JP6629028B2 - 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, a continuously variable transmission (CVT) is widely known.

  The CVT has a configuration in which a belt is wound around a primary pulley and a secondary pulley. In the CVT, the gear ratio can be continuously and continuously changed by changing the groove width of the primary pulley and the secondary pulley continuously and changing the winding diameter of the belt around the primary pulley and the secondary pulley. it can.

  In the CVT, the groove width of each of the primary pulley and the secondary pulley can be changed in a stepwise manner. In addition to the stepless speed change mode in which the speed ratio is continuously changed steplessly, the speed ratio can be changed stepwise. Can be provided. By providing the stepped shift mode, a multi-stage shift feeling can be realized even in a vehicle equipped with a continuously variable transmission. The stepped transmission mode includes a stepped automatic transmission mode such as AT (Automatic Transmission), which automatically switches to a gear ratio according to the traveling state of the vehicle, and an MT (Manual Transmission). , A manual shift mode (manual mode) in which the gear ratio is changed by a driver's shift operation.

  When the CVT has a continuously variable transmission mode, a stepped automatic transmission mode, and a manual transmission mode, for example, an S position is provided on the right side of a D position (a position corresponding to a forward range) of a shift lever, and a front side of the S position and A "+" position (upshift position) and a "-" position (downshift position) are provided on the rear side, respectively. When the shift lever is at the D position, the continuously variable transmission mode is set. When the shift lever is operated from the D position to the S position, the mode is switched from the continuously variable transmission mode to the stepped automatic transmission mode. When the shift lever is operated from the S position to the “+” position or the “−” position, the mode is switched from the stepped automatic transmission mode to the manual transmission mode. In the manual shift mode, when the shift lever is operated once from the S position to the “+” position, the gear ratio is changed to a gear ratio one step higher, and the shift lever is operated once from the S position to the “−” position. Then, the gear ratio is changed to a gear ratio one step lower.

JP-A-8-82354

  In the manual shift mode, the change of the gear ratio by the driver's shift operation is prioritized. Even if the gear ratio is not suitable for the running state of the vehicle, the gear ratio is not changed in principle. However, when the engine speed exceeds the upper limit or the lower limit, such as when the CVT structure or reliability is adversely affected, the gear ratio is automatically changed.

  For example, in the manual shift mode, when the vehicle is accelerated during traveling at the second speed (a speed ratio corresponding to the second speed in the AT), when the vehicle speed reaches 70 km / h, the second speed to the third speed are established. Automatically shifted up. In order to prevent shifting hunting (frequent switching of the gear ratio), hysteresis is provided for the downshift, and when the vehicle speed decreases to 65 km / h, the downshift from the third gear to the second gear is permitted. .

  During sports driving on a circuit or the like, the driver may want to perform rapid deceleration using both the foot brake and the engine brake, or may wish to have an early downshift in preparation for re-acceleration after deceleration. During traveling in the third gear, downshifting to the second gear is not permitted until the vehicle speed drops to 65 km / h. Therefore, even if the shift operation is performed at a timing desired by the driver, the downshift is not performed at that timing, and the operability is poor.

  An object of the present invention is to provide a control device for a continuously variable transmission that can improve deceleration performance and operability during sports running in a manual shift mode.

  In order to achieve the above object, a control device for a continuously variable transmission according to the present invention is used for a vehicle equipped with a continuously variable transmission that changes and outputs a driving force in a stepless manner. A control device for controlling an automatic transmission mode in which a gear ratio is changed without a shift operation and a manual transmission mode in which a gear ratio is changed in response to a shift operation between a plurality of fixed gear ratios set in steps. And a mode setting means for selectively setting the vehicle speed of the vehicle in the manual shift mode, and when the vehicle speed is equal to or higher than the downshift permitting vehicle speed, from the current fixed gear ratio to the fixed gear ratio one step lower than the current fixed gear ratio. Downshift permission means for permitting a change from the current fixed gear ratio to a fixed gear ratio one step lower when the vehicle speed is lower than the downshift permission vehicle speed, and reducing the vehicle speed in the manual gearshift mode. Get speed, And a correcting means for correcting to increase the downshift permit vehicle speed at a large width as the reduced speed is greater.

  According to this configuration, the automatic shift mode and the manual shift mode are selectively set. In the automatic shift mode, the gear ratio is automatically changed without depending on the shift operation. In the manual transmission mode, the transmission ratio is changed in response to a shift operation among a plurality of fixed transmission ratios set in stages.

  In the manual transmission mode, when the vehicle speed is lower than the downshift permission vehicle speed, if a shift operation for instructing a downshift is performed, the vehicle is downshifted to a fixed gear ratio one step lower than the current fixed gear ratio. On the other hand, if the vehicle speed is equal to or higher than the downshift permission vehicle speed, the downshift from the current fixed gear ratio to the fixed gear ratio one step lower than the current fixed gear ratio is prohibited even if the shift operation for instructing the downshift is performed.

  During sport running, the driver may want to downshift during running at a vehicle speed equal to or higher than the downshift permission vehicle speed. A situation in which the driver desires a downshift is a situation in which the vehicle is approaching a corner of a circuit while decelerating, and the deceleration is often greater than when decelerating in city driving.

  Therefore, in the manual shift mode, the deceleration of the vehicle is acquired, and a correction is made to increase the downshift permission vehicle speed by a larger width as the deceleration is larger. Accordingly, when the driver performs a shift operation for instructing a downshift, it is possible to suppress the downshift from being prohibited because the vehicle speed is equal to or higher than the downshift permission vehicle speed, and the driver can perform the downshift at a desired timing. A shift can be achieved.

  Therefore, the deceleration performance and the operability during sports running in the manual shift mode are improved.

  The correction means adds the corrected vehicle speed to the downshift permission vehicle speed by using the multiplied value of the deceleration of the vehicle and the shift time required for downshifting from the current fixed speed ratio to the fixed speed ratio one step lower as the corrected vehicle speed. Alternatively, a correction for increasing the downshift permission vehicle speed may be performed.

  Further, the correction means adds a predetermined additional time to the shift time, adds the corrected vehicle speed to the downshift permission vehicle speed by using the multiplied value of the added value and the deceleration of the vehicle as the correction vehicle speed, thereby obtaining the downshift permission vehicle speed. May be corrected.

  The control device may be configured to include an automatic upshift means for changing the gear ratio from the current fixed gear ratio to a fixed gear ratio one step higher when the vehicle speed of the vehicle is equal to or higher than a predetermined automatic upshift vehicle speed. .

  In this case, when the vehicle speed of the vehicle is lower than the downshift permission vehicle speed after the correction by the correction unit and the vehicle speed is equal to or higher than the automatic upshift vehicle speed, the control device changes the speed ratio by the automatic upshift unit. A configuration including an upshift prohibiting means for prohibiting the shift may be employed.

  As a result, it is possible to suppress an upshift because the vehicle speed is equal to or higher than the automatic upshift vehicle speed immediately after the downshift in response to the shift operation by the driver, and to maintain a fixed gear ratio desired by the driver. it can.

  According to the present invention, it is possible to improve the deceleration performance and the operability during sports running in the manual shift mode.

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 flowchart which shows the flow of a downshift process. An example of the presence / absence of the accelerator operation (on / off), the presence / absence of the brake operation (on / off), the master cylinder pressure, the engine speed, the vehicle speed, the acceleration, and the state of the automatic upshift inhibition flag at the time of the downshift are shown. It is a graph. 5 is a graph showing a relationship between a vehicle speed and an engine speed.

  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 continuously variable transmission (CVT) 4. The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) for injecting fuel into intake air, and a spark plug for generating electric discharge in the combustion chamber. Have been. The engine 2 is provided with a starter for starting the engine.

  The vehicle 1 includes a plurality of ECUs (electronic control units) each including a CPU and a memory such as a ROM and a RAM. The ECU includes an engine ECU 11, a CVT ECU 12, and a brake ECU 13. The plurality of ECUs are connected so as to be capable of bidirectional communication using a CAN (Controller Area Network) communication protocol.

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

  The accelerator sensor 21 inputs a signal corresponding to an operation amount of an accelerator pedal (not shown) to the engine ECU 11. Based on the signal input from the accelerator sensor 21, the engine ECU 11 sets the ratio of the operation amount to the maximum operation amount of the accelerator pedal, that is, 0% when the accelerator pedal is not depressed, and 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 inputs a pulse signal synchronized with the rotation of the engine 2 (the rotation of the crankshaft) to the engine ECU 11. The engine ECU 11 converts the frequency of the pulse signal input from the engine speed sensor 22 into the engine speed (engine speed).

  The engine ECU 11 starts and stops the engine 2 and adjusts the output based on numerical values obtained from signals input from various sensors and various information input from other ECUs. Controls throttle valves, injectors, spark plugs, etc.

  The CVT ECU 12 is connected with a primary rotation speed sensor 23, a secondary rotation speed sensor 24, a shift position sensor 25, and the like.

  The primary rotation speed sensor 23 inputs a pulse signal synchronized with the rotation of the primary shaft 51 (see FIG. 2) of the continuously variable transmission 4 to the CVT ECU 12, for example. The CVT ECU 12 converts the frequency of the pulse signal input from the primary rotation speed sensor 23 into the rotation speed of the primary shaft 51 (primary rotation speed). Further, the CVT ECU 12 calculates the rotation speed (turbine rotation speed) of the turbine runner 32 (see FIG. 2) of the torque converter 3 by multiplying the primary rotation speed by the speed ratio of the forward / reverse switching mechanism 44 (see FIG. 2). .

  Since the input shaft 41 of the continuously variable transmission 4 (see FIG. 2) is directly connected to the turbine runner 32 of the torque converter 3, the turbine speed is the same as the speed of the input shaft 41.

  The secondary speed sensor 24 inputs a pulse signal synchronized with the rotation of the secondary shaft 52 (see FIG. 2) of the continuously variable transmission 4 to the CVT ECU 12, for example. The CVT ECU 12 converts the frequency of the pulse signal input from the secondary rotation speed sensor 24 into the rotation speed (secondary rotation speed) of the secondary shaft 52 (see FIG. 2).

  The shift position sensor 25 inputs a signal corresponding to the position of the shift lever to the CVT ECU 12, for example. The position of the shift lever will be described later.

  The CVT ECU 12 controls each part of the continuously variable transmission 4 to control the speed ratio of the continuously variable transmission 4 based on numerical values obtained from signals input from various sensors and various information input from other ECUs. It controls various valves (not shown) included in a hydraulic circuit 26 for supplying hydraulic pressure to the motor.

  A brake pressure sensor 27, a vehicle speed sensor 28, and the like are connected to the brake ECU 13.

  In the vehicle 1, when the brake pedal is depressed, the depression force input to the brake pedal is transmitted to the brake booster. The pedaling force transmitted to the brake booster is amplified (boosted) by the negative pressure of the brake booster, and is input from the brake booster to the brake master cylinder. In the brake master cylinder, a hydraulic pressure is generated according to the force input from the brake booster. The hydraulic pressure generated by the brake master cylinder is transmitted to the brake actuator 29. The hydraulic pressure is distributed to the wheel cylinders of the brakes provided on each wheel by the function of the brake actuator 29, and the braking force is applied to the wheels from each brake by the hydraulic pressure.

  The brake pressure sensor 27 detects the generated hydraulic pressure (master cylinder pressure) of the brake master cylinder, and inputs a detection signal corresponding to the master cylinder pressure to the brake ECU 13.

  The vehicle speed sensor 28 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 a predetermined angle, a pulse signal is output from the electromagnetic pickup, and the pulse signal is input to the brake ECU 13. Since the frequency of the pulse signal corresponds to the vehicle speed, the brake ECU 13 can convert the frequency of the pulse signal input from the vehicle speed sensor 28 into the vehicle speed and acquire it.

  The brake ECU 13 controls the brake actuator 29 and the like based on the master cylinder pressure, the vehicle speed of the vehicle 1, various information input from other ECUs, and the like, and controls the vehicle 1 in a state where the posture of the vehicle 1 is stably maintained. The braking force applied from each brake to the wheels is controlled so that the brake is applied.

<Drive system configuration>
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 with the lock-up clutch 33 released, the pump impeller 31 rotates. When the pump impeller 31 rotates, oil flows from the pump impeller 31 toward 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.

  With the lock-up clutch 33 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 continuously variable transmission 4. The oil pump 5 is a mechanical oil pump, and the pump shaft is arranged so that the rotation axis thereof coincides with that of the pump impeller 31, and is connected to the pump impeller 31 so as not to rotate relatively. 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 is discharged from the oil pump 5.

  The continuously variable transmission 4 transmits power input from the torque converter 3 to the differential gear 6. The continuously variable transmission 4 includes an input shaft 41, an output shaft 42, a belt transmission mechanism 43, and a forward / reverse switching 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 arranged parallel to the input shaft 41. An output gear 45 is supported by the output shaft 42 so as not to rotate relatively.

  The belt transmission mechanism 43 includes a primary shaft 51 and a secondary shaft 52. The primary shaft 51 and the secondary shaft 52 are arranged so as to be on the same axis as the input shaft 41 and the output shaft 42, respectively, and to at least partially overlap in a direction orthogonal to the axial direction.

  The belt transmission mechanism 43 has a configuration in which an endless belt 55 is wound around a primary pulley 53 supported on a primary shaft 51 and a secondary pulley 54 supported on a secondary shaft 52.

  The primary pulley 53 is opposed to a fixed sheave 61 fixed to the primary shaft 51 with a belt 55 interposed therebetween, and a movable sheave supported on the primary shaft 51 so as to be movable in its axial direction and relatively non-rotatable. 62. A piston 63 fixed to the primary shaft 51 is provided on a side opposite to the fixed sheave 61 with respect to the movable sheave 62, and a piston chamber 64 is formed between the movable sheave 62 and the piston 63.

  The secondary pulley 54 is opposed to a fixed sheave 65 fixed to the secondary shaft 52 with a belt 55 interposed between the fixed sheave 65 and supported by the secondary shaft 52 so as to be movable in its axial direction and relatively non-rotatable. And a movable sheave 66. A piston 67 fixed to the secondary shaft 52 is provided on the opposite side of the movable sheave 66 from the fixed sheave 65, and a piston chamber 68 is formed between the movable sheave 66 and the piston 67.

  In the continuously variable transmission 4, the hydraulic pressures supplied to the piston chamber 64 of the primary pulley 53 and the piston chamber 68 of the secondary pulley 54 are controlled, and the groove widths of the primary pulley 53 and the secondary pulley 54 are changed. The gear ratio is continuously and continuously changed.

  Specifically, when the gear ratio is reduced, the hydraulic pressure supplied to the piston chamber 64 of the primary pulley 53 is increased. As a result, the movable sheave 62 of the primary pulley 53 moves toward the fixed sheave 61, and the distance (groove width) between the fixed sheave 61 and the movable sheave 62 is reduced. Along with this, the winding diameter of the belt 55 around the primary pulley 53 increases, and the distance (groove width) between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 increases. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 decreases, and the speed ratio decreases.

  When the speed ratio is increased, the hydraulic pressure supplied to the piston chamber 64 of the primary pulley 53 is reduced. As a result, the thrust of the secondary pulley 54 on the belt 55 becomes larger than the thrust of the primary pulley 53 on the belt 55, the distance between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 becomes smaller, and the fixed sheave 61 and the movable sheave The distance from the gap 62 increases. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 increases, and the gear ratio increases.

  On the other hand, the thrust of the primary pulley 53 and the secondary pulley 54 needs to be large enough to prevent slippage between the primary pulley 53 and the secondary pulley 54 and the belt 55. Therefore, the hydraulic pressure supplied to the piston chamber 64 of the primary pulley 53 and the hydraulic pressure supplied to the piston chamber 68 of the secondary pulley 54 are controlled so that a thrust corresponding to the magnitude of the torque input to the input shaft 41 is obtained. You.

  The forward / reverse switching mechanism 44 is interposed between the input shaft 41 and the primary shaft 51 of the belt transmission mechanism 43. The forward / reverse switching mechanism 44 includes a planetary gear mechanism 71, a reverse clutch C1, and a forward brake B1.

  The planetary gear mechanism 71 includes a carrier 72, a sun gear 73, and a ring gear 74.

  The carrier 72 is fitted to the input shaft 41 so as to be relatively rotatable. The carrier 72 rotatably supports a plurality of pinion gears 75. The plurality of pinion gears 75 are arranged on the circumference.

  The sun gear 73 is supported by the input shaft 41 so as not to rotate relatively, and is arranged in a space surrounded by a plurality of pinion gears 75. The gear teeth of the sun gear 73 mesh with the gear teeth of each pinion gear 75.

  The ring gear 74 is provided such that its rotation axis coincides with the axis of the primary shaft 51. The primary shaft 51 of the belt transmission mechanism 43 is connected to the ring gear 74. The gear teeth of the ring gear 74 are formed so as to enclose the plurality of pinion gears 75 at a time, and mesh with the gear teeth of each pinion gear 75.

  The reverse clutch C1 is switched between an engaged state (on) in which the carrier 72 and the sun gear 73 are directly connected (integrally rotatable) and a released state (off) in which the direct connection is released.

  The forward brake B1 is provided between the carrier 72 and a transmission case accommodating the torque converter 3 and the continuously variable transmission 4, and is in an engaged state (on) for braking the carrier 72 and released to allow rotation of the carrier 72. State (off).

  When the vehicle 1 moves forward, the reverse clutch C1 is released and the forward brake B1 is engaged. When the power of the engine 2 is input to the input shaft 41, the sun gear 73 rotates integrally with the input shaft 41 with the carrier 72 stationary. Therefore, the rotation of the sun gear 73 is transmitted to the ring gear 74 in the reverse direction and at a reduced speed. Accordingly, the ring gear 74 rotates, and the primary shaft 51 and the primary pulley 53 of the belt transmission mechanism 43 rotate integrally with the ring gear 74. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55, and rotates the secondary pulley 54 and the secondary shaft 52. Then, the output shaft 42 and the output gear 45 rotate integrally with the secondary shaft 52. The output gear 45 meshes with the differential gear 6 (input gear of the differential gear 6). When the output gear 45 rotates, the drive shafts 7 and 8 extending from the differential gear 6 to the left and right rotate, and the vehicle 1 moves forward by rotating drive wheels (not shown).

  On the other hand, when the vehicle 1 moves backward, the reverse clutch C1 is engaged, and the forward brake B1 is released. When the power of the engine 2 is input to the input shaft 41, the carrier 72 and the sun gear 73 rotate integrally with the input shaft 41. Therefore, the rotation of the sun gear 73 is transmitted to the ring gear 74 without the rotation direction being reversed. As a result, the ring gear 74 rotates in a direction opposite to the direction in which the vehicle 1 advances, and the primary shaft 51 and the primary pulley 53 of the belt transmission mechanism 43 rotate integrally with the ring gear 74. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55, and rotates the secondary pulley 54 and the secondary shaft 52. Then, the output shaft 42 and the output gear 45 rotate integrally with the secondary shaft 52. When the output gear 45 rotates, the drive shafts 7, 8 extending left and right from the differential gear 6 rotate in a direction opposite to that in the forward movement, and the drive wheels (not shown) rotate, so that the vehicle 1 moves backward.

<Shift mode>
In the vehicle 1, as the shift mode of the continuously variable transmission 4, the gear ratio is continuously and continuously changed to a gear ratio corresponding to the traveling state of the vehicle 1 irrespective of the operation of the shift lever (shift operation). A stepless automatic transmission mode, a stepped automatic transmission mode in which the transmission ratio is changed in seven steps to a transmission ratio according to the traveling state of the vehicle 1 without using a shift operation, and a transmission operation in which the transmission ratio is changed in seven steps And a manual mode (manual speed change mode) which is changed by.

  The shift lever is provided, for example, on a center console arranged between a driver's seat and a passenger seat. As the positions of the shift lever, for example, a P position, an R position, an N position, and a D position are provided. The P position, the R position, the N position, and the D position correspond to the P range (parking range), the R range (reverse range), the N range (neutral range), and the D range (forward range) of the shift 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 shift range by the shift operation.

  As the position of the shift lever, an S position is provided on the right side of the D position, and a "+" position (upshift position) and a "-" position (downshift position) are provided on the front and rear sides of the S position, respectively. Have been.

  When the shift lever is located at the D position, the continuously variable automatic transmission mode is set. When the shift lever is operated from the D position to the S position, the mode is switched from the continuously variable automatic transmission mode to the stepped automatic transmission mode. When the shift lever is operated from the S position to the “+” position or the “−” position, the mode is switched from the stepped automatic transmission mode to the manual mode. In the manual mode, a single operation of the shift lever from the S position to the “+” position can instruct the change of the gear ratio to a fixed gear ratio one step higher, and the shift lever can be changed from the S position to the “−” position. By changing the speed ratio once, it is possible to instruct to change the speed ratio to a fixed speed ratio one step lower. In the manual mode, the gear ratio can be changed to a fixed gear ratio corresponding to each of the first to seventh gears in an AT (Automatic Transmission) by operating the shift lever.

  In the following description, the fixed speed ratios corresponding to the first to seventh speeds in the AT are simply referred to as “first to seventh speeds”, respectively, and “the first to seventh speeds” are collectively referred to as “speed stages”.

  The vehicle 1 may be provided with a paddle switch in addition to the shift lever. The paddle switch is a momentary operation type switch, and is disposed, for example, on the front side of the steering wheel (the front side in the front-rear direction of the vehicle 1) and on both left and right sides of the steering shaft. One paddle switch is an upshift “+” paddle switch, and the other paddle switch is a downshift “−” paddle switch.

  In the state where the shift lever is located at the S position, a single operation of the upshift "+" paddle switch allows an instruction to change the gear ratio to a fixed gear ratio one step higher. Further, by operating the downshift "-" paddle switch once, it is possible to instruct to change the gear ratio to a fixed gear ratio one step lower.

  When a paddle switch is provided, a signal output in a pulsed manner by the momentary operation of the paddle switch is input to the CVT ECU 12.

<Downshift processing>
FIG. 3 is a flowchart showing the flow of the downshift process. FIG. 4 shows the time change of the accelerator operation (on / off), brake operation (on / off), master cylinder pressure, engine speed, vehicle speed, acceleration, and state of the automatic upshift inhibition flag during downshift. 6 is a graph showing an example of the above.

  When the shift lever is operated to the "-" position or the "-" paddle switch is operated while the vehicle 1 is running in the manual mode, the CVT ECU 12 executes a downshift process for downshifting the gear position. Is done.

  When the downshift process is started, first, various information such as an engine speed, a shift range, a vehicle speed, an acceleration of the vehicle 1, and a current gear position are acquired (step S1). The acceleration of the vehicle 1 can be obtained (calculated) by, for example, time differentiation of the vehicle speed.

  Next, it is determined whether a predetermined precondition is satisfied (step S2). The preconditions include the following conditions (1) to (5).

(1) The accelerator opening is smaller than a predetermined value (the accelerator operation is off).
(2) The brake operation is being performed (the brake operation is on).
(3) The master cylinder pressure is equal to or higher than a predetermined value.
(4) The acceleration of the vehicle 1 is less than a predetermined value (the deceleration of the vehicle 1 is larger than a predetermined value).
(5) The vehicle speed is higher than the downshift permission vehicle speed (before correction).

  If all of the conditions (1) to (5) are satisfied, it is determined that the precondition is satisfied.

  If the precondition is not satisfied (NO in step S2), the downshift process is terminated without downshifting the gear.

  If the precondition is satisfied (YES in step S2), the downshift permission vehicle speed is corrected (step S3). The downshift permission vehicle speed before correction (hereinafter, referred to as “downshift permission vehicle speed before correction”) is predetermined for each shift speed.

  That is, the shift time T required for downshifting from the current shift speed to the lower shift speed by one speed is calculated to correct the downshift permission vehicle speed. The shift time T varies according to the current gear position, engine speed, vehicle speed, oil temperature, state of the lock-up clutch 33, and the like, and is calculated in consideration of these factors. Further, a predetermined additional time α is added to the shift time T, and the added value (T + α) is set as the advance time. After setting the advance time, the corrected vehicle speed is calculated by multiplying the acceleration of the vehicle 1 (a negative value when decelerating) and the advance time (T + α). Then, the corrected downshift permission vehicle speed (hereinafter, referred to as “correction downshift permission vehicle speed”) is calculated by adding the absolute value of the correction vehicle speed to the pre-correction downshift permission vehicle speed corresponding to the current gear position. Thus, the correction of the downshift permission vehicle speed is achieved.

  After the downshift permission vehicle speed is corrected, it is determined whether the vehicle speed is lower than the corrected downshift permission vehicle speed (step S4).

  If the vehicle speed is lower than the corrected downshift permission vehicle speed (YES in step S4), it is determined whether the vehicle speed is lower than the automatic upshift vehicle speed corresponding to the shift speed after the downshift (step S4). Step S5).

  The automatic upshift vehicle speed is a fixed value set for each gear, and is a threshold value for automatically upshifting the gear. With the automatic upshift prohibition flag provided in the memory of the CVT ECU 12 turned off, when the vehicle 1 accelerates in the manual mode and the vehicle speed increases to the automatic upshift vehicle speed, the shift speed is shifted by one speed higher than the current shift speed. Automatically upshifts to the next step. In a state where the automatic upshift prohibition flag is on, even if the vehicle speed increases to the automatic upshift vehicle speed, the gear position is not upshifted from the current gear position. Further, the automatic upshift vehicle speed is set to a value larger than the pre-correction downshift permission vehicle speed corresponding to a speed higher by one speed than the speed corresponding to the automatic upshift vehicle speed. For example, while the downshift permission vehicle speed before correction from the third gear to the second gear is set to 65 km / h, the automatic upshift vehicle speed from the second gear to the third gear is set to 70 km / h. ing.

  If the vehicle speed is lower than the corrected downshift permission vehicle speed and the vehicle speed is lower than the automatic upshift vehicle speed corresponding to the gear after the downshift (YES in step S5), the automatic upshift prohibition flag is not turned on. Then, an instruction for downshifting from the current gear to one lower gear is output (ON) (step S6), and the downshift is started (time T1).

  If the vehicle speed is lower than the corrected downshift permission vehicle speed and the vehicle speed is higher than or equal to the automatic upshift vehicle speed corresponding to the shift speed after the downshift (NO in step S5), the automatic upshift prohibition flag is turned on. (Step S7), an instruction for downshifting from the current gear position to a lower gear position is output (Step S6).

  After the automatic upshift prohibition flag is turned on, as shown in FIG. 4, when the vehicle speed falls below the automatic upshift vehicle speed, the flag is switched from on to off (time T2). As a result, it is possible to prevent the vehicle from being upshifted immediately after the downshift because the vehicle speed is equal to or higher than the automatic upshift vehicle speed, and to maintain the gear position desired by the driver after the downshift. Also when the vehicle speed has risen above the corrected downshift permission vehicle speed (step S4: NO), the automatic upshift prohibition flag is switched from on to off (step S8).

<Effects>
As described above, in the manual mode, when the deceleration of the vehicle 1 is large, the shift time T required for downshifting from the current shift speed to the next lower shift speed is calculated, and the shift time T is set to a predetermined value. The additional time α is added, and the added value (T + α) is set as the advance time. Then, the multiplied value of the acceleration of the vehicle 1 and the advance time is set as the corrected vehicle speed, and the absolute value of the corrected vehicle speed is added to the pre-correction downshift permission vehicle speed. It is corrected to the permitted vehicle speed.

  As described above, in the manual mode, the deceleration of the vehicle 1 (acceleration when the deceleration direction is set to the positive direction) is acquired, and the larger the deceleration, the larger the corrected vehicle speed is set. A correction for raising the vehicle speed by the corrected vehicle speed is performed. This makes it possible to prevent the downshift from being prohibited because the vehicle speed is equal to or higher than the downshift permission vehicle speed when the driver performs a shift operation instructing a downshift during sports driving on a circuit or the like. Downshift at the timing desired by the user.

  Therefore, the deceleration performance and the operability during sports running in the manual mode are improved.

  FIG. 5 is a graph showing the relationship between the vehicle speed and the engine speed.

  The larger the additional time α when setting the corrected vehicle speed, the larger the absolute value of the corrected vehicle speed, and a downshift at a high vehicle speed is permitted. If the gear is downshifted to a lower gear at a higher vehicle speed, the engine speed may increase too much, causing a problem that affects the structure and reliability of the engine 2 and the continuously variable transmission 4. Therefore, the maximum guard speed is set, and when the engine speed rises to the maximum guard speed with the downshift, the speed of the continuously variable transmission 4 is changed so that the engine speed does not exceed the maximum guard speed. Control for changing the ratio is executed. Thus, the engine 2 and the continuously variable transmission 4 can be protected from overspeed while improving the deceleration performance and the operability in the manual mode.

  The additional time α used for setting the corrected vehicle speed may be set to zero. That is, the shift time T may be set as the advance time, and the multiplied value of the acceleration of the vehicle 1 and the shift time T, which is the advance time, may be set as the corrected vehicle speed. Thus, the downshift from the current gear to the lower gear can be completed in accordance with the timing at which the vehicle speed decreases to the pre-correction downshift permission vehicle speed (time T3 in FIG. 4).

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

  For example, in the above-described embodiment, the shift time T required for downshifting from the current shift speed to the next lower shift speed is calculated. However, the shift time T may be fixed to a standard time required for downshifting from the current shift speed to a lower shift speed.

  Further, an added value of the shift time T and a predetermined additional time α (including α = 0) is set as the advance time, and the product of the acceleration of the vehicle 1 and the advance time (T + α) is the correction time. Was set to. The present invention is not limited to this, and a multiplication value of the acceleration of the vehicle 1 and a value irrelevant to the shift time T may be set as the correction time. That is, the correction time may be set so that its absolute value increases as the acceleration of the vehicle 1 increases, and the setting method is not particularly limited.

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

Reference Signs List 1 vehicle 4 continuously variable transmission 12 CVT ECU (control device, mode setting means, downshift permission means, correction means)

Claims (1)

A control device for controlling the continuously variable transmission, which is used in a vehicle equipped with a continuously variable transmission that outputs the driving force by continuously changing the driving force,
A mode for selectively setting an automatic transmission mode in which the gear ratio is changed without using a shift operation and a manual transmission mode in which the gear ratio is changed in response to a shift operation between a plurality of fixed gear ratios set in steps. Setting means;
In the manual shift mode, the vehicle speed of the vehicle is acquired, and when the vehicle speed is equal to or higher than a predetermined automatic upshift vehicle speed, an automatic upshift that changes the gear ratio from the current fixed gear ratio to a fixed gear ratio one step higher. Means,
In the manual shift mode, the vehicle speed of the vehicle is acquired, and when the vehicle speed is equal to or higher than the downshift permission vehicle speed, a change from the current fixed gear ratio to the fixed gear ratio one step lower is prohibited, and the vehicle speed is reduced to the vehicle speed. Downshift permitting means for permitting a change from the current fixed gear ratio to a fixed gear ratio one step lower when the vehicle speed is lower than the downshift permit vehicle speed;
In the manual shift mode, a correction unit that acquires the deceleration of the vehicle and performs a correction to increase the downshift permission vehicle speed in a larger width as the deceleration is larger ,
Upshift prohibiting means for prohibiting the automatic upshift means from changing the gear ratio when the vehicle speed of the vehicle is lower than the downshift permission vehicle speed after correction by the correction means and the vehicle speed is equal to or higher than the automatic upshift vehicle speed. And a control device.

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