TIMING OF FUEL INJECTED ENGINES

摘要

A method of operating a two-stroke spark ignition engine (9) wherein the fuel is injected directly into the engine combustion chamber (22). The timing of the injection of the fuel and the ignition of the fuel charge are varied according to engine load and speed conditions. Under low load and speed conditions substantially all the fuel is injected after closure of the exhaust port (20) and the fuel charge is ignited between 40 and 70 degrees of crank angle rotation before the top dead centre point of the engine cycle. Under high load conditions substantially all the fuel is injected before exhaust port closure.