JP2017067206A - Control device of automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an automatic transmission capable of shortening time lag between engagement of a first frictional engagement element and engagement of a second frictional engagement element in temporarily constituting a prescribed shift stage by engaging the first frictional engagement element and the second frictional engagement element.SOLUTION: When N-D operation for moving a shift lever from a N-position to a D-position is implemented, a brake and a clutch are engaged to temporarily constitute a second speed stage, then the brake is released to execute squat control to constitute a first speed stage. In executing the squat control, a B1 solenoid valve for controlling B1 pressure supplied to the brake is not fully opened, and a necessary transmission pressure capable of securing a transmission torque capacity according to at least an input torque in the brake B1 is supplied to the brake. On the other hand, C2 pressure supplied to the clutch is increased.SELECTED DRAWING: Figure 4

Description

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

  In a vehicle such as an automobile, for example, a driving force from an engine is input to a transmission, and the driving force shifted by the transmission is transmitted to driving wheels. As a transmission, a stepped automatic transmission (AT) is widely known.

  The automatic transmission is provided with a P range (parking range), an R range (reverse range), an N range (neutral range), and a D range (forward range). These ranges are selected by operation (shift operation) of a shift lever disposed in the vehicle interior, and the friction engagement elements provided in the automatic transmission are engaged / released according to the selected range. Is done. Specifically, in the P range and the N range, all the friction engagement elements are released. In the R range, a specific friction engagement element is engaged. In the D range, the friction engagement elements engaged in the R range are released, and a plurality of shift speeds are selectively configured by a combination of engagement and release of the other friction engagement elements. The friction engagement elements are engaged / released by hydraulic pressure.

  When a shift operation (ND operation) instructing switching from the N range to the D range is performed, the friction engagement elements for constituting the first gear are changed from a state in which all the friction engagement elements are released. Hydraulic pressure is supplied and the frictional engagement elements are engaged. When the first gear is configured, the driving force from the engine is decelerated at the gear ratio of the first gear, and torque increased by this deceleration is output from the automatic transmission. As a result, the output torque of the automatic transmission increases abruptly and a shock due to the torque change occurs.

  Therefore, during ND operation, so-called squat control is performed in which the first gear is configured after the second gear is temporarily configured. By this squat control, it is possible to suppress a sudden increase in the output torque of the automatic transmission during the ND operation, and to mitigate the shock that occurs during the ND operation.

Japanese Patent Application Laid-Open No. 2015-117738

  In some automatic transmissions, the second gear is configured by engagement of two friction engagement elements. In the squat control in this automatic transmission, the valve for adjusting the hydraulic pressure supplied to one of the two friction engagement elements for constituting the second gear is fully opened, and the one friction engagement element The maximum hydraulic pressure is supplied to the other, and the hydraulic pressure supplied to the other friction engagement element is gradually increased. Thereby, one friction engagement element engages first, and the other friction engagement element engages after that, and 2nd speed stage is comprised.

  However, when the engine speed is low, such as immediately after starting the engine, the flow rate of oil discharged by the oil pump driven by the engine is small. For this reason, the total amount of oil supplied to the two friction engagement elements may be insufficient, and the engagement of the other friction engagement element may be delayed.

  It is an object of the present invention to engage the first friction engagement element and the second friction engagement element when the first friction engagement element and the second friction engagement element are engaged to temporarily configure a predetermined shift speed. It is an object of the present invention to provide a control device for an automatic transmission that can shorten a time lag with engagement of an engagement element.

  In order to achieve the above object, a control device for an automatic transmission according to the present invention includes a hydraulic circuit to which a hydraulic pressure generated by an oil pump driven by an engine is supplied, and a plurality of units engaged by hydraulic pressure supplied from the hydraulic circuit. A control device for an automatic transmission that includes a friction engagement element and that is configured to selectively have a plurality of shift speeds by a combination of engagement and release of a plurality of friction engagement elements. The first friction engagement element and the second friction engagement element in the released state among the friction engagement elements of the first and second friction engagement elements are engaged to temporarily configure a predetermined shift speed, and then the lower speed side than the predetermined shift speed In order to control the hydraulic pressure supplied to the first friction engagement element, at least the automatic transmission to the automatic transmission is performed without performing the full opening of the valve provided in the hydraulic circuit to control the hydraulic pressure supplied to the first friction engagement element. Transfer torque according to input torque The hydraulic pressure that is ensured in the first friction engagement element is supplied from the hydraulic circuit to the first friction engagement element, and the hydraulic pressure supplied from the hydraulic circuit to the second friction engagement element is increased in parallel with the supply. Let

  According to this configuration, after the first gear engagement element and the second friction engagement element of the plurality of friction engagement elements are engaged to temporarily configure the predetermined shift speed, the predetermined shift speed is Also, the shift control that constitutes the low speed side gear stage is executed. When this shift control is executed, the valve for controlling the hydraulic pressure supplied to the first friction engagement element is not fully opened, and the first friction engagement element has at least a transmission torque capacity corresponding to the input torque. A hydraulic pressure that can be secured is supplied to the first friction engagement element. On the other hand, the hydraulic pressure supplied to the second friction engagement element is increased. Since the hydraulic pressure is not fully supplied to the first friction engagement element and the hydraulic pressure supplied to the first friction engagement element is suppressed, the suppressed hydraulic pressure can be supplied to the second friction engagement element. become. As a result, the slow engagement of the second friction engagement element can be suppressed, and the time lag between the engagement of the first friction engagement element and the engagement of the second friction engagement element can be shortened.

  The shift control may be executed when switching from the neutral range to the forward range of the automatic transmission.

  In this case, it is possible to suppress the occurrence of shock at the time of switching from the neutral range to the forward range of the automatic transmission, and it is possible to quickly shift from a predetermined shift speed to a low speed shift speed. As a result, it is possible to improve the starting performance of a vehicle equipped with an automatic transmission.

  Further, the control device is mounted on a vehicle in which idling stop control for stopping the engine in response to the establishment of a predetermined engine stop condition is executed, and the first friction engagement element and the engine are stopped when the engine is stopped. When the second friction engagement element is released, the shift control may be executed when the engine is restarted.

  In this case, it is possible to suppress the occurrence of a shock when the engine is restarted, and it is possible to quickly shift from a predetermined shift speed to a low speed shift speed. As a result, the start performance of the vehicle when the engine is restarted can be improved.

  According to the present invention, when the first friction engagement element and the second friction engagement element are engaged to form a predetermined shift speed temporarily, the engagement of the second friction engagement element is delayed. And the time lag between the engagement of the first friction engagement element and the engagement of the second friction engagement element can be shortened.

It is a figure which shows the structure of the principal part of the vehicle by which the control apparatus which concerns on one Embodiment of this invention is mounted. It is a skeleton figure which shows the structure of the drive system of a vehicle. It is a figure which shows the state of the engagement element with which the automatic transmission was equipped. It is a figure which shows the time change of the engine speed at the time of a squat control, a turbine speed, B1 pressure, and C2 pressure.

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

<Vehicle configuration>
FIG. 1 is a diagram illustrating a configuration of a main part of a vehicle 1 on which a control device according to an embodiment of the present invention is mounted.

  The vehicle 1 is an automobile that uses the engine 2 as a drive source.

  The output of the engine 2 is transmitted to driving wheels (for example, left and right front wheels) of the vehicle 1 via the torque converter 3 and the automatic transmission 4. The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) that injects fuel into the intake air, and an ignition plug that generates electric discharge in the combustion chamber. It has been. The engine 2 is also provided with a starter for starting the engine 2. The automatic transmission 4 is a stepped automatic transmission.

  The vehicle 1 includes a plurality of ECUs (Electronic Control Units) having a configuration including a CPU, a ROM, a RAM, and the like. The ECU includes an engine ECU 11, an ATECU 12, a brake ECU 13, and an IDS (idling stop) ECU 14. The plurality of ECUs are connected so as to be capable of bidirectional communication using a CAN (Controller Area Network) communication protocol.

  An accelerator sensor 21 and an engine speed sensor 22 are connected to the engine ECU 11.

  The accelerator sensor 21 inputs a signal corresponding to an operation amount of an accelerator pedal (not shown) to the engine ECU 11. Based on the signal input from the accelerator sensor 21, the engine ECU 11 sets the ratio of the operation amount to the maximum operation amount of the accelerator pedal, that is, 0% when the accelerator pedal is not depressed, and the accelerator pedal is depressed to the maximum. The accelerator opening, which is a percentage with the time as 100%, is calculated.

  The engine speed sensor 22 inputs a pulse signal synchronized with the rotation of the engine 2 (rotation of the crankshaft) to the engine ECU 11. The engine ECU 11 converts the frequency of the pulse signal input from the engine speed sensor 22 into the speed of the engine 2 (engine speed).

  The engine ECU 11 is an electronic device provided in the engine 2 for starting, stopping and adjusting the output of the engine 2 based on numerical values obtained from signals inputted from various sensors and various information inputted from other ECUs. Control throttle valves, injectors and spark plugs.

  A shift position sensor 23, a turbine speed sensor 24, and the like are connected to the ATECU 12.

  The shift position sensor 23 inputs a signal corresponding to the position of the shift lever (select lever) to the ATECU 12. As positions of the shift lever, for example, a P position, an R position, an N position, and a D position are provided. The P position, the R position, the N position, and the D position correspond to the P range (parking range), R range (reverse range), N range (neutral range), and D range (forward range), respectively. The shift lever can be shifted between the P position, the R position, the N position, and the D position, and the shift range can be instructed by the shift operation.

  The turbine speed sensor 24 inputs a pulse signal synchronized with the rotation of the turbine runner of the torque converter 3 to the ATECU 12. The ATECU 12 converts the frequency of the pulse signal input from the turbine rotation speed sensor 24 into a turbine rotation speed that is the rotation speed of the turbine runner.

  The ATECU 12 is based on numerical values obtained from signals inputted from various sensors and various information inputted from other ECUs, etc., and the vehicle running state (speed stage, throttle opening, vehicle speed, turbine speed, shift position). In order to change the gear position of the automatic transmission 4 to the target gear position, the valves included in the hydraulic circuit 25 for supplying hydraulic pressure to each part of the automatic transmission 4 are controlled. To do.

  A brake sensor 26 and a vehicle speed sensor 27 are connected to the brake ECU 13.

  The brake sensor 26 outputs a signal corresponding to the amount of operation of the brake pedal disposed in the vehicle interior, and the brake ECU 13 acquires the amount of operation of the brake pedal based on the signal input from the brake sensor 26. .

  The vehicle speed sensor 27 includes, for example, a rotor made of a magnetic material that rotates as the vehicle 1 travels, and an electromagnetic pickup provided in non-contact with the rotor. Each time the rotor rotates by a certain angle, a pulse signal is output from the electromagnetic pickup, and the pulse signal is input to the brake ECU 13. Since the frequency of the pulse signal corresponds to the vehicle speed, the brake ECU 13 can obtain the frequency of the pulse signal input from the vehicle speed sensor 27 by converting it to the vehicle speed.

  The brake ECU 13 controls the brake actuator 28 and the like based on the amount of operation of the brake pedal, the vehicle speed of the vehicle 1, various information input from other ECUs, etc., and the vehicle 1 is kept in a stable posture. The braking force applied to each wheel from each brake is controlled so that the vehicle 1 is braked.

  The vehicle 1 has an idling stop function. The IDSECU 14 performs idling stop control that is control for the idling stop function. As information necessary for the idling stop control, information such as the vehicle speed and the operation amount of the brake pedal is input to the IDSECU 14 from the brake ECU 13.

  In the idling stop control, when the brake pedal is operated (depressed) while the vehicle 1 is traveling, the IDSECU 14 repeatedly determines whether or not a predetermined engine stop condition is satisfied. The engine stop condition is, for example, a condition that the vehicle speed is a predetermined idling stop execution vehicle speed (for example, 10 km / h) or less and the brake pedal is operated for a certain time or more. When the engine stop condition is satisfied, an IDS request is output from the IDSECU 14 to the engine ECU 11, and the engine 2 is automatically stopped by the engine ECU 11.

  While the engine 2 is automatically stopped by the idling stop control, it is repeatedly determined whether or not a predetermined engine restart condition is satisfied. The engine restart condition is, for example, a condition that the operation of the brake pedal is released (the driver's foot is released from the brake pedal) while the engine 2 is automatically stopped. When the restart condition is satisfied, the IDSECU 14 outputs a restart request to the engine ECU 11, and the engine ECU 11 restarts the engine 2.

<Configuration of drive system>
FIG. 2 is a skeleton diagram showing the configuration of the drive system of the vehicle 1.

  The torque converter 3 includes a pump impeller 31, a turbine runner 32, and a lockup clutch 33. An output shaft (E / G output shaft) of the engine 2 is connected to the pump impeller 31, and the pump impeller 31 is provided so as to be integrally rotatable around the same rotation axis as the E / G output shaft. ing. The turbine runner 32 is provided to be rotatable about the same rotation axis as the pump impeller 31. The lockup clutch 33 is provided to directly connect / separate the pump impeller 31 and the turbine runner 32. When the lockup clutch 33 is engaged, the pump impeller 31 and the turbine runner 32 are directly connected, and when the lockup clutch 33 is released, the pump impeller 31 and the turbine runner 32 are separated.

  When the E / G output shaft is rotated in a state where the lockup clutch 33 is released, the pump impeller 31 rotates. When the pump impeller 31 rotates, an oil flow from the pump impeller 31 toward the turbine runner 32 is generated. This oil flow is received by the turbine runner 32 and the turbine runner 32 rotates. At this time, the amplifying action of the torque converter 3 occurs, and the turbine runner 32 generates a power larger than the power (torque) of the E / G output shaft.

  When the lockup clutch 33 is engaged, when the E / G output shaft is rotated, the E / G output shaft, the pump impeller 31 and the turbine runner 32 are rotated together.

  An oil pump 5 is provided between the torque converter 3 and the automatic transmission 4. The pump shaft of the oil pump 5 is provided so as to be rotatable integrally with the pump impeller 31. Thereby, when the pump impeller 31 is rotated by the power of the engine 2, the pump shaft of the oil pump 5 rotates and the oil pump 5 generates hydraulic pressure. The hydraulic pressure generated by the oil pump 5 is supplied to the hydraulic circuit 25.

  The automatic transmission 4 is a four-speed AT having a shift speed of 4 forward speeds and 1 reverse speed. The automatic transmission 4 includes an input shaft 41, an output shaft 42, a center shaft 43, and a Ravigneaux type planetary gear mechanism 44.

  The input shaft 41 is connected to the turbine runner 32 of the torque converter 3 and is provided so as to be integrally rotatable about the same rotation axis as the turbine runner 32.

  The output shaft 42 is provided in parallel with the input shaft 41.

  The center shaft 43 is separated from the input shaft 41 on the side opposite to the engine 2 side, and is provided on the same rotational axis as the input shaft 41.

  The planetary gear mechanism 44 includes a front sun gear 51, a rear sun gear 52, a carrier 53, a ring gear 54, a long pinion gear 55, and a short pinion gear 56. The front sun gear 51 is fitted on the center shaft 43 so as to be relatively rotatable. The rear sun gear 52 is provided on the side opposite to the engine 2 side with respect to the front sun gear 51 and is externally fitted to the center shaft 43 so as to be relatively rotatable. A center shaft 43 is connected to the carrier 53, and the carrier 53 is provided so as to be rotatable integrally with the center shaft 43. The carrier 53 rotatably supports the long pinion gear 55 and the short pinion gear 56. The ring gear 54 has an annular shape that surrounds the periphery of the carrier 53 outside the rear sun gear 52 in the rotational radial direction, and meshes with the long pinion gear 55. The long pinion gear 55 has an axial length longer than that of the short pinion gear 56, and meshes with the front sun gear 51. Short pinion gear 56 meshes with rear sun gear 52 and long pinion gear 55.

  The ring gear 54 holds the first output gear 61 so as to have a common rotation axis. The first output gear 61 is engaged with a second output gear 62 that is supported on the output shaft 42 so as not to rotate relative to the output shaft 42. A third output gear 63 is supported on the output shaft 42 so as not to rotate relative to the output shaft 42, and the third output gear 63 meshes with a ring gear 64 provided in the differential gear 6. Thereby, the rotation of the ring gear 54 is transmitted to the differential gear 6 via the first output gear 61, the second output gear 62, the output shaft 42 and the third output gear 63.

  The automatic transmission 4 includes three clutches C1 to C3, two brakes B1 and B2, and a one-way clutch F.

  The clutch C1 is switched between an engaged state (ON) for connecting the input shaft 41 and the front sun gear 51 and a released state (OFF) for releasing the connection.

  The clutch C2 is switched between an engaged state (ON) for connecting the input shaft 41 and the rear sun gear 52 and a released state (OFF) for releasing the connection.

  The clutch C3 is switched between an engaged state (on) for connecting the input shaft 41 and the center shaft 43 (carrier 53) and a released state (off) for releasing the connection.

  The brake B <b> 1 is switched between an engaged state (on) in which the front sun gear 51 is braked and a released state (off) in which the front sun gear 51 is allowed to rotate.

  The brake B <b> 2 is switched between an engaged state (on) for braking the carrier 53 and a released state (off) allowing the carrier 53 to rotate.

  The one-way clutch F allows only forward rotation of the carrier 53 (rotation in the same direction as the engine output shaft).

  FIG. 3 is a diagram illustrating states of the clutches C1 to C3, the brakes B1 and B2, and the one-way clutch F in the P range, the R range, the N range, and the D range.

  In FIG. 3, “◯” indicates that the clutches C1 to C3 and the brakes B1 and B2 are engaged. In addition, the one-way clutch F is in an engaged state that prevents the carrier 53 from rotating in the reverse direction.

  In the P range and the N range, the clutches C1 to C3 and the brakes B1 and B2 are released.

  In the R range (reverse), the clutch C1 and the brake B2 are engaged, and the clutches C2 and C3 and the brake B1 are released.

  At the first speed in the D range, the clutch C2 is engaged, and the clutches C1, C3 and the brakes B1, B2 are released.

  In the second speed in the D range, the clutch C2 and the brake B1 are engaged, and the clutches C1, C3 and the brake B2 are released.

  In the third speed of the D range, the clutches C2 and C3 are engaged, and the clutch C1 and the brakes B1 and B2 are released.

  At the fourth speed in the D range, the clutch C3 and the brake B1 are engaged, and the clutches C1, C2 and the brake B2 are released.

<Square control>
FIG. 4 is a diagram showing temporal changes in engine speed, turbine speed, B1 pressure (hydraulic pressure supplied to the brake B1) and C2 pressure (hydraulic pressure supplied to the clutch C2) during squat control.

  When a shift operation for instructing switching from the N range to the D range, that is, an ND operation for moving the shift lever from the N position to the D position, the ATECU 12 executes the squat control. In the squat control, after the brake B1 and the clutch C2 are engaged and the second gear is configured, the brake B1 is released while the clutch C2 is engaged and the first gear is configured.

  In this squat control, the hydraulic pressure supplied to the brake B1 and the clutch C2 is controlled as follows.

  In response to the ND operation being performed, the required transmission torque capacity required for the brake B1 is calculated with respect to the input torque to the automatic transmission 4. This required transmission torque capacity is, for example, a transmission torque capacity at which the brake B1 does not slip with respect to the input torque to the automatic transmission 4. Then, the required transmission pressure, which is a hydraulic pressure that secures the required transmission torque capacity in the brake B1, is acquired, and the hydraulic pressure (B1 pressure) supplied to the brake B1 is controlled so that the required transmission pressure is supplied to the brake B1. The command current value (target value of the current supplied to the B1 solenoid valve 71) of the B1 solenoid valve 71 (see FIG. 1) is set.

  The necessary transmission pressure is supplied to the brake B1 by controlling the current supplied to the B1 solenoid valve 71 based on the command current value set in this way (time T1). This necessary transmission pressure is lower than the maximum pressure supplied to the brake B1 when the B1 solenoid valve 71 is fully opened. Thereafter, the B1 pressure supplied to the brake B1 is held at the necessary transmission pressure.

  While the necessary transmission pressure is supplied to the brake B1, the C2 solenoid valve 72 (see FIG. 1) that controls the hydraulic pressure supplied to the clutch C2 is controlled. That is, the command current value of the C2 solenoid valve 72 (the target value of the current supplied to the C2 solenoid valve 72) is gradually increased. As a result, the hydraulic pressure (C2 pressure) supplied to the clutch C2 increases.

  While the B1 pressure is maintained at the necessary transmission pressure, the turbine speed increases. It is determined whether or not the turbine rotational speed is within a predetermined range including the second-speed synchronous rotational speed (second-speed synchronous rotational speed), and the turbine rotational speed is within the predetermined range. Is determined, the indicated current value of the B1 solenoid valve 71 is lowered, and the B1 pressure is lowered to a predetermined pressure (time T2).

  Thereafter, the indicated current value of the B1 solenoid valve 71 is decreased by a certain time gradient, whereby the B1 pressure gradually decreases (time T2-T3). Then, when it is determined that the turbine rotational speed that has been changed from being lowered to increased is within a predetermined range including the first-speed synchronous rotational speed (first-speed synchronous determination) (time T3), an instruction from the B1 solenoid valve 71 is given. The current value is lowered to 0, and the B1 pressure is lowered to 0.

<Effect>
As described above, when the ND operation for moving the shift lever from the N position to the D position is performed, the brake B1 and the clutch C2 are engaged to temporarily configure the second gear, and then the brake B1 is The squat control that constitutes the first gear stage is executed. When executing the squat control, the B1 solenoid valve 71 for controlling the B1 pressure supplied to the brake B1 is not fully opened, and the brake B1 has at least a transmission torque capacity corresponding to the input torque. Possible necessary transmission pressure is supplied. On the other hand, the C2 pressure supplied to the clutch C2 is increased. Since the B1 pressure is kept lower than the maximum pressure (the B1 pressure when the B1 solenoid valve 71 is fully opened), the time change of the C2 pressure shown by the solid line in FIG. 4 and the C2 pressure by the conventional control shown by the two-dot chain line are shown. As understood from comparison with the time change, the hydraulic pressure corresponding to the suppressed B1 pressure can be supplied to the clutch C2 as the C2 pressure. As a result, the slow engagement of the clutch C2 can be suppressed, and the time lag between the engagement of the brake B1 and the engagement of the clutch C2 can be shortened.

<Modification>
As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form.

  For example, in the above-described embodiment, the squat control at the time of ND operation is taken up. However, the present invention is applied to the squat control when the first gear is configured in response to the restart of the engine 2 by the idling control. May be. Thereby, generation | occurrence | production of the shock at the time of restart of the engine 2 can be suppressed.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

2 Engine 4 Automatic transmission 5 Oil pump 12 ATECU (control device)
25 Hydraulic circuit 71 B1 solenoid valve (valve)
B1 Brake (first friction engagement element)
C2 clutch (second friction engagement element)

Claims (1)

An oil circuit driven by an engine is provided with a hydraulic circuit to which a generated hydraulic pressure is supplied, and a plurality of friction engagement elements engaged by the hydraulic pressure supplied from the hydraulic circuit, and the engagement and release of the plurality of friction engagement elements A control device for an automatic transmission in which a plurality of shift stages are selectively configured by a combination of:
The hydraulic circuit is controlled to engage a first friction engagement element and a second friction engagement element in a released state among the plurality of friction engagement elements to temporarily configure a predetermined gear stage. Thereafter, when executing the shift control that configures the shift stage on the lower speed side than the predetermined shift stage,
Without fully opening a valve provided in the hydraulic circuit to control the hydraulic pressure supplied to the first friction engagement element, at least the transmission torque capacity corresponding to the input torque to the automatic transmission is the first. A hydraulic pressure secured to one friction engagement element is supplied from the hydraulic circuit to the first friction engagement element;
In parallel with the supply, the control device increases the hydraulic pressure supplied from the hydraulic circuit to the second friction engagement element.

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