JPH01215634A - Transmission controller of continuously variable transmission - Google Patents

Abstract

PURPOSE:To maintain the integration compensating term to a constant value at the maximum or the minimum transmission ratio and prevent the overshoot of engine revolution by compensating the error between the actual value of an engine r.p.m. and the secondary target value with the integrating means only of a PI actuating means or the like. CONSTITUTION:A means 80 determines a primary target engine r.p.m. on the basis of the opening position of a throttle valve, the car speed and the mode range. A means 81 determines a secondary target engine r.p.m. on the basis of the primary target engine r.p.m., the car speed and each of the maximum and the minimum transmission ratio. Furthermore, a means 82 determines the reference quantity of operation in the constant state on the basis of the engine torque and the transmission ratio. The proportional device 86 of a PI actuating means 85 generates the signal proportional to the error between the primary target engine r.p.m. and the actual engine r.p.m. and regulates the gain. On the other hand, the integrator 87 of the PI actuating means 85 generates the signal obtained from the integration of the error between the secondary target engine r.p.m: and the actual engine r.p.m. and dissolves the constant error.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speed change control device for a continuously variable transmission, and particularly to a speed change control device for a continuously variable transmission.
This invention relates to a shift control device for a continuously variable transmission that performs correction by a D operating means and controls a shift control actuator in accordance with the correction value.

[Prior art and its problems]

Conventionally, various continuously variable transmissions such as belt-type continuously variable transmissions and toroidal continuously variable transmissions have been proposed, and the speed change control method uses the engine speed and gear ratio as control variables, and uses this as a PID operating means. It is known that feedback control is performed using .

As is well known, PID operation means uses a feedback signal in addition to a signal proportional to the output of the system in order to eliminate the problem of stationary deviation or phase delay remaining with respect to the target value in proportional operation (P operation). , is the sum of the integrated signal and the differentiated signal of the output of the system.

By the way, target values for engine speed and gear ratio are determined according to driving conditions such as throttle opening and vehicle speed, but since continuously variable transmissions have a range in which they can be changed, actual engine speed and It may not be possible to bring the gear ratio close to the target value.0 For example, if the target value is assumed to be the target engine speed Nm as shown by the broken line in Figure 6, the vehicle speed is v
Between A and ■, that is, within the shift control region, it is possible to reduce the actual engine speed to the target engine speed N, but when the vehicle speed is lower than vA and ■,
If it is higher, the speed change range is limited by the maximum speed ratio (Low) and the minimum speed ratio (High). In other words, while the vehicle is running at the maximum speed ratio and the minimum speed ratio, no matter how much speed change control is performed, it is impossible to bring the actual engine speed close to the target engine speed N.

Therefore, while driving at the maximum or minimum transmission ratio,
If the PID operating means continues to correct the deviation between the actual engine speed and the target engine speed N+t, the PID
When the integral correction term of the operating means overflows and shifts from the maximum gear ratio or the minimum gear ratio to the gear change region, the engine speed overshades with respect to the target value N, as shown by the arrow in Figure 6. There was a problem.

[Purpose of the invention]

The present invention has been made in view of the above problems, and its purpose is to
Eliminating overflow of the integral correction term of the ID operation means,
An object of the present invention is to provide a shift control device for a continuously variable transmission that can prevent overshoot of engine rotation when shifting to a shift region.

[Structure of the invention]

In order to achieve the above object, the present invention calculates the deviation of the engine speed or gear ratio from a target value by PI or PID.
In a shift control device for a continuously variable transmission that corrects a shift control actuator according to the correction value by an operating means, the shift control device includes a first target value determining means for determining a first target value according to operating conditions; a second target value determining means for determining a second target value that can be reached by comparing the first target value with a shift control area; and the first target value, and the integrating means corrects the deviation between the actual engine speed or the gear ratio and the second target value.

[Effect]

That is, excluding the integrating means, the PI or PID operating means corrects the deviation between the first target value and the actual value determined according to the operating conditions, and only the integrating means corrects the deviation between the actual value and the second target value. do. This second target value is a target value that can actually be reached and is determined by comparing the first target value and the gear change control area (between the maximum gear ratio and the minimum gear ratio), and for example, at the maximum gear ratio. is the target value corresponding to the maximum gear ratio,
At the time of the minimum gear ratio, the target value corresponds to the minimum gear ratio. In this way, the integral correction term is held at a constant value at the maximum or minimum gear ratio, so there is no risk of overflow, and it is possible to prevent engine speed overshoot when shifting to the next gear range. effective.

〔Example〕

FIG. 1 shows a schematic structure of an example of a continuously variable transmission according to the present invention. A crankshaft 2 of an engine 1 is connected to an input shaft 5 via a flywheel 3 and a damper f14. An external gear 6 is fixed to the end of the input shaft 5, and this external gear 6 meshes with an internal gear 7 fixed to the drive shaft 11 of the continuously variable transmission lO to transfer the power of the input shaft 5. The speed is decelerated and transmitted to the drive shaft 11.

The continuously variable transmission device 10 is composed of a driving side boot 2 provided on the drive shaft 11, a driven side boot 4 provided on the driven shaft 13, and a V-bell H5 wound between both pulleys. . The drive side boot 2 has a fixed sheave 12a and a movable loop 12b, and a gear ratio control oil chamber 16 for controlling the gear ratio is provided behind the movable sheave 12b.

On the other hand, the driven side boot i month 4 is similar to the driving side boo January 2,
It has a fixed sheave 14a and a movable sheave 14b,
Behind the movable sheave 14b, a load thrust control oil chamber 17 is provided which provides the belt 15 with the thrust necessary for torque transmission. The oil pressure in the gear ratio control oil chamber 16 and the load thrust control oil chamber 17 is controlled by a gear change control valve 43 and a load thrust control valve 45, which will be 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 connected and connected by a starting clutch 20 consisting of a wet multi-disc clutch. The oil pressure of the starting clutch 20 is controlled by a starting control valve 47, which will be described later. A forward gear 21 and a reverse gear 22 are rotatably supported on the hollow shaft 19, and a forward/reverse switching dog clutch 23 connects either the forward gear 21 or the reverse gear 22 to the hollow shaft 19. It is designed to be connected. A reverse idler gear 25 that meshes with the reverse gear 22 and another reverse idler gear 26 are fixed to the reverse idler shaft 24. In addition, the counter shaft 27
A counter gear 28 and a final reduction gear 29 are fixed to the forward gear 21 and the reverse idler gear 26 at the same time, and the final reduction gear 29 meshes with the ring gear 31 of the differential device 30 and transmits the power to the output shaft. 32.

The pressure regulating valve 40 regulates the hydraulic pressure discharged from the oil reservoir 41 by the oil pump 42, and supplies it as line pressure to the speed change control valve 43.
, is output to the load thrust control valve 45 and the start control valve 47. Each control valve 43, 45.47 operates a solenoid 44, 46.48 in response to a control signal (for example, a duty control signal) output from the electronic control device 60, regulates the line pressure, and operates the oil chamber 16.17 respectively. clutch 2'
Control hydraulic pressure is output to 0 and 0. Therefore, the gear ratio of the continuously variable transmission lO, the belt tension, and the torque transmission capacity of the starting clutch 20 can be freely controlled only by control signals input from the electronic control device 60 to the solenoids 44, 46, 48.

Note that the control valves 43, 45, 47 and °ζ may be configured, for example, by a combination of a solenoid valve that generates a signal hydraulic pressure and a spool valve that outputs a hydraulic pressure corresponding to the signal hydraulic pressure.
Alternatively, it may be composed of a single electromagnetic valve such as a solenoid valve. In any case, the solenoids 44, 46 .
It is sufficient if the oil pressure proportional to the signal input to 48 can be output.

FIG. 2 shows a structural diagram of the electronic control device 60, in which 61
is a sensor that detects the engine rotation speed N, 7 (the rotation speed of the input shaft 5), 62 is a sensor that detects the vehicle speed V (the rotation speed of the output shaft 32), and 63 is the rotation speed of the driven shaft 13 Noi+t
a sensor that detects (the input rotation speed of the starting clutch 20);
64 is a shift position sensor that detects each range or driving mode of P, R, N, D, L, 65 is a sensor that detects the throttle opening, and the signals from the sensors 61 to 64 are input to the input interface 66. , the signals from the sensor 65 are converted into digital signals by an A/D converter 67. 6
8 is a central processing unit (CPU), 69 is a read-only memory (ROM) that stores programs and data for controlling each solenoid 44, 46, and 48, and 70 is a memory that stores signals and parameters sent from each sensor. Random access memory (RAM) for temporary storage, 71 is an output interface, and these CPU U3O, ROM69
, RAM 70, output interface 71, manual interface 66, and A/D converter 67 are interconnected by a bus 72. The output of the output interface 71 is connected to the solenoid 44 via the output dry buffer 3.
, 46 and 48 as control signals.

FIG. 3 shows a block diagram of the gear ratio control system in the electronic control device 60.

In the drawing, the first target value determining means 80 is a means for determining the first target engine rotation speed Nyo, and determines the first target value according to a preset shift pattern based on the input throttle opening, vehicle speed, and range mode signal. The engine speed N3 is determined as shown by the broken line in FIG. Note that the target value is not limited to the target engine speed, but may be a target gear ratio.

The second target value determining means 81 includes a first target engine rotation speed N,
and vehicle speed V, maximum gear ratio (+1), minimum gear ratio (■,
), the second target engine speed Nll'' that can actually be reached is determined as follows. That is, the engine speed NL at the maximum gear ratio corresponding to the vehicle speed V (NL =
IL -V), the engine speed NN (NH-4,・V) at the minimum gear ratio corresponding to the vehicle speed v, then when NL <N, NII" = NtN>N
When l, N, ” = N.

When N, ≦Nm　≦NL, Nll"=N.

In other words, the second target engine speed N8'' is in the intermediate region (shift region) between the maximum gear ratio and the minimum gear ratio, as shown in FIG.
, the engine speed is equal to the first target engine speed N, and on the maximum speed ratio, the engine speed is NL corresponding to the maximum speed ratio, and on the minimum speed ratio, the engine speed is N8, which is equivalent to the minimum speed ratio. be.

The reference operation amount determination means 82 predicts the standard operation amount (duty ratio) in a steady state that can be reached from the engine torque and the gear ratio. Note that, since it is difficult to actually detect engine torque, it may be estimated based on an engine performance curve obtained in advance from actual measurement data, for example, from throttle opening and engine speed. Further, the gear ratio is determined by the ratio between the engine rotation speed and the vehicle speed.

At the addition point 83, the deviation between the first target engine rotation speed N determined by the first target value determination means 80 and the actual engine rotation speed N1 is determined, and at the addition point 84, the deviation between the first target engine rotation speed N determined by the first target value determination means 80 and the second target value determination means 81 is determined. The deviation between the second target engine speed N, 11 determined in step 1 and the actual engine speed NIfi is determined.

The PI operating means 85 includes a proportional unit 86 for gain and an integrator 87 for gain. The proportional device 86 has a function of outputting a signal proportional to the deviation between the first target engine rotation speed N and the actual engine rotation speed N in as shown in the following equation, and adjusting the gain.

D,"K-(NI N1-)...(1
) Also, the integrator 87 outputs a signal DI that integrates the deviation between the second target engine speed N1'' and the actual engine speed N i ll as shown in the following equation, and has a function of eliminating steady-state deviation.

Di = Kr S (NI ” NH,) dt
(2) In place of the PI operation means 85, a differentiator 88 may be added as a PID operation means as shown by the broken line in FIG. RPM N, and actual engine RPM N in
It has the function of increasing responsiveness by outputting a signal D4 that differentiates the deviation from .

The output signals R, D, of the PI operation means 85 are added together with the output signal D0 of the reference operation amount determining means 82 at a summing point 89, and the sum of the signals is the shift control valve which is the shift control actuator. 43 (Solenoid 44)
is input. The speed change control valve 43 supplies control oil pressure according to an input signal to the speed ratio control oil chamber 16 of the continuously variable transmission 10 to perform speed change control.

Next, the operation of the shift control system having the above configuration will be explained with reference to FIG.

When control starts, first the current engine speed,
Step 90) Input throttle opening, vehicle speed, mode/range signal, etc., and target engine rotation speed Nm according to these throttle opening/vehicle speed and mode/range signals.
92), then vehicle speed and maximum gear ratio (IL)
, and the minimum gear ratio (■,), calculate the maximum engine speed Nt and minimum engine speed NN that can be reached (
93).

Next, the target engine speed Nl and the maximum engine speed N
Compare t and minimum engine speed NH (94)
,Ne〉When NL, the second target engine rotation speed N. ′
Let Nt be 95), and when NI < N8, Nl"
When N++≦N1≦NL, let N and I be N8 (see 97).

After determining N and N, 1' as described above, the reference operation amount D0 is determined from the engine torque and gear ratio.
8) From the first target engine speed NIl and the actual engine speed N, calculate the proportional correction term by equation (1).99) The second target engine speed NR' and the actual engine speed. The integral correction term D1 is calculated from the rotational speed N I m by equation (2) (100), and the above-mentioned signals R, D, , Di are added (101), and this is applied to the speed change control valve 43. After outputting to the solenoid 44, it returns.

As mentioned above, the proportional device 86 of the PID operating means 85 is
Target engine speed N. The integrator 87 performs the correction based on the second target engine rotation speed N+t''.In other words, in the shift region, the first
Since the proportional correction and the integral correction are performed using the target engine speed N, it is possible to exhibit excellent followability to the target engine speed N.

Furthermore, in a region where the target engine speed N8 cannot be approached no matter how much speed change control is performed, that is, at the maximum or minimum speed ratio, no integral correction is actually performed to prevent overflow of the integral correction term. Therefore, when shifting from the maximum speed ratio or the minimum speed ratio to the speed change range, information before the transition is not reflected later, and overshoot of the engine speed with respect to the first target engine speed N can be eliminated.

Note that, like the integrator 87, the proportional device 86 may also be corrected based on the second target engine speed N, 1, but in this case, the speed change control actuator 43 is manually operated at the maximum or minimum speed ratio. Since the signal generated is a value determined only by the reference operation amount D0, the gears must be changed while always balancing the oil pressure, making it impossible to reliably maintain the maximum gear ratio or the minimum gear ratio. Therefore, by correcting the first target engine rotation speed Nm as a reference, the proportional device 86 makes the proportional correction value at the maximum gear ratio or the minimum gear ratio take a large value.
The movable sheave 12b of month 2 is pressed against the operation limit position setting stopper so that the maximum speed ratio or the minimum speed ratio can be reliably maintained.

It should be noted that the present invention is not limited to the V-belt type continuously variable transmission as in the above embodiment, but can be similarly applied to other continuously variable transmissions.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, only the integrating means of the PI or PID operating means corrects the deviation between the actual value and the second target value. The correction term is held constant and overflow can be avoided.

Therefore, when the next shift is made to the shift range, the information before the shift is not reflected after the shift, and overshoot of the engine speed can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a Held type continuously variable transmission to which the present invention is applied, Fig. 2 is a structural diagram of the electronic control unit, Fig. 3 is a block diagram of the speed change control system of the electronic control unit, and Fig. 4 is a shift diagram showing the first target value and the second target value, FIG. 5 is a flow chart diagram showing the operation of the shift control device of the present invention, and FIG. 6 is a shift diagram showing the conventional operation. 1... Engine, 10... Continuously variable transmission, 16...
- Oil chamber for gear ratio control, 43... Gear shift control valve (actuator for gear shift control), 44... Solenoid, 60...
- Electronic control device, 80... first target value determining means, 81
... second target value determining means, 85...P [operating means,
86...Proportionalizer, 87...Integrator. Figure 6 Figure 1 Figure 2 Figure 3 Figure 4 Vehicle speed Figure 5

Claims (1)

[Claims] Deviation from the target value of engine speed or gear ratio P
In a shift control device for a continuously variable transmission that corrects by I or PID operating means and controls a shift control actuator according to the correction value, first target value determining means determines a first target value according to operating conditions. and second target value determining means for determining an attainable second target value by comparing the first target value and the shift control area, and the PI or PID operating means except for the integrating means determines the actual engine rotation speed. Alternatively, a speed change control device for a continuously variable transmission, wherein the deviation between the speed ratio and the first target value is corrected, and the integrating means corrects the deviation between the actual engine speed or the speed ratio and the second target value. .