Comparative study of charging system of spark ignition engine

The purpose of investigation was comparison of engine's output while equipped with different types of turbocharging systems. Engine used during research was Toyota's SI engine with displacement of 1296 cm3. Intake and exhaust manifold were modified by introducing fixed and variable geometry turbocharger. The third system was electrically driven charger ensuring both constant and variable boost pressure. Regulatory parameters of fuel injection and ignition system weren't changed. On the basis of carried out research , it was affirmed that there is a possibility of introducing charging system into the engine without changes of mentioned regulatory parameters. Proper choice concerning charging systems allows improving torque characteristic in wide range of engine's rotational speed. Electrically driven charger giving maximum boost pressure provides significant improvement in low engine's speed range, whereas in higher range it is not showing so much advantage. In medium engine's speed range the best result is given by variable geometry turbocharging system. In this application boost pressure had to be reduced to 0.25105 [Pa] in order to provide stable engine's run in all conditions including variable engine's speed and whole range of throttle opening angle.