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:
Jan. 14, 1986
Filed:
Oct. 30, 1984
Takao Akatsuka, Toyota, JP;
Jiro Nakano, Toyota, JP;
Takao Ishibashi, Toyota, JP;
Masao Kawaguchi, Toyota, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Abstract
An internal combustion engine has an exhaust system and an oxygen sensor fitted to the exhaust system including a sensor element and an electrically powered heater for heating the sensor element. A method is disclosed for controlling the air/fuel ratio of the air-fuel mixture supplied to the engine, by, when the voltage of the power supply to the heater has dropped below a first predetermined value and thereafter has remained below a second predetermined value higher than the first predetermined value for longer than a predetermined time period, controlling the air/fuel ratio according to engine operational parameters by an open loop form of control with no account being taken of the output signal of the oxygen sensor, and otherwise controlling the air/fuel ratio according to these engine operational parameters by a closed loop form of control taking into account the output signal of the oxygen sensor so as to obtain an optimum air/fuel ratio for the engine by a feedback control process. Accordingly it is ensured that the air/fuel ratio of the engine is kept appropriate, even if the voltage of the battery drops so low that it can no longer properly power the oxygen sensor heater, which causes the output signal of the oxygen sensor to be no longer reliable for indicating the amount of oxygen in the exhaust gases of the engine. A system is also described for implementing this method.