JPS61218839A - Control method for magnetic powder type electromagnetic clutch for vehicle - Google Patents

Abstract

PURPOSE:To suppress the torque variation while preventing degradation of fuel consumption and durability by regulating the transmission torque of a magnetic powder type electromagnetic clutch such that the variation of the output from the output shaft of stepless transmission will match with predetermined target level. CONSTITUTION:The differential phase time DELTAt between the rotary signals SR3, SR4 from the rotary sensors 54, 56 near the input shaft of a magnetic powder type electromagnetic clutch 14 or the crank shaft 12 and the output shaft or the input shaft 18 is compared with the differential phase time DELTAt<-1> in previous cycle through electromagnetic clutch control routine thus to calculate the phase variation delta. If the phase variation delta is larger than predetermined level A, the correcting amount of basic control of said clutch 14 is updated to previous level. While when it is smaller than said level A, the slippage is calculated to update the correcting level accordingly.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for controlling a 6I powder type electromagnetic clutch for a vehicle equipped with a continuously variable transmission.

Prior Art In vehicles equipped with a continuously variable transmission that continuously changes the speed of the engine and transmits it to the drive wheels, the speed ratio of the continuously variable transmission is adjusted so that the required output is generated on the minimum fuel efficiency curve of the engine. There is a special feature that allows high fuel consumption efficiency to be obtained because the fuel consumption can be changed.

However, in this type of speed ratio control, the engine's low rotation and high load range, which has high fuel consumption efficiency, is used, but in such a range, the average engine output is not sufficient to drive the vehicle. Even if there is engine output fluctuation (
There is a problem in that the driveability is impaired due to vibration caused by the pulsation of the output torque, making it impossible to use such a low rotation range.

On the other hand, the output of the engine is transmitted to the continuously variable transmission via the magnetic particle type electromagnetic clutch, and the magnetic particle type electromagnetic clutch is operated at a variable rotational speed due to torque fluctuations of the input shaft rotational speed (variation range ΔNe from the average value). A technology has been developed that eliminates torque fluctuations on the output shaft of magnetic particle electromagnetic clutches by controlling the clutch output shaft to rotate at a rotation speed lower than the input shaft by a set slip rotation speed N3 greater than the set slip rotation speed N3. has been done. For example, the one described in Japanese Unexamined Patent Publication No. 58-657 is one such example.

Problems to be Solved by the Invention However, this conventional control method causes slippage in the clutch that is larger than the amount of fluctuation in the output torque of the engine. Although it has the characteristics of being suppressed, it has the following disadvantages. That is, (1) since the slipping rotational speed must be set larger than the varying rotational speed of the input shaft of the magnetic particle electromagnetic clutch, the engine rotational speed increases by the amount of slippage, and fuel consumption efficiency decreases. That is, as shown in FIG. 5, as the excitation current for the magnetic particle type electromagnetic clutch decreases, the torque fluctuation of the continuously variable transmission output shaft also decreases, but the fuel consumption efficiency also sharply decreases accordingly. For this reason, the effect of improving fuel consumption efficiency by operating the engine in a low rotation and high load range using a continuously variable transmission is offset. (2) Vehicle vibration and muffled noise caused by torque fluctuations that impair drivability are caused by problems on the continuously variable transmission output shaft, and even under the same engine operating conditions, The amount of torque fluctuation that must be absorbed by the magnetic particle type electromagnetic clutch differs depending on the speed ratio of the continuously variable transmission. In other words, as shown in Fig. 5, the torque fluctuation on the continuously variable transmission output shaft is determined by the speed ratio (output shaft rotational speed /
When the input shaft rotational speed is small, the torque fluctuation on the output shaft is larger. Therefore, in the conventional case, if the sliding rotation speed of the magnetic particle type electromagnetic clutch is set so that suitable drivability can be obtained even when the speed ratio becomes small, the magnetic particle type electromagnetic clutch is used in the region where the speed ratio is large. This will cause unnecessary slippage and reduce fuel consumption efficiency. (3) Furthermore, as described above, since the rotational speed difference must be set relatively large, the amount of heat generated within the magnetic particle type electromagnetic clutch increases, and there is a possibility that its durability may decrease.

Means for Solving the Problems The present invention has been made against the background of the above circumstances, and its gist is to transmit the output of the engine to a continuously variable transmission operatively connected to the drive wheels. A method of controlling a magnetic particle type electromagnetic clutch for a vehicle that transmits transmission torque, the transmission torque of the magnetic particle type electromagnetic clutch being adjusted so that an output fluctuation of an output shaft of the continuously variable transmission matches a predetermined target fluctuation value. There is a particular thing.

Operation and Effect of the Invention In this way, the transmission torque of the magnetic particle type electromagnetic clutch is adjusted so that the output fluctuation of the output shaft of the continuously variable transmission matches the predetermined target fluctuation value. Slip in the clutch is necessary and minimized. Therefore,
Compared to the case where a magnetic particle type electromagnetic clutch is made to slip so as to obtain a slipping rotational speed larger than the fluctuating rotational speed of the engine, the engine rotational speed is suppressed, and slippage is necessary and minimized according to the speed ratio. As a result, fuel consumption efficiency can be greatly improved. As a result of necessary and minimal slippage, the amount of heat generated within the magnetic particle type electromagnetic clutch is reduced, and its durability is greatly improved.

The output fluctuation of the output shaft of the continuously variable transmission may be detected based on the actual torque fluctuation or rotational fluctuation of the output shaft, but the actual speed ratio of the continuously variable transmission may be detected based on the actual torque fluctuation or rotation fluctuation of the output shaft. Alternatively, it may be calculated based on the actual slip amount of the magnetic particle type electromagnetic clutch.

In such a case, there is an advantage that a torque sensor for detecting torque fluctuations of the output shaft, a rotation sensor for detecting rotational speed fluctuations, etc. are not required.

Further, the target fluctuation value may be a constant value determined to achieve both drivability and fuel consumption efficiency, but it is determined based on the actual required output of the vehicle and the vehicle speed from a predetermined relationship. It's okay to be. In such a case, in a region where fuel economy is particularly important in terms of required output and vehicle speed, it is possible to perform control so as to tolerate slight torque fluctuations and reduce slippage.

Further, when adjusting the transmission torque of the magnetic particle type electromagnetic clutch, a basic control amount is determined to the extent that the actual output torque of the engine can be transmitted, and the output fluctuation of the output shaft of the continuously variable transmission is determined in advance. The final control amount may be obtained by correcting the basic control amount so that it matches the determined target fluctuation value.

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

In FIG. 1, a crankshaft 12 of an engine 10 is shown.
is connected to an input shaft 18 of a belt type continuously variable transmission 16 via a magnetic powder type electromagnetic clutch 14. The magnetic particle type electromagnetic clutch 14 fills the gap between the input rotating body 20 and the rotor 22 with magnetic particles by the magnetic force of the excitation coil 24, so that a transmission torque corresponding to the excitation current flowing through the excitation coil 24 is generated. It is obtained according to certain transfer characteristics. The belt type continuously variable transmission 16 also includes variable pulleys 28 and 30 with variable effective diameters provided on the input shaft 18 and output shaft 26, respectively, and a transmission belt 32 wound around the variable pulleys 28 and 30. The speed ratio (rotational speed of output shaft 26/rotational speed of input shaft 18) is changed by changing the effective diameters of variable pulleys 28 and 30 by a hydraulic device (not shown). The output shaft 26 of the belt type continuously variable transmission 16 is connected to a final reduction gear 34 including an intermediate gear and a differential gear.
is operatively coupled to the drive wheels 36 of the vehicle via the
The rotation of the engine 10 is controlled by the magnetic particle type electromagnetic clutch 14. Belt type continuously variable transmission16. The signal is transmitted to the drive wheels 36 via the final reduction gear 34.

A throttle sensor 40 for detecting the opening degree of the throttle valve 38 is provided in the intake pipe of the engine IO, and a throttle signal Sθ representing the throttle valve opening degree θ7N is sent to the A/D converter 44 in the controller 42. Supplied. Igniter 4 attached to engine 10
6, an ignition signal S■ corresponding to an ignition pulse for the engine 10 is supplied to an I/F circuit 48 in the controller 42 in order to detect the engine rotational speed Ne.

Furthermore, rotation sensors 50 and 52 for detecting the rotational speeds of the input shaft 18 and output shaft 26 of the belt type continuously variable transmission 16 are arranged near the variable boolean IJs 28 and 30. and 52, pulse-like rotation signals SR1 and SR2 having a period corresponding to the rotational speed of the input shaft 18 and the output shaft 26 are supplied to the I/F circuit 48.

The rotation signal SR2 is also used to detect the traveling speed of the vehicle. Further, a crankshaft 12 which is an input shaft of the magnetic particle type electromagnetic clutch 14 and an input shaft 1 which is an output shaft.
Rotation sensors 54 and 56 are provided in the vicinity of 8 to detect the respective reference positions, and these rotation sensors 54 and 56 supply rotation signals SR3 and SR4 months/F circuit 48. These rotational signals SR3 and SR4 are used to detect the phase difference between the input shaft and the output shaft of the magnetic particle type electromagnetic clutch 14, in other words, the slippage (rotational speed difference or rotational speed difference per unit time).

The I/F circuit 48 includes a clock and a counter for counting the phase time difference ΔL between the rotation signals SR3 and SR4, and sequentially calculates the phase time difference Δt! 10 output to port 68.

The controller 42 is a CPU 58. ROM60°RAM6
2, the CPU 58 executes signal processing according to a program stored in advance in the ROM 60 while utilizing the temporary storage function of the RAM 62, and
A control signal is supplied to the V/I converter 66 via the /A converter 64, and the magnetic particle type electromagnetic clutch 14 is supplied from the V/I converter 66 to the V/I converter 66.
A control current is supplied to the excitation coil 24 of. Also, C.P.
The O58 executes signal processing according to a program stored in advance in the ROM60, and supplies a control signal to a speed ratio control device provided in the hydraulic circuit of the belt type continuously variable transmission 16 via an interface (not shown). The speed ratio of the continuously variable transmission 16 and its rate of change are controlled. Normally, a data map for determining the target rotation speed of the engine 10 on the minimum fuel consumption rate curve is recorded in the ROM 60, and the target engine rotation speed is determined from the data map based on the throttle valve opening and the vehicle speed. Then, the speed ratio of the belt type continuously variable transmission 16 is changed so that the actual engine rotation speed and the target engine rotation speed match.

The control operation of the controller 42 for the magnetic particle type electromagnetic clutch 14 will be described below.

FIG. 2 shows an electromagnetic clutch control routine executed by interrupting in response to the rotation signal SR3 or SR4. First, when step Sl is executed, it is determined whether the clutch is in a half-clutch state or not. Ne and input shaft 1
The determination is made based on the difference from the rotational speed Nin of No. 8 or the phase time difference. If the clutch is in a half-clutch state, the start control routine of step S2 is executed, and the transmission torque of the magnetic particle electromagnetic clutch 14 is controlled so as to obtain suitable drivability and fuel consumption efficiency when starting the vehicle. .

However, if it is determined in step S1 that the clutch is not in a half-clutch state, the vehicle is in a running state after the clutch is engaged, so steps 83 and subsequent steps are executed to absorb output fluctuations of the engine 10. In step S3, the engine rotational speed Ne, vehicle speed V, and throttle valve opening θa□ are read based on the ignition signal S[, rotation signal SR2, and throttle signal Sθ, while the speed of the belt type continuously variable transmission 16 is read. The ratio e is determined based on the rotation signals SRI and SR2 and is read. In the following step S4, the average output torque T of the engine lO
e is calculated and read from a well-known relationship based on the throttle valve opening 6□ and the engine rotational speed Ne.

The average output torque Te may be detected by providing a torque sensor.

In the subsequent step S5, the basic control amount VcL0 is determined based on the average output torque Te obtained in step S4 using the following equation (1).

VCL' = k + (T e + ΔT) −
·--(11 However, k is a constant. ΔT is the torque difference between the peak value and the average value of the output torque of the pulsating engine 10.

(Formula 11 basically determines the excitation current for transmitting the output torque of the engine 10 to the belt-type continuously variable transmission 6, and the formula 1 above is based on the torque transmission characteristics of the magnetic particle electromagnetic clutch 14. It is determined.

Moreover, although a constant value determined in advance may be used for T in the above, it may be an actually detected value.

In step S6, the phase time difference Δt is read, and in step S7, the phase change amount δ( Δt) is calculated.

δ(Δ1)=Δ[-Δ1- (2) In step S8, it is determined whether the phase change amount δ(ΔL) is larger than a predetermined constant value A, and if it is larger, Since it is considered that the slippage in the magnetic particle type electromagnetic clutch 14 is too large and the durability and fuel consumption efficiency are deteriorated, the correction value is updated to the previous correction value Δvcl″l.In other words, the correction value is held constant. This state of excessive slipping may occur due to a delay in the rise of the clutch transmission torque when the accelerator pedal is suddenly depressed.In step S8,
If it is determined that the phase change amount δ(Δt) is not larger than the constant value A, step SIO is executed, and the slip amount δS is calculated from (3) 2 based on the phase time difference Δt and the engine rotation speed Ne. Calculated. Here, if the period of the rotation signal SR3 is T1 and the period of the rotation signal SR4 is Tb as shown in FIG. =Tb-Ts=l/Ni++-1/
N e = (N e - Ntn) / N e x Nih, and N e - Nlfl = δ (Δt) Ne - Nin. The left side of the above equation is the slip amount δS, and also Ne, N
Since t n, equation (3) is derived.

δS=δ(Δt)Ne” (3) In this way, since it is sufficient to measure the slip δS at about 0 to 30 rpm, the slip amount δS can be detected with high accuracy. It is also possible to directly determine the rotational speed Ne of the input shaft 18 and the rotational speed NJfi of the input shaft 18, and detect the amount of slippage from the difference between them.
Since there is a 10x change from 0rpa+ to 6000rpm, for example, a single 8-bit timer counter
．． If a clock pulse of 4 μsec is detected, 6
It is unavoidable that an error of 231 rpra per 1 bit occurs at 000 rpm.

In step Sll, it is determined whether the slip amount δS obtained in step SIQ is large enough to affect the heat generation amount of the magnetic particle type electromagnetic clutch 14 on the transmission characteristics and durability. That is, in general, the energy E per unit time consumed by the magnetic particle type electromagnetic clutch 14 and the amount of heat generated E' of the magnetic particle type electromagnetic clutch 14 are expressed by the following equations (4) and (5).

E=C'Te-ΔN (4) However, C1 is a constant, and ΔN is a rotation difference due to slippage.

However, C11 is the amount of heat dissipated from the clutch.

Since the magnetic particle type electromagnetic clutch 14 generates heat as shown in the above formula,
It is desirable that the device be put to practical use in the area of use shown in FIG. 4, and it is desirable that the amount of heat generated per unit time be E8 or less on a regular basis. Therefore, in step Sll, the product of the average output torque Te obtained in step s4 and the slip amount δS obtained in step S10 is
It is determined whether or not the value is larger than a predetermined constant value B corresponding to E1. If it is determined that the
Since the amount of slippage is too large from the viewpoint of heat generation in the clutch, step 312 is executed and the correction value is updated. The correction value in this case is the previous correction value Δ■.

Correction value ΔV increased by adding δvI to the river
(Updated to (), and the slippage of the magnetic particle electromagnetic clutch 14 is reduced.

In step Sll, it is determined that the product of the average output torque Te and the slip amount δS is smaller than B.

In this case, a step is executed to control the amount of slip in order to absorb fluctuations in the output of the engine 10.

That is, in step S13, the actual output fluctuation index IN
D is calculated from equation (6) based on the slip amount δS and the speed ratio e.

IND=-K・δS/e +K' ・, , 16
1 Generally, the rotational speed difference (slip) depending on the excitation current of the magnetic particle electromagnetic clutch 14, the torque fluctuation on the output shaft 26, and the fuel consumption rate of the vehicle have the relationship shown in FIG. 5, and this relationship can be expressed as the rotational speed. The differences can be summarized as shown in Figure 6. The above equation (6) is derived from the phenomenon shown in FIG. 6, and the actual output fluctuation index INO corresponds to the output fluctuation (torque fluctuation) on the output shaft 26 of the belt type continuously variable transmission 16. It is.

In step 314, the target output fluctuation index fND'
is determined based on the throttle valve opening θ7N and the vehicle speed V from a predetermined relationship. The relationship is shown in FIG. 7, for example, and is stored in advance in the ROM 60 as a data map. These relationships are determined so as to obtain the optimum value that achieves both drivability and economy as a whole. The slippage can be arbitrarily reduced only in a certain area. 7th
The top of the mountain in the figure indicates such an area. Note that the target output fluctuation index IND' may be a constant value.

In step S15, it is determined whether the actual output fluctuation index IND obtained in step SI3 is smaller than the target output fluctuation index IND' obtained in step S14, and if it is smaller, step 316 is executed to increase the amount of power. The correction value is updated to the corrected correction value, but if it is determined in step S15 that IND is larger than IND', step S17 is executed to update the correction value to the correction value that has been reduced. Then, in step 818, the correction value ΔVcL corrected as described above is the basic control amount vcI obtained in step S5. by adding the (final) control it V ct '
is determined, and in the subsequent step S19 the control amount y
A control signal representing cL* is passed through the D/A converter 64 to V
/I converter 66, and from the V/I converter 66, an excitation current corresponding to the magnitude of the control amount V (1" is supplied to the excitation coil 24 of the magnetic particle electromagnetic clutch 14. In other words, By repeating the above steps, the transmission torque of the magnetic particle type electromagnetic clutch 14 is feedback-controlled so that the actual output fluctuation index IND and the target output fluctuation index IND' match, and the output fluctuation on the output shaft 26 is optimized. It is considered to be a value.

In this way, according to this embodiment, the belt type continuously variable transmission 16
As a result, the amount of slip is adjusted based on the output fluctuation on the output shaft 26 of the engine 10 so as to obtain suitable drivability and economy, and as a result, the rotational speed of the engine 10 during running is set to the necessary and minimum value, Fuel consumption efficiency is greatly improved, and the slippage of the magnetic particle electromagnetic clutch 14 is minimized, thereby effectively preventing changes in transmitted torque and deterioration in durability caused by heat generation.

Although one application example of the present invention has been described above, the present invention can also be used in other embodiments.

For example, in the above-described embodiment, the control amount VC1' may be determined by directly increasing or decreasing the deviation between the actual output variation index IND and the target output variation index IND0.

Further, in the above embodiment, the actual output fluctuation index IND corresponding to the output fluctuation on the output shaft 26 is calculated from the slip amount δS and the speed ratio e of the belt type continuously variable transmission 16.
Actual output fluctuations on the output shaft 26 may be directly detected using a torque sensor or the like.

Further, the relationship for determining the target output fluctuation index IND' can be determined in various ways as necessary, and the above equation (6) for determining the output fluctuation index END' is based on the actual vehicle to be controlled. It can be changed in various ways depending on the characteristics and the like.

Further, the rotational speed difference between the input shaft and the output shaft of the magnetic particle type electromagnetic clutch 14 can be calculated by measuring the period Tc of the temporal change of the phase time difference Δt, as shown in FIG.

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 flowchart illustrating the operation of the apparatus of FIG. 1. FIG. 3 is a time chart showing a rotation signal for detecting slippage of the electromagnetic clutch in the device shown in FIG. FIG. 4 is a diagram showing the practical range of heat generation of the magnetic particle type electromagnetic clutch in the device of FIG. 1. FIG. 5 is a diagram showing the rotational speed difference, torque fluctuation, and fuel consumption rate with respect to the excitation current of the magnetic particle type electromagnetic clutch in the apparatus of FIG. 1. FIG. 6 is a diagram summarizing the characteristics shown in FIG. 5 with respect to the rotational speed difference. FIG. 7 is a diagram showing the relationship used to determine the target output fluctuation index in FIG. 2. FIG. 8 is a diagram illustrating another example of determining the rotational speed difference of the magnetic powder type electromagnetic flanch in FIG. 1. 10: Engine 14: Magnetic powder electromagnetic clutch 26:
Output shaft e: Speed ratio δS: Slip amount ■=Vehicle speed VC,': Basic control amount ■cL
″: Final control amount

Claims (4)

[Claims] (1) A method for controlling a magnetic particle type electromagnetic clutch for a vehicle that transmits the output of an engine to a continuously variable transmission that is operatively connected to a drive wheel, the method comprising controlling the transmission torque of the magnetic particle type electromagnetic clutch to the continuously variable transmission. 1. A method for controlling a magnetic particle type electromagnetic clutch for a vehicle, characterized in that the output fluctuation of the output shaft of the machine is adjusted so as to match a predetermined target fluctuation value. (2) A claim in which the output fluctuation of the output shaft of the continuously variable transmission is estimated based on the actual speed ratio of the continuously variable transmission and the actual slip amount of the magnetic particle electromagnetic clutch. A method for controlling a magnetic particle type electromagnetic clutch for a vehicle according to item 1. (3) The magnetic particle type electromagnetic clutch for a vehicle according to claim 1, wherein the target fluctuation value is determined based on the actual required output of the vehicle and the vehicle speed from a predetermined relationship. Control method. (4) When adjusting the transmission torque of the magnetic particle type electromagnetic clutch, a basic control amount is determined based on the actual output torque of the engine, and the output fluctuation of the output shaft of the continuously variable transmission is determined in advance. 2. The method of controlling a magnetic particle type electromagnetic clutch for a vehicle according to claim 1, wherein the basic control amount is corrected so as to match a target variation value determined to obtain a final control amount.