JPS61206830A - Method of controlling magnetic powder type electromagnetic clutch for vehicle - Google Patents

Abstract

PURPOSE:To make objective meet rotating speed a value reflected by will of a driver by determining the objective meet rotating speed based on at least one of required output of a vehicle and changing speed of the required output from the relation previously obtained. CONSTITUTION:An objective meet rotating speed of an engine is gradually determined in an objective meet rotating speed setting unit. And the objective meet rotating speed is gradually determined based on a throttle valve opening thetaand its changing speed theta'. Therefore, when the throttle valve opening theta and its changing speed theta' are large, the objective meet rotating speed is made larger and the opening theta and changing speed theta' are small, the objective meet rotating speed is made smaller relatively. Then, the objective meet rotating speed is determined to a value reflected by the will of a driver.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for controlling a magnetic particle type electromagnetic clutch for a vehicle, and more particularly to a control technique for adjusting torque during the engagement process of an electromagnetic clutch.

Prior Art - A magnetic particle type electromagnetic clutch is a type of clutch inserted in the power transmission path from the engine to the drive wheels of a vehicle. Since such a magnetic particle type electromagnetic clutch can obtain a transmission torque of a magnitude corresponding to the excitation current supplied to its excitation coil, smooth engagement similar to that of a fluid clutch can be achieved by using control means such as a microcomputer. This is achieved automatically without the need for
Half-clutch control of such a magnetic particle electromagnetic clutch, which can achieve fuel efficiency equivalent to that of a friction clutch, smoothes engagement and improves drivability when starting the vehicle, and also improves drivability on the input side when engaged. In order to suppress the rotational speed and increase fuel consumption efficiency, various control equations such as those shown in the following equations (11 and (21) have been devised.

Tc1=K(θ, N”)(N e −N1dl)
(11) where Tcl is the transmission torque, K is the feedback gain, θ is the throttle valve opening, N'' is the target rotational speed, Ne is the engine rotational speed, and N idl is the idle rotational speed.

Tcl = Te(θ+N e) +k + (N
eN”)+kJ(NeN”)dt...
12) However, Te is the engine output torque, kl is the proportional control constant, and k2 is the integral control constant.

If the above control formula (1) is used, patent application No. 59-13349
As described in detail in No. 1, a desired meeting rotation speed can be obtained for any throttle valve opening within a predetermined range. In other words, the electromagnetic clutch operates in a half-clutch state so that a constant target rotational speed N11 is maintained regardless of the throttle valve opening. Control equation (2) is provided with a term corresponding to the instantaneous value Te of the engine output torque in order to improve transient response, and a second term is provided as a feedback control term for the meat rotation speed. A third term is provided, and feedback control is performed so that the target rotational speed and the actual engine rotational speed Ne are approximated. That is, even in this case, the predetermined target rotational speed N8 can be obtained in the half-clutch control regardless of the throttle valve opening.

Therefore, if the control formulas (11, 21, etc.) are used, suitable half-clutch control can be obtained regardless of the throttle valve opening degree.

Problems to be Solved by the Invention However, in such conventional control methods, ideal half-clutch control can be achieved by setting the target rotational speed to a constant value that provides both drivability and fuel consumption efficiency. Although this was achieved, there was still room for improvement. In other words, since a constant rotational speed is obtained regardless of the throttle valve opening, the starting acceleration may not be sufficient for drivers who value drivability, and the fuel consumption efficiency may be insufficient for drivers who value economy. In some cases, this is not sufficient, and there is an inconvenience that drivability that reflects the driver's intention cannot necessarily be obtained.

Means for Solving the Problems The present invention has been made against the background of the above-mentioned circumstances, and its gist is to reduce the engine rotational speed to a target level when starting a vehicle equipped with a magnetic particle type electromagnetic clutch. When controlling the excitation current to achieve the rotational speed, the target rotational speed is determined based on at least one of the required output of the vehicle and the rate of change of the required output from a predetermined relationship.

Operation and Effect of the Invention In this way, the target rotational speed is determined based on at least one of the required output of the vehicle, which represents the driver's intention, and the rate of change of the required output. is determined to a value that reflects the driver's intention. Therefore, in half-clutch control of a magnetic particle type electromagnetic clutch,
It is possible to obtain suitable drivability or fuel consumption efficiency that responds to the driver's intentions.

The target rotation speed is corrected in response to a driving performance selection switch that selects the driving performance of the vehicle, such as economical driving or power driving. In this way, the magnetic particle type electromagnetic clutch is controlled so that the running performance selected by the running performance selection switch is obtained even when the vehicle starts.

Further, the target meat rotation speed is corrected to increase in accordance with a decrease in engine output. For example, in a cold engine, the output torque is small even at the same rotational speed, so by such an increase correction, the same drivability as in a warm state can be obtained.

Further, the target meeting rotation speed is preferably corrected in accordance with a change in running resistance of the vehicle. The running resistance of a vehicle varies depending on gradient resistance due to the slope of the road surface, acceleration resistance due to vehicle weight, rolling resistance due to road friction coefficient, steering angle, etc., and such changes in running resistance occur even if the engine output is constant. Since the drivability changes depending on the amount of the vehicle, this kind of correction makes it possible to obtain the same suitable drivability as when starting on flat ground, starting with an empty vehicle, starting on a paved road, etc. even if there is a change in running resistance. .

Here, the meet rotation speed refers to a phenomenon in which the input side rotation speed of the magnetic particle type electromagnetic clutch remains at a substantially constant value during half-clutch control of the magnetic particle type electromagnetic clutch, and such a constant value is called the meet rotation speed. It is. Assuming that the input end of the magnetic particle type electromagnetic clutch is directly connected to the engine, the equation of motion of the engine crankshaft is expressed as the following equation (3). In this equation (3), magnetic powder Niden I meat e = Te − Tcl ・・
(3) where I is the moment of inertia of the crankshaft including the flywheel, Qe is the rotational acceleration of the engine, Te is the output torque of the engine, and Tel is the transmission torque of the magnetic particle electromagnetic clutch.

When the magnetic clutch is engaged, the engine rotational speed Ne becomes constant and Me becomes 0, so Te -Tel, and the engine torque determined by the throttle valve opening and the meet rotational speed at that time is transmitted. Therefore, controlling the clutch rotation speed in the half-clutch state is nothing but controlling the transmission torque Tel.

EXAMPLE Hereinafter, an application example of the present invention will be explained in detail based on the drawings.

In FIG. 1, a magnetic particle type electromagnetic clutch 16 is provided between a crankshaft 12 of an engine 10 and an input shaft 14 of a transmission (not shown). As shown in FIG. 2, the magnetic particle type electromagnetic clutch 16
A flywheel 18 fixed to the shaft end is provided on the input side,
The flywheel 18 includes an annular yoke 20.

An annular excitation coil 22 is embedded in the center of the yoke 20, and an excitation current is supplied to the excitation coil 22 from a power supply brush (not shown) via a slip ring 24 that rotates together with the yoke 20. ing. A rotor 26 is rotatably supported inside the yoke 20 by a first labyrinth member 30 via a bearing 28. This first labyrinth member 30 is fixed to one end surface of the yoke 20, and includes magnetic particles to be filled by magnetic force into the gap formed between the inner peripheral surface of the yoke 20 and the outer peripheral surface of the rotor 26. An annular projection 32 for sealing is fixed.

This annular protrusion 32 and a 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. When a magnetic field is formed in accordance with the excitation current flowing through the excitation coil 22, this magnetic powder is filled into the gear between the inner circumferential surface of the yoke 20 and the outer circumferential surface of the rotor 26, and is filled with the crankshaft according to the characteristics shown in FIG. 12 torque is transmitted to the input shaft 14.

The input shaft 14 is spline-fitted to a hub 36 at its shaft end, and the hub 36 is connected to the rotor 26 via a damper 38 for absorbing a locking shock. Note that the driving force transmitted to the input shaft 14 is transmitted to the drive wheels of the vehicle through a transmission, a differential device, etc. configured with 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 that detects the opening degree θ of the throttle valve. The throttle sensor 42 constitutes a required output detection means requested by the driver, and a throttle signal Sθ representing the throttle valve opening θ, which is a reflection of the driver's intention, is sent to the A/D converter 46 in the controller 44. supplied to In addition, from the igniter 48 attached to the engine 10,
Ignition signal S corresponding to an ignition pulse to the engine 10
l is supplied to an I/F circuit 50 within the controller 44. 1/F circuit 50 receives ignition signal SI4 engine rotation speed N
It is converted into an ignition period Ti for calculating e. The controller 44 is composed of a so-called microcomputer called an ECU, and includes a CPU 52. ROM54. RAM56
It is equipped with 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 6o via the D/A converter 58.

The amplifier 60 applies a voltage corresponding to the control voltage Vcl to the excitation coil 22, and an excitation current Icl is caused to flow through the excitation coil 22. This exciting current Icl has a value corresponding to the control voltage Vcl since the winding resistance of the exciting coil 22 is approximately constant. However, in place of the amplifier 6o, a constant current circuit may be provided that causes the excitation current 1cl corresponding to the control voltage Vcl to flow through current feedback regardless of changes in the impedance of the excitation coil 22.

A target meeting rotation speed setter 62 is connected to the data bus line of the controller 44. The target meet rotation speed setting device 62 includes a running performance selection switch 6.
4. Engine temperature sensor 66, steering wheel angle sensor 6
8. Output signals from a road slope sensor 70, a vehicle weight sensor 72, and a road friction sensor 74 are supplied.

The driving performance selection switch 64 is configured to switch between economical driving, normal driving, power driving, and the like by operating an operating body (not shown), and outputs a signal representing the selected driving performance. The engine temperature sensor 66 detects the temperature of the engine 1o, for example, the temperature of its cooling water.
It outputs a signal representing the temperature. The steering wheel turning angle sensor 68 detects the turning angle of the steering wheel of the vehicle, and outputs a signal representing the steering wheel turning angle. The road surface slope sensor 70 detects the slope of the road surface on which the vehicle is located, and outputs a signal representing the slope. The vehicle weight sensor 72 is provided, for example, in the suspension of a vehicle to detect the loaded weight of the vehicle, and outputs a signal representing the weight. The road surface friction sensor 74 is a paved road,
Detects the friction coefficient of road surfaces such as gravel roads, snowy roads, and rainy roads,
A signal representing the friction coefficient is output. The target meat rotation speed setting device 62 is composed of a so-called CPU,
The supplied signal is processed according to a program stored in advance in the ROM 54, and a target meat rotation speed N'' is determined.

The operation of this embodiment will be explained below.

First, step S1 in FIG. 4 is executed, and the engine 10
The idle rotational speed N idl of is learned and stored by executing a predetermined algorithm. Next, step S2
is executed, and the throttle signal Sθ determines whether or not the accelerator is being operated, in other words, whether or not the throttle valve opening θ already read in a step (not shown) is larger than a predetermined small value. be judged based on

When it is determined that the accelerator is not operated, step S3 is executed and the transmission torque Tel to be controlled is
Set to zero. However, if it is determined that the accelerator is operated, step S4 is executed and the target meat rotation speed N'' is read. This target meat rotation speed N11 is sequentially determined by the target meat rotation speed setter 62. ing.

In the target meat rotation speed setter 62, for example, a target meat rotation speed determination routine shown in FIG. 5 is repeatedly executed. That is, in step SWI, the throttle valve opening θ is read based on the throttle signal Sθ, and in step SW2, it is determined whether the content of the flag is "1". This flag F indicates that the rate of change δ of the throttle valve opening is calculated in one start operation of the vehicle, and is reset each time one start operation is completed by a step (not shown). Normally, immediately after the start operation, the throttle valve opening change rate δ has not been 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 contents of the counter (2), and in step SW4, it is determined whether the contents of the counter I have reached a predetermined constant value α. This α is, for example, 100 m□.

This corresponds to the time span for calculating the throttle valve opening change rate δ in one start operation of the vehicle. Immediately after the start operation, the contents of the counter (2) do not reach α, so step SW5 is executed and the transmission torque Tel to be controlled is set to "0". However, when the contents of the counter ■ reach α, step SW6 is executed, and from the throttle valve opening θ at that time and the elapsed time up to that time (time span approximately 100ff1., e corresponding to α), The throttle valve opening change rate is calculated and stored, and the flag F is set to r.
It is set to lJ.

In the following step SW7, a target rotational speed N8 is determined from a predetermined relationship between the current throttle valve opening θ and the throttle valve opening change rate δ determined in step SW6. FIG. 6 shows an example of the predetermined relationship used in step SW7, which is stored in advance in the ROM 54 in the form of a data map.

Between the data in the data map, the target rotational speed N11 is determined as appropriate using means such as linear interpolation.

Note that the relationship shown in FIG.
54, and the target meat rotation speed N'' may be calculated using the functional expression.

In step SW8, each correction value is determined. Correction value ΔN1 corresponding to running performance. For example, based on the predetermined relationship shown in FIG.
is determined according to the switching state of As a result, when switching to power driving, the correction value ΔN3. is increased, so the starting acceleration is greatly improved. On the other hand, when the driving performance selection switch 64 is switched to economical driving, the correction value ΔN''s is made small, and a highly economical starting driving is obtained. Correction value ΔN” corresponding to water temperature
t is determined, for example, from a predetermined relationship shown in FIG. This increases the correction value ΔN'' when sufficient output cannot be obtained when the vehicle is cold, and maintains the same drivability upon starting as when the vehicle is warm.

The correction value ΔN"h corresponding to the steering angle is determined from the predetermined relationship shown in FIG. This is made larger so that the engine lO can be prevented from stopping even when the steering wheel is turned all the way to start the vehicle. Correction value Δ corresponding to road slope
N”r is the road surface slope (ja
As n θ) increases in the positive direction, it increases in the positive direction, and conversely, as it increases in the negative direction, the value becomes a larger negative value. As a result, the same necessary and sufficient engine output as on a flat road can be obtained even when the running resistance changes due to the road surface slope, and suitable drivability is ensured regardless of the road surface slope. The correction value ΔN'o corresponding to the vehicle weight is increased as the vehicle weight increases based on the relationship shown in FIG. If it is predicted that the vehicle weight will increase and the start acceleration performance will decrease, the correction value ΔN38 will be increased.
Drivability at the time of starting is ensured in the same way as when the vehicle is empty. moreover,
The correction value ΔNIIIJ corresponding to the road surface frictional resistance is obtained, for example, from a predetermined relationship shown in FIG. 12. 1st
In the relationship shown in Figure 2, the smaller the road surface friction coefficient, the more negative the correction value ΔN11s becomes. Therefore, on road surfaces with a small friction coefficient, such as snowy roads, gravel roads, wet roads due to rain, etc., the transmitted torque decreases. It is made as small as possible to prevent slipping when the vehicle starts. At this time, the target meeting rotation speed N8 is made smaller as the road surface friction coefficient becomes smaller, but this lower limit value is regulated by the idle rotation speed N1dl.

In step SW9, '' is determined as the total correction value Δ according to the following equation (4).

ΔKI′=(ΔN8.+ΔN”t +ΔNm.

+ΔN1r+ΔN', +ΔN”s)+δ・・・・・・
- (4) However, δ is the output torque T e − of the engine 10.

It is a function of the target rotational speed N3, the throttle valve opening θ, the desired transmission torque Tel, a constant, etc., and is a negative or positive value.

Then, step 5WIO is executed and the total correction value Δ determined in step SW9 of the current cycle is added to the target meat rotation speed N'' determined in the previous cycle.
By adding N1, the target meat rotation speed N1
is updated. And the above steps SWI, SW2
．． By repeating SW7 to SW5WIO, the target meat rotation speed N'' is sequentially determined.

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

By repeating the above steps, the transmission torque of the magnetic particle electromagnetic clutch 16 is sequentially controlled.

As described above, according to this embodiment, the magnetic particle type electromagnetic clutch 1
6, the excitation current to the excitation coil 22 is controlled so as to obtain the target rotational speed N1, so that the drivability and economy when starting the vehicle are improved without requiring any skill. Furthermore, since the target rotational speed Nl' is sequentially determined based on the throttle valve opening θ and its rate of change δ, starting characteristics that reflect the driver's intention can be obtained. For example, when the throttle valve opening θ and its rate of change δ are large, the target rotational speed N'' is increased accordingly, so that suitable starting acceleration can be obtained, while the throttle valve opening θ and the speed of change δ are large. When the rate of change δ is relatively small, the target rotational speed N8 is made relatively small, and the economy at the time of starting is improved.

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

For example, in the above embodiment, the control equation for determining the transmission torque Td may be the one shown in equation (2) above, and in such a case, steps S4 to S7 in FIG. 4 may be replaced with steps S4 to S7 in FIG. SS4 to SS7 are preferably used.

That is, in step S84, the actual engine rotational speed Ne is read, and step S84 is read in.
At step 35, the actual engine torque Te is calculated based on the throttle valve opening θ and the engine rotational speed Ne from a predetermined relationship. Then, in step SS6, the target meat rotation speed Nl' determined by the target meat rotation speed setter 62 is read, and in step SS7
Then, the transmission torque Tel to be controlled is calculated based on the actual engine rotational speed Ne and the target/meet rotational speed N'' from the control equation shown in equation (2) above.

In addition, in the above-mentioned embodiment, the target meat rotation speed N
* was determined by adding 8 to the total correction value Δ to the basic value obtained from the relationship shown in Figure 6, but a certain effect can be obtained even without such correction.
The total correction value ΔN7 includes a correction value ΔN11 corresponding to the operation position of the driving quality selection switch 64, a correction value ΔNIIt corresponding to the engine water temperature, and a correction value Δ corresponding to the steering angle.
N1h, a correction value ΔN"r corresponding to the road surface gradient, a correction value ΔN"8 corresponding to the vehicle weight, a correction value ΔN" corresponding to the road surface friction coefficient, using means such as weighting from one or more of the following: It may be determined.

Further, in the above-mentioned embodiment, the target meat rotation speed N8
is determined from the throttle valve opening degree θ and its rate of change, but even if it is determined based on either quantity, the driver's will will be reflected, so it is not effective for the time being. Moreover, instead of the throttle valve opening degree, an amount representing the driver's requested output, such as an accelerator operation amount, may be used.

It should be noted that the above description is merely an example of application of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a device to which the present invention is applied. FIG. 2 is a sectional view showing the magnetic particle type electromagnetic clutch shown in FIG. 1 in detail. FIG. 3 is a diagram showing the transmission characteristics of the electromagnetic clutch shown in FIG. 2. 4 and 5 are flowcharts illustrating the operation of the apparatus of FIG. 1. FIG. 6 is a diagram showing an example of the relationship used when determining the target meat rotation speed in the flowchart of FIG. 5. 7 to 12 are diagrams showing the relationships used when determining each correction value in the flowchart of FIG. 5, respectively. FIG. 13 is a diagram showing the relationship used when determining the gain K in the flowchart of FIG. 4. FIG. 14 is a main part of a flowchart explaining the operation of another example to which the present invention is applied. 10: Engine 16: Magnetic particle electromagnetic clutch Applicant
Toyota Motor Corporation Figure 2R Figure 3 Figure 4 Figure 13 Figure 14

Claims (4)

[Claims] (1) When starting a vehicle equipped with a magnetic particle electromagnetic clutch,
When controlling the excitation current supplied to the magnetic particle type electromagnetic clutch so that the input side rotation speed becomes the target meet rotation speed, the target meet rotation speed is determined from a predetermined relationship between the required output of the vehicle and the required output. 1. A control method for a magnetic particle type electromagnetic clutch for a vehicle, characterized in that the control method is determined based on at least one of the rate of change of the magnetic particle type electromagnetic clutch for a vehicle. (2) The target rotational speed is corrected in response to the operation of a driving performance selection switch that selects the driving performance of the vehicle, such as economical driving or power driving.
A method for controlling a magnetic particle type electromagnetic clutch for a vehicle as described in 2. (3) The method for controlling a magnetic particle type electromagnetic clutch for a vehicle according to claim 1, wherein the target rotation speed is corrected in accordance with a decrease in the output of the engine of the vehicle. (4) The method for controlling a magnetic particle type electromagnetic clutch for a vehicle according to claim 1, wherein the target meeting rotation speed is corrected according to a change in running resistance of the vehicle.