Claims:We Claim:
1. A fuel metering unit (10) for use with a common rail pump (20), comprising:
a stem (105) adapted to be inserted into a slot (205) in the common rail pump (10);
characterized in that:
a biased projection (110) disposed on the stem (105) and adapted to fit into a recess (210) in the slot (205) in the common rail pump (20).

2. The fuel metering unit (10) as claimed in claim 1, further comprising:
another biased projection (115) disposed on the stem (105) and diametrically opposite the biased projection (110), the another biased projection (115) adapted to fit into another recess (215) in the slot (205).

3. The fuel metering unit (10) as claimed in claim 2, wherein the biased projection (110) and the another biased projection (115) are disposed at an end (117) of the stem (105), the end (117) distal from a main body (118) of the fuel metering unit (10), the main body (118) of the fuel metering unit (10) located outside of the slot (205).

4. The fuel metering unit (10) as claimed in claim 1, further comprising:
at least one groove (120) disposed circumferentially on the stem (105), the at least one groove (120) adapted to support a sealing ring with the slot (205) in the common rail pump (20).

5. The fuel metering unit (10) as claimed in claim 4, wherein the at least one groove (120) comprises three grooves (120, 125, 130) disposed along a length of the stem (105), each of the three grooves (120, 125, 130) adapted to support a sealing ring with the slot (205) in the common rail pump (20).

6. A common rail pump (20) for receiving a fuel metering unit (10), comprising:
a slot (205) adapted to receive a stem (105) of the fuel metering unit (10);
characterized in that:
a recess (210) disposed in the slot (205) and adapted to receive a biased projection (110) disposed on the stem (105) of the fuel metering unit (10).

7. The common rail pump (20) as claimed in claim 6, further comprising:
another recess (215) disposed in the slot (205) and diametrically opposite the recess (210), the another recess (215) adapted to receive another biased projection (115) disposed on the stem (105) of the fuel metering unit (10).

8. A fuel control unit for receiving a fuel metering unit (10), comprising:
a slot (205) adapted to receive a stem (105) of the fuel metering unit (10);
characterized in that:
a recess (210) disposed in the slot (205) and adapted to receive a biased projection (110) disposed on the stem (105) of the fuel metering unit (10). , Description:FIELD OF THE INVENTION
[0001] This invention relates to a fuel metering unit and a common rail pump for receiving the fuel metering unit.

BACKGROUND OF THE INVENTION
[0002] Fuel metering units are mounted onto common rail pumps or the fuel control units. This is done by inserting the stem of the fuel metering unit into the slot of the common rail pump or the fuel control unit and fitting the metering unit in place. Once fitted in place, the fuel metering unit is fixed by suitable fasteners such as screws etc.

BRIEF DESCRIPTION OF DRAWINGS
[0003] An embodiment of this disclosure is explained in principle below with reference to the drawings. The drawings are:
[0004] FIGURE 1 illustrates a first arrangement of a fuel metering unit and a common rail pump;
[0005] FIGURE 2 illustrates a second arrangement of the fuel metering unit and the common rail pump; and
[0006] FIGURE 3 illustrates a third arrangement of the fuel metering unit and the common rail pump.

DETAILED DESCRIPTION
[0007] FIGURE 1 illustrates a first arrangement of a fuel metering unit 10 and a common rail pump 20. The fuel metering unit 10 for use with the common rail pump 20 comprises a stem 105 adapted to be inserted into a slot 205 in the common rail pump 20. The fuel metering unit further comprises a biased projection 110 disposed on the stem 105 of the fuel metering unit 10 and adapted to fit into a recess 210 in the slot 205 in the common rail pump 20.
[0008] FIGURE 2 illustrates a second arrangement of the fuel metering unit 10 and the common rail pump 20. The second arrangement of the fuel metering unit 10 and the common rail pump 20 comprises two biased projections on the stem 105 of the fuel metering unit 10. According to the second arrangement, the fuel metering unit 10 further comprises another biased projection 115 disposed on the stem 105 and diametrically opposite the biased projection 110. The another biased projection 115 is adapted to fit into another recess 215 in the slot 205. The biased projection 110 and the another biased projection 115 can be biased by a spring or any similar resilient member.
[0009] Furthermore, the biased projection 110 and the another biased projection 115 are disposed at an end 117 of the stem 105, the end 117 distal from a main body 118 of the fuel metering unit 10, the main body 118 of the fuel metering unit 10 located outside of the slot 205. The functionality and working of the biased projections will be described hereinafter.
[00010] FIGURE 3 illustrates a third arrangement of the fuel metering unit 10 and the common rail pump 20. The fuel metering unit 10 comprises at least one groove disposed circumferentially on the stem 105, the at least one groove adapted to support a sealing ring (not shown in FIGURES) with the slot 205 in the common rail pump 20. In other words, by way of the groove disposed circumferentially on the stem 105, the groove encircles the circumference of the stem 105. As illustrated in FIGURE 3, the at least one groove comprises three grooves 120, 125 and 130 disposed along the length of the stem 105, each of the three grooves 120, 125 and 130 adapted to support a sealing ring with the slot 205 in the common rail pump 20. The functionality and the working of the grooves will be explained hereinafter.
[00011] As illustrated in FIGURE 1, the common rail pump 20 for receiving the fuel metering unit 10 comprises the slot 205 adapted to receive the stem 105 of the fuel metering unit 10. The common rail pump 20 further comprises the recess 210 disposed in the slot 205 and adapted to receive the biased projection 110 disposed on the stem 105 of the fuel metering unit 10. As illustrated in FIGURE 2, the common rail pump 20 further comprises another recess 215 disposed in the slot 205 and diametrically opposite the recess 210, wherein the another recess 215 is adapted to receive another biased projection 115 disposed on the stem 105 of the fuel metering unit 10.

[00012] As illustrated in FIGURE 1 and FIGURE 2, the biased projection 110 and the another biased projection 115 enables locking and securing the fuel metering unit 10 in place. The spring or the resilient member in the biased projection 110 and the another biased projection 115 enables the projection to be pressed or pushed towards the stem 105 when the fuel metering unit 10 is inserted into the slot 205 of the common rail pump 20. Once the biased projection 110 and the another biased projection 115 are fully surrounded by the recess 210 and the another recess 215, the stored energy of the resilient member or the spring member pushes the projections 110 and 115 into the recesses 210 and 215 respectively and securely locks them. In case of the first arrangement illustrated in FIGURE 1, only the biased projection 110 is securely locked inside the recess 210. The advantage of this locking enables securing the fuel metering unit 10 with the common rail pump 20.
[00013] Each of the grooves 120, 125 and 130 are adapted to support a sealing ring with the slot 205 of the common rail pump 20. The sealing ring can be an O-ring or similar. In other words, when the fuel metering unit 10 is fitted into the common rail pump 20, the sealing rings are disposed and squeezed between the grooves 120, 125 and 130 and the slot 205 of the common rail pump 20. The sealing rings, by virtue of their placement between the grooves and the slot 205 provide a force which facilitates holding the fuel metering unit 10 securely in place. The advantage provided by the grooves is that they enable placement of the sealing rings between themselves and the slot 205, such that the fuel metering unit 10 is secured inside the slot 205 of the common rail pump 20. The advantage of having at least one biased projection fitting into the recess of the slot 205 and the clamping by the sealing rings in the grooves provides an improved holding force between the fuel metering unit 10 and the common rail pump 20.
[00014] Similar to the common rail pump 20, a fuel control unit can also receive the fuel metering unit 10. The fuel control unit comprises a slot 205 adapted to receive a stem 105 of the fuel metering unit 10. The fuel control unit comprises a recess 210 disposed in the slot 205 and adapted to receive a biased projection 110 disposed on the stem 105 of the fuel metering unit 10. The fuel control unit comprises all features explained with reference to the common rail pump 20 earlier and functions in the same way as well.
[00015] It is to be understood that the foregoing description is intended to be purely illustrative of the principles of the disclosed techniques, rather than exhaustive thereof, and that changes and variations will be apparent to those skilled in the art, and that the present invention is not intended to be limited other than as expressly set forth in the following claims.