Analysis of the potential of a new automotive two-stroke gasoline engine able to operate in spark ignition and controlled autoignition combustion modes

Abstract

The need to reduce the emissions coming from automobiles encourages the attempts to study different engine configurations and new combustion strategies. In this case, a two stroke engine able to operate in Controlled AutoIgnition (CAI) and Spark Ignition (SI) combustion modes is studied, with the purpose of getting lower NOx and CO2 emissions than with other currently employed solutions. The engine configuration retained for the research is a uniflow scavenging configuration with intake ports in the cylinder liner and exhaust valves in the cylinder head. These valves are controlled by a Variable Valve Timing (VVT) system. The scavenging is guaranteed by an external blower driven by the crankshaft. Finally, the fuel supply is performed by a direct injection (DI) air-assisted fuel injection system.Through this paper the adjusting parameters to control the engine operation, as well as their influence on the CAI and SI combustion modes have been studied, providing the most relevant information and knowledge for controlling and optimizing the engine performance. Once these controlling parameters were studied, an EGR system was introduced in order to analyze the effect of this other parameter over the combustion process, as well as to determine the potential benefits of introducing such a system in this type of engines.