Fuel injector with injection rate control

摘要

A closed nozzle fuel injector (10) is provided which effectively controls the fuel injection flow rate, especially during an initial portion of an injection event, while also permitting accurate control over pilot and/or post injection flow rates at all operating conditions thereby advantageously reducing emissions and combustion noise. The injector (10) includes a rate shaping orifice (72) to restrict fuel flow during an initial portion of an injection event and a rate shaping sleeve (70,200,300) mounted for movement to cause a greater flow of injection fuel during a later portion of the injection event. A damping chamber (96) and orifice (98) are also provided to control movement of the rate shaping sleeve (70,200,300).