Effects of Cooled Wall Temperature and HC Concentration on Separation Behavior of PM Deposit Layer in an EGR Cooler

We already found that PM layer deposited on the cooled wall in an EGR cooler was separated from the wall under cold start condition. In this study, effects of cooled wall temperature and hydrocarbon (HC) concentration in exhaust gas on the separation behavior of PM deposit layer in a test EGR cooler were investigated experimentally. As a result, it was found that the PM layers which were deposited with high wall temperature was hard to separate from the wall compared with the layers deposited with low wall temperature during the cold start test. As for the HC concentration in exhaust gas, PM layer deposited in higher HC concentration, which was achieved by addition of diesel fuel to the test exhaust gas, was easily separated during the cold start test.