Patent ID: 8235394
Filing Date: 2012-08-07
Classification: F01L

Abstract:
1. A valve stem seal assembly for an internal combustion engine, the engine including a housing separating a lubrication chamber and a combustion chamber, the valve stem seal assembly comprising: a valve guide fixed in the housing and extending between the lubrication chamber and the combustion chamber, said valve guide including a pressure relief channel in an external surface thereof; a valve stem extending through said valve guide between the lubrication chamber and the combustion chamber; and an annular elastomeric body adapted to be disposed around said valve stem, said elastomeric body including a first portion having a sealed engagement with the valve stem and a pressure relief lip extending from said first portion at a first location, said pressure relief lip having a sealing configuration where a free end of the pressure relief lip engages an end face of said valve guide and a venting configuration, said sealing configuration closing a passageway in fluid communication with a combustion chamber of the engine to a lubrication chamber of the engine, said venting configuration lifting from a sealing engagement with said valve guide to open the passageway to the lubrication chamber, a bumper extending axially from said first portion at a second location radially spaced apart from said first location and engaging said end face of said valve guide; wherein said pressure relief lip is operable to open to said venting configuration at a predetermined pressure within the passageway and the combustion chamber to allow excess exhaust gasses to vent from the passageway and the combustion chamber, and said pressure relief lip is operable to close to said sealing configuration after the venting of the excess exhaust gases to prevent fluid from the lubrication chamber from entering the passageway and the combustion chamber.