Ford Motor Company Limited

Sieghart Biederman

Johann Kirchhoffer

Winfried Franz-Xaver Schulz

Hans-Peter Wirtz

Wolfgang V Lippe

A control system for a torque converter lock-up clutch operates in a hydraulic circuit having line pressure applied to a lock-up clutch control valve and supplied selectively to a clutch-apply pressure chamber or a clutch-release pressure chamber. The control valve includes a valve spool, four control lands and a valve spring urging the control body to a starting position where the valve directs line pressure to the release pressure chamber and connects the apply pressure chamber to a cooler. When control pressure is applied, the valve spool moves to a shift-up position, supplies line pressure to the apply pressure chamber and connects the release-pressure chamber to an outlet line. A pulse-width modulated solenoid valve varies pressure in the release-pressure chamber by means of a throttle opening in the clutch plate, whereby control pressure is modulated so that force between the friction surfaces of the clutch is reduced to allow clutch slippage.

Growing community of inventors

Pulheim, Germany

Sieghart Biederman