JP4478944B2 - Fluid metering valve and fuel injection pump using the same - Google Patents

Description

  The present invention relates to a fluid metering valve for metering a fluid flow rate and a fuel injection pump using the fluid metering valve.

  As a fluid metering valve for metering the flow rate of fluid flowing in from a fluid inlet and flowing out from a fluid outlet, one using a solenoid valve as used in a fuel injection pump is known (for example, Patent Document 1). 2, 3). In these fuel injection pumps, a fluid metering valve is provided on the fuel inlet side of the fuel pressurizing chamber, and the fluid metering valve is opened and closed to intermittently connect the fuel pressurizing chamber and the fuel inlet. Then, by controlling energization of the electromagnetic drive unit, the valve closing timing of the fluid metering valve at the time of fuel pressurization is controlled to adjust the fuel discharge amount.

Japanese Patent Publication No. 50-6043 JP-A-10-141177 JP 2002-48033 A

  However, in the fluid metering valves of Patent Literatures 1, 2, and 3, the fluid metering valve is closed by energizing the electromagnetic drive unit and moving the movable member with a magnetic attraction force. Keep the valve open. In such a configuration in which the movable member that is separated from the suction side via the gap is attracted and moved by magnetic force, a large magnetic attraction force is required to attract the movable member. As a result, there is a problem that the electromagnetic drive unit becomes large or the power consumption for generating the magnetic attractive force increases. Further, in the configuration in which the movable member is sucked through the gap, the passage area when the fluid metering valve is opened is increased in order to increase the responsiveness of sucking and moving the movable member after energizing the electromagnetic drive unit. In order to increase the gap to increase, it is necessary to increase the magnetic attractive force. As a result, there is a problem that the electromagnetic drive unit becomes large or the power consumption for generating the magnetic attractive force increases.

  The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a fluid metering valve that reduces the power consumption by reducing the size of the electromagnetic drive unit.

According to the first to third aspects of the invention, by generating a magnetic attractive force between the valve member and the stopper, it is moved to the downstream side by the differential pressure between the upstream side and the downstream side and is locked to the stopper. Since the valve member is held at the valve open position, the valve member can be held at the valve open position with a small magnetic attractive force. Thereby, an electromagnetic drive part can be reduced in size and power consumption can be reduced. When the energization to the electromagnetic drive unit is turned off, the valve member reciprocates due to the differential pressure between the upstream side and the downstream side, and the valve member interrupts communication between the fluid inlet side and the fluid outlet side.

In addition, since a magnetic attraction force is applied between the valve member and the stopper while the valve member is locked to the stopper, even if the lift amount of the valve member is increased to increase the fluid inflow amount from the fluid inlet, There is no need to increase the suction power.
In addition, the valve member of the metering valve moves in the valve opening direction and the valve closing direction due to a change in the differential pressure, not in the magnetic attraction force. The responsiveness is improved as compared with the movement of the valve member in the direction or the valve closing direction.

In the second aspect of the invention, fuel flows between the valve member side and the plunger side through the fluid passage formed in the stopper. Therefore, the fuel can be sucked into the fluid chamber by the lowering of the plunger, and the fuel in the fluid chamber pressurized by the lift of the plunger can be discharged from the fluid outlet.
According to the third aspect of the present invention, even when the valve member is locked to the stopper, the fuel passes through the fluid passage formed around the contact portion between the valve member and the stopper, and fuel is supplied to the fluid chamber as the plunger descends. Inhalable.

A plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
A fuel injection pump according to a first embodiment of the present invention is shown in FIG. The fuel injection pump 10 measures the discharge amount of high-pressure fuel by a metering valve 20 that is a fluid metering valve, and is, for example, a high-pressure supply pump that supplies fuel to an injector of a diesel engine or a gasoline engine.

The plunger 12 is supported by the housing 22 so as to be reciprocally movable, and reciprocates together with the tappet 14. The tappet 14 is pressed toward the cam 2 by the urging force of the spring 16, and the outer bottom surface of the tappet 14 slides with the cam 2 as the cam 2 rotates.
The housing 22 serves as the housing of the metering valve 20 and the cylinder that forms the fuel pressurizing chamber 200. A fuel pressurizing chamber 200, a fuel inlet 210, and a fuel outlet 212 are formed in the housing 22. The “fluid chamber”, “fluid inlet”, and “fluid outlet” recited in the claims correspond to the fuel pressurizing chamber 200, the fuel inlet 210, and the fuel outlet 212, respectively.

  The metering valve 20 includes a housing 22, a stopper 30, a valve member 40, a spring 42 as an urging member, and a coil 50 as an electromagnetic drive unit. The stopper 30, the valve member 40 and the spring 42 are installed in the fuel pressurizing chamber 200. The stopper 30 is provided on the fuel downstream side of the valve member 40. For example, the stopper 30 is formed in a plate shape by coating the surface of a magnetic material with a nonmagnetic material. As shown in FIG. 1B, four notches are formed on the outer periphery of the stopper 30. By this notch, a fuel passage 202 that is a fluid passage is formed between the stopper 30 and the inner peripheral surface of the housing 22.

The valve member 40 and the spring 42 are installed on the opposite side of the plunger 12 with respect to the stopper 30 together with the fuel inlet 210 and the fuel outlet 212. The valve member 40 is formed in a cup shape, for example, by coating the surface of a magnetic material or a magnetic material with a nonmagnetic material. The valve member 40 is urged toward the valve seat 23 provided on the fuel inlet 210 side of the housing 22 by the urging force of the spring 42. When the valve member 40 is seated on the valve seat 23, the fuel inlet 210 is closed. When energization of the coil 50 is turned on, a magnetic attractive force acts between the valve member 40 and the stopper 30. Energization of the coil 50 is controlled by an electronic control unit (ECU) 70.
The fuel discharge valve 60 is installed at the fuel outlet 212. When the pressure in the fuel pressurizing chamber 200 becomes equal to or higher than a predetermined pressure, the ball 62 separates from the valve seat 66 against the biasing force of the spring 64, and the fuel in the fuel pressurizing chamber 200 is discharged from the fuel outlet 212.

Next, the operation of the fuel injection pump 10 will be described with reference to FIGS. 1 and 2.
(1) Suction Step As shown in FIGS. 2A and 2B, as the cam 2 rotates, the plunger 12 descends from the top dead center toward the bottom dead center, and the pressure in the fuel pressurizing chamber 200 is reduced. When the pressure decreases, the differential pressure received by the valve member 40 from the fuel inlet 210 side which is the upstream side of the valve member 40 and the fuel pressurization chamber 200 which is the downstream side changes. The sum of the force received in the direction in which the valve member 40 is seated on the valve seat 23 by the fuel pressure in the fuel pressurizing chamber 200 and the urging force of the spring 42 is calculated by the fuel pressure on the fuel inlet 210 side. When the force is less than the force received in the direction away from the valve seat 23, the valve member 40 moves away from the valve seat 23 and is locked by the stopper 30. As a result, fuel is sucked into the fuel pressurizing chamber 200 from the fuel inlet 210. Even in the state shown in FIG. 2B where the valve member 40 is locked to the stopper 30, the fuel passage 202 is formed around the joint between the valve member 40 and the stopper 30. The fuel is sucked into the plunger 12 side of the fuel pressurizing chamber 200 through 202.

  The ECU 70 determines from the rotation angle signal of the cam 2 that the valve member 40 is locked to the stopper 30 before the plunger 12 reaches the bottom dead center, and the stopper 30 and the valve member 40 are in contact with each other. Energization is turned on (Ts in FIG. 2). Since the stopper 30 and the valve member 40 are in contact with each other, the magnetic attraction force required to maintain the valve open state in which the valve member 40 is locked to the stopper 30 may be small.

(2) Returning step As shown in FIG. 2C, when the plunger 12 is lifted from the bottom dead center toward the top dead center, the fuel in the fuel pressurizing chamber 200 on the valve member 40 side through the fuel passage 202. Since the pressure rises, the force that the valve member 40 receives toward the valve seat 23 increases. However, energization of the coil 50 is in an on state, and a magnetic attractive force is acting between the stopper 30 and the valve member 40. Therefore, the valve member 40 is held in the valve-opened position locked to the stopper 30. Is done. As a result, the open state of the fuel inlet 210 is maintained, so that the fuel in the fuel pressurizing chamber 200 pressurized by the lift of the plunger 12 flows out from the fuel inlet 210 to the low pressure side.

(3) Pressure feeding process When the energization to the coil 50 is turned off during the returning process (Te in FIG. 2), the magnetic attractive force does not work between the valve member 40 and the stopper 30. As a result, the sum of the force that the valve member 40 receives in the direction in which the valve member 40 is seated on the valve seat 23 due to the fuel pressure in the fuel pressurizing chamber 200 and the biasing force of the spring 42 is Since the force is greater than the force received in the direction away from the seat 23, the valve member 40 is seated on the valve seat 23 by the differential pressure, and the fuel inlet 210 is closed. When the plunger 12 is further lifted toward the top dead center in this state, the fuel in the fuel pressurizing chamber 200 is pressurized and the fuel pressure rises. When the fuel pressure in the fuel pressurizing chamber 200 exceeds a predetermined pressure, the ball 62 separates from the valve seat 66 against the biasing force of the spring 64, and the fuel discharge valve 60 is opened. As a result, the fuel pressurized in the fuel pressurizing chamber 200 is discharged from the fuel outlet 212.
Then, fuel is discharged from the fuel injection pump 10 by repeating the steps (1), (2), and (3).

In FIG. 2, the timing Ts at which the coil 50 is turned on may be any timing as long as it is between T1 when the plunger 12 reaches top dead center and T2 during the suction process.
By the way, since the magnetic attractive force acting between the stopper 30 and the valve member 40 is small, for example, the energization to the coil 50 is turned on at the timing T1 where the valve member 40 is seated on the valve seat 23 on the fuel inlet 210 side. However, the valve member 40 does not move toward the downstream stopper 30 by the magnetic attractive force, but moves downstream by the differential pressure and is locked to the stopper 30.

  Timing T2 considers a response delay until the magnetic attractive force acts between the valve member 40 and the stopper 30 after turning on the coil 50, and the plunger 12 moves from the bottom dead center to the top dead center. Even when the valve is lifted, it is the latest timing at which the valve opening state where the valve member 40 is locked to the stopper 30 can be maintained.

FIGS. 3 and 4 are examples in which the fuel discharge amount is adjusted by changing the timing at which the coil 50 is energized from on to off. The timing Ts for turning on the coil 50 from OFF to ON is the same as in FIG.
In FIG. 3, the energization to the coil 50 is turned off at the timing Te1 before the plunger 12 reaches the bottom dead center earlier than the timing Te at which the energization to the coil 50 is turned off in FIG. When the plunger 12 starts to lift from the bottom dead center to the top dead center, the fuel inlet 210 is immediately closed and the pumping process is started. In this case, the fuel discharge amount is maximized. Even if the power supply to the coil 50 is kept off, the fuel inlet 210 is opened and closed as in FIG. 3, and the fuel discharge amount is maximized.

On the other hand, in FIG. 4, the energization to the coil 50 is turned off at a timing Te2 later than the timing Te to deenergize the coil 50 in FIG. 2, so that the return process becomes longer and the pumping process becomes shorter. Accordingly, the fuel discharge amount is smaller than that in FIG.
Thus, the fuel discharge amount is adjusted by controlling the energization timing to the coil 50 and the metering valve 20 opening and closing the fuel inlet 210.

(Second, third and fourth embodiments)
FIG. 5 shows a second embodiment of the present invention, FIG. 6 shows a third embodiment, and FIG. 7 shows a fourth embodiment. In addition, the same code | symbol is attached | subjected to the substantially same component as 1st Embodiment, and description is abbreviate | omitted.
The fuel injection pumps of the second, third, and fourth embodiments are different from the fuel injection pump 10 of the first embodiment in the configuration of the metering valve.

In the fuel injection pump 80 of the second embodiment shown in FIG. 5, the stopper 84 and the valve member 86 of the metering valve 82 have protrusions that protrude toward each other, and these protrusions Abut.
In the fuel injection pump 90 of the third embodiment shown in FIG. 6, the valve member 94 of the metering valve 92 is formed in a cup shape, and has a flange 96 that spreads outward on the opening side facing the stopper 30. . Thereby, since the area of the valve member 94 latched by the stopper 30 increases, the valve member 94 is prevented from being tilted while being latched by the stopper 30.
In the fuel injection pump 100 according to the fourth embodiment shown in FIG. 7, a recess for locking the spring 42 is formed on the stopper 104 of the metering valve 102. The ball 106 and the cylinder member 108 constitute a valve member.

  In the plurality of embodiments described above, a valve opening position locked to the stopper by applying a magnetic attractive force between the stopper and the valve member that is locked to the stopper on the downstream side by the differential pressure and in contact with the stopper. Therefore, the valve member can be held at the valve open position with a small magnetic attraction force. As a result, the coil 50 which is an electromagnetic drive part can be reduced in size and the power consumption of the coil 50 can be reduced.

Further, since the magnetic attraction force acts between the valve member and the stopper while the valve member is locked to the stopper, even if the lift amount of the valve member is increased and the fuel intake amount from the fuel inlet 210 is increased, There is no need to increase the magnetic attractive force.
Further, the valve member of the metering valve moves in the valve opening direction and the valve closing direction due to a change in the differential pressure, not in the magnetic attraction force. Or responsiveness improves rather than a valve member moving to a valve closing direction.

(Other embodiments)
In the above embodiments, the stopper is notched to form the fuel passage 202, but the fuel passage may be formed on the inner peripheral surface side of the housing 22.
In the above embodiments, the fluid metering valve of the present invention is applied as a metering valve for metering the fuel discharge amount of the fuel injection pump. However, in addition to the fuel injection pump, the fluid metering valve flows from the fuel inlet and from the fuel outlet. The fluid metering valve of the present invention may be used for any application as long as the flow rate of the flowing fluid is adjusted.

(A) is sectional drawing which shows the fuel supply apparatus by 1st Embodiment of this invention, (B) is the figure which looked at the stopper from the plunger side. It is explanatory drawing which shows the relationship between plunger lift, opening and closing of a fuel inlet, and electricity supply to a coil. It is another explanatory drawing which shows the relationship between plunger lift, opening and closing of a fuel inlet, and electricity supply to a coil. It is another explanatory drawing which shows the relationship between plunger lift, opening and closing of a fuel inlet, and electricity supply to a coil. It is sectional drawing which shows the fuel supply apparatus by 2nd Embodiment of this invention. It is sectional drawing which shows the fuel supply apparatus by 3rd Embodiment of this invention. It is sectional drawing which shows the fuel supply apparatus by 4th Embodiment of this invention.

Explanation of symbols

10, 80, 90, 100 Fuel supply device, 20, 82, 92, 102 Metering valve (fluid metering valve), 22 Housing, 30, 84, 104 Stopper, 40, 86, 94 Valve member, 42 Spring, 50 Coil (electromagnetic drive unit), 60 fuel discharge valve, 70 ECU (electronic control unit), 106 ball (valve member), 108 cylinder member (valve member), 200 fuel pressurization chamber (fluid chamber), 202 fuel passage (fluid) Passage), 210 fuel inlet (fluid inlet), 212 fuel outlet (fluid outlet)

Claims (3)

In the fluid metering valve for metering the fluid flow rate flowing in from the fluid inlet and flowing out from the fluid outlet,
A valve member installed in a fluid chamber formed between the fluid inlet and the fluid outlet, and reciprocates according to a differential pressure between the upstream side and the downstream side of the valve member, A valve member for communicating the fluid inlet and the fluid outlet by moving;
A stopper provided on the downstream side of the valve member for locking the valve member;
And an electromagnetic drive unit that generates a magnetic attractive force between the valve member and the stopper by energization, and holds the valve member in a valve-opening position locked to the stopper by a differential pressure,
A fluid metering valve for metering the flow rate of fluid flowing in from the fluid inlet and flowing out from the fluid outlet;
A plunger that pressurizes fuel flowing into the fluid chamber from the fluid inlet by reciprocating and discharges the fuel from the fluid outlet;
With
The fuel injection pump, wherein the fluid inlet, the fluid outlet, and the valve member are formed on a side opposite to the plunger with respect to the stopper. Fuel injection pump according to claim 1, wherein the fluid passage is formed in the stopper. The fuel injection pump according to claim 1 or 2 , wherein a fluid passage is formed around a contact portion between the valve member and the stopper.

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