Abstract: An injection rate shaping nozzle assembly for a fuel injector is provided which includes a closed nozzle valve element and a rate shaping control device including an injection spill circuit for spilling a portion of the fuel to be injected to produce a predetermined time varying change in the flow rate of fuel injected into a combustion chamber. The spill circuit includes a spill passage integrally formed in the nozzle valve element. The rate shaping control may include a spill valve for controlling the spill flow through the spill circuit to create a low injection flow rate followed by a high injection flow rate. The spill passage may communicate with the injector nozzle cavity between injection events or alternatively may be blocked to prevent spill flow between injection events. The rate shaping control device may include a spill accelerating device in the form of a spill chamber formed in the nozzle valve element for creating a rapid increase in the spill flow rate.

Abstract: An injection rate shaping nozzle assembly for a fuel injector is provided which includes a closed nozzle valve element and a rate shaping control device including an injection spill circuit for spilling a portion of the fuel to be injected to produce a predetermined time varying change in the flow rate of fuel injected into a combustion chamber. The spill circuit includes a spill passage integrally formed in the nozzle valve element. The rate shaping control may include a spill valve for controlling the spill flow through the spill circuit to create a low injection flow rate followed by a high injection flow rate. The spill passage may communicate with the injector nozzle cavity between injection events or alternatively may be blocked to prevent spill flow between injection events. The rate shaping control device may include a spill accelerating device in the form of a spill chamber formed in the nozzle valve element for creating a rapid increase in the spill flow rate.

Abstract: A fuel injection rate shaping control system is provided which effectively controls the flow rate of fuel injected into the combustion chamber of an engine to improve combustion and reduce emissions by controlling the rate of pressure increase during injection. The injection rate shaping control system includes a rate shaping control device including a rate shaping transfer passage having a predetermined length and diameter specifically designed to create a desired injection pressure rate shape. In other embodiments of the present invention, two or more rate shaping transfer passages capable of producing distinct rate shapes are packaged in various fuel injection systems to selectively provide various rate shapes depending on operating conditions. Switching valves, i.e., solenoid operated three-way valves, may be used to direct the fuel or timing fluid flow to any one of the rate shaping transfer passages.