| 摘要 |
<p>PURPOSE:To prevent an error diagnosis at a high altitude place, by correcting the specific values responding to the atmospheric pressure, when it is diagnosed whether the EGR is being performed actually or not at the time the EGR is to be performed when the intake pipe pressure and the rotation frequency are at the specific values. CONSTITUTION:To a microcomputer 50, The detected values of a rotation frequency sensor 56, a water temperature sensor 57, an intake pipe pressure sensor 58, and a temperature sensor 59 furnished on the way of an EGR duct 10 are input into a microcomputer 59. And when both the detected values of the rotation frequency sensor 56 and the intake pipe pressure sensor 58 are within the specific ranges, it is diagnosed whether the EGR is being performed actually or not depending on the detected value of the temperature sensor 59. When the rotation frequency is within the specific range and the variation rate of the intake pipe pressure is less than the specific value, the atmospheric pressure is computed depending on the rotation frequency and the detected value of the intake pipe pressure sensor 58, and the specific ranges of the rotation frequency and the intake pipe pressure to be diagnosed responding to the atmospheric pressure are corrected.</p> |
