JP2017101708A - Device for controlling continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for controlling a continuously variable transmission that can inhibit generation of a rubber band feeling without impairing advantageous points of continuously variable gear.SOLUTION: The device for controlling a continuously variable transmission sets a hysteresis target gear ratio Gh where the target gear ratio G is imparted with hysteresis based on an accelerator opening degree A, a vehicle speed V and a gear change line map, instead of a target gear ratio G calculated from a target rotation number depending on the accelerator opening degree A and the vehicle speed V, and changes a gear ratio of the continuously variable transmission so as to match with the hysteresis gear ratio Gh.SELECTED DRAWING: Figure 5

Description

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

  A CVT (Continuously Variable Transmission) is widely known as a transmission mounted on a vehicle.

  In a vehicle equipped with a CVT, the relationship between the accelerator opening (the amount of depression of the accelerator pedal), the vehicle speed, and the target rotational speed is defined in a memory of an ECU (Electronic Control Unit) for controlling the transmission ratio. A shift diagram is stored. Based on this shift diagram, a target rotational speed corresponding to the accelerator opening and the vehicle speed is set, and the gear ratio is controlled so that the input rotational speed input to the CVT matches the target rotational speed. As a result, the gear ratio can be continuously changed according to changes in the accelerator opening and the vehicle speed so that the engine speed is included in the high-efficiency rotation range, and the fuel efficiency utilizing the continuously variable transmission can be improved. Good driving can be realized.

JP 2010-112397 A

  However, in a vehicle equipped with a CVT, there is no linear feeling between the accelerator opening and the driving force or between the engine speed and the vehicle speed because the gear ratio changes as the accelerator pedal is depressed or the vehicle speed increases. There is a problem that so-called rubber band feeling occurs.

  The objective of this invention is providing the control apparatus of a continuously variable transmission which can suppress generation | occurrence | production of a rubber band feeling, without impairing the advantage by continuously variable transmission.

  In order to achieve the above object, a continuously variable transmission control device according to the present invention is a continuously variable transmission control device mounted on a vehicle, the accelerator opening obtaining means for obtaining an accelerator opening; Vehicle speed acquisition means for acquiring the vehicle speed of the vehicle, shift diagram storage means for storing a shift diagram that defines the relationship between the accelerator opening and the vehicle speed, and the target value of the input rotational speed input to the continuously variable transmission; Based on the accelerator opening obtained by the accelerator opening obtaining means and the vehicle speed obtained by the vehicle speed obtaining means, hysteresis is given to the target gear ratio determined from the accelerator opening, the vehicle speed, and the shift diagram. Hysteresis target speed ratio setting means for setting the target speed ratio, and speed ratio changing means for changing the speed ratio of the continuously variable transmission to match the hysteresis target speed ratio.

  The shift diagram shows the relationship between the accelerator opening and the vehicle speed and the target input rotational speed of the continuously variable transmission, and has been widely used for controlling the continuously variable transmission. In conventional control, the target input rotational speed corresponding to the current accelerator opening and vehicle speed is set according to the shift diagram, and the gear ratio is set so that the input rotational speed input to the continuously variable transmission matches the target input rotational speed. Is changed. In other words, in the conventional control, the target rotational speed is set from the current accelerator opening, vehicle speed, and shift diagram, and the speed ratio is changed to match the target speed ratio according to the target speed.

  On the other hand, according to the configuration according to the present invention, not the target speed ratio according to the current accelerator opening, the vehicle speed, and the target speed determined from the speed diagram, but the hysteresis in which the target speed ratio is given hysteresis. A target gear ratio is set, and the gear ratio is changed to match the hysteresis gear ratio.

  Thereby, when the increase amount of the accelerator opening is small and the target speed ratio changes within the dead zone of the hysteresis, the hysteresis target speed ratio is kept constant, and the speed ratio of the continuously variable transmission is kept constant. The output rotational speed (vehicle speed) increases with high responsiveness to the increase in the input rotational speed due to the increase in the accelerator opening. As a result, the occurrence of rubber band feeling (rubber band feel) can be suppressed, and a running feeling with a direct feeling (linear feeling) with respect to the accelerator operation can be obtained.

  In addition, when the increase amount of the accelerator opening is large and the target gear ratio changes beyond the dead zone of the hysteresis, the hysteresis target gear ratio continuously changes steplessly according to the increase amount of the accelerator opening. In addition, while being able to obtain an appropriate driving force for accelerating the vehicle, it is possible to achieve traveling with good fuel efficiency utilizing continuously variable transmission.

  Therefore, it is possible to suppress the occurrence of rubber band feeling without impairing the advantages of continuously variable transmission.

  The hysteresis target gear ratio setting means includes a first hysteresis applying means for applying hysteresis to the accelerator opening acquired by the accelerator opening acquiring means, and a second hysteresis applying means for applying hysteresis to the vehicle speed acquired by the vehicle speed acquiring means. And a hysteresis target rotation speed setting means for setting a target rotation speed according to a shift diagram according to the accelerator opening to which the hysteresis is applied by the first hysteresis applying means and the vehicle speed to which the hysteresis is applied by the second hysteresis applying means, The vehicle may be configured to include a calculating unit that calculates a hysteresis target speed ratio from the vehicle speed to which the hysteresis is provided by the second hysteresis applying unit and the target rotational speed set by the hysteresis target rotational speed setting unit.

  The hysteresis target speed ratio setting means includes target speed setting means for setting a target rotational speed according to the accelerator opening obtained by the accelerator opening obtaining means and the vehicle speed obtained by the vehicle speed obtaining means according to the shift diagram. Calculating the target speed ratio from the vehicle speed acquired by the vehicle speed acquisition means and the target speed set by the target speed setting means, and applying hysteresis to the target speed ratio calculated by the calculating means, It may also be configured to include a hysteresis applying means for setting the target gear ratio.

  According to the present invention, it is possible to suppress the occurrence of rubber band feeling without impairing the advantages of continuously variable transmission.

It is a figure which shows the structure of the principal part of the vehicle by which the control apparatus which concerns on one Embodiment of this invention is mounted. It is a skeleton figure which shows the structure of the drive system of a vehicle. It is a block diagram which shows the structure of CVTECU. It is a block diagram which shows the structure of a target value setting part. It is a figure for demonstrating the setting method of the target rotation speed by a target value setting part, (a) Shift diagram, (b) An example of time change of accelerator opening A and hysteresis accelerator opening Ah, (c) Vehicle speed An example of the time change of V and hysteresis vehicle speed Vh, (d) An example of the time change of hysteresis target gear ratio Gh is shown. It is a figure for demonstrating the setting method of target rotational speed N 'by the target value setting part 101, (a) Shift diagram, (b) Other examples of the time change of accelerator opening A and hysteresis accelerator opening Ah (C) Another example of time change of vehicle speed V and hysteresis vehicle speed Vh, (d) Another example of time change of hysteresis target gear ratio Gh is shown. It is a block diagram which shows the other structure of a target value setting part.

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

<Vehicle configuration>
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 that uses the engine 2 as a drive source. The output of the engine 2 is transmitted to the left and right drive 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) that injects fuel into the intake air, and an ignition plug that generates electric discharge in the combustion chamber. It has been. The engine 2 is also provided with a starter for starting the engine 2.

  The vehicle 1 includes a plurality of ECUs (Electronic Control Units) having a configuration including a CPU, a ROM, a RAM, and the like. The plurality of ECUs include an engine ECU 11 and a CVTECU 12. Each ECU is connected so that bidirectional communication by a CAN (Controller Area Network) communication protocol is possible.

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

  The accelerator sensor 21 outputs a detection signal corresponding to the operation amount of the accelerator pedal operated by the driver. Based on the detection 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 the accelerator pedal is depressed to the maximum. The accelerator opening, which is a percentage with the time taken as 100%, is calculated.

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

  The engine ECU 11 is provided in the engine 2 for starting, stopping and adjusting the output of the engine 2 based on information obtained from detection signals of various sensors and / or various information input from other ECUs. Controls electronic throttle valves, injectors, and spark plugs.

  An input rotation speed sensor 23, an output rotation speed sensor 24, and the like are connected to the CVTECU 12.

  The input rotation speed sensor 23 outputs, for example, a pulse signal synchronized with the rotation of the input shaft 41 (see FIG. 2) of the continuously variable transmission 4 as a detection signal. The CVTECU 12 converts the frequency of the pulse signal input from the input rotation speed sensor 23 into an actual input rotation speed that is the actual rotation speed of the input shaft 41.

  The output rotation speed sensor 24 outputs, for example, a pulse signal synchronized with the rotation of the output shaft 42 (see FIG. 2) of the continuously variable transmission 4 as a detection signal. The CVTECU 12 converts the frequency of the pulse signal input from the output rotation speed sensor 24 into an actual output rotation speed that is the actual rotation speed of the output shaft 42.

  The CVTECU 12 controls each part of the continuously variable transmission 4 for the shift control of the continuously variable transmission 4 based on information obtained from detection signals of various sensors and / or various information input from other ECUs. Various valves included in a hydraulic circuit 25 for supplying hydraulic pressure are controlled.

<Configuration of drive system (CVT)>
FIG. 2 is a skeleton diagram showing the configuration of the drive system of the vehicle 1.

  The torque converter 3 includes a pump impeller 31, a turbine runner 32, and a lockup clutch 33. An output shaft (E / G output shaft) of the engine 2 is connected to the pump impeller 31, and the pump impeller 31 is provided so as to be integrally rotatable around the same rotation axis as the E / G output shaft. ing. The turbine runner 32 is provided to be rotatable about the same rotation axis as the pump impeller 31. The lockup clutch 33 is provided to directly connect / separate the pump impeller 31 and the turbine runner 32. When the lockup clutch 33 is engaged, the pump impeller 31 and the turbine runner 32 are directly connected, and when the lockup clutch 33 is released, the pump impeller 31 and the turbine runner 32 are separated.

  When the E / G output shaft is rotated in a state where the lockup clutch 33 is released, the pump impeller 31 rotates. When the pump impeller 31 rotates, an oil flow from the pump impeller 31 toward the turbine runner 32 is generated. This oil flow is received by the turbine runner 32 and the turbine runner 32 rotates. At this time, the amplifying action of the torque converter 3 occurs, and the turbine runner 32 generates a power larger than the power (torque) of the E / G output shaft.

  When the lockup clutch 33 is engaged, when the E / G output shaft is rotated, the E / G output shaft, the pump impeller 31 and the turbine runner 32 are rotated together.

  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 disposed so that the rotational axis of the pump impeller 31 coincides with the pump impeller 31 and is coupled to the pump impeller 31 so as not to be relatively rotatable. Accordingly, when the pump impeller 31 is rotated by the power of the engine 2, the pump shaft of the oil pump 5 is rotated and oil is discharged from the oil pump 5.

  The continuously variable transmission 4 transmits the 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 disposed in parallel with the input shaft 41. An output gear 45 is supported on the output shaft 42 so as not to be relatively rotatable.

  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 disposed on the same axis as the input shaft 41 and the output shaft 42, respectively.

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

  The primary pulley 53 is disposed so as to face the fixed sheave 61 fixed to the primary shaft 51 with the belt 55 sandwiched between the fixed sheave 61 and is supported by the primary shaft 51 so as to be movable in the axial direction but not to be relatively rotatable. 62. A piston 63 fixed to the primary shaft 51 is provided on the opposite side of the movable sheave 62 from the fixed sheave 61, and a piston chamber (oil chamber) 64 is formed between the movable sheave 62 and the piston 63. Yes.

  The secondary pulley 54 is disposed to face the fixed sheave 65 fixed to the secondary shaft 52 with the belt 55 sandwiched between the fixed sheave 65 and is supported by the secondary shaft 52 so as to be movable in the axial direction but not to be relatively rotatable. A movable sheave 66 is provided. 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.

  Although not shown, a bias spring for applying an initial clamping pressure (initial thrust) to the belt 55 is interposed between the movable sheave 66 and the piston 67. Due to the elastic force of the bias spring, the movable sheave 66 and the piston 67 are urged in a direction away from each other.

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

  Specifically, when the pulley ratio (transmission ratio) is lowered to the high side, the movable sheave 62 of the primary pulley 53 moves to the fixed sheave 61 side by controlling the supply of hydraulic oil to the piston chamber 64 of the primary pulley 53. The interval (groove width) between the fixed sheave 61 and the movable sheave 62 is reduced. Accordingly, the winding diameter of the belt 55 around the primary pulley 53 is increased, and the interval (groove width) between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 is increased. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 decreases (decreases).

  When the pulley ratio is increased to the low side, the thrust of the secondary pulley 54 with respect to the belt 55 is made larger than the thrust of the primary pulley 53 with respect to the belt 55 by controlling the supply of hydraulic oil to the piston chamber 64 of the primary pulley 53. As a result, the interval between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 is reduced, and the interval between the fixed sheave 61 and the movable sheave 62 is increased. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 is increased (increased).

  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 piston chamber 68 of the secondary pulley 54 is controlled so that a thrust according to the magnitude of the torque input to the input shaft 41 is obtained.

  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 on 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 relative to the input shaft 41, and is disposed in a space surrounded by the 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 rotational axis coincides with the axis of the primary shaft 51. A 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 collectively surround the plurality of pinion gears 75 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 coupled (coupled so as to be integrally rotatable) and a released state (off) in which the direct coupling is released by hydraulic pressure.

  The forward brake B <b> 1 is provided between the carrier 72 and a transmission case that houses the torque converter 3 and the continuously variable transmission 4, and engages (turns on) to brake the carrier 72 by hydraulic pressure, and rotates the carrier 72. It is switched to an allowable release 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 while the carrier 72 is stationary. Therefore, the rotation of the sun gear 73 is transmitted to the ring gear 74 while being reversed and decelerated. As a result, the ring gear 74 rotates, and the primary shaft 51 and the primary pulley 53 of the belt transmission mechanism 43 rotate together with the ring gear 74. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate 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 (the input gear of the differential gear 6). When the output gear 45 rotates, the drive shafts 7 and 8 extending left and right from the differential gear 6 rotate and drive wheels (not shown) rotate, so that the vehicle 1 moves forward.

  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 reversing the rotation direction. As a result, the ring gear 74 rotates in the direction opposite to that when the vehicle 1 moves forward, and the primary shaft 51 and the primary pulley 53 of the belt transmission mechanism 43 rotate together with the ring gear 74. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate 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 and 8 extending from the differential gear 6 to the left and right rotate in the opposite direction to the forward movement, and the drive wheels (not shown) rotate, whereby the vehicle 1 moves backward.

<Control device>
FIG. 3 is a block diagram showing the configuration of the CVTECU 12.

  The CVT ECU 12 controls the amount of oil supplied to the piston chamber 64 (see FIG. 2) of the primary pulley 53 for the shift control of the continuously variable transmission 4 based on the primary rotation speed, the secondary rotation speed, and the accelerator opening. Specifically, the hydraulic circuit 25 for supplying hydraulic pressure to each part of the continuously variable transmission 4 is provided with a ratio control valve (not shown) that controls the amount of oil supplied to the piston chamber 64 of the primary pulley 53. In order to control the ratio control valve, an upshift solenoid valve 26 and a downshift solenoid valve 27 are provided. The upshift solenoid valve 26 and the downshift solenoid valve 27 are duty solenoid valves that generate a signal pressure (hydraulic pressure) corresponding to the duty ratio. An upshift signal pressure generated by the upshift solenoid valve 26 and a downshift signal pressure generated by the downshift solenoid valve 27 are input to the ratio control valve, and the relative relationship between the upshift signal pressure and the downshift signal pressure is obtained. The corresponding flow rate of hydraulic oil is supplied from the ratio control valve to the piston chamber 64 of the primary pulley 53.

  The CVTECU 12 substantially includes a target value setting unit 101, an FB (feedback) controller unit 102, and a duty setting unit 103 as processing units for shift control. These processing units are realized by software by program processing or by hardware such as a logic circuit.

  In the target value setting unit 101, a target rotational speed (target value of the rotational speed input to the input shaft 41) corresponding to the accelerator opening and the vehicle speed is set. The accelerator opening is input from the engine ECU 11 (see FIG. 1) to the CVTECU 12. The vehicle speed may be calculated from the actual output rotational speed obtained by converting the frequency of the detection signal of the output rotational speed sensor 24, or may be calculated by another ECU and input from the ECU to the CVTECU 12.

  A deviation between the target rotational speed set by the target value setting section 101 and the actual input rotational speed obtained by converting the frequency of the detection signal of the input rotational speed sensor 23 is input to the FB controller section 102. In the FB controller unit 102, for example, a control instruction value corresponding to a deviation between the target rotational speed and the actual input rotational speed is set by a proportional operation, an integral operation, and a differential operation.

  The duty setting unit 103 receives the control instruction value output from the FB controller unit 102. In the duty setting unit 103, a duty ratio corresponding to the control instruction value output from the FB controller unit 102 is set according to the conversion map stored in the nonvolatile memory of the CVT ECU 12.

  The duty ratio includes a duty ratio input to the upshift solenoid valve 26 and a duty ratio input to the downshift solenoid valve 27. When the duty ratio is input to the upshift solenoid valve 26, the hydraulic pressure corresponding to the duty ratio is output from the upshift solenoid valve 26 as an upshift signal pressure, and the upshift signal pressure is input to the ratio control valve. When the duty ratio is input to the downshift solenoid valve 27, the hydraulic pressure corresponding to the duty ratio is output from the downshift solenoid valve 27 as a downshift signal pressure, and the downshift signal pressure is input to the ratio control valve. Then, hydraulic oil is supplied from the ratio control valve to the piston chamber 64 of the primary pulley 53, so that the actual input rotational speed matches the target rotational speed, and the pulley ratio of the continuously variable transmission 4 corresponds to the target rotational speed. The speed is changed so as to coincide with the pulley ratio (target pulley ratio).

<Target value setting section>
FIG. 4 is a block diagram illustrating a configuration of the target value setting unit 101. FIGS. 5A and 5B are diagrams for explaining a method of setting the target rotational speed N ′ by the target value setting unit 101. FIG. 5A is a shift diagram, FIG. (C) an example of the time change of the vehicle speed V and the hysteresis vehicle speed Vh, and (d) an example of the time change of the hysteresis target gear ratio Gh. FIGS. 6A and 6B are diagrams for explaining a method of setting the target rotational speed N ′ by the target value setting unit 101. FIG. 6A is a shift diagram, and FIG. The other example of (c) Other examples of the time change of the vehicle speed V and the hysteresis vehicle speed Vh, (d) The other example of the time change of the hysteresis target gear ratio Gh is shown.

  The target value setting unit 101 substantially includes a first hysteresis applying unit 111, a second hysteresis applying unit 112, a hysteresis target rotational speed setting unit 113, a hysteresis target speed ratio calculating unit 114, and a target rotational speed calculating unit 115. . These processing units are realized by software by program processing or by hardware such as a logic circuit.

  The first hysteresis applying unit 111 calculates a hysteresis accelerator opening Ah obtained by applying hysteresis to the accelerator opening A input from the engine ECU 11 (see FIG. 1) to the CVTECU 12.

  As shown in FIG. 5 (b), when the accelerator opening A changes within a range (within the dead zone) where the accelerator openings A1 and A2 are the lower limit and the upper limit, respectively, the hysteresis accelerator opening Ah is within the range. Constant value (for example, the median value of the range).

  As shown in FIG. 6 (b), when the accelerator opening A changes beyond the ranges where the accelerator openings A3 and A4 are lower and upper limits, respectively, the accelerator opening A is less than the accelerator openings A3 and A4. The hysteresis accelerator opening Ah becomes a constant value within the range (for example, the median value of the range) while increasing within the ranges set as the lower limit and the upper limit, respectively. When the accelerator opening A increases beyond the accelerator opening A4, the hysteresis accelerator opening Ah increases as the accelerator opening A increases until the accelerator opening A reaches the accelerator opening A6. While the degree A decreases within the ranges where the accelerator openings A5 and A6 are the lower limit and the upper limit, respectively, the hysteresis accelerator opening Ah is a constant value within the range (for example, the median value of the range). When the accelerator opening A decreases beyond the accelerator opening A5, the hysteresis accelerator opening Ah decreases as the accelerator opening A decreases until the accelerator opening A reaches the accelerator opening A3. .

  The second hysteresis applying unit 112 calculates a hysteresis vehicle speed Vh obtained by adding hysteresis to the vehicle speed V calculated from the actual output rotational speed or input from another ECU to the CVT ECU 12.

  As shown in FIG. 5C, when the vehicle speed V changes within a range (within a dead zone) where the vehicle speeds V1 and V2 are lower and upper limits, respectively, the hysteresis vehicle speed Vh is a constant value within the range (for example, Median of the range).

  As shown in FIG. 6 (c), when the vehicle speed V changes beyond the range where the vehicle speeds V3 and V4 are the lower limit and the upper limit, respectively, the vehicle speed V is within the range where the vehicle speeds V3 and V4 are the lower limit and the upper limit, respectively. The hysteresis vehicle speed Vh becomes a constant value within the range (for example, the median value of the range) while the value decreases. When the vehicle speed V decreases beyond the vehicle speed V3, the hysteresis vehicle speed Vh decreases as the vehicle speed V decreases until the vehicle speed V reaches the vehicle speed V5, and the vehicle speed V decreases to the vehicle speeds V5 and A6. While increasing within the upper limit range, the hysteresis vehicle speed Vh becomes a constant value within the range (for example, the median value of the range). When the vehicle speed V increases beyond the vehicle speed V6, the hysteresis vehicle speed Vh increases as the vehicle speed V increases until the vehicle speed V reaches the vehicle speed V4.

  The hysteresis target rotation speed setting unit 113 sets the hysteresis target rotation speed Nh corresponding to the hysteresis accelerator opening Ah and the hysteresis vehicle speed Vh based on the shift diagrams shown in FIGS. 5 (a) and 6 (a). . The shift diagram is the same as that conventionally used for controlling a continuously variable transmission, and is mapped and stored in a non-volatile memory (ROM, flash memory, EEPROM, or the like) of the CVTECU 12. Yes.

  The hysteresis target speed ratio calculation unit 114 calculates the hysteresis target speed ratio Gh from the hysteresis target speed Nh and the hysteresis vehicle speed Vh. The hysteresis target speed ratio Gh can be calculated by multiplying the hysteresis vehicle speed Vh by a coefficient determined from the final gear ratio and the like and dividing the hysteresis target rotational speed Nh by the multiplication value.

  The hysteresis target speed Nh has a hysteresis with respect to the target speed N set according to the accelerator opening A and the vehicle speed V from the shift diagram, and the hysteresis vehicle speed Vh has a hysteresis with respect to the vehicle speed V. ing. Therefore, as shown in FIG. 5 (d), the accelerator opening A changes within a range where the accelerator openings A1 and A2 are the lower limit and the upper limit, respectively, and the vehicle speed V is the lower and upper limits of the vehicle speeds V1 and V2, respectively. When changing within the range, the hysteresis target gear ratio Gh becomes a constant value. Further, as shown in FIG. 6 (d), the accelerator opening A changes beyond the ranges where the accelerator openings A3 and A4 are lower and upper limits, respectively, and the vehicle speed V is lower and lower than the vehicle speeds V3 and V4, respectively. When changing beyond the upper limit range, the hysteresis target speed ratio Gh changes within the ranges where the hysteresis target speed ratios Gh1 and Gh2 are lower and upper limits, respectively, and is calculated from the target rotational speed N and the vehicle speed V. Compared with the change of the target gear ratio G (conventional), the change width is small.

  The target rotational speed calculation unit 115 calculates the target rotational speed N ′ from the hysteresis target gear ratio Gh and the vehicle speed V. The target rotational speed N ′ can be calculated by multiplying a coefficient determined from the vehicle speed V, the hysteresis target speed ratio Gh, the final gear ratio, and the like.

<Effect>
As described above, based on the accelerator opening A, the vehicle speed V, and the shift diagram, not the target gear ratio G calculated from the target rotational speed N corresponding to the accelerator opening A and the vehicle speed V, but the target gear ratio G The hysteresis target speed ratio Gh to which hysteresis is applied is set, and the speed ratio of the continuously variable transmission 4 is changed to match the hysteresis target speed ratio Gh.

  Thereby, when the increase amount of the accelerator opening A is small and the target gear ratio G changes within the hysteresis dead band, the hysteresis target gear ratio Gh is kept constant, and the gear ratio of the continuously variable transmission 4 is kept constant. Therefore, the output rotational speed (vehicle speed) increases with high responsiveness to the increase in the input rotational speed due to the increase in the accelerator opening A. As a result, the occurrence of rubber band feeling (rubber band feel) can be suppressed, and a running feeling with a direct feeling (linear feeling) with respect to the accelerator operation can be obtained.

  When the increase amount of the accelerator opening A is large and the target gear ratio G changes beyond the dead zone of the hysteresis, the hysteresis target gear ratio Gh is continuously variable in a stepless manner according to the increase amount of the accelerator opening A. Therefore, it is possible to achieve a travel with good fuel efficiency by utilizing the continuously variable transmission while obtaining an appropriate driving force for accelerating the vehicle 1.

  Therefore, it is possible to suppress the occurrence of rubber band feeling without impairing the advantages of continuously variable transmission.

<Other configuration of target value setting unit>
FIG. 7 is a block diagram showing another configuration of the target value setting unit 101.

  The target value setting unit 101 substantially includes a target rotation number setting unit 121, a target gear ratio calculation unit 122, a hysteresis applying unit 123, and a target rotation number calculation unit 124. These processing units are realized by software by program processing or by hardware such as a logic circuit.

  The target rotational speed setting unit 121 calculates from the accelerator opening A input from the engine ECU 11 (see FIG. 1) to the CVTECU 12 and the actual output rotational speed based on the shift map, or the vehicle speed input from another ECU to the CVTECU 12. A target rotational speed N corresponding to V is set. The shift diagram is the same as that conventionally used for controlling the continuously variable transmission, and is mapped and stored in the non-volatile memory of the CVTECU 12.

  The target gear ratio calculation unit 122 calculates the target gear ratio G from the target rotational speed N and the vehicle speed V. The target gear ratio G can be calculated by multiplying the vehicle speed V by a coefficient determined from the final gear ratio and the like and dividing the target rotational speed N by the multiplication value.

  The hysteresis applying unit 123 calculates a hysteresis target speed ratio Gh obtained by adding hysteresis to the target speed ratio G. If the accelerator opening A and the vehicle speed V input to the target value setting unit 101 having the configuration shown in FIG. 4 and the target value setting unit 101 having the configuration shown in FIG. The hysteresis target speed ratio Gh substantially coincides with the hysteresis target speed ratio Gh calculated by the hysteresis target speed ratio calculation unit 114 shown in FIG.

  The target rotational speed calculation unit 124 calculates the target rotational speed N ′ from the hysteresis target gear ratio Gh and the vehicle speed V. The target rotational speed N ′ can be calculated by multiplying a coefficient determined from the vehicle speed V, the hysteresis target speed ratio Gh, the final gear ratio, and the like.

  Also with the configuration shown in FIG. 7, the same operational effects as in the configuration shown in FIG. 4 can be obtained.

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

  For example, each of the sensors described above is merely an example of a sensor related to the present invention, and other sensors may be connected to the engine ECU 11 and the CVTECU 12.

  Further, some or all of the functions of the engine ECU 11 and the CVTECU 12 may be integrated into one ECU.

  The present invention can also be applied to a control device for a power split type continuously variable transmission. The power-dividing continuously variable transmission is a belt-type continuously variable transmission mechanism that shifts the power steplessly by changing the gear ratio, and a constant gear shift that shifts the power at a constant gear ratio. And a transmission capable of dividing and transmitting the power of the drive source into two systems.

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

1 vehicle 4 continuously variable transmission 12 CVTECU (control device, accelerator opening acquisition means, vehicle speed acquisition means)
101 Target value setting unit (shift diagram storage means, hysteresis target speed ratio setting means)
102 FB controller (speed ratio changing means)
103 Duty setting section (speed ratio changing means)

Claims (1)

A control device for a continuously variable transmission mounted on a vehicle,
Accelerator opening obtaining means for obtaining the accelerator opening;
Vehicle speed acquisition means for acquiring the vehicle speed of the vehicle;
Shift diagram storage means for storing a shift diagram that defines the relationship between the accelerator opening and the vehicle speed and the target value of the input rotational speed input to the continuously variable transmission;
Based on the accelerator opening obtained by the accelerator opening obtaining means and the vehicle speed obtained by the vehicle speed obtaining means, hysteresis is given to the target gear ratio determined from the accelerator opening, the vehicle speed, and the shift diagram. Hysteresis target speed ratio setting means for setting the hysteresis target speed ratio,
And a gear ratio changing means for changing the gear ratio of the continuously variable transmission so as to coincide with the hysteresis target gear ratio.

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