Fuel injector and common rail fuel supply system

A fuel injector for use in an internal combustion engine having combustion chambers and a fuel supply including a supply rail and a fuel pressure regulator for regulating the fuel pressure in the rail within a range of pressure from a low value to a high value, comprising an injector body having a fuel chamber formed therein, said chamber being adapted to receive fuel under pressure from said supply rail, said body further having a nozzle formed therein which connects said fuel chamber with a combustion chamber of the engine, a pintle-type valve member movably mounted in a fuel flow area in said body adjacent said nozzle, said member being movable to one position where it closes said nozzle and to other positions where said fuel flow area from said chamber to said nozzle is at least partially open, said valve member having a surface area thereof exposed to the pressure of the fuel in said fuel chamber, whereby a fuel force is applied on said member to urge said member away from said one position, said fuel force being a function of said surface area and the pressure of the fuel in said fuel chamber, first force applying means operative to urge said member toward said one position and related to said fuel force such that said member is moved out of said one position at said low pressure valve and the amount of movement varies and is a function of said fuel pressure, and the amount of said movement varying the size of said fuel flow area, second force applying means operative to urge said member toward said one position, the sum of the forces of said first and second force applying means being greater than said fuel force at said high pressure value, and control means for periodically removing said second force applying means from said valve member.

A fuel supply system for an internal combustion engine including a plurality of combustion chambers, comprising an injector for direct injection into each of said chambers, common rail fuel supply means for supplying fuel under pressure to said plurality of injectors and for regulating said pressure in a range of pressures, each of said injectors including body means forming a fuel flow passage and a valve seat, a valve member cooperable with said valve seat to control the flow area of said fuel flow passage, first force applying means urging said valve member to engage said seat and thereby to close said passage, control means enabling movement of said valve member away from said seat during a time period in each cycle, said valve member being movable away from said seat and having a surface area exposed to the pressure of said fuel and the force of the pressure on said surface area moving said valve member against said force applying means to open said passage during the entire time period, said surface area, the force of said force applying means, and said pressure range being related to cause said member to move away from said seat to a position that is a function of the fuel pressure, and the position of said member relative to said seat being determinative of the size of the flow area, whereby said common rail fuel pressure controls the size of said flow area and fuel is injected for said entire time period and in an amount that is a function of said rail pressure.