CA1114258A - Liquid-cooled internal combustion engine - Google Patents
Liquid-cooled internal combustion engineInfo
- Publication number
- CA1114258A CA1114258A CA329,687A CA329687A CA1114258A CA 1114258 A CA1114258 A CA 1114258A CA 329687 A CA329687 A CA 329687A CA 1114258 A CA1114258 A CA 1114258A
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- Canada
- Prior art keywords
- cylinder
- cylinder head
- sealing member
- shells
- internal combustion
- Prior art date
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Abstract
? UID-COOLED INTERNAL COMBUSTION ENGINE
ABSTRACT OF THE DISCLOSURE
A liquid-cooled internal combustion engine including a cyl-inder, a cylinder head, a combustion chamber, a cooling liquid chamber disposed around the combustion chamber and a selaing de-vice interposed between the cylinder and the cylinder head to provide a seal therebetween. The sealing device includes an elas-tic sealing member arranged between ends of outer shells of the cylinder and the cylinder head, and a metallic sealing member ar-ranged between ends of inner shells of the cylinder and the cyl-inder head.
ABSTRACT OF THE DISCLOSURE
A liquid-cooled internal combustion engine including a cyl-inder, a cylinder head, a combustion chamber, a cooling liquid chamber disposed around the combustion chamber and a selaing de-vice interposed between the cylinder and the cylinder head to provide a seal therebetween. The sealing device includes an elas-tic sealing member arranged between ends of outer shells of the cylinder and the cylinder head, and a metallic sealing member ar-ranged between ends of inner shells of the cylinder and the cyl-inder head.
Description
Bl .;GROUND OF T~IE INVENTION
This invention relates to liquid-cooled internal combustion engines, and more particularly to a sealing device of a liquid-cooled internal combustion engine interposed between the cylinder and the cylinder head for providing a seal therebetween.
In a liquid-cooled internal combustion engine~ a cylinder and a cylinder head each have an inner shell and an outer shell, and a cooling liquid chamber is defined by the outer shells and inner shells and a combustion chamber is defined by the inner shells, when the cylinder head is connected to the cylinder. In this type of internal combustion engine, i-t is necessary to provide a seal between the cylinder head and the cylinder to prevent leak of gas from the combustion chamber and leak of cooling liquid from the cooling liquid chamber. To this end, a sealing device is provided to prevent leak of gas and cooling liquid. Some disad-vantages are associated with sealing devices of the prior art.
Difficulties are experienced in positively preventing leak of gas from the combustion chamber, and the cylinder and the cylinder head are high in cost due either to high expenses for fabricating a seal-ing device itseIf or to an increase in the production cost of the cylinder and the cylinder head caused by the provision of a seal-ing device. Sealing devices of a certain type even have the det-rimen~al effect of interfering with normal combustion of fuel-air mixtures in the combustion chamber of an internal combustion engine.
SUMMARY OF THE INVENTION
This invention has as its object the provision of a liquid-cooled internal combustion engine provided with a sealing device which obviates the aforesaid disadvantages of the prior art.
The outstancling characteristic of the present invention resides in the provision, in a liquid-cooled internal combustion engine comprising a cylinder and a cylinder head each having an inner shell and an outer shell, the outer shells and -the inner shells of the cylinder and the cylinder head defining a cooling liquid chamber and the inner shells of the cylinder and the cyl-inder and the cylinder head defining a combustion chamber when the cylinder head is connected at its ]ower end to the cylinder at its upper end, of an elastic sealing member held in a gap formed be-tween the upper end of the outer shel:L of the cylinder and the lower end of the outer shell of the cylinder head, and a metallic sealing member held between the upper end of the inner shell of the cylinder and the lower end of the inner shell of the cylinder head.
Additional and other objects~ features and advantages of the present invention will become apparent from the description set forth hereinafter when considered in conjunction with the accom-panying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a sectional view of essential portions of a liquid-cooled internal combustion engine equipped with a sealing device of the prior art;
Fig. 2 is a fragmentary sectional view, on an enlarged scale, of the gasket shown in Fig. l;
Fig. 3 is a sectional view of essential portions of anather liquid-cooled internal combustion engine equipped with a sealing device of the prior art; and Figs. 4 to 6 are sectional views of essential portions of internal combustion engines each having a sealing device according
This invention relates to liquid-cooled internal combustion engines, and more particularly to a sealing device of a liquid-cooled internal combustion engine interposed between the cylinder and the cylinder head for providing a seal therebetween.
In a liquid-cooled internal combustion engine~ a cylinder and a cylinder head each have an inner shell and an outer shell, and a cooling liquid chamber is defined by the outer shells and inner shells and a combustion chamber is defined by the inner shells, when the cylinder head is connected to the cylinder. In this type of internal combustion engine, i-t is necessary to provide a seal between the cylinder head and the cylinder to prevent leak of gas from the combustion chamber and leak of cooling liquid from the cooling liquid chamber. To this end, a sealing device is provided to prevent leak of gas and cooling liquid. Some disad-vantages are associated with sealing devices of the prior art.
Difficulties are experienced in positively preventing leak of gas from the combustion chamber, and the cylinder and the cylinder head are high in cost due either to high expenses for fabricating a seal-ing device itseIf or to an increase in the production cost of the cylinder and the cylinder head caused by the provision of a seal-ing device. Sealing devices of a certain type even have the det-rimen~al effect of interfering with normal combustion of fuel-air mixtures in the combustion chamber of an internal combustion engine.
SUMMARY OF THE INVENTION
This invention has as its object the provision of a liquid-cooled internal combustion engine provided with a sealing device which obviates the aforesaid disadvantages of the prior art.
The outstancling characteristic of the present invention resides in the provision, in a liquid-cooled internal combustion engine comprising a cylinder and a cylinder head each having an inner shell and an outer shell, the outer shells and -the inner shells of the cylinder and the cylinder head defining a cooling liquid chamber and the inner shells of the cylinder and the cyl-inder and the cylinder head defining a combustion chamber when the cylinder head is connected at its ]ower end to the cylinder at its upper end, of an elastic sealing member held in a gap formed be-tween the upper end of the outer shel:L of the cylinder and the lower end of the outer shell of the cylinder head, and a metallic sealing member held between the upper end of the inner shell of the cylinder and the lower end of the inner shell of the cylinder head.
Additional and other objects~ features and advantages of the present invention will become apparent from the description set forth hereinafter when considered in conjunction with the accom-panying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a sectional view of essential portions of a liquid-cooled internal combustion engine equipped with a sealing device of the prior art;
Fig. 2 is a fragmentary sectional view, on an enlarged scale, of the gasket shown in Fig. l;
Fig. 3 is a sectional view of essential portions of anather liquid-cooled internal combustion engine equipped with a sealing device of the prior art; and Figs. 4 to 6 are sectional views of essential portions of internal combustion engines each having a sealing device according
- 2 -.~
to the present invention.
DETAIL~D DESCRIPTION OF THE PREFERRED EMBODIMENTS
To enable the present invention to be better unders-tood~
liquid-cooled in-ternal combustion engines having seal,ing devices of the prior art will be described by referring to Flgs. 1 to 3, prior to the description of embodiment,s of the present invention.
Fig. 1 shows a liquid-cooled internal combustion engine com-prising a cylinder 1 and a cylinder head 6, the cylinder having an inner shell 3 and an outer shell 5 and the cylinder head 6 hav-ing an inner shell 8 and an outer shell 10. The cylinder head 6 is connected at its lower end to the cylinder 1 at its upper end, and a sealing device comprising gaskets 14 is interposed there-between. The inner shells 3 and 8 of the cylinder 1 and cylinder head 6 respectively define a combustion chamber 2, a portion of the combustion chamber defined by the inner shell 8 of the cylinder head 6 constituting an upper combustion chamber 7. The inner shells 3 and 8 of the cylinder 1 and cylinder head 6 and the outer shells 5 and 10 thereof define cooling liquid chamber portions 4 and 9 respectively which communicate with each other to constitute a cooling liquid chamber.
As shown in Fig. 2 each gasket 14 comprises an annular asbes-tos plate 12 having core bars 11 embedded therein and a grommet 13 of stainless steel attached to each of inner and outer peripheral edges thereof. The gaskets 14 of the aforesaid construction are interposed between ends of ~he cylinder 1 and cylinder head 6 which are fastened together by bolts 15. In this way, the gaskets 14 provide seals to end surf.aces of the cylinder 1 and cylinder head S.
Fig. 3 shows another liquid-cooled internal combustlon engine slmilar to the liquid-cooled :internal combustion engine shown in Fig. 1 comprising a cylinder 1 having inner and outer shells 3 and 5, a cylinder head 6 having inner and outer shells 8 and 10, a combustion chamber 2, an upper combustion chamber 7, a cooling liquid chamber including cooling liquid chamber portions 4 and 9, and bolts 15. The internal combustion cylinder shown in Fig. 3 is distinct from the internal combustion cylinder shown in Fig. 1 in that an annular groove 16 is formecl at the upper end of the inner shell 3 and outer shell 5 oE the cylinder 1 to receive therein an O-ring 17 formed of heat resistant rubber. The O-r:ings 17 are held between ends of -the cylinder 1 and cylinder head 6 by the clamping force of the bolts 15 to serve as a sealing device for providing seal to end surfaces of the cylinder 1 and cylinder head 6.
Typical examples of the sealing device of a liquid-cooled internal combustion engine have been described hereinabove. In the sealing device shown in Fig. 1, excessively large pressure would be applied to the gaskets 14 as a result of thermal expan-sion of the internal shells 3 and 8 and the outer shells 5 and 10 which would occur as the internal combustion engine operates.
This would cause permanent deformation of the gaskets 14 which might results in the bol-ts 15 failing in fastening the cylinder 1 and cylinder head 6 together. Also, earh gasket 14 is in contact with the ends of the cylinder 1 and cylinder head 6 in a large area and consequently the pressure acting on each gasket 14 per unit area is low. The result of this would be that each gasket 14 might not perform a satisfactory sealing action, causing leak of gas from the combustion chamber 2. Since each gasket 14 is pressed by the clamping force exerted by the bolts 15, the grommets 13 at the inner and outer peripheral edges of the asbestos plates 12 would also be pressed downwardly and migh-t be dislodged from their positons. The asbestos pla-te 12 forming each gasket 14 has a low thermal conductivity, and this might cause the heat of com-bustion of fuel-air mixtures to be retained by the stainless steel grommet 13 at the inner peripheral edge of the gasket 14 of the inner shells 3 and 8. The grommet 13 thus overheated might cause ignition of fuel~air mixtures in the combustion chamber 2 by the heat of the superheated grommet 13, thereby resulting in abnormal combustion of fuel-air mixtures in the internal combustion engine.
The gasket 14 interposed between -the inner shells 3 and 8 of the cylinder 1 and cylinder head 6 respectively must be treated with a special liquid by dipping techniques, in order to prevent leak of cooling liquid from the cooling liquid chamber and to prevent seeping of liquid through openings 14a for the bolts 15 to extend therethrough. Thus the sealing device shown in Fig. 1 would be high in cost.
In the liquid-cooled internal combustion engine shown in Fig.
to the present invention.
DETAIL~D DESCRIPTION OF THE PREFERRED EMBODIMENTS
To enable the present invention to be better unders-tood~
liquid-cooled in-ternal combustion engines having seal,ing devices of the prior art will be described by referring to Flgs. 1 to 3, prior to the description of embodiment,s of the present invention.
Fig. 1 shows a liquid-cooled internal combustion engine com-prising a cylinder 1 and a cylinder head 6, the cylinder having an inner shell 3 and an outer shell 5 and the cylinder head 6 hav-ing an inner shell 8 and an outer shell 10. The cylinder head 6 is connected at its lower end to the cylinder 1 at its upper end, and a sealing device comprising gaskets 14 is interposed there-between. The inner shells 3 and 8 of the cylinder 1 and cylinder head 6 respectively define a combustion chamber 2, a portion of the combustion chamber defined by the inner shell 8 of the cylinder head 6 constituting an upper combustion chamber 7. The inner shells 3 and 8 of the cylinder 1 and cylinder head 6 and the outer shells 5 and 10 thereof define cooling liquid chamber portions 4 and 9 respectively which communicate with each other to constitute a cooling liquid chamber.
As shown in Fig. 2 each gasket 14 comprises an annular asbes-tos plate 12 having core bars 11 embedded therein and a grommet 13 of stainless steel attached to each of inner and outer peripheral edges thereof. The gaskets 14 of the aforesaid construction are interposed between ends of ~he cylinder 1 and cylinder head 6 which are fastened together by bolts 15. In this way, the gaskets 14 provide seals to end surf.aces of the cylinder 1 and cylinder head S.
Fig. 3 shows another liquid-cooled internal combustlon engine slmilar to the liquid-cooled :internal combustion engine shown in Fig. 1 comprising a cylinder 1 having inner and outer shells 3 and 5, a cylinder head 6 having inner and outer shells 8 and 10, a combustion chamber 2, an upper combustion chamber 7, a cooling liquid chamber including cooling liquid chamber portions 4 and 9, and bolts 15. The internal combustion cylinder shown in Fig. 3 is distinct from the internal combustion cylinder shown in Fig. 1 in that an annular groove 16 is formecl at the upper end of the inner shell 3 and outer shell 5 oE the cylinder 1 to receive therein an O-ring 17 formed of heat resistant rubber. The O-r:ings 17 are held between ends of -the cylinder 1 and cylinder head 6 by the clamping force of the bolts 15 to serve as a sealing device for providing seal to end surfaces of the cylinder 1 and cylinder head 6.
Typical examples of the sealing device of a liquid-cooled internal combustion engine have been described hereinabove. In the sealing device shown in Fig. 1, excessively large pressure would be applied to the gaskets 14 as a result of thermal expan-sion of the internal shells 3 and 8 and the outer shells 5 and 10 which would occur as the internal combustion engine operates.
This would cause permanent deformation of the gaskets 14 which might results in the bol-ts 15 failing in fastening the cylinder 1 and cylinder head 6 together. Also, earh gasket 14 is in contact with the ends of the cylinder 1 and cylinder head 6 in a large area and consequently the pressure acting on each gasket 14 per unit area is low. The result of this would be that each gasket 14 might not perform a satisfactory sealing action, causing leak of gas from the combustion chamber 2. Since each gasket 14 is pressed by the clamping force exerted by the bolts 15, the grommets 13 at the inner and outer peripheral edges of the asbestos plates 12 would also be pressed downwardly and migh-t be dislodged from their positons. The asbestos pla-te 12 forming each gasket 14 has a low thermal conductivity, and this might cause the heat of com-bustion of fuel-air mixtures to be retained by the stainless steel grommet 13 at the inner peripheral edge of the gasket 14 of the inner shells 3 and 8. The grommet 13 thus overheated might cause ignition of fuel~air mixtures in the combustion chamber 2 by the heat of the superheated grommet 13, thereby resulting in abnormal combustion of fuel-air mixtures in the internal combustion engine.
The gasket 14 interposed between -the inner shells 3 and 8 of the cylinder 1 and cylinder head 6 respectively must be treated with a special liquid by dipping techniques, in order to prevent leak of cooling liquid from the cooling liquid chamber and to prevent seeping of liquid through openings 14a for the bolts 15 to extend therethrough. Thus the sealing device shown in Fig. 1 would be high in cost.
In the liquid-cooled internal combustion engine shown in Fig.
3, it is necessary to impart high precision finishes to the sur-faces of the upper ends of inner and outer shells 3 and 5 and the lower ends of inner and outer shells 8 and 10, in order to bring them into intimate contact with one another. The outer shells 5 and 10 are generally complex in shape and consequently difficulties are experienced in work1ng on them to form the groove 16. The provision of the groove 16 on the upper end surface of the outer shells 5 (the groove 16 may be formed in the outer shell 10 instead of the outer shell 5 as shown) makes it necessary to increase the thickness of the outer shells 5 and 10 or to form flanges 5a and lOa at the opposed surfaces of the outer shells 5 and 10 as shown.
The formation of the flanges 5a and lOa would reduce efficiency producing the cylinder 1 and cylinder head 6 because cores are required to produce them by casting.
A fatal disadvantage common to the sealing devices shown in .
.~
Figs. 1 and 3 will now be described. Generally, in this type o~
liquid-cooled internal combustion engine~ the combustion chamber 2 is higher in pressure than other portions. Thus, in order -to positively prevent leak of gas ~rom the combustion cylinder 2, it is necessary to provide a good airtight seal between th~ inner shells 3 and 8 o~ the cylinder 1 and cylinder head 6 respectively by applying high pressure to the sealing member located there-between. Meanwhile the pressure in the cooling chamber 4, 9 is not so high as the pressure in the combus-tion chamber 2, so that relatively low pressure may be applied to the sealing member lo-cated between the outer shells S and 10 of the cylinder 1 and cyl-inder head 6 respectively. As can be seen in Figs. 1 and 3, sub-stantially equal pressure per unit area is applied by the bolts 15 to -the sealing members between the outer shells 5 and 10 and the inner shells 3 and 8 in liquid-cooled internal combustion engines of the prior art. Thus a situation would be created where-in the pressure applied to the sealing member between the inner shells 3 and 8 is not high enough to provide an adequate seal in spite of the fact that the pressure applied to the séaling member between the outer shells 5 and 10 is higher than is necessary.
T-hus there arises the need to apply an exceedingly high clamping force as by increasing the number of bolts 15~ in order to apply sufficiently high pressure to the sealing member between the inner shells 3 and 8 to prevent leak of gas therethrough.
Figs. 4 to 6 show some embodiments of the present invention.
In these figures, parts similar to those shown in Figs. 1 to 3 are designated by like reference characters in all the drawings. That is, in the liquid-cooled internal combustion engines shown in Figs.
The formation of the flanges 5a and lOa would reduce efficiency producing the cylinder 1 and cylinder head 6 because cores are required to produce them by casting.
A fatal disadvantage common to the sealing devices shown in .
.~
Figs. 1 and 3 will now be described. Generally, in this type o~
liquid-cooled internal combustion engine~ the combustion chamber 2 is higher in pressure than other portions. Thus, in order -to positively prevent leak of gas ~rom the combustion cylinder 2, it is necessary to provide a good airtight seal between th~ inner shells 3 and 8 o~ the cylinder 1 and cylinder head 6 respectively by applying high pressure to the sealing member located there-between. Meanwhile the pressure in the cooling chamber 4, 9 is not so high as the pressure in the combus-tion chamber 2, so that relatively low pressure may be applied to the sealing member lo-cated between the outer shells S and 10 of the cylinder 1 and cyl-inder head 6 respectively. As can be seen in Figs. 1 and 3, sub-stantially equal pressure per unit area is applied by the bolts 15 to -the sealing members between the outer shells 5 and 10 and the inner shells 3 and 8 in liquid-cooled internal combustion engines of the prior art. Thus a situation would be created where-in the pressure applied to the sealing member between the inner shells 3 and 8 is not high enough to provide an adequate seal in spite of the fact that the pressure applied to the séaling member between the outer shells 5 and 10 is higher than is necessary.
T-hus there arises the need to apply an exceedingly high clamping force as by increasing the number of bolts 15~ in order to apply sufficiently high pressure to the sealing member between the inner shells 3 and 8 to prevent leak of gas therethrough.
Figs. 4 to 6 show some embodiments of the present invention.
In these figures, parts similar to those shown in Figs. 1 to 3 are designated by like reference characters in all the drawings. That is, in the liquid-cooled internal combustion engines shown in Figs.
4 to 6, there are provided a cylinder 1 having inner and outer shells 3 and 5, a cylinder head 6 having inner and outer shells 8 and 10, a combustion chamber 2 and an upper combustion chamber 7 de~ined by the inner shell6 3 and 8~ bolts 15 for fastening the cylinder 1 and cylinder head 6 toge-ther by -their cl~mping forces, and cooling liquid chamber ~ 9 defined by the outer shells 5, 10 and inner shells 3, 8, which are similar to those shown in Figs. 1 and 3. Therefore, detailed descrip-tion of these parts will be omitted.
Fig. 4 shows a first embodiment in which an annular offset portion 20 is formed at the inner peripheral sec-tion of the upper end surface of the inner shell 3 o-f the cylinder 1 for receiving therein a metallic sealing member 21 of a thickness greater than the depth of the offset portion 20. The sealing member 21 is preferably formed of a metal high in thermal resistance~ compres-sive strength and thermal conductivity (or offering least resist-ance to the conduction of heat). Although there are many metals which satisfy these requirements, the metallic seal member 21 will be formed advantageously of copper because this metal makes it possible to reduce production cost.
The upper end of the outer shell 5 of cylinder 1 is lower in height than the upper end of the inner shell 3 thereof to form a gap 22 between the upper end of the outer shell 5 of cylinder 1 and the lower end of the outer shell 10 of cylinder head 6. An elastic sealing member 23 formed of rubber or other resilient material is fitted in the gap 22 between the ends of the outer shells 5 and 10 of cylinder 1 and cylinder head 6 respectiYely.
The cylinder 1 and cylinder head 6 are fastened together by bolts 15. By clamping the cylinder head 6 to the cylinder 1 in this way, the upper end of the inner shell 3 of the cylinder 1 is connected to the lower end of the inner shell 8 of the cyli.nder head 6 through the metallic sealing member 21 and opposed surfaces of the ends are sealed by the metallic sealing member 21 inter-posed therebetween. At the same time, opposed surfaces of the -- 7 -- ..
-~per end of the outer shell 5 o-f cylinder 1 and the lower end of the outer shell 10 of cylinder head 6 are sealed by the elastic sealing member 23 interposed therebetween and compressed by -the outer shells.
Fig. 5 shows a second embodiment, in which annular metallic sealing member 21' formed of copper, Eor example, like the metallic sealing member 21 of the embodiment shown in Fig. 4 is interposed between the upper end of the inner shell 3 of cylinder 1 and the lower end of the inner shell 8 of cylinder head. The upper end of the outer shell 5 of cylinder 1 is lower in height than the upper end of the inner shell 3 thereof to form a gap 22 between the upper end of the outer shell S of cylinder 1 and the lower end of the outer shell 10 of cylinder head 6? and an elastic sealing member 24 formed of rubber or the like is fitted in the gap 22 and interposed between opposed surfaces of the ends of outer shells 5 and 10. In this embodiment, the elastic sealing member 24 is sub-stantially in the form of~an inverted U in cross section. The cylinder 1 and cylinder head 6 are fastened together by bolts 15.
By clamping the cylinder head 6 to the cylinder 1 in this way, the upper end of the inner shell 3 of cylinder 1 is connected to the lower end of the inner shell 8 of cylinder head 6 through the metallic sealing member 21' and opposed surfaces of the ends are sealed by the metallic sealing member 21l, and opposed surfaces of the upper end of the outer ~hell 5 of cylinder 1 and the lower end of the outer shell 10 of cylinder head 6 are sealed by the elastic sealing member 24 interposed therebetween and compressed by the outer shells. `
Fig. 6 showsa third embodiment, in which an annular groove 16 is formed on the upper end of the inner shell 3 of cylinder 1 and extends along the surface thereof for receiving therein a metallic sealing member 25 which is a metallic O-ring having a 2~ ~
-thlckness greater than the depth of the groove 16. Meanwhile the upper end of the outer shell 5 of cylinder 1 is lower in height than the upper end of the inner shell 3 thereo- to form a gap 22 between the upper end of the outer shell 5 and the lower end of the outer shell 10 of cylinder head 6, and an elastic sealing member 27 formed of rubber or the like is fitted in the gap 22 and interspoed between the surfaces of the ends of outer shells 5 and 10. In this embodiment too, the elas-t:ic sealing member 27 is in the form of an inverted U in cross section and has -two ribs 26 formed on its upper surface. The cylinder 1 and cylinder head 6 are fas-tened together by bolts 15. By clamping the cylinder head 6 to cylinder 1 in this way, -the upper end of the inner shell 3 of cylinder 1 is connected to the lower end of the inner shell 8 of cylinder head 6 through the metallic sealing member 25 and op-posed surfaces of the ends are sealed by the metallic sealing member 25, and opposed surfaces of the upper end of the outer shell 5 of cylinder 1 and the lower end of the outer shell 10 of cylinder head 6 are sealed by the elastic sealing member 27 com-pressed and interposed therebetween. The metallic sealing member 25 of this embodiment performs the same function as the metallic sealing members 21 and 21l of the aforesaid embodiments. There-fore, the metallic sealing member 25 is also preferably formed of copper or other metal which is high in thermal resistance, thermal conductivity and compressive strength.
The annular offset portion 20 shown in Fig. 4 for receiving the metallic sealing member 21 therein and the annular groove 16 shown in Fig. 6 for receiving the metallic 0-ring 25 therein may be formed on the lower end of the inner shell 8 of cylinder head 6. In the embodiments shown and described hereinabove, the gap 22 between the upper end of the ou-ter shell 5 of cylinder 1 and the lower Fnd of the outer she11 10 of oylinder head 6 is formed , ~ `reducing the he:ight o-f the upper end of the outer shell 5 of cylinder 1 to a level lower than the heigh-t of the upper end oP
the inner shell 3 thereof. However, the gap 22 may be formed by raising the lower end of the outer shell 10 of cylinder head 6 to a level higher than the lower end of the inner shell 8 thereof.
Also, when the metallic sealing member between -the upper end of the inner shell 3 of cylinder 1 and the lower end o-f the inner shell 8 of cylinder head 6 has a large thickness, the large gap is provided between the upper end of the outer shell 5 of cylinder 1 and the lower end of the outer shell 10 of the cylinder head 6 by the thickness of the metallic sealing member. Therefore, the elastic sealing member may be held in the gap provided by the thickness of the metallic sealing member. The elas-tic sealing members 24 and 27 shown in Figs. 5 and 6 respectively may be each fitted in the gap 22 by placing same upside down. The metallic sealing members 21 and 211 shown in Figs. 4 and 5 respectively may be formed of suitable material other than copper, such as an annular aluminum plate, when the metallic sealing members are each held between the upper end of the inner shell 3 of cylinder 1 and the lower end of the inner shell 8 of cylinder head 6 as described hereinabove.
The metallic O-ring of the metallic sealing member 25 shown in Fig. 6 may also be formed of a suitable material other than copper which has high thermal resistance.
As described hereinabove, the sealing device of a liquid-cooled internal combustion engine comprises a metallic sealing member in-terposed between the inner shells of the cylinder and cylinder head, and an elastic sealing~ member interposed between the outer shells thereof. By this structural feature, the disadvantages of the prior art can be eliminated. First, the surface pressure of op-posed surfaces of the upper end of the inner shell of the cylinder - 10 _ an~ the lower end of the inner shell of the cylinder head can be increased, and the sealing member in-terposed between opposed sur-faces has high strength because it is formed of metal. Thus per-manent deformation of the sealing member by thermal expansion of the inner shells o the cylinder and cylinder head can be reduced, thereby minimi~ing leak of gas from the combustion chamber.
Secondly, the metallic sealing member interposed between the upper end of the inner shell of the cylinder and the lower end of the inner shell of the cylinder head has higher thermal conductiv-ity than the gasket of the prior art or ofers least resistance to the conduction of heat, so that abnormal combustion of fuel~
air mixtures taking place in the vicinity of the grommet of stain-less steel disposed at the inner peripheral edge of the gasket of the prior art can be avoided.
Thirdly, the provision of an elastic sealing member inter-posed between and compressed by the upper end of the outer shell of the cylinder and the lower end of the ou-ter shell of the cyl-inder head for sealing opposed surfaces of the ends eliminates the need to increase the thickness of the outer shells of the cyl-inder and cylinder head or to form a flange at the abutting ends of the cylinder and cylinder head, as is done in the prior art in which the outer shells are sealed by an O-ring. Thus there is no need to use cores in producing the cylinder and cylinder head by casting, thereby enabling the cylinder and cylinder head to be produced economically. Moreover, the surfaces of the upper end of the outer shell of cylinder and the lower end of the outer shell -of cylinder head requires no precision finishes and ordinary fin-ishes are tolerated, a~ter being cast. This is conductive to in-creased productivity.
Fourthly, the provision of a gap between the upper end of the outer shell of the cylinder and the lower end of the outer shell of the cylinder head for receiv:ing therein a sealing member of resilient material and the arranging of a metallic sealing member between the opposing surfaces of the ends of -the inner shells ren-der the sealing member between the opposing surfaces oE the ends of the inner shells less deformable than the sealing member be-tween opposed surfaces o-f the ends of -the outer shells. Thus when the cylinder and cylinder head are fastened to~ether as by bolts, for example, the clamping force exerted by -the bolts mainly acts on the metallic sealing member for the inner shells and no high pressure is applied to the elastic sealing member Eor the outer shells. This makes it possible to use a smaller clamping force than has hitherto been considered necessary in a liquid-cooled internal combustion engine of the prior art, to apply high pres-sure to the metallic sealing member for the inner shells for pos-itively sealing the combustion chamber.
Generally when an internal combustion engine operates, marked temperature differential is produced between the portion of the cylinder head near the combustion chamber and the outer peripheral portion of the cylinder head, thereby causing thermal deformation of the cylinder head. In this case, the portion of the cylinder head near the combustion head is usually solid in construction and bolts or other clamping means is located in the portion of the cylinder head near the combustion chamber. As a result, the por-tion of the cylinder head near the combustion chamber undergoes little thermal deformation while thermal deformation tends to take place on a large scale in the outer peripheral portion there-of. Even this phenomenon occurs, the present invention can cope with the situation. That is, since an elastic sealing member is located in the gap hetween opposed surfaces of the outer shells of the cylinder and cylinder head, the thermal deformation that would occur in the outer peripheral portion of cylinder head is ab6crbed by the ela,stic ,sealing member, thereby enabling -the sealing device -to act in a ,stable manner.
~, , ;~ ` ' ., .
.
- 13 _
Fig. 4 shows a first embodiment in which an annular offset portion 20 is formed at the inner peripheral sec-tion of the upper end surface of the inner shell 3 o-f the cylinder 1 for receiving therein a metallic sealing member 21 of a thickness greater than the depth of the offset portion 20. The sealing member 21 is preferably formed of a metal high in thermal resistance~ compres-sive strength and thermal conductivity (or offering least resist-ance to the conduction of heat). Although there are many metals which satisfy these requirements, the metallic seal member 21 will be formed advantageously of copper because this metal makes it possible to reduce production cost.
The upper end of the outer shell 5 of cylinder 1 is lower in height than the upper end of the inner shell 3 thereof to form a gap 22 between the upper end of the outer shell 5 of cylinder 1 and the lower end of the outer shell 10 of cylinder head 6. An elastic sealing member 23 formed of rubber or other resilient material is fitted in the gap 22 between the ends of the outer shells 5 and 10 of cylinder 1 and cylinder head 6 respectiYely.
The cylinder 1 and cylinder head 6 are fastened together by bolts 15. By clamping the cylinder head 6 to the cylinder 1 in this way, the upper end of the inner shell 3 of the cylinder 1 is connected to the lower end of the inner shell 8 of the cyli.nder head 6 through the metallic sealing member 21 and opposed surfaces of the ends are sealed by the metallic sealing member 21 inter-posed therebetween. At the same time, opposed surfaces of the -- 7 -- ..
-~per end of the outer shell 5 o-f cylinder 1 and the lower end of the outer shell 10 of cylinder head 6 are sealed by the elastic sealing member 23 interposed therebetween and compressed by -the outer shells.
Fig. 5 shows a second embodiment, in which annular metallic sealing member 21' formed of copper, Eor example, like the metallic sealing member 21 of the embodiment shown in Fig. 4 is interposed between the upper end of the inner shell 3 of cylinder 1 and the lower end of the inner shell 8 of cylinder head. The upper end of the outer shell 5 of cylinder 1 is lower in height than the upper end of the inner shell 3 thereof to form a gap 22 between the upper end of the outer shell S of cylinder 1 and the lower end of the outer shell 10 of cylinder head 6? and an elastic sealing member 24 formed of rubber or the like is fitted in the gap 22 and interposed between opposed surfaces of the ends of outer shells 5 and 10. In this embodiment, the elastic sealing member 24 is sub-stantially in the form of~an inverted U in cross section. The cylinder 1 and cylinder head 6 are fastened together by bolts 15.
By clamping the cylinder head 6 to the cylinder 1 in this way, the upper end of the inner shell 3 of cylinder 1 is connected to the lower end of the inner shell 8 of cylinder head 6 through the metallic sealing member 21' and opposed surfaces of the ends are sealed by the metallic sealing member 21l, and opposed surfaces of the upper end of the outer ~hell 5 of cylinder 1 and the lower end of the outer shell 10 of cylinder head 6 are sealed by the elastic sealing member 24 interposed therebetween and compressed by the outer shells. `
Fig. 6 showsa third embodiment, in which an annular groove 16 is formed on the upper end of the inner shell 3 of cylinder 1 and extends along the surface thereof for receiving therein a metallic sealing member 25 which is a metallic O-ring having a 2~ ~
-thlckness greater than the depth of the groove 16. Meanwhile the upper end of the outer shell 5 of cylinder 1 is lower in height than the upper end of the inner shell 3 thereo- to form a gap 22 between the upper end of the outer shell 5 and the lower end of the outer shell 10 of cylinder head 6, and an elastic sealing member 27 formed of rubber or the like is fitted in the gap 22 and interspoed between the surfaces of the ends of outer shells 5 and 10. In this embodiment too, the elas-t:ic sealing member 27 is in the form of an inverted U in cross section and has -two ribs 26 formed on its upper surface. The cylinder 1 and cylinder head 6 are fas-tened together by bolts 15. By clamping the cylinder head 6 to cylinder 1 in this way, -the upper end of the inner shell 3 of cylinder 1 is connected to the lower end of the inner shell 8 of cylinder head 6 through the metallic sealing member 25 and op-posed surfaces of the ends are sealed by the metallic sealing member 25, and opposed surfaces of the upper end of the outer shell 5 of cylinder 1 and the lower end of the outer shell 10 of cylinder head 6 are sealed by the elastic sealing member 27 com-pressed and interposed therebetween. The metallic sealing member 25 of this embodiment performs the same function as the metallic sealing members 21 and 21l of the aforesaid embodiments. There-fore, the metallic sealing member 25 is also preferably formed of copper or other metal which is high in thermal resistance, thermal conductivity and compressive strength.
The annular offset portion 20 shown in Fig. 4 for receiving the metallic sealing member 21 therein and the annular groove 16 shown in Fig. 6 for receiving the metallic 0-ring 25 therein may be formed on the lower end of the inner shell 8 of cylinder head 6. In the embodiments shown and described hereinabove, the gap 22 between the upper end of the ou-ter shell 5 of cylinder 1 and the lower Fnd of the outer she11 10 of oylinder head 6 is formed , ~ `reducing the he:ight o-f the upper end of the outer shell 5 of cylinder 1 to a level lower than the heigh-t of the upper end oP
the inner shell 3 thereof. However, the gap 22 may be formed by raising the lower end of the outer shell 10 of cylinder head 6 to a level higher than the lower end of the inner shell 8 thereof.
Also, when the metallic sealing member between -the upper end of the inner shell 3 of cylinder 1 and the lower end o-f the inner shell 8 of cylinder head 6 has a large thickness, the large gap is provided between the upper end of the outer shell 5 of cylinder 1 and the lower end of the outer shell 10 of the cylinder head 6 by the thickness of the metallic sealing member. Therefore, the elastic sealing member may be held in the gap provided by the thickness of the metallic sealing member. The elas-tic sealing members 24 and 27 shown in Figs. 5 and 6 respectively may be each fitted in the gap 22 by placing same upside down. The metallic sealing members 21 and 211 shown in Figs. 4 and 5 respectively may be formed of suitable material other than copper, such as an annular aluminum plate, when the metallic sealing members are each held between the upper end of the inner shell 3 of cylinder 1 and the lower end of the inner shell 8 of cylinder head 6 as described hereinabove.
The metallic O-ring of the metallic sealing member 25 shown in Fig. 6 may also be formed of a suitable material other than copper which has high thermal resistance.
As described hereinabove, the sealing device of a liquid-cooled internal combustion engine comprises a metallic sealing member in-terposed between the inner shells of the cylinder and cylinder head, and an elastic sealing~ member interposed between the outer shells thereof. By this structural feature, the disadvantages of the prior art can be eliminated. First, the surface pressure of op-posed surfaces of the upper end of the inner shell of the cylinder - 10 _ an~ the lower end of the inner shell of the cylinder head can be increased, and the sealing member in-terposed between opposed sur-faces has high strength because it is formed of metal. Thus per-manent deformation of the sealing member by thermal expansion of the inner shells o the cylinder and cylinder head can be reduced, thereby minimi~ing leak of gas from the combustion chamber.
Secondly, the metallic sealing member interposed between the upper end of the inner shell of the cylinder and the lower end of the inner shell of the cylinder head has higher thermal conductiv-ity than the gasket of the prior art or ofers least resistance to the conduction of heat, so that abnormal combustion of fuel~
air mixtures taking place in the vicinity of the grommet of stain-less steel disposed at the inner peripheral edge of the gasket of the prior art can be avoided.
Thirdly, the provision of an elastic sealing member inter-posed between and compressed by the upper end of the outer shell of the cylinder and the lower end of the ou-ter shell of the cyl-inder head for sealing opposed surfaces of the ends eliminates the need to increase the thickness of the outer shells of the cyl-inder and cylinder head or to form a flange at the abutting ends of the cylinder and cylinder head, as is done in the prior art in which the outer shells are sealed by an O-ring. Thus there is no need to use cores in producing the cylinder and cylinder head by casting, thereby enabling the cylinder and cylinder head to be produced economically. Moreover, the surfaces of the upper end of the outer shell of cylinder and the lower end of the outer shell -of cylinder head requires no precision finishes and ordinary fin-ishes are tolerated, a~ter being cast. This is conductive to in-creased productivity.
Fourthly, the provision of a gap between the upper end of the outer shell of the cylinder and the lower end of the outer shell of the cylinder head for receiv:ing therein a sealing member of resilient material and the arranging of a metallic sealing member between the opposing surfaces of the ends of -the inner shells ren-der the sealing member between the opposing surfaces oE the ends of the inner shells less deformable than the sealing member be-tween opposed surfaces o-f the ends of -the outer shells. Thus when the cylinder and cylinder head are fastened to~ether as by bolts, for example, the clamping force exerted by -the bolts mainly acts on the metallic sealing member for the inner shells and no high pressure is applied to the elastic sealing member Eor the outer shells. This makes it possible to use a smaller clamping force than has hitherto been considered necessary in a liquid-cooled internal combustion engine of the prior art, to apply high pres-sure to the metallic sealing member for the inner shells for pos-itively sealing the combustion chamber.
Generally when an internal combustion engine operates, marked temperature differential is produced between the portion of the cylinder head near the combustion chamber and the outer peripheral portion of the cylinder head, thereby causing thermal deformation of the cylinder head. In this case, the portion of the cylinder head near the combustion head is usually solid in construction and bolts or other clamping means is located in the portion of the cylinder head near the combustion chamber. As a result, the por-tion of the cylinder head near the combustion chamber undergoes little thermal deformation while thermal deformation tends to take place on a large scale in the outer peripheral portion there-of. Even this phenomenon occurs, the present invention can cope with the situation. That is, since an elastic sealing member is located in the gap hetween opposed surfaces of the outer shells of the cylinder and cylinder head, the thermal deformation that would occur in the outer peripheral portion of cylinder head is ab6crbed by the ela,stic ,sealing member, thereby enabling -the sealing device -to act in a ,stable manner.
~, , ;~ ` ' ., .
.
- 13 _
Claims
1. A liquid-cooled internal combustion engine comprising:
a cylinder having an inner shell and an outer shell;
a cylinder head having an inner shell and an outer shell;
said cylinder head being connected at its lower end to said cylinder;
a cooling liquid chamber defined by the inner shells and outer shells of the cylinder and the cylinder head; and a combustion chamber defined by the inner shells of the cylin-der and the cylinder head;
wherein the improvement comprises:
an elastic sealing member held in a gap formed between the upper end of the outer shell of the cylinder and the lower end of the outer shell of the cylinder head; and a metallic sealing member held between the upper end of the inner shell of the cylinder and the lower end of the inner shell of the cylinder head.
a cylinder having an inner shell and an outer shell;
a cylinder head having an inner shell and an outer shell;
said cylinder head being connected at its lower end to said cylinder;
a cooling liquid chamber defined by the inner shells and outer shells of the cylinder and the cylinder head; and a combustion chamber defined by the inner shells of the cylin-der and the cylinder head;
wherein the improvement comprises:
an elastic sealing member held in a gap formed between the upper end of the outer shell of the cylinder and the lower end of the outer shell of the cylinder head; and a metallic sealing member held between the upper end of the inner shell of the cylinder and the lower end of the inner shell of the cylinder head.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA329,687A CA1114258A (en) | 1979-06-13 | 1979-06-13 | Liquid-cooled internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA329,687A CA1114258A (en) | 1979-06-13 | 1979-06-13 | Liquid-cooled internal combustion engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1114258A true CA1114258A (en) | 1981-12-15 |
Family
ID=4114441
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA329,687A Expired CA1114258A (en) | 1979-06-13 | 1979-06-13 | Liquid-cooled internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1114258A (en) |
-
1979
- 1979-06-13 CA CA329,687A patent/CA1114258A/en not_active Expired
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| MKEX | Expiry |