Idling-Knock in a Pre-Combustion Chamber Diesel Engine

Abstract

A study of the idling-knock in a Diesel engine of a pre-combustion chamber type was carried out by means of accurate indicator diagrams and measurement of its body-noise. The results obtained may be summerized as follows : (1) The combustion of the fuel which has been blown out in incompletely mixed state from the pre-combustion chamber, brings about an excessively high rate of pressure rise in the main combustion chamber, which is considered as the cause of knocking noise. (2) All the method to prevent the incompletely mixed fuel spray from escaping into the main chamber, for instance, a small burner passage, a large pre-combustion chamber, wide spray angle, large distance from injection nozzle to the passage, etc, are effective for reduction of the knock in idle running. However, these methods are not always suitable for the best performance under heavy load. (3) "Pintaux" nozzle is effective to eliminate the idling-knock without sacrificing the performance under heavy load.