Technical Paper
Simulation of HC-Emissions from SI-Engines - A Parametric Study
1997-10-01
972893
Earlier modelling of SI engine HC-emissions indicated that the absorption/desorption of fuel HC in the oil film played a rather important role for the engine-out HC-emissions. However, recent experimental results seem to indicate that this mechanism does not play a major role. Therefore, we updated a previous model in order to obtain a better understanding of the absorption/desorption phenomenon. The upgraded absorption/desorption model has been combined with the MIT ring/liner lubrication model and applied to a single cylinder engine with known lubrication characteristics. The calculations have been carried out for steady-state and warm-up conditions. Compared to earlier results we found that due to an essentially smaller oil film thickness calculated by the lubrication model the absorption/desorption process exhibits a much faster response than previously estimated.