JPH0826932B2 - Shift control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a shift control device for a continuously variable transmission, and more particularly to a deviation between the actual engine speed and the target engine speed by PI or PI.
The present invention relates to a shift control device for a continuously variable transmission that is corrected by D operation means.

[Prior art and its problems]

Conventionally, various continuously variable transmissions such as a V-belt type continuously variable transmission and a toroidal type continuously variable transmission have been proposed. As a shift control method thereof, an engine speed or a gear ratio is used as a control amount, and this is used as a PID operation means. It is known to perform feedback control by using.

The PID operating means is used to eliminate the problem that a steady deviation and a phase delay remain with respect to the target value in the proportional operation (P operation), and is used as a feedback signal in addition to a signal proportional to the output of the system. It is a signal obtained by adding a signal obtained by integrating the output of the above and a signal obtained by differentiating the output.

However, delay control or overshoot is likely to occur when the PID operation means is used to perform shift control of the continuously variable transmission, especially when kickdown is performed. For example, if the controlled variable is the engine speed, and if the engine speed before the kickdown is higher than the target value, the integrator of the PID operating means has a falling component of the engine speed. If the engine is downed, the rise of the engine speed with respect to the target value after kickdown will be delayed and the response will be delayed. On the contrary, when the engine speed before the kickdown is lower than the target value, the integrator has an increasing component of the engine speed, so that the engine speed overshoot with respect to the target value after the kickdown is likely to occur.

[Object of the Invention]

The present invention has been made in view of the above problems, and an object thereof is to provide a shift control device for a continuously variable transmission that can prevent delay in response and overshoot when there is a large state change such as kickdown. To provide.

[Structure of Invention]

In order to achieve the above object, the present invention determines the deviation between the actual engine speed and the target engine speed as PI or PID.
In a transmission control device for a continuously variable transmission that is corrected by operating means and feedback-controlled so that the actual engine speed approaches the target engine speed, means for detecting the rising speed of the target engine speed and PI or PID operation And an integrator reset means for issuing a reset signal for clearing the integrator of the means, wherein the integrator reset means issues a reset signal when the rising speed of the target engine speed exceeds a set value. It is a thing.

That is, when the increase speed of the target engine speed exceeds the set value, such as during kickdown, the integrator of the PI or PID operating means is cleared, in other words, by not reflecting the information before kickdown. , To improve responsiveness and prevent overshoot.

Note that, as is well known, the PID operating means is a P operating means for outputting a signal proportional to the input, an I operating means for outputting a signal obtained by integrating the input with time, and a D operating means for outputting a signal obtained by differentiating the input with time. The feedback control means is used together with the operation means, and the PI operation means is the feedback control means not including the D operation means in the PID operation means.

[Explanation of Example]

FIG. 1 shows a schematic structure of a V-belt type continuously variable transmission which is an example of the continuously variable transmission according to the present invention, in which a crankshaft 2 of an engine 1 is connected to an input shaft 4 via a damper mechanism 3. . An external gear 5 is fixed to an end portion of the input shaft 4, and the external gear 5 meshes with an internal gear 6 fixed to a drive shaft 11 of the continuously variable transmission 10, so that the power of the input shaft 4 is transmitted. The speed is reduced and transmitted to the drive shaft 11.

Drive side pulley 12 provided on the drive shaft 11 of the continuously variable transmission 10.
And a driven pulley 14 provided on the drive shaft 13 and a V-belt 15 wound between both pulleys. The drive pulley 12 has a fixed sheave 12a and a movable sheave 12b,
A torque cam device 16 and a compression spring 17 are provided behind the movable sheave 12b. The torque cam device 16 generates a thrust force proportional to the input torque, and the compression spring 17
Generates an initial thrust to the extent that the V-belt 15 does not slacken, and these thrusts impart belt tension necessary for torque transmission to the V-belt 15. On the other hand, the driven pulley 14 also has a fixed sheave 14a and a movable sheave 14b, like the drive pulley 12, and a hydraulic chamber 18 for controlling the gear ratio is provided behind the movable sheave 14b. The hydraulic pressure to the hydraulic chamber 18 is controlled by a pulley control valve 43 described later.

A hollow shaft 19 is rotatably supported on the outer periphery of the driven shaft 13, and the driven shaft 13 and the hollow shaft 19 are disengaged by a starting clutch 20 composed of a wet multi-plate clutch. Starting clutch 20
The hydraulic pressure to the valve is controlled by a start control valve 45 described later.
A forward gear 21 and a reverse gear 22 are rotatably supported on the hollow shaft 19, and one of the forward gear 21 and the reverse gear 22 is connected to the hollow shaft 19 by a forward / reverse switching dog clutch 23. It is designed to be connected. Reverse idler shaft
24 is a reverse idler gear 25 that meshes with the reverse gear 22.
And another reverse idler gear 26 are fixed. A counter gear 28 that meshes with the forward gear 21 and the reverse idler gear 26 at the same time and a final reduction gear 29 are fixed to the counter shaft 27, and the final reduction gear 29 meshes with a ring gear 31 of the differential device 30. , Power output shaft
32 is transmitted.

The pressure regulating valve 40 regulates the hydraulic pressure discharged from the oil sump 41 by the oil pump 42 and outputs it as a line pressure to the pulley control valve 43 and the start control valve 45. The pulley control valve 43 and the start control valve 45 actuate the solenoids 44 and 46 by a control signal (for example, a duty control signal) output from the electronic control unit 60 to regulate the line pressure to respectively control the hydraulic chamber 18 of the driven pulley 14. The control oil pressure is output to each of the starting clutch 20 and Therefore, from the electronic control unit 60 to the solenoids 44,4
The gear ratio of the continuously variable transmission 10 and the torque transmission capacity of the starting clutch 20 can be freely controlled only by the control signal to 6.

FIG. 2 shows a structural diagram of the electronic control unit 60, in which 61 is a sensor for detecting the engine speed N _in (the rotation speed of the input shaft 4), and 62 is the vehicle speed V (the rotation speed of the output shaft 32). A sensor for detecting 63, a sensor for detecting the rotation speed N _out of the driven shaft 13 (the input rotation speed of the starting clutch 20 or the rotation speed of the driven pulley 14), and 64 for each shift of P, R, N, D, L Sensor to detect position, 6
5 is a sensor for detecting the throttle opening, the signals of the sensors 61-64 are input to the input interface 66,
The signal of the sensor 65 is converted into a digital signal by the A / D converter 67. 68 is a central processing unit (CPU), 69 is a read only memory (ROM) in which programs and data for controlling the pulley control solenoid 44 and the start control solenoid 46 are stored, and 70 is sent from each sensor. Random access memory (RA that temporarily stores signals and parameters
M), 71 is an output interface, and these CPU68,
The ROM 69, the RAM 70, the output interface 71, the input interface 66 and the A / D converter 67 are interconnected by a bus 72. The output of the output interface 71 is output as signal control to the pulley control solenoid 44 and the start control solenoid 46 via the output driver 73.

FIG. 3 shows a block diagram of the shift control system of the electronic control unit 60. Reference numeral 80 denotes a target engine speed determining means, which determines the target engine speed based on the throttle opening, the vehicle speed, the range signal and the like. 82 is a comparator of gain K _p , 83
Is a differentiator with a gain K _d , and 84 is an integrator with a gain K _I. These proportional device 82, differentiator 83, and integrator 84 enable PID operation means 8
Make up one. In addition, s is a Laplace operator.

As is well known, the proportional device outputs a signal proportional to the deviation between the input target engine speed and the actual engine speed, and the differentiator 83 outputs a signal obtained by differentiating the deviation,
The integrator 84 outputs a signal obtained by integrating the deviation. Above proportional device
82 has a function of adjusting gain, differentiator 83 has a function of increasing responsiveness, and integrator 84 has a function of eliminating steady deviation. The output signals of the PID operating means 81 are added and input to the control valve 43, which is the operation unit, and the control valve 43 provides the control hydraulic pressure according to the input signal to the continuously variable transmission (CVT) 10 to provide the continuously variable transmission. The engine speed after the shift control by 10 is negatively fed back to the target engine speed.

Reference numeral 85 is a means for calculating the time change rate of the target engine speed, 86 is an integrator reset means, and the integrator reset means 86 integrates the PID operating means 81 when the rising speed of the target engine speed exceeds a set value. Issue a reset signal to clear the instrument 84.

In the shift control system having the above structure, when the target engine speed changes as shown in FIG. 4a, when the increase rate of the target engine speed calculated by the time change rate calculation means 85 exceeds the set value, the integral The device reset means 86 outputs a reset signal as shown in FIG. 4b. That is, since the rising speed of the target engine speed always exceeds the set value during kickdown, the reset signal corresponds to that during kickdown. Since the integrator 84 of the PID operating means 81 is cleared by the reset signal, the information before kickdown is erased at the time of kickdown.

FIG. 5 is a response comparison diagram with respect to the target engine speed when the integrator 84 is cleared and when it is not cleared during kickdown. That is, the target engine speed N ₁
Assuming that a kickdown is performed while running at a higher point A, if the integrator 84 is not cleared,
Since the engine speed drop component corresponds to the shaded area in the figure, the engine speed cannot immediately increase to the target engine speed N ₂ after kickdown as shown by the broken line, resulting in a response delay. On the other hand, if the integrator 84 is cleared, the information before the kickdown is not reflected at all, so the engine speed is the target engine speed after the kickdown as shown by the solid line.
Immediately starts to rise to N ₂ , and excellent responsiveness is obtained.

Further, in FIG. 5, the case where the kickdown is performed while the vehicle is traveling at a point A which is slightly higher than the target engine speed N ₁ , is explained. However, contrary to the point A, the vehicle is traveling at a point lower than the target engine speed N _1. When the kickdown is performed, since the integrator 84 has an engine speed increasing component, overshoot with respect to the target engine speed N ₂ after the kickdown is likely to occur. Overshoot can be reduced by clearing 84.

In the present invention, the condition for clearing the integrator is not the increase speed of the throttle opening but the increase speed of the target engine speed. This is because when the amount of change is small, if the integrator is cleared when the rate of increase in the throttle opening exceeds the set value, a deviation with respect to the target engine speed tends to remain in the L range.

Further, although the shift control device using the PID operating means has been described in the above-described embodiment, the invention can be similarly applied to the case where the PI operating means is used.

〔The invention's effect〕

As is clear from the above description, according to the present invention, the integrator reset means for issuing a reset signal for clearing the integrator of the PI or PID operation means is provided, and the integrator reset means increases the target engine speed. Since the reset signal is issued when the speed exceeds the set value, it is possible to quickly reach the target engine speed and prevent overshoot without reflecting the information before the kickdown at the time of kickdown.

[Brief description of drawings]

FIG. 1 is a schematic view of a V-belt type continuously variable transmission to which the present invention is applied, FIG. 2 is a block diagram of an electronic control unit, FIG. 3 is a block diagram of a shift control system of the electronic control unit, and FIG. 4a. , Fig. 4b is a time change diagram of the target engine speed and the reset signal, Fig. 5
The figure is a response comparison diagram with respect to the target engine speed when the integrator is cleared and when it is not cleared. 1 ... Engine, 10 ... Continuously variable transmission, 42 ... Pulley control valve,
44 ... Solenoid for controlling pulley, 60 ... Electronic control unit, 80 ...
Target engine speed determining means, 81 ... PID operating means, 82 ...
Proportionator, 83 ... Differentiator, 84 ... Integrator, 85 ... Time change rate calculating means, 86 ... Integrator resetting means.

Claims (1)

[Claims] 1. A continuously variable transmission, wherein a deviation between an actual engine speed and a target engine speed is corrected by PI or PID operating means, and feedback control is performed so that the actual engine speed approaches the target engine speed. The shift control device is provided with means for detecting a rising speed of the target engine speed and integrator reset means for issuing a reset signal for clearing the integrator of the PI or PID operating means, and the integrator reset means is a target A shift control device for a continuously variable transmission, wherein a reset signal is issued when an increase speed of an engine speed exceeds a set value.