JP4830481B2 - Shift control device for automatic transmission - Google Patents

Description

  The present invention relates to shift control of an automatic transmission, and more particularly to shift control when an automatic transmission breaks down and falls into a neutral state (power non-transmission state).

  An automatic transmission mounted on a vehicle combines a torque converter and a gear-type transmission mechanism, and selectively engages and releases a plurality of friction engagement elements such as a clutch and a brake on a power transmission path of the gear-type transmission mechanism. By switching to any of the above, the gear stage is automatically set according to the operating state. The automatic transmission is provided with a hydraulic control circuit that controls supply of operating pressure to the friction engagement elements to engage or release them.

  In this case, the hydraulic pressure control circuit is configured to control the operating pressure supplied to each friction engagement element to execute gear stage control, that is, shift control. Various solenoid valves for generating, supplying and discharging, pressure regulation, and the like are provided. These solenoid valves control the operation pressure supplied to the friction engagement elements and the like by controlling the operation by an electric control signal.

  Incidentally, in the automatic transmission having such a configuration, a failure may occur in the solenoid valve. As such a failure, it is conceivable that the solenoid valve does not operate correctly due to an electrical failure such as a disconnection or a short circuit in the solenoid valve, or a mechanical failure such as a seal failure due to the sticking (fixing) of the plunger or foreign matter. When such a failure occurs, a desired frictional engagement element is not engaged with a shift command that is output in accordance with the driving state, so that the gear stage according to the command is not formed, and the gear-type transmission mechanism is in neutral. It may fall into a state.

  Japanese Patent Laid-Open No. 11-280898 (Patent Document 1) discloses a fail-safe control for prohibiting a gear stage in which a failure is detected and changing to another gear stage as a countermeasure when a failure occurs in an automatic transmission. A control device for an automatic transmission that appropriately and rationally performs the fail-safe control when performing the above is disclosed. The automatic transmission control device includes a torque converter, a gear-type transmission mechanism to which power from the engine is input via the torque converter, a plurality of friction engagement elements that switch a power transmission path of the gear-type transmission mechanism, A control device for an automatic transmission having a hydraulic control circuit that controls the supply and discharge of the operating pressure with respect to the friction engagement elements and switches the gear stage of the gear transmission mechanism, and the input rotational speed of the gear transmission mechanism and An actual gear ratio calculating means for calculating an actual gear ratio based on the output speed, a shift command output means for outputting a shift command according to the operating state, and a target gear specified by the shift command output by the output means Gear failure detection means for detecting a gear failure in which the gear ratio of the gear-type transmission mechanism is not achieved in accordance with the shift command by comparing the gear ratio of the stage with the actual gear ratio, and vehicle speed detection for detecting the vehicle speed A gear-type speed change mechanism is in a neutral state when a gear failure occurs in a predetermined high-speed gear stage, and the shift command output means is operated by the gear failure detection means in the predetermined high-speed gear stage. If the vehicle speed at the time of gear failure detection detected by the vehicle speed detecting means is lower than the predetermined vehicle speed when a failure is detected, the gear shift command has a gear ratio closest to the gear ratio of the predetermined high speed side gear. When the vehicle speed at the time of gear failure detection detected by the vehicle speed detection means is higher than the predetermined vehicle speed, the current shift command is maintained. When the vehicle speed becomes lower than the predetermined vehicle speed, the shift command is changed to a shift command to a predetermined low-speed gear stage.

According to this automatic transmission control device, when it is determined that the automatic transmission is in a neutral state, it is possible to shift to a gear stage that can form the automatic transmission. Thus, by shifting to a gear stage that can form the automatic transmission, the automatic transmission is prevented from being maintained in the neutral state, and the driving force can be transmitted to the drive wheels.
JP-A-11-280898

  By the way, the shift of avoiding the neutral state of Patent Document 1 is a shift from a rotation with a high input shaft rotation speed when the accelerator operation is performed. Therefore, it takes time until the shift is completed and the driving force is transmitted. Further, at this time, the difference in rotational speed of the input shaft relative to the synchronous rotational speed in the gear stage after the shift is large, and it is necessary to reduce the input shaft rotational speed to the synchronous rotational speed by the friction engagement element. For this reason, there is a fear that the thermal durability of the friction engagement element is deteriorated.

  However, Patent Document 1 described above does not mention such problems and solutions.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to realize a quick fail-safe when a desired gear stage is not formed in an automatic transmission and a neutral state is achieved. Another object of the present invention is to provide a shift control device for an automatic transmission that can avoid the thermal durability of a friction engagement element.

  A shift control apparatus for an automatic transmission according to a first invention controls an automatic transmission that forms a plurality of gear stages having different gear ratios by selectively engaging a plurality of friction engagement elements. When it is determined that the automatic transmission is in a neutral state, the control device outputs an avoidance shift command to a gear stage capable of transmitting power, and an avoidance shift command is output. Control means for controlling the shift hydraulic pressure so as to execute the avoidance shift in a control mode in which the control mode of the shift hydraulic pressure control is different from that in the normal mode and the shift time is shorter than the control mode in the normal mode; including.

  According to the first aspect of the invention, when the automatic transmission breaks down and falls into the neutral state, the driving force is not transmitted to the drive wheels, so the avoidance shift is executed in a control mode in which the shift time is shorter than the control mode in the normal state. . For this reason, the time until the driving force is transmitted to the driving wheel can be shortened. In addition, since the sliding time of the friction engagement element to be engaged in the avoidance shift is shortened, deterioration of the thermal durability of the friction engagement element can be suppressed.

  In the shift control device for an automatic transmission according to the second invention, in the first invention, the control mode is such that the start timing of the forced end control for forcibly terminating the shift hydraulic pressure control is earlier than the start timing at the normal time. This is a control mode in which the set value that defines the start timing is made shorter than normal.

  According to the second invention, it is possible to form a gear stage capable of transmitting power quickly without changing the control hydraulic pressure value at the time of shifting (without complicating the hydraulic control logic), and driving force is driven. The time until it is transmitted to the wheel can be shortened.

  In the shift control device for an automatic transmission according to the third invention, in addition to the configuration of the first or second invention, if it is determined that the automatic transmission is in a neutral state during the shift, this shift is performed. Means for setting the setting value for defining the start timing of the forced end control for forcibly terminating the shift hydraulic pressure control to be shorter than the normal time, and ending the shift hydraulic control.

  According to the third aspect of the present invention, if it is determined that the automatic transmission is in a neutral state during a shift, it is possible to terminate the shift at an early stage without complicating the hydraulic control logic. The time until the driving force is transmitted to the driving wheel can be further shortened.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  A vehicle equipped with a control device according to an embodiment of the present invention will be described with reference to FIG. This vehicle is an FF (Front engine Front drive) vehicle. A vehicle other than FF may be used.

  The vehicle includes an engine 1000, an automatic transmission 2000 constituting an automatic transmission, a planetary gear unit 3000 constituting a part of the automatic transmission 2000, a hydraulic circuit 4000 constituting a part of the automatic transmission 2000, and a differential gear 5000. Drive shaft 6000, front wheel 7000, and ECU (Electronic Control Unit) 8000.

  Engine 1000 is an internal combustion engine that burns a mixture of fuel and air injected from an injector (not shown) in a combustion chamber of a cylinder. The piston in the cylinder is pushed down by the combustion, and the crankshaft is rotated.

  The automatic transmission includes an automatic transmission 2000 and a torque converter 3200. Automatic transmission 2000 is connected to engine 1000 via torque converter 3200. Automatic transmission 2000 changes the rotational speed of the crankshaft to a desired rotational speed by forming a desired gear stage.

  The output gear of automatic transmission 2000 is meshed with differential gear 5000. A drive shaft 6000 is connected to the differential gear 5000 by spline fitting or the like. Power is transmitted to the left and right front wheels 7000 via the drive shaft 6000.

  The ECU 8000 includes a vehicle speed sensor 8002, a position switch 8006 of a shift lever 8004, an accelerator opening sensor 8010 of an accelerator pedal 8008, a stroke sensor 8014 of a brake pedal 8012, a throttle opening sensor 8018 of an electronic throttle valve 8016, An engine speed sensor 8020, an input shaft speed sensor 8022, and an output shaft speed sensor 8024 are connected via a harness or the like.

  Vehicle speed sensor 8002 detects the speed of the vehicle from the rotational speed of drive shaft 6000 and transmits a signal representing the detection result to ECU 8000. The position of shift lever 8004 is detected by position switch 8006, and a signal representing the detection result is transmitted to ECU 8000. Corresponding to the position of the shift lever 8004, the gear stage of the automatic transmission 2000 is automatically formed. Further, a manual shift mode in which the driver can select an arbitrary gear stage may be selected according to the driver's operation.

  Accelerator opening sensor 8010 detects the opening of accelerator pedal 8008 and transmits a signal representing the detection result to ECU 8000. Stroke sensor 8014 detects the stroke amount of brake pedal 8012 and transmits a signal representing the detection result to ECU 8000.

  The throttle opening sensor 8018 detects the opening of the electronic throttle valve 8016 whose opening is adjusted by the actuator, and transmits a signal indicating the detection result to the ECU 8000. Electronic throttle valve 8016 adjusts the amount of air taken into engine 1000 (output of engine 1000).

  Engine rotation speed sensor 8020 detects the rotation speed of the output shaft (crankshaft) of engine 1000 and transmits a signal representing the detection result to ECU 8000. Input shaft rotational speed sensor 8022 detects input shaft rotational speed NI of automatic transmission 2000 and transmits a signal representing the detection result to ECU 8000. Output shaft rotation speed sensor 8024 detects output shaft rotation speed NOUT of automatic transmission 2000 and transmits a signal representing the detection result to ECU 8000. The input shaft rotational speed NI of the automatic transmission 2000 is a turbine rotational speed NT of a torque converter 3200 described later.

  ECU 8000 is sent from vehicle speed sensor 8002, position switch 8006, accelerator opening sensor 8010, stroke sensor 8014, throttle opening sensor 8018, engine speed sensor 8020, input shaft speed sensor 8022, output shaft speed sensor 8024, and the like. Based on the received signal, a map and a program stored in a ROM (Read Only Memory), the devices are controlled so that the vehicle is in a desired running state.

  In the present embodiment, ECU 8000 automatically sets any one of the first to sixth gears according to a separately defined shift diagram when shift lever 8004 is in the D (drive) position. The automatic transmission 2000 is controlled to be formed. The automatic transmission 2000 can transmit the driving force to the front wheels 7000 by forming any one of the first to sixth gears.

  In such a case, when the ECU 8000 detects a neutral state due to an abnormality in the solenoid valve, the automatic transmission 2000 is controlled so as to quickly avoid the neutral state.

  The planetary gear unit 3000 will be described with reference to FIG. Planetary gear unit 3000 is connected to a torque converter 3200 having an input shaft 3100 coupled to a crankshaft. Planetary gear unit 3000 includes first set 3300 of planetary gear mechanisms, second set 3400 of planetary gear mechanisms, output gear 3500, B1 brake 3610, B2 brake 3620 and B3 brake 3630 fixed to gear case 3600, and C1. Clutch 3640 and C2 clutch 3650, and one-way clutch F3660 are included.

  The first set 3300 is a single pinion type planetary gear mechanism. First set 3300 includes sun gear S (UD) 3310, pinion gear 3320, ring gear R (UD) 3330, and carrier C (UD) 3340.

  Sun gear S (UD) 3310 is coupled to output shaft 3210 of torque converter 3200. Pinion gear 3320 is rotatably supported by carrier C (UD) 3340. Pinion gear 3320 is in mesh with sun gear S (UD) 3310 and ring gear R (UD) 3330.

  Ring gear R (UD) 3330 is fixed to gear case 3600 by B3 brake 3630. Carrier C (UD) 3340 is fixed to gear case 3600 by B1 brake 3610.

  The second set 3400 is a Ravigneaux type planetary gear mechanism. The second set 3400 includes a sun gear S (D) 3410, a short pinion gear 3420, a carrier C (1) 3422, a long pinion gear 3430, a carrier C (2) 3432, a sun gear S (S) 3440, and a ring gear R. (1) (R (2)) 3450.

  Sun gear S (D) 3410 is coupled to carrier C (UD) 3340. Short pinion gear 3420 is rotatably supported by carrier C (1) 3422. Short pinion gear 3420 is in mesh with sun gear S (D) 3410 and long pinion gear 3430. Carrier C (1) 3422 is coupled to output gear 3500.

  Long pinion gear 3430 is rotatably supported by carrier C (2) 3432. Long pinion gear 3430 is in mesh with short pinion gear 3420, sun gear S (S) 3440, and ring gear R (1) (R (2)) 3450. Carrier C (2) 3432 is coupled to output gear 3500.

  Sun gear S (S) 3440 is coupled to output shaft 3210 of torque converter 3200 by C1 clutch 3640. Ring gear R (1) (R (2)) 3450 is fixed to gear case 3600 by B2 brake 3620 and connected to output shaft 3210 of torque converter 3200 by C2 clutch 3650. The ring gear R (1) (R (2)) 3450 is connected to the one-way clutch F3660, and cannot rotate when the first gear is driven.

  The one-way clutch F3660 is provided in parallel with the B2 brake 3620. That is, the outer race of the one-way clutch F3660 is fixed to the gear case 3600, and the inner race is connected to the ring gear R (1) (R (2)) 3450 via the rotation shaft.

  FIG. 3 shows an operation table showing the relationship between each gear position and the operation state of each clutch and each brake. By operating each brake and each clutch with the combinations shown in this operation table, a forward gear stage of 1st to 6th speed and a reverse gear stage are formed.

  The main part of the hydraulic circuit 4000 will be described with reference to FIG. The hydraulic circuit 4000 is not limited to the one described below.

  The hydraulic circuit 4000 includes an oil pump 4004, a primary regulator valve 4006, a manual valve 4100, a solenoid modulator valve 4200, an SL1 linear solenoid (hereinafter referred to as SL (1)) 4210, and an SL2 linear solenoid (hereinafter referred to as “the solenoid valve”). 4220, SL3 linear solenoid (hereinafter referred to as SL (3)) 4230, SL4 linear solenoid (hereinafter referred to as SL (4)) 4240, and SLT linear solenoid (hereinafter referred to as SL (2)). , SLT) 4300 and a B2 control valve 4500.

  Oil pump 4004 is connected to the crankshaft of engine 1000. As the crankshaft rotates, the oil pump 4004 is driven to generate hydraulic pressure. The hydraulic pressure generated by the oil pump 4004 is regulated by the primary regulator valve 4006 to generate a line pressure.

  Primary regulator valve 4006 operates using the throttle pressure regulated by SLT 4300 as a pilot pressure. The line pressure is supplied to the manual valve 4100 via the line pressure oil passage 4010.

  Manual valve 4100 includes a drain port 4105. From the drain port 4105, the oil pressure in the D range pressure oil passage 4102 and the R range pressure oil passage 4104 is discharged. When the spool of the manual valve 4100 is in the D position, the line pressure oil passage 4010 and the D range pressure oil passage 4102 are communicated, and hydraulic pressure is supplied to the D range pressure oil passage 4102. At this time, the R range pressure oil passage 4104 and the drain port 4105 are communicated, and the R range pressure of the R range pressure oil passage 4104 is discharged from the drain port 4105.

  When the spool of the manual valve 4100 is in the R position, the line pressure oil passage 4010 and the R range pressure oil passage 4104 are communicated, and the oil pressure is supplied to the R range pressure oil passage 4104. At this time, the D range pressure oil passage 4102 and the drain port 4105 are communicated, and the D range pressure in the D range pressure oil passage 4102 is discharged from the drain port 4105.

  When the spool of the manual valve 4100 is in the N position, both the D range pressure oil passage 4102 and the R range pressure oil passage 4104 are connected to the drain port 4105, and the D range pressure and R of the D range pressure oil passage 4102 are communicated. The R range pressure of the range pressure oil passage 4104 is discharged from the drain port 4105.

  The hydraulic pressure supplied to the D range pressure oil passage 4102 is finally supplied to the B1 brake 3610, the B2 brake 3620, the C1 clutch 3640, and the C2 clutch 3650. The hydraulic pressure supplied to the R range pressure oil passage 4104 is finally supplied to the B2 brake 3620.

  The solenoid modulator valve 4200 adjusts the hydraulic pressure (solenoid modulator pressure) supplied to the SLT 4300 to a constant pressure using the line pressure as the original pressure.

  SL (1) 4210 regulates the hydraulic pressure supplied to the C1 clutch 3640. SL (2) 4220 regulates the hydraulic pressure supplied to C2 clutch 3650. SL (3) 4230 regulates the hydraulic pressure supplied to the B1 brake 3610. SL (4) 4240 regulates the hydraulic pressure supplied to the B3 brake 3630.

  The SLT 4300 adjusts the solenoid modulator pressure in accordance with a control signal from the ECU 8000 based on the accelerator opening detected by the accelerator opening sensor 8010, and generates a throttle pressure. The throttle pressure is supplied to the primary regulator valve 4006 via the SLT oil passage 4302. The throttle pressure is used as a pilot pressure for the primary regulator valve 4006.

  SL (1) 4210, SL (2) 4220, SL (3) 4230, SL (4) 4240, and SLT 4300 are controlled by a control signal transmitted from ECU 8000.

  The B2 control valve 4500 selectively supplies the hydraulic pressure from one of the D range pressure oil passage 4102 and the R range pressure oil passage 4104 to the B2 brake 3620. A D range pressure oil passage 4102 and an R range pressure oil passage 4104 are connected to the B2 control valve 4500. The B2 control valve 4500 is controlled by the hydraulic pressure supplied from the SL solenoid valve (not shown) and the SLU solenoid valve (not shown) and the biasing force of the spring.

  When the SL solenoid valve is off and the SLU solenoid valve is on, the B2 control valve 4500 is in the state on the left side in FIG. In this case, the B2 brake 3620 is supplied with the hydraulic pressure adjusted from the D range pressure using the hydraulic pressure supplied from the SLU solenoid valve as a pilot pressure.

  When the SL solenoid valve is on and the SLU solenoid valve is off, the B2 control valve 4500 is in the state on the right side in FIG. In this case, the R range pressure is supplied to the B2 brake 3620.

  With reference to FIG. 3 to FIG. 5, an example of avoidance when the automatic transmission breaks down and enters a neutral state will be described. For example, as shown in FIG. 3A, when the automatic transmission is changed from the 4th speed to the 5th speed, if SL (4) 4240 fails, the hydraulic pressure is not supplied to the B3 brake 3630 and the 5th speed is increased. It cannot be formed and becomes neutral. In such a case, the ECU 8000 engages the B1 brake 3610 using the SL (3) 4230, which is not related to the failure of the SL (4) 4240, and forms the sixth gear that is the avoiding gear stage from the neutral state. .

  Further, as shown in FIG. 3B, when SL (4) 4240 breaks down during traveling at the fifth speed, the hydraulic pressure is not supplied to the B3 brake 3630 and the fifth speed cannot be formed, resulting in a neutral state. In such a case, the ECU 8000 engages the B1 brake 3610 using the SL (3) 4230, which is not related to the failure of the SL (4) 4240, and forms the sixth gear that is the avoiding gear stage from the neutral state. .

  Note that (A) and (B) described above are examples, and the present invention is not limited to such a case. For example, when the automatic transmission is shifted from the 3rd speed to the 4th speed, if the SL (2) 4220 is out of order, the hydraulic pressure is not supplied to the C2 clutch 3650 and the 4th speed cannot be formed, resulting in a neutral state. In such a case, the ECU 8000 may output a shift command so as to return to the third speed, and may be a shift that forms the third speed, which is the avoidance gear stage from the neutral state.

  With reference to FIG. 5, a control structure of a program executed by ECU 8000 which is the control device according to the present embodiment will be described.

  In step (hereinafter, step is abbreviated as S) 100, ECU 8000 determines whether or not the automatic transmission has a neutral failure. For example, during a shift, an electrical failure such as a disconnection or a short circuit is detected based on the value of the current flowing through the solenoid of the solenoid valve to determine a neutral failure. A neutral failure is determined based on the rotational speed NOUT. If it is determined that there is a neutral failure (YES in S100), the process proceeds to S200. If not (NO in S100), the process returns to S100.

  In S200, ECU 8000 determines whether or not a shift is currently being performed. If the speed is currently being changed (YES in S200), the process proceeds to S300. If not (NO in S200), the process proceeds to S600.

  In S300, ECU 8000 shortens the set value of the transmission hydraulic pressure control end timer (sometimes referred to as a backup timer) from the normal time. In S400, ECU 8000 determines whether or not the speed change hydraulic control end timer has expired. When the time is up (YES in S400), the process proceeds to S500. If not (NO in S400), the next process (S500) is not performed until the time is up.

  The transmission hydraulic pressure control end timer is a timer for forcibly ending the transmission hydraulic pressure control when the transmission hydraulic pressure control is continued for a long time because the turbine rotational speed NT is not synchronized with the synchronized rotational speed after shifting. Yes, the count is started when it is detected that the shift is started. When the transmission hydraulic pressure control is not completed and the timer value of the transmission hydraulic control termination timer reaches the set value (when time is up), a command to maximize the hydraulic pressure supplied to the clutch and brake is output to the solenoid valve. So-called forced termination control is executed to forcibly terminate the shift hydraulic pressure control. Therefore, the set value defines the start timing of forced termination control.

  In S500, ECU 8000 executes forced termination control. That is, by executing this control, it is possible to output a shift command to the neutral avoidance gear. In S600, ECU 8000 outputs a shift command to the neutral avoidance gear.

  In S700, ECU 8000 determines whether or not the shift hydraulic pressure control end timer based on the shift command to the neutral avoidance gear stage has expired. That is, it is determined whether it is the start timing of forced termination control. In this case, the set value is also set shorter than the normal value. When the transmission hydraulic pressure control end timer expires (YES in S700), the process proceeds to S800. If not (NO in S700), the next process (S800) is not performed until the time is up.

In S800, ECU 8000 executes forced termination control.
The neutral avoidance operation controlled by ECU 8000 serving as the control apparatus according to the present embodiment based on the above-described structure and flowchart will be described with reference to FIG.

(A) When avoiding neutral to 6th gear while shifting from 4th gear to 5th gear is a case where it is determined that there is a neutral failure (assuming a failure of SL (4) 4240) (YES in S100) ) During the shift from the fourth speed to the fifth speed started at time t (1) in FIG. 6 (YES in S200), the set value of the shift hydraulic pressure control end timer from the fourth speed to the fifth speed is shortened. The That is, if it is originally (no solenoid valve failure), the shift hydraulic pressure control starts counting from the start time t (1) of the shift command from the 4th speed to the 5th speed and time-up at the time t (5). The set value is shortened so that the set value of the end timer expires at time t (2) (S300). Further, if there is no failure of the solenoid valve, the shift from the fourth speed to the fifth speed is completed as indicated by a two-dot chain line indicating normal in FIG.

  At the time t (2), the transmission hydraulic pressure control end timer expires, and the time t (3) (in FIG. 6, the time t (2) and the time t (3) are separated from each other for convenience of explanation. ), A gear shift command to the 6th speed which is the neutral avoiding gear stage is output (S600). This is because the SL (3) 4230 that is not related to the malfunctioning SL (4) 4240 is used to engage the B1 brake 3610 to form the sixth gear to form an avoidance gear stage from the neutral state. .

  When a shift command to the 6th speed, which is the neutral avoidance gear stage, is output and the shift hydraulic pressure control end timer based on this shift command times out, that is, the count starts at time t (3) in FIG. When time is up at t (4) (YES in S700), the neutral avoidance shift is completed (S800). It should be noted that the normal setting value of the transmission hydraulic pressure control end timer from the fifth speed to the sixth speed is set to a time to start counting at time t (5) and time up at time t (6). In the present embodiment, the set time from time t (5) to time t (6) is set short from time t (3) to time t (4).

  Conventionally, as shown by the dotted line in FIG. 6, if SL (4) 4240 is out of order, the hydraulic pressure is not supplied to the B3 brake 3630 and even if the fifth speed cannot be formed, the fourth speed is changed to the fifth speed. The shift command from the 5th speed to the 6th speed is output after the counting is started from the start time t (1) of the shift and time is up at the time t (5). Furthermore, the counting starts from the start time t (5) of the shift from the fifth speed to the sixth speed, and the time is increased at the time t (6), and the shift from the fifth speed to the sixth speed ends. Therefore, the B1 brake 3610 that is engaged using the SL (3) 4230 slips approximately from time t (5) to time t (6) in order to form the sixth gear that is the neutral avoiding gear stage. ing.

  On the other hand, in the present embodiment, the time during which the B1 brake 3610 is slipping is approximately between time t (3) and time t (4). Thus, compared with the prior art, the time during which the B1 brake 3610 is slipping can be shortened, so that the thermal durability of the B1 brake 3610 is not deteriorated.

  Furthermore, the state in which the driving force is not transmitted is conventionally from the time t (1) to the time t (6), but in the present embodiment, the time t (1) to the time t ( 4), the time during which the driving force is not transmitted to the driving wheels can be shortened.

(B) When avoiding neutral at 6th speed during 5th speed When it is determined that a neutral failure has occurred (assuming that SL (4) 4240 is at fault) (YES at S100) and not shifting In this case (NO in S200), the B1 brake 3610 is engaged using SL (3) 4230 not related to the malfunctioning SL (4) 4240 to form the sixth gear to avoid the neutral gear from the neutral state. Form a step. For this purpose, a gear shift command to the neutral avoidance gear is output (time t (3) in FIG. 6).

  When a shift command to the 6th speed, which is the neutral avoidance gear stage, is output and the shift hydraulic pressure control end timer based on this shift command times out, that is, the count starts at time t (3) in FIG. When time is up at t (4) (YES in S700), the neutral avoidance shift is completed (S800). As in the case of (A) described above, the set value of the normal shift oil pressure control end timer from the fifth speed to the sixth speed is a time that starts counting at time t (5) and times up at time t (6). Is set. In the present embodiment, the set time from time t (5) to time t (6) is set short from time t (3) to time t (4).

  As described above, since the shift control from the fifth speed to the sixth speed to the neutral avoidance gear stage is finished early, the time during which the B1 brake 3610 is slipping can be shortened, and the thermal durability of the B1 brake 3610 can be shortened. Does not worsen.

  In S700 of FIG. 5, increasing the hydraulic pressure for shifting more than usual is also an effective method for ending the avoidance shift control to the neutral avoidance gear stage at an early stage. In FIG. 5, the order of S100 and S200 may be reversed, and the neutral failure determination may be performed during the shift (immediately after the start of the shift).

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram which shows the power train controlled by ECU which is a control apparatus which concerns on embodiment of this invention. It is a skeleton figure which shows the gear train in an automatic transmission. It is a figure which shows the operation | movement table | surface of an automatic transmission. It is a figure which shows a part of hydraulic circuit in an automatic transmission. It is a flowchart which shows the control structure of the program which ECU which is a control apparatus which concerns on embodiment of this invention performs. It is a timing chart at the time of neutral avoidance to the 6th speed when the shift command is output from the 4th speed to the 5th speed.

Explanation of symbols

  1000 engine, 2000 automatic transmission, 3000 planetary gear unit, 3100 input shaft, 3200 torque converter, 3210 output shaft, 3610 B1 brake, 3620 B2 brake, 3630 B3 brake, 3640 C1 clutch, 3650 C2 clutch, 3660 one-way clutch F, 4000 hydraulic Circuit, 4004 Oil pump, 4006 Primary regulator valve, 4100 Manual valve, 4200 Solenoid modulator valve, 4210 SL1 linear solenoid, 4220 SL2 linear solenoid, 4230 SL3 linear solenoid, 4240 SL4 linear solenoid, 4300 SLT linear solenoid, 4500 B2 control valve, 8000 E U, 8002 Vehicle speed sensor, 8004 Shift lever, 8006 Position switch, 8008 Accelerator pedal, 8010 Accelerator opening sensor, 8012 Brake pedal, 8014 Stroke sensor, 8016 Electronic throttle valve, 8018 Throttle opening sensor, 8020 Engine speed sensor, 8022 Input shaft speed sensor, 8024 Output shaft speed sensor.

Claims (3)

A shift control device for an automatic transmission that forms a plurality of gear stages having different gear ratios by selectively engaging a plurality of friction engagement elements,
Forced termination control means for forcibly terminating the shift hydraulic control when the duration of the shift hydraulic control executed based on the shift command exceeds a set value;
It means for determining that a failure to become a neutral state in the automatic transmission has occurred,
Command means for outputting an avoidance shift command to a gear stage capable of transmitting power when a failure that causes a neutral state occurs in the automatic transmission ;
A shift control apparatus for an automatic transmission, comprising: a control unit that changes the set value used by the forced termination control unit to be shorter than normal when a failure that causes a neutral state occurs in the automatic transmission. The forced termination control means includes a timer for measuring a time until the duration time reaches the set value when the turbine speed is not synchronized with the post-shift motor speed corresponding to the shift command. A shift control device for an automatic transmission as described. The shift control apparatus for an automatic transmission according to claim 1 or 2, wherein the command means outputs the avoidance shift command after waiting for the forced end of the shift hydraulic pressure control .

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