Variable-discharge high pressure pump
AssigneeNippondenso Co., Ltd.
InventorsShigeyuki Kondo, Yoshihisa Yamamoto
Life of this patent
Estimating the term…
Abstract
A variable-discharge high pressure pump for pressure-feeding fuel to a common rail for use in a diesel engine. The pump has a plunger, a plunger chamber, a cam for reciprocatively moving the plunger; and opening-out type electromagnetic valve capable of opening and closing one end of the plunger chamber, a fuel reservoir, a check valve communicating with the plunger chamber, and an inlet pipe for supplying fuel to the fuel reservoir. Both the introduction of the fuel into the plunger chamber and the return of the fuel from the plunger chamber to the fuel reservoir are effected through the electromagnetic valve.
Claims11
A variable-discharge high pressure pump for pressurizing and pressure-feeding fuel to a common rail of a diesel engine, said pump comprising:
- a plunger;
- a plunger chamber in which said plunger is movably accommodated;
- a cam for reciprocally moving said plunger;
- an electromagnetic valve capable of opening out to the interior of said plunger chamber;
- a fuel reservoir communicating with said plunger chamber through said electromagnetic valve;
- a check valve communicating with said plunger chamber and capable of opening at a predetermined pressure;
- and
- an inlet pipe for supplying a low pressure fuel to said fuel reservoir;
- wherein said plunger chamber and said inlet pipe communicate with each other through said fuel reservoir and said electromagnetic valve, and both the introduction of the low pressure fuel into said plunger chamber and the return of the low pressure fuel from said plunger chamber to said fuel reservoir are effected through said electromagnetic valve;
- and
- wherein a discharge of fuel from said plunger chamber into said common rail is finished when a forward stroking motion of the plunger is finished.
A method of controlling a variable-discharge high pressure pump for pressurizing and pressure-feeding fuel to a common rail of a diesel engine, the pump having:
- a plunger;
- a plunger chamber in which the plunger is movably accommodated;
- a cam for reciprocatively moving the plunger;
- an electromagnetic valve capable of opening out to the interior of the plunger chamber;
- a fuel reservoir communicating with the plunger chamber through the electromagnetic valve;
- a check valve communicating with the plunger chamber and capable of opening at a predetermined pressure;
- and an inlet pipe for supplying a low pressure fuel to the fuel reservoir;
- said method comprising the steps of:
- effecting both the introduction of the low pressure fuel into the plunger chamber and the return of the low pressure fuel from the plunger chamber to the fuel reservoir mainly through the electromagnetic valve;
- controlling the fuel pressure in the common rail by energizing and de-energizing the electromagnetic valve;
- and
- finishing discharge of fuel from the plunger chamber into the common rail when a forward stroking movement of the plunger is finished.
Dependencies are inferred from the claim text.