JP7003327B2 - Vehicle control device and vehicle control method - Google Patents

Description

The present invention relates to a vehicle control device and a vehicle control method.

JP2006-90474A discloses a belt continuously variable transmission that changes the gear ratio by changing the pulley differential thrust with respect to the target stroke speed according to the rotation speed of the primary pulley.

In JP2006-90474A, parameters other than the rotation speed of the primary pulley are not taken into consideration when changing the gear ratio. However, as a result of the study, the present inventors have found that parameters other than the rotation speed of the primary pulley affect the relationship between the target stroke speed and the differential thrust. Therefore, it is considered that there is room for improvement in setting the differential thrust with respect to the target stroke speed.

The present invention has been made in view of such technical problems, and an object of the present invention is to enable accurate setting of differential thrust with respect to a target stroke speed.

According to an aspect of the present invention, the control device for a vehicle including a belt stepless transmission is provided by the belt stepless transmission with reference to a plurality of maps showing the relationship between a target stroke speed and a differential thrust. It has a control unit that controls the speed change of the variator, and the plurality of maps include a downshift map that is referred to when the variator is downshifted, and an upshift map that is referred to when the variator is upshifted. A vehicle control device is provided in which the inclination of the target stroke speed with respect to the differential thrust in the downshift map is larger than the inclination of the target stroke speed with respect to the differential thrust in the upshift map.

Further, according to another aspect of the present invention, it is a control method of a vehicle provided with a belt continuously variable transmission, and the belt continuously variable transmission is described with reference to a plurality of maps showing the relationship between a target stroke speed and a differential thrust. When the shift control of the variator possessed by the machine is performed and the variator is downshifted, the target stroke for the differential thrust is higher than the upshift map referred to when the variator is upshifted among the plurality of maps. A vehicle control method is provided that refers to a downshift map with a large speed gradient.

According to these aspects, the map to be referred to among the plurality of maps showing the relationship between the target stroke speed and the differential thrust is changed depending on whether the upshift is performed or the downshift is performed. Therefore, the differential thrust for obtaining the target stroke speed can be set with high accuracy.

FIG. 1 is a schematic configuration diagram of a vehicle according to an embodiment of the present invention. FIG. 2 is a flowchart showing the processing contents of shift control. FIG. 3 is a diagram comparing the slope of the target stroke speed with respect to the differential thrust in the case of downshift and the case of upshift. FIG. 4 is a diagram for explaining the relationship between the input torque to the variator and the slope of the target stroke speed with respect to the differential thrust. FIG. 5A is a map to be referred to when shifting DL at a vehicle speed of 30 km / h. FIG. 5B is a map to be referred to when shifting DL at a vehicle speed of 60 km / h. FIG. 5C is a map to be referred to when shifting DL at a vehicle speed of 100 km / h. FIG. 6A is a map to be referred to when shifting to LD at a vehicle speed of 30 km / h. FIG. 6B is a map to be referred to when shifting to LD at a vehicle speed of 60 km / h. FIG. 6C is a map to be referred to when shifting to LD at a vehicle speed of 100 km / h. FIG. 7A is a map to be referred to when shifting to LFUS at a vehicle speed of 75 km / h. FIG. 7B is a map to be referred to when shifting to LFUS at a vehicle speed of 85 km / h. FIG. 7C is a map to be referred to when shifting to LFUS at a vehicle speed of 115 km / h.

Hereinafter, the vehicle 100 according to the embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram of the vehicle 100. As shown in FIG. 1, the vehicle 100 includes an engine 5 as a drive source and an automatic transmission 1 as a belt continuously variable transmission that shifts the rotation of the engine 5 and transmits the rotation to the drive wheels 50.

The automatic transmission 1 includes a torque converter 6, a variator 20, a forward / backward switching mechanism 7, and a hydraulic control circuit 11.

The torque converter 6 has a lockup clutch 6c. The lockup clutch 6c is engaged by supplying a lockup pressure from the hydraulic control circuit 11. When the lockup clutch 6c is engaged, the input shaft 60 and the output shaft 61 of the torque converter 6 are directly connected, and the input shaft 60 and the output shaft 61 rotate at the same speed.

The variator 20 has a primary pulley 2 and a secondary pulley 3 arranged so that the V grooves are aligned, and a belt 4 spanned by the V grooves of the pulleys 2 and 3.

The engine 5 is arranged coaxially with the primary pulley 2, and a torque converter 6 and a forward / backward switching mechanism 7 are provided between the engine 5 and the primary pulley 2 in order from the engine 5 side.

The forward / backward switching mechanism 7 has a double pinion planetary gear set 7a as a main component, the sun gear thereof is coupled to the engine 5 via a torque converter 6, and the carrier is coupled to the primary pulley 2. The forward / backward switching mechanism 7 further includes a forward clutch 7b that directly connects the sun gear and the carrier of the double pinion planetary gear set 7a, and a reverse brake 7c that fixes the ring gear. When the forward clutch 7b is engaged, the input rotation from the engine 5 via the torque converter 6 is transmitted to the primary pulley 2 as it is, and when the reverse brake 7c is engaged, the input rotation from the engine 5 via the torque converter 6 is reversed. Is transmitted to the primary pulley 2.

The forward clutch 7b is engaged by supplying clutch pressure from the hydraulic control circuit 11 when the forward travel mode is selected by the shift lever 40. The reverse brake 7c is engaged by supplying a brake pressure from the hydraulic control circuit 11 when the reverse travel mode is selected by the shift lever 40.

The rotation of the primary pulley 2 is transmitted to the secondary pulley 3 via the belt 4, and the rotation of the secondary pulley 3 is transmitted to the drive wheels 50 via the output shaft 8, the gear set 9, and the differential gear device 10.

In order to make it possible to change the gear ratio between the primary pulley 2 and the secondary pulley 3 during the above power transmission, one of the conical plates forming the V groove of the primary pulley 2 and the secondary pulley 3 is fixed to the conical plates 2a and 3a. The other is a movable conical plate 2b or 3b that can be displaced in the axial direction.

These movable conical plates 2b and 3b are urged toward the fixed conical plates 2a and 3a by supplying the primary pulley pressure and the secondary pulley pressure to the primary pulley chamber 2c and the secondary pulley chamber 3c, whereby the belt 4 is conical. Power is transmitted between the primary pulley 2 and the secondary pulley 3 by frictionally engaging with the plate.

When shifting, the width of the V-grooves of both pulleys 2 and 3 is changed by the differential pressure between the primary pulley pressure and the secondary pulley pressure generated according to the target gear ratio, and the belt 4 is wound around the pulleys 2 and 3. The target gear ratio is achieved by continuously changing the arc diameter. In the following, the difference between the thrust acting on the movable conical plate 2b due to the primary pulley pressure and the thrust acting on the movable conical plate 3b due to the secondary pulley pressure is referred to as differential thrust.

The lockup pressure, clutch pressure, brake pressure, primary pulley pressure, and secondary pulley pressure are controlled by the hydraulic control circuit 11 based on the control signal from the controller 12.

The hydraulic control circuit 11 includes a plurality of oil passages and a plurality of solenoid valves. The hydraulic pressure control circuit 11 switches the hydraulic pressure supply path based on the control signal from the controller 12, adjusts the pressure of the hydraulic oil supplied from the oil pump 30, and generates the required hydraulic pressure, which is automatically transmitted. Supply to each part of 1.

The oil pump 30 is driven by using a part of the power of the engine 5. The oil pump 30 may be an electric oil pump.

The controller 12 is composed of a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, a bus connecting these, and the like. The controller 12 controls each part of the vehicle 100 by the CPU reading and executing the program stored in the ROM.

The controller 12 has the rotational speed and torque of the engine 5, the engaged state of the lockup clutch 6c, the gear ratio of the variator 20, the forward clutch 7b and the reverse brake 7c based on the signals from various sensors that detect the state of each part of the vehicle 100. It controls the fastening state etc. in an integrated manner.

The controller 12 has a signal from the accelerator opening sensor 21 that detects the opening APO of the accelerator pedal 41, a signal from the brake hydraulic pressure sensor 22 that detects the brake hydraulic pressure BRP corresponding to the operation amount of the brake pedal 42, and a shift. A signal from the inhibitor switch 23 that detects the position of the lever 40, a signal from the rotation speed sensor 13 that detects the rotation speed Nin on the input side (engine 5 side) of the forward / backward switching mechanism 7, and an output side of the forward / backward switching mechanism 7. A signal from the rotation speed sensor 14 that detects the rotation speed Nout of the (variator 20 side), a signal from the vehicle speed sensor 15 that detects the vehicle speed VSS, a signal from the rotation speed sensor 16 that detects the rotation speed Ne of the engine 5, a primary A signal from the pressure sensor 17 for detecting the pulley pressure, a signal from the pressure sensor 18 for detecting the secondary pulley pressure, and the like are input.

By the way, as described above, the controller 12 controls the gear ratio of the variator 20. Here, in the shifting of the variator 20, it is also important to control the time until the shifting ratio reaches the target shifting ratio. Therefore, the controller 12 also controls the stroke speeds of the pulleys 2 and 3 until the gear ratio of the variator 20 reaches the target gear ratio.

Hereinafter, the shift control of the variator 20 executed by the control unit of the controller 12 will be described with reference to FIG. 2. The control unit is a virtual unit having a function of executing shift control of the controller 12.

In step S11, the control unit of the controller 12 detects the shift scene of the vehicle 100 based on the signals from various sensors input to the controller 12.

The shift scene includes, for example, a shift due to a change in the selection range by the shift lever 40, a shift due to a change in the accelerator pedal opening APO, a shift due to a brake ON / OFF, a shift due to a change in the vehicle speed VSS, and the like.

In step S12, the control unit of the controller 12 determines the target gear ratio and the target stroke speed of the variator 20 according to the vehicle speed VSS, the accelerator pedal opening APO, and the like.

In step S13, the control unit of the controller 12 refers to a map for executing the shift of the variator 20 from a plurality of maps showing the relationship between the target stroke speed of the variator 20 and the differential thrust according to the detected shift scene. Select.

As described above, the controller 12 controls the primary pulley pressure and the secondary pulley pressure by the hydraulic control circuit 11 to stroke the pulleys 2 and 3, and changes the width of each V groove.

Here, as a result of the study, the present inventors have determined that the relationship between the target stroke speeds of the pulleys 2 and 3 and the differential thrust until the target gear ratio is reached is the case of upshifting and the case of downshifting, as shown in FIG. I found that it was different from the case of shift.

More specifically, on the left side of FIG. 3, a downshift showing the relationship between the target stroke speed and the differential thrust when the primary pulley 2 is experimentally fixed and the secondary pulley pressure is increased to shift from Mid to Low. A map and a downshift map showing the relationship between the target stroke speed and the differential thrust when shifting from Hi to MId are shown.

Further, on the right side of FIG. 3, there is an upshift map showing the relationship between the target stroke speed and the differential thrust when the secondary pulley 3 is experimentally fixed and the primary pulley pressure is increased to shift from Low to Mid. , An upshift map showing the relationship between the target stroke speed and the differential thrust when shifting from MId to Hi is shown.

As shown by the arrows in FIG. 3, when the downshift map and the upshift map in the same shift region are compared, the slope of the target stroke speed with respect to the differential thrust in the downshift map is the slope of the target stroke speed with respect to the differential thrust in the upshift map. It can be seen that it is larger than the inclination. On the other hand, the difference in the slope of the target stroke speed with respect to the differential thrust due to the difference in the shift region is slight. The slope of the target stroke speed with respect to the differential thrust means the slope of the graph when the differential thrust is on the horizontal axis and the target stroke speed is on the vertical axis.

In the present embodiment, based on the above findings, as a map showing the relationship between the target stroke speed and the differential thrust referred to by the control unit when executing the shift control, at least the downshift map referred to when downshifting is performed. , An upshift map to be referenced when performing an upshift, and multiple maps including are set.

The control unit of the controller 12 selects a downshift map as a reference map when the shift scene detected in step S11 is downshift, and selects an upshift map as a reference map when the shift scene is upshift. do.

Further, as shown in FIG. 4, the present inventors have found that the smaller the input torque to the variator 20, the larger the slope of the target stroke speed with respect to the differential thrust even in the downshift. In addition, "the input torque is small" means that the input torque is on the minus side.

This tendency is, for example, a map showing the relationship between the target stroke speed and the differential thrust in the case of downshift (CD shift) during coastal driving where the input torque is negative, and down during normal driving where the input torque is close to zero. This is particularly remarkable when compared with the map showing the relationship between the target stroke speed and the differential thrust in the case of the DL shift, which is a shift.

Therefore, in the present embodiment, based on the above findings, as a downshift map, for example, a downshift map referred to in the case of CD shifting, a downshift map referred to in the case of DL shifting, and an input torque are positive. A downshift map to be referred to in the case of a certain kickdown (KD shift) is set. The control unit of the controller 12 selects a map according to the shift scene.

Further, as shown in FIG. 4, the present inventors have found that the smaller the input torque to the variator 20, the larger the slope of the target stroke speed with respect to the differential thrust, even in the case of upshifting.

This tendency can be seen in, for example, a map showing the relationship between the target stroke speed and the differential thrust in the case of DSTep shifting simulating a stepped shifting in which the input torque is positive, and an upshift during normal driving in which the input torque is close to zero. This is particularly remarkable when compared with a map showing the relationship between the target stroke speed and the differential thrust in the case of a certain LD shift.

Therefore, in the present embodiment, based on the above findings, as the upshift map, for example, the upshift map referred to in the case of DSTep shift, the upshift map referred to in the case of LD shift, and the input torque are negative. An upshift map to be referred to in the case of an upshift (LFUS shift) due to a foot release from a certain accelerator pedal 41 is set. The control unit of the controller 12 selects a map according to the shift scene. The LFUS shift may be executed, for example, when traveling downhill.

Furthermore, the present inventors have found that in the case of LFUS shifting, the slope of the target stroke speed with respect to the differential thrust changes with time.

Therefore, in the present embodiment, as a map to be referred to when the shift scene is LFUS shift, as shown in FIG. 4, a map to be referred to in the first period after the accelerator pedal 41 is released from the foot and after the first period has elapsed. The map to be referred to in the second period of is set.

Further, the slope of the target stroke speed with respect to the differential thrust also differs depending on the vehicle speed VSS.

For example, FIG. 5A shows a target stroke speed for a differential thrust at a vehicle speed of 30 km / h, and FIG. 5B shows a target stroke speed for a differential thrust at a vehicle speed of 60 km / h. FIG. 5C shows the target stroke speed with respect to the differential thrust when the vehicle speed is changed by DL at a vehicle speed of 100 km / h.

Further, FIG. 6A shows a target stroke speed for a differential thrust when shifting to LD at a vehicle speed of 30 km / h, and FIG. 6B shows a target stroke speed for a differential thrust when shifting to LD at a vehicle speed of 60 km / h. Shown, FIG. 6C shows a target stroke speed with respect to a differential thrust when shifting to LD at a vehicle speed of 100 km / h.

Further, FIG. 7A shows a target stroke speed for a differential thrust when shifting to LFUS at a vehicle speed of 75 km / h, and FIG. 7B shows a target stroke speed for a differential thrust when shifting to LFUS at a vehicle speed of 85 km / h. FIG. 7C. Indicates the target stroke speed with respect to the differential thrust when shifting to LFUS at a vehicle speed of 115 km / h.

With reference to FIGS. 5A to 5C, FIGS. 6A to 6C, and FIGS. 7A to 7C, it can be seen that the lower the vehicle speed VSP, the larger the slope of the target stroke speed with respect to the differential thrust when the shift scenes are the same.

Therefore, the map referred to by the control unit of the controller 12 may be changed according to the vehicle speed VSS.

In step S14, the control unit of the controller 12 sets the differential thrust according to the target stroke speed with reference to the map selected according to the shift scene, and changes the gear ratio of the variator 20.

As described above, the controller 12 of the present embodiment has a control unit that controls the shift of the variator 20 of the automatic transmission 1 with reference to a plurality of maps showing the relationship between the target stroke speed and the differential thrust. , A plurality of maps include a downshift map to be referred to when performing a downshift of the variator 20 and an upshift map to be referred to when performing an upshift of the variator 20, with respect to the differential thrust in the downshift map. The slope of the target stroke speed is larger than the slope of the target stroke speed with respect to the differential thrust in the upshift map. That is, the plurality of maps include at least two maps having different slopes of the target stroke speed with respect to the differential thrust.

According to this, the map to be referred to among the plurality of maps showing the relationship between the target stroke speed and the differential thrust is changed depending on whether the upshift is performed or the downshift is performed. Therefore, the differential thrust for obtaining the target stroke speed can be set accurately, and the target stroke speed is appropriately realized.

Further, the plurality of maps further include other downshift maps to be referred to when an input torque larger than the input torque to the variator 20 when referring to the downshift map is input to the variator 20, and the downshift is performed. The slope of the target stroke speed with respect to the differential thrust in the map is greater than the slope of the target stroke speed with respect to the differential thrust in other downshift maps.

According to this, the map referred to when downshifting is changed according to the input torque to the variator 20. Therefore, the differential thrust for obtaining the target stroke speed can be set more accurately, and the target stroke speed is appropriately realized.

Further, the plurality of maps further include other upshift maps to be referred to when an input torque larger than the input torque to the variator 20 when referring to the upshift map is input to the variator 20, and the upshift is made. The slope of the target stroke speed with respect to the differential thrust in the map is greater than the slope of the target stroke speed with respect to the differential thrust in other upshift maps.

According to this, the map referred to when performing the upshift is changed according to the input torque to the variator 20. Therefore, the differential thrust for obtaining the target stroke speed can be set more accurately, and the target stroke speed is appropriately realized.

Further, when the control unit of the controller 12 performs an upshift (LFUS shift) by releasing the foot from the accelerator pedal 41, the control unit refers to a map among a plurality of maps according to the elapsed time after the release from the accelerator pedal 41. To change.

According to this, the map referred to when performing the upshift is changed according to the elapsed time after the foot is released from the accelerator pedal 41. Therefore, the differential thrust for obtaining the target stroke speed can be set more accurately, and the target stroke speed is appropriately realized.

Although the embodiments of the present invention have been described above, the above-described embodiments are merely shown as one of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above-described embodiments. is not it.

For example, in the above embodiment, the controller 12 controls the engine 5, the automatic transmission 1, and the like in an integrated manner. However, the controller 12 can also be configured by a plurality of microcomputers. Further, for example, a controller as a control device for the automatic transmission 1 and a controller as a control device for the engine 5 may be provided, respectively.

Further, in view of the variation in the products, even in the same shift scene, a map corrected according to the variation for each automatic transmission 1 may be set by factory learning.

This application claims priority based on Japanese Patent Application No. 2019-91254 filed with the Japan Patent Office on May 14, 2019, and the entire contents of this application are incorporated herein by reference.

Claims (5)

A vehicle control device equipped with a belt continuously variable transmission.
The speed change control of the variator of the belt continuously variable transmission is the difference thrust that is the difference between the target stroke speed of the variator, the thrust acting on the primary pulley of the variator, and the thrust acting on the secondary pulley of the variator. It has a control unit that refers to multiple maps showing the relationship between
The plurality of maps include a downshift map to be referred to when performing a downshift of the variator, and an upshift map to be referred to when performing an upshift of the variator.
The slope of the target stroke speed with respect to the differential thrust in the downshift map is larger than the slope of the target stroke speed with respect to the differential thrust in the upshift map.
Vehicle control device. The vehicle control device according to claim 1.
The plurality of maps further include other downshift maps that are referenced when an input torque greater than the input torque to the variator when referring to the downshift map is input to the variator.
The slope of the target stroke speed with respect to the differential thrust in the downshift map is larger than the slope of the target stroke speed with respect to the differential thrust in the other downshift map.
Vehicle control device. The vehicle control device according to claim 1 or 2.
The plurality of maps further include other upshift maps to be referenced when an input torque larger than the input torque to the variator when referring to the upshift map is input to the variator.
The slope of the target stroke speed with respect to the differential thrust in the upshift map is larger than the slope of the target stroke speed with respect to the differential thrust in the other upshift maps.
Vehicle control device. The vehicle control device according to any one of claims 1 to 3.
When the control unit performs an upshift by releasing the foot from the accelerator pedal, the control unit changes the map to be referred to among the plurality of maps according to the elapsed time after the release from the accelerator pedal.
Vehicle control device. It is a control method for vehicles equipped with a belt continuously variable transmission.
The speed change control of the variator of the belt continuously variable transmission is the difference thrust that is the difference between the target stroke speed of the variator, the thrust acting on the primary pulley of the variator, and the thrust acting on the secondary pulley of the variator. Refer to multiple maps showing the relationship between
When performing the downshift of the variator, refer to the downshift map in which the slope of the target stroke speed with respect to the differential thrust is larger than the upshift map referred to when performing the upshift of the variator among the plurality of maps. do,
How to control the vehicle.

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