US2151428A - Combustion chamber - Google Patents

Description

March 21, 1939. N JANEWAY 2,151,428

COMBUSTION CHAMBER Filed July 31, 1935 Patented Mar. 21, T939 UNITED STATES COMBUSTION CHAMBER Robert N. Janeway, Detroit, Mich.) assignor to Chrysler Corporation, Detroit, Mich, a corporation of Delaware Application July 31, 933, Serial No. 682,989

-14 Claims. (01. 123-113) J This invention relates to improved combustion chambers for internal combustion engine cylin- 'der heads and particularly to an improved wall structure for such chambers.

5 More specifically, the invention relates to the provision of metals having different thermal conductivities at selected portions of the walls of a combustion chamber.-

During the combustion of each charge of fuel l mixture in a chamber of this character the flame front of the combustion progressively travels from the end of the chamber at which combustion initiates toward the opposite end of the chamber and the unburned portions of the .charge in advance of the flame front are subjected to compression of increasing magnitude. Such unburned portions are accordingly subjected to temperatures of increasing values. In order to prevent severe detonation, the permissible compression ratio of a combustion chamber is limited by the maximum pressure and temperature to which the final portions of the unburned fuel are subjected at the end of each combustion.

I have found that by providing walls compris- 2 ing metal having a relatively high thermal conductivity throughout those portions of the chamber which, prior to ignition and after compression, contain the fuel mixture constituting the last portions of the charge to be burned, material- 0 ly higher compression of the final portions of the charge is permitted without exceeding the maximum permissible temperature and therefore a combustion chamber having a higher compression ratio can be used without causing objectionable detonation and the difiiculties encountered in the use of cylinder heads composed entirely of high thermal conductive metals are eliminated for it is not necessary to bolt together parts formed of metals having dilferent expansion coefficients such as, for example, a cast iron cylinder block and an aluminum alloy head. Rapid conductivity of heat to the'cooling medium from those parts of the combustion chamber which initially contain the fuel mixture of the last portion of the charge to be burned is provided for without excessively cooling the remaining portions of the chamber below the temperatures required for the proper initial combustion stages.

The main objects of the invention are to pro- 60 vide improved combustion chamber wall structure in an internal combustion engine cylinder head which permits the compression ratio of the head to be increased materially above that conventionally used without causing objectionable detonation; to provide combustion chamber wall structure having a higher thermal conductivity at the part thereof which, prior to ignition and after compression, embraces the fuel ultimately .contained' in the portion of the fuel charge that is last to be burned, than. throughout the portion of 5 the chamber in which the early stages of combustion take place; to provide a composite wall between the cooling medium passage and combustion space of a cylinder head having a section comprising metal of relatively high thermal conductivity located at that portion of the chamber which registers with the cylinder bore of the engine and having a section comprising a. metal of a lower thermal conductivity in the region of the intake and exhaust valves of the engine; to provide a combustion chamber wall structure of this characterhaving copper or copper alloy wall sections of relatively high thermal conductivity and in which the metal of the cylinder head, preferably cast iron, constitutes the portions of the wall structure of lower thermal conductivity; to provide a copper or copper alloy plug in the partitioning wall between the combustion space and cooling medium passage of a cylinder head, which registers with and extends over substantially the entire area of the cylinder bore; to provide a plug of this character having an offset portion constituting the end wall and parts of the side walls of the combustion chamber and which also includes a fragmentary substantially flat rim for providing the upper boundary of that portion of the clearance space which is located between the outermost position of the piston and the closest adjacent surface of the head of the engine where the final stages of combustion take place; and 35.

to provide a plug of this character which has its. peripheral edge portions integrally welded to the edges of an opening in the cylinder head structure in which the said plug is received.

Illustrative embodiments of the invention are 40 shown in the accompanying drawing, in which:

Fig. 1 is a fragmentary transverse vertical sectional view of an internal combustion engine having a cylinder head provided with a combustion chamber embodying my invention.

Fig. 2 is a fragmentary plan view of the inner side of the cylinder head taken on the line II-I[ of Fig. 1 showing, in dot and dash lines, the relation of the cylinder bore and intake and exhaust valves with respect to the combustion chamber.

Fig. 3 is a fragmentary sectional view of a combustion chamber wall embodying a further modification of my invention.

In the form shown my improved combustion chamber is illustrated in a cylinder head of an therein and laterally spaced longitudinal adjacent exhaust and intake valves l3 and I4 respectively. The engine is provided with a cylinder head II in which there is formed a cooling medium circulating passage IS. The cylinder head ll preferably comprises cast iron and it is detachably secured to the cylinder block I by bolts l1, a gasket l8 being interposed between the adjacent faces of the block and head II and I5 respectively.

The cylinder head I! includes a top wall l3 and a lower composite wall. 20 comprising metals of different thermal conductivities and which serves as a partition between the cooling medium e I and a chamber 2| provided above the cylinder bore and valves l3 and M for the reception andcombustion of the fuel mixture. The lower wall 20 is formed to the contour required to produce a desired combustion chamber shape, such as that illustrated in Fig. 2, wherein the combustion chamber extends from the valve side of the cylinder block over a substantial portion of the cylinder bore. The composite wall 20 comprises a section 22 which is formed of the same metal as the main portion of the cylinder head and which is located at the valve end of the chamber and another section 23, comprising metal of a substantially higher conductivity than that of the wall section 22. The section 23 comprises a plug having a circular outline and formed, preferably of copper or suitable alloys containing copper or aluminum. This plug is receivable in an opening 24 of corresponding outline formed in the lower wall 23 of the cylinder head and it is integrally united with the remaining wall structure of the cylinder head by a suitable welding operation.

In the form shown, the opening 24 has tapering side walls 26 which conform with correspondingly tapered side edges on the plug 23. In manufacturing a cylinder head of this character a ribbon 21, comprising welding metal, is provided between the tapering edges of the opening and plug respectively and the latter is temporarily frictionally held in place by firmly pressing it into the opening. The cylinder head is then preferably heated in an atmosphere of hydrogen to a sufliciently high temperature to fuse the metal of the welding ribbon 21 with the metal of the plug 23 and with the metal of the surrounding structure of the cylinder head. This welding operation has been found to be commercially satisfactory although it is recognized that the plug. 23-may be welded in place by various other well known processes.

In the illustration shown, the plug 23 extends over substantially the entire area of the cylinder bore and it constitutes those portions of the wall structure of the combustion chamber 2| which, after the fuel charge is under compression and prior to ignition, embrace the fuel mixture contained in the last portions of a fuel charge to be bumed'. In the L head engine shown, the combustion of the last portions of the charge to be burned takes place in the clearance space 23' between the portions of the surfaces of the top plug 23 there is a fragmentary rim 23 which extends beyond the cylinder end wall 21 of the chamber and over the remaining portion of the cylinder bore I 2 and serves as a portion of the upper boundary of the clearance space 29.

The size of the plug 23 may vary in accordance with the size and shape of the combustion cham her but it is preferable to have the metal of higher conductivity, of which the plug 23 is formed-constitute those portions of the wall of the combustion chamber which initially embrac that part of a fuel charge which ultimately retivity, such as iron, without causing detonation.

In the form shown in Fig. 3 the combustion chamber wall 22' comprises a composite metal structure having a section 23', substantially iden-'- tical in contour to the plug 23 of Figs 1 and 2, and formed of metal having a relatively high thermal conductivity, such as copper, or a suitable copper alloy or aluminum. Provided in the wall 22 is another section 3| comprising similar metal and provided with a threaded aperture 32 for receiving a spark plug 33. The plug 23' and section 3| are integrally united with the cast iron wall structure of the cylinder head, preferably by hydrogen welding, as set forth above. The relatively high thermal conductivity of the metal of the section 3| surrounding the threaded shank of the spark plug rapidly conducts heat away from the latter and transmits it to the cooling medium adjacent thereto and thereby protects the insulating material of the spark plug 33 from excessive temperatures.

Although but two specific embodiments of my invention are herein shown and described, it will 'be understood that various changes in the size,

shape, and arrangement of parts may be made without departing from the spirit of my invention, and it is not my intention to limit its scope other than by the terms of the appended claims.

What I claim is:

1. In an internal combustion engine cylinder head having a cooling medium chamber, a combustion chamber having a composite wall separating it from said combustion chamber including a copper section having a surface exposed at the interior of said combustion chamber and an opposite surface exposed at the interior of said cooling medium chamber and a section integral with said cylinder head and comprising the same metal as the latter, said copper section substantially providing the part of the wall of said combustion chamber which prior to ignition embraces the fuel mixture included in the last burned portion of a compressed fuel charge.

2. In an engine having a cylinder block provided with a cylinder bore comprising a piston swept portion and a clearance space portion, intake and exhaust valves in said block adjacent said bore, a metal cylinder head on said block having a cooling medium chamber therein and having a combustion chamber extending over said valves and over a portion of said cylinder bore,

a composite wall providing a heat transmitting partition between said cooling medium chamber and said combustion chamber and including in part the same metal as said cylinder head and a section having opposite surface portions exposed at the interiors of said combustion and cooling medium chambers respectively comprising metal having a higher thermal conductivity than the metal of said head, said section providing one bounding side of said clearance space.

3. In an engine having a cylinder block provided with a cylinder bore, intake and exhaust valves in said block adjacent said bore, an iron cylinder head on said block having a cooling medium chamber therein and having a combustion chamber extending over said valves and over.a portion of said cylinder bore and comprising a wall having portions disposed transversely of the axis of said bore and other portions extending substantially in the general direction of the length of said bore respectively, said wall providing a heat transmitting partition between said cooling medium chamber and said combustion chamber including an iron portion formed integrally with said cylinder head and having a 'the interiors of said combustion and cooling chambers respectively and having its edge portions integrally united with the metal surrounding the latter and providing parts of both of said combustion chamber wall portions respectively.

4. In an engine including a cylinder block having a cylinder bore provided with a piston, intake and exhaust valves in said block adjacent said cylinder bore, a cylinder head on said block having a cooling medium chamber and having a combustion chamber extending over said valves and over only a portion of said bore, a composite wall providing a heat transmitting partition between said cooling medium and combustion chambers and comprising sections of metal having different thermal conductivities, the section of metal of higher thermal conductivity bounding the top and sides of the portion of said combustion chamber extending over said bore and having an offset flange extending over the remaining portions of said bore and located in close proximity to said piston when in its outermost position for providing a limited clearance space and having opposite surface portions exposed at the interiors of said combustion and cooling medium chambers respectively.

5. In an engine including a cylinder block having a cylinder bore provided with a piston,

intake and exhaust valves in said block adjacent said cylinder bore, a cylinder head on said block having a cooling medium chamber and having a combustion chamber extending over said valves and over only a portion of said bore, a composite wall providing a heat transmitting partition between said cooling medium and combustion chambers and comprising an iron structure having an opening provided with a copper plug having oppositeside surface portions exposed at the interiors of said combustion and cooling medium chambers respectively, said plug constituting the top and side walls of the portion of said combustion chamber extending over said bore and having an oifset flange extending over the remaining portion of said bore for providing the outer boundary of the clearance space normally provided adjacent said piston when in its outermost position.

6. In an engine having a cylinder block provided with a cylinder bore, a metal cylinder head on said block having a cooling medium chamber therein and having a combustion chamber extending over a portion of said cylinder bore comprising a composite wall having portions disposed transversely of the axis of said bore and other portions extending in the general direction thereof respectively, intake and exhaust valves in said engine registering with a portion of said com-.

bustion chamber, said composite wall providing a heat transmitting partition between said cool ing medium chamber and said combustion chamber and including in part the same metal as said cylinder .head and a section comprising metal having a higher thermal conductivity than the metal of said head, said section including parts of both of said wall portions and being located in the region of the projected area of the outer end of said bore and having opposite surface portions exposed at the interiors of said combustion and cooling medium-chambers respectively;

'7. An engine having a cylinder block provided with a cylinder bore, an iron cylinder head on said block having a cooling medium chamber therein and having a combustion chamber extending over a portion of said cylinder bore, intake and exhaust valves in said engine registering with a portion of said combustion chamber, a wall providing a heat transmitting partition between said cooling medium chamber and said combustion chamber including an iron portion formed integrally, with said cylinder head and having a circular opening substantially concentric with and substantially equal in diameter to said cylinder bore, and a copper plug in said opening having its opposite side surface portions exposed at the interiors of said combustion and cooling medium chambers respectively and having its edge portions integrally united'with the metal surrounding the latter.

8. In an engine including a cylinder block having a cylinder bore provided with a piston, a cylinder head on said block having a cooling medium chamber and having a combustion chamber therein extending over only a portion of said bore, intake and exhaust valves in said engine registering with a portion of said combustion chamber, a composite wall providing a heat transmitting partition between said cooling medium and combustion chambers and comprising sections of metal having different thermal conductivities, the section of metal of higher thermal conductivity having a surface portion exposed at the interior of said cooling medium chamber bounding the top and sides of the portion of said combustion chamber extending over said bore, and having an offset flange extending over the remaining portions of said bore and located in close proximity to said piston when in its outermost position for providing a limited clearance space.

9. In an engine including a cylinder block having a cylinder bore provided with a piston, a cylinder head on said block having a cooling medium chamber and having a combustion chamber therein extending over only a portion of said bore, intake and exhaust valves in said engine registering with a portion of said combustion chamber, a

composite wall providing a heat transmitting parber extending over said bore and having an 75 oflset fiange extending over the remaining portion of said bore for providing the outer boundary of the clearance space normally provided adjacent the said piston when in its outermost position.

10. In an engine having a cylinder block provided with a cylinder bore having a piston swept portion and a clearance space portion, a cylinder head comprising a cooling medium chamber, a combustion chamber having a portion extending over and an adjacent portion extending laterally from said bore, said combustion chamber having a'compositewall separating it from said cooling medium chamber including metals of different thermal conductivities, the section of said wall defining a major portion of one boundary of said clearance space comprising the metal of higher thermal conductivity and having a surface of said metal of higher conductivity exposed'at the inan no; 2,31,11,23.

defining a major portion of one boundary of said clearance space and having surface portions exposed at the interiors of said combustion and cooling medium chambers respectively.

12. In an engine having a cylinder block provided with a cylinder bore comprising a piston swept portion and a clearance space portion, a cylinder head comprising a cooling medium chamber, a combustion chamber having a portion exsection and a section integral with said cylinder head and comprising the same metal as the latter, said copper section defining a major portion of one boundary of said clearance space and having a surface portion exposed at the interior of said cooling medium.

13. In an engine having a cylinder blocl: provided with a cylinder bore comprising a clearance space portion and a piston swept portion having a piston therein, a cooling medium, a combustion chamber having a portion extending over said bore, said clearance space being bounded on one side by said piston when the latter is substantially at its top dead center position, .said combustion chamber having a composite wall separating it from said cooling medium chamber including metals of different thermal conductivities, said clearance space being bounded on its opposite side by a section of said wall being comprised principally of the metal of higher thermal conductivity and having a surface portion exposed at the interior of said cooling medium chamber so as to produce maximum cooling effect on that portion of a fuel charge last to burn.

14. In an internal combustion engine cylinder head, a combustion chamber having a composite wall including metals of different thermal conductivities, the section of said wall that prior to ignition embraces that part of the compressed fuel charge which will be the last to burn being com prised throughout'its thickness of the metal of higher thermal conductivity.

ROBERT N. JANEWAY.

CERTIFICATE OF CO RREC'I'ION,

March 21,. 1939 nosssr N. .JANEWAYI.

:It is hereby-certified'that error appears in'the printed'specificatiion ,cf the above numbered patent requiring correct-ionas follows: Page 1;, second column, line l0, claim 12, after "medium" and before the period, insert chamber; line 11 claim 15, after "medi\ im"- and before the comma, insert chamber; and that the said Letters Patent should be read with this correction therein that the same mayeonform to the record of the case in the Patent Office Signed and sealed this th day of May, a. 9.19 9.

(Seal) Henry Van Ar sdale Acting Gomissioner of Patents.

. said cooling medium chamber including a copper

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