JPH11159605A - Control device of automatic transmission and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent shift characteristic by accurately controlling working oil pressure of a clutch, by generating a shift starting signal of an automatic transmission, prestoring information on a friction coefficient related to a speed shift, and deciding a pressure adjusting command value by an operation on the basis of frictional information storage after generating the signal. SOLUTION: An engine torque operation means 32 in a control controller 31 outputs a control signal to an electronic control throttle 5, a fuel injector 6 and an igniter 2. An operation is performed on the gear ratio of a transmission 19 by inputting an input shaft rotating speed Nt and an output shaft rotating speed No to a rotational ratio operation means 33 in the control controller 31. An operation is performed on input shaft torque of the transmission 19 by inputting an engine speed Ne, a torque converter characteristic stored in a torque converter characteristic storage means and the engine side inertia moment stored in a correction constant storage means to an input shaft torque operation means 36. Therefore, an excellent characteristic can be obtained by feedforward control of operating pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling a hydraulic pressure at the time of shifting in an automatic transmission of a motor vehicle, and more particularly to a device for electrically controlling a hydraulic pressure applied to a clutch (friction engaging device) to release or release a clutch. The present invention relates to a control device for performing engagement and a method thereof.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No. Sho 63-26 discloses a known example in which the clutch operating hydraulic pressure is electrically controlled to release and engage the clutch.
There is one described in Japanese Patent No. 3248. In this publication, when controlling the working oil pressure of the on-coming clutch at the time of upshifting and the disengagement clutch at the time of downshifting, the input shaft speed (turbine speed) of the transmission is used. A method of controlling so as to follow a preset target value of the input shaft rotation speed is described. According to the present invention, a change in the number of revolutions during a shift caused by a change in the friction coefficient of the clutch unit is detected, and this is fed back to be reflected in the hydraulic control. Thus, it is proposed that clutch oil pressure control during stable shifting can be performed.

[0003]

According to the known example,
Since the working oil pressure of the clutch is controlled by the transmission input shaft rotation speed feedback, if the friction coefficient of the clutch changes greatly between the clutch input / output shaft rotation difference and each clutch, the feedback cannot cope with the clutch and the transmission performance deteriorates. There is a problem of doing so. Therefore, an increase in shift shock due to the rotation difference and a change in friction coefficient for each clutch cannot be avoided.

SUMMARY OF THE INVENTION It is an object of the present invention to accurately control the working oil pressure of the clutch to obtain good shift characteristics even when the rotational difference and the friction coefficient for each clutch greatly change.

[0005]

In order to reduce the size and weight of the automatic transmission and to improve the control performance, the one-way clutch is eliminated, and the clutch operation is disengaged and engaged by directly controlling the clutch hydraulic pressure electrically. The establishment of a transmission control system is becoming important. In the above system, it is essential to accurately control the hydraulic pressure acting on the clutch to suppress torque fluctuations (shock) during shifting. However, in an actual vehicle, a machine difference between transmissions due to mass production, a change in clutch wear coefficient due to aging, and a change in wear coefficient due to a clutch input / output shaft rotation difference occur. This is a cause of the torque fluctuation. It has become. Therefore, it has been proposed to detect a change state of the clutch hydraulic pressure using some kind of sensor signal, and to perform feedback control based on the detection result. However, when the change in the friction coefficient is considerably large, there is a problem that the feedback cannot cope with the change and the shift performance deteriorates. Therefore, an increase in shift shock due to the rotation difference and a change in friction coefficient for each clutch cannot be avoided.

[0006] In order to solve the above problems, the following problems are specifically solved by the following apparatus. That is, the present invention performs a shift by engaging or disengaging at least one friction engagement device in an automatic transmission connected to an engine, and reduces a hydraulic pressure acting on the friction engagement device during the shift. In a hydraulic control apparatus for an automatic transmission, comprising a pressure adjustment command calculating means capable of adjusting the pressure and changing the pressure adjustment characteristic, a shift command signal generating means for generating a shift start signal of the automatic transmission; Frictional information storage means for preliminarily storing information on a friction coefficient of the frictional engagement device concerned, wherein a pressure adjustment calculated by the pressure adjustment command calculation means after a signal is generated from the signal generation means. An apparatus is provided in which a command value is determined based on information in the friction information storage means.

[0007] Preferably, the pressure regulation command calculating means is provided with a delay compensating means for compensating for a delay in a hydraulic system of the transmission.

Preferably, the friction information stored in the friction information storage means is changed at least in accordance with a change in a transmission input shaft speed.

Preferably, there is provided friction information detecting means for detecting the friction information of the friction engagement device, and friction information rewriting means for rewriting the friction information stored in the friction information storage means based on the detection result.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. FIG. 2 is a detailed block diagram of the present invention. In FIG. 1, an engine 1 is a four-cylinder engine in this embodiment. The engine 1 is provided with an ignition device 2. The ignition device 2 has four ignition plugs 3 corresponding to the number of cylinders of the engine 1. An intake pipe 4 for taking air into the engine 1 is provided with an electronic control throttle 5 for adjusting a flow rate of air passing therethrough, a fuel injection device 6 for injecting fuel, and an air flow meter 7. The fuel injection device 6 has four fuel injection valves 8 corresponding to the number of cylinders of the engine 1. Further, the injection valve 8 may be directly blown into a cylinder (not shown) in the engine 1. The electronically controlled throttle 5 is the throttle valve 1
0 is driven to control the air flow rate. In a normal automobile, the throttle valve 10 and an accelerator pedal (not shown) are connected by a mechanical wire (not shown), and operate one-to-one.

A flywheel 12 is attached to a crankshaft 11 of the engine 1. Flywheel 12
Is provided with an engine speed sensor 13 for detecting the speed of the crankshaft 11, that is, the engine speed Ne. The torque converter 14 directly connected to the flywheel 12 includes a pump 15, a turbine 16, and a stator 17. The output shaft of the turbine 16, that is, the input shaft 18 of the transmission, is directly connected to the stepped transmission 19. Here, two friction engagement devices 22,
A description will be given of a so-called clutch-to-clutch transmission 19 in which a shift is executed by engaging and disengaging 23. A transmission input shaft rotation speed sensor 20 for measuring a transmission input shaft rotation speed (turbine rotation speed) Nt is attached to the transmission input shaft 18. The transmission 19 includes a planetary gear 21 and clutches 22 and 23. The gear 21 is engaged and disengaged by engaging and disengaging the clutches 22 and 23.
Is changed and the gear ratio is changed. These clutches 22 and 23 are controlled by spool valves 26 and 27 and linear solenoids 28 and 29 (pressure adjusting devices), respectively. Further, the transmission 19 is connected to the output shaft 24,
Transmission output shaft speed sensor 2 for detecting the speed of shaft 24
5. A so-called vehicle speed sensor 25 is attached. The automatic transmission 30 is constituted by these components.

The actuators for driving the engine 1 and the automatic transmission 30 described above are controlled by the controller 31. The controller 31 includes a throttle opening θ, a transmission input shaft rotation speed Nt, an engine rotation speed Ne, a transmission output shaft rotation speed No, and a transmission oil temperature Toil.
, Accelerator pedal depression amount α, acceleration sensor signal G
Are input and used for control. Control controller 31
The engine torque calculation means 32 outputs control signals to the electronic control throttle 5, the fuel injection device 6, and the ignition device 2.

Next, the contents of the control block diagrams shown in FIGS. 1 and 2 will be described with reference to FIGS.
FIG. 3 shows a 2-3 shift characteristic when the present invention is used. FIG. 4 is a schematic diagram of the engagement side hydraulic pressure command value. FIG. 5 is a schematic diagram of the clutch friction coefficient. Here, a method of controlling the working oil pressure of the engagement side clutch at the time of upshift will be described. In the controller 31, first, the input shaft rotation speed Nt and the output shaft rotation speed No are determined by a rotation ratio calculating means 33.
And the rotation ratio gr of the transmission 19, that is, the so-called gear ratio is calculated. Further, the input shaft speed Nt, the engine speed Ne, and the torque converter characteristics stored in the torque converter characteristics storage means 34 (FIG. 2) of the controller 31 and the engine stored in the correction constant storage means 35 (FIG. 2). The side moment of inertia is calculated by the input shaft torque calculating means 36.
And the input shaft torque Tt of the transmission 19 is calculated. Generally, this input shaft torque is obtained by the equation (1).

Tt = t (Nt / Ne) ^* {c (Nt / Ne) ^* Ne ^* Ne−k1 ^* dNt / dt} (1) t: torque converter torque ratio (a function of Nt / Ne) c: torque Converter pump displacement coefficient (function of Nt / Ne) k1: Correction constant The input shaft rotation speed Nt, the output shaft rotation speed No (gr is applied if the friction coefficient is determined by the rotation ratio gr), and Command signal S from shift command signal generating means 37
s is input to the friction information storage means 38, and the friction information μ is calculated. For example, a friction coefficient characteristic as shown in FIG. 5 is shown.
Here, when the clutch input / output shaft rotation difference is zero, the clutch is completely engaged, and when the clutch is completely released, the rotation difference becomes infinite. At the time of upshifting, the rotation difference of the engagement side clutch starts from the infinity side, and the rotation difference becomes smaller as the hydraulic pressure rises. The solid line is the friction coefficient at the time of manufacture, and the broken line is the friction coefficient after aging. It has been found that this change in the coefficient of friction is the main factor of the torque fluctuation during gear shifting. In FIG. 3, when the clutch shown by the solid line in FIG. 5 is used while the engagement side oil pressure is constant, the transmission output shaft torque in the inertia phase fluctuates. this is,
This is consistent with the aforementioned change in the coefficient of friction. That is, if the engagement hydraulic pressure can be controlled in accordance with the change in the friction coefficient of the clutch, the torque fluctuation of the transmission output shaft in the inertia phase can be smoothed as shown by the solid line. Therefore, the friction coefficient μ, the input shaft torque Tt, and the input shaft rotation speed Nt shown in FIG. 5 are input to the pressure regulation command calculating means 39, and the engagement side hydraulic command value Pt is controlled so as to suppress the torque fluctuation. Is calculated. This Pt is a function formula of the engagement side hydraulic command value shown in FIG.
(2) and (3) are obtained.

It ^* dNt / dt + Cd ^* Nt = Tt−Tc (2) Tc = μ ^* R ^* N ^* (A ^* Pt−F) (3) It: Engine, torque converter inertia moment Cd: Viscous drag coefficient Tc: Clutch torque μ: Clutch friction coefficient R: Clutch effective radius N: Number of clutches A: Clutch piston pressure receiving area F: Clutch reaction force By using the above two equations, including the initial gear shift (the initial torque phase to the initial inertia phase) The hydraulic pressure command value Pt of the inertia phase can be represented by a function f of the horizontal axes Tt and Nt.
That is, the transmission characteristics of the above two formulas (It, Cd, etc.)
Is obtained in advance and stored, Pt is obtained without using a table. As can be seen from FIG. 4, when the above two equations are arranged, Pt changes according to the change in the friction coefficient μ (shaded portion). By controlling the clutch hydraulic pressure in feedforward using this Pt, even when a large change occurs in the clutch friction coefficient μ shown in FIG. 5, it is possible to suppress torque fluctuation during gear shifting. An example in which the above contents are executed will be described with reference to FIG. In FIG. 3, the ideal engagement side hydraulic pressure is realized by changing according to the torque fluctuation of the transmission output shaft in the inertia phase. In this case, there is a dead time and a first-order delay between the hydraulic pressure command and the actual hydraulic pressure.
0 is required (FIGS. 1 and 2). The delay compensating means 40
The rotation ratio gr is input to the, and an ideal oil pressure command value is obtained using the gr to realize the ideal oil pressure. Further, in the case of a clutch having a friction coefficient as shown by the solid line in FIG. 5, good shifting performance can be realized by two-stage hydraulic control as a simple method. In this case, when the speed ratio reaches a predetermined speed ratio a by using the speed ratio initial recognition means 41 (FIGS. 1 and 2) using the speed ratio and further considering the oil pressure delay, FIG. This is a method of switching between μ large and μ small. That is, at the beginning of the inertia phase, the clutch μ is large, so that the Pt is set low, and thereafter, the Pt is set high at the timing when the clutch μ becomes small. Here, the rotation ratio is used for the Pt switching. The reason for this is that the number of “a” for the switching is small, and the memory capacity can be reduced. If the memory capacity is not considered, the transmission input shaft rotation speed can be used. However, it is necessary to have a switching rotation speed for each rotation speed at the time of shifting, and a huge memory is indispensable. Further, in an operation in which the input shaft torque is large, the shift time becomes longer, which may cause a clutch breakage. Therefore, the engine torque is reduced by the ignition timing retard control, and the shift time is controlled within a target value. The ignition timing control is generally used, and the description of steps 44 to 49 is omitted. However, if the ignition timing retard control is executed in a so-called lean burn engine having a large air-fuel ratio, a misfire occurs, and the target torque reduction control is difficult.
The fuel amount control (air-fuel ratio control) or the air amount control is used.

Next, a method for learning the friction coefficient of the clutch when the clutch is aged will be described. In FIG. 1 and FIG. 2, the friction information storage means 38 stores the friction coefficient obtained at the time of manufacturing the clutch, and cannot consider the friction coefficient variation for each clutch. Therefore, it is necessary to detect the friction coefficient of the clutch for each clutch and for each use condition (aging) and rewrite the friction coefficient stored in the storage means 38. Therefore, the friction information detecting means 4
2 and friction information rewriting means 43 are provided. FIG. 6 shows a friction information detection method using a neural network as an example. As described above, a change in the transmission output shaft torque (input shaft torque ^* high gear side gear ratio: the same waveform as the input shaft torque) during shifting is caused by a change in the friction coefficient. Using the ratio and the hydraulic command value, friction information (coefficient) of the clutch is obtained. In FIG. 6, time series data of the input shaft torque, the rotation ratio, and the oil pressure command value is input to the input layer of the neural network at an arbitrary sampling cycle, and transmitted to the output layer via the intermediate layer. Each unit of the intermediate layer and the output layer receives the sum of the input signal Xi multiplied by the weight Wi as an input, and obtains a sigmoid function (v = 1 / (1 + exp (−ΣWiX
In i)), the input is converted and output. Thereby, the friction information of the clutch is obtained from the output layer. This friction information is input to the rewriting means 43, and the value stored in the friction information storage means 38 is rewritten. Here, the reason why the oil pressure command value is input to the friction information detecting means 42 is to judge whether the input shaft torque is changed due to a change in oil pressure or whether the input shaft torque is caused by a change in friction coefficient. As a result, it is possible to maintain good shifting performance when the clutch is aged and when there is variation during production.

[0018]

According to the present invention, since the working oil pressure of the clutch is controlled in a feed-forward manner on the basis of the clutch input / output shaft rotation difference and the friction information for each clutch, a good shift characteristic can be obtained even when the clutch friction coefficient is largely changed. Can be

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention.

FIG. 2 is a detailed block diagram of the present invention.

FIG. 3 shows 2-3 shift characteristics when the present invention is used.

FIG. 4 is a schematic diagram of an engagement side hydraulic pressure command value.

FIG. 5 is a schematic diagram of a clutch friction coefficient.

FIG. 6 is a friction information detection method using a neural network.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 19 ... Transmission, 22 ... Clutch, 28 ...
Linear solenoid, 30 ... automatic transmission, 32 ... engine torque calculation means, 33 ... rotation ratio calculation means, 36 ... input shaft torque calculation means, 38 ... friction information storage means, 39 ... pressure regulation command calculation means, 40 ... delay compensation Means, 41: Shift initial recognition means, 42: Friction information detecting means, 43: Friction information rewriting means.

Claims (10)

[Claims] A shift is executed by engaging or disengaging at least one friction engagement device in an automatic transmission connected to an engine, and adjusting a hydraulic pressure acting on the friction engagement device during the shift. A pressure command signal generating means for generating a shift start signal for the automatic transmission; and a shift command signal generating means for generating a shift start signal for the automatic transmission. Frictional information storage means for preliminarily storing information relating to a friction coefficient of the friction engagement device concerned, and a pressure adjustment calculated by the pressure adjustment command calculation means after a signal is generated from the signal generation means. A control device for an automatic transmission, wherein a command value is determined based on information in the friction information storage means. 2. A control device for an automatic transmission according to claim 1, further comprising delay compensation means for compensating for a delay in a hydraulic system of said transmission. 3. The control of an automatic transmission according to claim 1, wherein the friction information stored in the friction information storage means is changed at least in accordance with a change in the rotation speed of the transmission input shaft. apparatus. 4. A friction device according to claim 1, further comprising friction information detecting means for detecting said friction information of said friction engagement device, and rewriting friction information stored in said friction information storage means based on said detection result. A control device for an automatic transmission, comprising information rewriting means. 5. A shift is performed by engaging or disengaging at least one friction engagement device in an automatic transmission connected to an engine, and adjusting a hydraulic pressure acting on the friction engagement device during the shift. A shift command signal generating means for generating a shift start signal for the automatic transmission, comprising: a shift command signal generating means for generating a shift start signal for the automatic transmission; and a transmission output. Transmission output shaft rotation number detection means for detecting the rotation number of the shaft; transmission input shaft rotation number detection means for detecting the rotation number of the transmission input shaft; and the rotation number obtained by the two rotation number detection means. A rotation ratio calculating means for calculating an output shaft rotation ratio of the transmission by using; a shift initial recognition means capable of recognizing a shift initial state where the rotation ratio starts to change after a signal is generated from the signal generating means; A pressure regulation command calculated by the pressure regulation command calculation means when the target rotation ratio obtained by the speed change initial recognition means coincides with the rotation ratio obtained by the rotation ratio calculation means at the time of upshifting. A control device for an automatic transmission characterized by increasing the value. 6. A shift is performed by engaging or disengaging at least one friction engagement device in an automatic transmission connected to an engine, and adjusting a hydraulic pressure acting on the friction engagement device during the shift. A shift command signal generating means for generating a shift start signal for the automatic transmission, comprising: a shift command signal generating means for generating a shift start signal for the automatic transmission; and a transmission output. Transmission output shaft rotation number detection means for detecting the rotation number of the shaft; transmission input shaft rotation number detection means for detecting the rotation number of the transmission input shaft; and the rotation number obtained by the two rotation number detection means. A rotation ratio calculating means for calculating an output shaft rotation ratio of the transmission by using; a shift initial recognition means capable of recognizing a shift initial state where the rotation ratio starts to change after a signal is generated from the signal generating means; A pressure control command calculated by the pressure control command calculating means when the target rotation ratio obtained by the shift initial recognition means matches the rotation ratio obtained by the rotation ratio calculation means during downshifting. A control device for an automatic transmission, characterized in that the value is reduced. 7. A friction information storage device according to claim 5, further comprising: a friction information storage device for storing in advance information relating to a friction coefficient of said friction engagement device relating to a shift, wherein said friction information storage device calculates the friction coefficient. The control device for an automatic transmission, wherein the pressure adjustment command value is determined based on the friction information stored in the friction information storage means. 8. A control device for an automatic transmission according to claim 5, wherein the friction information stored in said friction information storage means is at least two. 9. A friction device according to claim 7, further comprising friction information detecting means for detecting said friction information of said friction engagement device, and rewriting friction information stored in said friction information storage means based on said detection result. A control device for an automatic transmission, comprising information rewriting means. 10. A shift is executed by engaging or disengaging at least one friction engagement device in an automatic transmission connected to an engine, and adjusting a hydraulic pressure acting on the friction engagement device during the shift. A shift command signal generating means for generating a shift start signal for the automatic transmission, wherein the shift command signal generating means generates a shift start signal for the automatic transmission. A friction information storage unit for storing information relating to a friction coefficient of the friction engagement device in advance, and a pressure adjustment command calculated by the pressure adjustment command calculation unit after a signal from the signal generation unit is generated. The value is determined based on the information in the friction information storage means.