JP6895592B2 - Control device for automatic transmission and control method for automatic transmission - Google Patents

Description

The present invention relates to a control device for an automatic transmission mounted on a vehicle and a control method for the automatic transmission.

Conventionally, there is known an automatic transmission control device capable of ensuring the degree of freedom of the shift stage at the time of neutral fail (see Patent Document 1). This device was calculated from the rotation speed of the input shaft Input calculated using the rotation speed detection values from the first and second turbine rotation speed sensors and the rotation speed of the output shaft Output by the output shaft rotation speed sensor. Based on the gear ratio, it is determined that the vehicle is in a neutral failure state. When it is determined that the vehicle is in a neutral failure state, the neutral control for shifting to a safe gear is executed. The neutral control means erroneously releases the friction element or the friction element based on the selection gear stage for specifying the fastening friction element and the rotation speed relationship detected by the first and second turbine rotation speed sensors. Identify the actuator member to drive.

In the above-mentioned conventional device, when trying to identify the friction element of the release failure based on the rotation speed relationship detected by the selected gear stage and the turbine rotation speed sensor, it is released when there are a plurality of friction elements fastened in the selected gear stage. It may not be possible to identify the faulty part. On the other hand, if the gears are changed in order from the 1st gear while the vehicle is stopped, the rotation speed relationship is monitored at each gear, and the search control is performed to identify the release failure part, the identification of the release failure part is delayed. There was a problem that it was not possible to evacuate to a speed change stage that could travel quickly.

Japanese Unexamined Patent Publication No. 2008-2553

The present invention has been made by paying attention to the above problem, and when a release failure occurs in a friction element of an automatic transmission, the release failure portion is quickly identified, so that the gear can be quickly moved to a speed change stage. The purpose is.

In order to achieve the above object, the automatic transmission of the present invention includes an automatic transmission, a control valve unit, and a transmission control unit.
The transmission control unit corresponds to a release failure when any one of the plurality of friction elements has a release failure, and detects the rotation speed of the automatic transmission when a predetermined shift stage is selected. If the value is monitored and the rotation speed detection value deviates from the rotation speed target value of the selected transmission speed, it is determined that one of the fastening friction elements fastened at the selected transmission speed is a release abnormality. To do. At the time of release abnormality determination, the oil pressure detection value of the fastening friction element to be fastened at the selected shift stage is monitored, and if it is determined that the oil pressure detection value is lower than the normal oil pressure, the determined friction element is released. Specify as. When the release failure friction element is identified, fail-safe control is executed to shift to the evacuation shift stage that does not use the release failure friction element.

In this way, not only the determination is performed only while the vehicle is stopped, but also a measure for identifying the open failure friction element is adopted without performing the search control that takes time to identify the failure part. As a result, when a release failure occurs in the friction element of the automatic transmission, the release failure portion can be quickly identified, so that the transmission can be quickly retracted to a speed changeable stage.

FIG. 5 is an overall system diagram showing an engine vehicle equipped with an automatic transmission to which the control device and the control method of the first embodiment are applied. It is a skeleton diagram which shows an example of the automatic transmission to which the control device and the control method of Example 1 are applied. It is a fastening table diagram which shows the fastening state at each shift stage of the friction element for shifting in the automatic transmission to which the control device and the control method of Example 1 are applied. FIG. 5 is a shift map diagram showing an example of a shift map in an automatic transmission to which the control device and the control method of the first embodiment are applied. It is a control system block diagram which shows the detailed structure of the control valve unit and AT control unit of Example 1. FIG. It is a flowchart which shows the flow of the release failure fail-safe control processing of the 3rd clutch executed by the release failure fail-safe control part of the AT control unit of Example 1. FIG. It is a failure grade diagram which shows the failure mode, the cause, SOL, the AT influence immediately after the failure, and the vehicle behavior in the comparative example. FIG. 5 is a failure grade diagram showing a failure mode, a factor, a SOL, an AT effect immediately after a failure, and vehicle behavior in the first embodiment. It is a time chart which shows each characteristic which explains the fail-safe control action at the time of the running abnormality (other than contamination stick) of the line pressure solenoid in Example 1. FIG. It is a time chart which shows each characteristic which explains the fail-safe control action at the time of the running abnormality (other than contamination stick) of the lubrication solenoid in Example 1. FIG.

Hereinafter, embodiments for implementing the control device and control method for the automatic transmission of the present invention will be described with reference to Example 1 shown in the drawings.

The control device and control method in the first embodiment are applied to an engine vehicle (an example of a vehicle) equipped with an automatic transmission having 9-speed forward and 1-speed reverse gears. Hereinafter, the configuration of the first embodiment is divided into "overall system configuration", "detailed configuration of automatic transmission", "detailed configuration of hydraulic / electronic control system", and "third clutch release failure fail-safe control processing configuration". I will explain.

[Overall system configuration]
FIG. 1 is an overall system diagram showing an engine vehicle equipped with an automatic transmission to which the control device and the control method of the first embodiment are applied. Hereinafter, the overall system configuration will be described with reference to FIG.

As shown in FIG. 1, the drive system of the engine vehicle includes an engine 1, a torque converter 2, an automatic transmission 3, a propeller shaft 4, and drive wheels 5. A spool valve for shifting, a hydraulic control circuit, a solenoid valve, and a control valve unit 6 are attached to the automatic transmission 3. The actuators (clutch solenoid 20, line pressure solenoid 21, lubrication solenoid 22, lockup solenoid 23) included in the control valve unit 6 operate in response to a control command from the AT control unit 10. Here, a plurality of clutch solenoids 20 are provided for each friction element. The torque converter 2 has a built-in lockup clutch 2a that directly connects the crankshaft of the engine 1 and the input shaft IN of the automatic transmission 3 by fastening.

As shown in FIG. 1, the control system of the engine vehicle includes an AT control unit 10, an engine control unit 11, and a CAN communication line 12. The AT control unit 10 has a release failure fail-safe control unit 10a.

The AT control unit 10, which is a control device for the automatic transmission 3, includes a turbine rotation sensor 13, an output shaft rotation sensor 14, an ATF oil temperature sensor 15, an inhibitor switch 18, an intermediate shaft rotation sensor 19, a third clutch pressure sensor 24, and a line. A signal from the pressure sensor 25 or the like is input.

The turbine rotation sensor 13 detects the turbine rotation speed (= transmission input shaft rotation speed) of the torque converter 2 and sends a signal of the turbine rotation speed Nt to the AT control unit 10. The output shaft rotation sensor 14 detects the output shaft rotation speed (= vehicle speed) of the automatic transmission 3 and sends a signal of the output shaft rotation speed No (vehicle speed VSP) to the AT control unit 10. The ATF oil temperature sensor 15 detects the temperature of the ATF (oil for automatic transmission fluid) and sends a signal of the ATF oil temperature TATF to the AT control unit 10. The inhibitor switch 18 detects the range position selected by the driver's select operation on the select lever, select button, or the like, and sends a range position signal to the AT control unit 10. The intermediate shaft rotation sensor 19 detects the rotation speed of the intermediate shaft (intermediate shaft = rotating member connected to the first carrier C1), and sends a signal of the intermediate shaft rotation speed Nint to the AT control unit 10.

The third clutch pressure sensor 24 detects the oil pressure in the clutch oil chamber of the third clutch K3, which will be described later, and sends a third clutch pressure signal to the AT control unit 10. The line pressure sensor 25 detects the line pressure PL adjusted by the control valve unit 6 and sends a line pressure signal to the AT control unit 10.

The AT control unit 10 monitors changes in the driving point (VSP, APO) due to the vehicle speed VSP and the accelerator opening APO on the shift map (see FIG. 4).
1. Auto upshift (due to vehicle speed increase while maintaining accelerator opening)
2. Foot release upshift (by accelerator foot release operation)
3. Foot return upshift (by accelerator return operation)
4. Power on / downshift (due to a decrease in vehicle speed while maintaining the accelerator opening)
5. Small opening sudden downshift (depending on the small amount of accelerator operation)
6. Large opening sudden downshift (depending on the amount of accelerator operation: "kickdown")
7. Slow downshift (due to slow accelerator operation and increased vehicle speed)
8. Coast downshift (due to a decrease in vehicle speed when the accelerator is released)
Shift control is performed according to a basic shift pattern called.

The engine control unit 11 inputs signals from the accelerator opening sensor 16, the engine rotation sensor 17, and the like.

The accelerator opening sensor 16 detects the accelerator opening caused by the driver's accelerator operation, and sends a signal of the accelerator opening APO to the engine control unit 11. The engine rotation sensor 17 detects the rotation speed of the engine 1 and sends a signal of the engine rotation speed Ne to the engine control unit 11.

In the engine control unit 11, in addition to various controls of the engine itself, engine torque limit control and the like are performed by coordinated control with the control of the AT control unit 10. The AT control unit 10 and the engine control unit 11 are connected via a CAN communication line 12 capable of exchanging information in both directions. Therefore, when an information request is input from the AT control unit 10, the engine control unit 11 transmits information on the accelerator opening APO, engine speed Ne, engine torque Te, and turbine torque Tt to the AT control unit 10 in response to the request. Output. Further, when an engine torque limit request based on the upper limit torque is input from the AT control unit 10, engine torque limit control is executed in which the engine torque is limited by a predetermined upper limit torque.

[Detailed configuration of automatic transmission]
FIG. 2 is a skeleton diagram showing an example of the automatic transmission 3 to which the control device and the control method of the first embodiment are applied, FIG. 3 is a fastening table for the automatic transmission 3, and FIG. 4 is an automatic transmission 3 An example of the shift map in is shown. Hereinafter, the detailed configuration of the automatic transmission 3 will be described with reference to FIGS. 2 to 4.

The automatic transmission 3 is characterized by the following points.
(a) A one-way clutch that mechanically engages / idles is not used as a shifting element.
(b) The first brake B1, the second brake B2, the third brake B3, the first clutch K1, the second clutch K2, and the third clutch K3, which are friction elements, are independently engaged / released by the clutch solenoid 20 at the time of shifting. Is controlled.
(b) The second clutch K2 and the third clutch K3 have a centrifugal canceling chamber that cancels the centrifugal pressure due to the centrifugal force acting on the clutch piston oil chamber.

As shown in FIG. 2, the automatic transmission 3 has, as planetary gears constituting the gear train, the first planetary gear PG1, the second planetary gear PG2, and the third planet in order from the input shaft IN to the output shaft OUT. It is equipped with a gear PG3 and a fourth planetary gear PG4.

The first planetary gear PG1 is a single pinion type planetary gear, and has a first sun gear S1, a first carrier C1 that supports a pinion that meshes with the first sun gear S1, and a first ring gear R1 that meshes with the pinion.

The second planetary gear PG2 is a single pinion type planetary gear, and has a second sun gear S2, a second carrier C2 that supports a pinion that meshes with the second sun gear S2, and a second ring gear R2 that meshes with the pinion.

The third planetary gear PG3 is a single pinion type planetary gear, and has a third sun gear S3, a third carrier C3 that supports a pinion that meshes with the third sun gear S3, and a third ring gear R3 that meshes with the pinion.

The fourth planetary gear PG4 is a single pinion type planetary gear, and has a fourth sun gear S4, a fourth carrier C4 that supports a pinion that meshes with the fourth sun gear S4, and a fourth ring gear R4 that meshes with the pinion.

As shown in FIG. 2, the automatic transmission 3 includes an input shaft IN, an output shaft OUT, a first connecting member M1, a second connecting member M2, and a transmission case TC. As friction elements that are engaged / released by shifting, the first brake B1, the second brake B2, the third brake B3, the first clutch K1, the second clutch K2, and the third clutch K3 are provided. There is.

The input shaft IN is a shaft in which the driving force from the engine 1 is input via the torque converter 2, and is always connected to the first sun gear S1 and the fourth carrier C4. The input shaft IN is connected to the first carrier C1 via the second clutch K2 so as to be connectable and detachable.

The output shaft OUT is a shaft that outputs the drive torque shifted to the drive wheels 5 via the propeller shaft 4 and the final gear (not shown), and is always connected to the third carrier C3. The output shaft OUT is connected to the fourth ring gear R4 via the first clutch K1 so as to be connectable and disconnectable.

The first connecting member M1 is a member that constantly connects the first ring gear R1 of the first planetary gear PG1 and the second carrier C2 of the second planetary gear PG2 without interposing a friction element. The second connecting member M2 always connects the second ring gear R2 of the second planetary gear PG2, the third sun gear S3 of the third planetary gear PG3, and the fourth sun gear S4 of the fourth planetary gear PG4 without interposing a friction element. It is a member to do.

The first brake B1 is a friction element capable of locking the rotation of the first carrier C1 with respect to the transmission case TC. The second brake B2 is a friction element capable of locking the rotation of the third ring gear R3 with respect to the transmission case TC. The third brake B3 is a friction element capable of locking the rotation of the second sun gear S2 with respect to the transmission case TC.

The first clutch K1 is a friction element that selectively connects the fourth ring gear R4 and the output shaft OUT. The second clutch K2 is a friction element that selectively connects the input shaft IN and the first carrier C1. The third clutch K3 is a friction element that selectively connects between the first carrier C1 and the second connecting member M2.

FIG. 3 shows a fastening table that achieves forward 9th speed and backward 1st speed in the D range by combining three simultaneous fastenings out of the six friction elements in the automatic transmission 3. Hereinafter, a shift configuration for establishing each shift stage will be described with reference to FIG.

The first speed (1st) is achieved by simultaneously engaging the second brake B2, the third brake B3, and the third clutch K3. The second speed (2nd) is achieved by simultaneously engaging the second brake B2, the second clutch K2, and the third clutch K3. The third speed (3rd) is achieved by simultaneously engaging the second brake B2, the third brake B3, and the second clutch K2. The 4th speed (4th) is achieved by simultaneously engaging the second brake B2, the third brake B3, and the first clutch K1. The fifth speed (5th) is achieved by simultaneously engaging the third brake B3, the first clutch K1 and the second clutch K2. The above 1st to 5th gears are underdrive gears with a reduction gear ratio in which the gear ratio exceeds 1.

The 6th speed (6th) is achieved by simultaneously engaging the first clutch K1, the second clutch K2, and the third clutch K3. This sixth speed stage is a directly connected stage having a gear ratio of 1.

The 7th speed (7th) is achieved by simultaneously engaging the 3rd brake B3, the 1st clutch K1 and the 3rd clutch K3. The 8th speed (8th) is achieved by simultaneously engaging the first brake B1, the first clutch K1, and the third clutch K3. The 9th speed stage (9th) is achieved by simultaneously engaging the first brake B1, the third brake B3, and the first clutch K1. The 7th to 9th speeds are overdrive speeds with an increasing gear ratio of less than 1.

Further, among the 1st to 9th gears, when the upshift is performed to the adjacent gears or the downshift is performed, as shown in FIG. 3, the shift is changed. .. That is, the shift to the adjacent shift stage is achieved by releasing one friction element and fastening one friction element while maintaining the fastening of two friction elements among the three friction elements. ..

The reverse speed stage (Rev) by selecting the R range position is achieved by simultaneously engaging the first brake B1, the second brake B2, and the third brake B3. When the N range position and the P range position are selected, all six friction elements B1, B2, B3, K1, K2, and K3 are released.

A shift map as shown in FIG. 4 is stored and set in the AT control unit 10, and the shift by switching the shift stage from the 1st speed to the 9th speed on the forward side by selecting the D range is performed. It is done according to the shift map. That is, when the operating point (VSP, APO) at that time crosses the upshift line shown by the solid line in FIG. 4, an upshift shift request is issued. Further, when the operating point (VSP, APO) crosses the downshift line shown by the broken line in FIG. 4, a downshift shift request is issued.

[Detailed configuration of hydraulic / electronic control system]
FIG. 5 shows a detailed configuration of the control valve unit 6 and the AT control unit 10 of the first embodiment. Hereinafter, the detailed configuration of the hydraulic / electronic control system will be described with reference to FIG.

The control valve unit 6 includes a mechanical oil pump 61 and an electric oil pump 62 as hydraulic sources. The mechanical oil pump 61 is pump-driven by the engine 1, and the electric oil pump 62 is pump-driven by the electric motor 63.

The control valve unit 6 includes a line pressure solenoid 21, a line pressure regulating valve 64, a clutch solenoid 20, and a lockup solenoid 23 as valves provided in the flood control circuit. Further, it includes a lubrication solenoid 22, a lubrication pressure regulating valve 65, a boost switching valve 66, a P-nP switching valve 67, and a cooler 68.

The line pressure adjusting valve 64 regulates the discharged oil from at least one of the mechanical oil pump 61 and the electric oil pump 62 to the line pressure PL based on the valve operating signal pressure from the line pressure solenoid 21.

The clutch solenoid 20 uses the line pressure PL as the original pressure and controls the fastening pressure, the releasing pressure, and the like for each of the friction elements B1, B2, B3, K1, K2, and K3. Although it is described that there is one clutch solenoid 20 in FIG. 5, it has six solenoids for each friction element B1, B2, B3, K1, K2, K3.

The lockup solenoid 23 controls the differential pressure of the lockup clutch 2a by using excess oil at the time of adjusting the line pressure PL by the line pressure adjusting valve 64.

The lubrication solenoid 22 creates a valve operating signal pressure to the lubrication pressure regulating valve 65, a switching pressure to the boost switching valve 66, and a switching pressure to the P-nP switching valve 67.

The lubrication pressure regulating valve 65 can control the lubrication flow rate supplied to the power train (PT) including the friction element and the gear train via the cooler 68 by the valve operating signal pressure from the lubrication solenoid 22. Then, friction is reduced by optimizing the PT supply lubrication flow rate by the lubrication pressure regulating valve 65.

The boost switching valve 66 increases the amount of oil supplied to the centrifugal cancel chambers of the second clutch K2 and the third clutch K3 by the switching pressure from the lubrication solenoid 22. This boost switching valve 66 is used when the amount of oil supplied is temporarily increased in a scene where the amount of oil in the centrifugal cancel chamber is insufficient.

The P-nP switching valve 67 switches the oil passage of the line pressure supplied to the parking module by the switching pressure from the lubrication solenoid 22, and performs park clock.

As described above, the control valve unit 6 is characterized in that a shift-by-wire structure is adopted and the manual valve for switching the D-range pressure oil passage, the R-range pressure oil passage, or the like is abolished. It also includes a lubrication solenoid 22, a lubrication pressure regulating valve 65, a boost switching valve 66, and a P-nP switching valve 67, which are unique valve elements.

As shown in FIG. 5, the AT control unit 10 has a release failure fail-safe corresponding to a release failure when any one of a plurality of friction elements B1, B2, B3, K1, K2, and K3 has a release failure. It has a control unit 10a.

The release failure fail-safe control unit 10a monitors the rotation speed detection value of the automatic transmission 3 when a predetermined gear is selected, and the rotation speed detection value is the rotation speed target value of the selected gear. If it deviates from the above, it is determined that any of the fastening friction elements fastened at the selected shift stage is a release abnormality. At the time of release abnormality determination, the oil pressure detection value of the fastening friction element to be fastened at the selected shift stage is monitored, and if it is determined that the oil pressure detection value is lower than the normal oil pressure, the determined friction element is released. Specify as. When the release failure friction element is identified, fail-safe control is executed to shift to the evacuation shift stage that does not use the release failure friction element.

The release failure fail-safe control unit 10a monitors the gear ratio detection value of the automatic transmission 3 during traveling in which a predetermined shift stage is selected. Then, when the gear ratio detection value deviates from the gear ratio target value of the selected gear ratio, it is determined that any of the fastening friction elements fastened at the selected gear ratio is a release abnormality.

The release failure fail-safe control unit 10a regulates the upper limit of the input torque to the automatic transmission 3 when the accelerator is released while the vehicle is stopped when a predetermined shift stage is selected. Then, the difference rotation speed between the input rotation speed detection value and the input rotation speed target value of the automatic transmission 3 is monitored, and if the difference rotation speed exceeds a predetermined value and deviates, the engine is fastened at the selected shift stage. It is determined that any of the fastening friction elements to be operated is an abnormal release.

The release failure fail-safe control unit 10a outputs a oil pressure increase command to the line pressure solenoid 21 when it is determined that the oil pressure detection value is normal at the time of the release abnormality determination. While searching for the line pressure after outputting the oil pressure rise command, the process shifts to the shift stage of the evacuation destination that uses the friction element determined to have the normal oil pressure detection value. When the shift speed of the save destination is selected, the rotation speed detection value of the automatic transmission 3 is monitored, and it is determined that the rotation speed detection value deviates from the rotation speed target value of the shift speed of the save destination. Moreover, when it is determined that the line pressure is abnormal by the line pressure search after outputting the oil pressure rise command, the line pressure solenoid 21 is specified as a failure part. When the line pressure solenoid 21 is identified as a failure site, fail-safe control that limits the upper limit of the input torque (engine torque) to the automatic transmission 3 is executed.

The release failure fail-safe control unit 10a monitors the rotation speed detection value of the automatic transmission 3 when the shift speed of the save destination is selected, and the rotation speed detection value is the rotation speed target value of the shift stage of the save destination. If it is determined that the line pressure deviates from the above and the line pressure is determined to be normal by the line pressure search after outputting the oil pressure rise command, the lubrication solenoid 22 is specified as a failure part. When the lubrication solenoid 22 is identified as a failure site, a fail-safe control for shifting to an evacuation shift stage that does not use the friction element determined to have a normal oil pressure detection value is executed.

[3rd clutch release failure fail-safe control processing configuration]
FIG. 6 shows the flow of the release failure fail-safe control process of the third clutch K3 executed by the release failure fail-safe control unit 10a of the AT control unit 10 of the first embodiment. Hereinafter, each step of FIG. 6 will be described. In the first embodiment, the release failure fail-safe control processing configuration of the third clutch K3 is shown, but the other friction elements B1, B2, B3, K1 and K2 are also provided with the same processing configuration by providing each hydraulic sensor. can do.

In step S1, following the determination that there is no determination in the start or S3 or S5, it is determined whether or not there is a gear ratio deviation determination. If there is a gear ratio deviation determination, the process proceeds to step S2, and if there is no gear ratio deviation determination, the process proceeds to the end.

Here, when determining the gear ratio deviation, the turbine rotation speed Nt (= transmission input shaft rotation speed) from the turbine rotation sensor 13 and the output shaft rotation speed No. from the output shaft rotation sensor 14 are input. Then, while traveling with the predetermined gear ratio selected, the gear ratio detection value (= Nt / No) of the automatic transmission 3 is monitored, and the gear ratio detection value is the gear ratio target value of the selected gear ratio. If there is a deviation of ± a predetermined value or more from, it is considered that there is a gear ratio deviation judgment. On the other hand, the upper limit of the input torque to the automatic transmission 3 is regulated when the accelerator is released while the vehicle is stopped when a predetermined shift stage is selected. Then, the difference rotation speed between the input rotation speed detection value (turbine rotation speed Nt) of the automatic transmission 3 and the input rotation speed target value (output shaft rotation speed No × target gear ratio) is monitored, and the difference rotation speed is a predetermined value. If there is a divergence beyond, it is considered that there is a gear ratio divergence judgment.

In step S2, following the determination that there is a gear ratio deviation determination in S1, the cumulative timer is counted and the process proceeds to step S3.

In step S3, following the cumulative timer count in S2, the cumulative timer determines whether or not the predetermined timer value has been determined to be reached. If the cumulative timer has reached the predetermined timer value, the process proceeds to step S4, and if the cumulative timer does not reach the predetermined timer value, the process returns to step S1.

In step S4, following the determination that the cumulative timer in S3 has reached the predetermined timer value, the cumulative timer determination number is increased, and the process proceeds to step S5.

In step S5, following the failure notification of the lubrication solenoid 22 in S4, it is determined whether or not the cumulative timer determination number has reached the predetermined number. If the cumulative timer determination number of times has reached the predetermined number of times, the process proceeds to step S6, and if the cumulative timer determination number of times has not reached the predetermined number of times, the process returns to step S1.

In step S6, following the determination that the cumulative timer determination number in S5 has reached the predetermined number of times, any of the fastening friction elements (including the third clutch K3) at the shift stage selected at that time It is confirmed that the release is abnormal, and the process proceeds to step S7.

In step S7, following the determination of the release abnormality in S6, it is determined whether or not the oil pressure of the third clutch K3 is normal. If it is lower than normal, it is presumed that the third clutch K3 has slipped and the process proceeds to step S8. If it is normal, it is presumed that the third clutch K3 has slipped and the process proceeds to step S9.

Here, in determining whether or not the oil pressure of the third clutch K3 is normal, the oil pressure detection value of the third clutch K3 from the third clutch pressure sensor 24 is equal to or greater than the release determination threshold value than the oil pressure based on the line pressure command value. If it is low, it is determined that the oil pressure of the third clutch K3 is lower than normal.

In step S8, following the determination that the oil pressure of the third clutch K3 in S7 is lower than normal, the shift stage is shifted to the evacuation destination shift stage when the third clutch K3 is erroneously released, and the process proceeds to the end.

Here, the evacuation destination gear when the third clutch K3 is erroneously released is a gear that does not use the third clutch K3 (3rd gear, 4th gear, 5th gear, 9th gear: see FIG. 3). Therefore, considering the limp home property, it is one of the 3rd speed, 4th speed, and 5th speed.

In step S9, following the determination that the oil pressure of the third clutch K3 in step S7 is normal, a control command for increasing the line pressure PL is output to the line pressure solenoid 21, and the process proceeds to step S10.

In step S10, following the PL oil pressure increase in S9, it is determined whether or not the line pressure detection value detected by the line pressure sensor 25 is increased according to the increase command to the line pressure solenoid 21. If the PLSOL is normal, the process proceeds to step S11, and if the PLSOL is abnormal, the process proceeds to step S12.

In step S11, following the determination that PLSOL is normal in S10, the PLSOL normal result (plfailflag = 0) is stored, and the process proceeds to step S13.

In step S12, following the determination that the PLSOL is abnormal in S10, the PLSOL abnormality result (plfailflag = 1) is stored, and the process proceeds to step S13.

In step S13, following the memory of the result of PLSOL normal / abnormal in S10 or S11, when the torque upper limit is limited, the torque upper limit limit is released by diagonally raising and returning according to the increase in the accelerator opening APO, and the process proceeds to step S14. move on.

In step S14, following the release of the torque upper limit limit in S13, the process shifts to the shift stage of the evacuation destination using the third clutch K3, and the process proceeds to step S15.

Here, the evacuation destination shift stage using the third clutch K3 is a shift stage using the third clutch K3 (1st speed, 2nd speed, 6th speed, 7th speed, 8th speed: see FIG. 3). ), Which is the gear that is not selected at that time.

In step S15, following the shift to the gear ratio of the retracted destination in S14, it is determined whether or not there is a gear ratio deviation at the gear ratio of the retracted destination. If there is a gear ratio deviation determination (with gear ratio deviation), the process proceeds to step S17, and if there is no gear ratio deviation determination (no gear ratio deviation), the process proceeds to step S16. The presence or absence of the gear ratio deviation is determined in the same manner as in step S1.

In step S16, following the determination that there is no gear ratio deviation in S15, it is determined that the elements other than the third clutch K3 are erroneously released as determined in step S7, and the process proceeds to the end.

In step S17, following the determination that there is a gear ratio deviation in S15, the search result of the line pressure solenoid 21 in steps S10 to S12 is determined. If the PLSOL search result determination is plfailflag = 1, the process proceeds to step S18, and if the PLSOL search result determination is plfailflag = 0, the process proceeds to step S20.

In step S18, following the determination that the PLSOL search result determination in S17 is plfailflag = 1, the abnormality of the line pressure solenoid 21 is confirmed, and the process proceeds to step S19.

In step S19, following the determination of the PLSOL abnormality in S18, the torque upper limit value limit control (corresponding to C grade) is executed, and the process proceeds to the end.

In step S20, following the determination that the PLSOL search result determination in S17 is plfailflag = 0, the abnormality of the lubrication solenoid 22 is confirmed, and the process proceeds to step S21.

In step S21, following the determination of the lubrication SOL abnormality in S20, since the slip factor is a decrease in μ of the friction element, the shift stage is shifted to the evacuation destination shift stage that does not use the third clutch K3, and the process proceeds to the end. Here, the shift stages that do not use the third clutch K3 are the third speed stage, the fourth speed stage, the fifth speed stage, and the ninth speed stage (see FIG. 3).

Next, the actions of the first embodiment are described as "background technique", "fail-safe control action of friction element release failure", "fail-safe control action when line pressure solenoid is abnormal", and "fail-safe control action when lubrication solenoid is abnormal". Will be explained separately.

[Background technology]
In the automatic transmission unit targeted by the present invention, each of the friction elements involved in shifting is changed by a clutch solenoid, and it is necessary to study how to deal with a failure. The clutch solenoid function abnormality diagnosis was also performed for the existing automatic transmission unit, but there are new issues due to functional safety requirements and system differences, so we will also consider it.

Therefore, we decided to clarify the failure mode and incorporate the diagnosis and treatment of gear ratio dysfunction (release failure) accordingly. The following describes (1) self-diagnosis policy, (2) system overview, (3) failure mode, (4) failure grade, (5) requirement clarification, and (6) problem clarification.

(1) Self-diagnosis policy To be able to achieve the five requirements (safety assurance, legal compliance, false positive prevention, PT protection, and limp homeability assurance) that should be considered in self-diagnosis development.

(2) System overview (difference from existing units)
The automatic transmission unit targeted by the present invention adopts shift-by-wire and the manual valve is abolished. On the other hand, the existing automatic transmission unit had a hard guarantee of forward / backward movement with a manual valve, but there is a new failure mode because it does not have that function.

(3) Failure mode A clutch engagement and release failure including a valve hydraulic circuit failure (intermediate pressure) is assumed.
Since the release instruction SOL is premised on the state of being completely opened, it is considered that a failure on the gripping side does not occur suddenly due to a failure on the wrong fastening side. Misfastened side failure occurs triggered by shifting. Of the erroneous fastening side failures, the side failure that cannot be released is assumed to be a scene in which an interlock (A grade failure) occurs.

(4) Failure grade The failure grades of each failure mode of the clutch solenoid for shifting are summarized in FIG. 7. That is, in the case of an intermediate pressure of contamination, there is a risk of upgrading by changing the SOL instruction. This is because an intermediate clutch pressure is generated even if a faulty SOL is instructed to be engaged or released, and erroneous release and erroneous engagement are changed by the SOL instruction. If the failure that causes the same clutch slip due to the functional abnormality is extracted, the PLSOL functional abnormality and the lubrication SOL functional abnormality also cause the clutch slip, so it is necessary to consider the countermeasures together.

(5) Clarification of requirements Safety: Do not upgrade by dragging the clutch due to shifting (avoid grade A).
Limp Home: Downgrade from non-running (B grade) to runnable (C grade).
Unit protection: The highest priority is to avoid the mode that makes it impossible to drive (B grade) due to clutch burning.
In addition, priority is given to the current failure grade response over the failure grade that will occur in the future.

(6) Clarification of issues
(a) Judge the erroneous release function failure state during the fastening instruction.
(b) Identify the faulty part in order to move to the limp home due to a false release fault.
(c) In the event of an intermediate pressure failure in the contaminant, the failed SOL does not cause sudden deceleration by instructing release by switching gears.
(d) Prevent clutch burning due to clutch heat generation.
(e) Prevent upgrades due to interference with other failure factors of clutch slippage.

[Release of friction element Fail-safe control action]
The present invention has been made by paying attention to the problems extracted in the above (6) Problem clarification. As a means for solving the problem, the AT control unit 10 has a release failure fail-safe control corresponding to a release failure when any one of a plurality of friction elements B1, B2, B3, K1, K2, and K3 has a release failure. It has a part 10a. The release failure fail-safe control unit 10a monitors the rotation speed detection value of the automatic transmission 3 when a predetermined gear is selected, and the rotation speed detection value is the rotation speed target value of the selected gear. If it deviates from the above, it is determined that any of the fastening friction elements fastened at the selected shift stage is a release abnormality. At the time of release abnormality determination, the oil pressure detection value of the fastening friction element to be fastened at the selected shift stage is monitored, and if it is determined that the oil pressure detection value is lower than the normal oil pressure, the determined friction element is released. Specify as. When the release failure friction element is identified, a means for executing fail-safe control to shift to the evacuation shift stage without using the release failure friction element is adopted.

That is, when the release abnormality of any of the fastening friction elements to be fastened at the selected gear ratio is determined by the gear ratio deviation determination, in the flowchart of FIG. 8, S1 → S2 → S3 → S4 → S5 → S6 → S7. Proceed to. In S7, it is determined whether or not the oil pressure of the third clutch K3 is normal, and if it is lower than normal, it is estimated that the third clutch K3 has slipped, and the process proceeds to step S8. In step S8, a fail-safe control for shifting the shift gear to the retracted shift gear when the third clutch K3 is erroneously released is executed.

In this way, when a release failure occurs in the friction element of the automatic transmission 3, by promptly identifying the release failure portion, it is possible to quickly evacuate to a shift stage capable of traveling. That is, it is intended to determine the erroneous release function failure state during the fastening instruction, and when a predetermined shift stage is selected, the rotation speed detection value of the automatic transmission 3 and the oil pressure detection value of the friction element are monitored. I made it. Therefore, when identifying the faulty part, it is not limited to the time when the vehicle is stopped, and it is determined that any shift stage to which the three friction elements are fastened is selected even while the vehicle is running. Can be done. Then, it is a method of monitoring the rotation speed detection value and the oil pressure detection value in the selected shift stage, and since the search control that takes time to identify the release failure friction element is not performed, the failure occurs as compared with the search control. It is possible to shorten the time required to confirm the abnormality.

Incidentally, the failure grades of the failure modes of the clutch solenoid 20 for shifting in the first embodiment are summarized in FIG. That is, in the case of the instruction to fasten the contaminant / oil leak at the MIN pressure, the failure grade in the comparative example was that the vehicle could not run without the clutch capacity (B grade) as shown in FIG. On the other hand, the failure grade in the first embodiment is downgraded to normal running (normal) as shown in FIG.

In the case of an instruction to release the contaminant stick at an intermediate pressure, the failure grade in the comparative example was, as shown in FIG. 7, a large clutch drag, a slight interlock, and impossibility of running (A grade). On the other hand, as shown in FIG. 8, the failure grade in the first embodiment is downgraded to runnable (C grade) although the clutch slips and the driving force becomes insufficient.

[Fail-safe control action when line pressure solenoid is abnormal]
If the failure that causes the same clutch slip due to the malfunction is extracted, the PLSOL malfunction also causes the clutch slip, so the countermeasures were also examined.

That is, in the flowchart of FIG. 6, it is presumed that the oil pressure of the third clutch K3 is normal in S7 and the elements other than the third clutch K3 slip. In this case, control is performed to increase the line pressure PL from S7 to S9, and if the line pressure solenoid 21 is dysfunctional, the process proceeds from S9 to S10 → S12 → S13 → S14. In S14, the shift is made to the shift stage of the evacuation destination where the third clutch K3 is used. For example, when the 6th speed is selected, the speed shifts to the 7th speed as the evacuation destination of the third clutch K3.

After shifting to the shift destination of the evacuation destination using the third clutch K3 in S14, if it is determined in the next S15 that there is a gear ratio deviation, the process proceeds from S15 to S17 → S18 → S19 → end. In S18, it is determined that the line pressure solenoid 21 is abnormal, and in S19, torque upper limit value limit control (corresponding to C grade) is executed.

A time chart showing the fail-safe control action when the line pressure solenoid is abnormal is shown in FIG.

When a failure occurs in the line pressure solenoid 21 at time t1, the abnormality confirmation (small slip) timer rises, and when the predetermined value is reached at time t2, the abnormality is confirmed. When the line pressure PL starts to rise at time t3 after time t2 and the normal / abnormal determination of the line pressure solenoid 21 is completed at time t4, the speed of the automatic transmission 3 is changed to 6th speed from time t4. Shifts to 7th gear. Then, when the abnormality of the line pressure solenoid 21 is confirmed at time t5, the process shifts from no input torque limitation to with input torque limitation.

As described above, the line pressure solenoid 21 may be abnormal even if the third clutch pressure sensor 24 determines that the third clutch K3 is normal. Therefore, the line pressure PL may be changed. After raising it, determine whether the hydraulic pressure is working as intended. Then, when shifting to the shift stage of the evacuation destination using the third clutch K3, if there is a deviation in the gear ratio at the shift stage of the evacuation destination and the line pressure PL does not move as intended, the line pressure solenoid 21 is abnormal. Is confirmed. When the abnormality of the line pressure solenoid 21 is confirmed, the process shifts from no input torque limitation to with input torque limitation, and the driving force becomes insufficient due to clutch slippage, but the limp home property by the C grade that can run is secured.

[Fail-safe control action when lubrication solenoid is abnormal]
If the failure that causes the same clutch slip due to the malfunction is extracted, the lubrication SOL malfunction also causes the clutch slip, so the countermeasures were also examined.

That is, in the flowchart of FIG. 6, it is presumed that the oil pressure of the third clutch K3 is normal in S7 and the elements other than the third clutch K3 slip. In this case, control is performed to increase the line pressure PL from S7 to S9, and if the line pressure solenoid 21 is normal, the process proceeds from S9 to S10 → S11 → S13 → S14. In S14, the shift is made to the shift stage of the evacuation destination where the third clutch K3 is used. For example, when the 6th speed is selected, the speed shifts to the 7th speed as the evacuation destination of the third clutch K3.

After shifting to the shift destination of the evacuation destination using the third clutch K3 in S14, if it is determined in the next S15 that there is a gear ratio deviation, the process proceeds from S15 to S17 → S20 → S21 → end. In S20, it is confirmed that the lubrication solenoid 22 is abnormal, and in S21, the process shifts to the shift stage of the evacuation destination where the third clutch K3 is not used.

A time chart showing the fail-safe control action when the lubrication solenoid is abnormal is shown in FIG.

When a failure occurs in the lubrication solenoid 22 at time t1 and the friction coefficient μ of the friction element decreases due to insufficient lubrication flow rate, and slip occurs, the abnormality confirmation (micro slip) timer rises, and a predetermined value is set at time t2. When it reaches, the abnormality is confirmed. When the line pressure PL starts to rise at time t3 after time t2 and the normal / abnormal determination of the line pressure solenoid 21 is completed at time t4, the speed of the automatic transmission 3 is changed to 6th speed from time t4. Shifts to 7th gear. Then, when the abnormality of the lubrication solenoid 22 is confirmed at time t5, the shift stage of the automatic transmission 3 shifts from the 7th speed stage to the 5th speed stage in which the third clutch K3 is not used.

As described above, the abnormality of the lubrication solenoid 22 is that the line pressure solenoid 21 may be abnormal even if the third clutch pressure sensor 24 determines that the third clutch K3 is normal, so the line pressure PL is increased. After that, it is determined whether the hydraulic pressure is operating as intended. Then, when shifting to the shift destination gearbox using the third clutch K3, if there is a shift in the gear ratio at the retractable gearbox and the line pressure PL is moving as intended, the line pressure solenoid 21 is not used. It is determined that the lubrication solenoid 22 is abnormal. When the abnormality of the lubrication solenoid 22 is confirmed, the process shifts to the 5th speed stage in which the third clutch K3 is not used, and the limp home property is ensured by maintaining the runnable state.

As described above, in the control device and the control method of the automatic transmission 3 of the first embodiment, the effects listed below can be obtained.

(1) Control of the automatic transmission 3 that realizes a plurality of gears, the control valve unit 6 that regulates the oil pressure to a plurality of friction elements in the gear train of the automatic transmission 3, and the solenoids of the control valve unit 6. It is provided with a transmission control unit (AT control unit 10) for performing the above. This is the control device for the automatic transmission 3.
The transmission control unit (AT control unit 10) includes a release failure fail-safe control unit 10a corresponding to a release failure when any one of the plurality of friction elements has a release failure.
The release failure fail-safe control unit 10a
When a predetermined gear is selected, the rotation speed detection value of the automatic transmission 3 is monitored, and if the rotation speed detection value deviates from the rotation speed target value of the selected gear, it is selected. It is determined that any of the fastening friction elements fastened at the speed change gear is released abnormally.
At the time of release abnormality determination, the oil pressure detection value of the fastening friction element to be fastened at the selected shift stage is monitored, and if it is determined that the oil pressure detection value is lower than the normal oil pressure, the determined friction element is released. Specify as.
When the release failure friction element is identified, fail-safe control is executed to shift to the evacuation shift stage that does not use the release failure friction element.
Therefore, when a release failure occurs in the friction element of the automatic transmission 3, by promptly identifying the release failure portion, it is possible to quickly evacuate to a speed change stage capable of traveling.
That is, not only the determination is performed only while the vehicle is stopped, but also a measure for identifying the open failure friction element is adopted without executing the "search control" which takes time to identify the failure part. Therefore, when a release failure occurs in the friction element of the automatic transmission 3, the release abnormality is determined in a short time after the failure occurs, and the release failure portion is specified based on the determination of the release abnormality.

(2) The release failure fail-safe control unit 10a
While traveling with a predetermined shift selected, the gear ratio detection value of the automatic transmission 3 is monitored.
If the gear ratio detection value deviates from the gear ratio target value of the selected gear ratio, it is determined that any of the fastening friction elements fastened at the selected gear ratio is a release abnormality.
Therefore, when a release failure occurs in the friction element of the automatic transmission 3 during traveling in which a predetermined shift stage is selected, the release abnormality can be determined in a short time from the occurrence of the failure.
That is, the slip of the friction element due to the release abnormality during traveling can be accurately determined by the deviation between the actual gear ratio and the target gear ratio.

(3) The release failure fail-safe control unit 10a
The difference between the input rotation speed detection value and the input rotation speed target value of the automatic transmission 3 is regulated by restricting the upper limit of the input torque to the automatic transmission 3 when the accelerator is released while the vehicle is stopped with the predetermined shift stage selected. Monitor the number of revolutions.
If the difference rotation speed exceeds a predetermined value and deviates from each other, it is determined that any of the fastening friction elements fastened at the selected shift stage is a release abnormality.
Therefore, when a release failure occurs in the friction element of the automatic transmission 3 while the vehicle is stopped with a predetermined shift stage selected, the release abnormality can be determined in a short time from the occurrence of the failure, and the vehicle is stopped. Torque fluctuation can be suppressed against sudden recovery from failure.
That is, since the slip of the friction element due to the release abnormality while the vehicle is stopped cannot be determined by monitoring the gear ratio, it is determined by the relationship between the actual input rotation speed of the automatic transmission 3 and the target input rotation speed. Then, when the failure while the vehicle is stopped recovers, the vehicle suddenly recovers and torque fluctuation occurs. Therefore, the upper limit of the input torque to the automatic transmission 3 is added to the determination condition when the vehicle is stopped when the accelerator is released. As a result, torque fluctuation can be suppressed even if a sudden recovery from a release failure occurs.

(4) The hydraulic control circuit of the control valve unit 6 has a line pressure solenoid 21 that regulates the line pressure that is the original pressure of the hydraulic pressure for each of the plurality of friction elements.
The release failure fail-safe control unit 10a
When it is determined that the oil pressure detection value is normal at the time of the release abnormality determination, the oil pressure rise command is output to the line pressure solenoid 21.
While searching for the line pressure after outputting the oil pressure rise command, the process shifts to the shift stage of the evacuation destination that uses the friction element determined to have the normal oil pressure detection value.
When the shift speed of the save destination is selected, the rotation speed detection value of the automatic transmission 3 is monitored, and it is determined that the rotation speed detection value deviates from the rotation speed target value of the shift speed of the save destination. Moreover, when it is determined that the line pressure is abnormal by the line pressure search after outputting the oil pressure rise command, the line pressure solenoid 21 is specified as a failure part.
Therefore, when the slip of the fastening friction element is determined, when the cause of the slip is a line pressure failure, the line pressure solenoid 21 is specified as a failure site, and the slip of the fastening friction element is prevented from occurring again. be able to.
That is, even if the flood control is normal, if there is a line pressure failure, the friction element may slip again at the shift stage of the evacuation destination. On the other hand, by instructing the increase of the line pressure PL after estimating the failure site, it is possible to determine whether or not the line pressure has failed to the friction element.

(5) When the line pressure solenoid 21 is identified as a failure portion, the release failure fail-safe control unit 10a executes fail-safe control that limits the upper limit of the input torque to the automatic transmission 3.
Therefore, when the line pressure solenoid 21 is the faulty part, it is possible to prevent the line pressure solenoid 21 from moving to the gear shifting stage where the vehicle can travel quickly due to the clutch burning after shifting to the limp home. That is, by limiting the upper limit of the input torque to the automatic transmission 3, the amount of heat generated by the friction element slipping due to insufficient line pressure after shifting to the limp home can be suppressed.

(6) The hydraulic control circuit of the control valve unit 6 includes a lubrication solenoid 22 that regulates the lubrication flow rate supplied to the friction element to an appropriate flow rate that suppresses heat generation.
The release failure fail-safe control unit 10a
When the shift speed of the save destination is selected, the rotation speed detection value of the automatic transmission 3 is monitored, and it is determined that the rotation speed detection value deviates from the rotation speed target value of the shift speed of the save destination. Moreover, when it is determined that the line pressure is normal by the line pressure search after outputting the oil pressure rise command, the lubrication solenoid 22 is specified as a failure part.
Therefore, when the slip of the fastening friction element is determined, the lubrication solenoid 22 is specified as a failure site when the cause of the slip is μ deterioration due to insufficient lubrication flow rate, and the fastening friction element slips again. Can be prevented.
That is, even if the oil pressure is normal, if there is μ deterioration due to insufficient lubrication flow rate, the friction element may slip again at the shift stage of the evacuation destination. On the other hand, by instructing to raise the line pressure PL after estimating the failure site, it is possible to determine whether or not there is a line pressure failure to the friction element, and if the line pressure is normal, the lubrication solenoid 22 is operated. It can be identified as a faulty part.

(7) The release failure fail-safe control unit 10a performs fail-safe control that shifts to the evacuation shift stage that does not use the friction element determined that the oil pressure detection value is normal when the lubrication solenoid 22 is identified as the failure site. Execute.
Therefore, when the lubrication solenoid 22 is the faulty part, it is possible to prevent the lubrication solenoid 22 from moving to the gear shifting stage where the vehicle can travel quickly due to the burning of the clutch after shifting to the limp home.
That is, after shifting to the evacuation shift stage that does not use the friction element determined to have a normal oil pressure detection value and changing the fastening friction element, after shifting to the limp home, even if there is insufficient lubrication flow rate, the initial stage The friction element temperature can be kept low.

(8) Control of the automatic transmission 3 that realizes a plurality of gears, the control valve unit 6 that regulates the oil pressure to a plurality of friction elements in the gear train of the automatic transmission 3, and the solenoids of the control valve unit 6. It is provided with a transmission control unit (AT control unit 10) for performing the above. In the control method of the automatic transmission 3, the transmission control unit (AT control unit 10) corresponds to a release failure when any one of the plurality of friction elements has a release failure.
When a predetermined gear is selected, the rotation speed detection value of the automatic transmission 3 is monitored, and if the rotation speed detection value deviates from the rotation speed target value of the selected gear, it is selected. It is determined that any of the fastening friction elements fastened at the speed change gear is released abnormally.
At the time of release abnormality determination, the oil pressure detection value of the fastening friction element to be fastened at the selected shift stage is monitored, and if it is determined that the oil pressure detection value is lower than the normal oil pressure, the determined friction element is released. Specify as.
When the release failure friction element is identified, fail-safe control is executed to shift to the evacuation shift stage that does not use the release failure friction element.
Therefore, when a release failure occurs in the friction element of the automatic transmission 3, by promptly identifying the release failure portion, it is possible to quickly evacuate to a speed change stage capable of traveling.
That is, not only the determination is performed only while the vehicle is stopped, but also a measure for identifying the open failure friction element is adopted without executing the "search control" which takes time to identify the failure part. Therefore, when a release failure occurs in the friction element of the automatic transmission 3, the release abnormality is determined in a short time after the failure occurs, and the release failure portion is specified based on the determination of the release abnormality.

The control device and control method for the automatic transmission of the present invention have been described above based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and design changes and additions are permitted as long as the gist of the invention according to each claim is not deviated from the claims.

In the first embodiment, attention is paid to the third clutch K3 among the plurality of friction elements B1, B2, B3, K1, K2, K3, and an example in which the third clutch pressure sensor 24 and the line pressure sensor 25 are provided as the oil pressure sensor is shown. It was. However, as the oil pressure sensor, an example may be provided in which the oil pressure sensors of the friction elements B1, B2, B3, K1 and K2 are provided, respectively, or an example in which a selected oil pressure sensor is provided as needed.

In the first embodiment, as an automatic transmission, an example of an automatic transmission 3 having 9 forward speeds and 1 reverse speed is shown. However, the automatic transmission may be an example of an automatic transmission having a stepped speed change other than the forward 9th speed and the backward 1st speed. Further, in the first embodiment, an example of a control device and a control method of an automatic transmission mounted on an engine vehicle is shown, but the control device and control of an automatic transmission such as a hybrid vehicle or an electric vehicle are not limited to the engine vehicle. It can also be applied as a method.

Claims (8)

An automatic transmission that realizes a plurality of gears, a control valve unit that regulates oil pressure to a plurality of friction elements in the gear train of the automatic transmission, and a transmission control that controls each solenoid of the control valve unit. A control device for an automatic transmission equipped with a unit.
The transmission control unit has a release failure fail-safe control unit corresponding to a release failure when any one of the plurality of friction elements has a release failure.
The release failure fail-safe control unit
When a predetermined gear is selected, the rotation speed detection value of the automatic transmission is monitored, and if the rotation speed detection value deviates from the rotation speed target value of the selected gear, it is selected. It is determined that any of the fastening friction elements fastened at the speed change gears is released abnormally, and
At the time of release abnormality determination, the oil pressure detection value of the fastening friction element to be fastened at the selected shift stage is monitored, and if it is determined that the oil pressure detection value is lower than the normal oil pressure, the determined friction element is released. Identify as an element
When the release failure friction element is specified, a fail-safe control for shifting to an evacuation shift stage that does not use the release failure friction element is executed.
Control device for automatic transmission. In the control device for the automatic transmission according to claim 1,
The release failure fail-safe control unit
While traveling with a predetermined shift selected, the gear ratio detection value of the automatic transmission is monitored, and
If the gear ratio detection value deviates from the gear ratio target value of the selected gear ratio, it is determined that any of the fastening friction elements fastened at the selected gear ratio is a release abnormality.
Control device for automatic transmission. In the control device for the automatic transmission according to claim 1 or 2.
The release failure fail-safe control unit
While the vehicle is stopped with a predetermined gear selected, the upper limit of the input torque to the automatic transmission is regulated when the accelerator is released, and the difference between the input rotation speed detection value and the input rotation speed target value of the automatic transmission. Monitor the number of revolutions and
If the difference rotation speed exceeds a predetermined value and deviates, it is determined that any of the fastening friction elements fastened at the selected shift stage is a release abnormality.
Control device for automatic transmission. In the control device for the automatic transmission according to any one of claims 1 to 3.
The hydraulic control circuit of the control valve unit has a line pressure solenoid that regulates the line pressure that is the original pressure of the hydraulic pressure to each of the plurality of friction elements.
The release failure fail-safe control unit
When it is determined that the oil pressure detection value is normal at the time of the release abnormality determination, the oil pressure rise command is output to the line pressure solenoid.
While searching for the line pressure after outputting the oil pressure increase command, the process shifts to the shift stage of the evacuation destination using the friction element determined to be normal in the oil pressure detection value.
When the shift stage of the save destination is selected, the rotation speed detection value of the automatic transmission is monitored, and the rotation speed detection value deviates from the rotation speed target value of the shift stage of the save destination. If it is determined and the line pressure is determined to be abnormal by the line pressure search after outputting the oil pressure increase command, the line pressure solenoid is identified as a failure site.
Control device for automatic transmission. In the control device for the automatic transmission according to claim 4,
When the line pressure solenoid is identified as a failure portion, the release failure fail-safe control unit executes fail-safe control that limits the upper limit of the input torque to the automatic transmission.
Control device for automatic transmission. In the control device for the automatic transmission according to claim 4 or 5.
The hydraulic control circuit of the control valve unit has a lubrication solenoid that regulates the lubrication flow rate supplied to the friction element to an appropriate flow rate that suppresses heat generation.
The release failure fail-safe control unit
When the shift stage of the save destination is selected, the rotation speed detection value of the automatic transmission is monitored, and the rotation speed detection value deviates from the rotation speed target value of the shift stage of the save destination. If it is determined and the line pressure is determined to be normal by the line pressure search after outputting the oil pressure increase command, the lubrication solenoid is specified as a failure site.
Control device for automatic transmission. In the control device for the automatic transmission according to claim 6,
When the lubrication solenoid is identified as a failure site, the release failure fail-safe control unit executes a fail-safe control that shifts to an evacuation shift stage that does not use the friction element determined to have a normal oil pressure detection value. ,
Control device for automatic transmission. An automatic transmission that realizes a plurality of gears, a control valve unit that regulates oil pressure to a plurality of friction elements in the gear train of the automatic transmission, and a transmission control that controls each solenoid of the control valve unit. A control method for an automatic transmission including a unit, wherein the transmission control unit corresponds to a release failure when any one of the plurality of friction elements has a release failure, and is predetermined. When the shift stage is selected, the rotation speed detection value of the automatic transmission is monitored, and if the rotation speed detection value deviates from the rotation speed target value of the selected transmission speed, it is selected. It is determined that any of the fastening friction elements fastened at the current shift stage has a release abnormality, and at the time of the release abnormality judgment, the oil pressure detection value of the fastening friction element fastened at the selected shift stage is monitored, and the oil pressure detection value When it is determined that is lower than the normal oil pressure, the determined friction element is specified as the release failure friction element, and when the release failure friction element is specified, the shift to the retract shift stage which does not use the release failure friction element is performed. An automatic transmission control method that performs fail-safe control.

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