CLIAMS:We Claim:

1. A fuel injection pump 100, said fuel injection pump 100 comprising

a housing 105;
a suction valve 101 comprising a suction valve bore 106;
an outlet valve 102 comprising an outlet valve bore 107;

said housing 105 comprising said suction valve 101 in fluid communication with an inlet port and said outlet valve 102, and said outlet valve 102 in fluid communication with said suction valve 101 and an outlet port;

characterized in that

a key 103 held in a slot positioned on a surface of said suction valve 101 and said outlet valve 102, said key 103 aligns said suction valve bore 106 with said outlet valve bore 107.

2. The fuel injection pump 100 as claimed in claim 1, wherein a delivery valve holder 104 provides a path for fuel flow from said outlet valve 102 to a high pressure pipe. ,TagSPECI:FIELD OF THE INVENTION

[001] The invention relates to a fuel injection pump. More particularly, it relates to aligning a suction valve with an outlet valve using a key.

BACKGROUND OF THE INVENTION

[002] Fuel injection pump supplies fuel into the cylinders of an engine. The fuel injection pump comprises a plunger, a suction valve, a discharge valve and housing. The discharge valve of the fuel injection pump is connected to the high-pressure delivery pipe. Dowel pins are used to align the suction valve bore and the outlet valve bore in the housing of the fuel injection pump. A clamping nut is used to secure the position of the aligned suction valve and the discharge valve in the housing during the working of the fuel injection pump. A pre-load is applied and the clamping nut is screwed onto the housing. The pre-load is applied to avoid misalignment of the suction valve and the discharge valve while tightening the clamping nut onto the housing.

[003] US patent 7350505, discloses a common rail fuel pump for an internal combustion engine includes a pumping plunger that reciprocates within a plunger bore provided in pump housing under the influence of a drive arrangement to cause fuel pressurisation within a pump chamber. An inlet metering valve meters the quantity of fuel supplied to the pump chamber during the return stroke of the plunger. An outlet valve controls the supply of pressurised fuel from the pumping chamber through an outlet passage to the common rail fuel volume when the inlet metering valve is closed. The inlet metering valve, the plunger and the pump outlet are arranged in axial alignment.

SHORT DESCRIPTION OF THE DRAWING

[004] An exemplifying embodiment of the invention is explained in principle below with reference to the drawings. The drawings are,

[005] Figure 1 illustrates a fuel injection pump in accordance with this invention.

DESCRIPTION OF THE INVENTION

[006] Figure 1 illustrates a fuel injection pump 100 in accordance with this invention. The fuel injection pump 100 comprises a housing 105; a suction valve 101 comprising a suction valve bore 106; an outlet valve 102 comprising an outlet valve bore 107; the housing 105 comprising the suction valve 101 in fluid communication with an inlet port and the outlet valve 102, and the outlet valve 102 in fluid communication with the suction valve 101 and an outlet port; characterized in that a key 103 held in a slot positioned on a surface of the suction valve 101 and the outlet valve 102, the key 103 aligns the suction valve bore 106 with the outlet valve bore 107.

[007] During the intake stroke of the engine, the fuel flows from the inlet port to the suction valve 101. When the fuel is pressurized due to the movement of the piston and the plunger, the fuel flows from the plunger bore via the suction valve bore 106, the outlet valve bore 107 and a delivery valve holder 104 to a high pressure pipe. To align the suction valve 101 with the outlet valve 102, the slot is provided on the surface of the suction valve 101 and the outlet valve 102 to receive the key 103. While assembling the suction valve 101 and the outlet valve 102 onto the housing 105, the slot guides the key 103 such that the key 103 locks the suction valve 101 with the outlet valve 102 and aligns the suction valve bore 106 with the outlet valve bore 107. Thus the suction valve bore 106 and the outlet valve bore 107 are aligned for the flow of fuel. The use of the key 103 in the fuel injection pump 100 enables easy assembly of the suction valve 101 and the outlet valve 102 into the housing 105 of the fuel injection pump 100. The use of the key 103 eliminates the use of the dowel pins for aligning the suction valve 101 with the outlet valve 102.

[008] During the working of the fuel injection pump 100, a delivery valve holder 104 secures the position of the suction valve 101 and the outlet valve 102 in the housing 105 of the fuel injection pump 100. The delivery valve holder 104 comprises external threads and is fastened to the housing 105 comprising internal threads. The delivery valve holder 104 provides a path for fuel flow from the outlet valve 102 to the high pressure pipe. The use of the delivery valve holder 104 eliminates the use of a preload to avoid rotation of the assembled suction valve 101 and outlet valve 102 while tightening the delivery valve holder 104 to the housing 105. The key 103 is capable of withstanding the shear load during the tightening of the delivery valve holder 104 to the housing 105, thus avoiding the use of a pre load.

[009] It must be understood that the embodiments explained in the above detailed description in only illustrative and does not limit the scope of this invention. The scope of this invention is limited only by the scope of the claims. Many modification and changes in the embodiments aforementioned are envisaged and are within the scope of this invention.