JPH08210490A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE: To improve the detection accuracy of failure in an automatic transmission. CONSTITUTION: In a control device for an automatic transmission A where engaging/disengaging conditions of the first/second friction engaging devices 1, 2 are both switched at prescribed speed change time, the control device comprises an engaging start time detecting means 4 of detecting an engaging start time from speed change command time of performing a prescribed speed change till starting a rotational fluctuation of a rotary member 3 changed with a rotational speed by this speed change, engaging time detecting means 5 of detecting an engaging time from starting the rotational fluctuation of the rotary member 3 till ending the speed change and an abnormality judging means 6 of judging abnormality based on the detected engaging start time and engaging time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device capable of detecting an abnormality in an automatic transmission, and more particularly to a control device for an automatic transmission that executes so-called clutch-to-clutch shift.

[0002]

2. Description of the Related Art Conventionally, there is known an automatic transmission of a type that electrically controls engagement hydraulic pressure of a shift valve or a friction engagement device. In this type of so-called electronically controlled automatic transmission, the shift is determined based on control data such as vehicle speed and throttle opening, and the solenoid valve is driven based on the determination result, and the line pressure is adjusted. , The shift valve is switched by the signal pressure output from the solenoid valve, and the line pressure is sent from the shift valve to a friction engagement device such as a clutch or a brake via a control valve to operate the friction engagement device. Engaged. Further, the engagement pressure of the friction engagement device is continuously controlled by supplying a signal pressure to the control valve from a predetermined linear solenoid valve.

Therefore, in this type of automatic transmission, the first
In the case of clutch-to-clutch shifting executed by releasing the friction engagement device and engaging the second friction engagement device, the hydraulic pressure of the friction engagement device to be released or the hydraulic pressure of the friction engagement device to be engaged It is possible to monitor and control the rotational change of a predetermined rotating member, and as a result, clutch-to-clutch shifting can be executed without aggravating shift shock. However, the gear shift executed as described above includes various sensors for obtaining control data, calculation means for judging the gear shift based on the control data, a solenoid valve driven by its output signal, and a signal pressure from the solenoid valve. Since various devices such as control valves controlled by
If any of these devices is abnormal, the shift shock will be exacerbated.

In order to eliminate such inconvenience, the invention disclosed in Japanese Patent Laid-Open No. 347052/1992 detects an abnormality based on the engagement time of the friction engagement device. That is, in the invention described in this publication, the time from the start of the change in the number of revolutions input to the gear train to the end of the gear shift is detected as the engagement time of the friction engagement device, and the abnormality is judged by the length of the engagement time. In addition, the reference time for the determination is set according to each shift speed.

[0005]

When the shift is judged as described above, first, the shift valve is switched by the signal pressure from the solenoid valve, and the oil passage through the shift valve is changed. The hydraulic pressure is supplied to and discharged from the friction engagement device involved in gear shifting, and the torque capacity of the engaged friction engagement device gradually increases after the pack clearance of the friction engagement device is clogged. After that, the input rotation speed starts to change.

In the conventional device described in the above publication,
In the shifting process that progresses in this way, the state after the friction engagement device starts to have torque capacity is detected to determine an abnormality, but this is a limited state of the actual shifting process. Therefore, it is not always possible to perform accurate abnormality determination. In other words, even if one of the control devices has an abnormality, the engagement time falls within the allowable range due to accidental hydraulic pressure balance or the engagement start is delayed too much. If is within the allowable range, it may not be possible to detect an abnormality.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device capable of reliably and accurately detecting an abnormality in an automatic transmission.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides not only the engagement time from the start of the engagement of the friction engagement device to the end of the shift but also the output of the shift instruction. The abnormality start is determined by also detecting the engagement start time until the rotation change starts. More specifically, according to the present invention, as shown in FIG. 1, engagement between the first friction engagement device 1 and the second friction engagement device 2 during a predetermined gear shift is performed.
A control device for an automatic transmission A, which switches both disengagement states, detects an engagement start time from the time of a gear shift instruction for performing the predetermined gear shift to the start of rotational fluctuation of the rotating member 3 whose rotational speed changes due to the gear shift. Engaging start time detecting means 4
And an engagement time detecting means 5 for detecting an engagement time from the start of the rotation fluctuation of the rotating member 3 to the end of the shift, and the abnormality is judged based on the detected engagement start time and engagement time. An abnormality determining means 6 is provided.

[0009]

In the automatic transmission A to which the present invention is applied, for example, the first frictional engagement device 1 is engaged and the second frictional engagement device 2 is disengaged to execute a predetermined gear shift. When the shift is determined and the shift instruction signal is output, the time from that time until the rotation speed of the rotating member 3 changes due to the shift, that is, the engagement start time is detected. Further, the time from the rotation fluctuation of the rotary member 3 to the end of the shift, that is, the engagement time is detected.
The shift can be ended at the time when the rotation speed of the rotating member 3 is synchronized with the rotation speed in the shift stage after the shift. Then, based on the detected engagement start time and engagement time, the abnormality determination means 6 determines the abnormality. For example, if the engagement start time is long and the engagement time is short, it is determined as abnormal.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 2 is an overall control system diagram showing an embodiment of the present invention. An engine E to which an automatic transmission A is connected has an intake pipe 12 in which a main throttle valve 13 is provided.
And a sub-throttle valve 14 located upstream thereof. The main throttle valve 13 is connected to an accelerator pedal 15 and is opened / closed according to the amount of depression of the accelerator pedal 15. The sub-throttle valve 14 is opened and closed by a motor 16. An engine electronic control unit (E-ECU) 17 for controlling the motor 16 for adjusting the opening of the sub-throttle valve 14 and for controlling the fuel injection amount and ignition timing of the engine E is provided. There is. The electronic control unit 17 is mainly composed of a central processing unit (CPU), a storage unit (RAM, ROM), and an input / output interface. The electronic control unit 17 stores data for control as Engine (E /
G) Various signals such as rotational speed N, intake air amount Q, intake air temperature, throttle opening, vehicle speed, engine water temperature, and signals from brake switches are input.

In the automatic transmission A, the hydraulic control device 18 controls the shift and the lockup clutch, the line pressure, or the engagement pressure of a predetermined friction engagement device. The hydraulic control device 18 is configured to be electrically controlled, and also has first to third shift solenoid valves S1 to S3 for executing a shift and a first to third engine for controlling an engine braking state. 4 solenoid valve S4, linear solenoid valve SLT for controlling the line pressure, linear solenoid valve SLN for controlling the back pressure of the accumulator, linear for controlling the engagement pressure of a lock-up clutch or a predetermined friction engagement device A solenoid valve SLU is provided.

An electronic control unit (T-ECU) 19 for an automatic transmission that outputs a signal to these solenoid valves to control gear shift, line pressure, accumulator back pressure, etc.
Is provided. This automatic transmission electronic control unit 19
Is a central processing unit (CPU) and a storage device (RA
M, ROM) and an input / output interface, and the electronic control unit 19 has a throttle opening, vehicle speed, engine water temperature, a signal from a brake switch, a shift position, as data for control.
A signal from the pattern select switch, a signal from the overdrive switch, a signal from a C0 sensor for detecting the rotational speed of the clutch C0, which will be described later, an oil temperature of the automatic transmission,
Signals from the manual shift switch are input.

The electronic control unit 19 for the automatic transmission and the electronic control unit 17 for the engine are connected to each other so that data communication is possible, and the electronic control unit 17 for the engine transfers to the electronic control unit 19 for the automatic transmission. On the other hand, a signal such as the intake air amount per rotation (Q / N) is transmitted, and an instruction signal for each solenoid valve is sent from the automatic transmission electronic control unit 19 to the engine electronic control unit 17. A signal equivalent to, a signal instructing a shift speed, and the like are transmitted.

That is, the electronic control unit 19 for the automatic transmission
Is based on the input data and the map stored in advance, and the ON / OFF of the gear position and the lockup clutch is performed.
F, or the line pressure or the adjustment level of the engagement pressure is judged, and based on the judgment result, an instruction signal is output to a predetermined solenoid valve, and further judgment of fail or control based on it is performed. . In addition to controlling the fuel injection amount, the ignition timing, the opening degree of the sub-throttle valve 14, etc. based on the input data, the electronic control unit 17 for the engine also sets the fuel injection amount during the shift in the automatic transmission A. The output torque is temporarily reduced by reducing the amount, changing the ignition timing, or narrowing the opening of the sub-throttle valve 14.

FIG. 3 is a diagram showing an example of a gear train of the above-described automatic transmission A, and in the configuration shown here, it is configured to set five forward gears and one reverse gear. That is, the automatic transmission A shown here is used in the torque converter 20.
And a sub-transmission unit 21 and a main transmission unit 22. The torque converter 20 includes a lockup clutch 23.
The lock-up clutch 23 has a front cover 25 that is integrated with the pump impeller 24.
A member (hub) in which the turbine runner 26 and the turbine runner 26 are integrally attached
It is provided between 7 and. An engine crankshaft (not shown) is connected to a front cover 25, and a turbine runner 26 is connected to an input shaft 28.
Is connected to a carrier 30 of an overdrive planetary gear mechanism 29 that constitutes the auxiliary transmission unit 21.

The carrier 3 in this planetary gear mechanism 29
A multi-plate clutch C0 and a one-way clutch F0 are provided between 0 and the sun gear 31. The one-way clutch F0 is engaged when the sun gear 31 rotates forward relative to the carrier 30 (rotates in the rotation direction of the input shaft 28). Further, a multi-plate brake B0 for selectively stopping the rotation of the sun gear 31 is provided.
The ring gear 3 which is an output element of the subtransmission unit 21
2 is connected to an intermediate shaft 33 which is an input element of the main transmission unit 22.

Therefore, in the sub transmission unit 21, the entire planetary gear mechanism 29 rotates integrally when the multi-plate clutch C0 or the one-way clutch F0 is engaged, so that the intermediate shaft 33 has the same speed as the input shaft 28. It will rotate at low speed. Further, in the state where the brake B0 is engaged and the rotation of the sun gear 31 is stopped, the ring gear 32 is accelerated with respect to the input shaft 28 to rotate in the normal direction, and the high speed stage is established.

On the other hand, the main transmission section 22 is provided with three sets of planetary gear mechanisms 40, 50, 60, and their rotating elements are connected as follows. That is, the sun gear 41 of the first planetary gear mechanism 40 and the sun gear 51 of the second planetary gear mechanism 50 are integrally connected to each other, and the ring gear 43 of the first planetary gear mechanism 40 and the carrier 52 of the second planetary gear mechanism 50 are connected. The third planetary gear mechanism 60 and a carrier 62 are coupled to each other, and the carrier 62 is coupled to an output shaft 65. Further, the ring gear 53 of the second planetary gear mechanism 50 is connected to the sun gear 61 of the third planetary gear mechanism 60.

In the gear train of the main transmission unit 22, it is possible to set a reverse gear and four gears on the forward side, and clutches and brakes therefor are provided as follows. First, the clutch will be described. The ring gear 53 and the third gear of the second planetary gear mechanism 50 which are connected to each other.
A first clutch C1 is provided between the sun gear 61 of the planetary gear mechanism 60 and the intermediate shaft 33, and the sun gear 41 of the first planetary gear mechanism 40 and the sun gear 51 and the intermediate shaft of the second planetary gear mechanism 50 are connected to each other. A second clutch C2 is provided between the first clutch 33 and the second clutch C3.

Next, the brake will be described. The first brake B1 is a band brake, and the sun gears 41 and 5 of the first planetary gear mechanism 40 and the second planetary gear mechanism 50 are used.
It is arranged to stop the rotation of 1. A first one-way clutch F1 and a second brake B2, which is a multi-disc brake, are arranged in series between the sun gears 41 and 51 (that is, the common sun gear shaft) and the casing 66. One way clutch F1 is sun gear 41,5
1 engages when trying to rotate in the reverse direction (rotation in the direction opposite to the rotation direction of the input shaft 28). The third brake B3, which is a multi-disc brake, is the first planetary gear mechanism 4
It is provided between the zero carrier 42 and the casing 66. Then, as a brake for stopping the rotation of the ring gear 63 of the third planetary gear mechanism 60, the fourth brake B4, which is a multi-disc brake, and the second one-way clutch F2 are provided in the casing 6.
6 and 6 are arranged in parallel. The second one-way clutch F2 is adapted to be engaged when the ring gear 63 tries to rotate in the reverse direction.

In the above-described automatic transmission A, it is possible to set five forward speeds and one reverse speed by engaging and disengaging each clutch and brake as shown in the operation table of FIG. In FIG. 4, a circle indicates an engaged state, a circle indicates an engaged state during engine braking, a triangle indicates either engaged or disengaged, and a blank indicates a disengaged state.

As shown in the operation table of FIG. 4, the second
To change the speed between the third speed and the third speed, a clutch that changes the engaged / released states of the second brake B2 and the third brake B3 together.
Toe clutch shift. In order to smoothly perform this shift, the hydraulic circuit shown in FIG. 5 is incorporated in the hydraulic control device 18 described above.

In FIG. 5, reference numeral 70 indicates a 1-2 shift valve, reference numeral 71 indicates a 2-3 shift valve, and reference numeral 72 indicates a 3-4 shift valve. The communication state of each port of the shift valves 70, 71, 72 at each shift speed is determined by the respective shift valves 70, 71, 7
As shown on the lower side of No. 2. In addition, the number shows each gear stage. A third brake B3 is connected via an oil passage 75 to a brake port 74 that communicates with the input port 73 at the first speed and the second speed among the ports of the 2-3 shift valve 71. An orifice 76 is provided in this oil passage, and the orifice 76 and the third brake B3
A damper valve 77 is connected between and. The damper valve 77 sucks a small amount of hydraulic pressure to perform a buffering action when the line pressure is suddenly supplied to the third brake B3.

Reference numeral 78 is a B-3 control valve, and the engagement pressure of the third brake B3 is directly controlled by this B-3 control valve 78. That is, the B-3 control valve 78 includes a spool 79, a plunger 80, and a spring 81 interposed therebetween, and an oil passage 75 is connected to an input port 82 opened and closed by the spool 79. Output port 8 that is selectively communicated with input port 82
3 is connected to the third brake B3. Further, the output port 83 is connected to a footback port 84 formed on the tip side of the spool 79. On the other hand, in the port 85 that opens at the location where the spring 81 is arranged, the port 86 that outputs the D range pressure at the third or higher speed of the 2-3 shift valve 71 is connected via the oil passage 87. It is in communication. A lockup clutch linear solenoid valve SLU is connected to a control port 88 formed on the end side of the plunger 80.

Therefore, the B-3 control valve 78
Is configured such that the pressure regulation level is set by the elastic force of the spring 81 and the hydraulic pressure supplied to the port 85, and the higher the signal pressure supplied to the control port 88, the greater the elastic force of the spring 81. There is.

Further, reference numeral 89 in FIG. 5 denotes a 2-3 timing valve. The 2-3 timing valve 89 has a spool 9 having a small diameter land and two large diameter lands.
0, the first plunger 91, the spring 92 arranged between them, and the spool 90, and the first plunger 9
1 and a second plunger 93 arranged on the opposite side. An oil passage 95 is connected to an intermediate port 94 of the 2-3 timing valve 89, and this oil passage 95 is
Of the ports of the 2-3 shift valve 71, the port 96 is connected to the port 96 that is communicated with the brake port 74 at the shift speed of the third speed or higher.

Further, the oil passage 95 is branched on the way to open the port 97 between the small diameter land and the large diameter land.
Is connected via an orifice. The port 98, which is selectively communicated with the port 94 at the intermediate portion, is the oil passage 9
It is connected to the solenoid relay valve 100 via 9. The lock-up clutch linear solenoid valve SLU is connected to the port opened at the end of the first plunger 91, and the second brake B2 is passed through the orifice at the port opened at the end of the second plunger 93. Connected.

The oil passage 87 is for supplying and discharging hydraulic pressure to and from the second brake B2, and a small diameter orifice 101 and an orifice 102 with a check ball are interposed in the middle thereof. Further, the oil passage 103 branched from the oil passage 87 has a large diameter orifice 10 provided with a check ball that opens when the pressure is exhausted from the second brake B2.
4 is interposed, and this oil passage 103 is connected to an orifice control valve 105 described below.

The orifice control valve 105 is a valve for controlling the exhaust pressure speed from the second brake B2, and the port 107 formed in the intermediate portion so as to be opened and closed by the spool 106 has the second brake B2.
The oil passage 103 is connected to a port 108 formed below the port 107 in the figure. A port 109 formed above the port 107 to which the second brake B2 is connected in the figure is a port that is selectively communicated with the drain port, and the port 109 is connected to the port 109 via an oil passage 110. The port 111 of the B-3 control valve 78 is connected. The port 111 is a port that is selectively communicated with the output port 83 to which the third brake B3 is connected.

Of the ports of the orifice control valve 105, a control port 112 formed at the end opposite to the spring for pressing the spool 106 is connected to the port 114 of the 3-4 shift valve 72 via the oil passage 113. ing. This port 114 outputs the signal pressure of the third solenoid valve S3 at the shift speed of the third speed or lower, and the fourth speed.
It is a port for outputting the signal pressure of the fourth solenoid valve S4 at a shift speed higher than the high speed. Further, an oil passage 115 branched from the oil passage 95 is connected to the orifice control valve 105, and the oil passage 115 is selectively communicated with the drain port.

Incidentally, the port 11 for outputting the D range pressure at the second or lower speed in the 2-3 shift valve 71.
6 through the oil passage 11 at the port 117 opening at the position where the spring 92 is arranged in the 2-3 timing valve 89.
8 are connected. Also 3-4 shift valve 72
Of these, a port 119, which is communicated with the oil passage 87 at a speed lower than the third speed, is connected to the solenoid relay valve 100 via an oil passage 120.

In FIG. 5, reference numeral 121 indicates an accumulator for the second brake B2, and reference numeral 122 indicates C.
A -0 exhaust valve is shown, and reference numeral 123 is an accumulator for the clutch C0. C-0
The exhaust valve 122 is provided with the clutch C in order to apply the engine brake only in the second speed in the second speed range.
It operates so as to engage 0.

Therefore, according to the hydraulic circuit described above,
If the port 111 of the B-3 control valve 78 communicates with the drain, the engagement pressure of the third brake B3 can be directly regulated by the B-3 control valve 78, and the regulation level can be adjusted by the linear solenoid valve. SLU
Can be changed by If the spool 106 of the orifice control valve 105 is in the position shown in the left half of the figure, the second brake B2 can be communicated with the oil passage 103 through this orifice control valve 105, so that the large diameter orifice 104 is used. Exhaust pressure is possible and therefore the drain speed from the second brake B2 can be controlled.

In the above-mentioned automatic transmission, the second brake B2 is released and the third brake B3 is engaged at the second speed, and the second brake B2 is engaged and the third brake B3 is engaged at the third speed. Since the gears are engaged, the shift between the second speed and the third speed is a clutch-to-clutch shift in which the two brakes B2 and B3 are operated together. To explain the case of power-on upshift, when the upshift from the second speed to the third speed is judged and the shift instruction signal is output, the 2-3 shift valve 71 shown in FIG. The port on the left side of FIG. 5 communicates with the port on the upper right side. Therefore, since the D range pressure is output from the port 86, the hydraulic pressure is supplied to the second brake B2 via the oil passage 87, while the D range pressure is supplied to the port 85 of the B-3 control valve 78.

Further, since the brake port 74 in the 2-3 shift valve 71 communicates with the port 96, the hydraulic pressure of the third brake B3 is transmitted through the oil passage 75 to the brake port 74.
And from the port 96 to the ports 94 and 97 of the 2-3 timing valve 89. When the hydraulic pressure of the second brake B2 supplied to the second plunger 93 side of the 2-3 timing valve 89 is low, the spring 9
The pressure is adjusted according to the elastic force of 2 and the signal pressure of the linear solenoid valve SLU, and the hydraulic pressure of the third brake B3 is maintained at the pressure corresponding to the adjusted level.

On the other hand, since the hydraulic pressure of the third brake B3 is applied to the feedback port 84 of the B-3 control valve 78, the B-3 control valve 78 controls the hydraulic pressure of the third brake B3. That is, if the hydraulic pressure from the third shift solenoid valve S3 is supplied to the control port 112 of the orifice control valve 105 and the spool 106 is pushed down to the position shown in the right half of FIG. 5, the port of the B-3 control valve 78 will be described. Since 111 is communicated with the drain via the port 109 of the orifice control valve 105, the hydraulic pressure of the third brake B3 is set to a pressure corresponding to the pressure regulation level of the B-3 control valve 78. Since the signal pressure from the linear solenoid valve SLU is supplied to the control port 88 of this B-3 control valve 78, the pressure regulation level of the B-3 control valve 78 is the signal pressure of this linear solenoid valve SLU. It will be a level according to. In other words, the pressure of the third brake B3 becomes a pressure corresponding to the signal pressure of the linear solenoid valve SLU.

Therefore, after the output of the shift signal, when the hydraulic pressure of the second brake B2 gradually increases and has a torque capacity, the input rotational speed (for example, the rotational speed of the clutch C0) NC0 gradually starts to decrease. In response to this, if the signal pressure of the linear solenoid valve SLU is gradually reduced to reduce the pressure of the third brake B3, the input rotational speed NC0 is smoothly reduced, and the second brake B2 is almost completely engaged and Third brake B3 is almost completely released and the third speed is achieved. In this way, power-on from 2nd speed to 3rd speed
When the upshift is normally performed, as shown by the solid line in FIG. 6, the input rotational speed NC0 is
As the second brake B2 starts to be engaged after a predetermined time T1 has elapsed, the input rotational speed NC0 starts to decrease, the second brake B2 is almost completely engaged, and the third brake B3 is almost completely released. The rotational speed of the third speed is reached after a predetermined time T2 has elapsed.

On the other hand, for example, when the signal pressure of the linear solenoid valve SLU does not change due to some failure or the B-3 control valve 78 causes a valve stick and the pressure cannot be adjusted, The shift from the second speed to the third speed does not proceed even if the shift instruction signal is output. Then, when the pressure of the second brake B2 becomes high to some extent, the pressure of the third brake B3 is rapidly exhausted, and a power-on upshift from the second speed to the third speed occurs within an extremely short time. .

That is, the second of the 2-3 timing valve 89
Since the hydraulic pressure of the second brake B2 is applied as a signal pressure to the plunger 93 side, when the pressure becomes high to some extent, the plunger 93 pushes the spool 90 downward in FIG. 5, and as a result, the port 94
Is held in communication with the drain port. That is, the pressure is rapidly exhausted from the third brake B3.

The change in the input rotational speed NC0 in such a case is shown by the broken line in FIG. 6, and the time T1 from the output of the gear shift instruction signal to the substantial start of engagement becomes extremely long. The time T2 from the start of shifting to the end of shifting is extremely short. In such a case, the output torque fluctuates abruptly, so that the shift shock becomes worse.

When the above-mentioned abnormality (failure) occurs, some kind of failure countermeasure will be taken. However, in the control device of the present invention, the failure determination is first performed as follows. FIG. 7 shows the control routine. First, in step 1, the input signal is read, and then it is determined whether or not an upshift from the second speed to the third speed is instructed (step 2). When the upshift is not instructed, the control routine is exited, and when the upshift from the second speed to the third speed is instructed, the time for fail determination is measured ( Step 3).

The time for this fail determination is the engagement start time T1 from the gear shift instruction to the engagement start, and the engagement time T2 from the engagement start to the gear shift end. The engagement start can be detected by various conventionally known methods. For example, the input rotation speed NC0 has changed to a rotation speed (No * i2-n) obtained by subtracting a predetermined rotation speed n from a value obtained by multiplying the output rotation speed No of the automatic transmission by the gear ratio i2 of the second speed. Can be carried out by detecting Further, the detection of the end of the shift can be performed by various conventionally known methods. For example, the output speed No of an automatic transmission
The value obtained by multiplying the gear ratio i3 of the third speed by the predetermined speed n
Input rotation speed N up to the rotation speed (No x i3 + n)
This can be done by detecting that C0 has dropped.

When the above-mentioned failure occurs, the engagement start time T1 becomes long and the engagement time T2 becomes short. Therefore, it is judged whether or not the fail judgment condition is satisfied based on these times T1 and T2. To do. Specifically, it is determined whether the engagement start time T1 is equal to or longer than a predetermined reference time α and the engagement time T1 is equal to or shorter than a predetermined reference time β (step 4). If the fail determination condition is not satisfied, the routine returns without performing any control. On the contrary, if the fail determination condition is satisfied, the fail determination number NF is incremented by "1". (Step 5).

That is, the situation in which the engagement start time T1 is longer than the reference time α and the engagement time T2 is shorter than the reference time β is, for example, when the signal pressure of the linear solenoid valve SLU is high. It may be caused by a temporary factor other than the above. Therefore, even if the judgment result of step 4 is "Yes", the failure does not occur immediately, but the number of revolutions NF satisfying the failure judgment condition is counted. And

Further, in step 6, control is performed to reduce the signal pressure (SLU pressure) of the linear solenoid valve SLU at the time of the next upshift from the second speed to the third speed by a predetermined pressure. That is, the control value of the next SLU pressure is lowered.

Then, in step 7, it is judged whether or not the fail judgment rotation speed NF is a predetermined number of times γ or more. That is, when the failure determination condition is satisfied a plurality of times in which the engagement start time T1 is longer than the reference time α and the engagement time T2 is shorter than the reference time β, the hydraulic circuit and other In this case, the control at the time of failure is executed (step 8) because it is determined that the failure has occurred in the control device.

As the control at the time of the failure, various controls can be adopted. Specifically, in the above case,
Since it is a situation where the engagement pressure of the third brake B3 cannot be controlled, the control for prohibiting the second forward speed set by engaging the third brake B3 may be performed. This is executed, for example, by switching to a shift diagram in which the second speed range is not set and performing shift control. If the result of the determination in step 7 is "no", the process returns.

Therefore, according to the control shown in FIG. 7, not only the time from the change of the input speed NC0 to the end of the gear shift but also the time until the change of the input speed NC0 is detected, these values are detected. Engagement start time T1 and engagement time T of
Since the failure is judged based on both of the two, not only mechanical failure such as friction plate wear but also various failures such as valve stick and hydraulic control solenoid valve failure can be reliably detected. it can. In particular, as described with reference to FIG. 7, the number of times the fail determination condition is satisfied is counted, and when the fail determination condition is satisfied, control such as temporarily changing the control value is performed. It is possible to surely discriminate an abnormality caused by a statistical or accidental factor from an abnormality caused by a failure, and in this respect also, the failure can be detected more reliably.

In the control example shown in FIG. 7, the engagement start time T1 and the engagement time T2 are calculated based on the change in the input rotational speed NC0 during the upshift from the second speed to the third speed. Therefore, the control shown in FIG. 7 is executed at the power-on upshift by depressing the accelerator pedal. That is, the accelerator pedal is released and the second
In the case of power off / upshift in which an upshift from the third speed to the third speed occurs, the input speed NC0 sharply decreases regardless of the engaged / released states of the second brake B2 and the third brake B3. Therefore, in such a case, fail determination cannot be performed based on the engagement start time T1 and the engagement time T2 obtained from the input rotational speed NC0. Further, the timing of engagement / disengagement of the friction engagement devices such as the second brake B2 and the third brake B3 is restricted depending on the speed of supply / discharge of hydraulic pressure to / from these friction engagement devices. If the value is low, the viscosity is high, and the control is delayed due to the viscosity.Therefore, the control described above is based on the engine water temperature or the oil temperature of the automatic transmission. It is preferable to execute when the above is the case.

In the above-described embodiment, the signal pressure of the linear solenoid valve SLU is reduced when the fail determination condition is satisfied, but the change of the control value of the linear solenoid valve SLU is essential to the present invention. It is also possible to implement it as needed, instead of the requirement. Further, such a change of the control value is not carried out only in the case of the fail judgment / detection, but can be appropriately executed when the detected value is abnormal in the control process of the automatic transmission.

Further, in the above embodiment, the fail time control is executed only after the fail judgment number reaches the reference number, but the present invention is not limited to the above embodiment, and the fail judgment condition is If the condition is satisfied, the fail time control may be immediately executed. In short, the present invention only needs to determine the failure based on both the engagement start time and the engagement time.

The present invention can be implemented for an automatic transmission having a gear train or a hydraulic circuit different from the gear train or the hydraulic circuit shown in FIGS. 3 and 5 or a control device therefor. This invention also
It is needless to say that the present invention can be applied not only to the upshift from the second speed to the third speed but also to the fail determination at the time of another gear shift. Further, in the present invention, the rotating member for detecting the rotation speed is not limited to the member having the same rotation speed as the input rotation speed.

[0053]

As described above, according to the present invention,
After the gear change instruction signal is output, there are two detection times: the time until the engagement of the friction engagement device that executes the gear shift is started, and the time from the start of engagement of the friction engagement device to the end of the gear shift. Since the failure is determined based on the failure, it is possible to reliably detect the failure due to any abnormality in the mechanical system, the hydraulic system, or the electrical system.

[Brief description of drawings]

FIG. 1 is a block diagram showing the present invention by functional means.

FIG. 2 is a block diagram schematically showing a control system of an embodiment of the present invention.

FIG. 3 is a diagram mainly showing a gear train of the automatic transmission.

FIG. 4 is a diagram showing an operation table for setting each shift speed.

FIG. 5 is a diagram showing a part of a hydraulic circuit.

FIG. 6 is a diagram for explaining an engagement start time and an engagement time based on a change in the input rotation speed at the time of power-on upshift from the second speed to the third speed.

FIG. 7 is a flowchart showing an example of a fail detection control routine.

[Description of Reference Signs] 1 first friction engagement device 2 second friction engagement device 3 rotating member 4 engagement start time detection means 5 engagement time detection means 6 abnormality determination means A automatic transmission

Claims (1)

[Claims] 1. A control device for an automatic transmission that switches the engagement and disengagement states of a first friction engagement device and a second friction engagement device at the time of a predetermined gear shift, and a shift instruction for performing the predetermined gear shift. An engagement start time detecting means for detecting an engagement start time from the time until the rotational fluctuation of the rotary member whose rotational speed changes due to the speed change starts, and an engagement time from the start of the rotational fluctuation of the rotary member to the end of the speed change. A control device for an automatic transmission, comprising: an engagement time detection means for detecting the abnormality, and an abnormality determination means for determining an abnormality based on the detected engagement start time and engagement time.