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:
Jul. 31, 2001
Filed:
Mar. 24, 1999
Denso Corporation, Kariya, JP;
Abstract
An engine variable valve timing mechanism is controlled during engine starting to set valve opening overlap of intake and exhaust valves around 30° CA. In this case, internal EGR is actively conducted, fuel burning velocity within a cylinder becomes relatively slow and unburned fuel within the cylinder is emitted to an exhaust pipe to be post-burned. The temperature of exhaust gas is maintained high and catalyst converters in the cold state may be activated quickly by actively implementing such post-burning within the exhaust pipe. Further, ignition timing is retarded, the air-fuel ratio is controlled to a slightly lean ratio and the exhaust valve is advanced. The effect of raising the temperature of exhaust gas by post-burning may be realized more reliably by combining each of these controls.