JPH1096465A - Transmission control device and transmission control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a start of an accurate torque phase even at rough road running time, and excellently maintain a transmission characteristic on a rough road by detecting a rate of change in time of rotating speed of an output shaft of an automatic transmission, and outputting it to a pressure adjusting command generating means by performing an operation on an oil pressure value on the basis of its value. SOLUTION: When a vehicle travels, turbine rotating speed Nt, engine speed Ne, transmission output shaft rotating speed No, an acceleration sensor signal G or the like are inputted to a control controller 31. An operation 32 is performed on a rate of change in rotating speed of a transmission output shaft on the basis of a signal of the rotating speed No, and a rate of change in this rotating speed is inputted to a torque phase recognizing means 33 together with a transmission command signal from a transmission command signal generating means 34, and a torque phase is recognized. When both of the transmission command signal and a change in a rate of change in rotating speed coincide with each other, it is judged as a start of a torque phase for the first time, and the transmission command signal is generated. An computation 35 is performed on a command to hold oil pressure to be supplied to frictionally engaging devices 22 and 23 in a constant value simultaneously with a change in the transmission command signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device and a control method for controlling a hydraulic pressure at the time of gear shifting in an automatic transmission of a motor vehicle, and more particularly to a frictional engagement device which directly controls an clutch hydraulic pressure electrically. The present invention relates to a shift control device and a shift control method for performing disengagement and engagement.

[0002]

2. Description of the Related Art The time change of the input rotation speed of a clutch of an automatic transmission during a speed change includes a period in which the torque changes without changing the rotation speed, and a period in which the rotation speed changes. The torque phase and the latter are called the inertia phase.

[0003] This type of conventional technology is disclosed in, for example, Japanese Patent Application Laid-Open
As described in -265756, detection of the start of the torque phase at the time of upshifting is performed by recognizing a change state of a signal from an acceleration sensor attached to the vehicle body,
A device that controls a hydraulic pressure acting on a friction engagement device based on this change is known.

[0004]

SUMMARY OF THE INVENTION
As disclosed in Japanese Patent Application Laid-Open No. 3-265756, an apparatus which detects the start of a torque phase at the time of upshifting by using an acceleration sensor signal and controls a hydraulic pressure applied to a friction engagement device,
When the vehicle travels on a rough road such as a gravel road, there is a problem that the vibration of the vehicle body due to the road surface is added to the signal of the acceleration sensor, and the start of the torque phase cannot be accurately detected.

SUMMARY OF THE INVENTION An object of the present invention is to provide a shift control device and a shift control method capable of accurately detecting the start of a torque phase even on a rough road and obtaining good shift characteristics on a rough road. is there.

[0006]

In order to achieve the above object, the present invention detects the start of the torque phase from the time change rate of the rotation speed of the output shaft of an automatic transmission without using an acceleration sensor. As a result, good shifting characteristics can be obtained even when the vehicle travels on a rough road.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment) Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram of a power train of an automobile to which the present invention is applied and a control device thereof. Engine 1
An intake pipe 4 for taking in air is provided with an electronic control throttle 5, which adjusts 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 a number of fuel injection valves 8 corresponding to the number of cylinders of the engine 1. Electronic control throttle 5
Is that the throttle valve 10 is driven by the actuator 9 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. The engine 1 is provided with an ignition device 2. The ignition device 2 has a number of ignition plugs 3 corresponding to the number of cylinders of the engine 1.

A flywheel 12 is attached to a crankshaft 11 of the engine 1. Flywheel 12
Is mounted with an engine output shaft 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 torque converter output shaft 18 is directly connected to a stepped transmission mechanism 19. Here, a so-called clutch-to-clutch speed change mechanism 19 in which a speed change is performed by engaging and disengaging the two friction engagement devices 22 and 23 will be described as an example.

[0010] A turbine (transmission input shaft) rotation speed sensor 20 for measuring the turbine rotation speed Nt is attached to the torque converter output shaft 18. The transmission mechanism 19
It is composed of a planetary gear 21, frictional engagement devices 22, 23,
By engaging and disengaging the devices 22 and 23, the gear 2
The gear ratio is changed to execute the gear shift. These devices 2
2 and 23 are controlled by spool valves 26 and 27 and linear solenoids 28 and 29 (pressure adjusting devices), respectively. The speed change mechanism 19 is connected to an output shaft 24, and a transmission output shaft speed sensor 25 for detecting the speed of the shaft 24, that is, a so-called vehicle speed sensor 25 is attached. The automatic transmission 30 is constituted by these components.

The actuator for driving the engine 1 and the automatic transmission 30 described above is controlled by the controller 31.

FIG. 2 is a hardware configuration diagram of the controller 31. It is configured to include a filter 48 and a waveform shaping circuit 49 to which signals from various sensors are input, a single-chip microcomputer 50, and a drive circuit 51 that outputs drive control signals to actuators such as various valves. The computer 50 executes a CP for executing various operations.
U (Central Processing Unit) 51 and R in which programs and data to be executed by CPU 51 are stored.
A read-only memory (OM) 52, a random access memory (RAM) 53 for temporarily storing various data, a timer 54, a serial communication interface (SCI) circuit 55, an input / output (I / O) circuit 56, and an A / D (Anal
og to Digital) converter 57.
That is, various functions of the control controller 31
1 is achieved by executing a predetermined operation using a program or data stored in the ROM 52 or the RAM 53.

The hardware configuration of the controller 31 includes a single-chip configuration, a configuration in which a plurality of single-chip microcomputers communicate with each other via a dual-port RAM, and a configuration in which a plurality of single-chip microcomputers are connected to a LAN (Local Area Network). ).

The controller 31 receives the throttle opening θ, turbine speed Nt, engine speed Ne, transmission output shaft speed No, transmission oil temperature Toil, accelerator pedal depression α, acceleration sensor signal G, and the like. And used for control.

The engine torque control means 37 in the controller 31 outputs control signals to the electronic control throttle 5, the fuel injection device 6, and the ignition device 2. These control signals are also used to suppress torque fluctuation during gear shifting.

The controller 31 executes a control system for hydraulic pressure acting on the friction engagement device when traveling on a rough road such as a gravel road. The rotational speed change rate calculating means 32 calculates the rotational speed change rate of the transmission output shaft by subtracting the signal of the rotational speed No.

At the time of upshifting, high-precision torque phase detection is required to perform engagement and disengagement of the engagement device and obtain good shift characteristics. The rotation speed change rate is:
Since a waveform equivalent to the torque sensor signal is obtained, the start of the torque phase can be recognized.

FIG. 3 is a time chart comparing the temporal change of the acceleration sensor signal and the signal of the transmission output shaft rotation rate change rate. When the vehicle is traveling on a rough road, the fluctuation of the torque phase when traveling on a paved road is shown. Therefore, it is difficult for the acceleration sensor to recognize the shift state including the torque phase.
However, in the case of the rotational speed change rate, the waveform has a level at which the torque phase can be recognized, although a slight variation occurs as compared with when traveling on a pavement road. In other words, the rate of change in the number of revolutions enables the detection of the torque phase even when traveling on a rough road such as a gravel road.

Next, the torque phase recognition means 33 shown in FIG.
The shift command signal from the shift command signal generating means 34 and the rotational speed change rate are input. The generation of the shift command signal is a trigger for starting to supply the hydraulic pressure that acts on the friction engagement device for shifting. That is, when the speed change command signal and the change in the rotational speed change rate are both compatible, it is determined that the torque phase has started for the first time. If only the change in the rotational speed change rate is used, even when the throttle valve 10 is closed, it is erroneously recognized as the start of the torque phase.

The clutch oil pressure command value calculating means 35 calculates a command value for keeping the oil pressure supplied to the friction engagement devices 22 and 23 at a certain value simultaneously with the change of the shift command signal. Thereafter, based on the recognition result of the start of the torque phase, the command value of the oil pressure supplied to the disengagement-side friction engagement device at the time of upshifting is stepped down, and a good change of the friction engagement device near the torque phase is performed. carry out.

In the inertia phase, a hydraulic pressure correction value corresponding to an operation state for suppressing torque fluctuation is obtained, and the base clutch hydraulic pressure command value is corrected. Then, the pressure regulation command generating means 36 outputs the calculated clutch oil pressure command value to the linear solenoids 28 and 29.

FIG. 4 shows a time chart when the above-described series of hydraulic control methods are executed. Here, a description will be given by taking as an example a 2-3 shift when traveling on a rough road. The rotational speed change rate when the shift command signal changes from the second speed to the third speed is stored (black circle on the left), and thereafter, it is determined whether the rotational speed change rate matches the stored rotational speed change ratio (black circle on the right). to decide. The right black circle is a torque phase recognition point.

The on-coming clutch hydraulic pressure command value is set to a value such that the value of the rate of change of the rotational speed indicated by the two black circles in FIG. 4 coincides with each other when the shift command signal changes, and this value is maintained until the inertia phase starts. Hold the torque value. Thereafter, the clutch oil pressure is corrected in accordance with the change in the gear ratio, thereby suppressing the torque fluctuation in the inertia phase.

The disengagement side clutch oil pressure command value is set to a value just before the disengagement side engagement device disengages when the shift command signal changes, and is changed stepwise according to the recognition of the torque phase. Thereby, the engagement and disengagement of the engagement device at the time of starting the gear shift are performed satisfactorily, and a good gear shift characteristic is obtained.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 5 is a control block diagram of a system for controlling a friction engagement device such as a clutch by hydraulic pressure. The means 25 to 36 are the same as those described with reference to FIG.

In the speed change control using the rate of change of the rotational speed of the first embodiment, the case where the engagement device changes over time is not considered. In the present embodiment, a shift control that takes this point into consideration will be described. First, rotation signals from the transmission input shaft rotation speed detecting means 20 and the engine output shaft rotation speed detecting means 13 are input to the transmission input shaft torque calculating means 37, and the controller 3
The transmission input shaft torque is calculated using the torque converter characteristics stored in the torque converter characteristics storage means 38 provided in the unit 1. Next, the rotation signals from the transmission output shaft rotation speed detection means 25 and the transmission input shaft rotation speed detection means 20 are input to the transmission input / output shaft rotation ratio calculation means 39, and the transmission input / output shaft rotation ratio is calculated. It recognizes the inertia phase. And
The transmission input / output shaft rotation ratio, the input shaft torque, and the torque change rate limit value for recognizing a temporal change stored in the torque change rate limit value storage means 40 are input to a torque change rate calculation means 41.

The calculating means 41 first calculates the torque transmission ratio obtained from the transmission input / output shaft rotation ratio (at the end of the torque phase in the case of a shift up, or at the start of the torque phase in the case of a downshift) at the start of the torque phase. The change rate of the transmission output shaft torque obtained by multiplying the input shaft torque by the input signal torque is compared with the change rate limit value, and the signal of the time-dependent change state of the engagement device is clutched. Output to the hydraulic pressure correction means 42.

In the correcting means 42, the hydraulic pressure is corrected so that the calculated change rate falls below the change rate limit value. Then, the correction value is input to the command value calculating means 35.

FIGS. 6 and 7 show time charts in the case where the above hydraulic pressure correction method is executed. FIG. 6 shows the case of an upshift, and shows the relationship between the estimated transmission output shaft torque and the engagement-side clutch oil pressure command value at the time of shifting.

Since the estimated torque is calculated based on the rotational speed as described above, it is difficult to detect a torque change in a torque phase that occurs without a change in the rotational speed. However, since the inertia phase has a waveform equivalent to the actual torque,
The present invention can be applied to learning control for suppressing a torque fluctuation due to a temporal change of the engagement device. For example, the estimated transmission output shaft torque before and after the torque phase is recognized (two black circles), and the hydraulic pressure command value is changed as shown by a broken line so that the two torques match, thereby changing the torque in the inertia phase shown by the broken line. Can be suppressed.

FIG. 7 shows the case of a downshift, in which the relationship between the estimated transmission output shaft torque and the release-side clutch oil pressure command value at the time of shifting is described. For example, the rate of change of the estimated transmission output shaft torque in the inertia phase is calculated, and it is determined whether the rate of change is below the rate-of-change limit value indicated by the dashed line (broken line). If it falls below, the torque fluctuation in the inertia phase indicated by the broken line can be suppressed as indicated by the solid line by changing the release side hydraulic command value as indicated by the broken line.

Next, a control method for determining a bad road in FIG. 5 will be described below. For the determination of the rough road, the rate of change in the rotational speed of the transmission output shaft obtained by the rate-of-rotation change rate calculating means 32 is used.
The rotational speed change rate and the determination value stored in the rough road determination value storage means 43 are input to the rough road determination means 44, and it is determined whether the amplitude and frequency of the rotational speed change rate exceed the determination values.

If it exceeds, the correction inhibit signal generation means 4
A signal indicating that the vehicle is traveling on a rough road is input to 5, and a correction prohibition signal is input to the correction unit 42. On rough roads,
Even during a gear shift, the vibration from the road surface is added to the torque fluctuation due to the gear shift, so that the driver cannot recognize the torque fluctuation due to the gear shift. Further, when the torque fluctuation occurs from the tire side as described above, if the hydraulic pressure is reduced during the gear shift and the torque fluctuation suppression control in the inertia phase is performed, an impact may be applied to the engagement device and the engagement device may be damaged. is there. Therefore, it is necessary to prohibit torque fluctuation suppression control during gear shifting by hydraulic pressure. Also, when suppressing the torque fluctuation due to the change over time of the engagement device using the estimated torque, it is difficult to determine whether the change is due to the rough road or the change over time when traveling on a rough road. It is necessary to perform the correction of the aging change at times other than the road.

Further, a control method corresponding to the accuracy of the torque phase recognition based on the rate of change in the number of revolutions due to the difference in the rough road will be described below. When the torque phase can be recognized based on the rotational speed change rate, the hydraulic control of the engagement device can be performed based on the torque phase recognition as described above. However, when there is a protrusion on the road surface and the vibration transmitted to the tire is large, it is difficult to recognize the torque phase based on the rotation rate change rate. Therefore, the rough road determination means 4
In step 4, when the amplitude of the rate of change in the rotational speed is abnormally large, a switching signal is generated in the control switching means 46 to change the hydraulic control method of the engagement device.

Time control is applied to the changed hydraulic control system. First, the shift start time from the change of the signal at the command signal generating means 34 to the torque phase recognition timing is stored in the shift start time storing means 47 for each type of engine addition and shift. If it is determined that the road is severely bad, it is difficult to recognize the torque phase based on the rate of change in the number of revolutions. Therefore, the control of the release-side clutch oil pressure command value is executed using the latest shift start time. Thereby, it is possible to realize a good change gear shift when traveling on a severely bad road.

Conversely, hydraulic control based on the shift start time which is not affected by the road surface is mainly performed, and learning control of the start time is performed on the normal road surface based on the torque phase recognition based on the rate of change in the number of revolutions, whereby the shift change is performed. It can also be achieved.

Next, a third embodiment of the present invention will be described with reference to the drawings.

FIG. 8 is a control block diagram similar to FIG.
Is a time chart when this control is executed.

First, a hydraulic control method using the acceleration sensor signal and the rate of change in the number of revolutions will be described. Basically, on a lightly rough road (the range up to the end of the 1-2 shift in FIG. 9), the torque phase is recognized using the rotation speed change rate, and the hydraulic pressure supplied to the engagement device is controlled. After that, severe bad road (2-3 in FIG. 9)
In the range up to the end of the shift, the shift command signal is represented by a solid line), and the frequency of the signal of the acceleration sensor 60 and the rotational speed change rate obtained by the rotational speed change rate calculating means 32 are analyzed. The severe bad road is determined and the shift timing is delayed as indicated by the broken line.

First, the vehicle speed obtained by the rotation speed detecting means 25 and the engine load obtained by the engine load detecting means 61 are inputted to a speed ratio calculating means 62 to calculate a shift command signal.
On a normal road surface, the speed change command signal is transmitted to the speed ratio output means 63.
And drives the speed change actuator 64 to change the speed. However, when the rough road determination means 44 determines that the road is severely bad, the shift inhibition signal generation means 65 generates a shift inhibition signal to the output means 63 to inhibit the shift. That is, FIG.
As in the case of the 2-3 shift command indicated by the dashed line, the shift command signal is executed after the severe bad road ends. This is performed for the purpose of reducing damage to the engagement device due to torque fluctuation transmitted from the tire as described above.

When the engine speed is increased due to the long and severe bad road, the driver may be uncomfortable by the engine speed noise. The engine speed limit value (stored in the engine speed limit value storage means 66) is compared by the signal generation means 65 to determine whether or not a shift is performed.

Here, the hydraulic command value used for shifting is a 24-engaged hydraulic command value that starts at the second and fourth speeds,
And the 34 engagement-side hydraulic command values that start at the 4th speed and the 4th speed. In the 1-2 shift, the one-way clutch is disengaged and the shift is performed with the rise of the 24 engagement side hydraulic command value.

Another use of the acceleration sensor signal is learning control. Since the acceleration sensor signal has the same waveform as the estimated torque, the same hydraulic pressure correction control as described above can be executed.

[0045]

According to the present invention, accurate start of the torque phase can be detected even when vibration transmitted from a tire on a rough road such as a gravel road or a center line marker is input to the friction engagement device. Good shifting characteristics on the rough road are obtained.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention and is a schematic diagram of a configuration of a power train and a shift control device of an automobile.

FIG. 2 is a hardware configuration diagram of a control controller.

FIG. 3 is a time chart comparing a temporal change of an acceleration sensor signal and a signal of a transmission output shaft rotation rate change rate;

FIG. 4 is a time chart when the control of FIG. 1 is executed.

FIG. 5 shows a second embodiment of the present invention and is a control block diagram of a shift control device.

FIG. 6 is a time chart when the control of FIG. 5 is executed in the case of upshifting.

FIG. 7 is a time chart when the control of FIG. 5 is executed in the case of downshifting.

FIG. 8 shows a third embodiment of the present invention and is a control block diagram of a shift control device.

FIG. 9 is a time chart when the control of FIG. 8 is executed.

[Explanation of symbols]

Reference numeral 22: friction engagement device, 25: transmission output shaft rotation speed sensor, 29: linear solenoid, 31: control controller, 32: rotation speed change rate calculation means, 35: clutch oil pressure command value calculation means, 36: pressure regulation command Means of generation.

Claims (16)

[Claims] 1. A shift control device comprising a pressure regulation command generating means for controlling the engagement / disengagement operation of a friction engagement device of an automatic transmission by hydraulic pressure to shift the automatic transmission, wherein the output of the automatic transmission is Rotation speed change rate detection means for detecting a time change rate of the rotation speed of the shaft; calculating a value of the hydraulic pressure based on a signal from the rotation speed change rate detection means; And a pressure control value calculating means for outputting to the transmission. 2. A shift control device comprising a pressure regulation command generating means for controlling the engagement / disengagement operation of a friction engagement device of an automatic transmission by hydraulic pressure to shift the automatic transmission. A shift command signal generating means for generating a shift command signal for starting operation; a transmission output shaft speed sensor for detecting a speed of an output shaft of the automatic transmission; and a transmission output shaft speed sensor. Rotation speed change rate calculating means for calculating the time change rate of the output shaft rotation speed of the transmission using the output shaft rotation speed, and the rotation speed change rate calculation means during a shift operation started by the shift command signal. Torque phase recognizing means for recognizing a torque phase from the value of the output shaft rotational speed change rate obtained in the step (a), and calculating the oil pressure value based on a signal from the torque phase recognizing means. Pressure command generation Shift control apparatus characterized by having a pressure adjustment value calculating means for outputting to the stage. 3. A shift control device comprising a pressure control command generating means for controlling the engagement / disengagement operation of a friction engagement device of an automatic transmission by hydraulic pressure to shift the automatic transmission, wherein the automatic transmission and an engine are provided. A torque converter input shaft speed sensor for detecting an input shaft speed of the torque converter, a memory holding torque converter characteristic data representing input output characteristics of the torque converter, and the torque converter input shaft. Output shaft torque calculating means for calculating an output shaft torque of the automatic transmission based on an input shaft rotation speed obtained by a rotation speed sensor and a torque converter characteristic held in the memory; Means for calculating a time change rate of the output shaft torque calculated by the means, and a torque calculated by the torque change rate calculating means. Torque change rate comparing means for comparing the change rate with a predetermined value; calculating a hydraulic pressure value based on a signal from the torque change rate comparing means; and outputting the calculation result to the pressure regulation command generating means. And a pressure control value calculating means. 4. A shift control device comprising a pressure adjusting command generating means for controlling the engagement / disengagement operation of a friction engagement device of an automatic transmission by hydraulic pressure to shift the automatic transmission, wherein the shift of the automatic transmission is changed. Shift command signal generating means for generating a shift command signal for starting operation, and an output for generating a signal for suppressing a temporal variation of the output shaft torque of the automatic transmission based on a signal from the shift command signal generating means. Shaft torque fluctuation suppressing means, a road surface state detecting means for detecting a road surface state, and a bad road for determining whether or not the road is bad by comparing a value detected by the road surface state detecting means with a predetermined value. A shift control device, comprising: a determination unit, wherein when the rough road determination unit determines that the road is bad, output of a signal output from the output shaft torque fluctuation suppression unit is prohibited. 5. The automatic transmission according to claim 4, further comprising: an acceleration sensor for detecting a longitudinal acceleration of a vehicle equipped with the automatic transmission; and detecting a temporal change rate of a rotation speed of an output shaft of the automatic transmission. The road surface state detecting means compares a value from the acceleration sensor with a value from the rotational speed change detecting means to detect a road surface state. Shift control device characterized by the following. 6. A shift control device comprising a pressure regulation command generating means for controlling the engagement and disengagement operation of a friction engagement device of an automatic transmission by hydraulic pressure to shift the automatic transmission, wherein the output of the automatic transmission is Rotation speed change rate detection means for detecting a change rate of the rotation speed of the shaft, a torque converter input shaft rotation speed sensor for detecting a rotation speed of an input shaft of a torque converter provided between the automatic transmission and an engine, A memory that holds torque converter characteristic data representing an input / output characteristic of the torque converter; an input shaft rotation speed obtained by the torque converter input shaft rotation speed sensor; and a torque converter characteristic held in the memory. Output shaft torque calculating means for calculating an output shaft torque of the automatic transmission; and a time change rate of the output shaft torque calculated by the output shaft torque calculating means. Torque change rate calculating means for calculating; torque change rate comparing means for comparing the torque change rate calculated by the torque change rate calculating means with a predetermined value; road surface state detecting means for detecting a road surface state; A bad road determining means for comparing a value detected by the road surface state detecting means with a predetermined value to determine whether or not the road is a bad road; In this case, the signal from the rotational speed change rate detecting means is switched to the signal from the torque change rate comparing means, and the value of the oil pressure is calculated based on the signal. And a pressure control value calculating means for outputting to the control means. 7. A shift control device having a pressure regulation command generating means for controlling the engagement / disengagement operation of a friction engagement device of an automatic transmission by hydraulic pressure to shift the automatic transmission, wherein a state of a road surface is detected. A road condition detection unit, and a bad road determination unit that determines whether or not the road is a bad road by comparing a value detected by the road condition detection unit with a predetermined value. A shift control device for prohibiting a shift operation of the automatic transmission when it is determined that the road is bad. 8. The engine output shaft according to claim 7, wherein: an engine output shaft speed sensor for detecting the speed of the output shaft of the engine; a memory for holding a limit value of the speed of the output shaft of the engine; An engine output shaft speed comparison means for comparing the engine output shaft speed detected by a speed sensor with the limit value stored in the memory; and a result of the comparison by the engine output shaft speed comparison device, A shift control device, wherein prohibition of a shift operation of the automatic transmission is canceled when an output shaft rotation speed exceeds the limit value. 9. A shift control method for shifting the automatic transmission by hydraulically controlling an engagement / disengagement operation of a friction engagement device of the automatic transmission, the time change rate of the rotation speed of an output shaft of the automatic transmission. Detecting the rate of change of the rotational speed, calculating the value of the hydraulic pressure based on the value of the rate of change of the rotational speed, and starting the shift operation of the automatic transmission based on the value of the hydraulic pressure. Shift control method. 10. A shift control method for shifting the automatic transmission by controlling the engagement / disengagement operation of a friction engagement device of the automatic transmission with a hydraulic pressure, comprising: detecting a rotation speed of an output shaft of the automatic transmission; A time change rate of the output shaft rotation speed of the automatic transmission is calculated using the output shaft rotation speed, and the output shaft is rotated during a shift operation signal started by a shift command signal for starting a shift operation of the automatic transmission. Recognizing the torque phase from the value of the rotational speed change rate, calculating the value of the hydraulic pressure based on the recognized value of the torque phase, and starting the shift operation of the automatic transmission based on the value of the hydraulic pressure. A shift control method comprising: 11. A shift control method for shifting the automatic transmission by hydraulically controlling an engagement / disengagement operation of a friction engagement device of the automatic transmission, wherein a torque provided between the automatic transmission and an engine is provided. Detecting the input shaft rotation speed of the converter, and calculating the output shaft torque of the automatic transmission based on the input output characteristics of the torque converter and the input shaft rotation speed of the torque converter stored in a memory; Calculating the time change rate of the shaft torque; comparing the time change rate of the output shaft torque with a predetermined value; calculating the hydraulic pressure value based on the comparison result; and calculating the hydraulic pressure value based on the hydraulic pressure value. A shift control method, wherein a shift operation of the automatic transmission is started. 12. A shift control method for shifting the automatic transmission by controlling the engagement / disengagement operation of a friction engagement device of the automatic transmission by hydraulic pressure, wherein a state of a road surface is detected, and a value of the road surface state is determined in advance. A determination is made as to whether the vehicle is on a rough road by comparing the determined value with a predetermined value. If the road is determined to be a bad road, the automatic shift is generated based on a shift command signal for starting a shift operation of the automatic transmission. A shift control method comprising: prohibiting the output of a signal that suppresses a temporal variation of the output shaft torque of the machine. 13. The longitudinal acceleration according to claim 12, wherein the longitudinal acceleration of a vehicle equipped with the automatic transmission is detected, a temporal change rate of the rotation speed of an output shaft of the automatic transmission is detected, and the longitudinal acceleration is detected. And comparing the value of the rotational speed change rate with the value of the rotational speed change rate to detect the state of the road surface. 14. A shift control method for shifting the automatic transmission by controlling the engagement / disengagement operation of a friction engagement device of the automatic transmission by oil pressure, wherein the rate of change of the rotation speed of the output shaft of the automatic transmission is determined. Detecting the number of revolutions of an input shaft of a torque converter provided between the automatic transmission and the engine; and detecting a torque converter characteristic representing an input output characteristic of the torque converter held in a memory and an input of the torque converter. Calculating an output shaft torque of the automatic transmission based on a rotation speed of the shaft; calculating a time change rate of the output shaft torque; comparing the time change rate of the output shaft torque with a predetermined value; Detecting the condition of the road surface, comparing the value of the road surface condition with a predetermined value to determine whether or not the road is bad, and when determining that the road is bad, determining the road speed from the rate of change in rotation speed. Output shaft torque Switching between the rate of change, it computes the value of the oil pressure based on said value, the shift control method characterized by starting the shift operation of the automatic transmission based on the value of the hydraulic pressure. 15. A shift control method for shifting the automatic transmission by controlling the engagement / disengagement operation of a friction engagement device of an automatic transmission by hydraulic pressure, wherein a state of a road surface is detected, and a value of the road surface state is determined in advance. A shift control method comprising: determining whether or not the vehicle is on a rough road by comparing the determined value with a predetermined value; and determining that the vehicle is on a rough road, prohibiting a shift operation of the automatic transmission. 16. The engine according to claim 15, wherein the number of revolutions of the output shaft of the engine is detected, and the number of revolutions of the engine output shaft is compared with a limit value of the number of revolutions of the output shaft of the engine stored in the memory. A shift control method according to claim 1, wherein, as a result of the comparison, when the engine output shaft rotation speed exceeds the limit value, the prohibition of the shift operation of the automatic transmission is released.