GDI Compact Four Stroke Engine - an Advanced Concept for Vehicle Application 2004-01-0039
The development trends of advanced automobile engines towards high power-to-volume and power-to-mass ratios are partially in contradiction with the requirements regarding drastically reduced fuel consumption and pollutant emission. The development way of the engine between customer acceptance and limitations by law is mainly determined by the optimization of scavenging, mixture formation and combustion characteristics, as functional base for the engine design.
The paper presents a new direct injection concept and its optimization correlated with the scavenging process. The process simulation - as a base for the engine development - was carried out using concomitantly two CFD codes - FIRE and VECTIS. The main optimization parameters were the combustion chamber design, the injector location, the spray characteristics, the spark location, the injection timing and duration. This paper is polarized on the analysis of the results using the CFD code VECTIS and on the comparison of both methods.
A main part of the paper is dedicated to the compared engine and vehicle tests using different parameter combinations, as a concrete result of the simulation strategy.
The GDI configuration is compared with previous GDI concepts in base of experimental analysis at the engine test bench, at the vehicle test bench during ECE test cycles, as well as on road.
The results regarding the power-to-volume ratio, the specific fuel consumption, the pollutant emission as well as the acceleration behavior represent a reference for advanced compact engines.