A Thermodynamic Model for a Single Cylinder Engine with Its Intake/Exhaust Systems Simulating a Turbo-Charged V8 Diesel Engine

摘要

In this paper, a thermodynamic model is discussed for a single cylinder diesel engine with its intake and exhaust systems simulating a turbo-charged V8 diesel engine. Following criteria are used in determination of the gas exchange systems of the single cylinder engine (SCE): 1) the level of pressure fluctuations in the intake and exhaust systems should be within the lower and upper bounds of those simulated by the thermodynamic model for the V8 engine and patterns of the pressure waves should be similar; 2) the intake and exhaust flows should be reasonably close to those of the V8 engine; 3) the cylinder pressures during the combustion and gas exchange should be reasonably close to those of the V8 engine under the same conditions for the valve timing, fuel injection, rate of heat release and in-cylinder heat transfer. The thermodynamic model for the SCE is developed using the 1D engine thermodynamic simulation tool AVL BOOST. Besides the pipelines in the conventional intake and exhaust systems, additional pressure wave tuning pipes are added, with which the intake and exhaust systems for the SCE can be tuned to simulate the gas dynamics in the V8 engine. With the tuned intake and exhaust systems, the simulated gas dynamics for the intake and exhaust flows become very similar to those predicted by the thermodynamic model for the V8 engine. Based on the layouts specified in the SCE model, the intake and exhaust systems for the SCE were developed. Good agreements are observed between the simulated and measured intake and exhaust pressures of the SCE.