JPH0617694B2 - Control device for magnetic powder type electromagnetic clutch for vehicle - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control device for a magnetic powder electromagnetic clutch for a vehicle,
In particular, the present invention relates to a control technique for adjusting torque in the engagement process of an electromagnetic clutch.

2. Description of the Related Art There is a magnetic powder type electromagnetic clutch as a kind of clutch inserted in a power transmission path from an engine of a vehicle to driving wheels. Since such a magnetic powder type electromagnetic clutch can transmit a torque having a magnitude corresponding to the exciting current supplied to the exciting coil, it has a feature that it is easily controlled by a control means such as a microcomputer. For example, when the vehicle is started, engagement control is performed in which the electromagnetic clutch is engaged as smoothly as possible while the engagement rotational speed is made as low as possible to enhance fuel consumption efficiency. In such engagement control, in determining the excitation power (voltage or current), in order to smoothly engage the clutch and enhance drivability at the time of starting the vehicle, the engine of Although it is necessary to increase the meat rotation speed, in such a case, the fuel consumption efficiency at the time of starting the vehicle is reduced. On the other hand, if the engine rotation speed at the time of engagement of the electromagnetic clutch is reduced to increase the fuel consumption efficiency, the drivability (acceleration) at the start of the vehicle is impaired, and the engine rotation speed fluctuation ( Pulsation) may occur to impair drivability. Therefore, when the vehicle is started, the meat rotation speed of the engine when the electromagnetic clutch is engaged is uniformly determined at the point where both the drivability and the fuel consumption efficiency when the vehicle is started are satisfied to some extent. Is common.

Problems to be Solved by the Invention However, when the vehicle is actually started, the drivability (acceleration) is more important than the fuel consumption efficiency or the fuel is more important than the drivability depending on the driver's preference or driving conditions. In some cases, the efficiency of consumption is emphasized, but in the conventional electromagnetic clutch control method, the meat rotation speed of the engine is uniformly determined, and thus it was not possible to meet such various requirements. .

Means for Solving the Problems The present invention has been made in view of the above circumstances, and the gist of the present invention is to insert an exciting coil in a power transmission path from an engine of a vehicle to driving wheels. In a magnetic powder type electromagnetic clutch for a vehicle that transmits a torque having a magnitude corresponding to the exciting current supplied to the, by increasing the exciting current of the exciting coil at a predetermined increase rate according to the increase of the rotation speed of the engine. A control device for adjusting the transmission torque in the engagement process of the electromagnetic clutch,
(1) engine rotation speed detection means for detecting the actual rotation speed of the engine, (2) throttle operation amount detection means for detecting the actual throttle operation amount for the engine, (3) pre-commanded command meet A command meat rotation speed reading means for reading the rotation speed, and (4) from the previously determined relationship, the predetermined increase rate is determined based on the command meat rotation speed and the actual throttle operation amount of the engine, and this increase Control means for increasing the exciting current of the exciting coil in accordance with the increase in the actual rotational speed of the engine in accordance with the rate.

In this way, when the above-mentioned predetermined increase rate is determined based on the command meet rotation speed and the actual throttle operation amount, the control means follows the actual increase rate of the engine according to this increase rate. The exciting current of the exciting coil is increased in accordance with the increase in speed. That is, at the same throttle opening, the meat rotation speed is determined by the above-mentioned increase rate, and by adjusting the increase rate based on the commanded meet rotation speed, the engine rotation speed is changed when the magnetic powder electromagnetic clutch is engaged. The desired commanded rotation speed can be maintained. Further, although the meat rotation speed changes depending on the throttle operation amount, by adjusting the increase rate based on the throttle operation amount, the engine rotation speed is maintained at the desired command meat rotation speed regardless of the throttle operation amount. It Therefore, it is possible to engage the magnetic powder type electromagnetic clutch at a meet rotation speed corresponding to various requirements that place importance on drivability or fuel consumption efficiency when the vehicle starts, and desired drivability or fuel economy when the vehicle starts. Is obtained.

Here, the meat rotation speed refers to the rotation speed of the engine when the output torque of the engine and the transmission torque of the magnetic powder type electromagnetic clutch match, and in such a case, when the vehicle starts, in other words, the magnetic powder type electromagnetic clutch. The rotational speed of the engine becomes substantially constant when the clutch is engaged.

Embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 2, 10 is an example of a magnetic powder type electromagnetic clutch, in which a flywheel 14 fixed to the shaft end of a crankshaft 12 is an annular yoke 16 as a driving side rotating body.
Is equipped with. At the center of the cross section of the yoke 16,
An annular exciting coil 18 is embedded, and an exciting current is supplied to the exciting coil 18 from a power supply brush (not shown) via a slip ring 20 that rotates together with the yoke 16. A rotor 22, which is a driven-side rotating body, is rotatably supported by a first labyrinth member 26 via a bearing 24 inside the yoke 16. The first labyrinth member 26 is fixed to one end surface of the yoke 16 and is filled with a magnetic force in a gap formed between the inner peripheral surface of the yoke 16 and the outer peripheral surface of the rotor 22. An annular protrusion 28 that seals the magnetic powder 32 is fixed. The second labyrinth member 3 provided on the other end surface of the annular protrusion 28 and the yoke 16.
0 forms a substantially sealed annular space, and the magnetic particles 3
The leakage of 2 is prevented. Electromagnetic clutch 10
In the above, when a magnetic field is formed in accordance with the exciting current passed through the exciting coil 18, the magnetic powder 32 is filled in the gap between the yoke 16 and the rotor 22, and the torque of the crankshaft 12 is increased according to the characteristics shown in FIG. It is transmitted to the output shaft 34. The output shaft 34 is spline-fitted to the hub 36 at its shaft end, and the hub 36 is connected to the rotor 22 via a damper 38 for absorbing an engagement shock. The output torque output from the output shaft 34 is transmitted to the drive wheels of the vehicle through a continuously variable transmission, a stepped transmission, a differential device or the like (not shown).

FIG. 7 shows a main part of a control circuit using the electromagnetic clutch 10 having the above-described structure.
A signal representing the throttle operation amount (opening) θ corresponding to the operation amount of the accelerator pedal is supplied to the A / D converter 46 of the microcomputer (eg, so-called ECU) 44 from the throttle sensor 42 provided in the intake pipe. It In addition, an igniter 48 attached to the engine 40
A signal corresponding to the ignition pulse for the engine 40 is supplied to the I / F circuit 50 of the microcomputer 44. That is, in this embodiment, the throttle sensor 4
2 and the A / D converter 46 constitute a throttle operation amount detecting means, and the igniter 48 and the I / F circuit 50 constitute an engine rotational speed detecting means. The microcomputer 44 includes a CPU 52, a ROM 54, and a RAM
Including 56, the CPU 52 executes signal processing according to 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 amplifies the input signal with a constant amplification factor to control the voltage V
An exciting voltage V having a magnitude corresponding to cl is applied to the exciting coil 18, and an exciting current Icl corresponding to the winding resistance R is applied to the exciting coil 18. The I / F circuit 50 is for converting the number of ignition pulses per unit time, in other words, the rotational speed of the crankshaft 12.
Further, a meet rotation speed setting device 62 is connected to the microcomputer 44, and when any one of a plurality of types of driving patterns such as "power", "normal", "economy" is selected according to the driver's preference, A signal representing the desired commanded meat rotation speed N'that obtains the drivability or fuel consumption efficiency corresponding to the operation pattern is output from the meat rotation speed setting unit 62 to the microcomputer 44.
To be supplied to. In the meat rotation speed setting device 62, a plurality of types of designated meat rotation speeds N'corresponding to operation patterns are stored in advance.

Here, the ROM 54 stores the relationship obtained in advance according to the steps shown in FIG. That is, as shown in FIG. 5, with the change width of the throttle operation amount (opening) θ being constant, the change of the gain K when controlling the transmission torque of the electromagnetic clutch 10 using the general control equation (1). The meat rotation speed Nm is measured.

V = K (N-Nidl) (1) where V is the excitation voltage, K is the gain, N is the engine speed, and Nidl is the engine idle speed.

The graph shows the actual measurement value of the meat rotation speed Nm in the electromagnetic clutch 10 when the operation amount of the throttle opening θ is set to 30% and the gain K in this case is changed in a plurality of steps. The meat rotation speed Nm is the engine rotation speed when the output torque of the engine 40 and the transmission torque of the magnetic powder type electromagnetic clutch 10 match, and the engine rotation speed N becomes constant when the electromagnetic clutch 10 is engaged. It is a part. For example, as shown in FIG.
When it is 0.08, the meat rotation speed Nm is about 1500 rpm, and when the gain K is 0.2, the meat rotation speed Nm is 1.
It will be about 000 rpm.

Next, the throttle operation amount θ is changed to a value within the range of 10 to 70%, for example, 10, 20, 40, 50, 70%, and the value of the meat rotation speed Nm with respect to the gain K is measured,
The function K = f (Nm, θ) (2) of the gain K, which has the meat rotation speed Nm and the throttle opening θ as variables, is obtained. Gain K within an appropriate range of throttle operation amount θ
A constant relationship is obtained if is changed. This functional expression is represented by, for example, K = a (θ) · Nm + b (θ) as shown in FIG.

Then, the control equation (3) obtained by substituting the function (2) obtained by actual measurement into the general control equation (1) as described above is stored in advance in the ROM 54 in the form of a functional equation and / or a data map.

Vcl = f (N ′, θ) × (N−Nidl) (3) This relational expression (3) is the control expression of this embodiment. That is,
When the meat rotation speed Nm is designated, the control voltage Vcl, that is, the excitation voltage V is determined based on the actual throttle operation amount θ and the engine rotation speed N so that the electromagnetic clutch 10 is engaged at the designated rotation speed. Is done. In addition, in equation (3), instead of the meat rotation speed Nm,
A command meet rotation speed N'commanded in the control circuit is used.

The operation of this embodiment will be described below with reference to the flowchart of FIG.

First, step S1 is executed and while the throttle operation amount θ is zero, in other words, while the throttle is closed, the idle rotation speed Nidl of the engine 40 is learned and stored by executing a predetermined algorithm. Next, step S
2 is executed, and it is determined whether or not the throttle operation is performed, in other words, whether or not the throttle operation amount θ is larger than a predetermined small value. When it is determined that the throttle operation has not been performed, the execution of step S1 is repeated. However, when it is determined that the throttle operation has been performed, the vehicle is in a starting state, and therefore the command meet rotation speed reading means. As step S
3 and below are executed.

In step S3, the actual throttle operation amount θ is read, and the commanded meet rotation speed N ′ is read in accordance with the signal from the meet rotation speed setter 62.
This command meet rotation speed N'is a value corresponding to a desired driving pattern selected by the driver, for example. Then
Step S4 is executed, the gain K is first determined based on the throttle operation amount θ and the command meet rotation speed N ′ read in step S3 from the relational expression (2), and step S5 is executed to determine the actual value. The engine speed N is read. Next, step S6 is executed, and the gain K determined in step S4, the engine speed N read in step S5, and step S1 are calculated from the relationship shown in the equation (3) obtained in advance.
The control voltage Vcl is determined based on the idle rotation speed Nidl stored in step S7, and is output in step S7. That is, steps S4, S6 and S7
Constitutes the control means. Then, by repeating the above steps S3 to S7,
The exciting voltage V applied to the exciting coil 18 of the magnetic powder type electromagnetic clutch 10, that is, the exciting current Icl is controlled.

As described above, the gain K, the throttle operation amount θ, and the command meet rotation speed N ′, that is, the meet rotation speed Nm, have a constant relationship as shown in the equation (2), and the throttle operation amount θ may be constant. For example, command meet rotation speed N '
Is increased, the gain K is decreased, and conversely, the gain K is increased when the command meet rotational speed N'is decreased. Therefore, according to the control of the control equation of the present embodiment obtained by substituting the equation (2) into the general control equation (1), the throttle operation can be performed by determining the command meet rotation speed N '. Regardless of the value of the amount θ, in other words, the accelerator operation amount, the meet rotation speed Nm of the electromagnetic clutch 10 is held at the command meet rotation speed N ′. Therefore, for example, drivability or fuel consumption efficiency based on the meat rotation speed N'corresponding to the driving pattern selected by the driver can be obtained.

In the above-described embodiment, the command meet rotation speed N'is configured to be output from the meet rotation speed setter 62 corresponding to the driving pattern selected by the driver. It may be configured such that it is sequentially automatically determined and output from the command meet rotation speed setting device 62, and the command meet rotation speed N ′ is read in step S3.

Further, although the relational expression shown in the formula (3) is used in the above-mentioned embodiment, if the formula (2) considers a constant amplification factor of the amplifier 60, the left side is the excitation voltage V. It is also possible to set the exciting current Icl on the left side in consideration of the specific resistance R of the exciting coil 18. In the latter case, the amplifier 60 is replaced with a constant current control circuit for forcibly flowing the exciting current Icl corresponding to the control voltage Vcl, so that high accuracy can be achieved regardless of the temperature change of the winding resistance of the exciting coil 18. It becomes possible to control the torque.

The above description is merely one embodiment 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 flow chart for explaining the operation of one embodiment of the present invention. FIG. 2 is a front sectional view showing an example of a magnetic powder type electromagnetic clutch which is a control target of the present invention. FIG. 3 is a diagram showing the characteristics of the magnetic powder type electromagnetic clutch of FIG. Fourth
The figure is a diagram showing steps for previously obtaining the relationship used in the embodiment of FIG. FIG. 5 and FIG. 6 are diagrams showing examples of actual measurement values at the respective steps of FIG.
FIG. 7 is a block diagram showing the configuration of the control circuit of the embodiment shown in FIG. 10: Magnetic powder type electromagnetic clutch 18: Excitation coil, 40: Engine 42: Throttle sensor (throttle operation amount detection means) 46: A / D converter (throttle operation amount detection means) 48: Igniter (engine rotation speed detection means) 50 : I / F circuit (engine rotation speed detection means) Step S3: command meet rotation speed reading means Steps S4, S6, S7: control means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Shigematsu 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Corporation (56) Reference JP-A-59-187117 (JP, A) JP-A-57-87722 (JP, A) JP 57-138429 (JP, A)

Claims (1)

[Claims] 1. A magnetic powder type electromagnetic clutch for a vehicle, which is inserted in a power transmission path from an engine of a vehicle to a drive wheel and transmits a torque having a magnitude corresponding to an exciting current supplied to an exciting coil, wherein A control device for adjusting the transmission torque in the engagement process of the electromagnetic clutch by increasing the exciting current of the exciting coil at a predetermined increase rate according to the increase of the rotation speed, wherein the actual rotation speed of the engine An engine rotation speed detecting means for detecting, a throttle operation amount detecting means for detecting an actual throttle operation amount for the engine, a command meat rotation speed reading means for reading a pre-commanded command meat rotation speed, and a predetermined From the relationship, the predetermined increase rate is determined based on the commanded meat rotation speed and the actual throttle operation amount. And a control means for increasing the exciting current of the exciting coil in accordance with the increase in the actual rotation speed of the engine according to the increasing rate.