Patent ID: 7533655

Claim:
An internal combustion engine comprising: a variable volume combustion chamber; an air intake system for delivering charge air to the combustion chamber, the air intake system comprising an inlet passage though which air is delivered to the combustion chamber; an exhaust system for relaying combusted gas from the combustion chamber to atmosphere; and a fuel injection system for delivering fuel into the charge air in the inlet passage for combustion therewith in the combustion chamber; wherein the fuel injection system comprises: a plurality of fuel injectors each of which functions as a positive displacement pump and dispenses an amount of fuel which is fixed for each and every operation of the injector; at least a first fuel injector of the plurality of fuel injectors dispensing a first set amount of fuel different to a second set amount dispensed by a second fuel injector of the plurality of fuel injectors; and a controller which controls the operation of each of the plurality of fuel injectors; wherein: in each of at least a majority of engine cycles the fuel injectors are operated on a plurality of occasions by the controller; in response to an increasing engine speed and/or load the controller increases in amount the fuel delivered per engine cycle by increasing in number the occasions the fuel injectors are operated per engine cycle; and in response to a decreasing engine speed and/or load the controller reduces in amount the fuel delivered per engine cycle by reducing in number the occasions the fuel injectors are operated per engine cycle.