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:
Dec. 09, 1997
Filed:
Dec. 26, 1996
Yasumasa Kaji, Toyota, JP;
Denso Corporation, Kariya, JP;
Abstract
To provide a water temperature sensor failure detecting device for an idle speed control system of an internal combustion engine which eliminates the need for a bimetallic guard mechanism, an aperture characteristic of an idle control valve (ISCV) when normal becomes a larger degree of opening as coolant water temperature drops, and bypass airflow supplied to an engine is increased. During failure of a water temperature sensor, a duty value for driving the ISCV is set at 50%, the ISCV is opened substantially halfway, and the bypass airflow supplied to the engine is caused to be a neutral flow. In this way, by causing the bypass airflow during failure of the water temperature sensor to be a neutral flow, a worst state of overrun, engine stall and the like can be prevented, and startability when at low temperature and operability after engine warmup can be ensured.