JPH0861162A - Evaporated fuel control device for automobile - Google Patents

Abstract

PURPOSE: To shorten feed oil time by putting the inside of a canister and the inside of a fuel tank under low pressure at the feed oil time in fuel control where a check valve to open when the inside of the canister is put under high pressure is arranged in the canister. CONSTITUTION: A check valve 28 to open when the inside of a canister is raised to prescribed pressure, is provided, and a breather valve 15 is provided. The breather valve 15 is controlled so as to be opened and closed by differential pressure between internal pressure of the canister 5 and internal pressure of a feed oil pipe 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel vapor control system for an automobile, and more particularly to a fuel vapor control system equipped with a canister for adsorbing and collecting the fuel vapor from a fuel tank. Related to shortening device.

[0002]

2. Description of the Related Art Conventionally, when fuel in a fuel tank mounted on an automobile is vaporized, the vaporized fuel is temporarily adsorbed and collected in order to prevent the vaporized fuel from being released to the atmosphere.
Some are equipped with a canister that supplies power to the engine when the engine is operating.

As an evaporative fuel control device equipped with such a canister, the one shown in FIG. 5 is conventionally known, and this device will be described. When the engine is stopped, the fuel in the fuel tank 101 evaporates and the fuel tank 1
When the pressure in the gas phase portion 102 in 01 increases, the pressure acts on the canister 104 through the evaporated fuel introducing passage 103 and also on the atmospheric port 113.

Further, when the engine is stopped and idling, the electromagnetic valve 106 is operated by the ECU 105.
The canister 104 because it is held closed.
The internal pressure acts on the diaphragm chamber 119 of the atmospheric valve 109 from the purge passage 107 through the conduit 108. Therefore, the atmospheric port 113 portion and the diaphragm chamber 119 have almost the same pressure, and the valve body 112 provided on the diaphragm 110 is closed by the urging force of the diaphragm spring 111.

When the inside pressure of the canister 104 is increased to a level equal to or higher than the closing load of the check valve 114 (about 150 mmH ₂ O), the check valve 114 is pushed open, and the air inside the canister 104 passes through the check valve 114 and the air introduction passage 115 to be an air cleaner. It flows to 116. By this flow, the evaporated fuel in the fuel tank 101 is adsorbed and collected by the adsorbent 117 made of activated carbon or the like in the canister 104, and only air is discharged from the check valve 114 to the air cleaner 116.

During engine operation while the vehicle is running, the electromagnetic valve 106 is held open by the ECU 105 and the negative pressure in the engine intake pipe 118 is reduced by the purge passage 107.
Through canister 104 and through diaphragm 108 into diaphragm chamber 119, respectively. At this time, since the pressure receiving surface of the diaphragm 110 is wider than the pressure receiving surface of the valve body 112, the diaphragm 110 is opened and the atmosphere port 113 is opened. Therefore, the atmosphere is the atmospheric port 11.
3 into the canister 104 and the purge passage 107
Flow from the engine intake pipe 118 to the engine intake pipe 118, the evaporated fuel adsorbed by the adsorbent 117 of the canister 104 is removed by the circulating air, and the engine intake pipe 118 is purged.

When refueling the fuel tank 101, the cap 120 is removed and the refueling gun 123 is inserted into the refueling pipe 121 to refuel. At this time, if the fuel is supplied while the engine is stopped or idling, the atmosphere valve 1 will operate as described above.
09 does not open, and the check valve 114 does not open until the canister 104, that is, the inside of the fuel tank 101 reaches a predetermined pressure (about 150 mmH ₂ O) or more.

[0008]

In the above conventional device, the evaporated fuel generated in the fuel tank during refueling and the evaporated fuel accumulated in the fuel tank 101 are pushed out by the refueled new fuel to cause the cap to disappear. In the case where the inner end 122 of the oil supply pipe 121 is reduced in diameter to make the gap between the oil supply gun 121 and the oil supply gun 123 small so that 120 is not released to the atmosphere, the oil supply speed becomes slower and the oil supply becomes slower. There is a problem that the time becomes long. That is, when refueling in the engine stopped state or the idling state, the atmosphere valve 109 is closed as described above in the engine stopped state or the idling state, and the check valve 1
Since 14 does not open up to a predetermined high pressure, when the gap between the inner end 122 of the fuel supply pipe and the fuel gun 123 is small as described above, the evaporated fuel generated by refueling and the accumulated fuel are accumulated in the fuel tank. Due to the evaporated fuel and the rise of the oil level, the inside of the fuel tank 101 is pressurized to a high opening pressure of the check valve 114. When the pressure in the fuel tank 101 increases in this way, the pressure suppresses the outflow of fuel from the refueling gun 123, the refueling speed becomes slower, and the refueling time becomes longer.

Therefore, the present invention is provided with a check valve that opens at a high pressure as described above, and makes the gap between the refueling pipe and the refueling gun small so as to prevent the evaporated fuel from being released from the refueling pipe to the atmosphere. It is a main object of the invention to provide an evaporated fuel control device for an automobile capable of shortening refueling time, and also to simplify the device and improve durability.

[0010]

SUMMARY OF THE INVENTION The present invention is to solve the above problems. A first invention according to claim 1 is provided with a check valve which opens to the atmosphere when the inside of the canister rises to a predetermined pressure. Check valve (2
Separately from 8), an atmospheric valve (15) is provided in the canister (5), and the atmospheric valve (15) is operated by using the internal pressure of the canister (5) and the internal pressure of the oil supply pipe (2) in the fuel tank (1) as an operation source. It is characterized in that it is controlled to be opened and closed and is opened to the atmosphere when the former pressure is higher than the latter pressure.

According to a second aspect of the present invention, a canister and a vapor phase portion of a fuel tank are connected to each other through an evaporative fuel introduction passage, and the canister is provided with a check valve that opens to the atmosphere when the internal pressure of the canister exceeds a predetermined level. An atmospheric valve is provided in the atmospheric port of the canister in addition to the above-mentioned check valve, and an atmospheric valve passage that connects the atmospheric valve and the purge passage is provided, and a pressure guiding passage is provided in the atmospheric valve passage through a three-way switching valve. Branching, communicating the other end of the pressure guiding passage with the oil supply pipe in the fuel tank,
The three-way switching valve (23) is switching-controlled in connection with opening and closing of the cap (3) of the oil supply pipe (2), and the purge passage (11) has the atmosphere valve passages (24, 26). It is characterized in that a purge control valve (12) is provided downstream of the communication part for shutting off when the engine is stopped or idling.

According to a third aspect of the present invention, in the atmosphere valve (15) according to the first or second aspect of the invention, a diaphragm chamber (18) and an atmosphere chamber (1) are provided by a diaphragm (16).
7) is a diaphragm valve partitioned into and a valve body (19) that comes into contact with and separates from the atmosphere port (14) of the canister is provided on the surface of the diaphragm (16) on the atmosphere side, and the diaphragm chamber (18) has the above-mentioned structure. Open the valve body (19) to the atmospheric port (14)
Equipped with a diaphragm spring (20) that biases to the side,
It is characterized in that the pressure in the oil supply pipe (2) in the fuel tank acts in the diaphragm chamber (18).

[0013]

According to the first aspect of the present invention, when the cap (3) of the fuel supply pipe (2) in the fuel tank (1) is removed to refuel, the pressure in the fuel tank (1) is boosted by the evaporated fuel, Further, the inside of the oil supply pipe (2) becomes almost atmospheric pressure.
Then, the increased pressure in the fuel tank (1) acts in the canister (5), and the pressure in the fuel supply pipe (2) which is close to the atmosphere acts on the atmosphere valve (15). When the value exceeds a predetermined value, the atmosphere valve (15) opens to the atmosphere, the pressure in the fuel tank (1) is released to the atmosphere through the canister (5), and no further pressure increase in the fuel tank (1) occurs. .

Therefore, by making the differential pressure for opening the atmosphere valve (15) extremely smaller than the opening pressure for the check valve (28), the internal pressure of the canister (5) is opened for the check valve (28). It can be maintained at a positive pressure that is extremely lower than the pressure.

As described above, by maintaining the inside of the canister (5) at an extremely low positive pressure, the inside of the fuel tank (1) can be maintained at the same low positive pressure, and the fuel outflow from the fuel gun (G) can be suppressed. The force is reduced, the refueling speed is increased, and the refueling time is shortened.

At times other than refueling, the refueling pipe (2) is closed by the cap (3), the pressure inside the atmosphere valve (15) and the inside of the canister (5) become almost the same pressure, and the atmosphere valve (15) closes. When the canister (5) is maintained in the above state and the internal pressure of the canister (5) rises to a predetermined pressure, the check valve (28) is opened to adsorb the evaporated fuel.

According to the second aspect of the present invention, when the engine is operating while the vehicle is running, the purge control valve (12) is opened, and the oil supply pipe (2) is closed by the cap (3) to switch between the three directions. The valve (23) is operated so that the atmosphere valve (15) communicates with the purge passage (11) and shuts off the pressure guiding passage (25), and the negative pressure in the purge passage (11) is changed to the atmosphere valve (1).
5) and the canister (5) are actuated to actuate the atmospheric valve (15)
Is opened, and the atmosphere is inhaled through the atmosphere valve (15) to perform a purging action.

During refueling with the engine stopped or idling, the purge control valve (12) is closed.
Also, by removing the cap (3), the three-way switching valve (23)
Is operated so that the atmospheric valve (15) communicates with the pressure guiding passageway (25) and shuts off the purge passageway. Further, by removing the cap (3), the inside of the oil supply pipe (2) becomes almost atmospheric pressure, and the pressure acts on the atmospheric valve (15) through the pressure guiding passageway (25). When fuel is supplied by the fuel gun (G) in this state, the pressure in the fuel tank (1) rises, the pressure in the canister (5) also rises, and the pressure in the atmosphere valve (15) becomes different from that in the atmosphere valve (15). (15) opens. This allows
Similar to the first aspect, the refueling speed is increased and the refueling time is shortened.

When the engine is stopped or idling except for refueling, the purge control valve (12) is closed, and the cap (3) closes the refueling pipe (2), so that the atmosphere valve (15) and the canister are closed as described above. (5) is communicated. As a result, the inside of the canister (5) and the atmospheric valve (15)
And the same pressure, the closed state of the atmospheric valve (15) is maintained, and when the pressure in the canister (5) rises to a predetermined pressure, the check valve (28) opens and the adsorbed action of the evaporated fuel is performed.

According to the third aspect of the present invention, in the non-lubricated state in which the oil supply pipe (2) is closed by the cap (3), the atmospheric pressure (15) and the canister (5) have substantially the same pressure. Therefore, the biasing force of the diaphragm spring (20) acts as the closing force of the atmospheric valve (15) as it is, and the sealing property of the atmospheric valve (15) is ensured. That is, in the method of sealing by the spring force that overcomes the positive pressure, there is a problem that the sealing performance is impaired by the engine vibration when the positive pressure and the spring force have a slight difference. By applying the same pressure, such a problem disappears.

[0021]

EXAMPLES Next, examples of the present invention shown in FIGS. 1 to 4 will be described. 1 is a fuel tank installed in the automobile, 2
Is an oil supply pipe provided in the fuel tank 1, and a cap 3 is detachably provided at the outer end thereof. Further, the inner end portion 4 of the fuel supply pipe 2 has a reduced diameter, and when the fuel gun G is inserted, the gap between the fuel gun G and the inner end portion 4 is reduced so that the evaporated fuel in the fuel tank 1 is The release from the oil supply pipe 2 to the atmosphere is suppressed.

A canister 5 is filled with an adsorbent 6 made of activated carbon or the like in its body. 7 is a canister 5
In the intake port provided in the above, the intake port 7 and the vapor phase portion 1a of the fuel tank 1 are communicated with each other by the evaporated fuel introducing passage 8.

Reference numeral 9 is a purge port provided in the canister 5, and the purge port 9 and the engine intake pipe 10 are connected by a purge passage 11. 12 is the purge passage 1
1 is a purge control valve including a solenoid valve provided in FIG. The purge control valve 12 includes a rotation sensor 13a for detecting engine rotation and an idle switch 13b (for example, when the engine is
A signal from a switch (which detects idle rotation of 00 rpm or less) is input to the ECU 13, and the ECU 13 causes the purge passage 1 to operate when the engine is operating in a vehicle running state.
1 is opened, and the purge passage 11 is controlled to be closed when the engine is stopped and when the engine is idling.

Reference numeral 14 is an atmospheric port provided in the canister 5. Reference numeral 15 is an atmosphere valve provided in the atmosphere port 14, and an atmosphere chamber 17 and a diaphragm chamber 18 are provided by a diaphragm 16.
And a valve body 19 for opening and closing the atmosphere port 14 on the surface of the diaphragm 16 on the atmosphere chamber side, and a diaphragm spring 20 for urging the diaphragm 16 toward the atmosphere port 14 in the diaphragm chamber 18. It is configured.

The atmospheric valve 15 has a positive pressure acting on the atmospheric port 14 higher than a positive pressure acting on the diaphragm chamber 18, and a differential pressure lower than an opening pressure of a check valve 28 described later. For example, the opening operation is set when the pressure becomes 20 mmH ₂ O or more.

The atmosphere chamber 17 is communicated with the air cleaner 22 by the atmosphere introduction passage 21 so that the atmosphere acts on the atmosphere chamber 17. Reference numeral 23 is a three-way switching valve composed of an electromagnetic valve, which is a first atmosphere valve passage 24 communicating with the diaphragm chamber 18 of the atmosphere valve 15 and a pressure guiding passage 25 communicating with the fuel tank 1 near the outer end of the fuel supply pipe 2. And the second atmosphere valve passage 26 communicating with the purge passage 11 on the upstream side of the purge control valve 12 are switched and controlled. Reference numeral 27 denotes a cap switch which is turned on when the cap 3 is removed and turned off when the cap 3 is attached. In the three-way switching valve 23, when the cap switch 27 is turned on, the first atmosphere valve passage 24 and the pressure guiding passage 25 communicate with each other as shown in FIG.
When the cap switch 27 is turned off and the cap switch 27 is turned off, the first atmosphere valve passage 24 and the second atmosphere valve passage 26 communicate with each other to shut off the pressure guiding passage 25, as shown in FIGS. 3 and 4. There is.

Reference numeral 28 denotes a check valve, which is opened when the pressure inside the fuel tank 1 rises above a predetermined pressure and the pressure acts inside the canister 5. As the predetermined pressure as the opening pressure of the check valve 28, for example, the positive pressure acting on the canister 5 is higher than the positive pressure acting on the atmosphere chamber 17, and the differential pressure thereof is about 150 mmH _2.
It is set to open when the temperature becomes O or higher.

Next, the operation of this embodiment will be described. When the engine is stopped or idling, and when oil is not supplied, the purge control valve 12 is closed and the cap switch 27 is off as shown in FIG. Reference numeral 23 is a state in which the first atmosphere valve passage 24 and the second atmosphere valve passage 26 are communicated with each other and the pressure guiding passage 25 is blocked. Further, the oil supply pipe 2 is closed by a cap 3.

In the state of FIG. 1 in which the oil level in the fuel tank 1 is lower than the inner end of the oil supply pipe 2 when the engine is stopped or idling, the gas phase portion 1 of the fuel tank 1 is
When a is boosted by the evaporated fuel, the pressure of the gas phase portion 1a acts in the canister 5 through the evaporated fuel introducing passage 8,
Further, it acts in the atmospheric port 14. At the same time, this pressure is applied to the purge passage 11, the second atmosphere valve passage 26, and the three-way switching valve 23.
And the first atmospheric valve passage 24 acts on the inside of the diaphragm chamber 18 of the atmospheric valve 15. Therefore, the atmospheric port 14
The inside and the inside of the diaphragm chamber 18 have almost the same pressure, and the urging load of the diaphragm spring 20 keeps the valve body 19 of the atmospheric valve 15 closed.

When the pressure in the gas phase portion 1a in the fuel tank 1 is increased to a positive pressure of 150 mmH ₂ O or more in the canister 5, the check valve 28 is pushed open, and the air in the gas phase portion 1a becomes the evaporated fuel. The air cleaner 22 passes through the introduction passage 8, the canister 5, the check valve 28, and the atmosphere introduction passage 21.
It flows in. By this flow, the evaporated fuel in the fuel tank 1 is adsorbed and collected by the adsorbent 6 of the canister 5.

Next, a description will be given of the case of refueling with the engine stopped or idling. Since the engine is stopped or idling, the purge control valve 12 is closed as shown in FIG. 3, as shown in FIG. Further, since the cap 3 is removed, the cap switch 27 is turned on as shown in FIG. 2, and the three-way switching valve 23 causes the first atmosphere valve passage 24 and the pressure guiding passage 2 to move.
5 and the second atmosphere valve passage 26 is shut off. When the refueling gun G is inserted into the refueling pipe 2 for refueling, the inner end portion 4 of the refueling pipe 2 and the refueling gun G are inserted.
The gap between the fuel tank 1 and
The evaporative fuel in a is suppressed from flowing into the fuel supply pipe 2 and the cap 3 is removed, so that the pressure in the vicinity of the outer end of the fuel supply pipe 2 becomes almost atmospheric pressure.

When refueling is started by the refueling gun G in such a state, the evaporated fuel generated by the refueling, the evaporated fuel remaining in the fuel tank 1, and the pressure in the fuel tank 1 due to the rise of the oil level. Rises, and the pressure in the canister 5 also rises through the evaporated fuel introduction passage 8.

On the other hand, since the vicinity of the outer end of the oil supply pipe 2 with which the pressure guiding passage 25 communicates is almost at atmospheric pressure as described above, the pressure guiding passage 25, the three-way switching valve 23, and the first atmosphere. The pressure acting on the diaphragm chamber 18 of the atmospheric valve 15 through the valve passage 24 is maintained at a pressure substantially close to the atmospheric pressure.

The pressure in the canister 5 rises due to refueling, and the pressure is higher than the total force of the positive pressure in the diaphragm chamber 18 and the urging load of the diaphragm spring 20, and the differential pressure is 20 mmH ₂ When the pressure becomes O or higher, the valve body 19 moves the diaphragm spring 20.
The air inside the canister 5 flows out from the atmospheric port 14 against the urging load of.

Therefore, the pressure in the canister 5 does not rise above this set pressure, and the pressure in the fuel tank 1 also does not rise above this set pressure. Thus, the fact that the pressure inside the fuel tank 1 can be maintained at a pressure lower than the opening pressure of the check valve 28 means that the fuel gun G can be controlled by the pressure inside the fuel tank 1.
The function of suppressing the outflow of fuel from the fuel tank can be reduced, and as a result, refueling can be performed smoothly and the refueling time can be shortened.

Further, at the time of refueling, the fuel tank 1
The vaporized fuel inside is adsorbed and collected by the adsorbent 6 of the canister 5 by the air flow. Next, the operation when the engine is running while the vehicle is running will be described.

During this operation, the cap 3 is attached and the cap switch 27 is in the off state.
As shown in FIG. 3, the three-way switching valve 23 connects the first atmosphere valve passage 24 and the second atmosphere valve passage 26, and shuts off the pressure guiding passage 25. Further, the purge control valve 12 is opened as shown in FIG. Therefore, the negative pressure generated in the engine intake pipe 10 acts on the canister 5 through the purge control valve 12 and the purge passage 11, and at the same time, the second atmosphere valve passage 26 branched from the purge passage 11 and the three-way switching valve 23 and Diaphragm chamber 18 of atmosphere valve 15 through 1 atmosphere valve passage 24
To work within.

At this time, since the diaphragm area on the diaphragm chamber 18 side is larger than the opening area of the atmosphere port 14, the force for sucking the diaphragm 16 toward the diaphragm chamber 18 side becomes larger than the suction force on the atmosphere port 14 side, and the valve The body 19 is opened against the urging load of the diaphragm spring 20, and thereafter, the open state of the valve body 19 is maintained by the atmosphere flowing into the canister 5 from the atmosphere port 14.

Then, the air sucked from the atmospheric port 14 flows through the canister 5 toward the purge port 9 and flows out from the purge port 9 into the engine intake pipe 10 through the purge passage 11 and the purge control valve 12. By this circulating air, the evaporated fuel adsorbed on the adsorbent 6 is released and is purged into the engine intake pipe 10 together with the air.

In the above embodiment, the atmospheric valve for purging the evaporated fuel in the canister and the atmospheric valve for letting out the air in the canister 5 at the time of refueling are shared by one atmospheric valve 15. However, in addition to the conventional air valve 109 for purging shown in FIG. 5, a second air valve that allows the air in the canister 5 to flow in at the time of refueling may be provided to shorten the refueling time.

That is, while using the configuration of FIG. 5 as it is, a second atmospheric valve consisting of a diaphragm valve is further provided, and the diaphragm chamber is connected to the vicinity of the cap of the fuel supply pipe in the fuel tank through the passage. The atmosphere chamber on the side opposite to the diaphragm chamber is connected to the canister by sandwiching the diaphragm.The diaphragm is equipped with a valve body that opens and closes the atmosphere port with one end open to the atmosphere.When refueling, the pressure in the gas phase of the fuel tank is reduced. Through the canister to the atmosphere chamber of the diaphragm valve, causing atmospheric pressure near the cap of the oil supply pipe to act on the diaphragm chamber, and the differential pressure opens the valve body to introduce the atmosphere into the canister and increase the pressure inside the canister. May be suppressed.

[0042]

As described above, according to the first aspect of the invention, in the canister provided with the check valve that opens when the internal pressure becomes high, the canister and the fuel tank are filled at the time of refueling. Can be set to a pressure lower than the opening pressure of the check valve, whereby the refueling speed can be increased and the refueling time can be shortened.

According to the second aspect of the present invention, the atmospheric valve for shortening the refueling time can be shared with the atmospheric valve for purging, and the structure is simple and the cost is low as compared with the case where the atmospheric valve is provided separately. .

According to the third aspect of the present invention, when the diaphragm valve is used as the atmosphere valve, the sealing property of the valve body is improved and the atmosphere valve can be reliably operated.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a communication state of each passage at the time of refueling in the engine stopped state or idling state.

FIG. 3 is a view showing a communication state of each passage when the engine is stopped or idling without oil supply.

FIG. 4 is a diagram showing a communication state of each passage when the engine is operating while the vehicle is running.

FIG. 5 is a system diagram of a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel tank 1a ... Gas phase part 2 ... Oil supply pipe 3 ... Cap 5 ... Canister 8 ... Evaporative fuel introduction path 11 ... Purge passage 14 ... Atmosphere port 15 ... Atmosphere valve 16 ... Diaphragm 17 ... Atmosphere chamber 18 ... Diaphragm chamber 20 ... Diaphragm spring 23 ... 3-way switching valve 24, 26 ... Atmosphere valve passage 25 ... Pressure passage 27 ...
Cap switch

Claims (3)

[Claims] 1. A check valve which opens to the atmosphere when the pressure inside the canister rises to a predetermined pressure,
An atmospheric valve is provided in the canister separately from the check valve, and the atmospheric valve is controlled to open and close by using the internal pressure of the canister and the internal pressure of the fuel supply pipe in the fuel tank as an operating source, and the atmospheric pressure is released when the former pressure is higher than the latter pressure. An evaporative fuel control device for an automobile, characterized in that it is opened in the. 2. A canister and a vapor phase portion of a fuel tank are connected by an evaporative fuel introduction path, and a canister is provided with a check valve that opens to the atmosphere when the internal pressure of the canister exceeds a predetermined value. In addition to the atmospheric valve, an atmospheric valve passage that connects the atmospheric valve and the purge passage is provided, and the pressure guide passage is branched through the three-way switching valve in the atmospheric valve passage. The end is communicated with the fuel supply pipe in the fuel tank, the three-way switching valve is switch-controlled in connection with opening and closing of the cap of the fuel supply pipe, and the purge passage is provided downstream of the communication portion of the atmosphere valve passage. An evaporative fuel control device for an automobile, which is provided with a purge control valve that is shut off when the engine is stopped or idling. 3. The atmospheric valve according to claim 1 or 2, wherein the atmospheric valve is a diaphragm valve divided by a diaphragm into a diaphragm chamber and an atmospheric chamber, and a valve that connects to and separates from the atmospheric port of the canister on the atmospheric side surface of the diaphragm. And a diaphragm spring for urging the valve body toward the atmosphere port side in the diaphragm chamber, and the pressure in the oil supply pipe in the fuel tank acts in the diaphragm chamber. .