JPH0481561A - Canister purge controller - Google Patents

Abstract

PURPOSE:To make an air-fuel ratio accurately controllable with feedback control as well as to reduce the extent of variations in the air-fuel ratio by letting purge air continuously flow into an intake passage of an engine. CONSTITUTION:Under the condition that an air-fuel ratio of mixture being fed to an engine 1 by a controller 18 is feedback-controlled, opening of a rotary solenoid valve 10 is controlled on the basis of an input signal out of the controller 8, and a purge of fuel vapor takes place according to the opening. With this constitution, a variation in the air-fuel ratio due to the purged furl vapor is also compensated by the feed back control, and the air-fuel ratio of mixture being fed to the engine 1 is maintained to almost the desired one irrespective of a variation in a purge value of the fuel vapor. Accordingly, with the rotary solenoid valve 10 installed as a valve gear in the point midway in a purge passage 8, opening of a valve body 34 is continuously varied, through which the fuel vapor purge is almost continuously performed with the increase or decrease of the purge valve.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides canister purge control that adsorbs fuel vapor from a fuel tank of an automobile or the like into a canister and sucks it into the combustion chamber of the engine together with the intake air of the engine. It is related to the device.

[Prior art] Conventional canister purge control devices include, for example,
There is one disclosed in Publication No. 0-33316. The fuel vapor purge device of this publication is designed for use in engines equipped with an air-fuel ratio control device that feedback controls the air-fuel ratio of the air-fuel mixture supplied to the engine based on a signal generated by an exhaust gas sensor that detects the concentration of exhaust components in exhaust gas. A fuel vapor purge device for the purpose of the present invention, including a fuel vapor purge passage for guiding stored fuel vapor to an engine intake system, a valve device provided in the middle of the fuel vapor purge passage, and when the control device is in operation. and a control device for opening the valve device.

[Problems to be Solved by the Invention] However, the valve device in the fuel vapor purge device closes the purge passage when not energized and opens the passage when energized, and the on/off of the energization is controlled by the duty ratio. This is a type of solenoid valve in which the valve body opens and closes with a full stroke.

With such a solenoid valve, every time the valve body opens and closes, for example, every time the duty ratio is controlled at 10 to 201-1x, an operating sound (valve body collision sound) is generated and the flow of purge air is interrupted. A sound (so-called popping sound) is generated,
Loud noise.

Furthermore, since purge air containing fuel vapor flows intermittently into the intake passage of the engine, there is a problem in that the air-fuel ratio (A/F) varies depending on whether or not purge is performed. Furthermore, since the amount of fuel vapor contained in the purge air is not constant, this also leads to variations in the air-fuel ratio.

Furthermore, since the purge is performed intermittently, the purge efficiency is impaired, and therefore a large canister with a large fuel vapor adsorption capacity is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a canister that can reduce the noise and air-fuel ratio variations caused by the operation of a valve device, and can also reduce the size of the canister. An object of the present invention is to provide a purge control device.

[Means for Solving the Problems] A canister purge control device of the present invention that solves the above problems is based on a signal generated by an exhaust gas sensor that detects the concentration of exhaust components in exhaust scum, and controls the amount of air-fuel mixture supplied to the engine. A control device that performs feedback control of the air-fuel ratio, a canister that adsorbs fuel vapor from the fuel tank, a purge passage that purges the fuel vapor adsorbed in the canister to the engine intake passage, and a a rotary solenoid valve that continuously increases or decreases the purge amount of fuel vapor flowing through the purge passage by controlling the opening degree of a valve body that controls the opening area of the passage based on an input signal from the control device; a check valve that is provided downstream of the solenoid valve and prevents purging of the purge air due to a backflow of purge air and an intake negative pressure of a predetermined value or more applied to the purge passage; and a bypass passage for purging a certain amount of purge air when the purge passage is closed.

[Operation] According to the above means, the opening degree of the rotary solenoid valve is controlled based on the input signal from the control device under the condition that the air-fuel ratio of the air-fuel mixture supplied to the engine is feedback-controlled by the control device. The purge of fuel vapor is performed according to the degree of opening. As a result, fluctuations in the air-fuel ratio due to purged fuel vapor are compensated for by the feedback control, and regardless of changes in the amount of fuel vapor purged,
The air-fuel ratio of the air-fuel mixture supplied to the engine is maintained approximately at the target air-fuel ratio.

However, according to the rotary solenoid valve installed as a valve device in the middle of the purge passage, by continuously changing the opening degree of the valve body, the purge of fuel vapor is almost continuous with the amount of purge increasing or decreasing. It will be held on.

In addition, a check valve installed downstream of the solenoid valve in the purge passage prevents the purge air from flowing back into the solenoid valve.
Purging of purge air due to intake negative pressure of a predetermined value or more applied to the purge passage is prevented.

Therefore, even if the solenoid valve fails and remains open, the purge amount can be adjusted to the maximum range within which feedback control of the air-fuel ratio is possible by only operating the check valve, and the air-fuel ratio can be kept almost constant. The target air-fuel ratio can be maintained.

Furthermore, when the check valve closes the purge passage due to the intake negative pressure exceeding the predetermined value, a certain amount of purge air is purged through the bypass passage, so that the intake manifold's intake negative pressure is This prevents the canister from overflowing when the temperature is large for a long time.

[Example] [First Example] A first example of the present invention will be described with reference to FIGS. 1-11. FIG. 1 is a schematic configuration diagram showing a canister purge control device of this example.

In the figure, an engine 1 includes an air cleaner (not shown), an intake air amount sensor 2, a fuel injection valve 6, and an intake manifold 4.
A mixture of air and fuel is sucked into the combustion chamber 20 from an intake system including It is designed to be released into the atmosphere after 25 years.

A throttle valve 3 that controls the flow rate of air supplied to the engine 1 is provided in the middle of an intake passage 5 of the intake system. Further, an intake valve 21 and an exhaust valve 22 are attached to the combustion chamber 20 so as to be able to reciprocate. An 02 sensor 19 is attached to the exhaust pipe 24 to detect the concentration of exhaust components in the exhaust gas.

A purge port 7 is provided in the intake manifold 4 downstream and adjacent to the throttle valve 3 .

Note that the purge port 7 is communicated with a purge passage 8, which will be described later.

Further, a canister 9 is connected to the upper part of the fuel tank 15 storing fuel via a steam passage 14 through which fuel vapor passes. The case 9a of the canister 9 is connected to the steam passage 14 on the negative side (upper surface in the drawing) and is provided with a rotary solenoid valve 1o, and has an atmosphere opening 9b formed on the other side (lower surface in the drawing). Inside 12 of case 9a
Activated carbon 11 is accommodated in the opening 9b.
A filter I3 is provided on the side.

One connection port 26 of the rotary solenoid valve 1'0 is connected to the inside 12 of the case 9. The other connection port 27 of the rotary solenoid valve 10 is communicated with the purge port 7 via a purge passage 8 having a check valve 28, which will be described later. This rotary electromagnetic valve 10 will be explained with reference to FIG. 2, which shows a sectional view thereof, and FIG. 3, which shows a sectional view taken along the line 1--2 of FIG.

A flow path 32 having the connection ports 26 and 27 and communicating with the purge passage 8 is formed in the main body 31 . In the body main body 31, the purge passage 8 is opened and closed, that is, the flow passage 3
Valve body 34 consisting of a cylindrical valve that controls the opening area of 2
is provided.

Both ends of the valve shaft 35 with the valve body 34 attached are
It is rotatably supported by the main body 31 via bearings 36 and 37.

One end of the valve shaft 35 (upper end in Figure 2)
protrudes from the side wall of the body main body 31. A housing 40 surrounding a rotary solenoid 38 provided at one end of the valve shaft 35 is attached to its side wall.

A rotor 41 having a magnet is attached to one end of the valve shaft 35 . Further, inside the housing 40, there are pole teeth 49a disposed around the rotor 41.
, 49b, and coils 44a and 44b for exciting the stator 42 are housed. Note that the rotor 41, stator 42, and coils 44a, 44b
The rotary solenoid 38 is configured by the above.

Each coil 44a, 44b is wound on a bobbin 45, and the winding start end of one coil 44a and the winding end of the other coil 44a are connected to each other.
It is connected to the end of the winding b. In other words, as shown in the equivalent circuit of Figure 4 (a), two independent
Book coil 44a.

One winding start end and the other winding end of 44b are connected, and this is connected as a common line to the excitation power source 4G via a terminal. In addition, these coils 4
Each of the remaining terminals 4a and 44b is connected to a switch 47a.
, 47b to the excitation power source 46. Here, the coil 44a is an open-side coil that generates a torque in the valve-opening direction, and the coil 44b is a close-side coil that generates a torque in the valve-closing direction. In addition, the stator 42 has two pole teeth 49a and 49b in total, two each as shown in FIG.
9b and 49b) are arranged apart from each other, and the pole teeth (49a and 49b) of mutually different polarities are arranged close to each other.

The operation of the rotary solenoid valve 10 will be explained. First, the operating principle is as follows. When the power is not energized as shown in FIG. 4(a), a detent torque (restoring force) shown by a solid line in FIG. 5 acts on the rotor 41, and the rotor 41 is balanced and stopped at the position shown. This position is the so-called neutral position of the valve body 34 (
(half-open position), which is an intermediate position between the fully closed position and the fully open position.

Next, when the switch 47a is turned on and the current I is applied as shown in FIG. Occur. As a result, the rotor 41 generates the torque shown by the dotted line in FIG. At this time, the detent torque is also generated, so that as a result, a combined torque of the detent torque and the generated torque is generated.

This resultant torque is called static torque and is shown by the dashed line in FIG. Therefore, the stable point of the rotor 41 is where the static torque is 0, so the rotor 41 is
It is displaced by an angle θ from the position shown in the same figure (b). This angle θ corresponds to the angle amount in the direction in which the valve body 34 is opened,
The generated torque is the valve opening torque. This position is the fully open position of the valve body 34.

Next, when the switch 47a is turned off and the switch 47b is turned on, the fifth rotor 41 is
A static torque that is point symmetrical to the static torque shown in the figure is generated, the displacement angle becomes -θ, and it stably stops at the position of the angle -0. This position is the fully open position of the valve body 34.

Note that when changing from a energized state to a de-energized state, the generated torque disappears and only detent torque exists, so
The rotor 41 returns to the state shown in FIG. 4(a) again, and the valve body 34
is the neutral position.

Under such an operating principle, the open side coil 44a
And the energization (input signal) to the close side coil 44b is as follows.
The control device 18 inputs the signal through duty control as shown in FIG.

The central processing unit (CPU) in the control device 18
Alternatively, a pulse signal for duty control is output to a solenoid drive circuit that outputs the input signal. Here, the drive period T is the reciprocal of the drive frequency Z (1/Z). Then, the drive cycle T and the energization (on) to the open side coil 44a
time t1 and on time t2 to the close side coil 44b
The following formula always holds between .

11+t2=T That is, while the open side coil 44a is energized, the close side coil 44b is not energized, and conversely, while the close side coil 44b is energized, the open side coil 44 is energized.
No electricity is applied to a. Therefore, if tl=12,
Since the torque generated by each coil 44a, 44b on the open side and the close side is the same, the rotor 41 does not rotate. When 11>12, the rotor 41 rotates in the valve opening direction, and conversely, when tl<t2, the rotor 41 rotates in the valve closing direction. Therefore, the opening degree of the valve body 37 can be controlled by changing the time widths of the times tl and t2 of the duty control pulse signals output from the CPU.

By driving the rotor 41 in this way, the valve body 3
4 is rotated, the flow area of the purge passage 8 is increased or decreased, and the amount of purge is controlled.

Further, the time for energizing the two coils 44a and 44b is determined by the control device 18 shown in FIG.
It is controlled by a duty ratio of a fast frequency of 0.00°. Therefore, the valve body 34 does not follow the frequency, but is controlled to a certain opening degree. That is, the control device 18 to which the detection signals of the intake air amount sensor 2, the O2 sensor 19, etc. are inputted is the signal generated by the O2 sensor 19, etc. during low to medium load operation, excluding idle link operation and high load operation. Based on this, a pulse signal (feedback signal) is generated to operate the fuel injector 6 so that the air-fuel ratio of the mixture supplied to the engine becomes the stoichiometric air-fuel ratio, and the signal is output to the solenoid of the injector 6. do. At the same time, the control device 18 outputs a drive current (input signal) to the solenoid coil of the rotary solenoid valve 10.

In addition, in FIG. 1, the purge passage 8 includes a solenoid valve 1.
A check valve 28 located downstream of 0 is provided.

The check valve 28 prevents the backflow of the purge air and the purging of the purge air due to an intake negative pressure of a predetermined value or more applied to the purge passage 8. Housing 5 communicating passage 8
1 has a first seat part 52 projecting like a flange from the center of its inner wall, and a downstream passage part 53 which is divided by the seat part 52 and communicates with each other via a small diameter passage 54 in that part.
55 and a downstream passage section 5 in the seat section 52 downstream thereof.
5, and a second seat portion 56 facing each other with a seat 5 interposed therebetween.

The valve body 58 having a disk-shaped valve portion 58a located in the downstream passage portion 55 has a shaft portion 58b that projects from the valve portion 58a to the upstream passage portion 53 through the small diameter passage 54.

A disk-shaped flange 58c is provided at the tip of the shaft portion 58b. A spring 59 is interposed between the flange 58c and the first seat portion 52.

As shown in FIG. 7, the spring 59 normally biases the valve body 58 in a direction to close its valve portion 58a or first seat portion 52. Further, when the valve body 58 axially moves against the bias (spring 59) of the splinter 59, the valve portion 58a closes the second seat portion 56 after a predetermined stroke movement. A sectional view of this state is shown in FIG.

The movement position of the valve body 58 is determined by the balance between the intake negative pressure applied to the valve body 58 and the spring force of the spring 59, and FIGS. 8 and 9 show cross-sectional views of the state in the middle of movement. There is. In detail, the state of the intake negative pressure applied to the purge passage 8 at -100 mmHg is shown in Fig. 8 and a.
The state of t-200 mmHg is shown in FIG. 9, and the state of at-600 mmHg or more is shown in FIG. 10. Also, the housing 5 of the check valve 28
1. Components such as the valve body 58 and the spring 59 are made of metal or a material with excellent heat resistance.

Therefore, the housing 51 of the check valve 28 has a seventh
As shown in the figure, a bypass passage 29 is formed that communicates the upstream passage section 53 with the downstream side of the second seat section 56. An orifice 29a having a predetermined opening area is provided in the middle of the bypass passage 29.

In the canister purge control device equipped with the rotary solenoid valve 10 described above, the fuel vapor generated in the fuel tank 15 passes through the steam passage 14 to the activated carbon 1 in the canister 9.
1 is adsorbed.

The control device 18 is activated when the ignition key switch is turned on (starting the engine 1). Then, under the condition that the air-fuel ratio of the air-fuel mixture supplied to the engine 1 is feedback-controlled by the control device 18, the coils 44a, 44 of the rotary solenoid valve 10 are controlled by the control device 18.
An input signal is input to b, and the opening degree of the rotary solenoid valve is controlled based on this input signal. Depending on this opening,
The fuel vapor adsorbed on the activated carbon 11 is absorbed into the intake manifold 4.
The air is purged into the intake passage 5 due to the pressure difference between the intake pressure (negative pressure) of the canister 9 and the atmospheric pressure of the canister 9.

As a result, fluctuations in the air-fuel ratio due to purged fuel vapor are compensated for by the feedback control, and the air-fuel ratio of the mixture supplied to the engine is maintained at approximately the target air-fuel ratio regardless of changes in the amount of purged fuel vapor. be done.

According to the rotary solenoid valve 10 provided as a valve device in the middle of the purge passage 8, unlike conventional solenoid valves, the opening degree of the valve body 34 is continuously changed, and at the same time, the purge of fuel vapor is This will be done almost continuously, with the amount increasing and decreasing. Therefore, noise caused by the operating sound of the valve body 34 and the popping sound of the purge air is reduced compared to the conventional one.

In addition, since the purge air flows almost continuously into the intake passage 5 of the engine 1, the air-fuel ratio can be accurately controlled by feedback control, reducing variations in the air-fuel ratio and increasing purge efficiency, resulting in a small capacity and compact size. canister 9 can be adopted.

Further, according to the rotary solenoid valve 10, when de-energized,
When the two coils 44a and 44b are energized for the same time (duty ratio 50%), the valve opening degree is the same, and the valve body 3
4 is in a half-open state, even if icing or gum sticks to the valve body 34 due to a long engine stop, or if the rotary solenoid 38 malfunctions, a purgeable state can be ensured, and the canister 9 It can eliminate the overflow of adsorbed fuel vapor, and can be said to have a so-called fail-safe function.

Also, a check valve 2 provided downstream of the solenoid valve 10 in the purge passage 8
8 prevents a backflow (for example, backfire) of the purge air, and also prevents purging of the purge air due to an intake negative pressure of a predetermined value or more applied to the purge passage 8. Therefore, even if the solenoid valve 10 fails and remains open, the purge amount can be kept within the maximum possible range for feedback control of the air-fuel ratio by only operating the check valve 28, and the air-fuel ratio can be maintained at approximately the target air-fuel ratio. That is, even if the air-fuel ratio deviates from the range where feedback control is possible, the engine will not stall and the intake air amount will not increase so much that overrun will occur, so a fail-safe function can be provided.

Note that FIG. 11 shows a characteristic diagram showing the relationship between the intake negative pressure (mmHg) acting on the valve body 58 of the check valve 28 and the purge amount (1/mln). Since this characteristic has a relationship similar to that between the intake air amount of the engine and the intake negative pressure of the intake manifold, the ratio of the purge amount to the intake air amount can be kept almost constant. For this reason,
Even if the rotary solenoid valve fails, there is little deviation in the air-fuel ratio, and the amount of purge air in the canister 9 can be ensured. Further, the control range of the purge amount by the rotary solenoid valve 10 is performed within the range of the purge amount according to the characteristic diagram.

Further, when the check valve 28 closes the purge passage 8 due to the intake negative pressure exceeding the predetermined value, a certain amount of purge air is purged through the bypass passage 29. Therefore, overflow of the canister 9 is prevented when the negative intake pressure of the intake manifold is high for a long time, such as when the engine is idling or in traffic jams. That is, bypass passage 2
9, when the check valve closes the purge passage 8 due to the intake negative pressure exceeding a predetermined value, the purge air will not be purged at all, so it is predicted that the canister 9 will overflow, but in this example. Bypass passage 2 as in
9 allows a certain amount of purge air to be purged even when the check valve is closed, thereby preventing the canister 9 from overflowing. In addition, what is shown by the two-dot chain line in FIG. 11 is a characteristic diagram of the check valve in the case where the bypass passage 29 is not provided.

In addition, since the components of the check valve 28 are made of metal or a material with excellent heat resistance, there is no heat damage to the check valve 28 due to packfire flowing back into the solenoid valve 10 through the purge passage 8, and the solenoid valve lO can prevent thermal effects.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIG. 12.13. Note that this example is a modification of the rotary solenoid valve 10 in the first example, so only the solenoid valve will be described.

Figure 12 shows a cross-sectional view of the rotary solenoid valve, and Figure 1
In FIG. 13, which shows a cross-sectional view along the xm-xm line in FIG. 2,
A flow passage 62 having the connection ports 26 and 27 and communicating with the purge passage 8 is formed in the main body 61 .

A valve body 64 consisting of a butterfly valve that opens and closes the purge passage 8 is provided within the body 61 of the podium. This valve body 64 is fixed to a valve shaft 65 with a screw 63. The valve shaft 65 is rotatably supported by the main body 61 via a bearing 66.

One end (the upper end in FIG. 12) of the valve shaft 65 projects from the side wall of the main body 61. A housing 70 surrounding a rotary solenoid 68 provided at one end of the valve shaft 65 is attached to its side wall. Note that the housing 70 has a bearing 67 fitted to the end of the valve shaft 65 or a stator 72 to be described later.
It is rotatably supported through.

A rotor 71 having a magnet is attached to one end of the valve shaft 65 via retainers 71a and 71b. Further, inside the housing 70, a rotor 7 is provided.
1, and a coil 74 for exciting the stator 72.
a and 74b are housed in a molded state with resin 73. Note that a rotary solenoid 68 is formed by the rotor 41, stator 42, coils 74a, 74b, etc.
is configured. Also, the connector portion 7 of the housing 70
0a is provided with a terminal 78 that is electrically connected to the coils 74a and 74b.

These coils 74a, 74b are wound around one pobbin 75 at the same time and in the same direction.
The winding start end of one coil 74a and the winding end end of the other coil 74b are connected. Coil 7 in this example
4a and 74b are also connected to the excitation power source similarly to the coil of the first embodiment.

The rotary solenoid valve (designated 101) of this example also has the first
It operates almost in the same way as the example.

The canister purge control device equipped with the rotary solenoid valve 101 described above also provides the same effects as the first embodiment.

[Third Embodiment] A third embodiment of the present invention will be described with reference to FIGS. 14 and 15. Since this example shows a modification of the check valve 28 in the first example, the same portions will be given the same reference numerals and the explanation thereof will be omitted, and only the different configurations will be described in detail.

Fig. 14 showing a cross-sectional view of the check valve and xv- in Fig. 14
In FIG. 15, which shows a sectional view taken along the line XV, in this example, instead of forming the bypass passage 29 in the housing 51,
A groove 58d is formed on the end face of the valve portion 58a of the valve body 58. A bypass passage 291 is formed by this groove 58d and the second seat portion 56. Note that FIG. 14 shows a state in which the valve body 58 closes the second seat portion 56 due to the intake negative pressure of a predetermined value or more applied to the purge passage 8.

The canister purge control device equipped with this check valve 28 (designated with reference numeral 281) also provides the same effects as those of the first embodiment.

[Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to FIGS. 16 and 17. Since this example shows a modification of the check valve 28 in the first example, the same portions will be given the same reference numerals and the explanation thereof will be omitted, and only the different configurations will be described in detail.

Figure 16, which shows a cross-sectional view of the check valve, and X■- in Figure 16
In FIG. 17, which shows a sectional view taken along the line X, in this example, instead of forming the bypass passage 29 in the housing 51,
A through hole is formed in the valve portion 58a of the valve body 58 on both sides thereof, and a bypass passage 292 is formed by the hole. Note that FIG. 16 shows a state in which the valve body 58 closes the second seat portion 56 due to the intake negative pressure of a predetermined value or more applied to the purge passage 8.

The canister purge control device equipped with this check valve 28 (denoted by reference numeral 282) also provides the same effects as those of the first embodiment.

Note that the present invention is not limited to the above-mentioned embodiments, and modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] According to the present invention, a rotary solenoid valve is provided as a valve device provided in the middle of a purge passage, and the rotary solenoid valve is controlled based on an input signal from a control device that performs feedback control of the air-fuel ratio of the air-fuel mixture. Therefore, the noise caused by the operating sound of the valve body and the popping sound of the purge air is reduced compared to the conventional one.

In addition, since purge air flows almost continuously into the engine's intake passage, the air-fuel ratio can be controlled accurately through feedback control, reducing variations in the air-fuel ratio, and increasing purge efficiency, making it possible to reduce capacity. This makes it possible to use a small canister.

In addition, a check valve is provided downstream of the solenoid valve in the purge passage, which prevents the purge air from flowing back into the solenoid valve, and also prevents the purge air from being purged by negative intake pressure above a predetermined value applied to the purge passage. be done. Therefore, even if the solenoid valve fails and remains open, the purge amount can be kept within the maximum possible range for feedback control of the air-fuel ratio simply by operating the check valve. can be maintained at approximately the target air-fuel ratio, thus providing a fail-safe function.

Furthermore, even when the check valve closes the purge passage due to intake negative pressure exceeding the predetermined value, a certain amount of purge air is purged through the bypass passage. Canister overflow can be prevented when the pressure is high for a long time.

[Brief explanation of the drawing]

1 to 11 show a first embodiment of the present invention.
The figure is a schematic configuration diagram of the canister purge control device, Figure 2 is a sectional view of the rotary solenoid valve, Figure 3 is a sectional view taken along the line ■-■ in Figure 2, and Figure 4 (a) is when the rotary solenoid is not energized. Fig. 4 (b) is an explanatory diagram of the operation when energized, Fig. 5 is a characteristic diagram of the torque generated in the rotor of the rotary solenoid, Fig. 6 is an explanatory diagram of duty control of the coil of the rotary solenoid, Figure 7 is a cross-sectional view of the check valve.
8 to 10 are cross-sectional views showing the operating states of the check valve, and FIG. 11 is a characteristic diagram showing the relationship between intake negative pressure and purge amount. Fig. 12 is a cross-sectional view of the rotary solenoid valve, and Fig. 13 is a cross-sectional view of the rotary solenoid valve.
FIG. 2 is a sectional view taken along the xm-xm line in FIG. 2; FIG. 14 is a sectional view of a check valve showing a third embodiment, and FIG. 15 is a sectional view taken along the line xv-xv in FIG. 14. FIG. 16 is a cross-sectional view of a check valve showing a fourth embodiment, and FIG. 17 is a cross-sectional view taken along the line X--X in FIG. 16. ■...Engine 8...Purge passage 9...Canister 0.101...Rotary solenoid valve 8...Control device 9...02 Sensor (exhaust gas sensor) 8.281,2
82...Check valve

Claims (1)

[Scope of Claims] A control device that feedback-controls the air-fuel ratio of a mixture supplied to an engine based on a signal generated by an exhaust gas sensor that detects the concentration of exhaust components in exhaust gas, and a control device that adsorbs fuel vapor from a fuel tank. a purge passage for purging fuel vapor adsorbed in the canister to an intake passage of the engine; and a control device that controls the opening degree of a valve body provided in the middle of the purge passage for controlling the opening area of the passage. a rotary solenoid valve that continuously increases or decreases the purge amount of fuel vapor flowing through the purge passage by controlling based on an input signal from the purge passage; A check valve that prevents purging of purge air due to an applied negative intake pressure of a predetermined value or more, and a bypass that purges a certain amount of purge air when the check valve closes the purge passage due to an intake negative pressure of a predetermined value or more. A canister purge control device with a passageway and.