JP2023135091A - fuel pressure adjustment valve - Google Patents

Abstract

To provide a fuel pressure adjustment valve manufactured comparatively inexpensively, and capable of suppressing leakage of fuel from an injector when a fuel pump is not operated, and to contribute to improvement of efficiency of energy.SOLUTION: A fuel pressure adjustment valve 1 is a member for adjusting a fuel pressure from a fuel pump. The fuel pressure adjustment valve 1 includes a housing 11, a diaphragm 14, a valve seat member 15 having a valve seat 15a, a valve element 16 supported by the diaphragm 14 and provided to open and close the valve seat 15a, and a first spring member and a second spring member for energizing the valve element 16 in a valve close direction. The first spring member 17 is always in contact with the valve element 16, and the second spring member 18 has one end which is held apart from the valve element 16 until the valve element 16 reaches a prescribed lift amount from a valve close position.SELECTED DRAWING: Figure 2

Description

The present invention relates to a fuel pressure regulating valve that is disposed in a fuel supply system of an internal combustion engine and regulates the pressure of fuel from a fuel pump.

In recent years, research and development has been conducted to improve fuel efficiency and contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy.

In an internal combustion engine, in order to accurately control the fuel injected from an injector, it is necessary to keep the fuel pressure (fuel pressure) in a fuel supply path communicating with the injector constant. For this reason, a fuel pressure adjustment valve is provided that opens and closes a return flow path that branches from the fuel supply path and returns excess fuel to the fuel tank.

Some types of fuel pressure regulating valves include a valve seat and a valve body supported by a diaphragm and biased in the valve closing direction by a compression coil spring. When the fuel pump is not operating, the fuel pressure adjustment valve is closed by the biasing force of the compression coil spring. When the fuel pressure reaches a predetermined value during operation of the fuel pump, the fuel pressure pushes out the diaphragm against the biasing force of the compression coil spring, thereby opening the fuel pressure regulating valve. Therefore, a portion of the fuel returns to the fuel tank through the return passage, and the fuel pressure in the fuel supply passage at this time becomes the upper limit of the fuel pressure, and the fuel pressure is maintained at this upper limit value. For example, Patent Document 1 discloses a fuel pressure regulating valve that includes a main spring that biases a valve body, a sub-spring made of a shape memory alloy that biases the valve body, and a heater that increases the ambient temperature of the sub-spring. Are listed. The fuel pressure regulating valve described in Patent Document 1 can increase the biasing force in the valve closing direction by extending the sub spring using a heater and changing the spring constant. This prevents vapor lock, that is, a phenomenon in which the fuel in the fuel pipe or fuel pump vaporizes and interferes with fuel supply.

It has also been proposed to use two valves to regulate fuel pressure. For example, in Patent Document 2, a return flow path is provided with an electromagnetic on-off valve and a pressure regulating mechanism (valve) that adjusts the fuel pressure to a lower fuel pressure than the fuel pressure during operation, and is opened and closed when the internal combustion engine is stopped. It is described that the valve is opened for a predetermined period of time to reduce the fuel pressure in the fuel supply passage by a pressure regulating mechanism. Furthermore, Patent Document 3 discloses a pressure regulating valve that adjusts the fuel pressure to a first pressure when the fuel pump is in operation, and a residual pressure holding valve that maintains the fuel pressure at a second pressure lower than the first pressure when the fuel pump is not operating. It is stated that the following shall be provided.

Japanese Patent Publication No. 167155/1983 Japanese Patent Application Publication No. 2005-090232 Japanese Patent Application Publication No. 2007-239682

By the way, when the fuel pump is not operating, the fuel remaining in the fuel supply path expands or contracts due to fluctuations in outside temperature, causing fluctuations in fuel pressure. When the fuel pressure increases, fuel leaks from the injector's core valve into the combustion chamber, vaporizes, and stays in the combustion chamber. Therefore, when the engine is started, fuel becomes excessive, and the startability of the internal combustion engine deteriorates. Techniques for improving fuel efficiency need to address such problems.

By applying the valves described in Patent Documents 1 to 3, it is possible to suppress leakage of fuel from the injector when the fuel pump is not operating. However, the valve described in Patent Document 1 requires a heater, which increases manufacturing costs. Furthermore, the structure described in Patent Document 2 or 3 requires two valves, which increases manufacturing costs.

SUMMARY OF THE INVENTION In order to solve the above problems, it is an object of the present invention to provide a fuel pressure regulating valve that can be manufactured at a relatively low cost and that can suppress leakage of fuel from an injector when a fuel pump is not in operation. This contributes to energy efficiency.

In order to solve the above problems, an aspect of the present invention is a fuel pressure adjustment valve (1, 31) that adjusts the pressure of fuel supplied from a fuel pump (6), which includes a fuel inlet (22) and a fuel outlet ( a housing (11) defining an inner chamber; and a fuel chamber (13) supported by the housing and partitioning the inner chamber into a spring chamber (12) and a fuel chamber (13) communicating with the fuel inlet and the fuel outlet. a diaphragm (14), the fuel chamber is divided into an inlet chamber (27) formed on the diaphragm side and communicating with the fuel inlet, and an outlet chamber (28) communicating with the fuel outlet; a valve seat member (15) forming a facing valve seat (15a); a valve body (16) supported by the diaphragm (14) so as to be able to open and close the valve seat; a first spring member (17) that always biases the valve in the valve closing direction; The second spring member (18) has one end that is held and biases the valve element in the valve closing direction when the valve element is lifted beyond the lift position.

According to this aspect, the first spring member defines the upper limit of the fuel pressure when the fuel pump is stopped, and the first and second spring members define the upper limit of the fuel pressure when the fuel pump is in operation. This prevents fuel from leaking from the injector when the fuel pump is stopped, improving the startability of the internal combustion engine, and keeping the fuel pressure constant when the fuel pump is operating, which in turn contributes to energy efficiency. . Further, since two-step pressure regulation can be performed with one fuel pressure regulating valve having a relatively small number of parts, the fuel pressure regulating valve can be manufactured at low cost.

In the above aspect, the first spring member (17) and the second spring member (18) each include a compression coil spring extending along a common central axis, and the first spring member The first spring member and the second spring member are arranged inside the spring member, and the center axis of the first spring member and the second spring member are arranged to pass through the center of the valve body (16). a contact member (19) that is attached to the one end and includes an annular contact surface (26) that can cover the one end of the second spring member from the valve body side and come into contact with the valve body; ) may further be included.

According to this aspect, by arranging the first spring member inward of the second spring member, the first spring member and the second spring member can be arranged compactly, and the enlargement of the fuel pressure adjustment valve is suppressed. be done. Further, since the first and second spring members bias the central portion of the valve body, and the second spring member biases the valve body via the abutting member, the first and second spring members are balanced. It is possible to provide a good biasing force to the valve body, and the biasing force can be easily separated.

In the above aspect, the one end portion of the second spring member (18) may not be restricted from being displaced in the valve closing direction in a state separated from the valve body (16).

According to this aspect, since the number of parts is relatively small, the fuel pressure regulating valve can be manufactured at low cost.

In the above aspect, the second spring member (18) is supported by the housing (11) so as to be disposed in the spring chamber (12), and the second spring member (18) is spaced apart from the valve body (16). The valve may further include a disc spring member (32) that restricts displacement of the one end of the spring member in the valve closing direction.

According to this aspect, it becomes easy to set the fuel pressure during operation of the fuel pump.

According to the above aspect, it is possible to provide a fuel pressure regulating valve that can be manufactured at a relatively low cost and can suppress leakage of fuel from an injector when the fuel pump is not in operation, which in turn contributes to energy efficiency. I can contribute.

A sectional view showing a fuel device including a fuel pressure adjustment valve according to a first embodiment A sectional view showing the fuel pressure adjustment valve according to the first embodiment (when the fuel pump is not operating) A sectional view showing the fuel pressure adjustment valve according to the first embodiment (when the fuel pump is in operation) A diagram showing the relationship between the fuel pressure and the operating/non-operating state of the fuel pump in a fuel system equipped with a fuel pressure adjustment valve according to the first embodiment. A diagram showing temporal changes in fuel pressure in a fuel system equipped with a fuel pressure adjustment valve according to the first embodiment. A sectional view showing the fuel pressure adjustment valve according to the second embodiment (when the fuel pump is not operating)

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a fuel pump module 2 including a fuel pressure regulating valve 1 according to a first embodiment.

The fuel pump module 2 includes a reservoir 4 arranged in a fuel tank 3 of a vehicle, and a fuel pump 6 that sucks fuel in the reservoir 4 through a suction filter 5 and discharges it toward an internal combustion engine (not shown). a strainer 7 that filters the fuel discharged from the fuel pump 6; a fuel supply pipe 9 that connects the strainer 7 and the injector 8 to define a fuel supply path therein; A return pipe 10 defining therein a return flow path returning to the tank 3; and a return pipe 10 provided to connect the return pipe 10 to the fuel supply pipe 9 or to be disposed at an intermediate portion of the return pipe 10; and a fuel pressure adjustment valve 1 that opens and closes.

FIG. 2 shows the fuel pressure regulating valve 1 when the fuel pump 6 (see FIG. 1) is not operating, that is, when the internal combustion engine is stopped, and FIG. 3 shows the fuel pressure regulating valve 1 when the fuel pump 6 is operating, that is, when the internal combustion engine is stopped. The fuel pressure regulating valve 1 is shown when the internal combustion engine is operating. As shown in FIGS. 2 and 3, the fuel pressure adjustment valve 1 includes a housing 11, a diaphragm 14 supported by the housing 11, and partitioning the inner chamber of the housing 11 into a lower spring chamber 12 and an upper fuel chamber 13. , a valve seat member 15 forming a valve seat 15a in the fuel chamber 13, a valve body 16 supported by the diaphragm 14 and provided so as to be able to open and close the valve seat 15a in the fuel chamber 13, and a spring chamber 12. a first spring member 17 provided within the spring chamber 12; a second spring member 18 provided within the spring chamber 12; and a contact member attached to one end of the second spring member 18 facing the valve body 16. 19.

The housing 11 is a cylindrical member that is generally rotationally symmetrical with respect to a central axis that extends in the vertical direction, and is made of steel or resin. The interior of the housing 11 is divided into a lower spring chamber 12 and an upper fuel chamber 13 by a diaphragm 14 . The housing 11 includes a large diameter section 20 that supports the diaphragm 14, a small diameter section 21 that is provided above the large diameter section 20 and has a smaller diameter than the large diameter section 20, and the large diameter section 20 and the small diameter section 21. A plurality of fuel inlets 22 are provided to extend vertically through an annular portion extending horizontally, and a plurality of fuel inlets 22 are provided to pass through the upper end of the housing 11 along the central axis. A fuel outlet 23 is provided. The fuel inlet 22 communicates with the inside (fuel supply path) of the fuel supply pipe 9 (see FIG. 1), and the fuel outlet 23 communicates with the inside of the fuel tank 3 (see FIG. 1) via the inside of the return pipe 10. .

The diaphragm 14 is flexible and has a disk shape. The diaphragm 14 is supported by the housing 11 at its peripheral edge and is disposed perpendicular to the central axis of the housing 11.

The valve seat member 15 is a bottomless cylindrical member, and is disposed within the fuel chamber 13 of the housing 11 so that its upper portion fits inside the small diameter portion 21 . The lower end of the valve seat member 15 includes a ring-shaped valve seat 15a and an opening formed inside the valve seat 15a in the radial direction.

The valve body 16 has a pair of connecting parts 24 that sandwich the diaphragm 14 from above and below so as to be supported by the diaphragm 14, and is fixed to the upper surface of the upper connecting part 24 in the fuel chamber 13, so that the valve seat 15a can be opened and closed. and a valve body portion 25. The valve body 16 is attached to the center of the diaphragm 14 in the radial direction.

The first spring member 17 and the second spring member 18 are provided within the spring chamber 12 and include compression coil springs. The outer diameter of the first spring member 17 is smaller than the inner diameter of the second spring member 18, and the first spring member 17 is arranged radially inward of the second spring member 18. The first spring member 17 and the second spring member 18 are arranged along the central axis of the housing 11, and their lower ends are fixed to the lower part of the housing 11. The upper end portion of the first spring member 17 is always in contact with the valve body 16 within the spring chamber 12 so that the first spring member 17 always biases the valve body 16 in the valve closing direction. The upper end portion of the second spring member 18 is held apart from the valve body 16 until the valve body 16 reaches a predetermined lift position from the valve close position, and When the valve body 16 is lifted beyond this point, the valve body 16 is energized. The length of the second spring member 18 is set to satisfy such conditions, and the upper end of the second spring member 18 is prevented from being displaced in the valve closing direction when it is separated from the valve body 16. It has not been. The upper end portions of the first spring member 17 and the second spring member 18 abut on an annular portion of the valve body 16 centered on the radial center of the lower connecting portion 24 .

The contact member 19 is attached to the upper end of the second spring member 18 , covers the upper end of the second spring member 18 from the valve body 16 side, and comes into contact with the lower connecting portion 24 of the valve body 16 . A possible annular contact surface 26 is provided. The contact member 19 includes a bottom wall that is annular in plan view and has a contact surface 26, and a cylindrical side wall that extends downward from the outer edge of the bottom wall in the radial direction. The portion of the valve body 16 that contacts the contact surface 26 and the contact surface 26 form a plane perpendicular to the central axis of the housing 11 .

The fuel chamber 13 of the housing 11 is defined by the inner peripheral surface of the large diameter portion 20, the diaphragm 14, the valve body 16, and the outer peripheral surface of the lower part of the valve seat member 15, and includes an inlet chamber 27 communicating with the fuel inlet 22; It is defined by the inner circumferential surface of the valve seat member 15 and the inner circumferential surface of the small diameter portion 21 and is divided into an outlet chamber 28 that communicates with the fuel outlet 23 . When the valve body 16 is biased by the first spring member 17 and pressed against the valve seat 15a, the inlet chamber 27 is sealed against the outlet chamber 28.

When the fuel pressure in the inlet chamber 27 is lower than a preset first pressure, the valve body 16 is pressed against the valve seat 15a by the biasing force of the first spring member 17, as shown in FIG. When the fuel pressure in the inlet chamber 27 exceeds the first pressure, the valve body 16 moves away from the valve seat 15a against the biasing force of the first spring member 17, and the fuel that has flowed into the inlet chamber 27 is transferred to the outlet chamber 28 and the return pipe. 10 and flows out into the fuel tank 3 (see FIG. 1). The first pressure is a value sufficiently lower than the fuel pressure during operation of the fuel pump 6 (see FIG. 1). When the pressure in the inlet chamber 27 reaches a second pressure that is higher than the first pressure, the lift amount of the valve body 16 exceeds a predetermined value, and the valve body 16 is moved through the abutment member 19 as shown in FIG. The second spring member 18 comes into contact with the lower end of the second spring member 18, and receives a biasing force not only from the first spring member 17 but also from the second spring member 18. As fuel flows out from the gap between the valve seat 15a and the valve body 16, the urging force of the first spring member 17 and the second spring member 18 on the valve body 16 and the force of the fuel pressure pushing the diaphragm 14 and the valve body 16 are reduced. Balance keeps fuel pressure constant. The length and spring constant of the first spring member 17 are set to define the first pressure, and the lengths and spring constants of the first spring member 17 and the second spring member 18 are set to define the second pressure. is set to

FIG. 4 shows the fuel pressure inside the fuel supply pipe 9 (see FIG. 1) when the fuel pump 6 (see FIG. 1) is activated and when it is not activated. The first pressure is set to, for example, 160 kPa, and the second pressure is set to, for example, 340 kPa. As shown in FIGS. 1 to 4, since the inlet chamber 27 of the fuel pressure adjustment valve 1 communicates with the inside of the fuel supply pipe 9, the fuel pressure in the inlet chamber 27 and the fuel pressure inside the fuel supply pipe 9 are equal to each other. . When the fuel pump 6 is operated, the fuel pressure increases and stabilizes at the second pressure. This is because the biasing forces of the first spring member 17 and the second spring member 18 against the valve body 16 in the valve closing direction are balanced by the force of the fuel pressure pushing the diaphragm 14 and the valve body 16. When the operation of the fuel pump 6 is stopped, the fuel pressure inside the fuel supply pipe 9 becomes the first pressure or lower. This is because when the fuel pressure exceeds the first pressure, the fuel pressure moves the valve body 16 away from the valve seat 15a against the biasing force of the first spring member 17, and the fuel passes through the outlet chamber 28 and the inside of the return pipe 10. This is because it flows out into the fuel tank 3.

FIG. 5 shows the changes in fuel pressure and the cumulative leakage amount of fuel from the injector 8 (see FIG. 1) when the operation of the fuel pump 6 is stopped for a long period of time. 1 shows a fuel pressure adjustment valve 1 according to the invention. The fuel pressure inside the fuel supply pipe 9 (see FIG. 1) is affected by the outside temperature. In conventional fuel pressure regulating valves, even if the fuel expands and the fuel pressure increases, the valve remains closed until the fuel pressure exceeds its upper limit. For this reason, when the outside temperature rises during the day, the fuel expands, the fuel pressure increases, and the amount of fuel leakage increases. On the other hand, in the fuel pressure regulating valve 1 according to the embodiment, when the fuel pressure exceeds the first pressure (160 kPa), the valve opens against the urging force of the first spring member 17, so that the fuel pressure substantially exceeds the first pressure. The leakage of fuel from the injector 8 is suppressed.

The effects of the fuel pressure regulating valve 1 will be explained. When the fuel pressure exceeds the first pressure, the valve body 16 urged by the first spring member 17 moves away from the valve seat 15a, and a portion of the fuel is moved from inside the fuel supply pipe 9 toward the fuel tank 3. Therefore, leakage of fuel from the injector 8 due to an increase in fuel pressure while the fuel pump 6 is stopped is suppressed, improving the startability of the internal combustion engine and contributing to energy efficiency. While the fuel pump 6 is in operation, the first spring member 17 and the second spring member 18 bias the valve element 16, which is spaced apart from the valve seat 15a, in the valve closing direction, thereby keeping the fuel pressure constant.

Since pressure can be adjusted in two stages with one fuel pressure regulating valve 1 having a relatively small number of parts, the fuel pressure regulating valve 1 can be manufactured at low cost.

By arranging the first spring member 17 inside the second spring member 18, the first spring member 17 and the second spring member 18 can be arranged compactly, and the enlargement of the fuel pressure adjustment valve 1 is suppressed. Ru.

Since the abutting surface 26 of the abutting member 19 and the portion of the valve body 16 that abuts the abutting surface 26 form a plane perpendicular to the central axis of the housing 11, the second spring member 18 supports the valve in a well-balanced manner. A biasing force can be applied to the body 16, and the biasing force can be easily separated.

The first spring member 17 biases the center portion of the valve body 16 in the radial direction, and the second spring member 18 biases the center portion of the valve body 16 in the radial direction via the contact member 19. Therefore, the first spring member 17 and the second spring member 18 can reliably hold the valve body 16 and suppress pulsation that the valve body 16 receives due to high fuel pressure.

Referring to FIG. 6, a fuel pressure regulating valve 31 according to a second embodiment of the present invention will be described. Components that are common to those in the first embodiment are given the same reference numerals and explanations will be omitted. The fuel pressure regulating valve 31 according to the second embodiment differs from the first embodiment in that it includes a disc spring member 32, and the other configurations are the same as those in the first embodiment.

The disc spring member 32 has an annular shape, is supported by the housing 11 around the outer periphery, and is a second spring member separated from the valve body 16 through the abutment member 19 around the inner periphery. 18 is supported. When the fuel pressure increases, the valve body 16 pushes down the upper end of the second spring member 18 together with the disc spring member 32. By providing the disc spring member 32, the second pressure can be easily set.

This concludes the description of the specific embodiments, but the present invention is not limited to the above embodiments and modifications, and can be implemented in a wide range of modifications. The fuel pressure adjustment valve may be installed upside down, sideways, or inclined with respect to the up-down direction. The first and second spring members may be provided with other springs such as disc springs instead of the compression coil springs. The diaphragm may have an annular shape, and the valve body may fit into the inner peripheral edge of the diaphragm.

1: Device 1, 31: Fuel pressure adjustment valve 11: Housing 12: Spring chamber 13: Fuel chamber 14: Diaphragm 15: Valve seat member 15a: Valve seat 16: Valve body 17: First spring member 18: Second spring member 19 : Contact member 22 : Fuel inlet 23 : Fuel outlet 27 : Inlet chamber 28 : Outlet chamber 32 : Belleville spring member

Claims (4)

A fuel pressure adjustment valve that adjusts the pressure of fuel supplied from a fuel pump,
a housing having a fuel inlet and a fuel outlet and defining an interior chamber;
a diaphragm supported by the housing and partitioning the inner chamber into a spring chamber and a fuel chamber communicating with the fuel inlet and the fuel outlet;
a valve seat member that partitions the fuel chamber into an inlet chamber formed on the diaphragm side and communicates with the fuel inlet and an outlet chamber that communicates with the fuel outlet, and forms a valve seat facing the inlet chamber;
a valve body supported by the diaphragm so as to be able to open and close the valve seat;
a first spring member provided in the spring chamber and constantly biasing the valve body in a valve closing direction;
One end portion is provided in the spring chamber and is held in a state separated from the valve body until the valve body reaches a predetermined lift position from the valve closing position, and when the valve body exceeds the lift position. a second spring member that biases the valve body in the valve closing direction when lifted. The first spring member and the second spring member each include a compression coil spring extending along a common central axis,
The first spring member is disposed inside the second spring member, and the first spring member and the second spring member are disposed such that the central axis passes through a central portion of the valve body,
A contact that is attached to the one end of the second spring member and includes an annular contact surface that can come into contact with the valve body while covering the one end of the second spring member from the valve body side. The fuel pressure regulating valve according to claim 1, further comprising a member. 3. The fuel pressure regulating valve according to claim 1, wherein the one end of the second spring member is not restricted from being displaced in the valve closing direction in a state separated from the valve body. a plate supported by the housing so as to be disposed in the spring chamber, and regulating displacement of the one end of the second spring member in the valve closing direction when the second spring member is separated from the valve body; The fuel pressure regulating valve according to claim 1 or 2, further comprising a spring member.

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