JP2003307272A - Control device of continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of matching processes of a speed-change schedule map, to reduce a total development time, and to enable fine speed-change control according to the state of a vehicle for a continuously variable transmission having a torque converter on the side of an engine. <P>SOLUTION: A memory for storing an engine characteristic and a torque converter characteristic is provided, transmission input torque is obtained according to the state of the torque converter based on engine torque or an engine revolution speed sensor output, transmission input shaft revolution number sensor output and the torque converter characteristic, and the continuously variable transmission is controlled so that a target speed-change ratio obtained from the transmission input torque and target driving shaft torque is obtained. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a continuously variable transmission, and more particularly to a control device for a V-belt continuously variable transmission.

[0002]

2. Description of the Related Art For example, as a shift control method for a V-belt type continuously variable transmission, there is one disclosed in Japanese Patent Laid-Open No. 4-321873. In this shift control, normally, a target input pulley rotation speed is calculated from an engine load state detection signal such as a throttle sensor and a vehicle speed signal, and a transmission is operated by an actuator so that a gear ratio corresponding to the target value is obtained. Is.

Here, in order to calculate the target input pulley rotation speed, it is general to use a shift schedule map held in the memory of the electronic control unit, but it may be calculated. .

Here, when the range position represented by a running pattern such as a normal range or a sporty range changes, it is common to change the shift schedule map. There was no choice but to shift using the schedule map for the normal range, and also for the sporty range, similarly using a predetermined schedule map.

[0005]

The above schedule map is a shift schedule which is integrally set by an automobile manufacturer and a transmission maker from a comprehensive aspect of fuel consumption characteristics, acceleration characteristics, and the like. In the case of coping with the shift of the shift control amount resulting from the change and changing the shift schedule according to the preference and driving situation of each user of the vehicle, that is, the acceleration characteristic, the engine braking characteristic, etc., this has not been taken into consideration in the prior art.

Further, in the case of development by the above-mentioned maker, it takes a lot of time to decide the shift schedule map, and the reduction of this time occupies a weight enough to reduce the total development time.

Therefore, the problem to be solved by the present invention from the above-mentioned conventional example is to provide vehicle characteristics such as engine characteristics and torque converter characteristics to reduce the matching man-hours of the shift schedule map and shorten the total development time. An object of the present invention is to provide an automatic transmission capable of performing fine shift control according to a vehicle state.

[0008]

In order to achieve the above object, the engine torque is estimated from the vehicle parameters, that is, the engine speed, the accelerator opening, and other parameters indicating the engine load, and the transmission input torque is calculated. The target speed ratio is calculated by calculating the ratio between the calculated transmission input torque and the target drive shaft torque obtained from the parameter indicating the engine load, and the target speed ratio is calculated using this target speed ratio. By performing control, the above object can be achieved.

According to the above, it is possible to perform a shift that matches the vehicle situation without using the shift schedule map of the transmission, and it takes a lot of time to tune the conventional shift schedule map. Is reduced to.

Further, by carrying out the shift control according to the drive shaft torque, it becomes possible to easily set the fuel consumption-oriented type and the power performance-oriented traveling.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the accompanying drawings showing an embodiment thereof.

FIG. 1 shows the overall configuration of the present invention.

The torque generated from the engine 1 is a torque that can be directly coupled (this is called a lock-up function).
It is input to the drive pulley 3 of the V-belt type continuously variable transmission via the converter 2. The torque input to the drive pulley 3 is transmitted to the driven pulley 5 via the V belt 4.

One of the drive pulley 3 and the driven pulley 5 is fixed, and the other is made to change its position in the direction of the rotation axis by the hydraulic action. As a result, the gap between the pulleys is changed, which in turn changes the running diameter of the V-belt to perform the gear shifting action. The torque transmitted to the driven pulley 5 by the speed change action enters the final reduction gear 6 and is finally transmitted to the drive wheels 7.

On the other hand, to describe the path of the hydraulic system, the oil suctioned by the pump 11 from the oil sump 9 through the oil filter 10 is discharged to the oil passage 8.
The oil pressure in the oil passage 8 is generally called line pressure, and is regulated by the line pressure control valve 12 and serves as a basic pressure for gear shifting operation.

The line pressure control valve 12 receives an instruction pressure calculated in the continuously variable transmission control device 15 having a built-in microcomputer through the electric path 16 and performs electromagnetic-hydraulic conversion to control the line pressure. It is a proportional control valve.

The line pressure is introduced into the driven pulley cylinder oil chamber 5a through the oil passage 8, is appropriately reduced in pressure through the speed change control valve 13, and is also introduced into the drive pulley cylinder oil chamber 3a through the oil passage 14.

Like the line pressure control valve 12, the speed change control valve 13 receives a signal from the continuously variable transmission control device 15 through the electric path 17 and performs electromagnetic-hydraulic conversion to perform an oil passage 14.
It is an electromagnetic proportional control valve that controls the hydraulic pressure of.

It should be noted here that the signal flowing through the electric path 17 indicates the absolute hydraulic pressure of the oil path 14,
This means that the ratio of the hydraulic pressure of 4 to the line pressure (the hydraulic pressure of the oil passage 8) is not designated. Further, even if the indicated value becomes larger than the line pressure, the upper limit of the pressure in the drive pulley cylinder oil chamber is limited by the line pressure. Therefore, the oil pressure of the oil passage 14 is never controlled to be higher than the line pressure.

In consideration of this, the axial pressure receiving area of the drive pulley cylinder oil chamber 3a is determined by the driven pulley cylinder oil chamber 5
It is set almost twice as large as that of a. Accordingly, the belt pressing pressure of the drive pulley can be controlled to a range exceeding the pressing pressure of the driven pulley, and an arbitrary pressing pressure ratio (ratio between the driving pulley pressing pressure and the driven pulley pressing pressure) can be realized. Therefore, the high speed ratio (Low side) to the low speed ratio (High side) can be operated only by the line pressure control valve 12 and the speed change control valve 14.

The drive pulley rotation speed sensor 18 transmits the rotation speed of the drive pulley 3 to the continuously variable transmission control device 15 as an electric signal. This may be substituted by the engine rotation speed sensor 20 if the direct / non-direct connection information of the torque converter 2 and the rotational speed ratio of the pump and the turbine are known.

The driven pulley rotation speed sensor 19 also transmits the rotation speed of the driven pulley 5 to the continuously variable transmission control device 15 as an electric signal. The driven pulley rotation speed sensor 19 need not detect the rotation speed of the driven pulley 5 directly, but may detect the rotation speed of the drive shaft of the vehicle and the final reduction gear (that is, vehicle speed). good.

The continuously variable transmission control device 15 can calculate the actual gear ratio by taking the ratio of the rotational speeds of the driving pulley and the driven pulley.

The engine speed sensor 20 and the throttle sensor 21 give signals necessary for estimating the engine generated torque. The engine rotation sensor 20 may use the crank angle signal or the ignition timing signal of the engine control device. Further, the throttle sensor 21 may be a sensor that captures the intake pipe negative pressure of the engine or the mass air flow rate.

Next, a control block diagram showing a control method inside the continuously variable transmission control device 15 is shown in FIG.

The engine rotational speed data from the engine rotational speed sensor 20 and the accelerator opening data from the throttle sensor 21 are fetched into an engine torque calculating portion 31. The engine torque calculating portion 31 is an engine of the vehicle shown in FIG. It is possible to estimate the engine torque Te of the vehicle at that time by preliminarily storing the characteristics in the memory and taking the engine speed as the horizontal axis and the accelerator opening as the parameter.

Next, the obtained engine torque Te is
In the present embodiment, in order to use the torque converter, 4
At 5, it is determined whether the lockup is in progress. If the lockup is in progress, the transmission input torque is obtained by multiplying the constant 1 by 32. If the lockup is not being performed, the torque ratio obtained by the torque converter characteristic calculating unit 33 is multiplied by the engine torque at 41 to obtain the transmission input torque. Here, the torque converter characteristic calculation unit 33 stores the data from the engine rotation speed sensor 20 and the data from the input rotation sensor 18 into 40
The speed ratio e, which is the ratio of the input side rotational speed and the output side rotational speed of the torque converter, is obtained by dividing by, and the torque ratio is calculated from the torque converter characteristic shown in FIG.

Next, using the target drive shaft torque characteristic 34 with respect to the speed in which the parameter stored in advance in the memory shown in FIG. 5 is the accelerator opening degree, the data from the vehicle speed sensor 19 and the accelerator from the throttle sensor 21 are used. The target drive shaft torque is obtained by inputting the opening degree data to the block 34, and the estimated transmission input torque obtained previously and the target drive shaft torque obtained at the block 34 are divided by 42 to obtain 3
The target gear ratio, that is, the gear ratio command value of the transmission is obtained by dividing by the final reduction ratio of 5, and multiplying by the constant K1 of 36.

As described above, using the target drive shaft torque as shown in FIG. 5 leads to the pursuit of an ideal drive torque with respect to the vehicle speed, and the shift control can be performed with an emphasis on pursuing the power performance of the vehicle. Become.

That is, in the embodiment of the present invention, the control using one target drive torque map is described for the sake of simplicity. However, normally, the fuel economy-oriented economy mode and the power performance-oriented power are used. It is advisable to set the map to be switched depending on the use such as the mode.

Further, the difference between the modes may be automatically switched depending on, for example, the amount of change in the accelerator opening.

Here, the data from the transmission input rotation speed sensor 18 and the vehicle speed data from the vehicle speed sensor 19 are
Since the actual current gear ratio can be obtained by multiplying by 37 and the constant K2 multiplied by 37, the difference between the target gear ratio obtained previously and the actual gear ratio can be obtained at 43 to obtain the target gear ratio. The deviation of can be calculated. The actuator operation amount calculation unit 38 calculates the actuator operation amount based on the gear ratio deviation, and the actuator drive signal generation unit 39 converts the operation amount into a signal for actually driving the actuator to drive the actuator 13.

Now, as shown in FIG. 6, for example, the actuator operating section of the block 38 executes the proportional calculation 50 and the integral calculation 51 with respect to the preceding gear ratio deviation, and obtains the sum 53 of the respective results. It is possible to obtain the operation amount of the actuator.

In another embodiment shown in FIG. 9, the manipulated variable can be obtained by fuzzy inference based on the deviation instead of the proportional and integral operations of FIG.

Next, as another embodiment, the case where the electromagnetic clutch shown in FIG. 7 is used instead of the torque converter will be described. The electromagnetic clutch control method is generally shown in FIG.
As shown in Fig. 5, the excitation current is increased as the engine speed increases and the transmission torque is increased.However, in the case of an electromagnetic clutch, unlike torque converters, there is no torque doubling force, so the torque transmitted in the completely engaged state is Almost 1 for torque
Therefore, the result t of 33 in the block diagram of FIG. 2 is apparently t <1 and the torque is more disadvantageous when the vehicle is in a non-lockup state such as when starting than when using the torque converter.

In another embodiment, the fuel efficiency curve shown in FIG. 8 is stored in advance in the memory in the method for obtaining the drive shaft torque shown in 34 in the block diagram of FIG. By calculating the used torque, it becomes possible to perform gear shift control with an emphasis on fuel consumption.

As another embodiment, the block 34 of FIG.
Can be given as a function indicating the drive shaft torque without depending on the above two types of maps, and the target drive shaft torque can be obtained by constantly calculating based on the state of the vehicle.

The throttle sensor data of the input signal 21 of FIG. 2 may be any signal as long as it represents the load state of the engine, and is, for example, a parameter for determining the intake air amount data of the engine or the fuel injection force. It may be fuel injection time data.

[0039]

As described above, according to the present invention, particularly in the shift control of the vehicle equipped with the continuously variable transmission,
By modeling the information related to the vehicle such as engine characteristics and torque converter characteristics and making it on-board, it is possible to reduce the matching man-hours such as the shift schedule of the transmission, and the shift control such as fuel efficiency-oriented and power performance-oriented. It becomes possible finely.

[Brief description of drawings]

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

FIG. 2 is a control configuration diagram showing an embodiment of the present invention.

FIG. 3 is a diagram showing an example of engine characteristics.

FIG. 4 is a diagram showing an example of torque converter characteristics.

FIG. 5 is a diagram showing an example of a characteristic of a drive shaft torque with respect to a vehicle speed.

FIG. 6 is a control configuration diagram of a proportional-integral type gear ratio control.

FIG. 7 is a diagram showing an example of electromagnetic clutch characteristics.

FIG. 8 is a diagram showing an example of a fuel consumption curve.

FIG. 9 is a control configuration diagram of fuzzy gear ratio control.

[Explanation of symbols]

1 ... Engine, 2 ... Torque converter, 3 ... Drive pulley, 3a ... Drive pulley cylinder oil chamber, 4 ... V belt, 5
... driven pulley, 5a ... driven pulley cylinder oil chamber, 6 ... final reducer, 7 ... drive wheel, 8 ... line pressure oil passage, 9 ... oil sump, 10 ... oil filter, 11 ... oil pump, 12 ... Line pressure control valve, 13 ... Shift control valve, 14
... oil passage to drive pulley, 15 ... continuously variable transmission control device,
18 ... Drive pulley rotation speed sensor, 19 ... Driven pulley rotation speed sensor, 20 ... Engine rotation speed sensor, 21 ...
Throttle sensor.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16H 59:24 F16H 59:24 59:42 59:42 59:44 59:44 63:06 63:06 ( 72) Inventor Masahiko Hashimoto 2520 Takaba, Katsuta-shi, Ibaraki, Hitachi, Ltd., Automotive Equipment Division, Hitachi, Ltd. (72) Inventor Hiroshi Kuroiwa 2520, Takaba, Katsuta, Ibaraki, Ltd. F-Term, Automotive Equipment Division, Hitachi, Ltd. (Reference) 3J552 MA07 MA12 NA01 NB01 PA31 PA52 PA64 RA02 SB02 SB21 VA32W VA42W VA74W VC01W VC02W VC03W

Claims (2)

[Claims] 1. A control device for a continuously variable transmission having a torque converter on the engine side, comprising a memory for storing engine characteristics and torque converter characteristics, wherein an actual gear ratio is calculated from an engine rotation speed sensor output and a vehicle speed sensor output. The engine torque is calculated from the engine speed sensor output, the throttle sensor output, and the engine characteristic, and the engine torque is calculated based on the engine torque, or the engine torque, depending on the state of the torque converter. The transmission input torque is obtained based on the shaft speed sensor output and the torque converter characteristic, the target drive shaft torque is obtained from the vehicle speed sensor output and the throttle sensor output, and the target is obtained from the transmission input torque and the target drive shaft torque. Calculate the gear ratio and achieve the target gear ratio. A control device for a continuously variable transmission that controls the continuously variable transmission. 2. The control device for a continuously variable transmission according to claim 1, wherein the torque converter characteristic is a torque ratio.