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. 24, 2004
Filed:
Mar. 26, 1999
Kevin Michael Dougan, Plymouth, MI (US);
Charles Wayne Lewis, Brighton, MI (US);
Richard Francis Olenzek, Farmington Hills, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
An electric motor driven pump has a regulator valve for establishing a system pressure within a predetermined pressure range. The regulator valve has three bias pressures and a spring force imposed thereon. One of the bias pressures assists the spring to increase the system pressure and the other two bias pressures either balance the spring and one bias pressure or lower the system pressure. The one bias pressure is established by an electro-hydraulic control mechanism as a function of operating parameters in a powertrain which uses the fluid pressure from the pump. One of the other bias pressures is equal to system pressure and the last bias pressure is available when a predetermined drive condition is requested in the powertrain. A first electrical switch is activated by fluid pressure from the regulator valve if the system pressure is below the demanded pressure and a second electrical switch is activated by fluid pressure from the regulator valve if the system pressure is above the demanded pressure. The signals regarding the condition of the electrical switches is conveyed to the electro-hydraulic control so that the speed of the electric motor can be properly adjusted.