Development of a Probabilistic Spark Plug Discharge Model Based on Electric Field Calculation

Abstract

Discharge of electric field generated by a spark plug is one of the most important and influential factors to determine combustion behavior of SI engines, as it initiates flame kernels by supplying energy to the air-fuel mixture. A discharge model is required to analyze this process with the help of numerical simulation. A new probabilistic discharge model has been developed, in which the probability of the breakdown is proportional to the intensity of the local electric field. A wide variety of discharges, such as air gap discharge, surface discharge and branching discharge like corona, can be calculated with the developed model. Consequently a detailed analysis of the process from discharge to combustion can be achieved.