US2366005A

US2366005A - Cylinder head of internalcombustion engines

Info

Publication number: US2366005A
Application number: US414204A
Authority: US
Inventors: Crowe Robert Kelman; Mansell Harvey Charles
Original assignee: Bristol Aeroplane Co Ltd
Current assignee: Bristol Aeroplane Co Ltd
Priority date: 1940-03-01
Filing date: 1941-10-08
Publication date: 1944-12-26
Anticipated expiration: 1961-12-26

Description

Dec. 26, 1944. R, K. CRQWE ETAL 2,366,005

. CYLINDER-HEAD OF INTERNAL-COMBUSTION ENGINES Filed Oct. 8, 1941 2 Sheets-Sheet 1 Dec. 26, 1944. R. K. c RowE ETAL 2,366,005

CYLINDER-HEAD OF INTERNAL-COMBUSTION ENGINES Fi1ed ost. a.. 1941 2 sheets-sheet 2 .fm/@mfom Patented Dec. 26, 1944 HEAD OF INTERNAL- COMBUSTION ENGINES I Robert 'Kelman Crowe and Harvey Mansell, Bristol, England, assignors Bristol Aeroplane Company England, a British company `October 8, 1941,Serial No. 414,204 Great Britain March A3 Claims. ('Cl. 123;-171) Application In I'his invention relates to cylinder-heads'of internal-combustion engines of the air-cooled sleeve-valve type. The cylinder headof a sleevevalve engine comprises a tending into the cylinder and separated from it by a space in which the sleeve rotates and reciprocates, and a circular base-portion extending across the combustion space. The base-portion thus liesat the bottom of a deep recess in the head and, in view of the difficulty of forming cooling fins on the outer surface of the base, it has already been proposed to manufacture the two portions separately and secure them together by screwing one part into the other after the fins have been formed on the base.

In view of the high duty of modern internalcombustion engines, and particularly of aero-` engines, one of the most serious problems is to provide adequate cooling for the cylinder-head, and particularly for the base-portionin heads of the kind described above, and it is an object of the present invention to provide an improved joint between the two portions of the head so as to give improved conductivity Iof heat from the base to the cylindrical portion, and also to give a satisfactorily strong joint.

According to the invention, the two portions of a cylinder-head of an internal-combustion engine of the kinddescribed are lformed with complementary surfaces which interengage by an interference t. The two portions preferably interengage by complementary cylindrical flanges fitted one within the other and, according to another feature of the invention, the engaging surfaces are tapered in such sense as to interlock with one another.

In the accompanying drawings:

Figure 1 is a sectional elevation on the line I-I of Figure 2 of a cylinder-head in accordance with the present invention, and

Figure 2 is a plan of Figure 1, with certain parts omitted.

The cylinder-head comprises a cylindrical portion I having a radial shoulder I I which engages the end of the cylinder. The portion I0 iits Within the cylinder and provides an annular 'space around it to accommodate asleeve-valve. This portion I0 is formed with cooling fins I2, I3 which may be arranged in any desired manner to give an effective dissipation of heat.

In the particular construction shown, the iins l2 extend upwards from the upper surface I4 of the head and downwards in the cylindrical portion I0, and are connected to a more or less cylindrical wall or bale I which partially surcylindrical portion ex- Charles o The Limited, Bristol,

roundsl the space in the middle of the head `in which the sparking-plugs are located by holes 30. A similar construction is provided for the fins I3 which are associated with a baffle IB. With this arrangement, cooling is effected by a flow of air along the top of the cylinder-head from the right-hand side in Figure l, inside the engine-cowling I1, and the baiiie I5 causes this stream to now downwards to the lower part of the head, whence some passes up the central space. around the sparking-plugs to 'cool them and the remainder passes up between the baffle I6 and the adjacent wall around the ns I3. A

` suitable baffle I8 is provided between the upper margin of the ns I2, I3 and the cowling to ensure this direction of flow of the air and baflles 3l (Figure 2) assist in this direction of the airflow.

The base-portion of the cylinder-head comprises a circular plate I9 formed with an upstanding flange or rim 20, and it has formed on it cooling fins 2| which extend parallel with one another across the upper surface of the plate I9, as shown most clearly in Figure 2. The air stream above-mentioned flows between these fins through the head.

The cylindrical portion I0 of the head terminates in a flat annular face 22 which abuts the shoulder surrounding the flange 20, and the internal surface 23 of the part I0 is of complementary shape to the external surface of the flange 20.

The base-portion I9, therefore, is engaged within the cylindrical portion Ill and its engagement is by an interference fit. In the case of a cylinder-head about 6 inches in diameter, the interference is from 0.001 to 0.004` inch, and the assemblage of ing-on process. This can be effected by heating the portion l0 to, say 250 C., or the necessary temperature-diierence can be obtained by cooling the base-portion I9 and heating the cylindrical portion 20.

In order to increase the strength of the joint between the two parts, the internal surface 23 of the part IIl may diverge upwardly in a conical form, the angle of the taper being, for example, 1 so that when assembled the parts are interlocked by a kind of dove-tailed joint whereby separation of the two parts is positively prevented.

It is customary to provide sealing-rings in the cylinder-head `to engage the inner surface of the sleeve-valve, and it is an important feature of this invention that the groove or grooves 24 the parts is effected by a shrinkparts, and the total result is that tliexheatin the contact obtained at the l Y. surface 23 by the interference Iit between the' hottest portion of the head, namely, thebase L9,

is adequately conducted away to the cooling ns 2| and to the cylindrical .body-portion. I0 and j thence to the cooling fins l2, :i3 fromcwhich .it is dissipated in the stream of cooling air. We claim:

1. rIn an air-cooled internalcombustion en gine, a recessed cylinder head comprising a cir-4` cular base formed integrally with closelyl spaced coolingwns extending parallel to one another and .an upstanding peripheral an'ge, a cylindrical bodyportion interengaged tightly 4'with the iiange land formed with radiallyI disposed in- 2. In an air-cooled internal-combustion engine, a recessed cylinder head comprisingl aV cir:

l-indrica'l body-portion cular base formed integrally with closely spaced ooling ns extending parallel to one another from side to side of the base and also formed 3. In an air-cooled internal-combustion engine,.a recessed kcylinder head comprising a cyformed with two sets of radially disposed cooling ns integral with its inner surface, united-at their inner ends by a baffle across-its top` surface; the ange'on `which base is engagedY in the body Withan interference't insuch thatV the two sets of ends of the: i'lns on the base and the ns onf'the baseextend into the body.

l ROBERT KELMAN-CROWE;

HARVEY CHARLES MANSJEJLL.