JP6913255B2 - Control device for automatic transmission - Google Patents

Description

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

Conventionally, there is known a hydraulic control device for a continuously variable transmission that prevents belt slip in the event of an abnormality and enables the vehicle to travel at a minimum (see Patent Document 1). This device is a hydraulic control system in which a solenoid valve generates a duty pressure corrected for the reducing pressure by an electric signal with a constant reducing pressure as a base pressure, and the duty pressure acts on the line pressure control valve to control the line pressure. , A hydraulic clutch is provided in the oil passage of the reducing pressure to detect an abnormality in line pressure control, and when an abnormality occurs, the clutch torque is set below the torque that can be transmitted at the minimum line pressure determined only by the spring force of the line pressure control valve. Restrict.

However, in the above-mentioned conventional device, the clutch torque is limited by the minimum line pressure at the time of detecting an abnormality in the line pressure control. For this reason, the torque transmitted to the drive wheels is limited to the torque determined by the minimum line pressure, which causes a shortage of driving force and may give the driver a sense of discomfort.

Japanese Unexamined Patent Publication No. 62-52260

The present invention has been made by paying attention to the above problems, and when the clutch solenoid of an automatic transmission fails, the driving force becomes insufficient in limp home driving while preventing deterioration of running performance due to future damage to parts. The purpose is to prevent it.

In order to achieve the above object, the control device for the automatic transmission of 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 that individually regulates the hydraulic pressure supplied to the friction element.
The transmission control unit includes a solenoid failure diagnosis unit of 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 measures the solenoid failure mode.
The solenoid failure diagnosis unit diagnoses the failure mode when the current difference obtained by subtracting the actual current from the indicated 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 shifts to the first driving force obtained when the input torque limit to the automatic transmission is assumed and the shift stage that does not use the abnormal clutch solenoid that has been diagnosed as having a failure. The second driving force obtained when is assumed is calculated.
The fail-safe control unit selects the input torque limit when the first driving force is equal to or greater than the second driving force, and selects the shift limit when the first driving force is less than the second driving force.

In this way, when the actual current to the clutch solenoid drops due to a failure, the first driving force when the input torque limit is selected and the second driving force when the shift limit is selected are compared, and the driving force is higher. The policy of selecting the fail-safe control of the one is adopted. As a result, when the clutch solenoid of the automatic transmission fails, it is possible to prevent the driving force from becoming insufficient in the limp home running while preventing the running performance from deteriorating due to future damage to parts.

FIG. 5 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. It is a skeleton diagram which shows an example of the automatic transmission to which the control device of Example 1 was 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 of Example 1 is applied. It is a shift map diagram which shows an example of the shift map in the automatic transmission to which the control device of Example 1 is 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 fail-safe control process at the time of the clutch solenoid failure diagnosis executed by the solenoid failure diagnosis unit, the driving force calculation unit, and the fail-safe control unit of the AT control unit of Example 1. It is explanatory drawing of the effect of the occurrence of erroneous release which shows the influence of the magnitude of the clutch pressure and the possibility of occurrence of erroneous release during clutch engagement by the maximum instruction pressure. It is a relationship characteristic diagram of the SOL monitor current with respect to the SOL instruction current which shows the failure mode in the clutch solenoid failure diagnosis during clutch engagement by the maximum instruction pressure. FIG. 5 is an input torque-acceleration characteristic diagram showing a comparison between the first acceleration and the second acceleration when a failure diagnosis is made for the second clutch solenoid that engages the second clutch during selection of the second speed stage in the first embodiment. FIG. 5 is an input torque-acceleration characteristic diagram showing a comparison between the first acceleration and the second acceleration when a failure diagnosis is made for the second clutch solenoid that engages the second clutch during selection of the third speed stage in the first embodiment. FIG. 5 is an input torque-acceleration characteristic diagram showing a comparison between the first acceleration and the second acceleration when a failure diagnosis is made for the second clutch solenoid that engages the second clutch during the selection of the fifth speed stage in the first embodiment. FIG. 5 is a time chart showing each characteristic for explaining the fail-safe control action at the time of diagnosis of failure during running (other than contamination stick) of the third brake solenoid that fastens the third brake at the fifth speed stage in the first embodiment.

Hereinafter, a mode for implementing the control device for the automatic transmission of the present invention will be described with reference to the first embodiment shown in the drawings.

The control device in the first embodiment is applied to an engine vehicle (an example of a vehicle) equipped with an automatic transmission having 9 forward speeds and 1 reverse speed. 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 "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.

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 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 for the automatic transmission fluid 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 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 AT control unit 10 monitors changes in the operating points (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 of the first embodiment is applied, FIG. 3 is a fastening table for the automatic transmission 3, and FIG. 4 is a speed change with the automatic transmission 3. An example of a map 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 able to connect and disconnect.

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 in which the automatic transmission 3 achieves forward 9th speed and backward 1st speed in the D range by combining three of the six friction elements at the same time. 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 individually controls the fastening pressure, the releasing pressure, and the like for each of the friction elements B1, B2, B3, K1, K2, and K3. In addition, in FIG. 5, it is described that there is one clutch solenoid 20. However, 6 solenoids (1st brake solenoid, 2nd brake solenoid, 3rd brake solenoid, 1st clutch solenoid, 2nd clutch solenoid, 3rd clutch) for each friction element B1, B2, B3, K1, K2, K3. It has a solenoid).

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 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 the driving force in the solenoid failure mode, and a solenoid failure mode. It has a fail-safe control unit 10c to take measures against the above. Here, the solenoid failure diagnosis unit 10a has a SOL monitor current from the solenoid drive circuit 69 (hereinafter referred to as "actual current") and a SOL indicated current output from the AT control unit 10 (hereinafter referred to as "instructed current"). .) And enter. The solenoid drive circuit 69 corrects the current by current feedback control so that the actual current follows the indicated current.

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

When the driving force calculation unit 10b is diagnosed as having a failure mode, the first driving force A obtained when the input torque limit to the automatic transmission 3 is assumed, and the shift stage that does not use the abnormal clutch solenoid that has been diagnosed as having a failure. The second driving force B obtained when the transition to is assumed is calculated.

The driving force calculation unit 10b calculates the clutch capacity of the friction element 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 calculating the driving force when fully open acceleration is assumed with the input torque regulation value. The "driving force when fully open acceleration is assumed with the input torque regulation value" means the upper limit torque (= input) such that the input torque of the automatic transmission 3 becomes the input torque regulation value even when fully open acceleration is performed. It can be rephrased as the driving force when assuming the torque regulation value).

The driving force calculation unit 10b calculates a shift pattern in a shift stage that does not use the abnormal clutch solenoid. Then, when there are a plurality of shift stages that do not use the abnormal clutch solenoid, the lowest shift stage is selected by the shift limit. Then, the second driving force B is obtained by calculating the driving force when the upper limit input torque without clutch slippage is assumed at the selected shift stage.

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.

In the fail-safe control unit 10c, when the first driving force A is the second driving force B or more and the input torque limit is selected, the shift stage of the automatic transmission 3 remains as it is, and the engine 1 (driving drive source) is used. Outputs an input torque regulation request that limits the maximum value of the input torque to the input torque regulation value.

When the first driving force A is less than the second driving force B and the shift limit is selected, the fail-safe control unit 10c forcibly turns off the abnormal clutch solenoid and sets the shift stage of the automatic transmission 3 to the second driving force B. Switches to the calculated shift stage.

[Fail-safe control processing configuration when diagnosing clutch solenoid failure]
FIG. 6 shows the 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 of the first embodiment. Hereinafter, each step of FIG. 6 will be described. The fail-safe control process is executed for the clutch solenoid 20 that regulates the oil pressure to the friction element being engaged while the vehicle is stopped and the vehicle is running in which a predetermined shift stage is selected.

In step S1, following the start or determination of NO in S4 or S9, it is determined whether or not (indicated current-actual current) ≥ predetermined current of the clutch solenoid 20 (= speed change SOL). If YES {(instructed current-actual current) ≥ predetermined current}, the process proceeds to step S2, and if NO {(instructed current-actual current) <predetermined current}, the process proceeds to step S14.

Here, the "predetermined current" is a current value preset as a current deviation determination threshold value for determining that the clutch solenoid 20 is out of order. Further, the "indicated current" is an instructed current for obtaining the maximum pressure when the friction element is being fastened.

In step S2, following the determination in S1 that (instructed current-actual current) ≥ predetermined current, the timer is counted and the process proceeds to step S3.

In step S3, following the timer count in S2, it is determined whether or not the timer indicating the duration for which (instructed current-actual current) ≥ predetermined current is established is equal to or longer than the 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, for a predetermined time, it is prevented from erroneously diagnosing that the clutch solenoid 20 has failed when (instructed current-actual current) ≥ the predetermined current is momentarily established, and the clutch solenoid 20 accurately diagnoses the failure. It is set to a time when it can be done.

In step S4, following the determination in S3 that the timer ≥ the predetermined time, the abnormality of the clutch solenoid 20 diagnosed as the failure mode is confirmed, and the process proceeds to step S5.

In step S5, following the determination of the abnormality in S4, the clutch capacitance 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 is confirmed, and the process proceeds to step S6.

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

In step S6, following the calculation of the clutch capacity in S5, the 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 amount 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 the starting driving force in the failure mode of the clutch solenoid 20, and is obtained by calculating the driving force when fully open acceleration is assumed with the input torque regulation value.

In step S8, following the calculation of the first driving force A in S7, the shift limitation pattern in the shift stage that does not use the abnormal clutch solenoid that has been diagnosed as a failure is calculated, and the process proceeds to step S9.

Here, when there are a plurality of gears that do not use the abnormal clutch solenoid, the lowest gear is selected by shifting.

In step S9, following the calculation of the shift limitation pattern in S8, the second driving force B due to the shift limitation in the shift stage that does not use the abnormal clutch solenoid is calculated, and the process proceeds to step S10.

Here, the second driving force B is the starting driving force in the failure mode of the clutch solenoid 20, and is obtained by calculating the driving force when the upper limit input torque without clutch slippage is assumed at the selected shift stage.

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 judgment result is A ≧ B, the process proceeds to step S11, and if the comparison judgment result is A <B, the process proceeds to step S12.

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

In step S12, following the determination that A <B in S10, the abnormal clutch solenoid is forcibly turned off, the indicated 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, the shift is restricted to select the shift stage in which the abnormal clutch solenoid is not used, and the process proceeds to the end.

In step S14, following the determination in S1 that (instructed 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 separately by dividing it into "background technique", "fail-safe control action at the time of clutch solenoid failure diagnosis", "fail-safe control action while the vehicle is stopped", and "fail-safe control action during running". do.

[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, when the indicated current to the clutch solenoid and the actual current deviate from each other, the solenoid failure diagnosis and fail to select the larger driving force between the driving force assuming the input torque limit and the driving force assuming the shift limit. I decided to incorporate safe processing. The following describes (1) system outline, (2) analysis of the effect of intermediate deviation on the indicated current, and (3) clarification of issues.

(1) 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.

(2) Analysis of the effect of the intermediate deviation on the indicated current If the actual current has an intermediate deviation to the HIGH side with respect to the indicated current to the clutch solenoid, the clutch pressure will be greater than the clutch contacting pressure during clutch release. , Mis-clutch occurs. Therefore, since there is a risk of sudden deceleration due to simultaneous fastening of multiple elements, it is necessary to take measures such as immediately shifting to the shift stage of the evacuation destination based on the failure diagnosis.

On the other hand, when the actual current has an intermediate shift to the LOW side with respect to the indicated current to the clutch solenoid, the actual current is large as shown in FIG. 7, unlike the case where the actual current has an intermediate shift to the HIGH side. The effect changes depending on the situation.
That is, while the clutch is engaged according to the MAX pressure instruction, as shown in FIG. 7, erroneous release does not occur while the clutch pressure is equal to or higher than the actual pressure corresponding to the safety factor of 1.0. However, erroneous release occurs from the time when the clutch pressure is less than the actual pressure corresponding to the safety factor of 1.0 until the clutch cannot be contacted (it is possible to drive, but the driving force is insufficient due to clutch slippage). Further, when the clutch pressure becomes less than the pressure at which the clutch cannot be contacted, the clutch is completely erroneously released (running is impossible).

(3) Clarification of issues The following was clarified from the analysis of the effect of the intermediate deviation on the indicated current. When the actual current deviates to the LOW side with respect to the indicated current (MAX) to the clutch solenoid during clutch engagement, clutch slippage occurs if the safety factor falls below 1.0, but clutch slippage occurs if the safety factor is 1.0 or higher. Does not occur. Therefore, from the effect analysis result, the failure mode in which the current difference obtained by subtracting the actual current from the indicated current to the clutch solenoid 20 is equal to or more than the predetermined current is divided into two failure modes depending on whether or not 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 less than the safety factor of 1.0, the shift limit does not use the abnormal clutch solenoid in order to prevent deterioration of running performance at the time of failure. It becomes the "limited failure mode". However, when the actual current is equal to or higher than the clutch slip threshold and the failure mode has a safety factor of 1.0 or higher, deterioration of running performance due to future damage to parts due to clutch slip is prevented. It becomes a "selective failure mode" in which it is possible to select.

Extracting the problem from the above analysis result, when the actual current is in the region of the "selective failure mode" equal to or higher than the clutch slip threshold value, the degree of freedom of selection of the fail-safe control can be utilized. Therefore, it is intended to ensure the limp home property by selecting either the input torque limit or the shift limit so that the driving force is not insufficient during the limp home running.

[Fail-safe control action when diagnosing clutch solenoid failure]
The present invention has been made by paying attention to the problems extracted in the above (3) Problem clarification. As means for solving the problem, the AT control unit 10 has a solenoid failure diagnosis unit 10a of 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 for countermeasures against the solenoid failure mode. It has a part 10c. The solenoid failure diagnosis unit 10a diagnoses the failure mode when the current difference obtained by subtracting the actual current from the indicated current to the clutch solenoid 20 is equal to or greater than a predetermined current. When the driving force calculation unit 10b is diagnosed as having a failure mode, the first driving force A obtained when the input torque limit to the automatic transmission 3 is assumed, and the shift stage that does not use the abnormal clutch solenoid that has been diagnosed as having a failure. The second driving force B obtained when the transition to is assumed is calculated. 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. It was adopted.

That is, when a predetermined time elapses while the condition (indicated 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, assuming that the shift is limited, the second driving force B is calculated based on the shift stage in which the abnormal clutch solenoid is not used.

In the next S10, the first driving force A and the second driving force B are compared and determined. Then, when the comparison determination result is A ≧ B, the process proceeds to S11, and in S11, 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 comparison judgment result in S10 is A <B, the process proceeds from S12 to S13. In S12, the abnormal clutch solenoid is forcibly turned off. Is done.

As a result, when the clutch solenoid 20 of the automatic transmission 3 fails, it is possible to prevent the driving force from becoming insufficient in the limp home running while preventing the running performance from being deteriorated due to the damage of parts in the future.

That is, when the actual current to the clutch solenoid 20 drops due to a failure, the first driving force A when the input torque limit is selected and the second driving force B when the shift limit is selected are compared, and the driving force is reduced. The higher fail-safe 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 in the limp home running after the failure diagnosis of the clutch solenoid 20. Will be done.

Hereinafter, a comparative judgment between the first driving force A and the second driving force B will be described based on the specific examples shown in FIGS. 9 to 11.

When the failure of the 2nd clutch solenoid that engages the 2nd clutch K2 is diagnosed while the 2nd gear is selected, the input torque is limited while the gear is fixed to the 2nd gear, and the gear is changed from the 2nd gear to 1st gear. The input torque-acceleration characteristics at the time of shifting to the speed limit are as shown in FIG.

When the input torque is limited while the shift stage is fixed to the second speed stage, the acceleration G when fully open acceleration is assumed by the input torque regulation value is the first acceleration G1 (2nd). On the other hand, the acceleration G when the shift stage is shifted from the 2nd gear to the 1st gear selected by the shift limitation and the upper limit input torque without clutch slippage is assumed in the 1st gear is the 2nd acceleration G2 (1st). Become. Therefore, when the first acceleration G1 (2nd) and the second acceleration G2 (1st) are compared, the first acceleration G1 (2nd)> the second acceleration G2 (1st). Since the acceleration G can be replaced with the magnitude of the driving force of the vehicle, the first acceleration G1 (2nd)> the second acceleration G2 (1st) is replaced with the first driving force A> the second driving force B. Be done.

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

If the 2nd clutch solenoid that engages the 2nd clutch K2 is diagnosed as having a failure while the 3rd gear is selected, the input torque is limited while the gear is fixed to the 3rd gear, and the gear is set to the 3rd gear. The input torque-acceleration characteristics at the time of shifting from the first speed to the first speed are as shown in FIG.

When the input torque is limited while the gear is fixed to the 3rd speed, the acceleration G assuming full-open acceleration with the input torque regulation value is the 1st acceleration G1 (3rd). On the other hand, the acceleration G when the shift stage is shifted from the 3rd gear to the 1st gear selected by the shift limitation and the upper limit input torque without clutch slippage is assumed in the 1st gear is the 2nd acceleration G2 (1st). Become. Therefore, when the first acceleration G1 (3rd) and the second acceleration G2 (1st) are compared, the first acceleration G1 (3rd) <the second acceleration G2 (1st). Since the acceleration G can be replaced with the magnitude of the driving force of the vehicle, the first acceleration G1 (3rd) <second acceleration G2 (1st) is replaced with the first driving force A <second driving force B. Be done.

Therefore, when the second clutch solenoid that engages the second clutch K2 is diagnosed as having a failure during the selection of the third speed stage shown in FIG. (Shift to 1st speed) will be selected.

If the second clutch solenoid that engages the second clutch K2 is diagnosed as having a failure while the 5th gear is selected, the input torque is limited while the gear is fixed to the 5th gear, and the gear is set to the 5th gear. The input torque-acceleration characteristics at the time of shifting from the first speed to the first speed are as shown in FIG.

When the input torque is limited while the shift gear is fixed to the 5th gear, the acceleration G assuming full-open acceleration with the input torque regulation value is the first acceleration G1 (5th). On the other hand, the acceleration G when the shift stage is shifted from the 5th speed to the 1st speed selected by the shift limitation and the upper limit input torque without clutch slippage is assumed in the 1st speed is the 2nd acceleration G2 (1st). Become. Therefore, when the first acceleration G1 (5th) and the second acceleration G2 (1st) are compared, the first acceleration G1 (5th) <the second acceleration G2 (1st). Since the acceleration G can be replaced with the magnitude of the driving force of the vehicle, the first acceleration G1 (5th) <second acceleration G2 (1st) is replaced with the first driving force A <second driving force B. Be done.

Therefore, when the second clutch solenoid that engages the second clutch K2 is diagnosed as having a failure during the selection of the 5th speed shown in FIG. (Shift to 1st speed) will be selected.

[Fail-safe control action while driving]
FIG. 12 shows each characteristic for explaining the fail-safe control action at the time of diagnosing a failure during running (other than contamination stick) of the third brake solenoid that fastens the third brake B3 at the fifth speed stage in the first embodiment. Hereinafter, the fail-safe control action during traveling will be described based on the time chart shown in FIG.

While traveling with the 5th speed selected, the difference between the indicated current and the actual current (instructed current-actual current) to the 3rd brake solenoid that fastens the 3rd brake B3 at time t1 becomes equal to or greater than the predetermined current. 3 Suppose that a brake solenoid failure occurs.

The abnormality confirmation timer that had been rising from time t1 rises, and when the predetermined time elapses at time t2, the abnormality of the third brake solenoid is confirmed.

Then, the count of the release failure SOL estimation judgment timer is started from time t3, and when the release failure SOL estimation judgment threshold is reached at time t4, the shift stage of the automatic transmission 3 releases the third brake B3 from the 5th speed stage. It can be switched to the 6-speed stage in which the third clutch K3 is engaged (see FIG. 3). Therefore, at time t5, the vehicle shifts to a limp home that secures running by the 6th speed stage that does not use the 3rd brake B3.

In this way, at the time of the running failure diagnosis of the third brake solenoid that fastens the third brake B3 in the fifth speed stage, the abnormality of the third brake solenoid is confirmed and the release failure SOL is estimated and determined at the timing of time t4. Shift to 6th gear without using the 3rd brake B3. Limp homeness is ensured by performing this fail-safe control.

As described above, in the control device 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.
In the control device of the automatic transmission 3, the hydraulic control circuit of the control valve unit 6 has a clutch solenoid 20 that individually regulates the hydraulic pressure supplied to the friction element.
The transmission control unit (AT control unit 10) includes a solenoid failure diagnosis unit 10a of the clutch solenoid 20, a driving force calculation unit 10b that calculates the driving force in the solenoid failure mode, and a fail-safe control unit that measures the solenoid failure mode. It has 10c and.
The solenoid failure diagnosis unit 10a diagnoses the failure mode when the current difference obtained by subtracting the actual current from the indicated current to the clutch solenoid 20 is equal to or greater than a predetermined current.
When the driving force calculation unit 10b is diagnosed as having a failure mode, the first driving force A obtained when the input torque limit to the automatic transmission 3 is assumed, and the shift stage that does not use the abnormal clutch solenoid that has been diagnosed as having a failure. The second driving force B obtained when the transition to is assumed is calculated.
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.
Therefore, when the clutch solenoid 20 of the automatic transmission 3 fails, it is possible to prevent the driving force from becoming insufficient in the limp home running while preventing the running performance from deteriorating due to the damage of parts in the future.
That is, when the actual current to the clutch solenoid 20 drops due to a failure, the first driving force A when the input torque limit is selected and the second driving force B when the shift limit is selected are compared, and the driving force is reduced. The policy is to select the higher fail-safe control.

(2) The driving force calculation unit 10b calculates the clutch capacity of the friction element hydraulically engaged by the actual current to the abnormal clutch solenoid, and sets the input torque regulation value to the automatic transmission 3 according to the calculated clutch capacity. Calculate and calculate the first driving force A when fully open acceleration is assumed 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, increasing the possibility that the input torque limit is selected. 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 first driving force A is the second driving force B or more and the input torque limit is selected, the fail-safe control unit 10c keeps the shift stage of the automatic transmission 3 as it is and drives the driving source (engine 1). ) Is output as an input torque regulation request that limits the maximum value of the input torque to the input torque regulation value.
Therefore, when the input torque limit is selected as the fail-safe control, it is possible to surely suppress the deterioration of the running performance at the time of failure.
That is, after shifting to the failure mode in which the input torque limit is selected as the fail-safe control, the slip of the friction element engaged by the hydraulic pressure from the abnormal clutch solenoid appropriately limits the input torque to the automatic transmission 3. Is surely suppressed. Further, when the input torque limit is selected, the forced shift is not performed unlike the shift limit, and the discomfort given to the occupant can be suppressed.

(4) The driving force calculation unit 10b calculates the shift pattern in the shift stage that does not use the abnormal clutch solenoid, and assumes the upper limit input torque that does not cause clutch slippage in the shift stage selected by the shift limit. 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, so that the possibility that the input torque limit is selected can be increased. ..
That is, when the second driving force B is calculated without assuming the upper limit input torque, the second driving force B is obtained when the shift stage selected by the shift limitation is the shift stage on the lower side than the shift stage at the time of 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 is that the first driving force A <the second driving force B, and there is no room for selecting the input torque limit.

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

The control device for the automatic transmission of the present invention has 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 Example 1, the solenoid failure diagnosis unit 10a shows an example in which a failure mode is diagnosed when the current difference obtained by subtracting the actual current from the indicated current to the clutch solenoid 20 continues for a predetermined time to be equal to or greater than a predetermined current. However, when the solenoid failure diagnosis unit is diagnosed as having a failure mode, the solenoid failure diagnosis unit classifies the clutch solenoid into a selective failure mode and a limited failure mode based on the clutch slip threshold of the actual current, and the actual current is in the area of the selective failure mode. At one time, it may be an example of deciding whether to select the input torque limit or the shift limit based on the comparison between the first driving force and the second driving force.

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 for an automatic transmission mounted on an engine vehicle is shown, but the present invention is not limited to an engine vehicle, but may be applied as a control device for an automatic transmission such as a hybrid vehicle or an electric vehicle. Is possible.

Claims (5)

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 hydraulic control circuit of the control valve unit has a clutch solenoid that individually regulates the hydraulic pressure supplied to the friction element.
The transmission control unit includes a solenoid failure diagnosis unit of 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 measures the solenoid failure mode.
The solenoid failure diagnosis unit diagnoses the failure mode when the current difference obtained by subtracting the actual current from the indicated 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 has a first driving force obtained when the input torque limit to the automatic transmission is assumed, and a shift stage that does not use the abnormal clutch solenoid that has been diagnosed as having a failure. Calculate the second driving force obtained when assuming the transition 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. In the control device for the automatic transmission according to claim 1,
The driving force calculation unit calculates the clutch capacity of the friction element hydraulically engaged by the actual current to the abnormal clutch solenoid, and calculates the input torque regulation value to the automatic transmission according to the calculated clutch capacity. Then, the first driving force when fully open acceleration is assumed with the input torque regulation value is calculated.
Control device for automatic transmission. In the control device for the automatic transmission according to claim 2.
When the first driving force is equal to or higher than the second driving force and the input torque limit is selected, the fail-safe control unit keeps the shift stage of the automatic transmission as it is and receives the input torque from the traveling drive source. Outputs an input torque regulation request that limits the maximum value to the input torque regulation value.
Control device for automatic transmission. In the control device for the automatic transmission according to any one of claims 1 to 3.
The driving force calculation unit calculates a shift pattern in a shift stage that does not use the abnormal clutch solenoid, and assumes an upper limit input torque that does not cause clutch slippage in the shift stage selected by the shift limit. To calculate,
Control device for automatic transmission. In the control device for the automatic transmission according to claim 4,
When the first driving force is less than the second driving force and the shift limit is selected, the fail-safe control unit forcibly turns off the abnormal clutch solenoid.
The shift stage of the automatic transmission is switched to the shift stage in which the second driving force is calculated.
Control device for automatic transmission.

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