Claims:We claim:
1. A delivery valve (100) for a fuel injection pump, comprising a channel (104) for the passage of fuel and a valve member (108) with an opening (114), said valve member (108) located in between an outlet path (112) of said pump and an inlet of said channel (104), characterized in that,
a spacer (106) having a profile comprising a cavity (202) within a wall (206) to accommodate said valve member (108) and at least one recess (204) in an inner surface of said wall (206) forming a flow path around a periphery of said valve member (108).

2. The delivery valve (100) as claimed in claim 1, wherein said spacer (106) fluidly couples said outlet path (112) of said pump to inlet of said channel (104).

3. The delivery valve (100) as claimed in claim 1, wherein said valve member (108) is movable towards said cavity (202) to enable fuel flow through said flow path and through said opening (114) of said valve member (108) into said channel (104) during delivery of fuel.

4. The delivery valve (100) as claimed in claim 1, wherein said opening (114) is narrower than said outlet path (112) and said inlet, which dampens a pressure of said fuel during back flow.

5. The delivery valve (100) as claimed in claim 1, wherein a height of said valve member (108) is any one of lesser than, equal to, and more than height of said wall (206).

6. A delivery valve (100) for a fuel injection pump, comprising a channel (104) for the passage of fuel and a valve member (108) with an opening (114), said valve member (108) located in between an outlet path (112) of said pump and an inlet of said channel (104), characterized in that,
said inlet having a profile comprising a cavity (202) within a wall (206) to accommodate a valve member (108) and at least one recess (204) in an inner surface of said wall (206) forming a flow path around a periphery of said valve member (108).

7. The delivery valve (100) as claimed in claim 6, wherein said spacer (106) fluidly couples said outlet path (112) of said pump to inlet of said channel (104).

8. The delivery valve (100) as claimed in claim 6, wherein said valve member (108) is movable towards said cavity (202) to enable fuel flow through said flow path and through said opening (114) of said valve member (108) into said channel (104) during delivery of fuel.

9. The delivery valve (100) as claimed in claim 6, wherein said opening (114) is narrower than said outlet path (112) and said inlet, which dampens a pressure of said fuel during back flow.

10. The delivery valve (100) as claimed in claim 6, wherein a height of said valve member (108) is any one of lesser than, equal to, and more than height of said wall (206).

, Description:Field of the invention:
[0001] The present invention relates to a delivery valve for a fuel injection pump, and particularly relates to a simplified delivery valve assembly.

Background of the invention:
[0002] A Fuel Injection Pump (FIP) involves delivering the quantified pressurized fuel at the right instance. Pump principally consists of element/plunger, delivery valve (DV). The plunger constricts the fuel by the act of reciprocation. A delivery valve holder consists of a valve pin and valve body whose function is to deliver fuel to the high pressure line during forward stroke and throttle, which dampens secondary pressure wave.
[0003] In existing delivery valve holder designs, the delivery valve assembly is housed in the delivery valve holder. The valve pin lifts during pressurization and allows for fuel to be delivered to high pressure line. Above the delivery valve chamber, a throttle plate is housed inside the delivery valve holder to restrict the secondary pressure waves in the high pressure system. The design of delivery valve consists of various components, which results in high dead volume inside the delivery valve chamber. This leads to a constraint in achieving higher injection pressure required to meet higher emission standards.
[0004] According to a patent literature EP0061534, a delivery valve for a fuel injection pump is disclosed. The delivery valve is installed between an injection pump and an injection valve and has a disc-like valve body which is pressed against a valve seat by a closing spring and which forms a throttle cross-section with a channel. The dimensions of the valve body, the throttle cross-section and the closing force of the closing spring are matched to one another in such a manner that after an injection process has finished, the valve body moves with delay in the direction of the valve seat. This prevents a hard reflection of the pressure wave which would lead to the injection valve opening again.
[0005] Hence, there is a need for an improved delivery valve for the fuel injection pumps.

Brief description of the accompanying drawings:
[0006] An embodiment of the disclosure is described with reference to the following accompanying drawing,
[0007] Fig. 1 illustrates a cut-section view of a delivery valve for a fuel injection pump, according to an embodiment of the present invention, and
[0008] Fig. 2 illustrates a spacer in different views, according to an embodiment of the present invention.

Detailed description of the embodiments:
[0009] Fig. 1 illustrates a cut-section view of a delivery valve for a fuel injection pump, according to an embodiment of the present invention. The delivery valve 100 for a fuel injection pump (not shown) is provided, comprising a channel 104 in a valve body 102 for the passage of fuel and a valve member 108 with an opening 114. The valve member 108 is located in between an outlet path 112 of the pump and an inlet of the channel 104. The outlet path 112 is provided in a valve holder 110 section of the pump to which the delivery valve 100 is mounted or connected. The delivery valve 100 is characterized by a spacer 106 having a profile comprising a cavity 202 (shown in Fig. 2) within a wall 206 (shown in Fig. 2) to accommodate the valve member 108. The spacer 106 also comprises at least one recess 204 in an inner surface of the wall 206 forming a flow path around a periphery of the valve member 108. The opening 114 is at least one through hole in the valve member 108.
[0010] The valve member 108 is either completely within the spacer 106, or is partially out of the spacer 106. A compartment may or may not be formed between the valve holder 110 and the spacer 106. The Fig. 1 shows the valve member 108 with height greater than the wall 206 inside the compartment.
[0011] A working of the delivery valve 100 before and after fuel delivery is described. The upward movement of the valve member 108 takes place when the fuel in the pump is pressurized, such as pressurization from a plunger (not shown) in a pump chamber (not shown). Before the fuel is pressurized, the valve member 108 either rests on the valve holder 110 or the spacer 106 based on the orientation of the pump. Considering the orientation in which the valve member 108 rests on the valve holder 110, then there is a surface contact between valve member 108 and the valve holder 110. As the plunger advances, the pressure in the pump chamber increases. The pressurized fuel reaches the spacer 106 through the outlet path 112. The valve member 108 is pushed against the cavity 202 of the spacer 106. The pressurized fuel flows through the flow path around the periphery of the valve member 108. Then, the fuel is delivered through the channel 104 of the delivery valve 100. The arrows in the channel 104 and the outlet path 112 illustrates direction of fuel flow.
[0012] At the end of delivery stroke, when the pressure in the pump chamber drops, the valve member 108 moves away from the spacer 106 and rests on the valve holder 110. However, at the end of delivery stroke, a secondary pressure wave from the end of the channel 104 travels towards the fuel injection pump. The valve member 108 acts as a throttle during this phenomenon. The fuel passes through the opening 114 of the valve member 108, and helps in dampening the effects of return pressure wave.
[0013] Fig. 2 illustrates a spacer in different views, according to an embodiment of the present invention. The illustration 210 shows a cut-section view of the spacer 106. The cavity 202 is shown with a base to restrict the movement of the valve member 108. The spacer 106 fluidly couples the outlet path 112 of the pump to the inlet of the channel 104.
[0014] The illustration 220 shown top view of the spacer 106. Three recesses 204 are shown but the same must not be understood in a limiting manner, as less or more number of recesses 204 can be provided.
[0015] The illustration 230 shows the top view of the spacer 106 with the valve member 108 positioned inside the cavity 202. The arrows in the recesses 204 shows the direction of fuel flow during delivery stroke. The valve member 108 is movable towards the cavity 202 to enable fuel flow through the flow path and through the opening 114 of the valve member 108. The fuel flows through the flow path into the channel 104 during delivery of fuel. The opening 114 is narrower than the outlet path 112 and the inlet, which aids in dampening a pressure of the fuel during back flow. The height of the valve member 108 is any one of lesser than, equal to, and more than height of the wall 206.
[0016] In accordance to an embodiment of the present invention, a delivery valve 100 for a fuel injection pump is provided, comprising a channel 104 for the passage of the fuel and a valve member 108 with an opening 114. The valve member 108 is located in between the outlet path 112 of the valve holder 110 part of the pump and the inlet of the channel 104. The delivery valve 100 is characterized by the inlet having a profile comprising a cavity 202 within a wall 206 to accommodate the valve member 108, and at least one recess 204 in an inner surface of the wall 206 forming a flow path around the periphery of the valve member 108. The design of the delivery valve 100 itself is made like the spacer 106. Thus the valve member 108 is located inside the delivery valve 100 without the spacer 100 but having a design of the spacer 100. The internal design of the delivery valve is similar to as explained in Fig. 2.
[0017] The spacer 106 fluidly couples the outlet path 112 of the pump to inlet of said channel 104. The valve member 108 is movable towards the cavity 202 to enable fuel flow through the flow path and through the opening 114 of the valve member 108 into the channel 104 during delivery of fuel.
[0018] The opening 114 is narrower than the outlet path 112 and the inlet of the channel 104, which dampens a pressure of the fuel during back flow. The height of the valve member 108 is any one of lesser than, equal to, and more than the height of the wall 206.
[0019] In accordance to an embodiment of the present invention, a simplified design of the delivery valve 100 for the fuel injection pump is disclosed. The secondary pressure waves are dampened by the valve member 108. The delivery valve 100 comprises less dead volume resulting in higher injection pressure. The process of assembly of the delivery valve 100 and the fuel injection pump is simplified. Due to less number of components, the manufacturing cost of the delivery valve 100 is reduced. The weight of the fuel injection pump is also reduced. The present invention discloses an assembly with integrated delivery valve 100 and throttle function thereby retaining the dampening function of return pressure waves. Also discloses a simplified delivery valve 100 with reduced dead volume resulting in high injection pressures.
[0020] Higher injection pressures require the system to have reduced dead volumes. The reduction is dead volume is achieved by integration of delivery valve 100 and throttle function into a single component. The dead volume in delivery valve 100 is drastically reduced as compared to previous design resulting in increased injection pressures.
[0021] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.