Patent ID: 7351176

Claim:
A pressure regulator valve assembly for an automotive transmission having a hydraulic pump disposed in fluid communication with a torque converter via a torque converter charge circuit, said pressure regulator valve comprising: a valve piston having a plurality of concentric control diameters formed thereon for regulating the flow of automatic transmission fluid from the hydraulic pump to the torque converter; a compression spring arranged in coaxial relation to said valve piston, said compression spring biasing said valve piston to a closed position in relation to said torque converter charge circuit; and bypassing means integrated within said valve piston, wherein said bypassing means comprises an internal check valve including a cylindrical dowel pin disposed within a valve chamber formed in said valve piston, said dowel pin being spring biased to a closed position in relation to said torque converter charge circuit by a calibrated check valve spring disposed about a vented spring guide positioned in coaxial relation to said dowel pin, said internal check valve releasing hydraulic fluid to the torque converter in response to less hydraulic pressure than is required to open said valve piston against the force of said compression spring.