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:
Sep. 20, 1988
Filed:
Jan. 21, 1987
Masahiko Asakura, Wako, JP;
Hiroshi Hasebe, Wako, JP;
Shinichi Kubota, Wako, JP;
Yoshitaka Hibino, Wako, JP;
Koji Kajita, Wako, JP;
Atsushi Totsune, Wako, JP;
Honda Giken Kogyo K.K., Tokyo, JP;
Abstract
A method of detecting abnormality in an air-fuel ratio control system for an internal combustion engine, the air-fuel ratio control system having a proportional control valve arranged in an air supply passage for supplying secondary air therethrough to the engine and controlled in response to an output signal from an oxygen concentration sensor arranged in an exhaust system of the engine in a manner such that its valve opening varies in proportion to the magnitude of driving current supplied thereto. A circuit is provided which includes a first transistor, the proportional control valve, and a second transistor arranged in the order mentioned and serially connected with each other between a power source for supplying a predetermined voltage and ground. A value of voltage at a predetermined location in said circuit is sensed while the first and second transistors are in predetermined states of conduction and non-conduction. It is determined whether there is abnormality in the air-fuel ratio control system, on the basis of the sensed voltage value.