JPH02197434A - Controller for power train - Google Patents

Abstract

PURPOSE:To prevent recurrence of slip, when slip control of driving wheel is completed, by regulating return to the speed change characteristic for normal running from the speed change characteristic for slip control expanding its high speed step range, according to the running condition. CONSTITUTION:A controller for power train of a vehicle transmits engine power to a driving wheel B through an automatic transmission A. In this case, a slip quantity of the driving wheel B against the road surface is detected by a means C. Further, a mean D controls slip of the driving wheel B to end, based on the detected signal from the means C. When the means D controls slip, it is changed to a speed change pattern for slip control by a means E. Meanwhile, when the slip control is completed, return to a speed change pattern for normal running is regulated by a means G, according to the running condition detected by a means F. A speed change pattern for slip control further expands the high speed step range.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a power train control device, and more particularly to slip prevention of a vehicle equipped with an automatic transmission.

(Prior Art) Preventing the drive wheels from slipping excessively on the road surface is effective in effectively obtaining the propulsion force of the vehicle and in terms of safety by preventing spin. In order to prevent excessive slippage of the drive wheels, it is sufficient to reduce the torque applied to the drive wheels, which causes the slippage.

Conventionally, methods for performing this type of slip control are disclosed in Japanese Patent Application Laid-Open No. 58-16948 or Japanese Patent Application Laid-Open No. 60-56.
There is one shown in Publication No. 882.

Both of the technologies disclosed in these publications utilize the application of braking force to the drive wheels by the brake and the reduction in the output of the engine itself (reduction in generated torque) to reduce the torque applied to the drive wheels. This is how it is done. More specifically, in the method disclosed in Japanese Patent Application Laid-open No. 58-16948, when the slip of the drive wheel is small, only the braking of the drive wheel is performed, but when the slip of the drive wheel becomes large, this drive wheel is braked. In addition to braking, the output of the two engines is reduced. Also, JP-A-60-56662
In the system of the publication, when the slip of only one side of the left and right drive wheels is large, braking is applied only to the drive wheel of the one side with the large slip, while when the slip of both the left and right drive wheels is large. The system brakes the drive wheels on both sides and reduces the engine output.

Furthermore, in many recent vehicles, the output of the engine is transmitted to the drive wheels via a multi-stage automatic transmission. As seen in Japanese Unexamined Patent Publication No. 60-176828, it has already been proposed to shift up the gear ratio to a high speed gear in synchronization with the start of the slip control described above.

According to this, since the torque applied to the driving wheels is reduced by upshifting, the efficiency of slip convergence due to engine output reduction or braking force application is increased.

(Problems to be Solved by the Invention) However, if the upshift is performed on the condition that the slip control is started, there is a possibility that the downshift will occur when the slip control ends. In other words, automatic transmissions automatically shift gears based on predetermined shift characteristics, and the above-mentioned upshifts, that is, upshifts that are conditioned on the start of slip control, are performed during normal driving. This is nothing more than forcibly changing the speed change characteristics of the time.

For this reason, when the slip control is ended, the shift characteristics are switched to those during normal driving, and it is conceivable that a downshift is performed as a result of this change in shift characteristics. Then, when such a downshift is performed, the torque applied to the drive wheels increases again, and there is room for improvement from the viewpoint of slip convergence.

Therefore, one object of the present invention is to provide a speed change control for an automatic transmission that has a speed change characteristic for normal driving and a speed change characteristic for slip control, and to prevent the reoccurrence of slips due to termination of slip control. The purpose of the present invention is to provide a power train control device.

(Means and effects for solving the problems) In order to achieve the above object, the present invention has the following features.

As shown in Figure 1.

The premise is a vehicle powertrain control system that transmits engine output to the drive wheels via an automatic transmission.

a slip detection means for detecting the magnitude of slip of the driving wheel with respect to one road surface; and upon receiving a signal from the slip detection means, when the slip of the driving wheel is large, the torque applied to the driving wheel is reduced to reduce the torque applied to the driving wheel. slip control means for converging excessive slip; and a shift pattern for changing shift characteristics for normal driving without slip control to shift characteristics for slip control when slip control is performed by the slip control means; a changing means; and a shift pattern return regulating means for regulating the return from the slip control shift characteristic to the normal driving shift characteristic according to the driving condition when the slip control by the slip control means is completed. The transmission characteristic for slip control is configured such that a high speed range is expanded compared to the transmission characteristic for normal driving.

With the above configuration, depending on the operating state, even if the slip control by the slip control means ends, the restoration of the speed change characteristics that is performed at the same time as the end of the slip control is restricted.

The gear shift pattern return regulating means is defined in claim (2).
As shown in , it may be due to the engine load. In other words, if the shift characteristics are restored when the engine generated torque is large, and a downshift is performed in conjunction with this restoration, the impact on the driving wheels may be Torque will increase and slip may occur again. In addition, as claimed in claim (3), the shift pattern return regulating means is such that if the shift characteristics are restored, a downshift would be performed as a result of this restoration, the shift pattern may be changed to the shift characteristics for normal driving. It may also be something that restricts return.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 2 is a schematic diagram showing a device that is an embodiment of the present invention. The device of this example is a device mounted on a rear-wheel drive automobile, and the figure shows only a schematic diagram showing a device that is an embodiment of the present invention. As shown in Figure 0, which only shows some major components, the output of an engine 1 mounted on the front of the vehicle body is transmitted to the rear wheels 3 via an automatic transmission 2 equipped with a multi-stage transmission mechanism. The configuration is as follows. Intake pipe 4 for sending intake air into the combustion chamber of engine 1
A throttle valve 5 is disposed inside the throttle valve 5.
is driven by an actuator 6 typified by a step motor or the like. A speed sensor 7 for detecting the rotation speed N (drive) of the automatic transmission 2 is arranged on the output shaft of the automatic transmission 2, and a speed sensor 7 for detecting the rotation speed N (drive) of the automatic transmission 2 is also arranged on the axle 8 of the front wheel, which is a driven wheel.
A speed sensor 9 is arranged to detect the speed of the vehicle. On the other hand, an accelerator pedal 10 is arranged on the floor of the driver's seat, and an operation ff1a of this accelerator pedal is detected by an accelerator opening sensor 11. Further, the opening degree T H of the throttle valve 5 is detected by the throttle sensor 12 . Furthermore, an electromagnetically controlled hydraulic control circuit 13 that controls the gear position and lock-up clutch of the automatic transmission 2. That is, the solenoid valve 14 incorporated in the hydraulic control circuit 13
By turning ON and OFF the gear, a shift to a desired gear stage or lock-up can be performed.

On the other hand, the automatic transmission 2 described above is controlled by a control unit 15 composed of, for example, a one-chip microcomputer. On the input side of this unit 15, speeds N (driving) and N (following) are input from each of the above sensors.
, accelerator opening α.

A detection signal representing the throttle opening TH is input. Further, a traction switch 17 is disposed at the driver's seat so that whether or not to permit traction control, which will be described later, is to be permitted or not depends on the driver's will, and an ON-OFF signal from this traction switch 17 is input. The control unit 15 controls the engine 1 and the automatic transmission 2 according to a preset control program based on the human power information, and in this example, a traction control unit 16 is arranged. This unit 16 has a speed N (drive) and a speed N
(driven) is input, the occurrence of slip of the driving wheels 3 is detected from these values, and when the occurrence of slip is detected, traction control is executed on the condition that the traction switch 17 is turned on. The opening degree of the throttle valve 5 is controlled so as to reach the target throttle opening degree defined by the control. Further, when the traction control unit 16 is not performing the traction control, the traction control unit 16 operates according to the signal of the accelerator opening sensor II which is input via the control unit 15 or directly, and performs a preset process as shown in FIG. Accelerator pedal operation 1ea
- Control the opening of the throttle valve 5 with reference to the characteristics of the throttle opening TH. Furthermore, this traction control unit 16 supplies a signal TRC indicating whether or not traction control is being performed to the above-mentioned control unit 13.

Good 1 plate 1 Imperial road (i) Changing the speed change pattern Figures 3 and 4 show examples of the speed change pattern of the speed change control operation performed by the device of this example. 0 shows the shift pattern in the drive (D) range of )
Shift control is performed according to the shift pattern shown in the figure based on the throttle opening TH and the throttle opening TH. On the other hand, in the traction shift mode in which slip occurs in the drive wheels and traction control is executed, shift control is performed according to the shift pattern shown in FIG. 4. As can be seen from Figure 1, in this traction shift pattern, the high speed range is expanded compared to the normal shift mode, and there is no range in the lowest gear, l, so the gear is set to 1st. In this traction speed change mode, the speed change is performed using the speed N (driven) of the driven wheel and the accelerator opening degree α as parameters. This is to prevent a shift from occurring due to slip control. The reason why the accelerator opening degree a is adopted here is as follows. That is, when adjusting the engine output in slip control, if a factor related to this output, such as throttle opening TH, is used as a parameter of the shift characteristics, then the change in throttle opening TH due to slip control This makes it more likely that the gear will be changed. Then, the gears are likely to be shifted again due to the slip control of the drive wheels due to the change in the torque applied to the drive wheels as the gears are changed. In this way, there is a risk that upshifts and downshifts may be repeated frequently due to the interaction between slip control and gear shifting. Moreover, the reason why the speed of the driven wheel was adopted is as follows. In other words, if the shift is controlled based on the speed of the drive wheels when slip occurs, an upshift will be performed due to the increase in the rotation speed of the drive wheels due to the occurrence of slip, and the rotation speed of the drive wheels will increase as the slip converges. A downshift is performed by a decrease in . This is because unnecessary gear changes may occur.

- John 1 Next, the Traxidin control operation by the device of this example will be explained with reference to the flowchart of FIG. 5 and the characteristic diagram of FIG. 6.

In the control of this example, the traction switch 17 is
If the vehicle is turned to N and traction control is enabled,
Steps 5T12 to 20 are executed from step 5TII to perform preliminary calculations for determining the slip state of the driving wheels and estimating road surface μ.Next, steps 5731 to 33
Execute.

Estimate μ of the road surface. After this, step 5T41~
The target throttle opening TH. is calculated according to the slip state determined as 1 by executing step 51. In other words, traction control is performed when the amount of slip is large (SPI N=O, which will be described later), and when it is medium (SP I N=100, which will be described later), and traction control is performed when the amount of slip is small (SPI N=O, which will be described later).
(N=255) or when no occurrence occurs, normal control is performed.

A specific control operation will be explained with reference to the example shown in FIG.

(i) During time T I -72 First, at time T1, when the difference between the speed N (drive) of the driving wheel and the speed N (driven) of the driven wheel becomes larger than a preset value, the driving wheel It is determined that a large slip has occurred (step 5T12), and rOJ is input to the register 5PIN indicating the degree of slip (step 5
T19), then 500m5e in timer register TI
c is set, and the speed N (driven) of the driven wheel is set in the register N (step 5T20).

After this, the time set in the timer register is 500m5.
Calculate the increase ΔN in the rotation speed of the driven wheel during ec,
From this increase and the speed of the driven wheel, the value of μ of the running road surface is estimated (steps 5731 to 33). After this, the target rotation speed N- is calculated based on the estimated value of μ (step 5T45) .

Since the slip of the driving wheel is large now, the throttle opening degree is calculated from the speed N (driven) of the driven wheel (step 47).In this calculation, an upper limit of the throttle opening degree is set, and The throttle opening value for the same accelerator operation amount is set lower than in a state where no slip occurs (step 5T47), and the throttle opening THn calculated in this way becomes the target throttle opening TH・The opening degree TH of the throttle valve is controlled to be this value. That is, time T in FIG.
During such traction control, such as between T1 and T2, the value of the throttle opening T H is set low. Incidentally, the flag F shown in step 5T42 indicates whether traction control is being performed or not, and flag F=1 means that traction control is in progress, and flag F=
0 means no Traxidin control.

(i i) Between times T2 and T3 Next, by setting the throttle opening low in this way, the slip of the drive wheels is reduced to a medium level (
At time T2 in Figure 6), 330 m is stored in timer register T2.
5ec is set (step 5T14), and the contents of register 5PIN indicating the degree of slip are set to rloooJ (step 5T16).After this, after μ of the running road surface is estimated in the same manner as above, the above Until the time 330m5ec set in timer register '2 elapses, the target throttle opening TH is determined based on the speed N (driven) of the driven wheel, and the throttle opening TH is adjusted to this value. The throttle opening degree at this time, which is controlled (step S1''49), is set to be approximately an intermediate throttle opening degree between the control between time Tl-72 and the normal control.

During the period between times T1 and T3 mentioned above, the shift characteristics are set to the traction mode, which will be described later, and the fourth
Shift control of the automatic transmission is performed according to the shift pattern shown in the figure.

(iii) After time T3 Next, after the 330m5ec set in timer T2 has elapsed, the contents of register 5PIN are set to "225" (step 5T17), and this value indicates that the throttle opening is
The actual throttle opening is calculated based on the speed N (drive) of the driving wheels, and the actual throttle opening is feedback-controlled so as to match the calculated throttle opening (step 5T50).

Here, in this example to explain the outline of the feedback control, the target rotation speed is assumed to be V.

A value is set that is the sum of the driven wheel rotation speed FW and the slip rotation speed Δ■ set according to the road surface μ. Throttle opening TH・so that the actual rotation speed is controlled to this target rotation speed.
is feedback-controlled by the Pl-P method as shown by the following equation.

'r) II =STAG+P l (ENWR+
ENWR1) + IXENWR-D [(PRWR-P
RWR1)-(1)RWRl-r'RWR2)] -P2 (PRWR-PRWRI) In the above equation, 5TAG is the target throttle opening one control cycle ago, PRWR is the current drive wheel rotation speed, and PRWRl is Drive wheel rotation speed one control cycle before,
PRWR2 is the drive wheel rotation speed two control cycles ago. Further, ENWR is the difference between the target rotational speed MO and the current driving wheel rotational speed PRWR, and ENWRl is the difference one control cycle ago. Also, Pl is a proportional gain that affects responsiveness, and! is an integral gain related to stability, P2 is a proportional gain that responds to changes in the gain of the vehicle, etc., and D is a differential gain that responds to changes in the gain of the vehicle, etc. In this PI-Po Dl--comb blade type, Pl-1 ensures target followability and stability, and P2-D compensates for stability against external disturbances (throttle being controlled, changes in vehicle characteristics, etc.) be done.

The above traction control is performed when the accelerator is released (step 5T41) or at step 5T4.
3, when the slip condition becomes small (SPIN=255), the process is stopped and step 5
After resetting the flag F in step 2, step 5T
At step 53, the throttle opening degree is set in accordance with the depression of the accelerator. That is, the opening degree of the throttle valve 5 corresponds approximately to the amount of depression of the accelerator pedal 10.

7. The shift characteristics of the automatic transmission 2 are said to be different during normal driving (Figure 3) and during traction control (Figure 4), but the change in the shift characteristics, that is, after traction control is completed, The change from the traction control shift mode to the normal driving mode cannot be performed in the following manner.

First, in step S1''60, it is determined whether the flag F=] (whether traction control is being performed or not), and when it is determined that traction control is being performed (flag F=1), the process proceeds to step ST61. The transmission mode for traction control control (Fig. 4) is set in step 5T62, and then flag I is set (flag I
=1), this flag 1 represents the aspect of the speed change mode, and the flag ! Flag=1 means a speed change mode for traction control, and flag 1=0 means a speed change mode for normal driving.

Now, assuming that traction control has ended, flag F=
Since it is 0 (see FIG. 5, step 5T52),
Proceeding from step S7.60 to step 5T63, it is determined whether flag 1=1. Assuming that the shift mode has not been changed yet, flag I=1
(Transition mode for traction control)
If the answer is YES, proceed to 5T64, where it is determined whether or not the accelerator is depressed.If the accelerator is in the depressed state (ON state), the answer is YES.
Proceed to ST61. Conversely, if the determination in step 5T64 is No (accelerator pedal release), proceed to step 5T65, where the normal driving gearshift mode (Fig. 3) is set for the first time, and then flag I is reset. is performed (step 5766), that is, even if traction control ends, the shift mode is not immediately changed in response to this end, but only after the accelerator pedal 10 is released. The shift mode is now changed to the normal driving mode. Therefore, even if a downshift is made due to a change in the transmission mode (change to the normal driving transmission mode), the accelerator pedal 10 is not depressed, that is, the engine generated torque is small, so this shift It is possible to prevent a situation in which a large slip occurs again due to the down.

2-8 In this embodiment, the change of the speed change mode is restricted depending on whether or not a downshift occurs (step 5T7).
4), that is, even if the traction control ends (flag F = 0), the speed change mode is not changed immediately upon this end, but is changed from the traction control speed change mode (Fig. 4). If the shift mode is changed to the normal driving shift mode (Fig. 3), it is determined whether or not a downshift occurs due to this change.Step 5T7
4) Only when the result of this determination is that a downshift will not occur, the process proceeds to step 5T75, where the 1 normal driving shift mode is changed.

In the above embodiment, the traction control is terminated when the accelerator is released or the slip condition becomes small, but when the accelerator opening becomes less than the throttle opening. The same applies to those carried out in the same way.

(Effects of the Invention) As is clear from the above description, according to the present invention, it is possible to prevent the occurrence of a situation in which a slip occurs again due to a change in the speed change characteristics accompanying the end of slip control, and the vehicle Driving stability can be improved.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the present invention. FIG. 2 is an overall system diagram of the embodiment. Fig. 5 is a flowchart showing an example of traction control control. Fig. 6 is an explanatory diagram of traction control. Fig. 7 is a flowchart showing an example of control for changing the transmission characteristics. Fig. 8 is a flowchart showing an example of control for changing the transmission characteristics. A flowchart showing an example of control to change the transmission characteristics. Figure 9 is a throttle valve characteristic diagram during normal driving. : Automatic transmission: Drive wheel: Throttle valve: Drive wheel rotation speed sensor: Driven wheel rotation speed sensor: Accelerator Pedal: Accelerator opening sensor: Throttle opening sensor: Shift control unit: Traction control control unit

Claims (3)

[Claims] (1) A powertrain control device for a vehicle that transmits engine output to drive wheels via an automatic transmission, comprising: a slip detection means for detecting the amount of slip of the drive wheels with respect to a road surface; and the slip detection unit. a slip control means that receives a signal from the means and reduces torque applied to the drive wheel to converge the excessive slip of the drive wheel when the slip of the drive wheel is large; and a slip control means that performs slip control by the slip control means. a shift pattern changing means for changing the shift characteristic for normal driving without slip control to a shift characteristic for slip control when the slip control is completed; a shift pattern return regulating means for regulating a return to the shift characteristic for normal running according to the driving condition, and the shift characteristic for slip control is set at a higher speed than the shift characteristic for normal running. A powertrain control device characterized by having an expanded area. (2) In claim (1), the shift pattern return regulating means regulates the return from the slip control shift characteristic to the normal driving shift characteristic when the generated torque of the engine is large. (3) In claim (1), the shift pattern return regulating means is configured to control the shift pattern when a shift from a high speed gear to a low gear is performed when the shift characteristic is returned from the slip control mode to the normal driving mode. , which regulates the restoration of the speed change characteristics.