JPH09184423A - Variable intake air device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a seal member used for a movable intake air pipe from its deformation and/or adhesion. SOLUTION: An ECU 50 makes it drive control on an actuator 27 so as to keep a movable intake air pipe 4 in its half opened state when a specified time passes after the stop of an engine E. Thereby, any deformation and/or adhesion of a fixes seal 9 caused by its contact with the movable intake air pipe 4 are prevented for eliminating any chance of the air intake of a casing 7 to be sucked in the movable intake air pipe 4 on account of failed air tightness between the movable intake air pipe 4 and the second fixed intake air pipe 6 and any blowing up of an engine number of revolution, etc., at the time of starting and/or shifting up of the engine can not take place any more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable intake device, and more particularly to a technique for preventing deformation or adhesion of a movable intake pipe seal member.

[0002]

2. Description of the Related Art In an internal combustion engine used in an automobile or the like, volume efficiency, transient response, etc. greatly change depending on the intake pipe length, surge tank capacity and the like. This is due to the intake pulsation effect and the inertia supercharging effect.Usually, in order to improve the volumetric efficiency, the intake pipe length can be increased in the middle and low rotation range and shortened in the high rotation range. desirable. Therefore, in recent years, the development of a variable intake device that changes the intake pipe length and the like according to the operating state has been advanced. The variable intake system 1 shown in FIG.
Connected to the first fixed intake pipe 3, a movable intake pipe 4 which is rotationally driven in a state of being fitted onto the first fixed intake pipe 3, and a surge tank 5 which communicates with the open end of the movable intake pipe 4. A second fixed intake pipe 6 arranged so as to be connected to the tip,
The casing 7 includes a first fixed intake pipe 3 and a movable intake pipe 4. In the figure, reference numeral 8 is a support arm that supports the movable intake pipe 4, and is rotationally driven by an actuator (not shown). 9 is the second fixed intake pipe 6
Is a fixed seal that is attached to the open end side of the movable intake pipe 4 and abuts against the tip of the movable intake pipe 4, and 10 is a slide that is attached to the base end of the movable intake pipe 4 and abuts against the outer peripheral portion of the first fixed intake pipe 3. It is a seal.

In this variable intake system 1, the movable intake pipe 4 and the second fixed intake pipe 6 are connected as shown by the chain double-dashed line until the engine speed reaches a predetermined speed. Then, the intake pipe length L1 becomes sufficiently long and the surge tank capacity becomes relatively small. On the other hand, when the engine speed exceeds the predetermined speed, the movable intake pipe 4 rotates counterclockwise as shown by the solid line, and in this state, the intake pipe length L2 continuously changes according to the engine speed. The surge tank capacity and surge tank 5 and casing 7
And the total volume.

[0004]

By the way, in the above-mentioned conventional variable intake device, when used for a long period of time, the airtightness between the movable intake pipe and the second fixed intake pipe is increased due to the deformation of the fixed seal. There was a problem that I could not keep it. As shown in FIG. 9 (enlarged view of IX portion in FIG. 8), the rubber fixed seal 9 includes a base portion 12 that is engaged and fixed in an annular groove 11 formed in the casing 7, and a seal lip portion 13. When,
It comprises a bellows portion 14 connecting the base portion 12 and the seal lip portion 13. Then, when the movable intake pipe 4 and the second fixed intake pipe 6 are connected in an operating region of a predetermined rotation speed or less, FIG.
As shown in 0, the seal lip portion 13 contacts the tip flare portion 15 of the movable intake pipe 4, while the bellows portion 14 is pressed and deformed by compression. The seal lip portion 13 adheres to the tip flare portion 15 due to the restoring force of the seal lip portion 13 and itself and the pressure difference between the inside and outside of the movable intake pipe 4, thereby ensuring airtightness.

By the way, since the movable intake pipe 4 and the second fixed intake pipe 6 are connected to each other in an operating region of a predetermined number of revolutions or less, the seal lip portion 13 is used in an operating condition mainly in medium to low speed running in an urban area. Is pressed against the tip flare portion 15 for a long time. Further, during parking, since the movable intake pipe 4 and the second fixed intake pipe 6 are always connected, the seal lip portion 13 is continuously pressed against the tip flare portion 15. Therefore, when the vehicle is often parked for a long time and there are few opportunities for high-speed traveling, the seal lip portion 13 and the bellows portion 14 gradually lose elasticity and are plastically deformed into a shape pressed against the tip flare portion 15. The seal lip portion 13 may adhere to the tip flare portion 15.

In such a state, after the movable intake pipe 4 and the second fixed intake pipe 6 are separated from each other by high-speed traveling, the medium-low speed traveling is started to move the movable intake pipe 4 and the second fixed intake pipe 6 again. When connected, the positional relationship between the seal lip portion 13 and the tip flare portion 15 changes from the initial state due to rattling between the movable intake pipe 4 and the support arm 8. Then, as shown in FIG. 11, the seal lip portion 13 comes into partial contact with the tip flare portion 15 to form a gap 16. When the seal lip portion 13 is adhered to the tip flare portion 15, the seal lip portion 1 is pulled by the tip flare portion 15.
3 may be damaged and the sealing function may be lost at all.

When these phenomena occur, the air in the casing 7 is sucked into the movable intake pipe 4, and the volume of the intake system in the middle and low rotation range becomes excessive. As a result, the engine speed may rise (blowing up) at the time of starting or shifting up, and the intake air amount control by the idle speed control valve may not be performed smoothly, and engine stall may occur.

The present invention has been made in view of the above situation,
An object of the present invention is to provide a variable intake device that prevents deformation and adhesion of the movable intake pipe sealing member.

[0009]

Therefore, according to claim 1 of the present invention, a first fixed intake pipe communicating with an intake port of an internal combustion engine, and a part of an intake passage fitted to the first fixed intake pipe. And a movable intake pipe movably supported with respect to the first fixed intake pipe so that the amount of protrusion from the first fixed intake pipe changes, and the movable intake pipe includes the first fixed intake pipe. Movable intake pipe drive control means for moving relative to the pipe,
The upstream end communicates with the surge tank or atmospheric opening,
A second fixed intake pipe whose downstream end is airtightly connected to an upstream end of the movable intake pipe when the amount of protrusion of the movable intake pipe from the first fixed intake pipe is maximized; In the variable intake system including a casing that houses the movable intake pipe, the movable intake pipe drive control means is configured to separate the movable intake pipe and the second fixed intake pipe when the internal combustion engine is stopped. It is proposed to reduce the amount of protrusion of the movable intake pipe from the first fixed intake pipe.

According to a second aspect, in the variable intake system according to the first aspect, the upstream end of the movable intake pipe and the second
It is proposed that the fixed air-intake pipe is provided with the elastic seal member that is provided in an airtight manner at least on one side of the downstream end portion. Further, in claim 3, claim 1 or 2
In the variable intake device, the movable intake pipe drive control means is configured to connect the movable intake pipe to the second fixed intake pipe at the time of starting the internal combustion engine so as to connect the movable intake pipe to the second fixed intake pipe. We propose a method that increases the amount of protrusion from.

According to a fourth aspect of the present invention, in the variable intake system according to the first to third aspects, the movable intake pipe drive control means waits for a first predetermined time after the internal combustion engine is stopped, and then the movable intake pipe drive control means. It is proposed to reduce the amount of protrusion from the first fixed intake pipe. Further, in claim 5, claims 1 to
In the variable intake system of No. 4, it is proposed that the movable intake pipe drive control means detects the start or stop of the internal combustion engine based on the operation state of the ignition key.

According to a sixth aspect of the present invention, in the variable intake system of the first to fifth aspects, the movable intake pipe drive control means detects a connection state between the movable intake pipe and the first fixed intake pipe. It is proposed to provide a detection means, and to stop the start of the internal combustion engine until it is recognized that the movable intake pipe and the first fixed intake pipe are connected based on the detection result of the connection state detection means.

According to a seventh aspect of the present invention, in the variable intake system according to the sixth aspect, the movable intake pipe drive control means is based on a detection result of the connection state detection means when the internal combustion engine is started, and the second predetermined value. When it is recognized that the movable intake pipe and the first fixed intake pipe are not connected to each other over time, it is proposed to cancel the suspension of the start of the internal combustion engine.

[0014]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. In the description of the embodiments, the same members as those of the conventional device described above are designated by the same reference numerals, and duplicate description will be omitted. FIG. 1 is a schematic configuration diagram of an engine control system to which a variable intake system according to the present invention is applied. Reference numeral E in the figure indicates an in-line four-cylinder gasoline engine for an automobile (hereinafter, simply referred to as an engine). The intake port 20 of the engine E is connected to a variable intake system 1 similar to the one described above via an intake manifold 2 to which a fuel injection valve 21 is attached for each cylinder. Upstream of the air cleaner 22,
An intake pipe 26 including a boost pressure sensor 23, a throttle valve 24, an idle speed control valve 25, etc. is connected. The variable intake system 1 is provided with an actuator 27 including a stepper motor, a worm speed reducer, etc., and rotationally drives the support arm 8 that supports the movable intake pipe 4.

The exhaust port 30 has an exhaust manifold 3
1, an O ₂ sensor 32, a three-way catalyst 33, and an exhaust pipe 34 including a muffler (not shown) are connected. An ignition plug 37 is screwed onto the cylinder head 35 so as to face the combustion chamber 36 of each cylinder, while the crankshaft 3
A crank angle sensor 39 for detecting the engine speed Ne and the like is disposed on the front end side of the engine 8. In FIG. 1, 40 is a throttle sensor that detects the intake manifold pressure Pb, 41 is a water temperature sensor that detects the cooling water temperature TW, 42 is an atmospheric pressure sensor that detects the atmospheric pressure Pa, and 43 is the intake air temperature T.
It is an intake air temperature sensor that detects a. Further, 44 is an ignition coil that outputs a high voltage to the ignition plug 37, 45 is an ignition key switch (hereinafter referred to as a key switch) operated by a driver, and 46 is a position sensor that detects the actual position Preal of the movable intake pipe 4. , 47 are failure warning lights provided in the driver's seat.

In the vehicle compartment, an input / output device (not shown) and a storage device (ROM, RA) containing a large number of control programs are incorporated.
M, BURAM, etc.), central processing unit (CPU), timer counter, etc., ECU (engine control unit)
50 is installed and controls the engine E as a whole. Detection information from the various sensors described above is input to the input side of the ECU 50, and the ECU 50 calculates optimum values such as the fuel injection amount and the ignition timing from the detection information to calculate the fuel injection valve 21 and the ignition coil. 44 etc. are driven. Also, E
The CU 50 determines the position of the movable intake pipe 4 based on the engine speed Ne and the like, drives the actuator 27, and lights the failure warning lamp 47 when the variable intake device 1 fails.

The intake control procedure in this embodiment will be described below with reference to the control flow charts of FIGS. When the driver turns on the key switch 46,
The ECU 50 uses a predetermined control interval (for example, 10
ms), the intake control main routine shown in the flowcharts of FIGS. 2 and 3 is repeatedly executed.

When the intake control main routine is started, E
First, in step S1, the CU 50 reads the driving information from the various sensors described above into the RAM. Next, the ECU 50
Determines in step S3 based on the input signal from the crank angle sensor 39 or the like whether or not the engine E is currently in operation. If this determination is Yes (affirmative), in step S5, the engine It is determined whether the rotation speed Ne is higher than the intake control start rotation speed NeA (5,500 rpm in this embodiment).

If the determination in step S5 is No (negative), such as during low-speed running, the ECU 50
In step S7, the target position Pobj of the movable intake pipe 4 is set to the fully closed position Pshut. Also, if the determination in step S5 is Yes, such as during high-speed traveling, the ECU
In step S9, the target position Pobj of the movable intake pipe 4 is determined from a map (not shown) based on the engine speed Ne, the intake manifold pressure Pb, and the like.
Thereafter, the ECU 50 calculates the deviation ΔP between the target position Pobj and the actual position Preal of the movable intake pipe 4 input from the position sensor 46 in step S11, and drives the actuator 27 in the direction in which the deviation ΔP becomes 0 in step S13. Control.

As a result, in the present embodiment, it is possible to optimize the intake pipe length and surge tank capacity not only in the low and medium speed range but also in the high speed range, and improve the volume efficiency and transient response. I was able to. If the determination in step S3 is No, the ECU 50 first determines in step S15 of FIG. 3 whether or not the key switch 46 is in the ON state. If the determination is No, the driver determines that the engine Is determined to have been stopped, and a stop time control subroutine to be described later is executed in step S17. If the determination in step S15 is Yes, the ECU 50
In step S19, the key switch 46 is set to STAR.
It is determined whether or not it is in the T state. If the determination is Yes, a startup control subroutine to be described later is executed in step S21. Then, the determination in step S19 is N.
If it is o, the ECU 50 determines that the current state is immediately before the start, returns to the start, and repeats the control.

Now, the determination in step S15 of FIG. 3 is No.
If so, the ECU 50 shifts to the control subroutine at the time of stop, reads the operation information from various sensors into the RAM in step S31 of FIG. 4, and then determines whether the stop flag Fstop having an initial value 0 is 1 in step S33. Determine whether or not. Since the determination is No for the first time, the ECU 50 sets the stop flag Fstop to 1 in step S35, and then in step S37.
After starting the wait timer Twait with, return to the start.
Then, since the determination in step S33 becomes Yes after the second time, the ECU 50 determines in step S39 that the standby timer T
It is determined whether or not the wait value has reached a predetermined value T1 (5 seconds in this embodiment), and while this determination is No, the process is not performed and the process returns to the start. This is because, even if the driver once turns off the key switch 46, the key switch 46 may be restarted in a very short time, and in such a case, the variable intake device 1 will not be uselessly operated.

When the value of the wait timer Twait reaches the predetermined value T1 and the determination in step S39 becomes Yes, the ECU 50
Is the target position P of the movable intake pipe 4 in step S41.
Set obj to the half-open position Phalf. After a while, E
The CU 50 calculates the deviation ΔP between the target position Pobj and the actual position Preal in step S43, and in step S43
At 45, the actuator 27 is drive-controlled so that the deviation ΔP becomes zero.

Next, the ECU 50 executes step S4 in FIG.
In step 7, it is determined whether or not the stop drive flag FM1 having an initial value 0 is 1. This determination is No at the first time, so the ECU 5
For 0, the stop drive flag FM1 is set to 1 in step S49, the stop drive timer TM1 is started in step S51, and then the process returns to the start. Then, since the determination in step S47 becomes Yes after the second time, the ECU 50 determines in step S53 whether the deviation ΔP becomes 0, and if the determination is Yes, in step S55 the actuator is determined. The drive control of 27 is stopped, the flags Fstop and FM1 are initialized in step S57, and the control is ended.

As a result, when the vehicle is parked or stopped, the movable intake pipe 4
Is in a half-open state, and the seal lip portion 13 of the fixed seal 9 is caused by the contact with the tip flare portion 15 of the movable intake pipe 4.
Deformation and adhesion are prevented. In addition, the actuator 27
Also, since the engine E is always driven when the engine E is stopped, poor lubrication or the like is less likely to occur in the rotating portion.

If the determination in step S53 is No, the ECU 50 determines in step S59 whether or not the value of the stop drive timer TM1 has reached a predetermined value T2 (1 sec in this embodiment). If the determination is No, the drive of the actuator 27 is continued and the process returns to the start. In the variable intake system 1 of the present embodiment, if there is no malfunction,
The movable intake pipe 4 moves from the fully closed position Pshut to the half open position Phalf in a very short time (about 0.2 sec).

When the actuator 27 or the like has a failure and the determination in step S59 is Yes, the ECU 50 determines that
In step S61, the failure warning light 47 is turned on and RA
Store the fault code in M. Next, the ECU 50 stops the drive control of the actuator 27 in step S63, then initializes the flags Fstop and FM1 in step S65, and ends the control.

On the other hand, the determination in step S19 of FIG. 3 is Yes.
If so, the ECU 50 shifts to the startup control subroutine, reads the operation information from the various sensors into the RAM in step S71 of FIG. 6, and then, in step S73, sets the target position Pobj of the movable intake pipe 4 to the fully closed position. Pshu
Set to t. After that, the ECU 50 executes the step S7.
In step 5, the deviation ΔP between the target position Pobj and the actual position Preal is calculated, and in step S77, the actuator 27 is driven and controlled so that the deviation ΔP becomes zero.

Next, the ECU 50 determines in step S79 whether or not the starting drive flag FM2 having an initial value 0 is 1. Since this determination is No at the first time, the ECU 50
In step S81, the start-time drive flag FM2 is set to 1, the stop-time drive timer TM2 is started in step S83, and then the process returns to the start. Then, since the determination in step S79 becomes Yes after the second time, the ECU 50 determines whether or not the deviation ΔP becomes 0 in step S85 of FIG. 7, and if the determination is Yes, the step The drive control of the actuator 27 is stopped in S87. Next, the ECU 50
Starts the starter (not shown) of the engine E in step S89, and then in step S91 the start drive flag F
Initialize M2 and end the control.

As a result, at the time of starting, the initial explosion of the engine E occurs after the movable intake pipe 4 is fully closed, and the engine speed is prevented from rising. In this embodiment, the movable intake pipe 4 in the half-opened state is instantly closed, so that the degree of adhesion (that is, airtightness) between the tip flare portion 15 of the movable intake pipe 4 and the seal lip portion 13 of the fixed seal 9 is high. Improved.

If the determination in step S85 is No, the ECU 50 determines in step S93 whether or not the value of the start-up drive timer TM2 has reached the predetermined value T3 (1 second in this embodiment). If the determination is No, the drive of the actuator 27 is continued and the process returns to the start. When the actuator 27 or the like has a failure and the determination in step S93 is Yes, the ECU 50 determines in step S95.
In step S97, the failure warning lamp 47 is turned on, the failure code is stored in the RAM, and the drive control of the actuator 27 is stopped in step S97. Next, the ECU 50 executes step S99.
After starting the starter of engine E by step S1,
At 01, the start-up drive flag FM2 is initialized and the control is ended. Here, when the variable intake device 1 fails, the engine E
The reason for starting is to enable self-propelled vehicles such as a repair shop even when it is difficult to eliminate the failure.

As described above, in the above-described embodiment, the movable intake pipe 4 is half-opened when the engine E is stopped, so that the deformation and adhesion of the seal lip portion 13 of the fixed seal 9 which becomes an obstruction factor of intake control are completely completed. It came to be able to prevent it. The description of the specific embodiment has been completed, but the aspect of the present invention is not limited to this embodiment. For example, the above-described embodiment applies the present invention to a variable intake system for an in-line four-cylinder engine, but may be applied to a variable intake system for engines having different numbers of cylinders and cylinder arrangement. Further, in the above-described embodiment, the present invention is applied to the variable intake device in which the movable intake pipe rotates, but may be applied to the variable intake device in which the movable intake pipe linearly moves. Further, the position of the movable intake pipe when the engine is stopped does not necessarily have to be half-opened, and may be moved from fully closed to a small amount or may be fully opened. Further, in the above-described embodiment, the pressure sensor type is used as the intake air amount measuring means, but a Karman vortex type, a hot wire type or the like may be used. Further, in the above-mentioned embodiment, the one that continuously changes the intake pipe length is targeted, but the intake pulsation effect and the inertia supercharging effect are reduced, but the one that gradually changes the intake pipe length and the surge tank capacity is targeted. Good. Further, the specific configuration of the device, the control procedure, and the like can be appropriately changed without departing from the gist of the present invention.

[0032]

According to the first aspect of the present invention, the first fixed intake pipe communicating with the intake port of the internal combustion engine and the first fixed intake pipe are fitted to form a part of the intake passage. A movable intake pipe movably supported with respect to the first fixed intake pipe so that the amount of protrusion from the first fixed intake pipe changes, and the movable intake pipe with respect to the first fixed intake pipe. The movable intake pipe drive control means to be moved and the upstream end communicate with the surge tank or the atmosphere opening port, and the downstream end when the amount of protrusion of the movable intake pipe from the first fixed intake pipe becomes maximum. In a variable intake device having a second fixed intake pipe, a portion of which is airtightly connected to an upstream end of the movable intake pipe, and a casing which houses the movable intake pipe, the movable intake pipe drive control means comprises: When the internal combustion engine is stopped, the movable intake pipe and the In order to separate the 2 stationary intake pipe,
Since the amount of protrusion of the movable intake pipe from the first fixed intake pipe is reduced, deformation or adhesion of the contact portion between the downstream end of the second fixed intake pipe and the upstream end of the movable intake pipe. Can be prevented.

According to a second aspect, in the variable intake system according to the first aspect, at least one of the upstream end of the movable intake pipe and the downstream end of the second fixed intake pipe is
Since the elastic sealing member provided for airtightness is attached, the airtightness between the second fixed intake pipe and the movable intake pipe is improved. Further, according to claim 3, in the variable intake system according to claim 1 or 2, the movable intake pipe drive control means connects the movable intake pipe to the second fixed intake pipe when the internal combustion engine is started. Therefore, the amount of protrusion of the movable intake pipe from the first fixed intake pipe is increased, so that the internal combustion engine is prevented from rising at the time of starting.

According to a fourth aspect of the present invention, in the variable intake system of the first to third aspects, the movable intake pipe drive control means waits for a first predetermined time after the internal combustion engine is stopped, and then moves the movable intake pipe drive control means. Since the projection amount of the intake pipe from the first fixed intake pipe is reduced, the variable intake device does not operate unnecessarily when the internal combustion engine is restarted immediately after it is stopped.

According to a fifth aspect, in the variable intake system according to the first to fourth aspects, the movable intake pipe drive control means detects the start or stop of the internal combustion engine based on the operating state of the ignition key. Because it was a thing
Control becomes relatively easy. Further, according to claim 6, in the variable intake device according to any one of claims 1 to 5, the movable intake pipe drive control means detects a connection state for detecting a connection state between the movable intake pipe and the first fixed intake pipe. The internal combustion engine is stopped until the movable intake pipe and the first fixed intake pipe are connected to each other based on the detection result of the connection state detection means. Blow-up of the internal combustion engine is completely prevented.

According to a seventh aspect of the present invention, in the variable intake system according to the sixth aspect, the movable intake pipe drive control means, based on the detection result of the connection state detection means at the time of starting the internal combustion engine, 2 When it is recognized that the movable intake pipe and the first fixed intake pipe are not connected to each other even after a lapse of a predetermined time, the cancellation of the start of the internal combustion engine is cancelled, and the malfunction of the actuator or the like is resolved. Even if it is difficult to do so, you will be able to run on your own at a maintenance shop.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an engine control system to which a variable intake system according to the present invention is applied.

FIG. 2 is a flowchart showing a procedure of an intake control main routine.

FIG. 3 is a flowchart showing a procedure of an intake control main routine.

FIG. 4 is a flowchart showing a procedure of a control subroutine at a stop time.

FIG. 5 is a flowchart showing a procedure of a stop time control subroutine.

FIG. 6 is a flowchart showing the procedure of a control subroutine at start-up.

FIG. 7 is a flowchart showing a procedure of a control subroutine at startup.

FIG. 8 is a vertical cross-sectional view showing the structure of a variable intake device.

9 is an enlarged view of an IX portion in FIG.

FIG. 10 is a cross-sectional view showing a deformed state of the fixed seal.

FIG. 11 is a cross-sectional view showing a state in which a movable intake pipe is partially contacted with a fixed seal.

[Explanation of symbols]

 1 Variable intake device 2 Intake manifold 3 First fixed intake pipe 4 Movable intake pipe 5 Surge tank 6 Second fixed intake pipe 7 Casing 8 Support arm 9 Fixed seal 20 Intake port 27 Actuator 39 Crank angle sensor 45 Ignition key switch 46 Position sensor 47 Failure warning light 50 ECU

Claims (7)

[Claims] 1. A first fixed intake pipe communicating with an intake port of an internal combustion engine, and a part of an intake passage which is fitted to the first fixed intake pipe and protrudes from the first fixed intake pipe. A movable intake pipe that is movably supported with respect to the first fixed intake pipe so that the amount changes, and a movable intake pipe drive control means that moves the movable intake pipe with respect to the first fixed intake pipe. The upstream end communicates with the surge tank or atmospheric opening,
A second fixed intake pipe whose downstream end is airtightly connected to the upstream end of the movable intake pipe when the amount of protrusion of the movable intake pipe from the first fixed intake pipe is maximized; In the variable intake device including a casing that houses the movable intake pipe, the movable intake pipe drive control means is configured to separate the movable intake pipe and the second fixed intake pipe when the internal combustion engine is stopped. A variable intake device characterized in that the amount of protrusion of the movable intake pipe from the first fixed intake pipe is reduced. 2. The upstream end of the movable intake pipe and the second end
2. The variable intake device according to claim 1, wherein the elastic seal member provided for airtightness is attached to at least one of the downstream end portion of the fixed intake pipe. 3. The movable intake pipe drive control means is configured to connect the movable intake pipe to the second fixed intake pipe at the time of starting the internal combustion engine so as to connect the movable intake pipe to the first fixed intake pipe.
The variable intake device according to claim 1 or 2, wherein an amount of protrusion from the fixed intake pipe is increased. 4. The movable intake pipe drive control means reduces the amount of protrusion of the movable intake pipe from the first fixed intake pipe after a lapse of a first predetermined time after stopping the internal combustion engine. The variable intake device according to any one of claims 1 to 3, which is characterized. 5. The movable intake pipe drive control means detects start or stop of the internal combustion engine based on an operating state of an ignition key.
The variable intake device according to any one of 1. 6. The movable intake pipe drive control means includes a connection state detection means for detecting a connection state between the movable intake pipe and the first fixed intake pipe, and the connection state detection means detects the connection state based on a detection result of the connection state detection means. 6. The variable intake system according to claim 1, wherein the start of the internal combustion engine is stopped until it is recognized that the movable intake pipe and the first fixed intake pipe are connected. . 7. The movable intake pipe drive control means, at the time of starting the internal combustion engine, based on the detection result of the connection state detection means, even if a second predetermined time has elapsed, the movable intake pipe and the first 7. The variable intake system according to claim 6, wherein the stop of the start of the internal combustion engine is released when it is recognized that the fixed intake pipe is not connected.