CLIAMS:I Claim:

1. A high pressure pump (100) for pumping fluid comprising,

a housing (105) having an axial bore (140) defined therein;

a plunger (110) disposed in said axial bore and adapted to linearly reciprocate within said axial bore ;

said axial bore opens to a feed space (145) in the housing;

an inlet valve assembly (115) disposed in said feed space adapted to supply fluid to said pumping chamber;

a delivery valve assembly (120) disposed in said feed space adapted to deliver high pressure fluid from said pumping chamber,

said high pressure pump characterized in that
said inlet valve is disposed in a direction inclined with the axis of motion of the plunger.

2. A high pressure pump of claim 1, wherein said delivery valve is disposed in a direction inclined with the axis of motion of the plunger.

3. A high pressure pump of claim 1, wherein said inlet valve assembly and said outlet valve assembly are positioned symmetrical about the axis of motion of the plunger.

4. A high pressure pump (200) for pumping fluid comprising,

a housing (205) having an axial bore (240) defined therein;

a plunger(210) disposed in said axial bore and adapted to linearly reciprocate within said axial bore ;

said axial bore opens to a feed space (240) in the housing;

an inlet valve assembly (215) disposed in said feed space adapted to supply fluid to said pumping chamber;

a delivery valve assembly (220) disposed in said feed space adapted to deliver high pressure fluid from said pumping chamber;

said high pressure pump characterized in that
said inlet valve is operated in a direction parallel with the axis of motion of the plunger

5. A high pressure pump of claim 1, wherein said delivery valve is operated in a direction parallel with the axis of motion of the plunger. ,TagSPECI:Field of the invention
[001] This invention relates to a high pressure fluid pump for applications like fuel injection system of internal combustion engines.

Background of the invention
[002] Conventionally, a high pressure pump has a plunger, which is driven by a cam connected to an internal combustion engine. The motion of the plunger of the high pressure pump discharges fuel from a pump chamber. A valve member controls the amount of fuel flowing into the pump chamber through a fuel passage.

[003] According to US-6345608 B1, a high pressure pump has a movable plunger and a movable valve member. The movable axis of the plunger is substantially coaxial with respect to the movable axis of the valve member. According to US-6631706 B1, the movable axis of the plunger is perpendicular to the movable axis of the valve member. When the plunger is coaxial with respect to the valve member, size of the pump may increase in the axial direction of the plunger and this may lead to difficulties during packaging, assembling and mounting of the fuel pump.

[004] When the movable axis of the plunger is perpendicular to the movable axis of the valve member, the flow of fuel to the inlet valve assembly is not aided by gravity. Also the size of the pump will increase due this kind of configuration.

[005] Hence there is a need for a new design of high pressure pump that makes easier for assembling, packaging and mounting of the pump and at the same time making use of the gravitational force during filling of the fluid to the pumping chamber and also with a better fluid flow path inside the pump assembly.

Brief description of the accompanying drawings
[006] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawings:

[007] Figure 1 illustrates an embodiment of the invention where the inlet valve assembly is disposed in a direction inclined with the axis of motion of the plunger.
[008] Figure 2 illustrates an embodiment of the invention where the inlet valve assembly is disposed in a direction parallel with the direction of motion of the plunger.

Detailed description of the embodiments

[009] Figure 1 illustrates a first embodiment of the invention. The device 100 disclosed herein is a modular high pressure pump. The high pressure pump in accordance with the present invention is a high pressure fuel injection pump used for supplying fuel to fuel injection system of an internal combustion engine. The fuel injection system may be the common rail system in a diesel engine or a gasoline engine. The high pressure pump includes housing (105), an inlet valve assembly (115), a delivery valve assembly (120), a plunger (110), a plunger return spring (135) and plunger retainer (130). The housing accommodates an axial bore (140) and at least one bore (125) inclined with the axis of the housing. The axial bore is in flow communication with the inclined bore. The axial bore acts as a pumping chamber for the high pressure pump and inclined bore forms part of the feed space provided to accommodate the valve assembly. An inlet valve assembly is accommodated in one of the inclined bores provided in the housing. The axial bore accommodates the plunger (110) which reciprocates inside it. Each of the inclined bores provided in the housing along with the top part of the axial bore defines a feed space (145) in the housing. The axial bores provided in the housing are positioned in a direction inclined with the axis of motion of the plunger.
[0010] In another embodiment, the inlet valve is operated at an angle with a first axis parallel to the axis of motion of the plunger, wherein said first axis is displaced from the axis of motion of the plunger and said angle is in the range of 0 to 180 degrees.

[0011] In one of the embodiment, the inlet valve is oriented in a direction with an inclination with the axis of motion of the plunger such that the use of gravitational force for enhancing the flow rate while filling the fluid in to pump is utilised.

[0012] The inlet valve opens when the pressure in the high pressure pump goes below the inlet valve opening pressure thereby allowing the fuel into the pumping chamber. The fluid entered through the inlet valve assembly accommodated in one of the inclined bore of the housing, flows towards the pumping chamber. Due to reciprocating motion of the plunger, the pressure of the fluid in the feed space increases. The delivery valve opens when the pressure in the high pressure Pump chamber is above the fluid supply line and delivers the fuel to the fluid supply line. The fluid supply line can be the common rail in a fuel injection system of an IC engine. Thus the pressurized fluid flows out of the fuel pump to the fuel injection system.

[0013] In another embodiment of the invention, two inclined bores are accommodated inside the housing. One for accommodating the inlet valve assembly and the other for accommodating the delivery valve assembly and each of these inclined bores is accommodated on both sides of the axis of the pump. In an alternate embodiment, the two inclined bores are symmetrical about the axis of motion of the plunger.

[0014] When the inlet valve assembly is operated in an inclined direction with the direction of motion of the plunger, the flow of fluid is aided by gravity and at the same time achieving a space saving design of the pump.

[0015] Figure 2 illustrates a second embodiment of the invention. The device 200 disclosed herein is a modular high pressure pump. The high pressure pump is a high pressure fuel injection pump used for supplying fuel to fuel injection system of an internal combustion engine. The fuel injection system can be the common rail system in a diesel engine or a gasoline engine. The high pressure pump includes housing (205), an inlet valve assembly (215), a delivery valve assembly (220), a plunger (210), a plunger return spring (235) and plunger retainer (230). The housing accommodates an axial bore (240). The axial bore acts as a pumping chamber for the high pressure pump and opens to a feed space (245) in the housing. The axial bore accommodates a plunger (210) which reciprocates inside it. Two valve assemblies, an inlet valve assembly (215) and a delivery valve assembly (220), are accommodated in the feed space. The inlet valve assembly is operated in a direction parallel with the direction of motion of plunger.

[0016] In an alternate embodiment of the invention, the outlet valve assembly is operated in a direction parallel with the direction of motion of the plunger.

[0017] The inlet valve opens when the pressure in the high pressure pump goes below the inlet valve opening pressure thereby allowing the fuel into the high pressure pump. The fluid entered through the inlet valve assembly flow towards the pumping chamber. Due to reciprocating motion of the plunger, the pressure of the fluid in the feed space increases.. The delivery valve opens when the pressure in the High pressure Pump is above the rail pressure and delivers the fuel to the rail. Thus the pressurized fluid flows out of the fuel pump to the fuel injection system.

[0018] In all the embodiments mentioned above, optimal positions of the valve assemblies for achieving the space saving of the high pressure pump design and at the same time for using the effect of gravity while filling the fluid to the pump assembly. Also the embodiment, where the inlet valve assembly and outlet valve assembly are accommodated in an inclined direction symmetrical about the axis of motion of the plunger, is providing a better fluid flow path inside the high pressure pump assembly. All the embodiments mentioned above is describing a modular design of the high pressure pump. The modular manner of constructing the pump units enable high pressure pumps to be realized without any problems and in a space saving manner. Also it is possible for said pumps to be adapted in the best possible manner to the requirements present in each case as a function of the particular combination of modules. For example, based on the flow and pressure requirements, the different valve configurations can be used in the inlet and outlet valve assemblies.

[0019] 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.