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. 25, 1995
Filed:
Jan. 27, 1994
Franz A Lieder, White Lake, MI (US);
Gregory E Labus, Flint, MI (US);
Gary A Nichols, Farmington Hill, MI (US);
Stephen D Matteson, Byron, MI (US);
Myron H Bell, Highland, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
An idle air control system diagnostic for an internal combustion engine which utilizes RPM, engine timing and intake airflow measurements to detect the presence of idle RPM faults and eliminate or verify the idle air control system as the fault source. Engine idle RPM is measured and compared with a commanded idle RPM, and if within a predetermined range, an idle RPM fault exists and one of two additional tests (non-intrusive and intrusive) is conducted to determine whether the idle air control system is the source of the fault. In the non-intrusive test, intake airflow is measured and compared to a predetermined intake airflow value, and if not within a predetermined range, the idle air control system is determined to be the fault source. In the intrusive test, variations in intake airflow (or intake manifold pressure) are measured in response to variations in the movement of the engine throttle-bypass airway pintle. If no intake airflow variations are detected, the idle air control system is determined to be the fault source.