| 摘要 |
<p>PURPOSE:To make it possible to detect performance degradation of catalytic converter early, by detecting the exhaust gas temperatures on both upper and lower courses of a catalytic converter in an intake air system, and detecting degradation of the catalyst in comparison with those exhaust gas temperatures. CONSTITUTION:The first and the second thermo-couples 3, 4 are respectively disposed on both upper and lower course sides of a catalytic converter 2 interposed on the way of an exhaust gas pipe 1, so that the exhaust gas temperatures T1, T2 in front and rear of the catalyst detected by those thermo-couples 3, 4 are inputted to a trouble diagnosing means 7 through each of signal processing means 5, 6. And it is judged whether or not both exhaust gas temperature T1, T2 are nearly equal to each other, namely, a catalytic activating temperature or not in this trouble diagnosing means 7. At the time of judging as YES, the temperature T2 judged as the catalytic activating temperature, is compared with a temperature TR which is set beforehand as a reference activating temperature, and at the time of T2>TR it is judged that the catalytic converter 2 is degraded and a trouble alarm means 8 is operated.</p> |
