JP4270111B2 - Regulating valve - Google Patents

Description

  The present invention relates to a regulating valve for regulating fuel pressure.

2. Description of the Related Art Conventionally, an accumulator fuel injection system that injects high-pressure fuel accumulated in a common rail into a cylinder of an internal combustion engine from an injector is known (see Patent Document 1). This accumulator fuel injection system uses a regulating valve that regulates the feed pressure of the feed pump that pumps the fuel from the fuel tank (the pressure of the fuel sent from the feed pump to the high-pressure pump).
As shown in FIG. 6, the regulating valve includes a cylindrical valve body 110 having an inlet 100 on one end side, a piston 120 that is reciprocally inserted into the valve body 110, and the piston 120. It is comprised from the spring 130 etc. which are arrange | positioned behind.

The valve body 110 is provided with a relief hole 140 and an oil drain hole 150 that are opened in the side wall, and an oil reservoir chamber 160 filled with fuel is formed behind the piston 120, and the fuel in the oil reservoir chamber 160 serves as a piston. The oil enters and exits through the oil drain hole 150 according to the behavior of 120.
This regulating valve acts on the piston 120 by balancing the piston 120 at a position where the pressure of the fuel flowing in from the inlet 100 and the fuel pressure of the oil reservoir 160 + the reaction force of the spring 130 are balanced. The fuel pressure (feed pressure of the feed pump) is adjusted to a predetermined value.
Japanese Patent Application No. 2004-127997

  However, in the above-described regulating valve, if air is mixed into the fuel sucked by the feed pump, the fuel pressure acting on the piston 120 becomes unstable, so the piston 120 vibrates and periodically opens and closes (relief holes). By repeating the operation of opening / closing 140), a valve opening / closing sound (an abnormal sound called gulguru) is generated. This valve opening / closing sound becomes annoying when the environmental sound such as idling is small, and may cause discomfort to the driver.

  The present invention has been made based on the above circumstances, and its purpose is to suppress piston vibration by generating a damper action on the piston when the fuel pressure acting on the piston fluctuates rapidly. It is an object of the present invention to provide a regulated valve that can prevent the occurrence of valve opening / closing noise (abnormal noise).

(Invention of Claim 1)
In the regulating valve of the present invention, the pressure of the fuel flowing in from the inlet acts on the front surface of the piston to urge the piston in the valve opening direction, and the reaction force of the spring and the fuel pressure in the oil reservoir chamber are The piston is urged in the valve closing direction and the piston is balanced at a position where both urging forces are balanced, so that the fuel flowing in from the inlet is regulated to a predetermined pressure. When the fuel pressure acting on the fuel fluctuates suddenly, a damper action is generated that suppresses the vibration of the piston by generating a damper action due to the fuel pressure in the oil reservoir, and the relief hole is provided when the piston moves in the valve opening direction. The opening position or the position where the relief hole is fully closed when the piston moves in the valve closing direction is called the open / close position. When the piston is at or near the open / close position, the opening area of the oil drain hole is small. , When the piston is moved to the valve closing side and the valve-opening side from the open and closed positions, as the opening area of the oil drain hole is increased, characterized by varying the opening area of the oil drain hole according to the position of the piston .

According to the above configuration, when the pressure of the fuel flowing in from the inflow port of the body, that is, the fuel pressure acting on the front surface of the piston fluctuates rapidly, the damper action acts on the piston, thereby suppressing the vibration of the piston. The As a result, it is possible to suppress the occurrence of valve opening / closing noise associated with piston vibration.
In addition, since the valve open / close noise is generated when the piston repeatedly opens and closes the relief hole, when the piston is located at or near the open / close position, the opening area of the oil drain hole is reduced, thereby reducing the fuel pressure in the oil reservoir chamber. The vibration of the piston can be suppressed by the damper action using the. Furthermore, when the piston moves from the open / close position to the valve closing side and the valve opening side, the opening area of the oil drain hole is increased, so that the piston can move smoothly, so the pressure regulating function of the regulating valve is maintained well. it can.

(Invention of Claim 2 )
2. The regulating valve according to claim 1 , wherein the piston has a circumferential groove formed on an outer periphery thereof, and a flange-shaped valve portion is provided on a rear end side of the circumferential groove, and the circumferential groove and the oil reservoir are provided on the valve portion. When the piston is in the open / closed position and its vicinity, the valve part closes the rest with the part of the oil drain hole open, and the piston closes the valve from the open / closed position. When moved to the valve opening side, the position of the valve portion is shifted with respect to the oil drain hole, so that the opening area of the oil drain hole is increased.

  According to the above configuration, since the opening area of the oil drain hole is variable depending on the position of the valve portion with respect to the oil drain hole, it is not necessary to reduce the opening area of the oil drain hole opening in the side surface of the body, and the fuel pressure varies. Accordingly, the opening area of the oil drain hole can be increased so that the piston can move smoothly. As a result, when the piston is at the open / close position or in the vicinity thereof, the valve portion largely closes the oil drain hole, so that the opening area of the oil drain hole can be reduced, and as a result, vibration of the piston can be suppressed. Further, when the piston moves from the open / close position to the valve closing side, the position of the valve portion with respect to the oil draining hole is shifted to the valve closing side, so that the opening area of the oil draining hole is increased.

On the other hand, when the piston is moved to the valve opening side of the open and closed positions, if conventional oil drain holes will be closed by the outer circumferential surface of the piston, but the present invention according to claim 2, the valve part to oil drain hole The position is shifted to the valve opening side, and the oil drain hole can be opened by overlapping the positions of the circumferential groove and the oil drain hole. Further, since the circumferential groove and the oil reservoir chamber communicate with each other through the communication hole provided in the valve portion, the fuel is not confined in the oil reservoir chamber and can enter and exit through the oil drain hole.
Thereby, when the piston moves from the open / close position to the valve closing side and the valve opening side, the opening area of the oil drain hole is increased, so that the piston can move smoothly.

(Invention of Claim 3 )
The regulating valve according to claim 2 , wherein the passage cross-sectional area of the communication hole is substantially equal to or larger than the opening area of the oil drain hole.
If the passage cross-sectional area of the communication hole is smaller than the opening area of the oil drain hole, a throttle by the communication hole is provided between the oil reservoir and the oil drain hole when the piston moves from the open / close position to the valve opening side. Therefore, the piston cannot move smoothly. On the other hand, if the passage cross-sectional area of the communication hole is substantially equal to or larger than the opening area of the oil drain hole, the communication hole does not function as a throttle, and the piston can move smoothly.

(Invention of Claim 4 )
The regulating valve according to any one of claims 1 to 3 , wherein the fuel pumped up from the fuel tank by the feed pump is pressurized by the high-pressure pump and pumped to the common rail, and the high-pressure fuel accumulated in the common rail is fed from the injector to the internal combustion engine. It is used for the pressure accumulation type fuel injection system which injects into the cylinder of this, and is characterized by adjusting the pressure of the fuel supplied from the feed pump.

  The best mode for carrying out the present invention will be described in detail with reference to the following examples.

FIG. 1 is a sectional view of a regulating valve, and FIG. 2 is an overall sectional view of a fuel supply pump.
The regulating valve 1 of the present embodiment regulates the feed pressure of the feed pump 2 (pressure of fuel delivered from the feed pump 2) used in, for example, a pressure accumulation fuel injection system for a diesel engine. As shown, the feed pump 2 and the fuel supply pump 3 (the high-pressure pump of the present invention) are assembled together.
The feed pump 2 pumps fuel from a fuel tank (not shown), pressurizes the fuel filtered by the filter 4 to a predetermined pressure, and sends the fuel to the fuel supply pump 3. For example, the feed pump 2 is constituted by a known trochoid pump The diesel engine is driven through the cam shaft 5 of the fuel supply pump 3.

The fuel supply pump 3 includes a cylinder 7 formed in the housing 6 and a plunger 8 inserted into the cylinder 7, and the plunger 8 reciprocates in the cylinder 7 in accordance with the rotation of the cam shaft 5. To do.
The fuel delivered from the feed pump 2 is metered by an electromagnetic metering valve 10 provided in the middle of the suction passage 9 when the plunger 8 moves inside the cylinder 7 toward the camshaft 5 side. The suction valve 11 provided at the end on the opposite side of the camshaft 7 is pushed open to be sucked into the cylinder 7. The fuel sucked into the cylinder 7 is pressurized when the plunger 8 moves in the cylinder 7 toward the side opposite to the camshaft, pushes and opens the discharge valve 13 provided in the discharge passage 12, and a common rail (not shown). It is pumped towards.

Next, the configuration of the regulating valve 1 will be described in detail.
As shown in FIG. 1, the regulator valve 1 includes a cylindrical valve body 14, a piston 15 that is reciprocally inserted into the valve body 14, and a spring that biases the piston 15 in one direction. 16 etc.
One end side (the lower side in the drawing) of the valve body 14 is formed as a fuel inlet 17, and the other end side is closed by a plug 18. A fuel passage 19 (see FIG. 2) leading to the discharge side of the feed pump 2 is connected to the inflow port 17, and a part of the fuel sent from the feed pump 2 flows through the fuel passage 19.

A plurality of relief holes 20 and one oil drain hole 21 are formed in the side wall of the valve body 14. A relief passage 22 (see FIG. 2) that leads to the suction side of the feed pump 2 is connected to the relief hole 20, and when the piston 15 opens the relief hole 20, the fuel that flows in from the inlet 17 flows out of the relief hole 20. Then, the gas flows back to the suction side of the feed pump 2 through the relief passage 22.
The oil drain hole 21 opens to the other end side from the relief hole 20 and is provided in communication with an oil reservoir chamber 23 formed behind the piston 15 (reverse flow inlet side) inside the valve body 14. The relief passage 22 is connected to the relief passage 22 through a drawing passage 24 (see FIG. 3). However, the oil drain hole 21 of the present embodiment is provided with a smaller opening area than the oil drain hole 150 formed in the conventional regulated valve.

The piston 15 moves inside the valve body 14 and varies the opening area of the relief hole 20 by the pressure of the fuel flowing in from the inlet 17, that is, the fluctuation of the fuel pressure acting on the front surface of the piston 15.
The spring 16 is accommodated behind the piston 15 (oil reservoir chamber 23), and biases the piston 15 against the fuel pressure acting on the front surface of the piston 15. Accordingly, the piston 15 is balanced at a position where the fuel pressure acting on the front surface of the piston 15 and the fuel pressure acting on the back surface (rear surface) + the reaction force of the spring 16 are balanced.

Next, the oil drain hole 21 will be described in detail.
The oil drain hole 21 is set to have a small opening area up to a level at which the piston 15 does not vibrate when the fuel pressure acting on the front surface of the piston 15 fluctuates rapidly.
The cross-sectional area of the oil drain hole 21 is set based on the following logic.
When the piston 15 is stable at a predetermined position, that is, when the feed pressure of the feed pump 2 is adjusted to a predetermined pressure by the regulator valve 1, the fuel pressure P1 and the oil acting on the front surface of the piston 15 The following formula (1) is established between the fuel pressure P2 in the reservoir chamber 23 and the reaction force Fs of the spring 16 (see FIG. 3).
P1 ・ Sa = Fs + P2 ・ Sa ……………………………… (1)
(Sa: sectional area of piston 15)

On the other hand, when the fuel pressure acting on the front surface of the piston 15 fluctuates (for example, increases) to P1 ′, the piston 15 moves in the counterflow inlet direction (arrow direction shown in the figure) as shown in FIG. Since the fuel pressure in the oil reservoir 23 increases to P2 ′, the fuel in the oil reservoir 23 flows out from the oil drain hole 21. At this time, the following equation (2) is established between the moving speed V of the piston 15 and the flow velocity U of the fuel flowing out from the oil drain hole 21.
V ・ Sa ＝ U ・ Sb ………………………………………… (2)
(Sb: sectional area of oil drain hole 21)
Here, when the fuel pressure acting on the front surface of the piston 15 fluctuates, if the piston 15 vibrates when the moving speed V of the piston 15 exceeds a predetermined speed Vmax, V ≦ Vmax If it is good. When this is applied to the above (2), the following formula (3) is established.
U · Sb ≦ Vmax · Sa ……………………………… (3)

The flow velocity U of the fuel flowing out from the oil drain hole 21 is obtained as a function of the pressure change amount ΔP = P2′−P2 of the oil reservoir chamber 23 accompanying the movement of the piston 15 and the cross-sectional area Sb of the oil drain hole 21. The above (3) is replaced by the following mathematical formula (4).
U (ΔP, Sb) · Sb ≦ Vmax · Sa (4)
As a result, a cross-sectional area Sb that satisfies the mathematical expression (4) is set according to ΔP (depending on the use conditions), Vmax, and Sa.

Next, the operation and effect of the regulating valve 1 will be described.
The regulator valve 1 is fed from the feed pump 2 by balancing the piston 15 at a position where the pressure of the fuel flowing in from the inlet 17 and the fuel pressure of the oil reservoir 23 + the reaction force of the spring 16 are balanced. The fuel to be discharged is regulated to a predetermined pressure.
Here, when air is mixed into the fuel sucked by the feed pump 2, the fuel pressure acting on the front surface of the piston 15 becomes unstable. Therefore, in the conventional regulating valve having a large opening area of the oil drain hole 21, As the valve 15 vibrates and the relief hole 20 is repeatedly opened and closed, a valve opening / closing sound is generated.

  On the other hand, in the regulating valve 1 of this embodiment, since the opening area of the oil drain hole 21 is smaller than the conventional one, the oil drain hole 21 functions as a throttle. As a result, when the piston 15 moves, the amount of fuel that can enter and exit the oil reservoir chamber 23 through the oil drain hole 21 is suppressed, so that a damper action due to the fuel pressure in the oil reservoir chamber 23 acts on the behavior of the piston 15. . As a result, even if the fuel pressure acting on the front surface of the piston 15 fluctuates abruptly, the vibration of the piston 15 is suppressed by the damper action, so that the piston 15 does not repeat opening and closing of the relief hole 20 and the valve opening / closing sound. Can be prevented.

FIGS. 5A to 5C are operation explanatory views of the regulating valve 1.
The regulating valve 1 according to the second embodiment is configured to vary the opening area of the oil drain hole 21 in accordance with the position of the piston 15.
As shown in FIG. 5, a circumferential groove 25 is formed on the outer periphery of the piston 15, and a flange-like valve portion 26 is provided on the rear end side of the circumferential groove 25, and the circumferential groove 25 is provided in the valve portion 26. A communication hole 27 that communicates with the oil reservoir chamber 23 is formed. The circumferential groove 25 has substantially the same groove width as the opening area of the oil drain hole 21 and is formed at a predetermined depth from the outer circumferential surface of the piston 15 radially inward over the entire circumference of the piston 15. For example, the communication hole 27 is provided at a plurality of locations in the circumferential direction of the valve portion 26, and the total cross-sectional area of all the communication holes 27 is approximately equal to or larger than the opening area of the oil drain hole 21. Is provided.

When the piston 15 is located closer to the valve closing side than the position at which the relief hole 20 is opened / closed (referred to as the opening / closing position), the position of the valve portion 26 with respect to the oil drain hole 21 is as shown in FIG. By shifting to the valve closing side, the opening area of the oil drain hole 21 is increased.
The “open / close position” refers to a position at which the relief hole 20 starts to open when the piston 15 moves in the valve opening direction (direction to open the relief hole 20) or the relief hole 20 when the piston 15 moves in the valve closing direction. Says the fully closed position.

When the piston 15 is located in the vicinity of the open / close position, as shown in FIG. 5 (b), the valve portion 26 closes the rest of the oil drain hole 21 in a state where a part of the oil drain hole 21 is opened. The opening area is reduced.
When the piston 15 is positioned on the valve opening side from the open / close position, the position of the valve portion 26 is shifted to the valve opening side with respect to the oil drain hole 21 as shown in FIG. The oil drain hole 21 can be opened by overlapping the positions of the oil drain hole 21 and the oil drain hole 21. Further, since the circumferential groove 25 and the oil reservoir chamber 23 communicate with each other through the communication hole 27 provided in the valve portion 26, the fuel is not confined in the oil reservoir chamber 23 and can enter and exit through the oil drain hole 21.

  According to said structure, since the opening area of the oil drain hole 21 is changed with the position of the valve part 26 with respect to the oil drain hole 21, it is necessary to make the opening area of the oil drain hole 21 opened to the side surface of the valve body 14 small. In addition, the opening area of the oil drain hole 21 can be increased so that the piston 15 can move smoothly according to the pressure fluctuation of the fuel flowing in from the inlet 17. Thereby, when the piston 15 is located in the vicinity of the open / close position, the valve portion 26 largely closes the oil drain hole 21 so that the opening area of the oil drain hole 21 can be reduced. As a result, as described in the first embodiment, a damper action caused by the fuel pressure in the oil reservoir chamber 23 acts on the piston 15 to suppress the vibration of the piston 15 and prevent the valve opening / closing sound from being generated. Further, when the piston 15 moves from the opening / closing position to the valve closing side and the valve opening side, the position of the valve portion 26 with respect to the oil draining hole 21 is shifted, so that the opening area of the oil draining hole 21 is increased and the piston 15 is smoothly moved. I can move.

  The regulator valve 1 described in the second embodiment is configured so that a damper effect is obtained with respect to the piston 15 when the piston 15 is in the vicinity of the open / close position. However, the oil drain hole 21 and the circumferential groove 25 are provided. The damper effect can be obtained at any piston position by appropriately changing the positional relationship between

(Example 1) which is sectional drawing of a regulating valve. It is a whole sectional view of a fuel supply pump. It is sectional drawing of the regulating valve explaining the balance state of the force which acts on a piston. It is sectional drawing of the regulating valve explaining the action | operation at the time of a pressure fluctuation. (Example 2) which is operation | movement explanatory drawing of a regulating valve. It is sectional drawing of a regulating valve (prior art).

Explanation of symbols

1 Regulating valve 2 Feed pump 3 Fuel supply pump (high pressure pump)
14 Valve body (body)
15 Piston 16 Spring 17 Inlet 20 Relief hole 21 Oil drain hole (vibration suppression means)
23 Oil reservoir 25 Circumferential groove 26 Valve part 27 Communication hole

Claims (4)

A body in which an inflow port for injecting fuel is formed on one end side of the cylindrical shape;
A relief hole opening in the side of this body,
A piston that is reciprocally inserted into the body and changes an opening area of the relief hole in accordance with a pressure fluctuation of fuel flowing in from the inlet;
A spring that biases the piston against the pressure of fuel flowing in from the inlet;
An oil reservoir chamber formed behind the piston inside the body and filled with fuel;
An oil drain hole that communicates with the oil reservoir chamber and opens in a side surface of the body, through which fuel in the oil reservoir chamber enters and exits according to the behavior of the piston;
The pressure of the fuel flowing in from the inflow port acts on the front surface of the piston to urge the piston in the valve opening direction, and the reaction force of the spring and the fuel pressure of the oil reservoir chamber act on the back surface of the piston. Then, the piston is urged in the valve closing direction, and the piston is balanced at a position where both urging forces are balanced, thereby regulating the fuel flowing in from the inlet to a predetermined pressure. And
When a fuel pressure acting on the front surface of the piston suddenly fluctuates, a damper action is generated by suppressing a vibration of the piston by generating a damper action due to the fuel pressure in the oil reservoir chamber ,
The position at which the relief hole starts to open when the piston moves in the valve opening direction or the position at which the relief hole is fully closed when the piston moves in the valve closing direction is called an open / close position.
The opening area of the oil drain hole is small when the piston is at and near the open / close position, and the opening area of the oil drain hole is large when the piston moves from the open / close position to the valve closing side and the valve opening side. Thus , the regulating valve is characterized in that the opening area of the oil drain hole is varied in accordance with the position of the piston . The regulated valve according to claim 1,
The piston has a circumferential groove formed on the outer periphery, a flange-shaped valve portion is provided on the rear end side of the circumferential groove, and a communication hole that connects the circumferential groove and the oil reservoir chamber to the valve portion. Formed,
When the piston is at or near the open / close position, the valve portion closes the rest with a part of the oil drain hole opened, and the piston moves from the open / close position to the valve closing side and the valve opening side. When this is done, the position of the valve portion is shifted with respect to the oil drain hole, so that the opening area of the oil drain hole is increased . The regulated valve according to claim 2,
The regulating valve according to claim 1, wherein a passage sectional area of the communication hole is substantially equal to or larger than an opening area of the oil drain hole . Either regulation valve according to claim 1 to 3. These,
The fuel pumped up from the fuel tank by the feed pump is pressurized by the high pressure pump and pumped to the common rail, and is used in a pressure accumulation fuel injection system that injects the high pressure fuel accumulated in the common rail into the cylinder of the internal combustion engine from the injector,
Regulation valve, characterized in that the pressure-regulating the pressure of fuel supplied from the feed pump.

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