Reduction of Diesel Idle Knock by EGR

In order to reduce diesel idle knock, the effects of EGR on the idling characteristics were investigated on three 4-stroke cycle engines having three different combustion chambers (precombustion, swirl and direct injection).

It was found that EGR was effective not only for reducing idle knock, but also for decreasing fuel consumption, smoke density and exhaust emissions at idling operation regardless of the type of combustion camber.

The same test results were obtained on a crankcase-scavenged 2-stroke cycle diesel engine (direct injection type) by means of inlet throttling.