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:
Sep. 03, 1991
Filed:
Jan. 11, 1990
John A Hibner, Coldwater, OH (US);
Carl A Lentz, Mooresville, IN (US);
General Motors Corporation, Detroit, MI (US);
Abstract
Garage shifts are accomplished at shifts from neutral to forward or reverse or between forward and reverse. An off-going clutch is released at the beginning of the shift for shifts between forward and reverse; shifts from neutral have no off-going clutch. The on-coming clutch has a fill time at maximum pressure, a lower increasing pressure ramp to begin engagement as indicated by pullup or pulldown, and a closed-loop control triggered by pullup or pulldown. The closed-loop control commands the pressure to control the turbine speed to a calculated profile to bring the speed to a target value. When the target value is attained the closed-loop control is terminated and maximum pressure is applied. For low speed shifts and for a high speed shift between forward and reverse, the target value is zero. For high speed shifts from neutral the target value may be either above or below the initial turbine speed.