| 摘要 |
<p>The process comprises determining the temperature coefficient before and after a treatment unit (28) in a motor vehicle IC engine exhaust system (22) and comparing the temperature coefficient after the unit with a threshold value to detect the absence of a treatment unit from the temperature coefficient measured before the unit. Each time the threshold value is exceeded the data is fed to a computer which determines from a second threshold value when the treatment unit is absent or not functioning.</p> |
