JPH04321873A - Controller of automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To provide a speed change controller capable of safely driving and stopping a vehicle under the abnormal condition of an input pulley rotation sensor without affecting the life of a belt. CONSTITUTION:A continuously variable transmission 3 is subjected to speed change control under the abnormal condition of an input pulley rotation sensor 7 by substituting the output information 23 of an engine rotation sensor 6. The speed change control not accompanied by an abrupt change in the change- over of the sensor output information can be continued so that the safety of a vehicle under the abnormal condition of the input pulley rotation sensor is ensured without shortening the life of a belt.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is used in automatic transmissions for vehicles, particularly continuously variable transmissions and shift control devices, to enable the vehicle to run safely even when a sensor fails, and to stop the vehicle safely. The present invention relates to a speed change control method that achieves this.

0002

[Prior Art] Conventionally, as for the speed change control method of a transmission, we have proposed, for example, in Japanese Patent Laid-Open No. 63-57953, etc. Find the ratio and control the gear ratio so that it matches the target gear ratio determined from the vehicle state quantities stored in advance in the control device, or control the input rotation speed so that it matches the target input rotation speed It is done by doing. In other words, the input pulley rotation speed is an important factor in the speed change control, so it is conceivable to use a dual input pulley rotation sensor, for example.

[0003] Also, in Japanese Patent Application Laid-Open No. 62-244724,
Two systems of control methods are used for speed change control, and the total value is used as the speed change actuator command value for speed change control. That is, a feedforward loop calculates a target gear ratio from a target input pulley rotation speed determined from the vehicle running state quantity, and calculates a shift actuator command value from the target gear ratio, the target input pulley rotation speed, and the actual input. Shift control is performed using the total value of the feedback loop that calculates the command value as the shift actuator command value by proportional/integral calculations using the difference in pulley rotation speed as a deviation.

In order to solve the adverse effect on control when the input pulley rotation sensor fails, among the feedforward loop and feedback loop used for gear ratio control, when the input rotation sensor is abnormal, the feedback loop is stopped and the feed Speed change control is performed only in the forward loop, eliminating the influence of input pulley rotation sensor failure on the feedback loop.

[0005]

[Problem to be solved by the invention] In the above-mentioned prior art 1,
Since hardware means such as duplicating the input pulley rotation sensor are used, there are problems with mounting arrangement and cost increase due to duplication of the input pulley rotation sensor signal input circuit.

In addition, in the above-mentioned prior art 2, in consideration of the adverse effect on the feedback loop when the input pulley rotation sensor is abnormal, the shift control is switched to only the feedforward loop, so that the delay of the shift hydraulic actuator system during shift transitions etc. , if there is a large deviation between the target input pulley rotation speed and the actual input pulley rotation speed, the feedback loop will stop.
This poses a problem in that there is a risk of sudden downshifting, which is undesirable from the viewpoint of vehicle safety and the life of the V-shaped belt.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for solving the above-mentioned problems such as increased costs due to hardware duplication, and a speed change that allows a vehicle to run and stop safely even when the input pulley rotation sensor is abnormal. The objective is to provide a control method.

[0008]

[Means for Solving the Problems] In order to achieve the above object, when the input pulley rotation sensor is abnormal, an engine rotation speed signal is substituted for the input pulley rotation speed to continue speed change control.

Furthermore, when the vehicle is restarted after it has been stopped, the access opening degree is fixed to be higher than the actual accelerator opening degree, and the speed change control is performed.

0010

[Operation] According to the above means, when the input pulley rotation sensor is abnormal, the input pulley rotation speed is changed to the engine rotation speed signal, thereby locking the power transmission device from the engine, that is, the fluid coupling, the torque converter, etc. In the up state, the rotation speeds of both sides are almost equal, so even if the input pulley rotation speed is changed to the engine rotation speed when the input pulley rotation sensor is abnormal, there will be no sudden change in gear shifting, so the speed will remain as it is. Therefore, it is possible to continue the speed change control at the input pulley rotation sensor, and it is possible to solve the problem of the above-mentioned loss of vehicle safety due to abnormality of the input pulley rotation sensor and the problem of the lifespan of the V-shaped belt.

[0011]

Embodiments Examples of the present invention will be described below with reference to FIGS. 1 to 7.

FIG. 1 shows the configuration of this embodiment.

[0013] The engine 1 is used as a power source, and this driving force is
In a vehicle that is driven by transmitting information to drive wheels 4 through a fluid coupling, a torque converter 2, and a hydraulically driven belt-type continuously variable transmission 3, from a throttle sensor 5 that indicates the accelerator opening, which is a driving operation amount. output throttle opening information 22, information measured by various sensors that are driving state quantities of the vehicle, that is, engine rotation speed information 23 from the engine rotation sensor 6, and rotation speed of the input side pulley 18 of the continuously variable transmission 3. Based on the input rotation speed information 24 from the input rotation sensor 7, which is information, and the vehicle speed information 25 from the vehicle speed sensor 8, which is also the rotation speed information of the output pulley 19, the microcomputer 9 sends the information to the speed change actuator (for example, a step motor) 10. Calculate the control command value 26 and the change amount of the control parameter used for the operation command value 26, output to the step motor 10, and change the control parameter of the operation command calculation unit to the step motor 10 according to the change amount. Make changes.

The step motor 10 controls the gear ratio of the continuously variable transmission 3 based on the operation command value 26 calculated by the microcomputer 9.

The mechanism using the step motor 10 is a known mechanism similar to that disclosed in Japanese Patent Laid-Open No. 59-47553.

The step motor 10 moves the speed change control valve 13 by using the actuator 11 and the valve stem 12, and inserts high pressure oil into the movable pulley half 20 of the input pulley of the continuously variable transmission 3. This reduces the gear ratio (toward the top), which is represented by the ratio of the rotation speed of the input pulley 18 to the rotation speed of the output pulley 19, and also reduces the movable pulley half 20 of the input pulley.
By returning oil to the reservoir 16, it is possible to increase the gear ratio (lower direction).

One end of the valve stem 12 is in contact with the inner conical surface of the movable pulley half 20 of the input pulley, and the other end of the valve stem 12 is in contact with the shaft 21 of the actuator 11. There is. In the continuously variable transmission 3, driving torque input from the engine through the torque converter 2 is transmitted to the input pulley 18, the metal belt 17, and the output pulley 19 in this order.

An outline of a flowchart of the control processing procedure by the microcomputer 9 is also shown in FIG. The control method in this embodiment will be described as a method in which control is performed using fuzzy rules.

In measurement data reading processing block 101, throttle opening information 22, vehicle speed information 25, and input pulley rotation speed information 24 are read, and the process moves to block 102. In block 102, a target input rotation speed calculation process is performed. That is, the target input pulley rotation speed N is calculated from the throttle opening information 22 and the vehicle speed information 25, but in order to calculate the target input pulley rotation speed N, the target input pulley rotation speed N and vehicle speed v shown in FIG. , throttle opening θ relationship curve data are stored in advance in the read-only memory of the microcomputer 9, and using these data, the target input pulley rotation speed N at any vehicle speed and throttle opening is determined by linear interpolation. Calculate. Then, the difference e (hereinafter referred to as deviation) between the target input pulley rotation speed N obtained in the target input pulley rotation speed calculation processing block 102 and the actual input pulley rotation speed Nin is determined, and the process proceeds to block 103.

In the target step motor position difference calculation processing block 103, the target step motor position difference is calculated using, for example, the following fuzzy rule.

(Fuzzy Rule 1) e is negative and small, and
When Δe (e of current time - e of 10ms ago) is negative and small,
Move the step motor a moderate amount in the direction of increasing the gear ratio.

(Fuzzy Rule 2) e is positive and small, and
When Δe is positive and small, move the step motor by a medium amount in the direction of decreasing the gear ratio.

(Fuzzy Rule 3) e is zero and Δe
When is zero, fix the step motor.

Based on the above three fuzzy rules, the target step motor position difference ΔI is determined.

This is based on the above fuzzy rule 1 shown in FIG.
3 membership functions SNE, SNDE, SPE
, SPDE, ZRE, ZRDE at e and Δe from the equation shown below, the fitness degree yi, (i=1, 2, 3
).

[0026]

[Math 1]

Next, the target step motor position difference ΔI is determined based on the degree of conformity of each of the above rules using the formula shown below, and the process proceeds to block 104.

[0028]

[Math 2]

In the above equation, Gi represents the center of gravity of each rule, and Si represents the area of each rule. (However, i = 1, 2, 3.) Here, the goodness of fit for the membership function means that the membership function is the vertical axis value (0 to 1) for the horizontal axis variable.
It is the ordinate value that corresponds to the abscissa value when considered as a mapping function that corresponds to

FIG. 3 shows membership functions N1, Z1, P
1, and the abscissa indicates the change in the number of steps of the step motor.

FIG. 4(A) shows the membership functions SNE,
ZRE, SPE are shown, and the abscissa is the deviation e (rpm
). Figure 4(B) shows the membership function SNDE
, ZRDE, and SPDE, and the abscissa is the deviation difference Δe (rpm).

[0032] Once the target step motor position difference ΔI has been determined based on the fuzzy rule, the process then proceeds to operation amount calculation processing block 104 based on this ΔI.

In operation amount calculation processing block 104, block 1 is calculated for the current target step motor position command value I.
The value obtained by adding ΔI obtained in step 03 is replaced with the target step motor position command value I. In other words, it is as follows.

[0034]

[Math 3]

The magnitude of I is output in the manipulated variable output processing in block 105 and is used as a command value for the step motor.

To summarize these series of processes, the target input pulley rotation speed N is calculated from the throttle opening degree information 22 and the vehicle speed information 25, and the actual input pulley rotation speed information 24 is used as the input information of the feedback loop to change the speed. Take control.

At this time, it is clear that if the actual input pulley rotation speed information 24 suddenly becomes zero due to a failure of the input pulley rotation sensor 7, the above-mentioned feedback loop will no longer be established and control will become uncontrollable. be.

Therefore, in the present invention, when the fluid coupling or torque converter 2 is locked up while the vehicle is running, the input pulley rotation speed is equal to the engine rotation speed, and when the input pulley rotation sensor fails, the input pulley rotation speed is By using the engine rotation speed information 23 instead of the pulley rotation speed information 24, uncontrollability can be avoided.

FIG. 5 is a control flowchart showing the part of the control that is performed by replacing the input pulley rotation sensor information 24 with the engine rotation sensor information 23 when the input pulley rotation sensor fails, which is the subject of the present invention.

Blocks 201 and 202 are blocks for determining whether the input pulley rotation sensor is normal or abnormal.

If the input pulley rotation speed is zero while the vehicle is running (vehicle speed is not zero), it is determined that the input pulley rotation sensor is abnormal. This is because when the output signal of the input pulley rotation sensor is normal, it is output as a pulse signal, and when the input pulley rotation sensor is malfunctioning, the sensor output becomes electrically constant at a "high level" or "low level". Therefore, when the signal is input into the microcomputer 9, the pulse-like output is not fixed at a "high level" or "low level" and the input pulley rotation speed is considered to be zero.

If the input pulley rotation sensor is determined to be abnormal here, the process proceeds to input pulley rotation speed abnormality processing 203.

The input pulley rotation speed sensor abnormality processing block 203 basically performs two things as shown below.

One of them is to set the input pulley rotation sensor abnormality flag to 1. The second is to replace the speed change control, which previously used the input pulley rotation speed, with the engine rotation speed.

Next, if the vehicle speed is zero, block 2
In step 04, it is determined whether the input pulley rotation sensor has been abnormal until now. This determination is made using the abnormality flag in the input pulley rotation sensor abnormality processing block 203. If the abnormality flag is 1, block 20
Proceed to step 5.

In the start processing block 205 when the input pulley rotation sensor is abnormal, a throttle opening value is set so that the throttle opening is fixed at, for example, a fully open value for subsequent speed change control. This is because, as shown in Fig. 6, when viewed from the set value of the target input pulley rotation speed, the time during which the gear ratio remains at the maximum value (low gear) is long, and the time when the vehicle is in a non-lockup state when starting the vehicle is This is because it can be kept at maximum.

This is to compensate for the fact that the input pulley rotation speed does not match the engine rotation speed when there is no lockup (non-lockup state). As shown in Figure 7, the transition from non-lockup to lockup state is determined from the relationship between vehicle speed and throttle opening, and lockup is set to begin at a vehicle speed of approximately 15 km/h. Therefore, when you step on the accelerator when starting, the engine speed increases too much, so it exceeds the target input pulley rotation speed, and if you control the gear ratio while comparing the engine speed with the target input pulley rotation speed, the engine speed will be faster than the actual speed. This is because the vehicle will be shifted up.

[0048]

[Effects of the Invention] According to the present invention, there are the following effects.

When the input pulley rotation sensor is abnormal, by changing the input pulley rotation speed to the engine rotation speed signal, the power transmission device from the engine, that is, the fluid coupling,
Or, when the torque converter etc. is locked up, both rotation speeds are the same, so even if the input pulley rotation speed is changed to the engine rotation speed when the input pulley rotation sensor is abnormal, there will be no sudden change in gear shifting. Therefore, it is possible to continue the speed change control in the same state, and it is possible to solve the problem of the above-mentioned loss of vehicle safety due to abnormality of the input pulley rotation sensor and the problem of the lifespan of the V-shaped belt.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a curve diagram for deriving the target input pulley rotation speed in an embodiment of the present invention.

FIG. 3 is a diagram showing membership functions in this embodiment.

FIG. 4 is a diagram showing membership functions in this embodiment.

FIG. 5 is a flowchart showing a control method of the present invention.

FIG. 6 is a curve diagram for deriving the target input pulley rotation speed used for speed ratio control in the present invention.

FIG. 7 is a lock-up vehicle speed derivation curve diagram in this embodiment.

[Explanation of symbols]

3... Continuously variable transmission, 5... Throttle sensor, 6... Engine rotation sensor, 7... Input pulley rotation sensor, 8... Vehicle speed sensor, 9... Microcomputer, 10... Step motor.

Claims (5)

[Claims] Claim 1: A control device detects vehicle conditions such as engine rotation speed, input pulley rotation speed, and vehicle speed, calculates a command value according to the condition, outputs a command based on the calculated value, and outputs a command value to the input pulley. In a control device for a vehicle automatic transmission that changes the interval between the V-shaped grooves of the output pulley and the effective diameter of both pulleys to steplessly change gears, when the input pulley rotation sensor is abnormal, the engine speed is changed. A control device for an automatic transmission for a vehicle, characterized in that it performs gear change control by replacing input rotation speed. 2. The automatic speed change for a vehicle according to claim 1, wherein when the input pulley rotation sensor is abnormal, the speed change control after the vehicle has stopped is performed by changing the accelerator opening. Machine control device. 3. The control device for an automatic transmission for a vehicle according to claim 1, wherein the shift control is performed by a feedback loop using input pulley rotation speed as input information. 4. The control device for an automatic transmission for a vehicle according to claim 1, characterized in that a fuzzy rule is used particularly in a shift control algorithm. 5. A control device for an automatic transmission for a vehicle according to claim 2, characterized in that the accelerator opening degree after the vehicle has stopped is replaced with an accelerator fully open value to perform gear change control.