JP7158817B2 - control device for continuously variable transmission - Google Patents

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 vehicles equipped with a CVT, the ECU (Electronic Control Unit) memory for controlling the gear ratio defines the relationship between the accelerator opening (accelerator pedal depression amount) and vehicle speed and target rotation speed. A shift map is stored. Based on this shift map, a target rotation speed is set according to the accelerator opening and the vehicle speed, and the gear ratio is controlled so that the input rotation speed input to the CVT matches the target rotation speed. As a result, the gear ratio can be changed continuously according to changes in the degree of accelerator opening and vehicle speed so that the engine speed falls within the high-efficiency speed range. Good running can be realized.

JP 2010-112397 A

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

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device for a continuously variable transmission that can suppress the occurrence of rubber band feeling without impairing the advantages of the continuously variable transmission.

In order to achieve the above object, a control device for a continuously variable transmission according to the present invention is a control device for a continuously variable transmission mounted on a vehicle, comprising: accelerator opening acquisition means for acquiring an accelerator opening; a vehicle speed acquiring means for acquiring the vehicle speed of the vehicle; a gear shifting diagram storage means for storing a gear shifting diagram that defines the relationship between the accelerator opening degree and the vehicle speed and the target value of the input rotation 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 added to a target gear ratio determined from the accelerator opening, the vehicle speed, and the shift map. It includes hysteresis target gear ratio setting means for setting a target gear ratio, and gear ratio changing means for changing the gear ratio of the continuously variable transmission so as to match the hysteresis target gear ratio.

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

On the other hand, according to the configuration according to the present invention, the hysteresis in which hysteresis is added to the target gear ratio is not the target gear ratio according to the target rotation speed determined from the current accelerator opening, vehicle speed, and shift map. A target transmission ratio is set and the transmission ratio is changed to match the hysteresis transmission ratio.

As a result, when the amount of increase in the accelerator opening is small and the target gear ratio changes within the hysteresis dead zone, the hysteresis target gear ratio is kept constant, and the gear ratio of the continuously variable transmission is kept constant. The output rotation speed (vehicle speed) rises with good responsiveness to the increase in the input rotation speed due to the increase in the accelerator opening. As a result, it is possible to suppress the occurrence of rubber band feeling (rubber band feel), and it is possible to obtain a driving feeling with a direct feeling (linear feeling) in response to accelerator operation.

Further, when the amount of increase in accelerator opening is large and the target gear ratio changes beyond the hysteresis dead zone, the hysteresis target gear ratio changes steplessly and continuously according to the amount of increase in accelerator opening. Therefore, it is possible to obtain a suitable driving force for accelerating the vehicle, and to realize fuel-efficient running by making use of the continuously variable transmission.

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

The hysteresis target gear ratio setting means includes target rotation speed setting means for setting a target rotation speed according to the accelerator opening acquired by the accelerator opening acquisition means and the vehicle speed acquired by the vehicle speed acquisition means according to a shift map; Calculation means for calculating a target gear ratio from the vehicle speed acquired by the acquisition means and the target rotation speed set by the target rotation speed setting means; and a hysteresis imparting means for setting a ratio, and when the accelerator opening changes beyond the hysteresis dead zone, the hysteresis target gear ratio is set according to the increase amount of the accelerator opening obtained by the accelerator opening obtaining means. Set so that it changes steplessly and continuously.

According to the present invention, rubber band feeling can be suppressed without impairing the advantage of continuously variable transmission.

1 is a diagram showing the configuration of a main part of a vehicle equipped with a control device according to an embodiment of the invention; FIG. 1 is a skeleton diagram showing the configuration of a drive system of a vehicle; FIG. 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. 4A and 4B are diagrams for explaining a method of setting a target rotation speed by a target value setting unit, including (a) a shift map, (b) an example of temporal changes in an accelerator opening A and a hysteresis accelerator opening Ah, and (c) vehicle speed; An example of time change of V and hysteresis vehicle speed Vh, and (d) an example of time change of hysteresis target gear ratio Gh are shown. 4A and 4B are diagrams for explaining a method of setting a target rotation speed N′ by a target value setting unit 101, and are (a) a shift map, and (b) another example of temporal changes in the accelerator opening A and the hysteresis accelerator opening Ah. , (c) another example of time change of vehicle speed V and hysteresis vehicle speed Vh, and (d) another example of time change of hysteresis target gear ratio Gh. It is a block diagram which shows the other structure of a target value setting part.

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Main parts of the vehicle>
FIG. 1 is a diagram showing the configuration of a main part of a vehicle 1 equipped with a control device according to an embodiment of the invention.

A vehicle 1 is an automobile having an engine 2 as a drive source. The output of the engine 2 is transmitted to 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) for injecting fuel into the intake air, and a spark plug for generating electrical discharge in the combustion chamber. It is The engine 2 is also provided with a starter for starting the engine.

The vehicle 1 is equipped with a plurality of ECUs (Electronic Control Units) each including a CPU, a ROM, a RAM, and the like. The multiple ECUs include an engine ECU 11 and a CVTECU 12 . Each ECU is connected so as to enable two-way communication by 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 outputs a detection signal corresponding to the amount of operation 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, when the accelerator pedal is not depressed to 0%, and when the accelerator pedal is fully depressed. The accelerator opening is calculated as a percentage with the time when the engine is closed as 100%.

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 to start, stop, and adjust the output of the engine 2 based on information obtained from detection signals of various sensors and/or various information input from other ECUs. It controls electronic throttle valves, injectors and spark plugs.

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

Input rotation speed sensor 23 outputs, for example, a pulse signal synchronized with the rotation of input shaft 41 (see FIG. 2) of 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, which 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 the actual output rotation speed, which is the actual rotation speed of the output shaft 42 .

The CVTECU 12 controls each part of the continuously variable transmission 4 for 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. It controls various valves and the like included in the hydraulic circuit 25 for supplying hydraulic pressure.

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

The torque converter 3 has 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 about the same rotational axis as the E/G output shaft. ing. The turbine runner 32 is rotatably provided around the same rotational 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 while the lockup clutch 33 is released, the pump impeller 31 rotates. Rotation of the pump impeller 31 causes a flow of oil from the pump impeller 31 towards 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 lockup 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 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 arranged so that the axis of rotation coincides with the pump impeller 31 and is connected to the pump impeller 31 so as not to rotate relative to it. 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 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 integrally rotatable around the same rotational axis as the turbine runner 32 .

The output shaft 42 is arranged parallel to the input shaft 41 . An output gear 45 is supported on the output shaft 42 so as not to rotate relative to it.

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 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 arranged to face a fixed sheave 61 fixed to the primary shaft 51 with a belt 55 interposed therebetween. 62. A piston 63 fixed to the primary shaft 51 is provided on the opposite side of the movable sheave 62 to the fixed sheave 61 , and a piston chamber (oil chamber) 64 is formed between the movable sheave 62 and the piston 63 . there is

The secondary pulley 54 is arranged opposite to a fixed sheave 65 fixed to the secondary shaft 52 with the belt 55 interposed therebetween, and is supported by the secondary shaft 52 so as to be movable in the axial direction thereof and not 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 is interposed between the movable sheave 66 and the piston 67 to apply initial clamping pressure (initial thrust) to the belt 55 . The elastic force of the bias spring urges the movable sheave 66 and the piston 67 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 to change the groove widths of the primary pulley 53 and the secondary pulley 54. The pulley ratio is continuously and steplessly changed.

Specifically, when the pulley ratio (gear ratio) is lowered to the high side, the movable sheave 62 of the primary pulley 53 moves toward the fixed sheave 61 by controlling the supply of hydraulic oil to the piston chamber 64 of the primary pulley 53 . , the gap (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 increases, and the gap (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 (becomes smaller).

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

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

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.

Planetary gear mechanism 71 includes carrier 72 , sun gear 73 and ring gear 74 .

The carrier 72 is fitted onto the input shaft 41 so as to be relatively rotatable. Carrier 72 rotatably supports a plurality of pinion gears 75 . A 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 it, 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 rotational axis coincides with the axial center 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 by hydraulic pressure between an engaged state (ON) in which the carrier 72 and the sun gear 73 are directly connected (rotatably coupled together) and a released state (OFF) in which the direct connection is released.

The forward brake B1 is provided between the carrier 72 and the transmission case that houses the torque converter 3 and the continuously variable transmission 4. The forward brake B1 is hydraulically applied to brake the carrier 72 (on) and prevent the carrier 72 from rotating. It is switched to the permissive 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 remains stationary. Therefore, the rotation of the sun gear 73 is reversed and transmitted to the ring gear 74 at a reduced speed. 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 . 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 . 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 drive wheels (not shown) rotate, thereby causing the vehicle 1 to move 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 engine 2 is input to input shaft 41 , carrier 72 and sun gear 73 rotate together with 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 the forward movement of the vehicle 1 , and the primary shaft 51 and the primary pulley 53 of the belt transmission mechanism 43 rotate integrally with the ring gear 74 . 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 . 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 laterally from the differential gear 6 rotate in a direction opposite to the forward direction, and drive wheels (not shown) rotate, thereby causing the vehicle 1 to move backward.

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

The CVTECU 12 controls the amount of oil supplied to the piston chamber 64 (see FIG. 2) of the primary pulley 53 for the speed change control of the continuously variable transmission 4 based on the primary rotation speed, secondary rotation speed, and 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) for controlling the amount of oil supplied to the piston chamber 64 of the primary pulley 53. An upshift solenoid valve 26 and a downshift solenoid valve 27 are provided to control the ratio control valves thereof. The upshift solenoid valve 26 and the downshift solenoid valve 27 are duty solenoid valves that generate a signal pressure (hydraulic pressure) according to a duty ratio. The upshift signal pressure generated by the upshift solenoid valve 26 and the downshift signal pressure generated by the downshift solenoid valve 27 are input to the ratio control valve. Hydraulic oil having a corresponding flow rate 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 section 101, an FB (feedback) controller section 102, and a duty setting section 103 as processing sections for shift control. These processing units are realized in software by program processing, or in hardware such as logic circuits.

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

The deviation between the target rotation speed set by the target value setting unit 101 and the actual input rotation speed obtained by converting the frequency of the detection signal of the input rotation speed sensor 23 is input to the FB controller unit 102 . In the FB controller unit 102, for example, a control instruction value is set according to the deviation between the target rotation speed and the actual input rotation speed by proportional action, integral action, and differential action.

A control instruction value output from the FB controller unit 102 is input to the duty setting unit 103 . The duty setting unit 103 sets a duty ratio according to the control instruction value output from the FB controller unit 102 according to the conversion map stored in the nonvolatile memory of the CVTECU 12 .

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

<Target value setting part>
FIG. 4 is a block diagram showing the configuration of the target value setting unit 101. As shown in FIG. 5A and 5B are diagrams for explaining a method of setting the target rotation speed N′ by the target value setting unit 101, and include (a) a shift map, and (b) changes over time of the accelerator opening A and the hysteresis accelerator opening Ah. An example, (c) an example of temporal changes in vehicle speed V and hysteresis vehicle speed Vh, and (d) an example of temporal changes in hysteresis target gear ratio Gh are shown. 6A and 6B are diagrams for explaining a method of setting the target rotation speed N′ by the target value setting unit 101. (a) Shift map, (b) Time change of the accelerator opening A and the hysteresis accelerator opening Ah. (c) another example of time change of vehicle speed V and hysteresis vehicle speed Vh, and (d) another example of time change of hysteresis target gear ratio Gh.

The target value setting section 101 substantially includes a first hysteresis provision section 111, a second hysteresis provision section 112, a hysteresis target rotation speed setting section 113, a hysteresis target gear ratio calculation section 114, and a target rotation speed calculation section 115. . These processing units are realized in software by program processing, or in hardware such as logic circuits.

The first hysteresis imparting unit 111 calculates a hysteresis accelerator opening Ah obtained by imparting 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) having the lower and upper limits of the accelerator openings A1 and A2, respectively, the hysteresis accelerator opening Ah is within the range. is a 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 having the lower and upper limits of the accelerator openings A3 and A4, respectively, the accelerator opening A exceeds the accelerator openings A3 and A4. While increasing within the respective lower and upper limits, the hysteresis accelerator opening Ah becomes a constant value within the range (for example, the median value of the range). Then, when the accelerator opening degree A increases beyond the accelerator opening degree A4, the hysteresis accelerator opening degree Ah increases as the accelerator opening degree A increases until the accelerator opening degree A reaches the accelerator opening degree A6. While the degree A decreases within the ranges having the lower and upper limits of the accelerator openings A5 and A6, respectively, the hysteresis accelerator opening Ah becomes 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 imparting unit 112 calculates a hysteresis vehicle speed Vh by imparting hysteresis to the vehicle speed V calculated from the actual output rotation speed or input to the CVTECU 12 from another ECU.

As shown in FIG. 5(c), when the vehicle speed V changes within the range (within the dead zone) having the lower and upper limits of the vehicle speeds V1 and V2, 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 ranges having the lower and upper limits of vehicle speeds V3 and V4, respectively, the vehicle speed V changes within the ranges having the lower and upper limits of vehicle speeds V3 and V4, respectively. , 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 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. While increasing within the upper limit range, the hysteresis vehicle speed Vh is 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.

A hysteresis target rotation speed setting unit 113 sets a hysteresis target rotation speed Nh according to the hysteresis accelerator opening Ah and the hysteresis vehicle speed Vh based on the shift map shown in FIGS. 5(a) and 6(a). . The shift map is similar to one that has been widely used for control of a continuously variable transmission, and is mapped and stored in a non-volatile memory (ROM, flash memory, EEPROM, etc.) of the CVTECU 12. there is

A hysteresis target gear ratio calculation unit 114 calculates a hysteresis target gear ratio Gh from the hysteresis target rotation speed Nh and the hysteresis vehicle speed Vh. The hysteresis target gear ratio Gh can be calculated by multiplying the hysteresis vehicle speed Vh by a coefficient determined from the final gear ratio, etc., and dividing the hysteresis target rotation speed Nh by the multiplied value.

The hysteresis target rotation speed Nh has hysteresis with respect to the target rotation speed N that is set according to the accelerator opening A and the vehicle speed V from the shift map, and the hysteresis vehicle speed Vh has hysteresis with respect to the vehicle speed V. ing. Therefore, as shown in FIG. 5(d), the accelerator opening A changes within a range in which the accelerator openings A1 and A2 are the lower and upper limits, respectively, and the vehicle speed V is set to the lower and upper limits of the vehicle speeds V1 and V2, respectively. When it changes 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 in which the accelerator openings A3 and A4 are the lower and upper limits, respectively, and the vehicle speed V is changed to the lower and upper limits of the vehicle speeds V3 and V4, respectively. When the hysteresis target gear ratio Gh changes beyond the upper limit range, the hysteresis target gear ratio Gh changes within the lower limit and upper limit ranges of the hysteresis target gear ratios Gh1 and Gh2, respectively, and is calculated from the target rotation speed N and the vehicle speed V. The range of change is small compared to the change in the target gear ratio G (conventional).

A target rotation speed calculation unit 115 calculates a target rotation speed N′ from the hysteresis target gear ratio Gh and the vehicle speed V. FIG. The target rotation speed N' can be calculated by multiplying a coefficient determined from the vehicle speed V, the hysteresis target gear 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 map, instead of the target gear ratio G calculated from the target rotation speed N corresponding to the accelerator opening A and the vehicle speed V, A hysteresis target gear ratio Gh to which hysteresis is added is set, and the gear ratio of the continuously variable transmission 4 is changed so as to match the hysteresis target gear ratio Gh.

As a result, when the amount of increase in the accelerator opening A is small and the target gear ratio G changes within the hysteresis dead zone, 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 rotation speed (vehicle speed) increases with good response to the increase in the input rotation speed due to the increase in the accelerator opening A. As a result, it is possible to suppress the occurrence of rubber band feeling (rubber band feel), and it is possible to obtain a driving feeling with a direct feeling (linear feeling) in response to accelerator operation.

Further, when the amount of increase in the accelerator opening A is large and the target gear ratio G changes beyond the hysteresis dead zone, the hysteresis target gear ratio Gh is continuously stepless according to the amount of increase in the accelerator opening A. , it is possible to obtain an appropriate driving force for accelerating the vehicle 1 while realizing fuel-efficient running utilizing the continuously variable transmission.

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

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

The target value setting section 101 substantially includes a target rotational speed setting section 121 , a target gear ratio calculating section 122 , a hysteresis applying section 123 and a target rotational speed calculating section 124 . These processing units are realized in software by program processing, or in hardware such as logic circuits.

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

A target gear ratio calculation unit 122 calculates a target gear ratio G from the target rotation speed N and the vehicle speed V. FIG. The target gear ratio G can be calculated by multiplying the vehicle speed V by a coefficient determined from the final gear ratio, etc., and dividing the target rotation speed N by the multiplied value.

A hysteresis imparting unit 123 calculates a hysteresis target gear ratio Gh by imparting hysteresis to the target gear ratio G. FIG. If the accelerator opening A and the vehicle speed V input to the target value setting unit 101 configured as shown in FIG. 4 and the target value setting unit 101 configured as shown in FIG. The hysteresis target gear ratio Gh substantially matches the hysteresis target gear ratio Gh calculated by the hysteresis target gear ratio calculation section 114 shown in FIG.

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

The configuration shown in FIG. 7 can also provide the same effects as the configuration shown in FIG.

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

For example, the sensors described above are merely examples of sensors related to the present invention, and engine ECU 11 and CVTECU 12 may be connected to other sensors.

Moreover, 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. A power split type continuously variable transmission consists of a belt-type continuously variable transmission mechanism that changes the power continuously by changing the gear ratio, and a constant speed change mechanism that changes the power at a constant gear ratio. mechanism, and is capable of transmitting the power of the driving source by dividing it into two systems.

In addition, various design changes can be made to the above 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 gear ratio setting means)
102 FB controller section (gear ratio changing means)
103 duty setting unit (gear ratio changing means)

Claims (1)

A control device for a continuously variable transmission mounted on a vehicle,
accelerator opening acquisition means for acquiring the accelerator opening;
vehicle speed acquisition means for acquiring the vehicle speed of the vehicle;
a shift map storage means for storing a shift map that defines the relationship between the accelerator opening degree and the vehicle speed and the target value of the input rotation speed input to the continuously variable transmission;
Based on the accelerator opening acquired by the accelerator opening acquiring means and the vehicle speed acquired by the vehicle speed acquiring means, hysteresis is imparted to a target gear ratio determined from the accelerator opening, the vehicle speed, and the shift map. a hysteresis target gear ratio setting means for setting the hysteresis target gear ratio;
gear ratio changing means for changing the gear ratio of the continuously variable transmission so as to match the hysteresis target gear ratio;
The hysteresis target gear ratio setting means includes:
target rotation speed setting means for setting a target rotation speed according to the accelerator opening acquired by the accelerator opening acquisition means and the vehicle speed acquired by the vehicle speed acquisition means according to the shift map;
calculation means for calculating a target gear ratio from the vehicle speed acquired by the vehicle speed acquisition means and the target rotation speed set by the target rotation speed setting means;
hysteresis imparting means for imparting hysteresis to the target gear ratio calculated by the calculating means and setting the hysteresis target gear ratio;
The hysteresis imparting means maintains the hysteresis target gear ratio constant when the target gear ratio calculated by the calculating means changes within the dead zone of the hysteresis, and the target gear ratio calculated by the calculating means is kept constant. When the change exceeds the dead band of the hysteresis, the hysteresis target gear ratio is changed steplessly and continuously according to the increase amount of the accelerator opening acquired by the accelerator opening acquiring means. A controller that sets a target gear ratio.

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