Reduction of Idle Knock by EGR in a Passenger Car Diesel Engine

In order to reduce the diesel idle knock, the effects of EGR on the idling characteristics were investigated on a passenger car equipped with an EGR Idle Knock Reduction System developed for practical use. It was found that EGR was effective not only for reducing idle knock but also for decreasing fuel consumption, smoke density, exhaust emissions and engine vibration. Moreover, the practical range and possibility of the EGR Idle Knock Reduction System were found by clarifying the relationship between EGR, injection timing, cooling water temperature, noise level and fuel consumption.