NL2002283C2

NL2002283C2 - Internal combustion engine.

Info

Publication number: NL2002283C2
Application number: NL2002283A
Authority: NL
Inventors: Adriaan Lambertus Koop Vos
Original assignee: Var Motors Beheer B V
Priority date: 2008-12-03
Filing date: 2008-12-03
Publication date: 2010-06-07
Also published as: WO2010064898A1

Description

P29651NL00/ME

Title: Internal combustion engine

FIELD OF THE INVENTION

5 The invention relates to the field of internal combustion engines.

BACKGROUND OF THE INVENTION

Reference GB 616 944 discloses an internal combustion engine having a piston 10 reciprocating between a piston top dead center and a piston bottom dead center. The piston is slidably mounted in a sleeve. An interior of the sleeve and an outer (upper) end of the piston define a combustion chamber of variable size. The sleeve is arranged to reciprocate between a sleeve top dead center and a sleeve bottom dead center. The sleeve is slidably mounted in a cylinder. The movements of the piston and the sleeve are synchronized.

15 In the operation of the internal combustion engine disclosed in the reference GB 616 944, the piston reciprocating period is twice the sleeve reciprocating period, in other words, the sleeve reciprocating frequency is twice the piston reciprocating frequency. An ignition of an explosive fluid mixture (i.e. a mixture of one or more gasses and/or one or more liquids, e.g. in droplet form) is started when the volume of the combustion chamber is at or near its 20 minimum, the sleeve is at its sleeve bottom dead center, and the piston is halfway between the piston bottom dead center and the piston top dead center, moving towards the piston bottom dead center. In a next part of the operational cycle of the engine, during the combustion and the corresponding expansion of the ignited fluid mixture, the sleeve moves from its sleeve bottom dead center to its sleeve top dead center, while the piston further 25 moves to its piston bottom dead center, thus increasing the combustion chamber to its highest volume. In a next part of the operational cycle of the engine, in order to discharge the combustion gases from the combustion chamber, the combustion chamber is decreased to its lowest volume by moving the sleeve from its sleeve top dead center to the sleeve bottom dead center, while moving the piston from its piston bottom dead center to halfway between 30 the piston bottom dead center and the piston top dead center. In a next part of the operational cycle of the engine, the volume of the combustion chamber is increased again to charge it with a fresh explosive fluid mixture, by moving the sleeve from its sleeve bottom dead center to the sleeve top dead center, while moving the piston further to its piston top dead center. In a next part of the operational cycle of the engine, the volume of the combustion chamber, 35 now filled with the explosive fluid mixture, is decreased to its minimum by moving the sleeve -2- to its sleeve bottom dead center, and moving the piston from its piston top dead center to halfway between the piston top dead center and the piston bottom dead center. At this stage in the operational cycle of the engine, the explosive fluid mixture is ignited, starting the cycle as described above again.

5 A disadvantage of the internal combustion engine disclosed in the reference GB 616 944 is that the sleeve, having a relatively high mass relative to the mass of the piston, reciprocates at twice the frequency as the piston reciprocating frequency. This results in considerable energy losses due to inertia forces. Additionally, friction forces exerted on the sleeve are large due to its movement relative to both the piston and the cylinder.

10 A further disadvantage of the internal combustion engine disclosed in the reference GB 616 944 is that part of the operational cycle of the engine is used to remove the combustion gases from the combustion chamber, and subsequently another part of the operational cycle of the engine is used to charge the combustion chamber with a fresh explosive fluid mixture. Each of said parts of the operational cycle of the engine consumes 15 considerable energy, which cannot be delivered as driving power of the engine.

Another disadvantage of the internal combustion engine disclosed in the reference GB 616 944 is that the speed needs to be relatively high to obtain sufficient power, since in fact a four-stroke engine is disclosed.

20 SUMMARY OF THE INVENTION

It would be desirable to provide an internal combustion engine having improved efficiency. It would also be desirable to provide an internal combustion engine having a low combustion pressure. It would further be desirable to provide an internal combustion engine 25 being light-weight and/or small.

To better address one or more of these concerns, in an aspect of the invention an internal combustion engine is provided, comprising: a piston being arranged to reciprocate between a piston top dead center, PTDC, and a piston bottom dead center, PBDC; a sleeve in which the piston is slidably arranged, an interior of the sleeve and an end of the piston 30 defining a combustion chamber having a variable combustion chamber volume, the sleeve being arranged to reciprocate between a sleeve top dead center, STDC, and a sleeve bottom dead center, SBDC; and a cylinder in which the sleeve is slidably arranged. The movements of the piston and the sleeve are synchronized such that when the sleeve is at its SBDC, the piston is at its PBDC, and such that during a movement of the sleeve from the SBDC to the 35 STDC, the piston performs a reciprocating motion from the PBDC to the PTDC and back to the PBDC.

-3-

In the internal combustion engine according to the invention, the sleeve motion within an operational cycle of the engine is minimized, and thus energy losses in the engine are reduced, thus improving the efficiency of the engine and consequently reducing its cooling requirements at a predetermined output power.

5 When the combustion chamber volume is at its maximum, the combustion chamber can be washed by combustion gases being driven out of the combustion chamber by a fresh explosive fluid mixture. This obviates the need for a part of the operational cycle of the engine to be used for exhaust of combustion gases and intake of the fresh explosive fluid mixture.

These and other aspects of the invention will be more readily appreciated as the same 10 becomes better understood by reference to the following detailed description and considered in connection with the accompanying drawings in which like reference symbols designate like parts.

BRIEF DESCRIPTION OF THE DRAWINGS 15

Figure 1 schematically depicts an axial cross-section of an embodiment of an internal combustion engine according to the present invention, in a stage of operation.

Figure 2 schematically depicts an axial cross-section of the embodiment of the internal combustion engine of Figure 1, in another stage of operation.

20 Figure 3 schematically depicts an axial cross-section of the embodiment of the internal combustion engine of Figure 1, in still another stage of operation.

Figure 4 schematically depicts an axial cross-section of the embodiment of the internal combustion engine of Figure 1, in again another stage of operation.

Figure 5 shows a diagram indicating synchronized axial displacements of a piston and 25 a sleeve of an embodiment of an internal combustion engine according to the present invention.

Figure 6 shows a diagram indicating alternative synchronized axial displacements of a piston and a sleeve of an embodiment of an internal combustion engine according to the present invention.

30 Figure 7 illustrates an alternative actuator for a piston of an internal combustion engine according to the present invention.

Figure 8 illustrates a pressure diagram in a combustion chamber of an embodiment of an internal combustion engine according to the present invention.

Figure 9 shows a speed-torque diagram of an embodiment of an internal combustion 35 engine according to the present invention.

Figure 10 illustrates an inlet port, and an inlet port actuator, in an internal combustion engine according to the present invention.

-4-

Figure 11 illustrates a ignition plug arrangement in an internal combustion engine according to the present invention.

Figure 12 illustrates another ignition plug arrangement in an internal combustion engine according to the present invention.

5

DETAILED DESCRIPTION OF EMBODIMENTS

Figures 1-4 schematically show a cylinder 2 having an inlet port 4 (cylinder inlet port, CIP) and an outlet port 6 (cylinder exhaust port, CEP). The inlet port 4 is connected to a 10 supply of an explosive fluid mixture (not shown in Figure 1). The outlet port 6 is connected to an exhaust of combustion gases (not shown in Figure 1). In the cylinder 2, a cylindrical sleeve 8 is slidably arranged. Inside the cylinder 2, an inlet chamber 10 is defined by an end 8a of the sleeve 8 and the cylinder 2. The inlet chamber 10 has a variable volume due to the sleeve 8 being slidable in the cylinder 2. The (outer) side wall of the sleeve 8 is sealed in a gas-tight 15 manner relative to the (inner) wall of the cylinder 2. The sleeve 8 has an exhaust port 12 (sleeve exhaust port, SEP). In the sleeve 8, a piston 14 is slidably arranged. In the sleeve 8, a combustion chamber 16 is defined by an end 14a of the piston 14 and the sleeve 8.

In the embodiment of Figure 1, the sleeve 8 is hingedly coupled to a rod 18 at one end thereof. At another end, the rod 18 is rotatingly mounted to a crank 20 of a first crankshaft.

20 The piston 14 is hingedly coupled to a rod 22 at one end thereof. At another end, the rod 22 is rotatingly mounted to a crank 24 of a second crankshaft. Instead of one rod 18, also two parallel rods may be used to improve the stability of the movement of the sleeve 8, thereby to reduce friction of the piston in the sleeve 8, and to reduce friction of the sleeve 8 in the cylinder 2. The first and second crankshafts are coupled to each other by gears 26 and 28, 25 respectively, having a ratio of 2:1 (one revolution of gear 28 corresponds to two revolutions of gear 26). In Figures 1-4, directions of rotation of the gears 26,28 are indicated by arrows.

Instead of crank 24, the rod 22 can also be connected to an eccenter (not shown).

In said end 8a of the sleeve 8, a valve 30 in a sleeve inlet port, SIP, is provided which is normally in a closed position, and biased in such position by a biasing means such as a 30 spring. The valve 30 comprises an actuator rod 32.

Mechanical power resulting from a combustion process in the assembly of the cylinder 2, the sleeve 8, and the piston 14, is transmitted to the gears 26,28, where at least one of the gears 26, 28 may be coupled to a drive shaft of the internal combustion engine. In a practical embodiment, an internal combustion engine may comprise a plurality of assemblies, 35 depending on the power required for driving a load, and other requirements.

In the stage of operation shown in Figure 1, the piston 14 is near or at its piston top dead center, PTDC, while the sleeve 8 is about halfway between its sleeve bottom dead -5- center, SBDC and the sleeve top dead center, STDC, moving towards the STDC. In the combustion chamber 16, having a minimum volume, an explosive fluid mixture has been compressed, and is ignited by an igniter (not shown in Figure 1). In the inlet chamber 10, a fresh explosive fluid mixture is being compressed. As can be understood from Figure 1, after 5 the ignition of the fluid mixture, the end 8a of the sleeve 8 and the (end 14a of the) piston 14 will move away from each other, thereby increasing the volume of the combustion chamber 16 to a maximum volume, as shown in Figure 2.

In the stage of operation shown in Figure 2, the piston 14 is near or at its piston bottom dead center, PBDC, while the sleeve 8 is near or at its STDC. In this position of the 10 sleeve 8, the exhaust port 12 of the sleeve 8 overlaps the outlet port 6 of the cylinder 2, and combustion gases may flow out of the combustion chamber 16 through the outlet port 6. At the same time, the valve 30 is opened by an end of the actuator rod 32 contacting a head of the cylinder 2 to thereby open the valve 30. The opened valve 30 allows the compressed fresh explosive fluid mixture present in the inlet chamber 10 to flow into the combustion 15 chamber 16 to thereby press the combustion gases out of the combustion chamber 16 through the exhaust port 12 and the outlet port 6 (scavenging). Thus, the combustion gases are immediately replaced by a fresh explosive fluid mixture. By continued rotation of the gears 26,28, the volume of the combustion chamber 16 is decreases to a minimum volume, as shown in Figure 3.

20 In the stage of operation shown in Figure 3, the piston is near or at its PTDC, while the sleeve 8 is about halfway between its STDC and the SBDC, moving towards the SBDC. The explosive fluid mixture in the combustion chamber 16 is fully compressed. The valve 30 is closed. The inlet chamber 10 expands, thereby lowering the pressure in the inlet chamber 10. By continued rotation of the gears 26,28, the volume of the combustion chamber 16 stays 25 about the same, or is only slightly increased, relative to the volume shown in Figure 3, as is further shown in Figure 4.

In the stage of operation shown in Figure 4, the piston 14 is near or at its PBDC, and the sleeve 8 is near or at its SBDC. In this position of the sleeve 8, the inlet port 4 is opened, and fresh explosive fluid mixture may flow into the inlet chamber 10, the volume of which is 30 maximum. The valve 30 is closed. Upon continued rotation of the gears 26, 28, the volume of the combustion chamber 16 stays about the same, or is slightly decreased, relative to the volume shown in Figure 4, and the compressed fluid mixture will remain present in the combustion chamber 16.

Subsequently, the stage of operation shown in Figure 1 will be reached, and the 35 operational cycle of the internal combustion engine starts again.

-6-

Driving power generated by the engine may be provided at the crankshaft coupled to the crank 20 and/or the crankshaft coupled to crank 24. A flywheel (not shown) may be coupled to either one of the crankshafts coupled to the cranks 20,24.

Fig. 5 illustrates axial displacements of the sleeve end 8a and the piston end 14a in 5 the course of an operational cycle of the embodiment of the internal combustion engine as illustrated in Figures 1-4. Along the vertical axis, positions of the sleeve end 8a and the piston end 14a are represented. Along the horizontal axis, time t is represented. A vertical distance between a position of the sleeve end 8a at a particular point in time and a position of the piston end 14a at the same point in time is proportional to the volume of the combustion 10 chamber 16 at the point in time. Thus, the larger the distance, the larger the volume is. The point in time for the different positions of the sleeve 8 and the piston 14 shown in Figures 1-4 are indicated in Figure 5 by (l)-(IV), respectively, along the horizontal axis. In Figure 5, a point in time for ignition of the explosive fluid mixture is indicated with a lightning symbol, which ignition point in time may be varied between point in time (I) (as indicated in relation to Figure 15 1) or an earlier point in time, as illustrated in Figure 5 by a double arrow.

Figure 6 illustrates axial displacements of the sleeve end 8a and the piston end 14a in an embodiment of the internal combustion engine in which the displacement of the piston 14 is modified when compared to the displacement of the piston 14 according to Figures 1-5. In the embodiment according to Figure 6, the piston 14 is actuated differently when compared to 20 the crank 24, and gear 28, as is explained in further detail below with reference to Figure 7. The piston 14, after having reached its PBDC after an ignition of the explosive fluid mixture (the sleeve 8 being in its STDC), rests in its PBDC until the sleeve 8 has reached its SBDC, and after that performs the same reciprocating action as in Figure 5. Thus, the fresh explosive fluid mixture having entered the combustion chamber 16 when the sleeve is in its STDC, is 25 subsequently compressed very gradually.

In Figure 6, alternative displacements of the piston 14 in time are indicated with dashed lines 14a1 and 14a2. According to line 14a1, the piston end 14a is moved from its PTDC to the PBDC more gradually than shown in Figure 6 by the solid line in the same time period. Hence, the piston 14 has not yet reached its PBDC when the sleeve reaches its 30 STDC, the combustion chamber volume has not yet reached its maximum volume when the sleeve reaches its STDC, and the timing of the removal of the combustion gases from the combustion chamber and the inlet of the fresh explosive fluid mixture into the combustion chamber may be delayed until after the sleeve reaches its STDC. According to line 14a2, the piston end 14a is moved from its PTDC to the PBDC less gradually than shown in Figure 6 by 35 a solid line in the same time period. Hence, the piston 14 has already reached its PBDC before the sleeve reaches its STDC.

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Figure 7 illustrates by way of example a cam actuator for imposing a reciprocating action as illustrated in Figure 6 on the piston 14. The cam actuator will replace the crank 24 and gear 28 as illustrated in Figures 1-4. In Figure 7, the rod 22 connected to the piston 14 is guided in a guide 90 allowing only a movement of the 22 in a reciprocating way, as indicated 5 by double arrow 92. The rod 22 is provided with a stop 94. A spring 96 connected directly or indirectly to the cylinder 2 presses the rod 22 against a rotating cam 98 through a force exerted on the stop 94. The cam 98 is arranged to rotate around an axis/shaft 99 in the same period as the period of the sleeve 8 or, in other words, the cam 98 will make one revolution when the gear 26 makes one revolution. The profile of the cam 98 can be changed to provide 10 a reciprocating action on the piston 14 to have piston end 14a to move in accordance with displacement lines 14a1 or 14a2 (Figure 6), or any other desired displacement in time.

By way of example, Figure 8 shows a diagram of the pressure in the combustion chamber 16. Along the vertical axis, a pressure P is indicated. Along the horizontal axis, the position of the sleeve 8 is indicated by reference to the STDC and the SBDC, and to the 15 different stages (l)-(IV) in the operational cycle of the engine, referring to Figure 5. The pressure P curve between stages (I) and (II) represents the engine running at no-load. When the engine is loaded, the curve may be like dashed line 80, while at no-ignition, the curve may be like dashed line 82.

According to the invention, the (combustion) pressure in the internal combustion 20 engine can be low, since the combustion takes place when the position of the crankshaft coupled to the sleeve 8 is about at right angles to the direction of reciprocation of the sleeve 8. Here, a torque generation is at an optimum. Applying a relatively low combustion pressure, the materials used for fabrication of the parts transmitting forces in the engine may be chosen to have less strength. The engine may be constructed smaller and/or lighter in weight.

25 Cooling requirements of the engine may be modest.

Figure 9 shows a speed-torque diagram. Along the vertical axis, a torque T is indicated. Along the horizontal axis, a speed S (rev/min) is indicated. Figure 9 illustrates a flat curve (dashed line) above a relatively low speed of e.g. 800 rev/min. Thus, the internal combustion engine according to the present invention will deliver an almost constant torque 30 over a wide range of speed.

Figure 10 shows a sleeve inlet valve, SIV, 30 in an opening of the sleeve 8. The valve 30 is kept in a closed position by a biased spring 34 provided between the sleeve 8 and a stop 36 on valve rod 32. A stop 38 of which the axial position can be set, is provided in the cylinder 2. When the sleeve 8 moves towards the stop 38, at a predetermined position of the 35 sleeve 8 relative to the cylinder 2, the stop 36 will contact the end of the stop 38 facing the stop 36. Upon further movement of the sleeve 8, the valve 30 will be opened, thereby establishing a communication between the inlet chamber 10 and the combustion chamber 16, -8- as also illustrated in Figure 2 in another embodiment. The end of the stop 38 facing the stop 36 may have such transverse dimensions that differences in transverse positions of the stop 36 during operation of the engine still lead to a reliable actuation of the stop 36 by the stop 38.

5 Figure 11 shows an ignition plug 40 mounted on the sleeve 8 such that the ignition plug 40 can ignite a explosive fluid mixture in the combustion chamber 16. The ignition plug has an elongated electrical contact 42 being movable relative to, and in electrical contact with, an electrical counter contact 44 being mounted in the cylinder 2 in an isolator 46. Together, the contact 42 and the counter contact 44 form a brush contact. An appropriate 10 voltage applied to the counter contact 44, as indicated by the lightning symbol, will generate a spark in the combustion chamber 16. The contacts 42, 44 are enclosed in an insulating structure to prevent any sparking in the brush contact to unintendedly ignite an explosive fluid mixture in the inlet chamber 10. Instead of the brush contact, an electrically conducting spring can be used to establish an electrical connection to the ignition plug 40 from outside the 15 cylinder 2.

The sleeve inlet valve 30 may be placed concentrically on the sleeve end 8a as shown in Figure 10, or eccentrically, as desired. Likewise, the ignition plug and its contacts 42, 44 may be placed eccentrically on the sleeve end 8a as shown in Figure 11, or concentrically. Taking into account a sensitivity of the arrangements 20 Figure 12 shows an alternative arrangement of an ignition plug 40. The plug is mounted on the cylinder 2 in an opening 50 thereof to the inlet chamber 10/sleeve 8. The sleeve 8 is provided with an opening 52. When the openings 50 and 52 overlap, a spark created with the ignition plug 40 by applying an appropriate voltage to the ignition plug 40 (as indicated by the lightning symbol) may ignite an explosive fluid mixture in the combustion 25 chamber 16.

In a practical embodiment, the ratio of the maximum volumes of the inlet chamber and the combustion chamber is greater than two, in particular greater than four, an more in particular about five.

The internal combustion engine according to the present invention may consume 30 different kinds of fuels, like normal petrol of different octane content such as the well known Euro 91, Euro 95 or Euro 98 petrol, and other fuels like E85, LPG, methane gas and hydrogen gas.

Summarizing, an internal combustion engine has a piston reciprocating between a piston top dead center, PTDC, and a piston bottom dead center, PBDC. The piston is slidably 35 arranged in a sleeve which reciprocates between a sleeve top dead center, STDC, and a sleeve bottom dead center, SBDC. The sleeve is slidably arranged in a cylinder. The sleeve reciprocates with a period which is twice as long as the period in which the piston -9- reciprocates. During a movement of the sleeve from the SBDC to the STDC, the piston performs a reciprocating motion from the PBDC to the PTDC and back to the PBDC, and during a movement of the sleeve from the STDC to the SBDC, the piston again performs a reciprocating motion from the PBDC to the PTDC and back to the PBDC, or the piston 5 remains stationary at its PBDC.

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis 10 for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description of the invention.

The terms "a" or "an", as used herein, are defined as one or more than one. The term 15 plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language, not excluding other elements or steps). Any reference signs in the claims should not be construed as limiting the scope of the claims or the invention.

20 The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically.

The invention has one or more of the features which are described in the following 25 clauses: 1. An internal combustion engine, comprising: a piston arranged to reciprocate between a piston top dead center, PTDC, and a piston bottom dead center, PBDC; a sleeve in which the piston is slidably arranged, an interior of the sleeve and an end of 30 the piston defining a combustion chamber having a variable combustion chamber volume, the sleeve being arranged to reciprocate between a sleeve top dead center, STDC, and a sleeve bottom dead center, SBDC; and a cylinder in which the sleeve is slidably arranged, wherein the movements of the piston and the sleeve are synchronized such that: 35 - when the sleeve is at its SBDC, the piston is at its PBDC, and - during a movement of the sleeve from the SBDC to the STDC, the piston performs a reciprocating motion from the PBDC to the PTDC and back to the PBDC.

-10- 2. The internal combustion engine of clause 1, wherein an explosive fluid mixture in the combustion chamber is ignited when the piston is near or at its PTDC, and the sleeve is moving from the SBDC to the STDC.

3. The internal combustion engine of clause 1 or 2, wherein the combustion chamber 5 volume is near or at a minimum when the sleeve is at its SBDC.

4. The internal combustion engine of any preceding clause, wherein the piston is movable such that the combustion chamber volume at the PBDC, when the sleeve is at its SBDC, is about the same as the combustion chamber volume at the PTDC.

5. The internal combustion engine of any preceding clause, wherein the piston is movable 10 such that the combustion chamber volume at the PBDC, when the sleeve is at its SBDC, remains about the same during a subsequent movement of the piston to the PTDC.

6. The internal combustion engine of any preceding clause, wherein the piston is at its PBDC when the sleeve is near or at its STDC.

7. The internal combustion engine of any preceding clause, wherein, during a movement 15 of the sleeve from the STDC to the SBDC, the piston performs a reciprocating motion from the PBDC to the PTDC and back to the PBDC.

8. The internal combustion engine of any of clauses 1-6, wherein, during a movement of the sleeve from the STDC to the SBDC, the piston remains stationary at its PBDC.

9. The internal combustion engine of any preceding clause, wherein the sleeve 20 reciprocates with a sleeve reciprocating period, and the piston reciprocates with a piston reciprocating period, wherein the sleeve reciprocating period is longer than the piston reciprocating period.

10. The internal combustion engine of clause 9, wherein the sleeve reciprocating period is at least two times as long as the piston reciprocating period, in particular at least three times.

25 11. The internal combustion engine of any preceding clause, wherein the sleeve has a sleeve exhaust port, SEP, and the cylinder has a cylinder exhaust port, CEP, and wherein the SEP overlaps the CEP when the sleeve is near or at its STDC.

12. The internal combustion engine of clause 11, wherein the SEP overlaps the CEP when the piston is near or at its PBDC.

30 13. The internal combustion engine of clause 11 or 12, wherein the sleeve closes the CEP

when the sleeve is not near or at its STDC.

14. The internal combustion engine of any preceding clause, wherein an interior of the cylinder and an end of the sleeve define an inlet chamber, wherein the cylinder has a cylinder inlet port, CIP, and wherein the CIP is in open communication with the inlet chamber when 35 the sleeve is near or at its SBDC.

15. The internal combustion engine of clause 14, wherein the sleeve closes the CIP when the sleeve is not near or at its SBDC.

-11 - 16. The internal combustion engine of any preceding clause, wherein an interior of the cylinder and an end of the sleeve define an inlet chamber, wherein the sleeve has a sleeve inlet valve, SIV, and wherein the SIV is in open communication with the inlet chamber when the sleeve is near or at its STDC.

5 17. The internal combustion engine of clause 16, wherein the SIV is arranged to be opened by a stop, in particular an adjustable stop, mounted in the inlet chamber.

18. The internal combustion engine of any preceding clause, wherein the sleeve carries a ignition plug for igniting the explosive fluid mixture in the combustion chamber, the ignition plug being energized through an electrical wiper having a stationary part connected to the 10 cylinder, and a movable part connected to the ignition plug.

19. The internal combustion engine of any preceding clause, wherein the sleeve is coupled to a sleeve crankshaft defining the reciprocating motion of the sleeve.

20. The internal combustion engine of clause 19, wherein the piston is coupled to a piston crankshaft or an eccentric shaft defining the reciprocating motion of the piston.

15 21. The internal combustion engine of clause 19, wherein the piston is coupled to a piston cam mounted on a rotatable shaft, the piston cam defining the reciprocating motion of the piston.

22. The internal combustion engine of clause 14, wherein the ratio of the maximum volumes of the inlet chamber and the combustion chamber is greater than two, in particular 20 greater than four, and more in particular about five.

Claims

An internal combustion engine, comprising: a piston reciprocally arranged between an upper dead end of the piston, PTDC, and a lower dead end of the piston, PBDC; a canister in which the piston is slidably mounted, an interior of the canister and an end of the piston defining a combustion chamber with a variable combustion chamber volume, the canister being movably reciprocated between an upper dead end of the canister, STDC, and a lower death point of the bus, SBDC; and a cylinder in which the sleeve is slidably mounted, the movements of the piston and the sleeve being synchronized such that: - when the sleeve is in its SBDC, the piston is in its PBDC; and - during a movement of the bus from the SBDC to the STDC, the bus performs a reciprocating movement from the PBDC to the PTDC and back to the PBDC.

The internal combustion engine of claim 1, wherein an explosive fluid mixture is ignited in the combustion chamber when the piston is in its

The internal combustion engine according to claim 1 or 2, wherein the combustion chamber volume is near or to a minimum when the canister is on its SBDC. 25

The internal combustion engine according to any preceding claim, wherein the piston is movable such that the combustion chamber volume at the PBDC, when the canister is at its SBDC, is approximately the same as the combustion chamber volume at the PTDC.

The internal combustion engine according to any preceding claim, wherein the piston is movable such that the combustion chamber volume at the PBDC, when the bushing is at its SBDC, remains approximately the same during a subsequent movement of the piston to the PTDC.

The internal combustion engine according to any preceding claim, wherein the piston is on its PBDC when the sleeve is near or on its STDC. -13-

The internal combustion engine of any preceding claim, wherein, during a movement of the bus from the STDC to the SBDC, the piston performs a reciprocating movement from the PBDC to the PTDC and back to the PBDC.

The internal combustion engine according to any of claims 1-6, wherein, during a movement of the bus from the STDC to the SBDC, the piston remains stationary at its PBDC.

9. The internal combustion engine according to any preceding claim, wherein the sleeve is arranged to move back and forth with a reciprocating period of the sleeve, and the piston is arranged to move back and forth with a reciprocating piston playback period, wherein the reciprocating period of the sleeve is longer than the reciprocating period of the piston.

The internal combustion engine according to claim 9, wherein the reciprocating period of the can is at least twice as long, in particular at least three times as long, as the reciprocating period of the piston.

11. The internal combustion engine of any preceding claim, wherein the bus has a bus outlet port, SEP, and the cylinder has a cylinder outlet port, CEP, and wherein the SEP overlaps the CEP when the bus is near or in its STDC.

The internal combustion engine of claim 11, wherein the SEP overlaps the CEP when the piston is near or in its PBDC. 25

The internal combustion engine according to claim 11 or 12, wherein the bus closes the CEP when the bus is not near or on its STDC.

14. The internal combustion engine according to any preceding claim, wherein an interior of the cylinder and an end of the sleeve define an inlet chamber, the cylinder having a cylinder inlet port, CIP, and wherein the CIP is in open communication with the inlet chamber when the bus is near or on its SBDC.

The internal combustion engine of claim 14, wherein the bus closes the CIP when the bus is not near or on its SBDC. -14-

The internal combustion engine of any preceding claim, wherein an interior of the cylinder and an end of the canister define an inlet chamber, wherein the canister has a canister inlet valve, SIV, and wherein the SIV is in open communication with the inlet chamber when the bus is near or on its STDC. 5

The internal combustion engine according to claim 16, wherein the SIV is adapted to be opened by a stop, in particular an adjustable stop, arranged in the inlet chamber.

The internal combustion engine according to any preceding claim, wherein the bush carries a spark plug for igniting the explosive fluid mixture in the ignition chamber, the spark plug being fed via an electrical sliding contact to a stationary part connected to the cylinder, and a movable member connected to the spark plug. 15

The internal combustion engine according to any preceding claim, wherein the bushing is coupled to a bushing crankshaft defining the reciprocating movement of the bushing.

The internal combustion engine of claim 19, wherein the piston is coupled to a piston crankshaft or an eccentric shaft that defines the reciprocating movement of the piston.

20 PTDC, and the bus moves from the SBDC to the STDC.

21. The internal combustion engine of claim 19, wherein the piston is coupled to a piston comb mounted on a rotatable shaft, the piston comb defining the reciprocating movement of the piston.

22. The internal combustion engine of claim 14, wherein the ratio of the maximum volumes of the inlet chamber and the combustion chamber is greater than two, in particular greater than four, and more particularly approximately five.