| 摘要 |
PURPOSE:To aim at simplifying the structure of a self-diagnosing device, by comparing a detected value by an engine operating condition detecting means upon turning on of an EGR with a detected value upon turning off of an EGR so that an EGR is self- diagnosed with no flow-meter sensor etc. being disposed in an exhaust gas recirculation pipe. CONSTITUTION:During operation of an internal combustion engine A, a control means E judges whether a shut-off means D in an exhaust recirculation pipe C is in the opening operation range or not with the use of a map in accordance with parameters such as, for example, an engine rotational speed, vacuum in an intake-air pipe, etc. in order to check whether the EGR is in its actuating range or not, and also judges whether the internal combustion engine A is in its steady state operating condition or not. When it is judged that the shut-off means is in the opening operation range and the engine is in the steady state operating condition, detections values from an operating condition detecting means F as the shut-off means D is opened or closed, are stored in a memory means G. Further, the thus stored detection values are com pared with each other by means of judging means H. If it is judged that the difference between both values is below a predetermined value, an alarm means I is actuated to inform the drivers concerning the abnormal condition of the EGR. |
