| 摘要 |
<p>PURPOSE:To constantly and accurately judge an abnormality regardless of whether it occurs at start-up of an engine or after the start-up by judging the abnormality in a cooling water temperature detecting means depending on the cooling water temperature at start-up of the engine, which is related to output property of the cooling water temperature detecting means, and the engine speed after the engine is started. CONSTITUTION:In addition to an engine speed sensor 2 and a cooling water temperature sensor 3, an idle switch 4 for detecting the fully closed state of a throttle valve 6 on an air intake pipe 5, etc., are installed on an internal combustion engine 1. Based on these respective signals, an electronic control device 9 controls an idle speed control valve 8 on a bypass passage 7 bypassing the throttle valve 6. In this case, the elecronic control device 9 stores the cooling water temperature detected at the time when the internal combustion engine 1 is started, by a RAM 9e. Until the judgement of an abnormality is made after the internal combustion engine 1 is started, a CPU 9 judges the abnormality in the cooling water temperature sensor 3 depending on the detected engine speed and the stored cooling water temperature.</p> |
