JPH11270433A - Variable discharge high pressure pump - Google Patents

Abstract

(57) [Problem] To provide a variable discharge high pressure pump capable of quickly opening an electromagnetic valve, sufficiently supplying fuel to a pump chamber, and improving lubrication of a sliding portion. obtain. SOLUTION: A cylinder portion 14a and a fuel intake passage 4 are provided.
2, a cylinder 14 formed with the fuel pressurizing member 15,
It has a pump chamber 16 and an electromagnetic valve 30, and the electromagnetic valve 30
When the seat portion 37 formed in the fuel suction passage 31 is energized, the valve body 38 closes when the energization is performed, whereby high-pressure fuel in the pump chamber 16 is pumped into the common rail, and the fuel discharge amount is controlled according to the energization period. The body 38 is an external valve that closes the seat 37 by receiving the high-pressure fuel pressure in the pump chamber 16 as a pressing force in the valve closing direction when the valve is closed, and the cylinder 14 and the fuel pressurizing member 15 At the top dead center of the member 15, communication passages 71 and 7 that communicate the pump chamber 16 and the fuel suction passage 19.
2, 73, 74.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable discharge high pressure pump used for a common rail type fuel injection device, and more particularly to a variable discharge high pressure pump capable of improving efficiency.

[0002]

2. Description of the Related Art FIG. 5 is a configuration diagram of a common rail type fuel injection device disclosed in, for example, JP-A-64-73166. In FIG. 5, an injector 2 is disposed in the engine 1 with respect to a combustion chamber of each cylinder, and fuel is injected from the injector 2 to the engine 1 by an injection control solenoid valve 3.
It is controlled by N-OFF. The injector 2 is connected to a common high-pressure accumulating pipe, a so-called common rail 4, common to each cylinder, and the fuel in the common rail 4 is injected from the injector 2 to the engine 1 while the injection control solenoid valve 3 is opened. Therefore, it is necessary to continuously accumulate a high predetermined pressure corresponding to the fuel injection pressure on the common rail 4. For this purpose, the variable discharge high pressure pump 100 is connected via the supply pipe 5 and the discharge valve 20.

A high-pressure pump 100 pressurizes fuel sucked from a fuel tank 8 through a low-pressure supply pump 9 to a high pressure.
The fuel in the common rail 4 is controlled and maintained at a high pressure. Electronic control unit ECU4 for controlling this system
For 0, for example, information on the number of revolutions and the load is input from the engine speed sensor 41 and the load sensor 42, and the optimum injection timing and injection amount (= Injection period)
U40 outputs a control signal to the injection amount control solenoid valve 3. At the same time, the ECU 40 outputs a control signal to the high-pressure pump 100 so that the injection pressure becomes an optimum value according to the load and the rotation speed.

Further, a pressure sensor 43 for detecting the common rail pressure is provided on the common rail 4, and the discharge amount of the high-pressure pump 100 is adjusted so that the signal of the pressure sensor 43 becomes an optimum value set in advance according to the load and the number of revolutions. Controlled.

FIG. 6 is a sectional view of a conventional variable discharge high pressure pump. FIG. 7 is a main part configuration diagram of a common rail type fuel injection device using a conventional variable discharge high pressure pump. FIG.
In the figure, reference numeral 10 denotes a pump housing of the high-pressure pump 100, and a cam chamber 11 is formed at a lower end. A cam shaft 12 that rotates at half the speed of the engine is inserted into the cam chamber 11.
Are formed. The cam 13 performs a rising stroke twice per rotation of the camshaft 12, that is, forms a double mountain cam,
As shown in FIG. 7, the phases of the cams 13 depending on the cam lift angle are different from each other by the 120-degree pump rotation angle.

In the pump housing 10, the cylinder 1
4 is attached. The cylinder 14 has a cylindrical cylinder portion 14a formed along the central axis. A cylindrical plunger 15 is provided in the cylinder portion 14a.
Are reciprocally and slidably fitted. Plunger 1
The pump chamber 16 is formed by the upper end surface of the cylinder 5 and the inner peripheral surface of the cylinder portion 14a. The cylinder 14 has the pump chamber 1
The feed chamber 17 and the pump chamber 1 at a position above the feed hole 17 in the figure
A discharge hole 18 communicating with the nozzle 6 is formed. The feed hole 17 communicates with a fuel reservoir 19 formed between the cylinder 14 and the pump housing 10. The fuel reservoir 19 is supplied with low-pressure fuel from the low-pressure supply pump 9 via an introduction pipe 28. I have.

[0007] A discharge valve 20 is attached to the cylinder 14, and the discharge valve 20 communicates with the pump chamber 16 through a discharge hole 18. The fuel pressurized in the pump chamber 16 pushes and hears the valve body 21 of the discharge valve 20 against the urging force of the return spring 22, and pressurized high-pressure fuel is discharged through the discharge port body 23 into the common rail 4. To pump.

The lower end of the plunger 15 is connected to a valve seat 24, which is pressed against a slider 26 by a return spring 25. The slider 26 has a cam roller 27 which is in sliding contact with the cam 13. Accordingly, when the cam 13 is rotated by the rotation of the cam 12 shaft, the plunger 15 is reciprocally slid through the cam roller 27 and the valve seat 24. The plunger 15
Is determined by the height difference of the cam 13. Therefore, when the plunger 15 reciprocates in the cylinder 14, the outer peripheral surface of the plunger 15 opens and closes the feed hole 17, and when the outer peripheral surface of the plunger 15 does not close the feed hole 17, the feed hole 17 is closed.
The fuel on the low pressure side is supplied to the pump chamber 16 via.

An electromagnetic valve 30 is screwed and fixed to the upper portion of the cylinder 14 in FIG. 6 at a position facing the upper end surface of the plunger 15. As shown in FIG. 8, the solenoid valve 30 has a body 32 in which one end is open to the pump chamber 16 and the other end is formed with a low-pressure passage 31 communicating with the low-pressure side. Armature 36 which is sucked upward in FIG. 6 against the urging force of spring 35
And the pump chamber 1 moves integrally with the armature 36 and
6 has a mushroom-shaped valve body 38 which is an externally opened valve that communicates and shuts off the low pressure passage 31 by being in close contact with a seat portion 37 formed at the opening to the opening 6.
6 is received as a pressing force in the valve closing direction.

The solenoid valve 30 is energized at a predetermined timing after the outer peripheral surface of the plunger 15 closes the feed hole 17, so that the valve body 38
The solenoid valve is a pre-stroke control type solenoid valve that sets the pressure start timing of the plunger 15 while sitting on the solenoid valve. The discharge amount to the common rail 4 is changed by controlling the timing of energizing the solenoid valve 30. The low-pressure passage 31 communicates with the fuel reservoir 19 via the gallery 41 and the passage 42. When the plunger 15 descends with the valve body 38 opened, the low-pressure passage 31 is connected to the low-pressure passage 31 through the low-pressure passage 31. Fuel is supplied to the pump chamber 16.

In order to control the solenoid valve 30, as shown in FIG. 7, a rotating disk 51 having a number (six) of protrusions corresponding to the number of engine cylinders is mounted coaxially with the camshaft 12, and the protrusions are mounted on the protrusions. A cam angle sensor 50, which is a known electromagnetic big-up, is disposed opposite the sensor, and a signal is sent to the ECU 40 every time the protrusion passes near the sensor. here,
The mounting phase of the protruding disk 51 is determined so as to approach the sensor 50 at a rotation phase near each bottom dead center of the cam 13.

Further, the cam shaft 12 has a pair of disks 61.
And a cylinder discriminating sensor 62 are also coaxially mounted. Only one protrusion is formed on the disk 61, so that the ECU 40 receives one signal from the sensor 62 per one rotation of the pump. The ECU 40 can accurately determine and obtain the bottom dead center signal of the pump specific cylinder from the signal of the cylinder determination sensor 62 and the signal of the cam angle sensor 50. In FIG. 7, the cam 13 is illustrated by rotating the disk 51, the plunger 15, the cylinder 14, and the like by 90 °.

Next, the operation will be described. In FIG. 6, a plunger 15 reciprocated with the rotation of the camshaft 12 includes:
When the plunger 15 opens the feed hole 17 when descending, fuel is introduced into the pump chamber 16 through the feed hole 17, and when the outer peripheral surface of the plunger 15 closes the feed hole 17 when ascending, the plunger 15 starts pumping. An attempt is made to pressurize the fuel in the chamber 16. However, at this time, since the solenoid valve 30 is not energized, the valve body 38 of the solenoid valve 30 is open. Therefore, the fuel in the pump chamber 16 overflows through the low-pressure passage 31, the gallery 41, and the passage 42 in order and is not pressurized.

When a control pulse is sent to the solenoid valve 30 during the overflow of the fuel in the pump chamber 16, the valve body 38 sits on the seat 37 and the low-pressure passage 31 is closed. Therefore, the pressurization of the fuel in the pump chamber 16 by the plunger 15 is started, and when the fuel pressure in the pump chamber 16 overcomes the urging force of the spring 22 of the discharge valve 20, the fuel pressure-fed through the discharge hole 18 becomes a valve body. 21 is pushed open and discharged through the discharge port body 23 into the common rail 4.

Next, the operation of the common rail type fuel injection device will be described with reference to FIGS. FIG. 9 is a time chart showing the operation of the pump over approximately one rotation of the pump, that is, over 360 ° cam rotation. 9A shows a signal from the cylinder discriminating sensor 62 in FIG. 7, and FIG.
Indicates a signal from the cam angle sensor 50. From the signals from both sensors, the ECU 40 can know the specific cam phase of the pump specific cylinder. (C), (E) and (G) show the cams 13 respectively.
a, 13b, and 13c, the three cylinders shown in FIG.
With a double cam configuration, six pressure feeds corresponding to the number of engine cylinders are performed during one rotation of the camshaft 12.

(D), (F) and (H) show the solenoid valves 30a. 30b. A control signal to the solenoid valve 30a, 30c is provided from the ECU 40 at a predetermined timing T (or cam angle) from the cam angle signal after the outer peripheral surface of the plunger 15 closes the feed hole 17.
Control signals are sent to b and 30c, and this control signal is interrupted by the next cam angle signal. Therefore, while the control signal is being sent to the solenoid valve 30, the solenoid valve 30 is closed, and the fuel in the pump chamber 16 pressurized by the plunger 15 during the cam lift H after the valve is closed is not shown. 7 flows into the common rail 4 via the discharge valve 20 corresponding to the hatched portion, and is accumulated in the common rail 4.

Since the valve body 38 of the solenoid valve 30 receives the fuel pressure in the pump chamber 16 as a pressing force in the valve closing direction, the valve body 38 is seated on the seat 37 with high accuracy. If the valve body 38 is pressurized, the valve body 38 is pressed in the valve closing direction by the fuel pressure in the pump chamber 16 due to the pressurizing process of the plunger 15 in a state where the valve body 38 is seated on the seat portion 37, and excellent sealing performance is maintained. Can be.

In the above operation, the solenoid valves 30a,
If the energization timing T to 30b, 30c is controlled according to the engine load (detected by the load sensor 42), the engine speed (detected by the speed sensor 41) or the common rail pressure (detected by the pressure sensor 43), It is possible to control the amount of fuel required to generate and maintain a target common rail pressure, and to achieve a desired common rail pressure. That is, if the energization timing T is controlled to be long, the communication time between the pump chamber 16 and the low-pressure passage 31 becomes long, so that
The so-called pre-stroke time becomes longer, and the fuel discharge amount decreases. Conversely, if the energization timing T is controlled to be short,
Since the communication between the pump chamber 16 and the low-pressure passage 31 is shortened,
The blur stroke time becomes shorter, and the fuel discharge amount increases.

In the variable discharge high pressure pump having such a configuration, the valve body 38 of the solenoid valve 30 is a mushroom-shaped externally opened valve that receives the fuel pressure in the pump chamber 16 as a pressing force in the valve closing direction. In a state where the valve body 38 is seated on the seat portion 37, the valve body 38 is pressed in the valve closing direction by the fuel pressure in the pump chamber 16 due to the pressurizing process of the plunger 15, thereby maintaining excellent sealing properties.

[0020]

In order to supply fuel to the pump chamber 16 in the conventional apparatus, first, after the cam 13 has passed the top dead center and the plunger 15 has been lowered, when the valve body 38 opens, the low pressure passage 31 is opened. The feed hole 1 is supplied to the pump chamber 16 and the plunger 15 further descends to feed hole 1.
Pump chamber 1 from feed hole 17 when descending from 7
6.

In the opening of the solenoid valve 30, when the pressure in the pump chamber 16 falls below the urging force of the spring 35 after the solenoid valve 30 is turned off, the valve opening is started.
Therefore, if the decrease in the pressure in the pump chamber 16 is delayed due to, for example, a blow-back of the fuel from the discharge valve 20 after the fuel is discharged, the opening timing of the solenoid valve 30 is delayed. Then, when the opening timing of the solenoid valve 30 is delayed, the amount of fuel supplied to the pump chamber 16 decreases, the discharge amount of the high-pressure pump 100 decreases, and the efficiency of the high-pressure pump 100 deteriorates. Further, since the valve body 38 of the solenoid valve 30 is a mushroom-shaped external valve that receives the fuel pressure in the pump chamber 16 as a pressing force in the valve closing direction, the valve opening property is further deteriorated, which is a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and can open a solenoid valve quickly, sufficiently supply fuel to a pump chamber, and improve efficiency. It is another object of the present invention to provide a variable discharge high pressure pump capable of improving the lubricity of a cylinder and a plunger.

[0023]

According to a first aspect of the present invention, there is provided a variable discharge high-pressure pump according to claim 1, wherein the cylinder has a cylindrical portion, a fuel intake passage and a fuel discharge passage formed in the cylinder portion, and a reciprocating motion in the cylinder portion. A fuel pressurizing member that is slidably fitted and driven by the engine, a pump chamber formed by the cylinder portion and the fuel pressurizing member, and is provided fixed to the cylinder so as to face the pump chamber. The solenoid valve has a valve body that closes when energizing a seat portion formed in the fuel suction passage, thereby pumping high-pressure fuel in the pump chamber into a common rail in which high-pressure fuel is stored. Controlling the amount of fuel discharged to the common rail in accordance with the energization period, the valve body of the solenoid valve has a surface facing the pump chamber, which presses the high-pressure fuel pressure in the pump chamber in the valve closing direction when the valve is closed. Receiving a outer open valve which closes the seat portion as in the cylinder and fuel pressure member,
A communication passage that connects the pump chamber and the fuel suction passage is formed immediately before or at the top dead center of the fuel pressurizing member.

In the variable discharge high pressure pump according to the second aspect, the communication passage is formed in the cylinder, and the first communication passage connects the first opening formed in the sliding surface of the cylinder portion to the fuel suction passage. A second passage formed in the sliding surface of the fuel pressurizing member which is formed in the fuel pressurizing member and which is communicated with the first opening when the fuel pressurizing member is at the top dead center or a position immediately before the top dead center. And a second communication passage communicating the pump chamber with the opening.

According to the third aspect of the present invention, the first opening is a spill groove formed annularly on the sliding surface of the cylinder portion.

In the variable discharge high pressure pump according to the fourth aspect, the second opening is an annular spill groove formed on the sliding surface of the fuel pressurizing member.

In the variable discharge high pressure pump according to the fifth aspect, the communication passage is further formed in the cylinder, and the third passage communicating the third opening formed in the sliding surface of the cylinder portion with the fuel suction passage. The communication passage and the fuel pressurizing member are formed on a sliding surface of the fuel pressurizing member that communicates with the third opening when the fuel pressurizing member is at the top dead center or a position immediately before the top dead center. 4 and a fourth communication passage communicating the pump chamber with the opening.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a sectional view of a variable discharge high pressure pump according to the present invention. FIG. 2 is a main part configuration diagram of a common rail fuel injection device using the variable discharge high pressure pump of the present invention. In FIG. 1, reference numeral 10 denotes a variable discharge high pressure pump 200 pump housing,
A cam chamber 11 is formed at the lower end. A cam shaft 12 that rotates at half the speed of the engine is inserted into the cam chamber 11, and a cam 13 is formed on the cam shaft 12. The cam 13 makes a two-degree ascending stroke per rotation of the camshaft 12, that is, forms a two-peak cam. As shown in FIG. The corners are different from each other.

In the pump housing 10, the cylinder 1
4 is attached. The cylinder 14 has a cylindrical cylinder portion 14a formed along the central axis. A cylindrical plunger 15, which is a fuel pressurizing member, is reciprocally and slidably fitted in the cylinder portion 14a. The upper part of the plunger 15 and the cylinder part 14
The pump chamber 16 is formed by the inner peripheral surface of a. A discharge hole 18 is formed in the cylinder 14 as a fuel discharge passage communicating with the pump chamber 16 as in the related art. A fuel reservoir 19 is formed in an annular shape on a connection surface between the cylinder 14 and the pump housing 10. This fuel pool 1
9 is supplied with low-pressure fuel from a low-pressure supply pump 9 via an introduction pipe 28.

An annular spill groove 71, which is a first opening, is formed at a predetermined position on the sliding surface of the cylinder portion 14a. Further, the cylinder 14 has a spill groove 71
A first communication path 72 that communicates with the fuel reservoir 19 is formed. On the other hand, an opening 73 as a second opening is formed at a predetermined position on the sliding surface of the plunger 15.
Further, the plunger 15 has a second
Communication path 74 is formed. The second communication path 74 is
The opening 73 communicates with the pump chamber 16. Opening 73
Are provided at two locations facing each other so that the high pressure of the pump chamber 16 does not act on the plunger 15 in an uneven manner. Further, the fuel in the pump chamber 16 is supplied to the cylinder portion 14a.
Opening 7 so as not to leak from the gap between
3 is formed as small as possible. FIG. 1 shows a state where the plunger 15 is located at the top dead center. The opening 73 communicates with the spill groove 71 when the plunger 15 has just reached the top dead center.

A discharge valve 20 is attached to the cylinder 14, and the discharge valve 20 communicates with the pump chamber 16 through a discharge hole 18. The fuel pressurized in the pump chamber 16 pushes and hears the valve body 21 of the discharge valve 20 against the urging force of the return spring 22, and pressurized high-pressure fuel is discharged through the discharge port body 23 into the common rail 4. To pump.

The lower end of the plunger 15 is connected to a valve seat 24, which is pressed against a slider 26 by a return spring 25. The slider 26 has a cam roller 27 which is in sliding contact with the cam 13. Accordingly, when the cam 13 is rotated by the rotation of the cam 12 shaft, the plunger 15 is reciprocally slid through the cam roller 27 and the valve seat 24. The plunger 15
Is determined by the height difference of the cam 13.

An electromagnetic valve 30 is screwed and fixed to the upper part of the cylinder 14 in FIG. 1 so as to face the upper end surface of the plunger 15. The solenoid valve 30 has a low pressure passage 31 having one end opened to the pump chamber 16 and the other end communicating with the low pressure side, as in the prior art, and a magnetic force of a solenoid 34 when energizing a lead wire (not shown). Armature 3 sucked upward in FIG. 1 against the urging force of spring 35
6 and a mushroom-shaped valve body 38 which is an externally-opening valve which is moved integrally with the armature 36 and is in close contact with a seat portion 37 formed at the opening to the pump chamber 16 to communicate and shut off the low-pressure passage 31. The valve body 38 receives the fuel pressure in the pump chamber 16 as a pressing force in the valve closing direction.

The low-pressure passage 31 communicates with the fuel reservoir 19 via a gallery 41 and a passage 42.
When the plunger 15 descends with the valve 8 opened,
The low-pressure side fuel is supplied to the pump chamber 16 via the low-pressure passage 31. That is, the low-pressure passage 31, the gallery 41,
The passage 42 and the fuel reservoir 19 constitute a fuel suction passage for supplying fuel to the pump chamber 16. Solenoid valve 30
When the plunger 15 is raised, power is supplied at a predetermined timing, and the valve body 38 is seated on the seat portion 37 to set the pressure start timing of the plunger 15. That is, the pressurization start timing is set by closing the fuel intake passage at a predetermined timing. The pressurized high-pressure fuel is pressure-fed into the common rail 4 through the outlet 23 as described above. The discharge amount to the common rail 4 is changed by controlling the timing of energizing the solenoid valve 30.

In order to control the solenoid valve 30, as shown in FIG. 2, a rotating disk 51 having a number of projections (six) corresponding to the number of engine cylinders is mounted coaxially with the camshaft 12, and the projections are mounted on the projections. A cam angle sensor 50, which is a known electromagnetic big-up, is disposed opposite the sensor, and a signal is sent to the ECU 40 every time the protrusion passes near the sensor. here,
The mounting phase of the protruding disk 51 is determined so as to approach the sensor 50 at a rotation phase near each bottom dead center of the cam 13.

Further, the camshaft 12 has a pair of disks 61
And a cylinder discriminating sensor 62 are also coaxially mounted. Only one protrusion is formed on the disk 61, so that the ECU 40 receives one signal from the sensor 62 per one rotation of the pump. The ECU 40 can accurately determine and obtain the bottom dead center signal of the pump specific cylinder from the signal of the cylinder determination sensor 62 and the signal of the cam angle sensor 50. In FIG. 2, the cam 13 is illustrated by rotating the disk 51, the plunger 15, the cylinder 14, and the like by 90 °.

Next, the operation will be described. In FIG. 1, when the plunger 15 descends, the valve body 38 of the solenoid valve 30 is open. Therefore, as the plunger 15 descends,
Fuel is supplied into the pump chamber 16 through the fuel reservoir 19, the passage 42, the gallery 41, and the low-pressure passage 31.
On the other hand, when the plunger 15 rises past the bottom dead center,
The plunger 15 attempts to pressurize the fuel in the pump chamber 16, but at this time, the solenoid valve 30 is not energized, and the valve body 38 of the solenoid valve 30 is open.
The fuel inside flows through the low-pressure passage 31, the gallery 41, and the passage 42 in order, and is not pressurized.

When a control pulse is sent to the solenoid valve 30 during the fuel overflow in the pump chamber 16, the valve body 38 sits on the seat portion 37, and the low-pressure passage 31 is closed. Then, the pressurization of the fuel in the pump chamber 16 by the plunger 15 is started, and when the fuel pressure in the pump chamber 16 overcomes the urging force of the spring 22 of the valve body 21, the fuel pumped through the discharge hole 18 is discharged. 20 is pushed open and discharged through the discharge port body 23 into the common rail 4. When the plunger 15 reaches the top dead center, the high-pressure fuel in the pump chamber 16 quickly moves from the first communication path 72 to the fuel reservoir 19 through the second communication path 74, and the pressure in the pump chamber 16 is reduced. Go down. When the solenoid valve 30 is turned off, the spring 35
The valve body 38 is quickly opened by the urging force of (1), and the fuel is supplied to the pump chamber 16 as the plunger 15 moves down.

In the variable discharge high pressure pump having such a configuration, the cylinder 14 and the plunger 15 have a communication passage connecting the pump chamber 16 and the fuel reservoir 19 at a position where the plunger 15 reaches the top dead center. Since the valve body 38 of the electromagnetic valve 30 is quickly opened and the plunger 15 is lowered, the suction operation to the pump chamber 16 is started immediately. And the efficiency of the high-pressure pump 200 is improved.
The communication passage is formed between the spill groove 71 formed on the sliding surface of the cylinder portion 14a and the spill groove 71 and the fuel reservoir 19.
And a second communication passage 74 communicating the pump chamber 16 with the opening 73 formed in the plunger 15 and the pump chamber 16. The communication start timing between the second communication passage 74 and the second communication passage 74 can be made accurate, and the valve opening timing of the valve body 38 is assured, so that the control of the high-pressure pump 200 is correct and the discharge amount is accurate. . And further, the cylinder part 14a
Since the spill groove 71 is formed on the sliding surface of, the lubrication of the cylinder 14 and the plunger 15 is improved and seizure is prevented.

In this embodiment, the opening 73 is used.
When the plunger 15 reaches the top dead center, the spill groove 71
However, if there is a margin in the maximum discharge amount of the pump, the connection may be made at a position slightly before the top dead center. Further, the openings 73 are provided at two locations facing each other, but the number of openings 73 is not limited to two, and more openings 73 may be formed at equal intervals in the circumferential direction.

Embodiment 2 FIG. 3 is a main part configuration diagram of a common rail type fuel injection device using another example of the variable discharge amount high pressure pump of the present invention. In the variable discharge high-pressure pump 300 of the present embodiment, an opening 75 as a first opening is formed at a predetermined position on the sliding surface of the cylinder portion 14a. Further, the cylinder 14 has a first communication path 7 for communicating the opening 75 with a fuel reservoir 19 (not shown).
2 are formed. On the other hand, on the sliding surface of the plunger 15, an annular spill groove 76 as a second opening is provided at a predetermined position.
Are formed. And furthermore, the plunger 15
A second communication path 74 is formed along the central axis. The second communication passage 74 communicates the spill groove 76 with the pump chamber 16. The spill groove 76 communicates with the opening 75 when the plunger 15 has just reached the top dead center. Other configurations are the same as those of the first embodiment.

In the variable discharge high pressure pump having such a configuration, the same effect as that of the first embodiment can be obtained, and the spill groove 76 is formed on the sliding surface on the plunger 15 side, so that processing is easy. The cost can be reduced.

Embodiment 3 FIG. 4 is a sectional view showing another example of the variable discharge high pressure pump according to the present invention. In the variable discharge high-pressure pump 400 of the present embodiment, first, a spill groove 77 as a third opening is formed on the cam 13 side of the spill groove 71 formed on the sliding surface of the cylinder 14. The spill groove 77 is communicated with the fuel reservoir 19 by a third communication passage 78. On the other hand, plunger 15
Further, an opening 79 as a fourth opening is formed on the cam 13 side of the opening 73 on the sliding surface of FIG. The plunger 15 has
A fourth communication passage 80 is formed along the central axis. The fourth communication path 80 communicates the opening 79 with the first communication path 72. The openings 79 are provided at two locations facing each other so that the high pressure of the pump chamber 16 does not act on the plunger 15 in an uneven manner. FIG. 1 shows a state where the plunger 15 is located at the top dead center. The opening 79 is
When the plunger 15 has just reached the top dead center, it communicates with the spill groove 77. Other configurations are the same as those of the first embodiment.

The variable discharge high-pressure pump having the above-described structure further includes one communication path for communicating the pump chamber 16 and the fuel reservoir 19, so that the valve body 38 of the solenoid valve 30 is provided.
Is more quickly opened, and the suction operation into the pump chamber 16 is further improved. In addition, 2 of the sliding surface of the cylinder portion 14a
Since the spill groove 71 and the spill groove 77 are formed at the locations, the lubricity of the cylinder 14 and the plunger 15 can be further improved.

[0045]

According to the first aspect of the present invention, there is provided a variable discharge high pressure pump, comprising: a cylindrical cylinder portion; a cylinder having a fuel suction passage and a fuel discharge passage formed therein;
A fuel pressurizing member that is reciprocally and slidably fitted in the cylinder portion and is driven by the engine, a pump chamber formed by the cylinder portion and the fuel pressurizing member, and fixed to the cylinder so as to face the pump chamber. A high-pressure fuel in the pump chamber is stored in the pump chamber by closing the valve body when the seat portion formed in the fuel suction passage is energized. The solenoid valve is pressure-fed into the common rail and controls the amount of fuel discharged to the common rail according to the energization period. The valve body of the solenoid valve faces the pump chamber when the high-pressure fuel pressure in the pump chamber closes when the valve is closed. An external valve that closes the seat portion by receiving the pressing force in the valve direction,
The cylinder and the fuel pressurizing member are formed with a communication passage connecting the pump chamber and the fuel suction passage immediately before or at the top dead center of the fuel pressurizing member. Therefore, when the fuel pressurizing member reaches the top dead center, the high pressure in the pump chamber is released to the fuel suction passage, the valve body can be opened quickly, and the suction operation into the pump chamber is started immediately, so that the efficiency of the pump is improved. Will be better.

In the variable discharge high pressure pump according to the second aspect, the communication passage is formed in the cylinder, and the first communication passage connects the first opening formed in the sliding surface of the cylinder portion to the fuel suction passage. A second passage formed in the sliding surface of the fuel pressurizing member which is formed in the fuel pressurizing member and which is communicated with the first opening when the fuel pressurizing member is at the top dead center or a position immediately before the top dead center. And a second communication passage communicating the pump chamber with the opening. Therefore, the communication start timing of the first communication path and the second communication path can be made accurate, and the discharge amount of the high-pressure pump can be made accurate.

According to the third aspect of the present invention, the first opening is a spill groove formed in an annular shape on the sliding surface of the cylinder portion. Therefore, the lubricity of the cylinder and the fuel pressurizing member can be improved, and seizure can be prevented.

In the variable discharge high pressure pump according to the fourth aspect, the second opening is a spill groove formed annularly on the sliding surface of the fuel pressurizing member. Therefore, processing becomes easy and cost can be reduced.

In the variable discharge high pressure pump according to the fifth aspect, the communication passage is further formed in the cylinder, and the third passage communicating the third opening formed in the sliding surface of the cylinder portion with the fuel suction passage. The communication passage and the fuel pressurizing member are formed on a sliding surface of the fuel pressurizing member that communicates with the third opening when the fuel pressurizing member is at the top dead center or a position immediately before the top dead center. 4 and a fourth communication passage communicating the pump chamber with the opening. Therefore, the high pressure in the pump chamber is more easily released to the fuel suction passage, and the efficiency of the pump is further improved. Further, the lubricating properties of the cylinder and the fuel pressurizing member can be further improved, and seizure is prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a variable discharge high pressure pump according to the present invention.

FIG. 2 is a main part configuration diagram of a common rail type fuel injection device using the variable discharge amount high pressure pump of the present invention.

FIG. 3 is a main part configuration diagram of a common rail type fuel injection device using another example of the variable discharge amount high pressure pump of the present invention.

FIG. 4 is a sectional view showing another example of the variable discharge high pressure pump according to the present invention.

FIG. 5 is a configuration diagram of a common rail type fuel injection device.

FIG. 6 is a sectional view of a conventional variable discharge high pressure pump.

FIG. 7 is a main part configuration diagram of a conventional common rail type fuel injection device using a variable discharge amount high pressure pump.

FIG. 8 is a sectional view showing details of a solenoid valve.

FIG. 9 shows the state of operation of the pump for approximately one rotation of the pump.
That is, it is a time chart shown over a 360 ° cam rotation.

[Explanation of symbols]

14 cylinder, 14a cylinder portion, 15 plunger (fuel pressurizing member), 16 pump chamber, 18 discharge hole (fuel discharge passage), 19 fuel reservoir (fuel suction passage), 30 solenoid valve, 31 low pressure passage (fuel suction passage) , 37 seat portion, 38 valve body, 41 gallery (fuel intake passage), 42 passage (fuel intake passage), 71
Spill groove (first opening), 72 first communication path, 73
Opening (second opening), 74 second communication path, 75 opening (first opening), 76 spill groove (second opening), 7
7 spill groove (third opening), 78 third communication path, 7
9 opening (fourth opening), 80 fourth communication path.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hidekazu Satake 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Hiroyuki Akita 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Rishi Electric Co., Ltd. (72) Inventor Koji Kawamura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Toshinori Tanaka 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Inside (72) Inventor Katsunori Tanaka 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (5)

[Claims] 1. A cylinder formed with a cylindrical cylinder portion, a fuel intake passage and a fuel discharge passage communicating with the cylinder portion, and a fuel reciprocally and slidably fitted into the cylinder portion and driven by an engine. A pressurizing member, a pump chamber formed by the cylinder portion and the fuel pressurizing member, and an electromagnetic valve fixed to the cylinder so as to face the pump chamber; The high pressure fuel in the pump chamber is pumped into the common rail in which the high pressure fuel is stored by closing the valve body when the seat portion formed in the fuel suction passage is energized, and the valve is closed according to the energization period. A valve for controlling the amount of fuel discharged to a common rail, wherein a surface of the valve body of the solenoid valve facing the pump chamber has a high-pressure fuel pressure in the pump chamber as a pressing force in a valve closing direction when the valve is closed. An outer opening valve for receiving and closing the seat portion, wherein the cylinder and the fuel pressurizing member are provided with the pump chamber and the fuel suction passage immediately before or at the top dead center of the fuel pressurizing member. A high-pressure pump with a variable discharge amount, wherein a communication passage for communicating with the pump is formed. A first opening formed in the cylinder and communicating with a first opening formed in a sliding surface of the cylinder portion and the fuel suction passage;
And a sliding surface of the fuel pressurizing member formed in the fuel pressurizing member and communicating with the first opening when the fuel pressurizing member is at a top dead center or a position immediately before the top dead center. 2. The variable discharge high pressure pump according to claim 1, further comprising a second communication passage communicating the pump chamber with the second opening formed in the pump chamber. 3. The variable discharge high pressure pump according to claim 2, wherein said first opening is a spill groove formed annularly on a sliding surface of said cylinder portion. 4. The variable discharge high pressure pump according to claim 2, wherein said second opening is a spill groove formed annularly on a sliding surface of said fuel pressurizing member. 5. A third communication passage formed in the cylinder, the third communication passage communicating a third opening formed in a sliding surface of the cylinder portion with the fuel suction passage, and the fuel passage; A fourth member formed on the sliding surface of the fuel pressurizing member which is formed on the pressurizing member and communicates with the third opening when the fuel pressurizing member is at the top dead center or a position immediately before the top dead center. 3. The variable discharge high pressure pump according to claim 2, further comprising a fourth communication passage communicating the opening with the pump chamber.