid may include ethylene glycol, propylene glycol, water, alcohol, air, any other suitable fluid, or any combination thereof (eg, ethylene glycol diluted with water). Cylinder 2720 may include any suitable port 2770 for supplying or exhausting fluid, such as air, fuel, exhaust, or a combination thereof, to or from a suitable section of piston engine 2700 .

28 shows a cross-sectional view (parallel to the cylinder bore axis) of a portion of an exemplary piston engine 2800 with localized coolant passages 2826, according to certain embodiments of the present disclosure. Piston engine 2800 may include a cylinder 2820 having a plenum 2822 . Cylinder 2820 may include a cylinder configured to receive piston assembly 2810 configured to move substantially linearly in a direction substantially parallel to the product of vectors 2850 and 2860 . Although illustrated in FIG. 28 as an annular plenum, the plenum 2822 may comprise any suitable conduit shape configured to provide any suitable flow path. Coolant may flow through throttle 2824 and into local coolant passages 2826 to cool corresponding spatial regions in cylinder 2820 . In the illustrated embodiment, coolant flows radially inward from throttle valve 2824 (shown by four radially inwardly pointing arrows in FIG. The direction given (2850x2860 perpendicular to the plane of Figure 28) flows. The return flow path of the coolant is not shown in FIG. 28 and may include radial, axial, or both flow paths. In certain embodiments, throttle valve 2824 may generate a fluid jet in localized fluid passage 2826 that may impinge on a region of space within cylinder 2820 resulting in relatively enhanced convective heat transfer in that region. Although illustrated in FIG. 28 as having four symmetrical partial coolant passages 2826, the piston engine 2800 may include any suitable number, in any suitable symmetrical or asymmetrical configuration, at any suitable axial location, and Local coolant passages coupled to any suitable number of plenums or other coolant sources.

29 illustrates a cross-sectional view of a portion of an exemplary piston engine 2900 with localized heat sources including electric heaters 2922, 2923, 2924, 2925, 2926, and 2927, according to certain embodiments of the present disclosure. Each electrical heater 2922, 2923, 2924, 2925, 2926, and 2927 may include one or more electrical leads used by an appropriate control system to control voltage, current, electrical power, or a combination thereof, supplied to the heater. For example, electric heaters 2922 and 2923 may be used individually or in combination to provide heating to region 2932 near combustion section 2930 (eg, to increase the gap between cylinder 2920 and piston assembly 2910). In another example, electric heaters 2924, 2925, 2926, and 2927 may be used to heat corresponding regions 2934 and 2936. Localized heat sources such as electric heaters may be used to provide relatively rapid thermal control of one or more spatial regions of the cylinder. In certain embodiments, direct or indirect measurements of cylinder geometry (eg, size, shape, or both) may be used by the control system to control localized heat sources. For example, each of electric heaters 2922, 2923, 2924, 2925, 2926, and 2927 may be responsive by a control system to sensed temperature, pressure, clearance, blowby gas properties, work interaction, any other suitable indicator, or Any combination to control individually. Cylinder 2920 may include any suitable port 2970 for supplying or exhausting fluid, such as air, fuel, exhaust, or a combination thereof, to or from a suitable section of piston engine 2900 .

30 shows a cross-sectional view of a portion of an exemplary piston engine 3000 including fluid passages 3022 and 3024 that may be used for heating, cooling, or both, according to certain embodiments of the present disclosure. In certain embodiments, heating fluid, cooling fluid, or both may be supplied to fluid channels 3022 and 3024, which may, but need not, be interconnected. For example, fluid may be supplied to and exhausted from fluid channels 3022 and 3024 as shown by the four arrows in FIG. 30 (eg, for an annular fluid channel with supply and return ports). In some embodiments, fluid channels 3022 and 3024 may be localized heat sources. For example, fluid channels 3022 and 3024 may be independently controllable to provide heating to respective regions 3032 and 3034 . Fluid passages 3022 and 3024 may provide heating by serving as conduits for heating fluid, which may include, for example, previously heated coolant, exhaust fluid (such as high temperature combustion products from a combustion section), any other suitable heating fluid or any combination thereof. In certain embodiments, fluid passages 3022 and 3024 may be used to heat and cool the volumetric region of cylinder 3020 . For example, heating fluid may be provided to fluid channel 3022 to increase the temperature of region 3032 (eg, to increase cylinder bore diameter and clearance), while cooling fluid may be provided to fluid channel 3024 to decrease the temperature of region 3034 (eg, to reduce cylinder diameter and clearance). In another example, heating fluid or coolant may be provided to fluid channel 3022 based on a determination by the control system. Cylinder 3020 may include any suitable port 3070 for supplying or exhausting fluid, such as air, fuel, exhaust, or a combination thereof, to or from a suitable section of piston engine 3000 .

In certain embodiments, the cylinder may be configured to undergo thermal deformation corresponding to the controlled temperature of the cylinder or changes thereof such as described in the context of FIGS. 22 and 27-30 . The controlled temperature or change thereof may correspond to a local spatial area of the cylinder. The use of coolant, heating fluid, throttle fluid, resistive heaters, any other suitable component or feature for controlling temperature, or any combination thereof may allow the control system to control one or more properties of the piston engine, such as clearance .

[combination of various methods]

In some embodiments, two or more of the above approaches may be combined. Self-centering features, fluid bearings, heated tubes, coolant channels, deformable cylinder liners, and any other suitable components or features may be suitably combined to achieve a piston engine according to the present disclosure.

For example, FIG. 31 illustrates a perspective view of a portion of an exemplary piston assembly 3100 having a seal 3104, a fluid bearing element 3108, and a self-centering feature 3106, according to certain embodiments of the present disclosure. Piston assembly 3100 may include piston face 3102, seal 3104, self-centering feature 3106, fluid bearing element 3108, any other suitable component (not shown), or any combination thereof. In some embodiments (as shown), self-centering feature 3106 may be part of seal 3104 . For example, the seal 3104 may include a self-centering feature 3106, which may be a machined step or other suitable feature in the bearing element. In some embodiments (not shown), self-centering feature 3106 may be part of piston face 3102 . For example, self-centering feature 3106 may be a step, one or more slotted indentations, a taper, or other features included in piston assembly 3100 . Gas supplied from any suitable fluid source may be distributed in piston assembly 3100 via internal fluid passages (not shown), and may then flow through fluid bearing element 3108 (shown as porous in FIG. 31 , but any suitable bearing may be used). element) any suitable part.

In another example, FIG. 32 illustrates a cross-sectional view of an exemplary piston engine 3200 with a piston assembly 3210 having a bearing element 3214, a heated tube 3250, and a self-centering feature 3212, and wherein the The cylinder 3230 has a deformable cylinder liner 3232 and coolant passages 3236 . Piston assembly 3210 may be configured to translate within a cylinder formed by deformable cylinder liner 3232 having gap 3260 . Applied cylinder liner fluid controlled at an appropriate pressure may be provided to passage 3234 via port 3233 to adjust clearance 3260 . Bearing fluid may be provided to passage 3218 and flow from bearing element 3214 and into gap 3260 to help center piston assembly 3210 within the cylinder bore. Self-centering feature 3212 can help center piston assembly 3210 within the cylinder. A suitable coolant may be provided to coolant passages 3236 in cylinder 3230 to remove heat from cylinder 3230 or portions thereof. A heated tube 3250 with a fill port 3282 can facilitate heat transfer from the piston face 3202 to another portion of the piston assembly 3210 where it is dissipated. Port 3270 may be used to supply oxidant and/or fuel, supply and/or exhaust drive gas, or exhaust exhaust from a section of the cylinder. In some embodiments, a combination of one or more approaches may require consideration of one or more additional factors. For example, in some embodiments, the piston assembly may include a self-centering feature configured to utilize blowby gas to provide a self-centering force and a bearing element configured to provide bearing fluid to the gap. The self-centering feature may thus require a portion of the blowby gas to flow along the gap to provide the self-centering force. Under certain conditions, the flow of blowby gas in the gap may affect the performance of the bearing components by changing the flow pattern of the bearing fluid in the gap. Thus, in some embodiments having a bearing element behind the self-centering feature (relative to the combustion section), the blowby gas may be absorbed after traversing the portion of the gap near the self-centering feature but before entering the portion of the gap near the bearing element. Boot out of the gap. Additionally, in some arrangements, the bearing element may include self-centering features and a collection of holes extending to the piston face for directing bearing fluid. Thus, in some of these embodiments, no means of directing blowby gas away from the gap need be employed. The previous examples can optionally be applied to a gas driven segment in addition to or in addition to the combustion segment.

[Control of gaps and/or other properties]

In certain embodiments, one or more aspects of the operation of the piston engine may be controlled or otherwise managed to affect the temperature, clearance, any other suitable property, or any combination thereof of the piston engine. In certain embodiments, controlling the temperature, pressure, or other suitable properties of the piston engine may assist in managing clearances in the piston engine. For example, relatively large temperature differences can cause deformation, eg expansion, of certain components of a piston engine, which can affect clearances. Controlling temperature differentials and/or temperature domains can help reduce deformation and, in turn, can help manage gaps. Managing gaps may include managing any other suitable property that can affect gaps.

FIG. 33 is a block diagram of an exemplary control device 3300 for a piston engine 3340 according to certain embodiments of the present disclosure. Control system 3310 may be in communication with one or more sensors 3330 coupled to piston engine 3340 . Control system 3310 may be configured to communicate with auxiliary systems 3320 , which may be used to regulate various aspects or properties of piston engine 3340 . In some embodiments, control system 3310 may be configured to interact with a user through user interface system 3350 .

Control system 3310 may include processing device 3312, communication interface 3314, sensor interface 3316, control interface 3318, any other suitable components or modules, or any combination thereof. Control system 3310 may be implemented at least in part in one or more computers, terminals, consoles, handheld devices, modules, any other suitable interface devices, or any combination thereof. In some embodiments, as shown in FIG. 33 , components of the control system 3310 may be communicatively coupled via a communication bus 3311 . Processing device 3312 may include a processor (e.g., a central processing unit), cache memory, random access memory (RAM), read only memory (ROM), capable of processing piston engine 3340 related information received from sensor 3330 via sensor interface 3316 Any other suitable components or any combination thereof. The sensor interface 3316 may include a power supply for powering the sensor 3330, a signal modulation device, a signal pre-processor, any other suitable components, or any combination thereof. For example, sensor interface 3316 may include filters, amplifiers, samplers, and analog-to-digital converters for modulating and preprocessing signals from sensors 3330 . The sensor interface 3316 can communicate with the sensor 3330 via a communication coupling 3319, which can be a wired connection (such as using IEEE 802.3 Ethernet or a Universal Serial Bus interface), a wireless coupling (such as using IEEE 802.11 "Wi-Fi" or Bluetooth), optical coupling, inductive coupling, any other suitable coupling means, or any combination thereof. The control system 3310, and more specifically the processing device 3312, may be arranged to provide control of the piston engine 3340 over a relevant time scale. For example, changes in one or more temperatures may be controllable in response to one or more sensed engine operating parameters, and control may be provided on time scales relevant to the operation of the piston engine (e.g., responding quickly enough to avoid overheating and/or component failure).

Sensors 3330 may include any suitable type of sensor that may be configured to measure any suitable property or aspect of piston engine 3340 . In some embodiments, the sensors may include one or more sensors configured to measure some aspect and/or system property of the auxiliary system 3320 . In some embodiments, the sensor 3330 may comprise a temperature sensor (such as a thermocouple, a resistive temperature sensing device, a thermistor, or an optical temperature sensor) configured to measure the temperature of a component of the piston engine 3340, introducing a piston-type The temperature of the engine 3340 or fluid recovered from the piston engine 3340 or both. In some embodiments, sensor 3330 may include one or more pressure sensors (eg, piezoelectric pressure transducers) configured to measure pressure in a section of piston engine 3340 (eg, ), the pressure of the fluid introduced into or withdrawn from the piston engine 3340, or both. In some embodiments, sensors 3330 may include one or more force sensors (e.g., piezoelectric force transducers) configured to measure forces within piston motor 3340, such as tension, compression, or shear ( For example, information may indicate friction or other relevant forces). In certain embodiments, sensors 3330 may include one or more current and/or voltage sensors (such as ammeters and/or voltmeters coupled to the LEM of piston engine 3340) configured to measure voltage, current, output Work and/or input work (eg, current multiplied by voltage), any other suitable electrical property of piston engine 3340 and/or auxiliary system 3320 , or any combination thereof.

Control interface 3318 may include a wired connection (e.g., using IEEE 802.3 Ethernet or a Universal Serial Bus interface), wireless coupling (e.g., using IEEE 802.11 "Wi-Fi," Bluetooth, or other RF communication protocols), optical coupling, inductive coupling , any other suitable coupling means, or any combination thereof, for communicating with one or more auxiliary systems 3320 . In some embodiments, control interface 3318 may include a digital-to-analog converter to provide analog control signals to any or all of auxiliary systems 3320 .

Auxiliary systems 3320 may include cooling system 3322 , pressure control system 3324 , gas drive control system 3326 , and/or any other suitable control system 3328 . Cooling/heating system 3322 may include pumps, fluid containers, pressure regulators, bypass devices, radiators, fluid conduits, electrical power circuits (e.g., for electric heaters), any other suitable components, or any combination thereof to provide a piston engine The 3340 provides cooling, heating, or both. Pressure control system 3324 may include pumps, compressors, fluid containers, pressure regulators, fluid conduits, any other suitable components, or any combination thereof to provide (and optionally receive) pressure-controlled fluid to piston engine 3340 . Gas drive control system 3326 may include a compressor, a gas container, a pressure regulator, fluid conduits, any other suitable components, or any combination thereof to provide (and optionally receive) drive gas to piston engine 3340 . In certain embodiments, other systems 3328 may include valved systems such as cam-operated systems or solenoid systems to provide oxidant and/or fuel to piston engine 3340 .

User interface 3315 may include a wired connection (e.g., Ethernet or Universal Serial Bus interface using IEEE 802.3, a ring-sealed RCA type connection), wireless coupling (e.g., using IEEE 802.11 "Wi-Fi", infrared, or Bluetooth), Optical coupling, inductive coupling, any other suitable coupling means, or any combination thereof, for communicating with one or more user interface systems 3350 . User interface system 3350 may include display 3352, keyboard 3354, mouse 3356, audio device 3358, any other suitable user interface device, or any combination thereof. The display 3352 may include a display screen such as a cathode ray tube display screen, a liquid crystal display screen, a light-emitting diode display screen, a plasma display screen, any other suitable display screen capable of providing graphics, text, images or other visual information to the user, or any combination thereof . In some embodiments, the display 3352 can include a touch screen, which can provide touch interaction with the user by, for example, presenting one or more software instructions on the display screen. Display 3352 may display any suitable information about piston engine 3340, control system 3310, auxiliary system 3320, user interface system 3350 (e.g., a time series of a property of piston engine 3340), any other suitable information, or any other suitable information thereof. combination. Keyboard 3354 may include a QWERTY keyboard, a numeric keypad, any other suitable set of hardware command buttons, or any combination thereof. Mouse 3356 may comprise any suitable pointing device capable of controlling a cursor or icon on a graphical user interface displayed on a display screen. Mouse 3356 may include a handheld device (eg, capable of movement in two or three dimensions), a touchpad, any other suitable pointing device, or any combination thereof. Audio device 3358 may include a microphone, microphone, headphones, any other suitable device for providing and/or receiving audio signals, or any combination thereof. For example, audio device 3358 may include a microphone, and processing device 3312 may process audio instructions received via user interface 3315 generated by a user speaking into the microphone.

In some embodiments, control system 3310 may be configured to provide manual control by receiving one or more user inputs. For example, in some embodiments, control system 3310 may override automatic control settings based on sensor feedback and base control signals for assistance system 3320 on the basis of one or more user inputs to user interface system 3350 based on. In another example, a user may enter setpoints for one or more control variables (e.g., temperature, pressure, flow rate, work input/output, or other variables), and control system 3310 may perform based on the setpoints. control algorithm.

In some embodiments, the operating characteristics (ie, the set of desired property values of the piston engine 3340 or auxiliary system 3320) may be predefined by the manufacturer, the user, or both. For example, specific operating characteristics may be stored in memory of the processing device 3312 and may be accessed to provide one or more control signals. In some embodiments, one or more operational features may be altered by a user. Apparatus 3300 may be used to maintain, adjust, or otherwise manage the described operating characteristics.

34 is a flowchart 3400 of exemplary steps for adjusting clearances of a piston engine according to certain embodiments of the present disclosure.

Step 3402 may include utilizing sensor 3330 to detect a gap indicator. Gap indicators can be temperature (e.g., of coolant, heating fluid, cylinder, piston, or other component or part thereof), pressure, force, distance (e.g., gap), work interaction (e.g., electromagnetic work output), material (e.g., blowby gas or its properties), any other suitable detectable property, or any combination thereof. The sensor interface 3316 may receive and/or pre-process the status of the gap indicator from the sensor 3330 and output sensor signals to the processing device 3312 . In some embodiments, clearance indicators may be stored and associated with one or more operating states of the piston engine. For example, cylinder temperature can be correlated to fuel flow and stored as a mathematical expression or table. Accordingly, step 3402 may include detecting one or more operating conditions of the piston engine and recalling stored cylinder temperature values that may be used for further processing.

Step 3404 may include processing device 3312 determining a control response based at least in part on the gap indicator detected in step 3402 . Processing device 3312 may receive sensor signals from sensor interface 3316 and perform one or more processing functions based on the sensor signals. Processing functions may include entering sensor signal values in formulas or other mathematical expressions, using sensor signal values in look-up tables or other databases, any other suitable processing, or combinations thereof. The processing device 3312 may determine a control response based on the output of one or more processing functions. For example, the calculated value may be compared to a predetermined threshold to determine an appropriate control response. In another example, one or more calculated values may be input into a control algorithm, such as a proportional-integral-derivative (PID) control algorithm, and one or more control signal values may then be determined.

Step 3406 may include processing device 3312 providing a control signal to one or more auxiliary systems 3320 using control interface 3318 based at least in part on the control response determined in step 3404 . The control signal may be an analog signal, a digital signal, or a combination thereof (such as a combination of an analog signal and a digital timing signal), which may be provided as an electrical signal (such as with a cable), an electromagnetic signal (such as with an IEEE 802.11 "Wi-Fi" or Bluetooth receiver/transmitter), optical signals (eg using fiber optic cables), inductive signals (eg using suitable induction coils), or other suitable signal types.

Step 3408 may include one or more auxiliary systems 3320 receiving the control signal obtained at step 3406 for adjusting clearance or other properties of piston engine 3340 . One or more auxiliary systems 3320 may adjust pressure, temperature, flow rate, flow route, current, voltage, electrical power, effectuate any other suitable adjustment, or any combination thereof based on the provided control signals. As indicated by the dashed arrows in FIG. 34, any or all of steps 3402-3408 may be repeated to allow closed loop control. In some embodiments, an open-loop approach may be used, where step 3402 may (but need not) be omitted, and steps 3404-3408 are performed open-loop.

In certain arrangements, the temperature domain of the piston engine's cylinder and/or piston assembly, or fluid contained therein, may be a primary and convenient indicator of clearance, and the temperature domain may be actively adjusted accordingly to adjust clearance. In an illustrative example, step 3402 may include detecting a temperature such as a cylinder temperature or a temperature of a coolant (eg, coolant provided to a coolant passage of a cylinder of a piston engine). Step 3404 may include determining how to adjust the temperature domain to maintain or otherwise manage the gap, while step 3406 may include providing corresponding control signals to appropriate auxiliary systems. For example, cylinder temperature can be increased by reducing the flow rate of coolant, which can increase the clearance through thermal expansion. In another example, cylinder temperature may be reduced by increasing coolant flow rate, which may reduce clearances through thermal contraction. In another example, the flow of coolant or heating fluid in more than one set of fluid passages may be adjusted to control the temperature domain of multiple regions in the cylinder (see, eg, FIG. 22 ). Referring to the previous example, based on the control signal of step 3406, by adjusting, for example, the flow control valve, the speed of the pump, the bypass flow control valve, the pressure regulator, any other suitable control device for controlling the flow rate, or any combination thereof Regulates the flow of coolant or heating fluid. In another illustrative example, step 3402 may include detecting a temperature such as a temperature of a heated tube within a cylinder of a piston engine (eg, a temperature of the heated tube or a heated tube fluid therein). Step 3404 may include determining how to adjust the temperature domain to maintain or otherwise manage the gap, while step 3406 may include providing corresponding control signals to appropriate auxiliary systems. For example, the heater tube temperature can be increased by increasing the pressure of the fluid within the heater tube (eg, by adding fluid to the heater tube or reducing the volume of the heater tube), which can increase the gap. In another example, the heater tube temperature can be reduced by reducing the pressure of the heater tube (eg, by draining fluid from the heater tube or increasing the volume of the heater tube), which can reduce the gap. Referring to the previous example, based on the control signal of step 3406, by adjusting, for example, a flow control valve, a pressure regulator, a check valve, any other suitable control device for controlling the pressure of the heating tube, and an appropriate Fluid ports or any combination thereof to adjust the properties of the fluid within the heated tube (eg, with fluid ports or other adjustable features).

35 is a flowchart 3500 of exemplary steps for adjusting one or more properties of a piston engine according to certain embodiments of the present disclosure.

In some embodiments, one or more sensors 3330 may be utilized to detect gap indicators. Sensor interface 3316 may receive raw signals from sensors 3330 and provide sensor signals to processing device 3312 . For example, step 3502 may include detecting cylinder temperature of piston engine 3340 using a temperature sensor such as a thermocouple positioned in contact with or near a portion of the cylinder (eg, near a combustion section). In some cases, an increase in cylinder temperature may indicate insufficient cooling that can affect clearances. In another example, step 3504 may include detecting piston temperature of piston engine 3340 using a temperature sensor, such as a thermocouple positioned in contact with or near a portion of the piston assembly (eg, near a piston face). In some cases, an increase in piston temperature can indicate insufficient cooling that can affect clearances. In another example, step 3506 may include detecting fluid in piston engine 3340 using a temperature sensor such as a thermocouple positioned in contact with the fluid or positioned near the fluid (eg, inserted into a fluid conduit with a suitable measurement port). (eg, the temperature of coolant, heating fluid, or exhaust that may be supplied to or exhausted from piston engine 3340 ). For example, in some cases, an increase in coolant temperature may indicate insufficient cooling that can affect the gap. In another example, step 3507 may include detecting piston engine pressure using a pressure sensor such as a piezoelectric transducer positioned in contact with the coolant or positioned near the coolant (eg, inserted into a pipe with a suitable measurement port). 3340 pressure of combustion section, gas drive section, gap, coolant, heating fluid, any other fluid, or any combination thereof. In another example, step 3508 may include detecting a piston engine using a force sensor and/or a temperature sensor, such as a piezoelectric transducer and/or a thermocouple positioned in contact with or near the interface of the component. Friction between components in 3340. In some cases, an increase in the effects of friction, such as frictional force or friction-generated heat, can indicate insufficient clearance. In another example, step 3509 may include detecting one or more properties of clearances in piston engine 3340 . The one or more properties may include the thickness of the gap (e.g., using a proximity sensor such as an inductive sensor), the asymmetry of the gap (e.g., using multiple proximity sensors such as an inductive sensor), the temperature of the blowby gas ( For example using a temperature sensor), the pressure of the blowby gas (eg using a pressure sensor), the composition of the blowby gas (eg using a gas sensor such as an optical waveguide absorption sensor), and other suitable properties or any combination thereof. In another example, step 3510 may include utilizing electromagnetic sensors (such as voltmeters, ammeters, or wattmeters), pressure transducers (such as to detect pressure for use in calculating mean effective pressure (MEP) such as indicating MEP, braking MEP, and and/or friction (MEP) or other suitable sensor detects the work interaction of the piston engine 3340 to provide an indication of clearance. In some cases, a decrease in work output or an increase in work input demand may indicate insufficient and/or excessive clearance.

Step 3512 may include processing device 3312 determining a control response based at least in part on any or all of the gap indicators detected in steps 3502 , 3504 , 3506 , 3508 , and 3510 . Processing device 3312 may receive sensor signals from sensor interface 3316 and perform one or more processing functions based on the sensor signals. Processing functions may include entering sensor signal values in formulas or other mathematical expressions, using sensor signal values in look-up tables or other databases, any other suitable processing, or combinations thereof. The processing device 3312 may determine a control response based on the output of one or more processing functions. For example, the calculated value may be compared to a predetermined threshold to determine an appropriate control response. In another example, one or more calculated values may be input into a control algorithm (eg, a PID control algorithm) and one or more control signal values may then be determined.

Step 3514 may include processing device 3312 providing a control signal to one or more auxiliary systems 3320 using control interface 3318 based at least in part on the control response determined in step 3512 . The control signal may be an analog signal, a digital signal, or a combination thereof (such as a combination of an analog signal and a digital timing signal), which may be provided as an electrical signal (such as with a cable), an electromagnetic signal (such as with an IEEE 802.11 "Wi-Fi" or Bluetooth receiver/transmitter), optical signals (eg using fiber optic cables), inductive signals (eg using suitable induction coils), or other suitable signal types.

In certain embodiments, the control signal in step 3514 may be received by one or more auxiliary systems 3320 that may adjust the clearance or other properties of piston engine 3340 . For example, as shown in step 3516, the control signal in step 3514 may be received by cooling/heating system 3322, which may regulate the temperature of the coolant or heating fluid. Cooling/heating system 3322 may include a thermostat or other temperature regulating device that may regulate the temperature of the coolant or heating fluid provided to piston engine 3340 at step 3516 in accordance with the control signal. In another example, step 3516 may include cooling/heating system 3322 adjusting one or more throttling properties to control throttling fluid temperature. In another example, the control signal in step 3514 may be received by cooling/heating system 3322, as shown in step 3518, which may regulate the flow rate of the coolant or heating fluid. Cooling/heating system 3322 may include a flow regulating device (eg, a metering valve or orifice) that may regulate the flow rate of coolant or heating fluid provided to piston engine 3340 at step 3518 in accordance with a control signal. In another example, step 3518 may include cooling/heating system 3322 adjusting one or more throttling properties to control throttling fluid flow rate. In another example, as shown in step 3520 , the control signal in step 3514 may be received by cooling/heating system 3322 , which may adjust the flow route of the coolant or heating fluid in step 3520 . Cooling/heating system 3322 may include one or more valves, throttles, or other flow control devices that may direct and control cooling provided to piston engine 3340 to and/or from one or more fluid passages in accordance with control signals flow rate of agent or heating fluid. In another example, as shown in step 3522, the control signal in step 3514 may be received by pressure control system 3324, which may adjust one or more properties of the heated tube at step 3522. Pressure control system 3324 may include one or more valves and a fluid reservoir, and may regulate fluid pressure within the heated tubes of piston engine 3340 in accordance with control signals (eg, by supplying fluid to or removing fluid from the heated tubes). In another example, as shown in step 3524, the control signal in step 3514 may be received by pressure control system 3324, which may regulate the pressure and / or traffic. The pressure control system 3324 may include one or more valves, pumps, and fluid containers, and may regulate the pressure and/or flow rate of the cylinder liner fluid in response to control signals (eg, by raising or lowering pressure in the cylinder liner passages), and respond accordingly Adjust the deformation of the deformable cylinder liner of the piston engine 3340 accurately. In another example, the control signal in step 3514 may be received by other systems 3328 , which may adjust one or more properties of piston engine 3340 , as shown in step 3526 . Other systems 3328 may include any suitable components for effectuating adjustment of one or more properties of piston engine 3340 at step 3526 based at least in part on the control signal. For example, other systems 3328 may include a power supply configured to provide power to one or more resistive heaters built into piston engine 3340, and step 3526 may include adjusting the voltage, current, or both of the above.

Any of the exemplary steps in flowcharts 3400-3500 may be combined with other steps, omitted, rearranged, or otherwise altered in accordance with the present disclosure.

The foregoing are merely exemplary illustrations of the principles of the disclosure, and various modifications can be made by those skilled in the art without departing from the scope of the disclosure. The foregoing examples are given for purposes of illustration and not limitation. The present disclosure may also take many forms other than what is expressly presented herein. Therefore, it is emphasized that the present disclosure is not limited to the expressly disclosed methods, systems and apparatuses, but that it should be understood to cover various modifications and variations of the present disclosure which fall within the spirit of the appended claims.

Claims (30)

CLAIMS 1. An assembly configured for translation along the axis of a cylinder bore of a cylinder of a piston engine, the assembly comprising: a piston face configured to contact a section of the cylinder capable of containing fluid; and At least one heating tube in direct or indirect thermal contact with the piston face. 2. The assembly of claim 1, wherein the first portion of the at least one heating tube and the piston face are configured to transfer heat therebetween, and wherein the second portion of the at least one heating tube The sections and thermal capacitors are configured to transfer heat between each other. 3. The assembly of claim 2, wherein the thermal capacitor includes at least one of a bearing element, a gap, a bore surface of a cylinder, and a piston rod. 4. The assembly of claim 1, further comprising a fluid contained within said at least one heated tube. 5. The assembly of claim 4, wherein the fluid comprises a fluid capable of undergoing a liquid/gas phase transition during operation of the piston engine. 6. The assembly of claim 4, wherein the fluid is selected from the group consisting of water, ethanol, ammonia, sodium, and any combination thereof. 7. The assembly of claim 4, wherein the at least one heating tube is capable of being sealed to maintain a constant volume of fluid contained within the at least one heating tube. 8. The assembly of claim 1, further comprising one or more fluid ports coupled to the at least one heating tube, wherein the fluid ports allow fluid to be supplied to or from the at least one heating tube Remove fluid from at least one heated tube. 9. The assembly of claim 1, wherein the at least one heating tube comprises at least one material selected from the group consisting of copper, aluminum, steel, stainless steel, nickel alloy, and bronze. 10. The assembly of claim 1, further comprising a piston frame, wherein the piston face is rigidly connected to the piston frame, and wherein the at least one heating tube is rigidly connected to the piston frame. 11. The assembly of claim 1, wherein the cylinder section includes at least one of a combustion section and a gas drive section. 12. The assembly of claim 1, further comprising at least one bearing element configured to provide flowing bearing fluid into a gap formed between the assembly and the cylinder. 13. The assembly of claim 12, wherein the bearing element is secured to the assembly, and wherein the assembly further comprises a transfer channel configured to receive bearing fluid from a fluid source and to the The bearing elements described above provide bearing fluid. 14. The assembly of claim 1, wherein the fluid contained in the cylinder section comprises a gas, and wherein blowby gas from the cylinder section passes from the cylinder section between the assembly and the cylinder The clearance axially flows away, and wherein the piston includes a feature or component that utilizes the flow of blowby gas to provide self-centering. 15. The assembly of claim 1, wherein the assembly is configured for oil-free operation. 16. A cylinder of a piston engine, said cylinder comprising: a cylinder having an axis configured to contain a piston moving along said axis; and At least one heating tube, the at least one heating tube is in direct or indirect thermal contact with the cylinder. 17. The cylinder of claim 16, wherein the first portion of the at least one heating tube and the cylinder barrel are configured to transfer heat therebetween, and wherein the second portion of the at least one heating tube The sections and thermal capacitors are configured to transfer heat between each other. 18. The cylinder of claim 17, further comprising one or more coolant passages, wherein said thermal capacitor includes coolant in said one or more coolant passages. 19. The cylinder of claim 16, further comprising a fluid contained within said at least one heated tube. 20. The cylinder of claim 19, wherein said fluid comprises a fluid capable of undergoing a liquid/gas phase transition during operation of said piston engine. 21. The cylinder of claim 19, wherein said fluid is selected from the group consisting of water, ethanol, ammonia, sodium, and any combination thereof. 22. The cylinder of claim 19, wherein said at least one heated tube is capable of being sealed to maintain a constant volume of fluid contained within said at least one heated tube. 23. The cylinder of claim 16, further comprising one or more fluid ports coupled to said at least one heated tube, wherein said fluid ports allow fluid to be supplied to said at least one heated tube or flow from said at least one heated tube Remove fluid from at least one heated tube. 24. The cylinder of claim 16, wherein said at least one heating tube comprises at least one material selected from the group consisting of copper, aluminum, steel, stainless steel, nickel alloy, and bronze. 25. The cylinder of claim 16, wherein said at least one heating tube is disposed around a central axis of said cylinder with a diameter greater than that of the cylinder. 26. The cylinder of claim 16, further comprising at least one bearing element configured to provide flowing bearing fluid into a gap formed between the piston and the cylinder. 27. The cylinder of claim 26, wherein the bearing element is fixed to the cylinder, and wherein the cylinder further comprises a delivery channel configured to receive bearing fluid from a fluid source and supply the bearing fluid to the cylinder. The bearing elements described above provide bearing fluid. 28. The cylinder of claim 26, wherein the bearing element is fixed to the piston, and wherein the piston further comprises a delivery channel configured to receive bearing fluid from a fluid source and supply the bearing fluid to the piston. The bearing elements described above provide bearing fluid. 29. The cylinder of claim 16, further comprising a cylinder section capable of containing a fluid, the fluid comprising a gas, wherein blowby gas from the cylinder section passes from the cylinder section through the piston and the cylinder The gap between them is axially flow-away, and wherein the piston includes a feature or component that utilizes the flow of blow-by gas to provide self-centering. 30. The cylinder of claim 16, wherein the cylinder is configured for oil-free operation.