Influence of Turbulence on Catalytic Combustion in Spark Ignition Engine

The objective of the paper is to study the influence of turbulence on the burning velocity of a lean gas-air mixture at high compression ratio ε = 14.5. In the present work turbulent combustion are examined in conditions very similar to those in the engine. Experiments are carried out in a rapid compression machine. The combustion area in a cylinder is divided into two parts: the main combustion chamber and very small open prechamber containing catalyst with developed surface. The temperature of the catalyst is controlled by means of special electronic device. Special inserts with orifices of different diameters are used to generate turbulence in the main combustion chamber. A piston pushes the mixture through the insert and creates swirl with superimposed different scale of turbulence in this chamber. Mutual influence of turbulence and catalytic ignition on combustion of a lean propane air mixture is extensively examined in special sets of experiments. Pressure records showed substantial increase of the rate of pressure rise under the influence of strong turbulence. The rate of pressure rise increased linearly with concentration of propane varying in a mixture from lean to stoichiometric composition.