JPS59188065A - Fuel control equipment - Google Patents

Abstract

PURPOSE:To simplify and miniaturize the construction of the captioned equipment and also to enhance its response performance by installing said fuel control equipment, which controls stopping or starting of fuel supply to a fuel injection nozzle, in such a manner that it is connected to an injection pump pressure chamber and making the fuel bypass when an electrically operated valve is opened. CONSTITUTION:A fuel control equipment 8 is installed in order to control the pressure in a pressure chamber 131 that is formed with the plunger 11 and the cylinder 13 of a distributor type injection pump 1. The fuel control equipment 8 is formed with a solenoid valve 81 and a spool valve 82. The spool valve 82 is accommodated in a cylinder member 821 and provided with a spool 822 that is usually energized toward the left side by a spring 823. The solenoid valve 81 is provided with a valve body 812 which closes, being energized by the spring force of the spring 813, a relief port 812b that opens to a hydraulic chamber 824 of the spool valve 82. When the solenoid valve 81 is excited to open the valve body 812, the spool valve 82 is opened by pressure difference, making the fuel bypass and suspending fuel supply.

Description

DETAILED DESCRIPTION OF THE INVENTION 1 (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 (5) or stops this recirculation (1) in order to stop or start fuel supply to a fuel injection nozzle.

BACKGROUND ART Conventionally, as a fuel control device of this type, there has been one in which a relief boat for circulating fuel back into a tank is controlled to open and close using an electromagnetic valve. However, if 2 tries to discharge a large amount of fuel from this relief boat in order to instantaneously stop fuel injection, for example.

Since it is necessary to increase the flow path area of the IJ IJ port, the solenoid valve must be increased in size. That is, in order to increase the lift amount of the valve body, it is necessary to increase the size of the solenoid and also to enlarge the part of the valve body into which the solenoid fits, making the entire fruiting device expensive and making it difficult to obtain sufficient responsiveness. The problem arises.

OBJECT OF THE INVENTION In view of the above points, the present invention has been made with the object of providing a fuel control device that is simple and compact and has excellent responsiveness.

Structure of the Invention A first aspect of the present invention is a cylindrical pipe having first and second relief ports communicating with a pressure chamber in a pump that pumps fuel to a fuel injection nozzle and allowing fuel to flow back into a tank. A cylinder member, which 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 IJ port, and an outer peripheral side surface that opens and closes the second relief port. a spool; and an electrically operated valve that opens and closes the first relief port; when the electrically operated valve opens the first relief port, a pressure difference is generated in the vicinity of the spool, and the spool is displaced. Accordingly, the second relief port opens, the fuel flows back, and the fuel supply to the fuel injection nozzle is stopped.

The second aspect of the present invention also provides 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 ports that allow the fuel to flow back into the tank. 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 port, and an outer peripheral side surface of which opens and closes the second relief port. .

and an electrically operated valve that opens and closes the first relief port, and when the electrically operated valve closes the first relief port, the pressure difference in the vicinity of the spool is reduced and the spool is displaced. The present invention is characterized in that the second relief port is then closed, fuel recirculation is stopped, and fuel supply to the fuel injection nozzle is started.

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

FIG. 1 shows a first embodiment of the present invention. 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).
Rotation and reciprocation are performed synchronously with the second rotation. The first notch groove 12 of the plunger 11 is connected to the suction port 1 of the cylinder 13.
4, it is the suction stroke, and plunger 11
While moving to the left in the drawing, fuel oil is sucked into a pressure chamber 131 formed between the cylinder 13 and the tip of the plunger 11. The discharge stroke is when the second notch groove 15 of the plunger and the discharge port 16 of the cylinder 13 are electrically connected, and the plunger 11 cuts fuel oil from the pressure chamber 131 while moving to the right in the figure. Groove 15. High pressure 2 via discharge port 16
Send to In18. 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 actual time.

The fuel in the tank 7 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 10, the cylinder 1
The fuel discharged from the discharge port 16 of No. 3 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 is composed of a solenoid valve 81 as an electric on-off valve and a spool valve 82 as a hydraulic on-off valve.

The spool valve 82 is a cylinder member 821. Spool 822
, and a spring 823. The spool 822 has a cylindrical shape, and is fitted into the cylinder member 821 so as to be slidable in the left and right directions in the figure. Hydraulic chambers 824 and 825 are formed at the left and right ends of the spool 822, respectively. Ru. The left hydraulic chamber 825 is directly connected to the pressure chamber 131 via a constrictor 826 formed at the central axis of the spool 822.

It is constantly communicated with the cloth hydraulic chamber 824. A spring 823 is provided in the right hydraulic chamber 824, and this spring force constantly presses the spool 822 to the left. Left hydraulic chamber 82
When the oil pressure of No. 5 is sufficiently larger than the oil pressure of the oil pressure chamber 824,
The spool 822 moves to the right against the spring 823, and the left end surface 822b of the spool 822 moves toward the cylinder member 8.
21 , the fuel in the left hydraulic chamber 825 is relieved to the drain line 71 via this annular groove 827 .

The right hydraulic chamber 824 is connected to the drain line 71 by the solenoid valve 81 . The solenoid valve 81 is a solenoid 811. It is composed of 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 812b comes into contact with the valve body 812. There is. When the solenoid valve 81 opens, the fuel in the hydraulic chamber 824 is relieved to the drain line/71. Solenoid 811
An external controller (not shown) supplies power through a lead wire 814.

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 in the pump casing 4. The sensor 42 detects the irregularities of a gear 51 fixed to the drive shaft 5 that rotates 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, and sends a pulse signal of two shifts per rotation to the computer 20.
9° Sensor 41 also transmits 91 pulse signals to computer 20 per revolution. 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).
(C) will be used in conjunction with the explanation.

■ When the relief 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 812b block. Therefore, all of the IJ-F passages of the fuel control device 8 are closed, and substantially all of the fuel discharged from the high-pressure pump 1 goes through the notched groove 15.
and is supplied to the injection nozzle 2 via the high pressure line 18 (see FIG. 2(, )).

■IJ At the start of IJ-F (at the end of injection), the computer 20 energizes the solenoid 81'1.

As a result, the valve body 812 is attracted to the right and opens the small hole 812b. In other words, the fuel flows through the hydraulic chamber 825° and the throttle shaft 826.
．． Hydraulic chamber 824, small hole 812b, drain line 7
1 (see FIG. 2(b)).

■ When the small hole 812b opens, the pressure in the right hydraulic chamber 824 is reduced by the throttle 826 provided in the spool 822, and the spool 822 resists the force of the spring 823 according to the pressure difference in the hydraulic chambers 825 and 824. and move to the right. 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 into the hydraulic chamber 825, the annular groove 827. A large amount of main relief is performed by returning to the tank 7 via the drain line branch pipe 712 and the drain line 71 (second
(See figure (c)).

As described above, in the device of the first embodiment, by opening the small hole 812b only slightly, the spool 822 is displaced, and a large amount of fuel can be instantly relieved. That is,
By using the spool 822, the entire device is extremely simple and compact.

Also, it becomes possible to quickly perform IJ leafing of a large amount of fuel.

Now, in the configuration and operation of the fuel control device 8, the present inventors have further made the following improvements.

This will be explained in detail with reference to FIG.

Let us briefly explain the first improvement point.

The annular groove 827 of the cylinder member 821 in FIGS. 1 and 2 is located a little apart from the cylinder end surface 821b. Therefore, the start time of the main relief is delayed until the spool 822 starts moving and the spool end face 822b communicates with the annular groove 827. Therefore, as shown in FIG. 3, by lowering the edge of the annular groove 827 to the cylinder end surface 821b, the main relief can be started at the same time as the cispool 822 starts moving to the right. As a result, the responsiveness of starting fuel relief is improved, and fuel injection from the fuel injection nozzle 2 is completed more quickly.

Next, the second improvement point will be explained.

As shown in FIG. 2, end face 822 of spool 822
b and the end face 821b of the cylinder 821 perform surface sealing, so these end faces 822b, 821b.

requires highly precise polishing and lapping.

If the cylinder member 821 is constructed in one piece, it will be difficult to process the inner circumferential surface and end surface of the cylinder member 821 when polishing or lapping. Therefore, as shown in FIG. 3, the cylinder member 821 is divided into a cylindrical cylinder ring 821C and a distance piece 821d located at the end thereof. All you have to do is polish and wrap. This facilitates machining of the cylinder end surface 821, and ensures surface sealing of both end surfaces 822b, 821b. In addition, the inner hole of the cylinder end face 821 and the cylinder ring 821C, the cylinder ring 821C and the distance piece 821d, and the distance piece 821
d and the cylinder member 821 is sealed with copper foil (not shown).

The third improvement point will be explained.

If the volume of the right hydraulic chamber 824 in which the spring 823 is housed in FIG.
The time it takes for the spool 822 to open and the pressure difference between the hydraulic chambers 824 and 825 to start moving is long, which puts a certain limit on shortening the time it takes for the main relief to start. . Conversely, the small hole 821b is inserted into the valve body 8.
12, the spool 822 does not close until the pressure in the hydraulic chamber 824 becomes equal to the pressure in the hydraulic chamber 825, making it impossible to obtain sufficient responsiveness.

For this reason, it is preferable to make the volume of the hydraulic chamber 824 as small as possible. Therefore.

As shown in FIG. 3, a pulp body 821h having a small hole 812b is provided in the cylinder member 821, and this pulp body 821h is housed in a hydraulic chamber 824. With this structure, the volume of the right hydraulic chamber 824 can be reduced, and the responsiveness of this device can be further improved.

In FIG. 2, three branch pipes 711, 712, and 713 are required for the 171J-f passage of the present device.

This makes the piping complicated. Therefore, as shown in FIG. 3, the cylinder ring 821c of the cylinder member 821 is
A vertical hole 821e and a horizontal hole 821 are provided in the outer casing 83 of
f and these holes 821e.

821f is communicated with a pulp chamber 812d formed between the valve body 8'12 and the valve body 821h.

The horizontal hole 821f is sealed by welding after a bottle 821g is driven into the casing 83 after processing. The needle pulp 812 consists of a small-diameter seal portion 812e at the tip, a sliding portion 812f, and a suction portion 812g. Sliding part 812f
, the suction portion 812g has a negative side portion slidably in contact with the fitting hole, and the other side portion is spaced apart from the wall surface of the fitting hole,
The fuel relieved from the small hole 812b flows into the sliding part 812e.
and enters the pulp chamber 812d through the other side of the pulp chamber 812d. Further, the fuel in the pulp chamber 812d passes between the other side of the suction portion 812g and the fitting hole, and is relieved through the relief port 71b. This configuration requires only one relief boat, which simplifies piping.

In each of the above embodiments, an electrically acting solenoid valve 81 is used, but the valve is not limited to a solenoid, and may be a valve that utilizes a magnetostrictive effect or an electrostrictive effect.

In the first improvement, the annular groove 827 was formed to match the cylinder end surface 821b, but as shown in FIG. The main relief may be started at the same time as the movement starts.

In addition, in the third improvement, in order to reduce the volume of the hydraulic pressure 824, it was made possible to store it in the pulp body 821h & hydraulic chamber 824, but as shown in FIG.
21h is formed into a substantially flat plate shape, and the spool 822
The same effect can be obtained by making the central part of the pulp body 821h protrude toward the pulp body 821h, forming an annular groove 822c on the outer periphery of the central part, and storing the spring 823 in the annular groove 822c.

In each of the embodiments described above, the present invention is applied to the case of stopping fuel supply, but contrary to the above 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 is reduced and the spool 822 is displaced, thereby closing the di-annular groove 827. As a result, the fuel recirculation is immediately stopped and fuel supply to the fuel injection nozzle slope is started.

Effects of the Invention As described above, according to the present invention, it is possible to obtain a fuel control device that is simple, compact, and has excellent responsiveness.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the present invention, and FIG.
) (b) (C) are the fuel IJ IJ- in the first embodiment
FIG. 3 is a cross-sectional view showing the second embodiment, and FIG. 4 is a cross-sectional view showing main parts of the third embodiment. FIG. 5 is a sectional view showing the main parts of the fourth embodiment. l...High pressure pump, 2...Fuel injection nozzle. 7...Tank, 8...Fuel control device, 81
...Solenoid valve (electrically operated valve) 812b...Small hole (first relief boat) 82I...Cylinder member,
822...Suguru. 822b... End face (pressure chamber side end face) 827... Annular groove (second relief port). Patent Applicant Japan Auto Parts Research Institute Co., Ltd. Patent Attorney Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Kyo Nakayama Akira Yamaguchi Figure 4 Figure 5 439-

Claims (1)

[Claims] 1. A cylindrical cylinder member that communicates with a pressure chamber in a high-pressure pump that pressure-feeds fuel to a fuel injection nozzle and has first and second relief ports for returning fuel to a tank; , 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 port, and has an outer circumferential side that opens and closes the second relief port; and an electrically operated valve that opens and closes the first relief port, and when the electrically operated valve opens the first relief port, a pressure difference is generated in the vicinity of the spool, and the spool is displaced. The fuel control device is characterized in that the second relief port is opened to allow fuel to flow back, and fuel supply to the fuel injection nozzle is stopped. 2. The second relief port is formed by aligning an edge with the pressure chamber side end surface of the spool at a position where the spool contacts the pressure chamber side end surface in the cylinder member. The fuel control device according to scope 1. 3. The fuel control device according to claim 1, wherein a portion of the cylinder member is fitted into the spool internal hole and the first relief port is formed within the spool internal hole. 4. The fuel control device according to claim 1, wherein a portion of the pressure chamber side end surface of the cylinder member that contacts the spool is molded separately from other portions of the cylinder member. 5. The fuel control device according to claim 1, wherein the second relief port communicates with the first relief port via a passage bored in a cage non-contact housing the cylinder member. 6. 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 ports that allow the fuel to flow back into the tank; a spool that is slidably fitted into the cylinder member, has an internal hole that constantly communicates the pressure chamber and the first relief port, and has an outer circumferential side that opens and closes the second relief port; and a spool that opens and closes the first relief port. and an electrically operated valve that performs the above-mentioned t1! By blocking the j-7 boat, the pressure difference in the vicinity of the spool decreases, causing the spool to be displaced, thereby blocking the second relief port, stopping fuel reflux, and reducing the flow of fuel to the fuel injection nozzle. A fuel control device characterized in that fuel supply is started. 7. The second relief port is formed by matching the edge of the spool with the pressure chamber side end surface of the spool at a position where the spool contacts the pressure chamber side end surface of the cylinder member. The fuel control device according to scope 6. 8. The fuel control device according to claim 6, wherein a portion of the cylinder member is fitted into the spool internal hole and the first relief port is formed within the internal hole. 9. The fuel control device according to claim 6, wherein a portion of the pressure chamber side end surface of the cylinder member that contacts the spool in vortex contact is formed separately from other portions of the cylinder member. 7. The fuel control device according to claim 6, wherein the second relief port 51o communicates with the first relief port via a passage bored in a casing housing the cylinder member.