Influence of Thermal Throttling on Spark Ignition Engine Efficiency in Idle and Low Load Modes

Abstract

Improving fuel economy and reducing emissions of pollutants in exhaust gases of vehicles operating in urban conditions is one of the key scientific and technical problems that are receiving significant attention. The efficiency of the internal combustion engine is largely determined by the perfection of the processes that occur during intake, mixture formation, combustion of the air-fuel mixture and exhaust gas emission. Under other equal conditions, it is estimated by the mass of the fresh charge introduced into the cylinder, which, in turn, is determined by the level of pressure losses in the intake system, the temperature of the intake air which affects its density and the backpressure in the engine exhaust system. One of the drawbacks of spark ignition engines, the power of which is regulated by throttling, is the increased fuel consumption in idle and low load modes. Thermal throttling by regulating the intake air temperature can be one of the promising methods for increasing fuel economy and reducing emissions of pollutants in exhaust gases at the above modes. The article presents the results of comparative experimental studies of mechanical throttling and the proposed thermal throttling on a Volkswagen BBY spark ignition gasoline engine in idle and low load modes, the implementation of which is possible through minor design changes in the engine intake system, including in operating conditions.