JPS59113355A - Control method of stepless transmission gear - Google Patents

Abstract

PURPOSE:To improve response and to prevent the occurrence of over shoot, by a method wherein a difference in a deviation between an actual gear ratio and a desired gear ratio is calculated from a deviation at a present computing time and a deviation at a computing time of the plural number of times previously. CONSTITUTION:A difference between a desired gear ratio and an actual shifting ratio is calculated to set it as a deviation E0 (at 561). Thereafter, the deviation E0 is multiplied by a first constant K1 (at 562) to determine the value of (n) (at 563), and a difference between the deviation E0 and a deviation En at a computing time of (n) times previously is multiplied by a second constant K2 (at 564). Thereafter, K1.E0 and K2...(E0-En) are added to set it as a gear shifting speed signal, and it is decided (at 566) whether or not the summation value exceeds a given limit value. When the summation value exceeds the limit value, the limit value is set as a gear ratio signal, and if below the limit value, the summation value is set as the gear ratio signal as it is.

Description

[Detailed description of the invention] The present invention relates to a control method for a continuously variable transmission.

Generally speaking, in speed change control of a continuously variable transmission installed in a vehicle, the actual speed ratio is detected, the difference between this and the target speed ratio is calculated, and the speed change actuator is controlled to reduce this difference. It is done. When the accelerator pedal is rapidly depressed to obtain rapid acceleration, the continuously variable transmission must shift rapidly to improve responsiveness. For this purpose, there is a control method that controls the operating speed of the shift actuator of a continuously variable transmission according to the rate of change of the deviation between the actual gear ratio and the target gear ratio (i.e., the differential value of the deviation with respect to time). . For example, Japanese Patent Application No. 56-137826 filed by the present applicant discloses a device that performs the above-mentioned control using analog signals. In this case, since analog signals are used,
There is a time delay in the differentiation of the deviation, and the time during which the operating speed of the speed change actuator is increased continues for a certain amount of time. In other words, the shift actuator does not operate at a high speed only while the deviation between the actual gear ratio and the target gear ratio is changing (for example, only at the moment when the accelerator pedal is depressed), but the deviation stops changing. Afterward (after the accelerator pedal is stopped being depressed), the operating speed of the speed change actuator remains high for a predetermined period of time. Therefore, even if the deviation between the target gear ratio and the actual gear ratio changes very rapidly, the gear change remains constant for a certain period of time. Since the operating speed of the motor is fast, rapid gear changes can be performed. However, when attempting to perform similar control using digital control, the following problems arise. That is, in normal digital control, the following calculations are executed over and over again at very short time intervals of kt7. First, the deviation EO between the actual gear ratio and the target gear ratio at the time of the current calculation is calculated, and this deviation Eo is multiplied by a first constant. Further, the difference e between the current deviation Eo and the deviation E-1 at the previous calculation is calculated, and this is multiplied by a second constant KZ. Next, 2.e is added to Kl-Eo, and the operating speed of the speed change actuator is determined according to the value of 1.EO+KZ.

However, when the above 61j calculation is performed, Kl·e takes a large value only when the deviation Eo changes rapidly, and takes a small value during other calculations. For this reason, even though an amount corresponding to the difference e corresponding to the differential value of the deviation EO is added, there is practically no effect of increasing the operating speed of the speed change actuator.

That is, the operating speed of the shift actuator is controlled in proportion only to the deviation Eo, so the operating speed is slow and it takes time to shift. In addition, in a continuously variable transmission, a maximum operating speed of 1■ is generally set for the shift actuator in order to protect the belt etc. from shocks caused by rapid gear changes, and the shift actuator does not operate at speeds higher than that. It is so that it cannot be made to work. In this case, the time during which the operating speed of the shift actuator is increased is short, and its maximum speed is limited, so the shift speed becomes very slow.

The present invention calculates the difference in deviation between the actual gear ratio (or engine rotation speed) and the target gear ratio (or target engine rotation speed) from the deviation at the time of the current calculation and the deviation at the time of multiple previous calculations. The aim is to solve the problems mentioned above.

Hereinafter, the present invention will be explained based on accompanying drawings of FIGS. 1 to 4.

FIG. 1 shows a block diagram of a configuration for implementing the method of the present invention. Various signals 10 (e.g., heavy speed signal, engine rotational speed signal, throttle opening signal, etc.) indicating the driving state of the vehicle are input to the target gear ratio @ calculation device lOO, and the target gear ratio signal is calculated according to a predetermined calculation method. 11 is calculated. This target gear ratio signal 11 is input to a gear ratio deviation calculation unit 110. The gear ratio deviation calculation device 110 includes:
An actual speed ratio signal 21 calculated by the actual speed ratio presetting device 200 is also input. The gear ratio deviation calculation device 110 calculates the deviation Eo between the target gear ratio signal 11 and the actual gear ratio signal 21. A signal 12 indicating the deviation EO is sent to the multiplier 1
20, it is input to the acupuncture needle 3 part 140 and the deviation reading part 300. The multiplier 120 applies a first constant K to the deviation Eo,
is multiplied.

The deviation readout section 300 calculates the deviation E-n from the calculation n times before.
is taken out. Note that the value of n is determined by the delay number calculation device 3.
It is set by the command from 10. Delay count calculation device 3
Reference numeral 10 determines the value of n as described later based on a throttle type signal 10' indicating the operating state of the vehicle. The subtraction unit 140 calculates the deviation from the deviation Eo n times before @B-
n is subtracted. Next, the multiplication unit 150 performs the above subtraction i
A second fixed group QK2 is inserted into l'IE o - E-n. The value K16EO from the multiplier 120 and the multiplier 150
Adder 1 adds 2 m (E o-E-rl) to the value from
60 is added, and the added value is 1・Eo+ is added to 2@(EO
-E-yl) is sent to the shift speed command device 170. Based on this added value, the shift speed command device 170 commands the operating speed of the shift actuator 180 that is less than or equal to the maximum operating speed of the shift actuator described above. As a result, the speed change speed of the continuously variable transmission 190 is controlled.

The functions from the gear ratio deviation calculation device 110 to the addition section 160 are shown as a flowchart as shown in FIG. First, the difference between the target gear ratio and the actual gear ratio is calculated, and this is set as the deviation EO (561). Next, the deviation EO is multiplied by the first constant (56, 2), and then the value of n is determined by 1 (563), and the deviation Eo and the deviation E-n from the previous calculation are calculated.
The second constant is multiplied by 2 (564). Then,
2 ++ (E o - E - n) is added to K1·Eo and this is used as a shift speed signal (565). Then,
It is determined whether the added value is greater than or equal to a predetermined limit value (566). If the above added value exceeds the limit value,
The limit value is set as a shift speed signal (567). If the added value is less than or equal to the limit value, the added value is directly used as the shift speed signal. Next, for the next calculation, each deviation in the memory is replaced one by one with the deviation from the previous calculation (ie, E- to -1←E-K) (568).

Next, FIGS. 3(a) to 3(f) show how each signal changes when the above control is performed.

Assume that the target gear ratio signal changes in a stepwise manner as shown in FIG. 3(a). In this case, the actual gear ratio (that is, the actual gear ratio signal) changes as shown in FIG. 3(b). Therefore, the deviation E between the target gear ratio signal and the actual gear ratio signal is
o changes as shown in FIG. 3(C). Subtracting the deviation E-n in the nth previous operation from the deviation EO gives the third (d
) as shown in the figure. The value obtained by adding the deviation Eo multiplied by the first constant by 1 and the difference Eo-E-41 multiplied by the second constant I (2) is as shown in Figure 3(e). In addition, the value indicated by the broken line in Fig. 3(e) is the shift speed limit value.In the end, the shift speed signal is
f) The waveform will be as shown in the figure.

Therefore, even if the target gear ratio signal is changed stepwise, the gear change actuator operates at the maximum speed during time t1 (corresponding to n calculation times), and operates at the maximum speed during time t2. is decreasing. Therefore, the speed change actuator operates at high speed and speed changes are performed quickly.

For reference, changes in the signal when the difference is calculated from the difference between the deviation during the current calculation and the deviation during the previous calculation (i.e., when n = 1) are shown in Sections 4(a) to (). f
) shown in figure. The difference between this case and the example shown in FIG. 3 is that the difference appears only in the form of a very short pulse in the ff14 (d) diagram. For this reason, the fourth (f)
The time t1' in the figure is extremely short (equivalent to the time for one calculation). Therefore, the actual operating speed of the speed change actuator is slower than in the case shown in No. 3M, and the speed change response of the continuously variable transmission is poor.

Note that the value of n mentioned above is changed in accordance with the operating conditions as follows. In other words, 1. For example, in the case of operating conditions where the target gear ratio changes significantly (for example,
If the accelerator pedal is suddenly depressed, the shift lever
(such as when shifting from D range to L range), n
In the case of operating conditions where the value of n is increased and the target gear ratio changes relatively small, the (fi of n is decreased. By changing the value of n in this way, the target gear ratio changes significantly. The actual gear ratio changes quickly even when the change is small, and it is possible to prevent overshoots from occurring.In addition, the value of n is not changed and is fixed at a reasonable value. Of course, it is also possible to set it in advance.

In the embodiment described in -1-, control is performed based on the deviation between the target gear ratio and the actual gear ratio, but since the gear ratio and the engine rotation speed have a predetermined relationship, the target engine rotation speed It is clear that the same control as above can be performed based on the deviation between the actual engine speed and the actual engine speed.

As explained above, according to the present invention, the target gear ratio or the engine speed of the continuously variable transmission is determined according to the driving condition of the vehicle, and the actual gear ratio or engine speed of the continuously variable transmission is determined. The gear ratio is determined by detecting the actual engine rotation speed, and controlling the shift actuator of the continuously variable transmission based on 1) the subtraction gear ratio or the target engine rotation speed, and the actual gear ratio or the actual engine rotation speed. In a method of controlling a continuously variable transmission, a deviation between a target gear ratio or target engine rotation speed and an actual gear ratio or actual engine rotation speed is calculated as a digital signal, and a first constant is added to the deviation. , and calculate the difference between the deviation during the current calculation and the deviation during the calculation several times before, multiplying the difference by the second constant, and multiplying the deviation by the first constant. and,
Since the difference is multiplied by a second constant and the operating speed of the gear change actuator is controlled according to this added value, the actual gear ratio quickly follows the target gear ratio, improving responsiveness. It is possible to perform excellent control of the continuously variable transmission. Furthermore, the ``Yu'' effect is particularly effective when there is a limit to the operating speed of the speed change actuator. In addition, by changing the number of times according to the driving condition of the vehicle, it is possible to improve the responsiveness in all turning conditions and to prevent the occurrence of problems such as .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration for implementing the method of the present invention, and FIG. 2 is a flowchart 1 of the calculation according to the method of the present invention.
Figure 3 is a diagram showing changes in each signal caused by the method of the present invention, and Figure 4 is a diagram showing changes in each signal when not using the method of the present invention for comparison. It is. 100... Target gear ratio calculation device, 110... Gear ratio deviation calculation device, 170... Gear change speed command device, 180
...speed change actuator, 200...actual speed change ratio calculation device.

Claims (1)

[Scope of Claims] (1) Determining the target gear ratio of the continuously variable transmission plate or the target engine rotational speed according to the operating condition of the heavy vehicle, and detecting the actual gear ratio or the actual engine rotational speed of the continuously variable transmission. , in a continuously variable transmission control method that controls a gear ratio by controlling a gear change actuator of the continuously variable transmission based on a target gear ratio or a target engine rotation speed and an actual gear ratio or an actual engine rotation speed. , Calculate the deviation between the target gear ratio or target engine rotation speed and the actual gear ratio or actual engine rotation speed as a digital irises, multiply the above deviation by the first constant, and calculate the deviation at the time of the current calculation. The difference between and the deviation from the previous calculation multiple times is calculated, the difference is multiplied by a second constant, the deviation is multiplied by the first constant, and the difference is multiplied by the second constant ( A control method for a continuously variable transmission, which includes increasing the value of fi and controlling the operating speed of a speed change actuator according to this added value.2. 2. The control method for a continuously variable transmission according to claim 1, wherein the more the required operating state is, the more times the calculation is performed.