US2788776A

US2788776A - Detachable cylinder head constructions for liquid-cooled internal combustion engines

Info

Publication number: US2788776A
Application number: US467571A
Authority: US
Inventors: Holt George Allen
Original assignee: Ricardo and Co Engineers 1927 Ltd
Current assignee: Ricardo PLC
Priority date: 1953-11-26
Filing date: 1954-11-08
Publication date: 1957-04-16
Anticipated expiration: 1974-04-16
Also published as: BE533709A; FR1116185A; GB766187A

Description

2,788,776 2R LIQUlD-COOLED' G. A. HOLT CONSTRUCTIONS F MBUSTION ENGINE 3 Sheets-Sheet 1 Attorneys Aprll 16, 1957 DEZTACHABLE CYLINDER HEAD INTERNAL 00 Filed Nov. 8, 1954 ,-April 16, 1957 e A HOLT 2,788,776

DETACHABLE CYLINDER aEAn'coNsTRucTIoN FOR LIQUID-COOLED INTERNAL COMBUSTION ENGINES Filed NOV. 8, 1954 3 Sheets-Sheet 3 U U .I

l I U E Attorneys 1 Unite 7 States Patent DETACHABLE CYLINDER HEAD CONSTRUC- TIONS FOR LIQUID-COOLED INTERNAL COMBUSTION ENGINES George Allen Holt, Shoreham-by-Sea, England, assignor to Ricardo & Co., Engineers (1927) Limited, London, England, a company of Great Britain Appiication November 8, 1954, Serial No. 467,571

Claims priority, application Great Britain November 26, 1953 10 Claims. or. 123-4132 This invention relates to detachable cylinder head constructions for liquid cooled internal combustion engines of the poppet valve type.

For convenience herein it will be assumed that the cooling liquid is water since this would normally be the case, which term, when used herein, is therefore, to be understood as including other cooling liquids.

Difliculty is often experienced, particularly in poppet valve internal combustion engines of the liquid fuel injection compression ignition type, and other internal combustion engines in which the cylinder head is subject to high mechanical stresses due to the working fluid pressure and to high thermal stresses, in maintaining satisfactory cooling and satisfactory joint between the cylinder head and cylinder or cylinder block, the most usual breakdown in this joint being gas leakage or even the blowing-out of a section of the gasket due to pressure between the gasket and the cylinder and the cylinder head faces being or becoming locally insuflicient. The difliculty of preventing local thermal distortion tending to cause such breakdown is moreover increased in many cases by the comparatively complex structure of the cylinder head necessary to provide therein inlet and exhaust ports and passages and/or an appropriate combustion chamber, pocket or recess and a sparking plug or fuel injector boss and the necessity of ensuring adequate and suitably distributed cooling.

Various expedients have been tried to overcome the difiicul'ty of maintaining a satisfactory joint between the cylinder and cylinder head, including the use of relatively thick gaskets, in an attempt to equalise the pressure over the faces of the gasket and even the use of gaskets of graded thickness in order to maintain adequate pressure on the gaskets between the co-operating faces of the cylinder head and cylinder over the necessary areas. The use of thick gaskets,"however, or of gaskets of graded thickness tends to cause distortion of the cylinder head when the holding-down nuts or the equivalent are tightened down since, in the case of thick gaskets, the gasket tends to become highly compressed in the area adjacent tothe holding-down nuts or the equivalent while the other parts of the gasket exert such separating forces on the areas more remote from the holding-down nuts as to distort the cylinder head face, while in the case of gaskets of graded thickness the thicker parts of the gasket tend to exert higher separating forces on the parts of thesurfaces with which they engage and thus similarly tend to cause distortion, v j

The use of thick gaskets also tends to increase the area of the gasket which is subject to the working fluid pressures and thus to some degree to increase the tendency for the gasket to blow out, while the manufacture of gaskets of graded thickness is an awkward operation and requires a special manufacturing and control technique apart from the experimental work required to find out precisely how to arrange the grading in thickness.

It will be appeciated that in the case of cylinder heads for engines of the overhead valve type, any distortion of I ice the cylinder head is particularly undesirable since it tends to result in distortion of the valve seats and hence improper seating of the valves with its attendant undesirable results.

An object of the present invention is to provide an improved form of detachable cylinder head construction for water cooled internal combustion engines of the poppet valve type which will tend to facilitate the making and maintaining of a fluid-tight joint between the co-operating surfaces of the cylinder head and cylinder with the use of a normal gasket of substantially even relatively small thickness throughout its area and without distortion of the cylinder head while providing for adequate cooling of the required parts of the head.

A water cooled cylinder head construction for an internal combustion engine of the poppet valve type according to the present invention comprises an inner wall or deck arranged to engage, with the interposition of a gasket, the face of the cylinder around the chamber which is subject to working gas pressure during the working stroke, an outer water retaining wall which with the inner wall forms a cooling water chamber for the cylinder head, and a buttress wall which is integral with the inner wall and, when viewed along the cylinder axis, lies closely around the periphery of the chamber subject to working gas pressure and is arranged to be acted upon by holding down nuts or the equivalent at spaced points in its peripheral length, the structure including at least one inlet passage for the delivery of cooling water into the space surrounded by the buttress wall and at least one transfer or outlet passage for the outflow of cooling water leading from this space so that a stream or streams of cooling water will be directed through the space surrounded by the buttress wall. 7

in many cases the cooling water inlet passage or each of such passages will lead into the space surrounded by the buttress wall from a part of the cooling water chamber lying outside this wall, while similarly, the cooling water outflow passage leading from the space surrounded by the buttress wall will lead into another part of the cooling water chamber lying outside the buttress wall. In other cases, however, as for example in the case of a side valve engine the cooling water outflow passage may lead directly from the space surrounded by the buttress wall into a collecting channel formed in the upper outer wall of the cylinder head.

It will be apparent that, with the present invention the holding down nuts or the equivalent act in elfect through the buttress wall directly on the inner wall along a line (hereinafter called the pressure line) closely surrounding the chamber which is subject to working gas pressure during the working stroke, thus holding firmly in contact with the gasket along this pressure line the co-operating faces of the cylinder head and cylinder to ensure a gas tight joint around the chamber and prevent the gasket blowing out. The arrangement also provides for the delivery of cooling water in a desirable manner through the chamber surrounded by the buttress wall, that is to say over the parts of the cylinder head structure which tend to be subject to the highest mechanical and thermal stresses, in a manner which tends to prevent hot spots. The gasket can moreover also be satisfactorily thin so that distortion even of parts of the head outside the pressure lines tends to be avoided.

It is to be understood that, whiie the edge of the buttress wall Where it springs from the inner wall should be substantially continuous around the periphery of the chamber which is subject to working gas pressure, the buttress wall may have cut-away parts along its other edge or elsewhere provided that the construction is such that the downward forces exerted by the holding down nuts or the equivalent on the buttress wall will be trans- 3 mitted through the buttress wall along substantially the whole of the pressure line referred to.

The invention may be applied to single cylinder engines,

, which term may for this purpose be regarded as including engines in which each individual cylinder or cylinder bore has its own individual cylinder head, or to multi-cylinder engines in which a cylinder head is applied to a cylinder block containing two or more cylinder bores.

The invention may be applied to engines of the side valve type or of the mixed side valve and overhead valve type or of the overhead type and three examples of the invention are shown in the accompanying drawings, in which:

Figure l is a sectional side elevation on the line I-I of Figure 3 of a cylinder head and the upper end of the associated cylinder of a single cylinder engine of the compression ignition liquid fuel injection type incorporating the invention;

Figure 2 is a cross-section on the line IIH of Figure 1,

A Figure 3 is a cross-section on the line III-III of Figure 1, a

Figure 4 is a similar view to Figure 1 through one cylinder of an alternative construction of two cylinder engines according to the invention in the plane IV-1V of Figure I Figure 5 is a cross-section on the line VV of Figure 4, i

Figure 6 is a sectional side elevation on the line VIVI of Figure 7 through one cylinder of a multi-cylinder side valve engine according to the invention, and

Figure 7 is a cross-section on the line VHVII of Figure 6.

In the construction shown in Figures 1, 2 and 3 the engine is of the liquid fuel injection compression ignition .type and comprises a water cooled cylinder block A containing water cooled liner B forming the cylinder bore B the upper end of the cylinder block being provided with the usual flat surface B on which is to be seated a cylinder head, indicated generally at 'C with the interposition of the usual gasket D.

The cylinder head C which is in accordance with the present invention, comprises an inner wall or deck C the lower face of which engages the gasket D and extends over the cylinder bore, an outer wall C which is united around its edge of the inner wall by a surrounding wall C so as to enclose a water chamber, inlet and exhaust passages E and F communicating with inlet and exhaust ports in the inner wall and extending, as shown, through the space between the inner and outer walls to inlet and exhaust openings E F in the surrounding wall C these passages E and F being provided with the usual valve guide bosses, one of which is shown in Figure l at E through which pass the stems of the poppet valve by t which the ports are normally closed. In addition the cylinder head is formed with a combustion pocket C of well-known form having a hemispherical upper portion C while its lower cylindrical portion is formed to receive a hot plug G having limited contact with the surrounding cooled wall and containing a tangential passage G by which gases can flow to and fro between the pocket and the cylinder bore. Between the pocket and the upper Wall extends a boss C 'for a fuel injection device of usual type. As will be seen most clearly in Figures 2 and 3 the cylinder head also includes a buttress wall H which springs from the inner wall C and lies around the cylinder bore,

7 this buttress wall being united at the appropriate points to the wall of the pocket C so that the outer part of this wall indicated at C in Figures land 2 forms in effect a part of the buttress wall which viewed in plan may therefore be regarded as substantially completely surrounding the chamber which contains the working gas under pressure. Spaced around the buttress wall H and extending between the inner and outer walls are a series of hollow bosses H through which will pass screw h e d and lower wall-s N, N

studs secured to the cylinder block in the usual manner and serving by means of nuts on their outer ends to clamp the cylinder head firmly into engagement with the cylinder. It will be noted that the part of the buttress wall constituted by the portion C of the pocket wall has two of the bosses H in question associated therewith while in addition there are two further hollow bosses forstuds formed at H on the surrounding wall.

Formed in the inner wall C at points outside the but-f tress wall H are cooling liquid inlet ports K, K? leading from the cooling jacket of the cylinder into parts of the water chamber of the cylinder head which lie outside the buttress wall H. The passage K leads into a chamber K out of which leads a cooling water inlet passage K into the chamber surrounded by the buttress wall. A deflecting lip K is associated with the port K and is formed so as to tend to cause the cooling water flowing through the port K to be divided into three streams one of which flows in between the inlet and exhaust passages E and F while the others flow outwards round these passages. Flow also takes place through the ports K into chambers K and thence through further cooling water inlet passages K into the parts of the chamber surrounded by the buttress wall H lying on the outer sides of the inlet and exhaust passages. The arrangement is such, as will be most clear vfrom Figure 3, that after flowing past the inlet and exhaust passages E and F the cooling water is caused to flow round the combustion chamber pocket C through cooling water outlet passages formed by appropriate cutaway portions of the buttress wall H and finally to an outlet port L in the wall C on the side of the cylinder head remote from the passage K; 7

Thus a flow of cooling water, such as to provide adequate cooling for the parts of the cylinder head subject to high mechanical and thermal stresses adjacent to the inlet and exhaust ports and around the adjacent part of the combustion chamber pocket tends to be obtained.

In the alternative construction shown in Figures 4 and 5 the engine is of the liquid fuel injection compression ignition type and has two cylinders formed in a watercooled cylinder block M provided with two liners M containing the actual cylinder bores, the block having the usual fiat surface on its upper face. on which is seated a cylinder head with the interposition of the usual gasket M In the construction shown the cylinder head according to the invention comprises the lower wall or deck N the lower face of which mates with the gasket M, an

' upper wall N spaced from the lower wall and surrounding wall N uniting the peripheral edges of the upper Also formed in the head so as to lie between the walls N and N are exhaust passages N terminating at their inner ends in exhaust ports N lying respectively over the two cylinder bores and arranged to be controlled by poppet valves and a common inlet passage N terminating in inlet ports N also lying over the cylinder bores and arranged to be controlled,

by poppet valves in the usual manner. The bosses for containing the usual valve guides for the poppet valves in question are shown at N".

Also formed in the cylinder head adjacent to each cylinder bore is a combustion chamber pocket N having a flattened dome shaped inner end and an approximately cylindrical mouth in which lies a plug 0 having'limited contact with the surrounding walls and containing pasa sages 'indicatedxat O for the flow of gas between the interior of the pocket and the cylinder bore.

Extend ing' between the upper and lower walls N, N are also oval channels of known general form indicated at N forthe passage of the push rods of valve operating since it forms no part of the invention.

Formed integral with the lower wall N and, viewed 11in plan, extending closely around eachv of the chambers agasam 5 which contains working fluid under-pressureduring the working stroke, is a but-tress walk-indicated at-'P,ipart-1of this buttress wall being "formed by the vportion C) of the combustion chamber pocket. Each buttress wall where it meets the inlet and exhaust passages N N extends around the undersides of such passages as indicated in dotted lines in Figure 5 while the upper edges of the other parts of the buttress wall lie clear of the upper wall N Extending between the upper wall of the pocket N and the upper wall N in the manner indicated in Figure 5 is a V-shaped wall close tothe apex of which is formed a cooling water transfer passage 0 shown most clearly in Figure 4. Associated with each buttress wall are bosses P through which pass the usual holding down studs for receiving nuts by which the cylinder head is clamped to the cylinder block as shown at P in Figure 4.

Extending between the outer side of each combustion chamber pocket N and the surrounding wall N is a hollow boss 0 to receive a fuel injection device 0 as shown in Figure 4, and in the part of the wall N immediately below each of these bosses is formed a port Q communicating with the water jacket of the cylinder block M for the passage of water into the cooling spaces of the cylinder head. Each of the ports Q thus opens into a chamber formed by one of the V-shaped walls 0 Water outflow ports N are formed in the surrounding wall N as shown in Figure 5.

During operation water flows upwards through each of the ports Q and, after flowing round the boss 0 in which the fuel injection device D is located, flows over the top of the adjacent pocket N and then downwards through the passage 0 so as to be directed over the part of the upper face of the lower wall or deck N adjacent to the inlet and exhaust ports and the wall of the combustion chamber pocket, whence it flows around these ports in the manner generally indicated by arrows in Figure 5 partly under and partly around the exhaust passage N and thence out through the adjacent outlet port. I

'It will be seen that the holding down nuts acting on the upper ends of the bosses P transmit a force through the bosses and the buttress walls P tending to maintain in close contact with the gasket M the parts of the lower wall N immediately below the buttress walls thus ensuring as far as possible the maintenance of a seal between the cylinder head and cylinder block around the chamber in which the working gases are under pres sure during the working stroke.

In a modification, one or more additional ports may lead from the water pocket of the cylinder block M into the water space in the cylinder head as indicated for example in dotted lines at Q in Figure 5.

In the further construction illustrated in Figures 6 and 7 the engine is of the vapourized charge spark ignition type and comprises a cylinder block R of conventional water cooled type containing inlet and exhaust ports R arranged to be controlled by poppet valves in conventional manner, the upper .face of the cylinder block being flat and formed to have clamped thereto, with the interposition of the usual gasket S, a cylinder head. The cylinder head comprises a lower wall or deck T, an upper wall T and a surrounding wall T connecting the peripheral edges of the upper and lower walls. The cylinder head is also formed with a combustion chamber recess T of well known form overlapping the cylinder bore and provided with a sparking plug boss T which unites it to a depressed portion of the upper wall T Formed in the upper wall T is a water outlet passage or channel T also of conventional form while the lower wall T is provided with ports T which communicate with the water jacket of the cylinder R through ports R and serve for the admission of cooling water to the cylinder head cooling spaces.

Formed integral with the lower wall T are buttress common to adjacent working pressure chambers.

walls indicated atU unitedtospaced bosses U which extend betweenvthe upper and lower walls T and T and serve to receive studs for nuts by which the cylinder head is clamped to the cylinder block as shown in Figure 6'. As will beseen from Figure 7, the buttress walls are so arranged that viewed in plan each of the chambers within which .ga'scs under pressure exist during the working stroke of a piston is closely surrounded by a buttress wall, parts of the buttress walls indicated at U being Each of the water inlet ports T' communicates with a chamber V from which leads a water inlet passage V directed towards the adjacent sparking plug boss T Thus, during operation water flowing through the port T into the chamber V is directed by the passage V over and around the sparking plug boss T into the chamber surrounded by the appropriate buttress wall and over the top of the pocket T This water by reason of its momentum of flow flows across the top of the cylinder head into the area remote from the water inlet ports V and then escapes through the Water outlet passage T in usual manner.

It will readily be understood that although in the construction shown by way of example in the accompanying drawings, the cooling water is delivered to the cylinder head from the cylinder block, the invention is applicable to arrangements in which some or all of the cooling water for the cylinder head is delivered directly thereto without passing through the cylinder block.

What I claim as my invention and desire to secure by Letters Patent is:

1. A water cooled cylinder head construction for an internal combustion engine of the poppet valve type comprising an inner wall or deck arranged to engage, with the interposition of a gasket, the face of the cylinder around the chamber which is subject to working gas pressure during the working stroke, an outer water-retaining wall which, with the inner wall, forms a cooling Water chamber for the cylinder head, and a buttress wall which is integral with the inner wall and extends in a direction substantially parallel to the cylinder axis and, when viewed along the cylinder axis, lies closely and substantially completely around the periphery of the chamber subject to working gas pressure and immediately opposite parts of the face of the cylinder, and is formed at spaced points in its peripheral length to receive threaded means acting thereon to clamp the cylinder head against the cylinder, the structure including at least one inlet passage for the delivery of cooling water into the space surrounded by the buttress wall while at least one transfer passage for the outflow of cooling water leads from this space so that a stream or streams of cooling water will be directed through the space surrounded by the buttress wall.

2. A cylinder head structure as claimed in claim 1 in which the structure includes inlet and exhaust ports in the inner wall or deck, inlet and exhaust passages leading from the inlet and exhaust ports through the space surrounded by the buttress wall, and in which the inlet and transfer passages through which water enters and leaves said space are disposed so that a relatively rapid flow of water takes place over the parts of the deck and the parts of the inlet and exhaust passages adjacent to the ports.

3. A cylinder head structure as claimed in claim 2 in which the disposition of the inlet passage by which water enters the space within the buttress wall causes a substantial proportion of the water to be directed onto the parts of the deck and of the inlet and exhaust passages adjacent to and around the ports.

4. A cylinder head structure as claimed in claim 2 in which the structure includes a combustion pocket having a mouth opening through the deck and in which an inlet passage (which may be the said inlet passage) is disposed to direct water on to that part of the deck within the buttress wall which is situated between the inlet and exhaust ports and the wall of the said combustion pocket.

' 5. A cylinder head structure as claimed in claim 2 including a combustion pocket having a mouth opening through the deck, a plug disposed within the mouth of the pocket and largely heat insulated from the wall of the pocket, and in which inflow and outflow passages for the flow of cooling water respectively into and out of the space surrounded by the buttress wall are disposed to cause water 'to flow over parts of the deck and of the inlet and exhaust passages adjacent to the ports and then over the wall of the pocket before entering the water outflow passage.

6. A cylinder head structure as claimed in claim 1 for a side valve spark ignition engine including a spark plug boss and an inflow passage by which cooling water enters the space within the buttress wall and is directed around the sparking plug boss.

7. A cylinder head structure as claimed in claim 1 including tubular bosses to receive studs for holdingdown nuts, such bosses extending between the inner and outer walls, with the various sections of the buttress wall extending'between the tubular bosses, the said parts of the buttress wall which extend between the tubular bosses being integral with the inner wall but spaced from the outer Wall. r

8. A cylinder head structure as claimed in claim 7 in which the structure includes inlet and exhaust ports in the inner wall, or'deck, inlet and exhaust passages Ileadingfrom the inlet and exhaust ports through the space surrounded by the'buttress wall, and in which inflow and outflow passagesthrough which water enters and leaves said space are disposed so that a relatively rapid flow of water takes place over the parts of the deck and the parts 'of the inlet and exhaust passages adjacent to the ports. 7 1

9. A cylinder head structure as claimed in claim 1 fora multi-cylinder internal combustion engine in which the buttress walls associatedwith a pair of adjacent cylinders include a common section of buttress wall lying between the working pressure chambers associated respectively with the two cylinders.

10. A cylinder head structure as claimed in claim 1 in which'an inflow passage has its entry end'opening through the inner wall to receive water from the water jacket of an associated cylinder block to which the cylinder head is secured.

References Cited in the fileof this patent UNITED STATES PATENTS Hesselman Aug. 18, 1914 1,331,420 Diamond Feb. 17, 1920 1,792,867 Radford Feb. 17, 1931 1,998,706 Campbell Apr. 23, 1935 Anderson et al. May 11. 1943