DEVELOPMENT AND VALIDATION OF A THERMODYNAMIC MODEL FOR AN SI SINGLE-CYLINDER ENGINE

A multizone quasi-dimensional model that illustrates the intake, compr ession, combustion, expansion, and exhaust processes has been develope d for a single-cylinder four-stroke spark-ignition engine. The model t akes into consideration mass and energy conservation in the engine cyl inder, intake and exhaust plenums, and crank-case plenum. The model ca lculates instantaneous variations in gas thermodynamic states, gas pro perties, heat release rates, in-cylinder turbulence, piston ring motio n, blowby, nitric oxide, and carbon monoxide formation. The cycle simu lation accounts for the induced gas velocities due to flame propagatio n in the turbulence model (k - epsilon type), which is applied separat ely to each gas zone. This allows for the natural evolution of the ave raged 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, conce ntrations of nitric oxide, carbon monoxide, and carbon dioxide are pro ven to be in agreement with experimental data.