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. 11, 2001
Filed:
Nov. 22, 1999
Noah D. Manring, Chillicothe, IL (US);
Lifei Yu, Dunlap, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
An electrohydraulic valve control system which enables simultaneous flow and pressure control for operating an implement or other work element associated with a work machine through the use of a single control valve design, the present control system comparing the actual valve output flow rate of the hydraulic fluid flowing through the valve to a desired valve output flow rate and thereafter modifying the input flow rate to the valve based upon the difference between the actual valve output flow rate and the desired valve output flow rate. The desired valve output flow rate is determined based upon the actual load pressure being exerted against the implement or work element and the operator input signal generated by the operator upon activation of an operator input control mechanism used to control the operation of the implement or work element. In this regard, the control system stores a plurality of pressure-flow curves, which determine the desired valve, output flow rate based upon the actual load pressure and the operator input signal. The actual valve output flow rate is determined through the use of a flow sensor, or through the use of a flow rate calculator which uses the output signal from various pressure sensors and a spool displacement sensor to calculate the actual valve output flow rate based upon inputs from the appropriate sensors.