JP6646482B2 - Vehicle control device and vehicle control method - Google Patents

Description

  The present invention relates to a vehicle control device and a vehicle control method.

  Patent Literature 1 discloses a technique in which when a failure occurs in which a lock-up clutch cannot be released, a transmission clutch of an automatic transmission is released to be in a neutral state. According to this, since the power transmission between the engine and the drive wheels is cut off, occurrence of engine stall when the vehicle stops can be prevented.

JP 2003-287123 A

  However, according to the above-described technology, when a failure occurs in which the lock-up clutch cannot be released while traveling on an uphill road, the vehicle decelerates unless the driver notices that the automatic transmission is in the neutral state. It is conceivable that the vehicle may not only stop but also eventually retreat.

  The present invention has been made in view of such a technical problem, and in the event of a failure in which a lock-up clutch cannot be disengaged, prevents the occurrence of engine stall and prevents the vehicle from retreating on an uphill road. The purpose is to:

According to an embodiment of the present invention, an automatic transmission including an engine, a torque converter having a lock-up clutch, a plurality of fastening elements, and a parking lock mechanism provided downstream of the plurality of fastening elements in a power transmission path. A control device for the vehicle , comprising: when traveling while selecting a forward range, when a failure occurs in which the lock-up clutch cannot be disengaged, the automatic transmission is set to a neutral state, And a control unit for activating the parking lock mechanism when the vehicle speed falls below a predetermined vehicle speed including a stopped vehicle speed.

According to another aspect of the present invention, there is provided an engine, a torque converter having a lock-up clutch, a plurality of fastening elements, and a parking lock mechanism provided downstream of the plurality of fastening elements in a power transmission path. The automatic transmission having the automatic transmission in a neutral state when a failure occurs in which the lock-up clutch cannot be disengaged during traveling while selecting a forward range. Thereafter, when the vehicle speed becomes equal to or lower than a predetermined vehicle speed including a stopped vehicle speed, the parking lock mechanism is operated, and a vehicle control method is provided.

According to these aspects, when a failure occurs in which the lock-up clutch cannot be disengaged while the vehicle is traveling with the forward range selected , the engine stall is prevented from occurring and the vehicle is caused to retreat on the uphill road. Can be prevented.

1 is a schematic configuration diagram of a vehicle to which a control device according to an embodiment of the present invention is applied. 5 is a flowchart showing the contents of stop control executed by the controller. 5 is a time chart showing a state in which stop control is executed. FIG. 3 is a diagram illustrating a control circuit of a lock-up solenoid valve.

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

  FIG. 1 shows a schematic configuration of a vehicle 100 to which a control device according to an embodiment of the present invention is applied.

  The vehicle 100 includes an engine 1, a torque converter 2, and an automatic transmission 3, and the output rotation of the engine 1 is transmitted to drive wheels (not shown) via the torque converter 2 and the automatic transmission 3. It is.

  The torque converter 2 is a torque converter with a lock-up clutch 21. If the lock-up clutch 21 is engaged, the input shaft and the output shaft are directly connected, and transmission loss due to slippage inside the torque converter 2 can be reduced. The lock-up clutch 21 is engaged when the vehicle speed exceeds a lock-up start vehicle speed (for example, 18 km / h), and is released when the vehicle speed falls below a lock-up release vehicle speed (for example, 15 km / h).

  The automatic transmission 3 is a stepped automatic transmission having a plurality of forward gears and one reverse gear. The gear position can be changed depending on what combination of the plurality of fastening elements 32 (clutch, brake) arranged inside the automatic transmission 3 is engaged. Further, the automatic transmission 3 has a parking lock mechanism 31 provided downstream of the plurality of fastening elements 32 in the power transmission path.

  The park lock mechanism 31 is a braking device that locks the output shaft 33 when the parking range is selected as the shift range. The park lock mechanism 31 of the present embodiment is a park-by-wire system that can electrically control an operation state (park lock on) and a non-operation state (park lock off).

  Further, the vehicle 100 has a hydraulic control circuit 4 that regulates the pressure of hydraulic oil supplied from an oil pump (not shown) and supplies the pressure to the lock-up clutch 21 and each part of the automatic transmission 3, And a controller 5 for controlling the circuit 4 and the like.

  The hydraulic control circuit 4 controls a plurality of solenoid valves including a lock-up solenoid valve 40 as an actuator for controlling the lock-up clutch 21 based on a control signal from the controller 5 to switch a hydraulic pressure supply path and to control a hydraulic supply path. The pressure of the supplied hydraulic oil is adjusted to generate a required hydraulic pressure, which is supplied to the lock-up clutch 21 and each part of the automatic transmission 3.

  The controller 5 is configured to include a CPU, a ROM, a RAM, an input / output interface, a bus connecting them, and the like, and based on a signal from a sensor that detects a state of each part of the vehicle 100, a rotation speed and a torque of the engine 1 and a lock. The engaged state of the up-clutch 21, the gear position of the automatic transmission 3, the state of the parking lock mechanism 31, the display contents of the indicator 47, and the like are integrally controlled.

  The sensors include, for example, a rotation speed sensor 41 that detects the rotation speed Ne of the engine 1, a rotation speed sensor 42 that detects the rotation speed Nt of the output shaft of the torque converter 2, and a rotation speed Ns of the output shaft 33 of the automatic transmission 3. , An accelerator opening sensor 44 for detecting the operation state of the accelerator pedal 6, a brake switch 45 for detecting the operation state of the brake pedal 7, and a shifter 8 for P (parking), R (reverse), N A position sensor 46 for detecting which of the (neutral) and D (forward) ranges has been selected is included. The range can be determined by a combination of a plurality of switches instead of the position sensor 46.

  The shifter 8 of this embodiment is a momentary shift lever that automatically returns to the initial position when the driver releases his hand after selecting the shift range. Note that the shifter 8 is not limited to the lever type, and may be, for example, a switch type.

  In addition, the controller 5 detects the presence or absence of an abnormality in each part of the vehicle 100 based on the signal from each of the sensors, and when a failure occurs, performs control according to the content thereof. I have.

  Hereinafter, the stop control performed by the controller 5 when a failure occurs in which the lock-up clutch 21 cannot be released will be described with reference to the flowchart shown in FIG.

  Until step S14 in FIG. 2, an abnormality detection process for detecting whether or not a failure has occurred in which the lock-up clutch 21 cannot be disengaged. From step S15, the controller 5 determines whether the failure has occurred. Shows the stop control executed by. The abnormality detection processing is executed when the vehicle speed falls below the lockup release vehicle speed.

  In step S11, the controller 5 determines whether the command pressure to the lock-up solenoid valve 40 is smaller than a threshold value.

  The lock-up clutch 21 is engaged when the command pressure to the lock-up solenoid valve 40 is large and the control current of the lock-up solenoid valve 40 increases. Conversely, when the command pressure to the lock-up solenoid valve 40 decreases and the control current of the lock-up solenoid valve 40 decreases, the lock-up solenoid valve 40 is released.

  Therefore, the fact that the command pressure to the lock-up solenoid valve 40 is smaller than the threshold value means that the controller 5 has instructed the release of the lock-up clutch 21.

  If the controller 5 determines that the command pressure to the lock-up solenoid valve 40 is smaller than the threshold, the process proceeds to step S12. Further, when it is determined that the command pressure to the lock-up solenoid valve 40 is equal to or higher than the threshold, the process of step S11 is repeated.

  In step S12, the controller 5 determines whether the absolute value of the difference between the rotation speed Ne of the engine 1 and the rotation speed Nt of the torque converter 2 is equal to or smaller than a threshold.

  When the absolute value of the difference between the rotation speed Ne and the rotation speed Nt is equal to or smaller than the threshold value, it means that the slip inside the torque converter 2 has not occurred. In this case, there is a possibility that the lock-up clutch 21 is engaged even though the controller 5 instructs the release of the lock-up clutch 21.

  When the controller 5 determines that the absolute value of the difference between the rotation speed Ne and the rotation speed Nt is equal to or smaller than the threshold, the process proceeds to step S13. If it is determined that the absolute value of the difference between the rotation speed Ne and the rotation speed Nt is larger than the threshold, the process returns to step S11 to repeat the processing.

  In step S13, the controller 5 determines whether the state where the absolute value of the difference between the rotation speed Ne and the rotation speed Nt is equal to or less than the threshold has continued for a predetermined time.

  Depending on the traveling state of the vehicle 100, the absolute value of the difference between the rotation speed Ne and the rotation speed Nt may temporarily be lower than or equal to the threshold. Therefore, when the state where the absolute value of the difference between the rotation speed Ne and the rotation speed Nt is equal to or less than the threshold value continues for a predetermined time, the controller 5 determines that a failure has occurred in which the lockup clutch 21 cannot be released (step S14). . The predetermined time is, for example, 1 second. If the state in which the absolute value of the difference between the rotation speed Ne and the rotation speed Nt is equal to or smaller than the threshold has not continued for a predetermined time, the process returns to step S11 to repeat the processing.

  In step S14, the controller 5 issues a warning to notify the driver that a failure has occurred. There are various warnings, such as generating a warning sound using a speaker or the like of the vehicle 100 or turning on a warning light provided on the indicator 47 of the vehicle 100. As a result, the driver can be made aware that a failure has occurred, and the brake operation can be encouraged.

  Subsequently, in step S15, the controller 5 determines whether the vehicle speed has become equal to or less than the first vehicle speed.

  The first vehicle speed is a vehicle speed at which an engine stall may occur if the vehicle speed further decreases, and is, for example, 10 km / h.

  When determining that the vehicle speed is equal to or lower than the first vehicle speed, the controller 5 shifts the processing to step S16. If it is determined that the vehicle speed is higher than the first vehicle speed, the process of step S15 is repeated.

  In step S16, the controller 5 performs neutral control for automatically setting the automatic transmission 3 to the neutral state.

  Specifically, regardless of the currently selected shift range, the controller 5 releases the fastening element 32 to put the automatic transmission 3 in the neutral state, and transmits power between the engine 1 and the torque converter 2 and the drive wheels. Disconnect. The indicator 47 displays the letter "N" as information indicating that the neutral range is set.

  The information displayed on the indicator 47 may be any information as long as the driver can be informed that the vehicle is in the neutral range, and is not limited to the letter “N”. At this time, the parking lock mechanism 31 is in a non-operating state (park lock off).

  At the time when the neutral control is performed, the driver normally selects the D range as the shift range. Here, assuming that the shifter 8 is a link-type shift lever generally used conventionally, the indicator 47 indicates that the automatic transmission 3 is in the D range even if the automatic transmission 3 is actually in the neutral state. “D” is displayed. Since the driver determines the currently selected shift range mainly based on the position of the shift lever and the display of the indicator 47, the driver is likely to determine that the vehicle is traveling in the D range.

  On the other hand, in the present embodiment, as described above, a momentary shift lever is used as the shifter 8. Therefore, the criterion for determining the shift range of the driver can be only the display of the indicator 47, and by displaying "N" on the indicator 47 after the occurrence of a failure, the driver can recognize that the vehicle is in the neutral range, Brake operation can be prompted.

  In step S17, the controller 5 determines whether the vehicle speed has become equal to or lower than the second vehicle speed as the predetermined vehicle speed.

  The second vehicle speed is a vehicle speed immediately before the vehicle 100 stops, and is, for example, 2 km / h. Note that the second vehicle speed includes a stop speed (0 km / h). Therefore, the second vehicle speed can be selected from vehicle speeds equal to or lower than an arbitrary vehicle speed (low vehicle speed) including the stop speed.

  When determining that the vehicle speed is equal to or lower than the second vehicle speed, the controller 5 shifts the processing to step S18. If it is determined that the vehicle speed is higher than the second vehicle speed, the process of step S17 is repeated.

  In step S18, the controller 5 performs park control for automatically operating the parking lock mechanism 31 of the automatic transmission 3.

  Specifically, the controller 5 operates the parking lock mechanism 31 of the automatic transmission 3 while keeping the automatic transmission 3 in the neutral state, locks the output shaft 33, and stops the vehicle 100 (park lock on). In addition, an alphabet “P” is displayed on the indicator 47 as information indicating that the vehicle is in the parking range. The information displayed on the indicator 47 is not limited to the letter "P" as long as it can inform the driver that the parking range is set.

  As described above, in the present embodiment, the momentary shift lever is used as the shifter 8. Therefore, at the time when the park control is executed, similarly to the time when the neutral control is executed, the criterion for determining the shift range of the driver is used. Can be displayed only on the indicator 47, and by displaying “P” on the indicator 47 after the occurrence of a failure, the driver can recognize that the vehicle is in the parking range, and the brake operation can be prompted.

  As described above, when a failure occurs in which the lock-up clutch 21 cannot be released, the controller 5 performs the neutral control that automatically sets the automatic transmission 3 to the neutral state when the vehicle speed becomes equal to or less than the first vehicle speed, Thereafter, when the vehicle speed becomes equal to or lower than the second vehicle speed, park control for automatically operating the parking lock mechanism 31 is performed.

  According to this, by causing the automatic transmission 3 to be in the neutral state, it is possible to prevent engine stall from occurring when the vehicle 100 stops. Further, since the parking lock mechanism 31 is operated when the vehicle 100 stops, even if a failure occurs in which the lock-up clutch 21 cannot be disengaged while traveling on an uphill road, the vehicle 100 can be prevented from retreating.

  Subsequently, the manner in which the stop control is executed will be described with reference to the time chart of FIG.

  If the vehicle speed (rotational speed Ns) decreases in a state where a failure occurs in which the lock-up clutch 21 cannot be released, the lock-up clutch 21 is engaged even after the vehicle speed becomes the lock-up release vehicle speed at time t1. Will remain. Therefore, even after time t1, the rotation speed Ne of the engine 1 and the rotation speed Nt of the torque converter 2 decrease in proportion to the decrease in the rotation speed Ns.

  When the vehicle speed becomes the first vehicle speed at time t2, the neutral control is executed, and the automatic transmission 3 enters the neutral state. Thereby, power transmission between the engine 1 and the torque converter 2 and the drive wheels is cut off. Therefore, after the time t2, the decrease in the rotation speed Ne and the rotation speed Nt is not proportional to the decrease in the rotation speed Ns.

  The rotation speed Ne and the rotation speed Nt gradually decrease from time t2 to time t3, and reach the idle rotation speed of the engine 1. Note that the dotted lines shown after time t2 indicate changes in the rotation speed Ne and the rotation speed Nt when the neutral control is not performed. In this case, the engine stall occurs shortly after the time t3, and the rotation speed Ne and the rotation speed Nt become zero.

  When the vehicle speed becomes the second vehicle speed at time t4, the park control is executed, the parking lock is turned on, and the vehicle 100 stops.

  As described above, the controller 5 of the present embodiment sets the automatic transmission 3 to the neutral state when a failure occurs in which the lock-up clutch 21 cannot be released, and then sets the parking lock mechanism 31 when the vehicle speed falls below the second vehicle speed. Activate

  According to this, it is possible to prevent engine stall from occurring and to prevent the vehicle 100 from moving backward on an uphill road (an effect corresponding to claims 1 and 6).

  The vehicle 100 also includes a shifter 8 that returns to the initial position after the driver selects a shift range. When the controller 5 sets the automatic transmission 3 to the neutral state after the occurrence of a failure, the indicator 47 displays the neutral state of the automatic transmission 3. “N” is displayed as information indicating that the range is set.

  According to this, the criterion of the driver's shift range can be determined only by displaying the indicator 47, and by displaying "N" on the indicator 47 after the occurrence of a failure, the driver is notified that the vehicle is in the neutral range. Recognition can be performed, and a brake operation can be prompted (effect corresponding to claim 2).

  Further, when the controller 5 operates the parking lock mechanism 31 after the occurrence of the failure, the controller 47 causes the indicator 47 to display “P” as information indicating that the automatic transmission 3 is in the parking range.

  According to this, it is possible to make the driver recognize that the vehicle is in the parking range and to urge the brake operation (an effect corresponding to claim 3).

  Also. The controller 5 generates a warning sound or turns on a warning lamp after a failure occurs.

  According to this, it is possible to make the driver recognize that a failure has occurred, and to urge the brake operation (an effect corresponding to claim 4).

  As described above, the embodiments of the present invention have been described. However, the above embodiments are merely examples of the application of the present invention, and the technical scope of the present invention is limited to the specific configurations of the above embodiments. is not.

  For example, in the above embodiment, when a failure occurs in which the lock-up clutch 21 cannot be released, the controller 5 executes the stop control. Here, the causes of the failure in which the lock-up clutch 21 cannot be released include electrical abnormalities such as short-to-power, functional abnormalities (mechanical abnormalities) such as particles clogging the lock-up solenoid valve 40, and the like. There is. Therefore, when a failure occurs due to an electrical abnormality of the lock-up solenoid valve 40, the lock-up solenoid valve 40 may be forcibly turned off to release the lock-up clutch 21.

  In order to forcibly turn off the lock-up solenoid valve 40 in which the electrical abnormality has occurred, as shown in the control circuit of FIG. 4, the drivers 50 and 51 are provided upstream and downstream of the lock-up solenoid valve 40, respectively. Should be provided.

  In this configuration, when a failure occurs, the lock-up solenoid valve 40 can be completely disconnected from the circuit by opening the drivers 50 and 51. Therefore, for example, even when a short-to-supply fault occurs, the lock-up solenoid valve 40 can be forcibly turned off.

  In other words, in the case of an electrical abnormality, the lock-up solenoid valve 40 is forcibly turned off, while in the case of a functional abnormality, the automatic transmission 3 is set in the neutral state. The mechanism 31 can be operated.

  According to this, the degree of freedom in responding to a failure in which the lock-up clutch 21 cannot be released is improved (an effect corresponding to claim 5).

100 vehicle 1 engine 2 torque converter 3 automatic transmission 5 controller (control device, control unit)
8 Shifter 21 Lock-up clutch 31 Park lock mechanism 32 Fastening element 40 Lock-up solenoid valve (actuator)
47 Indicator

Claims (6)

Control of a vehicle including an engine, a torque converter having a lock-up clutch, and an automatic transmission having a plurality of fastening elements and a parking lock mechanism provided downstream of the plurality of fastening elements in a power transmission path. A device,
If a failure occurs in which the lock-up clutch cannot be disengaged while the vehicle is traveling with the forward range selected, the automatic transmission is set to the neutral state. Including a control unit for operating the lock mechanism,
A control device for a vehicle, comprising: The vehicle control device according to claim 1,
The vehicle further includes a shifter that returns to an initial position after a driver selects a shift range,
When the automatic transmission is in the neutral state after the occurrence of the failure, the control unit displays information indicating that the automatic transmission is in the neutral range on the indicator of the vehicle,
A control device for a vehicle, comprising: The vehicle control device according to claim 2, wherein
The control unit, when operating the park lock mechanism after the occurrence of the failure, causes the indicator to display information indicating that the automatic transmission is in a parking range,
A control device for a vehicle, comprising: The vehicle control device according to claim 2 or 3,
The control unit generates a warning sound or turns on a warning light after the occurrence of the failure,
A control device for a vehicle, comprising: The vehicle control device according to any one of claims 1 to 4,
The control unit, when the failure occurs due to an electrical abnormality of an actuator that controls the lock-up clutch, forcibly turns off the actuator to release the lock-up clutch,
A control device for a vehicle, comprising: Control of a vehicle including an engine, a torque converter having a lock-up clutch, and an automatic transmission having a plurality of fastening elements and a parking lock mechanism provided downstream of the plurality of fastening elements in a power transmission path. The method
If a failure occurs in which the lock-up clutch cannot be disengaged while the vehicle is traveling with the forward range selected, the automatic transmission is set to the neutral state. Activate the lock mechanism,
A method for controlling a vehicle, comprising:

Images