Valve stem seal with gas relief features

A valve stem seal assembly for an internal combustion engine, the engine including a housing separating a lubrication chamber and a combustion chamber, a valve guide fixed in the housing, and a valve stem extending through the valve guide and housing between the lubrication chamber and the combustion chamber, the valve stem seal assembly comprising:

• an annular rigid body and an annular elastomeric body both disposed around the valve guide and the valve stem, said elastomeric body including a first portion having a sealed engagement with the valve stem, a second portion extending around the valve guide, a connecting portion extending radially outwardly from said first portion to said second portion, and a pressure relief lip extending from said second portion, said second portion including a plurality of spaced apart axially extending protrusions extending radially inward from an inner surface thereof and adapted to engage the valve guide and a plurality of axially extending channels discretely formed between the inner surface and a pair of adjacent protrusions of the plurality of axially extending protrusions, each channel forming part of the passageway and spaced apart circumferentially around the inner surface of said second portion such that each channel is adapted to directly face said valve guide, said pressure relief lip having a sealing configuration and a venting configuration, said sealing configuration adapted to close a passageway in fluid communication with the combustion chamber to the lubrication chamber, said venting configuration adapted to open the passageway to the lubrication chamber, said pressure relief lip extending radially inward from said second portion such that a free end of said pressure relief lip has a smaller inner diameter than an opposite end connected to said second portion in said sealing configuration;
• 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 gases 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.

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;
• a valve stem extending through said valve guide between the lubrication chamber and the combustion chamber;
• and
• an annular rigid body and an annular elastomeric body both disposed around said valve guide and said valve stem, said elastomeric body including a first portion having a sealed engagement with said valve stem, a second portion extending around said valve guide, a connecting portion extending radially outwardly from said first portion to said second portion and spaced axially apart from an upper surface of said valve guide, and a pressure relief lip extending from said second portion, said pressure relief lip having a sealing configuration and a venting configuration, said sealing configuration adapted to close a passageway in fluid communication with the combustion chamber to the lubrication chamber, said venting configuration adapted to open the passageway to the lubrication chamber, said second portion including a plurality of axially extending protrusions extending radially inward from an inner surface thereof and spaced apart circumferentially around the inner surface and a plurality of axially extending channels discretely formed between the inner surface and a pair of adjacent protrusions of the plurality of axially extending protrusions, each channel forming part of the passageway and spaced circumferentially around the inner surface such that each channel directly faces said valve guide, said pressure relief lip extending radially inward from said second portion such that a free end of said pressure relief lip has a smaller inner diameter than an opposite end connected to said second portion in said sealing configuration;
• 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 fluids 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 fluids to prevent fluid from the lubrication chamber from entering the passageway and the combustion chamber.