Patent ID: 8011669
Filing Date: 2011-09-06
Classification: F01L

Abstract:
1. A valve stem seal for an internal combustion engine, the valve stem seal comprising: an annular elastomeric body disposed around a valve stem and a valve guide for the engine, 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 connecting portion adapted to be axially spaced apart from an upper end of 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 a combustion chamber of the engine to a lubrication chamber of the engine, said venting configuration adapted to open the passageway to the lubrication chamber, 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 adapted to form part of the passageway and spaced circumferentially around the inner surface of said second portion such that each channel is adapted to directly face 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 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.