JP7135906B2 - vehicle controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle, and more particularly to a technique for downshifting an automatic transmission to obtain driving force source braking when an accelerator operating member is operated to return.

A vehicle equipped with (a) an automatic transmission that shifts rotation output from a driving force source and transmits it to drive wheels, and (b) an accelerator operation member that is operated by a driver according to the required output. and (c) a control device for a vehicle having a driving force source brake control section for downshifting the automatic transmission to obtain driving force source braking when the accelerator operating member is operated to return by the driver. Are known. The device described in Patent Document 1 is an example of such a device. It determines the deceleration intention from the return operation speed of the accelerator operation member, determines the target deceleration according to the deceleration intention, and downshifts to the gear stage where the target deceleration is obtained. It is designed to

JP-A-11-63211

However, even when downshifting is performed so as to obtain the target deceleration determined in accordance with the intention of deceleration, it is necessary to increase the rotational speed of the driving force source during the downshift, which takes time and is sufficient. There is still room for improvement, such as the need for an additional accelerator release operation or brake operation before a sufficient deceleration is obtained, and the feeling of sluggishness when re-accelerating before the end of the downshift.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to downshift an automatic transmission to obtain driving force source braking when an accelerator operating member is operated to return. To suppress an additional accelerator return operation and a sluggish feeling at the time of re-acceleration when a

In order to achieve these objects, the present invention provides (a) an automatic transmission that changes the speed of rotation output from a driving force source and transmits it to drive wheels, and (b) an automatic transmission that is operated by a driver according to the required output. and (c) a drive that downshifts the automatic transmission to obtain driving force source braking when the accelerator operation member is operated to return by the driver. In a vehicle control device having a power source brake control unit, (d) the driving force source brake control unit is controlled by a driver based on the operation mode of the return operation when the accelerator operation member is operated to return. It is determined whether or not the required time to achieve deceleration is short, and if it is determined that the required time to achieve deceleration is short, blipping control is executed to temporarily increase the torque of the driving force source when performing the downshift. On the other hand, when it cannot be determined that the deceleration achievement request time is short, the downshift is executed without performing the blipping control .

In such a vehicle control device, when the accelerator operation member is operated to return, it is determined whether or not the deceleration achievement request time is short. Since blipping control is executed to temporarily increase the torque of the driving force source, the downshift can be completed in a short period of time. As a result, the desired deceleration can be obtained quickly, the additional operation of returning the accelerator operation member for deceleration, the brake operation, etc., can be reduced, and the accelerator operation member can be operated again immediately after deceleration. When the vehicle is accelerated, the gear stage or gear ratio after downshifting enables rapid acceleration, improving drivability with respect to acceleration and deceleration.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing a main part of a control system together with a skeleton diagram of a vehicle to which the present invention is preferably applied; 2 is a flowchart specifically explaining signal processing by a driving force source brake control unit of the vehicle in FIG. 1; FIG. 3 is a diagram illustrating an example of a map used when calculating a deceleration request degree Q in S1 of FIG. 2; FIG. FIG. 3 is a diagram illustrating an example of a map used when calculating a deceleration achievement required time Td in S6 of FIG. 2; FIG. FIG. 3 is a diagram for explaining a shift type determined in S7 of FIG. 2; FIG. FIG. 11 is a diagram for explaining another embodiment of the present invention, and is a diagram exemplifying a region with a short required deceleration achievement time required for downshifting using blipping.

INDUSTRIAL APPLICABILITY The present invention is preferably applied to an engine-driven vehicle having an engine as a driving force source, but can 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. Automatic transmissions include stepped transmissions such as planetary gear types and parallel shaft types that have multiple gear stages with different gear ratios, and belt-type and toroidal types that can continuously change the gear ratio. A stepped transmission can be used. An electric continuously variable transmission that continuously changes the rotation of the driving force source through regenerative control of a motor generator connected to the driving force source via a differential mechanism such as a planetary gear device and outputs the output to the drive wheels. 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 amount of change during the return operation, etc. It is desirable to make a determination based on at least the return operation speed. If the return operation speed is high, it can be determined that the deceleration achievement request time is short. When the determination is made 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 the determination is made based on the amount of change during the return operation, it can be determined that the requested deceleration achievement time is short when the amount of change is large. The determination may be made based on any one operation mode, or may be comprehensively determined from a plurality of operation modes. Further, it is also possible to determine whether or not the deceleration achievement request time is short by considering not only the operating mode of the accelerator operating member but also the operating mode other than the accelerator operating member, such as the presence or absence of brake operation and the brake operation amount (force). can.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing a skeleton diagram of a vehicle 10 to which the present invention is applied together with a main part of a control system. 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 an automatic transmission 14 to left and right driving wheels 18 via a differential gear device 16 . A power transmission device such as a damper device and a torque converter is provided between the engine 12 and the automatic transmission 14, but a motor generator functioning as a driving force source can also be provided.

Engine 12 includes various engine control devices 30 such as electronic throttle valves and fuel injectors required to control the output of engine 12 . The electronic throttle valve controls the amount of intake air, and the fuel injection device controls the amount of fuel supplied. The automatic transmission 14 is a stepped automatic transmission such as a planetary gear type that can establish a plurality of forward gear stages with different gear ratios depending on the engagement and release states of a plurality of hydraulic friction engagement devices (clutches and brakes). Shift control is performed by switching the disengaged states of the plurality of hydraulic friction engagement devices by means of electromagnetic hydraulic control valves, switching valves, etc. 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 has an electronic controller as a controller for controlling the output of the engine 12 via the engine control device 30 and for performing shift control for switching the forward gear stage of the automatic transmission 14 via the hydraulic control device 32. A device 40 is provided. The electronic control unit 40 includes a so-called microcomputer having a CPU, a ROM, a RAM, and an input/output interface. conduct. The electronic control unit 40 is supplied with a signal representing an accelerator operation amount .theta.acc from an accelerator operation amount sensor 50, which is the amount of depression of an accelerator pedal 52, and a signal representing an amount of depression of a brake pedal 56 from a brake operation amount sensor 54. A signal representing the braking force Brk is supplied. The accelerator operation amount .theta.acc corresponds to the required output, and the accelerator pedal 52 is an accelerator operation 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 receives information from an engine rotation speed sensor 58, an input rotation speed sensor 60, an output rotation speed sensor 62, a vehicle weight sensor 64, and a road surface gradient sensor 66, and the rotation speed of the engine 12 (engine rotation speed) Ne. Signals representing the input rotational speed Nin of the transmission 14, the output rotational speed Nout of the automatic transmission 14, the vehicle weight X, and the road 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 on the basis of seat belt use conditions, for example. The vehicle weight X and the road surface gradient Φ can also be calculated from the engine torque Te and the vehicle acceleration. In addition, various information necessary for various controls can be supplied, such as receiving the coefficient of friction μ of the road surface using an information receiving device (not shown).

The electronic control unit 40 functionally includes an engine control section 42 , a shift control section 44 , and a driving force source brake control section 46 . The engine control unit 42 basically controls the electronic throttle valve, the fuel injection device, etc. of the engine control device 30 so as to increase or decrease the output of the engine 12 according to the accelerator operation amount .theta.acc. Further, even when the vehicle is running, when the accelerator operation amount .theta.acc is 0 and the accelerator is off, a fuel cut (hereinafter also referred to as F/C) is performed to stop the fuel supply from the fuel injection device. The shift control unit 44 basically controls the hydraulic control device 32 so as to switch the forward gear stage of the automatic transmission 14 according to predetermined shift conditions. The gear shift conditions are, for example, a gear shift map defined as parameters such as the vehicle speed V and the accelerator operation amount .theta.acc. It is determined that a low gear with a large ratio can be switched.

When the accelerator pedal 52 is operated to return, the driving force source brake control unit 46 downshifts the automatic transmission 14 as necessary to increase the engine rotation speed Ne, and the pumping loss of the engine 12 is controlled. Power (driving force source brake) is applied, and signal processing is executed according to steps S1 to S10 (hereinafter simply referred to as S1 to S10) in the flow chart of FIG. The electronic control device 40 is a control device functionally having a driving force source brake control section 46 .

The flowchart in FIG. 2 is executed when the accelerator pedal 52 is operated to return while the vehicle is running. A deceleration request degree Q to be calculated. FIG. 3 is an example of a deceleration request map for calculating the deceleration request Q, which is determined using 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 as parameters. , the faster the return operation speed γ and the smaller the remaining operation amount rθ, the larger the value of the deceleration request Q becomes. The deceleration request level Q may be obtained in consideration of the return amount .DELTA..theta., which is the amount of change in the accelerator operation amount .theta.acc at the time of the return operation, the presence or absence of brake operation, and the like. Alternatively, the deceleration request level Q may be calculated according to a computational expression determined using such physical quantities as parameters.

In the next step S2, it is determined whether or not deceleration/secondary acceleration is requested depending on whether or not the deceleration request degree Q is equal to or greater than the deceleration request determination value Qs. The deceleration request determination value Qs may be set to a constant value in advance, but it may be affected by external factors such as the vehicle weight X and the road surface gradient Φ, and hardware protection such as shocks due to downshifts and overspeeding of the engine rotation speed Ne. The deceleration request determination value Qs may be corrected or limited based on a specific factor. For example, when the vehicle weight X is large or the road surface gradient Φ is large on the downward side, the vehicle 10 is difficult to decelerate. do. If the deceleration request Q is equal to or greater than the deceleration request determination value Qs, it is determined that there is a deceleration intention, and S3 and subsequent steps are executed. is judged to be absent and the process ends as it is.

In S3, the vehicle deceleration obtained by the driving force source brake in the current gear stage is calculated based on the input torque of the automatic transmission 14, the rotational load (drag, etc.) on the transmission path from the engine 12 to the drive wheels 18, and the friction coefficient of the road surface. Calculated considering μ, road surface gradient Φ, etc., converts the difference from the required deceleration (target deceleration) obtained from the deceleration requirement Q, etc. into a gear ratio, and obtains the required deceleration target gear set the steps. In S4, the current gear stage is compared with the target gear stage to determine whether downshifting is required. If downshifting is required, S5 and subsequent steps are executed.

In S5, it is determined whether downshifting to the target gear can be executed based on hardware protection and the driver's intention to decelerate. For example, if the engine rotation speed Ne after the downshift or the amount of change thereof is greater than a predetermined value, the downshift to the target gear is canceled or the target gear is restricted. The downshift to the target gear may be canceled or the target gear may be restricted based on the rotation speed of each part such as 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 to decelerate has been eliminated, and the downshift to the target gear is canceled. If the downshift is to be canceled in S5, the process is terminated, and if the downshift to the target gear stage or the restricted target gear stage is to be performed, 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 return operation of the accelerator pedal 52 . FIG. 4 is an example of a deceleration required time map for calculating the deceleration required time Td. 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 defined as parameters. The faster the return operation speed γ and the smaller the remaining operation amount rθ, the shorter the required deceleration achievement time Td. Compared to the deceleration demand map of FIG. 3, the degree of dependence on the return operation speed γ is greater. The required deceleration achievement time Td may be obtained in consideration of the return amount .DELTA..theta., which is the amount of change in the accelerator operation amount .theta.acc at the time of the return operation, the presence or absence of brake operation, and the like. Alternatively, the deceleration achievement required time Td may be calculated according to an arithmetic expression determined using such physical quantities as parameters.

In the next step S7, based on the deceleration achievement request time Td, the shift type for downshifting to the target gear is determined. In this embodiment, as shown in FIG. 5, three types of shift types are defined: first downshift control, second downshift control, and third downshift control. The first downshift control is a control that returns to fuel injection during F/C (fuel cut), performs blipping control that temporarily increases engine torque, and executes downshifts. Resume F/C accordingly. By performing the blipping control, the engine rotation speed Ne can be quickly increased, so that the downshift can be completed in a short period of time. In the second downshift control, fuel injection is resumed during F/C, and a downshift is executed with the engine 12 in an idling state. After the downshift ends, F/C is restarted as necessary. Since the engine 12 is in the idling state, it becomes easier to increase the engine rotation speed Ne, and the downshift time is shortened compared to the case where the downshift is performed in F/C. The third downshift control is a control in which a downshift is executed as it is during F/C, and since negative torque is generated in the engine 12 during F/C, the downshift time is lengthened.

Then, if the deceleration achievement request time Td is equal to or less than a predetermined first determination value T1, it is determined that the driver desires rapid deceleration, and the first downshift control is selected. If the deceleration achievement request 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), and if T1<Td<T2, the second downshift control is performed. select. Further, if the deceleration achievement request time Td is equal to or greater than the second determination value T2, the driver determines that the driver does not require such rapid deceleration and selects the third downshift control. Each of the first determination value T1 and the second determination value T2 may be set to a constant value in advance, or may be corrected according to the running state of the vehicle such as the vehicle weight X and the road surface gradient Φ. Also, it is possible to limit the types of shift that can be selected based on the running state of the vehicle. If F/C is not executed when T2≦Td, it is not necessary to execute F/C, and the second downshift control without F/C may be selected. Further, when T1<Td, without distinguishing between the second downshift control and the third downshift control, when F/C, the downshift is executed as it is in F/C, and when it is not F/C, the engine 12 downshift may be executed while the engine is idling. Further, when T1<Td, the downshift may be executed with the engine 12 always in the idling state.

At S8, downshift control is executed according to the shift type selected at S7. That is, priority is given to normal speed change control by the speed change control unit 44 to downshift to the target gear, and priority is given to normal engine control by the engine control unit 42 to stop F/C and start idling. state and perform blipping control. As a result, in the second downshift control and the third downshift control, the driving force source braking can be obtained including during the downshift control, and the target required deceleration can be obtained after the downshift ends. In the case of the first downshift control, the blipping control of the engine 12 terminates the downshift in a short period of time. , the desired deceleration can be obtained by the driving force source brake.

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

Thus, in the electronic control unit 40 of the vehicle 10 of the present embodiment, when the accelerator pedal 52 is operated to return, it is determined whether or not the required deceleration time Td is short, and if the required deceleration time Td is short, If the determination is successful (Td≦T1), the blipping control is executed when performing the downshift, so the downshift can be completed in a short period of time. As a result, the desired deceleration can be obtained quickly, the additional operation of returning the accelerator pedal 52 and the brake operation for deceleration are reduced, and the accelerator pedal 52 is re-operated immediately after deceleration. When the vehicle is to be accelerated, the gear position after the downshift can be used to accelerate quickly, and the drivability for acceleration and deceleration is improved.

In the above-described embodiment, the required deceleration time Td is calculated, and blipping control is performed when the value is equal to or less than the predetermined first judgment value T1. Instead, it may be determined whether or not the deceleration achievement request time is short, that is, whether or not to perform blipping control, directly from the operation mode when the accelerator pedal 52 is operated to return. For example, FIG. 6 shows a case where determination is made on the basis of the return operation speed γ and the remaining operation amount rθ as in the above-described embodiment. , the blipping control is executed by judging that the deceleration achievement request time requested by the driver is short.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, these are only one embodiment, and the present invention can be carried out with 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: Drive wheel 40: Electronic control device (control device) 46: Driving force source brake control section 52: Accelerator pedal (accelerator operation member) Td: Achievement of deceleration request time

Claims (1)

an automatic transmission that speeds and transmits rotation output from a driving force source to drive wheels;
an accelerator operation member operated by the driver according to the required output;
A vehicle 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 operated to return by the driver in the controller,
The driving force source brake control unit determines whether or not a deceleration achievement request time required by a driver is short based on the operation mode of the return operation when the accelerator operation member is operated to return, and determines whether the deceleration achievement request time is short or not. When it can be determined that the required time is short, blipping control is executed to temporarily increase the torque of the driving force source when performing the downshift. Execute said downshift without blipping control
A vehicle control device characterized by:

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