US2205646A - Cylinder head - Google Patents

Description

CYLINDER HEAD Filed Jan. 20, 1958 2 sheets-sheet 1 rf//l/ f ATTORNEYS June 25, 1940. E. G. FAHLMAN 2,205,546

CYLINDER HEAD Filed Jan. 2o, 1938' 2 sheets-sheet 2 Z 5 0 n 6 l 6 Jlau 0 a O 5l G ,./5 H(6 .m 6 755 3 h 2 Z 5 l a 0 5 6 El?, F 9 RJ ,.Md, R .d 4 5 .y/f/ .1 0G a .4 l l 5. T t 7 o o 1 6 x ,.7F ma mtl 7 4 ,l n a.. w45, V# .w 0 .1 L 3 0 y 5, EM xo o e O \0 5 :05 7% \5 6 ,6x 4 6 8 x 5 )L W .MW 5M, x4 x5 \N 1.. Z` Y #l 4 :Jn/v U3 4 o F 74 l L) .1 50. 8 6.9 Z F 2 5 5 118 w Jil 0 O l 5 a mi, E 04u 6 4. 1 4 04 l/um M f, ,1 5 4 AM .1 .w 79 o 5 Z .L 6 1/ flo 44%5 v6 Z/v 5 9 4 M 3 G H 6 4 rll 5\ Af/JA a 7 2J n4/ \\\/4 o1 6 Z 5 f/ 5 F 4 5 5 .L 0 54 v. G O 5 ./5 Z 6 6 0 Z o/O ./a 9 5 6 ATTORNEYS Patented `lune 25, 1940 PATENT OFFICE CYLINDER HEAD Everett G. Fahlman, Lakewood, Cleveland, Ohio, assignor to The Permold Company, Cleveland, Ohio, a corporation of Ohio Application Januaryv 20, 1938, Serial No. 185,881

. 1.0 Claims.

l This invention relates to liquid cooled cylinder heads for internal combustion engines and has for its principal object the provision of such a head of new and improved design and construction which will permit a more desirable and eincient operation of an engine and is simple and inexpensive to manufacture.

Another object is to provide acylinder head having a compression wall overlying a combustion chamber and a cooling liquid chamber over n the compression wall with means to reinforce the head against deflection, whereby the compression wall may be relatively thin.

Another object is to provide a means for reinforcing a cylinder head which does not objectionably interfere with the flow of cooling liquid through the cooling liquid chamber and which is adapted to various designs of cylinder heads in order to furnish reinforcement at any region subject to strain.

Another object is to provide a cylinder head having a wall overlying a combustion chamber and an outer wall separated therefrom by a cooling liquid chamber with a reinforcing means associated with the vouter wall and arranged to strengthen the wall voverlying the combustion chamber.

The usual method of attaching a cylinder head to the cylinder block of an engine is by means of a plurality of cylinder head bolts whichv pass through the cylinder head and are secured in the cylinder block. The explosion of a combustible mixture in the cylinder and combustion chamber of an internal combustion engine subjects the head thereof to considerable strain. One effect of an explosion in the combustion chamber is to cause the portion or portions of the cylinder head lying between the bolts securing the head to the engine block to be deflected.

Such repeated deflection is very undesirable in those portions of the cylinder head which are disposed between adjacent cylinders becauseit is likely to result in blow-by or passage of gases from one cylinder to another. Furthermore, the repeated deflections, particularly in` water jacket. However, a gasket is usually insufficient to maintain the combustion chamber in a sealed condition when deflection of the cylinder head occurs under the high pressures of the explosion. Leakage of the combustion gases 5 from the combustion chamberbetween the cylinder head and the top surface of, the engine block often occurs at points intermediate the hold-down bolts. This escape of gaseous products of combustion is commonly referred to as 1o blow-by, mentioned above. Such a condition is undesirable, it interferes with the performance of an engine because of the loss of power involved and if continued for a sufiicient period of time causes erosion or corrosion of the metal of the l5 cylinder head or engine block or both. Additionally, it may result in loss of liquid from the cooling system.

In order to minimize deflection of the lower or compression wall of a cylinder head it is cus- 2'0 tomary to increase the thickness of such wall. This practice, however, is objectionable because of the increased weight of the cylinder head necessitated by the increased thickness of the cross-section and additional metal used to form 25 the head.

With an increase in the compression ratioy of an internal combustion engine the diiculties encountered as a result of deflection of the lower or compression wallrof the cylinder head, such 30" as blow-by and cracking thereof over the combustion chamber, are increased. Consequently, it is of paramount importance to perfect a cylinder head design which minimizes deflection of the lower or compression wall. Because of the 35 increased use in cylinder heads of metals of relatively high heat conductivity, such as aluminum and copper which are relatively expensive, it is desirable that the strengthening of the lower wall of the cylinder head be accomplished 40 without resorting to excessive increases inthe thickness thereof and the present invention reshown in Fig. 1; 55,l

Fig. 4 is a sectional view taken on the line 4-4 of Fig. l;

Fig. 5 is a sectional View taken on the .line 5*-5 of Fig. 1;

Fig. 6 is a sectional view taken on the line G-G of Fig. l;

Fig. '7 is a sectional view taken on the line Z`-`f of Fig. 1;

Fig. 8 is a plan view of a cylinder head for six-cylinder engine block constructed in accordance with the present invention;

Fig. 9 is an elevational view partly in section on the line 9-9 of Fig. 3;

Fig. l0 is a bottom View of the cylinder head shown in Fig. 8;

Fig. ll is a section on the line Iie-ii of Fig. 8;

Fig. 12 is a sectional view on the line |2|2 of Fig. 8; and

Fig. 13 is a sectional. View with parts broken away on the line |S|3 of Fig. 8.

Referring to Figs. l. through 7 by numerals of reference, which indicate like parts throughout the several views, the cylinder head comprises a top wall indicated generally by the numeral I0 and a bottom wall indicated generally by the numeral 2E). The cylinder head is arranged and intended to be applied to the engine block (not shown) of an internal combustion engine so that each of the depressions or concavities 2| formed in the lower wall of the cylinder head will overlie a cylinder and inlet and exhaust valves to form a combustion chamber. Portions 22 of the bottom wall of the cylinder head which surround the concavities 2| lare formed to lie in close proximity to the top surface of the engine block, so that by suitable means such as a gasket (not shown) positioned between the portions 22 of the cylinder head and the engine block each of the combustion chambers, including the concavities 2|, are sealed from each of the other concavities and combustion chambers, and from the atmosphere and the cooling liquid passages.

Marginal stud bosses 3|, located at peripheral portions of the cylinder head, and central stud bosses 32, are provided at suitably spaced intervals around and across the cylinder head. These stud bosses have central apertures 33 to receive suitable bolts or studs (not shown) which are secured in the engine block and fasten the cylinder head to the engine block.

The top wall ID is spaced from the bottom or compression wall 20 and marginal portions I I of the top wall are curved or otherwise formed to join with the bottom. wall 2U to provide an enclosed cooling liquid chamber I2. A number of liquid inlet openings 26 are formed in the bottom wall 2Q and arranged to communicate with suitable passages in the water jacket of the cylinder block to provide a supply of cooling liquid to the cooling liquid chamber I2 of the cylinder head. All of the stud bosses 3| and 32 extend entirely through the cylinder head and are clamped rigidly to the engine block by tightening of the cylinder head bolts. Those stud bosses positioned in intermediate portions of the cylinder head and extending through the cooling liquid chamber I2 are relatively long and have intermediate portions 38 exposed to the cooling liquid. Some of the marginal stud bosses may be relatively short since the cooling liquid chamber I2 may not extend to all portions of the cylinder head. Portions of the top wall I D overlying the concavities 2| are formed to join with the bottom wall 20 to provide spark plug bosses I3 which are thus surrounded by the cooling liquid chamber.

As previously mentioned, the effect of the high pressures due to explosions in the combustion chamber of the internal combustion engine is to cause a defiection of portions of the lower wall 2|). The amount of deflection of portions 23 which lie substantially close to stud bosses is relatively small, whereas the portions of the bottom or combustion Wall 20 which are relatively removed from the support afforded by the stud bosses usually exhibit a greater deflection. For example, the portions 24 of the bottom wall 20 which form parts of the concavities 2| are relatively far from the support of stud bosses and in the absence of reinforcement would normally be subject to considerable deiiection.

In the operation of an internal combustion engine where such deflection is intermittent, there is a marked deleterious effect on the ma terial of the cylinder head which often results in its cracking, or other failure. If deflection occurs in the bottom wall 20 at the portions` 22 which lie marginally of a concavity 2| then the gaseous products in the combustion cham ber, which are under high pressure, are likely to escape therefrom between the cylinder head and the cylinder block notwithstanding the gasket, since the latter is ineffective to seal the joint between the engine block and the cylinder head when the bottom wall of the latter is excessively deiiected. This blow-by or escape of the gases from the combustion chamber causes a loss of power in the engine and erosion or corrosion of the metal thereof andis otherwise objectionable.

In accordance with the present invention, a post or pillar 40 is formed to extend between the bottom wall 2D and top wall ID through the cooling liquid chamber I2. In this manner the bottom wall 20 is reinforced or strengthened by the top wall I0 so that in effect the resistance of the bottom Wall to deflection is substantially equivalent to that of the combined strength of the bottom wall plus the top Wall. Preferably the post or pillar 4D is positioned adjacent a portion 24 of the bottom wall so that it will reinforce that part most subject to excessive deflection.

Reinforcing members or ribs 4| are formed in association with the top wall IU and materially increase its strength and resistance to bending. The stud bosses 3| and 32, being relatively rigidly secured to the engine block by the hold-down bolts, form convenient supports for the ribs 4I.

Accordingly, it is desirable that the ribs extend between stud bosses and preferably are formed exteriorly of the top wall I0 as shown in Fig. 6. Such a method of construction has a number of advantages. One such advantage is that the cooling liquid chamber is substantially unobstructed so that the reinforcing rib does not interfere with the iiow of the cooling liquid through the cooling chamber. Thus the top wall I0 can be constructed to lie in much closer proximity to the bottom wall 20 so as to provide a relatively thin cylinder head to obtain a desirable, efficient ow of the cooling liquid therethrough. In addition, a thin cylinder head may be constructed of substantially less amount of material than is used in a thick cylinder head, and, accordingly, is more economical to manufacture.

It is desirable that the ends of the ribs 4| have an adequately strong connection to the stud bosses. Consequently, in the event that the stud bosses do not extend a sucient distance above the top vwall l of the cylinder head it is desirable that end portions 42 of the ribs be formed belowv the top wall IIJ of the cylinder head in the cooling liquid chamber I2 and joined to the stud bosses. Thus, in effect, a strengthen- 'ing member or rib is provided which extends across the top of the cylinder head with end portions extending below the top wall thereof and securely xed to the stud bosses and having a central portion positioned exteriorly of the of the rib 44 extending between the central stud boss 34 and marginal stud boss 3E. Preferably the intersection 45 of the ribs 43 and ill is arranged to lie directly over the pillar 40 extending between the top walll and bottom wall 2G of f the cylinder head. In this manner the compression wall of the combustion chamber of the engine is directly supported by the ribextending between stud bosses on the top of the cylinder head, and the strain due to explosions inA the combustion chamber are more effectively transmitted directly to the stud bosses and hold-down bolts.

In asimilar manner each ofthe posts or pillars 40 which is arranged to strengthen a portion 24 of the bottom wall 2l] overlying a combustion chamber of the engine is positioned so as to underlie the intersection of strengthening ribs 4I which extend across the top wall lll of the cylinder head between stud bosses. Accordf ingly, the compression wall of the cylinder head overlying each of the combustion chambers is strengthened against objectionable deflection so that a more efficient and desirable operation of the engineresults and the cylinder head is less sub-ject to deterioration. In addition to the pillarsv 4D extending tothe bottom `wall 20 of the cylinder head from the intersection 45 of the ribs 4l, auxiliary posts or pillars 4B are provided to reinforce the marginal portion 25 of the bottom wall 2B of the cylinder head which is adjacent the concavities 2| of the combustion chambers of the two middle cylinders. These auxiliary pillars 46 are' supported by two of the centrally extending ribs 4l which are joined to a central stud boss. indicated by the numeral 49.

Thus the marginal portions 25 of they bottom wall of the cylinder head are reinforced against excessive deflection so that blow-by-between the combustion chambers and water jacket is minimized. l

This strengthening of the cylinder head by means of ribs formed exteriorly of the top or outer wall of the cylinder head is of such beneflcial effect that the thickness of both the top wall Il) and bottom wall 20 may be materially lessened without objectionably affecting the efflciency of the cylinder head. Accordingly, an

appreciable economy may be realized in the manufacture of cylinder heads by employing the For example, the rib 43 Also, the bottom wall 20, strengthened by the pillars 40 and 46 from the ribs 4I, need not be as thick as would'be necessary in the absence of the ribs. Furthermore, this thinning or reduction of thickness `of the lower wall 20 enables a more efficient transfer of heat from the combustion chamber of the engine to the cooling liquid chamber I2 of the cylinder head.

Another feature of a cylinder head constructed in accordance with the present invention relates to the casting of such a cylinder head in a chill or permanent mold or a sand mold having chills in association therewith. Because of the relatively thin cross-section of each of the ribs 4I and because of their formation on the exterior of the cylinder head, where substantially their entire surface can be arranged in contact with the metallic mold section of a permanent or semi-permanent mold or with a chill of a sand.

mold, such ribs may be quickly solidified in the casting operations toproduce a desirable crystalline structure in the metal or alloy from which the cylinder head is cast. Accordingly, the ribs 4l are of increased strength relative to the quantity' of metal used and the cylinder head is t'hus stronger and lighter than those constructed according to usual design.

As previously mentioned, the absence of strengthening ribs within the cooling liquid chamber I2 permitsthe use of a relatively thin headA in which the cooling liquid chamber is relatively shallow, so that no deep pools of cooling liquid form and a' proper flow of the cooling liquid may be obtained and regulated as regards kvelocity and direction of flow. Thus the cooling liquid may sweep over the bottom wall 28 of the cylinder head from the liquid inlet passages 25 to the cooling liquid outlet i4.

The strengthening ribs former in association with the top or` outer wall I!) of the cylinder head may be `arranged in various positions according to the requirements of any particular design. For example, the ribs may be located 'as shown on the cylinder head illustrated in Figs.

8 through 13. This head is designed for application to an internal combustion engine cylinder block having six cylinders and cylinder head parts previously described in connection with the cylinder head illustrated in Figs. 1 through 7 have been indicated by the same numerals of reference. It is proposed that the thickness of the topi wall Hl of this cylinder head be constructed considerably thinner than that which ordinarily would be requiredl inthe absence of the use of the strengthening ribs provided by the present invention. Accordingly, in order to give sufcient strength to the cylinder head a plurality of peripheral ribs 5!) arev provided. These ribs in effect provide a substantially continuousrib extending about the peripheral portions of the cylinder head between the marginal stud bosses 3l. l l

In an internal combustion engine with which the cylinder head illustrated in 8 to I3 may be used the cylinders may be offset substantially with respect to the spark plug bosses i3 so that thefprojection ofthe cylinder walls would appear as the broken line circles 27 on the bottom Wallv 20 of the cylinder head, (see Fig. l0). This offset of the valves and'spark plugs with respect to the" cylinder, which occurs in what is commonly referred to as anL-head engine, necessitates a` relatively elongated combustion chamber. The combustion chamber is formed by the recessedor concave portion 2l of the bottom of the cylinder head and the upper or compression end of the cylinder which is overlaid by a portion of the bottom wall 2i) of the cylinder head. Because of the relatively large area of the bottom wall 2li of this cylinder head exposed to the high pressiues of explosions in the combustion chambers, auxiliary posts or pillars are formed between the top wall i6 and bottom wall 2li through the cooling liquid chamber These pillars are supported by the auxiliary ribs which extend between successive stud substantially through the central portion of the cylinder head.

The pillars 40 which reinforce the compression walls of the cylinder head are variously supported. In each case, however, these pillars extend between the top wall ifi and bottom Wall EB through the cooling liquid chamber i2. The compression walls of the cylinder head which overlie the cylinders at each end of the cylinder head, have posts or pillars ill supported by'cross ribs 5i and E52, rib El extending from a marginal stud boss El? positioned in the corner of the cylinder head to a central stud boss 6i. lThe ribs 52 extend between marginal stud bosses 62 positioned centrally in each end of the cylinder head and marginal stud bosses $3 which are positioned between the end cylinders and the nent adjacent cylinders. The pillars 46 extending between the top and bottom walls overlying the end combustion chambers preferably are positioned beneath the intersection 53 of the crossribs 5i and 52.

The pillars fill, to strengthen the walls of the cylinder head overlying the combustion chambers ci the cylinders next adjacent the end cylinders, are supported by supplementary ribs 511 which are formed exteriorly of the outer or top wall lil of the cylinder head, and extend between a central portion of peripheral ribs 5B and auxiliary ribs lil'. Thus the rib design over each of the cylinders next adjacent the end cylinders is in the form of an H, the supplementary ribs 54 being carried by the peripheral and auxiliary ribs with which they intersect and indirectly carried by the stud bosses which carry the peripheral ribs 5D and auxiliary ribs 41.

Each of the pillars lll which strengthen the combustion walls overlying the two central cylinders is supported by a tln'ee-membered rib. One member 55 extends longitudinally of the cylinder head and each end thereof is formed into two divergent ribs 56 and 5i which comprise the other two members of the three-membered ribs. Euch of the divergent rib members 51 is secured to a marginal stud boss and each rib member 56 is secured to a central stud boss Ed. The pillars itl which are reinforced by the three-membered ribs are preferably arranged to underlie the intersection of the rib members 5G, and 5l'. Thus a double Y- shaped strengthening reinforcement is provided for the pillars of the two central combustion faces of the bottom wall 2Q of the cylinder head.

Transverse ribs '58 and 59 are also provided in this design of the cylinder head. The transverse ribs 58 are positioned between central stud bosses and marginal stud boss. These ribs materially increase the rigidity and strength of the upper wall lil of the cylinder head and if desired may cooperate with supplementary posts or pillars 48 which extend through the cooling liquid chamber l2 between the top wall Il) and bottom wall 2E! of the cylinder head and serve to prevent delection of the narrow portions 28 of the bottom wall of the cylinder head which extend between adjacent combustion chambers of the engine. This construction minimizes the likelihood of the narrow portions 28 of the bottom wall 20 becoming suliciently deflected or separated from the vtop of the engine block to permit blow-by to occur between adjacent combustion chambers.

The 'transverse ribs 59 are arranged to strengthen and reinforce the portions of the cylinder head between adjacent cylinders, particularly the narrow portions 29 of the bottom wall 2i) of the cylinder head. Supplementary pillars i9 extend between the top and bottom walls of the cylinder head over the portions 29 of the bottom wall so that the bottom Wall may be reinforced by the transverse ribs 59 'to minimize blow-by between adjacent cylinders of the engine.

In a cylinder head such as that illustrated in Figs. 8 through 13 there will be no objection to a slight obstruction of the flow of cooling liquid through the cooling liquid chamber l2, since in addition to the main cooling liquid outlet 5, auxiliary cooling liquid outlets I6, ll and l are provided. Accordingly, many of the ribs may be formed partially in the cooling liquid chamber as shown in Fig. 13. f made according to this practice, an outer or exposed portion 'ID of the ribs may be formed exteriorly of the top Wall I0 of the cylinder head and the internal portion 'H may underlie the exposed portion 'I0 and be positioned wholly within the cooling liquid chamber l2. In such a construction, of course, the top wall it? of the cylinder head may be'formed integrally with and joined directly into the sides of the ribs, and the pillar or post 40 may similarly be formed into the internal portion 'H of the rib. Even with the use of such a rib, a portion of which is positioned within the cooling liquid chamber, it is to be noted that there is no obstruction to the now of cooling liquid over the bottom wall or compression wall of the cylinder head. Consequently, there is no substantial impairment of the cooling action over the portions of the bottom wall which are in contact with the hot gases inthe combustion chamber.

Cylinder heads constructed in accordance with the present invention exhibit an additional feature which renders their cooling action more efiicient and desirable for use with internal combustion engines. This feature relates to the heat radiating eiect of the ribsl themselves which is particularly noticeable in such cylinder heads constructed ormetals having the property of rapid heat conduction such as copper and aluminum and their alloys. area exposed to the rapidly moving air blown over the exterior surface of the cylinder head by the fan of the cooling system of the engine has an appreciably increased heat dissipating property which tends to improve the operation of the engine and reduce the load on the liquid cooling system.

The lpresent invention thus provides an improved and novel method for strengthening and reinforcing both the upper and lower walls of the cylinder head for an internal combustion engine. This reinforcement involves only a minimum interference with the flow of cooling liquid through the cylinder head and enables the cylinder head to be constructed of an appreciably less amount of material so that substantial economies may be realized in its manufacture and which also increases its efficiency of performance.

The additional surface f:

t is to be understood, however, that the cylinder head designs illustrated in the drawings and described above are given for purposes of explanation only and it is contemplated that numerous modifications-thereof with alterations in the shape and position of the'ribs and pillars are contemplated and intended to be included within the scope of the appended claims.

What I claim is:

1. An internal combustion engine cylinder head having a compression wall to overlie an 'engine combustion chamber', an outer wall spaced from the compression wall to provide a cooling liquid chamber between the walls, a pluralityv of stud bosses for receiving hold-down bolts to secure the head to an engine-block, and reinforcing ribs extending between` the bosses to strengthen the head, said ribs connected to the stud bosseswithin the cooling liquid chamber and having a central portion formed on the exterior` of the outer wall whereby the rib presents a minimum resistance to the iiow of cooling liquid.

2. A cylinder head for an internal combustion engine comprising a compression Wall to overlie a combustion chamber of an engine, an outer wall spaced from the compression wall to provide a cooling liquid chamber between the walls, a plurality of stud bosses connected to both walls and having apertures extending therethrough for receiving hold-down bolts to secure the head to an engine block, at least one of said stud bosses extending through the cooling liquid chamber between the walls and having a central part substantially completely surrounded by the cooling liquid chamber, a projecting rib integrally formed on the outer wall to reinforce the latter, the major part of said rib being disposed outside of the cooling liquid chamber and one end of said rib extending into the cooling liquid chamber in the region of said last mentioned stud boss and secured to the central part of said stud boss. v

3. A cylinder head for an internal combustion engine comprising a compression wall to overlie a combustion chamber of an engine, an outer wall spaced from the compression wall to provide av cooling liquid chamber between the walls,

a projecting rib integrally formed on the outer wall to reinforce the same, the major part of said rib being disposed outside of the cooling liquid chamber, and a post extending through the cooling liquid chamber between said walls, said post having one end secured to the compression wall at a portion of the latter which normally overlies a combustion chamber of an engine, and the other end of said post secured to the outer wall at a region of the latter adjacent a central portion of said rib.

4. A cylinder head for an internal combustion engine comprising a compression wall to be secured to the block of an internal combustion engine and having portions for overlying the combustion chambers of an engine, an outer wall spaced from the compressionwall to provide a cooling liquid chamber between the walls, a plurality of inlet openings formed in the compression wall to admit cooling liquid to the chamber, an outlet through which cooling liquid is withdrawn from thev chamber, said outletbeing remote from the inlets to provide a flow of cooling liquid through the chamber in directions substantially paralleling the walls thereof, and integral ribs` formed on the outer wall and projecting therefrom to reinforce the same, the major part of each of said ribs being disposed wholly outsideV of the cooling liquidchamber to avoid obstructing the flow through the chamber, said inlets and outlet being disposed so that the ow of cooling liquid through the chamber is largely transverse to the length of the ribs.

5. A cylinder head for an internal combustion engine comprising an integral casting having a compression wall to be disposedagainst a block of an engine with portions thereof overlying coml bustion chambers of the engine, an outer wall spaced from the compression wall to yprovide a cooling liquid chamber between the walls, a plurality of 'stud bosses having apertures therethrough for receiving hold-down bolts to secure the head to an engine block, a plurality of integral ribs formed on the outer wall, said ribs having their ends secured to some of said stud bosses, and integral posts extending between the outer wall and compression wall, one end of each of said posts being formedj into one of the compression wall portions which 'overlies avcombustion chamber, and the opposite end of each of said posts being formed into the outer wall adjacent a central part of one of said ribs, whereby deflection of the compression wall both toward and away from the outer wall is resisted by the posts and ribs.

6. An engine cylinder head construction comprising a compression wall to overlie an engine combustion chamber, an outer wall spaced from the compression wall to provide a cooling liquid chamber between the'walls, a pair of ribs integrally formed on the outer wall and projecting outwardly therefrom, said ribs being crossed and the major portions of the ribs being disposed outside of the cooling liquid chamber, and a post extending through said chamber between said walls, said post having one end secured to the compression wall at a portion of the latter which normally overlies an engine combustion chamber, and the other end of said post secured to the outer wall at a region of the latter adjacent the crossing of the ribs.

7. An engine cylinder head construction comprising a compression wall to overlie an engine combustion chamber, an outer wall spaced from the compression wall to provide a cooling liquid chamber between the walls, spaced bosses integral with the outer wall for supporting the same and securing the head to an engine block, a rib integrally formed on the outer wall and projecting outwardly therefrom, said rib extending between spaced bosses and having each of its ends connected to a boss over a distancegreater than the thickness of the outer wall, and a post extending through the cooling liquid chamber between said walls, said post having one end secured to the compression wall and the other end secured to the outer wall at a region of the latter adjacent a central portion of said rib.

8. An engine cylinder head construction comprising a compression wall to overlie an engine combustion chamber, an outer wall spaced from the compression wall to provide a cooling liquid chamber between the walls, an attaching boss integral with the outer wall for supporting the same and securing the head to an engine block, a rib integrally formed on the outer wall and projecting outwardly therefrom sufliciently so that the major part thereof is disposed outside of the cooling liquid chamber, said rib extending laterally from said boss and having one end connected tothe boss over a distance greater than the thickness of the outer wall, and a post extending through the cooling liquid chamber between said walls, said post having one end secured to the compression wall and the other end secured to the outer wall at a region of the latter adjacent said rib whereby the rib and post cooperatively resist deflection of the compression wall and transmit to the boss forces applied to the compression wall by the burning of fuel in the combustion chamber of the engine.

9. An engine cylinder head construction comprising a compression wall to overlie an engine combustion chamber, an outer wall centrally spaced from the compression wall and marginal- 1y connected thereto to provide a cooling liquid chamber between the walls, spaced bosses integral with the outer wall for supporting the same and securing the head to an engine block, and a rib integrally formed on the outside of the central part of the outer wall and projecting outwardly therefrom so that the major portion of the rib is disposed wholly outside of the cooling liquid chamber and is exposed to the atmosphere, said rib extending between a pair of said spaced bosses and having each of its ends connected to a boss over a distance greater than the thickness of the outer wall.

10. An engine cylinder head construction comprising a compression Wall to overlie an engine combustion chamber, an outer wall centrally spaced from the compression wall and marginal- 1y connected thereto to provide a cooling liquid chamber between the walls, spaced bosses integral with the outer wall for supporting the same and securing the head to an engine block, and a pair of ribs integrally formed on the outside of the central part of the outer wall and projecting outwardly therefrom so that the major portion of each rib is disposed wholly outside of the cool- Y ing liquid chamber and is exposed to the atmosphere, said ribs being crossed and each extending between a pair of said spaced bosses, each end of the crossed ribs being connected to a boss over a distance greater than the thickness of the outer Wall.

EVERE'IT G. FAHLMAN.

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