I.c. engine fuel injection system with a fuel injector functioning as a positive displacement pump, and a mixing chamber

摘要

The fuel injection system delivers fuel to be mixed with charge air for subsequent combustion in a combustion chamber (630) of an internal combustion engine. The fuel injection system comprises a fuel injector (210) which functions as a positive displacement pump and dispenses in each operation thereof a set quantity of fuel; ```a mixing chamber (218) into which the fuel injector dispenses fuel; and a gas supply passage (601) for supplying gas to the mixing chamber (218) to entrain the fuel dispensed into the mixing chamber in a flow of gas which passes through the mixing chamber into the combustion chamber (630). The mixing chamber (218) is connected to the combustion chamber (630) to deliver fuel and gas into the combustion chamber separately from the charge air and a depression in the combustion chamber (630) is used to draw gas through the gas supply passage (601) into the combustion chamber (630). An inlet valve (614) controls flow of charge air into the combustion chamber (630) and the inlet valve (614) is kept closed for an initial part of an intake stroke of the engine so that the depression is created in the combustion chamber (630).