JP3808491B2 - Solenoid valve - Google Patents

Description

  The present invention relates to a solenoid valve that controls supply of fuel evaporative gas generated from a fuel tank to an intake pipe.

  FIG. 6 is a longitudinal sectional view showing a conventional solenoid valve, in which 101 is a resin housing provided with an input port 102 and an output port 103 to which negative pressure is applied, and 104 is a resin in which a coil 105 is contained. A cover 106 made of a magnetic material (made of iron) is provided between the housing 101 and the cover 104 and forms a magnetic path with the core 107, and 108 is a U-shaped magnet that forms a magnetic path with the plate 106. This is a body (iron) yoke.

  109 is provided in a connector 110 for supplying power to the coil 105, a connector hole into which an external socket (not shown) is inserted, and 111 communicates with an input port (negative pressure application port) 102 formed in the housing 101. A flow path, 112 is a flow path that communicates with the output port 103 formed in the housing 101, 113 is a pin that is partially protruded from one axial center of the core 107, and 114 is a plunger that is fitted outside the pin 113 , 115 is a valve body provided at one end of the plunger 114, 116 is a spring which is contracted between the core 107 and the plunger 114, and always closes the flow path 111 by bringing the valve body 115 into contact with the end face of the housing 101, Reference numeral 117 denotes a leaf spring provided on the plunger 114, and a seal member 118 is integrally provided on the periphery of the leaf spring. . Reference numeral 119 denotes an attachment seat for attaching the solenoid valve to a fixed portion (not shown), and 120 denotes an attachment bolt for attaching the attachment seat 119 to an external device.

Next, the operation will be described.
First, when the coil 105 is not energized from an external power source (not shown), the valve element 115 of the plunger 114 is pressed against the end surface of the housing 101 by the urging force of the spring 116, and the communication portion of the flow paths 111 and 112 is closed. The communication path between the input port 102 and the output port 103 is closed.

  In this state, when the coil 105 is energized to generate a magnetic field, the magnetic force causes the plunger 114 to move against the spring 116, and the valve body 115 is separated from the end face of the housing 101 to connect the flow paths 111 and 112. Since the negative pressure is applied to the input port 102, the fluid supplied from the output port 103 passes through the flow paths 111 and 112 and is discharged from the input port 102.

  In this case, the coil 105 is energized intermittently, and the valve body 115 intermittently opens and closes the communicating portion of the flow paths 111 and 112. Is transmitted to the device to which the output port 103 is connected, and the same frequency component as the natural vibration frequency of the device resonates in the device, causing a troubled resonance.

  Further, when the pipe length connecting the output port 103 and an external device (not shown) is an even multiple of a quarter wavelength of the natural vibration frequency component, this frequency component is amplified by resonance in the pipe. Since it is emitted to the device, the resonance sound of the external device is further increased.

  Further, pulsation is generated in the fluid discharged from the flow path 112 due to the intermittent opening and closing of the communicating portions of the flow paths 111 and 112 by the valve body 115. Due to the energy of this pulsation, the pipe connected to the output port 103 and the external device connected to one end thereof vibrate, and the vibration propagates from the contact portion with the pipe and the external device to the outside, causing a problem.

  Therefore, when this conventional solenoid valve is used, a chamber is provided in the middle of the piping. FIG. 7 shows a configuration diagram of a conventional fuel evaporative emission control device using a solenoid valve, in which 130 is a canister in the fuel evaporative gas emission control device, and 140 is a pipe 150 connecting the solenoid valve 100 and the canister 130. It is the chamber provided in.

Next, the operation will be described.
When the engine is operated, the intake manifold becomes negative pressure. When the solenoid valve 100 is opened, evaporative gas is supplied from the canister 130 through the chamber 140 and the solenoid valve 100 to the intake manifold. However, if this supply amount is not appropriate, the engine operation will be adversely affected. Therefore, the solenoid valve 100 is intermittently (duty) controlled by a control signal from a control device (not shown). The operation sound and air flow sound of the solenoid valve 100 main body, which is generated by this intermittent opening and closing and propagates in the pipe, are attenuated by the chamber 140 and are not transmitted to the canister 130, thereby reducing the generation of resonance sound in the canister 130. Yes. At the same time, the vibration of the pipe and canister caused by the pulsation is reduced by attenuating the pulsation of the fluid flowing in the pipe by the chamber 140.

FIG. 8 shows the characteristics of the emitted sound with respect to the chamber installation position. FIG. 8A shows the case where the same frequency component as the natural frequency of the canister does not resonate in the pipe among the emitted sound propagating in the pipe. b) shows the case of resonance.
FIG. 9 is a characteristic diagram of the resonance vibration of the canister with respect to the chamber installation position. FIG. 9A shows a case where the same frequency component as the natural frequency of the canister does not resonate in the pipe among the emitted sound propagating through the pipe. , (B) shows the case of resonance.
The natural vibration frequency of the canister used in the evaluation is 850 Hz, and its wavelength is 40 cm. Therefore, the same frequency component (850 Hz in this case) of the emitted sound resonates in the pipe when the pipe length is an even multiple of a quarter wavelength of the wavelength, that is, an even multiple of 10 cm.

  As is clear from these figures, if this chamber 140 is provided at the node of the wave distribution in the pipe corresponding to FIGS. 8A and 8B, there is no effect of reducing the pulsation, and the abdomen of the wave distribution is not provided. If provided, there is an effect of reducing pulsation. Further, the wave distribution at both open ends of the pipe 150 connected to the output port 103 is antinode for all frequency components regardless of the presence or absence of resonance.

As described above, the conventional solenoid valve generates an operating sound and an air flow sound each time the flow path is opened and closed. When these sounds are released into the external device, the natural vibration frequency of the external device among the emitted sound components. The same frequency components resonate, and a malfunctioning old resonance occurs. Furthermore, depending on the length of the pipe connecting the solenoid valve and the external device, the emission sound itself resonates in the pipe. When resonance occurs, the emission sound is amplified and emitted to the external device, so that the resonance sound of the external device is further increased.
Further, every time the flow path is opened and closed, a pulsation is generated in the fluid, and the energy of the pulsation vibrates the piping connected to the solenoid valve and the external device, causing a problem.

  Therefore, when this solenoid valve is used, a chamber is provided in the middle of the pipe connecting the output port and the external device. However, regarding the resonance of the external device, the position where the chamber is provided is the wave of the emission sound in the hose. If it is not the abdomen, the reduction effect is small, and it is difficult to provide it in accordance with the position of the abdomen of resonance. In addition, providing a chamber in the middle of the piping has a disadvantage in terms of layout and cost.

  The present invention has been made to solve the above-described problems. A solenoid valve capable of reducing sound emitted from the solenoid valve main body and reducing canister resonance without providing a chamber in the middle of the piping. The purpose is to obtain. It is another object of the present invention to provide a solenoid valve that can reduce pulsation of fluid generated by opening and closing of the solenoid valve and reduce vibration of piping and canisters.

Solenoid valve according to the present invention, the energization of an input port pressure is supplied from the intake pipe, and an output port connected to the canister for temporarily adsorbing evaporative emissions from the fuel tank, the coil provided with a valve body at one end In a duty solenoid valve having a plunger that opens and closes a flow path that connects the input port and the output port in response to de-energization, the output port and the valve body are opened and closed to reduce discharge noise or pulsation emitted from the output port. And a chamber for introducing evaporative gas supplied from the output port side and leading out the evaporative gas to the opening / closing portion side by the valve body, which is discharged from the output port. It is provided at the belly part of the discharge sound and is provided integrally in the duty solenoid valve.

  According to the present invention, since the solenoid valve is configured by providing the chamber in the flow path from the input port to the output port in the housing, the chamber is positioned at the abdomen of pulsation caused by opening and closing of the flow path by the plunger, The effect of reducing pulsation can be obtained naturally and reliably. As a result, this pulsation is transmitted to the external device, and the resonance generated by resonating with the natural frequency of the external device can be reduced. In addition, since the chamber is integrated with the solenoid valve, there is no need to provide a separate and independent chamber in the middle of the piping as in the prior art, and the number of parts can be reduced and workability can be improved. Is obtained.

An embodiment of the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a longitudinal sectional view showing a solenoid valve according to Embodiment 1 of the present invention. In the figure, 1 is a resin housing provided with an input port (negative pressure application port) 2 and an output port 3, A resin cover 5a for housing the coil 5 is provided between the housing 1 and the cover 4 and is a magnetic (iron) plate that forms a magnetic path with the yoke 6 and the core 7, and 8 is a magnetic path with the plate 5a. Is a yoke of a U-shaped magnetic body (made of iron) that forms
Here, in the conventional example, the input / output port is arranged so that a force is applied in the direction in which the valve is closed by the negative pressure when the valve is closed. However, in this embodiment, the valve is closed by the negative pressure when the valve is closed. By applying a force in the opening direction, a smooth operation at the initial stage of valve opening is obtained. Moreover, the arrangement of the chamber chamber is made easy.

  9 is provided in a connector 10 for supplying power to the coil 5, a connector hole into which an external socket (not shown) is inserted, 11 a flow path communicating with the output port 3 formed in the housing 1, and 12 a housing 1 is a flow path that communicates with the input port 2 formed in 1, 13 is a pin that is attached by projecting a part of one core of the core 7, 14 is a plunger fitted outside the pin 13, and 15 is a plunger of the plunger 14. A valve body 16 provided at one end is contracted between the core 7 and the plunger 14, and a spring 17 that always closes the communication portion of the flow passages 11, 12 by bringing the valve body 15 into contact with the end face of the housing 1. Is a leaf spring provided on the plunger 14, and a seal member 18 is integrally provided on the peripheral edge thereof. Reference numeral 19 denotes a mounting seat for mounting the solenoid valve to an external device (not shown), 20 denotes a mounting bolt for mounting the mounting seat 19 to the external device, and 21 denotes a housing positioned between the output port 3 and the opening / closing portion by the valve body 15. 1 is a cover provided on one side of the chamber 21, and the cover 22 is ultrasonically welded to the housing 1.

Next, the operation will be described.
First, when the coil 5 is not energized from an external power source (not shown), the valve body 15 of the plunger 14 is pressed against the end surface of the housing 1 by the urging force of the spring 16 to close the communication portion of the flow paths 11 and 12. The communication between the input port 2 and the output port 3 is closed.

  Next, when the coil 5 is energized from the external power source through the connector pin 10a, a magnetic field is generated in the coil 5, and a magnetic path passing through the plate 5a, the core 7, the yoke 8, and the plunger 14 is formed. A force that attracts the core 7 and the plunger 14 is generated, and the plunger 14 moves as shown in FIGS. 2 to 3 against the urging force of the spring 16. For this reason, the valve body 15 is separated from the end face of the housing 1, opens the communication portion with the flow paths 11 and 12, and the input port 2 and the output port 3 communicate with each other. As a result, the fluid entering from the output port 3 is drawn to a negative pressure and passes through the flow paths 11 and 12 to the input port 2.

According to the first embodiment, since the chamber 21 is provided in the vicinity of the output port 3 in the housing 1 of the solenoid valve, the chamber 21 is provided in the abdomen of the emission sound emitted from the output port 3. Regardless of the pipe length, the emission sound reduction effect can be obtained. In addition, since the chamber is integrally provided in the solenoid valve, there is no trouble in work as in the case where a separate and independent chamber is provided in the middle of the piping as in the prior art, which is advantageous in terms of layout and cost. Thus, the number of parts can be reduced and workability can be improved .

Embodiment 2. FIG.
FIG. 4 is a block diagram showing a fuel evaporative emission control device to which the solenoid valve shown in the first embodiment is applied. In FIG. 4, 31 is a fuel tank, 32 is a separator provided in the passage 31a, and 33 is a pressure sensor for failure diagnosis, and performs failure diagnosis by detecting a pressure change due to fuel leakage while the vehicle is running. 34 is a canister connected to one end of the passage 31a, 35 is an air cut valve connected to the air inlet 34a of the canister 34 via an air hose 36, 37 is a passage connecting the outlet of the canister 34 and the intake pipe 38, Reference numeral 39 denotes a canister purge valve provided in the middle of the passage 37, and the solenoid valve shown in the first embodiment is used as the canister purge valve 39.

Next, the operation will be described.
The fuel evaporative gas evaporated from the fuel tank 31 passes through the passage 31a and is separated into a liquid phase and a gas phase in the separator 32. The liquid phase returns to the fuel tank 31 through the passage 31a, and the gas phase is sent to the canister 34 due to a pressure difference. I care.

  The evaporative gas sent to the canister 34 is temporarily adsorbed on the activated carbon in the canister 34 and supplied to the intake pipe 38 of the engine via the canister purge valve 39 when the operating condition is satisfied. The canister purge valve 39 receives a control signal from a control device (not shown), opens and closes the passage 37, and adjusts the purge amount of the evaporated gas from the canister 34 to the intake pipe 38.

  In this case, the evaporating gas supplied from the canister 34 to the canister purge valve 39 is pulsated by the opening / closing operation of the canister purge valve 39, and this pulsation is transmitted to the canister 34, and a resonance sound is generated in the canister 34 due to this pulsation. Become. However, according to the second embodiment, since the solenoid valve shown in the first embodiment is applied as the canister purge valve 39, the pulsation caused by the opening / closing operation of the canister purge valve 39 is a chamber provided in the abdomen thereof. Therefore, the pulsation transmitted to the canister 34 is reduced, and the resonance generated due to the pulsation is also reduced.

  FIG. 5 is a characteristic diagram of the transmission vibration with respect to the chamber volume. The white circle is the characteristic of the conventional device in FIG. It is a characteristic. As is apparent from this characteristic diagram, transmission vibration can be reduced by using the solenoid valve of the present invention as the canister purge valve 39. As a result, the resonance generated in the canister 34 due to this transmission vibration is naturally small.

  According to the second embodiment, since the solenoid valve provided with the chamber 21 in the vicinity of the output port 3 in the housing 1 is used as the canister purge valve 39, pulsation caused by opening and closing of the flow path can be reduced in the chamber 21. it can. As a result, the pulsation discharged to the pipe is reduced, and this pulsation is transmitted to the canister 34, so that no large resonance sound is generated even if it resonates with the natural vibration frequency of the canister 34.

It is a longitudinal cross-sectional view which shows the solenoid valve by Embodiment 1 of this invention. It is an enlarged view of the closed state of the valve body part of the solenoid valve by Embodiment 1 of this invention. It is an enlarged view of the open state of the valve body part of the solenoid valve by Embodiment 1 of this invention. It is a block diagram of the fuel evaporative gas discharge suppression device by Embodiment 2 of this invention to which the solenoid valve by Embodiment 1 of this invention is applied. It is a transmission vibration change characteristic view with respect to chamber volume change. It is a longitudinal cross-sectional view which shows the conventional solenoid valve. It is a block diagram of the fuel evaporative gas discharge | emission suppression apparatus to which the conventional solenoid valve is applied. It is the characteristic figure of the emitted sound with respect to a chamber installation position, (a) is a case where it is not resonating, (b) is a case where it is resonating. It is a characteristic figure of the resonance vibration of the canister with respect to a chamber installation position, (a) is not resonating, (b) is the case where it is resonating.

Explanation of symbols

2 input port, 3 output port, 5 coil, 11, 12 flow path, 14 plunger, 31 fuel tank, 34 canister, 38 intake pipe, 39 canister purge valve (solenoid valve).

Claims (3)

An input port to which pressure is supplied from the intake pipe, an output port connected to a canister that temporarily adsorbs evaporated gas from the fuel tank , a valve body at one end, and the input according to energization and de-energization of the coil In a duty solenoid valve having a plunger that opens and closes a flow path that communicates between the port and the output port, the output port and an opening / closing portion formed by the valve body to reduce a discharge sound or pulsation discharged from the output port. And a chamber for introducing the evaporative gas supplied from the output port side and leading the evaporative gas to the opening / closing portion side of the valve body, the chamber being discharged from the output port And provided integrally with the duty solenoid valve. Duty solenoid valve for a fuel evaporative emission control system according to. 2. The duty solenoid valve for a fuel evaporative emission control device according to claim 1, wherein the plunger is constructed in a direction in which the valve is opened by negative pressure. The duty solenoid valve for a fuel evaporative emission control device according to claim 1 or 2, wherein the chamber has a volume of at least 6 cc or more.

Images