Injection Characteristics and Diesel Knock

Publisher Website
Google Scholar
Abstract
Diesel knock arises from vibrations set up in the engine structure by varying stresses resulting from the changing cylinder pressure during the combustion phase of the cycle. An elementary study of the response of an elastically supported mass to a varying applied force illustrates the connexion between the form of the cylinder-pressure/time relation and the excitation of vibrations in the engine. The dependence of the form of this relation upon fuel properties and injection characteristic is discussed with particular reference to pilot injection systems. Experiments with such systems are described and illustrated by some records of engine vibration and cylinder pressure diagrams. Preliminary quantitative data as to the effect of quantity and timing of the pilot charge on the cylinder pressure diagram are reported. The influence of these factors on ignition delay and maximum rate of increase of cylinder pressure is examined. Under the prevailing experimental conditions, the latter is seen to decrease as the quantity of pilot charge is increased and evidence that this phenomenon is primarily responsible for the reduction of Diesel knock is adduced.

This publication has 0 references indexed in Scilit: