JPH0560221A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent the shock under the fail condition when an engine brake is effective. CONSTITUTION:In an automatic transmission for supplying the oil pressure to a frictional fitting device 1 for engine brake at a predetermined low speed stage through a valve 3 to be controlled by an electric means 2, when a fail of the electric means 2 and the valve 3 is detected by a fail detecting means 4, a variable speed prohibiting means 5 prohibits speed change to a low speed stage such as a first speed and a second speed or the like, or a variable speed stage command means 7 shifts up forcedly to a variable speed stage at a third speed or more.

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 shift by an automatic transmission for a vehicle.

[0002]

2. Description of the Related Art Generally, an automatic transmission for a vehicle changes a friction engagement device such as a clutch or a brake that supplies hydraulic pressure by operating a shift valve based on a running state of the vehicle, and gear shifts accordingly. It is configured to change gears by changing the power transmission path of the mechanism. Further, the timing of engagement or disengagement of the friction engagement device greatly affects the shift shock, so the hydraulic pressure supplied to or discharged from the friction engagement device is regulated. Recently, the shift valve switching operation for shifting and the hydraulic pressure adjustment during shifting have come to be performed through an electrically controllable device such as a solenoid valve. As an example, JP-A-1-24285
In the device described in Japanese Patent Publication No. 7, the hydraulic pressure supplied to the friction engagement device engaged during engine braking is regulated by the modulator valve, and the regulated level is controlled by the linear solenoid valve.

[0003]

The above-mentioned conventional device is for obtaining the engine braking state according to the vehicle speed, and by controlling the linear solenoid valve according to the vehicle speed, the hydraulic pressure proportional to the current value is obtained. It is generated and is applied to the control port of the modulator valve. The modulator valve has a structure similar to that widely used in general, in which a feedback pressure is applied to one end of a spool, and an elastic force of a spring and a hydraulic pressure of the control port are applied to an end opposite to the feedback pressure. The pressure control level is higher as the control hydraulic pressure output from the linear solenoid valve is higher. However, in such a configuration, since it is similar to that the linear solenoid valve directly controls the modulator valve, if the linear solenoid valve fails, the shift shock will be greatly affected. That is, the engine braking state at the low speed stage is selected by the driver's conscious manual operation, and in normal driving, the one-way clutch is used to prevent the shift shock from occurring. Is set. Therefore, when the hydraulic pressure is constantly supplied to the friction engagement device for engine brake due to an electrical failure or the like, and the friction engagement device for engine brake is always engaged when setting the low speed stage, this low speed When performing a shift between a gear and another gear, the frictional engagement device for engine braking must be engaged or released at an appropriate timing. However, since it is difficult to control the timing of engagement and disengagement as described above, the one-way clutch is normally used to set the low speed stage, so the friction engagement device for engine braking cannot always engage. If so, the shift shock will inevitably increase.

Further, if the engine braking is always effective in the low speed stage, the braking force is always applied during coasting, so that the shock caused by such deceleration becomes large.

The present invention has been made in view of the above circumstances, and provides a control device in which a shock during traveling is not deteriorated even by a failure of a mechanism for supplying / discharging hydraulic pressure to / from a friction engagement device for engine braking. The purpose is that.

[0006]

In order to achieve the above object, the present invention is characterized in that it has a structure shown in FIG. 1 (A) or (B).

That is, FIG. 1A shows the structure of the invention described in claim 1. In the invention described in claim 1, the engine braking is effected by engaging at a predetermined gear. In the control device for the automatic transmission A, which selectively supplies the hydraulic pressure to the engine brake frictional engagement device 1 via the valve 3 controlled by the electric device 2, Fail detection means 4 for detecting a failure of at least one of the valves 3, and a shift for prohibiting the shift to the low speed stage when the failure detection means 4 detects a failure of the electrical means or the valve 3. It is characterized by being provided with a prohibiting means 5.

Further, FIG. 1B shows the structure of the invention described in claim 2. This invention is a friction for an engine brake for engaging the engine brake at a predetermined shift speed. In the control device for the automatic transmission A, which selectively supplies the hydraulic pressure to the engagement device 1 via the valve 3 controlled by the electric means 2, the electric means 2 and the valve 3 are connected. Fail detecting means 4 for detecting at least one fail; low speed determining means 6 for determining whether or not the set speed is the predetermined low speed.
When the failure of the electrical means 2 or the valve 3 is detected by the fail detection means 4 and the low speed stage determination means 6 determines that the low speed stage is set, the high speed stage other than the low speed stage is selected. It is characterized by comprising a shift command means 7 for upshifting.

[0009]

In the invention described in claim 1, the following shift control is performed. That is, when the valve 3 is controlled by the electric means 2 to send the hydraulic pressure to the engine brake frictional engagement device 1 when setting the predetermined low speed stage, the engine braking is effective at this low speed stage. When the electric means 2 or the valve 3 fails, for example, so as to maintain a state where the engine brake is applied, the fail detecting means 4 detects such a situation, and accordingly, the shift inhibiting means 5 causes the low speed stage to operate. Prohibit shifting to. As a result, a gear shift that involves switching between the engaged and released states of the engine brake frictional engagement device 1 does not occur, so that a large gearshift shock is prevented.

Further, in the invention described in claim 2, the fail detecting means 4 detects the fail of the valve 3 or the electric means 2 as described above, and at the same time, the set gear is the low speed. When the low speed stage determination means 6 determines that there is such a change, the shift command means 7 commands an upshift to a high speed stage. This high speed stage may be a gear stage where the engine brake works, but the engine braking state is not to be selectively set by engaging the engine brake friction engagement device 1, and therefore even if the engine braking works. However, since it does not result in excessive braking force, it is not felt as a so-called shock.

[0011]

1 is a block diagram schematically showing an embodiment of the present invention, in which an automatic transmission A connected to an engine E is shown. The output shaft of is the propeller shaft 10 and the final reduction gear 1
It is connected to the rear wheel axle 12 via 1 and drives the rear wheel 13. The engine E is configured to electrically control the fuel injection amount and the ignition timing, and an electronic control unit (E-ECU) 14 for controlling the engine E is mainly configured by a calculation element, a storage element, and an input / output interface. Various data such as throttle opening, water temperature, vehicle speed, and intake air temperature are input to the electronic control unit 14. Further, the automatic transmission A is configured to set each shift stage via an electric means such as a solenoid valve, and in order to control the shift, an electronic control unit (AE) is used.
CU) 15 is provided. The electronic control unit 15 is mainly composed of a calculation element, a storage element, and an input / output interface, and has an automatic shift according to a shift map stored in advance and a manual shift according to a manual signal input from the shift unit 16. And is supposed to do. Therefore, signals such as throttle opening, vehicle speed, brake signal, engine water temperature, pattern select signal, etc. and shift position signal and manual shift signal from the shift device 16 are input to the electronic control unit 15. This shift device 1
An example of No. 6 is shown in FIG. 2, and includes a parking (P) range, a reverse (R) range, a neutral (N) range, a drive (D) range, a second speed holding S range, and a first speed holding L range. The respective range positions are arranged in a straight line in the order listed here, and the first to fourth speed manual shift positions are arranged in an H-shape centering on the D range position. Switches (not shown) are provided at these manual shift positions, and when these switches are turned on by the shift lever, the signal is input to the electronic control unit 15. Further, the shift device 16 is connected to a hydraulic control device of the automatic transmission A via a link mechanism (not shown) for switching the manual valve. However, since the shift lever is moved from the D range position to the manual shift position, the manual valve is maintained in the D range state in the manual shift mode (manual mode). An example of the gear transmission and an example of the hydraulic circuit in the automatic transmission A will be described later.

Further, in the configuration shown in FIG. 2, an antilock brake system (ABS) is provided. That is, the ABS actuator 1 is attached to the front wheel 17 and the rear wheel 13.
8 is provided, and the ABS actuator 18 is connected to an electronic control unit (ABS).
-ECU) 19. Like the other electronic control devices 14 and 15, this electronic control device 19 is also mainly composed of an arithmetic element, a memory element, and an input / output interface, and the rotational speed of the four wheels and the vehicle body acceleration (G) sensor. A signal from (not shown) is input.

The automatic transmission electronic control unit 15 and the other two electronic control units 14 and 19 are connected so as to communicate data with each other.

An example of the gear transmission in the automatic transmission A described above is shown in FIG. 3, in which a torque converter 21 having a lockup clutch 20 and a second transmission section 30 having a set of planetary gear mechanisms. And a first speed change unit 40 that sets a plurality of forward gears and reverse gears by two sets of planetary gear mechanisms. The second transmission section 30 has
In order to perform high / low two-stage switching, the carrier 31 of the planetary gear mechanism is connected to the turbine runner 22 of the torque converter 21, and a clutch C0 is provided between the carrier 31 and the sun gear 32. The one-way clutch Fo and the one-way clutch Fo are provided in parallel with each other, and a brake B0 is provided between the sun gear 32 and the housing Hu.

The sun gears 41 and 42 in each planetary gear mechanism of the first transmission portion 40 are provided on a common sun gear shaft 43, and in the planetary gear mechanism on the left side (front side) in the drawing of the first transmission portion 40. Ring gear 44 and second
A first clutch C1 is provided between the gear unit 30 and the ring gear 33, and a second clutch C2 is provided between the sun gear shaft 43 and the ring gear 33 of the second gear unit 30. The carrier 45 of the planetary gear mechanism on the left side of the drawing and the ring gear 46 of the planetary gear mechanism on the right side (rear side) of the first transmission unit 40 are integrally connected, and
The output shaft 47 is attached to the carrier 45 and the ring gear 46.
Are connected.

The first brake B1 which is a band brake is provided on the outer peripheral side of the clutch drum of the second clutch C2 so as to stop the rotation of the sun gear shaft 43, more specifically, the sun gear shaft 43 and the housing. A first one-way clutch F1 and a second brake B2 are arranged in series with Hu, and a second one-way clutch F2 with a carrier 48 and a housing Hu in the planetary gear mechanism on the rear side. The third brake B3 is arranged in parallel.

A hydraulic circuit 50 for supplying and discharging hydraulic pressure to and from the clutches C0, C1 and C2 and the brakes B0, B1, B2 and B3 is provided. This hydraulic circuit 50
Is provided with first and second solenoid valves S1 and S2 for executing the first to fourth speed shifts, and a third solenoid valve S3 for engine braking.
These solenoid valves S1, S2, S3 are controlled to be turned on / off by the electronic control unit 15.

In the above-described automatic transmission A, each gear is set by engaging each friction engagement device as shown in FIG. In FIG. 4, a circle indicates ON for the solenoid valve, engagement for the friction engagement device, a cross for OFF for the solenoid valve, and release for the friction engagement device.

The above-described automatic transmission A can set the first speed to the fourth speed in the manual mode. In that case, the first speed and the second speed are different from the automatic mode.
It is necessary to apply the engine brake. Therefore, the hydraulic circuit shown in FIG. 5 is incorporated in the hydraulic control circuit 50 described above. The numbers circled in FIG. 5 indicate that the lines with the numbers are connected to each other.

The manual valve 100 switches the supply / discharge state of hydraulic pressure by moving the spool 101 by the shift device 16, and the line pressure P regulated by a primary regulator valve (not shown).
A line pressure oil passage 60 for supplying L is connected to the input port 102, and in the D range, the spool 101 is at the position shown in the figure so that the input port 102 communicates with the D port 103. In the S range, spool 10
1 moves to the lower side of the figure and the input port 102 is the D port 1
03 and S port 104, in the L range, the spool 101 moves further downward so that the input port 102 communicates with the D port 103, the S port 104 and the L port 105, and vice versa. Then, spool 101 closes input port 102, and in R range, input port 10
2 communicates with the R port 106, closes the input port 102 in the P range, and communicates other ports with the drain port.

The 1-2 shift valve 200 for shifting between the first speed and the second speed is a spool 2 having four lands.
01 and a spring 202 arranged at one end thereof, the control port 203 formed at the end opposite to the spring 202 is connected to the second solenoid valve S2, and when the second solenoid valve S2 is OFF. From the line pressure oil passage 61 to the strainer 62 and the orifice 63.
The line pressure PL supplied through the control port 203 is generated at the control port 203. Below the control port 203 in the drawing, a second coast port 204 that is opened and closed by the uppermost land, and a first brake port 206 that is selectively communicated with the second coast port 204 and the drain port 205 are sequentially arranged. The second coast modulator valve 64 is formed on the first brake port 206.
The first brake B1 is connected via. The manual valve 1 is located below the drain port 205 in the figure.
A D port 207 connected to the D port 103 of 00 is formed, and this D port 207 and another drain port 2
Second brake port 209 selectively connected to 08
The second brake B2 is connected to. Further another drain port 2 below the other drain port 208 in the drawing.
10 is formed, and the third brake B3 is connected to the third brake port 212 that selectively communicates with the drain port 210 and the low coast port 211. A hold port 213 is formed at the lowermost end where the spring 202 is arranged.

A 2-3 shift valve 300 for shifting between the second speed and the third speed has a spool 301 having six lands, and a spring 302 arranged at one end (lower end in the figure) of the spool 301. And a control port 303 formed at the end opposite to the spring 302 is connected to the first solenoid valve S1.
At the time of FF, the line pressure PL supplied from the D port 103 of the manual valve 100 through the strainer 65 and the orifice 66 is generated at the control port 303.

The 2-3 shift valve 300 includes a first drain port 304 and a brake port 3 in order from the top of the drawing.
05, the first D port 306 is formed, and the brake port 305 is connected to the second coast port 204 of the 1-2 shift valve 200, and the brake port 305 is connected to the first drain port 304 and the first drain port 304.
It is adapted to selectively communicate with the D port 306. Hold output port 30 following the above port
7, the input port 308, the clutch port 309, and the second drain port 310 are formed in order, and when the first drain port 304 and the brake port 305 are in communication, the first D port 306 and the hold output port 30.
7, the input port 308 and the clutch port 309 communicate with each other, and the brake port 305 is the first D port 30.
6, the hold output port 307 and the input port 308, and the clutch port 309 and the second drain port 310 are in communication with each other.
Further, a brake port 311 and a second D port 312 are sequentially formed following the second drain port 310, and when the clutch port 309 communicates with the input port 308, the second drain port 310 is connected to the brake port 311.
To the brake port 3 when the clutch port 309 communicates with the second drain port 310.
11 and the second D port 312 communicate with each other. Furthermore, a hold port 313 is formed at the lowermost end where the spring 302 is arranged.

The second clutch C2 is connected to the clutch port 309, while the 1-2 shift valve 2 is connected.
00 hold port 213 and this clutch port 30
9 and 9 are connected. Further, the brake port 311 is connected to the low coast port 211 of the 1-2 shift valve 200 via the low coast modulator valve 67. Further, the hold port 313 is connected to the L port 105 of the manual valve 100, and in the L range, the spool 301 is held at the pushed up position as shown in the right half of the figure.

The 3-4 shift valve 400 is controlled by the hydraulic pressure sent from the second solenoid valve S2 and the hold output port 307 of the 2-3 shift valve 300,
The second gear shifting unit 30 is configured to carry out gear shifting, and includes a spool 401 having four lands formed therein and a spring 402 arranged at one end thereof, and an end opposite to the spring 402. Control port 4 formed on
03 is connected to the second solenoid valve S2 similarly to the control port 203 of the 1-2 shift valve 200 described above, and the hold port 404 formed at the end where the spring 402 is arranged has a 2-3 shift. It is connected to the hold output port 307 of the valve 300. This 3-4 shift valve 400 has an input port 405 connected to the line pressure oil passage 61 when the second solenoid valve S2 is OFF and the line pressure PL is acting on the control port 403. , The brake B0 is connected to the connected brake port 406, and conversely, when the pressure is discharged from the control port 403 or when the hydraulic pressure acts on the hold port 404, the input port 4
05 is the clutch port 4 to which the clutch C0 is connected
It is designed to communicate with 07.

A first clutch C1 is connected to the D port 103 of the manual valve 100, and an oil passage extending from the first clutch C1 to the first and second D ports 306 and 312 of the 2-3 shift valve 300. In the middle of 68, in order to apply the engine braking in the first speed and the second speed in the manual mode, in other words, the coast for preventing the engine braking in the first speed and the second speed in the automatic mode. A brake cutoff valve 500 is provided. This selectively connects the clutch port 501 connected to the first clutch C1 and the brake port 502 connected to the first and second D ports 306 and 312 of the 2-3 shift valve 300. In addition, the hold port 505 which has the spool 504 which is pressed in one direction by the spring 503 and which is formed at the end portion where the spring 503 is arranged is connected to the S port 104 of the manual valve 100. A control port 506 formed at the opposite end is connected to the third solenoid valve S3. The third sonoid valve S3 connects the first clutch C1 and the control port 506 to the strainer 69 and the orifice 70.
Is connected to the oil passage 71, and the drain port is closed in the OFF state, and the line pressure P is applied to the control port 506.
When L is generated, the drain port is opened in the ON state to exhaust the pressure from the control port 506.

Each of the above solenoid valves S1, S2, S
Since 3 is turned on or off as shown in FIG. 4, in the 1-2 shift valve 200, the spool 201 is pushed down as shown in the right half at the first speed, and at other forward speeds, the spool 201 is not shown. In the 2-3 shift valve 300, the spool 301 is pushed up in the first and second gears as shown in the right half of the figure, and in the third and fourth gears, the spool 301 is pushed up. 301
Is pushed down as shown in the left half of the figure, and in the 3-4 shift valve 400, the spool 401 is pushed up as shown in the right half of the figure in the first to third speeds, and left in the figure in the fourth speed. Pushed down as shown in half. as a result,
Each friction engagement device is engaged or disengaged as shown in FIG. 4 to set each shift speed.

That is, in the automatic transmission A described above, the first
The third brake B3 is engaged to apply the engine brake at the speed, and the first brake B1 is engaged to apply the engine brake at the second speed, but the hydraulic pressure to these brakes B1 and B3 is applied. The coasting brake cutoff valve 500 is used to supply and discharge. And this coast brake cutoff valve 5
00 is connected to the hold port 505 of the S port 104 of the manual valve 100, so that the O of the third solenoid valve S3 is O in the S range and the L range.
The clutch port 501 and the brake port 502 are made to communicate with each other regardless of N / OFF. However, in the auto mode, the third solenoid valve S3 is turned off to shut off the clutch port 501 so that the engine braking does not work. I have to. Therefore, in the automatic mode in which the D range is selected, if the third solenoid valve S3 is constantly energized due to some electrical abnormality, engine braking will be activated in the first and second speeds of the D range. .. Therefore, when such a failure occurs, the apparatus shown in FIG. 2 controls as follows.

6 and 7 show the third solenoid valve S.
3 is a flow chart for explaining the shift control when 3 fails, first in step 1, input processing of various signals such as vehicle speed, throttle opening, shift position, auto mode signal, manual mode signal, etc., and then step In step 2, it is determined whether the shift position is in the D range. If the result of the determination is "yes", the process proceeds to step 3 to determine whether it is in the auto mode.
This means that in the shift device 16 shown in FIG. 2, the shift lever is set to the D range position and the signal accompanying it is output, or both of the switches provided in the manual shift position output the signal. It can be judged by not having.

If the result of the determination in step 3 is "yes", the process proceeds to step 4 and it is determined whether or not the third solenoid valve S3 is ON. In the auto mode in which the D range is selected, as shown in FIG.
Turn off the solenoid valve S3 and turn on the third brake B3.
The original control is to control so that the first brake B1 does not engage at the first speed or the second speed, but if the third solenoid valve S3 is ON, the third solenoid valve S3 is If the result of judgment in step 4 is “yes”, it means that it has failed.
After the flag F1 is set to "1" with, the process proceeds to step S6.

That is, the processes of steps 2 to 4 are processes for judging whether or not the third solenoid valve S3 has failed on the ON side, and for the sake of more accuracy, these processes should be performed. It may be repeated a plurality of times. After step 3, a process for determining whether or not the manual mode is set may be added to the margin of FIG. 6 as step 3a.

If it is determined that the third solenoid valve S3 is failing to the ON side, then in step 6, the shift diagram for failing is set.

FIG. 8 shows an example of a shift diagram set in the D range. (A) shows a normal shift, and (B) and (C) show a fail. That is, in the fail shift diagram shown in FIG. 8A, the upshift line and the downshift line between the first speed and the second speed and between the second speed and the third speed are set in the normal state. Is set to a lower speed side than in the shift diagram, and therefore, for example, when the vehicle is upshifted to the running state indicated by the point P in the drawing, the second speed is normally set, but the third speed is set when failing. ,
The gear is upshifted to a speed higher than normal and not engaging the first brake B1 and the third brake B3, which are frictional engagement devices for engine braking. On the other hand, the fail-time shift diagram shown in FIG. 8C omits the downshift lines of the third speed → the second speed and the second speed → the first speed. Therefore, if this shift diagram is selected, the second
Downshifting to first or first speed is prohibited.

After setting the shift diagram to the one for fail, the fuel cut is prohibited or restricted (step 7). This is because the electronic control unit 15 for the automatic transmission is transferred to the electronic control unit 14 for the engine, and the third solenoid valve S3
As shown in FIG. 9, the engine speed Ne for fuel cut during coast is set to Ne1 which is higher than the normal speed Ne2 as shown in FIG. It is done by changing. As a result, the fuel cut is not performed even in the traveling state in which the fuel cut is normally performed, so that the occurrence of the shock due to the fuel cut is prevented.

Further, in step 8, the ABS operation is prohibited. This is carried out by outputting a fail signal of the third solenoid valve S3 from the automatic transmission electronic control unit 15 to the ABS electronic control unit 19, and as a result, control interference is prevented.

Then, at step 9, control for releasing the lockup clutch 20 is performed. This is because the vibration absorption action of the torque converter 21 is sufficiently exerted. As this type of control, control may be adopted in which the engine speed at which the slip control of the lockup clutch 20 is started is changed to a higher speed than in normal times.

After the above-described measures against a failure are taken, in step 10, a shift judgment is made based on the selected shift map ((B) or (C) in FIG. 8) and the traveling state, and in step 11, the judgment is made. The signal for executing the shift to the selected gear is output.

If the third solenoid valve S3 has not failed, the result of the determination in step 4 is "NO". In that case, the process proceeds to step 12, and the shift map for normal operation, for example, FIG. (A) is set and the flag F1 is set to "0" (step 13).
After that, go to Step 10. That is, the gear shift is executed according to the gear shift diagram for the normal time.

If any manual shift position is selected by the shift device 16, step 3
Since the result of the determination is "No", the program proceeds to step 14 to determine the gear stage based on the output signal from the manual switch provided at the manual shift position of the shift device 16, and then proceeds to step 11 to shift gears. Output a signal to execute.

On the other hand, if the selected range is not the D range, the result of the determination in step 2 is "no", so the operation proceeds to step 15 and it is determined whether or not the S range is selected. If the result is "yes",
It is determined whether the flag F1 is set to "1" (step 16). If the flag F1 is "1", the third
Since the solenoid valve S3 has failed to the ON side, in this case, the process proceeds to step 17 to set the gear shift diagram for the time of failure.

FIG. 10 shows an example of a gear shift diagram for the S range, where (A) is for a normal state, and (B) and (C) are for a failed state. That is, the fail gear shift diagram shown in (B) of FIG. 10 is obtained by shifting the upshift line and the downshift line to the low speed side. Therefore, in the traveling state shown by the point Q in the diagram, the second gear is normally used. Although the speed is high, the speed becomes the third speed at the time of failure, which is higher than the normal speed and is the first brake B1 which is a friction engagement device for engine braking.
The gear is upshifted to a gear position where the third brake B3 is not engaged. On the other hand, the fail shift line diagram shown in FIG. 10C does not include the downshift line.
Therefore, when this shift diagram is selected, once the third speed is set, it is not set to the shift speed lower than that.

After setting the shift diagram as described above, the control process proceeds from step 7 to step 11,
The same control as when failing in the D range auto mode is performed.

In the S range, the third solenoid valve S
If 3 is not failed, the judgment result of step 16 is "No", and in this case, the process proceeds to step 18 and the shift map for normal operation in the S range, for example, the shift line of FIG. A diagram is set, and gear shifting is executed based on this (steps 10 and 11).

When a range other than the D range and the S range is selected, the result of the determination in step 15 is "No", so the routine proceeds to step 19 and it is determined whether or not the L range is selected. If the judgment result is "no", the control process returns, and if "yes", the process proceeds to step 20 to select the L range shift diagram, and then proceeds to step 10 and step 11 in order. That is, in the L range, the engine brake is applied at both the first speed and the second speed, so there is no particular problem in the L range even if the third solenoid valve S3 fails to the ON side. In this case, no measures are taken especially when the third solenoid valve S3 fails.

Therefore, if the third solenoid valve S3 fails to turn on and the engine braking is always effective in the first speed and the second speed by performing the above control, the vehicle travels in the first speed or the second speed. Is restricted as much as possible, and downshifting to the first speed or the second speed is restricted or prohibited. Therefore, a gear shift shock caused by a failure such that the third solenoid valve S3 is held in the ON state. And shocks due to excessive braking while driving are prevented.

In the control shown in FIGS. 6 and 7, if it is determined that the third solenoid valve S3 has failed to the ON side, the gear shift diagram is changed to shift to the first speed or the second speed. However, instead of such control, it is possible to forcibly upshift to the third speed or the fourth speed. Specifically, in step 6 described above, instead of setting the gear shift diagram for the fail time, it is set to a state in which a signal for shifting to the third speed or the fourth speed is output,
In step 11, the shift signal is output. As such a shift signal, a signal output from the third speed manual switch or the fourth speed manual switch can be adopted. Further, in step 17 described above, instead of setting the gear shift diagram for the fail time,
The speed change signal is set to be output in advance, and the speed change signal is output in step 11. As such a shift signal, a signal output from the third speed manual switch can be adopted.

In the above embodiment, the control such as prohibition of the first speed and the second speed is performed based on the failure of the third solenoid valve S3. However, in the present invention, the coast brake cutoff valve is controlled. It may be configured to detect a failure and perform the above-described shift inhibition control to the first speed or the second speed.

Further, the automatic transmission to which the present invention is applied is not limited to the ones shown in the above embodiments, but may be a gear transmission other than the gear transmission shown in FIG. 3 or shown in FIG. It can also be implemented for an automatic transmission provided with a hydraulic circuit other than the hydraulic circuit.

[0049]

As described above, according to the control device of the present invention, when a failure occurs in which the engine brake is constantly applied in the low speed stage where the engine brake is selectively applied, the shift to the low speed stage is performed. Not be set, or the lower gear will not be set, but the higher gear will be set.Therefore, gear shock or excessive braking will be caused by the engagement of the friction engagement device for engine braking. It is possible to prevent a shock due to being stowed and improve riding comfort.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention.

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

FIG. 3 is a skeleton diagram showing the gear transmission.

FIG. 4 is an operation table.

FIG. 5 is a hydraulic circuit diagram showing a main part of a hydraulic control device.

FIG. 6 is a flowchart showing a part of a control routine at the time of failure.

FIG. 7 is a flowchart showing another part of the control routine at the time of failure.

FIG. 8 is a gear shift diagram for a normal range and a fail range in the D range.

FIG. 9 is a map for fuel cut.

FIG. 10 is a gear shift diagram for a normal time and a fail time in the S range.

[Explanation of symbols]

 1 Engine Brake Friction Engaging Device 2 Electrical Means 3 Valve 4 Fail Detecting Means 5 Gear Change Prohibiting Means 6 Low Speed Determining Means 7 Gear Change Command Means A Automatic Transmission

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Okada 1 Toyota-cho, Toyota-shi, Aichi Toyota Automobile Co., Ltd. (72) Inventor Takeshi Inukazuka 10 Takane, Fujii-cho, Aichi-ken Aisin A / Dubliyu Incorporated (72) Inventor Masashi Hattori 10 Takane, Fujii-cho, Anjo City, Aichi Prefecture

Claims (2)

[Claims] 1. An automatic system for selectively supplying hydraulic pressure to an engine brake frictional engagement device for engaging an engine brake by engaging at a predetermined shift speed through a valve controlled by electrical means. In a transmission control device, a fail detecting means for detecting a fail of at least one of the electric means and the valve, and a case where the fail detecting means detects a fail of the electric means or the valve, A control device for an automatic transmission, comprising: a shift inhibiting means for inhibiting a shift to a low speed stage. 2. An automatic system for selectively supplying hydraulic pressure to a friction engagement device for an engine brake, which engages at a predetermined speed to apply an engine brake, through a valve controlled by electrical means. In a transmission control device, a fail detection unit that detects a failure of at least one of the electrical unit and the valve, and a low speed that determines whether or not a set speed is the predetermined low speed. When the low speed stage determination means determines that the failure of the electrical means or the valve is detected by the fail detection means and the low speed stage is set, a high speed stage other than the low speed stage A control device for an automatic transmission, comprising: a shift command means for upshifting to a next gear.