JPH0828386A - Fluid pressure generator - Google Patents

Abstract

PURPOSE:To provide a fluid pressure generator by which damage of a piston or the like can be prevented and additional liquid can be accurately delivered. CONSTITUTION:The whole area of end surfaces 3a and 3b of a piston 3 is formed as a plane, and the whole area of a piston working face 3a except an opening part of a communicating passage 10 of a piston working face of a regulating body 6 is formed as a plane, and a throttle valve 14 is arranged in the middle of a supply port 12a to supply oil pressure to an oil pressure chamber 4. Therefore, when the oil pressure is supplied to the oil pressure chamber 4, the piston 3 is driven to the pressure chamber 2 side in response to this, and since additional liquid is delivered from the pressure chamber 2 at the same time, the delivery timing of the additional liquid becomes accurate, so that a proper quantity of additional liquid can be delivered according to an operating condition of a diesel engine. Driving speed of the piston 3 is restrained by the throttle valve 14, and damage of both by collision between the piston 3 and the regulating body 6 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pressure generator for supplying an additional liquid together with a main fuel to a fuel injection nozzle in a diesel engine or the like.

[0002]

2. Description of the Related Art In recent years, diesel engines used in power generators and the like have a main purpose of reducing nitrogen oxides (hereinafter referred to as NOx) which are harmful components in exhaust gas. It has been proposed to inject additional liquid into the combustion chamber of a diesel engine. In this case, water is generally used as the additional liquid for the purpose of reducing NOx.

In order to supply the additional liquid together with the main fuel to the combustion chamber of the engine for the purpose of reducing Nox, as shown in FIG. 5, the combustion chamber 20a of the cylinder 20 of the multi-cylinder type diesel engine is supplied from the fuel injection pump 21. The additional liquid supply path 23 led from the water pressure pump 17 is connected in the middle of the main fuel supply path 19 to the fuel injection nozzle 22 provided in the fuel injection nozzle 22, and the water is supplied from the water pressure pump 17 in the middle of the additional liquid supply path 23. The variable volume pressure chamber 2 into which water as the added liquid flows, and the reciprocating piston 24 that discharges the water flowing into the pressure chamber 2 toward the main fuel supply path 19.
And a hydraulic pressure generator 25 including the hydraulic chamber 4 for supplying and discharging the hydraulic pressure that drives the piston 24.

The hydraulic pressure chamber 4 of the hydraulic pressure generator 25 is connected to a hydraulic pressure supply / discharge path 26 leading to the pump device 11. An electromagnetic valve 12 is provided in the middle of the hydraulic pressure supply / discharge path 26 to switch the hydraulic pressure supply / discharge path 26 between a supply state and a discharge state based on a control signal a from the controller 13. The controller 13 detects the top dead center of the diesel engine with a proximity switch (not shown), and operates the solenoid valve 12 based on a signal from the proximity switch.

Further, the hydraulic pressure generator 25 is provided with a variable volume mechanism 27 for changing the volume of the pressure chamber 2. The variable volume mechanism 27 includes a rod portion 2 of a regulation body 28 that is movable left and right to regulate the movement of the piston 24 to the left.
8a is connected to a screw rod 30 that is screwed into the female screw portion of the tubular body 29 fixed to the hydraulic pressure generator 25, and the screw rod 30 and the fuel rack 31 are interlocked to rotate via a bevel gear mechanism 32. It is configured to do. The fuel rack 31 rotates according to an increase / decrease in the amount of main fuel injected by the fuel injection pump 21.

According to the hydraulic pressure generator 25, the hydraulic pressure supply / discharge path 2
When the solenoid valve 12 of 6 is in the position shown in FIG. 5, that is, when the hydraulic pressure is discharged from the hydraulic chamber 4, the water sent from the hydraulic pump 17 to the additional liquid supply path 23 is As shown by an arrow x, the main fuel in the main fuel supply path 19 is passed through the check valve 18a, the supply / discharge port 34, the pressure chamber 2, and the piston 24 to the right end. Is blocked by the check valve 18b from flowing into the communication portion 18 side. In this case, since the pressure on the fuel injection pump 21 side is higher than the pressure on the hydraulic pump 17 side, water does not flow into the main fuel supply path 5 side from the check valve 18b.

On the other hand, when the solenoid valve 12 is switched from the state shown in FIG. 6 to the other position by the control signal a of the controller 13, it is operated from the hydraulic pressure supply / discharge path 44 to the hydraulic chamber 4 of the hydraulic pressure generator 24. Oil is supplied, and the oil pressure moves the piston 23 to the left end as shown in FIG.
As a result, the water that has flowed into the pressure chamber 2 passes through the check valve 18b as shown by arrows y and y and is discharged toward the main fuel supply path 19, and the fuel is injected from the fuel injection nozzle 22 into the combustion chamber of the diesel engine. 20a is injected.

When the injection amount of the main fuel injected from the fuel injection nozzle 22 changes due to the change of the operating region of the engine, the change in the injection amount is changed as shown in FIG. The illustrated fuel rack 31 rotates, and this rotation is transmitted to the screw rod 30 via the bevel gear mechanism 32, and the rotation of the screw rod 30 moves the restricting body 28 to the left or right, so that the volume of the pressure chamber 2 changes. To do. As a result, the amount of water injected from the pressure chamber 2 to the main fuel supply path 19 and then to the combustion chamber 20a increases or decreases in exact correspondence to the change in the injection amount of the main fuel.

[0009]

In the above-described hydraulic pressure generator, as shown in FIGS. 6 and 7, damage to the piston 23 at the stroke end due to collision between the piston 23 and the regulating body 28 is prevented. To this end, a convex portion 23a and a concave portion 28b are formed on the opposing end faces of both, and the convex portion 23a
Also, at the stroke end of the piston 23 in the concave portion 28b, the impact when the convex portion 23a pushes the additional liquid into the concave portion 28b can absorb the impact.
Similarly, the convex portion 2 is also formed on the end surface of the piston 23 on the hydraulic chamber side.
3b is provided, and the guide member 33 that slidably supports the piston 23 is provided with the recessed portion 33a, so that the piston 23 and the guide member 33 are prevented from being damaged by a collision between them.

However, as shown in FIGS. 4 to 7, when the signal a from the controller 13 is turned on, that is, when the hydraulic pressure is supplied from the pump device 11 to the hydraulic chamber 4 via the solenoid valve 12, the piston 23 is driven from the position of FIG. 6 and reaches a predetermined stroke amount and moves to the position of FIG. 7, but as can be seen from the fact that the polygonal line shown in FIG. , The driving speed can be suppressed.

On the contrary, when the signal a from the controller 13 is turned off, that is, when the hydraulic pressure in the hydraulic chamber 4 is discharged through the solenoid valve 12, the piston 23 is supplied to the pressure chamber 2 from the position shown in FIG. Although it is pushed back by the additional liquid to move to the position of FIG. 6, the driving speed of the piston 23 at the initial driving stage and the stroke end is suppressed as described above.

For the above reasons, the discharge timing of the additional liquid becomes inaccurate, and an appropriate amount of the additional liquid is supplied to the combustion chamber 2 of the diesel engine according to the operating state of the engine.
0a could not be supplied.

An object of the present invention is to provide a hydraulic pressure generator which prevents damage to a piston or the like and supplies an additional liquid accurately.

[0014]

According to a first aspect of the present invention, there is provided a hydraulic pressure generator including a pressure chamber, a reciprocating piston, a hydraulic chamber and a regulating body. The pressure chamber is supplied with additional liquid.
The piston pressurizes and discharges the additional liquid supplied to the pressure chamber. The hydraulic pressure is supplied to the hydraulic chamber to drive the piston. The regulator is provided in the pressure chamber so as to be movable in the driving direction of the piston, and forms a piston contact surface that faces the end surface of the piston in the driving direction and positions the piston. The drive range of the piston is changed by arbitrarily moving the restriction body. The entire area of the end surface of the piston facing the regulator and the end surface of the hydraulic chamber on which the hydraulic pressure acts is a flat surface. A communication path, which opens in the piston contact surface and through which the additional liquid pressurized and discharged by the piston passes, is formed in the regulation body. The entire area of the piston contact surface except the opening of the communication path is a flat surface.

In the hydraulic pressure generator of the second aspect, a throttle valve is provided in the middle of the supply path for supplying hydraulic pressure to the hydraulic chamber.

[0016]

According to the hydraulic pressure generator of the first aspect, the entire end surface of the piston facing the regulator and the end surface of the hydraulic chamber on which the hydraulic pressure acts are flat, and the opening of the communication passage through which the additional liquid passes is formed. Except for the entire piston contact surface, which is a flat surface,
It is possible to improve the durability against the collision of the opposed end faces of the piston and the restriction body. Moreover, when the hydraulic pressure of the hydraulic chamber is supplied, the piston drives to the pressure chamber side in response to this,
At the same time, the additional liquid can be ejected.

According to the hydraulic pressure generator of the second aspect, since the throttle valve is provided in the middle of the hydraulic pressure supply path for supplying the hydraulic pressure to the hydraulic chamber, the inflow speed of the hydraulic oil into the hydraulic chamber is limited. It is possible to set the driving speed of the piston between the initial driving and the stroke end to a predetermined speed. Therefore, it is possible to mitigate the impact when the piston collides with the regulating body at the stroke end of the piston.

[0018]

Embodiment A hydraulic pressure generator according to an embodiment of the present invention will be described.
A description will be given based on FIGS. 1 to 3. In the description, the same components as those in the conventional example are designated by the same reference numerals and description thereof is omitted.

That is, as shown in FIG. 1, a hydraulic pressure generator 1 includes a pressure chamber 2 to which an additional liquid is supplied and a reciprocating piston which pressurizes and discharges the additional liquid supplied to the pressure chamber 2. 3, a hydraulic chamber 4 to which the hydraulic pressure for driving the piston 3 is supplied, and a restricting body 6 provided in the pressure chamber 2 and having a piston contact surface 5, and the restricting body 6 can be arbitrarily moved in the arrow z direction. By moving, the drive range of the piston 3 is changed. Although not shown in detail in the hydraulic pressure generator 1, the pressure chamber 2 is similar to the conventional example.
A volume changing mechanism 27 is provided for changing the volume of the.

The piston 3 has an end face 3a opposed to the regulating body 6.
The entire area of the end surface 3b on which the hydraulic pressure acts is a flat surface, and the rod 7 projects from the end surface on the hydraulic chamber 4 side. Rod 7
The sensor 8 for detecting the position of the piston 3 is slidably supported by a guide member 9 with its front end face facing the sensor 8. The restricting body 6 forms a communication passage 10 which is opened in the piston contact surface 5 and through which the additional liquid pressurized and discharged by the piston 3 passes, and the communication passage 1 of the piston contact surface 5 is formed.
The entire area except the 0 opening is flat. The hydraulic chamber 4 is
Hydraulic pressure is supplied from the pump device 11 via the solenoid valve 12.

The electromagnetic valve 12 switches between a state in which the supply port 12a and the supply / discharge port 12c communicate with each other and a state in which the discharge port 12b and the supply / discharge port 12c communicate with each other, based on a control signal a from the controller 13. is there. A throttle valve 14 is provided in the supply port 12a. As shown in FIG. 2, the throttle valve 14 is formed by forming a wrench hole 14b and a throttle hole 14c at the center of a main body 14a having a thread formed on the peripheral surface. The hydraulic pressure generator 1 and the solenoid valve 12 are attached to the pipe seat 15, respectively.

The operation of the hydraulic pressure generator 1 and the solenoid valve 12 will be described. First, in a state where the discharge port 12b and the supply / discharge port 12c of the solenoid valve 12 are communicated with each other, the working oil in the hydraulic chamber 4 is supplied to the hydraulic supply / discharge passage 16 of the pipe seat 15, the discharge port 12b of the solenoid valve 12, and the pipe seat 15. It can be freely discharged through the discharge passage 11b. On the other hand, the additional liquid is pressurized by the hydraulic pump 17 and flows into the pressure chamber 2 of the hydraulic pressure generator 1 through the check valve 18 a and the introduction passage 17 a of the pipe seat 15. In this state, since the additional liquid cannot pass through the check valve 18b and flow into the main fuel supply path 19 side, the piston 3 is pushed by the additional liquid in the pressure chamber 2 and moves to the right end. Also, the hydraulic pressure generator 1
The variable volume mechanism 27 attached to the cylinder changes the volume of the pressure chamber 2 in accordance with the operating state of the engine as in the conventional example.

Further, when the solenoid valve 12 is switched to the state in which the supply port 12a and the supply / discharge port 12c are communicated with each other, the pump device 1
1, the hydraulic oil is supplied into the hydraulic chamber 4 of the hydraulic pressure generator 1 through the supply passage 11a of the pipe seat 15 and the hydraulic supply / discharge passage 16.
This hydraulic pressure moves the piston 3 to the left end. As a result, the additional liquid that has flowed into the pressure chamber 2 is not stored in the check valve 18b.
Is pushed open and discharged toward the main fuel supply path 19.

According to the hydraulic pressure generator 1 constructed as described above, when the hydraulic pressure is supplied to the hydraulic chamber 4, the piston 3 is driven to the pressure chamber 2 side in response to this, and at the same time the additional liquid is pressurized. It can be discharged from the chamber 2. For this reason, the discharge timing of the additional liquid becomes accurate as shown in FIG. 3, and it becomes possible to discharge an appropriate amount of the additional liquid according to the operating state of the engine.

Further, the durability of both end surfaces 3a, 3b of the piston 3 and the piston contact surface 5 of the regulating body 6 can be improved. Moreover, since the throttle valve 14 is provided in the middle of the supply port 12a of the solenoid valve 12, the flow rate of the hydraulic oil flowing into the hydraulic chamber 4 through the supply port 12a is limited, so that the piston 3 is initially driven or stroked. The driving speed between the ends can be set to a predetermined speed. Therefore, it is possible to prevent damage due to collision of the piston 3, the restricting body 6, and the guide member 9. Further, even when the additional fuel is supplied to a relatively small engine, it is sufficient to replace the throttle valve 14 with one having a smaller hole, and it is not necessary to replace the pump device 11 with one having a small output. good.

[0026]

According to the hydraulic pressure generator of the first aspect of the invention, the entire area of the end surface of the piston facing the restriction body and the end surface on which the hydraulic pressure on the hydraulic chamber side acts is flat, and the additional liquid of the restriction body passes therethrough. Since the entire area of the piston contact surface other than the opening portion of the passage is a flat surface, the durability against the collision between the opposed end surfaces of the piston and the restricting body can be improved. Therefore, it is possible to prevent damage due to the collision of the piston and the restriction body. In addition, when the hydraulic pressure in the hydraulic chamber is supplied, the piston responds to this and drives the piston to the pressure chamber side, and at the same time, the additional liquid can be discharged. Accordingly, it becomes possible to supply an appropriate amount of additional liquid.

According to the hydraulic pressure generator of the second aspect, since the throttle valve is provided in the middle of the hydraulic pressure supply path for supplying the hydraulic pressure to the hydraulic chamber, the inflow speed of the hydraulic oil into the hydraulic chamber is limited. It is possible to set the driving speed of the piston between the initial driving and the stroke end to a predetermined speed. Therefore, it is possible to suppress the impact when the piston collides with the restriction body at the stroke end of the piston. Further, even when supplying additional fuel to a relatively small engine or the like, the throttle valve may be replaced with one having a small hole, and a hydraulic pump or the like for supplying hydraulic pressure to the hydraulic chamber may be replaced with one having a small output. Productivity is good because there is no need.

[Brief description of drawings]

FIG. 1 is a schematic view showing a state in which a hydraulic pressure generator according to an embodiment of the present invention is attached to an engine.

FIG. 2 is a sectional view of a hydraulic pressure supply path and a throttle valve for supplying hydraulic pressure to a hydraulic pressure generator according to an embodiment of the present invention.

FIG. 3 is a drive characteristic diagram of the piston of the hydraulic pressure generator according to the embodiment of the present invention.

FIG. 4 is a drive characteristic diagram of a piston of a conventional hydraulic pressure generator.

FIG. 5 is a schematic view showing a state in which a conventional hydraulic pressure generator is attached to an engine.

FIG. 6 is an operation explanatory view showing a state in which an additional liquid is supplied to the hydraulic pressure generator of the conventional example.

FIG. 7 is an operation explanatory view showing a state in which an additional liquid is discharged from hydraulic pressure to a hydraulic pressure generator of a conventional example.

[Explanation of symbols]

 1 Liquid pressure generator 2 Pressure chamber 3 Piston 4 Hydraulic chamber 5 Piston contact surface 6 Regulator 14 Throttle valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02M 37/00 341 H

Claims (2)

[Claims] 1. A pressure chamber to which an additional liquid is supplied, a reciprocating piston that pressurizes and discharges the additional liquid supplied to the pressure chamber, and a hydraulic chamber to which a hydraulic pressure for driving the piston is supplied. A movable body that is movable in the driving direction of the piston in the pressure chamber and that has a piston contact surface that faces the end surface of the piston in the driving direction and that positions the piston. In the hydraulic pressure generator configured to change the driving range of the piston, the entire end surface of the piston facing the restriction body and the end surface on which the hydraulic pressure on the hydraulic chamber side acts as a flat surface, and the restriction is performed. The body is provided with a communication passage that opens in the piston contact surface and through which the additional liquid that is pressurized and discharged by the piston passes, and the entire piston contact surface except the opening of the communication passage is formed. Hydraulic generator, characterized in that the surface. 2. The hydraulic pressure generator according to claim 1, wherein a throttle valve is provided in the middle of a hydraulic pressure supply path for supplying hydraulic pressure to the hydraulic chamber.