JP2005155322A - Evaporated fuel treatment device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep influence of failure of one of control valves on function of a whole device to the minimum, in an evaporated fuel treatment device for an internal combustion engine including two control vales with different bore diameter disposed in parallel with each other to a passage connecting a fuel tank with the outside. <P>SOLUTION: If a first control valve 28 for controlling communication state of the fuel tank 10 with the outside fails, a control mode of a second control valve 29 which is disposed in parallel with the first control valve 28 is switched from a normal control mode to a control mode corresponding to the failure of the first control valve 28. Similarly, when the second control valve 29 fails, a control mode of the first control valve 28 is switched from a normal control mode to a control mode corresponding to the second control valve 29. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an evaporated fuel processing apparatus for an internal combustion engine, and more particularly to an evaporated fuel processing apparatus having two control valves having different diameters in parallel in a passage connecting a fuel tank and the outside.

2. Description of the Related Art Conventionally, there has been known an apparatus in which two control valves having different diameters are arranged in parallel in a passage connecting a fuel tank and the outside, and each control valve is selectively used according to the purpose. For example, in the apparatus described in Patent Document 1, a large-diameter oil supply valve and a small-diameter pressure release valve are arranged in parallel in a passage connecting a fuel tank and a canister. In this device, when the internal pressure of the fuel tank is high, the pressure release valve with a small diameter is first opened to lower the internal pressure of the fuel tank to a certain extent, and then the large diameter is released when the opening force becomes small due to the pressure drop. By opening the fuel supply valve, the time required for releasing the pressure of the fuel tank can be shortened.
JP 2001-206082 A Japanese Patent Laid-Open No. 7-208275

  However, in the above-described conventional apparatus, no consideration is given to handling when one of the control valves fails. In this device, each control valve is provided in accordance with the purpose, and if any one of them fails, the role of the failed control valve cannot be achieved. That is, the function of the entire apparatus is hindered by the failure of one control valve. For example, when the pressure release valve fails to close, not only the pressure release valve does not operate, but also the oil supply valve does not operate because the pressure in the fuel tank does not drop. For this reason, the evaporated fuel in the fuel tank cannot be extracted, and the tank internal pressure remains high.

  The present invention has been made to solve the above-described problems, and in a device having two control valves having different diameters in parallel in a passage connecting a fuel tank and the outside, the failure of one of the control valves. It is a first object of the present invention to provide an evaporative fuel processing apparatus that can minimize the influence of the above on the function of the entire apparatus.

  Moreover, since each control valve has a different purpose, there may be a difference in the frequency of use of the two control valves. In such a case, in the control valve that has not been used for a long time, the valve and the valve seat stick to each other, which may cause a closing failure of the control valve.

  Accordingly, the present invention provides an apparatus having two control valves having different diameters in parallel in a passage connecting the fuel tank and the outside, and is capable of preventing sticking due to the fact that one of the control valves is not used for a long period of time. A second object is to provide a fuel processor.

In order to achieve the first object, a first invention is an evaporated fuel processing apparatus for an internal combustion engine,
A fuel tank for storing fuel;
A first control valve for controlling a communication state between the fuel tank and the outside;
A second control valve provided in parallel with the first control valve and having a smaller diameter than the first control valve for controlling a communication state between the fuel tank and the outside;
First failure detection means for detecting a failure of the first control valve;
First control means for switching the control mode of the second control valve from a normal control mode to a control mode corresponding to the failure of the first control valve when the first control valve fails;
It is characterized by having.

In order to achieve the first object, the second invention is a fuel vapor processing apparatus for an internal combustion engine,
A fuel tank for storing fuel;
A first control valve for controlling a communication state between the fuel tank and the outside;
A second control valve provided in parallel with the first control valve and having a smaller diameter than the first control valve for controlling a communication state between the fuel tank and the outside;
Second failure detection means for detecting a failure of the second control valve;
Second control means for switching the control mode of the first control valve from a normal control mode to a control mode corresponding to the failure of the second control valve when the second control valve fails;
It is characterized by having.

In order to achieve the second object, a third invention is an evaporated fuel processing apparatus for an internal combustion engine,
A fuel tank for storing fuel;
A first control valve for controlling a communication state between the fuel tank and the outside;
A second control valve provided in parallel with the first control valve and having a smaller diameter than the first control valve for controlling a communication state between the fuel tank and the outside;
First measuring means for measuring a continuous closing time of the first control valve;
Third control for opening the first control valve instead of the second control valve when the second control valve opens when the continuous closing time of the first control valve exceeds a predetermined time Means,
It is characterized by having.

In order to achieve the second object, a fourth invention is an evaporated fuel processing apparatus for an internal combustion engine,
A fuel tank for storing fuel;
A first control valve for controlling a communication state between the fuel tank and the outside;
A second control valve provided in parallel with the first control valve and having a smaller diameter than the first control valve for controlling a communication state between the fuel tank and the outside;
Second measuring means for measuring the continuous closing time of the second control valve;
Fourth control for opening the second control valve instead of the first control valve when the first control valve opens when the continuous closing time of the second control valve exceeds a predetermined time Means,
It is characterized by having.

  In a fifth aspect based on the first aspect, when the first control valve is normal when the first control valve is closed, the first control valve opens when only the first control valve opens. 2 It is characterized by opening the control valve.

  In a sixth aspect based on the second aspect, the second control means is configured such that when the second control valve is in a closed state, if the second control valve is normal, only the second control valve is opened. One feature is that a control valve is opened.

  In a seventh aspect based on the fifth aspect, the first control means is configured so that the flow rate obtained by opening the second control valve is equal to the flow rate obtained when the first control valve is normally operated. The valve opening amount of the second control valve is controlled.

  In an eighth aspect based on the sixth aspect, the second control means is configured so that the flow rate obtained by opening the first control valve is equal to the flow rate obtained when the second control valve is normally operated. The valve opening amount of the first control valve is controlled.

  In a ninth aspect based on the seventh aspect, the first control means opens the second control valve for a time longer than the valve opening time during normal operation of the first control valve. It is a feature.

  In a tenth aspect based on the eighth aspect, the second control means opens the first control valve for a shorter time than the valve opening time during normal operation of the second control valve. It is a feature.

  In an eleventh aspect based on the seventh aspect, the first control means opens the second control valve at a cycle shorter than a control cycle during normal operation of the first control valve. It is said.

  In a twelfth aspect based on the eighth aspect, the second control means opens the first control valve at a cycle longer than a control cycle during normal operation of the second control valve. It is said.

  According to a thirteenth aspect, in the first aspect, the first control means always closes the second control valve when the first control valve fails to open.

  In a fourteenth aspect based on the second aspect, the second control means is configured such that when the second control valve fails to open, when the second control valve is normal, only the first control valve opens. It is characterized in that the opening amount of one control valve is controlled to be equal to or less than normal.

  According to the first invention, even if the first control valve fails, the second control valve functions as a substitute for the first control valve. Therefore, the influence of the failure of the first control valve on the function of the entire apparatus is minimized.

  According to the second invention, even if the second control valve fails, the first control valve functions as a substitute for the second control valve. Therefore, the influence of the failure of the second control valve on the function of the entire apparatus is minimized.

  According to the third invention, if the first control valve has not been used for a long time, the first control valve is used instead of the second control valve. Therefore, the first control valve is prevented from sticking due to not being used for a long time.

  According to the fourth invention, if the second control valve has not been used for a long period of time, the second control valve is used instead of the first control valve. Therefore, the second control valve is prevented from sticking due to not being used for a long time.

  According to the fifth aspect, even if the first control valve fails to close, the second control valve opens as a substitute for the first control valve. Therefore, the influence of the first control valve closing failure on the function of the entire apparatus is minimized.

  According to the sixth invention, even if the second control valve is closed, the first control valve opens as a substitute for the second control valve. Therefore, the influence of the closing failure of the second control valve on the function of the entire apparatus is minimized.

  According to the seventh aspect, since the same flow rate as that at the time of normal operation of the first control valve can be obtained by opening the second control valve, the entire device has substantially the same function at the time of normal operation of the first control valve. Can be obtained.

  According to the eighth invention, since the same flow rate as that at the time of normal operation of the second control valve can be obtained by opening the first control valve, the entire device has substantially the same function at the time of normal operation of the second control valve. Can be obtained.

  According to the ninth aspect, by opening the second control valve longer than the first control valve, it is possible to correct the shortage of the flow rate due to the small diameter, which is the same as during normal operation of the first control valve. Can be obtained.

  According to the tenth invention, by opening the first control valve shorter than the second control valve, it is possible to correct the excessive flow rate due to the large diameter, and the same as during normal operation of the second control valve. Can be obtained.

  According to the eleventh aspect, by opening the second control valve at a cycle shorter than that of the first control valve, it is possible to correct the shortage of flow rate due to the small diameter, and the normal operation of the first control valve. As much flow as the time can be obtained.

  According to the twelfth aspect, by opening the first control valve at a cycle longer than that of the second control valve, it is possible to correct the excessive flow rate due to the large diameter, and the normal operation of the second control valve. As much flow as the time can be obtained.

  According to the thirteenth aspect, by always closing the second control valve, it is possible to prevent the flow of the evaporated fuel from becoming excessive in a situation where the evaporated fuel always flows out due to an open failure of the first control valve. Thus, it is possible to minimize the influence of the open failure of the first control valve on the function of the entire apparatus.

  According to the fourteenth aspect of the present invention, when the first control valve is opened only when it is normal, the valve opening amount of the first control valve is controlled to be equal to or lower than that at the normal time so that the second control valve is always opened. In the situation where the evaporated fuel flows out, it is possible to prevent the flow rate of the evaporated fuel from becoming excessive, and the influence of the open failure of the second control valve on the function of the entire apparatus can be minimized.

Embodiment 1 FIG.
[Description of device configuration]
FIG. 1A is a diagram for explaining the configuration of the fuel vapor processing apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1A, the apparatus of this embodiment includes a fuel tank 10. The fuel tank 10 is provided with a tank internal pressure sensor 12 for measuring the tank internal pressure Pt. The tank internal pressure sensor 12 is a sensor that detects a tank internal pressure Pt as a relative pressure with respect to the atmospheric pressure and generates an output corresponding to the detected value. A liquid level sensor 14 for detecting the liquid level of the fuel is disposed inside the fuel tank 10.

  A vapor passage 20 is connected to the fuel tank 10 via ROV (Roll Over Valve) 16 and 18. The end portion of the vapor passage 20 communicates with the canister 26, and two sealing valves 28 and 29 are provided in parallel on the way. These block valves 28 and 29 are normally closed electromagnetic valves that are closed when not energized and are opened when a drive signal is supplied from the outside. The two block valves 28 and 29 have different calibers, one of the block valves 28 has a large diameter, and the other block valve 29 has a small diameter. Therefore, when the opening / closing control is performed with the same duty ratio, the flow rate of the gas flowing through one of the blocking valves 29 is larger than the flow rate of the gas flowing through the other blocking valve 28. Hereinafter, the block valve 28 having the larger diameter is referred to as a large flow valve 28, and the block valve 29 having the smaller diameter is referred to as a small flow valve 29. Sensors 91 and 92 for detecting the operation are attached to the large flow valve 28 and the small flow valve 29.

  The large flow valve 28 constitutes a block valve unit 24 together with the relief valves 30 arranged in parallel. The relief valve 30 includes a forward relief valve that opens when the pressure on the fuel tank 10 side is sufficiently higher than the pressure on the canister 26 side, and a reverse relief valve that opens in the opposite case. This is a mechanical two-way check valve. The valve opening pressure of the relief valve 30 is set to about 20 kPa in the forward direction and about 15 kPa in the reverse direction, for example. As described above, the vapor passage 20 is provided with the large flow valve 28, the small flow valve 29, and the relief valve 30 in parallel. When any of the valves 28, 29, 30 is opened, the fuel tank 10 and the canister 26 communicates with the vapor passage 20.

  The canister 26 includes a purge hole 32. A purge passage 34 communicates with the purge hole 32. The purge passage 34 is provided with a purge valve (VSV: Vacuum Switching Valve) 36 in the middle thereof, and communicates with an intake passage 38 of the internal combustion engine at an end thereof. An air filter 40, an air flow meter 42, a throttle valve 44, and the like are provided in the intake passage 38 of the internal combustion engine. The purge passage 34 communicates with the intake passage 38 downstream of the throttle valve 44.

  The inside of the canister 26 is filled with activated carbon. The evaporated fuel flowing in through the vapor passage 20 is adsorbed by the activated carbon. The canister 26 also has an air hole 50. An atmospheric passage 54 communicates with the atmospheric hole 50 via a negative pressure pump module 52. The air passage 54 includes an air filter 56 in the middle thereof. The end of the atmospheric passage 54 is open to the atmosphere in the vicinity of the fuel filler port 58 of the fuel tank 10.

  As shown in FIG. 1, the evaporated fuel processing apparatus of this embodiment includes an ECU 60. The ECU 60 has a built-in soak timer for counting the elapsed time while the vehicle is parked. A lid switch 62 and a lid opener 64 are connected to the ECU 60 together with the tank internal pressure sensor 12, the large flow valve 28, the small flow valve 28, the operation detection sensors 91 and 92, or the negative pressure pump module 52 described above. The lid opener 64 is connected to a lid manual opening / closing device 66 by a wire.

  The lid opener 64 is a locking mechanism for a lid (vehicle body lid) 68 that covers the fuel filler opening 58, and when a lid opening signal is supplied from the ECU 60, or a predetermined opening operation is performed on the lid manual opening / closing device 66. When applied, the lid 68 is unlocked. The lid switch 62 connected to the ECU 60 is a switch for sending a command for releasing the lock of the lid 68 to the ECU 60.

  FIG. 1B is an enlarged view for explaining details of the negative pressure pump module 52 shown in FIG. The negative pressure pump module 52 includes a canister-side passage 70 that communicates with the air hole 50 of the canister 26 and an atmosphere-side passage 72 that communicates with the atmosphere. A pump passage 78 including a pump 74 and a check valve 76 communicates with the atmosphere side passage 72.

  The negative pressure pump module 52 also includes a switching valve 80 and a bypass passage 82. The switching valve 80 communicates the canister-side passage 70 with the atmosphere-side passage 72 in a non-energized state (OFF state), and pumps the canister-side passage 70 in a state where an external drive signal is supplied (ON state). The passage 78 is communicated. The bypass passage 82 is a passage through which the canister-side passage 70 and the pump passage 78 are electrically connected, and a 0.5 mm diameter reference orifice 84 is provided in the middle thereof.

  The negative pressure pump module 52 further incorporates a pump module pressure sensor 86. According to the pump module pressure sensor 86, the pressure inside the pump passage 78 can be detected on the check valve 76 side of the check valve 76.

[Description of basic operation]
Next, the basic operation of the evaporated fuel processing apparatus of this embodiment will be described.
(1) During parking The fuel vapor processing apparatus according to this embodiment maintains both the large flow valve 28 and the small flow valve 29 in a closed state in principle while the vehicle is parked. When the large flow valve 28 and the small flow valve 29 are closed, the fuel tank 10 is separated from the canister 26 as long as the relief valve 30 is closed. Therefore, in the evaporated fuel processing apparatus of the present embodiment, the evaporated fuel is newly adsorbed by the canister 26 while the vehicle is parked unless the tank internal pressure Pt exceeds the positive valve opening pressure (20 kPa) of the relief valve 30. There is nothing. Further, as long as the tank internal pressure Pt does not fall below the reverse valve opening pressure (−15 kPa) of the relief valve 30, no air is sucked into the fuel tank 10 during parking of the vehicle.

(2) During refueling In the apparatus of the present embodiment, when the lid switch 62 is operated while the vehicle is stopped, the ECU is activated, and the large flow valve 28 is first opened. At this time, if the tank internal pressure Pt is higher than the atmospheric pressure, the large flow valve 28 opens, and at the same time, the evaporated fuel in the fuel tank 10 flows into the canister 26 and is adsorbed by the activated carbon therein. As a result, the tank internal pressure Pt decreases to near atmospheric pressure.

  When the tank internal pressure Pt decreases to near atmospheric pressure, the ECU 60 issues a command to the lid opener 64 to release the lock of the lid 68. The lid opener 64 receives the command and releases the lock of the lid 68. As a result, in the apparatus according to the present embodiment, the lid 68 can be opened after the tank internal pressure Pt reaches a value near atmospheric pressure.

  When the opening operation of the lid 68 is permitted, the lid 68 is opened, then the tank cap is opened, and then fuel supply is started. Since the tank internal pressure Pt is reduced to near atmospheric pressure before the tank cap is opened, the evaporated fuel is not released from the fuel filler port 58 to the atmosphere in accordance with the opening operation.

  The ECU 60 keeps the large flow valve 28 in an open state until refueling is completed (specifically, until the lid 68 is closed). For this reason, when refueling, the gas in the tank can flow out to the canister 26 through the vapor passage 20, and as a result, good refueling properties are ensured. At this time, the evaporative fuel flowing out is adsorbed by the canister 26 and therefore is not released to the atmosphere.

  By the way, if it takes time until the lid 68 can be opened after the lid switch 62 is operated, the driver feels uncomfortable. The reason why the large flow rate valve 28, not the small flow rate valve 29, is opened in the apparatus of the present embodiment is to shorten the time until the lid 68 can be opened. That is, by opening the large flow valve 28 having a larger diameter, more evaporated fuel is allowed to flow out of the fuel tank 10 and the tank internal pressure Pt is quickly reduced to near atmospheric pressure. From this point of view, the small flow valve 29 may be opened together with the large flow valve 28 instead of opening only the large flow valve 28 as described above. By opening both the large flow rate valve 28 and the small flow rate valve 29, the flow rate of the evaporated fuel from the fuel tank 10 can be increased, and the tank internal pressure Pt can be lowered more quickly. In this case, the opening timing of the large flow valve 28 and the opening timing of the small flow valve 29 may be made different according to the tank internal pressure Pt.

(3) During traveling When the vehicle is traveling, control for purging the evaporated fuel adsorbed by the canister 26 is executed when a predetermined purge condition is satisfied. Specifically, in this control, the purge valve 36 is appropriately duty-driven while the switching valve 80 is turned OFF and the atmospheric hole of the canister 26 is opened to the atmosphere. When the purge valve 36 is driven with a duty, the intake negative pressure of the internal combustion engine 10 is guided to the purge hole 32 of the canister 26. As a result, the evaporated fuel in the canister 26 is discharged into the intake passage 38 of the internal combustion engine together with the air sucked from the air hole 50.

  Further, during the traveling of the vehicle, the open / close state of the large flow valve 28 and the small flow valve 29 is controlled so that the tank internal pressure Pt is maintained near the atmospheric pressure for the purpose of shortening the pressure release time before refueling. However, the valve opening is performed only during the purge of the evaporated fuel, that is, only when the intake negative pressure is introduced into the purge hole 32 of the canister 26. Under the condition where intake negative pressure is introduced to the purge hole 32, the evaporated fuel flowing from the fuel tank 10 into the canister 26 flows out of the purge hole 32 without entering deeply into the canister 26, and is then discharged to the intake passage 38. Is done. Therefore, according to the apparatus of the present embodiment, a large amount of evaporated fuel is not newly adsorbed by the canister 26 while the vehicle is traveling.

  Incidentally, the concentration of the evaporated fuel flowing out of the fuel tank 10 is higher than that of the evaporated fuel released from the canister 26, and the influence on the air-fuel ratio is great. For this reason, if the amount of the evaporated fuel flowing out from the fuel tank 10 is not accurately controlled, the air-fuel ratio fluctuates greatly during the running of the vehicle, the exhaust emission deteriorates, and the drivability deteriorates. End up. Therefore, in the apparatus of the present embodiment, when the tank internal pressure Pt is a high value equal to or higher than a predetermined value, only the small flow valve 29 capable of finely controlling the flow rate is used to perform pressure relief during traveling. Further, when the tank internal pressure Pt becomes lower than a predetermined value, the large flow valve 28 is opened in addition to the small flow valve 29, so that the tank internal pressure Pt is quickly lowered to a value close to the atmospheric pressure. The opening and closing of the large flow rate valve 28 and the small flow rate valve 29 at this time is controlled by duty control by supplying a drive signal from the ECU 60. The ECU 60 appropriately adjusts the energization time of the large flow rate valve 28 and the small flow rate valve 29 to maintain the tank internal pressure Pt of the fuel tank 10 in the vicinity of the atmospheric pressure, so that the air fuel ratio does not fluctuate. The flow rate of the evaporative fuel flowing out from 10 is controlled.

[Explanation of operation at the time of blocking valve failure]
As described above, the apparatus according to the present embodiment has two blocking valves having different diameters, that is, the large flow valve 28 and the small flow valve 29, and roles are assigned to the large flow valve 28 and the small flow valve 29, respectively. It has been. The large flow rate valve 28 and the small flow rate valve 29 are controlled to be opened and closed by the ECU 60 in control modes corresponding to their roles. In order for the evaporative fuel processing device to perform its original function, both the large flow valve 28 and the small flow valve 29 need to operate normally. There is no possibility that one side will fail. Therefore, even if one of the large flow valve 28 and the small flow valve 29 breaks down, it is necessary to take some measures so that the function of the entire evaporated fuel processing apparatus is not impaired. As will be described below, the apparatus of this embodiment switches the control mode of a normal non-failed normal sealing valve from the normal control mode to the control mode for failure, thereby normalizing the function of the failed sealing valve. I'm trying to act on a blockade valve.

  The failure of the block valve includes a closed failure that cannot be opened while the valve and the valve seat are closed, and an open failure that cannot be closed while the valve and the valve seat are open. First, the operation at the time of closing failure will be described. In the apparatus of this embodiment, when the large flow valve 28 is closed, the small flow valve 29 is operated instead in the situation where the large flow valve 28 operates. On the contrary, when the small flow valve 29 is closed, the large flow valve 28 is operated instead in the situation where the small flow valve 29 operates. At this time, the ECU 60 sets the energization time in the duty control of the normal block valve so that the flow rate is obtained if the failed block valve is opened.

  FIG. 2 is a diagram for explaining a method of setting the energization time in duty control. The large flow rate valve 28 and the small flow rate valve 29 are closed when not energized, and are opened when a drive signal is supplied from the ECU 60. The ECU 60 opens and closes the large flow valve 28 and the small flow valve 29 by duty control that repeats supply / stop of the drive signal at a constant cycle. The flow rate of the evaporative fuel flowing out of the fuel tank 10 is determined by the diameter and opening amount of the blocking valve, that is, the energization time per control cycle, and if the energization time is the same, the larger the diameter, The longer the energization time, the larger the flow rate. Therefore, when the small flow valve 29 is operated in place of the large flow valve 28, in order to obtain the same flow rate as the large flow valve 28, as shown in FIG. On time) needs to be set longer than the energization time of the large flow valve 28 (on time in the upper stage in FIG. 2). Conversely, when the large flow valve 28 is operated instead of the small flow valve 29, the energization time of the large flow valve 28 is shorter than the energization time of the small flow valve 29 in order to obtain the same flow rate as the small flow valve 29. Must be set.

The apparatus of this embodiment determines the energization time (final energization time) T2 of each of the large flow valve 28 and the small flow valve 29 by the following equation (1).
T2 = T1 × K1 (1)
In the above equation (1), T1 is the base energization time. The base energization time T1 is stored in the map stored in the ECU 60 in association with the tank internal pressure Pt and the purge flow rate QPG. In this map, the base energization time T1 is set longer as the tank internal pressure Pt is larger than the atmospheric pressure. The base energization time T1 is set to be long when the purge flow rate QPG is large, and the base energization time T1 is set to be short when the purge flow rate QPG is small.

  The map described above is not prepared for each of the large flow valve 28 and the small flow valve 29, but is prepared for each situation where the large flow valve 28 and the small flow valve 29 are operated. When the large flow valve 28 and the small flow valve 29 are both normal, the large flow valve 28 and the small flow valve 29 operate in different situations, so that the large flow valve 28 and the small flow valve 29 are usually based on different maps. Be controlled. However, if either one of the block valves fails, the normal block valve is controlled based on the map on which the failed block valve is based. In the apparatus of the present embodiment, one map is shared by the large flow valve 28 and the small flow valve 29 having different diameters. If the tank internal pressure Pt and the purge flow QPG are the same, the large flow valve 28 and the small flow valve 29 are used. Each base energization time T1 is set to the same value. Then, the difference in flow rate due to the difference in diameter between the large flow valve 28 and the small flow valve 29 is adjusted by the correction coefficient K1 in the equation (1).

  The value of the correction coefficient K1 is selected in relation to the situation in which the block valve operates and the block valve that operates at that time. That is, the correction coefficient K1 is set to 1 when the large flow valve 28 operates normally in the situation where the large flow valve 28 operates. Similarly, the correction coefficient K1 is set to 1 when the small flow valve 29 operates normally in the situation where the small flow valve 29 operates. In this case, the base energization time T1 is not corrected and becomes the final energization time T2, and the large flow valve 28 and the small flow valve 29 are duty-controlled according to the base energization time T1 calculated from the map. In the apparatus of the present embodiment, the duty control of the large flow valve 28 and the small flow valve 29 is always executed in the same control cycle regardless of the failure state of the large flow valve 28 and the small flow valve 29.

  In the situation where the large flow valve 28 is activated, when the small flow valve 29 is activated instead due to a closed failure of the large flow valve 28, the correction coefficient K1 is set to a predetermined value a greater than 1. Thereby, the final energization time T2 is set to a time a times longer than the base energization time T1. Further, in the situation where the small flow valve 29 is operated, when the large flow valve 28 is operated instead due to a closed failure of the small flow valve 29, the correction coefficient K1 is set to a predetermined value b smaller than 1. As a result, the final energization time T2 is set to a time that is b times shorter than the base energization time T1. The predetermined values a and b are set based on the difference in the diameters of the large flow valve 28 and the small flow valve 29 so that the same flow rate can be obtained by the large flow valve 28 and the small flow valve 29.

  On the other hand, the control of the remaining normal block valve when one of the block valves fails to open is different from the control method when one of the block valves described above closes. That is, when one of the shutoff valves is closed, evaporative fuel always leaks from the fuel tank 10, so that when the leaked evaporative fuel flow rate exceeds the target flow rate, the normal shutoff valve The actual flow rate cannot be made the target flow rate no matter how it is controlled. Therefore, when one of the blocking valves fails to open, the opening amount of the normal blocking valve is controlled so as to suppress the outflow of useless evaporated fuel.

  When the large flow valve 28 is in an open failure, the small flow valve 29 is always closed. That is, not only when the large flow rate valve 28 is activated but also when the small flow rate valve 29 is activated, the correction coefficient K1 is set to 0, that is, the energization time T2 is set to 0, and the small flow rate valve 29 is always set. It remains closed. When the small flow valve 29 has an open failure, the large flow valve 28 opens and closes according to the deviation between the flow rate of the evaporated fuel leaking through the small flow valve 29 (hereinafter referred to as the leakage flow rate) and the target flow rate. The state is controlled. Specifically, when the leakage flow rate is larger than the target flow rate, the correction coefficient 1 is set to 0 and the large flow valve 28 is closed. In a situation where the leakage flow rate is smaller than the target flow rate, the correction coefficient K1 is set to a value x corresponding to the difference between the leakage flow rate and the target flow rate, and the large flow valve 28 has the correction coefficient K1 (K1 = x) and the base energization time T1. The duty is controlled according to the final energization time T2 determined from

  The energization time T2 of the above-described large flow valve 28 and small flow valve 29 is calculated by the ECU 60 as a control device of the evaporated fuel processing device according to the routines shown in the flowcharts of FIGS. Specifically, the block valve for opening / closing control is selected by the routine of FIG. 3 and the correction coefficient K1 is calculated. The energization time T2 is calculated using the correction coefficient K1 calculated by the routine of FIG. 3 by the routine of FIG. Calculated. Note that the routine of FIG. 3 and the routine of FIG. 4 are executed independently.

  In the routine shown in FIG. 3, it is first determined which of the large flow valve 28 and the small flow valve 29 is in operation (step 100). As described above, the operation timings of the large flow rate valve 28 and the small flow rate valve 29 are programmed in advance according to the situation such as refueling or traveling, and the ECU 60 is operated based on this program. It is determined which of 29 is in a working situation.

  In a situation where the large flow valve 28 is activated, it is first determined whether or not the large flow valve 28 is closed (step 102). If the large flow valve 28 is not closed, it is further determined whether the small flow valve 29 is open (step 104). In the apparatus of the present embodiment, the failure of the large flow valve 28 and the small flow valve 29 is detected based on signals from the operation detection sensors 91 and 92 attached thereto. For example, if the large flow valve 28 is in a closed failure, the detection signal is not supplied from the operation detection sensor 91 to the ECU 60 regardless of the supply of the drive signal from the ECU 60 to the large flow valve 28. A closed fault is detected. If the small flow valve 29 has an open failure, the detection signal is supplied from the operation detection sensor 92 to the ECU 60 even though the drive signal is not supplied from the ECU 60 to the small flow valve 29. It is detected that 29 has an open failure. An open failure of the large flow valve 28 and a close failure of the small flow valve 29 are similarly detected.

  If the result of the determination in step 102 is that the large flow valve 28 is not closed and the result of the determination in step 104 is that the small flow valve 29 is not open, the determination in step 106 is further performed. Is called. In step 102 and step 120, which will be described later, it is determined whether each of the large flow valve 28 and the small flow valve 29 has a closed failure. One of the causes is that the valve and the valve seat stick to each other. Therefore, in the apparatus of the present embodiment, when one of the blocking valves has not been operated for a long period of time, the blocking valve that has not been operated for a long period of time is operated instead of the other blocking valve in a situation where the other blocking valve is operated. I try to let them. In step 106, it is determined whether the small flow valve 29 has not been used for a long period of time, specifically, whether a predetermined time Ta has elapsed since the previous operation. An elapsed time (continuous valve closing time) from the previous operation of the small flow valve 29 is measured by a timer as a second measuring means provided in the ECU 60.

  As a result of the determination in step 106, when the elapsed time from the previous operation of the small flow valve 29 has not reached the predetermined time Ta, the large flow valve 28 is selected as a block valve for opening / closing control (step 108). Then, the correction coefficient K1 is set to 1 in order to control the large flow valve 28 to open and close as usual (step 110).

  If the result of determination in step 102 is that the large flow valve 28 has a closed failure, the small flow valve 29 is selected as a block valve for opening / closing control instead of the large flow valve 28 (step 112). In addition, as a result of the determination in step 106, even when the predetermined time Ta has elapsed since the previous operation of the small flow valve 29, in order to prevent the small flow valve 29 from sticking, a large flow rate is used as a closing valve for opening / closing control. The small flow valve 29 is selected instead of the valve 28 (step 112). At this time, the correction coefficient K1 is set to a predetermined value a greater than 1 (step 114).

  Although the large flow valve 28 is not closed, if the result of determination in step 104 is that the small flow valve 29 is open, the large flow valve 28 is selected as a block valve for opening and closing control (step 116). ). In this case, the large flow valve 28 is not normally opened / closed, but is opened / closed according to the deviation between the leakage flow rate from the small flow valve 29 and the target flow rate, so the correction coefficient K1 is 0 or the leakage flow rate. And a value x corresponding to the difference between the target flow rate and the target flow rate (step 118).

  On the other hand, in the situation where the small flow valve 29 operates, it is first determined whether or not the small flow valve 29 has a closed failure (step 120). If the small flow valve 29 is not closed, it is further determined whether the large flow valve 28 is open (step 122).

  As a result of the determination in step 120, if the small flow valve 29 is not closed and the large flow valve 28 is not open as a result of the determination in step 122, the large flow valve 28 is further long. It is determined whether it is not used for a period of time, specifically, whether a predetermined time Tb has elapsed since the previous operation (step 124). The elapsed time (continuous valve closing time) from the previous operation of the large flow valve 28 is measured by a timer as a first measuring means provided in the ECU 60. The predetermined time Tb as the determination value used here may be the same value as the predetermined time Ta in step 106, and is set to a different value in consideration of the difference in structure between the large flow valve 28 and the small flow valve 29. May be.

  As a result of the determination in step 124, if the elapsed time from the previous operation of the large flow valve 28 has not reached the predetermined time Tb, the small flow valve 29 is selected as a blocking valve for open / close control (step 126). Then, the correction coefficient K1 is set to 1 to control the small flow valve 29 to open and close as usual (step 128).

  If the result of determination in step 120 is that the small flow valve 29 has a closed failure, the large flow valve 28 is selected as a block valve for opening / closing control instead of the small flow valve 29 (step 134). Further, as a result of the determination in step 124, even when the predetermined time Tb has elapsed since the previous operation of the large flow valve 28, in order to prevent the large flow valve 28 from sticking, a small flow rate is used as a blocking valve for opening / closing control. The large flow valve 28 is selected instead of the valve 29 (step 134). At this time, the correction coefficient K1 is set to a predetermined value b smaller than 1 (step 136).

  Although the small flow valve 29 is not closed, if the result of determination in step 122 is that the large flow valve 28 is open, the small flow valve 29 is always controlled to be fully closed. (Step 130). Therefore, the correction coefficient K1 is set to 0 (step 132).

  When the large flow valve 28 is in an open failure in the situation where the large flow valve 28 is operating, the small flow valve 29 is maintained as usual, that is, in a fully closed state. Similarly, when the small flow valve 29 is in an open failure in the situation where the small flow valve 29 operates, the large flow valve 28 is maintained in a fully closed state. If the small flow valve 29 has a closed failure in the determination in step 104, the process proceeds to the No route and the determination in step 106 is skipped, and the processes in steps 108 and 110 are executed. This is because the determination in step 106 is based on the premise that the small flow valve 29 operates normally. Similarly, if the large flow valve 28 has a closed failure in the determination in step 122, the process proceeds to the No route and the step. The determination of 124 is skipped, and the processing of steps 126 and 128 is executed.

  On the other hand, in the routine of FIG. 4, first, it is determined whether or not a condition for operating either the large flow valve 28 or the small flow valve 29 is satisfied (step 140). The conditions for operating either the large flow valve 28 or the small flow valve 29 are, for example, that the fuel vapor is being purged from the canister 26 and the tank internal pressure Pt is equal to or higher than a predetermined pressure if the vehicle is running. It is that you are.

  As a result of the determination, when the condition for operating either the large flow valve 28 or the small flow valve 29 is satisfied, the correction coefficient K1 set in step 110, 114, 118, 128, 132 or 136 in FIG. It is read (step 142). Subsequently, in step 144, the base energization time T1 corresponding to the current tank internal pressure Pt and the purge flow rate QPG is calculated from the above map. The purge flow rate QPG can be obtained by a known method based on the intake pressure PM and the drive duty ratio of the purge valve 36. The intake pressure PM can be estimated by a known method based on the intake air amount GA and the like. The process of step 144 may be performed before or after the process of step 142, or may be executed simultaneously.

  In the routine shown in FIG. 4, next, the final energization time T2 is calculated according to the above equation (1) based on the correction coefficient K1 read in step 142 and the base energization time T1 calculated in step 144. (Step 146). The ECU 60 performs duty control on the large flow valve 28 or the small flow valve 29 selected in step 108, 112, 116, 126, 130, or 134 in accordance with the final energization time T2 calculated in step 146.

  According to each of the routines described above, even if either one of the large flow valve 28 and the small flow valve 29, which are block valves with different diameters, closes, the remaining normal block valve replaces the block valve that closed. Since it operates, the influence of the closing failure of one of the block valves on the function of the entire fuel vapor processing apparatus is minimized. In particular, when substituting a normal sealing valve, the energization time T2 is set so that the same flow rate as that during normal operation of the failed sealing valve can be obtained. Equal function can be obtained. Further, when either one of the large flow valve 28 and the small flow valve 29 fails to open, the remaining normal block valve is normally closed or the energization time T2 is set to a normal time or less. It is possible to prevent the fuel flow rate from becoming excessive, and to minimize the influence of the open failure of one of the block valves on the function of the entire apparatus. Further, when both the large flow valve 28 and the small flow valve 29 are normal, if one of the block valves has not been operated for a long period of time, the block valve that has not been operated for a long period of time is operated instead of the other block valve. Therefore, sticking of the large flow valve 28 and the small flow valve 29 due to long-term non-use can be prevented.

  By the way, in Embodiment 1 mentioned above, although the operation detection sensors 91 and 92 are provided and the failure of the large flow valve 28 and the small flow valve 29 is detected, the large flow valve 28 and the small flow rate are also detected by other means. A failure of the valve 29 can be detected. For example, when the large flow valve 28 and the small flow valve 29 are normally opened or closed upon receiving a drive signal from the ECU 60, the differential pressure before and after the large flow valve 28 and the small flow valve 29 changes. On the other hand, when the large flow valve 28 and the small flow valve 29 are closed or open, there is no change in the differential pressure. Therefore, by detecting the differential pressure before and after the large flow valve 28 and the small flow valve 29 and comparing the change with the drive signal supply / stop timing from the ECU 60, the large flow valve 28 and the small flow valve 29 are closed. A failure or an open failure can be detected.

  In the first embodiment described above, the “first control means” of the first invention is realized by the execution of the processing of steps 102, 112, and 114 by the ECU 60 or the execution of the processing of steps 122, 130, and 132. Is realized. Further, the “second control means” of the second aspect of the present invention is realized by executing the processes of steps 104, 116, and 118 by the ECU 60, or by executing the processes of steps 120, 134, and 136. Further, the “third control means” of the third invention is realized by the execution of the processing of steps 124, 134, 136 by the ECU 60, and the execution of the processing of steps 106, 112, 114 of the fourth invention by the ECU 60. A “fourth control means” is realized.

Embodiment 2.
Hereinafter, Embodiment 2 of the present invention will be described with reference to FIGS.
The fuel vapor processing apparatus according to the present embodiment causes the ECU 60 to execute the routine of FIG. 6 instead of the routine of FIG. 3 and execute the routine of FIG. 7 instead of the routine of FIG. 4 in the first embodiment. Can be realized.

  In the first embodiment described above, when one of the large flow valve 28 and the small flow valve 29 fails, the energization time in the duty control of the remaining normal block valve is changed. Since the flow rates of the large flow rate valve 28 and the small flow rate valve 29 are determined by the energization time per control cycle in the duty control, not only the energization time is changed as in the first embodiment, but also the energization time remains as it is. The flow rate of the large flow valve 28 and the small flow valve 29 can also be adjusted by changing the flow rate. In the apparatus of this embodiment, the control cycle in the duty control of the normal block valve is set so that the flow rate is obtained when the block valve that has failed is opened, particularly when one block valve is closed.

  FIG. 5 is a diagram for explaining a control cycle setting method in duty control. As described above, the flow rate of the evaporated fuel flowing out from the fuel tank 10 is determined by the diameter of the block valve and the valve opening amount, that is, the energization time per control cycle. If so, the larger the diameter, and the shorter the control period, the larger the flow rate. Therefore, when the small flow valve 29 is operated in place of the large flow valve 28, in order to obtain the same flow rate as the large flow valve 28, as shown in FIG. The cycle of the On / Off waveform) needs to be set shorter than the energization time of the large flow valve 28 (the cycle of the On / Off waveform in the upper stage in FIG. 5). Conversely, when the large flow valve 28 is operated instead of the small flow valve 29, the control cycle of the large flow valve 28 is longer than the control cycle of the small flow valve 29 in order to obtain the same flow rate as the small flow valve 29. Must be set. Since the calculation cycle of the ECU 60 is extremely short compared to the control cycle of the large flow valve 28 and the small flow valve 29, there is no problem in changing the control cycle in this way.

The apparatus of this embodiment determines the control cycle (final control cycle) T4 of the large flow rate valve 28 and the small flow rate valve 29 by the following equation (2).
T4 = T3 × K2 (2)
In the above equation (2), T3 is a base control period, and K2 is a correction coefficient. The base control cycle T3 is a fixed value set in advance, and is set to a constant value regardless of the operating conditions.

  The value of the correction coefficient K2 is selected in relation to the situation in which the block valve operates and the block valve that operates at that time. That is, the correction coefficient K2 is set to 1 when the large flow valve 28 operates normally in the situation where the large flow valve 28 operates. Similarly, the correction coefficient K2 is set to 1 when the small flow valve 29 operates normally in the situation where the small flow valve 29 operates. In this case, the base control cycle T3 is not corrected and becomes the final control cycle T4 as it is, and the large flow valve 28 and the small flow valve 29 are respectively duty controlled according to the base control cycle T3.

  In the situation where the large flow rate valve 28 is activated, when the small flow rate valve 29 is activated instead due to a closed failure of the large flow rate valve 28, the correction coefficient K2 is set to a predetermined value c smaller than 1. Thereby, the final control cycle T4 is set to a time c times shorter than the base control cycle T3. Further, in the situation where the small flow valve 29 operates, when the large flow valve 28 operates instead due to a closed failure of the small flow valve 29, the correction coefficient K2 is set to a predetermined value d greater than 1. Thereby, the final control cycle T4 is set to a time d times longer than the base control cycle T3. The predetermined values a and b are set based on the difference in the diameters of the large flow valve 28 and the small flow valve 29 so that the same flow rate can be obtained by the large flow valve 28 and the small flow valve 29. In the case of such a closed failure, the correction coefficient K1 in the above equation (1) is set to 1, and the base energization time T1 calculated from the map becomes the final energization time T2 as it is.

  On the other hand, if any one of the blocking valves is in an open failure state, the remaining normal blocking valves must be normally closed or opened with a valve opening amount smaller than usual. For this reason, when it is going to adjust a control period like the time of a closed failure, the inconvenience which must take the last control period T4 infinite arises. Therefore, in this embodiment, when any one of the blocking valves has an open failure, as in the first embodiment, it is determined by adjusting the energizing time of a normal blocking valve that has not failed. Yes. In this case, the correction coefficient K2 is set to 1, and the base control cycle T3 is set as it is as the final control cycle T4.

  The energization time T2 and the control cycle T4 of the above-described large flow valve 28 and small flow valve 29 are calculated by the ECU 60 as the control device of the evaporated fuel processing device according to the routines shown in the flowcharts of FIGS. Specifically, the block valve for opening / closing control is selected by the routine of FIG. 6 and the correction coefficients K1 and K2 are calculated. Using the correction coefficients K1 and K2 calculated by the routine of FIG. 6 by the routine of FIG. The energization time T2 and the control cycle T4 are calculated.

  In the routine shown in FIG. 6, the determination processing in steps 200, 202, 204, 206, 220, 222, and 224 is the same as the determination processing in steps 100, 102, 104, 106, 120, 122, and 124 according to the first embodiment. Same content. As a result of the determination in step 202, the large flow valve 28 is not closed, and as a result of the determination in step 204, the small flow valve 29 is not open, and the determination in step 206 is a small flow valve. If the elapsed time from the previous operation 29 has not reached the predetermined time Ta, the large flow valve 28 is selected as a block valve (step 208). The control cycle correction coefficient K2 and the energization time correction coefficient K1 are both set to 1 (step 210).

  As a result of the determination in step 202, if the large flow rate valve 28 has a closed failure, or if the result of determination in step 106 indicates that the predetermined time Ta has elapsed since the previous operation of the small flow rate valve 29, the small flow rate The flow valve 29 is selected as a block valve for opening / closing control (step 212). At this time, the control cycle correction coefficient K2 is set to a predetermined value c greater than 1, and the energization time correction coefficient K1 is set to 1 (step 214).

  If the result of determination in step 204 is that the small flow valve 29 has an open failure, the large flow valve 28 is selected as a closing valve for opening and closing control (step 216), where the energization time correction coefficient K1 is 0, Alternatively, the value x is set according to the difference between the leakage flow rate and the target flow rate, and the control cycle correction coefficient K2 is set to 1 (step 218). If the small flow valve 29 has a closed failure in the determination in step 204, the process proceeds to the No route and the determination in step 206 is skipped, and the processes in steps 208 and 210 are executed.

  On the other hand, in the situation where the small flow valve 29 is operated, the small flow valve 29 is not closed as a result of the determination in step 220, and the large flow valve 28 is not open as a result of the determination in step 222. If the result of determination in step 224 indicates that the elapsed time from the previous operation of the large flow valve 28 has not reached the predetermined time Tb, the small flow valve 29 is selected as a block valve for opening / closing control (step 226). ). The control cycle correction coefficient K2 and the energization time correction coefficient K1 are both set to 1 (step 228).

  As a result of the determination in step 220, if the small flow valve 29 has a closed failure, or if the determination in step 224 indicates that the predetermined time Tb has elapsed since the previous operation of the large flow valve 28, The flow valve 28 is selected as a block valve for opening / closing control (step 234). At this time, the control cycle correction coefficient K1 is set to a predetermined value d greater than 1, and the energization time correction coefficient K1 is set to 1 (step 236).

  If the result of determination in step 222 is that the large flow valve 28 has an open failure, the small flow valve 29 is always controlled to be fully closed (step 230). Here, the energization time correction coefficient K1 is set to 0, and the control period correction coefficient K1 is set to 1 (step 232). If it is determined in step 222 that the large flow valve 28 has a closed failure, the process proceeds to the No route, the determination in step 224 is skipped, and the processes in steps 226 and 228 are executed.

  In the routine of FIG. 7, first, it is determined whether or not a condition for operating either the large flow valve 28 or the small flow valve 29 is satisfied (step 240). As a result of the determination, if a condition for operating either the large flow valve 28 or the small flow valve 29 is satisfied, each correction coefficient K1 set in step 210, 214, 218, 228, 232 or 236 in FIG. , K2 are read (step 242). Subsequently, in step 244, the base energization time T1 corresponding to the current tank internal pressure Pt and the purge flow rate QPG is calculated from the above-mentioned map, and in step 246, a preset base control cycle T3 is read. Note that the processing in step 244 and step 246 may be performed before and after, or may be executed simultaneously.

  Next, in step 248, the final energization time T2 is calculated according to the above equation (1) based on the energization time correction coefficient K1 read in step 242 and the base energization time T1 calculated in step 244. In step 250, based on the control cycle correction coefficient K2 read in step 242 and the base control cycle T3 read in step 246, the final control cycle T4 is calculated according to the above equation (2). Note that the processing of step 248 and step 250 may be performed before and after, or may be executed simultaneously. In accordance with the final energization time T2 calculated in step 248 and the final control cycle T4 calculated in step 250, the ECU 60 selects the large flow valve 28 selected in steps 208, 212, 216, 226, 230, or 234 or the small flow rate valve 28. The flow valve 29 is duty controlled.

  In the above-described second embodiment, the “first control means” of the first invention is executed by the execution of the processing of steps 202, 212, and 214 by the ECU 60 or the execution of the processing of steps 222, 230, and 232. It has been realized. Further, the “second control means” of the second aspect of the invention is realized by the execution of the processing of steps 204, 216, and 218 by the ECU 60 or the execution of the processing of steps 220, 234, and 236. Further, the “third control means” of the third invention is realized by the execution of the processing of steps 224, 234 and 236 by the ECU 60, and the execution of the processing of steps 206, 212 and 214 of the third invention by the ECU 60. A “fourth control means” is realized.

It is a figure for demonstrating the structure of the evaporative fuel processing apparatus of Embodiment 1 of this invention. It is a figure for demonstrating the detailed structure of the negative pressure pump module shown in FIG. 1 (A). It is a figure for demonstrating correction | amendment of the electricity supply time performed in Embodiment 1 of this invention. It is a flowchart of the correction coefficient calculation routine performed in Embodiment 1 of this invention. It is a flowchart of the energization time calculation routine performed in Embodiment 1 of this invention. It is a figure for demonstrating the correction | amendment of the control period performed in Embodiment 2 of this invention. It is a flowchart of the correction coefficient calculation routine performed in Embodiment 2 of the present invention. It is a flowchart of the energization time calculation routine performed in Embodiment 2 of this invention.

Explanation of symbols

10 Fuel tank 12 Tank internal pressure sensor 20 Vapor passage 28 Sealing valve (large flow valve)
29 Sealing valve (small flow valve)
26 Canister 36 Purge valve 38 Intake passage 60 ECU (Electronic Control Unit)
91, 92 Operation detection sensor

Claims (14)

A fuel tank for storing fuel;
A first control valve for controlling a communication state between the fuel tank and the outside;
A second control valve provided in parallel with the first control valve and having a smaller diameter than the first control valve for controlling a communication state between the fuel tank and the outside;
First failure detection means for detecting a failure of the first control valve;
First control means for switching the control mode of the second control valve from a normal control mode to a control mode corresponding to the failure of the first control valve when the first control valve fails;
An evaporative fuel processing apparatus for an internal combustion engine, comprising: A fuel tank for storing fuel;
A first control valve for controlling a communication state between the fuel tank and the outside;
A second control valve provided in parallel with the first control valve and having a smaller diameter than the first control valve for controlling a communication state between the fuel tank and the outside;
Second failure detection means for detecting a failure of the second control valve;
Second control means for switching the control mode of the first control valve from a normal control mode to a control mode corresponding to the failure of the second control valve when the second control valve fails;
An evaporative fuel processing apparatus for an internal combustion engine, comprising: A fuel tank for storing fuel;
A first control valve for controlling a communication state between the fuel tank and the outside;
A second control valve provided in parallel with the first control valve and having a smaller diameter than the first control valve for controlling a communication state between the fuel tank and the outside;
First measuring means for measuring a continuous closing time of the first control valve;
Third control for opening the first control valve instead of the second control valve when the second control valve opens when the continuous closing time of the first control valve exceeds a predetermined time Means,
An evaporative fuel processing apparatus for an internal combustion engine, comprising: A fuel tank for storing fuel;
A first control valve for controlling a communication state between the fuel tank and the outside;
A second control valve provided in parallel with the first control valve and having a smaller diameter than the first control valve for controlling a communication state between the fuel tank and the outside;
Second measuring means for measuring the continuous closing time of the second control valve;
Fourth control for opening the second control valve instead of the first control valve when the first control valve opens when the continuous closing time of the second control valve exceeds a predetermined time Means,
An evaporative fuel processing apparatus for an internal combustion engine, comprising:   The said 1st control means opens the said 2nd control valve in the scene where only the said 1st control valve opens if it is normal when the said 1st control valve is closed failure. The evaporative fuel processing apparatus of the internal combustion engine of 1.   The said 2nd control means opens the said 1st control valve in the scene where only the said 2nd control valve opens if it is normal when the said 2nd control valve is closed failure. 3. A fuel vapor processing apparatus for an internal combustion engine according to 2.   The first control means controls the valve opening amount of the second control valve so that a flow rate obtained by opening the second control valve becomes a flow rate obtained during normal operation of the first control valve. 6. An evaporative fuel processing apparatus for an internal combustion engine according to claim 5, wherein:   The second control means controls the valve opening amount of the first control valve so that the flow rate obtained by opening the first control valve becomes a flow rate obtained during normal operation of the second control valve. The evaporative fuel processing apparatus of the internal combustion engine according to claim 6, characterized in that:   8. The evaporated fuel processing for an internal combustion engine according to claim 7, wherein the first control means opens the second control valve for a time longer than a valve opening time during normal operation of the first control valve. apparatus.   9. The evaporated fuel processing for an internal combustion engine according to claim 8, wherein the second control means opens the first control valve for a shorter time than a valve opening time during normal operation of the second control valve. apparatus.   8. The evaporative fuel processing apparatus for an internal combustion engine according to claim 7, wherein the first control means opens the second control valve at a cycle shorter than a control cycle during normal operation of the first control valve. .   9. The evaporative fuel processing apparatus for an internal combustion engine according to claim 8, wherein the second control means opens the first control valve at a cycle longer than a control cycle during normal operation of the second control valve. .   2. The evaporative fuel processing apparatus for an internal combustion engine according to claim 1, wherein the first control means always closes the second control valve when the first control valve fails to open.   The second control means controls the valve opening amount of the first control valve to a normal value or less in a scene where only the first control valve opens if the second control valve is open when the second control valve is normal. The evaporated fuel processing apparatus for an internal combustion engine according to claim 2.

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