JP4230338B2 - Electromagnetic relief valve and system operation and shutdown method - Google Patents

Description

  The present invention relates to an electromagnetic relief valve that communicates or blocks an inflow side and an outflow side of a valve.

Conventionally, for example, in a vehicle using a gasoline engine that directly injects fuel into a cylinder of an engine, fuel having a very high pressure of 12 [MPa] is injected from the injector. In such a direct injection gasoline system, fuel is sucked up from a fuel tank by a fuel pump, boosted by a high pressure pump, supplied to a delivery (pipe), and injected from an injector. Note that a (mechanical) relief valve is provided for returning the fuel from the delivery to a return path such as a fuel tank in case the pressure of the fuel in the delivery becomes abnormally high.
In the conventional direct-injection gasoline system, when the engine is stopped, the pressure of the fuel remaining in the delivery gradually increases due to the remaining heat, and when the pressure exceeds a predetermined pressure, the pressure exceeds the predetermined pressure. Reached fuel is returned from the (mechanical) relief valve to the return path.
During the operation of the engine, fuel is injected from the injector as needed, so the fuel pressure drop due to the drop in the amount of fuel in the delivery is compensated by the fuel supply from the high pressure pump, and the fuel pressure in the delivery is about 12 [MPa]. Is kept constant. However, since the fuel is not injected while the engine is stopped, the fuel pressure does not decrease, and the fuel pressure gradually increases due to residual heat. For example, in a (mechanical) relief valve, the fuel in the delivery is returned to the return path when the pressure is 14 [MPa] or more.

  During the period from when the engine is stopped until the temperature drops to a predetermined temperature, the injector is under higher pressure than during operation, and the amount of fuel leakage from the injector valve body into the engine cylinder increases. Emissions get worse at startup. Preferably, the fuel in the delivery may be forcibly returned to the return path while the engine is stopped. In other words, when the engine is running (during system operation), the delivery side (the inflow side where the fluid flows into the valve) and the return path side (the outflow side where the fluid flows out from the valve) are shut off and the engine is stopped ( Provide an electromagnetic relief valve (normally open type solenoid valve) that communicates between the delivery side and the return path side when the system is not running), or the delivery side and return path side when the engine is running. When the engine is stopped, an electromagnetic relief valve (normally closed type solenoid valve) that communicates between the delivery side and the return path while being energized can be provided together with the (mechanical) relief valve (the electromagnetic relief valve Just add).

Note that various electromagnetic valves have been conventionally proposed as the normal open type or normal close type electromagnetic valve described above (see, for example, Patent Document 1).
JP-A-8-93957

However, the conventional normally open type solenoid valve needs to supply current constantly during the operation of the system, and the current consumption is very large, and the normally closed type solenoid valve always has a period during which the system is stopped. It is necessary to supply a current, which is also not preferable because the current consumption is very large.
Further, since it is necessary to maintain a very high pressure of 12 [MPa] at the time of closing, the elastic member (spring or the like) that biases the valve body requires a very high biasing force. Naturally, the electromagnetic force attracted in the direction opposite to the biasing force of the elastic member also requires a very high electromagnetic force, and a coil that can continuously flow the required current for several tens of seconds or more can be realized on the heating surface. It is very difficult.
The present invention was devised in view of such points, and with low current consumption, the inflow side and the outflow side of the valve can be reliably shut off during the operation of the system, while the system is stopped. An object of the present invention is to provide an electromagnetic relief valve capable of reliably communicating the inflow side and the outflow side of the valve.

As means for solving the above-mentioned problems, the first invention of the present invention is an electromagnetic relief valve as described in claim 1.
The electromagnetic relief valve according to claim 1 includes a valve body, a valve seat, an elastic member, and a coil, and includes an urging force by the elastic member, an attractive force by energizing the coil, and the valve body. This is an electromagnetic relief valve that can be in either a valve-open state or a valve-closed state with a suction force based on the pressure difference of the fluid that controls the flow with the valve seat.
The direction of the urging force by the elastic member is set to the valve opening direction in which the electromagnetic relief valve is opened, and the direction of the suction force by energizing the coil is the state in which the electromagnetic relief valve is opened. The direction of the attraction force due to the pressure difference is set to the valve closing direction in which the electromagnetic relief valve is closed.

In the electromagnetic relief valve described in the present embodiment, the closing attractive force is generated when the differential pressure between the inflow side pressure and the outflow side pressure is equal to or higher than the first predetermined pressure.

The second invention of the present invention is an electromagnetic relief valve as set forth in claim 2 .
An electromagnetic relief valve according to a second aspect is the electromagnetic relief valve according to the first aspect, wherein the fluid having a predetermined pressure flowing in from a gap between the valve body and the valve seat in an opened state is the valve seat. The gap is set such that a suction force for sucking the valve body in the valve closing direction based on a pressure difference generated by a flow discharged from the valve is larger than a biasing force in the valve opening direction by the elastic member. Is set.

A third invention of the present invention is a system operation and stop method as described in claim 3 .
The system operation and stop method according to claim 3 is a system operation and stop method in a system that controls the flow of the fluid using the electromagnetic relief valve according to claim 1 or 2 .
In the operating state of the system, by supplying a fluid of a predetermined pressure to the system without energizing the coil, the valve body is moved in the valve closing direction and the electromagnetic relief valve is maintained in the valve closing state . To do.
If the state from the operating state of the system in a stopped state of the system transitions to stop the supply of fluid of the predetermined pressure, the move in the opening direction of the valve body by energizing the coil electromagnetic relief The valve is maintained open and the fluid is drained from the system.
Furthermore during the stop state continues for the system, the suction force of the valve closing direction by the pressure difference continues to energization of the coil to the smaller than the urging force in the valve opening direction, then to the coil stop of energization, said to maintain the electromagnetic relief valve to an open state by the urging force of the elastic member is a method.

The electromagnetic relief valve according to claim 1 is urged in an opening direction by an urging force of an elastic member, for example, to maintain an open state or a closed state, and is energized to the coil in a direction opposite to the urging force of the elastic member. Unlike a conventional solenoid valve that attracts in a certain closing direction, it is energized in the opening direction by the biasing force of the elastic member, and the coil is attracted in the opening direction that is the same direction as the biasing force of the elastic member. Further, the pressure difference due to the fluid is used to move the valve body in the closing direction . For this reason, when driving in the opening direction, once the coil is energized to the open state, the open state can be maintained by the urging force of the elastic member even if the energization to the coil is stopped thereafter. For this reason, the current consumption of the coil can be further reduced.

The electromagnetic relief valve according to claim 1 utilizes a differential pressure between the pressure on the inflow side and the pressure on the outflow side. When the operation of the system is started and the pressure on the inflow side increases, the electromagnetic relief valve is automatically closed. Therefore, when the system is stopped (open state), the system operation is started, the pressure on the inflow side rises, and when the differential pressure exceeds the first predetermined pressure, the system automatically closes. There is no current consumption inside.
In addition, if the system operation is stopped while the system is in operation (closed state), if the coil is energized and opened, and the differential pressure between the inflow side and the outflow side is almost eliminated, the valve body is an elastic member. Therefore, even if the supply of current is stopped, the open state can be maintained.
Therefore, the inflow side and the outflow side can be reliably shut off (closed state) while the system is operating, and the inflow side and outflow side can be reliably communicated (open state) while the system is stopped. Is a period from when the coil is energized after the system is stopped until the pressure difference between the inflow side and the outflow side is almost eliminated. For example, in a direct injection gasoline system, although it depends on the opening area when the electromagnetic relief valve is opened, it is about several tens to several hundreds [ms] and can be sufficiently realized.

According to the electromagnetic relief valve of the second aspect , the valve body is closed by the differential pressure by setting the gap between the valve body and the valve seat to an appropriate value with respect to the biasing force of the elastic member. Therefore, it is possible to easily adjust the suction force to be automatically sucked, and to easily realize a structure corresponding to the differential pressure of the system.

Further, according to the operation and stop method system according to claim 3, with the electromagnetic relief valve according to claim 1 or 2, and the outflow side reliably inflow side without the system operation that consumes current (Closed state) can be maintained to maintain the high pressure state on the inflow side, and the inflow side and the outflow side are communicated (open state) with low current consumption when transitioning from the system operation state to the stop state. The pressure on the inflow side can be sufficiently reduced. Further, while the system is stopped, the inflow side and the outflow side can be reliably communicated (opened) without consuming current, and the increase in pressure on the inflow side can be suppressed.

The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a fuel system path of a direct injection gasoline system provided with an electromagnetic relief valve 80 of the present invention.
● [Fuel system route (Fig. 1)]
Fuel (in this example, gasoline) is stored in the fuel tank T, and the pressure in the fuel tank T is approximately atmospheric pressure. A fuel pump 10 is provided in the fuel tank T, and the fuel pump 10 discharges the sucked-up fuel toward the pressure regulator 20. The pressure regulator 20 maintains the fuel pressure (hereinafter referred to as fuel pressure) in the pipe to the spill valve 30 at a constant pressure (for example, 0.3 [MPa]), and returns the fuel exceeding the pressure into the fuel tank T.
The fuel that has passed through the spill valve 30 is pressurized to about 12 [MPa] by the high pressure pump 40, passes through the check valve 50, and reaches the delivery 60. The delivery 60 is filled with high-pressure fuel of about 12 [MPa].

The delivery 60 is provided with an injector 70 corresponding to each cylinder of the engine, and each injector 70 injects fuel based on a drive signal from the controller C.
The delivery 60 is also provided with a (conventional mechanical) relief valve 90 and an electromagnetic relief valve 80 (of the present invention). The relief valve 90 and the electromagnetic relief valve 80 return the fuel to the upstream side of the pressure regulator 20 via the pipe Hr (may be returned to the fuel tank T).
(Conventional mechanical type) The relief valve 90 allows the delivery 60 and the pipe Hr to be connected when the fuel pressure in the delivery 60 becomes abnormally high (for example, 14 [MPa] higher than 12 [MPa]). The fuel is caused to flow from the delivery 60 to the pipe Hr. The relief valve 90 shuts off the delivery 60 and the pipe Hr when the fuel pressure in the delivery 60 is not abnormally high.
The electromagnetic relief valve 80 can cause the delivery 60 and the pipe Hr to communicate with each other by a drive signal from the controller C, and the fuel pressure in the delivery 60 rises so that the differential pressure with respect to the pipe Hr is a first predetermined pressure. When the pressure exceeds the pressure (for example, 0.5 to 1 [MPa] or more), the delivery 60 and the pipe Hr are automatically shut off.

● [Structure of electromagnetic relief valve (Figs. 2 and 3)]
Next, the structure of the electromagnetic relief valve 80 will be described with reference to FIGS.
The outer shape of the electromagnetic relief valve 80 is formed by an inflow side case 83a, an outflow side case 83b, and a coil cover 85a.
In the electromagnetic relief valve 80, the inflow side case 83 a is inserted into an attachment hole provided in the delivery 60, and is fixed to the delivery 60 with a screw B via a bracket 84. The gap between the inflow side case 83 a and the mounting hole provided in the delivery 60 is sealed with an O-ring 82.
The valve 87 and the valve body 88 are connected by welding or the like, and these can move together in the Z-axis direction. The core 86 is fixed at the illustrated position, and a non-magnetic portion 86a is provided on the outer peripheral portion of the opposing surface of the core 86 and the valve 87. Further, the core 86 and the valve 87 are provided with through holes through which the fuel flowing in from the inflow side case 83a passes in the direction of the outflow side case 83b.

The valve body 88 is opposed to a through-hole provided in the valve seat portion 89, and when the valve body 88 comes into contact with the valve seat portion 89 (when moving in the left direction in FIG. 2), the electromagnetic relief valve 80 is disposed inside the delivery 60. Shut off the pipe Hr. Hereinafter, the moving direction in this case is referred to as a “closing direction”.
On the contrary, when the valve body 88 is separated from the valve seat portion 89 (when moving in the right direction in FIG. 2), the electromagnetic relief valve 80 communicates the inside of the delivery 60 and the pipe Hr. Hereinafter, the moving direction in this case is referred to as an “opening direction”.
The valve 87 is biased in the opening direction by an elastic member S (spring or the like). When the coil 85 is further energized, the valve 87 (and the integrated valve body 88) is sucked in the opening direction (the direction of the core 86). The electromagnetic relief valve 80 shown in the present embodiment is characterized in that it has a structure in which it is urged in the opening direction by the elastic member S and sucked by the coil 85 in the same opening direction. What is used for the remaining force to move in the closing direction uses the fuel pressure in the delivery 60 (see FIG. 3D).

When the valve body 88 and the valve seat portion 89 are separated (in the open state), the fuel in the delivery 60 flows in from the Fin direction, passes through the filter 81, and flows into the inflow side case 83a. The inflowing fuel passes through the through holes of the core 86 and the valve 87 and is filled into the space D (see FIG. 4A) in which the elastic member S is accommodated. Further, the fuel flows into the through hole (space R (see FIG. 4A)) of the valve seat portion 89 from the gap g between the valve body 88 and the valve seat portion 89, and flows out from the outflow side case 83b in the Fout direction.
Here, FIGS. 3A and 3B show examples of the structure of the valve body 88 and the valve seat portion 89. In the open state, the valve body 88 is in contact with the claw 89a of the valve seat 89, but the fuel is a gap between the claw 89a and the valve body 88 (see the dotted arrow in FIG. 3B), and a gap g ( 3 (A)) and can flow into the through hole (space R). The inner diameter r of the claw 89a is substantially constant in the Z-axis direction, and the valve body 88 is movable in the Z-axis direction while being inscribed in the claw 89a.

Next, the operation in which the valve body 88 is sucked in the closing direction by the fuel pressure in the delivery 60 will be described with reference to FIG.
The valve body 88 is located at the boundary between the two spaces of the space D and the space R. The space D is a space in which the elastic member S in FIG. 2 is accommodated, and this space D is always in communication with the inside of the delivery 60. The space R is a through hole of the valve seat portion 89 in FIG. 2, and this space is always in communication with the pipe Hr.
In the open state, when there is almost no differential pressure between the space D and the space R, no force is generated to suck the valve body 88 in the closing direction. However, when the pressure in the space D increases in the open state (the pressure in the space D> the pressure in the space R) and the differential pressure between the space D and the space R becomes equal to or higher than the first predetermined pressure, the valve body 88 is moved to the low pressure side. That is, a force for sucking in the closing direction is generated. Then, the urging force by the elastic member S that urges the valve body 88 in the opening direction by the suction force that moves the valve body 88 in the closing direction by the differential pressure equal to or higher than the first predetermined pressure. Set to be larger than

As a result, when the fuel pressure in the delivery 60 rises and exceeds the first predetermined pressure, the valve body 88 is automatically sucked in the closing direction.
In the conventional normal open type or normal close type solenoid valve, the direction of the urging force by the elastic member S and the direction of the electromagnetic force by the coil are set in opposite directions, and the valve body is moved in the opening direction in one direction. The valve body is moved in the closing direction in the other direction (see FIG. 3C).
However, in the electromagnetic relief valve 80 shown in the present embodiment, the direction of the urging force by the elastic member S and the direction of the electromagnetic force by the coil are the same direction, and both move the valve body in the opening direction. The force for moving the valve body in the closing direction is a suction force due to the differential pressure of the fluid (in this case, the pressure (fuel pressure) in the delivery 60 and the pressure difference in the pipe Hr) (see FIG. 3D). ).

● [Operation of electromagnetic relief valve (Figs. 4 and 5)]
Next, the operation of the electromagnetic relief valve 80 shown in the present embodiment will be described with reference to FIGS. 4A shows a cross-sectional view of the vicinity of the valve body 88 in the open state, and FIG. 4B shows a cross-sectional view of the vicinity of the valve body 88 in the closed state. FIG. 5 is a schematic diagram for explaining the force for driving the valve body 88 in the opening direction or the closing direction.

[System stopped state (1)]
While the system (in this case, the engine) is stopped, the valve body 88 is urged by the elastic member S in the opening direction, and a gap g is formed between the valve body 88 and the valve seat portion 89 (see FIG. 4 (A)). Therefore, the fuel pressure in the delivery 60 on the inflow side (the fuel pressure in the space D) is 0.3 [MPa] that is substantially the same as the fuel pressure in the pipe Hr on the outflow side (the fuel pressure in the space R), and there is almost no differential pressure. State. For this reason, it is not necessary to energize the coil 85, and the following relational expression is established in FIG.
Biasing force Fs by elastic member S> Suction force Fp by differential pressure (differential pressure = nearly zero)
Thereby, the electromagnetic relief valve 80 is maintained in an open state (FIG. 4A).

[Transition from system stop state to operation state (2)]
When the operation of the system is started from the system stop state of (1) above, the fuel pressure on the inflow side (delivery 60) (the fuel pressure in the space D) is rapidly increased (increased toward 12 [MPa]) by the high pressure pump 40. A differential pressure with respect to the space R (about 0.3 [MPa]) is generated. Here, when the differential pressure becomes equal to or higher than the first predetermined pressure, the valve body 88 is sucked in the closing direction to be in the closed state (FIG. 4B), and the valve body 88 and the valve seat portion 89 come into contact (see FIG. 4). The gap g in (A) is equal to the gap gb in FIG. 4B).
The fluid (in this case, fuel) flows from the space D through the gap g between the valve body 88 and the valve seat 89 due to the differential pressure, and reaches the space R. At this time, in the suction area ga near the gap g, the suction force for sucking the valve body 88 increases as the fluid velocity v (not shown) of the fluid increases. (From Bernoulli's theorem, P + ρv ² * 1/2 + ρgh = constant (P: pressure, ρ: fluid density, v: fluid velocity, g: gravitational acceleration, h: height from the reference position))
Here, in order to increase the fluid velocity v when the differential pressure between the space D and the space R is the first predetermined pressure, the gap g may be appropriately reduced. In the present embodiment, the gap g is set to 50 to 60 [μm]. Note that the size of the gap g is larger than the mesh diameter of the filter 81 to prevent clogging.
As a result, the fluid velocity v at which the fluid (in this case, the fuel) flowing with the differential pressure between the space D and the space R generates the suction force Fp that sucks the valve body 88 by the gap g set appropriately. Bigger than. For this reason, the following relational expression is established in FIG.
Energizing force Fs by elastic member S <attraction force Fp by differential pressure (differential pressure ≧ first predetermined pressure)
As a result, the electromagnetic relief valve 80 is in a closed state (FIG. 4B) (this is the same phenomenon as when the plug is brought close to the hole and the plug is sucked into the hole when bath water is being drained). Thus, in the electromagnetic relief valve 80 of the present embodiment, the suction force of the closing direction driving means that drives the valve body 88 in the closing direction is the first predetermined difference between the inflow side pressure and the outflow side pressure. It has a structure that occurs when pressure is exceeded. In this case, the coil 85 is not energized.

[System operation continues (3)]
In the state where the operation of the system is continued from the state (2), the inside of the delivery 60 (space D) is maintained at about 12 [MPa], and the inside of the pipe Hr (space R) is about 0.3 [MPa]. The electromagnetic relief valve 80 is maintained in the closed state (FIG. 4B) since the state of the first predetermined pressure or more is maintained.

[State transition from system operation state to stop state (4)]
When the system is shifted from the state (3) to the stop state, the inside of the delivery 60 (space D) is maintained at about 12 [MPa], and the inside of the pipe Hr (space R) is about 0.3 [MPa]. The electromagnetic relief valve 80 is maintained in the closed state (FIG. 4B). If this state is left as it is, the fuel temperature in the delivery 60 (space D) gradually rises due to residual heat of the system (engine) and the fuel pressure gradually rises. The mechanical) relief valve 90 operates to connect the delivery 60 and the pipe Hr.
However, it is not preferable to apply a fuel pressure of 14 [MPa] to the injector 70 because the amount of fuel leakage from the valve body of the injector 70 increases. Therefore, after the system is stopped, before the fuel pressure rises due to residual heat or the like, the coil 85 of the electromagnetic relief valve 80 is energized for a predetermined time to open the electromagnetic relief valve 80 (FIG. 4A). It is only in this case that the electromagnetic relief valve 80 consumes current. In this case, the following relational expression is established in FIG.
“Biasing force Fs by elastic member S + electromagnetic force Fc by coil 85”> Attraction force Fp by differential pressure (differential pressure = system maximum pressure)
Thereby, the electromagnetic relief valve 80 will be in an open state (FIG. 4 (A)).

When the electromagnetic relief valve 80 is opened, the fuel flows at a stretch from the inflow side (delivery 60 (space D) side) to the outflow side (piping Hr (space R) side) due to the differential pressure. For example, when the capacity of the delivery 60 is about 50 [cc], the energization time to the coil 85 is sufficient to be about several tens to several hundreds [ms] although it depends on the opening area when the electromagnetic relief valve 80 is opened. . In a short time of several tens to several hundreds [ms], it is possible to flow a large current for attracting the valve body 88 attracted in the closing direction with a large differential pressure in the opening direction by electromagnetic force. Realizing the coil 85 is relatively easy.
When the differential pressure between the space D and the space R in the vicinity of the valve body 88 becomes less than a second predetermined pressure (for example, 0.5 [MPa]) by energization of several tens to several hundreds [ms], the valve body 88 is an elastic member. It is urged in the opening direction by the urging force of S, and the open state (FIG. 4A) is maintained even when the energization to the coil 85 is stopped. In this case, the following relational expression is established in FIG.
Biasing force Fs by elastic member S> Suction force Fp due to differential pressure (differential pressure <second predetermined pressure)
Here, even if the fuel pressure in the delivery 60 gradually increases due to residual heat of the engine or the like, since the increase is gentle, no differential pressure is generated until the valve body 88 is moved in the closing direction. Therefore, in the subsequent system stop state, the electromagnetic relief valve 80 maintains the open state (FIG. 4A) (returns to the state of (1) above).

In the present embodiment described above, the energization time to the coil 85 is set to “predetermined time”, but the fuel pressure (fuel pressure) in the delivery 60 is monitored by the controller C, and the fuel pressure becomes less than the second predetermined pressure. Alternatively, the controller C may be energized. “Energizing for a predetermined time” is the same as “energizing until the differential pressure between the pressure on the outflow side and the pressure on the inflow side is less than the second predetermined pressure”.
As described above, the electromagnetic relief valve 80 shown in the present embodiment can reliably shut off the inflow side and the outflow side of the electromagnetic relief valve 80 during operation of the system with a small current consumption. During stopping, the inflow side and the outflow side of the electromagnetic relief valve 80 can be reliably communicated.

The electromagnetic relief valve 80 of the present invention is not limited to the appearance and structure described in the present embodiment, and various modifications, additions and deletions can be made without changing the gist of the present invention.
The electromagnetic relief valve described in the present embodiment can be used in various systems other than the fuel system of a vehicle of a direct injection gasoline system.
The numerical values and the like used in the description of the present embodiment are examples, and are not limited to these numerical values and the like.
Further, the above (≧), the following (≦), the greater (>), the less (<), etc. may or may not include an equal sign.

It is the schematic which shows the path | route of the fuel system of the direct injection gasoline system which provided the electromagnetic relief valve 80 of this invention. It is a figure explaining the structure of the electromagnetic relief valve. It is a figure explaining the detail of the structure of the valve body 88 and the valve seat part 89. FIG. FIG. 6 is a diagram for explaining the operation of the electromagnetic relief valve 80. It is a schematic diagram for demonstrating the force which drives the valve body 88 to an opening direction or a closing direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel pump 20 Pressure regulator 30 Spill valve 40 High pressure pump 50 Check valve 60 Delivery 70 Injector 80 Electromagnetic relief valve 81 Filter 85 Coil 86 Core 87 Valve 88 Valve body 89 Valve seat part 90 (Mechanical) Relief valve C Controller S Elasticity Member g Clearance T Fuel tank

Claims (3)

A valve body, a valve seat, an elastic member, and a coil;
The valve is opened or closed by an urging force by the elastic member, a suction force by energizing the coil, and a suction force based on a pressure difference of a fluid that controls a flow between the valve body and the valve seat. An electromagnetic relief valve that can be in either state,
The direction of the urging force by the elastic member is set to a valve opening direction for opening the electromagnetic relief valve,
The direction of the attractive force by energizing the coil is set to the valve opening direction that opens the electromagnetic relief valve,
The direction of the suction force due to the pressure difference is set in a valve closing direction in which the electromagnetic relief valve is closed.
An electromagnetic relief valve characterized by that. The electromagnetic relief valve according to claim 1 ,
Said fluid having a predetermined pressure that has flowed from the gap between the valve body and the valve seat in the open state is based on a pressure difference generated by the flow discharged from the valve seat, to suck the valve body in the valve closing direction The gap is set so that the suction force is larger than the urging force in the valve opening direction by the elastic member,
An electromagnetic relief valve characterized by that. A system operation and shutdown method in a system for controlling the flow of the fluid using the electromagnetic relief valve according to claim 1, comprising:
In the operating state of the system, by supplying a fluid of a predetermined pressure to the system without energizing the coil, the valve body is moved in the valve closing direction and the electromagnetic relief valve is maintained in the valve closing state . And
If the state from the operating state of the system in a stopped state of the system transitions to stop the supply of fluid of the predetermined pressure, the move in the opening direction of the valve body by energizing the coil electromagnetic relief Maintaining the valve open and draining the fluid from the system;
Furthermore during the stop state continues for the system, the suction force of the valve closing direction by the pressure difference continues to energization of the coil to the smaller than the urging force in the valve opening direction, then to the coil stop of energization, said to maintain the electromagnetic relief valve to an open state by the biasing force by said elastic member,
A method for operating and stopping the system.

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