Vacuum relief valve

Abstract

A vacuum relief valve for use with internal combustion engines is provided. The valve is connected to the breathing tubes of an engine on one side and to the air induction system of the engine on the opposite side. Under certain conditions during engine operation, the induction system has a tendency to reduce the pressure within the crankcase creating a partial vacuum. The vacuum relief valve is interposed between the induction system and the crankcase and control or limits the amount of partial vacuum thus created to a maximum of seven inches of vacuum or less. This is accomplished by providing means for limiting the size of a passageway through the valve and thereby limit the amount of suction that can be communicated by the induction system to the crankcase. In one embodiment, a spring biased piston is used to control the size of the passageway. Other valving mechanisms are also contemplated. An auxiliary pathway to atmosphere is also incorporated into the valve so that the breather tubes can be vented when the passageway through the valve is partially or fully closed.

Dependencies are inferred from the claim text.