Diesel fuel injector with double dump configuration

Claim 2

In a cam driven fuel injector (10) having a fuel inlet port (32) adapted to be connected to a supply or source of fuel and having a drain port (66); including a body (12) defining a bore (14) having a driven or pumping piston (16) reciprocatively situated therein, a metering or floating piston (18) reciprocatively positioned within said bore remote from the pumping piston (16); a timing chamber (20) and a metering chamber (30) defined in the bore and metering and timing chamber dump ports (40, 42) located thereon; a spring cage (22) located remote from said cylinder (14), a spring (58) normally tending to bias a needle valve (52) in a closed position to close off an outflow orifice (54); a plurality of fuel carrying passages (44, 82, 90, 92, 60, 62) for communicating fuel to the metering and timing chambers and from the timing chamber dump port (40) to the spring cage (22) and needle valve (52); the improvement comprising: a spring cage dumping passage (70) communicated between the spring cage (22) and the return port (66) housing, in series, a flow restricting orifice (72) and wherein the metering chamber dump port (42) is communicated directly to the source of fuel.

Claim 3

The fuel injector (10) as defined in Claim 1 further including a single electrically operated control valve (80) for controlling the fuel flow to said timing and metering chambers.

Claim 4

The fuel injector (10) as defined in Claim 2 further including a check valve (74) situated in series with said restricting orifice (72).

Claim 5

The fuel injector (10) as defined in Claim 1 further including a check valve (74) situated in series with said restricting orifice (72).

Claim 6

A fuel infector for an internal combustion engine comprising: a body having an axially extending bore; a primary pumping plunger and a secondary plunger positioned within said body for at least partial axial movement therein; a nozzle situated at the end of said bore remote from said second plunger; a timing chamber defined in said body between said primary pumping plunger and said secondary plunger; a metering chamber defined in said body between said secondary plunger and said nozzle; first passages in said injector for receiving pressurized fuel and transmitting said fuel into said timing chamber and said metering chamber; fuel dump means for dumping the fuel in the timing and metering chambers as a function of the motion of the secondary plunger including fuel dumping ports located on said bore and uncovered by the motion of said secondary plunger including a timing chamber dump port (40) and a metering chamber dump port (42); a spring cage (22), in communication with said timing chamber dump port (40) and adapted to receive a portion of a needle valve (52), containing biasing means (58) for urging said needle valve to prohibit the discharge of fuel therefrom; second passages means (70, 74, 76) for communicating said .spring cage to a drain (66) including, an orifice (72); and third passage means (44, 100) for communicating said metering chamber dump port (42) to either a fuel source or to said drain.

Claim 7

A fuel infector for an internal combustion engine comprising: a body having an axially extending bore; a primary pumping plunger and a secondary plunger positioned within said body for at least partial axial movement therein; a nozzle situated at the end of said bore remote from said second plunger; a timing chamber defined in said body between said primary pumping plunger and said secondary plunger; a metering chamber defined in said body between said secondary plunger and said nozzle; first passages in said injector for receiving pressurized fuel and transmitting said fuel into said timing chamber and said metering chamber; fuel dump means for dumping the fuel in the timing and metering chambers as a function of the motion of the secondary plunger including fuel dumping ports located on said bore and uncovered by the motion of said secondary plunger including a timing chamber dump port (40) and a metering chamber dump port (42); a spring cage (22), in communication with said timing chamber dump port (40) and adapted to receive a portion of a needle valve (52), containing biasing means (58) for urging said needle valve to prohibit the discharge of fuel therefrom; second passages means (70, 74, 76) for communicating said .spring cage to a drain (66) including, an orifice (72); and third passage means (44, 100) for communicating said metering chamber dump port (42) to either a fuel source or to said drain.

Claim 8

The fuel injector as defined in Claim 5 further including: an electromagnetic control element for controlling (1) the timing of the discharge of fuel from the metering chamber through the nozzle and (2) the quantity of fuel stored in said metering chamber subsequent to said discharge of fuel;

Claim 9

The fuel injector as defined in Claim 6 wherein said second passage means (70, 74, 76) includes a check valve (76) in series with said orifice (72).

Claim 10

The fuel injector as defined in Claim 5 wherein said third passage means is connected to said drain and wherein said drain is pressurized.

Claim 11

The fuel injector as defined in Claim 7 wherein said third passage means is connected to said drain and wherein said drain is pressurized.