JP6855119B2 - Control device for continuously variable transmission - Google Patents

Description

The present invention relates to a control device for a continuously variable transmission.

As a transmission mounted on a vehicle, for example, a continuously variable transmission (CVT) having a configuration in which an endless belt is wound around a primary pulley on the input side and a secondary pulley on the output side is known. ing.

By continuously changing the groove width of each pulley of the primary pulley and the secondary pulley, the winding diameter of the belt for each pulley can be changed, and the gear ratio (pulley ratio) is continuously changed steplessly. be able to. Further, the gear ratio can be changed stepwise by changing the groove width of each pulley stepwise. Therefore, in a continuously variable transmission, in addition to stepless speed change control that changes the gear ratio steplessly, shift control that has a different control rule from stepless speed change control, for example, stepped speed change that changes the gear ratio stepwise. Acceleration shift control such as control can be executed.

Special Fair 7-102790

For example, the driver's acceleration request is determined from the mode of accelerator operation by the driver, and the continuously variable transmission control is switched to the continuously variable transmission control according to the determination of the acceleration request, and the gear ratio of the continuously variable transmission is constant. By being held at, it is possible to obtain a linear acceleration response or a feeling of acceleration according to the accelerator operation.

However, depending on the traveling condition of the vehicle, the continuously variable transmission control and the stepped transmission control may be switched without the driver's intention.

An object of the present invention is to provide a control device for a continuously variable transmission capable of suppressing switching between stepless speed change control and stepped speed change control that is not intended by the driver.

In order to achieve the above object, the continuously variable transmission control device according to the present invention is used in a vehicle equipped with a continuously variable transmission capable of continuously shifting the power from a drive source, and the continuously variable transmission is used. a control apparatus for controlling a machine, vehicle uphill to the uphill determining means for determining whether the shift of the continuously variable control and the continuously variable transmission to shift the gear ratio of the continuously variable transmission with steplessly The shift control means includes a shift control means for selectively executing a stepped shift control in which the ratio is changed stepwise according to a control rule different from that of the continuously variable transmission control, and the shift control means determines climbing during the execution of the stepped shift control. When the climbing is determined by the means, the execution of the stepped speed change control is continued for a predetermined period from the determination.

According to this configuration, stepless speed change control and stepped speed change control are selectively executed. In the continuously variable transmission control, the gear ratio of the continuously variable transmission is changed steplessly. In the stepped speed change control, the gear ratio of the continuously variable transmission is changed according to a control rule different from that of the stepless speed change control so that an acceleration feeling corresponding to the driver's acceleration request can be obtained.

If uphill by uphill determining means during execution of the step-variable shifting control is determined, a predetermined period from that time, even if the conditions for switching the even stepped stepless control from the speed change control is satisfied, the step-variable shifting control The stepped speed change control is continued without being switched to the stepless speed change control.

Is the uphill is determined by climbing determining means during execution of the step-variable shifting control, when the vehicle starts to climbing after being switched to the step-variable shifting control from the continuously variable transmission controlled in accordance with the driver's acceleration demand, Alternatively, it is a case where the continuously variable transmission control is switched to the continuously variable transmission control in response to the driver's acceleration request while the vehicle is climbing a slope. In any case, the driver is requested to accelerate the vehicle. is there. Therefore, the predetermined time period from being determined climbing the uphill determining means during execution of the step-variable shifting control, by the step-variable shifting control is continued, continuously variable from the step-variable shifting control is not along the intention of the driver Switching to control can be suppressed.

The switching condition for switching from stepped speed change control to stepless speed change control is that the variable that increases or decreases according to the accelerator operation in the vehicle is reduced to a predetermined value or less, and the speed change control means is determined to climb a slope by the climbing determination means. If not, the continuously variable transmission control is switched to the continuously variable transmission control according to the establishment of the switching condition, and the continuously variable transmission control is executed. If the climbing determination means determines the climbing, the switching condition is determined for a predetermined period from the determination. Regardless of whether or not the stepped speed change is established, the execution of the stepped speed change control may be continued without switching from the stepped speed change control to the stepless speed change control.

For example, a flat road (flat section) may be included in a short section in the middle of an uphill road. When the vehicle travels on such an uphill road, the driver may weaken the accelerator operation when the vehicle approaches the flat section from the uphill section and strengthen the accelerator operation when the vehicle approaches the uphill section again. .. The stepped shift control is executed in response to the driver's acceleration request in the uphill section, and the switching condition is satisfied when the vehicle approaches the flat section during the execution of the stepped shift control and the accelerator operation is weakened. when switched to the continuously-variable shifting control from the step-variable shifting control in response thereto, it immediately thereafter the vehicle when the accelerator operation is intensified by approaching the uphill section is switched again to the step-variable shifting control from the continuously variable shifting control become.

Predetermined period from climbing determination during the execution of the step-variable shifting control, by executing the step-variable shifting control is continued, if such a step-variable shifting control and the continuously variable control without along the intention of the driver Can be suppressed from being frequently switched. As a result, it is possible to suppress giving the driver a sense of discomfort due to frequent switching between stepped speed change control and stepless speed change control, and it is possible to improve drivability.

The predetermined period may be a period until the vehicle is determined not to be climbed by the climbing determination means, or after the vehicle is determined not to be climbed by the climbing determination means, the continuously variable transmission control is performed. It may be a period until the switching condition for switching to the step shift control (for example, the condition that the variable that increases or decreases according to the accelerator operation in the vehicle is reduced to a predetermined value) is satisfied. Further, the predetermined period may be a fixed or variable time.

According to the present invention, it is possible to suppress switching between stepless speed change control and stepped speed change control that is not intended by the driver, and it is possible to improve drivability.

It is a skeleton diagram which shows the structure of the drive system of a vehicle. It is a block diagram which shows the structure of the control system which concerns on one Embodiment of this invention. It is a figure which shows the relationship between a vehicle speed, a target engine speed, and a gear ratio. It is a figure which shows an example of the time change of the accelerator opening speed, the accelerator opening degree and the accelerator change amount. It is a figure which shows an example of the time change of an accelerator opening degree and a climbing determination flag.

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

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

The vehicle 1 is an automobile whose drive source is the engine 2.

The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) for injecting fuel into the intake air, an ignition plug for generating an electric discharge in the combustion chamber, and the like. Has been done. Further, the engine 2 is provided with a starter for starting the engine 2. The power of the engine 2 is transmitted to the differential gear 5 via the torque converter 3 and the belt-type continuously variable transmission (CVT) 4, and is transmitted from the differential gear 5 via the left and right drive shafts 6L and 6R. It is transmitted to the left and right drive wheels 7L and 7R, respectively.

The torque converter 3 includes a pump impeller 11, a turbine runner 12, and a lockup mechanism (lockup clutch) 13. The output shaft (E / G output shaft) of the engine 2 is connected to the pump impeller 11, and the pump impeller 11 is provided so as to be integrally rotatable around the same rotation axis as the E / G output shaft. ing. The turbine runner 12 is rotatably provided about the same rotation axis as the pump impeller 11. The lockup mechanism 13 is provided to directly connect / separate the pump impeller 11 and the turbine runner 12. When the lockup mechanism 13 is engaged (lockup on), the pump impeller 11 and the turbine runner 12 are directly connected, and when the lockup mechanism 13 is released (lockup off), the pump impeller 11 and the turbine runner 12 are directly connected. And are separated.

When the E / G output shaft is rotated in the lockup-off state, the pump impeller 11 rotates. When the pump impeller 11 rotates, an oil flow from the pump impeller 11 to the turbine runner 12 is generated. This flow of oil is received by the turbine runner 12, and the turbine runner 12 rotates. At this time, the amplification action of the torque converter 3 occurs, and the turbine runner 12 generates a power larger than the power (torque) of the E / G output shaft.

In the lockup-on state, when the E / G output shaft is rotated, the E / G output shaft, the pump impeller 11 and the turbine runner 12 are rotated together.

The continuously variable transmission 4 is a belt-type continuously variable transmission, and transmits the power input from the torque converter 3 to the differential gear 5. The continuously variable transmission 4 includes an input shaft (input shaft) 14, an output shaft (output shaft) 15, a belt transmission mechanism 16, and a forward / backward switching mechanism 17.

The input shaft 14 is connected to the turbine runner 12 of the torque converter 3 and is provided so as to be integrally rotatable around the same rotation axis as the turbine runner 12.

The output shaft 15 is arranged parallel to the input shaft 14. An output gear 18 is supported on the output shaft 15 so as not to rotate relative to each other.

The belt transmission mechanism 16 includes a primary shaft 21 and a secondary shaft 22. The primary shaft 21 and the secondary shaft 22 are arranged on the same axis as the input shaft 14 and the output shaft 15, respectively.

The belt transmission mechanism 16 has a configuration in which an endless belt 25 is wound around a primary pulley 23 supported by a primary shaft 21 and a secondary pulley 24 supported by a secondary shaft 22.

The primary pulley 23 is a movable sheave that is arranged so as to face the fixed sheave 31 fixed to the primary shaft 21 with the belt 25 sandwiched between the fixed sheave 31 and supported by the primary shaft 21 so as to be movable in the axial direction and not to rotate relative to each other. It has 32 and. A piston 33 fixed to the primary shaft 21 is provided on the side opposite to the fixed sheave 31 with respect to the movable sheave 32, and a piston chamber (oil chamber) 34 is formed between the movable sheave 32 and the piston 33. There is.

The secondary pulley 24 is arranged to face the fixed sheave 35 fixed to the secondary shaft 22 with the belt 25 sandwiched between the fixed sheave 35, and is supported by the secondary shaft 22 so as to be movable in the axial direction and not to rotate relative to each other. It is equipped with a movable sheave 36. A piston 37 fixed to the secondary shaft 22 is provided on the opposite side of the movable sheave 36 from the fixed sheave 35, and a piston chamber 38 is formed between the movable sheave 36 and the piston 37.

Although not shown, a bias spring for applying an initial pinching pressure (initial thrust) to the belt 25 is interposed between the movable sheave 36 and the piston 37. The elastic force of the bias spring urges the movable sheave 36 and the piston 37 in a direction in which they are separated from each other.

The forward / backward switching mechanism 17 is interposed between the input shaft 14 and the primary shaft 21 of the belt transmission mechanism 16. The forward / backward switching mechanism 17 includes a planetary gear mechanism 41, a clutch C1, and a clutch (brake) B1.

The planetary gear mechanism 41 includes a carrier 42, a sun gear 43, and a ring gear 44.

The carrier 42 is fitted onto the input shaft 14 so as to be relatively rotatable. The carrier 42 rotatably supports a plurality of pinion gears 45. The plurality of pinion gears 45 are arranged on the circumference.

The sun gear 43 is supported by the input shaft 14 so as not to rotate relative to each other, and is arranged in a space surrounded by a plurality of pinion gears 45. The gear teeth of the sun gear 43 mesh with the gear teeth of each pinion gear 45.

The ring gear 44 is provided so that its rotation axis coincides with the axis of the primary shaft 21. The primary shaft 21 of the belt transmission mechanism 16 is connected to the ring gear 44. The gear teeth of the ring gear 44 are formed so as to collectively surround the plurality of pinion gears 45, and mesh with the gear teeth of each pinion gear 45.

The clutch C1 is switched between an engaged state (on) in which the carrier 42 and the sun gear 43 are directly connected (coupled so as to be integrally rotatable) and an released state (off) in which the direct connection is released.

The clutch B1 is provided between the carrier 42 and the transmission case accommodating the torque converter 3 and the continuously variable transmission 4, and allows the carrier 42 to rotate in an engaged state (on) in which the carrier 42 is braked by flood control. It can be switched to the released state (off).

A shift lever (select lever) is arranged in the vehicle interior of the vehicle 1 at a position where the driver can operate the vehicle. In the movable range of the shift lever, for example, a P (parking) position, an R (reverse) position, an N (neutral) position, and a D (drive) position are provided in this order in a row.

When the shift lever is in the P position, both the clutch C1 and the clutch B1 are released, and the parking lock gear (not shown) is fixed, which is one of the shift ranges of the continuously variable transmission 4. The P range is configured. Further, when the shift lever is in the N position, both the clutch C1 and the clutch B1 are released and the parking lock gear is not fixed, so that the N range, which is one of the shift ranges of the continuously variable transmission 4, is set. It is composed. When both the clutch C1 and the clutch B1 are released, the input shaft 14 and the sun gear 43 idle, and the power of the engine 2 is not transmitted to the drive wheels 7L and 7R.

When the shift lever is in the D position, the clutch B1 is engaged and the clutch C1 is released to form a forward range, which is one of the shift ranges of the continuously variable transmission 4. In the forward range, when the power of the engine 2 is input to the input shaft 14, the sun gear 43 rotates integrally with the input shaft 14 while the carrier 42 is stationary. Therefore, the rotation of the sun gear 43 is transmitted to the ring gear 44 in reverse and decelerated. As a result, the ring gear 44 rotates, and the primary shaft 21 and the primary pulley 23 of the belt transmission mechanism 16 rotate integrally with the ring gear 44. The rotation of the primary pulley 23 is transmitted to the secondary pulley 24 via the belt 25 to rotate the secondary pulley 24 and the secondary shaft 22. Then, the output shaft 15 and the output gear 18 rotate integrally with the secondary shaft 22. The output gear 18 meshes with the differential gear 5 (the input gear of the differential gear 5). When the output gear 18 rotates, the drive shafts 6L and 6R extending to the left and right from the differential gear 5 rotate, and the drive wheels 7L and 7R rotate to advance the vehicle 1.

When the shift lever is in the D position, shift control is performed to automatically shift the gear ratio.

When the shift lever is in the R position, the clutch B1 is released and the clutch C1 is engaged to form the R range, which is one of the shift ranges of the continuously variable transmission 4. In the R range, when the power of the engine 2 is input to the input shaft 14, the carrier 42 and the sun gear 43 rotate integrally with the input shaft 14. Therefore, the rotation of the sun gear 43 is transmitted to the ring gear 44 without reversing the rotation direction. As a result, the ring gear 44 rotates, and the primary shaft 21 and the primary pulley 23 of the belt transmission mechanism 16 rotate integrally with the ring gear 44. The rotation of the primary pulley 23 is transmitted to the secondary pulley 24 via the belt 25 to rotate the secondary pulley 24 and the secondary shaft 22. Then, the output shaft 15 and the output gear 18 rotate integrally with the secondary shaft 22. When the output gear 18 rotates, the drive shafts 6L and 6R extending to the left and right from the differential gear 5 rotate, and the drive wheels 7L and 7R rotate, so that the vehicle 1 moves backward.

<Vehicle control system>
FIG. 2 is a block diagram showing a configuration of a control system of the vehicle 1.

The vehicle 1 is provided with an ECU (Electronic Control Unit) 51 having a configuration including a microcomputer (microcontroller unit). The microcomputer has, for example, a CPU, ROM and RAM, a data flash (flash memory), and the like. FIG. 1 shows only one ECU 51 for controlling a drive transmission system including an engine 2, a torque converter 3, and a continuously variable transmission 4, but the vehicle 1 has an ECU 51 for controlling each part. A plurality of ECUs having the same configuration as the above are mounted. A plurality of ECUs including the ECU 51 are connected so as to enable two-way communication by a CAN (Controller Area Network) communication protocol.

Various sensors required for control are connected to the ECU 51. As an example, the ECU 51 detects, for example, an accelerator sensor 61 that outputs a detection signal according to the amount of operation of the accelerator pedal operated by the driver, and a pulse signal synchronized with the rotation of the engine 2 (rotation of the crankshaft). An engine rotation sensor 62 that outputs a signal and a throttle opening sensor 63 that outputs a detection signal according to the opening degree (throttle opening degree) of the electronic throttle valve of the engine 2 are connected.

Further, the ECU 51 detects a pulse signal synchronized with the rotation of the primary shaft 21 of the stepless transmission 4 and a turbine rotation sensor 64 that outputs a pulse signal synchronized with the rotation of the turbine runner 12 of the torque converter 3 as a detection signal. The primary rotation sensor 65 that outputs as a detection signal, the secondary rotation sensor 66 that outputs a pulse signal synchronized with the rotation of the secondary shaft 22 of the stepless transmission 4 as a detection signal, and detection according to the P, R, N, D positions of the shift lever. The shift position sensor 67 that outputs a signal, the vehicle speed sensor 68 that outputs a pulse signal synchronized with the rotation of the rotating body that rotates with the running of the vehicle 1 as a detection signal, and the signal corresponding to the displacement of the weight are used as the acceleration of the vehicle 1. A G sensor 69 that outputs as a corresponding detection signal is connected.

The ECU 51 includes an engine control logic for controlling the engine 2 and a CVT control logic for controlling the torque converter 3 and the continuously variable transmission 4.

In the engine control logic, from each detection signal of the accelerator sensor 61, the engine rotation sensor 62, and the throttle opening sensor 63, the accelerator opening (the ratio of the amount of depression to the maximum amount of depression of the accelerator pedal, that is, when the accelerator pedal is not depressed) Is 0%, and the percentage when the accelerator pedal is depressed to the maximum is 100%), the engine speed (the speed of the engine 2), and the throttle opening degree are acquired. Further, in the engine control logic, information is acquired from the CVT control logic and other ECUs. Then, based on the information acquired from various sensors by the engine control logic, the information input from the CVT control logic and other ECUs, and the like, the engine 2 is provided for starting, stopping, and adjusting the output of the engine 2. The electronic throttle valve, injector, spark plug, etc. are controlled.

In the CVT control logic, from each detection signal of the turbine rotation sensor 64, the primary rotation sensor 65, and the secondary rotation sensor 66, the turbine rotation speed (the rotation speed of the turbine runner 12), the primary rotation speed (the rotation speed of the primary shaft 21), and the secondary The number of rotations (the number of rotations of the secondary shaft 22) is acquired. Further, the position of the shift lever and the vehicle speed and acceleration of the vehicle 1 are acquired from the detection signals of the shift position sensor 67, the vehicle speed sensor 68, and the G sensor 69. Further, in the CVT control logic, information is acquired from the engine control logic and other ECUs. Then, the continuously variable transmission 4 is used for shifting control of the continuously variable transmission 4 based on information acquired from various sensors, engine control logic, information input from other ECUs, etc. by the CVT control logic. Various valves included in the hydraulic circuit for supplying hydraulic pressure to each part of the above are controlled.

<Shift control>
FIG. 3 is a diagram showing the relationship between the vehicle speed, the target engine speed, and the gear ratio.

When the shift range of the continuously variable transmission 4 is the forward range and the shift lever is in the D position, the ECU 51 executes shift control for automatically shifting the gear ratio of the continuously variable transmission 4. In this shift control, stepless shift control and stepped shift control (linear shift control) are selectively executed. In the continuously variable transmission control, the gear ratio of the continuously variable transmission 4 is changed steplessly. In the stepped speed change control, a plurality of shift stages are set, and the gear ratio of the continuously variable transmission 4 is gradually changed between the plurality of shift stages.

In the region where the accelerator opening is small, continuously variable transmission control is executed. A shift diagram for continuously variable transmission control is stored in the memory of the ECU 51. This shift line diagram defines the relationship between the accelerator opening (AP) and the vehicle speed and the target engine speed, as shown by a broken line in FIG. In the continuously variable transmission control, the target engine speed is set according to the accelerator opening and the vehicle speed from the shift diagram, and the engine speed (the speed input from the torque converter 3 to the input shaft 14 of the continuously variable transmission 4). ) Is changed so that it matches the target engine speed.

As a result, the gear ratio can be continuously changed so that the engine speed is included in the highly efficient rotation range according to the changes in the accelerator opening and the vehicle speed, taking advantage of the continuously variable transmission control. It is possible to realize fuel-efficient driving.

In the stepped speed change control, for example, a gear ratio corresponding to each of the 1st to 7th speed gears in an AT (Automatic Transmission) is set. A shift line (not shown) for stepped shift control is stored in the memory of the ECU 51. This shift diagram defines the accelerator opening and the vehicle speed, which are the conditions for shifting between each shift stage. The shift line diagram for stepped shift control includes an upshift diagram that defines the conditions for upshifting from N speed (N: natural number) to N + 1 speed, and a downshift from N + 1 speed to N speed. It may include a downshift diagram that defines the conditions of. In stepped shifting control, a target shifting stage is set according to the accelerator opening and vehicle speed from the shifting line diagram. The gear is changed to the gear ratio of the gear.

As a result, it is possible to obtain a linear acceleration response or a feeling of acceleration according to the accelerator operation.

<Stepless speed change control → Stepped speed change control>
FIG. 4 is a diagram showing an example of time changes in the accelerator opening speed, the accelerator opening degree, and the accelerator change amount.

During the execution of the continuously variable transmission control, the accelerator opening is acquired by the ECU 51 at a constant cycle, and each time the accelerator opening is acquired, the accelerator opening speed, which is the amount of change in the accelerator opening per unit time, is acquired. To. The accelerator opening speed can be obtained, for example, by the time derivative calculation of the accelerator opening.

When the accelerator pedal is depressed (time T11) and the accelerator opening speed rises to the first threshold value (time T12), the accelerator opening at that time becomes a reference value (operation start opening) in the memory (RAM) of the ECU 51. It will be saved. After that, each time the accelerator opening degree is acquired by the ECU 51, the accelerator change amount, which is the difference between the accelerator opening degree and the reference value, is acquired.

Then, when the conditions that the accelerator opening speed is equal to or higher than the second threshold value larger than the first threshold value, the accelerator opening degree is equal to or higher than the third threshold value, and the accelerator change amount is equal to or higher than the fourth threshold value are satisfied (time T13). ), The ECU 51 switches from the stepless speed change control to the stepped speed change control, and the stepped speed change control is executed.

<Stepped speed change control → Stepless speed change control>
FIG. 5 is a diagram showing an example of time changes of the accelerator opening degree and the climbing determination flag.

Even during the execution of the stepped speed change control, the accelerator 51 acquires the accelerator opening degree at a constant cycle.

Further, while the vehicle 1 is traveling, the ECU 51 repeatedly determines whether or not the vehicle 1 is climbing a slope.

The acceleration acquired from the detection signal of the G sensor 69 includes an acceleration component due to a change in vehicle speed and an acceleration component due to the slope of the road surface on which the vehicle 1 is traveling. On the other hand, the acceleration obtained by differentiating the vehicle speed acquired from the output signal of the vehicle speed sensor 68 is only the acceleration component due to the change in the vehicle speed. Therefore, by obtaining the difference between the acceleration acquired from the detection signal of the G sensor 69 and the differential value of the vehicle speed, the acceleration component due to the road surface gradient can be obtained. Therefore, the road surface gradient can be estimated based on the acceleration component. it can. Then, when the slope is uphill, the value of the slope is positive, and when the slope is downhill, the value of the slope is negative. For example, if the road surface slope is a certain positive value or more, the vehicle 1 climbs a slope. It can be determined that the vehicle 1 is inside, and if the road surface gradient is less than the certain value, it can be determined that the vehicle 1 is not climbing a slope.

When the stepped speed change control is being executed and the vehicle 1 is not climbing a slope, the ECU 51 repeatedly determines whether or not the switching condition for switching from the stepped speed change control to the stepless speed change control is satisfied. The switching condition is, for example, a condition that the accelerator opening degree has decreased to a predetermined value (for example, 0%). When the switching condition is satisfied while the vehicle 1 is not climbing a slope and the climbing determination flag is reset to 0, the ECU 51 switches from the stepped speed change control to the stepless speed change control, and the stepless speed change control is executed. To.

For example, when the vehicle 1 approaches the uphill road during the execution of the stepped speed change control, the ECU 51 determines that the vehicle 1 is climbing a slope, and 1 is set in the uphill determination flag provided in the RAM of the ECU 51. (Time T21).

The ECU 51 determines the continuation of the stepped shifting control according to the climbing determination during the stepped shifting control. In other words, in response to the climbing determination during the stepped speed change control, the ECU 51 is prohibited from switching from the stepped speed change control to the stepless speed change control. While it is decided to continue the stepped speed change control, even if the switching condition is satisfied due to the accelerator operation being weakened (stopped) and the accelerator opening dropping to a predetermined value, the stepped speed change control is performed. Cannot switch to continuously variable transmission control.

The decision to continue the stepped speed change control (prohibition of switching from stepped speed change control to stepless speed change control) is determined by upshifting from N speed to N + 1 speed and from N + 1 speed to N by stepped speed control. It does not prohibit downshifting to a speed speed, and even while the decision to continue stepped speed change control is being made, a target speed change is set according to the accelerator opening and vehicle speed, and the speed change ratio changes to the speed change ratio of the target speed change. Will be done.

After that, when the vehicle 1 passes through the uphill road and the ECU 51 determines that the vehicle 1 is not uphill (time T22), the uphill determination flag is reset to 0 and the determination to continue the stepped speed change control is canceled. Will be done. That is, while the climbing determination flag is set to 1, the continuation of the stepped shifting control is determined, and when the climbing determination flag is reset to 0, the determination to continue the stepped shifting control is released.

After the decision to continue the stepped speed change control is released, when the accelerator operation is weakened and the switching condition is satisfied by reducing the accelerator opening to a predetermined value, the ECU 51 determines the stepped speed change according to the establishment. The control is switched to the continuously variable transmission control, and the continuously variable transmission control is executed (time T23).

<Effect>
As described above, when the climbing of the vehicle 1 is determined during the execution of the stepped speed change control, there is no stepped speed change control for a predetermined period from that time until it is determined that the vehicle 1 is not climbing the slope. Even if the switching condition for switching to the continuously variable transmission is satisfied, the continuously variable transmission control cannot be switched to the continuously variable transmission control, and the continuously variable transmission control is continued.

The climbing of the vehicle 1 is determined during the execution of the stepped speed change control after the vehicle 1 starts climbing after switching from the stepless speed change control to the stepped speed change control in response to the accelerator operation according to the driver's acceleration request. In any case, the driver is asked to switch from continuously variable transmission control to stepped transmission control in response to the accelerator operation requested by the driver while climbing the slope of the vehicle 1. There is a demand to accelerate vehicle 1. Therefore, the stepped shift control is continued for a predetermined period after the climbing of the vehicle 1 is determined during the execution of the stepped shift control, so that the stepped shift control is changed to the stepless shift control that does not meet the driver's intention. Switching to can be suppressed.

For example, a flat road (flat section) may be included in a short section in the middle of an uphill road. When the vehicle 1 travels on such an uphill road, the driver weakens the accelerator operation when the vehicle 1 approaches the uphill section to the flat section, and strengthens the accelerator operation when the vehicle 1 approaches the uphill section again. Sometimes. The switching condition is satisfied when the vehicle 1 approaches the flat section and the accelerator operation is weakened during the execution of the stepped speed change control, and as shown by the broken line in FIG. 5, the stepped condition is satisfied according to the establishment of the switching condition. When the shift control is switched to the continuously variable transmission control (time T31), immediately after that, when the vehicle 1 approaches the uphill section and the accelerator operation is strengthened, the continuously variable transmission control is switched to the continuously variable transmission control again. (Time T32).

By continuing the execution of the stepped speed change control for a predetermined period from the climbing determination during the stepped speed change control execution, in such a case, as shown by the solid line in FIG. 5, without following the driver's intention. It is possible to prevent frequent switching between stepped speed change control and stepless speed change control. As a result, it is possible to suppress giving the driver a sense of discomfort due to frequent switching between stepped speed change control and stepless speed change control, and it is possible to improve drivability.

Further, in order to switch from the continuously variable transmission control to the stepped transmission control, the accelerator opening degree that increases or decreases by the accelerator operation and the accelerator opening speed that is the amount of change in the accelerator opening degree per unit time are acquired. When the accelerator is operated during the execution of the continuously variable transmission control, the accelerator opening at the time when the accelerator opening speed rises to the first threshold value is used as a reference value, and the accelerator opening and the reference value acquired thereafter are set. The amount of change in the accelerator, which is the difference, is obtained. Then, when the conditions that the accelerator opening speed is equal to or higher than the second threshold value larger than the first threshold value, the accelerator opening degree is equal to or higher than the third threshold value, and the accelerator change amount is equal to or higher than the fourth threshold value are satisfied, there is no step. It is possible to switch from shift control to stepped shift control.

Not only when the accelerator is operated according to the driver's acceleration request, but also when the vehicle 1 crosses a step on the road surface and the accelerator is operated without the driver's intention, the accelerator opening speed becomes equal to or higher than the second threshold value. , The operation amount of the accelerator operation may be equal to or larger than the third threshold value. When the driver requests the acceleration of the vehicle 1, the accelerator opening is increased by continuing the accelerator operation until the driver is satisfied with the acceleration. On the other hand, the driver's unintended accelerator operation, such as when the vehicle 1 crosses a step on the road surface, does not continue for a long time, and is immediately stopped (released) even if the accelerator operation is momentarily performed. Therefore, when the fourth threshold value is appropriately set, the condition that the accelerator opening speed is equal to or higher than the second threshold value and the accelerator opening degree is equal to or higher than the third threshold value is satisfied, and the reference value of the accelerator opening degree is satisfied. If the condition that the accelerator change amount, which is the amount of increase in the above, is further satisfied, it can be determined that the accelerator operation has been performed according to the driver's acceleration request, and the accelerator change amount is said to be the fourth threshold value or more. If the condition is not further satisfied, it can be determined that the accelerator operation was not intended by the driver.

Therefore, depending on whether the accelerator operation during the continuously variable transmission control is an accelerator operation due to the driver's acceleration request or an accelerator operation not intended by the driver, the continuously variable transmission control should be appropriately switched to the continuously variable transmission control. Can be done. Therefore, it is possible to prevent the driver from erroneously determining that the unintended accelerator operation is due to the acceleration request and switching from the continuously variable transmission control to the continuously variable transmission control according to the accelerator operation. As a result, it is possible to suppress giving the driver a sense of discomfort due to switching from continuously variable transmission control to stepped transmission control that the driver does not plan.

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

For example, in the shift control for shifting the gear ratio of the continuously variable transmission 4, the continuously variable transmission control and the stepped shift control are selectively executed. Stepped gear shifting control is a form of accelerated gear shifting control, and in gear shifting control, continuously variable transmission control and accelerated gear shifting control other than stepped gear shifting control may be selectively executed. Acceleration shift control (acceleration shift mode) is shift control in which control rules are set so that an acceleration feeling can be obtained according to the driver's acceleration request. It includes control that limits the corresponding increase in engine speed and shifts the gear ratio so that the engine speed increases proportionally with the increase in vehicle speed.

Further, in the above-described embodiment, the predetermined period is a period until it is determined that the vehicle 1 is not climbing a slope, that is, a period in which 1 is set in the climbing determination flag. Not limited to this, the predetermined period may be a period from when it is determined that the vehicle 1 is not climbing a slope until the switching condition for switching from the acceleration shift control to the continuously variable transmission control is satisfied, or it may be fixed or variable. It may be the time set to.

Sensors other than the various sensors 61 to 69 shown in FIG. 2 may be connected to the ECU 51, or some of the sensors 61 to 69 may be connected to other ECUs.

Further, although it is assumed that the engine control logic and the CVT control logic are incorporated in one ECU 51, the engine control logic and the CVT control logic may be provided as separate ECUs.

Although the continuously variable transmission 4 has been taken up, the control device according to the present invention can also be used for a power split type continuously variable transmission. The power split type stepless transmission is equipped with a belt-type stepless transmission mechanism that shifts power steplessly by changing the gear ratio and a constant transmission mechanism that shifts power at a constant gear ratio, and power of a drive source. Is a transmission that can be transmitted by dividing it into two systems.

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

1: Vehicle 2: Engine (drive source)
4: Continuously variable transmission 51: ECU (control device, climbing determination means, shift control means)

Claims (1)

A control device used in a vehicle equipped with a continuously variable transmission capable of steplessly shifting the power from a drive source to control the continuously variable transmission.
A climbing determination means for determining whether or not the vehicle is climbing,
Wherein the step-variable shifting control to stepwise shift in different control law and the continuously variable transmission controls the gear ratio of the continuously variable transmission and control the continuously variable transmission to shift the gear ratio of the continuously variable transmission with steplessly Including shift control means to be selectively executed
When the climbing determination means determines climbing during the execution of the stepped speed change control, the speed change control means controls the continuously variable transmission by continuing the execution of the stepped speed change control for a predetermined period from the determination. apparatus.

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