Malfunction detection device null of exhaust air return current

摘要

PURPOSE:To expand the operation conditions which can detect abnormality of an EGR device and improve detection precision so that the condition of deterioration of EGR device can be detected accurately. CONSTITUTION:A combustion condition detection means 1 which detects the combustion condition of engine and a standard combustion condition storage means 2 which stores the standard combustion condition per operation condition of engine are provide. The detected combustion condition and the standard combustion condition which is stored in correspondence to the operation condition of engine at that time are compared by a comparison means 3, and abnormality of EGR is judged by an EGR abnormality judgement means 4 based on the result of comparison.