US2138131A - Cylinder head and combustion chamber for internal combustion engines - Google Patents

Description

l. E. ASKE 2.l38,13l

' Filed Jan. 9, 1956 s sheets sheet 1 r 4 f R w." \w 4 a m w m 3 u v z a z w. fl .i/\ H 2 1 m fl U 2 7 w M 5 v i I a V .1 w m v 2 1 Nov. 29, 1938.

CYLINDER HEAD AND COMBUSTION CHAMBER FOR INTERNAL COMBUSTION ENGINES BY aka/1114 W 1PM- ATTORNEY Nov. 29, 1938. E ASKE 2,138,131

CYLINDER HEAD AND COMBUSTION CHAMBER FOR INTERNAL COMBUSTION ENGINES Filed Jan. 9,- 1936 3 Sheets-Sheet 2 z ay W 2v zl 7 I Z 4 7w q I 49 Z W J INVENTOR [PW/Y6 ids/(4' B Y ATTORNEY Nov. 29, 1938. I LE, ASKE 2,138,131

CYLINDER HEAD AND COMBUSTION CHAMBER FOR INTERNAL COMBUSTlON ENGINES Fi led Jan. 9, 1936 s Sheets-Sheet 3 :f/marl/ n arana w fZ/WE Zeal/E4 m Pzecr/vr or 7077 4 INVENTOR few/v 5. K:

BY M w. Dal/ 1,

ATTORNEY Patented Nov. 29, 1938 CYLINDER HEAD AND COLIBUSTION CHAM- BER FOR INTERNAL COMBUSTION EN- GINES Irving E. Aske,-Muskegon, Mich., assignor to Campbell, Wyant & Cannon Foundry -Company, Muskegon Heights, Mich, a corporation of Michigan Application January 9, 1936, Serial No. 58,273

8 Claims.

My present invention relates to internal combustion engines and particularly to combustion chambers thereof, and g The objects of my present invention are, to improve distribution of the combustible mixture within the combustion chamber of-the engine; to increase.the throat opening between the combustion chamber and the cylinder without introducing roughness in the engine; to minimize roughness of combustion caused pressures; to cause a substantially uniform progressive rise of combustionpressureto the engine's piston; to lessen noise and vibration of the engine and to increase the horse power output of the engine per unit of fuel burned. I

In carrying out my invention and to obtain the aforesaid objects, it is necessary to set forth certain geometrical relations applying to the shape, length, volume and spark plug location of the combustion chamber, whereby the designer can accurately lay out a combustion chamber to more closely approach the ideal form without having to resort to cut and try methods involving many actual tests on an engine.

Therefore, to understand my invention, it is necessary to know certain fundamental facts concerning the combustion process that have been established by scientific investigation, to wit: that the ignition spark ignites only that portion of the fuel mixture which closely surrounds it, that the initial combustion ignites the succeeding layers of adjacent fuel giving rise to an inflammation wave that spreads progressively throughout the gaseous fuel mixture until all combustibles therein are consumed, that the velocity of combustion or chemical reaction is approximately equally rapid in all directions, which thereby, unless obstructed, forms a spherically shaped wave front, that the volume contained in the inflammation wave front equals that of the incremental portions of mixture it encounters at any instant, and that the volume of the incremental portions consumed are determined by the volume and shape of the combustion chamber as related'to the position of the 'point of ignition, that pressures developed at any instant, of combustion are proportional to the ratio of the incremental fuel volume'consumed in the wave front to that of the entire volume to be burned. Hence, pres-determination of rates and values of pressures generated are possible through proper control of volume distribution in the combustion chamber, as related to the ignition spark at the spark plug.

It is further understood that when small cal details.

volumes of fuel begin to burn, pressures are generated which rapidly increase as the burning process continues and the rapidity of these changes in pressure set up reaction forces against the piston head, connecting rod; crankshaft, and bearings which act as a sudden and blow-like impulse. The greater the volume of fuel burned at any instant in the inflammation wave front, the greater becomes the acceleration of pressure created and the greater the magnitude of the reaction and restoring forces.

The magnitude of the said reaction force is a measure of the roughness of the engines operation and its effects in producing vibration are far more pronounced than the maximum pressure v second. If the growth of this unit pressure was limited to one-half the former volume of fuel, the acceleration would be reduced to twenty-five thousand pounds per second. When multiphed by the area of the piston this reaction force be- Y ,comes very large, creating noisy operation and also damage to engine bearings. It is obvious in the light of these factors that the arrangement of combustion volume distribution considered from the point of ignition must be carefully done in designing'a combustion chamber if engine roughness is to be minimized, as distinguished from combustible volumes that are haphazardly arranged as practiced in conventional combustion chamber designs.

In present designs of combustion chambers, the skill of the designer isrefiected by his ability to provide maximum power output of the engine, and economy thereof through choice of mechani- Very little attention has been paid. to the importance of volume distribution and its effects upon the performance of the engine. And, where these factors have been considered, no definite pattern or bogey has been established by geometrical considerations to guide designers in their lay-out of the combustion chambers for various engine sizes and compression ratios.

I attain the above named objects and others not at this time enumerated by distributing the volume of the combustion chamber in accordance with the following description when taken in connection with the accompanying drawings illustrating the preferred embodiment of my invcntion, in which:

Fig. 1 is a cross-sectional view of the cylinder head taken on irregular line II of Fig. 5.

Fig. 2 is a sectional view taken on line 2-2 of Fig. 5.

Fig. 3 is a fragmentary sectional view illustrating the cup-like cooling fluid depression over the engines exhaust valve.

Fig. 4 is a sectional view taken on line 4-4 of Fig. 5.

Fig. 5 is an under or closing-side plan view of the cover showing the preferred arrangement of the combustion chamber and parts pertaining thereto.

Fig. 6 is a plan view illustrating an alternative arrangement of the combustion chamber and parts, and

Fig. '7 is a chart illustrating the rate of change of concentrically spherical volumes considered from the source of ignition to the farthest boundary point of the combustion chamber as shown in Fig. 5.

Throughout the several views of the drawings,

similar numerals refer to similar parts, and referring thereto:

der closing face 3, in which is formed combustion chamber 4, having a long extended portion 5 and a shorter extended portion 6 joined to the long extended portion 5 by curved wall I. The combustion chamber boundary wall 8 extends in an irregular curve from the long extended portion 5 to around the spark plug position 9 joining, by reverse curve extending around the exhaust valve chamber portion I0 to the short extended portion 6. The upper wall or ceiling I I has a curved depression I2 extending from the wall 8 at one side of the combustion chamber to the wall at a point between the exhaust valve position and the spark plug position. Boss I3 extends into the combustion chamber to bring the cooling fluid near the exhaust valve I4 thereby preventing excessive heating of the exhaust valve. The boss I3 also may serve to support heat transfer member I5 which is used in cases of extremely high compression and high combustion temperatures.

The heat transfer member I5 is held in place by casting the cover body wall l6 onto it. Spark plug I'I provides the electric arc spark for igniting the fuel charge in the. combustion chamber and is preferably located over the fuel inlet valve I8, as shown in Fig. 1.

Fig. 6 illustrates the spark plug I! located over the exhaust valve position"; with the long extended portion 5 of the combustion chamber on the same side of the chamber as the spark plug; While this location is operable and minimizes engine roughness, it does not to the same extent as when the spark plug is located over the fuel inlet valve and with the long extended portion 5.

on the same side of the combustion chamber "as the spark plug. I9 illustrates the cylinder block of the engine closed by the cover body I except for the opening 20 between the combustion chamber 4 and the engine cylinder bore 2|. 22 represents the gasket between the cover body I and the cylinder block I9. Suitable bolts passing through holes 24 secure the cover in place on the cylinder block.

Heat transfer member 23 pertains to the subject matter of my earlier application, Serial No. 736,477, filed July 23, 1934, and forms no part of my present invention.

Interrupted circular line 25 designates the peripheral line of the engine cylinder.

Referring to Fig. 7, the graph indicates the space rate of change of incremental volumes consumed at constant pressure as the inflammation wave spreads through to the outermost limits of the chamber shown in Fig. 5. This is illustrated by the curve 0EPC. The ordinate .HP taken at the point of maximum value representing 25% of the total radial distance of the chamber, corresponds to the ratio of 136%. This value indicates that the volume consumed is increasing 1.36 times as fast as the lineal radial distance for the same interval F, which represents 5% of the total radial distance. The distance from the spark plug to the outermost limit or boundary of the chamber is designated by line X in Fig. 5

and fixed at of the radial distance in the chart of Fig. '7. The interval F corresponds to the interval Y of Fig. 5 where Y represents a lineal radial distance or increment swept through by the flame as it travels beyond the radius 0M. During this interval, volume v is consumed which represents a percentage ratio of I00 where V represents the total volume of the chamber and considered as 100% of the volume burned in establishing the graph. As the flame. advances a distance Y in Fig. 5 from 0M and conby the ratio 1 V X v 1oo='{, 100, m which X I00 is the percentage increase of volume burned and I00 is the percentage increase in distance th flame advances in distance Y.

The line 0ABC is the proposed bogey within which the volumetric rates of change will substantially occur for all combustion chambers coming within the scope of my invention. The bogey is defined by three lines connecting the points 0, A, B and C of the chart shown in Fig. 7. Point 0 is the initial or starting point of the graph from which the rates of change of. volume and flame travel distance in percent are reckoned. The abscissas and ordinates of points A, B, C are designated respectively by the figures (I6,

I50), (85, I20) and (I00, 40) the ratio I00 establishes the value of abscissas and xx vY.

I00 the ordinates. The shape and amplitude of the curve 0EPC depends upon the position of the spark plug relative to the volumes of fuel to be burned and the shape of the chamber. .As there are an infinite number of positions for a spark plug in any combustion chamber of given shape.

and volume there -will be found only one location which will substantially satisfy the condition imposed by the boundary chart or bogey and give uniform increase in combustion pressures.

The bogey UABC of Figure 7 was established by analyzing the combustion volume distribution, considered from the ignition point, of many combustion chambers used in present day engines, and noting from measurements of vibration and noise the relative harshness of the engine in operation; fromfthese observations, it was found that when the maximum space rate of change of volume took place within forty percent of the total distance from the ignition spark to the outermost end of the combustion chamber, there was improvement over a chamber designed havingthe same maximum value occurring at a greater distance from the ignition spark. Hence, the peak of the bogey BABC Figure 7 was established as well as the lower limit. Any chamber graphically analyzed and .coming substantially within the bogey OABC will be satisfactory.

In analyzing a combustion chamber for volume distribution, I employ a plaster of Paris cast made of the entire interior of the combustion are in the form'of powder, represent the progress of the wave front of flame as it travels through the chamber, and the weight of these powdered incremental sections represent relatively exact proportions of the fuel mixture that are burned, which is expressed in percent of the total weightof the cast. Thus, it is possible to cut up the cast of plaster of Paris chamber into a large number of increments and chart out the space rate of change of volume for 'each and every radial section. The increment of radial distance corresponding to the volume removed is expressed in percent of the total distance measured to the outer boundary of the chamber cast. The percent volume represented by each increment dividedby the corresponding percent radial increment in distance multiplied by one hundred establishes the points on the graph OEPC of Figure 7. The graph therefore represents the space rate of change of volume for the flame front as it advances through the mixture from the spark plug to the outermost boundary of the combustion chamber.

In my present invention, combustion takes place at reaction velocity and in a preferred and predetermined manner, as illustrated in Fig. 5. It starts atthe ignition spark between the terminals of the spark plug, preferably located in the portion of the combustion chamber above the fuel inlet valve and spreads in a supposedly concentrically spherical wave front consuming combustibles in proportion to the volumes swept through from the ignition spark to the curved wall 1 and into the extended portions 5 and 6 of the combustion chamber, then through the passage 20 into the clearance space between the piston and-the face 3 of the cover. The area of the throat passage 20 is considerably greater than the area of the inlet valve opening and is substantially closed by the engine piston at the start of combustion. The combustion wave starting at the ignition spark and. spreading in a supposedly concentrically spherical form encounters first the curved wall I, spreads thereover and progressively advances into the extended portion I tance.

5, the outermost boundary point of the chamber,

having consumed all combustibles in its path in proportion to the incremental volumes encountered. Thus, the progression of the combustion front from the point of ignition.

The space between the engines piston and the face of the cover and designed as the piston clearance is thin and being of considerable area in proportion to the volume enclosed, the flame is rapidly cooled and controlled in its reaction velocity. The heat transfer member i5, in contact with combustibles within the combustion chamber directly over and asnear as practical to the exhaust valve, tends to cool that portion of gas in contact with the exhaust valve and thereby limit the heating of the exhaust valve to a temperature that will not cause premature ignition of the fuel charge. Also,'the raised boss l3 projecting into close proximity to the exhaust valve brings the cooling fluid close to the latter when understood that the invention is not to be limited to the particular illustrative embodiment disclosed, the scope of inventionbeing set forth i the following claims.

I claim:

1. In an internal combustion engine, a cylinder head with a combustion chamber therein provided with ignition means, the said chamber having concentrically spherical volume portions so related to the point of ignition, that the total volume of the combustion chamber and total radius distance from initial ignition that the respective ratios expressed in percent of any increment of said volume to the total volume divided by the corresponding ratio of incremental radius to the total radius distance shall come substantially within the limits of 150% during the first 40% of the radius distance from the point of ignition and reducing to within 120% at 85% of the said distance and then rapidly dropping to within 40% at 100% of the said dis- 2. In an internal combustion engine, a cylinder head with a combustion chamber therein, provided with ignition means, said chamber having concentrically spherical portions so related to the point of ignition, total volume ofcombustion chamber and total radius distance from initial ignition that the percentage rate of change of volume for any incremental radius of flame travel advance from the point of ignition shall come substantially within the graphical limits prescribed by the said bogey 0, A, B, G'of Fig. 7.

3. In an internal combustion engine, a cylinq der block, a cylinder, a piston contained therein, a cylinder cover attached to said block, a gasket between said cover and said block, forming a clearance volume between said cover and piston, a combustion chamber common to said cover and top of said piston, an ignition point contained within said chamber, said combustion chamber -having concentrically spherical volumes so related to the ignition point, total combustion volume and maximum radius distance that the maximum ratio of any radial increment of combustion volume to the total volume multiplied by one hundred, and divided by the corresponding ratio of incremental radius to the total radius distance, shall not substantially exceed 160% between the limits of 40% and 85% of the radius distance from the said ignition point, the maximum radius representing the distance from the said ignition point to the outermost edge of said chamber and the total volume represented by the total combustion space enclosed by said chamber, and said clearance volume when the said piston is at the top'of said cylinder.

4. In an internal combustion engine, a cylinder block, a cylinder, a piston contained therein, a cylinder cover attached to said block, a gasket between said cover and said block forming a clearance volume between said cover and piston, an ignition point contained within said combustion chamber, said combustion chamber having concentrically spherical volumes so related to the ignition point, total combustion volume and maximum radius distance that the maximum ratio of any radial increment of combustion volume to the total volume multiplied by one hundred, and divided by the corresponding ratio of incremental radius to the maximum radius distance, shall come approximately within the limits of 160%, between the respective limits of 16% and of the radius distance from the said ignition point, the maximum radius distance representing the distance from the ignition point to the outermost edge of said chamber and the total volume represented by the total combustion volume enclosed by said chamber and said clearance volume when under maximum compression by said piston.

5. In an internal combustion engine, a cylinder block, a cylinder, a piston contained therein, a cylinder cover attached to said block, a gasket between said cover and said block forming a clearance volume between said cover and piston, an ignition point contained within said combustion chamber, said combustion chamber having concentrically spherical volumes so related to the ignition point, total combustion volume and maximum radius distance that the maximum ratio of any radial increment of combustion volume to the total volume multiplied by one hundred, and divided by the corresponding ratio of incremental radius to the total radius distance, shall come substantially between 150% and 100%, between the respective limits of 70% and 85% of the radius distance from the said ignition point, the maximum radius distance representing the distance from the ignition point to the outermost edge of said chamber and the total volume represented by the sum total of combustion volume enclosed by said chamber and said clearance volume when thecombustion volume is under maximum compression by the said piston.

6. In an internal combustion engine, a cylinder block, a cylinder, a piston contained therein, a

cylinder cover. attached to said block, a gasket between said cover and said block forming a clearance volume between said cover and piston, a combustion chamber common to said cover and piston, an ignition point contained within said chamber, said combustion chamber having concentrically spherical volumes so related to the ignition point, total combustion volume and maximum radius distance that the percentage rate of change of volume for any incremental radius of flame travel advance from the ignition point shall come substantially within the limits of 150%, 120% and 40% at the respective radius distance of 16%, 85% and 100% from the said ignition point, the maximum radius distance representing the distance from the said ignition point to the outermost edge of the said chamber and the total volume represented by the total combustion space enclosed by said chamber and said clearance volume when said piston is uppermost in said cylinder.

7. In an internal combustion engine having a cylinder block, a cylinder, a piston contained therein, a cylinder cover attached to said block, a gasket between said cover and said block, a clearance space between said cover and piston, a combustiton chamber in said cover common to said cylinder and piston, an ignition point contained within said chamber, said ignition point so located with regard to the extremities of the said combustion chamber and said cylinder that the radial distance measured from the said ignition point to the outermost edge of the said chamber shall not exceed 68%, nor be less than 58% of the radial distance between the said ignition point and the outermost edge of the said cylinder.

8. In an internal combustion engine, a cylinder block, a cylinder, a piston contained therein, a cylinder cover attached to said block, a gasket between said cover and said block forming a clearance volume between said cover and piston, an ignition point contained within said combustion chamber, said combustion chamber having concentrically spherical volumes so related to the ignition point, total combustion volume and maximum radius distance that the maximum ratio of any radial increment of combustion volume to the total volume, multiplied by one hundred, divided by the corresponding ratio of incremental radius to the total radius distance, shall come substantially between 150% and 100%, between the respective limits of 70% and 85% of the radius distance from the said ignition point, the maximum radius distance representing the distance from the ignition point to the outermost edge of said chamber and the total volume represented by the sum total of combustion volume enclosed by said chamber and said clearance volume when the combustion volume is under maximum compression by the said piston.

navnvor E. AsKE

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