Operating a gasoline engine at constant low temperature conditions: The influence of different fuel droplet sizes

摘要

This paper describes an investigation of one operating point of the transient warm-up curve of a gasoline engine. Coolant liquid and oil of this engine have been cooled down to a constant low level in order to perform detailed measurements and an analysis of this particular warm-up point. The influence of low coolant temperature, different pressure drop in an air-assisted fuel injection system and a variation of ignition angles on specific fuel consumption, exhaust emissions, energy conversion, etc. will be shown. The results show that the suggested test procedure (keeping the coolant temperature at a constant low level) provides the possibility to simulate the behavior of an engine with air-assisted fuel injection during warm-up. During this warm-up period it is desired to run the engine with retarded ignition timing to realize a fast catalyst warm-up. For this case it could be shown that an air-assisted fuel injection can be helpful to reduce HC emission and fuel consumption during this period.