Compression self-igniting gasoline engine

Abstract

Stroke cycles of a self-igniting gasoline engine (,) comprising an intake stroke, compression stroke, power stroke and exhaust stroke are performed sequentially by a piston (,), and self-ignition of the fuel mixture is performed by compression of the fuel mixture in the compression stroke. The strokes of the piston (,) are detected by a sensor (,), and an electronic control unit (,) controls a valve timing adjustment mechanism (,) so that a sealed period occurs when both an exhaust valve (,) and intake valve (,) are closed in the vicinity of top dead center of the exhaust stroke. The electronic control unit (,) also controls the fuel injection timing of a fuel injector (,) so that fuel is injected into the combustion chamber (,) during the sealed period. The fuel injected into the hot gas in the sealed combustion chamber (,) causes pre-combustion reactions, and thereby modifies the gasoline composition to a more reactive composition containing aldehydes so that compression self-ignition occurs easily.