US2272171A - Internal combustion engine - Google Patents

Description

Feb. 10, 1942. w. HARPER, JR

INTERNAL` COMBUSTION ENGINE Filed March 27, 1959 sheets-snee# 1 ATTORNE Feb. l0, 1942. w. HARPER, JR

INTERNAL cMBUsTIoN ENGINE Filed March 2'7, 1939 6 Sheets-Sheet 2 ATTORNE Feb; 10, 11442.` w. HARPER, JR

INTERNAL COMBUSTION ENGINE` Filed Mar-0h27, 1939 6 Sheets-Sheet 5 ATTORNY Feb. 10, 1942. w. HARPER,'JR 2,272,171

' INTERNAL coMBUs'TIoN ENGINE Y Filed March 27, 1939 6 Sheets-Sheet 4 INVENTOR /W/a/w /wf/ a ATTOR Y y? my@ "TT, mh

Feb. 10, 1942.

w. HARPER, JR

INTERNAL COMBUSTION ENGINE Filed March 27, 1939 6 sheets-sheet 5 ATTO R EY Feb. 10, 1942. \w. HARPER, JR

` INTERNAL COMBUSTION` ENGINE Filed March 27, 1939 I 6 sheets-sheet e INVENTOR Ufa/7545,05; Je. BY

lATTOFQN Y Patentedreb'. 1o, 1942 s PATENT OFFICE INTERNAL coMUsTIoN ENGINE William Harper, Jr., Montreal, Quebec, Canada Appliation Marca '21, 1939, serial No. 264,462

16 claims.' (ci. 12s- 65) This invention relates to internal combustion engines and aims to provide improvements in the valve mechanism for internal combustion engines.

This application is a continuation in part of my co-pending application filed March 27, 1936, Serial No.'71,l17, now Patent Number 2,151,698, dated March 28, 1939.

A particular object of' the present invention is the provision of valve mechanism adapted for use ,in a heavy-oil-burning engine whose ratio. of

.weight to power is suiiiciently low, and whose Aspeed of operation is sufficiently high, to make it available for airplane use. y

It is essential in heavy-oil-burning internal combustion engines, particularly those of the twocycle'type in located in the cylinder head,

which the exhaust valve ports are that the area of illustrated in lthe accompanying drawings.. The drawings show, for the'sake of illustration, an eight-cylinder heavy-oil-burning engine of the 'opposed cylinder, two-cycle type embodying the invention:

Fig. 1 is a side elevation ofthe engine;

Fig. 2 is a vertical section on the axis of one of the pairs of opposed cylinders taken on the line 2-2 of Fig. 1;

Figs. 3, 4 and 5 are diagrammatic illustrations of the different positions assumed by the rotary. ram outletvalve;

Fig. 6 is an enlarged section valve shown inv Fig. 2;

of the solenoid Fig. 7 is an enlarged section of one of the cyl-k inders taken on the same plane as Fig. 2;

those ports be as large as the diameter of the cylinder will permit. Past attempts to supply lsuch exhaust ports of .the necessary area have entailed the use of expensive valve mechanism which was so heavy and cumbersome that it has been impossible to attain the rapidity of opera-v tion of the valve mechanism which is essential to high-speedv operation of the engine.

Further difficulties have arisen from inability to attain the required speed of operation and acceleration of the valves without such very steep cams that the violence of their action has caused showing the valve-operating mechanism;

the valves to chatter and from inability to provide for the adequate lubrication o f the valve mechanism. i

The valve mechanism which I have invented avoids the foregoing difficulties and providesan inexpensive, light, compact, symmetrical assem-` bly which provides high volumetric eiiicincy and permits excellent combustion chamber design and in which the lines .of stressl are straight and there is no wide variation in the temperature gradients 'of the assembly during operation. Other objects and advantages of my invention will be apparent from the following description of a speciic embodiment thereof.

In accordance with my invention, the cylinder y head of an internal combustion engine is provided with a plurality of ports, each of which is The valves are operated provided with a valve. by mechanism which is actuated by a cam rmember mounted in the cylinder head casing for rotation about the axis of the cylinder.

The nature of'my invention may best be un-` derstood from a detailed description of the construction and operation of a practical internal combustion engine embodying the invention .and

' connects the cylinders.- vided with water jackets I2 whose emciency is in- Fig..8 is an enlarged section of one of the cylinders taken on the opposite plane from Fig. '1; Fig. 9 is a fragmentary view showing a valve cam and means for operating it; Fig. 10 is a section on the line IIJ-I0 of Fig. 7

Fig. 11 is asection on the line I I-II of Fig.` 8; Fig. 12 is a fragmentary view of the mechanism for transmitting rotation fromrthe drive shaft to the shaft actuating the exhaust valves;

. Figs. 13 and 14 are fragmentary views showing the gear train which operates the ram outlet valve; and Fig. 15 is a timing diagram of the engine.-

The engine illustrated has four pairs of opposed cylinders ID. Y The inner ends of each pair of cylinders I0 open into a crank case II which The cylinders are procreased by the spiral baliles I3 contained. in them.

y With each pair of cylinders and.y its crank case are associated A means for supplying air to the crank case, B means 'for by-passing vair around the pistons from the crank case to the cylinders,

, C a main fuel supply, D means for firing the fuel rand air mixture, E means for utilizing a part of the exhaust fumes to increase the pressure of the air in the crank case, and F means for eX- hausting the main body of burnt gases from 'the cylinders.

The -means for supplying air to each crank. case II includes a blower AI, which maybe directly connected to the main shaft of the engine and which forces air, under a pressure of approximately three pounds per square inch through an inlet manifold A2 to rotary inlet valves A3 whichcontrol the admission, at the propertime, of air to the crank case. Inlet valve A3 is xed to lshaft A8 which s-rotated from drive shaft i4. VA spur gear, AQ, xed to the shaft A8 meshes with spur gear A5 attached to end of its stroke, as illustrated in Fig. 2F, the

ports B5 in the skirt of the piston register with ports in the cylinder wall which are connected by spiral external conduits B8 to diametrically opposite sets of air entrance ports B9 in the Wall of the cylinder. The entrance ports B9 are'positioned so that they areluncovered by the front end of the piston when the piston is at the inner end of its stroke. The front end of the piston is preferably provided with a co'ncave surface l1 which causes air admitted from the crank case through the ports B9 to advance through cylinder I0 in a flat-topped column during the compression stroke of the piston l5.

The fuel supply means, the firing means and from transverse shaft 30, so that it makes one complete revolution with each revolution of the engine shaft I4, but at varying speeds:

Transverse shaft 30, extending across casing and journalled in its side walls,- is driven from the drive shaft I4 at speeds which correspond with those of the drive shaft. The shaft 3 0 for one bank of cylinders isconnected through miter gears 3l' with the upper end 32 of a crossshaft whose lower end 33 is connected-through miter gears 34 with spur gear A5 driven from the engine shaft I4 as aforesaid. The crossshaft 3D for the other bank of'cylinde'rs is connected through miter gears 3|' with the upper end 32 of a cross-shaft whose lower end 33' is likewise connected with spur gear A5. In order that the upper ends l32, 32' of the cross-shafts will rotate in the same direction, the upper end `32 is connected with the lower end 33 through' a pair of spurgears 35.

The rotation of transverse shaft is transmitted to spur gear E8 which is in mesh with spur gear E9 fixed to shaft EN. Elliptic gear EH keyed to shaft EIO meshes with elliptic gear the valve mechanism for each cylinder is lo- Y cated in a casing 20 at the head of the cylinder. f This casing consists of a casting 2l`, which may be made integral with the cylinder head 22 as shown, and a cover 23 closing the outer end of the casting 2l. The inner surface 24 of the' cylinder head is preferably concave like the surface I'I of the piston. l

The main fuel supply means includes an infront jector CI located in the casing 20, with its'innerv end secured in a central opening C2 in the cylinder head 22, so that its nozzle C3 is directed axially into the cylinder. The injector CI is of the conventional type used for the injection of heavy fuels into the cylinders of Diesel engines, and is, therefore, not described in detail. Fuel is supplied to it through a pipe C4 from a pump, not shown, which is driven from the main shaft of the engine'and timed by the means customar- Fl, Fl,

ily used with such fuel iniectors in Diesel engines.

chamber DI from the crank case Il, throughl a conduit D4, controlled by an inlet valve D5, located in the casing 20. A light fuel is supplied to the primary combustion chamber DI through an injector D6 -of conventional construction, to

which the fuel is supplied by a conventional pump and timing device. Spark plugs D1 are provided to ignite the' mixture in the primary combustion chamber DI. Conventional means for i supplying electricity and timing the spark are connected with these spark plugs.

The means for utilizing a part of the exhaust for increasing the pressure in the crank case y includesv ram conduits El,connecting the crank case H with two small `high-pressure exhaust ports E2 in the cylinder head (Figs. 9 and 10).

The ports E2 are controlled by valves E3. Exhaust or scavenging ports E4 are provided in the ram conduits El near the ends of these conduits which enter the cylinder head and are controlled by rotary valves E5, each of which is operated by its individual shaft E6, driven Ell keyed to shaft EI2. The varying speeds of rotation of shaft EI2 occasioned by elliptic gears El I and El i' are transmitted through spur gears EI3, EI4 and E|5 to the shaft E8 upon which rotary valve E5 is mounted.

The ram conduits El may be closed, if desired.

by a manually operated grid valve EIB which is provided at the ends of those conduits which enter cranl'. case I'I 'I'he main exhaust from the cylinder is through three large 'ports FI.` Fl, FI in the cylinder' head, connected through passages F2 in the casting 2|, with the exhaust manifold F3. The ports FI' are controlled respectively by the main exhaust valves F4, F4, F4.`

Valve control vmechanism for operating the high pressure exhaust valves E3, the main exhaust valves F4, F4, F4' and the inlet valve D5 of the primary combustion chamber DI is contained in theV casing 20 and is also driven by the transverse shaft 3l). The shaft 30 carries a worm 31 which meshes with gear 38 Journalled on a sleeve 39fsurroundi'ng the fuel injector Cl and supported by anti-friction bearings 40. The cam member 4I is mounted upon gear 38 for rotation therewith, and the gearing is such that the cam member is rotatedat one-half `the speed of rotation of the engine shaft; On the upper surface of the cam member 4| are two concentric pairs of cams with the cams of each pair spaced apart. The cams DF4| of the outer series control the inlet valve D5 and the main exhaust valves F4, F4, F4'. The camsE4I of the inner vseries control the high-pressure exhaust valves fulcrum-bearing' disc 43 with a central opening surrounds the sleeve 39 and the injector CI, and is secured in an opening at the top of an inner wall 44 in the casting 2|.- This disc contains `vertical bores in which are mounted plungers DF45, each of which bears rollersDF46 in position to be engaged by cams DF4I. The plungers DF45 are connected through knuckles DF" with adjustable bearings F48 screwed in the inner ends of rocker arms F49, whose outer ends engage the stems of the main exhaust valves F4, F4.

'I'he stem of the main exhaust valve F4' is engaged by the outer end of a forked telescoping lever F49', whose inner ends are connected through the knuckles DFH and adjustable bearings F4E with the inner ends of the rocker arms vDF4I by an F49. The inlet valve D5 is actuated by forked rocker arm D49, whose inner ends rest upon the adjustable bearings F48', and whose outer end is provided with an adjustable member D41 adapted to engage and depress plunger D50, which rests upon the stem of inlet valve D5.

The inlet valve D3 and the main exhaust valves F4, F4, F4 are thus actuated by a' balanced set of rocker arms and, as illustrated in Figs. and 11, the valve mechanism is symmetrically arranged about thel axis of the cylinder.,

A limited tipping movement is permitted' the inner, forked ends of the rocker arms F49' and D49 to compensate automatically for any inequalities in the adjustments of the members F48, F48 and D48. rlhis is accomplished in the telescoping rocker arm F49 by providing the inner forked portion F5I' with slot F52' through which the pin F53 extends so that theforked portion F5I' ball bearing D56.

gaged by either of the cams E4I. The plungers i E45 are connected by adjustable member E48 with the inner ends of rocker arms E49. The outer ends of rocker arms E49 rest upon the inner ends of levers E60 which bear upon the stems of the high-pressure exhaust valves E3 and whose ends are pivoted to theinner wall 44 of casting 2 I. The high-pressure exhaust valves E3 are thus actuated'by compound levers whichv cause the opening of those valves to be accelerated very rapidly when plunger E45 is raised by one of the cams E4I. l

As shown in Fig. 9, the ca'm member 4I rotates in a counterclockwise direction and the leading edges of the cams E4I are spaced respectively outer from the leading edges-of the following cams angle greater than-90 so that the roller E46, which is symmetrically spaced by angles of 90 from the rollers DF46, will open the high-pressure exhaust valves E3 .in advance of the opening of the main exhaust valves F4, F4, F4'.

and the top of plunger D when the main exhaust valves are closed so that the inlet valve D5 is not opened until after the main exhaust Y valves F4, F4, F4 have been opened.

The transverse shaft 30 of the valve. mechanism terminates a short distance outside of the walls of the cylinder head casing 28 ofeach cylinder. The shafts 30 ofl the adjoining cylinders in the respective banks are joined by removablecouplings 6I and the miter gears-3|, 3l" are readily separated. The valve-actuating mechanism for each cylinder is thus a complete unit which may be removed with the head of that cylinder and without disturbing the adjustments of the various valves by merely removing the couplings 6I or separating the mitcr gears 3I or 3l at the ends ofthe cross-shaft 30 of that cylinder.

The valve mechanism is lubricated by oil which are shown in the drawings,

through an annular channel'65 formed in the inner wall 44 of casting 2|. From the channel 65 the oil flows through passages l64, some of which to all of the bearings of the valve mechanism. After the oil has .passed through the bearings, it flows to the bottom of the lowest part of the casing 20 and is then withdrawn through an outlet conduit 63.

Manually operated means are provided for relieving the compression in e`ach cylinder when desired: Rocker arm F49' is provided at its outer end F54' with a finger F62. A plunger F63' is connected` by a link F64 lwith a lever F65 pro jecting outside the casing 23. Manual 'operation of the lever F65 occasions rotation of the plunger F63v causing the cam F66 to be forced out of the dwell in sleeve' F61', thus forcing plunger F53" and the outer end of rocker arm F49' downward and opening valve F4'.

To start the engine, compressed air is forced through check valves 69 .into those Qylinders I8 whose pistons I5 are in positionto make .a power stroke. In order that the proper pistons may be V supplied withcompressed air at appropriate times, theflow of air toeach pair of pistons is controlled by a. solenoidlvalve J0 connected by T fitting 1I with a conduit 12 which communicates with the inlet port of check valves 69 of 'opposed cylinders.

Normally the solenoid valve 10 is held in closedposition as illustrated in- Fig. 6 by thevsprng 14. When current is supplied 'to the coil 16 the core` is pulled inwardly pivoting lever 11 to raise plunger 18 and depress plunger 19. Air is forced by a conventional compressorv (not shown), connected with solenoid valve 10 by pipe 80, through passageway 8|, which is then open, and passageway 82 to the interior of cylinder 83, depressing piston 8 4 and opening port 85. The compressed air then ows through' port 85 and check valve 69 to the cylinder ISI where it forces piston I5 inwardly. As piston `I5 ends itsinstroke, the supply of current to coil 16 is cut off and spring 415 causes lever 11y to be pivoted so that plunger 18 closes passageway 8I and plunger 19 opens passageway 81 through which the compressed air in cylinder 83 escapes.. Conventional timing means for supplying electricity'to coils 16 at appropriate times are connectedwith those coils.

The operation of the "engine which has been described may best be understood from the timing diagram Fig. 15, which indicates by shading .A clearance is provided between the member D41 lil.'

the approximate periods during each revolution of drive yshaft I4 at which the various ports and valves are open. The right-hand side of the diagram represents the outstroke of the piston, thatA is, the strokevin which the piston moves away from the cylinder head, while the left-hand side represents therinstroke.

rst part ofthe out or power stroke of piston I5,

air is supplied from ythe compressor AI to crank case I I through inlet valve A3 until a pressure of approximately 3-pounds per square inch is atis supplied from a conventional pump (not` tained. in the crank cese. This pressure 'is increased as the pistons approach each other during the balance of the' outstroke, and it is built up to a very considerable pressure, for example,

15 pounds per square inch' as follows: During'the power stroke of inletyalves E5 arebin the position illustrated in Fig. 3. At the end of the power stroke, the highpressure exhaust valves AE3 are opened. thus forcing exhaust gases under-very high pressure into theram conduits El. AIn order that these ex- During the latter part of the instroke and the the piston I5, the vram conduitv haust gases shall not reach the crank case, the

rotary movement of valve E is suddenly accelera-ted by the action of elliptical gears EI I, EI I', so that the valve E5 assumes the position illustrated in Fig.r2, in which exhaust gases from the high-pressure exhaust port pass out through the exhaust outlet E4, thus providing super-charging through the high-pressure exhaust gas without contaminating the air in the crank case or reducing the effective exhaust area of the valves.

At the same time that ram conduit EI is closed;

the main exhaust valves F4, F4, F4' are opened.

Shortly after ram conduit EI is closed by rotary valve E5 and the. main exhaust valves F4,

F4, F4' are opened, the pistons uncover ports B9. A The exhaust valves and the ports B9 remain open during the latter part of the outstroke and the 1 iirst part of the instroke of piston I5 until fresh air from the rank case displaces the burnt gases j from the primary combustion chamber.

At the end of the outstroke of piston I5, when the air in crank case II is under maximum pressure, air enters the conduit D4 through check valve D8 which prevents that air from returning to the crank case when the pressuretherein is reduced. After the main exhaust valves F4, F4, F' are opened, the primary combustion chamber inlet valve D5 is opened long enough to admit the fresh compressed air in conduit D4 to primary combustion chamber DI whence it expels the burnt gases which pass from the cylinder through the exhaust valves. A light fuel is then admitted through injector D5 to primary combustion chamber DI where it is ignited by spark plugs D1, and the burning gases (from primary Vcombustion chamber enter cylinder I0 through opening D3 and ignite the fuel and air contained in cylinder lllshortly before the piston I5 ends its instroke.

It is to be understoud that, while the specificv embodiment of my invention which I have describedis a heavy-oil-burning internal combustion engine of the two-cycle type, the valve mechanism which I have invented is not limited in use to such an engine but may be applied to .der having three ports in its head, a Avalve for each of said ports', a pair of opposed cams mounted in the cylinder head casing for rotation about the axis of the cylinder, and radial rocker arms actuated by saidcams for operating said valves simultaneously.

-3. In an internal combustion engine, a cylinder having three ports in its head,v a valve' for each of said ports, a cam disc mounted in the cylinder head casing and having a pair of opposed cams, rocker arms actuated by said cams and adapted to open said valves simultaneously, and an adjustable connection between said rocker arms and said cams.

4. In an internal combustion engine, a cylinder -having a. plurality of ports in its head, a valve for each of said ports, a cam member mounted in the cylinder head casing, and mechanism actuated by said c am member for operating said valves,including a forked rocker arm mounted for pivotal movement in the cylinder head casing and extending outwardly from the axis of the cylinder along a fixed radial line, and means for permitting limitedv tipping movement of said rocker arm. 1

5. In an internalr combustion engine, a cylinder having a plurality of ports in its head, a valve for each of said ports, a casing enclosing the head of the cylinder and having oil channels on its inner surface, a disc mounted in said casing, a cam member mounted in said disc, mechanism supported by said disc and actuated by said cam member forV operating said valves, and means for forcing oil through the channels in said casing y haust ports and a set of low-pressure exhaust revolving the rotary valve at varying and said disc to said valve-operating mechanism. 6. In an'internal combustion engine, a cylinder having an inlet port and a plurality of exhaust ports in its head, an inlet valve, an exhaust valve foreach of said exhaust ports, a pair of opposed cams, means actuated by said pair of cams for opening all of said valves, and means for delaying the opening of the inlet valve until after the exhaust valves have been opened.

7. In an internal combustion engine, a cylinder l having a set of high-pressure exhaust ports and a set of low-pressure exhaust ports in its head, a

. valve for each of said exhaust ports, a cam member, and means actuated by said cam member for opening the high-pressure exhaust valves in advance of the low-pressure exhaust valves.

8. In an internal combustion engine, a cylinder having an inlet port, a set of high-pressure exports in its head, an inlet valve, an exhaust valve for each of said exhaust ports, a cam member,

`means actuated byv said cam member for opening each of said valves, means for opening the highpressure exhaust valves before the low-pressure exhaust valves, and means for delaying the opening of the inlet valve until after the low-pressure f xhaustvalves have been opened.

9. In an internal combustion engine, a cylinder provided with an exhaust valve, a conduit communicating with the crank case, an exhaust outlet, a valve chamber having one port communieating with the exhaust valve, another port communicating with the conduit and a third portl communicating with the exhaust outlet, and means for closing any one of said ports.

10. In an internal combustion engine, a cylinder provided with an exhaust valve, a conduit communicating with the crank case, an exhaust outlet, a valve chamber having one port communicating with the exhaust valve, another port communicating with the conduit, and a third port communicating with the exhaust outlet, a rotary valve adapted to close any one of said ports, and means driven from the drive shaft for speeds during each revolution of the drive shaft.

11. In an internal combustion engine, a cylin- I der having a-high-pressure exhaust valve, a conduit communicating with said high-pressure exhaust valve and with the crank case, a rotary valve between the conduit and the exhaust valve,

means for revolving the rotary valve, means for opening the' high-pressure exhaust valve when (the yrotary valve is opened, and means for accelerating the rotation of the rotary valve to close; it shortly after -the high-pressure exhaust valve is opened.

12. In a two-cycle internal combustion engine, a cylinder head containing a plurality of valve ports .whose combined area is equal to a large proportion of the area of the cylinder head,`

valves controlling said ports, means for opening some of said valves in advance of the others, and means for Idirecting the exhaust from the a conduit connecting theprimary combustion l chamber with the crank case, means forforcing r 15. In a multi-cylinder engine having cylin- A ilrst opened valves into a super-charging'device j so that air in the crank case may expel the fumes from said conduit through -the exhaust outlet.

^ 14. In an, internal combustion engine, a cylinder constituting the main combustion chamber of the engine and having an exhaust valve and a nre inlet opening, a primary combustion chamber communicating with said tire inlet opening, 30

compressed air into said conduit, means for opening the exhaust valve, and means for admitting compressed air from the conduit to the primary combustion chamber after said exhaust valve is opened.`

ders containing valves in their heads, a casing `secured to the head'vof each cylinder, aligned shafts each of which extends transversely through one of the casings with its ends projecting short distances outside the casing, avalvecontrolling mechanism in each casing. actuated by the transverse shaft of that casing, and detachablecoupllngs connecting the ends of the aligned transverse shafts of the casings of the different cylinders.

16. In an internal combustion engine, a lcylinder provided with lan exhaust valve, a conduit communicating with ther crank case, an exhaust outlet, a valve chamber having one port-communicating with the exhaust valve, another port communicating-withthe conduit, a third port communicating with the exhaust outlet, and a rotary valve adaptedv to close saidports singly .s and in sequence so that the intervals during which the respective ports are closed arev of unequal du'ration.

- WILLIAM HARPER, Jn.

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