A Study on Cold Emission Reduction of Direct-Injection Gasoline Engine by Controlling the In-cylinder Gas Properties (Third Report)

Abstract

The unburned components that do not contribute to combustion emitted from internal combustion engines should be significantly reduced. In this study, enhancement of a post oxidation under cold conditions was investigated by controlling the in-cylinder gas properties of a directinjection gasoline engine equipped with a variable valve system. The combination of “Late Intake Valve Opening” and “Late Exhaust Valve Opening” functions was verified. The results showed that THC and PN were further improved due to the increased superheat, intake air flow enhancement, and re-burn effect of the exhaust process.