Patent ID: 7438050
Filing Date: 2008-10-21
Classification: F02D,F02M,Y02T

Abstract:
1. An internal combustion engine comprising: a variable volume combustion chamber; an air intake system for delivering charge air 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 for combustion therewith in the combustion chamber; wherein the fuel injection system comprises: a fuel injector which functions as a positive displacement pump and dispenses an amount of fuel which is fixed for each and every operation of the injector; and a controller which controls the operation of the fuel injector; wherein: in each of at least a majority of engine cycles the fuel injector is 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 injector is operated per engine cycle; 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 injector is operated per engine cycle, and the fuel injector is driven mechanically by a camming surface, the fuel injector comprising a piston biased into engagement with the camming surface by a biasing spring and the piston being displaceable by the camming surface to force fuel out of the fuel injector, the camming surface comprising a plurality of cam lobes each of which can interact with the piston during each engine cycle and the controller controlling how many of these cam lobes in each engine cycle cause the piston to force fuel out of the fuel injector.