Fuel injection pump
AssigneeDiesel Kiki Co., Ltd.
InventorMasayoshi Kobayashi
Life of this patent
Estimating the term…
Abstract
A distributor type fuel injection pump which includes a relief passage having one end thereof opening in the pump working chamber and the other end communicating with a zone under a lower pressure. Said relief passage is so arranged as to be permanently kept closed by a valve means which is actuated by a valve actuating means for actuating said valve means in response to a fuel supply pressure varying as a function of the engine rotational speed, except in a predetermined low engine speed range, to obtain a decreased injection rate during idling so as to increase the injection period. Thus, the rate of combustion of the engine is reduced to minimize the combustion noise.
Claims2
In a fuel injection pump for an internal combustion engine, including:
- a housing, a barrel mounted within said housing;
- a plunger mounted within said barrel for axial and rotary motion therein;
- a pump working chamber defined by the housing, the barrel and the plunger;
- a suction chamber formed within said housing;
- and outlet pressure lines for connecting said pump working chamber with associated fuel injection nozzles;
- the improvement which comprises:
- a relief passage having one end thereof opening in said pump working chamber and the other end communicating with a zone under a lower pressure, said relief passage extending from said barrel through said housing;
- a valve means arranged for blocking said relief passage;
- and
- an actuating means for actuating said valve means in response to a fuel supply pressure varying as a function of engine rotational speed, said actuating means being arranged to actuate said valve means to permanently keep said relief passage closed except in a predetermined low engine speed range;
- said valve means comprising a bore formed within said pump housing and communicating on one side with said relief passage and on the other side with a zone under a lower pressure;
- a piston slidably received with said bore, said piston including an annular groove formed in an outer periphery thereof, and a restriction passage having one end thereof radially opening in said annular groove and the other end communicating with said lower pressure zone;
- and
- said actuating means comprising a passage means having one end thereof communicating with one end of said bore and the other end thereof with a fuel pump arranged for rotation at a speed which is a function of the rotational speed of the engine;
- said pressure means comprising a fuel supply line having two ends, one end of said fuel supply line communicating with said suction chamber formed within said pump housing, which is supplied with a fuel pressure which is a function of the engine speed from said fuel pump, and the other end of said fuel supply line being arranged for communication with said pump working chamber;
- a further annular groove formed around an outer periphery of said barrel and intersecting with said fuel supply line;
- and a communicating port formed within said housing and providing communication between said further annular groove and said bore.
Dependencies are inferred from the claim text.