JPH0643852B2 - Control method for electromagnetic clutch for vehicle - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for controlling an electromagnetic clutch for a vehicle, and more particularly to a control technique for adjusting torque in an engaging process of the electromagnetic clutch.

2. Description of the Related Art A magnetic powder type electromagnetic clutch is a type of clutch that is inserted in a power transmission path from a vehicle engine to driving wheels. Since such a magnetic powder type electromagnetic clutch can obtain a transmission torque having a magnitude corresponding to the exciting current supplied to the exciting coil, it is possible to obtain smooth engagement similar to that of the fluid clutch by using a control means such as a microcomputer. It is automatically obtained without requiring, and because there is no slip during running,
The same fuel efficiency as when using the friction clutch is obtained. In the half-clutch control of such a magnetic powder type electromagnetic clutch, in order to improve the fuel consumption efficiency by smoothing the engagement and improving the drivability at the time of starting the vehicle, and further suppressing the input side rotation speed at the time of engagement, For example, various control equations have been devised as shown in the following equations (1) and (2).

Tcl = K (θ, N ^* ) (Ne-Nid1) (1) where Tcl is transmission torque, K is feedback gain, θ is throttle valve opening, N ^* is target meat rotation speed, and Ne is engine. The rotation speed and Nidl are idle rotation speeds.

Tcl = Te (θ, Ne) + k ₁ (Ne−N ^* ) + k ₂ ∫ (Ne−N ^* ) dt (2) where Te is the output torque of the engine, k ₁ is a proportional control constant, k ₂ is an integral control constant.

Using the above control formula (1), Japanese Patent Application No. 59-133491
As described in detail in the publication, a desired meat rotation speed can be obtained for any throttle valve opening within a predetermined range. In other words, regardless of the throttle valve opening,
The electromagnetic clutch is half-clutched so that a constant target meat rotation speed N ^* is maintained. In the control formula (2), the instantaneous value Te of the engine output torque is set to improve the transient response.
In addition to the term corresponding to, the second and third terms are provided as feedback control terms for the meat rotation speed,
Feedback control is performed so that the target meat rotation speed and the actual engine rotation speed Ne are approximate to each other. That is,
Even in this case, the predetermined target meet rotation speed N ^* can be obtained by the half-clutch control regardless of the throttle valve opening. Therefore, by using the control expressions (1), (2), etc., suitable half-clutch control can be obtained regardless of the throttle valve opening.

In addition, JP-A-60-23639 and JP-A-60-3
As described in Japanese Patent No. 7425 or the like, a control device for a magnetic powder type electromagnetic clutch has been proposed in which the target meat rotation speed is determined according to the throttle valve opening.
According to this, the larger the depression amount of the accelerator pedal, the higher the target meat rotation speed and the higher the driving force at the time of starting, so as compared with the case where a constant target meat rotation speed is used as described above. The drivability at the time of starting the vehicle is improved.

Problems to be Solved by the Invention By the way, according to the above-mentioned conventional control method, the target meat rotation speed is uniquely determined with respect to the throttle valve opening, so that the starting acceleration is sufficient for the driver who attaches importance to drivability. In addition, the fuel consumption rate may not be sufficient for drivability that places importance on economic efficiency, and the acceleration response at the start when the driver desires may not always be obtained.

The present invention has been made in the background of the above circumstances,
It is an object of the invention to provide a method of controlling an electromagnetic clutch that can obtain acceleration responsiveness at the time of starting according to a driving performance selection operation by a driver.

Means for Solving the Problems The gist of the present invention for achieving such an object is to provide an electromagnetic clutch to the electromagnetic clutch so that the input side rotational speed becomes a target meat rotational speed when the vehicle equipped with the electromagnetic clutch starts. When controlling the exciting current to be supplied, the target meat rotation speed is determined based on a value related to the throttle valve opening of the vehicle or a value related to the changing speed of the throttle valve opening from a predetermined relationship. The target meat rotation speed is corrected in response to the operation of the travelability selection switch for selecting the travelability of the vehicle.

In this way, the target meat rotation speed is determined based on the value related to the throttle valve opening of the vehicle or the value related to the changing speed of the throttle valve opening, and the running property of the vehicle is selected. Since the target meat rotation speed is corrected in response to the operation of the running property selection switch, the acceleration responsiveness at the time of starting is obtained according to the running property selecting operation of the driver.
That is, a driver who attaches importance to drivability can obtain sufficient start-up acceleration by selecting power traveling with the drivability selection switch, but a driver who attaches importance to economy selects economic traveling with the drivability selection switch. As a result, it is possible to obtain a gentle start-up acceleration characteristic and fuel consumption efficiency.

Further, the target meat rotation speed is increased and corrected in accordance with the decrease in the engine output. For example, in a cold engine, since the output torque is small even at the same rotation speed, such an increase correction makes it possible to obtain the same drivability as in the warm-up state.

Further, the target meat rotation speed is preferably corrected according to a change in running resistance of the vehicle. The running resistance of the vehicle changes depending on the slope resistance due to the inclination of the road surface, the acceleration resistance due to the vehicle weight, the rolling resistance due to the road friction coefficient, the steering angle of the steering wheel, etc. Even if the engine output is constant, such running resistance changes Since the drivability changes according to the above, even if there is a change in the running resistance due to such a correction, a suitable drivability can be obtained in the same way as when starting on a level ground, when starting an empty vehicle, when starting a paved road surface, etc. .

Here, the meat rotation speed, in the half-clutch control of the magnetic powder type electromagnetic clutch, there is a phenomenon that the input side rotation speed of the magnetic powder type electromagnetic clutch continues at a substantially constant value, such a constant value is called the meat rotation speed. Of. Assuming that the input side of the magnetic powder type electromagnetic clutch is directly connected to the engine, the equation of motion of the crankshaft of the engine is expressed by the following equation (3). In this equation (3), magnetic powder type Ie = Te-Tcl (3) where I is the moment of inertia of the crankshaft including the flywheel, e is the rotational acceleration of the engine, and Te is the output torque of the engine. , Tcl are transmission torques of the magnetic powder type electromagnetic clutch.

When the magnetic clutch is engaged, the engine rotation speed Ne becomes constant and becomes e0, so Te = Tcl, and the engine torque determined by the throttle valve opening and the meat rotation speed at that time is transmitted. Therefore, in the half-clutch state, controlling the meat rotation speed is nothing but controlling the transmission torque Tcl.

Examples Hereinafter, one application example of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a magnetic powder type electromagnetic clutch 16 is provided between a crank shaft 12 of an engine 10 and an input shaft 14 of a transmission (not shown). The magnetic powder type electromagnetic clutch 16 is provided with a flywheel 18 fixed to the shaft end of the crankshaft 12 on the input side, as shown in FIG.
The flywheel 18 includes an annular yoke 20. An annular excitation coil 22 is provided at the center of the yoke 20.
Is embedded in the excitation coil 22 and the yoke 20
An exciting current is supplied from a power supply brush (not shown) via a slip ring 24 that rotates together with it. The rotor 26 has a bearing 28 inside the yoke 20.
It is rotatably supported by the first labyrinth member 30 via. The first labyrinth member 30 is fixed to one end surface of the yoke 20, and the yoke 2
An annular protrusion 32 for sealing magnetic particles to be filled by a magnetic force is fixed to a gap formed between the inner peripheral surface of the rotor 0 and the outer peripheral surface of the rotor 26. The annular projection 32 and the second labyrinth member 34 provided on the other end surface of the yoke 20 form a substantially sealed annular space to prevent leakage of magnetic particles. This magnetic powder is filled in the gap between the inner peripheral surface of the yoke 20 and the outer peripheral surface of the rotor 26 when a magnetic field is formed in accordance with the exciting current flowing in the exciting coil 22, and the crankshaft follows the characteristics shown in FIG. The torque of 12 is transmitted to the input shaft 14. The input shaft 14 is spline-fitted to the hub 36 at its shaft end, and the hub 36 is connected to the rotor 26 via a damper 38 for absorbing an engagement shock. The driving force transmitted to the input shaft 14 is transmitted to the driving theory of the vehicle via a transmission, a differential device, etc., which is a continuously variable transmission or a stepped transmission.

Returning to FIG. 1, the throttle valve provided in the intake pipe of the engine 10 is provided with a throttle sensor 42 for detecting the opening degree θ of the throttle valve. The throttle sensor 42 constitutes a required output detecting means required by the driver, and the throttle signal Sθ representing the throttle valve opening θ that reflects the driver's intention is an A / D converter 46 in the controller 44. Is supplied to. From the igniter 48 attached to the engine 10,
Ignition signal S corresponding to the ignition pulse for the engine 10
I is supplied to the I / F circuit 50 in the controller 44. The I / F circuit 50 converts the ignition signal SI into an ignition cycle T _ig for calculating the engine rotation speed Ne. The controller 44 is composed of a so-called microcomputer called an ECU, and has a CPU 52, a ROM 54, a RAM 5
6 is provided. The CPU 52 executes signal processing in accordance with a program stored in advance in the ROM 54 while utilizing the temporary storage function of the RAM 56, and supplies the control voltage Vcl to the amplifier 60 via the D / A converter 58. The amplifier 60 applies a voltage corresponding to the control voltage Vcl to the exciting coil 22, and the exciting current Icl is passed through the exciting coil 22. The exciting current Icl is a value corresponding to the control voltage Vcl because the winding resistance of the exciting coil 22 is substantially constant. But,
Instead of the amplifier 60, a constant current circuit may be provided to flow the exciting current Icl corresponding to the control voltage Vcl by current feedback regardless of the change in the impedance of the exciting coil 22.

The target meet rotation speed setting device 62 is connected to the data bus line of the controller 44. The target meet rotation speed setter 62 includes a runnability selection switch 6
4, engine temperature sensor 66, steering wheel angle sensor 6
8, output signals from the road surface gradient sensor 70, the vehicle weight sensor 72, and the road surface friction sensor 74 are supplied. The runnability selection switch 64 is used to switch runnability such as economical run, normal run, and power run by operating an operating body (not shown), and outputs a signal indicating the selected runnability. The engine temperature sensor 66 detects the temperature of the engine 10, for example, its cooling water temperature, and outputs a signal representing the temperature. The steering wheel steering angle sensor 68 detects the steering wheel steering angle of the vehicle and outputs a signal representing the steering wheel steering angle. The road surface gradient sensor 70 detects the road surface gradient on which the vehicle is located, and outputs a signal representing the road surface gradient.
The vehicle weight sensor 72 is provided, for example, in the suspension of the vehicle to detect the loaded weight of the vehicle, and outputs a signal representing the weight. The road surface friction sensor 74 detects a friction coefficient of a road surface such as a paved road, a gravel road, a snow road, and a rainy road, and outputs a signal representing the friction coefficient. The target meat rotation speed setting device 62 is configured by a so-called CPU, processes a signal supplied according to a program previously stored in the ROM 54, and outputs the target meat rotation speed N.
^* Decide.

The operation of this embodiment will be described below.

First, step S1 of FIG.
The idle rotation speed Nidl is learned and stored by executing a predetermined algorithm. Next, step S2 is executed and whether or not the accelerator operation is performed, in other words, whether or not the throttle valve opening degree θ already read by a step (not shown) is larger than a predetermined small value. Is determined based on the throttle signal Sθ. When it is determined that the accelerator operation is not performed, step S3 is executed and the transmission torque T to be controlled is
Set cl to zero. However, if it is determined that the accelerator operation is performed, step S4 is executed and the target meat rotation speed N ^* is read. The target meat rotation speed N ^* is sequentially determined by the target meat rotation speed setter 62.

In the target meat rotation speed setting device 62, for example, a target meat rotation speed determination routine shown in FIG. 5 is repeatedly executed. That is, in step SW1, the throttle valve opening θ is read based on the throttle signal Sθ, and in step SW2 it is determined whether or not the content of the flag is “1”. The flag F indicates that the change speed of the throttle valve opening is calculated in one starting operation of the vehicle, and is reset by a step (not shown) each time the starting operation is completed. Normally, immediately after the start operation, the change rate of the throttle valve opening is not calculated and the content of the flag F is "0", so steps SW3 and SW4 are executed. In step SW3, "1" is added to the content of the counter I, and in step SW4 it is determined whether or not the content of the counter I has reached a predetermined constant value α. This α corresponds to, for example, about 100 _msec, and corresponds to a time span for calculating the throttle valve opening change speed in one starting operation of the vehicle. Immediately after the start operation, the content of the counter I does not reach α, so step SW5 is executed and the transmission torque Tcl to be controlled is set to “0”. However, when the content of the counter I reaches α, step SW6 is executed, and the throttle valve opening θ at that time and the elapsed time until that time (a time span corresponding to α is about 1
00m _sec) the throttle valve opening change rate is calculated from, and the flag F while being stored is set to "1".

In the following step SW7, the target meet rotation speed N ^* is determined from the relationship obtained in advance from the current throttle valve opening θ and the throttle valve opening change speed obtained in step SW6. FIG. 6 shows an example of the relationship obtained in advance used in step SW7, which is stored in the ROM 54 in the form of a data map in advance.
The target meat rotation speed N ^* is appropriately determined between the data of the data map using a means such as linear interpolation. In addition,
The relationship shown in FIG. 6 is stored in the ROM 54 in advance in the form of a functional formula, and the target meat rotational speed N ^* is stored using the functional formula ^.
May be calculated.

Each correction value is determined in step SW8. The correction value ΔN ^* _m corresponding to the runnability is determined according to the switching state of the runnability selection switch 64 from the predetermined relationship shown in FIG. 7, for example. As a result, the correction value ΔN ^* _m is greatly increased when the vehicle is switched to the power running, so that the starting acceleration is significantly improved, while the correction value ΔN ^* _m is changed when the traveling property selection switch 64 is switched to the economy traveling. It is made smaller, and a highly economical starting run can be obtained. The correction value ΔN ^* _t corresponding to the engine water temperature is obtained, for example, from the predetermined relationship shown in FIG. As a result, the correction value ΔN ^* _t is increased as the engine becomes colder when a sufficient output is not obtained, and the drivability at the time of starting is maintained as in the case of warming up. Correction value ΔN ^* corresponding to the steering angle
_h is obtained from the predetermined relationship shown in FIG.
As a result, the correction value ΔN ^* _h is increased as the traveling resistance increases with an increase in the steering wheel turning angle, so that the engine 10 can be prevented from stopping even when the steering wheel is fully turned and the vehicle starts. Based on the relationship shown in FIG. 10, the correction value ΔN ^* _r corresponding to the road surface slope is increased in a substantially positive direction in which the road surface slope (tan θ) increases in the positive direction, and conversely, the larger the correction value ΔN ^* _r in the negative direction, the larger the negative value. The value of. As a result, the necessary and sufficient engine output similar to that on a flat road can be obtained even when the running resistance changes due to the road gradient, and suitable drivability is ensured regardless of the road gradient. The correction value ΔN ^* _w corresponding to the vehicle weight is the first
Based on the relationship shown in FIG. 1, the larger the vehicle weight, the larger the vehicle weight. As a result, the correction value ΔN ^* _w is increased as the vehicle weight increases and a decrease in the starting acceleration is predicted, so that the drivability at the time of starting is secured as in the case of an empty vehicle. Further, the correction value ΔN ^* _μ corresponding to the road surface frictional resistance is obtained from the predetermined relationship shown in FIG. 12, for example. In the relationship shown in FIG. 12, the correction value ΔN ^* _μ, which reduces the road surface friction coefficient μ, is a negative value, so on road surfaces such as snow roads, gravel roads, and wet road surfaces where the friction coefficient is small, The transmission torque is minimized to prevent slipping when the vehicle starts. At this time, the smaller the road surface friction coefficient μ, the smaller the target meat rotation speed N ^*, but this lower limit value is restricted by the idle rotation speed Nidl.

In step SW9, the total correction value according to the following equation (4) Is determined.

However, δ is a function of the fixed torque Te of the engine 10, the target meet rotation speed N ^* , the throttle valve opening θ, the desired transmission torque Tcl or a constant time, and is a negative or positive value.

Then, step SW10 is executed, and the total correction value determined in step SW9 of the current cycle is added to the target meat rotation speed N ^* determined in the previous cycle. Is added, the target meat rotation speed N ^* is updated. Then, the above steps SW1, SW2, S
Target meat rotation speed N by repeating W7 to SW10
^* Is decided sequentially.

Returning to FIG. 4, in step S5, the gain K is calculated based on the relationship obtained in advance from the throttle valve opening θ already read in and the target meet rotation speed N ^* read in step S4. The relationship is shown in FIG. 13, for example, and is stored in the ROM 54 in advance in the form of a data map or a function. Then, step S6 is executed, the actual engine speed Ne is read, and the value of the transmission torque Tcl to be controlled in step S7 is determined based on the control formula. This control equation is, for example, the equation (1). Then, step S8 is executed, the control voltage Vcl for obtaining the transmission torque Tcl obtained in step S7 is determined from the relationship shown in FIG. 3, and the control voltage Vcl is output in step S9.

The transmission torque of the magnetic powder type electromagnetic clutch 16 is sequentially controlled by repeatedly executing the above steps.

Thus, according to the present embodiment, the magnetic powder type electromagnetic clutch 1
In the engagement control of No. 6, the target meet rotation speed N ^* is determined based on the throttle valve opening of the vehicle or the changing speed θ of the throttle valve opening, and the travelability selection switch 64 for selecting the travelability of the vehicle is operated. In response, the target meat rotation speed N ^* is corrected, so that the acceleration responsiveness at the time of starting can be obtained according to the driving performance selection operation of the driver. That is, the driver who attaches importance to drivability selects the drivability selection switch 6
Sufficient start-up acceleration is obtained by selecting power running by means of 4. However, a driver who attaches importance to economy can obtain a moderate start-up acceleration while selecting economical running by using the runnability selection switch 64 and fuel Consumption efficiency can also be obtained.

Although one application example of the present invention has been described above, the present invention can be applied to other modes.

For example, in the above-described embodiment, the control equation for obtaining the transmission torque Tcl may be the equation shown in the equation (2),
In such a case, SS4 to SS7 in FIG. 14 are preferably used instead of steps S4 to S7 in FIG. That is, in step SS4, the actual engine rotation speed Ne is read and
In S5, the actual engine torque Te is calculated from the previously determined relationship based on the throttle valve opening θ and the engine rotation speed Ne. Then, in step SS6, the target meet rotation speed N ^* determined by the target meet rotation speed setter 62 is read, and in step S7, the actual engine rotation speed Ne and the target meet rotation speed are calculated from the control equation shown in the equation (2). The transmission torque Tcl to be controlled is calculated based on the speed N ^* .

Further, in the above embodiment, the target meat rotation speed N
^* Is the total correction value based on the basic value obtained from the relationship shown in FIG. It was decided by adding, but even if such a correction is not made, a temporary effect can be obtained, and the total correction value Is a correction value ΔN ^* _m corresponding to the operation position of the running property selection switch 64, a correction value ΔN ^* _t corresponding to the engine water temperature, a correction value ΔN ^* _h corresponding to the steering angle, and a correction value ΔN ^* corresponding to the road surface gradient ^. _r , correction value ΔN corresponding to vehicle weight
It may be determined using a means such as weighting from any one or more of ^* _w and the correction value ΔN ^* _μ corresponding to the road surface friction coefficient.

Further, in the above-described embodiment, the target meat rotation speed N ^*
The throttle valve opening θ and the rate of change of the throttle valve opening θ are used to determine the value, but the driver's will will be reflected even if the value is determined based on either of the two values. Further, the throttle valve opening may be replaced with an amount representing the output required by the driver, such as the accelerator operation amount.

It should be noted that the above is merely an application example of the present invention, and the present invention can be variously modified without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an apparatus to which the present invention is applied. FIG. 2 is a sectional view showing in detail the magnetic powder type electromagnetic clutch of FIG. FIG. 3 is a diagram showing the transmission characteristics of the electromagnetic clutch of FIG. 4 and 5 are the first
6 is a flowchart illustrating the operation of the apparatus shown in the figure. Sixth
The figure is a diagram showing an example of the relationship used when obtaining the target meat rotation speed in the flowchart of FIG.
FIG. 7 to FIG. 12 are views showing the relationships used when obtaining each correction value in the flowchart of FIG. FIG. 13 is a diagram showing the relationship used when obtaining the gain K in the flowchart of FIG. FIG. 14 is a main part of a flowchart for explaining the operation of another example to which the present invention is applied. 10: engine, 16: magnetic powder type electromagnetic clutch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Shigematsu 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. (56) References JP-A-60-37425 (JP, A) JP-A-60-23639 (JP, A) Actually open Sho 61-88835 (JP, U)

Claims (3)

[Claims] 1. When controlling the exciting current supplied to the electromagnetic clutch so that the input side rotation speed becomes the target meat rotation speed when the vehicle equipped with the electromagnetic clutch starts, the target meat rotation speed is predetermined. In response to the operation of the drivability selection switch for selecting the drivability of the vehicle, it is determined based on the value related to the throttle valve opening of the vehicle or the value related to the changing speed of the throttle valve opening from the above relationship. A method for controlling an electromagnetic clutch for a vehicle, comprising: correcting the target meat rotation speed. 2. The method for controlling an electromagnetic clutch for a vehicle according to claim 1, wherein the target meat rotation speed is corrected in accordance with a decrease in the output of the engine of the vehicle. 3. The method for controlling an electromagnetic clutch for a vehicle according to claim 1, wherein the target meat rotation speed is corrected according to a change in running resistance of the vehicle.