Development and Validation of a Thermodynamic Model for an SI Single-Cylinder Engine

Abstract

A multizone quasi-dimensional model that illustrates the intake, compression, combustion, expansion, and exhaust processes has been developed for a single-cylinder four-stroke spark-ignition engine. The model takes into consideration mass and energy conservation in the engine cylinder, intake and exhaust plenums, and crank-case plenum. The model calculates instantaneous variations in gas thermodynamic states, gas properties, heat release rates, in-cylinder turbulence, piston ring motion, blowby, nitric oxide, and carbon monoxide formation. The cycle simulation accounts for the induced gas velocities due to flame propagation in the turbulence model (k–ε type), which is applied separately to each gas zone. This allows for the natural evolution of the averaged mean and turbulent velocities in burned and unburned gas regions. The present model predictions of thermal efficiency, indicated mean effective pressure, peak values of gas pressure, ignition delay, concentrations of nitric oxide, carbon monoxide, and carbon dioxide are proven to be in agreement with experimental data.