US 4,791,891 AGranted

Reciprocating piston engine

AssigneeMAN Nutzfahrzeuge AG

InventorsHeribert Kubis, Josef Winter

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Abstract

A reciprocating piston engine having a sealing system between the cylinder head and the cylinder liner, or the cylinder block, using a metal gasket. It is proposed to improve such a system in a manner that, while large manufacturing tolerances are permitted, i.e. tolerances on the dimensional design of the cooperating parts as well as on the cylinder head bolt torque, reliable gastight sealing of the combustion chamber is ensured at all times. This is essentially achieved in that a circumferential raised portion on the liner flange is the only part that projects beyond the top end (sealing face) of the cylinder block and is matched to the metal gasket in a manner that when the cylinder head is tightened down on the cylinder block, the cylinder head gasket is always stressed above the yield point, with the metal gasket having such a stress/strain characteristic that once the yield point is exceeded, the horizontal deformation range (i.e. where the compressive stress is constant) is as great as possible.

Claims5

Dependent claims

In a reciprocating piston engine having cooperating parts including a cylinder block, at least one cylinder head that can be securely tightened to said cylinder block, and at least one replaceable cylinder liner, whereby in each cylinder liner there is slideably disposed a respective piston and a combustion chamber is provided that is delimited by said cylinder head, said cylinder liner, and said piston, with said cylinder liner being supported on said cylinder block via a liner shoulder, and with that end face of said liner shoulder that faces said cylinder head being provided with a first raised edge portion in that portion of said end face contiguous to said combustion chamber, and also being provided with a radially outwardly open recess, which has a base, in the remaining portion of said liner shoulder end face, with the latter further being provided in said recess region with a circumferential second raised portion that is directed toward said cylinder head, whereby a continuous plate-like cylinder head gasket, made of solid metal, is disposed in said recess between said cylinder head and said cylinder block, the improvement in combination therewith wherein:

only said second raised portion, and not said base of said recess, extends and includes a projection having a penetration depth for a distance, in the direction toward said cylinder head, as well as being located above said base of said recess and via only said projection for a distance of penetration depth relative to as well as beyond an end face of said cylinder block that faces said cylinder head;
and wherein said cylinder head gasket has a defined compressive strength of the gasket with full surface seal support exclusively between said cylinder head and said cylinder block, and said second raised portion is matched with said cylinder head gasket in such a way that when said cylinder head is secured to said cylinder block, said gasket is always stressed beyond the yield point and is positively interlocked with said second raised portion due to plastic deformation at a quantitatively regulated pressure force dependent exclusively upon flow limit of the gasket in a region of said projection whereas gasket regions to the left and right thereof have no engagement with the cylinder liner, with said penetration of said second raised portion into said cylinder head gasket being completed as soon as a remaining portion of said gasket comes into contact with said end face of said cylinder block, and with said cylinder head gasket having such a stress/strain characteristic that once said yield point is exceeded, a maximum, substantially constant compressive strength deformation range exists for an always reliable sealing of said combustion chamber while enduring dimensional manufacturing tolerances of cooperating parts as well as tolerances in cylinder head tightening.

In a reciprocating piston engine having a cylinder block, at least one cylinder head, and at least one replaceable cylinder liner, whereby in each cylinder liner there is slideably disposed a respective piston and a combustion chamber is provided that is delimited by said cylinder head, said cylinder liner, and said piston, with said cylinder liner being supported on said cylinder block via a liner shoulder, and with that end face of said liner shoulder that faces said cylinder head being provided with a first raised edge portion in that portion of said end face contiguous to said combustion chamber, and also being provided with a radially outwardly open recess, which has a base, in the remaining portion of said liner shoulder end face, with the latter further being provided in said recess region with a circumferential second raised portion that is directed toward said cylinder head, whereby a continuous plate-like cylinder head gasket, made of solid metal, is disposed in said recess between said cylinder head and said cylinder block, the improvement in combination therewith wherein:

only said second raised portion, and not said base of said recess, extends and includes a projection having a penetration depth for a distance, in the direction toward said cylinder head, via only said projection for a distance of penetration depth relative to as well as beyond an end face of said cylinder block that faces said cylinder head;
and wherein said cylinder head gasket has a defined compressive strength with full surface seal support between said cylinder head and said cylinder block, and said second raised portion is matched with said cylinder head gasket in such a way that when said cylinder head is secured to said cylinder block, said gasket is always stressed beyond the yield point and is positively interlocked with said second raised portion due to plastic deformation at a quantitatively regulated pressure force dependent exclusively upon flow limit of the gasket in a region of said projection whereas gasket regions to the left and right thereof have no engagement with the cylinder liner, with penetration of said second raised portion into said cylinder head gasket being completed as soon as a remaining portion of said gasket comes into contact with said end face of said cylinder block, and with said cylinder head gasket having such a stress/strain characteristic that once said yield point is exceeded, a maximum, substantially constant compressive strength deformation range exists, the height or projection of said circumferential second raised portion, and the thickness of said metal cylinder head gasket, are such that after installation, an elastically clamped sealing height results that is sufficient, due to elastic spring action, to avoid unacceptable local reductions in bearing pressure, said cylinder head gasket comprising two separate members, namely a sealing ring member that is disposed between said cylinder head and said liner shoulder to effect said interlocking with said circumferential second raised portion, and a further sealing member that is disposed between said cylinder head and said end face of said cylinder block.

Dependencies are inferred from the claim text.