Oxygen sensor deterioration-detecting device for internal combustion engines
AssigneeHonda Giken Kogyo Kabushiki Kaisha
InventorsHiroshi Maruyama, Tsuyoshi Takizawa, Toshihiko Sato, Hiroshi Ito, Yasunari Seki, Takayoshi Nakayama
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Abstract
The air-furl ratio of an air-fuel mixture supplied to an internal combustion engine is controlled in response to an output from at least one oxygen sensor arranged in an exhaust passage for detecting concentration of oxygen present in exhaust gases. The deterioration of the at least one oxygen sensor is detected based on the output therefrom. When the engine is detected to be in a predetermined abnormal operating state, it is not permitted to monitor the output from the oxygen sensor for detecting deterioration thereof.
Claims23
In an oxygen sensor deterioration-detecting device for an internal combustion engine having an exhaust passage, a catalytic converter arranged in said exhaust passage for purifying exhaust gases from said engine, an oxygen sensor arranged in said exhaust passage for detecting concentration of oxygen in said exhaust gases, and air-fuel ratio control means responsive to an output from said oxygen sensor for controlling the air-fuel ratio of an air-fuel mixture supplied to said engine, said oxygen sensor deterioration-detecting device including oxygen sensor deterioration-detecting means for detecting deterioration of said oxygen sensor based on an output from said oxygen sensor,
- the improvement comprising:
- engine operating condition-detecting means for detecting operating conditions of said engine, said engine operating condition-detecting means including said oxygen sensor;
- abnormal state-determining means for determining that said engine is in a predetermined abnormal operating state, based on an output from said engine operating condition-detecting means;
- and
- deterioration detection-inhibiting means for inhibiting said oxygen sensor deterioration-detecting means from detecting said deterioration of said oxygen sensor when said predetermined abnormal operating state of said engine is detected.
In an oxygen sensor deterioration-detecting device for an internal combustion engine having an exhaust passage, a catalytic converter arranged in said exhaust passage for purifying exhaust gases from said engine, a first oxygen sensor and a second oxygen sensor arranged in said exhaust passage at respective locations upstream and downstream of said catalytic converter for detecting concentration of oxygen in said exhaust gases, and air-fuel ratio control means responsive to outputs from said first oxygen sensor and said second oxygen sensor for controlling the air-fuel ratio of an air-fuel mixture supplied to said engine, said oxygen sensor deterioration-detecting device including oxygen sensor deterioration-detecting means for detecting deterioration of said first oxygen sensor based on an output from said first oxygen sensor,
- the improvement comprising:
- engine operating condition-detecting means for detecting operating conditions of said engine, said engine operating condition-detecting means including said first oxygen sensor and said second oxygen sensor;
- abnormal state-determining means for determining that said engine is in a predetermined abnormal operating state, based on an output from said engine operating condition-determining means;
- and
- deterioration detection-inhibiting means for inhibiting said oxygen sensor deterioration-detecting means from detecting said deterioration of said first oxygen sensor when said predetermined abnormal operating state of said engine is detected.
Dependencies are inferred from the claim text.