| 摘要 |
An engine ECU of a failure diagnosis system for an EGR device starts the EGR device by opening an EGR valve upon establishment of monitor conditions, detects an actual intake pipe pressure PMON based on a value of a vacuum sensor upon elapse of a predetermine time, calculates an estimated intake pipe pressure PMON using a physical model, cuts the EGR operation by changing the opened state to the closed state of the EGR valve, detects an actual PMOFF based on an input value of the vacuum sensor upon elapse of a predetermined time from cut of EGR, calculates an estimated PMOFF using the physical model, and determines the operation of the EGR device as being normal when a result of comparing a difference between the estimated PMON and estimated PMOFF with a difference between the actual PMON and actual PMOFF is smaller than a predetermined value. |
