US2826185A

US2826185A - Combustion chamber for engines

Info

Publication number: US2826185A
Application number: US452092A
Authority: US
Inventors: Paul F Keydel; George C Trevarthen
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1954-08-25
Filing date: 1954-08-25
Publication date: 1958-03-11
Anticipated expiration: 1975-03-11

Description

March 11, 1958 P. F. KEYDEL ETAL 2,826,185

I COMBUSTION CHAMBER FOR ENGINES v Filed Aug. 25, 1954 INVENTORS ATTORNE! ited States Patent "'0 COMBUSTION CHAMBER FOR ENGINES Paul F. Keydel and George C. Trevarthen, Detroit, Mich., assignors to General Motors Corporation, Detroit,

Mich, a corporation of Delaware Application August 25, 1954, Serial No. 452,092

4 Claims. (Cl. 123-191) I This invention relates to combustion chambers for engines and has particular relation to combustion chambers especially applicable foremployment in four stroke cycle, spark ignited, internal combustion engines for automotive and other uses.

It is proposed to provide a combustion chamber that willoperate smoothly and 'efliciently at compression ratios exceeding 8 to 1, that may .be employed with a piston of symmetrical and balanced design, thatwill embody only-plane surfaces and surfaces of rotation and that may be easily and accuratelymachined and otherwise manufactured-sothat the volumeof all combustion chambers employed in any engine will be the same within close limits.

It is also proposedto provide a combustion chamber in which a firing chamber willbeformed at one side of the cylinder and at one side of the inlet and exhaust valves in the head of the cylinder and in such position that the spark plug may be. located substantially in the middle of thecharge compressed within the firing chamber. The firing ichamber communicates at one side thereof with a minimum mechanical clearance space extending throughout approximately half of the cross sectional area of. the cylinder. The volume of. the charge compressed in the clearance. space will be a considerable portion of the total volume ofthe charge and will confine the last part of the charge to burn in a space where the surface area to volume ratio is relatively high.

In the drawing:

1 Figure 1 is a fragmentary cross sectional .view of a multicylinderor other engine having combustion chambers embracing the principles of the invention.

Figure 2 is a fragmentary crosssectional view of the engine takensubstantially in? the plane of line 2-2- on Figure 1 and illustrating particularly the head end of the piston employed in one cylinder of the engine.

Figure 3 is a fragmentary cross sectional view of the engine disclosed by Figure 1 and is taken-substantially in the plane of: line; 3-3 on Figure 1 looking in the direction of the arrowsthereon.

The engine 10 may be a multicylinder engine of-any design and may include a liquid cooled cylinder block 11 and head 12. The block 11 may include one ormore cylinders 13 in which pistons 14 are adapted to reciprocate during the operation of the. engine. The block 11 may be formed in such a way as to provide an ,upper wall 416, the outerusurface. of. which is arplanesurface perpendicular to the axes of'the cylinders 13 and at which the plane end surfaces .17 of the pistons 14 may terminate at the outer dead center positions of the pistons 14 within the cylinders 13. The head 12 also may have a lower wall 18 having a plane outer surface which is also normal to the axes of the cylinders 13. The head 12 may be secured to the block 11 on a gasket 19 engaging the plane surfaces of the wallsjlqa and 1d.

The combustion chamber 21' for each cylinder of the engine may be formed by providing a cavity 22 in the head .12 and in such manner as to form a firing chamber 23 at one side of the cylinder and a minimum mechanical clearance space '25 at the opposite side of the cylinder, :Whenthe piston ,14 is at; outer. dead center posi- ".2 tion within the cylinder. The cavity 22 may be formed in .any desired manner but it ispreferred to form the cavity in. such. manner that it maybe easily machined .or otherwise finished to exact dimensions so that each combustion chamber 21 withinthe engine 10. may, have substantially the same volume. ;.It is, therefore, proposed to form the cavity' 22,in,such manner as to provide a planev end, surface 24..and.oppositely disposed fragmentary toroidal side surfaces 26 and 27. Thesurerably a fragment of a;frusto conical or rectilinear surfaceof revolution with the larger end thereof. merging .with..the.sur face 26 and the smaller end. thereof merg- .ing with the outer. end. of the cylinder 13'throughout approximately half of the cylinder 13 and atone side of, thecylinder 13. .Thecavity 22 may be formed by a tool haying a cross sectionalconfiguration in a plane through the axis of rotation thereof. substantiallyacorresponding to the

surfaces

24, 26 and 27. The tool may be rotated. about an .axis perpendicularto-the surface 24 and the axis may move laterally or rotationally during the rotation of the tool.

. It will be apparent that. the toolwill very accurately machine. the cavity 22 sothat allof the cavities for the cylinders of thevengine-may enclose substantially equal volumesof compressed charge.

, It is. proposed to locate'the inlet and exhaust yalves 28 and 29 respectively for each cylinder of the engine -in the head of the engineand' in such manner that the valves will extend substantially across a idiametenof each cylinder with the inner surfaces of the .yalvessubstantially in the plane .of the surfaces 24. .Undensuch circumstances it will be possible to employ the largest possible sizes of valves with the inlet valve .28- bei ng somewhat larger than'the exhaust valve .29. for each cylinder of the engine.

The inlet and exhaust valves 28and 29 are adapted to open and close inlet and exhaust passages-48 and 49 whichare formed in the head 12 for eachcylinder of the engine.

surface of the lower wall 18 will extend inwardly over a considerable part of the end of the cylinder 13. Under such circumstances. the adjacent surface of the head .12 in directly opposed relation to the end of the cylinder 13 of the engine will comprise a noimally disposed plane surface outside the chord and the sloping and arcuate surfaces 24, 26 and 2'7.

It is preferred .to employ a piston with the combustion chamber 21 having a projection 31 extending from the plane end surface 17 thereof and having plane side Walls 32 and 33 which intersect substantially along a diameter of the cylinder 13 and which slope at equal angles with respect to the end surface 17. The slope of the surfaces 32 and33'may be the same as the slope of the surface 24 with the surface 32 being spaced from the surface 34 so as to provide a part of the minimum mechanical clearance space indicated at 25. It is also preferred that the axes of the stems of the valves 28 and 29 be located in a plane substantially parallel to the line of intersection of the surfaces 32 and 33. Further, it is preferred to make the surface 26 of such extent that the inner edge of the surface will intersect the end of the cylinder 13 substantially atthe diameter of thecylinder 13 so that the surface '26 will curve inwardly at the 'opposite'ends ofthe asaarss valves 28 and 29 and will merge with the inner surfaces of the valves 28 and 29 substantially in the plane of the ends of the valves and the surface 24. In order to provide for the maximum size for the valves 28 and 29 it is proposed to recess the surfaces 24 and 26 as is indicated at 34 so that the seats for the valves may be formed outwardly slightly beyond the surface 24 and so that clearance may be provided at the ends of the valves and within the surface 26. It is proposed to form the surfaces at the ends of the projection 31 as curved surfaces 36 which are spaced from the surface 26 by an amount substantially equal to the thickness of the mechanical clearance space 25. It is proposed to locate the spark plug 37 for each cylinder of the engine in such manner that it will project into the firing chamber 23 substantially in the middle of the firing chamber. This may be done by disposing the spark plug at such an angle that the spark gap between the ignition terminals 38 of the spark plug will be substantially on a diameter of the cylinder normally intersecting the plane of the stems of the valves and on the curved line between the surfaces 24 and 26. The head may be relieved as is indicated at 39 by a cone shaped surface concentric with the axis of the plug and extending towards the valves, to prevent the formation of a pocket within the spark plug and adjacent the terminals thereof.

With such construction it will be apparent that the larger part of the charge which is compressed within the firing chamber 23 will be located in a relatively compact chamber with the spark gap between the ignition terminals of the spark plug in position so that the charge will burn rapidly in all directions from the end of the plug thereby burning the greater part of the charge in a relatively short time. The part of the charge in the clearance space will commence to burn when the burning of the charge in the firing chamber 23 is substantially completed and will continue to burn thereafter until the burning ends at the opposite side of the cylinder, Notwithstanding the increase in density and temperature of the last part of the charge to burn within the clearance space 25 it will be possible to burn relatively low octane fuel at high compression pressures and without detonation, due to the relatively large surface area to volume ratio in the mechanical clearance space 25. It will be noted that the mechanical clearance space 25 extends substantially throughout one-half of the area of the end of the piston 14 and the cylinder 13 thereby insuring that the part of the charge compressed in the firing chamber 23 will be uniformly mixed and that the quality of the mixture will be suitable for burning at the highest possible rate. it will be noted that the part of the mechanical clearance space 25 which is formed between the surface 32 and the surface 24 is in a plane including the spark gap between the terminals 3%. This will insure that the final blast of the charge being compressed will be directed toward the spark gap between the terminals 38, thereby insuring that the terminals will be surrounded by a properly mixed part of the charge, the burning of which will commence as quickly as possible after ignition occurs.

We claim:

1. A combustion chamber for engines having a cylinder and a head and having a piston adapted to reciprocate within said cylinder, said combustion chamber being formed by a cavity in the head having a plane end surface intersecting the end of the cylinder on a chord extending across said cylinder, said cavity forming a firing chamber at one side of the cylinder, said piston being formed at the end thereof to provide a plane end surface disposed in uniformly spaced relation to said head beyond said chord and having a projection extending from said piston end surface, said projection being formed by obliquely disposed plane surfaces intersecting within said cavity substantially on a diameter of said cylinder and with one of said surfaces being disposed in substantially parallel relation to said plane end surface of said cavity.

2. An engine comprising a cylinder having a piston adapted to reciprocate therein and a head adapted to close the end of said cylinder beyond said piston and having a combustion chamber formed therein between said head and said piston and said cylinder, said combustion chamber being formed to include a cavity extending into said head and having an end wall disposed obliquely with respect to the axis of said cylinder, said piston being formed to provide a projection at the end thereof extending into said cavity and having a plane wall surface on one side of said projection extending in substantially parallel relation to said end wall of said cavity, said plane wall side surface of said projection being formed to extend toward one side of said cylinder from a line forming a diameter of said cylinder, said projection on said piston being formed to extend from a plane end surface forming the outer end of said piston and disposed normally to the axis of said cylinder.

3. An engine having a cylinder with a piston adapted to reciprocate therein and having a head for closing the end of said cylinder and comprising, a combustion chamber formed between said head and said piston and including a firing chamber formed in said head and having an obliquely disposed end wall and oppositely disposed toroidal side walls, said piston being adapted to extend within said cavity and being symmetrical on opposite sides of a diameter of said cylinder and having a side wall disposed in substantially parallel relation to said end wall of said cavity, a pair of inlet and exhaust valves disposed in said head and opening into said end wall and extending across said cylinder substantially on a diameter of said cylinder, and a spark plug projecting into said cavity with the ignition terminals thereof projecting through said obliquely disposed end wall in directly opposed relation to the space between said piston side wall and said end wall of said cavity.

4. A combustion chamber for engines comprising a piston adapted to reciprocate therein, a head for said piston having a lower wall adapted to be secured to the end of said cylinder, said lower wall being formed to provide a plane surface adjacent the end of said cylinder disposed in normal relation to the axis of said cylinder, a cavity formed in said head and including a plane end surface intersecting said plane lower surface of said head and including oppositely disposed toroidal side surfaces, said side surfaces being surfaces of revolution formed about an axis perpendicular to said end surface, said piston being formed to provide an end wall having a projection extending into said cavity, said projection being formed by oppositely disposed side surfaces intersecting substantially on a diameter of said cylinder and being obliquely disposed with respect to said cylinder, one of said piston side surfaces being parallel to said plane end surface and forming a minimum mechanical clearance space with said plane end surface when said piston is at outer dead center position in said cylinder, a pair of inlet and exhaust valves opening through said plane end surface of said cavity and into the central part of said cylinder, and a spark plug projecting through said head with the terminals thereof disposed between said valves and in opposed relation to said mechanical clearance space, one of said oppositely v disposed toroidal surfaces of said cavity being adapted to substantially merge with the outer end of said cylinder throughout substantially one half of the peripheral edge of said cylinder.

References Cited in the file of this patent UNITED STATES PATENTS ,098 Fedden Mar. 30, 1926 35 Swaine May 12, 1942 FOREIGN PATENTS 51 Australia May 19, 1931