Effect of Lean Pre-Mixture on the Combustion in Diesel Engine : 1st Report, Fundamental Experiments

Abstract

By investigation of the chemical reacting behaviour of the pre-mixture, it has been made clear that radical precursors and intermediates produced by the decomposition of the pre-mixture are responsible for the combustion of main fuel. In this paper, the influences of different organic ompounds as an auxiliary fuel are investigated on the ignition lag, the pressure diagram, the flame luminosity, the smoke density etc. W come to the following conclusions : (1) The organic compound which contains some hydrogens of weak bond-strength may be favorable for lean pre-mixture. (2) Using such a fuel as alcohol or n-paraffin, which is prone to free radical, as the auxiliary fuel, the flame of main combustion has a poor luminosity. (3) There is little difference in the effects of lean pre-mixture on the exhaust smoke among the fuels investigated. In the case of pre-mixing with a constant quantity of main fuel, the soot formation will be suppressed as much as the amount corresponding to the lean pre-mixture or more.