Claims:WE CLAIM:

1. A high pressure pump assembly (10) for use in engines, the pump assembly (10) comprising:
a high pressure pump (105) for pumping fuel received from a fuel tank (110);
a return line (115) connected to the high pressure pump to enable fuel return to the fuel tank (110);
characterized in that:
an activated charcoal capsule (120) disposed in the return line (115).
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] This invention relates to a high pressure pump assembly.

Background of the invention
[0002] High pressure fuel pumps are used for pressurizing fuel before pumping to the engine cylinders. The fuel pumps also have a return line to return excess fuel back to the fuel tank. The plunger and the barrel assembly in the pump is lubricated by engine oil. Therefore, there will be a mixing of oil in the fuel that is pressurized by the pump. This produces discoloration of the fuel that is returned to the fuel tank and discolors the fuel in the tank as well. Therefore, there is a need to filter or clean the discolored fuel.

Brief description of the accompanying drawing
[0003] Figure 1 shows a schematic of a high pressure pump assembly; and

[0004] Figure 2 shows a schematic of an activated charcoal capsule.

Detailed description of the embodiments
[0005] Figure 1 shows a schematic of a high pressure pump assembly 10. The high pressure pump assembly 10 comprises a high pressure pump 105 for pumping fuel received from a fuel tank 110. The pressurized fuel is pumped to the common rail in a common rail based engine or to the injector, which is understood by a person of ordinary skill in the art. The high pressure pump assembly 10 further comprises a return line 115 which is to return the excess fuel back to the fuel tank 110. The return line 115 comprises an activated charcoal capsule 120.
[0006] Figure 2 shows a schematic of the activated charcoal capsule 120. In an exemplary arrangement, the diameter of the return line 115 is ?8mm. Hence, the diameter of the capsule 120 is within 8mm and marginally less than ?8mm, such that the capsule 120 fits snugly in the return line 115. The surface area of the activated carbon in the charcoal is 500 to 1500 m2/g. The packing density of the activated charcoal is 0.3 – 0.6 g/ml. The pH value is 4.0 ~ 4.8. The optimum temperature for working of the activated charcoal is 60°C ~ 70°C.

[0007] Activated charcoal has an intrinsic pore network in the lattice structure which allows removal of impurities through the mechanism of adsorption. Adsorption is the attachment or adhesion of atoms, ions and molecules from the fuel medium onto the surface of the adsorbent. These molecules of oil that need to be filtered out are then trapped with the carbon’s internal pore structure by Van der Waals forces or other bonds of attraction and accumulate onto the solid surface.

[0008] This helps remove the oil from the returning fuel in the return line 115. Once the oil is removed, the discoloration of the fuel is also reduced. The advantage of this arrangement is that, the effects of engine oil mixing with fuel or diesel is reduced and that filtered or purified fuel returns to the fuel tank 110. The additional advantage is that any soot in the fuel can also be filtered by the capsule 120 such that any clogging of the fuel filter is reduced.

[0009] This arrangement can be used in a single cylinder oil lubricated pump system and in general is applicable to any engine where a high pressure pump is used and a return line is attached to the pump. This arrangement can be used with both diesel and gasoline.

[0010] 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.