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:
Feb. 10, 2009
Filed:
Nov. 21, 2005
Paul D. Stevenson, Ann Arbor, MI (US);
Paul D. Stevenson, Ann Arbor, MI (US);
GM Global Technology Operations, Inc., Detroit, MI (US);
Abstract
A method of controlling a torque-transmitting mechanism in a multi-speed transmission includes providing structure forming a pressurizable reaction chamber at a reaction surface of an apply piston opposing an apply surface of the piston. The reaction chamber is pressurized to a first pressure during engagement of the torque-transmitting mechanism to establish a first speed ratio and a first torque capacity. The reaction chamber is pressurized to a second pressure level during engagement of the torque-transmitting mechanism to establish a second speed ratio and a second torque capacity. Thus, because pressure in the reaction chamber may be controllably varied, a greater reaction pressure is established during the second speed ratio, allowing a greater apply pressure level to be used to establish the second torque capacity. A clutch capacity control system is also provided that allows better control of torque-transmitting mechanisms engagable in different speed ratios to establish different torque capacities.