JP2014137105A - Shift control device of continuously variable transmission for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shift control device of a continuously variable transmission for a vehicle which can obtain a sufficient acceleration feeling even if the traveling resistance of the vehicle is increased.SOLUTION: In a gear change control device, a gear change ratio γ of a continuously variable transmission 18 is controlled so that an input shaft rotation speed Nin of the continuously variable transmission 18 reaches a preset gear change target value (target input shaft rotation speed Nint), and the gear change target value (target input shaft rotation speed Nint) is corrected according to a change rate of a vehicle speed V during vehicle acceleration. Since traveling resistance amount correction control is performed for correcting the gear change target value (target input shaft rotation speed Nint) according to the traveling resistance (road face gradient θ) of a vehicle, an acceleration feeling of the vehicle by an acceleration operation can be suitably obtained irrespective of the traveling resistance of the vehicle.

Description

  The present invention relates to a shift control device for a continuously variable transmission for a vehicle, and more particularly to a technique for maintaining and improving the feeling of acceleration operation regardless of the traveling load of the vehicle.

  The actual input shaft rotational speed or gear ratio of the continuously variable transmission is set based on the vehicle state represented by the required acceleration amount such as the accelerator opening or the throttle valve opening and the transmission output rotational speed such as the vehicle speed. 2. Description of the Related Art A shift control device for a continuously variable transmission for a vehicle that changes a gear ratio of a continuously variable transmission so as to become a shift target value is well known. For example, the target input shaft rotational speed or the target gear ratio is determined based on the accelerator opening and the vehicle speed from the relationship stored in advance, and the actual input shaft rotational speed or gear ratio of the continuously variable transmission is determined as the target input shaft rotational speed or The required output amount is determined based on the accelerator opening and the vehicle speed based on the speed ratio control that feedback-controls the speed ratio of the continuously variable transmission so as to match the target speed ratio, or the relationship stored in advance. The engine output to be obtained and the target input shaft rotational speed or target speed ratio of the continuously variable transmission are determined, and the throttle valve opening is controlled to obtain the engine output, and at the same time, the target input shaft rotational speed or target This is a gear ratio control that feedback-controls the gear ratio of the continuously variable transmission so that the actual input shaft rotation speed or the gear ratio matches the gear ratio. Such gear ratio control of a continuously variable transmission for a vehicle is described in, for example, Patent Documents 1-3.

  According to the above transmission control device for a continuously variable transmission for a vehicle, on a flat road, a feeling of acceleration in line with the driver's intention to accelerate indicated by the accelerator opening is obtained. Further, in a vehicle equipped with a continuously variable transmission described in Patent Documents 1 and 2, the shift target value is corrected in accordance with the amount of change in vehicle speed, so that even if the accelerator depression amount does not change, the vehicle speed increases. Since the shift target value is corrected to the low gear side, a higher acceleration feeling can be obtained.

JP 2006-051842 A JP 2009-121394 A Japanese Patent No. 4624028

  By the way, according to the conventional transmission control device for a continuously variable transmission for a vehicle, a high acceleration feeling can be obtained even if there is no change in the amount of depression after the accelerator is depressed. Expected by the driver. However, when the running resistance of the vehicle increases due to uphill running, even if the acceleration operation amount is the same, the vehicle speed increase rate is low compared to a flat road, and the change in the shift target value becomes gradual, and the feeling of acceleration decreases. Furthermore, since the speed change target value changes gradually, the rate of increase of the engine speed is slow and the driving force output from the engine is suppressed, so that the vehicle speed rises slowly and the speed change target value changes due to the vehicle speed increase rate. However, there is a problem that the acceleration feeling cannot be further obtained.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to change the speed of a continuously variable transmission for a vehicle that can obtain a sufficient acceleration feeling even if the running resistance of the vehicle increases. It is to provide a control device.

  In order to achieve the above object, the gist of the present invention is that (a) the gear ratio of the continuously variable transmission is set so that the input shaft rotational speed or the gear ratio of the continuously variable transmission becomes a predetermined shift target value. And a shift control device for a continuously variable transmission for a vehicle that corrects the shift target value according to the vehicle speed change rate during vehicle acceleration, and (b) the shift according to the running resistance of the vehicle The object is to perform a running resistance correction control for correcting the target value.

  According to the shift control device for a continuously variable transmission for a vehicle configured as described above, a vehicle speed change correction control that corrects the shift target value of the shift control of the continuously variable transmission according to the vehicle speed change rate during vehicle acceleration. In addition, since the running resistance correction control for correcting the shift target value according to the running resistance of the vehicle is performed, a feeling of acceleration of the vehicle due to the acceleration operation can be suitably obtained regardless of the running resistance of the vehicle.

  Here, preferably, the shift target value is changed so that the continuously variable transmission is on the low gear side as the running resistance of the vehicle increases. In this way, a feeling of acceleration of the vehicle by the acceleration operation can be suitably obtained regardless of an increase in the running resistance of the vehicle.

  Preferably, the shift target value is changed so that the continuously variable transmission is on the high gear side as the running resistance of the vehicle decreases. In this way, excessive acceleration feeling is suppressed when the running resistance of the vehicle is reduced, and a feeling of acceleration of the vehicle by the acceleration operation can be suitably obtained regardless of the reduction of the running resistance of the vehicle.

  Preferably, when the running resistance of the vehicle is less than a preset running resistance increase determination value, the running resistance correction control is prohibited. Since the detection of the running resistance is not necessarily high in accuracy, the running resistance correction control is prevented from being performed unnecessarily.

  Preferably, the shift control device rotates the input shaft of the continuously variable transmission as the vehicle speed increases when the accelerator opening is high acceleration traveling exceeding a preset high acceleration determination value. A stepped (step) shift mode is executed in which the shift target value is changed so that the speed repeatedly increases and decreases rapidly, and the running resistance correction control is executed when in the stepped shift mode. . In this way, the stepped speed change mode in which the shift target value is changed so that the input shaft rotational speed of the continuously variable transmission repeatedly increases and decreases with increasing vehicle speed is executed at high acceleration. Therefore, in the high acceleration traveling, there is an advantage that an acceleration feeling can be obtained regardless of the traveling resistance of the vehicle.

  Preferably, the vehicle has a normal driving mode and a power driving mode selected by a driver's operation, and the power driving mode has a higher input shaft rotation speed of the continuously variable transmission than the normal driving mode. The shift target value is set on the side, and the running resistance correction control is executed when the power mode is selected. Therefore, since the shift target value is set on the side where the input shaft rotational speed of the continuously variable transmission is increased, acceleration feeling is obtained regardless of the running resistance of the vehicle in the power mode having a relatively large driving force. There are advantages to being

  Preferably, the running resistance of the vehicle is detected based on the gradient of the running road surface of the vehicle. The road surface gradient is detected based on the difference between the reference acceleration obtained based on the actual throttle valve opening and the actual acceleration from the relationship between the throttle valve opening and the reference acceleration on a flat road. In this way, the road surface gradient is detected without mounting the G sensor on the vehicle.

It is a figure explaining the schematic structure of the power transmission path | route of the vehicle containing the continuously variable transmission to which this invention is applied. It is a block diagram explaining the principal part of the electronic control apparatus provided in the vehicle of FIG. It is a functional block diagram explaining the principal part of the control function of the electronic control apparatus of FIG. FIG. 4 is a diagram illustrating a relationship for calculating a target input shaft rotational speed based on a vehicle speed and an accelerator opening or a throttle opening in the target input shaft rotational speed calculation unit of FIG. 3. It is a figure explaining the relationship which calculates the running resistance part correction value for correct | amending a target input shaft rotational speed in the running resistance part correction | amendment part of FIG. 3 based on a road surface gradient. It is a flowchart explaining the principal part of the control action of the electronic controller of FIG. It is a time chart explaining the principal part of the control action of the electronic controller of FIG.

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

  FIG. 1 is a diagram schematically illustrating the configuration of a power transmission path from an engine 12 to drive wheels 24 provided in a vehicle 10 to which the present invention is applied. In FIG. 1, the power generated by the engine 12 passes from a torque converter 14 as a fluid transmission device to a forward / reverse switching device 16, a vehicle continuously variable transmission 18, a reduction gear device 20, a differential gear device 22, and the like. , Transmitted to the left and right drive wheels 24L and 24R.

  The torque converter 14 includes a pump impeller 14p connected to the crankshaft 13 of the engine 12, a turbine impeller 14t connected to the forward / reverse switching device 16 via a turbine shaft 30 corresponding to an output side member of the torque converter 14, And a stator impeller 14s that is prevented from rotating in one direction by a one-way clutch, and power is transmitted between the pump impeller 14p and the turbine impeller 14t via a fluid. . That is, in the torque converter 14 of the present embodiment, the pump impeller 14p corresponds to the input rotating member, the turbine impeller 14t corresponds to the output rotating member, and the power of the engine 12 is transmitted to the continuously variable transmission 18 side via the fluid. Is transmitted to. Further, a lockup clutch 26 is provided between the pump impeller 14p and the turbine impeller 14t so as to directly connect between them, that is, between the input / output rotating members of the torque converter 14. Further, the pump impeller 14p controls the transmission of the continuously variable transmission 18, generates the belt clamping pressure of the continuously variable transmission 18, controls the operation of the lockup clutch 26, or lubricates each part. A mechanical oil pump 28 is connected which is generated by rotationally driving an operating hydraulic pressure as an original pressure for supplying the oil by the engine 12.

  The forward / reverse switching device 16 is mainly composed of a forward clutch C1 and a reverse brake B1 as a starting clutch, and a double pinion type planetary gear device 16p. The turbine shaft 30 of the torque converter 14 is integrally connected to the sun gear 16s, and the input shaft 32 of the continuously variable transmission 18 is integrally connected to the carrier 16c, while the carrier 16c and the sun gear 16s are connected to the forward clutch C1. The ring gear 16r is selectively fixed to a housing 34 as a non-rotating member via a reverse brake B1. The forward clutch C1 and the reverse brake B1 correspond to an intermittent device as a predetermined friction engagement device that transmits the power of the engine 12 to the drive wheel 24 side by engagement, and both are frictionally engaged by a hydraulic cylinder. The hydraulic friction engagement device.

  When the forward clutch C1 is engaged and the reverse brake B1 is released, the forward / reverse switching device 16 is brought into an integral rotation state, whereby the turbine shaft 30 is directly connected to the input shaft 32, and the forward drive power is increased. The transmission path is established (achieved), and the driving force in the forward direction is transmitted to the continuously variable transmission 18 side. When the reverse brake B1 is engaged and the forward clutch C1 is released, the forward / reverse switching device 16 establishes (achieves) the reverse power transmission path, and the input shaft 32 is connected to the turbine shaft 30. On the other hand, it is rotated in the opposite direction, and the driving force in the reverse direction is transmitted to the continuously variable transmission 18 side. When both the forward clutch C1 and the reverse brake B1 are released, the forward / reverse switching device 16 enters a neutral state (power transmission cut-off state) in which power transmission is cut off.

  As the engine 12, for example, a gasoline engine such as an internal combustion engine that generates power by combustion of fuel, a diesel engine, or the like is preferably used, but another prime mover such as an electric motor may be used in combination with the engine. The intake pipe 36 of the engine 12 is provided with a throttle valve 40 that is electrically controlled using a throttle actuator 38 so as to obtain an intake air amount Q of the engine 12 corresponding to the accelerator opening Acc.

  The continuously variable transmission 18 is an input side member provided on the input shaft 32 and an effective diameter that is an output side member provided on the drive side pulley (primary pulley, primary sheave) 42 and the output shaft 44 having a variable effective diameter. Is provided with a pair of variable pulleys 42 and 46 of a variable driven pulley (secondary pulley, secondary sheave) 46, and a transmission belt 48 wound between the pair of variable pulleys 42 and 46. This is a belt type continuously variable transmission in which power is transmitted through frictional forces between the variable pulleys 42 and 46 and the transmission belt 48.

  The driving pulley 42 includes a fixed rotating body 42a fixed to the input shaft 32, a movable rotating body 42b provided so as not to be rotatable relative to the input shaft 32 and movable in the axial direction, and a space between them. And a drive side hydraulic cylinder (primary pulley side hydraulic cylinder) 42c as a hydraulic actuator for applying a thrust for changing the V groove width. The driven pulley 46 includes a fixed rotating body 46a fixed to the output shaft 44, a movable rotating body 46b provided so as not to be rotatable relative to the output shaft 44, and movable in the axial direction. And a driven hydraulic cylinder (secondary pulley hydraulic cylinder) 46c as a hydraulic actuator that applies thrust for changing the V groove width between the two. In the continuously variable transmission 18 configured in this way, for example, the supply / discharge flow rate of hydraulic oil to the drive side hydraulic cylinder 42c is controlled by a shift control valve 70 provided in a hydraulic control circuit (not shown), whereby a pair of The V-groove width of the variable pulleys 42 and 46 is changed to change the engagement diameter (effective diameter) of the transmission belt 48, and the transmission gear ratio (gear ratio) γ (= input shaft rotational speed Nin / output shaft rotational speed Nout) is continuous. Can be changed. The secondary pressure Pout (corresponding to the belt clamping pressure Pd), which is the hydraulic pressure of the driven hydraulic cylinder 46c, is regulated by the clamping pressure control valve 72 provided in the hydraulic control circuit 100, so that the transmission belt 48 is The frictional force (belt clamping pressure) between the pair of variable pulleys 42 and 46 and the transmission belt 48 is controlled in accordance with the secondary pressure Pout so that no slippage occurs. As a result of such control, a primary pressure (shift control pressure) Pin, which is the hydraulic pressure of the drive side hydraulic cylinder 42c, is generated.

  FIG. 2 is a block diagram illustrating a main part of a control system provided in the vehicle 10 in order to control the engine 12, the continuously variable transmission 18, and the like. In FIG. 2, the vehicle 10 is provided with an electronic control device 50 including a shift control device related to, for example, shift control of the continuously variable transmission 18. The electronic control unit 50 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, for example, and the CPU stores a program stored in the ROM in advance using a temporary storage function of the RAM. Various control of the vehicle 10 is executed by performing signal processing according to the above. For example, the electronic control unit 50 performs output control of the engine 12, shift control of the continuously variable transmission 18, belt clamping pressure control, torque capacity control of the lockup clutch 26, and the like. The engine control, the continuously variable transmission 18 and the lockup clutch 26 are controlled separately.

  The electronic control unit 50 includes, for example, an engine rotation speed Ne (rpm) which is the rotation angle (position) ACR of the crankshaft 13 detected by the engine rotation speed sensor 52 and the rotation speed of the crankshaft 13 (that is, the rotation speed of the engine 12). ), A signal representing the turbine rotational speed Nt (rpm) which is the rotational speed of the turbine shaft 30 detected by the turbine rotational speed sensor 54, and the input of the continuously variable transmission 18 detected by the input shaft rotational speed sensor 56. The output shaft 44 of the continuously variable transmission 18 corresponding to the signal representing the input shaft rotational speed Nin (rpm) that is the rotational speed of the shaft 32 and the vehicle speed V detected by the output shaft rotational speed sensor 58 that also functions as a vehicle speed sensor. A signal representing the output shaft rotation speed Nout (rpm), which is the rotation speed, and the electronic speed detected by the throttle sensor 60. A signal indicating the throttle valve opening degree θth (%), which is the opening degree of the throttle valve 40, a signal indicating the cooling water temperature Tw (° C.) of the engine 12 detected by the engine water temperature sensor 62, and an accelerator operation amount sensor 64 A signal representing the accelerator opening degree Acc (%), which is the operation amount of the accelerator pedal 65 as the acceleration request amount (driver request amount) for the vehicle 10 by the driver, the P of the shift lever 68 detected by the shift lever operation position sensor 66 , P, N, D, M, a signal representing the lever position (operation position) Psh, a signal representing the power mode selection output from the power mode selection switch 69 operated by the driver, and the like are supplied. The

  In addition, the electronic control unit 50 requires and sufficiently provides, for example, an accelerator opening command signal output to set the throttle valve 40 to an opening corresponding to the accelerator opening Acc, and the belt clamping pressure of the continuously variable transmission 18. A belt clamping pressure command signal to the clamping pressure control valve 70 for obtaining a small value, a shift control command signal to the transmission control valve 72 for changing the transmission gear ratio γ of the continuously variable transmission 18 and the like are output. As described above, the electronic control device 50 also functions as a shift control device.

  FIG. 3 is a functional block diagram for explaining a main part of the shift control function by the electronic control unit 50. In FIG. 3, the power mode determination unit 80 determines that the power mode is selected from the normal mode based on the operation of the power mode selection switch 69. The in-acceleration determination unit 82 determines that the vehicle is increasing, that is, in an acceleration state, based on the change amount of the vehicle speed V detected by the output shaft rotation speed sensor 58 being a positive value. When the shift lever 68 is operated to the D position, the stepped transmission mode determination unit 84 does not exceed the high acceleration determination value A that is set in advance such that the accelerator opening Acc or the throttle valve opening θth is about 30%. In the case of normal acceleration traveling, the target input shaft rotational speed Nint is continuously set so as to gradually change as the vehicle speed increases as shown by the broken line in FIG. The normal speed change mode in which the engine speed is gradually changed is determined. If the accelerator opening degree Acc or the throttle valve opening degree θth is high acceleration traveling exceeding the high acceleration determination value, as shown by the solid line in FIG. In addition, the target input shaft rotation speed Nint is set so as to repeat the gradual increase and decrease of the target input shaft rotation speed Nint during acceleration, and the gear ratio γ is automatically stepped (stepwise) like a stepped transmission. Change to Stepped shift mode to - de (step shift mode - de) It is, and determines that a gradual increase interval of the target input shaft rotational speed Nint.

  The shift target value calculation unit 86 sets a shift target value to be subjected to shift control based on the vehicle state indicated by the actual vehicle speed V and the accelerator opening Acc. In the normal speed change mode, for example, as shown in FIG. 4, two-dimensional coordinates of the axis indicating the target input shaft rotational speed Nint and the axis indicating the vehicle speed V are stored in advance as indicated by a broken line with the accelerator opening Acc as a parameter. From the relationship (map), the target input shaft rotational speed Nint, which is the shift target value, is determined as the shift target value based on the actual vehicle speed V and the accelerator opening Acc. Further, in the stepped speed change mode, the speed change target value calculation unit 86, together with the vehicle speed V, uses at least one of the throttle opening degree θth, the accelerator opening degree Acc, and the intake air amount as parameters, as shown by the solid line in FIG. The rising upper limit rotational speed NH and the lower limit rotational speed NL are determined, and the target input shaft rotational speed Nint is determined so as to repeat the gradual increase and rapid decrease between the upper limit rotational speed NH and the lower limit rotational speed NL. In the gradual increase section of the target input shaft rotational speed Nint, the speed ratio γ is kept constant and the acceleration state is established, but in the sudden decrease section, the speed ratio γ is increased.

When the power mode is selected, the vehicle speed change correction unit 88 is switched to the stepped speed change mode, and the vehicle is increasing in speed, the engine speed is increased as the vehicle speed is increased, so that a suitable acceleration is achieved. In order to obtain a feeling, for example, a vehicle speed change correction value Ninv is calculated based on the actual vehicle speed V and the vehicle speed change amount (V−V ⁻¹ ) sequentially detected from the relationship shown in the equation (1), and the shift target value The target input shaft rotational speed Nint calculated by the calculation unit 86 is corrected using the vehicle speed change correction value Ninv, and the corrected target input shaft rotational speed Nint ′ (= Nint + Ninv) is output. The vehicle speed change correction value Ninv in this case can be converted to a coefficient value smaller than 1 by normalization or the like, but in this case, the corrected target input shaft rotational speed is Nint × Ninv. In other words, the vehicle speed change correction unit 88 is a target input shaft rotation speed that is a shift target value so that the continuously variable transmission 18 becomes the low gear side as the vehicle speed V and the vehicle speed change amount (V-V ^-1 ) increase. Nint is changed and the corrected target input shaft rotational speed Nint ′ is output.
Ninv = ∫ [β (v, acc) × (V−V ⁻¹ ) dt (1)

  When the power mode is selected, the travel resistance component correction unit 90 is switched to the stepped speed change mode, and the vehicle is speeding up, first, the climbing slope θ (°) of the travel road surface is used as the travel resistance. To detect. For example, the traveling resistance correction unit 90 is based on the difference between the reference acceleration corresponding to the actual accelerator opening Acc and the actual acceleration from the relationship between the accelerator opening Acc and the reference acceleration obtained on a flat road. The gradient θ (°) of the road surface on which the vehicle travels is calculated. Next, the travel resistance correction unit 90 calculates a travel resistance correction value Nina based on the actual gradient θ (the climbing slope is positive and the descending slope is negative) from, for example, the previously stored relationship shown in FIG. , The target input shaft rotational speed Nint ″ (= Nint ′ × Nina) after the correction of the running resistance is output. That is, the running resistance correction unit 90 causes the continuously variable transmission 18 to move to the high gear as the running resistance of the vehicle decreases. In other words, in other words, the target input shaft rotational speed Nint is changed so that the continuously variable transmission 18 becomes the low gear side as the traveling resistance of the vehicle increases, and the target input shaft rotational speed Nint after correcting the traveling resistance is adjusted. "Is output.

  The hard limit determination unit 92 is a value in which the target input shaft rotational speed Nint "after correction for the running resistance exceeds a change range permitted by the mechanism of the continuously variable transmission 18 at the vehicle speed V at that time, That is, it is determined whether or not the value exceeds the hard limit, and the gradient determination unit 94 has a gradient θ of the road surface on which the vehicle travels exceeds a predetermined climb gradient determination value θA, for example, about + 3 °. In other words, it is determined whether or not the road surface is an uphill gradient or a downhill gradient based on falling below a predetermined downward gradient determination value θB of about −3 °.

  The gear ratio control unit 96 determines that the power mode is not selected by the power mode determination unit 80 during the D position traveling, and determines that the vehicle is not being accelerated by the acceleration determination unit 82, and the stepped transmission mode The determination unit 84 determines that the stepped speed change mode is not selected, and the hardware limit determination unit 92 determines that the target input shaft rotational speed Nint ″ after the travel resistance correction is a value exceeding the hard limit, Alternatively, when it is determined by the gradient determination unit 94 that the road surface is not a gradient, the target input shaft rotational speed Nint ”that has been subjected to the vehicle speed change correction and the speed travel resistance correction for the target input shaft rotational speed Nint is not used. The shift control is performed using the target input shaft rotational speed Nint before correction. That is, the transmission control valve 72 is operated so that the actual input shaft rotational speed Nin matches the target input shaft rotational speed Nint, and the speed ratio is feedback controlled.

  However, during driving in the D position, it is determined that the power mode is selected by the power mode determination unit 80, the vehicle speed increase determination unit 82 determines that the vehicle is being accelerated, and the stepped transmission mode determination unit 84 determines It is determined that the stepped speed change mode is selected and the vehicle is in the acceleration state, and it is determined by the hardware limit determination unit 92 that the target input shaft rotational speed Nint ″ after the correction of the running resistance does not exceed the hardware limit, and When the gradient determination unit 94 determines that the road surface is a gradient, the gear ratio control unit 96 performs target input shaft rotation in which vehicle speed change correction and speed running resistance correction are performed with respect to the target input shaft rotation speed Nint. Shift control is performed using the speed Nint ″. In other words, the transmission control valve 72 is operated so that the actual input shaft rotational speed Nin coincides with the target input shaft rotational speed Nint ″ after the vehicle speed change correction and travel resistance correction, and the speed ratio is feedback controlled.

  FIG. 6 is a flowchart for explaining a main part of the control operation of the electronic control unit 50, that is, correction control of the shift target value. FIG. 7 is a time chart for explaining the operation when the control shown in the flowchart of FIG. 6 is executed.

  In FIG. 6, in step S <b> 1 (hereinafter, step is omitted) corresponding to the power mode determination unit 80, it is determined whether or not the acceleration-oriented power mode is selected by the driver. If the determination in S1 is negative, this routine is terminated. If the determination is positive, the routine is switched to the stepped transmission mode in S2 and S3 corresponding to the stepped transmission mode determination unit 84. It is determined whether or not the vehicle is in an accelerating state in a gradually increasing section of the target input shaft rotation speed Nint. If the determination in S2 or S3 is negative, this routine is terminated. If the determination in S2 and S3 is affirmative, in S4 corresponding to the hardware limit determination unit 92, the vehicle speed change correction and the speed running are performed. It is determined whether or not the target input shaft rotational speed Nint ″ subjected to resistance correction exceeds the change range allowed by the mechanism of the continuously variable transmission 18 at the vehicle speed V at that time. If the determination is negative, this routine is terminated. If the determination in S4 is affirmative, whether or not the vehicle is being accelerated, that is, whether the vehicle is in an accelerated state or not, in S5 corresponding to the acceleration determining unit 82. If the determination in S5 is negative, this routine is terminated, but if the determination is affirmative, in S6 corresponding to the gradient determination unit 94, the road surface on which the vehicle travels is inclined. If the determination in S6 is negative, this routine is terminated, but if the determination is affirmative, the vehicle speed change correction unit 88 and the running resistance correction unit 90 are informed. Corresponding S7 is executed.

  In S7, during driving in the D position, the power mode is selected, the vehicle speed is being increased, the stepped speed change mode is selected and the vehicle is in the acceleration state, and the target input shaft rotational speed Nint after correction for the running resistance is performed. Since “” does not exceed the hard limit and the road surface is a gradient road surface, the vehicle speed change correction value Ninv is calculated based on the actual vehicle speed V sequentially detected from the relationship shown in the equation (1). In addition, a running resistance correction value Nina is calculated based on the actual climb gradient θ (positive value) from the relationship stored in advance shown in FIG. 5, and the vehicle speed change correction value Ninv and the running resistance correction value Nina are calculated. Is used to correct the target input shaft rotational speed Nint, thereby calculating the target input shaft rotational speed Nint ″ after the travel resistance correction.

  In FIG. 7, the t0 to t1 sections are in the D position traveling, the power mode is selected, the vehicle is being accelerated, the stepped speed change mode is selected, and the vehicle is in the accelerated state, and after the running resistance is corrected The target input shaft rotational speed Nint ”does not exceed the hard limit, and shows a state before correction using the running resistance correction value Nina. In this section, the target input shaft rotational speed Nint ′ is a solid line However, the time point t1 indicates a point in time when it is determined that the road surface is a gradient road and correction using the running resistance correction value Nina is started, and the t1 to t2 section is corrected for the running resistance. The subsequent target input shaft rotational speed Nint ″ is indicated by a broken line, and the target input shaft rotational speed before correction is indicated by a solid line Nint ′. The difference between the solid line and the broken line indicates the correction amount for the running resistance.

  As described above, according to the present embodiment, the transmission ratio of the continuously variable transmission 18 is set so that the input shaft rotation speed Nin of the continuously variable transmission 18 becomes a predetermined shift target value (target input shaft rotation speed Nint). In a shift control device of a type that controls γ and corrects the shift target value (target input shaft rotational speed Nint) according to the rate of change of the vehicle speed V during vehicle acceleration, the vehicle running resistance (road slope θ) Accordingly, since the running resistance correction control for correcting the shift target value (target input shaft rotational speed Nint) is performed, the acceleration feeling of the vehicle by the acceleration operation can be suitably obtained regardless of the running resistance of the vehicle.

  Further, according to the present embodiment, the speed change target value (target input shaft rotational speed Nint) is changed so that the gear ratio of the continuously variable transmission 18 becomes the low gear side as the running resistance of the vehicle increases. A feeling of acceleration of the vehicle due to the operation can be suitably obtained regardless of an increase in the running resistance of the vehicle.

  In addition, according to the present embodiment, the shift target value is changed so that the continuously variable transmission 18 becomes the high gear side as the running resistance (road surface gradient θ) of the vehicle decreases. Generation of excessive acceleration feeling is suppressed, and the acceleration feeling of the vehicle by the acceleration operation can be suitably obtained regardless of the decrease in the running resistance of the vehicle.

  Further, according to the present embodiment, when the running resistance (road surface gradient θ) of the vehicle is less than a predetermined running resistance increase determination value (road surface gradient determination value θA), the running resistance correction control is prohibited. . Since the detection of the running resistance is not necessarily highly accurate, this prevents the running resistance correction control from being performed unnecessarily.

  Further, according to the present embodiment, the electronic control unit 50 functioning as a shift control unit increases the vehicle speed V when the accelerator opening degree Acc is high acceleration traveling exceeding a preset high acceleration judgment value A. Accordingly, a stepped (step) shift mode is executed in which the shift target value (target input shaft rotation speed Nint) is changed so that the input shaft rotation speed Nin of the continuously variable transmission 18 repeats gradually increasing and decreasing. The running resistance correction control is executed when in the stepped speed change mode. For this reason, the stepped transmission mode in which the shift target value (target input shaft rotation speed Nint) is changed so that the input shaft rotation speed Nin of the continuously variable transmission 18 gradually increases and decreases as the vehicle speed increases is high acceleration. Since it is executed by traveling, there is an advantage that an acceleration feeling can be obtained regardless of the traveling resistance of the vehicle in the high acceleration traveling.

  Further, according to the present embodiment, there are a normal travel mode and a power travel mode selected by the driver's operation, and the power travel mode is the input shaft rotation speed of the continuously variable transmission 18 as compared with the normal travel mode. The shift target value (target input shaft rotational speed Nint) is set on the side where Nin becomes higher, and the running resistance correction control is executed when the power mode is selected. For this reason, since the shift target value is set to the side where the input shaft rotational speed Nin of the continuously variable transmission 18 is increased, an acceleration feeling is obtained regardless of the running resistance of the vehicle in the power mode having a relatively large driving force. There are advantages to being

  Further, according to this embodiment, the road surface gradient θ corresponding to the running resistance of the vehicle is obtained based on the actual throttle valve opening θth from the relationship between the throttle valve opening θth and the reference acceleration on a flat road. The road surface gradient is detected without mounting the G sensor on the vehicle.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

For example, in the transmission ratio control unit 96 described above, the target input shaft rotational speed Nint obtained from the actual vehicle speed V and the accelerator opening degree Acc from the previously stored relationship shown in FIG. 4 is used as the transmission target value for the transmission feedback control. It was used. However, the relationship between the speed ratio γ of the continuously variable transmission 18 and the input shaft rotational speed Nin is expressed by the following equation (2).
γ = Nout / Nin (2)
Since the change directions are opposite but in a one-to-one relationship with each other, the target gear ratio γt obtained from the equation (2) based on the target input shaft rotational speed Nint is the shift target value. May be used. In this case, the transmission ratio control unit 96 controls the transmission control valve 72 so that the actual transmission ratio γ matches the target transmission ratio γt. In addition, the vehicle speed change correction unit 88 changes the speed change gear ratio γt so that the continuously variable transmission 18 becomes the low gear side as the vehicle speed V and the vehicle speed change amount (V−V ⁻¹ ) increase. The target gear ratio γ ′ is output. Further, in the travel resistance correction unit 90, the continuously variable transmission 18 is set to the high gear side as the travel resistance of the vehicle decreases, in other words, the continuously variable transmission 18 is set to the low gear side as the travel resistance of the vehicle increases. Thus, the target speed ratio γ is changed so that the target speed ratio γ ″ after traveling resistance correction is output.

  Further, the shift control system of the above-described embodiment is a system in which the target input shaft rotational speed Nint, which is a shift target value, is obtained based on the actual vehicle speed V and the accelerator opening Acc from the relationship stored in advance shown in FIG. However, for example, the required driving force is determined based on the vehicle speed V and the accelerator opening degree Acc, and the target input shaft rotational speed and the target throttle opening degree of the continuously variable transmission 18 for obtaining the required driving force are obtained. Alternatively, a torque demand method may be employed in which the speed ratio control is executed so as to obtain the target input shaft rotation speed and the throttle actuator 38 is controlled so as to obtain the target throttle opening.

  In the running resistance correction unit 90 of the above-described embodiment, the running resistance correction of the shift target value is executed in the power mode and the stepped mode, but it is not necessarily in the power mode or the stepped mode. It does n’t have to be.

  Further, the continuously variable transmission 18 of the above-described embodiment is a so-called belt in which the transmission belt 48 is wound around a pair of variable pulleys 42 and 48 whose effective diameter is variable, and the speed ratio γ is continuously changed steplessly. In this type of continuously variable transmission, a pair of cones that rotate around a common axis and a plurality of rollers that can rotate around the axis are sandwiched between the pair of cones. Other types of continuously variable transmissions such as a so-called traction type continuously variable transmission in which the gear ratio is variable by changing the intersection angle between the rotation center of the roller and the shaft center may be used.

  Further, as the engine 12 described above, for example, a gasoline engine such as an internal combustion engine that generates power by combustion of fuel or a diesel engine or the like is preferably used, but another prime mover such as an electric motor is used in combination with the engine or independently. You can also

  In the above-described embodiment, the target input shaft rotational speed Nint is used as the shift target value. However, the present invention is applicable to a rotating element that rotates with the input shaft 32, such as the turbine shaft 30 and the crankshaft 13. Can be applied. In such a case, the shift target value is, for example, the target turbine rotational speed NT * or the target engine rotational speed NE *.

  Further, the shift control valve 72 of the above-described embodiment controls the gear ratio of the continuously variable transmission 18 by controlling the flow rate of the hydraulic oil to the primary hydraulic cylinder 42c, but is not limited thereto. For example, the primary pressure Pin to the primary hydraulic cylinder 42c may be directly controlled.

  In the above-described embodiment, the torque converter 14 provided with the lock-up clutch 26 is used as the fluid transmission device. However, the lock-up clutch 26 is not necessarily provided, and the torque converter 14 includes Instead, another fluid type power transmission device such as a fluid coupling (fluid coupling) having no torque amplification action may be used, or a vehicle drive system including an electric motor as a drive source may be used.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

18: Vehicle continuously variable transmission 32: Input shaft 50: Electronic control device (transmission control device)
90: traveling resistance correction unit 80: power mode determination unit 82: in-acceleration determination unit 84: stepped transmission mode determination unit 92: hardware limit determination unit 94: gradient determination unit 96: transmission ratio control unit

Claims (7)

The transmission ratio of the continuously variable transmission is controlled so that the input shaft rotation speed or the transmission ratio of the continuously variable transmission becomes a predetermined shift target value, and the shift target value is set according to the vehicle speed change rate during vehicle acceleration. A shift control device for a continuously variable transmission for a vehicle of a type to be corrected
A shift control apparatus for a continuously variable transmission for a vehicle, characterized in that a running resistance correction control is performed to correct the shift target value in accordance with a running resistance of the vehicle.   The shift control device for a continuously variable transmission for a vehicle according to claim 1, wherein the shift target value is changed so that the continuously variable transmission is on a low gear side as the running resistance of the vehicle increases.   The shift control device for a continuously variable transmission for a vehicle according to claim 1 or 2, wherein the shift target value is changed so that the continuously variable transmission becomes on a high gear side as the running resistance of the vehicle decreases.   The continuously variable transmission for a vehicle according to any one of claims 1 to 3, wherein the running resistance correction control is prohibited when the running resistance of the vehicle is less than a preset running resistance increase determination value. Shift control device. The shift target is set so that the input shaft rotational speed of the continuously variable transmission repeatedly increases and decreases gradually as the vehicle speed increases when the accelerator opening exceeds a preset high acceleration judgment value. Execute the stepped speed change mode to change the value,
The shift control device for a continuously variable transmission for a vehicle according to any one of claims 1 to 4, wherein the running resistance correction control is executed in the stepped shift mode. A normal driving mode and a power driving mode selected by an operator's operation, and in the power driving mode, the shift target is set on the side where the input shaft rotational speed of the continuously variable transmission is higher than in the normal driving mode. Value is set,
The shift control apparatus for a continuously variable transmission for a vehicle according to any one of claims 1 to 5, wherein the running resistance correction control is executed when the power mode is selected.   The shift control device for a continuously variable transmission for a vehicle according to any one of claims 1 to 6, wherein the running resistance of the vehicle is detected based on a gradient of a running road surface of the vehicle.

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