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:
Jan. 14, 2003
Filed:
Aug. 03, 2000
Denso Corporation, Kariya, JP;
Abstract
A variable valve timing control apparatus is constructed so as to supply hydraulic pressure to an unlocking chamber for unlocking a lock pin only from a retarding chamber. In cranking an engine, a hydraulic pressure control valve is controlled so as to supply the hydraulic pressure only to an advancing chamber and so as not to apply the hydraulic pressure to the unlocking chamber. Thereby, the lock pin is prevented from being unlocked in cranking the engine in advance. After that, control current of a solenoid of the hydraulic pressure control valve is switched to hold current for holding the position of the camshaft phase at the point of time when a time necessary for enabling to supply the hydraulic pressure sufficient to control the camshaft phase from the completion of cranking to supply the hydraulic pressure equally to the both advancing and retarding chambers. Thereby, the hydraulic pressure is supplied also to the unlocking chamber from the retarding chamber and the lock pin is unlocked.