JPS59185865A - Fuel supply valve - Google Patents

Abstract

PURPOSE:To perform supply and stop of a high pressure fuel with minor force in good response by furnishing the arrangement with a No.1 oil pressure chamber, No.2 oil pressure chamber, oil-hydraulic opening/closing valve, electrical opening/closing valve, etc. CONSTITUTION:As both a solenoid valve 51 and a needle valve 52 are closed before operation, No.1 oil pressure chamber 524 is out of communication with a drain port 502, and an output port 528 is shut. If current is supplied to a solenoid valve 511 at the starting time of injection, the valve element 512 will rise to cause communication between No.1 oil pressure chamber 524 and drain port 502, so that the fuel in No.1 oil pressure chamber 524 be relieved. Because a needle valve 522 is equipped with a throttle 527, the pressure in No.2 oil pressure chamber 525 increases much higher than that in No.1 oil pressure chamber 524 following said relief of the fuel from No.1 oil pressure chamber 524, so that the needle 522 shifts upward. Then the output port 528 is opened, and the fuel is sprayed out of this port to serve as an injection nozzle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply valve, and is effective for use in, for example, a fuel control system for a diesel engine.

Conventionally, in high-pressure fuel supply devices, since high pressure is applied to the valve body, a very large force is required to supply or stop the high-pressure fuel, resulting in poor responsiveness.

In view of the above-mentioned problems, the present invention aims to supply and stop high-pressure fuel with a small force and with good response.

In order to achieve this objective, the present invention has taken the following measures. In other words, a first hydraulic chamber having a drain boat and a second hydraulic chamber having an input boat and an output port are provided, communication between the first hydraulic chamber and the drain boat is opened and closed by an electric on-off valve, and the second hydraulic chamber has a drain boat. Communication between the chamber and the output port is opened and closed by a hydraulic opening/closing valve operated by a pressure difference between the first hydraulic chamber and the second hydraulic chamber.

A first embodiment in which the present invention is applied to a fuel control system for a diesel engine will be described below.

FIG. 1 is a schematic overall view of the first embodiment.

High pressure pump 1 has a normal rated discharge pressure of 250 kg/cnT.
Using a gear pump, fuel is sucked up from the fuel pump 2 and high-pressure fuel is discharged from the discharge port. The high-pressure fuel discharged from the high-pressure pump 1 is passed through a relief valve 3 and 2 for relieving fuel that has reached a pressure of 250 kir/cJ or more.
The fuel is supplied to the input boat 501 of the fuel supply valve 5 via the accumulator 4 for accumulating high pressure fuel of 50 kg/c+a.

The fuel supply valve 5 is a solenoid valve 51 as an electric on-off valve.
and a needle valve 52 as a hydraulic opening/closing valve. The needle valve 52 includes a cylinder 521, a needle 522, and a first spring 523. The needles 522 slide inside the cylinder 521 in the vertical direction in FIG.
24, a second hydraulic chamber 525 is provided. Second hydraulic chamber 52
5 is the input port 501 of the fuel supply valve 5 and the fuel supply passage 5
26 and is provided with an output port 528 for injecting the fuel in the second hydraulic chamber 525. This output port 528 plays the role of an injection nozzle. Further, the needle 522 is also in communication with the first hydraulic chamber 524 via a throttle 527 provided at the center shaft portion. First hydraulic chamber 5
The first spring 523 is disposed within the needle 24, and the spring force of the first spring 523 presses the needle 522 downward. When the hydraulic pressure in the second hydraulic chamber 525 is sufficiently larger than the hydraulic pressure in the first hydraulic chamber 524, the needle 522 moves upward in FIG. 1 against the first spring 523 and is blocked by the needle 522. The output port 528 at the tip of the cylinder opens, and high-pressure fuel is injected into the combustion chamber of the engine (not shown). The first hydraulic chamber 524 communicates with a drain boat 502, which in turn communicates with the fuel tank 2. However, the first hydraulic chamber 524 and the drain boat 502
The communication is opened and closed by the solenoid valve 51.

The solenoid valve 51 includes a solenoid 511, a valve body 512, and a second spring 513, and the valve body 512 is biased by the second spring 513 in a direction to close communication between the first hydraulic chamber 524 and the drain boat 5020. When the solenoid 511 is energized, the electromagnetic force causes the valve body 5 to
12 opens communication between the first hydraulic chamber 524 and the drain boat 502 against the spring force of the second spring 5134. Then, the pressure in the first hydraulic chamber 524 increases to the second hydraulic chamber 52.
As a result, the needle 522 moves in the direction of opening the output port 528 against the spring force of the first spring 523. When the output port 528 opens, high-pressure fuel sent from the high-pressure pump 1 is injected into the combustion chamber (not shown) of the diesel engine from the output port 528, which serves as an injection nozzle. When the solenoid 511 is de-energized, the valve body 512
Communication between the first hydraulic chamber 524 and the drain boat 502 is closed by the force of the spring 513. And the first hydraulic chamber 5
The fuel in the second hydraulic chamber 525 flows into the second hydraulic chamber 525 through the throttle 527 of the needle 522, and the pressure in the first hydraulic chamber 524 and the pressure in the second hydraulic chamber 525 become equal. It is pushed down by the force of the spring 523 to close the output capo 52B and stop fuel injection. The solenoid 511 is energized by the computer 6 via the lead wire 61.

The drive shaft 11 of the high-pressure pump 1 is driven synchronously at 1/2 rotation of an engine (not shown). The drive shaft 11 of the high-pressure pump has a gear 12 with teeth 121 arranged at 5° intervals in order to detect the phase of the engine.
is fixed, and a protrusion 122 that serves as a reference position is provided on the side surface of the gear 12. A first magnetoresistive element (MRE) sensor 1 is mounted opposite the teeth 121 of the gear 12.
31 is provided, and a second MRE sensor 132 is provided opposite the protrusion 122, the first MRE sensor 131 detects a phase signal, and the m2 MRE sensor 132 detects a reference signal and sends it to the computer 6. . A potentiometer 141 is provided on the accelerator 14 to detect an arcel opening signal and send it to the computer 6.

The computer determines the optimum fuel injection start magnetism and injection period according to the engine rotational speed and accelerator opening degree from the above signal, and energizes the fuel supply valve 5 through the lead wire 61 to inject fuel.

Next, the operation of this embodiment will be explained based on FIGS. 2, 3, and 4.

Before operation, both the solenoid valve 51 and the needle valve 52 are closed, so communication between the first hydraulic chamber 524 and the drain boat 502 is cut off, and the output boat 528 is closed.

When the solenoid 511 of the solenoid valve 51 is energized at the start of injection, the magnetic force of the solenoid 511 causes the valve body 512 to rise against the force of the spring 513, as shown in FIG. Since the boat 502 is communicated with, the fuel in the first hydraulic chamber 524 is relieved.

Since the needle 522 is provided with a diaphragm 527, the first
When the fuel in the hydraulic chamber 524 is relieved, the second hydraulic chamber 5
25 becomes significantly larger than the pressure in the first hydraulic chamber 524, the needle 522 moves upward in FIG. 3 against the force of the first spring 523, as shown in FIG. Then, the fuel heard by the output boat 528 and supplied from the high-pressure pump 1 is injected from the output boat 528, which serves as an injection nozzle.

When the energization to the solenoid 511 is stopped, the valve body 512 is lowered by the force of the second spring 513, as shown in FIG. 4, and the solenoid valve 51 is closed. When the solenoid valve 51 closes, the throttle 527 of the needle 522 is placed in the first hydraulic chamber 524.
Since the second hydraulic chamber 525 is filled with fuel via the first
The pressures in the hydraulic chamber 524 and the second hydraulic chamber 525 become equal.

Then, the needle 522 is lowered by the first spring 523, blocking the output boat 528 and stopping fuel injection.

Next, a method of energizing the solenoid 511 will be explained based on FIG. 5.

In FIG. 5, the second MRE sensor 132 is connected to the protrusion 122.
Let A be the reference signal detected by the first MRE sensor 131 from the teeth 12 of the gear 121, B be the phase signal detected by the first MRE sensor 131 from the teeth 12 of the gear 121, be 0 the energization signal to the solenoid 511, and D be the one dollar lift amount. The computer 6 determines the magnetism θ1 to start energizing the solenoid 511 and the magnetism θ4 to end the energization from the reference signal A1 phase signal B and the signal from the potentiometer 141 provided on the accelerator 14, and then controls the solenoid 511 through the lead wire 61.
energize. Note that the actual injection start timing when the needle 522 opens in the engine is θ2 because there is a response delay in the fuel control valve 5, and the actual injection end is θ6. Energization to the solenoid 511 is started and stopped early in anticipation of this response delay.

Next, a second embodiment of the present invention will be described.

In the first embodiment, the output boat itself of the fuel supply valve 5 is used as the injection nozzle, but the injection nozzle 7 may be configured separately from the fuel supply valve 5 as shown in FIG.

That is, the output boat 528 of the second hydraulic chamber 525 and the injection nozzle 7 are communicated through the high pressure line 712, and communication between the second hydraulic chamber 525 and the injection nozzle 7 is opened and closed by vertical movement of the needle 522.

Other configurations and operations are the same as in the first embodiment.

In the above embodiment, a gear pump was used as the high-pressure pump 1, but a sub-type pump or a VE-type pump that is normally used in diesel engines may also be used. It is also possible to use the effect.

Furthermore, in the first and second embodiments, the aperture 527 was provided integrally with the needle 522;
22 and may be provided in parallel.

Furthermore, in the first and second embodiments, the electric on-off valve 51 and the hydraulic on-off valve 52 are integrally formed as the fuel control valve 5, but of course they are formed as separate bodies, and they are combined to fuel the fuel. It may also be used as the control valve 5.

As described above, if the fuel supply valve of the present invention is used,
The injection start timing and injection period of high-pressure fuel can be controlled with extremely high precision with a small amount of force.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing the first embodiment of the present invention;
, 3 and 4 are cross-sectional views showing the operation, FIG. 5 is a diagram showing the signal sent to the electric on-off valve and the opening and closing of the hydraulic on-off valve, and FIG. 6 does not show the second embodiment. It is a schematic cross-sectional view. 1...High pressure pump, 51...Electric on-off valve, 52...
...Hydraulic on-off valve, 501...Input boat 502.
...Drainbow), 524...First hydraulic chamber, 525
...Second hydraulic chamber, 527...Aperture, 528...Output port. Representative Patent Attorney Takashi Okabe

Claims (1)

[Claims] 1) A first hydraulic chamber having a drain boat for draining fuel, a second hydraulic chamber having an input boat for receiving fuel from a high-pressure pump and an output port for discharging fuel; an electric on-off valve that opens and closes communication between the first hydraulic chamber and the drain boat according to a signal;
a hydraulic opening/closing valve that opens and closes communication between the second hydraulic chamber and the output port based on a pressure difference between the first hydraulic chamber and the second hydraulic chamber; and between the first hydraulic chamber and the second hydraulic chamber. A fuel supply valve characterized in that it is equipped with a throttle provided in the fuel supply valve.