The influence of crevice volumes on HC pollutants in internal combustion engines

Abstract

In the present work, the effect of various parameters on formation of HC pollutants (unburned hydrocarbons) which occurs due to their transition into grooves and crevices of the combustion engine in a light diesel engine was investigated. Numerical calculations for simulation of the combustion chamber were carried out by means of a kind of CFD software called AVL Fire. The computational network field comprised crevice-bearing regions on the cylinder that allowed studying quantity and quality of entities entered the crevices. The effects of crevices and regions among the wall and the cylinder on formation of HC pollutants under different fuel injection methods at basic diesel engines were studied. Single-injection at different times as well as various fuel amounts formed the fuel injection configuration. Formation of HC pollutants occurs after ignition completion and before expansion commencement. It was observed that the highest amount of HC was formed using a retarded fuel injection timetable. At two-step injection, when frequency was increased and injection commenced sooner (advance), formation of HC pollutants was observed to be reduced. Dual injection with small frequency and retarded commencement also led to a significant reduction in HC pollutants formation.