JPS6338612A - Control device for internal combustion engine having variable length intake pipe - Google Patents

Abstract

PURPOSE:To perform stable combustion, by providing a delay means in any of the control devices so as to control intake synchronously with fuel supply when the device, which changes length of an intake pipe, is actuated interlocking to an opening and closing control valve of fuel. CONSTITUTION:A variable intake pipe 5 is provided in the upstream of a carburetor 1. The variable intake pipe 5 regulates whether or not guide pipes 3, provided in an intake displacement chamber, are connected with a fixed intake pipe 2 so as to adjust the length of the intake pipe. While the carburetor 1 provides in its bottom end the second main jet, bypassing the first main jet, and an opening and closing control valve which opens and closes the second main jet. The opening and closing control valve is controlled such that a negative pressure, acting in a negative pressure acting chamber 33, is switched to the atmospheric pressure and the negative pressure by a selector valve 41. A control unit 50, in accordance with an engine speed, actuates with a delay an intake pipe length variably changing servomotor 51 and the fuel control selector valve 41 in accordance with the operative characteristic of both the servomotor 51 and the selector valve 41 so as to control intake synchronously with fuel.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an internal combustion engine having a variable length intake pipe that performs synchronous operation control of the variable length intake pipe and an on-off control valve disposed inside a carburetor. Related to engine control devices.

(Prior Art) As described in Japanese Unexamined Patent Publication No. 61-49124, the volumetric efficiency of an internal combustion engine has been improved by utilizing the pulsation effect and inertia effect caused by pressure waves generated in the intake pipe during the intake stroke of an internal combustion engine. In order to improve 2. Description of the Related Art Internal combustion engines are known in which a variable-length intake pipe is disposed on the intake side of a carburetor.

Also, inside the carburetor in which this variable length intake pipe is provided on the air intake side, when the variable length intake pipe changes its length, the carburetor In order to optimally control the amount of fuel delivered from the intake pipe, a first main jet is kept open at all times, and a second main jet is opened or closed via an opening/closing control valve that is operated in accordance with changes in the length of the variable length intake pipe. is formed.

On the other hand, the internal combustion engine is equipped with respective drive devices for respectively operating the variable length intake pipe and the opening/closing control valve, and a control device for controlling the operation of these drive devices, respectively, The control device attempted to simultaneously operate the variable length intake pipe and the opening/closing control valve by simultaneously outputting an output corresponding to the engine rotational speed to each of the drive devices.

(Problem to be Solved by the Invention) However, if it is attempted to operate the on-off control valve and the variable length intake pipe with the output simultaneously issued from the control device, the respective driving sources and Due to differences in the power transmission paths from these drive sources, as well as differences in the operating characteristics of the on-off control valve itself and the operating characteristics of the variable-length intake pipe itself, the operation of the on-off control valve and the variable length may differ. It is difficult to synchronize the effects of the operation of the long intake pipe, and therefore, at the relevant time, the mixing ratio of the air from the variable length intake pipe and the fuel delivered from the carburetor having the opening/closing control valve, That is, there is a problem in that the air-fuel ratio tends to deteriorate, and the combustion condition of the internal combustion engine tends to become temporarily unstable.

(Means for Solving the Problems) In order to solve these problems, the first invention of the present invention provides a variable length pipe on the air suction side of the carburetor 1, which can be lengthened or shortened according to the engine rotation speed. In an internal combustion engine that has an intake pipe 5 (2° 3.4) and has an opening/closing control valve 23 inside the carburetor 1 that controls the amount of fuel delivered according to the operation of the variable length intake pipe, a signal generating means 62 that outputs an output according to the magnitude relationship of the engine rotation speed with respect to the engine speed; a first control means 64 that controls the length of the variable length intake pipe 5 according to the output of the signal generating means 62; A second control means 65 controls the opening and closing of the on-off control valve 23 according to the output of the signal generation means 62, and the output from the signal generation means 62 is controlled by the first control means 64 or the second control means 65. It is characterized by being equipped with a delay means 63 that transmits the signal with a predetermined delay time to either one of the variable length intake pipes 5 and the opening/closing control valve 23 according to the engine rotational speed. A control device for an internal combustion engine having a variable length intake pipe, in which the effects of each operation can be performed in substantially synchronization with each other, thereby making the combustion state of the internal combustion engine good and stable at the relevant operation control timing. is intended to provide.

A second aspect of the present invention is that the carburetor 1 has a variable length intake pipe 5 on the air intake side, the length of which can be freely lengthened or shortened depending on the engine rotational speed, and the variable length intake pipe is provided inside the carburetor 1. In an internal combustion engine having an opening/closing control valve 23 that controls the amount of fuel delivered according to operation, a signal generating means 62 that outputs an output according to the magnitude relationship of the engine rotation speed with respect to a predetermined engine rotation speed, and the signal generation means a first control means 64 for controlling the length of the variable length intake pipe 5 according to the output of the signal generating means 62;
a second control means 65 for controlling the opening and closing of the signal generating means 62; a determining means 70 for determining whether the output of the signal generating means 62 is in a gradual increase direction or a gradual decrease direction; a first delay means that delays the output of the signal generation means 62 by a different predetermined time and is provided in parallel between the signal generation means 62 and the first control means 64 or the second control means 65; 71 and a second delay means 72, the variable length intake pipe 5 and the opening/closing control valve 23 are adjusted in accordance with the engine rotational speed and also in accordance with the direction of change of the engine rotational speed. The functions of the respective operations of the internal combustion engine can be performed in substantially synchronization with each other, and thereby the combustion state of the internal combustion engine can be made good and stable at the relevant operation control timing. The purpose is to provide a control device.

(Function) First, the function of the control device for an internal combustion engine having a variable length intake pipe according to the first invention will be explained.

When a reference input signal corresponding to the engine rotational speed is input to the control device, the signal generating means 62.

The output is performed according to the magnitude relationship of the reference input signal, that is, the magnitude relationship of the engine rotational speed. This output is supplied to the first control means 64 for controlling the variable length of the variable length intake pipe S and the second control means 65 for controlling the opening and closing of the opening/closing control valve 23 via respective signal paths. In this case, one of these two signal paths is provided with a delay means 63 that delays the supply of the output by a predetermined time, so that the output is transmitted between the first control means 64 and the second control means. 6
5 with the predetermined delay time between them.

In other words, this predetermined delay time cancels out the time difference between the time required to change the length of the variable length intake pipe 5 and the time required to operate the opening/closing control valve 23 according to the magnitude relationship of the rotational speed of the engine. Therefore, the length change of the variable length intake pipe 5 and the operation of the opening/closing control valve 23 are performed substantially synchronously with each other.

Next, the operation of the control device for an internal combustion engine having a variable length intake pipe according to the second invention will be explained.

When a reference input signal corresponding to the engine rotational speed is input to the control device, the signal generating means 62.

An output is produced according to the magnitude relationship of the reference input, that is, the magnitude relationship of the single engine rotational speed. This output is supplied to the first control means 64 that controls the variable length of the variable length intake pipe 5 and the second control means 65 that controls the opening and closing of the opening/closing control valve 23 via respective signal paths. In this case, since the output of the signal generating means 62 is determined by the determining means 70 as to whether it is in the direction of gradual increase or in the direction of gradual decrease,
On one of the two signal paths, the output of the signal generating means 62 is delayed by a respective predetermined time via a first delay means 71 or a second delay means 72. Therefore, in addition to the magnitude relationship of the engine rotational speed, an output corresponding to the increase/decrease direction relationship is supplied to the variable length intake pipe 5 and the opening/closing control valve 23, respectively.

In other words, each predetermined delay time corresponds to the time difference between the time required to change the length of the variable length intake pipe 5 and the time required to operate the opening/closing control valve 23 in accordance with the magnitude relationship of the engine rotational speed. Even if they differ depending on the rotational speed increase/decrease direction, the time difference is canceled out for each one, so the length change of the variable length intake pipe 5 and the operation of the opening/closing control valve 23 are approximately equal to each other. This will be done synchronously.

(Embodiment of the first invention) An embodiment of the first invention will be described below with reference to the accompanying drawings.

FIG. 3 shows a schematic configuration of a control device provided on the intake side of the internal combustion engine 16, and the carburetor 1 located approximately in the center of FIG. Fixed intake pipe 2 and guide pipe 3 on the right side).

The fixed intake pipe 2 is slidably held by the guide pipe 3.
A variable length intake pipe 5 consisting of a movable intake pipe 4 that can be moved into and out of the right opening end is disposed. Note that the guide tube 3 is
A holding pipe 3a forming a holding part of the movable intake pipe 4 and the holding pipe 3a
An extension tube 3b is connected and fixed to the right end of the holding tube 3a so as to extend to the right.

Further, an intake manifold 6 is connected to the downstream side (left side in the figure) of the carburetor 1, and the carburetor main body 1 is connected to the internal combustion engine 1 via the intake manifold 6.
Connected to the suction side of 6.

Inside the carburetor 1, a venturi section 9 is formed by narrowing the intake passage 7 from the variable length intake pipe 5 with a piston valve 8. A throttle valve 10 is provided on the intake manifold 6 side. The piston valve 8 has a piston spring 11 interposed above it, and is biased downward by the piston spring 11. A diaphragm 12 is attached to the upper circumference of the piston valve 8, and the piston valve 8 can be moved up and down by the diaphragm 12. is supported by

The diaphragm 12 has a suction chamber 14 formed inside thereof that communicates with the venturi portion 9 through a suction hole 13 formed at the lower end of the piston valve 8, while the outside thereof is The intake passage 7
It faces the upstream side of the air hole 15 through an air hole 15.

On the other hand, a needle valve 17 is provided at the lower end of the piston valve 8 so as to vertically cross the venturi portion 9, and the needle valve 17 has a lower portion that can communicate with the venturi portion 9. It is inserted into the main jet holder 18 from above.

As shown in FIG. 4, this main engine 1 holder 18 has a first main jet 19 and a second main jet 20 at the bottom, and the first main jet]-9
via the float chamber 21 which is the fuel reservoir chamber of the carburetor.
It is always in communication with the float chamber 21 through the second main jet 20.

A second fuel passage hole 24 having an on-off control valve 23 with a valve spring 22 interposed is formed below the second main jet 20. It is biased so that its lower portion protrudes below the second fuel passage hole 24 . A third fuel hole 25.25 is formed in the upper part of the opening/closing control valve 23 so that the second main jet 20 and the second fuel hole 24 can communicate with each other.

A diaphragm chamber 30 is located below the second fuel hole 24.
A diaphragm 31 having a generally dish-like overall shape is installed substantially horizontally in the diaphragm chamber 30, and the diaphragm 31 divides the diaphragm chamber 30 into upper and lower parts, and has a fuel passage chamber in its upper part. 32, with a negative pressure action chamber 33 formed at its lower part 6. The diaphragm chamber 30 can communicate with the second fuel passage hole 24, while the diaphragm chamber 30 is bored at the lower end of the float chamber 21. It communicates with the float chamber 21 via a first fuel hole 34,34 provided therein.

Further, the diaphragm 31 is biased upward by a set spring 35 interposed in the negative pressure action chamber 33 below the diaphragm 31, and is biased upwardly by the set spring 35. The protruding opening/closing control valve 2
It can come into contact with the lower end of 3.

On the other hand, a communication pipe 40 is interposed between the negative pressure action chamber 33 and the intake manifold 6, as shown in FIG. One-way valves 42 are arranged sequentially from the negative pressure action chamber 33 side. When the switching valve 41 connects the connecting pipes 40 before and after the switching valve 41, the negative pressure generated on the intake manifold 6 side can be supplied to the negative pressure action chamber 33 side via the one-way valve 42, and , the switching valve 41
When the connecting pipes 40 before and after are shut off, the negative pressure action chamber 33 is made to face the atmosphere.

The switching valve 41 is electromagnetically controlled by a command signal from a control unit 50.

Further, the control unit 50 is configured to perform rotation control of a bush-pull type servo motor 51, and on the other hand, this servo motor 51 is connected to the movable intake pipe 4 via a wire 52 and an arm 53, The movable intake pipe 4 is movable in the left and right directions in the figure according to the rotating direction of the servo motor 51.

On the other hand, FIG. 1 shows the configuration of the control unit 50, and an input terminal 55 of the control unit 50 is connected to the input terminal 55 for detecting the rotational speed of the internal combustion engine from the outside. Spark plug 5G depending on speed
An ignition unit 57 that controls the ignition timing of the engine is connected. Here, the control unit 50 has an input terminal 55
A waveform shaping circuit 58 that adjusts the output of the ignition unit 57 into a predetermined waveform is connected to the ignition unit 57, and an F-V converter is connected to the output side of the waveform shaping circuit 58 to convert the output into a voltage according to the output frequency. (Frequency/voltage conversion circuit)
59 are connected. The output side of the frequency/voltage conversion circuit 59 is connected to one input terminal of a comparator 60, and a predetermined comparison voltage serving as a reference is outputted to the other input terminal of the comparator 60. A reference voltage setting circuit 61 is connected.

The waveform shaping circuit 58, frequency/voltage conversion circuit 59, comparator 60, and base voltage setting circuit 61 constitute a signal generator 62 as a signal generating means.

Further, a first control circuit 64 is connected to the output side of the signal generator 62, that is, the output side of the comparator 60, via a delay circuit 63 serving as a delay means for delaying the supply of the signal by a predetermined time. On the other hand, the second control circuit 65 is directly connected. And the first control circuit 64
The servo motor 51 is connected to the output side of the control unit 50 via the output terminal 66°66,
The operating solenoids 41a of the switching valves 41 are connected to the output side of the second control circuit 65 via the output terminals 67 of the control unit 50, respectively.

Therefore, the first control circuit 64 controls the servo motor 51.
The second control circuit 65 constitutes a first control means for controlling the length of the variable length intake pipe 5 through the switching valve 41, and the second control circuit 65 constitutes a first control means for controlling the opening and closing of the opening/closing control valve 23 through the switching valve 41. 2 constitutes control means.

The operation of this embodiment will be explained below.

First, when the internal combustion engine 16 starts, the ignition unit 57 outputs a predetermined output to the control unit 50 depending on its rotational speed.

When this output signal is input to the signal generator 62, a predetermined voltage (comparison voltage) for comparing the input voltage from the frequency/voltage conversion circuit 59 of the signal generator 62 and the magnitude relationship thereof is applied to the comparator. 60, the comparator 6
0 provides an output according to the magnitude relationship between the input voltage and the comparison voltage.

That is, the signal generator 62 is connected to the ignition unit 5.
A signal corresponding to the engine rotational speed is inputted from 7, and it is determined whether or not the input signal is a signal when the engine rotational speed exceeds a predetermined value, and an output is made in accordance with the determination.

The output of this signal generator 62 is sent to the first control circuit 64 and the second control circuit 65, respectively.
The input to the first control circuit 64 is performed via the delay circuit 63.

The input to the second control circuit 65, which is directly connected to the surface comparator 60, is delayed by a predetermined time.

In this way, the output from the signal generator 62 is input to the first control circuit 64 and the second control circuit 64 with a predetermined time difference, but the output from the first control circuit 64 is input to the output terminal. Servo motor 51 via 66.66
The output of the second control circuit 65 operates the solenoid 41a.

Here, when the rotational speed of the engine gradually increases and exceeds a predetermined rotational speed, the output from the second control circuit 65 becomes
First, the threaded wire 41a is electromagnetically activated to connect the connecting pipes 40 before and after it. Through this communication, the negative pressure generated inside the intake manifold 6 is supplied from inside the intake manifold 6 to the inside of the negative pressure action chamber 33, and accordingly, the pressure inside the negative pressure action chamber 33 gradually decreases. descend to When the pressure within this negative pressure action chamber 33 reaches a predetermined negative pressure value, the negative pressure of the predetermined negative pressure value moves the diaphragm 31 downward so as to resist the biasing force of the set spring 35. By following this downward movement, the opening/closing control valve 23 opens the second fuel hole 2.
4 is closed.

As a result, by this time, the fuel flows from the float chamber 21 into the main jet holder 18 through the first fuel hole 34, the second fuel hole 24, the third fuel hole 25, and the second main jet 20. Since the fuel that was being sent out is blocked from the second fuel hole 24 that forms part of its delivery route, the fuel that is being sent out from the main jet holder 18 to the venturi section 9 is transferred to the main jet holder 18 and the float. Only the first main jet 19 which is in continuous communication with the chamber 21 is provided.

In this way, in order to close the opening/closing control valve 23 by the operation of the treid 41a, as described above, the effect of negative pressure in the intake manifold is utilized. A predetermined time is required from the time to the end of the operation of the on-off control valve 23.

On the other hand, the output from the first control circuit 64 that is delayed by a predetermined time after the output from the second control circuit 65 is transmitted to the servo motor 5.
1 in a predetermined direction, and furthermore, the wire 52 and the arm 5 are mechanically directly connected to the servo motor 51.
3, the movable intake pipe 4 is moved to the right in the figure.

Due to this rightward movement, the movable intake pipe 4 quickly moves away from the fixed intake pipe 2, thereby substantially shortening the variable length intake pipe 5. In this case, the servo motor 5]
- and the movable intake pipe 4 are mechanically directly connected, so it takes almost no time from the start of the operation of the servo motor 51 until the variable length intake pipe 5 finishes changing its length. Therefore, the delay time between the output of the first control circuit 64 and the output of the second control circuit 65 is determined by the time required for the variable length intake pipe 5 to change its length from these outputs, and the time required for the variable length intake pipe 5 to change its length from these outputs, and the time required for the variable length intake pipe 5 to change its length from these outputs. The length change of the variable length intake pipe 5 and the opening/closing control valve 2 are offset by the time difference between the time required for the variable length intake pipe 5 and the opening/closing control valve 2 to operate.
The operations No. 3 and 3 are performed substantially synchronously with each other.

Next, when the engine rotational speed is decelerated and becomes lower than the predetermined rotational speed, the toroid 41a controls the first control circuit 64.
With the output of The pressure gradually rises to the atmospheric pressure side. As the pressure increases, the diaphragm 31 moves upward due to the bias of the set spring 35, causing the opening/closing control valve 23 to perform an opening operation.

Even in this case, since the action of the atmospheric pressure is carried out via the communication pipe 40, a predetermined time is required from the start of the operation of the toroid 41a to the end of the operation of the opening/closing control valve 23.

On the other hand, as described above, the servo motor 51 is operated with a predetermined time delay after the operation of the treid 41a, but the movable intake pipe 4 is rotated as shown in the figure by the rotational movement of the servo motor 51 in a predetermined direction. The time required to move to the left and connect to the fixed intake pipe 2 is determined by the time required to move to the left and connect to the fixed intake pipe 2. This is much shorter than the time required from the operation of the nodule 41a to the opening operation of the on-off control valve 23.

Therefore, at this time, as described above, the length change of the variable length intake pipe 5 and the operation of the opening/closing control valve 23 are performed substantially synchronously with each other.

(Embodiment of the second invention) Next, an embodiment of the second invention will be described based on the accompanying drawings.

FIG. 2 shows a control unit 5 which is the main part of the present invention.
Similarly to the embodiment shown in FIG. 1, a signal generator 62 is connected to the input terminal 55 of the control unit 50'.
A discrimination circuit 70 is connected to the output side of the signal generator 62, and this discrimination circuit 70 discriminates whether the sign of the output of the signal generator 62 changes, that is, whether the engine rotation is gradually increasing or decreasing. There is. This discrimination circuit 70 includes a first delay circuit 71 connected in parallel to the output side of the signal generator 62.
and a second delay circuit 72, and both delay circuits 71 and 72 respectively control the drive of the servo motor 51 in accordance with the output of the discrimination circuit 70. Note that a second control circuit 65 that controls the operation of the solenoid 41a is directly connected to the output side of the signal generator 62.

Note that other configurations of the control unit 50' are as follows:
Since the structure is the same as that of the embodiment of the first invention described above, a redundant explanation will be omitted and the same reference numerals will be used for the same constituent parts.

Hereinafter, the operation of an embodiment of the second invention will be explained.

When the rotational speed of the engine gradually increases and exceeds a predetermined rotational speed,
The output of the signal generator 62 is sent to the first control circuit 64 and the second control circuit 65, respectively.
The discrimination circuit 70 supplies the output determined to be at the time of gradual increase in engine rotational speed to the first delay circuit 71, and the output of the first delay circuit 71 is transmitted to the first control circuit 64 after a predetermined delay time. The first control circuit 64 rotates the servo motor 51 in a predetermined direction after the predetermined delay time.

On the other hand, since the second control circuit 65 is directly connected to the signal generator 62, the operation of the solenoid 41a is performed substantially simultaneously with the output of the signal generator 62; The time difference between the start of the operation of the servo motor 41a and the start of the rotation of the servo motor 51 is determined by the time required until the closing operation of the on-off control valve 23 is completed due to these operations or rotations, and the time difference between the start of the operation of the servo motor 41a and the start of the rotation of the servo motor 51. The operation of the opening/closing control valve 23 and the variable length intake pipe 4 at this time is substantially synchronized by offsetting the difference in time required to shorten the variable length intake pipe 5 due to the direction movement. It will be carried out.

Next, when the rotational speed of the engine gradually decreases below the predetermined rotational speed, the output from the signal generator 62 changes in accordance with the change in rotational speed. At this time, the discrimination circuit 70 supplies the second delay circuit 72 with an output that has been determined to be the output from the signal generator 62 when the engine rotational speed is gradually decreasing.

Therefore, similarly to the case where the engine rotational speed is gradually increased, the start of rotation of the servo motor 51 is delayed by a predetermined time from the start of the operation of the solenoid 41a, but the delay time is longer than the delay time when the engine speed is gradually increased. It is a predetermined short length.

This is because the movable intake pipe 4 connects to the fixed intake pipe 2 from the start of rotation of the servo motor 51, and the variable length intake pipe S
The time required for the solenoid 4 to reach the extended state is
From the start of operation of valve 1a, the opening/closing control valve 2 is opened by the action of atmospheric pressure.
This is because the time required for No. 3 to reach the open state is a predetermined shorter time, and the time difference is also predetermined smaller than the case of gradual increase described above.

Therefore, even during the period when the engine rotational speed gradually decreases, the length change of the variable length intake pipe 5 and the operation of the opening/closing control valve 23 are performed substantially synchronously with each other.

In addition, both the embodiments of the first invention and the second invention,
The operation of the variable length intake pipe has been explained using a servo motor, and the operation of the opening/closing control valve of the carburetor has been explained using a combination of a solenoid and a diaphragm, but this is just one example, and various methods can be used as long as the above-mentioned function can be achieved. How to set the delay time of each delay means or which side of the control means to delay is arbitrary depending on the device.

(Effects of the Invention) As described in detail above, according to the first aspect of the present invention, the carburetor has a variable length intake pipe on the air intake side that can be lengthened or shortened depending on the engine rotation speed, and the carburetor In an internal combustion engine having an opening/closing control valve for controlling a fuel delivery amount in accordance with the operation of the variable-length intake pipe, the signal generating means generates an output according to a magnitude relationship of the engine rotation speed with respect to a predetermined engine rotation speed. a first control means for controlling the length of the variable length intake pipe in accordance with the output of the signal generating means; and a second control means for controlling the opening and closing of the opening/closing control valve in accordance with the output of the signal generating means. and a delay means for transmitting the output from the signal generator stage to either the first control means or the second control means with a predetermined delay time. , the length change of the variable length intake pipe according to the engine rotational speed and the opening and closing of the opening/closing control valve can be performed in substantially synchronization with each other, and the combustion state of the internal combustion engine at the relevant operation control period can be maintained in a good and stable manner. can be made into something.

Further, according to the second aspect of the present invention, the carburetor has a variable length intake pipe on the air intake side that can be lengthened or shortened depending on the engine rotational speed, and the variable length intake pipe is provided inside the carburetor. In an internal combustion engine having an opening/closing control valve that controls a fuel delivery amount according to a first control means for controlling the variable length of the variable length intake pipe according to the output of the signal generating means; a second control means for controlling the opening and closing of the opening/closing control valve according to the output of the signal generating means; and an output of the signal generating means gradually increasing. a determining means for outputting an output that determines whether the direction is in the direction or the direction in which the signal is gradually decreasing; Since the present invention is characterized by comprising a first delay means and a second delay means provided in parallel with the first control means or the second control means, in addition to the effect of the first invention, the engine rotation The length change of the variable length intake pipe and the opening/closing of the opening/closing control valve can be performed in substantially synchronization with each other in accordance with the direction of increase/decrease in speed, and the combustion state of the internal combustion engine at the relevant operation control timing can be well stabilized. It can be done as a result.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a control unit that is a main part of an embodiment according to the first invention. FIG. 2 is a block diagram showing the configuration of a control unit that is a main part of an embodiment according to the second invention, and FIG. 3 is a variable intake pipe in which the control unit of FIG. 1 or 2 is installed. FIG. 4 is a longitudinal sectional view showing the structure of the lower part of the carburetor. DESCRIPTION OF SYMBOLS 1... Carburetor, 5... Variable length intake pipe, 23... Opening/closing control valve, 62... Signal generator (signal generating means), 63
...Delay circuit (delay means), 64...First control circuit (first control means), 65...Second control circuit (second control means), 70...Discrimination circuit (discrimination means) , 71...
First delay circuit (first delay means), 72... second delay circuit (second delay means).

Claims (1)

[Scope of Claims] 1. The carburetor has a variable length intake pipe on the air intake side, the length of which can be lengthened or shortened depending on the engine rotational speed, and the carburetor has a variable length intake pipe whose length can be freely lengthened or shortened depending on the engine rotation speed, and inside the carburetor, fuel is supplied according to the operation of the variable length intake pipe. In an internal combustion engine having an opening/closing control valve for controlling a delivery amount, the signal generating means outputs an output according to a magnitude relationship of the engine rotational speed with respect to a predetermined engine rotational speed, and the variable length according to the output of the signal generation means. a first control means for controlling the length of the intake pipe;
a second control means for controlling the opening and closing of the opening/closing control valve according to the output of the signal generation means; 1. A control device for an internal combustion engine having a variable length intake pipe, comprising a delay means for transmitting the signal with a delay time. 2. The carburetor has a variable-length intake pipe on the air intake side that can be lengthened or shortened depending on the engine rotational speed, and an opening/closing device inside the carburetor that controls the amount of fuel delivered according to the operation of the variable-length intake pipe. In an internal combustion engine having a control valve, a signal generating means for outputting an output according to a magnitude relationship of the engine rotation speed with respect to a predetermined engine rotation speed, and length change control of the variable length intake pipe according to the output of the signal generation means. a first control means for performing;
a second control means for controlling the opening and closing of the opening/closing control valve in accordance with the output of the signal generating means; and a determining means for outputting an output that determines whether the output of the signal generating means is in a gradually increasing direction or in a gradually decreasing direction. , the output of the signal generation means is delayed by a different predetermined time according to the output of the discrimination means, and the control means is provided in parallel between the signal generation means and the first control means or the second control means. 1. A control device for an internal combustion engine having a variable length intake pipe, comprising a first delay means and a second delay means.