Constructive parameters analysis of combustion pre-chamber adapted in torch-ignition system of Otto cycle engine

摘要

The torch ignition system consists of the inflammation of the air/fuel mixture by means of gases jet flames that constitute ignition lines. Engines with this feature have a cavity or combustion pre-chamber, physically separate from the main chamber. In these systems a larger turbulence generation happens, due the movement of the gases inside the pre-chamber and through the interconnection orifices. The charge stratification, by means of an auxiliary inlet fuel system, also contributes for the fast and insurance inflammation of lean mixtures and the most varied combustible, including the difficult direct spark ignition fuels. This work presents the design elaboration of combustion pre-chamber from an analysis of the influence of the main constructive parameters in the combustion process. The volume of the pre-chamber, the pattern of the interconnection orifices with the main chamber and the pre-chamber geometry, amongst other parameters, influence significantly in the efficiency of the combustion and consequently the efficiency of the engine and the pollutants emissions. The reduction of the pollutants emissions, the reduction of the brake specific fuel consumption and the increase of the global efficiency of the engine are the main benefits obtained with the torch ignition.