Claims:1. A high pressure fuel pump (10), said high pressure fuel pump (10) comprising:
10 a housing (12);
a plunger (14) positioned within the barrel positioned in said housing (12), said
plunger (14) adapted to reciprocate within the barrel positioned in said housing
(12);
a stop groove (16) defined in said plunger (14), said stop groove (16) adapted
15 to extend along a sidewall of said plunger (14);
a helix groove (18) in flow communication with the stop groove (16) and
extending angularly along a sidewall of said plunger (14); characterized in that
a rectangular shaped groove (20) positioned between the helix groove (18) and
a top portion of said plunger (14), the rectangular shaped groove (20) adapted
20 to prevent pressurization and delivery of fuel from said high pressure fuel
pump (10) to a fuel injector at low pumping speeds of said high pressure fuel
pump (10).
2. The high pressure fuel pump (10) in accordance with Claim 1, wherein a major
25 axis of the rectangular shaped groove (20) is perpendicular to a longitudinal
axis of said plunger (14).
3. The high pressure fuel pump (10) in accordance with Claim 2, wherein a
portion of said plunger (14) between the rectangular shaped groove (20) and a
30 top portion of said plunger (14) has an area of cross section that is greater than
an area of cross section of the rectangular shaped groove (20), and wherein the
portion of said plunger (14) between the rectangular shaped groove (20) and the top portion of said plunger (14) constitutes an effective stroke 5 of said high
pressure fuel pump (10).
4. The high pressure fuel pump (10) in accordance with Claim 1, wherein a length
of the rectangular shaped groove (20) is defined by a user, and a breadth of the
10 rectangular shaped groove (20) is defined by the user for a user specific
application.
5. The high pressure fuel pump (10) in accordance with Claim 1, wherein a major
axis of the rectangular shaped groove (20) is parallel to a longitudinal axis of
15 said plunger (14).
6. The high pressure fuel pump (10) in accordance with Claim 2, wherein the
rectangular shaped groove (20) extends between the top portion of said helix
groove (18) and a top portion of said plunger (14) of said high pressure fuel
20 pump (10).
7. The high pressure fuel pump (10) in accordance with Claim 1, wherein a
length of the rectangular shaped groove (20) is defined by a user, and a breadth
of the rectangular shaped groove (20) is defined by the user for a user specific
25 application. , Description:A high pressure fuel pump 10 is described. The high pressure fuel pump 10 comprises
a housing 12, and a plunger 14 positioned within the housing 12. The plunger 14 is
adapted to reciprocate within the barrel positioned in the housing 12. A stop groove
10 16 is defined in the plunger 14, the stop groove 16 adapted to extend along a sidewall
of the plunger 14. A helix groove 18 is in flow communication with the stop groove
16 and extends angularly along a sidewall of the plunger 14. A rectangular shaped
groove 20 is positioned between the helix groove 18 and a top portion of the plunger
14, the rectangular shaped groove 20 adapted to prevent pressurization and delivery of
15 fuel from the high pressure fuel pump 10 to a fuel injector at low pumping speeds of
the high pressure fuel pump 10.