ABNORMALITY DETECTOR FOR EGR SYSTEM AND METHOD FOR DETECTING ABNORMALITY

摘要

Disclosed is an abnormality detector for facilitating the determination of abnormality in a low-pressure EGR device which supplies EGR gas from a low-pressure EGR passage that connects an exhaust passage on the downstream side of a turbine with an intake passage.  An abnormality detector for an EGR system comprises a high-pressure EGR device connecting an exhaust passage on the upstream side of a turbine with an intake passage, a low-pressure EGR device connecting an exhaust passage on the downstream side of a turbine with an intake passage, and a means for detecting the abnormality of the low-pressure EGR device from the opening of a high-pressure EGR valve when EGR gas is supplied from both the high-pressure EGR device and low-pressure EGR device, and when the high-pressure EGR valve of the high-pressure EGR device is feedback controlled so that the quantity of EGR gas in the cylinder approaches the target range of the quantity of EGR gas while the low-pressure EGR valve of the low-pressure EGR device is open-loop controlled.