WO2020031678A1

WO2020031678A1 - Control device for automatic transmission

Info

Publication number: WO2020031678A1
Application number: PCT/JP2019/028736
Authority: WO
Inventors: 濱野　正宏; 邦彦奥村
Original assignee: ジヤトコ株式会社; 日産自動車株式会社
Priority date: 2018-08-07
Filing date: 2019-07-23
Publication date: 2020-02-13
Also published as: JPWO2020031678A1; JP6913255B2

Abstract

This control device for automatic transmission (3) comprises an AT control unit (10) having a solenoid fault diagnosis unit (10a), a drive force calculation unit (10b) and a failsafe control unit (10c). If the current differential obtained by subtracting the actual current from the command current to a clutch solenoid (20) is equal to or greater than a predetermined current, the solenoid fault diagnosis unit (10a) diagnoses a fault mode. If the fault mode is diagnosed, the drive force calculation unit (10b) calculates a first drive force (A) obtained when an input torque limit is assumed, and a second drive force (B) obtained when a transmission restriction is assumed. If the first drive force (A) is equal to or greater than the second drive force (B), the failsafe control unit (10c) selects an input torque limit, and if the first drive force (A) is less than the second drive force (B), selects transmission restriction.

Description

Control device for automatic transmission

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

Conventionally, there has been known a hydraulic control device for a continuously variable transmission that prevents a belt slip at the time of an abnormality and enables the vehicle to travel at a minimum (see Patent Document 1). In this hydraulic control system, a solenoid valve generates a duty pressure in which the reducing pressure is corrected by an electric signal using a constant reducing pressure as a base pressure, and the duty pressure acts on a line pressure control valve to control the line pressure. A hydraulic clutch is provided in the oil path of the above-mentioned reducing pressure to detect an abnormality in the line pressure control. Restrict.

However, in the above-described conventional device, when an abnormality in the line pressure control is detected, the clutch torque is limited by the minimum line pressure. For this reason, the torque transmitted to the drive wheels is limited to the torque determined by the minimum line pressure, and there is a problem that the driving force is insufficient and the driver may feel uncomfortable.

JP-A-62-52260

The present invention has been made in view of the above problem, and when the clutch solenoid of the automatic transmission fails, it is possible to prevent the driving performance from becoming insufficient during limp home traveling while preventing the traveling performance from deteriorating due to future component damage. The purpose is to prevent it.

In order to achieve the above object, a control device for an automatic transmission according to the present invention includes an automatic transmission, a control valve unit, and a transmission control unit.
The hydraulic control circuit of the control valve unit has a clutch solenoid for individually adjusting the hydraulic pressure supplied to the friction element.
The transmission control unit includes a solenoid failure diagnosis unit for the clutch solenoid, a driving force calculation unit that calculates the driving force in the solenoid failure mode, and a fail-safe control unit that takes measures against the solenoid failure mode.
The solenoid failure diagnosis unit diagnoses a failure mode when a current difference obtained by subtracting an actual current from a command current to the clutch solenoid is equal to or greater than a predetermined current.
When the failure mode is diagnosed, the driving force calculation unit determines the first driving force obtained when the input torque to the automatic transmission is limited, and shifts to a shift speed that does not use the abnormally diagnosed abnormal clutch solenoid. And the second driving force obtained when is assumed.
The fail-safe control unit selects the input torque restriction when the first driving force is equal to or more than the second driving force, and selects the shift restriction when the first driving force is less than the second driving force.

As described above, when the actual current to the clutch solenoid is reduced due to a failure, the first driving force when the input torque limit is selected is compared with the second driving force when the shift limit is selected, and the driving force is higher. The method of selecting the fail-safe control is adopted. As a result, when the clutch solenoid of the automatic transmission breaks down, it is possible to prevent the running performance from deteriorating due to future component damage and prevent the driving force from becoming insufficient during limp home running.

1 is an overall system diagram illustrating an engine vehicle equipped with an automatic transmission to which a control device according to a first embodiment is applied. FIG. 2 is a skeleton diagram illustrating an example of an automatic transmission to which the control device according to the first embodiment is applied. FIG. 3 is an engagement table illustrating engagement states of shift friction elements at each shift speed in the automatic transmission to which the control device of the first embodiment is applied. FIG. 3 is a shift map diagram illustrating an example of a shift map in the automatic transmission to which the control device of the first embodiment is applied. FIG. 2 is a control system configuration diagram illustrating a detailed configuration of a control valve unit and an AT control unit according to the first embodiment. 5 is a flowchart illustrating a flow of a fail-safe control process at the time of clutch solenoid failure diagnosis executed by a solenoid failure diagnosis unit, a driving force calculation unit, and a fail-safe control unit of the AT control unit according to the first embodiment. FIG. 8 is an explanatory diagram of the influence of the occurrence of erroneous release showing the magnitude of the clutch pressure and the possibility of occurrence of erroneous release during clutch engagement by the maximum command pressure. FIG. 9 is a characteristic diagram showing a relationship between an SOL command current and a SOL monitor current, which indicates a failure mode in clutch solenoid failure diagnosis during clutch engagement with a maximum command pressure. FIG. 6 is an input torque-acceleration characteristic diagram showing a comparison between the first acceleration and the second acceleration when a failure diagnosis is performed on the second clutch solenoid that engages the second clutch during the selection of the second speed in the first embodiment. FIG. 7 is an input torque-acceleration characteristic diagram showing a comparison between the first acceleration and the second acceleration when a failure diagnosis is performed on the second clutch solenoid that engages the second clutch during the selection of the third speed in the first embodiment. FIG. 7 is an input torque-acceleration characteristic diagram showing a comparison between the first acceleration and the second acceleration when a failure diagnosis is performed on the second clutch solenoid that engages the second clutch during selection of the fifth speed in the first embodiment. 6 is a time chart showing characteristics explaining a fail-safe control operation at the time of running failure diagnosis (other than contamination) of the third brake solenoid for engaging the third brake at the fifth speed in the first embodiment.

Hereinafter, an embodiment of a control device for an automatic transmission according to the present invention will be described based on a first embodiment shown in the drawings.

The control device according to the first embodiment is applied to an engine vehicle (an example of a vehicle) equipped with an automatic transmission having nine forward speeds and one reverse speed. Hereinafter, the configuration of the first embodiment is divided into “entire system configuration”, “detailed configuration of the automatic transmission”, “detailed configuration of the hydraulic / electronic control system”, and “fail-safe control processing configuration at the time of clutch solenoid failure diagnosis”. 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 of the first embodiment is applied. Hereinafter, the overall system configuration will be described with reference to 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, as shown in FIG. The automatic transmission 3 is provided with a control valve unit 6 including a spool valve for shifting, a hydraulic control circuit, a solenoid valve, and the like. The actuators (the clutch solenoid 20, the line pressure solenoid 21, the lubrication solenoid 22, and the lock-up 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 lock-up clutch 2a that directly connects the crankshaft of the engine 1 and the input shaft IN of the automatic transmission 3 by fastening.

(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, as shown in FIG. The AT control unit 10 includes a solenoid failure diagnosis unit 10a, a driving force calculation unit 10b, and a fail-safe control unit 10c.

The AT control unit 10 which is a control device of the automatic transmission 3 inputs signals from 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, and the like.

The turbine rotation sensor 13 detects the turbine speed of the torque converter 2 (= transmission input shaft speed) and sends a signal of the turbine 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. ATF oil temperature sensor 15 detects the temperature of ATF (oil for automatic transmission) and sends a signal of ATF oil temperature TATF to AT control unit 10. The inhibitor switch 18 detects a range position selected by a driver's selection operation on a select lever, a 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 (the intermediate shaft = the rotation 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 AT control unit 10 monitors changes in the operating point (VSP, APO) due to the vehicle speed VSP and the accelerator opening APO on the shift map (see FIG. 4),
1. Auto upshift (by increasing vehicle speed while maintaining accelerator opening)
2. Release the upshift (by releasing the accelerator)
3. Foot return upshift (by returning the accelerator)
4. Power-on downshift (due to decrease in vehicle speed while maintaining accelerator opening)
5.Small opening sudden downshift (depending on small accelerator operation amount)
6. Large opening rapid downshift (depending on accelerator operation amount: "Kick down")
7. Slow downshift (by slow accelerator operation and increasing vehicle speed)
8. Coast downshift (by lowering the vehicle speed by releasing the accelerator pedal)
The shift control is performed according to a basic shift pattern called a basic shift pattern.

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

The engine control unit 11 performs engine torque limiting control and the like by cooperative control with the control by the AT control unit 10 in addition to various controls of the engine alone. The AT control unit 10 and the engine control unit 11 are connected via a CAN communication line 12 capable of bidirectional information exchange. Therefore, when an information request is input from the AT control unit 10, the engine control unit 11 sends information of the accelerator opening APO, the engine speed Ne, the engine torque Te, and the turbine torque Tt to the AT control unit 10 in response to the request. Output. When an engine torque restriction request based on the upper limit torque is input from the AT control unit 10, engine torque restriction control is performed to limit the engine torque to a torque restricted by the 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 of the first embodiment is applied, FIG. 3 is a fastening table for the automatic transmission 3, and FIG. 4 shows an example of a map. Hereinafter, a detailed configuration of the automatic transmission 3 will be described with reference to FIGS.

The automatic transmission 3 has the following features.
(a) A one-way clutch that mechanically engages and idles is not used as a transmission 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 during gear shifting. Is controlled.
(b) The second clutch K2 and the third clutch K3 have a centrifugal cancel chamber for canceling a centrifugal pressure caused by a centrifugal force acting on the clutch piston oil chamber.

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

The first planetary gear PG1 is a single pinion type planetary gear, and includes 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 includes 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 includes 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 includes 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.

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 shown in FIG. A first brake B1, a second brake B2, a third brake B3, a first clutch K1, a second clutch K2, and a third clutch K3 are provided as friction elements to be engaged / released by the shift. I have.

The input shaft IN is a shaft to which the driving force from the engine 1 is inputted 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 that the input shaft IN can be connected and disconnected.

The output shaft OUT is a shaft that outputs a drive torque shifted to the drive wheels 5 via the propeller shaft 4 and a 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 able to connect and disconnect.

The first connection 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 constantly 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. Member.

The first brake B1 is a friction element capable of locking the rotation of the first carrier C1 to the transmission case TC. The second brake B2 is a friction element capable of locking the rotation of the third ring gear R3 to the transmission case TC. The third brake B3 is a friction element capable of locking the rotation of the second sun gear S2 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 the first carrier C1 and the second connection member M2.

FIG. 3 shows an engagement table that achieves nine forward speeds and one reverse speed in the D range by combining three simultaneous engagements of the six friction elements in the automatic transmission 3. Hereinafter, a shift configuration for establishing each shift speed 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 fourth 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-mentioned first to fifth speed stages are underdrive speed stages based on the reduction gear ratio whose gear ratio exceeds 1.

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

The seventh speed (7th) is achieved by simultaneously engaging the third brake B3, the first clutch K1, and the third clutch K3. The eighth speed (8th) is achieved by simultaneously engaging the first brake B1, the first clutch K1, and the third clutch K3. The ninth speed (9th) is achieved by simultaneously engaging the first brake B1, the third brake B3, and the first clutch K1. The above-mentioned seventh to ninth speed stages are overdrive speed stages with a speed increasing gear ratio having a gear ratio of less than one.

Further, when performing an upshift or an downshift to an adjacent speed, from among the first to ninth speeds, as shown in FIG. . That is, the shift to the adjacent shift speed is achieved by releasing one friction element and engaging one friction element while maintaining the engagement of two of the three friction elements. .

後 The reverse speed (Rev) by selecting the R range position is achieved by simultaneously applying 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, 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 speed from the first gear to the ninth gear on the forward side by selecting the D range is performed. This is performed 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 request is issued. When the operating point (VSP, APO) crosses the downshift line shown by the broken line in FIG. 4, a downshift 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 according to 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 pressure sources. The mechanical oil pump 61 is driven by the engine 1, and the electric oil pump 62 is driven by an 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 lock-up solenoid 23 as valves provided in the hydraulic 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 regulating valve 64 regulates the discharge 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 operation signal pressure from the line pressure solenoid 21.

The clutch solenoid 20 uses the line pressure PL as the original pressure, and individually controls the engagement pressure, the release pressure, and the like for each of the friction elements B1, B2, B3, K1, K2, and K3. In FIG. 5, it is illustrated that one clutch solenoid 20 is provided. However, there are six solenoids (first brake solenoid, second brake solenoid, third brake solenoid, first clutch solenoid, second clutch solenoid, third clutch Solenoid).

The lock-up solenoid 23 controls the differential pressure of the lock-up clutch 2a using excess oil when the line pressure PL is regulated by the line pressure regulating valve 64.

The lubrication solenoid 22 generates a valve operation 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 lubricating pressure regulating valve 65 can control the lubricating flow 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 lubricating solenoid 22. Then, friction is reduced by optimizing the PT supply lubrication flow rate by the lubrication pressure regulating valve 65.

(4) The boost switching valve 66 increases the amount of oil supplied to the centrifugal cancel chamber 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 supply oil amount is temporarily increased in a scene where the oil amount in the centrifugal cancel chamber is insufficient.

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

As described above, the control valve unit 6 is characterized in that the shift-by-wire structure is adopted and the manual valve for switching between the D range pressure oil passage and the R range pressure oil passage is eliminated. Further, specific valve elements such as the lubricating solenoid 22, the lubricating pressure regulating valve 65, the boost switching valve 66, and the P-nP switching valve 67 are provided.

As shown in FIG. 5, the AT control unit 10 includes a solenoid failure diagnosis unit 10a for diagnosing a solenoid failure of the clutch solenoid 20, a driving force calculation unit 10b for calculating a driving force in the solenoid failure mode, and a solenoid failure mode. And a fail-safe control unit 10c for taking measures against the above. Here, the solenoid failure diagnosing unit 10a outputs the SOL monitor current (hereinafter, referred to as “actual current”) from the solenoid drive circuit 69 and the SOL instruction current (hereinafter, “instruction current”) output from the AT control unit 10. )). The solenoid drive circuit 69 corrects the current by the current feedback control so that the actual current follows the instruction current.

The solenoid failure diagnosis unit 10a diagnoses the failure diagnosis target clutch solenoid 20 as a failure mode when the state in which the current difference obtained by subtracting the actual current from the instruction current to the clutch solenoid 20 is equal to or greater than a predetermined current continues for a predetermined time or more. .

When the failure mode is diagnosed, the driving force calculation unit 10b calculates a first driving force A that is obtained when the input torque to the automatic transmission 3 is limited and a gear position that does not use the abnormally diagnosed abnormal clutch solenoid. And the second driving force B obtained when assuming the transition to.

The driving force calculation unit 10b calculates the clutch capacity of the friction element that is hydraulically engaged by the actual current to the abnormal clutch solenoid, and calculates the input torque regulation value to the automatic transmission 3 according to the calculated clutch capacity. Then, the first driving force A is obtained by a driving force calculation assuming full-open acceleration with the input torque regulation value. The “driving force assuming full-open acceleration with the input torque regulation value” refers to the upper limit torque (= input torque) such that the input torque of the automatic transmission 3 becomes the input torque regulation value even when the full-open acceleration is performed. In other words, it can be rephrased as a driving force when a torque regulation value is assumed.

The driving force calculation unit 10b calculates a shift pattern at a shift speed that does not use the abnormal clutch solenoid. Then, when there are a plurality of shift speeds that do not use the abnormal clutch solenoid, the lowest shift speed is selected by shifting limitation. Then, the second driving force B is obtained by a driving force calculation assuming an upper limit input torque at which clutch slip does not occur at the selected gear position.

The fail-safe control unit 10c selects the input torque limit when the first driving force A is equal to or greater than the second driving force B, and selects the shift limit when the first driving force A is less than the second driving force B.

When the input torque limitation is selected when the first driving force A is equal to or higher than the second driving force B, the fail-safe control unit 10c receives the signal from the engine 1 (driving drive source) while keeping the automatic transmission 3 at the same speed. An input torque regulation request for limiting the maximum value of the input torque to the input torque regulation value is output.

When the first drive force A is less than the second drive force B and the shift restriction is selected, the fail-safe control unit 10c forcibly turns off the abnormal clutch solenoid and changes the gear position of the automatic transmission 3 to the second drive force B. Is switched to the calculated gear.

[Fail-safe control processing configuration at clutch solenoid failure diagnosis]
FIG. 6 shows a flow of the fail-safe control process at the time of clutch solenoid failure diagnosis executed by the solenoid failure diagnosis unit 10a, the driving force calculation unit 10b, and the fail-safe control unit 10c of the AT control unit 10 according to the first embodiment. Hereinafter, each step of FIG. 6 will be described. Note that the fail-safe control process is executed for the clutch solenoid 20 that regulates the oil pressure to the engaged friction element while the vehicle is stopped and the vehicle is traveling while the predetermined gear position is selected.

In step S1, following the start or determination of NO in S4 or S9, it is determined whether or not (instruction current−actual current) of clutch solenoid 20 (= shift SOL) ≧ predetermined current. If YES ｛(instruction current−actual current) ≧ predetermined current｝, proceed to step S2. If NO ｛(instruction current−actual current) <predetermined current｝, proceed to step S14.

Here, the “predetermined current” is a current value set in advance as a current deviation determination threshold value for determining that the clutch solenoid 20 is out of order. The "instruction current" is an instruction current for obtaining the MAX pressure when the friction element is engaged.

In step S2, following the determination in step S1 that (instruction current−actual current) ≧ predetermined current, the timer is counted, and the flow proceeds to step S3.

In step S3, following the timer count in S2, it is determined whether or not a timer indicating a continuation time in which (instruction current−actual current) ≧ predetermined current is equal to or longer than a predetermined time. If YES (timer ≧ predetermined time), the process proceeds to step S4, and if NO (timer <predetermined time), the process returns to step S1.

Here, the predetermined time is set such that (indicated current−actual current) ≧ predetermined current is instantaneously established, thereby preventing the erroneous diagnosis that the clutch solenoid 20 has failed, and the clutch solenoid 20 performs the failure diagnosis with high accuracy. Set to a time when you can.

In step S4, following the determination in step S3 that the timer is greater than or equal to the predetermined time, the abnormality of the clutch solenoid 20 diagnosed as being in the failure mode is determined, and the process proceeds to step S5.

In step S5, following the determination of the abnormality in S4, the clutch capacity of the friction element engaged by the abnormal clutch solenoid is calculated from the actual current to the clutch solenoid 20 in which the abnormality has been determined, and the process proceeds to step S6.

Here, when the actual current to the clutch solenoid 20 in which the abnormality is determined is detected, the engagement hydraulic pressure supplied to the friction element is known from the relationship between the actual current and the hydraulic pressure, and the friction is determined by the engagement hydraulic pressure, the pressure receiving area, the number of clutches, and the like. The clutch capacity of the element can be determined.

In step S6, following the calculation of the clutch capacity in S5, an input torque regulation value corresponding to the calculated clutch capacity is calculated, and the process proceeds to step S7.

Here, the input torque regulation value is calculated by subtracting an error or the like from the calculated clutch capacity because the friction element slips when the input torque exceeds the clutch capacity.

In step S7, following the calculation of the input torque regulation value, the first driving force A is calculated based on the input torque regulation value, and the process proceeds to step S8.

Here, the first driving force A is a starting driving force in the failure mode of the clutch solenoid 20, and is obtained by a driving force calculation assuming full-open acceleration with the input torque regulation value.

In step S8, following the calculation of the first driving force A in S7, a shift restriction pattern at a shift speed not using the abnormally diagnosed abnormal clutch solenoid is calculated, and the routine proceeds to step S9.

Here, when there are a plurality of shift speeds that do not use the abnormal clutch solenoid, the lowest shift speed is selected based on the shift limit.

In step S9, following the calculation of the shift restriction pattern in S8, the second driving force B due to the shift restriction in the shift speed not using the abnormal clutch solenoid is calculated, and the routine proceeds to step S10.

Here, the second driving force B is a starting driving force in the failure mode of the clutch solenoid 20, and is calculated by a driving force calculation assuming an upper limit input torque at which clutch slip does not occur at the selected shift speed.

In step S10, following the calculation of the second driving force B in S9, the first driving force A and the second driving force B are compared and determined. If the comparison result is A ≧ B, the process proceeds to step S11. If the comparison result is A <B, the process proceeds to step S12.

In step S11, following the determination in S10 that A ≧ B, a request to regulate the input torque according to the calculated clutch capacity is output to the engine control unit 11, and the routine proceeds to the end.

In step S12, following the determination of A <B in S10, the abnormal clutch solenoid is forcibly turned off, an instruction current (= 0 mA) is output, and the process proceeds to step S13.

In step S13, following the forced OFF of the abnormal clutch solenoid in S12, a shift restriction for selecting a gear position in which the abnormal clutch solenoid is not used is performed, and the process proceeds to the end.

In step S14, following the determination in step S1 that (instruction current-actual current) <predetermined current, the timer that has been counted up to that point is reset, and the process proceeds to the end.

Next, the operation of the first embodiment will be described by dividing it into "background technology", "fail-safe control operation at the time of clutch solenoid failure diagnosis", "fail-safe control operation during stop", and "fail-safe control operation during running". I do.

[Background Art]
In the automatic transmission unit to which the present invention is applied, each of the friction elements involved in the shift is shifted by a clutch solenoid, and it is necessary to consider a failure response. Diagnosis of malfunctions of clutch solenoids was also performed for existing automatic transmission units, but there are new issues due to functional safety requirements and system differences.

Therefore, when the command current to the clutch solenoid deviates from the actual current, the solenoid failure diagnosis and the failure to select the larger one of the driving force assuming the input torque limitation and the driving force assuming the gear shifting limitation are performed. We decided to incorporate safe processing. The following describes (1) {system outline, (2) analysis of the influence of intermediate deviation on command current, and (3) {clarification of issues.

(1) System overview (difference from existing units)
The automatic transmission unit to which the present invention is applied employs shift-by-wire and eliminates the manual valve. On the other hand, the existing automatic transmission unit provided a manual valve to assure forward / reverse movement, but there is a new failure mode due to the lack of that function.

(2) Analysis of the effect of intermediate deviation on the command currentIf the actual current is intermediate deviation toward the HIGH side with respect to the instruction current to the clutch solenoid, if the clutch pressure becomes higher than the clutch pressure during clutch disengagement Erroneous fastening occurs. Therefore, there is a risk that sudden deceleration may occur due to simultaneous engagement of a plurality of elements, and it is necessary to take measures such as immediately shifting to the gear position of the evacuation destination based on the failure diagnosis.

On the other hand, when the actual current has an intermediate deviation toward the LOW side with respect to the command current to the clutch solenoid, unlike the case where the actual current has an intermediate deviation toward the HIGH side, as shown in FIG. The effect changes depending on the situation.
That is, during clutch engagement according to the MAX pressure instruction, erroneous release does not occur as long as the clutch pressure is equal to or higher than the actual pressure corresponding to the safety factor of 1.0, as shown in FIG. However, erroneous release occurs from the time when the clutch pressure becomes less than the actual pressure corresponding to the safety factor of 1.0 to the time when the clutch cannot be brought into contact (the vehicle can run, but the driving force is insufficient due to clutch slip). Further, when the clutch pressure becomes less than the pressure at which the clutch cannot be brought into contact, complete erroneous release occurs (running is impossible).

(3) Clarification of the problem The following was clarified from the analysis of the influence of the intermediate deviation on the indicated current. If the actual current deviates to the LOW side with respect to the command current (MAX) to the clutch solenoid during clutch engagement, clutch slippage will occur if the safety factor is less than 1.0. Does not occur. Therefore, from the result of the influence analysis, the failure mode in which the current difference obtained by subtracting the actual current from the command current to the clutch solenoid 20 is equal to or greater than the predetermined current is switched to two failure modes depending on whether the actual current is equal to or less than the clutch slip threshold. Can be divided.

That is, as shown in FIG. 8, when the actual current is less than the clutch slip threshold and the failure mode is lower than the safety factor 1.0, in order to prevent the running performance from deteriorating at the time of failure, the shift restriction without using the abnormal clutch solenoid is performed. "Limited failure mode". However, when the actual current is equal to or higher than the clutch slip threshold and the failure mode is a safety factor of 1.0 or higher, deterioration of traveling performance due to future component damage due to clutch slip is prevented. It becomes the "selection failure mode" in which it is possible to select either.

課題 When the problem is extracted from the above analysis result, when the actual current is in the “selection failure mode” region equal to or higher than the clutch slip threshold, the degree of freedom of the fail-safe control can be utilized. In view of the above, an object of the present invention is to secure the limp home property by selecting one of the input torque limit and the gear shift limit so that the driving force does not become insufficient in the limp home traveling.

[Fail-safe control at clutch solenoid failure diagnosis]
The present invention has been made by focusing on the problem extracted in the above (3) Problem clarification. As means for solving the problem, the AT control unit 10 includes a solenoid failure diagnosis unit 10a for the clutch solenoid 20, a driving force calculation unit 10b for calculating the driving force in the solenoid failure mode, and fail-safe control for taking measures against the solenoid failure mode. A portion 10c. The solenoid failure diagnosis unit 10a diagnoses a failure mode when a current difference obtained by subtracting an actual current from a command current to the clutch solenoid 20 is equal to or larger than a predetermined current. When the failure mode is diagnosed, the driving force calculation unit 10b calculates a first driving force A that is obtained when the input torque to the automatic transmission 3 is limited and a gear position that does not use the abnormally diagnosed abnormal clutch solenoid. And the second driving force B obtained when assuming the transition to. The fail-safe control unit 10c selects the input torque limit when the first driving force A is equal to or more than the second driving force B, and selects the gear shift restriction when the first driving force A is less than the second driving force B. It was adopted.

That is, when the predetermined time has elapsed while the condition of (instruction current−actual current) ≧ predetermined current is satisfied, in the flowchart of FIG. 6, S1 → S2 → S3 → S4 → S5 → S6 → S7 → S8 → S9. move on. In S7, assuming that the input torque is limited, the first driving force A is calculated based on the input torque regulation value. In S9, the second driving force B is calculated based on the gear position where the abnormal clutch solenoid is not used, assuming that the gear change is to be restricted.

In the next S10, the first driving force A and the second driving force B are compared and determined. If the result of the comparison is A ≧ B, the process proceeds to S11, where a request to regulate the input torque according to the calculated clutch capacity is output to the engine control unit 11.

On the other hand, if the result of the comparison determination in S10 is A <B, the process proceeds to S12 → S13. In S12, the abnormal clutch solenoid is forcibly turned off. In S13, the shift restriction for selecting a gear position that does not use the abnormal clutch solenoid. Is performed.

As a result, when the clutch solenoid 20 of the automatic transmission 3 breaks down, it is possible to prevent the running performance from being degraded due to the damage of parts in the future and to prevent the driving force from becoming insufficient during limp home running.

That is, when the actual current to the clutch solenoid 20 is reduced due to a failure, the first driving force A when the input torque limit is selected is compared with the second driving force B when the shift limit is selected. The higher failsafe control is selected. In this way, by selecting either the input torque limit or the disguise limit based on the technical idea of giving priority to the driving force, it is possible to prevent the driving force from becoming insufficient during limp home traveling after the failure diagnosis of the clutch solenoid 20. Is done.

Hereinafter, a comparison judgment between the first driving force A and the second driving force B will be described based on specific examples shown in FIGS.

When the failure of the second clutch solenoid that engages the second clutch K2 is determined during the selection of the second speed, when the input torque is limited while the speed is fixed to the second speed, and when the speed is changed from the second speed to the first speed. FIG. 9 shows the input torque-acceleration characteristics when the shift to the speed stage is limited.

When the input torque is limited while the gear position is fixed at the second speed, the acceleration G assuming full-open acceleration with the input torque restriction value is the first acceleration G1 (2nd). On the other hand, when the shift stage is shifted from the second shift stage to the first shift stage selected by the shift limit, and the upper limit input torque at which there is no clutch slip at the first shift stage, the acceleration G becomes the second acceleration G2 (1st). Become. Therefore, comparing the first acceleration G1 (2nd) with the second acceleration G2 (1st), the first acceleration G1 (2nd)> the second acceleration G2 (1st). Since the acceleration G can be replaced by the magnitude of the driving force of the vehicle, the first acceleration G1 (2nd)> the second acceleration G2 (1st) is replaced by the first driving force A> the second driving force B. Can be

Therefore, when the failure of the second clutch solenoid that engages the second clutch K2 is diagnosed during the selection of the second speed stage shown in FIG. 9, the input torque limitation of the driving force with the higher driving force (the second speed stage is selected as the fail-safe control) Step fixed) will be selected.

When the failure of the second clutch solenoid that engages the second clutch K2 is determined during the selection of the third speed, when the input torque is limited while the speed is fixed to the third speed, and when the speed is changed to the third speed, FIG. 10 shows the input torque-acceleration characteristics at the time of shifting restriction from shifting to the first speed.

入力 When the input torque is limited while the shift speed is fixed at the third speed, the acceleration G assuming full-open acceleration with the input torque regulation value is the first acceleration G1 (3rd). On the other hand, when the shift stage is shifted from the third shift stage to the first shift stage selected by the shift limit, and the upper limit input torque at which there is no clutch slip at the first shift stage, the acceleration G becomes the second acceleration G2 (1st). Become. Therefore, comparing the first acceleration G1 (3rd) with the second acceleration G2 (1st), the first acceleration G1 (3rd) <the second acceleration G2 (1st). Since the acceleration G can be replaced by the magnitude of the driving force of the vehicle, the first acceleration G1 (3rd) <the second acceleration G2 (1st) is replaced by the first driving force A <the second driving force B. Can be

Therefore, when the failure of the second clutch solenoid that engages the second clutch K2 is diagnosed during the selection of the third speed stage shown in FIG. 10, the shift limitation of the driving force with the higher driving force (the third speed stage is set as the fail-safe control). To the first gear).

If the second clutch solenoid that engages the second clutch K2 is diagnosed for failure while selecting the fifth speed, when the input torque is limited while the speed is fixed to the fifth speed, and when the speed is changed to the fifth speed, FIG. 11 shows the input torque-acceleration characteristics when the shift from the first gear to the first gear is restricted.

(4) When the input torque is limited while the shift speed is fixed at the fifth speed, the acceleration G assuming full-open acceleration with the input torque regulation value is the first acceleration G1 (5th). On the other hand, when the shift speed is shifted from the fifth speed to the first speed selected by the speed limit, the acceleration G when the upper limit input torque at which there is no clutch slip at the first speed is assumed to be the second acceleration G2 (1st). Become. Therefore, comparing the first acceleration G1 (5th) with the second acceleration G2 (1st), the first acceleration G1 (5th) <the second acceleration G2 (1st). Since the acceleration G can be replaced by the magnitude of the driving force of the vehicle, the first acceleration G1 (5th) <the second acceleration G2 (1st) is replaced by the first driving force A <the second driving force B. Can be

Therefore, if the failure of the second clutch solenoid that engages the second clutch K2 is diagnosed during the selection of the fifth gear shown in FIG. To 1st gear).

[Fail-safe control during running]
FIG. 12 shows various characteristics for explaining the fail-safe control operation of the third brake solenoid for engaging the third brake B3 at the fifth speed in the first embodiment at the time of failure diagnosis during running (other than contamination). Hereinafter, the fail-safe control operation during traveling will be described based on the time chart shown in FIG.

During traveling with the fifth speed selected, the difference between the command current and the actual current (instruction current-actual current) to the third brake solenoid for engaging the third brake B3 at time t1 becomes equal to or greater than the predetermined current, and It is assumed that a 3-brake solenoid failure has occurred.

異常 The abnormality determination timer, which has been rising from time t1, increases, and at time t2 after a predetermined time has elapsed, the abnormality of the third brake solenoid is determined.

Then, the count of the release failure SOL estimation determination timer is started at time t3, and when the release failure SOL estimation determination threshold is reached at time t4, the shift stage of the automatic transmission 3 releases the third brake B3 from the fifth speed. The gear is switched to the sixth speed in which the third clutch K3 is engaged (see FIG. 3). Therefore, at the time t5, the vehicle shifts to the limp home in which the traveling is secured at the sixth speed without using the third brake B3.

As described above, at the time of the time t4 at which the abnormality of the third brake solenoid is determined and the release failure SOL is estimated and determined at the time of the traveling failure diagnosis of the third brake solenoid that engages the third brake B3 at the fifth speed. Shift to the 6th speed stage where the third brake B3 is not used. By performing the fail-safe control, the limp home property is secured.

As described above, in the control device for the automatic transmission 3 according to the first embodiment, the following effects can be obtained.

(1) An automatic transmission 3 that realizes a plurality of shift speeds, a control valve unit 6 that regulates oil pressure to a plurality of friction elements provided in a gear train of the automatic transmission 3, and control of each solenoid included in the control valve unit 6 And a transmission control unit (AT control unit 10) for performing the control.
In the control device of the automatic transmission 3, the hydraulic control circuit of the control valve unit 6 includes a clutch solenoid 20 for individually adjusting the hydraulic pressure supplied to the friction element.
The transmission control unit (AT control unit 10) includes a solenoid failure diagnosis unit 10a for the clutch solenoid 20, a driving force calculation unit 10b for calculating the driving force in the solenoid failure mode, and a fail-safe control unit for taking measures against the solenoid failure mode. 10c.
The solenoid failure diagnosis unit 10a diagnoses a failure mode when a current difference obtained by subtracting an actual current from a command current to the clutch solenoid 20 is equal to or larger than a predetermined current.
When the failure mode is diagnosed, the driving force calculation unit 10b calculates a first driving force A that is obtained when the input torque to the automatic transmission 3 is limited and a gear position that does not use the abnormally diagnosed abnormal clutch solenoid. And the second driving force B obtained when assuming the transition to.
The fail-safe control unit 10c selects the input torque restriction when the first driving force A is equal to or greater than the second driving force B, and selects the gear shift restriction when the first driving force A is less than the second driving force B.
For this reason, when the clutch solenoid 20 of the automatic transmission 3 breaks down, it is possible to prevent the running performance from deteriorating due to future component damage and to prevent the driving force from becoming insufficient during limp home running.
That is, when the actual current to the clutch solenoid 20 is reduced due to a failure, the first driving force A when the input torque limit is selected is compared with the second driving force B when the shift limit is selected. A measure to select the higher fail-safe control is adopted.

(2) The driving force calculation unit 10b calculates the clutch capacity of the friction element that is hydraulically engaged by the actual current to the abnormal clutch solenoid, and determines the input torque regulation value to the automatic transmission 3 according to the calculated clutch capacity. The first driving force A is calculated assuming full-open acceleration with the input torque regulation value.
Therefore, when the clutch solenoid 20 of the automatic transmission 3 fails, the higher the actual current to the abnormal clutch solenoid is, the higher the first driving force A is calculated, and the possibility of selecting the input torque limit is increased. be able to.
That is, the clutch capacity of the friction element hydraulically engaged is determined by the actual current to the abnormal clutch solenoid, the input torque regulation value is determined by the clutch capacity, and the first driving force A is determined by the input torque regulation value.

(3) When the input torque limitation is selected when the first driving force A is equal to or greater than the second driving force B, the fail-safe control unit 10c sets the traveling drive source (engine 1 ), An input torque regulation request for limiting the maximum value of the input torque to the input torque regulation value is output.
For this reason, when the input torque limitation is selected as the fail-safe control, it is possible to reliably suppress the deterioration of the traveling performance at the time of failure.
That is, after shifting to the failure mode in which the input torque limitation is selected as the fail-safe control, the slip of the friction element fastened by the hydraulic pressure from the abnormal clutch solenoid appropriately limits the input torque to the automatic transmission 3. Is surely suppressed. In addition, when the input torque limit is selected, the forced shift is not performed unlike the shift limit, and the uncomfortable feeling given to the occupant can be suppressed.

(4) The driving force calculation unit 10b calculates the shift pattern at the shift speed that does not use the abnormal clutch solenoid, and performs the second drive when assuming the upper limit input torque without clutch slip at the shift speed selected by the shift limitation. Calculate the force B.
Therefore, when the clutch solenoid 20 of the automatic transmission 3 fails, the second driving force B assuming the upper limit input torque is calculated, thereby increasing the possibility of selecting the input torque limit. .
That is, when the second driving force B is calculated without assuming the upper limit input torque, the second driving force B is determined when the speed selected by the speed change restriction is lower than the speed at the time of the clutch solenoid failure diagnosis. Is a large value. That is, when the first driving force A and the second driving force B are compared, the relationship of the first driving force A <the second driving force B is satisfied, and there is no room for selecting the input torque limitation.

(5) The fail-safe control unit 10c forcibly turns off the abnormal clutch solenoid when the first drive force A is less than the second drive force B and the shift restriction is selected.
The speed of the automatic transmission 3 is switched to the speed at which the second driving force B has been calculated.
For this reason, when the shift restriction is selected as the fail-safe control, it is possible to reliably suppress the deterioration of the traveling performance at the time of failure.
That is, when the shift restriction is selected as the fail-safe control, the abnormal clutch solenoid is forcibly turned off, and a shift speed that does not use the abnormal clutch solenoid is selected. As long as the input torque that does not exceed the upper limit input torque is maintained at the shift speed selected by the shift limit, clutch slippage that causes deterioration in running performance can be suppressed.

The control device for an automatic transmission according to the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and changes and additions of the design are permitted without departing from the gist of the invention according to each claim of the claims.

In the first embodiment, as the solenoid failure diagnosis unit 10a, the failure mode is diagnosed when the current difference obtained by subtracting the actual current from the command current to the clutch solenoid 20 is equal to or more than a predetermined current for a predetermined time. However, when the clutch solenoid is diagnosed in the failure mode, the solenoid failure diagnosis unit divides the current into the selected failure mode and the limited failure mode based on the clutch slip threshold value of the actual current, and the actual current falls in the area of the selected failure mode. At some point, an example may be used in which it is determined whether to select the input torque limit or the shift limit based on a comparison between the first driving force and the second driving force.

In the first embodiment, the example of the automatic transmission 3 having nine forward speeds and one reverse speed is described as the automatic transmission. However, the automatic transmission may be an example of an automatic transmission having a stepped gear other than the forward nine speeds and the reverse first speed. Further, in the first embodiment, an example of the control device of the automatic transmission mounted on the engine vehicle has been described. Is possible.

Claims

An automatic transmission for realizing a plurality of shift speeds, a control valve unit for adjusting hydraulic pressure to a plurality of friction elements provided in a gear train of the automatic transmission, and a transmission control for controlling each solenoid included in the control valve unit A control device for an automatic transmission, comprising:
The hydraulic control circuit of the control valve unit has a clutch solenoid that individually adjusts a hydraulic pressure supplied to the friction element,
The transmission control unit includes a solenoid failure diagnosis unit for the clutch solenoid, a driving force calculation unit that calculates a driving force in a solenoid failure mode, and a fail-safe control unit that measures the solenoid failure mode.
The solenoid failure diagnosis unit diagnoses a failure mode when a current difference obtained by subtracting an actual current from a command current to the clutch solenoid is equal to or greater than a predetermined current,
When the drive mode is diagnosed as the failure mode, a first drive force obtained when the input torque to the automatic transmission is assumed to be limited, and a shift speed that does not use the abnormal clutch solenoid diagnosed for failure. And the second driving force obtained when assuming the shift to
The fail-safe control unit selects an input torque limit when the first driving force is equal to or greater than the second driving force, and selects a shift limit when the first driving force is less than the second driving force.
Control device for automatic transmission.
The control device for an automatic transmission according to claim 1,
The driving force calculation unit calculates a clutch capacity of the friction element that is hydraulically engaged by an actual current to the abnormal clutch solenoid, and calculates an input torque regulation value to the automatic transmission according to the calculated clutch capacity. And calculating the first driving force assuming full-open acceleration with the input torque regulation value.
Control device for automatic transmission.
The control device for an automatic transmission according to claim 2,
When the input torque limitation is selected when the first driving force is equal to or greater than the second driving force, the fail-safe control unit may control the input torque from the driving source for traveling while keeping the speed of the automatic transmission unchanged. Outputting an input torque regulation request for limiting the maximum value to the input torque regulation value,
Control device for automatic transmission.
The control device for an automatic transmission according to any one of claims 1 to 3,
The driving force calculation unit calculates a shift pattern at a shift speed that does not use the abnormal clutch solenoid, and calculates the second drive force at an upper limit input torque at which a clutch slip does not occur at a shift speed selected by shift limitation. To calculate,
Control device for automatic transmission.
The control device for an automatic transmission according to claim 4,
The failsafe control unit forcibly turns off the abnormal clutch solenoid when the first drive force is less than the second drive force and the shift restriction is selected,
Switching the gear position of the automatic transmission to a gear position at which the second driving force is calculated;
Control device for automatic transmission.