JPS61206829A - Method for controlling magnetic powder type electromagnetic clutch - Google Patents

Abstract

PURPOSE:To obtain desired transmission torque by newly determining exciting current corresponding to a desired transmission torque from transmission characteristic previously obtained, on a history of the exciting current and the transmission torque. CONSTITUTION:With regard to an exciting current to an electromagnetic clutch, the exciting current of this time is obtained in step 4 on a curve L based on the control current and transmission torque obtained previously and transmission torque obtained this time. And exciting current which is not determined definitely by the transmission torque is determined based on the history of the exciting current or transmission torque up to the time. Then, transmission torque of the electromagnetic clutch is controlled in high accuracy in the process of its engagement.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a control method for a magnetic particle type electromagnetic clutch, and particularly to a technique for increasing control accuracy.

Conventional technology The transmission torque of a magnetic particle type electromagnetic clutch is changed according to the excitation current supplied to it, so if a magnetic particle type electromagnetic clutch is used between the driving side rotating body and the driven side rotating body, the rotation of those rotating bodies can be smoothed. It can be connected to For example, in a vehicle, a magnetic particle type electromagnetic clutch is inserted between the engine crankshaft and the input shaft of the transmission, and the magnetic particle type electromagnetic tarlatch is used to ensure optimal drivability and fuel consumption efficiency when starting the vehicle. The supplied excitation current is controlled by a microcomputer or the like.

Problems to be Solved by the Invention However, in the conventional method of controlling a magnetic particle type electromagnetic clutch, it is assumed that the transmission torque is uniquely determined according to the excitation current supplied to the magnetic particle type electromagnetic clutch. It is difficult to control with high precision, and for example, in half-clutch control of a vehicle, it has been a cause of variations in drivability and fuel consumption efficiency. In other words, in general, there is hysteresis in the transmission characteristics of magnetic particle electromagnetic clutches expressed by the relationship between transmitted torque and excitation current, so the transmitted torque is not determined uniquely by the excitation current, but is influenced by the past history. Although this is unavoidable, in the conventional case, for example, a certain relationship was used that approximated the characteristics when the excitation current increased and decreased, such as the characteristic showing the average of hysteresis.

Means for Solving the Problems The present invention has been made against the background of the above-mentioned circumstances, and its gist is that when sequentially determining the excitation current to obtain the desired transmission torque, The object of the present invention is to newly determine an excitation current corresponding to the desired transmission torque based on the past history of the excitation current or transmission torque from the determined transmission characteristics.

Operation and Effect of the Invention With this method, a new excitation current is determined from the transmission characteristics determined in advance based on the history of the excitation current or transmission torque, so that the excitation current is applied to the magnetic particle type electromagnetic clutch. Once supplied, the desired transmitted torque is precisely obtained. Therefore, the transmission torque of the magnetic particle type electromagnetic clutch can be controlled with high precision during the engagement process, and suitable drivability and fuel consumption efficiency can be obtained without variation in, for example, half-clutch control of a vehicle.

The transfer characteristic includes an ascending line indicating a change in the transfer torque when the excitation current increases from a minimum value, and a descending line indicating a change in the transfer torque when the a-magnetic current decreases from a maximum value. If the transmitted torque decreases while increasing along the ascending line or increases while decreasing along the descending line, preferably a line connecting the ascending line and the descending line. The excitation current is determined based on. The line is a straight line or a curved line that approximates the actual hysteresis curve.

Embodiment FIG. 1 shows a vehicle control device to which the present invention is applied. A magnetic particle type electromagnetic clutch 18 is inserted between the crankshaft 12 of the engine 10 and the input shaft 16 of the transmission 14, and allows or blocks power transmission from the crankshaft 12 to the input shaft 16, and also allows the vehicle to start. At times, the crankshaft 12 and the input shaft 16 are rotated relative to each other while power is transmitted under half-clutch control.

The magnetic particle type electromagnetic clutch 18 includes a drive side rotating body 24 connected to the crankshaft 12, a rotor 28 connected to the input shaft 16, and a magnetic powder type electromagnetic clutch interposed between the drive side rotating body 24 and the rotor 28. The excitation coil 30 adjusts the transmission torque of the magnetic particle type electromagnetic clutch 18 by magnetically changing the coupling state of the magnetic particle type electromagnetic clutch 18. For example, as shown in detail in FIG.
It consists of an outer circumferential member 32 fixed to and an annular yoke 34 fixed inside the outer circumferential member 32, and an annular excitation coil 30 is embedded within the yoke 34.

An excitation current is supplied to the excitation coil 30 from a power supply brush (not shown) via a slip ring 36 that rotates together with the yoke 34. A rotor 28 is rotatably supported inside the yoke 34 by a first labyrinth member 40 via a bearing 38. This first labyrinth member 40 is fixed to one end surface 4 of the yoke 34, and an annular projection 42 for sealing magnetic particles is fixed thereto. This annular projection 42 and the yoke 34
A substantially sealed annular space is formed by the second labyrinth member 44 provided on the other end surface of the magnetic powder, thereby preventing leakage of magnetic particles. Therefore, magnetic powder type electromagnetic clutch 1
8, when a magnetic field is formed between the rotor 28 and the yoke 34 according to the excitation current flowing through the excitation coil 30, magnetic particles fill the gap between the inner peripheral surface of the yoke 34 and the outer peripheral surface of the rotor 28. The rotational force of the crankshaft 12 is transmitted to the input shaft 16 according to the transmission characteristics shown in FIG. This input shaft 16 is connected to the hub 46 of the rotor 28 at the shaft end.
and are connected by spline fitting.

Returning to FIG. 1, a throttle sensor 50 is provided in a throttle valve (not shown) provided in the intake pipe of the engine 10, and a throttle signal Sθ representing the throttle valve opening degree θ is sent from the throttle sensor 50 to the controller 52. The signal is supplied to the A/D converter 54 of. Further, an ignition signal SI corresponding to an ignition pulse for the engine 10 is supplied from an igniter 56 attached to the engine 10 to an I/F circuit 58 in the controller 52. I
The /F circuit 58 sets the ignition period T5, based on the ignition signal Sl.
Output.

The controller 52 is composed of a so-called microcomputer, and includes a CPU 64 . ROM66, RAM68. A D/A converter 70 is provided. The CPU 64 processes the input signal using the temporary storage function of the RAM 68 according to a program stored in advance in the ROM 66, and outputs the control voltage Vcl to the amplifier 72 via the D/A converter 70. amplifier 72
By amplifying the input signal with a constant amplification factor, an excitation voltage corresponding to the control voltage Vcl is applied to the excitation coil 30, and an excitation current Icl corresponding to the winding resistance of the excitation coil 30 is applied to the excitation coil 30. be swept away. Since the winding resistance is approximately constant, the excitation coil 30 is supplied with an excitation current Icl corresponding to the control voltage Vcl. Note that instead of the amplifier 72, a constant current device may be provided that outputs an excitation current of a magnitude corresponding to the control voltage Vcl by current feedback regardless of changes in winding resistance.

The operation of this embodiment will be explained below according to the flowchart of FIG.

First, step S1 is executed, and the throttle valve opening θ
The engine rotational speed No. is read based on the throttle signal Sθ and the ignition signal SI, and step S2 is executed to calculate the transmission torque Tcl.

In step S2, for example, a control equation shown in equation (1) is used.

T<:1=Kcl(θ)・(Ne −Nidl)・
-1f) The control coefficient Kcl in equation (1) is a function of the throttle valve opening θ as shown in the relationship shown in FIG. 5, for example, and is determined based on the throttle valve opening θ. Also, (1)
N idl in the equation is the rotational speed of the engine 10 at idle, and is determined in advance by a step not shown.

In step S3, the control coefficient C is determined from the previously determined equation (2). This control coefficient is a quantity that determines the slope of the curve described later, and C=fc(TCl)...
(2) For the relationship of equation (2), for example, the one shown in FIG. 6 is used. Then, when the subsequent step S4 is executed, the excitation current Icl is calculated according to equation (3).

・ ・ ・ ・(3) However, C-', I cl-', and Te1-' are the control coefficient, exciting current, and transmission torque in the previous control cycle, respectively.

That is, the relational expression shown in equation (3) shows the curve shown in FIG. 7, and in step S4, based on the control current and transmission torque determined last time and the transmission torque determined this time, Current excitation current 1cl on the curve
This is what we seek.

In step S5, the maximum current ICLmx and the minimum current I Crate are determined from the transmission torque determined in step S2 from the function ft(Tel) representing the rising line 76 and the function fz(, Te1) representing the descending line 78 in FIG. Each is calculated based on Tel. The rising line 76 and the falling line 78 are lines that basically constitute the transfer characteristic of FIG. 7 having hysteresis, and the rising line 76 represents the change in the transmitted torque Tel when the exciting current Icl increases from the minimum value. A descending line 78 shows the change in the transmitted torque Tel when the excitation current decreases from the maximum value.

Then, in steps S6 and S8, step S
It is determined whether the excitation current 1cl obtained in step S5 is larger than the maximum current IC15ax obtained in step S5, and whether it is smaller than the minimum current ICLi+s. In step S6, if it is determined that the excitation current Icl obtained in step S4 is not larger than the maximum current Ic1, □, the next step S8 is directly executed, but if it is determined that it is larger, step S4 By setting the excitation current Icl obtained in the above as the maximum current ICLHx, an increase beyond that value is restricted. Also, step S
In step 8, if it is determined that the excitation current rcl obtained in step S4 is not smaller than the minimum current I C15in, the next step SIO is directly executed. The obtained excitation current 1cl is updated to the minimum current ICLzn and the minimum current I
Decrease below C1mtn is suppressed.

Step S10 is then executed, and the control voltage Vcl is output from the controller 52 to the amplifier 72 so that the excitation current 1 cl determined as described above is supplied to the excitation coil 30 of the magnetic particle electromagnetic clutch 18.

Therefore, by repeatedly performing the above steps, the exciting current Ic is
l is determined sequentially. For example, when the transmission torque Tel determined in step S2 increases from A to B in FIG. 7 and then returns to A, the exciting current Icl is initially a
A of the transmitted torque Tel is determined to be the value corresponding to the point.
The excitation current 1cl is determined along the curve passing through point a, and when the state is lower than the point where the curve passing through point a intersects with the ascending line 76, the excitation current 1cl increases from
cl will be defined along the rising line 76.

Then, when the transmitted torque Tel decreases from the B value, the exciting current 1cl is determined along the curve passing through point C, and is higher than the intersection point d of the curve passing through point C and the descending line 78. When the rotating state is reached, the excitation current Icl is determined along the descending line 78. That is, the excitation current 1cl is at point a and point b.

It is determined from the minor hysteresis loop connecting points C and d.

As described above, according to this embodiment, the excitation current ■cl for obtaining the non-transfer torque Tel, which is sequentially determined in step S2 for half-clutch control of the vehicle, takes into account the hysteresis of the transfer characteristic shown in FIG. Determined by That is, since the excitation current Tel, which is not uniquely determined by the transmission torque Tel, is determined based on the past history of the excitation current Icl or the transmission torque Tel, the actual transmission torque of the magnetic particle electromagnetic clutch 18 can be controlled with high precision. be done. As a result, in half-clutch control when starting the vehicle, suitable drivability and fuel consumption efficiency can be stably obtained without variation.

Incidentally, in the conventional case, for example, the excitation current Icl was determined from a line representing the average value of the rising line 76 and the falling line 78 shown in FIG.
Variations associated with historical phenomena (historical phenomena) were unavoidable.

Next, another application example of the present invention will be explained. 'In the following description, the same parts as those in the previous example are given the same reference numerals and the description will be omitted.

In FIG. 8, in step SA4, excitation current 1cl is calculated based on equation (4).

Ic1=C・(Tcl−Tcl”)+Icl”・
- In Equation 141 (4), Tel'' and Icl'' respectively indicate the latest transmission torque and excitation current values for which the excitation current Icl has already been determined on the ascending line 76 or descending line 78. For example, if the exciting current Icl is to be determined between the line a and b in FIG.
Tel" and Icl" indicate the transmitted torque and excitation current at point C when it is to be determined between points d and d. Note that steps SAT and SA9 not only limit the excitation current 1cl between the upper limit value 1clamx and the lower limit value Iclata, but also update Icl'' and Tel'' to the latest values. It is something.

According to this embodiment, when starting from the descending line 78 and returning to the descending line 78 as shown in line C in FIG. 9, or starting from the ascending line 76 and returning to the descending line 78 as shown in line D When returning to line 76, there is an advantage that it is possible to reliably return to the starting point. Incidentally, the fourth
In the embodiment shown in the figure, formula (3) is used to determine the excitation current, and the control coefficient C of formula (3) is determined according to a function that increases as the transmitted torque increases, as shown in Figure 6. Therefore, as shown in Figure 10,
When the excitation current Icl fluctuates with a constant amplitude, the corresponding transmission torque Tel sometimes shifts slightly.

Further, according to this embodiment, as shown in line E-F in FIG. The arrival point f may deviate from the starting point e.

Such a case can be almost eliminated by changing the control coefficient C, which is related to the slope of the line, between the case of starting from the descending line 78 and the case of starting from the ascending line 76. The embodiment described below is for that purpose.

In FIG. 11, the content of flag F, which indicates that the vehicle is on the descending line 78 or on a line departing from it toward the ascending line 76, is determined.

If the content of flag F is "1", descending line 7
8 side, step 5B31 is executed and the control coefficient 01 is determined by the predetermined function (Ct" f c'(Te
l)), step 5B41 is executed, and excitation current 1cl is calculated from equation (4) in the same way as step SA4 described above. Meanwhile, step 5B20
If it is determined that the content of the flag F is not "1", it is on the rising line 76 side, so step 5B32
is executed, and the control coefficient 02 is calculated using the predetermined function (C
z=fc! (Tel)), and step 5B42 is executed to calculate the excitation current 1cl from equation (4) in the same way as step SA4 described above. According to this embodiment, when starting from the ascending line 76, , a different control coefficient 01 or C2 is obtained according to a different function than when starting from the descending line 78. For example, when starting from the ascending line 76, reaching the descending line 78, and returning to the ascending line 76, The point of arrival at line 76 is made approximately coincident with the point of departure from ascending line 76. The above function is thus defined.

In addition, step SB? and SB9 not only limits the excitation current 1cl between the maximum current ICLax and the minimum current I C15in as in steps SA7 and SA9 described above, but also updates Tel" and Icl".
Rewrite the contents of flag F. That is, step SB
In step SB9, the content of the flag F is set to "0" because the ascending line 76 has been reached, and in step SB9, the content of the flag F is set to "0" since the descending line 78 has been reached.
The content of is set to "1".

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

For example, in the above-described embodiment, the control coefficient C is determined in relation to the transmission torque Tc1, as shown in the relationship shown in FIG. 6, but even if it is a constant value, a certain effect can be obtained. . In such a case, for example, line L in FIG. 7 becomes a straight line.

In addition, in the above-mentioned embodiment, the control coefficient C1 control coefficient Kc
1. Although the excitation current Icl is determined based on a predetermined function, it may also be determined from a data map corresponding to the function.

In addition, as shown in FIG. 12, step 5 of FIG.
5C41 and SC42 are provided in place of B31.5B32, 5B41, and 5B42, and thereby the excitation current 1
It is also possible to obtain cl.

In step SC41, the excitation current 1cl is determined based on the transmission torque Tel obtained in the current control cycle from the function or data map when starting from the descending line 78 side and the Tcl obtained in the previous cycle. On the other hand, in step 5C42, the transmission torque Tel obtained in the current cycle and T obtained in the previous cycle are calculated from the function or data map when starting from the ascending line 76 side.
cl", the excitation current 1cl is determined.

That is, according to this embodiment, the excitation current 1cl is determined according to the history of the transmitted torque up to that point.

The above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a control device for a magnetic particle type electromagnetic clutch for a vehicle to which the present invention is applied. FIG. 2 is a sectional view illustrating the structure of the magnetic particle type electromagnetic clutch shown in FIG. 1. FIG. 3 is a diagram showing the transmission characteristics of the magnetic particle type electromagnetic clutch shown in FIG. 2. FIG. 4 is a flowchart illustrating the operation of the apparatus of FIG. 1. 5 and 6 are diagrams showing functions used when determining control coefficients in the flowchart of FIG. 4. FIG. 7 is a characteristic diagram used to explain the operation of FIG. 4. FIG. 8 is a diagram corresponding to FIG. 4 for explaining the operation of another application example of the present invention. FIG. 9 is a characteristic diagram used to explain the operation of the embodiment shown in FIG. FIG. 10 is an explanatory diagram showing changes in transmitted torque when the excitation current fluctuates with a constant amplitude in the operation of the embodiment shown in FIG. 4. FIG. 11 is a diagram corresponding to FIG. 4 showing another example of application of the present invention. FIG. 12 is a flowchart illustrating the main part of another general example of the present invention. 18: Magnetic powder electromagnetic clutch

Claims (2)

[Claims] (1) A control method for a magnetic particle type electromagnetic clutch in which hysteresis exists in the transmission characteristics expressed by the relationship between the excitation current and the transmission torque obtained correspondingly, the excitation current for obtaining a desired transmission torque. A magnetic particle type electromagnetic clutch characterized in that, in sequentially determining, an exciting current corresponding to the desired transmission torque is newly determined based on the history of the exciting current or the transmitted torque from the previously determined transmission characteristics. control method. (2) The transfer characteristic includes a rising line indicating a change in transmission torque when the excitation current increases from a minimum value, and a descending line indicating a change in transmission torque when the excitation current decreases from a maximum value. If the transmitted torque decreases while increasing along the ascending line or increases while decreasing along the descending line, a predetermined 2. The method of controlling a magnetic particle type electromagnetic clutch according to claim 1, wherein the excitation current is determined based on a line.