JP2010236605A - Control device of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of automatic transmission which makes a speed change shock worsen at the time of speed change when the automatic transmission fails. <P>SOLUTION: This control device performs fail safe control (S101) when a failure occurs in the automatic transmission equipped with a plurality of gear stages (S100). Furthermore, this device outputs a speed change command (S102) so as to make speed change by supplying a hydraulic pressure to a fastening-side clutch based on a fastening-side compensating command pressure obtained by adding a fastening-side hydraulic pressure compensating amount to a fastening side command pressure when speed change is made during fail-safe control if an acceleration G is determined to be smaller than a predetermined acceleration Gk during fail-safe control (S105). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  Conventionally, Patent Document 1 discloses a technique for prohibiting shifting to a predetermined gear position when sensors or friction elements in an automatic transmission fail. Also, in the same case, Patent Document 2 discloses a device that is fixed to a predetermined gear position.

JP-A-8-159269 JP 2000-223830 A

  In general, when a failure such as that described above occurs, the warning light on the inner panel is displayed to notify the driver of the failure, prompting the driver to bring the vehicle to a repair shop. Unfamiliar drivers may not notice the warning light. In addition, for example, if a vehicle that runs only on a road that runs at a relatively low speed causes a failure of the automatic transmission and the gear position is fixed at a predetermined gear position, the gear position is fixed during normal driving. In some cases, you may not notice the difference in driving performance.

  In such a case, there is a problem that repair of the failed part is delayed and the failed part is enlarged.

  The present invention was invented to solve such problems, and when the sensors and friction elements of the automatic transmission failed, the driver noticed early that the failure occurred, It aims at suppressing the expansion of a part.

  The present invention provides a control device for an automatic transmission that has a plurality of shift speeds achieved by engaging and releasing a friction element, and controls an automatic transmission that shifts and outputs rotation from a drive source. A failure detection means for detecting a failure, a failure-time control means for controlling a shift speed to be used when a failure is detected by the failure detection means, and a shift shock generated when the shift speed is switched by the failure-time control means is evaluated. And a shift shock worsening means for worsening the shift shock when the shift shock is evaluated to be smaller than a predetermined shock.

  According to the present invention, when the automatic transmission breaks down and travels while limiting the use of the shift speed, if it is evaluated that the shift shock during the shift is smaller than the predetermined shift shock, the shift shock generated during the shift is generated. As a result, the driver can be notified that the automatic transmission is out of order, and the expansion of the failed part can be suppressed.

It is a skeleton figure which shows the structure of the automatic transmission of 1st Embodiment. It is a figure which shows the relationship between the selection gear stage of an automatic transmission, and a fastening theory. It is a flowchart which shows the control when a failure generate | occur | produces in the automatic transmission of 1st Embodiment. 4 is a time chart showing a change in hydraulic pressure of a clutch when a failure occurs in the automatic transmission according to the first embodiment. It is a flowchart which shows the control when a failure generate | occur | produces in the automatic transmission of 2nd Embodiment. It is a time chart which shows the oil pressure change of a clutch, etc. when a failure occurs in an automatic transmission of a 2nd embodiment. It is a flowchart which shows the control when a failure generate | occur | produces in the automatic transmission of 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  In the present embodiment, the shift shock is an uncomfortable feeling that the driver feels due to the deterioration of drivability during shifting of an automatic transmission having a plurality of shift speeds, and the small (good) shift shock is driving during shifting. The discomfort felt by the driver is small, and the shift shock is large (bad) when the discomfort felt by the driver during the shift is large. Usually, automatic transmissions are designed so that the shift shock is reduced. For example, when the shift shock is bad, for example, when the fluctuation amount of the output shaft torque of the automatic transmission caused by the release and engagement of the clutch is large, when the fluctuation amount of the output shaft torque per hour is large, This is a case where the engine speed rapidly increases and the engine blows idle even though the clutch is not completely engaged, or the output shaft torque fluctuates due to the engine blown.

  FIG. 1 is a skeleton diagram showing the configuration of the automatic transmission according to the first embodiment of the present invention.

  The engine (drive source) 1 is adjusted in output by a throttle valve that increases in opening from fully closed to fully open as the accelerator pedal operated by the driver is depressed. Then, it is assumed that the signal is input to the input shaft 4 of the automatic transmission 2.

The automatic transmission 2 is provided with a front planetary gear set 6 and a rear planetary gear set 7 sequentially placed on the input / output shafts 4 and 5 arranged in a coaxial butting relationship from the engine 1 side, and these are planets in the automatic transmission 2. The main component of the gear transmission mechanism. The front planetary gear set 6 close to the engine 1 is a simple planetary gear set comprising a front sun gear S _F , a front ring gear R _F , a front pinion P _F meshing with these, and a front carrier C _F that rotatably supports the front pinion. distant rear planetary gear set 7 from the engine 1 is also rear sun gear S _R, rear ring gear R _R, and these meshes rear pinion P _R, and simple planetary gear set consisting of a rear carrier C _R for rotatably supporting the rear pinion.

Friction elements that determine the transmission path (speed stage) of the planetary gear transmission mechanism include low clutch L / C, 2nd and 4th brake 2-4 / B, high clutch H / C, low reverse brake LR / B, low The one-way clutch L / OWC and the reverse clutch R / C are provided in correlation with the components of the planetary gear sets 6 and 7 as follows. In other words, the front sun gear S _F is thereby suitably be coupled to the input shaft 4 by the reverse clutch R / C, suitably fixable to the second speed-fourth speed brake 2-4 / B.

The front carrier C _F can be appropriately coupled to the input shaft 4 by the high clutch H / C. Further, the front carrier C _F is prevented from rotating in the direction opposite to the engine rotation by the low one-way clutch L / OWC and can be appropriately fixed by the low reverse brake LR / B. The front carrier C _F and the rear ring gear R _R can be appropriately coupled by the low clutch L / C. Between front ring gear R _F and the rear carrier C _R bonded to each other, these front ring gear R _F and the rear carrier C _R is connected to the output shaft 6 is coupled to the input shaft 4 of the rear sun gear S _R.

  The power transmission train of the planetary gear speed change mechanism includes a selective hydraulic operation (fastening) indicated by a solid line ◯ in FIG. 2 of the friction elements L / C, 2-4 / B, H / C, LR / B, and R / C. ) And the self-engagement of the low one-way clutch L / OWC indicated by a solid line ◯ in the same figure, forward first speed (1st), forward second speed (2nd), forward third speed (3rd), forward The fourth forward speed (4th) forward speed and the reverse speed (Rev) can be obtained. Note that the hydraulic operation (fastening) indicated by the dotted circles in FIG. 2 is a friction element to be operated when engine braking is necessary.

  The engagement logic of the shift control friction elements L / C, 2-4 / B, H / C, LR / B, and R / C shown in FIG. 2 is realized by the control valve body 8 shown in FIG. In addition to a manual valve (not shown), a line pressure solenoid 9, a low clutch solenoid 10, a second speed / fourth speed brake solenoid 11, a high clutch solenoid 12, a low reverse brake solenoid 13, and the like are inserted into the valve 8.

  The line pressure solenoid 9 switches the line pressure, which is the original pressure of the shift control, by turning on and off, and a manual valve (not shown) is driven forward by the driver according to the desired travel mode (D) range position, It is assumed that the vehicle is operated to the reverse travel (R) range position or the parking / stop (P, N) range position.

  In the D range, the manual valve corresponds to the low clutch L / C by controlling the duty of the low clutch solenoid 10, the second / fourth speed brake solenoid 11, the high clutch solenoid 12, and the low reverse brake solenoid 13 using the above line pressure as a source pressure. Line pressure is supplied to a predetermined circuit so that the hydraulic pressures of the 2nd and 4th brakes 2-4 / B, the high clutch H / C, and the low reverse brake LR / B can be individually controlled, and the duty of each solenoid It is assumed that the first to fourth speed engagement logic shown in FIG. 2 is realized by the control.

  However, in the R range, the manual valve supplies the line pressure directly to the reverse clutch R / C and the low reverse brake LR / B without depending on the duty control of each solenoid, and the engagement is performed in FIG. Assume that the reverse logic shown is implemented. In the P and N ranges, the manual valve does not supply the line pressure to any circuit, and the automatic transmission is neutralized by releasing all the friction elements.

  The ON / OFF control of the line pressure solenoid 9 and the duty control of the low clutch solenoid 10, the second / fourth speed brake solenoid 11, the high clutch solenoid 12, and the low reverse brake solenoid 13 are executed by the transmission controller 14, respectively. The transmission controller 14 detects a signal from a throttle opening sensor 15 that detects the throttle opening TVO of the engine 1 and a turbine rotation speed Nt that is an output rotation speed (transmission input rotation speed) of the torque converter 3. A signal from the turbine rotation sensor 16, a signal from the output rotation sensor 17 for detecting the rotation speed No. of the output shaft 5 of the automatic transmission 2, a signal from the inhibitor switch 18 for detecting the selected range, and fastening at the time of the change gear change. Fastening side friction element to be realized, that is, clear from FIG. High clutch H / C for 2 → 3 shift, 2 → 4th brake 2-4 / B for 2 → 3 shift, 2nd / 4th brake 2-4 / B for 3 → 4 shift, At the time of 4 → 3 shift, a signal from the hydraulic switch 60 disposed in the low clutch L / C is input.

  The transmission controller 14 executes a control program (not shown), and from the throttle opening TVO and the transmission output rotational speed No (vehicle speed) based on the planned shift map according to the signal from the inhibitor switch 18, A suitable gear position required in the driving state is searched.

  Next, the transmission controller 14 determines whether or not the currently selected shift speed is coincident with the preferred shift speed. If they are not coincident, a shift command is issued and the shift to the preferred shift speed is executed, that is, in FIG. Based on the engagement logic table, the hydraulic pressure of the friction element is changed by duty control of the solenoids 10 to 13 so that the engagement and release of the friction element for the speed change are performed.

  Further, the transmission controller 14 determines whether a failure has occurred in the automatic transmission 2 based on signals from the sensors, the hydraulic switch 60, etc., and if a failure has occurred in the automatic transmission 2, The control described below is executed.

  Next, the control in this embodiment when a failure occurs in the automatic transmission 2 will be described with reference to the flowchart of FIG. This flowchart is always repeated during traveling.

  In step S100 (failure detection means), it is determined whether or not a failure has occurred in the automatic transmission 2. The failure of the automatic transmission 2 means that, for example, when a signal from the hydraulic switch 60 is not a normal signal because the hydraulic pressure for realizing a certain gear stage cannot be supplied and discharged by a valve stick, the turbine rotation sensor 16 or the output rotation sensor 17 is disconnected. When a failure has occurred in the automatic transmission 2, it is determined that the automatic transmission 2 cannot be normally controlled, and the process proceeds to step S101. Further, when there is no failure in the automatic transmission 2, this control is terminated.

  In step S101 (failure control means), fail-safe control is started. The fail-safe control is, for example, control for fixing a gear position to a predetermined gear position, or control for prohibiting gear shifting to a gear position where a failure has occurred. If it is determined that a failure has occurred in the automatic transmission 2, fail safe control is performed, thereby enabling the vehicle to travel under certain conditions while suppressing the failure expansion of the automatic transmission 2. When fail-safe control is started, a warning lamp is lit on the inner panel to notify the driver that the automatic transmission 2 has failed.

  In step S102, it is determined whether or not a shift command has been issued to the automatic transmission 2 by the operation of fail-safe control. When a gear change command is issued, the process proceeds to step S103. Even when fail-safe control is performed, for example, in the case of control for fixing the shift speed, a shift command is issued so that the shift is executed from the current shift speed to the fixed shift speed. In addition, in the case of control for prohibiting a shift to a gear stage in which a failure has occurred, a shift can be performed between gear stages other than the gear stage in which a failure has occurred, for example, depending on operating conditions such as throttle opening and vehicle speed. Based on this, a shift command is issued.

  During fail-safe control, a shift is executed based on this shift command. The speed change is constituted by a torque phase and an inertia phase. The torque phase refers to the transfer of torque from a clutch (hereinafter referred to as a disengagement side clutch) that is engaged by a shift (hereinafter referred to as a disengagement side clutch) that is disengaged by the speed change after the automatic transmission 2 starts a gear shift. Is the state until the hydraulic pressure of the disengagement side clutch becomes substantially zero. In addition, the inertia phase refers to a state in which a rotational change occurs after the torque phase and the relative rotational difference of the engagement side clutch disappears.

  In normal gear shifting during fail-safe control, in the torque phase, the hydraulic pressure of the release side clutch is discharged based on a preset release side hydraulic command, and the hydraulic pressure of the engagement side clutch is based on a preset engagement side hydraulic command. Supplied. The engagement side hydraulic pressure command becomes a relatively high precharge pressure in order to quickly reduce the piston stroke in the engagement side clutch immediately after the start of shifting. When the precharge of the engagement side clutch is completed, the engagement side command pressure once becomes a hydraulic pressure lower than the precharge pressure, and increases from the hydraulic pressure with a predetermined gradient according to the engine torque. The fastening completion hydraulic pressure increases with a greater gradient than before.

  When the failure notification of the automatic transmission 2 is performed during the fail safe control, the engagement side hydraulic pressure correction amount set in step S105 described later is added to the engagement side command pressure that is normally set after the precharge is completed. Shifting is executed based on the engagement side correction command pressure. The engine torque at the time of shifting is a corrected engine torque obtained by adding an engine torque correction amount set in step S105 described later to the engine torque corresponding to the accelerator opening of the driver.

  Shifting is completed in a short time by supplying the hydraulic pressure of the engagement side clutch based on the engagement side correction command pressure during the fail safe control. Therefore, the shift shock becomes large. By increasing the shift shock during the shift, it is possible to let the driver know that the automatic transmission 2 has failed. Further, by setting the engine torque as the corrected engine torque during the fail safe control, the fluctuation amount of the output shaft torque when switching from the torque phase to the inertia phase, so-called pulling shock, can be increased. Further, the fluctuation amount of the output shaft torque after the start of the inertia phase, that is, the so-called push-up shock can be increased. Thus, for example, even when the driver is unaware of the warning light on the inner panel, by increasing the shift shock, it is possible to experience and notify that a failure has occurred in the automatic transmission 2. is there.

  In step S103, it is determined whether or not a notification control end flag described later in detail is “1”. If the notification control end flag is “1”, the present control is once ended. If the notification control end flag is “0”, the process proceeds to step 104.

  In step S104 (shifting shock evaluating means), an acceleration G at the time of shifting is calculated, and the calculated acceleration G is compared with a predetermined acceleration (predetermined shock) Gk. If the acceleration G is smaller than the predetermined acceleration Gk, it is determined that the shift shock felt by the driver during the shift is small, and the process proceeds to step S105. On the other hand, if the acceleration G is greater than the predetermined acceleration Gk, it is determined that the shift shock felt by the driver during a shift is large, and the routine proceeds to step 106.

  The acceleration G is calculated by calculating the rate of change per unit time of the turbine rotation Nt detected by the turbine rotation sensor 16 at the time of shifting. When the acceleration G is smaller than the reference rate of change, the shift shock is small, and when it is large, the shift shock is small. You may determine with it being large. The acceleration G may be calculated by providing an output shaft torque sensor and calculating the rate of change of the output shaft torque at the time of shifting. The predetermined acceleration Gk is an acceleration set in advance, and is an acceleration that is estimated to ensure that the driver feels uncomfortable at the time of shifting.

  In step S105 (hydraulic pressure increasing means, torque increasing means), since the shift shock at the time of shift during fail-safe control is small, the driver is informed that the automatic transmission 2 has failed at the next shift. Therefore, the engagement side hydraulic pressure correction amount and the engine torque correction amount to be used are set.

  The engagement side hydraulic pressure correction amount is set by adding a predetermined value to the currently set engagement side hydraulic pressure correction amount. That is, every time it is determined in step S104 that the acceleration G is smaller than the predetermined acceleration Gk, a predetermined value is added as the engagement side hydraulic pressure correction amount. When the first shift is executed by the fail-safe control in step 101, the engagement side hydraulic pressure correction amount is set to zero as an initial value. If the predetermined value is too large, the shift shock may suddenly increase, and if the predetermined value is small, the shift shock does not increase and the driver may not notice that the automatic transmission 2 has failed. is there. For this reason, the predetermined value is a value that is appropriately set by experiment or the like. Similarly, the engine torque correction amount is also a preset value.

  By using the engagement side hydraulic pressure correction amount and the engine torque correction amount set in step S105, the input torque is increased and the hydraulic pressure of the engagement side clutch is increased from the previous time, so that the shift shock at the next shift is increased. To do. As a result, the driver can be notified of the fact that the automatic transmission 2 is out of order.

  In this embodiment, the engagement side hydraulic pressure correction amount and the engine torque correction amount are set. However, only the engagement side hydraulic pressure correction amount may be set to increase the shift shock at the next shift.

  In step S106, "1" is added to the value of the counter that measures the number of times that the vehicle acceleration G at the time of shifting is greater than the predetermined acceleration Gk, the counter value is updated, and the routine proceeds to step 107.

  In step S107 (shifting shock deterioration prohibiting means), the value of the counter is compared with a predetermined number of times. When the counter value reaches the predetermined number of times, a relatively large shift shock is generated during the shift, and the driver is notified the predetermined number of times that the automatic transmission 2 has failed, the process proceeds to step S108. If the value of the counter is not a predetermined value and the driver has not been notified a predetermined number of times that the automatic transmission 2 is out of order, the process is terminated and this control is repeated again. The predetermined number of times is a preset number of times. By generating a relatively large shift shock a predetermined number of times during a shift, the driver can be surely experienced and notified that the automatic transmission 2 has failed. The counter value is not automatically reset even when the vehicle stops and the key switch is turned off. That is, once it is determined in step S100 that the automatic transmission 2 is out of order, the counter value is accumulated until a predetermined number of times, and is not reset unless it is intentionally reset at a repair shop, for example. Absent.

  In step S108 (shift shock deterioration prohibiting means), the driver is informed that the automatic transmission 2 has failed by giving the driver a relatively large shift shock during the shift in the control in the above step. Both the hydraulic pressure correction amount and the engine torque correction amount are set to zero. Thus, from the next shift, the hydraulic pressure of the engagement side clutch is supplied based on the normal engagement side hydraulic pressure command even during the fail safe control. Further, the engine torque becomes a normal engine torque even during fail-safe control. Therefore, the shift shock at the time of shifting becomes small, and drivability can be improved. In step 109, the notification control end flag is changed from “0” to “1”.

  By the above control, when the automatic transmission 2 breaks down, it is possible to notify the driver that the automatic transmission 2 has failed by increasing the shift shock during shifting.

  Next, changes in the hydraulic pressure of the clutch when a failure occurs in the automatic transmission 2 will be described with reference to the time chart of FIG. Here, a case will be described in which the automatic transmission 2 fails, an upshift is performed by fail-safe control, the engagement side correction command pressure and the correction engine torque are set, and the acceleration G is greater than the predetermined acceleration Gk. In FIG. 4, the case where the control of this embodiment is not used is indicated by a broken line. Here, description will be made using a hydraulic pressure command value as a change in hydraulic pressure of the clutch.

  At time t0, a shift determination is made and the shift is started. Specifically, first, discharge of the hydraulic pressure of the release side clutch is started. Further, a precharge pressure is supplied in order to end the piston stroke of the clutch on the engagement side early. The engine torque is a corrected engine torque obtained by adding the engine torque correction amount, and the engine torque becomes larger than that at the time of normal shifting.

  When the command for the precharge pressure of the engagement side clutch ends at time t1, the engagement side correction command pressure obtained by adding the engagement side hydraulic pressure correction amount to the engagement side command pressure set during normal fail-safe control. And Thereby, the hydraulic pressure of the engagement side clutch becomes higher than the normal hydraulic pressure.

  At time t2, the piston stroke of the engagement side clutch is completed and the torque phase is started.

  At time t3, when the hydraulic pressure of the disengagement side clutch becomes substantially zero and reaches the hydraulic pressure corresponding to the torque that the engagement side clutch should share, the torque phase ends and the inertia phase starts. Since the engine torque is increased at this time, the amount of fluctuation of the output shaft torque when switching from the torque phase to the inertia phase increases, and the pulling shock increases. In addition, the amount of fluctuation of the output shaft torque after the start of the inertia phase increases, and the push-up shock increases.

  When the inertia phase ends at time t4, the hydraulic pressure is increased with a larger gradient, and the shift control ends at time t5. In the present embodiment, since the hydraulic pressure is supplied based on the engagement side correction command pressure, the time from when the shift command is issued until the inertia phase is completed is shortened. During this time, the output shaft torque fluctuates as described above. Therefore, the amount of fluctuation of the output shaft torque per hour increases, and the shift shock felt by the driver during the shift increases.

  The effect of 1st Embodiment of this invention is demonstrated.

  When the automatic transmission 2 breaks down and performs fail-safe control, the shift shock at the previous shift is evaluated, and when the shift shock is small, the shift shock at the next shift is increased. The driver can be notified by experiencing that the automatic transmission 2 has failed. Therefore, the driver can be made aware that the automatic transmission 2 is out of order, prompt repair by a repair shop or the like, and prevent the failure part from expanding (corresponding to claim 1).

  Since the shift shock is evaluated when fail-safe control is started, the driver is notified early that the automatic transmission 2 is out of order, so that the deterioration of drivability for a long time is suppressed. (Corresponding to claim 1).

  When the acceleration G is smaller than the predetermined acceleration Gk at the time of gear shifting during fail-safe control, the gear shifting shock is increased from the time of the next gear shifting, thereby suppressing the gear shifting shock from becoming too large and excessive drivability. Can be suppressed (corresponding to claim 1).

  By increasing the hydraulic pressure of the clutch on the engagement side during shifting during fail-safe control from the previous hydraulic pressure, the time from the start to the end of shifting is shortened, and the fluctuation amount of the output shaft torque per time is increased. Thus, the shift shock can be increased with certainty, and the driver can be surely felt that the automatic transmission 2 has failed during the shift (corresponding to claim 2).

  By increasing the engine torque at the time of gear shifting during fail-safe control, it is possible to increase the pulling shock when switching from the torque phase to the inertia phase, and to increase the push-up shock during the inertia phase. As a result, the shift shock can be reliably increased, and the driver can be surely experienced that the automatic transmission 2 has failed during the shift. In particular, even when the torque of the input shaft 4 is small, for example, when the accelerator pedal opening is OFF, by increasing the engine torque, the driver can experience a shift shock at the time of a shift. It is possible to reliably notify that the transmission 2 is out of order (corresponding to claim 3).

  Count the number of times that the shift shock has become large during gear shifting during fail-safe control, and if the counter value reaches the specified number of times, both the engagement side hydraulic pressure correction amount and the engine torque correction amount are set to zero. Thus, it is possible to prevent the state in which the shift shock has deteriorated from continuing for a long time, and to suppress excessive deterioration in drivability (corresponding to claim 6).

  By calculating the acceleration G from the rate of change of the turbine rotation Nt per unit time, it is possible to accurately detect the fluctuation of the shift shock and to perform this control appropriately (corresponding to claim 7).

  Next, a second embodiment of the present invention will be described.

  The second embodiment is different from the first embodiment in control when a failure occurs in the automatic transmission 2. Here, control when a failure occurs in the automatic transmission 2 will be described with reference to the flowchart of FIG.

  In the second embodiment, step S202 and step S205 are different from those of the first embodiment, and the other control is the same. Therefore, the control in step S202 and step S205 will be described here.

  In the present embodiment, engine torque down control is performed to temporarily reduce engine torque at the time of shifting and to reduce shift shock at the time of shifting. Normally, the engine torque down control reduces the engine torque when starting the inertia phase and returns the engine torque during the inertia phase.

  In step S202 (torque down means), it is determined whether or not a shift command has been issued to the automatic transmission 2 by the operation of fail-safe control. When a gear shift command is issued, the process proceeds to step S203.

  During fail-safe control, a shift is executed based on a shift command. Further, the engine torque down control is executed even during the fail safe control. When the failure notification of the automatic transmission 2 is performed during the fail safe control, the engine torque is returned during the inertia phase. The engine torque is returned to a torque corresponding to the accelerator opening in a stepwise manner.

  When the engine torque recovers (increases) during the inertia phase, a shift shock is generated at a timing that does not normally occur, and the driver is notified that the automatic transmission 2 has failed.

  In step S205, the engagement side hydraulic pressure correction amount is calculated and set. The setting method of the engagement side hydraulic pressure correction amount is the same as that in step S105.

  In this embodiment, the engagement side hydraulic pressure correction amount is set. However, a shift shock may be generated by returning the engine torque during the inertia phase without setting the engagement side hydraulic pressure correction amount.

  Next, a change in the hydraulic pressure of the clutch when a failure occurs in the automatic transmission 2 will be described with reference to the time chart of FIG. Although the conditions of the automatic transmission 2 are the same as the conditions in the first embodiment, FIG. 4 is a time chart showing the change in acceleration instead of the change in the input shaft torque in the first embodiment.

  If there is a shift command at time t0, the shift is started.

  When the command for the precharge pressure of the engagement side clutch ends at time t1, the engagement side correction command pressure obtained by adding the engagement side hydraulic pressure correction amount to the engagement side command pressure set during normal fail-safe control. And

  At time t2, the piston stroke of the engagement side clutch is completed and the torque phase is started.

  At time t3, when the torque phase is completed and the hydraulic pressure corresponding to the torque to be shared by the engagement side clutch is reached, the inertia phase is started. As a result, engine torque down control is started, and the engine torque is reduced so as to cancel the inertia torque generated with the change in rotation.

  At time t4, the engine torque down control is terminated during the inertia phase, and the engine torque is returned to the engine torque corresponding to the accelerator opening in a stepped manner. As a result, the output shaft acceleration of the vehicle increases during the inertia phase, and the driver feels as a shift shock.

  When the inertia phase ends at time t5, the hydraulic pressure is increased with a larger gradient, and the shift control ends at time t6.

  The effect of 2nd Embodiment of this invention is demonstrated. In addition to the effects described in the first embodiment, the following effects are provided.

  Engine torque down control is performed during gear shifting during failsafe control, and engine torque is restored during the inertia phase. Thus, a push-up shock is generated during the shift at a timing that does not occur in the normal shift, so that the driver can feel the shift shock and can notify that the automatic transmission 2 is malfunctioning. Corresponding).

  Next, a third embodiment of the present invention will be described.

  The third embodiment differs from the first embodiment in control when a failure occurs in the automatic transmission 2. Here, control when a failure occurs in the automatic transmission 2 will be described with reference to the flowchart of FIG.

  In the third embodiment, step S304 and step S305 are different from the first embodiment.

  In step S304, the engine blow amount is detected. Specifically, an increase amount of the engine speed is detected from the start to the end of the shift, and it is determined whether the increase amount is equal to or greater than a predetermined increase amount Nk. When the increase amount is equal to or greater than the predetermined increase amount Nk, the process proceeds to step 306, and when it is less than the predetermined increase amount, the process proceeds to step S305.

  In step S305 (engagement timing delay means), the engagement side hydraulic pressure correction amount is subtracted from the oil pressure at the current shift, particularly after the precharge pressure, so that the engagement timing of the engagement side clutch at the next shift is delayed. . As a result, the rise of the engagement-side clutch is delayed with respect to the decrease in the hydraulic pressure of the release-side clutch, so that the transmission capacity becomes insufficient and the engine speed is idle. Therefore, it is possible to notify the driver that the automatic transmission 2 is out of order.

  In this embodiment, the next engagement-side correction command pressure is calculated by subtracting the engagement-side oil pressure correction amount from the current engagement-side oil pressure command. However, the present invention is not limited to this, and for example, the engagement-side command pressure The capacity of the engagement-side clutch may be made short by keeping the hydraulic pressure lower than the engagement completion hydraulic pressure for a certain time.

  In step S305, the engagement side hydraulic pressure correction amount is set so that the engagement timing of the engagement side clutch at the next shift is delayed. The setting method of the engagement side hydraulic pressure correction amount is the same as that in step S105. In this embodiment, the engagement side hydraulic pressure correction amount is set by adding a predetermined amount to the currently set engagement side hydraulic pressure correction amount, so that the engagement side correction command pressure is reduced and the engagement side clutch hydraulic pressure is completely engaged. It takes longer to reach hydraulic pressure.

  Next, effects of the third exemplary embodiment of the present invention will be described. In addition to the effects described in the first embodiment, the following effects are provided.

  If the shift shock during the current shift during fail-safe control is small, the engagement timing of the disengagement clutch is increased when the shift is performed during fail-safe control by delaying the engagement timing of the engagement clutch. Since the delay is delayed, the transmission capacity becomes insufficient, the engine rotation speed increases rapidly, the engine blows, and the driver can be notified that the automatic transmission 2 has failed. (Corresponding to claim 5).

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

1 Engine (drive source)
2 Automatic transmission 14 Transmission controller

Claims (8)

In a control device for an automatic transmission that has a plurality of shift speeds achieved by fastening and releasing a friction element, and controls an automatic transmission that shifts and outputs rotation from a drive source,
A failure detection means for detecting a failure of the automatic transmission;
When a failure is detected by the failure detection means, a failure time control means for controlling the shift speed to be used;
A shift shock evaluating means for evaluating a shift shock generated when the shift stage is switched by the failure-time control means;
A control device for an automatic transmission, comprising: a shift shock aggravating means that worsens the shift shock when the shift shock evaluation means evaluates that the shift shock is smaller than a predetermined shock. The shift shock aggravating means is
2. The control device for an automatic transmission according to claim 1, wherein the control device is an oil pressure increasing means for increasing the hydraulic pressure of the engagement side friction element at the next shift than the hydraulic pressure of the engagement side clutch at the current shift.   3. The control device for an automatic transmission according to claim 2, wherein the shift shock aggravating means includes torque increasing means for increasing the torque of the drive source during shifting.   3. The shift shock aggravating means comprises torque reduction means for temporarily reducing the torque of the drive source during the shift and returning it during the inertia phase. The automatic transmission control device described.   The automatic shift shock deterioration means is an engagement timing delay means for delaying the engagement timing of the engagement side friction element at the next shift from the engagement timing at the current shift. Transmission control device.   The automatic shift according to any one of claims 1 to 5, further comprising a shift shock deterioration prohibiting unit that operates the shift shock deterioration unit a predetermined number of times and prohibits the operation after the predetermined number of operations. Machine control device.   7. The control device for an automatic transmission according to claim 1, wherein the shift shock evaluation unit evaluates based on a rate of change of an input shaft rotation speed of the automatic transmission.   The control device for an automatic transmission according to any one of claims 1 to 6, wherein the transmission shock evaluation means evaluates based on a fluctuation amount of an output shaft torque of the automatic transmission.

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