COMBUSTION AND EMISSIONS ANALYSIS OF DIFFERENT ALCOHOL BLENDS IN A TWO – STROKE SI ENGINE

Abstract

The automotive industry needs to be in a continuous challenge regarding reduced fuel consumption and reduced emissions driven by both legislation and customer needs. In order to optimize the combustion process the DI-spark ignition engines were developed (DI – direct injection). The advanced gasoline engine technologies include reduced engine friction losses, direct gasoline injection, engine downsizing with turbocharger, variable valve actuation (VVA) and homogeneous charge compression ignition (HCCI). Using alcohols reduce the oil dependency and enables a substantial increase in the gasoline engine fuel efficiency. This concept uses a controlled air – assisted direct injection of alcohol and alcohol blends with gasoline into the engine combustion chamber. The engine will also be operated at higher compression ratios. Increase of fuel efficiency was obtained by increasing the compression ratio. In order to reach these goals some minor changes of the present gasoline engine and its fuelling system were undertaken. This paper presents two methods, which were used to improve the combustion process and its exhaust emission in a two stroke SI engine. Comparisons are made with other engine fuelling systems, regarding the combustion process and the resulting emissions.