JP6647752B2 - Control device for automatic transmission - Google Patents

Description

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

  2. Description of the Related Art In recent years, so-called idling stop control has been widely adopted for vehicles driven by an engine for the purpose of improving fuel efficiency. In the idling stop control, for example, when the brake pedal is depressed with the driver's foot to operate the brake and the vehicle speed falls 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 (returned from idling stop).

  Some vehicles that adopt the 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 interior, and a clutch (brake) provided in the automatic transmission is engaged / disengaged according to the selected range. Specifically, in the P range and the N range, all clutches are released. In the R range, a specific clutch is engaged. In the D range, the clutch engaged in the R range is released, and a plurality of shift speeds are selectively configured by a combination of engagement and release of other clutches. The clutch is engaged / disengaged by hydraulic pressure.

  FIG. 10 is a diagram showing an example of temporal changes of the command oil pressure of the clutch, the engine speed, and the turbine speed when returning from the idling stop.

  During idling stop, since the mechanical oil pump driven by the power of the engine is stopped, the hydraulic pressure is released from each clutch of the automatic transmission and each clutch is released. Therefore, at the time of return from the idling stop, the control device for controlling the automatic transmission causes the clutch (for example, the clutch that constitutes the first speed stage when the shift lever is located at the D position corresponding to the D range) to be engaged. Engagement control is performed.

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

  When the engine is completely cranked by sparking the spark plug of the engine while the engine is being cranked, the cranking is terminated. Due to the complete explosion of the engine, the engine speed increases, and as the engine speed increases, the turbine speed, which is the speed of the turbine runner of the torque converter, increases.

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

  When it is determined that the engine has completely exploded, the command oil pressure of the clutch is reduced from the charging pressure to the initial pressure (time T102). Thereafter, the command oil pressure of the clutch is maintained at the initial pressure. Meanwhile, filling of the clutch with oil is completed (time T103). When the filling of the oil into the clutch is completed and the piston for generating frictional force by pressing the clutch plate and the clutch disk comes into contact with the clutch plate, the clutch starts to engage while slipping. Accordingly, 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 at a constant rate of change by sweeping.

  When the engagement of the clutch advances and the slippage of the clutch stops, the lowering of the turbine speed stops, and the output speed of the automatic transmission when the turbine speed is the first speed synchronous speed (the first speed stage is configured). Number of rotations synchronized with the number). When the synchronization of the turbine speed is detected (time T105), the command oil pressure of the clutch is increased to the maximum pressure, and the engagement control is terminated.

JP-A-2015-117738

  The manner in which the engine speed increases when the engine is started changes depending on the intake air temperature of the engine and the oxygen concentration in the intake air. As indicated by the two-dot chain line in FIG. 10, when the engine speed is slowly increased, it takes time for the engine speed to increase to the complete explosion determination engine speed, and the hydraulic pressure indicated by the clutch is maintained at the filling pressure. Since the time is long, the clutch has an excessive hydraulic pressure, and a contact shock may occur when the piston contacts the clutch plate.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a control device for an automatic transmission that can prevent uselessly prolonging a time during which an instruction hydraulic pressure is maintained at a filling pressure in engagement control for engaging an engagement element.

  To achieve the above object, a control device for an automatic transmission according to the present invention includes a hydraulic circuit and an engagement element that is engaged by hydraulic pressure supplied from the hydraulic circuit, and power from an engine is transmitted via a torque converter. A control device for an automatic transmission that is input and controls engagement of an engagement element of the automatic transmission by controlling a hydraulic circuit of the automatic transmission when the engine is started. In the engagement control, the command oil pressure, which is the target value of the oil pressure supplied to the engagement element, is raised to the filling pressure, the command oil pressure is held at the filling pressure, and while the command oil pressure is held at the filling pressure, In response to the engine speed increasing to the predetermined engine determination value or the turbine speed of the torque converter increasing to the predetermined turbine determination value, the indicated hydraulic pressure decreases to the initial pressure lower than the charging pressure. Let it.

  According to this configuration, at the time of starting the engine, engagement control for engaging the engagement element of the automatic transmission is performed. In this engagement control, the command oil pressure, which is the target value of the oil pressure supplied to the engagement element, is raised to the filling pressure, and the command oil pressure is held at the filling pressure. Thereafter, when the engine speed increases to a predetermined engine determination value or when the turbine speed of the torque converter increases to a predetermined turbine determination value, the indicated hydraulic pressure is reduced from the charging pressure to the initial pressure.

  Thus, when the engine speed at the start of the engine rises quickly, 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 charging pressure to the initial pressure. Can be lowered. On the other hand, if the increase in the engine speed at the start of the engine is slow, the turbine speed increases to the turbine determination value before the engine speed increases to the engine determination value, and the indicated oil pressure changes from the charging pressure to the initial pressure. Can be lowered. Therefore, regardless of the degree of increase of the engine speed at the time of starting the engine, it is possible to prevent the time during which the indicated hydraulic pressure is maintained at the filling pressure from being wasted. As a result, it is possible to suppress the engagement element from having an excessive hydraulic pressure, and suppress a contact shock generated when a piston for generating frictional force by pressing the plate of the engagement element and the disk comes into contact with the plate. can do.

  The turbine determination value may be variably set stepwise or continuously according to the operation amount of an accelerator operation member such as an accelerator pedal operated by the driver.

  For example, as the operation amount of the accelerator operation member increases, the turbine determination value may be gradually or continuously set to a large value.

  Thus, as the operation amount of the accelerator operation member is larger, the time during which the command hydraulic pressure is maintained at the filling pressure can be increased, and the time lag from the start of the engagement control to the time when the engagement element starts to have the torque transmission capacity is reduced. Can be shortened. As a result, the time lag from the start of the cranking of the engine to the start of the movement of the vehicle can be reduced, and the starting feeling of the vehicle according to the driver's intention can be realized.

  The vehicle equipped with the automatic transmission may be a vehicle in which idling stop control is executed to stop the engine when a predetermined engine stop condition is satisfied and restart the engine when the brake is released.

  In this case, the contact shock can be suppressed when returning from the idling stop.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that an engaging element becomes excessively hydraulic, and the contact which arises when a piston for making a plate and a disk of an engaging element press-contact and generate a frictional force contacts a plate. Shock can be suppressed.

It is a figure showing composition of an important section of a vehicle in which a control device concerning one embodiment of the present invention was carried. FIG. 2 is a skeleton diagram showing a configuration of a drive system of the vehicle. It is a figure showing the state of each engagement element in P range, R range, N range, and D range. It is a flowchart which shows the content of engagement control. FIG. 7 is a diagram illustrating an example of a temporal change of a command oil pressure of a clutch, an engine speed, a turbine speed, and acceleration generated in a vehicle when returning from an idling stop. It is a figure showing an example of setting of a turbine judgment value. It is a figure for explaining the result of complete explosion judgment and turbine rotation judgment in the case of accelerator off. It is a figure for explaining the result of complete explosion judgment and turbine rotation judgment at the time of accelerator on. 6 is a flowchart showing the details of throttle control. FIG. 7 is a diagram illustrating an example of a time change of a turbine rotation speed, an accelerator opening, a throttle opening, and acceleration generated in a vehicle when returning from an idling stop. FIG. 9 is a diagram showing an example of a temporal change of a command oil pressure of a clutch, an engine speed, and a turbine speed in conventional engagement control.

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

<Main components of the vehicle>
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 driven by the engine 2.

  The output of the engine 2 is transmitted to drive 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 air taken 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 generating electric discharge in the combustion chamber. And so on. The engine 2 is also provided with a starter (not shown) for starting the engine 2.

  The vehicle 1 is provided with a plurality of ECUs (Electronic Control Units) 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, an engine speed sensor 22, a throttle opening sensor 23, and the like 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 to the maximum operation amount of the accelerator pedal, that is, 0% when the accelerator pedal is not depressed, and depresses the accelerator pedal to the maximum. The accelerator opening degree, which is a percentage with the time being 100%, is calculated.

  The engine speed sensor 22 outputs a pulse signal synchronized with the rotation of the engine 2 (the rotation of the crankshaft) as a detection signal. 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 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 configured to start, stop, and adjust the output of the engine 2 based on information obtained from detection signals of various sensors and / or various information input from other ECUs. It controls the throttle valve 71, the injector 72, the spark plug 73, and the like.

  The ATECU 12 is connected with a shift position sensor 24, a turbine speed sensor 25, and the like.

  The shift position sensor 24 outputs a detection signal according to the position of the shift lever (select lever). As the 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, the R position, the N position, and the D position correspond to the P range, the R range, the N range, and the D range, respectively. The shift lever can perform a shift operation among a P position, an R position, an N position, and a D position, and can instruct switching of a range by the shift operation.

  The turbine speed sensor 25 outputs a pulse signal synchronized with the rotation of the turbine runner 32 (see FIG. 2) of the torque converter 3 as a detection signal. The ATECU 12 converts the frequency of the pulse signal input from the turbine speed sensor 25 into a turbine speed, which is the speed of the turbine runner 32.

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

  The valves include a C2 solenoid valve 75 for controlling the hydraulic pressure supplied to the clutch C2 (see FIG. 2). As the C2 solenoid valve 75, a valve whose output oil 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, and the like are connected to the brake ECU 13.

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

  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 as a detection signal. 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 based on information (operation amount of the brake pedal, vehicle speed of the vehicle 1) obtained from detection signals of various sensors and / or various information input from another ECU. The braking force applied to the wheels from each brake is controlled so that the vehicle 1 is braked while the posture of the vehicle 1 is kept stable.

  The vehicle 1 has an idling stop function. The IDSECU 14 executes an idling stop control which is a control for an idling stop function. 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 as information necessary for the idling stop control.

  In the idling stop control, when the brake pedal is operated (depressed) while the vehicle 1 is running, the IDSECU 14 repeatedly determines whether 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 the brake pedal is operated for a predetermined 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 (idling stop) by the engine ECU 11.

  During the automatic stop of the engine 2 by the idling stop control, it is repeatedly determined whether 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, a restart request is output from the IDSECU 14 to the engine ECU 11. In response to the restart request, the engine ECU 11 restarts the engine 2 (returns from idling stop).

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

  The torque converter 3 includes a pump impeller 31, a turbine runner 32, and a lock-up clutch 33. The output shaft (E / G output shaft) of the engine 2 is connected to the pump impeller 31. The pump impeller 31 is provided so as to be integrally rotatable about the same rotation axis as the E / G output shaft. ing. The turbine runner 32 is provided rotatable about the same rotation axis as the pump impeller 31. The lock-up clutch 33 is provided for directly connecting / disconnecting the pump impeller 31 and the turbine runner 32. When the lock-up clutch 33 is engaged, the pump impeller 31 and the turbine runner 32 are directly connected. When the lock-up 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 lock-up clutch 33 is released, the pump impeller 31 rotates. When the pump impeller 31 rotates, oil flows from the pump impeller 31 to the turbine runner 32. This oil flow is received by the turbine runner 32, and the turbine runner 32 rotates. At this time, an amplifying action of the torque converter 3 occurs, and a power larger than the power (torque) of the E / G output shaft is generated in the turbine runner 32.

  In a state where the lock-up 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 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 provided so as to be able to rotate integrally with the pump impeller 31. Thus, 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 a 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 forward speeds / one 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 spaced apart from the input shaft 41 on the side opposite to the engine 2 and is provided on the same rotation 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 around 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 with respect to the front sun gear 51, and is fitted around 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 surrounding the periphery of the carrier 53 on the outer side in the rotation radial direction of the rear sun gear 52, and meshes with the long pinion gear 55. Long pinion gear 55 has a shaft length longer than that of short pinion gear 56, and meshes with front sun gear 51. Short pinion gear 56 meshes with rear sun gear 52 and long pinion gear 55.

  The first output gear 61 is held by the ring gear 54 so as to have a common rotation axis. The first output gear 61 is meshed with a second output gear 62 supported on the output shaft 42 so as not to rotate relatively. A third output gear 63 is supported by the output shaft 42 so as not to rotate relatively. The third output gear 63 is engaged with a ring gear 64 provided in the differential gear 6. Thus, 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) 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 B1 is switched between an engaged state (on) for braking the front sun gear 51 and a released state (off) for allowing rotation of the front sun gear 51.

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

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

  FIG. 3 is a diagram showing the states of the clutches C1 to C3, the brakes B1, 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. Also, it indicates that the one-way clutch F is in the engaged state for preventing 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, the clutch C1 and the brake B2 are engaged, and the clutches C2 and C3 and the brake B1 are released.

  In the first gear of the D range, the clutch C2 is engaged, and the clutches C1, C3 and the brakes B1, B2 are released.

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

  In the fourth speed range of 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 illustrating an example of a change over time of the command oil 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.

  After the engine 2 is automatically stopped by the idling stop control and the engine restart condition is satisfied, the cranking of the engine 2 is started (time T1). When the shift lever is located at the D position, the ATECU 12 starts engagement control for engaging the clutch C2 constituting the first speed (time T1).

  In the engagement control, the processing described below is executed by the ATECU 12.

  First, it is determined whether or not the complete explosion determination flag provided in the RAM of the ATECU 12 is ON (step S1). The complete explosion determination flag is a flag indicating whether or not the engine 2 has completely exploded. At the start of the engagement control, the complete explosion determination flag is turned off by resetting the complete explosion determination flag to zero. When the spark plug of the engine 2 is sparked while the engine 2 is being cranked, the engine 2 completely explodes. When the engine speed increases to a predetermined engine determination value (for example, 400 rpm), the complete explosion determination flag is set. 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 the state of the turbine rotation determination flag provided in the RAM of the ATECU 12 is on (step S2). . The turbine rotation determination flag is a flag indicating whether or not the turbine rotation speed has increased to a predetermined turbine determination value. At the start of the engagement control, the state of the turbine rotation determination flag is turned off by resetting the turbine rotation determination flag to 0. When the turbine speed increases with an increase in the engine speed 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 oil into the clutch C2, the target value of the hydraulic pressure supplied to the clutch C2 is used. A certain command oil pressure is held at the filling pressure (step S3, time T1-T2). The command oil pressure of the clutch C2 corresponds to a current value input to a C2 solenoid valve 75 (see FIG. 1) for controlling the oil pressure supplied to the clutch C2. By controlling the current value supplied to the C2 solenoid valve 75 to a current value corresponding to the filling pressure, oil is supplied to the clutch C2.

  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 the state of the clutch contact flag provided in the RAM of the ATECU 12 is on (step S4). The clutch contact flag is a flag indicating whether or not the piston for generating a frictional force by pressing the clutch plate of the clutch C2 and the clutch disk 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 0.

  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 indicated hydraulic pressure is maintained at the first initial pressure lower than the charging pressure (step S5, time). T2-T3). The first initial pressure is set to a value at which the shock generated by the contact of the piston of the clutch C2 with the clutch plate does not exceed the allowable level.

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

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

  While the state of the clutch contact flag is ON and the state of the rotation descent flag is OFF (NO in step S6), the command oil 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 dropped by the second predetermined amount, the rotation descent flag is set to 1 and the state of the rotation descent flag is turned on (time T4).

  Thereafter, the command oil pressure is gradually increased from the second initial pressure by a sweep at a constant time rate of change (time gradient) (step S8, times T4 to T5). As a result, the engagement of the clutch C2 proceeds, and the turbine speed decreases.

  After the start of the sweep, it is determined whether the state of the synchronization detection flag provided in the RAM of the ATECU 12 is on (step S9). The synchronization detection flag is a flag indicating whether or not it is detected that the turbine rotation speed matches the first-speed synchronization rotation speed, that is, whether or not synchronization of the turbine rotation speed has been 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 0. The first-speed synchronous rotation speed is the rotation speed of the input shaft 41 (see FIG. 2) synchronized with the rotation speed of the output shaft 42 (see FIG. 2) when the shift speed of the automatic transmission 4 constitutes the first speed. It is.

  When the engagement of the clutch C2 advances and the slippage of the clutch C2 stops, the decrease in the turbine speed stops, and the turbine speed matches the first-speed synchronous speed. When it is detected that the turbine rotational speed matches the first-speed synchronous rotational speed, the synchronous detection flag is set to 1 to turn on the state of the synchronous detection flag (time T5). Then, the command oil pressure is increased 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 increases, the turbine determination value is set to a gradually larger value. In a specific example, when the accelerator opening is 0%, the turbine determination value is set to 30 rpm. When the accelerator opening is within the range of 0 to 50% (not including the lower limit, but 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). In this case, the turbine determination value is set to 100 rpm.

  FIG. 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. FIG.

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

  On the other hand, when the increase in the rotation speed of the engine 2 after the complete explosion is slow, as indicated by the two-dot chain line in FIGS. 7A and 7B, before the time T22 when the engine rotation speed reaches the engine determination value, The turbine speed reaches the turbine determination value (time T21). Then, in response to the turbine rotation speed rising to the turbine determination value, the turbine rotation determination flag is set to 1 by turning on the turbine rotation determination flag, and the indicated hydraulic pressure is changed from the charging pressure to the third pressure. 1 Reduced to initial pressure.

  Therefore, regardless of the degree of increase in the number of revolutions of the engine 2 after the complete explosion, the time during which the indicated hydraulic pressure is maintained at the filling pressure (filling control time) is prevented from being wastefully 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). Accordingly, as understood from a comparison between FIG. 7A and FIG. 7B, it takes a longer time for the turbine speed to rise to the turbine determination value in the case of the accelerator on than in the case of the accelerator off. Therefore, when the accelerator is on, the time during which the command pressure is maintained at the filling pressure is longer than when the accelerator is off.

<Throttle control>
FIG. 8 is a flowchart showing the details of the throttle control. FIG. 9 is a diagram illustrating an example of a time 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.

  When returning from idling stop, a command is output from the ATECU 12 to the engine ECU 11, and in response to 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). If the accelerator opening is less than a predetermined value (for example, less than 1.0%, or 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 greater than the predetermined value, it is determined that the accelerator pedal is depressed and the accelerator is on.

  If 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 ends.

  If the accelerator is on (YES in step S11), it is determined whether or not the state of the rotation descent flag is on (step S12).

  When the state of the rotation descent flag is off (NO in step S12), the throttle opening is limited to 0%, which is the first opening (step S13). That is, by the engagement control executed when returning from the idling stop control, oil is supplied to the clutch C2, and after the turbine speed is increased, the piston of the clutch C2 comes into contact with the clutch plate and the torque of the clutch C2 is increased. As the transmission capacity increases, the turbine speed falls from the peak. Until the turbine speed drops by the second predetermined amount, the throttle opening is limited to 0% even in the accelerator-on state.

  When the turbine speed drops by a second predetermined amount from the peak and the state of the rotation descent 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 speed drops by the second predetermined amount to the time when the turbine speed matches the first-speed synchronous 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 rotational speed matches the first-speed synchronous rotational speed and the state of the synchronous detection flag changes from off to on (YES in step S14, time T12), the throttle opening changes from the second opening by a certain time by sweeping. It is gradually increased at a rate (time gradient) (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 ends.

<Effects>
As described above, in the engagement control for engaging the clutch C2 of the automatic transmission 4, the command oil pressure is increased to the filling pressure, and the command oil pressure is held at the filling pressure for a predetermined time. Thereafter, the command oil pressure is reduced from the filling pressure to the first initial pressure, and the command oil pressure is held at the first initial pressure until the clutch C2 starts to have the torque transmission capacity. When the clutch C2 starts to have the torque transmission capacity, the command oil pressure is reduced from the first initial pressure to the second initial pressure, and the turbine speed, which is the speed input to the automatic transmission 4, becomes the second predetermined amount from the peak. The command hydraulic pressure is maintained at the second initial pressure until the pressure drops. Then, when the turbine speed drops by the second predetermined amount, the command oil pressure is increased by sweeping from the second initial pressure to the maximum pressure.

  In the conventional engagement control, after the command oil pressure is maintained at the filling pressure, the command oil pressure is maintained at a constant initial pressure. On the other hand, in the engagement control by the ATECU 12, after the command oil pressure is held at the filling pressure, the pressure is reduced to the second initial pressure in two stages after a period in which the command oil pressure is held at the first initial pressure. Until the clutch C2 starts to have the torque transmission capacity, in other words, until the piston of the clutch C2 comes into contact with the clutch plate, the indicated hydraulic pressure is held at the relatively high first initial pressure. The time lag until the clutch C2 starts to have the torque transmission capacity can be reduced. Then, after the clutch C2 starts to have the torque transmission capacity, the turbine rotational speed starts to drop, and the indicated hydraulic pressure becomes relatively low until the turbine rotational speed drops sufficiently and the drop amount reaches the second predetermined amount. And the second initial pressure is kept low. As a result, it is possible to suppress a synchronization shock that occurs at the time of synchronization when the turbine speed matches the first-speed synchronous speed.

  Therefore, when returning from the idling stop, it is possible to reduce the time lag from the start of cranking of the engine 2 to the start of the movement of the vehicle 1 and to suppress the synchronization shock generated at the time of synchronization when the turbine rotation speed matches the first-speed synchronization rotation speed. Can be.

  In the engagement control, when the engine speed increases to the engine determination value or when the turbine speed increases to the turbine determination value, the command oil pressure is reduced from the charging pressure to the first initial pressure. Thus, when the engine speed at the start of the engine 2 increases rapidly, 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 charging pressure. The pressure is reduced to the first initial pressure. On the other hand, if the increase in the engine speed at the start of the engine 2 is slow, before the engine speed increases to the engine determination value, the turbine speed increases to the turbine determination value, and the indicated oil pressure changes from the charging pressure to the third pressure. 1 Reduced to initial pressure. Therefore, regardless of the degree of increase in the engine speed at the time of engine start, it is possible to suppress the time in which the command oil pressure is maintained at the filling pressure from being wasted. As a result, it is possible to prevent the clutch C2 from having an excessive oil pressure, and it is possible to suppress a contact shock generated when the piston of the clutch C2 contacts the clutch plate.

  The turbine determination value is set to a gradually larger value as the accelerator opening is larger. Therefore, as the accelerator opening increases, the time during which the command oil pressure is maintained at the filling pressure can be lengthened, and the time lag from the start of the engagement control until the clutch C2 starts to have the torque transmission capacity can be reduced. . As a result, when returning from the idling stop, the time lag from the start of cranking of the engine 2 to the start of the movement of the vehicle 1 can be further reduced, and the starting feeling of the vehicle 1 according to the driver's intention can be realized.

  Also, even if the accelerator pedal of the vehicle 1 is operated before the clutch C2 starts to have the torque transmission capacity, the opening of the electronic throttle valve 71 remains at the first opening 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 of the electronic throttle valve 71 is increased to the second opening. As a result, the torque output from the engine 2 increases, and the acceleration of the vehicle 1 increases as the vehicle 1 starts moving. 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. Therefore, even if the opening of the electronic throttle valve 71 is increased to the second opening, it is possible to suppress the turbine rotation from rising.

  Therefore, the start feeling can be improved by shortening the time lag from the start of the engine 2 to the start of the movement of the vehicle 1, and the turbine speed matches the first speed synchronous speed by suppressing the turbine speed from rising. Synchronization shock generated at the time of synchronization can be further suppressed.

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

  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, for example, according to the accelerator opening. Specifically, the first initial pressure may be set to a larger value stepwise or continuously as the accelerator opening is larger. As a result, as the accelerator opening increases, the time lag from the start of the engagement control to the time when the clutch C2 starts to have the torque transmission capacity can be reduced, so that the vehicle 1 according to the driver's intention of operating the accelerator pedal Starting feeling can be realized.

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

  Each of the above-described controls is not limited to the return from the idling stop (when the engine 2 is restarted by the idling stop control), and the shift lever is shifted from the P position or the N position to the D position immediately after the start of the engine 2. It may be performed in the case.

  The above-described sensors are merely examples of sensors related to the present invention, and other sensors may be connected to the engine ECU 11, the ATECU 12, the brake ECU 13, and the IDSECU 14.

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

  Also, the configuration in which the vehicle 1 is equipped with the stepped automatic transmission 4 has been described. However, the present invention relates to a continuously variable transmission including a clutch engaged when the vehicle starts moving or a power split type continuously variable transmission. The present invention can also be applied to a vehicle equipped with a device. The power split type continuously variable transmission includes a belt-type continuously variable transmission mechanism that continuously changes the power by changing the speed ratio, and a constant transmission mechanism that changes the power at a constant speed ratio. Can be divided into two systems and transmitted.

  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 3 Torque converter 4 Automatic transmission 12 ATECU (control device)
74 hydraulic circuit C2 clutch (engagement element)

Claims (1)

A control device for an automatic transmission, comprising a hydraulic circuit and an engagement element that is engaged by hydraulic pressure supplied from the hydraulic circuit, wherein power from an engine is input via a torque converter,
At the time of starting the engine, controlling the hydraulic circuit of the automatic transmission to execute engagement control for engaging the engagement element of the automatic transmission,
In the engagement control,
The command oil pressure, which is a target value of the oil pressure supplied to the engagement element, is increased to a filling pressure, and the command oil pressure is held at the filling pressure.
While the command oil pressure is held at the charging pressure, the engine speed has increased to a predetermined engine determination value, or the turbine speed of the torque converter has increased to a predetermined turbine determination value. In response to reducing the command oil pressure to an initial pressure lower than the filling pressure ,
At this time, before the turbine speed increases to the turbine determination value, if the engine speed increases to the engine determination value, the command oil pressure is reduced from the charging pressure to the initial pressure, and , before the rotational speed of the engine is increased to the engine determination value, when the turbine speed increases in the turbine judgment value, Ru said command oil pressure is lowered to the initial pressure from the charging pressure, the control device .

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