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. 20, 1999
Filed:
Oct. 16, 1997
Narayanan Sivashankar, Canton, MI (US);
Jing Sun, Novi, MI (US);
Ford Global Technologies, Inc., Dearborn, MI (US);
Abstract
An idle speed control system for a direct injection spark ignition engine controlled to operate in either homogeneous air/fuel modes or stratified air/fuel modes. A desired idle speed is set to optimize fuel economy and avoid rough engine operation during various air/fuel operating modes. During rough idle conditions and non stoichiometric air/fuel operation engine air/fuel is enriched until either rough idle ceases or a rich air/fuel limit is reached. During smooth idle operation, and non stoichiometric air/fuel operation, engine air/fuel is enleaned until either rough idle occurs, a lean air/fuel limit reached, or desired fuel economy attained. After the lean limit is reached, and when operating in a non-stoichiometric non-stratified air/fuel mode, and when not operating at desired fuel economy, ignition timing is advanced until an advance limit is reached and desired idle speed is thereafter decreased.