| 摘要 |
<p>PURPOSE:To heighten the accuracy in deciding the degree of catalyzer deterioration by installing a front oxygen sensor and a rear oxygen sensor on the inlet side and on the outlet side of the catalyzer, respectively, and deciding the degree of deterioration based on a response delay, or a period from a time at which the output of the front oxygen sensor becomes lower than a standard value to another time at which the output of the rear oxygen sensor becomes lower than the standard value, taking almost one half the voltage value, or an amplitude, of each output signal as the standard value common to both sensors. CONSTITUTION:A front oxygen sensor 3 is installed in an exhaust pipe 2 on the inlet side of a catalyzer 1, which purifies exhaust gas from an engine, while a rear oxygen sensor 5 is installed in an exhaust pipe 4 on the outlet side. A catalyzer deterioration deciding device 6 is connected to both oxygen sensors 3, 5 so that the deterioration of the catalyzer can be decided from a response delay of both oxygen sensors. When the fuel supply to the engine is cut, the catalyzer deterioration is decided based on the response delay, or a period from a time at which the output of the front oxygen sensor becomes lower than a standard value to another time at which the output of the rear oxygen sensor becomes lower than the standard value, taking almost one half the voltage value, or an amplitude, of each output signal as the standard value common to both sensors. With this, arithmetic processing can be reduced and the accuracy can be hightened.</p> |
