Claims:We Claim

1. A common rail (10) for an engine, said common rail (10) comprising:
a fuel storage chamber (12);
a throttle (14) in flow communication with said fuel storage chamber (12), said throttle (14) comprising:
a bottom valve insert (16);
a first top valve insert (18) and a second top valve insert (20); characterized in that
a sleeve (22) positioned between said bottom valve insert (16) and between said first top valve insert (18) and said second top valve insert (20), said sleeve (22) adapted to translate within a bore (24) defined between said first top valve insert (18) and said second top valve insert (20).

2. The common rail (10) for an engine in accordance with Claim 1 wherein said sleeve (22) comprises a tapered shank portion (26), said tapered shank portion (26) adapted to translate within the bore (24) defined between said first top valve insert (18) and said second top valve insert (20).

3. The common rail (10) for an engine in accordance with Claim 2 wherein said tapered shank portion (26) comprises a first diameter (28), a second diameter (30), and a tapered portion defined between the first diameter (28) and the second diameter (30), said tapered portion adapted to translate within the bore (24), wherein a diameter of the bore (24) decreases when said tapered shank portion (26) translates from the first diameter (28) to the second diameter (30) to facilitate reducing a cross sectional area of said bore (24).
4. The common rail (10) for an engine in accordance with Claim 3 further comprising a spring member (32) positioned between said sleeve (22) and a bottom portion of said first top valve insert (18) and said second top valve insert (20), said spring member (32) adapted to restore said sleeve (22) after fuel has been supplied through the bore (24).
, Description:Field of the invention
[0001] This invention relates to a common rail for an engine.

Background of the invention
[0002] US 6565013 B describes a common rail injector having an injector housing, which communicates via a fuel inlet with a central high-pressure reservoir, which is supplied with fuel from a fuel tank, which fuel, as a function of the position of a 3/2-way magnet valve, passes into a high-pressure bore of an injection nozzle, and the 3/2-way magnet valve has a control piston, which can be moved back and forth between a closed and an open valve position and which on one of its two ends is coupled with an armature and whose other end projects into a pressureless chamber, and in the open valve position the fuel inlet communicates with the high-pressure bore of the injection nozzle, and in the closed valve position, the fuel inlet is closed by the control piston and the high-pressure bore of the injection nozzle communicates with a fuel outlet and with the pressureless chamber. To optimize the motion of the control piston in the flight phase, a first throttle restriction is disposed between the high-pressure bore and the fuel outlet.

Brief description of the accompanying drawings
[0003] Figure 1 illustrates a common rail for an engine.
[0004] Figure 2 illustrates a sleeve that is disposed in the common rail for the engine.

Detailed description of the embodiments
[0005] Figure 1 illustrates a common rail 10 for an engine. The common rail 10 comprises a fuel storage chamber 12 and a throttle 14 in flow communication with the fuel storage chamber 12. The throttle 14 comprises a bottom valve insert 16, a first top valve insert 18 and a second top valve insert 20. A sleeve 22 is positioned between the bottom valve insert 16 and between the first top valve insert 18 and the second top valve insert 20, the sleeve 22 adapted to translate within the bore 24 defined between the first top valve insert 18 and the second top valve insert 20.

[0006] The common rail 10 for the engine comprises a fuel storage chamber 12. The fuel storage chamber 12 of the common rail 10 is adapted to store pressurized fuel and deliver it to a plurality of fuel injectors via a plurality of throttles 14. Each of the plurality of throttles 14 of the common rail 10 comprises a bottom valve insert 16, a first top valve insert 18 and a second top valve insert 20 that is spaced from the first top valve insert 18 to define a bore 24 there between. A sleeve 22 is positioned between the first top valve insert 18, the second top valve insert 20, and the bottom valve insert 16. The sleeve 22 is positioned with a portion within the bore 24 and translates within the bore 24. More specifically, the sleeve 22 comprises a tapered shank portion 26 that is adapted to translate within the bore 24 defined between the first top valve insert 18 and the second top valve insert 20. The tapered shank portion 26 comprises a first diameter 28, a second diameter 30, and a tapered portion defined between the first diameter 28 and the second diameter 30. The tapered portion is adapted to translate within the bore 24, wherein a diameter of the bore 24 decreases when the tapered shank portion 26 translates from the first diameter 28 to the second diameter 30 to facilitate reducing a cross sectional area of the bore 24. When the first diameter 28 of the tapered portion of the sleeve 22 is adjacent to the bore 24, the diameter of the bore 24 is maximum. As the tapered portion of the sleeve 22 translates and the second diameter 30 of the tapered portion of the sleeve 22 is adjacent to the bore 24, the diameter of the bore 24 is minimum. Therefore, the diameter of the bore 24 gradually decreases from a maximum diameter to a minimum diameter when the tapered portion of the sleeve 22 translates from the first diameter 28 to the second diameter 30.

[0007] In an exemplary embodiment, the sleeve 22 comprises the tapered portion that extends between the first diameter 28 to the second diameter 30. In an alternate exemplary embodiment, the sleeve 22 comprises a flat portion that extends between the first diameter 28 and the second diameter 30. In such an instance, the first diameter 28 is the same as the second diameter 30. In yet an alternate exemplary embodiment, the sleeve 22 comprises any portion that may be shaped according to a user’s requirement and that extends between the first diameter 28 and the second diameter 30 that facilitates channeling fuel within the bore 24 at a variable rate in accordance with the shape of the sleeve 22 that reciprocates within the bore 24.

[0008] The common rail 10 for the engine comprises a spring member 32. The spring member 32 is positioned between the sleeve 22 and a bottom portion of the first top valve insert 18 and the second top valve insert 20. The spring member 32 is adapted to restore the sleeve member 22 to its original position after fuel has been supplied through the bore 24 and injected through the fuel injector.

[0009] A working of the common rail 10 for the engine is described as an example. Fuel flows into the common rail 10 from a high pressure fuel pump. From the common rail 10, the pressurized fuel is supplied to each of the plurality of throttles 14. The pressurized fuel in each of the plurality of throttles 14 applies a compressive force on the sleeve 22 against a force of the spring member 32, thereby causing the sleeve 22 to translate within the bore 24 while at the same time delivering fuel from the common rail 10 to each of the fuel injectors. As the sleeve 22 translates within the bore 24 against the force of the spring member 32, the diameter of the bore 24 decreases due to the tapered portion of the sleeve 22. The reduction in the diameter of the bore 24 causes a reduced quantity of fuel to be delivered out of the common rail 10 to each of the fuel injectors to produce a throttling effect. If the fuel entering each of the plurality of throttles 14 is at a lower pressure, the low pressure fuel fails to exert sufficient pressure on the sleeve 22 thereby causing the sleeve 22 to remain stationary, and causing the bore 24 to continue being enlarged. The enlarged diameter of the bore 24 causes a greater quantity of fuel to be delivered from each of the throttles 14 to each of the fuel injectors. Therefore, depending on the pressure of the fuel that is acting on the sleeve 22, the sleeve 22 may translate by a proportional displacement thereby causing the bore 24 to close and deliver a required mass flow rate of fuel out of the common rail 10 to each of the plurality of injectors. After the common rail 10 has finished delivering pressurized fuel to each of the plurality of fuel injectors, the pressure of fuel acting on the sleeve 22 decreases. Therefore, the spring member 32 that is positioned between the sleeve 22 and a bottom portion of the first top valve insert 18 and the second top valve insert 20 exerts a restoring force on the sleeve 22, thereby causing the sleeve 22 to translate and return to its original position thereby creating the maximum bore diameter due to the restoring force of the spring member 32.

[0010] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to leverage and dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.