Patent ID: 6550455
Filing Date: 2003-04-22
Classification: F02D,F02M

Abstract:
A fuel injection system for an internal combustion engine having multiple combustion chambers and a camshaft for cyclically imparting pressurization energy to, and recovering pressurization energy from, fuel supplied to the engine, comprisinga. a source of fuel at low pressure; b. a first set of unit injectors mounted for injecting fuel at high pressure into the combustion chambers, respectively, of the internal combustion engine, each said unit injector including i. an injector body containing a bore for receiving fuel at low pressure from said source of fuel and an injection orifice in fluid communication periodically with said bore, and ii. a pressurizing plunger mounted for reciprocation within said bore to form a fuel pressurizing chamber from which fuel may be withdrawn at relatively high pressure for injection into a corresponding combustion chamber of the engine through said injection orifice; c. a camshaft linkage for simultaneously reciprocating the pressurizing plungers of a set of at least two unit injectors as the engine camshaft rotates to selectively impart pressurization energy to fuel trapped within said fuel pressurizing chambers when said pressurizing plungers advance and to recover pressurization energy from fuel trapped within said fuel pressurizing chambers when said pressurizing plungers retract; and d. a first interconnecting line for allowing fluidic interconnection of the fuel pressurizing chambers formed within said first set of unit injectors to allow fluidic linkage of the volume of fuel being simultaneously pressurized and depressurized within said interconnected fuel pressurizing chambers of said first set of unit injectors, wherein the total volume of fuel that is fluidically linked together within said first set of synchronized unit injectors substantially exceeds the volume of fuel injected during each injection event to avoid substantial loss of injection pressure during each injection event, and wherein each said unit injector of said first set includes a nozzle control valve having a closed condition for preventing the flow of fuel into the corresponding combustion chamber and an open condition in which fuel from said fluidically connected fuel pressurizing chambers of said first set of unit injectors is allowed to flow into the corresponding combustion chamber through the corresponding injection orifice.