CLIAMS:1 A fuel pump comprising:
a pumping chamber (105) comprising an inlet (110) and an outlet (115), a plunger mounted in said pumping chamber (105) and is adapted to pump fuel from said inlet (110) to said outlet (115);
characterized in that
said pumping chamber (105) comprising a conical cavity (120) at said outlet (115) and adapted to accommodate a valve member (125) for preventing and enabling fluid communication between said pumping chamber (105) and a high pressure line.

2 The fuel pump as claimed in claim 1, wherein radius of curvature of said conical cavity (120) is larger than radius of said valve member (125).

3 The fuel pump as claimed in claim 1, wherein said valve member (125) is a ball.
,TagSPECI:Field of the invention
[001] This invention relates to a fuel pump.

Background of the invention
[002] A delivery valve assembly including a plurality of components enables delivery of high pressure fuel from a pumping chamber, of a fuel pump, to a high pressure line. The delivery valve assembly also performs function of preventing draining of the fuel from the high pressure line back into the pumping chamber.

[003] Conventionally, the delivery valve assembly includes a valve body, a valve member, a spring and a valve holder. The valve body is located at outlet of the pumping chamber and accommodates the valve member.

[004] When the fuel in the pumping chamber is pressurized, the valve member is adapted to open a delivery conduit through which the fuel is delivered to the high pressure line. The valve body defines a valve seat that enables the valve member to remain in a closed position for preventing fluid communication between the high pressure line and the pumping chamber after the delivery of the fuel, thereby preventing draining of the fuel from the high pressure line back into the pumping chamber. Hence, the valve member acts as a check valve. However, existing delivery valve assembly includes multiple components that are required to be assembled along the delivery conduit for performing these functions.

[005] Hence, there is still a need to minimize number of components to achieve the above mentioned functions.

Brief description of the accompanying drawings

[006] Figure 1 illustrates a fuel pump, in accordance with one embodiment

Detailed description
[007] Figure 1 illustrates a fuel pump, in accordance with one embodiment. The fuel pump comprises a pumping chamber 105 that has an inlet 110 and an outlet 115. The pumping chamber 105 is characterized by a conical cavity 120 at the outlet 115. The conical cavity 120 is adapted to accommodate a valve member 125 for preventing and enabling fluid communication between said pumping chamber 105 and a high pressure line.

[008] The fuel pump comprises a pump housing that houses the pumping chamber 105. Low pressure fuel, from a fuel tank, is supplied into the pumping chamber 105 through the inlet 110.

[009] The plunger mounted in the pumping chamber 105 is adapted to reciprocate between a bottom end of the pumping chamber 105 to a top end of the pumping chamber 105. Such reciprocatory movement of the plunger is obtained using a cam and a cam shaft. Movement of the plunger from the bottom end to the top end of the pumping chamber 105 pressurizes the fuel present within the pumping chamber 105. The top end of the pumping chamber 105 is proximal to the outlet 115 and pressurized fuel is delivered to the high pressure line through the outlet 115 along a delivery conduit.

[0010] The pumping chamber 105 is characterized by a conical cavity 120 at the outlet 115. The conical cavity 120 is adapted to accommodate a valve member 125. In one example, the valve member is a ball.

[0011] The conical cavity 120 is centered at axis of the pumping chamber 105. The conical cavity 120 may be obtained by subjecting the pumping chamber 105 to a machining operation. Radius of curvature of the conical cavity 120 is larger than the radius of the valve member 125 so that the conical cavity 120 can accommodate the valve member 125.

[0012] When the conical cavity 120 accommodates the valve member 125 a line contact is established between the pumping chamber 105 and the valve member 125. Such line contact is lost during the delivery of the fuel, as the valve member 125 may move such that it disengages itself from the conical cavity 120. After the delivery of the fuel the line contact between the pumping chamber 105 and the valve member 125 is re-established as the valve member 125 moves such that it gets engaged within the conical cavity 120. Such movement of the valve member 125, during the delivery of the fuel and after the delivery of the fuel, is explained in detail in the below paragraphs.

[0013] The high pressure fuel within the pumping chamber 105 upon reaching the outlet 115 is incident on the valve member 125 since the outlet 115 is provided with the conical cavity 120 that accommodates the valve member 125. When the high pressure fuel is incident on the valve member 125, the valve member 125 moves and disengages itself from the conical cavity 120. The valve member 125 disengages itself from the conical cavity 120 when force exerted by the high pressure fuel on the valve member 125 is sufficient such that the valve member 125 moves overcoming a spring force of a spring 130 that is located in the delivery conduit.

[0014] When the valve member 125 is disengages, the line contact existing between the pumping chamber 105 and the valve member 125 is lost, thereby creating a fluid communication between the pumping chamber 105 and the high pressure line. The high pressure fuel thus flows into the high pressure line through the outlet 115 of the pumping chamber 105 along the delivery conduit.

[0015] Upon delivery, the pressure of the fuel drops and the valve member 125 moves such that it accommodates itself within the conical cavity 120 thereby re-establishing the line contact between the pumping chamber 105 and the valve member 125. Re-establishment of the line contact prevents fluid communication between the pumping chamber 105 and the high pressure line thereby preventing draining of the fuel from the high pressure line back into the pumping chamber 105.

[0016] A pumping chamber characterized by a conical cavity at the outlet eliminates need for using and assembling a separate element such as a valve holder, to accommodate the valve member. Therefore the fuel pump characterized by pumping chamber defining a conical cavity at the outlet is cost effective.

[0017] 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 type of fuel pump, shape of the cavity, type of the valve member are envisaged and form a part of this invention. The scope of the invention is only limited by the claims.