JPS59190465A - Fuel control device - Google Patents

Abstract

PURPOSE:To improve the responce of a fuel control device, by providing such an arrangement that there are provided two relief ports for returning fuel to a tank, and one of the ports is opened by means of a solenoid valve to produce a pressure differential, thereby fuel is returned through the other port. CONSTITUTION:An attaching member 828 is formed thein with a relief port 829 which is communicated with a pump chamber through a lateral hole 821f, a longitudinal hole 821e, a relief chamber 827c, a relief port 829 and a relief chamber 13b. When a solenoid valve opens a small hole 821b, the pressure differential in the vicinity of a spool 822 increases, resulting in displacing the spool 822 which therefore opens an annular groove 827. With this arrangement, fuel is promptly returned to a tank so that fuel supply to a fuel nozzle is interrupted.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention is incorporated into a part of a fuel supply system of an internal combustion engine,
The present invention relates to a fuel control device that recirculates fuel discharged from a pump to a tank or stops this recirculation in order to stop or start fuel supply to a fuel injection nozzle.

BACKGROUND OF THE INVENTION Conventionally, as a fuel control device of this type, there has been one in which an IJ port for recirculating fuel to a tank is controlled to open and close by a solenoid valve. However, in order to instantly stop fuel injection and discharge a large amount of fuel from this 1,11J leaf port, for example, it is necessary to increase the flow area of the IJ leaf port, so the solenoid valve must be made larger. Must be. In other words, it is necessary to increase the size of the solenoid in order to increase the amount of lift of the valve body, and also to make the part of the valve body into which the solenoid fits sharply, making the entire device expensive and making it difficult to obtain sufficient response. The problem arises that it is difficult.

OBJECTS OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is intended to improve responsiveness and, in particular, to simplify the piping system and downsize the structure.

Structure of the Invention A first aspect of the present invention is a cylindrical cylinder that communicates with a pressure chamber in a high-pressure pump that pumps fuel to a fuel injection nozzle, and that has first and second relief boats for circulating fuel. a member, and a spool having a cylindrical shape and slidably fitted into the cylinder member, having an internal hole that constantly communicates the pressure chamber and the first relief boat, and an outer peripheral side surface of which opens and closes the second relief boat. , an electrically operated valve for opening and closing the first relief boat;
and a second relief boat communicates with the high-pressure pump outside the internal hole, and when the electrically operated valve opens the first relief boat, a pressure difference is generated near the spool and the second relief boat is connected to the high-pressure pump. The spool is displaced,
As a result, the second relief boat opens, the fuel flows back into the high pressure pump via the first and second relief boats, and the fuel supply to the fuel injection nozzle is stopped. .

A second aspect of the present invention also provides a cylindrical cylinder member that communicates with a pressure chamber in a high-pressure pump that pumps fuel to a fuel injection nozzle and has first and second relief boats for circulating fuel. a spool that has a cylindrical shape and is slidably fitted into the cylinder member, has an internal hole that constantly communicates the pressure chamber and the first relief boat, and has an outer circumferential side that opens and closes the second relief boat; 1st
an electrically operated valve that opens and closes a relief boat, the first and second relief boats communicate with the high pressure pump outside the internal hole, and the electrically operated valve opens and closes the first relief boat. By blocking the spool, the pressure difference in the vicinity of the spool is reduced and the spool is displaced, thereby blocking the second relief boat,
The present invention is characterized in that fuel stops flowing back into the high-pressure pump through the first and second relief ports, and fuel supply to the fuel injection nozzle starts.

Example The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 shows a device already proposed by the present inventors. As the high-pressure pump 1, a distribution pump that is normally used as an injection pump is used, but the high-pressure pump does not need a governor and a timer. The plunger 11 of the high-pressure pump 1 is driven by an engine (not shown), and rotates and reciprocates synchronously at 1/2 rotation of the engine. The first notch groove 12 of the plunger 11 is connected to the cylinder 13.
During the suction stroke, the plunger 11 moves to the left in the figure and sucks fuel oil into the pressure chamber 131 formed by the cylinder 13 and the tip of the plunger 11. Second notch groove 15 of plunger
The discharge stroke is when the cylinder 13 and the discharge port 16 of the cylinder 13 are electrically connected to each other, and the plunger 11 moves to the right in the figure while pumping fuel oil from the pressure chamber 131 through the notch groove 15 and the discharge port 16 to the high pressure line. Send it out on the 18th. The time when the plunger 11 starts to move to the right is sufficiently earlier than the time when the injection nozzle 2 is requested to start injection, and the time when the plunger 11 stops moving to the right is when the injection nozzle 2 is requested to stop injection. A fixed time is given that is sufficiently later than the time.

The fuel in the tank is pumped by the feed pump 3 via the low pressure line 17 and supplied to the intake port 14 of the cylinder 13. Due to the action of the high pressure pump 1, the cylinder 13
The fuel discharged from the discharge port 16 is supplied to the injection nozzle 2 via the high pressure line 18. The pressure in the pressure chamber 131 is controlled by the fuel control device 8 as described below.

The fuel control device 8 includes a solenoid valve 8 as an electric on-off valve.
1 and a spool valve 82 as an oil field type on-off valve.

The spool valve 82 is connected to the cylinder portion 4J'821. Spool 8
22, and a spring 823. Spool 82
2 has a cylindrical shape and is fitted into a cylinder member 821 so as to be slidable in the left and right directions in the figure, and hydraulic chambers 824 and 825 are formed at the left and right ends of the cylinder member 821, respectively. The left hydraulic chamber 825 is directly connected to the pressure chamber 131, and is always communicated with the right hydraulic chamber 824 via a restriction 826 formed in the central axis of the spool 822. Right hydraulic chamber 8
A spring 823 is provided within 24, and this spring force constantly presses the spool 822 to the left. When the hydraulic pressure in the left hydraulic chamber 825 is sufficiently larger than the hydraulic pressure in the hydraulic chamber 824, the spool 822 moves to the right against the spring 823, and the left end surface 822b of the spool 822 touches the inner peripheral surface of the cylinder member 821. At 4 o'clock, when the fuel in the left hydraulic chamber 825 overlaps with a part of the formed annular groove 827, the fuel in the left hydraulic chamber 825 is relieved to the drain line 71 through this annular groove 827.

The right hydraulic chamber 824 is connected to the drain line 71 by the solenoid valve 81 . The solenoid valve 8] is composed of a valve, a nod 811, a valve body 812, a small hole 812b, and a spring 813. When the solenoid 811 is energized, the valve body 812 moves to the right against the spring 813, and the small hole 812 moves to the right. The hole 812b is open. When the solenoid valve 81 is opened, the fuel in the hydraulic chamber 824 is relieved to the drain line 71. Solenoid 81
1 is supplied with electricity via a lead wire 814 by an external controller (not shown).

The computer 20 energizes the solenoid 811 of the solenoid valve 81 . The computer 20 energizes the solenoid 811 at an appropriate time and for an appropriate period according to the signals of the accelerator opening degree and the pump rotation speed. The accelerator opening signal is a potentiometer 211 provided on the accelerator pedal 21.
Sent by. Engine phase signals for determining the pump rotation speed and timing are transmitted by two MRE (magnetoresistive element) sensors 41 and 42 provided on the pump housing 4. The sensor 42 detects the unevenness of a gear 51 fixed to the drive shaft 5 that rotationally drives the plunger 11, and the sensor 41 detects one protrusion 511 provided on the side surface near the outer periphery of the gear 51. That is, the sensor 42 detects the unevenness of the teeth provided at 5° intervals I7. It sends 72 pulse signals per revolution to the computer 20, and the sensor 41 sends one pulse signal per revolution to the computer 20. . Based on these signals, the computer 20 calculates the injection start timing and end timing and energizes the solenoid 811.

Next, the basic operation of the fuel control device 8 will be explained in FIGS. 2(a) to 2(a).
This will be explained using (c) together.

■ When the IJ IJ valve is stopped (at the start of injection and during the injection period), the computer 20 stops energizing the solenoid 811, and as a result, the valve body 812 is pushed to the left by the elastic force of the spring 813, and the small hole is closed. Block 812b. Therefore, all of the relief passages of the fuel control device 8 are closed, and substantially all of the fuel discharged from the high-pressure pump 1 is supplied to the injection nozzle 2 via the notch groove 15 and the high-pressure line 18 (see Fig. 2). a)).

■ At the start of relief (at the end of injection), computer 20
energizes the solenoid 811, and as a result, the valve body 8
12 is sucked to the right to open the small hole 812b. That is, the fuel is supplied to the hydraulic chamber 825, the throttle 8'26, and the hydraulic chamber 82.
4. Start relief via the branch pipe 711 of the drain line and the drain line 71 (see FIG. 2(b)).

■ When the small hole 812b opens, the pressure in the right hydraulic chamber 824 is reduced by the throttle f) 826 provided in the spool 822, and the spool 822 increases the force of the spring 823 according to the pressure difference in the hydraulic chambers 825 and 824. Move to the right against the When the left end surface 822b of the spool 822 and the annular groove 827 of the cylinder member 821 communicate with each other, most of the fuel flows through the hydraulic chamber 825, the ffl-shaped groove 827, the drain line/branch pipe 712, and the drain line 71. It is returned to the tank 7 and a large amount of main IJ-flow is performed (see FIG. 2(c)).

As described above, in this device, when the small hole 812b is opened only slightly, the spool 822 is displaced, making it possible to instantly discharge a large amount of fuel.

Now, in the fuel control device 8 having the above configuration, the small hole 812
When b opens, fuel flows through three branch pipes 711°712.7
13 to the drain line 71, and is sent to the tank 7
It is flowing back to. That is, the drain line 71 is required to recirculate the fuel to the tank 7, and the fuel passing through the small hole 812b flows through the annular groove 82 through the branch pipe 711.
7, the fuel passes through a branch pipe 712 to a solenoid valve 81.
The fuel inside the solenoid 811 and behind the valve body 812 is connected to the drain line 71 via a branch pipe 713.
A large number of branch pipes are required to route the water to the

The device according to the present invention connects these branch pipes 711, 712°71
3 and the drain line 71 are omitted, and the relieved fuel is returned into the contact high pressure pump 1.

FIG. 3 shows an embodiment of the present invention, and points different from the configuration shown in FIGS. 1 and 2 will be explained.

The cylinder member 821 includes a cylindrical cylinder ring 821c, a distance piece 821d located at one end of the cylinder ring 821c, and a valve body 8 located at the other end of the cylinder ring 821c, the central protrusion of which fits into the cylinder ring 821c.
Consists of 21h. The seal between the cylinder member 821 and the spool 822 is such that the circumferential portion is the cylinder ring 821c.
The end surfaces are each formed using a distance piece 821d. The reason why the cylinder member 821 is composed of a plurality of members in this manner is to facilitate polishing and lapping. The central protruding part of the grooved valve body 821h is housed in the hydraulic chamber 824 in order to minimize the volume of the hydraulic chamber 824, and a small hole 8 is formed at its tip.
12b is bored, and a valve body 812 for opening and closing this small hole 812b is slidably fitted inside. Thus, when the small hole 812b is opened, a pressure difference is quickly created on both sides of the restriction 826, and when the small hole 812b is closed, the pressure difference on both sides of the restriction 826 is quickly reduced to zero.
The spool 822 moves faster, improving responsiveness.

The edge position of the annular groove 827 is
This is to match the end face position of 21d. As a result, fuel relief is started at the same time as the spool 822 starts moving, and responsiveness is further improved.

The gauging 83 accommodates and fixes the cylinder member 821 and is provided with the above-mentioned solenoid valve 81.
through the gauge/jar 1 of the gauging 4 of the high pressure pump 1
It is screwed onto the opposite surface side of 1. A QIJ ring 43 is provided on the outer peripheral edge of the mounting member 828, thereby completely blocking the inside of the Jikusuing 4 from the outside. The annular protrusion 828b provided on the end surface of the mounting portion 823 is in close contact with the end surface of the cylinder member 13 of the high-pressure pump 1, and seals the pressure chamber 131 from the outer circumferential side. A drain hole 44 is formed in the cylinder member 13 in the axial direction, and fuel leaking from between the annular projection 828b and the end surface of the cylinder member 13 is drained through the annular projection 8
The water is returned to the pump chamber 45 through the drain chamber 13b1 and the drain hole 44 on the outer periphery of the pump 28b.

A relief chamber 827C that communicates with the annular groove 827 via a relief hole 827b is formed between the end surface of the gauging 83 and the mounting portion 828. The relief chamber 827C is
It communicates with the drain chamber 13b via a relief boat 829 bored in the mounting member 828. Therefore, the annular groove 82
7 is IJ IJ-F hole 827b, relief chamber 827e
, communicates with the inside of the pump chamber 45 via the relief port 829, the drain chamber 13b1, and the drain hole 44.

Inside the casing 83, there is a vertical hole 821e extending in the axial direction and communicating with the IJ+F chamber 827C, and a relief chamber 827.
A horizontal hole 821f is located on the opposite side of the vertical hole 821e and communicates with the vertical hole 821e. The horizontal hole 821f is the bin 82 after processing.
It is sealed from the outside by implanting 1g and welding. Casing 83 and valve body 821h and valve body 81
The valve chamber 812d formed by the horizontal hole 821
Therefore, this valve chamber 812d communicates with the horizontal hole 821f, the vertical hole 821e, and the relief chamber 827c.
, communicates with the inside of the pump chamber 45 via the relief port 829, the drain chamber 13b, and the drain hole 44.

The valve body 812 has a small diameter portion 812e at the tip and a sliding portion 81 at the center.
2f and a suction part 812 that fits into the flenoid 811
Configure g. The sliding part 812f and the suction part 812g are
Each negative side portion slides into the fitting hole, while the other side portion is spaced apart from the wall surface of the fitting hole.

Therefore, the fuel relieved by the small hole 812b is
A spring chamber 813b that passes through the small diameter portion 812e and the outer circumferential side of the sliding portion 812f and enters the valve chamber 812d, and accommodates the plug 813 located on the right side of the suction portion 812g.
The fuel inside can freely flow into the valve chamber 812d through the outer peripheral side of the suction portion 812f.

Thus, the fuel passing through the small hole 812b and the fuel in the spring chamber 813b are returned to the pump chamber 45.

As described above, in this embodiment, the IJ IJ-
A horizontal hole 821 f and a vertical hole 82 are formed.
1e, the pump chamber 45 via the relief chamber 827c, the relief boat 829, and the IJ-) chamber 13b.
It is constructed so that it communicates with the inside. Therefore, there is no need for drain piping outside the device, resulting in a compact structure.

In each of the above-mentioned embodiments, the present invention is applied to the case of stopping fuel supply, but contrary to the above-mentioned embodiments, the present invention can be applied to the case of starting fuel supply. That is, when the solenoid valve 81 closes the small hole 812b, the pressure difference near the spool 822 decreases and the spool 822 is displaced, thereby closing the annular groove 827. As a result, the fuel recirculation is immediately stopped and fuel supply to the fuel injection nozzle is started.

Effects of the Invention As described above, according to the present invention, the effects of improving responsiveness and simplifying the piping system can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a device already proposed by the present inventors,
FIGS. 2(a), (b), and (c) are sectional views showing various states of fuel relief in the apparatus shown in FIG. 1, and FIG. 3 is a sectional view showing one embodiment of the apparatus of the present invention. 1...High pressure pump, 2...Fuel injection nozzle, 8...
- Fuel control device, 81... Solenoid valve (electrically operated valve), 131... Pressure chamber, 821b... Small hole (first
relief port)), 821... cylinder member, 822
... Spool, 827 ... Annular groove (second relief boat). Patent Applicant Japan Auto Parts Research Institute Co., Ltd. Patent Application Agent Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Kyo Nakayama Akira Yamaguchi

Claims (1)

[Claims] 1. A first valve that communicates with a pressure chamber in a high-pressure pump that pumps fuel to a fuel injection nozzle and that circulates fuel.
and a cylindrical cylinder member having a second relief port, which has a cylindrical shape and is slidably fitted into the cylinder member, and has an internal hole that constantly communicates the pressure chamber and the first relief port, and an outer circumferential side surface of the cylinder member. includes a spool that opens and closes the second relief port, and an electrically operated valve that opens and closes the first relief port, and the first and second relief ports communicate with the high pressure pump outside the internal hole. When the electrically operated valve opens the first relief boat, a pressure difference is generated in the vicinity of the spool and the spool is displaced, thereby causing the second relief boat to open.
The relief port opens and fuel flows into the first and second ports.
17! , l-7 through the high-pressure pump, and the fuel supply to the fuel injection nozzle is stopped. 2. A first pipe that communicates with the pressure chamber in the high-pressure pump that pumps fuel to the fuel injection nozzle and that circulates the fuel.
and a cylindrical cylinder member having a second relief port, which has a cylindrical shape and is slidably fitted into the cylinder member, and has an internal hole that constantly communicates the pressure chamber and the first relief port, and an outer circumferential side surface of the cylinder member. comprises a spool that opens and closes the second relief port, and an electrically operated valve that opens and closes the first relief boat, and the first and second relief ports communicate with the high pressure pump outside the internal hole. When the electrically operated valve closes the first relief boat, the pressure difference in the vicinity of the spool decreases and the spool is displaced, thereby blocking the second relief port and draining the fuel. A fuel control device, wherein the fuel stops flowing back into the high-pressure pump through the first and second relief ports, and starts supplying fuel to the fuel injection nozzle.