Insulated oil cooled piston assembly
First Claim
1. An oil cooled piston assembly for an internal combustion engine, said assembly comprisinga body member having an outer generally cylindrical ring belt section connected near its upper edge with a depending cup shaped supporting wall integral with a piston pin connecting section below said wall, said wall and said ring belt section defining an annular cooling oil cavity therebetween for receiving cooling oil to cool said ring belt section, said wall defining inwardly thereof a cup shaped recess having a closed bottom forward by said piston pin connecting section and adapted to receive an axially symmetrical insert, anda separate combustion bowl member received within said recess, said bowl member having a depending columnar section with an open bottom received against the bottom of said recess, a central bowl section extending inwardly from the upper edge of the columnar section and closing the top thereof to form a central chamber without direct cooling by coolant in said cooling oil cavity, and a peripheral bowl section extending outwardly and upwardly from said columnar section upper edge,said peripheral bowl and columnar sections together defining a continuous outwardly and upwardly flared inner wall generally parallel to said body member supporting wall, said walls being in engagement at their lower ends and spaced apart intermediate their ends to define an insulating air gap to limit heat loss from the combustion bowl member to the oil cooled wall of the body member.
1 Assignment
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Accused Products
Abstract
An oil cooled diesel engine piston is designed to restrict heat loss from the combustion chamber through provision of a combustion chamber insert defining a central non-oil-cooled chamber and a surrounding annular insulating air gap. The air gap controls heat flow primarily between the combustion gas exposed wall of the insert and an adjacent coolant exposed wall of the main piston volume.
The insert is press fitted into a recess in the main piston body and is positively locked therein by a retaining ring. A seal ring closes expansion clearance provided at the upper edge of the insert against significant gas flow into the insulating air gap. Insulating efficiency of the air gap is maximized by forming the gap with a thickness throughout a major portion of its extent of between about 0.040 and 0.060 inches.
Numerous additional features are also disclosed.
28 Citations
6 Claims
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1. An oil cooled piston assembly for an internal combustion engine, said assembly comprising
a body member having an outer generally cylindrical ring belt section connected near its upper edge with a depending cup shaped supporting wall integral with a piston pin connecting section below said wall, said wall and said ring belt section defining an annular cooling oil cavity therebetween for receiving cooling oil to cool said ring belt section, said wall defining inwardly thereof a cup shaped recess having a closed bottom forward by said piston pin connecting section and adapted to receive an axially symmetrical insert, and a separate combustion bowl member received within said recess, said bowl member having a depending columnar section with an open bottom received against the bottom of said recess, a central bowl section extending inwardly from the upper edge of the columnar section and closing the top thereof to form a central chamber without direct cooling by coolant in said cooling oil cavity, and a peripheral bowl section extending outwardly and upwardly from said columnar section upper edge, said peripheral bowl and columnar sections together defining a continuous outwardly and upwardly flared inner wall generally parallel to said body member supporting wall, said walls being in engagement at their lower ends and spaced apart intermediate their ends to define an insulating air gap to limit heat loss from the combustion bowl member to the oil cooled wall of the body member.
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3. An oil cooled piston assembly for an internal combustion engine, said assembly comprising
a body member having an outer generally cylindrical ring belt section connected near its upper edge with a depending cup shaped supporting wall integral with a piston pin connecting section below said wall, said wall and said ring belt section defining an annular cooling oil cavity therebetween for receiving cooling oil to cool said ring belt section, said wall defining inwardly thereof a cup shaped recess having a closed bottom formed by said piston pin connecting section and adapted to receive an axially symmetrical insert, and a separate combustion bowl member received within said recess, said bowl member having a depending columnar section with an open bottom received against the bottom of said recess, a central bowl section extending inwardly from the upper edge of the columnar section and closing the top thereof to form a central chamber without direct cooling by coolant in said cooling oil cavity, and a peripheral bowl section extending outwardly and upwardly from said columnar section upper edge, said peripheral bowl and columnar sections together defining a continuous outwardly and upwardly flared inner wall generally parallel to said body member supporting wall, said walls being in engagement at their lower ends and spaced apart intermediate their ends to define an insulating air gap to limit heat loss from the combustion bowl member to the oil cooled wall of the body member, said walls being spaced with close clearance near their upper ends and further including high temperature seal means between said walls at and substantially closing said close clearance to deter significant gas leakage into said insulating air gap.
Specification