JP2020125788A - Control device for vehicle - Google Patents

Abstract

To suppress additional accelerator return operation or a sluggish feeling at the time of re-acceleration, when shifting down an automatic transmission during the return operation of an accelerator operation member to develop driving power source brake.SOLUTION: A control device for a vehicle can determine whether a slowdown achievement requiring time Td is short or not during the return operation of an accelerator pedal, and when determining that the slowdown achievement requiring time Td is short (Td≤T1), finish downshift in a short time in order to execute blipping control during the downshift. As a result, deceleration as intended is quickly obtained, the additional return operation of the accelerator pedal or braking operation for slowdown is lessened, and when the accelerator pedal is re-operated for acceleration right after the slowdown, quick acceleration is possible using a gear stage after the downshift, thus improving drivability for acceleration/deceleration.SELECTED DRAWING: Figure 5

Description

The present invention relates to a vehicle control device, and more particularly to a technique for obtaining a driving force source brake by downshifting an automatic transmission when an accelerator operation member is returned.

(a) An automatic transmission that shifts the rotation output from the driving force source and transmits the rotation to the drive wheels, and (b) an accelerator operating member that is operated by the driver according to the required output. (C) A vehicle control device having a drive force source brake control unit that downshifts the automatic transmission to obtain a drive force source brake when the accelerator operation member is returned by a driver. Are known. The device described in Patent Document 1 is an example of such a device, in which the deceleration intention is determined from the return operation speed of the accelerator operation member, the target deceleration is determined according to the deceleration intention, and downshifting is performed to a gear that obtains the target deceleration. It is supposed to do.

JP, 11-63211, A

However, even when the downshift is performed so that the target deceleration obtained according to the deceleration intention is obtained in this way, it takes time because the rotation speed of the driving force source needs to be increased by the downshift, which is sufficient. There is still room for improvement, such as additional accelerator release operation and brake operation being required before sufficient deceleration is obtained, and a feeling of rattling even if re-acceleration operation is performed before the end of the downshift.

The present invention has been made in view of the above circumstances, and an object thereof is to downshift an automatic transmission to obtain a driving force source brake when an accelerator operation member is returned. In this case, it is intended to suppress the rattling feeling at the time of additional accelerator return operation and reacceleration.

In order to achieve such an object, the present invention provides: (a) an automatic transmission that shifts the rotation output from a driving force source and transmits the rotation to driving wheels; and (b) an automatic transmission that is operated by a driver according to a required output. (C) a drive for providing a driving force source brake by downshifting the automatic transmission when the accelerator operation member is returned by a driver. In a control device for a vehicle having a power source brake control unit, (d) when the driving force source brake control unit performs a return operation of the accelerator operation member, the driver obtains based on an operation mode of the return operation. If it is determined that the deceleration achievement required time is short, and if it can be determined that the deceleration achievement required time is short, the blipping control for temporarily increasing the torque of the driving force source is executed when performing the downshift. It is characterized by doing.

In such a vehicle control device, when the accelerator operation member is returned, it is determined whether the deceleration achievement required time is short, and if it is determined that the deceleration achievement required time is short, the downshift is performed. Since the blipping control for temporarily increasing the torque of the driving force source is executed, the downshift can be completed in a short time. As a result, the target deceleration can be obtained quickly, and the returning operation and braking operation of the additional accelerator operating member for deceleration is reduced, and the accelerator operating member is re-operated immediately after deceleration. In the case of accelerating the vehicle, it is possible to accelerate quickly by the gear stage or gear ratio after the downshift, and the drivability for acceleration/deceleration is improved.

FIG. 1 is a schematic configuration diagram showing a skeleton diagram of a vehicle to which the present invention is preferably applied together with a main part of a control system. 3 is a flowchart for specifically explaining signal processing by a driving force source brake control unit of the vehicle of FIG. 1. It is a figure explaining an example of the map at the time of calculating the deceleration requirement Q in S1 of FIG. It is a figure explaining an example of the map at the time of calculating deceleration achievement required time Td in S6 of FIG. FIG. 3 is a diagram illustrating a shift type determined in S7 of FIG. 2. It is a figure explaining other Example of this invention, and is the figure which illustrated the area|region with a short deceleration achievement request time which performs downshift using blipping together.

The present invention is preferably applied to an engine-driven vehicle having an engine as a driving force source, but may also be applied to an electric vehicle having only a motor generator having an electric motor function as a driving force source. A driving force source brake can be obtained by regenerative control of the motor generator. The engine-driven vehicle may include an electric motor as a driving force source in addition to the engine. The engine is an internal combustion engine such as a gasoline engine or a diesel engine that generates power by burning fuel. The automatic transmission includes a stepped transmission such as a planetary gear type or a parallel shaft type having a plurality of gear stages having different gear ratios, a belt type capable of continuously changing the gear ratio, a toroidal type or the like. A gear transmission can be used. An electric continuously variable transmission that continuously changes the rotation of the driving force source and outputs it to the driving wheels by regenerative control of a motor generator connected to the driving force source via a differential mechanism such as a planetary gear device. It can also be adopted.

The operation mode of the return operation for determining whether or not the deceleration achievement request time is short is, for example, the return operation speed of the accelerator operation member, the operation amount after the return operation (remaining operation amount), the change amount at the time of the return operation, or the like. It is desirable to make the determination based on at least the return operation speed. When the return operation speed is fast, it can be determined that the deceleration achievement required time is short. When making a determination based on the remaining operation amount, it can be determined that the deceleration achievement request time is short when the remaining operation amount is small. When making the determination based on the amount of change at the time of the return operation, it can be determined that the deceleration achievement required time is short when the amount of change is large. The determination may be made based on any one of the operation modes, but it may be determined comprehensively from a plurality of operation modes. Further, not only the operation mode of the accelerator operation member but also the operation mode other than the accelerator operation member such as the presence or absence of the brake operation and the brake operation amount (force) can be considered to determine whether the deceleration achievement request time is short. it can.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram in which a skeleton diagram of a vehicle 10 to which the present invention is applied and a main part of a control system are shown together. The vehicle 10 is an engine-driven vehicle having an engine 12 as a driving force source, and the output of the engine 12 is transmitted from the automatic transmission 14 to the left and right drive wheels 18 via the differential gear device 16. Although a power transmission device such as a damper device or a torque converter is provided between the engine 12 and the automatic transmission 14, a motor generator that functions as a driving force source may be provided.

The engine 12 includes various engine control devices 30 such as an electronic throttle valve and a fuel injection device necessary for output control of the engine 12. The electronic throttle valve controls the intake air amount, and the fuel injection device controls the fuel supply amount. The automatic transmission 14 is a stepped automatic gear shift system such as a planetary gear system that can establish a plurality of forward gear stages having different gear ratios depending on the engagement/disengagement states of a plurality of hydraulic friction engagement devices (clutch and brake). In the machine, shift control is performed by switching engagement/disengagement states of a plurality of hydraulic friction engagement devices by an electromagnetic hydraulic control valve or a switching valve provided in the hydraulic control device 32. As the automatic transmission 14, a continuously variable transmission such as a belt type may be used instead of the stepped transmission.

The vehicle 10 is electronically controlled as a controller for controlling the output of the engine 12 via the engine control device 30 and performing shift control for switching the forward gear of the automatic transmission 14 via the hydraulic control device 32. A device 40 is provided. The electronic control unit 40 is configured to include a so-called microcomputer having a CPU, a ROM, a RAM, an input/output interface, and the like, and performs signal processing according to a program stored in advance in the ROM while using the temporary storage function of the RAM. To do. The electronic control unit 40 is supplied with a signal representing the accelerator operation amount θacc, which is the depression operation amount of the accelerator pedal 52, from the accelerator operation amount sensor 50, and is the depression operation amount of the brake pedal 56 from the brake operation amount sensor 54. A signal representing the brake operating force Brk is supplied. The accelerator operation amount θacc corresponds to the required output, and the accelerator pedal 52 is an accelerator operating member operated by the driver according to the required output. The brake pedal 56 is a brake operating member operated by the driver according to the required braking force.

The electronic control unit 40 also uses the engine rotation speed sensor 58, the input rotation speed sensor 60, the output rotation speed sensor 62, the vehicle weight sensor 64, and the road surface gradient sensor 66 to determine the rotation speed of the engine 12 (engine rotation speed) Ne, Signals representing the input rotation speed Nin of the transmission 14, the output rotation speed Nout of the automatic transmission 14, the vehicle weight X, and the road surface gradient Φ are supplied. The output rotation speed Nout corresponds to the vehicle speed V. The vehicle weight sensor 64 may estimate the vehicle weight X by detecting the number of passengers in the vehicle, for example, based on the state of use of the seat belt. The vehicle weight X and the road surface slope Φ can also be calculated from the engine torque Te and the vehicle acceleration. Further, the friction coefficient μ of the road surface can be received by using an information receiving device (not shown) or the like, so that various kinds of information necessary for various controls are supplied.

The electronic control unit 40 functionally includes an engine control unit 42, a shift control unit 44, and a driving force source brake control unit 46. The engine control unit 42 basically controls the electronic throttle valve and the fuel injection device of the engine control device 30 so as to increase or decrease the output of the engine 12 according to the accelerator operation amount θacc. Further, even when the vehicle is traveling, a fuel cut (hereinafter also referred to as F/C) is performed to stop the fuel supply by the fuel injection device when the accelerator operation amount θacc is 0 and the accelerator is off. The shift control unit 44 basically controls the hydraulic control device 32 to switch the forward gear of the automatic transmission 14 according to a predetermined shift condition. The speed change condition is, for example, a speed change map in which the vehicle speed V and the accelerator operation amount θacc are set as a parameter. The higher the vehicle speed V is, the higher the gear ratio is, and the higher the accelerator operation amount θacc is. It is determined that the gear can be switched to a low gear having a large ratio.

When the accelerator pedal 52 is operated to return, the driving force source brake control unit 46 downshifts the automatic transmission 14 to increase the engine rotation speed Ne as necessary, and controls the pumping loss of the engine 12 or the like. Power (driving force source brake) is applied, and signal processing is executed in accordance with steps S1 to S10 (hereinafter simply referred to as S1 to S10) in the flowchart of FIG. The electronic control unit 40 is a control unit that functionally includes the driving force source brake control unit 46.

The flowchart of FIG. 2 is executed when the accelerator pedal 52 is returned while the vehicle is traveling, and in S1, it corresponds to the magnitude of the driver's intention to decelerate based on the operation mode of the return operation of the accelerator pedal 52. The deceleration demand degree Q to be calculated is calculated. FIG. 3 is an example of the deceleration demand map for calculating the deceleration demand Q, in which the return operation speed γ of the accelerator pedal 52 and the remaining operation amount rθ that is the accelerator operation amount θacc after the return operation are set as parameters. Therefore, the higher the return operation speed γ and the smaller the remaining operation amount rθ, the larger the deceleration requirement Q becomes. The deceleration requirement Q may be obtained in consideration of the return amount Δθ which is the change amount of the accelerator operation amount θacc during the return operation, the presence or absence of the brake operation, and the like. Further, the deceleration requesting degree Q may be calculated according to an arithmetic expression defined by using those physical quantities as parameters.

In the next step S2, it is determined whether or not the deceleration/next acceleration request is made depending on whether or not the deceleration request degree Q is equal to or more than the deceleration request determination value Qs. The deceleration request determination value Qs may be set to a fixed value in advance, but is not limited to external factors such as the vehicle weight X and the road surface slope Φ, and hardware protection such as a shock due to a downshift and excessive rotation of the engine rotation speed Ne. The deceleration request determination value Qs may be corrected or limited based on a physical factor. For example, when the vehicle weight X is large or the road surface slope Φ is large on the descending side, the vehicle 10 is difficult to decelerate, so the deceleration request determination value Qs is made small and the driving force source brake control with downshift is easily executed. To do. Then, when the deceleration request rate Q is equal to or higher than the deceleration request determination value Qs, it is determined that there is deceleration intention and S3 and below are executed. When the deceleration request rate Q is smaller than the deceleration request determination value Qs, the special deceleration intention is set. It judges that there is no, and ends as it is.

In step S3, the vehicle deceleration obtained by the driving force source brake based on the current gear is calculated as the input torque of the automatic transmission 14, the rotational load (such as drag) of the transmission path from the engine 12 to the drive wheels 18, and the friction coefficient of the road surface. μ, the road surface gradient Φ, etc. are calculated, the difference from the required deceleration (target deceleration) obtained from the deceleration demand Q, etc. is converted into a gear ratio, and the target gear that obtains the required deceleration. Set the steps. In S4, the current gear stage and the target gear stage are compared to determine whether or not a downshift is necessary. If a downshift is required, S5 and the subsequent steps are executed. If no downshift is required, the process ends.

In S5, it is determined whether or not the downshift to the target gear can be performed based on the viewpoint of hardware protection and the driver's intention to decelerate. For example, when the engine speed Ne after the downshift and the amount of change thereof are equal to or more than a predetermined value, the downshift to the target gear is stopped or the target gear is limited. The downshift to the target gear stage may be stopped or the target gear stage may be limited based on the rotation speed of each part of the automatic transmission 14 other than the engine rotation speed Ne. Also, when the driver depresses the accelerator pedal 52, it is determined that the intention of deceleration has been resolved and the downshift to the target gear is stopped. When the downshift is stopped in S5, the processing is ended as it is, and when the downshift to the target gear stage or the limited target gear stage is executed, S6 and subsequent steps are executed.

In S6, the deceleration achievement request time Td required by the driver is calculated based on the operation mode of the returning operation of the accelerator pedal 52. FIG. 4 is an example of a deceleration achievement required time map for calculating the deceleration achievement required time Td, in which the return operation speed γ of the accelerator pedal 52 and the remaining operation amount rθ which is the accelerator operation amount θacc after the return operation are set as parameters. As the return operation speed γ is faster and the remaining operation amount rθ is smaller, the deceleration achievement required time Td becomes shorter. Compared to the deceleration requirement map of FIG. 3, the return operation speed γ has a greater dependency. The deceleration achievement required time Td may be obtained in consideration of the return amount Δθ which is the change amount of the accelerator operation amount θacc during the return operation, the presence or absence of the brake operation, and the like. Further, the deceleration achievement required time Td may be calculated according to an arithmetic expression defined by using those physical quantities as parameters.

In the next step S7, the type of shift when downshifting to the target gear is determined based on the deceleration achievement request time Td. In the present embodiment, as shown in FIG. 5, three types of speed change are defined, that is, a first downshift control, a second downshift control, and a third downshift control. The first downshift control is a control for returning to fuel injection at the time of F/C (fuel cut) and performing a downshift by performing a blipping control for temporarily increasing the engine torque. It is necessary after the downshift is completed. Accordingly, the F/C is restarted. By performing the blipping control, the engine rotation speed Ne is quickly increased, so that the downshift can be completed in a short time. The second downshift control is a control for returning to fuel injection at the time of F/C, executing the downshift with the engine 12 in an idling state, and restarting the F/C as necessary after the end of the downshift. When the engine 12 is in the idling state, the engine rotation speed Ne is easily increased, and the downshift time is shortened as compared with the case where the downshift is performed with F/C. The third downshift control is a control for executing the downshift as it is at the time of F/C. Since a negative torque is generated in the engine 12 at the time of F/C, the downshift time becomes long.

Then, if the deceleration achievement required time Td is equal to or less than the predetermined first determination value T1, it is determined that the driver desires rapid deceleration, and the first downshift control is selected. When the deceleration achievement required time Td is longer than the first determination value T1, it is determined whether or not it is shorter than the second determination value T2 (>T1). If T1<Td<T2, the second downshift control is performed. select. If the deceleration achievement required time Td is equal to or greater than the second determination value T2, the driver determines that the sudden deceleration is not required and selects the third downshift control. The first determination value T1 and the second determination value T2 may each be set to a fixed value in advance, but may be corrected depending on the running state of the vehicle such as the vehicle weight X and the road surface gradient Φ. It is also possible to limit the types of shift that can be selected based on the running state of the vehicle. If T2≦Td and F/C is not executed, it is not necessary to intentionally execute F/C, and the second downshift control without F/C may be selected. Further, when T1<Td, the downshift is executed as F/C at the time of F/C without distinguishing between the second downshift control and the third downshift control, and if it is not F/C, the engine 12 The downshift may be executed in the idling state. Further, when T1<Td, the engine 12 may be kept idling and the downshift may be executed.

In S8, downshift control is executed in accordance with the shift type selected in S7. That is, the gear shift control unit 44 gives priority to the normal gear shift control, downshifts to the target gear stage, and the engine control unit 42 gives priority to the normal engine control, and the F/C is stopped to idle. The state and the blipping control are performed. As a result, in the second downshift control and the third downshift control, the driving force source brake can be obtained even during the downshift control, and the target required deceleration can be obtained after the downshift is completed. In the case of the first downshift control, the downshift is ended in a short time by the blipping control of the engine 12, and the blipping control is ended to restart the engine 12 in the idling state or F/C. , The target required deceleration can be obtained by the driving force source brake.

In S9, it is determined whether or not the condition for returning to the normal shift control by the shift control unit 44 is satisfied. If the condition for returning is satisfied, the process returns to the normal shift control in S10. The return condition is determined based on, for example, the driver's intention of acceleration/deceleration or the viewpoint of hardware protection. For example, when the driver's intention to decelerate or intention to re-accelerate after deceleration is resolved, the return condition is satisfied and the normal shift control is resumed. These intentions of acceleration/deceleration can be determined from the operating states of the accelerator pedal 52 and the brake pedal 56, the vehicle speed V, and the like. When the engine rotation speed Ne and the rotation speed of each part such as the automatic transmission 14 are equal to or higher than a predetermined value, normal gear shift control is resumed from the viewpoint of hardware protection.

As described above, in the electronic control unit 40 of the vehicle 10 of the present embodiment, it is determined whether or not the deceleration achievement required time Td is short when the accelerator pedal 52 is operated to return, and if the deceleration achievement required time Td is short. If it can be determined (Td≦T1), the blipping control is executed when the downshift is performed, so that the downshift can be completed in a short time. As a result, the target deceleration can be quickly obtained, and additional return operation and braking operation of the accelerator pedal 52 for deceleration are reduced, and the accelerator pedal 52 is re-operated immediately after deceleration. In the case of accelerating the vehicle, it is possible to accelerate quickly by the gear after the downshift, and the drivability for acceleration/deceleration is improved.

In the above-described embodiment, the deceleration achievement required time Td is calculated and the blipping control is performed when the deceleration achievement required time Td is equal to or less than the predetermined first determination value T1. However, the deceleration achievement required time Td is not necessarily calculated. Alternatively, whether or not the deceleration achievement request time is short, that is, whether or not the blipping control is performed may be directly determined from the operation mode when the accelerator pedal 52 is returned. For example, FIG. 6 shows a case where the judgment is made based on the return operation speed γ and the remaining operation amount rθ as in the case of the above embodiment, and when the return operation speed γ is equal to or more than a predetermined value and the remaining operation amount rθ is less than or equal to the predetermined value. , And determines that the deceleration achievement request time required by the driver is short and executes the blipping control.

The embodiments of the present invention have been described above in detail with reference to the drawings. However, these are merely embodiments, and the present invention is implemented in various modifications and improvements based on the knowledge of those skilled in the art. be able to.

10: Vehicle 12: Engine (driving force source) 14: Automatic transmission 18: Driving wheel 40: Electronic control device (control device) 46: Driving force source brake control unit 52: Accelerator pedal (accelerator operating member) Td: Achieve deceleration Request time

Claims (1)

An automatic transmission that shifts the rotation output from the driving force source and transmits it to the driving wheels,
An accelerator operating member that is operated by the driver according to the required output,
A vehicle having a driving force source brake control unit that downshifts the automatic transmission to obtain a driving force source brake when the accelerator operation member is returned by a driver. In the control device,
When the accelerator operation member is returned, the driving force source brake controller determines whether the deceleration achievement request time required by the driver is short based on the operation mode of the returning operation, and the deceleration is achieved. When it is determined that the required time is short, a blipping control for temporarily increasing the torque of the driving force source is executed when the downshift is performed.

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