Patent ID: 6904893

Claim:
A fuel injection method in a fuel injection system, said fuel injection system comprising: a fuel injection nozzle including a fuel reservoir and a needle valve; an accumulator which accumulates fuel at a predetermined pressure; a fuel line through which the fuel reservoir and the accumulator are connected; a pressure cutoff valve which is provided along the fuel line, for cutting off fuel pressure flow from the fuel injection nozzle to the accumulator; an injection control fuel chamber which is connected to the fuel line at a downstream side of the pressure cutoff valve; an injection control valve which performs fuel injection by closing the needle valve due to an action of a fuel pressure upon the injection control fuel chamber and by opening the needle valve due to removal of fuel from the injection control fuel chamber; an intensifier which is connected to the fuel injection nozzle and the injection control fuel chamber at a downstream side of the pressure cutoff valve; and intensifier control means which increases a fuel pressure at a downstream side of the pressure cutoff valve by operating the intensifier, said fuel injection method comprising the steps of: suspending operation of the intensifier control means; and performing an after injection of fuel at an intermediate pressure between a predetermined pressure of the accumulator and a static maximum pressure which is statically determined due to operation of the accumulator and the intensifier.