JP2020197187A - Vehicle control device and vehicle control method - Google Patents

Abstract

To provide a vehicle control device that can immediately reach a target vehicle speed at automatic operation in a vehicle with a continuously variable transmission, and to provide a vehicle control method.SOLUTION: A controller 10 determines a basic output torque Tb of an engine 1, sets a total torque in which a correction output torque Ta is added to the basic output torque Tb at automatic operation as a target output torque Tt of the engine 1, and changes the correction output torque Ta in accordance with a state of an automatic transmission 3.SELECTED DRAWING: Figure 2

Description

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

Patent Document 1 discloses a vehicle control device that determines an engine torque correction amount so that a vehicle speed reaches a target vehicle speed based on the characteristics of a torque converter.

Japanese Unexamined Patent Publication No. 2-133242

In automatic vehicle driving (including constant-speed driving), in a scene where the target vehicle speed (target vehicle speed) changes due to a large increase in the distance from the vehicle in front, the vehicle speed should be quickly reached to the target vehicle speed. Is required.

The continuously variable transmission has a loss during power transmission, and even if the output torque of the torque converter is corrected as in the vehicle control device described in Patent Document 1, the output torque actually transmitted to the drive wheels is continuously variable transmission. It varies depending on the condition of the machine.

Therefore, depending on the state of the continuously variable transmission, the loss during power transmission becomes large. For this reason, sufficient acceleration may not be obtained, and it may take time for the vehicle speed to reach the target vehicle speed.

The present invention has been made in view of such technical problems, and provides a vehicle control device and a vehicle control method capable of quickly reaching a target vehicle speed during automatic driving in a vehicle having a continuously variable transmission. The purpose.

According to an aspect of the present invention, a vehicle control device that controls a vehicle having a drive source and a continuously variable transmission has a control unit that determines a basic output torque of the drive source, and the control unit is a control unit. The feature is that the total torque obtained by adding the correction output torque to the basic output torque during automatic operation is set as the target output torque of the drive source, and the control unit changes the correction output torque according to the state of the continuously variable transmission. ..

According to another aspect of the present invention, a vehicle control method for controlling a vehicle having a drive source and a continuously variable transmission determines the basic output torque of the drive source and determines the basic output torque during automatic operation. It is characterized in that the total torque including the correction output torque is set as the target output torque of the drive source, and the correction output torque is changed according to the state of the continuously variable transmission.

In these aspects, the target vehicle speed can be quickly reached by changing the corrected output torque according to the state of the continuously variable transmission.

It is a schematic block diagram of the vehicle which concerns on embodiment of this invention. It is a flowchart which shows the flow of control which concerns on embodiment of this invention. It is a map for obtaining the 1st correction output torque which concerns on embodiment of this invention. It is a map for obtaining the 2nd correction output torque which concerns on embodiment of this invention.

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

FIG. 1 is a schematic configuration diagram of the vehicle 100. The vehicle 100 includes an engine 1, an automatic transmission 3 as a continuously variable transmission, an oil pump 5, a drive wheel 6, and a controller 10 as a control device.

The engine 1 is an internal combustion engine that uses gasoline, light oil, or the like as fuel, and functions as a driving source for traveling. The engine 1 is controlled in rotation speed, torque, and the like based on a command from the controller 10.

The automatic transmission 3 includes a torque converter 2, a fastening element 31, a variator 30, a hydraulic control valve unit 40 (hereinafter, also simply referred to as “valve unit 40”), and oil for storing oil (hydraulic oil). The pan 32 and the like are provided.

The torque converter 2 is provided on the power transmission path between the engine 1 and the drive wheels 6. The torque converter 2 transmits power via a fluid. Further, the torque converter 2 can improve the power transmission efficiency of the driving force from the engine 1 by engaging the lockup clutch 2a.

The fastening element 31 is arranged on the power transmission path between the torque converter 2 and the variator 30. The fastening element 31 includes a forward clutch and a reverse brake (not shown). The fastening element 31 is controlled by the oil adjusted by the valve unit 40 with the discharge pressure of the oil pump 5 as the original pressure based on the command from the controller 10. As the fastening element 31, for example, a multi-plate clutch is used.

The variator 30 is arranged on the power transmission path between the fastening element 31 and the drive wheels 6, and changes the gear ratio steplessly according to the vehicle speed, the accelerator opening degree, and the like. The variator 30 includes a primary pulley 30a, a secondary pulley 30b, and a belt 30c wound around both pulleys 30a and 30b. The gear ratio is steplessly changed by moving the movable pulley of the primary pulley 30a and the movable pulley of the secondary pulley 30b in the axial direction by the pulley pressure and changing the pulley contact radius of the belt 30c. The pulley pressure acting on the primary pulley 30a and the pulley pressure acting on the secondary pulley 30b are adjusted by the valve unit 40 with the discharge pressure from the oil pump 5 as the original pressure.

A differential 12 is connected to the output shaft of the secondary pulley 30b of the variator 30 via a final reduction gear mechanism (not shown). The drive wheels 6 are connected to the differential 12 via the drive shaft 13.

The oil pump 5 is driven by transmitting the rotation of the engine 1 via a belt. The oil pump 5 is composed of, for example, a vane pump. The oil pump 5 sucks up the oil stored in the oil pan 32 and supplies the oil to the valve unit 40. The oil supplied to the valve unit 40 is used for driving the lockup clutch 2a, driving the pulleys 30a and 30b, driving the fastening element 31, and lubricating each element of the automatic transmission 3.

The controller 10 is composed of a microcomputer including a central arithmetic unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 10 may be composed of a plurality of microcomputers. Specifically, the controller 10 is composed of an ATCU that controls the automatic transmission 3, an SCU that controls the shift range, an ECU that controls the engine 1, and the like. The control unit for calculating the target output torque Tt and the like, which will be described later, is a virtual unit having the function of the controller 10 for calculating the target output torque Tt and the like.

The controller 10 includes a first rotation speed sensor 51 that detects the rotation speed Ne of the engine 1, a second rotation speed sensor 52 that detects the rotation speed of the turbine (turbine rotation speed Ntout) on the output shaft side of the torque converter 2. A third rotation speed sensor 53 that detects the output rotation speed Nout (rotation speed of the primary pulley 30a) of the fastening element 31, a fourth rotation speed sensor 54 that detects the rotation speed of the secondary pulley 30b, and a vehicle speed sensor 55 that detects the vehicle speed V. , Inhibita switch 56 that detects the select range of the fastening element 31 (the state of the select lever or select switch that switches between forward, reverse, neutral and parking), accelerator opening sensor 57 that detects the accelerator opening AP, and detects the pedal effort of the brake. Signals from the tread force sensor 58, the torque sensor 59 that detects the output torque of the engine 1, and the like are input. The controller 10 controls various operations of the engine 1 and the automatic transmission 3 based on these input signals.

In the vehicle 100 of the present embodiment, it is possible to select automatic driving in which the controller 10 automatically controls the control of the vehicle speed V. In the automatic operation of the present embodiment, for example, when accelerating the vehicle speed V to the target vehicle speed (target vehicle speed Vt), the controller 10 first calculates the target acceleration (target acceleration αt), and further. The output torque (basic output torque Tb) of the engine 1 for realizing this target acceleration αt is calculated. Then, the controller 10 controls the engine 1 so as to output the basic output torque Tb.

By the way, when power is transmitted from the engine 1 to the drive wheels 6, a loss occurs in the automatic transmission 3. When such a loss occurs, the torque actually transmitted to the drive wheels 6 becomes smaller than the basic output torque Tb. As a result, the actual acceleration becomes smaller than the target acceleration αt, so that it takes time for the vehicle speed V to reach the target vehicle speed Vt, and the acceleration feeling deteriorates.

Therefore, in the present embodiment, control is performed with the total torque obtained by adding the corrected output torque Ta in consideration of the loss of the automatic transmission 3 to the basic output torque Tb during automatic operation as the target output torque Tt of the engine 1.

Hereinafter, a method for calculating the target output torque Tt will be specifically described with reference to FIGS. 2 to 4. The control described below is executed by a program stored in advance in the controller 10 during automatic operation. The automatic driving in the following description includes driving support such as fully automatic driving, highly automatic driving, constant speed driving control, and control for keeping the distance between vehicles constant. In other words, the control described below can be applied to anything as long as the vehicle speed V is automatically controlled by the controller 10.

First, in step S1, the basic output torque Tb is calculated. Specifically, the controller 10 calculates the target acceleration αt based on the target vehicle speed Vt with reference to a map (not shown), and calculates the basic output torque Tb which is the output torque of the engine 1 for realizing the target acceleration αt. Ask. The basic output torque Tb is set to a larger value as the target acceleration αt is higher. The basic output torque Tb is set higher as the rotation speed of the engine 1 is higher.

In step S2, the correction output torque Ta is calculated. The corrected output torque Ta is set to a value corresponding to the amount of torque loss that occurs in the automatic transmission 3 until the torque output from the engine 1 is transmitted to the drive wheels 6. Here, the torque loss that occurs in the automatic transmission 3 will be described.

The torque loss generated in the automatic transmission 3 is roughly divided into a loss caused by each mechanism of the automatic transmission 3 and a loss caused by the hydraulic oil in the automatic transmission 3. The loss caused by each mechanism of the automatic transmission 3 includes a loss in the oil pump 5 and a loss in the variator 30.

As the torque from the engine 1 input to the automatic transmission 3 is larger, the line pressure is increased in order to suppress the slip of the belt 30c, and the pulley pressures of the primary pulley 30a and the secondary pulley 30b are further increased to prevent the primary pulley 30a. And it is necessary to increase the clamping force of the secondary pulley 30b. When the line pressure and the clamping force increase, the friction between the parts of the variator 30 increases, and the loss due to the friction increases accordingly.

Further, in the oil pump 5, since the discharge pressure is increased in order to increase the line pressure, the loss due to friction and heat generation is increased accordingly.

Therefore, in the present embodiment, the larger the engine torque input to the automatic transmission 3, that is, the target engine torque, the larger the correction amount of the basic output torque Tb (first correction output torque Ta1) is set (1st correction output torque Ta1). (See FIG. 3).

Further, when the rotation speed of the engine 1 is high, the loss tends to be larger than when the rotation speed of the engine 1 is low. Therefore, also in this case, the correction amount of the basic output torque Tb (first correction output torque Ta1). ) Is set large (see Fig. 3). The rotation speed of the engine 1 is proportional to the rotation speed of the input shaft of the automatic transmission 3.

FIG. 3 shows the first corrected output torque Ta1 in which the rotation speed is set every 1000 rotations, but in reality, the first corrected output torque Ta1 is set at finer rotation speed intervals. Of course, the first correction output torque Ta1 may be continuously changed according to the change in the rotation speed.

The viscosity of hydraulic oil changes depending on the oil temperature. When the oil temperature is low, the viscosity becomes high. The higher the viscosity, the greater the amount of torque loss. On the contrary, when the oil temperature is high, the viscosity becomes low. The higher the viscosity, the greater the amount of torque loss. Therefore, in the present embodiment, the lower the oil temperature, the larger the torque correction amount (second correction output torque Ta2) is set (see FIG. 4).

In the present embodiment, the controller 10 compensates for the first corrected output torque Ta1 that compensates for the loss caused by each mechanism of the automatic transmission 3 set as described above, and the loss caused by the change in the oil temperature. The sum of the second corrected output torque Ta2 and the corrected output torque Ta2 is calculated as the corrected output torque Ta2.

In step S3, the target output torque Tt is calculated. Specifically, the controller 10 calculates the total torque as the target output torque Tt by adding the correction output torque Ta calculated in step S2 to the basic output torque Tb calculated in step S1.

The controller 10 controls the output torque of the engine 1 based on the target output torque Tt calculated in this way.

As described above, in the present embodiment, the corrected output torque Ta is changed according to the state of the automatic transmission 3 (input engine torque (basic output torque Tb), rotation speed, oil temperature), specifically. Is set to a larger correction output torque Ta as the loss in the automatic transmission 3 increases, so that the target vehicle speed Vt can be reached more quickly.

Further, in the present embodiment, all of the torque input to the automatic transmission 3, the rotation speed of the automatic transmission 3, and the oil temperature of the automatic transmission 3 are taken into consideration, so that the required acceleration can be obtained with high accuracy. At the same time, unnecessary energy consumption can be suppressed. Further, since the target output torque Tt is set to a value corresponding to the torque loss in the automatic transmission 3, the output torque of the engine 1 is not excessively increased. As a result, sudden acceleration (feeling of popping out) can be suppressed.

The configuration, operation, and effect of the embodiment of the present invention configured as described above will be collectively described.

The control device (controller 10) controls a vehicle 100 having a drive source (engine 1) and a continuously variable transmission (automatic transmission 3). The controller 10 has a control unit (controller 10) that determines the basic output torque Tb of the drive source (engine 1), and the control unit (controller 10) adds a correction output torque Ta to the basic output torque Tb during automatic operation. The total torque is set to the target output torque Tt of the drive source (engine 1), and the correction output torque Ta is changed according to the state of the continuously variable transmission (automatic transmission 3).

Since the magnitude of torque loss changes depending on the state of the continuously variable transmission (automatic transmission 3), the target is to change the correction output torque Ta according to the state of the continuously variable transmission (automatic transmission 3). It can be reached quickly by the vehicle speed Vt. As a result, deterioration of the acceleration feeling can be suppressed (effects of the inventions of claims 1 and 5).

The control unit (controller 10) sets the correction output torque Ta (first correction output torque Ta1) larger as the target acceleration αt during automatic operation is higher.

Since the loss of the continuously variable transmission (automatic transmission 3) tends to increase as the target acceleration αt increases, the correction output torque Ta (first correction output torque Ta1) should be set larger as the target acceleration αt increases. Therefore, the target vehicle speed Vt can be reached quickly (effect of the invention of claim 2).

Further, the lower the target acceleration αt, the smaller the basic output torque Tb is set, and the smaller the basic output torque Tb, the smaller the correction output torque Ta (first correction output torque Ta1). Therefore, when the target acceleration αt is low, the degree of increase in the corrected output torque Ta (first corrected output torque Ta1) becomes small, so that deterioration of fuel efficiency can be suppressed (the effect of the invention of claim 2). ).

It is conceivable to always add a constant correction output torque Ta regardless of the target acceleration αt, but if this is done, the target output torque Tt may become excessive and the vehicle 100 may suddenly accelerate. Therefore, as in the present embodiment, the higher the target acceleration αt, the larger the correction output torque Ta can be set, so that more appropriate control can be performed.

The control unit (controller 10) sets the correction output torque Ta (first correction output torque Ta1) larger as the rotation speed of the drive source (engine 1) during automatic operation increases.

Since the loss of the continuously variable transmission (automatic transmission 3) tends to increase as the rotation speed of the drive source (engine 1) increases, the correction output torque Ta (corrected output torque Ta) increases as the rotation speed of the drive source (engine 1) increases. By setting the first corrected output torque Ta1) to a large value, the target vehicle speed Vt can be reached more quickly (effect of the invention of claim 3).

The lower the rotation speed of the drive source (engine 1), the smaller the basic output torque Tb is set, and the smaller the basic output torque Tb, the smaller the correction output torque Ta (first correction output torque Ta1). Therefore, when the rotation speed of the drive source (engine 1) is low, the degree of increase in the correction output torque Ta (first correction output torque Ta1) is small, so that deterioration of fuel efficiency can be suppressed (claimed). Effect of the invention of item 3).

The control unit (controller 10) sets the correction output torque Ta (second correction output torque Ta2) larger as the oil temperature of the continuously variable transmission (automatic transmission 3) during automatic operation is lower.

The lower the oil temperature of the continuously variable transmission (automatic transmission 3), the larger the loss of the continuously variable transmission (automatic transmission 3) tends to be. Therefore, the oil temperature of the continuously variable transmission (automatic transmission 3) tends to increase. The lower the value, the faster the target vehicle speed Vt can be reached by setting the corrected output torque Ta (second corrected output torque Ta2) (effect of the invention of claim 4).

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the purpose of limiting the technical scope of the present invention to the specific configurations of the above embodiments. is not.

In the above embodiment, the engine 1 has been described as an example of the drive source, but the drive source may be a motor. Further, it may be applied to a hybrid vehicle in which an engine and a motor are used together as a drive source.

The gear ratio of the automatic transmission 3 may be added to the corrected output torque Ta. Specifically, for example, if the gear ratio is on the Low side, the corrected output torque Ta may be made larger than that on the High side.

1 Engine 2 Torque converter 3 Automatic transmission (continuously variable transmission)
5 Oil pump 10 Controller (control device, control unit)
30 Variator 100 Vehicles

Claims (5)

In a vehicle control device that controls a vehicle having a drive source and a continuously variable transmission.
It has a control unit that determines the basic output torque of the drive source.
The control unit sets the total torque obtained by adding the correction output torque to the basic output torque to the target output torque of the drive source during automatic operation.
The control unit is a vehicle control device, characterized in that the corrected output torque is changed according to the state of the continuously variable transmission. In the vehicle control device according to claim 1.
The control unit is a vehicle control device, characterized in that the correction output torque is set larger as the target acceleration during automatic driving is higher. In the vehicle control device according to claim 1 or 2.
The control unit is a vehicle control device, characterized in that the correction output torque is set larger as the rotation speed of the drive source during the automatic driving is higher. In the vehicle control device according to any one of claims 1 to 3.
The control unit is a vehicle control device, characterized in that the correction output torque is set larger as the oil temperature of the continuously variable transmission during the automatic operation is lower. In a vehicle control method for controlling a vehicle having a drive source and a continuously variable transmission,
Determine the basic output torque of the drive source
During automatic operation, the total torque obtained by adding the correction output torque to the basic output torque is set as the target output torque of the drive source.
A vehicle control method, characterized in that the corrected output torque is changed according to the state of the continuously variable transmission.

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