JPS6334057B2 - - Google Patents

Description

[Detailed description of the invention]

[Object of the Invention] (Industrial Application Field) The present invention relates to an automatic clutch control device for coupling a driven shaft to a driving shaft of a clutch, and in particular,
This invention relates to initial clutch engagement force control when the clutch is engaged. (Prior Art) In a conventional automatic clutch device, in the initial clutch control when the clutch is engaged when the vehicle is started,
The clutch engagement force (degree of engagement) is determined according to the engine speed, and the clutch is turned on/off during a shift operation after the vehicle has started. If there is a difference between the engine rotational speed (the rotational speed of the clutch drive shaft) and the rotational speed of the clutch driven shaft, fully engaging the clutch in a short period of time will cause a sudden load on the engine and a sudden loss of vehicle driving force. As the vibration increases, shocks or vibrations are generated in the vehicle body, etc., and the driver feels uncomfortable. As a means of alleviating this, since the negative pressure in the engine intake manifold corresponds to the rotational speed difference, the engagement force of the clutch is gradually increased at a speed corresponding to this negative pressure to prevent the impact, etc. However,
In this system, the negative pressure differs depending on the individual vehicle, and the time delay in increasing the engagement force of the clutch is large, so there is a problem in that it is not possible to accurately control the clutch engagement as quickly as possible and without causing shocks. Therefore, the automatic clutch control device proposed in Japanese Patent Publication No. 53-26020 calculates the required clutch engagement force corresponding to the operating state of the engine connected to the drive shaft of the clutch and the rotational speed of the driven shaft of the clutch. comprising a calculation means, a signal generation means for generating an electric signal specifying the required clutch engagement force, and an engagement force setting means for setting the engagement force of the clutch in response to the electric signal, the calculation means comprising:
The required engagement force is calculated using the rotation speed of the engine as the main variable and the difference in rotation speed between the clutch driven shaft and the clutch drive shaft (engine output shaft) as a condition variable.
Generally speaking, in a mode in which the vehicle is driven by engine power, the engagement force of the clutch is controlled in response to the engine rotational speed, and in an engine braking mode, the engagement force of the clutch is controlled in accordance with a specific time function. . In the conventional example, the clutch engagement force is determined according to the engine rotation speed (the rotation speed of the clutch drive shaft) when starting the vehicle, and in the conventional example, the clutch engagement force is determined according to the engine rotation speed using the speed difference between the clutch drive shaft and the conventional shaft as a condition variable. In any of the conventional control methods, after the clutch engagement force becomes high to a certain extent, the engine rotation speed shows a change corresponding to the vehicle load and engine power. It will be done accordingly. (Problems to be Solved by the Invention) However, at the point where the clutch starts engaging when the vehicle starts, and immediately thereafter, that is, until a certain engagement force is set in the clutch, a certain amount of shock is unavoidable. For example, when the shift lever is set to drive or reverse and the engine throttle valve is opened smoothly from the idle position, the clutch engagement force will change from the off state corresponding to the idle rotation to the engine throttle valve. The rotation speed increases smoothly as the rotation speed increases, and no impact occurs, but when the throttle valve is opened beyond the idle opening, that is, when the engine rotation speed is higher than the idle rotation speed, the shift lever is set to drive or reverse. Then, vehicle load (road condition)
Irrespective of this, the clutch engagement force is set to a relatively high engagement force, and at this time a start shock occurs, the engine rotational speed rapidly decreases, and the clutch engagement force is accordingly rapidly changed to a low value. This also causes an oscillatory transient in which the engine speed increases and the clutch is placed at a higher engagement force. The present invention aims to make the start of the vehicle smoother, and in particular, to make the increase in vehicle speed smoother at the beginning of the start of the start.
With the goal. [Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a method that corresponds to the operating state of the engine coupled to the drive shaft of the clutch and the rotational speed of the driven shaft of the clutch. Comprising a calculation means for calculating the required clutch engagement force, a signal generation means for generating an electric signal specifying the required clutch engagement force, and an engagement force setting means for setting the engagement force of the clutch in response to the electric signal. In an automatic clutch control device, means for detecting the rotational speed of the driving shaft of the clutch, means for detecting the rotational speed of the driven shaft of the clutch, and designating a predetermined minute engagement force when the rotational speed of the driven shaft of the clutch is 0. initial minute engagement instructing means that generates an electric signal to specify the predetermined minute engagement force and applies it to the engagement force setting means for a predetermined time; change rate detection means for detecting a change rate of the rotational speed of the drive shaft of the clutch when the rotational speed is applied to the clutch;
Initial engagement instructing means is provided for generating an electric signal specifying a clutch engagement force corresponding to the rate of change and applying it to the engagement force setting means. (Function) When the vehicle is about to start, that is, when the rotational speed of the clutch driven shaft is 0, the initial minute engagement instruction means generates an electric signal specifying a predetermined minute engagement force and sends it. The engaging force is applied to the engaging force setting means for a predetermined period of time. As a result, the driven shaft of the clutch is coupled to the drive shaft with the predetermined minute engagement force, which applies a certain load to the engine corresponding to the vehicle load, and the rotational speed of the engine (the rotational speed of the clutch drive shaft) is applied to the engine in response to this load. ) decreases. The rate of change detection means detects the rate of decrease (rate of change) in the engine rotational speed at this time, and the initial engagement instruction means generates an electric signal specifying a clutch engagement force corresponding to this rate of change. applied to the engagement force setting means. Therefore, the clutch engagement force is determined to correspond to the rate of change in the engine speed, that is, to the vehicle load. The minute engagement force may be so small that the load on the clutch driven shaft is transmitted to the clutch drive shaft for vehicle load determination, and is not necessary to start the vehicle. There is no starting shock. Thereafter, the clutch engagement force corresponding to the above-mentioned rate of change brings about a smooth start that corresponds to the vehicle load (engine load), so the vehicle starts to start without any particular shock. In this way, the present invention sets a minute engagement force on the clutch when attempting to start, detects the rate of change in engine speed due to this, determines the vehicle load, and determines the clutch engagement force corresponding to this. ,
It is possible to start smoothly without causing a start shock. Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings. (Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an apparatus according to an embodiment of the present invention, with emphasis placed on the combination with an engine and a clutch on a vehicle. engine 1
A throttle opening sensor 12 is connected to the rotating shaft of the throttle valve 11 of No. 0, a rotation sensor 20 is connected to the drive shaft (engine output shaft) of the clutch 30, and a rotation sensor 40 is connected to the driven shaft. combined. Clutch 30 is disclosed, for example, in U.S. Pat.
2738864 and U.S. Pat. No. 4,242,924, the piston is equipped with an electromagnetic pressure regulating valve 60 and an on-off valve 50.
Hydraulic pressure is applied according to the operating state of the Note that the on-off valve 50 is omitted and the pressure regulating valve 60 is fully closed (valve closed).
It may also be a controllable pressure regulating valve. Alternatively, the clutch 30 may be an electromagnetic clutch such as that disclosed in U.S. Pat. Other electrically controlled clutches may also be used. The shift lever that sets the operating mode of the transmission is equipped with a position sensor 1 that detects the set position.
3 are combined. The detection signal of the throttle opening sensor 12, the detection signal of the rotation sensors 20 and 40, and the shift lever position detection signal are subjected to digitization processing such as amplification, waveform shaping, and digital conversion at an interface (electrical processing circuit) 70. and applied to the microprocessor system 90. Connected to the interface 70 is a manual set switch 14 for instructing half-clutch operation, such as half-clutch operation during road congestion, and its set state signal is provided to the microprocessor unit 90. The microprocessor unit 90 has a semiconductor read-only memory (ROM or PROM) that stores a clutch control signal group, and includes clutch drive shaft rotation speed N _e , driven shaft rotation speed No., throttle opening Tθ, and shift lever position. reading the system S _p , etc., accessing the semiconductor read-only memory, reading the clutch control data, and using the interface 7.
0 to control the pressure regulating valve 60. FIG. 2 shows the overall configuration of an embodiment of the present invention, and FIGS. 3a to 3e show details of each part. First, the clutch drive shaft rotational speed detection system will be explained with reference to FIGS. 2 and 3a. A permanent magnet gear is fixed to the clutch drive shaft, with a large number of teeth formed on the outer periphery, and adjacent teeth are magnetized with opposite polarities.A magnetic core around which a sensor coil is wound is placed opposite the teeth. The magnet gear, the magnetic core, and the sensor coil constitute the rotation sensor 20. When the magnetic gear rotates, an alternating voltage is induced in the sensor coil, which is applied to the amplification/waveform shaping circuit 72 of the interface 70 . In the circuit 72, the first operational amplifier OP1 inverts and amplifies the input alternating voltage, and the second operational amplifier OP1 inverts and amplifies the input alternating voltage.
2 performs inversion amplification and level shift adjustment, and the first and second transistors perform binarization and inversion amplification. As a result, a speed detection pulse having a frequency and a pulse width corresponding to the rotational speed of the magnet gear 20 is applied to the mono-multivibrator MM1. The mono-multivibrator MM1 is triggered by the rising edge of the speed detection pulse and outputs a high-level "1" pulse with a constant short width. The output of mono-multivibrator MM1 thereby produces an engine speed detection pulse of constant pulse width and a frequency proportional to the rotational speed of the clutch drive shaft. The engine speed detection pulse is applied to counter latch circuit 74 of interface 70 via NAND gate NA1. Counter latch circuit 74
is 4-bit counter CO1, CO2, latch LA
1 and an OR gate OR1, a counter CO1 counts engine speed detection pulses, and a counter CO2 counts carry pulses of the counter CO1. i.e. counter CO
1 and CO2 make up an 8-bit counter.
The count codes of the counters CO1 and CO2 are updated and stored in the latch LA1 at predetermined intervals, and the counters CO1 and CO2 are cleared every time the memory is updated.
Therefore, the memory data of latch LA indicates the number of engine speed detection pulses during a predetermined period, that is, the engine rotational speed. A timer circuit 73 controls updating of the memory of latch LA1 and clearing of counters CO1 and CO2. The timer circuit 73 counters the oscillation pulses of the pulse oscillator OSC.
The frequency is divided by CO3 and NAND gates NA2 and NA3 to form a latch instruction pulse and a counter clear instruction pulse, and the counter clear instruction pulse is converted into a short pulse by mono multivibrator MM2 to energize latch LA1 (memory update). Next, counters CO1 and CO2 are momentarily cleared. Next, the clutch driven shaft rotational speed detection system and the clutch driven shaft rotational direction detection system will be explained with reference to FIGS. 2 and 3b. The clutch driven shaft has
A permanent magnet gear similar to the permanent magnet gear of the sensor 20 is connected, and two magnetic cores 41 and 42 each having a detection coil wound thereon are oppositely connected to the permanent magnet gear, and the two magnetic cores 41 and 42 have a π They are arranged in a relationship that produces an induced voltage having a phase difference of /2. The induced voltages of the detection coils wound around the magnetic cores 41 and 42 are applied to amplification/waveform shaping circuits 75 and 76, respectively. The configuration of the circuit 75 is the same as that of the circuit 72 described above, and the circuit 75
has a configuration in which the mono-multivibrator MM1 is omitted from the circuit 72. The output pulse of the circuit 75, that is, the clutch driven shaft rotational speed detection pulse, is applied to a counter latch circuit 77 having the same configuration as the counter latch circuit 74. The latch instruction pulse and the counter clear instruction pulse applied to the circuit 74 are similarly applied to the circuit 77 by the timer circuit 73. The latch memory data therefore indicates the clutch driven shaft rotational speed.
The rotation detection pulses _Npp1 and _Npp2 of the amplification/waveform shaping circuits 75 and 76 have a phase difference of π/2, and are applied to the direction determining element FF2 of the rotation direction determining circuit 78. The direction determining element FF2 is a JK flip-flop, and depending on the phase difference between the rotation detection pulses _Npp1 and _Npp2 , it is set to a low level "0" when the rotation of the clutch driven shaft corresponds to the forward direction of the vehicle.
When it corresponds to the reverse direction, a high level "1" is output. FIG. 3c shows an outline of the configuration of the throttle opening sensor 12 and a processing circuit 71 (part of the interface 70) that processes its detection signal. In the throttle opening sensor 12, there are 5
electrodes 12a ₁ to 12a ₅ are formed. A slider electrode formed with five radially extending brush arms 12b ₁ to 12b ₅ is fixed to a rotating shaft connected to the throttle valve rotating shaft and electrically connected to ground potential. Throttle valve opening 0
The rotation range from % to 100% is less than 360°/5, and the brush arms 12b ₁ -12b ₅ are separated from each other by an angle of 360°/5. The first electrode 12a ₁ is connected to the first arm 12b ₁ when the opening degree is from less than 0% to less than 5%.
The second electrode 12a 2 has a width that contacts the second arm 12b ₂ from less than 5% to 35%, _{and the third electrode 12a 3 has} a width from less than 35% to less than 35%.
The fourth electrode _{12a 4 has a width that contacts the third arm 12b 4 within} 60% to 80%, and the fifth electrode 12a ₅ has a width that contacts the fifth arm 12b ₅ from less than 60% to more than 100%. As described above, in order to avoid a situation in which none of the arms 12b ₁ to 12b ₅ comes into contact with any of the electrodes 12a ₁ to 12a ₅ , the arm 12b ₁ does not touch the electrodes at the opening degree of 5% and on the slightly lower opening side. 12a ₁ ,
The arms 12b ₂ and 12b ₃ contact the electrodes 12a ₂ and 12a _{3, respectively, when the opening degree is 35% and slightly lower, and the arms 12b 2 and 12b 3} are in contact with the electrodes 12a ₂ and 12a ₃ , respectively, and when the opening degree is 60% and slightly lower. On the degree side, arms 12b ₃ and 12b ₄ contact electrodes 12a ₃ and 12a ₄ , respectively, and further, on the 80% opening side and slightly lower opening side, arms 12b ₄ and 12b ₅ contact electrodes 12a ₄ and 12a ₅ , respectively. I try to do that. As a result, both electrodes may be at ground level at the same time. However, in order to uniquely determine the opening detection signal even in such a state, the processing circuit 71 amplifies the potential of the electrodes 12a ₁ to 12a ₅ , and then uses the inverters IN1 to IN4 and the OR gates OR2 to OR5 to detect the opening on the low opening side. The detection signal is output with priority. Throttle opening Tθ
% throttle opening Tθ detection code
Shown in the table.

[Table] Next, install the shift lever position detection system to the 3d
This will be explained with reference to the figures. The shift lever position sensor 13 is composed of a switch 13 ₁ that is closed when the gear is in neutral (N) and a switch 13 ₂ that is closed when it is in reverse (R). These switches are connected to an amplifier circuit 79 of the interface 70. An instruction switch or manual set switch 14 for extending the half-clutch state is connected to flip-flop FF1. The correlation between the opening/closing of these switches and the status display code is shown in Table 2 below. In addition, flip-flop
FF1 is set by closing switch 14, and microprocessor unit 90 resets it.

[Table] Next, the remaining parts of the interface 70, that is, the solenoid driver 80 and D/A converter 81 that energize the on-off valve 50, and the solenoid driver 82 that energizes the pressure regulating valve 60 are shown in FIG. 3d. Explain with reference to. Microprocessor unit 90 outputs and latches the clutch control signals to its output ports _O0 - _O12 . Of these, what is output to _O0 is the opening/closing control signal for the on-off valve 50, what is output to _O1 is the flip-flop FF1 reset control signal, and what is output to _O2 is the flip-flop FF1 reset control signal.
~ _O12 is a pressure regulating valve control signal, that is, clutch energization control data. In the solenoid driver 80, the on-off valve control signal _O0 is applied to the mono multivibrator MM3 and the NAND gate.
Applied to NA4. At Nand Gate NA4,
The timing pulse D and the output of the mono-multivibrator MM3 are further applied from the timer circuit 73 (FIG. 3a). Therefore, when the signal _O0 becomes a high level "1" instructing the opening of the valve 50, its output is at a low level "0" during the set time period of the mono multivibrator MM3, and the NAND gate
The output of NA4 is continuously at a high level "1", transistor T _r3 is restrained off, transistors T _r4 and T _r5 are both conductive, and the solenoid of the on-off valve 50 is continuously energized. The plunger 50 is driven with a strong force in the valve opening direction, and the valve 50 is opened. When the output of the mono multivibrator MM3 returns to the high level "1" after a predetermined period of time has elapsed, the output of the NAND gate NA4 fluctuates between high and low according to the timing pulse D. The duty of this pulse variation is 50%. Therefore, the transistor T _r5 repeats on and off in synchronization with the pulse fluctuation of the timing pulse D, and the current flowing through the solenoid of the on-off valve 50 is reduced by half on a time average. However, since the plunger of the on-off valve 50 has already moved to the open position and is in contact with the suction yoke, it still remains in the valve open position. That is, at the beginning of driving the plunger, the solenoid energization level is increased to increase the driving force, and after the plunger is driven to open, the energization level is decreased to reduce the heat generation of the solenoid. An energization energizing analog signal instructed by a clutch control code (hereinafter referred to as a C _p code) is applied to the solenoid driver 82 from the D/A converter 81 . Transistor T _r6 controls the conductivity of transistor T _r7 according to the analog signal level. The solenoid of the pressure regulating valve 60 is therefore applied with a current at the level indicated by the C _p code, and the plunger of the valve 60, which has a throttle opening, remains in a position corresponding to the solenoid energization level. The configuration of the power supply device 110 is shown in FIG. 3d. The voltage of 12V of the main power battery on the vehicle is determined by the constant voltage element 111.
The voltage is stepped down to 5V and made constant, and then DC/
The DC converter 112 boosts the voltage to 30V. the
The intermediate 15V between 30V and 15V is applied to the D/A converter 81 as the ground level. The configuration of the microprocessor unit 90 is
Shown in Figure e. This microprocessor unit 9
0 is a microprocessor (hereinafter referred to as CPU)
91, semiconductor read-only memory with input/output ports (hereinafter referred to as ROM) 92, 93, and semiconductor read/write memory with input/output ports (hereinafter referred to as RAM) 94. Reset circuit 10
0 is applied with a power supply of 5V. Reset circuit 10
0, a reset instruction signal is given to the CPU 91 immediately after the power supply of 5V is applied, and thereafter when the reset switch 101 is closed.
The CPU 91 initializes the input/output ports in response to this reset instruction signal. Among the elements explained above, the main IC elements are shown in Table 3 below.

〔Effect of the invention〕

As described above, the automatic clutch control device of the present invention has the following features:
Calculating means 9 for calculating the required clutch engagement force corresponding to the operating state of the engine connected to the drive shaft of the clutch 30 and the rotational speed of the driven shaft of the clutch.
0, signal generation means 90, 81 for generating an electric signal specifying the required clutch engagement force, and engagement force setting means 80, 82, 50, 60 for setting the engagement force of the clutch in response to the electric signal. An automatic clutch control device comprising: means 20 for detecting the rotational speed of the driving shaft of the clutch; means 40 for detecting the rotational speed of the driven shaft of the clutch; An electric signal (Vs ₂ ) specifying the engagement force is generated and applied to the engagement force setting means 80, 8 for a predetermined period of time.
Initial minute engagement instruction means 9 given to 2, 50, 60
0. Rotation of the drive shaft of the clutch when the initial minute engagement instruction means 90 is applying an electric signal (Vs ₂ ) specifying the predetermined minute engagement force to the engagement force setting means 80, 82, 50, 60; change rate detection means 90 for detecting the rate of change in speed (dNe/dt);
and an electric signal [Cp=Vsx=
f (i, j, k, l)] and applies this to the engagement force setting means 80, 82, 50, 60, when the vehicle is about to start. In other words, when the rotational speed of the clutch driven shaft is 0, the initial minute engagement instruction means 90 generates an electric signal (Vs ₂ ) specifying a predetermined minute engagement force and maintains the engagement force for a predetermined period of time. The setting means 80, 82, 50, and 60 are given. As a result, the driven shaft of the clutch 30 is coupled to the drive shaft with the predetermined minute engagement force, which applies a certain load to the engine corresponding to the vehicle load, and the rotational speed of the engine (the rotation of the clutch drive shaft) is applied to the engine in response to this load. speed) decreases. The change rate detection means 90
detects the rate of decrease (rate of change) (dNe/dt) of the engine rotational speed (Ne) at this time, and the initial engagement instruction means 90 specifies the clutch engagement force corresponding to this rate of change (dNe/dt). Electrical signal [Cp=
Vsx=f(i, j, k, l)] and applies it to the engagement force setting means 80, 82, 50, 60. Therefore, the clutch engagement force is determined to correspond to the rate of change (dNe/dt) of the engine rotational speed, that is, to the vehicle load. The minute engagement force may be so small that the load on the clutch driven shaft is transmitted to the clutch drive shaft in order to determine the vehicle load when starting.
It is not necessary to actually start the vehicle,
This minute engagement force does not cause a starting shock. After that, the rate of change (dNe/dt)
Since the clutch engagement force corresponding to the above causes a smooth start in accordance with the vehicle load (engine load), the vehicle starts to start without any particular shock. In this way, the present invention sets a minute engagement force on the clutch when attempting to start, detects the rate of change in engine speed (dNe/dt) caused by this, determines the vehicle load, and applies a corresponding clutch force. Since the engagement force is determined, smooth start can be performed without causing a start shock.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an outline of the configuration of an embodiment of the present invention in combination with a vehicle. FIG. 2 is a block diagram showing the overall structure of this embodiment of the present invention in slightly more detail. Figure 3a, Figure 3b, Figure 3c
3d and 3e are electrical circuit diagrams showing in detail the construction of each of the blocks shown in FIG. 2. FIG. 4 is a graph showing an overview of clutch control data stored in the ROMs 92 and 93. Figures 5a, 5b, 5c and 5
Figure d is a graph showing part of the data shown in Figure 4, and shows data for flat road start control, uphill road start control, severe uphill road start control, and engine brake control, respectively. . Figure 6a,
Figures 6b, 6c, 6d, 6e, 6
FIG. 6f, FIG. 6g, FIG. 6h and FIG. 6i are flowcharts showing the clutch control operation of the CPU 91 based on the program data of the ROMs 92 and 93, respectively. FIGS. 7a, 7b, and 7c are graphs showing changes in the engine rotational speed Ne when starting on a flat road, starting on an uphill road, and starting on a steep uphill road, respectively. FIG. 7d is a graph showing changes in clutch driven shaft rotational speed N ₀ during engine brake control. FIGS. 8a and 8b are graphs showing clutch-on control characteristics when the vehicle load and throttle opening change in a half-clutch state. FIG. 8c is a graph showing the engine brake setting possible region and the impossible region. FIG. 8d is a graph showing the clutch-on control characteristics when the clutch is set in a manual half-clutch position. FIG. 8e is a graph showing clutch on/off regions with respect to throttle opening and engine speed. 10: Engine, 11: Throttle valve, 1
2: Throttle opening sensor, 14: Manual set switch, 13: Shift lever position sensor,
20: Clutch drive shaft rotation sensor (means for detecting the rotation speed of the clutch drive shaft), 40: Clutch driven shaft rotation sensor (means for detecting the rotation speed of the clutch driven shaft), 50: Opening/closing valve, 60:
Pressure regulating valve, 70: Input/output interface, 8
0: Solenoid driver, 81: D/A converter, 82: Solenoid driver (80, 82, 5
0, 60: engagement force setting means), 90: microprocessor system (calculation means, initial minute engagement instruction means, change rate detection means, initial engagement instruction means)
(90, 81: signal generation means), 91: microprocessor, 92, 93: ROM, 94: RAM.

Claims (1)

[Scope of Claims] 1. Calculating means for calculating the required clutch engagement force corresponding to the operating state of the engine coupled to the drive shaft of the clutch and the rotational speed of the driven shaft of the clutch;
An automatic clutch control device comprising a signal generating means for generating an electric signal specifying the required clutch engagement force, and an engagement force setting means for setting the engagement force of the clutch in response to the electric signal: Driving the clutch. means for detecting the rotational speed of the shaft; means for detecting the rotational speed of the driven shaft of the clutch; generating an electric signal specifying a predetermined minute engagement force when the rotational speed of the driven shaft of the clutch is 0; initial minute engagement instructing means for applying to said engagement force setting means for a period of time; driving said clutch when said initial minute engagement instruction means is giving an electric signal to said engagement force setting means specifying said predetermined minute engagement force; Change rate detection means for detecting the change rate of the rotational speed of the shaft; and initial engagement instruction means that generates an electric signal specifying a clutch engagement force corresponding to the change rate and supplies it to the engagement force setting means; An automatic clutch control device comprising: