JP6692572B2 - Automatic transmission control device - Google Patents

Description

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

  In recent years, so-called idling stop control has been widely adopted for vehicles using an engine as a drive source for the purpose of improving fuel efficiency. In the idling stop control, for example, when the brake pedal is depressed by the driver's foot to operate the brake and the vehicle speed drops below a predetermined idling stop execution vehicle speed, the engine is automatically stopped (idling stop). After the engine is automatically stopped, for example, when the foot is released from the brake pedal and the brake is released, the engine is automatically restarted (restored from idling stop).

  Some vehicles that employ idling stop control are equipped with a stepped automatic transmission (AT) as a transmission. 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 operating a shift lever provided in the vehicle compartment, and a clutch (brake) provided in the automatic transmission is engaged / released according to the selected range. Specifically, all clutches are released in the P range and the N range. In the R range, a specific clutch is engaged. In the D range, the clutch engaged in the R range is released, and a combination of engagement and release of the other clutches selectively configures a plurality of shift speeds. The clutch is hydraulically engaged / disengaged.

  FIG. 10 is a diagram showing an example of a change over time in the command hydraulic pressure of the clutch, the engine speed, the turbine speed, and the acceleration generated in the vehicle at the time of returning from the idling stop.

  Since the mechanical oil pump driven by the power of the engine is stopped during idling stop, the hydraulic pressure is released from each clutch of the automatic transmission and each clutch is released. Therefore, when returning from the idling stop, the control device that controls the automatic transmission engages the clutch (for example, when the shift lever is located at the D position corresponding to the D range, the clutch forming the first speed). Engagement control is performed.

  That is, when the brake is released, the engine is cranked, and the command hydraulic pressure, which is the target value of the hydraulic pressure supplied to the clutch, is increased to a filling pressure higher than a predetermined initial pressure (time T101).

  While the engine is cranking, the spark plug of the engine is sparked, so that the engine is completely detonated and the cranking is ended. Due to the complete explosion of the engine, the engine speed increases, and the turbine speed, which is the speed of the turbine runner of the torque converter, increases as the engine speed increases.

  When the rotation speed of the engine rises to a predetermined rotation speed (for example, 400 rpm), the control device determines that the engine has completely exploded. From the start of cranking to the determination of complete explosion, the command hydraulic pressure of the clutch is maintained at the filling pressure. By the filling control in which the command hydraulic pressure is maintained at the filling pressure, the filling of the clutch with oil can be accelerated and the responsiveness of the clutch can be improved.

  When it is determined that the engine has completely exploded, the command hydraulic pressure of the clutch is lowered from the filling pressure to the initial pressure (time T102). After that, the command hydraulic pressure of the clutch is maintained at the initial pressure. Meanwhile, the filling of the clutch with oil is completed (time T103). When the filling of the clutch with oil is completed and the piston for bringing the clutch plate and the clutch disc into pressure contact with each other to generate a frictional force comes into contact with the clutch plate, the clutch begins to engage while sliding. Along with this, the torque transmission capacity of the clutch increases and the turbine speed decreases.

  When the turbine speed drops by a predetermined amount (time T104), the command oil pressure of the clutch is gradually increased by the sweep at a constant time change rate.

  When clutch engagement progresses and clutch slippage disappears, the turbine rotation speed stops falling, and turbine rotation speed becomes 1st speed synchronous rotation speed (output rotation of the automatic transmission when 1st speed is configured). Number of revolutions synchronized with the number). When this turbine speed synchronization is detected (time T105), the command hydraulic pressure of the clutch is increased to the maximum pressure, and the engagement control is ended.

JP, 2005-117738, A

  When the clutch starts to be engaged, the vehicle starts moving and the vehicle is accelerated. Further, at the time of synchronization in which the turbine rotation speed matches the first speed synchronous rotation speed, the turbine rotation speed stops decreasing, and therefore the change in turbine rotation speed appears as a change in vehicle acceleration.

  In the conventional engagement control, if the initial pressure that is the command hydraulic pressure of the clutch after the filling control is high, the time lag from the start of engine cranking to the start of the vehicle is short, but the shock due to the change in acceleration during synchronization is large. .. Moreover, a shock may occur when the piston of the clutch contacts the clutch plate. On the other hand, when the initial pressure is low, it is possible to suppress the synchronous shock that occurs at the time of synchronization, but the time lag from the start of engine cranking to the start of movement of the vehicle becomes long. That is, the conventional engagement control cannot achieve both suppression of the synchronous shock and reduction of the time lag.

  An object of the present invention is to provide a control device for an automatic transmission that can achieve both reduction of time lag and suppression of synchronous shock.

  In order to achieve the above object, a control device for an automatic transmission according to the present invention is a control device for an automatic transmission that includes a hydraulic circuit and an engagement element that is engaged by hydraulic pressure supplied from the hydraulic circuit. The hydraulic circuit of the transmission is controlled to execute the engagement control for engaging the engagement element of the automatic transmission, and in the engagement control, the instruction hydraulic pressure that is the target value of the hydraulic pressure supplied to the engagement element is set. The filling process is performed to increase the filling pressure to hold the indicated hydraulic pressure at the filling pressure for a predetermined time, and after the filling process, the indicated hydraulic pressure is reduced to a first initial pressure that is lower than the filling pressure so that the engagement element transmits torque. Until the start of holding, the first initial processing for maintaining the instruction hydraulic pressure at the first initial pressure, and after the first initial processing, the instruction hydraulic pressure is reduced from the first initial pressure to the second initial pressure lower than the first initial pressure. The rotation speed input to the automatic transmission drops by a predetermined amount. During executes a second initialization process that holds the command hydraulic pressure to the second initial pressure, after the second initialization process, and increase process for increasing the command hydraulic pressure from the second initial pressure.

  According to this configuration, in the engagement control for engaging the engagement element of the automatic transmission, the instruction hydraulic pressure is raised to the filling pressure, and the instruction hydraulic pressure is maintained at the filling pressure for a predetermined time. Thereafter, the command hydraulic pressure is reduced from the filling pressure to the first initial pressure, and the command hydraulic pressure is maintained at the first initial pressure until the engagement element starts to have the torque transmission capacity. When the engagement element starts to have the torque transmission capacity, the instruction hydraulic pressure is reduced from the first initial pressure to the second initial pressure, and the instruction is continued until the rotation speed input to the automatic transmission falls from the peak by a predetermined amount. The hydraulic pressure is maintained at the second initial pressure. Then, when the rotational speed input to the automatic transmission falls from the peak by a predetermined amount, the command hydraulic pressure is increased from the second initial pressure.

  In the conventional engagement control, after the command hydraulic pressure is maintained at the filling pressure, the command hydraulic pressure is maintained at a constant initial pressure. On the other hand, in the engagement control according to the present invention, after the instructed oil pressure is maintained at the filling pressure, the instructed oil pressure is reduced to the second initial pressure in two steps after a period in which the instructed oil pressure is maintained at the first initial pressure. The indicated hydraulic pressure is relatively high until the engagement element starts to have the torque transmission capacity, in other words, until the piston for bringing the plate and the disk of the engagement element into pressure contact with each other to bring the frictional force into contact with the plate. By being maintained at 1 initial pressure, it is possible to shorten the time lag from the start of the engagement control until the engagement element starts to have the torque transmission capacity. Then, after the engaging element starts to have the torque transmission capacity, the rotation speed input to the automatic transmission starts to decrease from the peak, and the amount of decrease reaches a predetermined amount, in other words, the input to the automatic transmission. The command hydraulic pressure is lowered to and maintained at the relatively low second initial pressure until the rotational speed is sufficiently lowered. Accordingly, it is possible to suppress a synchronous shock that occurs when the rotation speed input to the automatic transmission is synchronized with the rotation speed output from the automatic transmission.

  Therefore, it is possible to achieve both reduction of the time lag and suppression of the synchronization shock.

  The first initial pressure is preferably set such that the shock caused by the piston of the engagement element coming into contact with the plate does not exceed an allowable level.

  The second initial pressure may be a constant value or may be gradually increased (sweep) over time.

  The control device may control the hydraulic circuit to execute the engagement control for engaging the engagement element when the vehicle equipped with the automatic transmission is started.

  In this case, the synchronous shock can be suppressed while the time lag from the start of the engagement control to the start of the vehicle equipped with the automatic transmission can be shortened.

  Further, the vehicle is a vehicle that uses an engine as a drive source, and is a vehicle in which idling stop control is performed to stop the engine when a predetermined engine stop condition is satisfied and restart the engine when the brake is released. May be.

  In this case, when returning from the idling stop, it is possible to suppress the synchronous shock while reducing the time lag from the start of engine cranking to the start of movement of the vehicle.

  According to the present invention, the time lag from the start of engagement control until the engagement element starts to have a torque transmission capacity is shortened, and the rotation speed input to the automatic transmission is synchronized with the rotation speed output from the automatic transmission. It is possible to achieve both suppression of the synchronous shock that occurs when

It is a figure which shows the structure of the principal part of the vehicle in which the control apparatus which concerns on one Embodiment of this invention is mounted. It is a skeleton diagram showing a configuration of a drive system of a vehicle. It is a figure which shows the state of each engagement element in P range, R range, N range, and D range. It is a flow chart which shows the contents of engagement control. It is a figure which shows an example of the time change of the instruction | indication hydraulic pressure of a clutch at the time of a recovery from idling stop, an engine speed, a turbine speed, and the acceleration which arises in a vehicle. It is a figure which shows the example of setting of a turbine determination value. It is a figure for demonstrating the result of the complete explosion determination and turbine rotation determination when the accelerator is off. It is a figure for demonstrating the result of the complete explosion determination and turbine rotation determination when the accelerator is on. It is a flow chart which shows the contents of throttle control. It is a figure which shows an example of the time change of the turbine speed, the accelerator opening, the throttle opening, and the acceleration which arises in a vehicle at the time of a recovery from idling stop. FIG. 9 is a diagram showing an example of a change over time in an instructed hydraulic pressure of a clutch, an engine speed, a turbine speed, and an acceleration generated in a vehicle in conventional engagement control.

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

<Structure of essential parts of vehicle>
FIG. 1 is a diagram showing a configuration of a main part of a vehicle 1 equipped with a control device according to an embodiment of the present invention.

  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 a torque converter 3 and a stepped automatic transmission (AT) 4. The engine 2 includes an electronic throttle valve 71 for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) 72 for injecting fuel into intake air, and a spark plug 73 for causing electric discharge in the combustion chamber. Etc. are provided. Further, the engine 2 is provided with a starter (not shown) for starting the engine.

  The vehicle 1 is equipped with 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 AT ECU 12, a brake ECU 13, and an IDS (idling stop) ECU 14. The plurality of ECUs are connected to each other so as to be capable of bidirectional communication according to a CAN (Controller Area Network) communication protocol.

  An accelerator sensor 21, an engine speed sensor 22, a throttle opening sensor 23, etc. are connected to the engine ECU 11.

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

  The engine speed sensor 22 outputs a pulse signal in synchronization with the rotation of the engine 2 (rotation of the crankshaft) as a detection signal. The engine ECU 11 converts the frequency of the pulse signal input from the engine rotation speed sensor 22 into the rotation speed of the engine 2 (engine rotation speed).

  The throttle opening sensor 23 outputs a detection signal corresponding to the opening of the electronic throttle valve 71 (throttle opening).

  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 information obtained from detection signals of various sensors and / or various information input from other ECUs. The throttle valve 71, the injector 72, the spark plug 73, etc. are controlled.

  A shift position sensor 24, a turbine speed sensor 25, and the like are connected to the AT ECU 12.

  The shift position sensor 24 outputs a detection signal according to the position of the shift lever (select lever). As positions of the shift lever, for example, a P position (parking position), an R position (reverse position), an N position (neutral position) and a D position (drive position) are provided. The P position, R position, N position and D position correspond to the P range, R range, N range and D range, respectively. The shift lever can be operated to shift between the P position, the R position, the N position and the D position, and the range operation can be instructed by the shift operation.

  The turbine rotation speed sensor 25 outputs a pulse signal in synchronization with the rotation of the turbine runner 32 (see FIG. 2) of the torque converter 3 as a detection signal. The AT ECU 12 converts the frequency of the pulse signal input from the turbine rotation speed sensor 25 into the turbine rotation speed that is the rotation speed of the turbine runner 32.

  The AT ECU 12 changes the range or the shift stage of the automatic transmission 4 based on the information acquired from the detection signals of the various sensors and / or the various information input from other ECUs. A valve included in the hydraulic circuit 74 for supplying hydraulic pressure to the valve is controlled.

  The valves include a C2 solenoid valve 75 and the like for controlling the hydraulic pressure supplied to the clutch C2 (see FIG. 2). As the C2 solenoid valve 75, a valve whose output hydraulic pressure can be controlled by a current value, for example, a linear solenoid valve is used.

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

  The brake sensor 26 outputs a detection signal according to the operation amount of a brake pedal arranged in the vehicle compartment.

  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 a non-contact manner with the rotor. Each time the rotor rotates by a certain angle, a pulse signal is output as a detection signal from the electromagnetic pickup. Since the frequency of the pulse signal corresponds to the vehicle speed, the brake ECU 13 converts the frequency of the pulse signal input from the vehicle speed sensor 27 into the vehicle speed.

  The brake ECU 13 controls the brake actuator 76 and the like on the basis of the information (the operation amount of the brake pedal, the vehicle speed of the vehicle 1) acquired from the detection signals of various sensors and / or various information input from other ECUs. The braking force applied from each brake to the wheels is controlled so that the vehicle 1 is braked while the posture of the vehicle 1 is kept stable.

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

  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 equal to or lower than a predetermined idling stop execution vehicle speed (for example, 10 km / h), and that the brake pedal is operated for a certain time or longer. When the engine stop condition is satisfied, the IDSECU 14 outputs an IDS request to the engine ECU 11, and the engine ECU 11 automatically stops the engine 2 (idling stop).

  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. In response to this restart request, the engine ECU 11 restarts the engine 2 (returns from idling stop).

<Drive system configuration>
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. The output shaft (E / G output shaft) of the engine 2 is connected to the pump impeller 31, and the pump impeller 31 is integrally rotatably provided around the same rotation axis as the E / G output shaft. ing. The turbine runner 32 is provided so as 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 while the lockup clutch 33 is released, the pump impeller 31 rotates. When the pump impeller 31 rotates, a flow of oil from the pump impeller 31 toward the turbine runner 32 occurs. 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 power larger than the power (torque) of the E / G output shaft.

  When the E / G output shaft is rotated while the lockup clutch 33 is engaged, the E / G output shaft, the pump impeller 31, and the turbine runner 32 rotate integrally.

  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 rotatably provided integrally with the pump impeller 31. As a result, 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 74.

  The automatic transmission 4 is a 4-speed AT having four shift stages of forward movement and one reverse movement. 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 provided on the same rotation axis line as the input shaft 41, separated from the input shaft 41 on the side opposite to the engine 2 side.

  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 onto 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 fitted onto 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 rotatably provided integrally with the center shaft 43. The carrier 53 rotatably supports a long pinion gear 55 and a short pinion gear 56. The ring gear 54 has an annular shape surrounding the periphery of the carrier 53 outside the rear sun gear 52 in the radial direction of rotation, 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. The short pinion gear 56 meshes with the rear sun gear 52 and the 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 meshed with the second output gear 62 which is supported by the output shaft 42 so as not to rotate relative to it. A third output gear 63 is supported by the output shaft 42 so as not to rotate relative to it, and the third output gear 63 meshes with a ring gear 64 provided in the differential gear 6. Accordingly, 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.

  Further, 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) that connects the input shaft 41 and the front sun gear 51 and a released state (off) that releases 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 B1 is switched between an engaged state (on) where the front sun gear 51 is braked and a released state (off) where the rotation of the front sun gear 51 is allowed.

  The brake B2 is switched between an engaged state (on) for braking the carrier 53 and a released state (off) for allowing the rotation of the carrier 53.

  The one-way clutch F allows only the forward rotation of the carrier 53 (rotation in the same direction as the output shaft of the engine 2).

  FIG. 3 is a diagram showing 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 in the engaged state. Further, it shows that the one-way clutch F is in an engaged state in which the reverse rotation of the carrier 53 is prevented.

  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, the clutch C1 and the brake B2 are engaged, and the clutches C2, C3 and the brake B1 are released.

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

  At 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.

  At the third speed in 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.

<Engagement control>
FIG. 4 is a flowchart showing the content of the engagement control. FIG. 5 is a diagram showing an example of a change over time in the command hydraulic pressure of the clutch C2, the engine speed, the turbine speed, and the acceleration generated in the vehicle 1 when returning from the idling stop.

  When the engine restart condition is satisfied after the engine 2 is automatically stopped by the idling stop control, cranking of the engine 2 is started (time T1). Further, when the shift lever is located at the D position, the AT ECU 12 starts engagement control for engaging the clutch C2 forming the first gear (time T1).

  In the engagement control, the AT ECU 12 executes each process described below.

  First, it is determined whether or not the state of the complete explosion determination flag provided in the RAM of the AT ECU 12 is ON (step S1). The complete explosion determination flag is a flag indicating whether or not the engine 2 has completed complete explosion. At the start of the engagement control, the complete explosion determination flag is reset to 0, so that the state of the complete explosion determination flag is turned off. When the engine 2 is cranked and the spark plug of the engine 2 is sparked, the engine 2 completes an explosion and the engine speed increases to a predetermined engine determination value (for example, 400 rpm). When 1 is set, the state of the complete explosion determination flag is turned on.

  When the state of the complete explosion determination flag is off (NO in step S1), it is next determined whether or not the state of the turbine rotation determination flag provided in the RAM of the AT ECU 12 is on (step S2). .. The turbine rotation determination flag is a flag that indicates whether or not the turbine rotation speed has risen to a predetermined turbine determination value. At the start of the engagement control, the turbine rotation determination flag is reset to 0, so that the state of the turbine rotation determination flag is turned off. When the turbine speed increases as the engine speed increases, and the turbine speed reaches the turbine determination value, the turbine rotation determination flag is set to 1 to turn on the turbine rotation determination flag. ..

  While each state of the complete explosion determination flag and the turbine rotation determination flag is off (NO in step S2), as a filling control for accelerating the filling of the clutch C2 with oil, the target value of the hydraulic pressure supplied to the clutch C2 is used. A certain command hydraulic pressure is maintained at the filling pressure (step S3, time T1-T2). The command hydraulic pressure of the clutch C2 corresponds to the current value input to the C2 solenoid valve 75 (see FIG. 1) for controlling the hydraulic pressure supplied to the clutch C2. Oil is supplied to the clutch C2 by controlling the current value supplied to the C2 solenoid valve 75 to a current value according to the filling pressure.

  When the engine speed increases to the engine determination value (YES in step S1), the state of the complete explosion determination flag is turned on (time T2). Then, it is determined whether or not the state of the clutch contact flag provided in the RAM of the AT ECU 12 is ON (step S4). The clutch contact flag is a flag that indicates whether or not a piston for bringing the clutch plate of the clutch C2 and the clutch disc into pressure contact with each other to generate a friction force has contacted the clutch plate. At the start of the engagement control, the state of the clutch contact flag is turned off by resetting the clutch contact flag to zero.

  While the state of the complete explosion determination flag is ON and the state of the clutch contact flag is OFF (NO in step S4), the command hydraulic pressure is maintained at the first initial pressure lower than the filling pressure (step S5, time). T2-T3). The first initial pressure is set to a value at which the shock generated when the piston of the clutch C2 contacts the clutch plate does not exceed the allowable level.

  When the filling of oil into the clutch C2 is completed and the piston comes into contact with the clutch plate, the clutch C2 starts to engage while sliding, so that the clutch C2 begins to have a torque transmission capacity. As the torque transmission capacity of the clutch C2 increases, the turbine speed decreases from the peak. When it is detected that the turbine rotation speed has dropped by the first predetermined amount (for example, 30 rpm), the clutch contact flag is set to 1 so that the state of the clutch contact flag is turned on (time T3). .

  When the state of the clutch contact flag is turned on (YES in step S4), it is determined whether or not the state of the rotation lowering flag provided in the RAM of the AT ECU 12 is on (step S6). The rotation descent flag is a flag indicating whether or not the turbine rotation speed has dropped by a second predetermined amount (for example, 50 rpm) larger than the first predetermined amount. At the start of the engagement control, the rotation lowering flag is reset to 0, so that the state of the rotation lowering flag is turned off.

  While the state of the clutch contact flag is on and the state of the rotation lowering flag is off (NO in step S6), the command hydraulic pressure is maintained at the second initial pressure lower than the first initial pressure (step S7, Time T3-T4).

  When it is detected that the turbine rotation speed has decreased by the second predetermined amount, the rotation lowering flag is set to 1 to turn on the state of the rotation lowering flag (time T4).

  After that, the commanded hydraulic pressure is gradually increased from the second initial pressure by sweeping at a constant time change rate (time gradient) (step S8, time T4 to T5). As a result, the engagement of the clutch C2 progresses, and the turbine rotation speed decreases.

  After the start of the sweep, it is determined whether or not the state of the synchronization detection flag provided in the RAM of the AT ECU 12 is ON (step S9). The synchronization detection flag is a flag that indicates whether or not it is detected that the turbine speed matches the first speed synchronous speed, that is, whether or not turbine speed synchronization is detected. At the start of the engagement control, the state of the synchronization detection flag is turned off by resetting the synchronization detection flag to zero. The 1st speed synchronous rotation speed is the rotation speed of the input shaft 41 (see FIG. 2) that is synchronized with the rotation speed of the output shaft 42 (see FIG. 2) when the shift stage of the automatic transmission 4 constitutes the 1st speed stage. Is.

  When the engagement of the clutch C2 progresses and the slippage of the clutch C2 disappears, the decrease of the turbine rotation speed stops and the turbine rotation speed matches the first speed synchronous rotation speed. When it is detected that the turbine rotation speed matches the first speed synchronous rotation speed, the synchronization detection flag is set to 1 to turn on the state of the synchronization detection flag (time T5). Then, the command hydraulic pressure is raised to the maximum pressure, and the engagement control is ended.

<Filling control time>
FIG. 6 is a diagram illustrating a setting example of the turbine determination value.

  The turbine determination value is variably set according to the accelerator opening.

  For example, as the accelerator opening is larger, the turbine determination value is set to a larger value stepwise. In a specific example, the turbine determination value is set to 30 rpm when the accelerator opening is 0%. When the accelerator opening is within the range of 0 to 50% (not including the lower limit and including the upper limit), the turbine determination value is set to 50 rpm and the accelerator opening is within the range of 50 to 100% (lower limit). Value is not included, and the upper limit value is included.), The turbine determination value is set to 100 rpm.

  7A is a diagram for explaining the results of the complete explosion determination and the turbine rotation determination when the accelerator is off, and FIG. 7B is a diagram for explaining the results of the complete explosion determination and the turbine rotation determination when the accelerator is on. It is a figure.

  As shown by the solid lines in FIGS. 7A and 7B, when the rotation speed of the engine 2 after the complete explosion rises quickly, the engine rotation speed is increased before the time T21 when the turbine rotation speed reaches the turbine determination value. The judgment value is reached (time T2). Therefore, in response to the engine speed increasing to the engine determination value, the command hydraulic pressure is reduced from the filling pressure to the first initial pressure.

  On the other hand, when the increase in the engine speed after the complete explosion of the engine 2 is slow, as shown by the two-dot chain line in FIGS. 7A and 7B, before the time T22 when the engine speed reaches the engine determination value, The turbine speed reaches the turbine determination value (time T21). Then, in response to the turbine rotation speed increasing to the turbine determination value, the turbine rotation determination flag is set to 1 so that the state of the turbine rotation determination flag is turned on, and the command hydraulic pressure changes from the filling pressure to the first pressure. Reduced to 1 initial pressure.

  Therefore, regardless of the degree of increase in the number of revolutions of the engine 2 after the complete explosion, it is possible to prevent the time (filling control time) in which the command hydraulic pressure is maintained at the filling pressure from being unnecessarily prolonged.

  Further, when the accelerator pedal is depressed (when the accelerator is on), the turbine determination value is set to a larger value than when the accelerator pedal is not depressed (when the accelerator is off). As a result, as can be understood by comparing FIGS. 7A and 7B, in the case of accelerator on, it takes a longer time for the turbine speed to rise to the turbine determination value than in the case of accelerator off. Therefore, when the accelerator is on, the time period during which the instruction pressure is held at the filling pressure becomes longer than when the accelerator is off.

<Throttle control>
FIG. 8 is a flowchart showing the contents of throttle control. FIG. 9 is a diagram showing an example of a temporal change of the turbine speed, the accelerator opening, the throttle opening, and the acceleration generated in the vehicle 1 when returning from the idling stop.

  At the time of returning from the idling stop, a command is output from the AT ECU 12 to the engine ECU 11, and upon receipt of this command, the engine ECU 11 executes the throttle control shown in FIG.

  In the throttle control, it is determined whether or not the accelerator is on (step S11). When the accelerator opening is less than a predetermined value (for example, less than 1.0% and may be 0%), it is determined that the accelerator pedal is not depressed and the accelerator is off, and the accelerator is opened. If the degree is equal to or higher than the predetermined value, it is determined that the accelerator pedal is depressed and the accelerator is on.

  When the accelerator is off (NO in step S11), the throttle opening which is the opening of the electronic throttle valve 71 (see FIG. 1) is not limited and the throttle control is ended.

  If the accelerator is on (YES in step S11), it is determined whether the rotation descent flag is on (step S12).

  When the state of the rotation lowering flag is OFF (NO in step S12), the throttle opening is limited to 0% which is the first opening (step S13). That is, the oil is supplied to the clutch C2 by the engagement control executed at the time of returning from the idling stop control, and after the turbine speed has risen, the piston of the clutch C2 abuts the clutch plate and the torque of the clutch C2 is increased. The turbine speed drops from the peak as the transmission capacity increases. Until the turbine rotational speed drops by the second predetermined amount, the throttle opening is limited to 0% even if the accelerator is on.

  When the turbine speed drops from the peak by the second predetermined amount and the state of the rotation lowering flag changes from OFF to ON (YES in step S12, time T11), it is determined whether or not the state of the synchronization detection flag is ON. (Step S14).

  When the state of the synchronization detection flag is OFF (NO in step S14), the throttle opening is limited to the second opening (step S15). That is, the throttle opening is limited to the second opening from the time when the turbine rotation speed drops by the second predetermined amount until the turbine rotation speed matches the first speed synchronous rotation speed (time T11-T12). The second opening is set to a constant opening at which the torque input to the clutch C2 does not exceed the torque transmission capacity of the clutch C2.

  When the turbine rotation speed matches the first speed synchronous rotation speed and the state of the synchronization detection flag changes from off to on (YES in step S14, time T12), the throttle opening changes from the second opening for a certain time by sweeping. The rate (time gradient) is gradually increased (step S16).

  Then, when the throttle opening increases to a value corresponding to the accelerator opening (YES in step S17, time T13), the throttle control is ended.

<Effect>
As described above, in the engagement control for engaging the clutch C2 of the automatic transmission 4, the instruction hydraulic pressure is raised to the filling pressure and the instruction hydraulic pressure is maintained at the filling pressure for a predetermined time. After that, the command hydraulic pressure is reduced from the filling pressure to the first initial pressure, and the command hydraulic pressure is maintained at the first initial pressure until the clutch C2 starts to have the torque transmission capacity. When the clutch C2 starts to have a torque transmission capacity, the command hydraulic pressure is reduced from the first initial pressure to the second initial pressure, and the turbine rotational speed that is the rotational speed input to the automatic transmission 4 reaches the second predetermined amount from the peak. The indicated hydraulic pressure is maintained at the second initial pressure until the hydraulic pressure drops. Then, when the turbine rotational speed drops by the second predetermined amount, the command hydraulic pressure is increased by the sweep from the second initial pressure to the maximum pressure.

  In the conventional engagement control, after the command hydraulic pressure is maintained at the filling pressure, the command hydraulic pressure is maintained at a constant initial pressure. On the other hand, in the engagement control by the AT ECU 12, after the instruction hydraulic pressure is maintained at the filling pressure, the instruction hydraulic pressure is reduced to the second initial pressure in two steps after a period of being maintained at the first initial pressure. Until the clutch C2 starts to have the torque transmission capacity, in other words, the command hydraulic pressure is kept at the relatively high first initial pressure until the piston of the clutch C2 comes into contact with the clutch plate. The time lag until the clutch C2 starts to have the torque transmission capacity can be shortened. Then, after the clutch C2 starts to have the torque transmission capacity, the turbine rotation speed starts to decrease, the turbine rotation speed sufficiently decreases, and the command hydraulic pressure is relatively decreased until the decrease amount reaches the second predetermined amount. The second initial pressure, which is very low, is maintained. As a result, it is possible to suppress the synchronous shock that occurs at the time of synchronization when the turbine speed matches the first speed synchronous speed.

  Therefore, when returning from idling stop, the time lag from the start of cranking of the engine 2 to the start of movement of the vehicle 1 can be shortened, while suppressing the synchronous shock that occurs during synchronization when the turbine speed matches the first speed synchronous speed. You can

  In the engagement control, when the engine speed increases to the engine determination value or the turbine speed increases to the turbine determination value, the instruction hydraulic pressure is decreased from the filling pressure to the first initial pressure. As a result, when the engine speed increases at the time of starting the engine 2, the engine speed increases to the engine determination value before the turbine speed increases to the turbine determination value, and the command oil pressure changes from the filling pressure. It is lowered to the first initial pressure. On the other hand, when the increase in the engine speed at the time of starting the engine 2 is slow, the turbine speed increases to the turbine determination value before the engine speed increases to the engine determination value, and the command hydraulic pressure changes from the filling pressure to the first value. Reduced to 1 initial pressure. Therefore, regardless of the degree of increase in the engine speed at the time of engine start, it is possible to prevent wasteful prolongation of the time during which the command hydraulic pressure is maintained at the filling pressure. As a result, it is possible to suppress excessive hydraulic pressure in the clutch C2, and it is possible to suppress a contact shock that occurs when the piston of the clutch C2 contacts the clutch plate.

  The turbine determination value is set to a larger value stepwise as the accelerator opening is larger. Therefore, the larger the accelerator opening, the longer the instructed hydraulic pressure is kept at the filling pressure, and the shorter the time lag from the start of the engagement control to the start of the clutch C2 having the torque transmission capacity. .. As a result, when returning from the idling stop, the time lag from the start of the cranking of the engine 2 to the start of the movement of the vehicle 1 can be further shortened, and the starting feeling of the vehicle 1 according to the driver's intention can be realized.

  Even if the accelerator pedal of the vehicle 1 is operated before the clutch C2 starts to have the torque transmission capacity, the opening degree of the electronic throttle valve 71 is the first opening degree until the clutch C2 starts to have the torque transmission capacity. It is set to a certain 0% and the electronic throttle valve 71 is kept closed. After the clutch C2 starts to have the torque transmission capacity, the opening degree of the electronic throttle valve 71 is increased to the second opening degree. As a result, the torque output from the engine 2 increases, and the acceleration of the vehicle 1 starts when the vehicle 1 starts moving. Then, the second opening is set to a constant opening in which the torque input to the clutch C2 does not exceed the torque transmission capacity of the clutch C2. Therefore, even if the opening degree of the electronic throttle valve 71 is increased to the second opening degree, it is possible to suppress the upward rotation of the turbine.

  Therefore, while the start feeling can be improved by shortening the time lag from the start of the engine 2 to the start of movement of the vehicle 1, the turbine rotation speed is matched with the 1st speed synchronous rotation speed by suppressing the rise of the turbine rotation. It is possible to further suppress the synchronization shock that occurs at the time of synchronization.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can be implemented in other forms.

  Each of the first initial pressure and the second initial pressure may be a fixed value or may be a variable value.

  The first initial pressure may be variably set according to the accelerator opening, for example. Specifically, as the accelerator opening is larger, the first initial pressure may be set to a larger value stepwise or continuously. As a result, the larger the accelerator opening, the shorter the time lag from the start of the engagement control until the clutch C2 starts to have the torque transmission capacity. Therefore, the vehicle 1 according to the intention of the driver who operates the accelerator pedal can be reduced. It is possible to realize the starting feeling of.

  The second initial pressure may be variably set according to the accelerator opening, for example. Specifically, as the accelerator opening is larger, the second initial pressure may be set to a larger value stepwise or continuously. As a result, the larger the accelerator opening, the shorter the time lag from when the clutch C2 starts to have the torque transmission capacity until the turbine rotation speed is synchronized. Therefore, the vehicle 1 according to the intention of the driver who operates the accelerator pedal can be reduced. It is possible to realize the starting feeling of. Further, the second initial pressure is assumed to be a constant value, but may be gradually increased (sweep) with the lapse of time.

  In each of the above-described controls, the shift lever is shifted from the P position or the N position to the D position immediately after the engine 2 is started, not only when the engine is returned from the idling stop (when the engine 2 is restarted by the idling stop control). It may be executed in some cases.

  Each sensor described above is merely an example of a sensor related to the present invention, and other sensors may be connected to the engine ECU 11, the AT ECU 12, the brake ECU 13, and the IDSECU 14.

  Further, some or all of the functions of engine ECU 11, AT ECU 12, brake ECU 13, and IDSECU 14 may be integrated into one ECU.

  Further, although the configuration in which the vehicle 1 is equipped with the stepped automatic transmission 4 has been taken up, the present invention is directed to a continuously variable transmission or a power split type continuously variable transmission equipped with a clutch that is engaged when the vehicle starts. It can also be applied to vehicles equipped with machines. The power split type continuously variable transmission includes a belt type continuously variable transmission mechanism that continuously changes the power by changing the gear ratio and a constant transmission mechanism that changes the power at a constant gear ratio. Is a transmission that can be divided into two systems for transmission.

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

4 Automatic transmission 12 AT ECU (control unit)
74 Hydraulic circuit C2 Clutch (engagement element)

Claims (1)

A control device for an automatic transmission including a hydraulic circuit and an engagement element that is engaged by hydraulic pressure supplied from the hydraulic circuit,
Controlling the hydraulic circuit of the automatic transmission to perform engagement control for engaging the engagement elements of the automatic transmission,
In the engagement control,
A filling process of increasing the instruction hydraulic pressure, which is a target value of the hydraulic pressure supplied to the engagement element, to the filling pressure, and maintaining the instruction hydraulic pressure at the filling pressure for a predetermined time,
After the filling process, the instruction hydraulic pressure is reduced to the first initial pressure lower than the filling pressure, and the instruction hydraulic pressure is kept at the first initial pressure until the engagement element starts to have a torque transmission capacity. The first initial processing to
After the first initial processing, the instruction hydraulic pressure is reduced from the first initial pressure to a second initial pressure that is lower than the first initial pressure until the number of revolutions input to the automatic transmission drops by a predetermined amount. During the second, a second initial process of maintaining the indicated hydraulic pressure at the second initial pressure;
After the second initial process, a raising process for raising the command hydraulic pressure from the second initial pressure is executed ,
The larger the accelerator opening, the larger the first initial pressure is set,
A control device that sets the second initial pressure to a larger value as the accelerator opening is larger .

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