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:
Apr. 22, 2008
Filed:
May. 17, 2007
Thompson M. Sloane, Oxford, MI (US);
Tang-wei Kuo, Troy, MI (US);
Jun-mo Kang, Ann Arbor, MI (US);
Paul M. Najt, Bloomfield Hills, MI (US);
Thompson M. Sloane, Oxford, MI (US);
Tang-Wei Kuo, Troy, MI (US);
Jun-Mo Kang, Ann Arbor, MI (US);
Paul M. Najt, Bloomfield Hills, MI (US);
GM Global Technology Operations, Inc., Detroit, MI (US);
Abstract
The invention provides a method for operating a multi-cylinder, spark-ignition, direct-injection, four-stroke internal-combustion engine adapted to operate in a controlled auto-ignition mode selectively operative at stoichiometry and lean of stoichiometry. The method comprises adapting an engine valve actuation system to control engine valve opening and closing, and monitoring engine operating conditions and ambient barometric pressure. The engine is operated unthrottled and the engine valve actuation system is controlled to effect a negative valve overlap period when the engine operating conditions are within predetermined ranges. A mass of fuel is injected during the negative valve overlap period. The magnitude of the negative valve overlap period is decreased with decreasing ambient pressure and increased with increasing ambient pressure.