Fuel injection rate shaping control system

A fuel system for supplying fuel at a predetermined pressure to the corresponding cylinders of a multi-cylinder internal combustion engine to define respective injection events, comprising:

• a fuel supply means for supplying fuel for delivery to the internal combustion engine, said fuel supply means including a fuel transfer circuit;
• a pump means for pressurizing fuel above the predetermined pressure;
• an accumulator means for accumulating and temporarily storing fuel at high pressure received from said pump means;
• an injection control valve means positioned within said fuel transfer circuit between said accumulator means and the internal combustion engine for controlling the fuel injected into each engine cylinder during respective injection events;
• a rate shaping control means positioned along said fuel transfer circuit between said accumulator means and said injection control valve means for producing a predetermined time varying change in the pressure of fuel occurring sequentially at each engine cylinder to effect injection, said rate shaping control means including a plurality of rate shaping devices positioned in parallel relative to the flow of fuel from said accumulator and a switching valve means for selectively directing fuel flow from said accumulator means through one of said plurality of rate shaping devices during an injection event, wherein fuel flow from said accumulator during an injection event occurs through only one of said rate shaping devices.

A fuel system for supplying fuel at a predetermined pressure to the corresponding cylinders of a multi-cylinder internal combustion engine to define respective injection events, comprising:

• a fuel supply means for supplying fuel for delivery to the internal combustion engine, said fuel supply means including a fuel transfer circuit;
• a pump means for pressurizing fuel above the predetermined pressure;
• an accumulator means for accumulating and temporarily storing fuel at high pressure received from said pump means;
• an injection control valve means positioned within said fuel transfer circuit between said accumulator means and the internal combustion engine for controlling the fuel injected into each engine cylinder during respective injection events;
• a rate shaping control means positioned along said fuel transfer circuit between said accumulator means and said injection control valve means for producing a predetermined time varying change in the pressure of fuel occurring sequentially at each engine cylinder to effect injection, said rate shaping control means including a plurality of rate shaping transfer passages associated with each engine cylinder and positioned in parallel relative to fuel flow from said accumulator and a switching valve means for selectively directing fuel flow from said accumulator means through only one of said plurality of rate shaping transfer passages during an injection event.

A metering system for metering and timing of fuel injection in the combustion chambers of a multi-cylinder internal combustion engine comprising:

• a fluid supply means for supplying fuel and timing fluid at a low supply pressure, said fluid supply means including a timing fluid accumulator, a timing fluid transfer circuit fluidically connected to said timing fluid accumulator and a fuel metering transfer circuit;
• one or more fuel injectors positioned adjacent respective combustion chambers for receiving fuel at the low supply pressure and for injecting the fuel at relatively high pressure into respective combustion chambers of the engine, each of said one or more injectors including an injector body containing an injector cavity, an injector orifice formed at one end of the injector body and a plunger means mounted for reciprocal movement in said injector cavity, further including a variable volume timing chamber formed in said injector cavity adjacent a first end of said plunger means and a variable volume metering chamber formed adjacent an second end of said plunger means opposite said first end between said injector orifice and said plunger means;
• a fuel metering means positioned in said fuel metering transfer circuit for controlling the flow of fuel to said metering chamber;
• a timing fluid control valve positioned in said timing fluid transfer circuit between said timing fluid accumulator and said one or more injectors for controlling the flow of timing fluid to said timing chamber, said timing fluid control valve being movable between an open position wherein timing fluid may flow therethrough to said timing chamber and a closed position wherein fluid is blocked from flowing therethrough to said timing chamber, wherein timing fluid in said timing chamber acts on said plunger means when said timing fluid control valve is in said open position to force said plunger means toward said metering chamber;
• a rate shaping control means positioned along said timing fluid transfer circuit between said timing fluid accumulator and said timing fluid control valve for producing a predetermined time varying change in the pressure of fuel occurring sequentially at each engine cylinder to effect injection.