Fuel supply apparatus and method of control thereof
AssigneeHitachi, Ltd.
InventorsKenichiro Tokuo, Kenji Hiraku, Tadahiko Nogami, Kunihiko Takao, Hiroyuki Yamada
Life of this patent
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Abstract
In a fuel supply apparatus disclosed, a variable displacement mechanism is driven once every two or more reciprocating motions of the plunger of a high-pressure fuel pump to control the delivery flow rate, so that the delivery flow rate control can be performed without having to raise the responsiveness of the variable displacement mechanism even when the reciprocating cycle of the plunger is short.
Claims14
A fuel supply apparatus comprising:
- a fuel pump having a pump chamber, a pump plunger reciprocating in the pump chamber, a suction valve connected to a suction side of the pump chamber, a delivery valve connected to a delivery side of the pump chamber, and an actuator opening and closing the suction valve;
- and
- a controller regulating, through control of the actuator, a pressure of fuel to be supplied to an injector that is substantially constant, said controller controlling the actuator to open the suction valve only once and close the suction valve only once during at least two reciprocating motions of the plunger, thereby varying a delivery flow rate of the fuel pump.
A fuel supply apparatus comprising:
- a fuel pump having a pump chamber, a pump plunger reciprocating in the pump chamber, a suction valve connected to a suction side of the pump chamber, a delivery valve connected to a delivery side of the pump chamber, and an actuator opening and closing the suction valve;
- and
- a controller regulating, through control of the actuator, a pressure of fuel to be supplied to an injector that is substantially constant, the controller controlling timing of closing of the suction valve in a delivery stroke of one of two reciprocating motions of the plunger, and keeping one of opening of the suction valve and closing of the suction valve in a delivery stroke of the other reciprocating motion to effect no control on a delivery flow rate of the fuel pump, thereby varying the flow rate of fuel delivered from the fuel pump in two delivery strokes.
A method of controlling a fuel supply apparatus including a fuel pump having a pump chamber, a pump plunger reciprocating in the pump chamber, a suction valve connected to a suction side of the pump chamber, a delivery valve connected to a delivery side of the pump chamber, and an actuator opening and closing the suction valve, the method comprising controlling of the actuator to open the suction valve only once and closing the suction valve only once during at least two reciprocating motions of the plunger, thereby varying a delivery flow rate of the fuel pump.
A method of controlling a fuel supply apparatus including a fuel pump having a pump chamber, a pump plunger reciprocating in the pump chamber, a suction valve connected to a suction side of the pump chamber, a delivery valve connected to a delivery side of the pump chamber, and an actuator opening and closing the suction valve, the method comprising calculating a necessary fuel supply rate to the injector, such that (i) when the fuel supply rate is at 50% or less of a maximum delivery flow rate of the fuel pump, in one of two reciprocating motions of the plunger, the suction valve is kept open to prevent delivery of fuel and, in the other reciprocating motion, controlling timing of closing of the suction valve to control the delivery flow rate of the fuel pump, and (ii) when the fuel supply rate is at 50% or more of the maximum delivery flow rate of the fuel pump, in one of two reciprocating motions of the plunger, controlling timing of closing of the suction valve and, in a delivery stroke of the other reciprocating motion, holding the actuator to close the suction valve to control the delivery flow rate of the fuel pump.
Dependencies are inferred from the claim text.