JP2002061548A - Solenoid valve used for common rail type fuel injection device and relief in common - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent performance deterioration such as sticking or defective opening of a relief valve in a common rail type fuel injection device. SOLUTION: In this common rail type fuel injection device, a solenoid valve 52 is composed as a poppet type solenoid valve, that is a solenoid valve also operable for relief in which it is closed at a poppet part when not energized, and in which a poppet makes relief action when not energized. The solenoid valve 52 is composed of a seat 14 provided between a high pressure port 15 and a low pressure port 28, a plunger 11 having the poppet part 14 which can be removed from or seated on the seat 14 from the low pressure port side, a spring 13 to energize the plunger 11 toward the seat 14, a regulation part 17 capable of regulating pressure using energization force of the spring 13 as relief valve pressure, and a solenoid coil 16 to magnetically attract the plunger 11 when energized to remove the poppet part 14 from the seat 14 against energization force of type spring 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a common rail type fuel injection system for adjusting a fuel discharge amount of a high pressure fuel pump to inject high pressure fuel of an internal combustion engine via a common rail. Further, the present invention relates to a relief / solenoid valve having a relief function suitable for this device.

[0002]

2. Description of the Related Art Conventionally, in a common rail type fuel injection device, a valve of a high pressure fuel pump is opened without energizing a solenoid of a spill (overflow) valve, and oil discharged from a piston of the high pressure fuel pump is supplied to a common rail side. When the power is supplied to the solenoid without returning to the tank (injector side) and the solenoid is energized, the spill valve closes and the oil pushed out from the plunger is discharged to the common rail side through the check valve. The common rail pressure is set by a relief valve installed on the common rail.

When a relief valve is installed on a common rail, the pressure of the common rail becomes excessive and the relief valve is rarely opened. If the relief valve is left closed for a long time, it is contained in fuel. The relief valve may stick due to impurities (gum content) and the like, resulting in malfunction. Therefore, in Japanese Patent Application Laid-Open No. 10-17618, the control of increasing the pressure of the common rail is performed so that the relief valve is opened each time the engine is started.

[0004]

However, in this case, opening the relief valve set at a high pressure and flowing the flow rate is a waste of energy, and the pressure at the time of starting the engine is usually reduced. A higher value causes a problem that the load of the starter motor is increased because the engine is rotated by the starter motor at the start. On the other hand, a control solenoid valve for spilling (overflowing) high-pressure fuel controls a spill amount of high-pressure fuel by removing and seating a poppet on a seat provided between a high-pressure port and a low-pressure port. There is no one.

[0005] In view of the above problems, an object of the present invention is to provide:
An object of the present invention is to prevent a reduction in performance of a common rail type fuel injection device such as a sticking of a relief valve and a defective valve opening without increasing a load at the time of starting and consuming unnecessary energy. Another object is to provide a solenoid valve suitable for such a device.

[0006]

According to a first aspect of the present invention, a part of fuel discharged by a high pressure fuel pump is returned to a low pressure side or a fuel tank by a solenoid valve. In a common rail fuel injection device adapted to supply to a common rail for injecting via an injector provided in each cylinder of an internal combustion engine, the solenoid valve is a poppet type solenoid valve. The above-mentioned problem has been solved by providing a common rail type fuel injection device which is a closed / solenoid valve which is closed and which operates as a relief when the poppet portion is not energized. That is, by using a solenoid valve (spill valve) as a normally closed solenoid valve and having a pressure adjusting mechanism, the relief valve previously installed on the common rail can be eliminated. Further, since the solenoid valve is always opened and closed for control, the poppet portion also serving as relief is not closed for a long time, and the relief valve is not fixed by impurities contained in fuel.

A solenoid valve suitable for such a device is
More specifically, as in the invention of claim 2, a seat provided between a high-pressure port and a low-pressure port, a plunger having a poppet portion capable of taking off and seating on the seat from a low-pressure port side, and connecting the plunger to the seat A spring for biasing the spring, and an adjusting portion capable of adjusting the biasing force of the spring,
It is preferable that the plunger is a magnetic valve which is magnetically attracted when energized, and a solenoid coil having a solenoid coil for separating the poppet from the seat against the urging force of the spring. That is, the pressure can be easily adjusted by strengthening the spring that presses the plunger to provide a relief valve function and to adjust the biasing force of the spring. Also, the solenoid coil has a spill function by acting as a suction force stronger than a spring, and also functions as a spill valve.

The solenoid valve is of a so-called direct acting type. In the case of the direct-acting type, if the control flow rate is increased, the seat area must be increased, so that the spring and the solenoid coil also increase. Therefore, in the invention of claim 3, a cylinder is further provided on the high pressure port side of the seat, and a main valve seat having an opening on the opposite side of the cylinder from the seat is provided, and the main valve seat is provided in the cylinder. A main valve removably slidable and seatable on a seat and sliding in a cylinder in a liquid-tight manner, and a main spring for urging the main valve toward the main valve seat; providing a main valve, the cylinder, and the main valve; A low-pressure part formed by the outside of the valve seat and a high-pressure part formed by the inside of the main valve and the cylinder and communicating with the seat are provided, and inside the main valve seat detaching seat part of the main valve. A restrictor communicating the opening and the high-pressure section was provided, and the low-pressure section and the low-pressure port were connected. That is, a balance-type relief / solenoid valve was used.

The above-described relief / solenoid valve of the present invention has a relief function and a spill (overflow) function integrated with each other, and can be applied to a circuit in which a relief is added to a general hydraulic bleed-off circuit. But,
In particular, a common rail for controlling a part of the fuel discharged by the high-pressure fuel pump to return to the low-pressure side or the fuel tank, and injecting the controlled high-pressure fuel through an injector provided in each cylinder of the internal combustion engine. When it is used for a common rail type fuel injection device supplied to a vehicle, it is suitable in terms of capacity, pressure, etc. (Claim 4).

A part of the fuel discharged from the high-pressure fuel pump is returned to the low-pressure side or the fuel tank by a solenoid valve, and the controlled high-pressure fuel is supplied through injectors provided in each cylinder of the internal combustion engine. 3. A common rail fuel injection device adapted to supply to a common rail for injection, wherein the solenoid valve is provided.
Alternatively, the relief / solenoid valve according to the third aspect can be provided (claim 5).

[0011]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration of a common rail type fuel injection device of the present invention, and FIG. 2 is a sectional view of a relief / solenoid valve of the present invention used in FIG.
In FIG. 1, this common rail type fuel injection device guides a fuel supplied from a low pressure feed pump 54 to a pressure chamber 3 of a high pressure fuel pump 51 to make it a higher pressure fuel, and a part of the fuel discharged at a high pressure is solenoid valve ( Spill valve)
52, the fuel tank 5 through the low pressure side check valve 65.
3 and supplies the controlled high-pressure fuel to the common rail 62, and further controls the engine by injecting fuel into the engine via injectors 63 provided in each cylinder of the internal combustion engine 66. .

In the present invention, as shown in FIGS. 1 and 2, a relief valve function is added to the solenoid valve 52 for controlling high-pressure fuel. That is, the solenoid valve 52 includes a seat 14 provided between the high-pressure port 15 and the low-pressure port 28, a plunger 11 having a poppet portion 12 which can be detached from and seated on the seat from the low-pressure port side, and a spring for urging the plunger toward the seat. 13 are provided. The plunger 11 slides inside the guide 18 and can move up and down as seen in the figure. A solenoid coil 16 is provided so as to surround the guide 18 and to magnetically attract the plunger 11 when energized and to separate the poppet from the seat against the urging force of the spring. The energizing force of the solenoid coil 16 during energization is
The poppet portion 12 is separated from the seat 14 by energizing the solenoid coil to communicate the high-pressure port 15 and the low-pressure port 28 to discharge from the pressure chamber of the high-pressure fuel pump 51. A part of the fuel to be used can be returned to the fuel tank 53. Further, an adjusting portion 17 capable of adjusting the urging force of the spring 13 is provided. Adjusting part 17 has tip 17c
Abuts against the end of the spring 13 and is screwed into the guide 18 by the screw 17b, and the pressure can be easily adjusted by rotating the screw. Reference numeral 17a is a lock nut for fixing the screw 17b.

The fuel sent from the tank 53 by the low-pressure feed pump 54 passes through a fuel filter 55 and a check valve 56,
It is led to the pressure chamber 3. A pressure regulator valve 59 is provided in front of the check valve 56 to keep the pressure of the fuel oil entering the pump chamber 3 constant. A safety valve 67 for protecting the low-pressure feed pump 54 by branching from just before the fuel filter 55 is provided. The fuel guided to the pressure chamber 3 is sucked and discharged by a piston 58 which moves up and down along a cam 57 driven by an engine (not shown). The discharged fuel passes through a communication passage 60 and is communicated with a relief / shared solenoid valve (spill valve) 52 and a discharge-side check valve 61. The fuel oil that has passed through the check valve 61 flows to the common rail 62 and is maintained at a high pressure. A plurality of injectors 63 are attached to the engine corresponding to each cylinder and injected. The common rail 62 is provided with a sensor 64 for measuring the fuel pressure. A signal is sent from the electronic control unit ECU to the solenoid of the relief / shared solenoid valve 52 so that the pressure of the common rail 62 becomes the required pressure. The relief / shared solenoid valve 52 is operated so as to flow.

When a signal is not supplied to the relief / shared solenoid valve 52, the poppet portion 12 is
Is seated on the seat 14, the valve is closed and the piston 5
8 is discharged to the common rail 62.
On the other hand, the piston stroke when the piston 58 rises is 1
When a signal is input to the relief / shared solenoid valve 52 at the time of / 2, and the solenoid coil is energized, the poppet portion 12 is separated from the seat 14 due to the urging force of the spring 13 and the high-pressure fuel is supplied to the low-pressure port 28 and the check valve. It is returned to the fuel tank 53 through 65. Therefore, 1/2 of the stroke of the piston 58 flows to the common rail 62 and 1/2 of the fuel flows to the tank 53, so that the amount of fuel supplied to the common rail can be controlled.

When the supply pressure of the common rail 62 exceeds a predetermined pressure, the pressure of the communication passage 60 is applied to the poppet portion 12, and the poppet portion, that is, the plunger 11 is moved by the spring 13.
And the excess fuel in the communication passage 60 is returned to the tank 53 via the check valve 65. Thereby, it works as a relief valve so that the common rail pressure does not become excessive. An emergency safety valve for preventing a pressure increase due to a temperature rise of the fuel supplied to the common rail side and closed by the check valve 61 or the like may be provided as in the related art.

Next, a description will be given of a balanced relief / shared solenoid valve according to the present invention. FIG. 3 is a cross-sectional view of the balanced relief / solenoid valve of the present invention. The circuit used is the same as in FIG. 1 and will not be described. In FIG. 3, a relief / combination solenoid valve is a direct acting relief / combination solenoid valve (hereinafter referred to as a solenoid valve) 1 as the electric on / off valve described in FIG.
And a spool valve 2 as a hydraulic on-off valve.
The direct-acting / relief solenoid valve is the same as that shown in FIG. The spool valve 2 is a cylinder 2 provided on the high pressure port 15 side of the seat 14 of the direct acting type solenoid valve 1 for relief.
3. A main valve seat 29 having an opening 24 on the opposite side of the cylinder from the cylinder, and a main valve 21 which can be detachably seated on the main valve seat in the cylinder and slides in the cylinder in a liquid-tight manner. Further, a low-pressure portion 27 formed by the main valve 21, the cylinder 23 and the outside of the main valve seat 29, and a high-pressure portion 25 formed by the inside of the main valve 21 and the cylinder 23 and communicating with the seat 14 are provided. ing. A throttle 26 that connects the opening 24 and the high-pressure portion 25 is provided inside the main valve seat detaching seat portion of the main valve 21, and the low-pressure portion 27 is connected to the low-pressure port 28 through a communication hole 30. The opening 24 is connected to a communication passage 60 through which fuel is discharged from the high-pressure fuel pump 51. The main valve 21 has a poppet-shaped seat portion 21 a that comes into contact with the main valve seat 29, and is pressed against the main valve seat by the main spring 22.

When the solenoid valve 1 is not energized, the poppet 12 press-fitted into the plunger 11 is pressed against the seat 14 by the spring 13 and the opening 24 and the high-pressure portion 25 have the same pressure.
Is pressed against the main valve seat 29 to close the main valve 21. When the solenoid valve 1 is energized, the plunger 11 is attracted upward, the poppet 12 separates from the seat 14, and the fuel in the high pressure section 25 flows from the high pressure port 15 to the low pressure port 28. The fuel supplied from the communication path 60 and the opening 24 to the high-pressure section 25 passes through the throttle 26 of the main valve 21, so that the pressure in the high-pressure section falls below the pressure in the opening 24. The main valve 21 moves away from the main valve seat 29, and the fuel in the opening 24 passes through the low-pressure portion 27 and the communication hole 30 to the low-pressure port 28. It is returned to the tank 53.

If the pressure in the pump chamber 3 rises while the solenoid valve 1 is not energized, the pressure in the opening 24 and the high pressure section 25 rises, and the poppet 12
When the force due to the pressure applied to the pressure receiving area becomes larger than the force pressed by the sheet 14 in 3, the poppet 12 rises from the sheet 14, and the fuel in the high-pressure section 25 flows to the low-pressure port 28. The pressure of the high pressure section 25 is controlled by the throttle 26 of the main valve 21.
The main valve 21 moves upward due to the pressure difference, and the fuel in the opening 24 flows through the low-pressure section 27 to the low-pressure port 28. That is, the pressure of the pump chamber 3 can be set by adjusting the force of the spring 13. As described above, it is also possible to provide a balanced relief / solenoid valve.

[0019]

In the conventional spill valve without a relief function, it was necessary to provide a relief valve on the common rail in order to limit the pressure on the common rail. Also, in order to prevent the relief valve from sticking, it was necessary to set up a system for increasing the circuit pressure in order to operate the relief valve periodically. In the present invention, by providing the spill valve with a relief function, the relief valve installed on the common rail can be omitted, and the cost can be reduced. In addition, since the relief / solenoid valve of the present invention controls the high-pressure fuel supplied to the common rail, the opening / closing operation is constantly repeated, and there is no sticking due to fuel impurities.
Further, since it is not necessary to increase the circuit pressure in order to prevent sticking, the load at the time of starting is not increased, and unnecessary energy is not consumed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration of a common rail fuel injection device of the present invention.

FIG. 2 is a cross-sectional view of a direct acting relief / combination solenoid valve of the present invention used in the common rail type fuel injection device of the present invention.

FIG. 3 is a cross-sectional view of the balanced relief / solenoid valve of the present invention used in the common rail fuel injection device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Direct-acting relief combined use solenoid valve (solenoid valve) 2 Spool valve 3 Pump chamber 11 Plunger 12 Poppet part 13 Spring 14 Seat 15 High pressure port 16 Solenoid coil 17 Adjusting part (screw) 18 Guide 21 Main valve 21a Seat part 22 Main spring 23 Cylinder 24 Opening 25 High pressure section 26 Restrictor 27 Low pressure section 28 Low pressure port 29 Main valve seat 51 High pressure fuel pump 52 Relief / solenoid valve (spill valve) 53 Fuel tank 54 Low pressure feed pump 55 Fuel filter 56 Check valve 57 Cam 58 piston 59 pressure regulator valve 60 communication passage 61 check valve 62 common rail 63 injector 64 sensor 65 check valve 66 internal combustion engine (engine) 67 safety valve

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16K 31/06 330 F16K 31/06 330 (72) Inventor Yama ▲ saki ▼ Geichi Fujikoshi Honcho, Toyama City, Toyama Prefecture 1-1 1-1 Fujikoshi Co., Ltd. (72) Inventor Kenichi Kato 1-1-1 Fujikoshi Honcho, Toyama City, Toyama Prefecture F Term (reference) 3G066 AA07 AB02 AC09 BA30 CB15 CE22 DB01 DC01 3H059 AA04 AA07 AA17 BB06 BB22 BB34 CD05 CE01 DD07 DD13 EE01 FF03 FF12 FF13 3H106 DA03 DA13 DA23 DB02 DB12 DB22 DC02 DC17 DD03 EE22 EE27 GC29 KK18

Claims (5)

[Claims] 1. A part of fuel discharged by a high-pressure fuel pump is returned to a low-pressure side or a fuel tank by a solenoid valve, and controlled high-pressure fuel is supplied through an injector provided in each cylinder of an internal combustion engine. In a common rail type fuel injection device adapted to be supplied to a common rail for injecting, the solenoid valve is a poppet type solenoid valve, which is closed at a poppet portion when not energized, and when the poppet portion is not energized. A common rail type fuel injection device characterized in that it is a relief / combination solenoid valve adapted to act as a relief. 2. A seat provided between a high-pressure port and a low-pressure port, a plunger having a poppet portion that can be detached from and seated on the seat from the low-pressure port side, a spring for urging the plunger to the seat, and a spring An adjusting part capable of adjusting the biasing force of the solenoid, a solenoid coil that magnetically attracts the plunger when energized and separates the poppet from the seat against the biasing force of the spring;
A relief / solenoid valve characterized by having: 3. A high-pressure port side of the seat according to claim 2, further comprising a cylinder, and a main valve seat having an opening on a side opposite to the seat side of the cylinder, wherein the main valve seat is provided in the cylinder. A main valve that can be detached from and seated on the main valve seat and slides in the cylinder in a liquid-tight manner, and a main spring that biases the main valve against the main valve seat; and the main valve and the cylinder A low-pressure portion formed by the main valve seat and the high-pressure portion formed by the inside of the main valve and the cylinder and communicating with the seat. 3. The relief / solenoid valve according to claim 2, further comprising: a throttle communicating the opening and the high-pressure portion inside the seat portion, wherein the low-pressure portion is connected to a low-pressure port. 4. A relief / solenoid valve according to claim 2 or 3, wherein a part of the fuel discharged by the high-pressure fuel pump is controlled to return to a low-pressure side or a fuel tank, and the controlled high-pressure fuel is supplied to the internal combustion engine. The relief / solenoid valve according to claim 2 or 3, wherein the solenoid valve is used for a common rail type fuel injection device which is supplied to a common rail for injecting through an injector provided in each of the cylinders. 5. A part of the fuel discharged by the high-pressure fuel pump is returned to a low-pressure side or a fuel tank by a solenoid valve, and the controlled high-pressure fuel is supplied through an injector provided in each cylinder of the internal combustion engine. 4. A common rail type fuel injection device, wherein the solenoid valve is the relief / solenoid valve according to claim 2 or 3 in a common rail type fuel injection device adapted to be supplied to a common rail for injection.