JP5061221B2 - Evaporative fuel processing equipment - Google Patents

Description

  The present invention relates to an evaporated fuel processing apparatus that includes a canister that adsorbs evaporated fuel generated in a fuel tank and processes the evaporated fuel.

  In a conventional evaporative fuel processing apparatus, evaporative fuel generated in a fuel tank is adsorbed to a canister in order to prevent the evaporative fuel generated in a fuel tank from being released into the atmosphere. This reduces the pressure in the fuel tank (see, for example, Patent Document 1).

JP 2001-140705 A

  In a conventional evaporative fuel processing apparatus, a control valve is provided in a vapor passage that communicates a fuel tank and a canister. The control valve is opened before refueling, and evaporative fuel in the fuel tank is adsorbed to the canister via the control valve. The pressure in the fuel tank is reduced. If the pressure can be reduced, it is possible to prevent the evaporated fuel from being released into the atmosphere during refueling.

  In the conventional fuel vapor processing apparatus, the fuel vapor can be adsorbed to the canister by opening the control valve. As such a control valve, a valve having a dead zone, such as a ball valve, is used, and due to a deviation of the position of the valve body when the control valve is closed, the timing shifts from the dead zone to the conduction zone. It may occur.

  Therefore, an object of the present invention is to provide an evaporative fuel processing apparatus that can detect switching between a dead zone region and a conduction region in a control valve.

The present invention is provided in a canister that adsorbs evaporated fuel generated in a fuel tank that stores fuel, and a vapor passage that communicates the fuel tank and the canister, and the opening degree can be increased in the opening direction from the initial position. A control valve that is a ball valve that has a dead zone in which the flow of the evaporated fuel is blocked, and when the degree of opening is larger than that of the dead zone, the ball valve is a conduction region in which the flow of the evaporated fuel is allowed; An evaporative fuel processing apparatus comprising: control means for opening the control valve to flow the evaporated fuel; and opening degree detecting means for detecting the opening degree of the control valve, wherein the control means includes the control valve Switching between the dead zone region and the conduction region in the control valve is determined while operating .

  According to such a configuration, switching between the dead zone region and the conduction region can be detected.

The evaporated fuel processing apparatus further includes tank internal pressure detecting means for detecting an internal pressure of the fuel tank, and the control means operates the control valve and detects the internal pressure of the fuel tank detected by the tank internal pressure detecting means. Based on the above, it may be configured to determine switching between the dead zone region and the conduction region in the control valve.

  The control means increases the opening degree of the control valve in the opening direction from the dead zone, and determines that the control valve has switched from the dead zone to the conduction zone when the internal pressure of the tank starts to decrease. It may be configured to.

  Further, the control means decreases the opening degree of the control valve in the closing direction from the conduction region, and when the internal pressure of the tank becomes constant, the control valve switches from the conduction region to the dead zone region. The structure which determines with having met may be sufficient. In this case, the control means makes the speed of decreasing the opening degree of the control valve in the closing direction from the conduction area smaller than the speed of increasing the opening degree of the control valve in the opening direction from the dead zone area. It may be a configuration.

The evaporative fuel processing device further includes air-fuel ratio detection means for detecting an air-fuel ratio of the air-fuel mixture containing the evaporative fuel supplied to the internal combustion engine, and the control means operates the control valve while operating the control valve. A configuration may be adopted in which switching between the dead zone region and the conduction region in the control valve is determined based on the air-fuel ratio detected by the air-fuel ratio detection unit.

  According to such a configuration, switching between the dead zone region and the conduction region can be detected.

  The control means increases the opening degree of the control valve from the dead zone region in the opening direction, and determines that the control valve is switched from the dead zone region to the conduction region when the air-fuel ratio decreases by a predetermined amount or more. It may be configured to.

  Further, the control means may be configured to store the opening degree at the time of switching detected by the opening degree detection means.

  According to the present invention, switching between the dead zone region and the conduction region in the control valve can be detected.

It is a block diagram of the evaporative fuel processing apparatus (at the time of airtight holding) which concerns on 1st embodiment of this invention. It is a block diagram of the evaporative fuel processing apparatus which concerns on 1st embodiment of this invention, and has shown the state at the time of refueling. It is a block diagram of the evaporative fuel processing apparatus which concerns on 1st embodiment of this invention, and has shown the state at the time of CS MODE driving | running | working (at the time of a purge). It is sectional drawing cut | disconnected by the plane which makes the rotating shaft of the ball | bowl (valve body) of the control valve (ball valve) used for the evaporated fuel processing apparatus which concerns on 1st embodiment of this invention a normal line, (a) Indicates a case where the opening degree of the control valve is zero degrees (fully closed), (b) indicates a case where the opening degree is greater than zero degree and smaller than the maximum opening degree of the dead zone, and (c) indicates a case where the opening degree is the dead band. (D) shows a case where the opening is larger than the maximum opening of the dead zone region and smaller than 90 degrees (fully open), and (e) shows a case where the opening is 90 degrees (fully open). ). It is a graph which shows the relationship of the flow volume of the fuel vapor which flows through a control valve with respect to the opening degree of a control valve. It is a figure for demonstrating the method of learning the maximum opening degree of the dead zone area | region of a control valve, and is a graph which shows the time-dependent change of the tank internal pressure of a fuel tank, and the opening degree of a control valve. It is a figure for demonstrating the method of learning the maximum opening degree of the dead zone area | region of a control valve, and is a graph which shows the time-dependent change of the tank internal pressure of a fuel tank, and the opening degree of a control valve. It is a block diagram of the evaporative fuel processing apparatus which concerns on 2nd embodiment of this invention. It is a figure for demonstrating the method of learning the maximum opening degree of the dead zone area | region of a control valve, and is a graph which shows the time-dependent change of the purge flow rate of evaporated fuel, the air fuel consumption of an internal combustion engine, and the opening degree of a control valve.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

<First embodiment>
FIG. 1 shows a configuration diagram of an evaporative fuel processing apparatus (at the time of hermetically holding) 1A according to the first embodiment of the present invention. The evaporated fuel processing apparatus 1 </ b> A is connected to a vapor passage (pipe) 9, a control valve (ball valve) 11 connected to the vapor passage (pipe) 9, and a vapor passage (pipe) 9 in parallel with the control valve 11. High pressure 2-way valve 10, opening degree detecting means (encoder) 12 for detecting the opening degree of control valve 11, canister 13 to which one end of vapor passage (pipe) 9 is connected, and one end connected to canister 13 The other end is connected to an intake passage (not shown) of an engine (internal combustion engine), a purge passage (pipe) 18, a purge control valve 14 connected to the purge passage (pipe) 18, and the pressure in the canister 13. By switching the pressure sensor 15 to detect, the three-way valve 17, and the direction of ventilation with the three-way valve 17, the fuel tank 3 side with respect to the control valve 11 in the vapor passage (pipe) 9 A pressure sensor 16 for detecting the pressure of the pressure and the canister 13 side, and a control unit 2.

  The other end of the vapor passage (pipe) 9 is connected to the fuel tank 3. A filler pipe 4 and a breather pipe 5 are connected to the fuel tank 3. The other end of the breather pipe 5 is connected to the upper part of the filler pipe 4. The other end of the filler pipe 4 is covered with a filler cap 6.

  The fuel lid 7 further covers the filler cap 6. When the control unit 2 determines that the lid switch 8 is pushed by the driver or the like and then a predetermined condition is satisfied, the control unit 2 opens the fuel lid 7. When the fuel lid 7 is opened, the driver or the like can open the filler cap 6 and supply fuel to the fuel tank 3.

  The fuel tank 3 includes a pump 3 a that sends fuel to an engine (not shown), and a float valve 3 b and a cut valve 3 c provided at an opening to a vapor passage (pipe) 9. The float valve 3 b closes the opening to the vapor passage (pipe) 9 when the so-called full tank is reached, and prevents fuel from entering the vapor passage (pipe) 9. The cut valve 3c does not block the opening to the vapor passage (pipe) 9 even when the so-called full tank is reached. However, for example, the fuel tank 3 tilts and the fuel level rises so that the fuel passes through the vapor passage (pipe) 9. To prevent entering.

  The canister 13 can adsorb evaporated fuel generated in the fuel tank 3 that stores fuel. The canister 13 contains activated carbon or the like, and the evaporated fuel is adsorbed by the activated carbon or the like. Conversely, the canister 13 can purge the evaporated fuel adsorbed in the canister 13 to the engine outside the canister 13 by sucking from the atmosphere and sending the sucked air to the purge passage (pipe) 18. it can.

  The control valve 11 is provided in a vapor passage 9 that allows the fuel tank 3 and the canister 13 to communicate with each other. A ball valve can be used as the control valve 11. Although details will be described later, the ball valve is fully closed at an opening degree of 0 degrees and fully opened at an opening degree of 90 degrees. The opening degree of the control valve (ball valve) 11 can be detected by the opening degree detection means 12, and the detected opening degree is transmitted to the control means 2. Further, the control means 2 can perform open control for opening the control valve 11 and close control for closing it.

  The high-pressure two-way valve 10 has a mechanical valve in which a diaphragm positive pressure valve and a negative pressure valve are combined. The positive pressure valve is configured to open when the pressure on the fuel tank 3 side becomes a predetermined pressure higher than the pressure on the canister 13 side. By this valve opening, the evaporated fuel that has become high pressure in the fuel tank 3 is sent to the canister 13. The negative pressure valve is configured to open when the pressure on the fuel tank 3 side becomes a predetermined pressure lower than the pressure on the canister 13 side. By this opening, the evaporated fuel stored in the canister 13 is returned to the fuel tank 3.

  The purge control valve 14 is provided in a purge passage (pipe) 18. An electromagnetic valve can be used as the purge control valve 14. The purge control valve 14 can be controlled to be opened and closed by the control means 2. The purge passage (pipe) 18 is connected to an engine (internal combustion engine) (not shown), and the control means 2 supplies the purged evaporated fuel to the engine by opening the purge control valve 14.

  A piezoelectric element can be used for the pressure sensors 15 and 16. The pressure sensor 15 is connected to the canister 13 and can detect the pressure in the canister 13. Further, since the pressure in the canister 13 is equal to the pressure in the purge passage 18 and the pressure on the canister 13 side of the control valve 11 in the vapor passage 9, the pressure sensor 15 substantially also has those pressures. It can be detected. The detected pressure is transmitted to the control means 2.

  The pressure sensor 16 is connected to one mouth of the three-way valve 17. The remaining two ports of the three-way valve 17 are connected to the canister 13 side from the control valve 11 of the vapor passage 9 and to the fuel tank 3 side from the control valve 11 of the vapor passage 9. The control means 2 controls the three-way valve 17 to connect the pressure sensor 16 and the control valve 11 of the vapor passage 9 to the canister 13 side, or connect the pressure sensor 16 and the control valve 11 of the vapor passage 9 to the fuel tank 3 side. Can be. If the pressure sensor 16 and the control valve 11 in the vapor passage 9 are connected to the canister 13 side, the pressure sensor 16 detects the pressure on the canister 13 side from the control valve 11 in the vapor passage 9 and further the pressure in the canister 13. be able to. Since the pressure detected at this time should coincide with the pressure detected by the pressure sensor 15, the pressure sensor 15 and 16 can be calibrated and diagnosed. If the three-way valve 17 is controlled and the pressure sensor 16 is connected to the fuel tank 3 side from the control valve 11 in the vapor passage 9, the pressure sensor 16 is connected to the pressure in the fuel tank 3 from the control valve 11 in the vapor passage 9. Can detect the pressure in the fuel tank 3. The pressure sensor 16 transmits the detected pressure to the control means 2.

≪Valve open / close control of evaporated fuel treatment equipment≫
Next, control of the evaporated fuel processing apparatus 1A according to the present embodiment will be described with reference to FIGS. The evaporative fuel processing apparatus 1A according to the present embodiment will be described below as being mounted on a plug-in hybrid vehicle.
FIG. 1 shows the states of “parking” and “CD MODE running” (when sealed), FIG. 2 shows the “fueling” state, and FIG. 3 shows “CS MODE running” (purge). Shows the state. Here, “CD MODE running” means that the engine (internal combustion engine) is running without driving, and “CS MODE running” means that the engine (internal combustion engine) is driven by hybrid (HEV) running. And running.

As shown in FIG. 2, the control means 2 closes the purge control valve 14 and opens the control valve 11 during “fuel supply”, whereby the evaporated fuel (vapor) is adsorbed by the canister 13 and the fuel lid 7 Therefore, the fuel vapor does not leak from the fuel.
Further, as shown in FIG. 3, the control means 2 opens the purge control valve 14 and the control valve 11 during “CS MODE running” (when purging), thereby allowing the evaporated fuel and the canister 13 in the fuel tank 3 to be opened. The adsorbed evaporated fuel flows from the purge passage 18 to the intake passage (not shown) of the engine and is used for combustion in the engine.

  On the other hand, as shown in FIG. 1, the control means 11 controls the control valve 11 so that the evaporated fuel generated in the fuel tank 3 is not adsorbed by the canister 13 during “parking” and “CD MODE running” (when sealed). The valve is closed.

≪Control valve configuration≫
FIG. 4 is a cross-sectional view taken along a plane whose normal is the rotation axis of the ball (valve element) of the control valve (ball valve) 11. FIG. 4A shows a case where the opening degree a of the control valve 11 is zero degrees (fully closed). When the opening degree a is zero degrees (fully closed), the direction of the flow path in the ball (valve body) 11b is inclined by 90 degrees with respect to the direction of the flow path in the valve seat 11a, and the flow in the valve seat 11a The road is closed with a ball (valve element) 11b. A fully closed stopper 11d and a fully opened stopper 11e are attached to the valve seat 11a, and a stem 11c is attached to the ball (valve element) 11b. The stem 11c rotates as the ball (valve element) 11b rotates. When the opening degree a is zero degrees (fully closed), the stem 11c contacts the fully closed stopper 11d so that the ball (valve element) 11b does not rotate counterclockwise as shown in FIG. It has become. The control means 2 performs a closing control for rotating the ball (valve element) 11b and the stem 11c until they do not rotate counterclockwise, and memorizes the degree of opening a in the state of no rotation as zero degrees (zero point). Thus, the zero point correction of the opening degree a can be performed. Further, when the opening degree a is 90 degrees (fully open), the stem 11c contacts the fully open stopper 11e, and does not rotate the ball (valve element) 11b clockwise as shown in FIG. 4 (e). Yes. In FIG. 4, the ball (valve element) 11 b is opened by rotating clockwise, but the present invention is not limited thereto, and may be opened by rotating counterclockwise. What is necessary is just to change the attachment position of the fully closed stopper 11d and the fully open stopper 11e according to the rotation range of the ball | bowl (valve body) 11b and the stem 11c.

  The control valve (ball valve) 11 has a degree of opening where the evaporated fuel does not flow, and the degree of opening is greater than about zero degrees, and the flow rate of the evaporated fuel is opened, in addition to the region where the opening is substantially zero degrees and is fully closed. It has a dead zone B which becomes insensitive to the degree. In the dead zone B, the flow of the evaporated fuel is interrupted even if the opening degree is increased in the opening direction beyond the opening degree zero of the closed position of the control valve 11. In the dead zone B, the evaporated fuel does not flow and the evaporated fuel is not adsorbed by the canister 13. When the opening degree increases from the dead zone B, the flow of the evaporated fuel is allowed.

  As shown in FIG. 4B, when the opening degree a is larger than zero degree and smaller than the maximum Bmax opening degree of the dead zone B, the flow in the valve seat 11a is the same as in the case where the opening degree a is zero degree. The path is blocked by a ball (valve element) 11b, and the evaporated fuel cannot flow through the control valve 11.

  As shown in FIG. 4C, even when the opening degree “a” is equal to the opening degree of the maximum Bmax in the dead zone B, the evaporated fuel cannot flow through the control valve 11.

  As shown in FIG. 4D, when the opening degree a is larger than the maximum opening degree Bmax of the dead zone B and smaller than 90 degrees (fully open), the evaporated fuel can flow through the control valve 11 and pass therethrough. .

  As shown in FIG. 4 (e), when the opening degree a is equal to 90 degrees (fully open), the direction of the flow path in the ball (valve element) 11b matches the direction of the flow path in the valve seat 11a. The control valve 11 can flow the evaporated fuel at the maximum flow rate.

  FIG. 5 shows an example of the relationship between the flow rate of the evaporated fuel flowing through the control valve 11 and the opening a of the control valve 11. The opening degree a is 0 (zero) degree and the flow rate is 0 (zero). Further, the flow rate is 0 (zero) until the opening degree a exceeds 0 (zero) degree and reaches 15 degrees. The range where the flow rate is 0 (zero) and the opening degree a exceeds 0 (zero) degree to 15 degrees is the dead zone B. The opening degree a of 15 degrees is the maximum Bmax of the dead zone B. When the opening degree a exceeds 15 degrees of the maximum Bmax of the dead zone B, the flow rate becomes larger than 0 (zero), and the flow rate increases as the opening degree a increases up to 90 degrees. The control means 2 stores the relationship of the flow rate with respect to the opening degree a as shown in the graph of FIG. 5, and how much flow rate it takes to reduce the pressure in the fuel tank 3 below a predetermined pressure within a predetermined time. Is calculated, and the opening degree a can be determined from the relationship between the calculated flow rate and the stored flow rate with respect to the opening degree a. Note that the flow rate varies depending on the pressure difference between the upstream side and the downstream side of the control valve 11, so this pressure difference may be taken into account when determining the opening degree a.

≪Control valve dead zone maximum opening learning≫
Next, a method for learning the maximum Bmax of the dead zone B of the control valve 11 will be described with reference to FIGS. 6 and 7. The example of FIG. 6 is a case where the maximum Bmax of the dead zone B of the control valve 11 is shifted in a large direction, and the example of FIG. 7 is a shift of the maximum Bmax of the dead zone B of the control valve 11 in a small direction. Is the case. For example, the control unit 2 can perform the learning in FIGS. 6 and 7 at a predetermined learning cycle.

In the example of FIG. 6, the control means 2 has a ball (valve body) of the control valve 11 at a predetermined speed (rotational speed) from a predetermined closed position (initial position, for example, the opening degree a is 0 (zero) degree). ) 11b is rotated to open the control valve 11. Here, at the time of the previous valve opening control, since the tank internal pressure detected by the pressure sensor 16 starts to decrease after the time t _{11 has} elapsed since the valve opening start (t = 0), the control means 2 ₁₁ , it is determined that the control valve 11 has switched from the dead zone region to the conduction region, and the opening degree a ₁₁ at time t ₁₁ is stored in the storage unit in the control means 2 as the maximum Bmax of the dead zone region B.

Thereafter, as in the previous learning, the control means 2 starts the ball of the control valve 11 at a predetermined speed (rotational speed) from a predetermined closed position (initial position, for example, opening degree a is 0 (zero) degree). (Valve element) 11b is rotated to open the control valve 11. Here, at the time of the valve opening control this time, since the tank internal pressure detected by the pressure sensor 16 starts to decrease after the time t _{12 has} elapsed (t ₁₂ > t ₁₁ ) from the start of the valve opening, the control means 2 , the control valve 11 at time _{t 12} is determined to have switched from the dead zone to a conductive region, and stores the degree of opening a ₁₂ at time _{t 12} in the storage unit in the control unit 2 as the maximum Bmax of dead zone B. That is, the control means 2 learns that the maximum Bmax of the dead zone B (the opening degree a of the control valve 11 when switching from the dead zone to the conduction zone) is shifted from the opening degree a ₁₁ to the opening degree a ₁₂ .

On the other hand, in the example of FIG. 7, the control means 2 starts the ball of the control valve 11 at a predetermined speed (rotational speed) from a predetermined closed position (initial position, for example, the opening degree a is 0 (zero) degree). The control valve 11 is opened by rotating the valve body 11b. Here, at time _{t 21} before opening a control valve 11 reaches the opening a ₂₂ is the maximum Bmax of the dead band area B at the time of the previous learning, the maximum Bmax of the opening a of the control valve 11 is dead zone B As a result, the fuel vapor starts to flow and the tank internal pressure starts to decrease. Thereafter, Oite time t _22, the opening a control valve 11 reaches the opening _{a 22} is the maximum Bmax of the previous dead zone B. The control means 11 determines that the tank internal pressure detected by the pressure sensor 16 has started to decrease before the opening degree a of the control valve 11 reaches the maximum Bmax of the dead zone B stored in advance. Then, the ball (valve element) 11b of the control valve 11 is reversely rotated to close the control valve 11. Then, after a time t ₂₃ has elapsed from opening initiation, since the constant tank pressure detected by the pressure sensor 16 after the decrease (amount of change in the tank internal pressure is less than the predetermined value (a state of near-zero)) has become, controller 2 determines that the control valve 11 at time t ₂₃ is switched from the conduction region to the dead zone, stored in a storage unit in the control unit 2 the opening a ₂₃ at time t ₂₃ as the maximum Bmax of dead zone B To do. That is, the control means 2 learns that the maximum Bmax of the dead zone B (the opening a of the control valve 11 when switching from the dead zone to the conduction zone) is shifted from the opening a ₂₂ to the opening a ₂₃ .

In the example of FIG. 7, the control means 2 closes the control valve 11 (reducing the opening in the closing direction from the conduction region from time t ₂₂ to time t ₂₃ ). (from time t = 0 to time t _22, it increases the opening degree in the opening direction from the dead zone B) opened to open and close control of the control valve 11 to be smaller than the rate. By doing so, the detection accuracy of the maximum Bmax of the dead zone B can be increased.

  In the learning method in the example of FIG. 7, the control means 2 is in a state in which the ball (valve element) 11b is displaced and the control valve 11 is in the conductive state in a state where the control valve 2 is in the standby state at the maximum Bmax of the previous dead zone B. It is also applicable when That is, in a state where the opening degree a of the control valve 11 is the maximum Bmax of the previous dead zone B, the ball (valve element) 11b is displaced due to vibration or the like and the control valve 11 becomes a conduction region. The control means 2 determines that the tank internal pressure detected by the pressure sensor 16 starts to decrease, and reverses the ball (valve element) 11b of the control valve 11 to close the control valve 11. When the tank internal pressure detected by the pressure sensor 16 finishes decreasing and becomes constant (the amount of change in the tank internal pressure is less than a predetermined value (substantially zero)), the control means 2 causes the control valve 11 to move from the conduction region to the dead zone. It determines with having switched to the area | region, and memorize | stores the tank internal pressure at that time in the memory | storage part in the control means 2 as the maximum Bmax of the dead zone B. FIG.

  The evaporated fuel processing apparatus 1A according to the first embodiment of the present invention can detect switching between the dead zone region and the conduction region. Specifically, the evaporative fuel treatment device 1A causes a deviation even if a deviation occurs in the timing of passing through the dead zone B and becoming a conduction area due to a deviation in the position of the valve body 11b when the control valve 11 is closed. Since the maximum Bmax of the dead zone B after the operation can be recognized, the vaporized fuel is adsorbed by the canister 13 even when the valve body 11b of the control valve 11 is moved in the dead zone B, and control is performed when the pressure is released. When the valve 11 is desired to be opened slightly, it can be accurately controlled.

<Second Embodiment>
Next, the evaporated fuel processing apparatus according to the second embodiment of the present invention will be described focusing on differences from the evaporated fuel processing apparatus 1A according to the first embodiment. As shown in FIG. 8, the evaporated fuel processing apparatus 1 </ b> B according to the second embodiment includes an engine (internal combustion engine) 19 in which purged evaporated fuel is supplied as an air-fuel mixture via a purge passage 18, and the engine 19. An air-fuel ratio sensor 20 for detecting the air-fuel ratio of the air-fuel mixture containing evaporated fuel (a value obtained by dividing the mass of air in the air-fuel mixture by the mass of evaporated fuel) and outputting the detection result to the control means 2; Prepare. The air-fuel ratio sensor 20 can be realized by an O ₂ sensor provided in an exhaust system (exhaust manifold, catalyst, muffler, etc.) of the engine 19. The air-fuel ratio is detected by the vertical movement of the resistance value of the O ₂ sensor. The

≪Control valve dead zone maximum opening learning≫
Next, a method for learning the maximum Bmax of the dead zone B of the control valve 11 will be described with reference to FIG. In the example of FIG. 9, the control means 2 opens the purge control valve 14 in advance, and supplies an air-fuel mixture containing evaporated fuel to the engine 19. Subsequently, after the amount of evaporated fuel purged toward the engine 19 becomes stable, the control means 2 starts from a predetermined closing degree (for example, the opening degree a is 0 (zero) degree) to a predetermined amount. The control valve 11 is opened by rotating the ball (valve element) 11b of the control valve 11 at a speed (rotational speed). Here, since the air-fuel ratio detected by the air-fuel ratio sensor 20 decreases by a predetermined value k or more after the time t _{31 has} elapsed from the start of valve opening (t = 0), the control means 2 is the time when the air-fuel ratio has started to decrease. At t ₃₁ , it is determined that the control valve 11 has switched from the dead zone region to the conduction region, and the opening degree a ₃₁ at time t ₃₁ is stored in the storage unit in the control means 2 as the maximum B max of the dead zone B. Note that the control means 2 performs feedback control relating to the air-fuel ratio, and the air-fuel ratio once lowered is returned to the original value in order to adjust the amount of fuel vapor and air in the mixture.

  The evaporated fuel processing apparatus 1B according to the second embodiment of the present invention can detect switching between the dead zone region and the conduction region. Specifically, the evaporative fuel processing apparatus 1B causes a deviation even if a deviation occurs in the timing of passing through the dead zone B and becoming the conduction area due to a deviation in the position of the valve body 11b when the control valve 11 is closed. Since the maximum Bmax of the dead zone B after the operation can be recognized, the vaporized fuel is adsorbed by the canister 13 even when the valve body 11b of the control valve 11 is moved in the dead zone B, and control is performed when the pressure is released. When the valve 11 is desired to be opened slightly, it can be accurately controlled.

DESCRIPTION OF SYMBOLS 1A, 1B Evaporative fuel processing apparatus 2 Control means 3 Fuel tank 11 Control valve (ball valve)
12 Opening detection means (encoder)
13 Canister 14 Purge control valve 16 Pressure sensor (Tank internal pressure detection means)
19 Engine (Internal combustion engine)
20 Air-fuel ratio sensor (air-fuel ratio detection means)

Claims (8)

A canister that adsorbs evaporated fuel generated in a fuel tank that stores fuel;
Provided in a vapor passage that communicates the fuel tank and the canister, and has a dead zone region in which the flow of the evaporated fuel is cut off even when the opening degree is increased in the opening direction from the initial position, than the dead zone region When the opening increases , a control valve that is a ball valve that becomes a conduction region in which the flow of the evaporated fuel is allowed;
Control means for opening the control valve to flow the evaporated fuel;
An opening detecting means for detecting the opening of the control valve;
An evaporative fuel processing apparatus comprising:
The evaporated fuel processing apparatus, wherein the control means determines switching between the dead zone region and the conduction region in the control valve while operating the control valve. A tank internal pressure detecting means for detecting the internal pressure of the fuel tank;
The control means determines switching between the dead zone area and the conduction area in the control valve based on the internal pressure of the fuel tank detected by the tank internal pressure detection means while operating the control valve. The evaporative fuel processing apparatus of Claim 1 characterized by the above-mentioned. The control means increases the opening degree of the control valve in the opening direction from the dead zone, and determines that the control valve has switched from the dead zone to the conduction zone when the internal pressure of the tank starts to decrease. The evaporative fuel processing apparatus according to claim 2, wherein: The control means decreases the opening degree of the control valve in the closing direction from the conduction region, and determines that the control valve has switched from the conduction region to the dead zone when the internal pressure of the tank becomes constant. The evaporative fuel processing apparatus according to claim 2, wherein the evaporative fuel processing apparatus is provided. The control means is characterized in that the speed at which the opening degree of the control valve is decreased in the closing direction from the conduction area is smaller than the speed at which the opening degree of the control valve is increased in the opening direction from the dead zone area. The evaporated fuel processing apparatus according to claim 4. An air-fuel ratio detection means for detecting an air-fuel ratio of the air-fuel mixture containing the evaporated fuel supplied to the internal combustion engine;
The control means determines switching between the dead zone area and the conduction area in the control valve based on the air-fuel ratio detected by the air-fuel ratio detection means while operating the control valve. The evaporated fuel processing apparatus according to claim 1. The control means increases the opening degree of the control valve from the dead zone region in the opening direction, and determines that the control valve is switched from the dead zone region to the conduction region when the air-fuel ratio decreases by a predetermined amount or more. The evaporated fuel device according to claim 6. The evaporated fuel processing apparatus according to any one of claims 1 to 7, wherein the control means stores an opening degree at a switching time detected by the opening degree detection means.

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