Claims:1. A high pressure fuel pump (10), said high pressure fuel pump (10) comprising:
10 a housing (12), and a plunger (14) adapted to reciprocate within a pumping
chamber defined within said housing (12);
a helix groove (16) defined on an outer circumference of said plunger (14), the
helix groove (16) adapted to channel pressurized fuel from within the pumping
chamber defined within said housing (12) to a fuel gallery (20) during an end
15 of a pumping stroke of said plunger (14);
a stop groove (18) defined at an end of the helix groove (16), the stop groove
(18) adapted to channel pressurized fuel from within the pumping chamber
defined within said housing (12) to said fuel gallery (20) during a stop
condition of said high pressure fuel pump (10), and wherein said plunger (14)
20 is adapted to be rotated to facilitate varying an orientation of the helix groove
(16) and the stop groove (18) for different loading conditions of said high
pressure fuel pump (10);
a barrel (22) positioned between said plunger (14) and said housing (12), said
barrel (22) comprising:
25 an inlet port (24) extending from an inner surface of said barrel (22) to
an outer surface of said barrel (22) and in flow communication with
said fuel gallery (20), the inlet port (24) adapted to channel pressurized
fuel from the helix groove (16) defined on the outer circumference of
said plunger (14) to said fuel gallery (20) during the end of the pumping
30 stroke of said plunger (14); characterized in that
a leak oil port (26) extending from the inner surface of said barrel (22)
to the outer surface of said barrel (22), an axis of the leak oil port (26)
positioned at a user defined angle with reference to an 5 axis of the inlet
port (24) such that when said plunger (14) is rotated by a predetermined
angular displacement, the stop groove (18) defined at the end of the
helix groove (16) of said plunger (14) is aligned with the leak oil port
(26) to facilitate discharging pressurized fuel from within the pumping
10 chamber defined within said housing 12 to said fuel gallery (20) via the
stop groove (18) and via the leak oil port (26).
2. The high pressure fuel pump (10) in accordance with Claim 1 wherein the axis
of the leak oil port (26) is positioned at a user defined angle between 150
15 degrees and 160 degrees with reference to the axis of the inlet port (24) such
that when said plunger (14) is rotated at the user defined angle between 150
degrees and 160 degrees with reference to the axis of the inlet port (24), the
stop groove (18) defined at the end of the helix groove (16) of said plunger
(14) is aligned with the leak oil port (26) to facilitate discharging pressurized
20 fuel from within the pumping chamber defined within said housing (12) to said
fuel gallery (20) via the stop groove (18) and via the leak oil port (26).
3. The high pressure fuel pump (10) in accordance with Claim 1 wherein the axis
of the leak oil port (26) is positioned at a user defined angle of 155 degrees
25 with reference to the axis of the inlet port (24) such that when said plunger (14)
is rotated at the user defined angle of 155 degrees with reference to the axis of
the inlet port (24), the stop groove (18) defined at the end of the helix groove
(16) of said plunger (14) is aligned with the leak oil port (26) to facilitate
discharging pressurized fuel from within the pumping chamber defined within
30 said housing (12) to said fuel gallery (20) via the stop groove (18) and via the
leak oil port (26).
4. The high pressure fuel pump (10) in accordance with Claim 5 1 wherein said
plunger (14) is rotated by the predetermined angular displacement to facilitate
rotating the helix groove (16) defined in the plunger (14) such that the helix
groove (16) is at a farthest displacement with reference to the inlet port (24)
that extends through said barrel (22) of said high pressure fuel pump (10).
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5. The high pressure fuel pump (10) in accordance with Claim 4 wherein said
plunger (14) is rotated by the predetermined angular displacement by means of
a control rod that is secured to said plunger (14) by means of a rack and pinion
gear arrangement.
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6. The high pressure fuel pump (10) in accordance with Claim 5 wherein said
plunger (14) is rotated by the predetermined angular displacement by means of
said control rod when a governor that is secured to said control rod fails. , Description:A high pressure fuel pump 10 is described. The high pressure fuel pump 10 comprises
a housing 12, and a plunger 14 adapted to reciprocate within the housing 12. A helix
groove 16 is defined on an outer circumference of the plunger 14. A stop groove 18 is
10 defined at an end of the helix groove 16. A barrel 22 is positioned between the plunger
14 and the housing 12. A leak oil port 26 extends through the barrel 22, an axis of the
leak oil port 26 positioned at a user defined angle with reference to an axis of an inlet
port 24 such that when the plunger 14 is rotated by a predetermined angular
displacement, the stop groove 18 is aligned with the leak oil port 26 to facilitate
15 discharging pressurized fuel from within the pumping chamber to the fuel gallery 20
via the leak oil port 26.