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:
Jun. 28, 2005
Filed:
Jun. 25, 2003
David A. Pierpont, Dunlap, IL (US);
Thomas J. Crowell, Metamora, IL (US);
David A. Pierpont, Dunlap, IL (US);
Thomas J. Crowell, Metamora, IL (US);
Caterpillar Inc, Peoria, IL (US);
Abstract
A method of controlling a variable valve actuation system for an engine is provided. A cam assembly is operated to move an intake valve between a first position and a second position. A parameter indicative of an altitude at which the engine is operating is sensed. A first lookup map is accessed to determine a desired air-to-fuel ratio when the sensed parameter indicates that the engine is operating at an altitude below a first predetermined value. A second lookup map is accessed to determine a desired air-to-fuel ratio when the sensed parameter indicates that the engine is operating at an altitude above the first predetermined value. A desired valve actuation period is determined based on the determined air-to-fuel ratio. The intake valve is prevented from returning to the first position until the end of the determined valve actuation period.