The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 22, 1991
Filed:
Aug. 22, 1990
Wolfgang V Lippe, Konigswinter, DE;
Sieghart Biederman, Pulheim, DE;
Winfried Schulz, Pulheim, DE;
Hans-Peter Wirtz, Cologne, DE;
Johann Kirchhoffer, Cologne, DE;
Ford Motor Company, Dearborn, MI (US);
Abstract
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.