JP2020125823A - Control device of automatic transmission for vehicle - Google Patents

Abstract

To provide a control device of an automatic transmission for a vehicle for avoiding that wasteful gear change control is performed when a difference between a wheel speed and a vehicle speed is large.SOLUTION: As a vehicle speed V for use in the gear change control of an automatic transmission 20, there is used a gear change control vehicle speed Vs being a smaller value of either of a second estimation vehicle speed Vc2 which is obtained by adding a prescribed value α to a first estimation vehicle speed Vc1 which is calculated on the basis of vehicle acceleration G, and a wheel speed Vt. By this constitution, when the wheel speed Vt is abruptly changed due to the generation of a slip at, for example, a drive wheel 14, that is, when a difference between the wheel speed Vt and the vehicle speed V is large, the vehicle speed V for use in the gear change control of the automatic transmission 20 is switched to the second estimation vehicle speed Vc2 whose speed value is lower than the wheel speed Vt which is raised due to the generation of the slip of the drive wheel 14. Therefore, the generation of an unnecessary gear change of the automatic transmission 20 caused by an abrupt change of the wheel speed Vt can be suppressed.SELECTED DRAWING: Figure 5

Description

The present invention relates to a control device for an automatic transmission for a vehicle, and more particularly to a shift control for an automatic transmission for a vehicle.

2. Description of the Related Art There is known a control device for an automatic transmission for a vehicle, which performs a shift control based on a required load amount required for a vehicle by a driver and a vehicle speed. For example, it is a control device for an automatic transmission for a vehicle described in Patent Document 1. In the control device for an automatic transmission for a vehicle described in Patent Document 1, for example, when slippage of driving wheels occurs and the wheel speed suddenly changes and the difference between the wheel speed and the vehicle speed becomes large, it is used for gearshift control. The control is performed using the estimated vehicle speed calculated based on the vehicle acceleration as the vehicle speed. As a result, for example, it is possible to prevent useless shifting from occurring during the operation of the antilock brake control device (ABS) or the traction control control device (TRC) that brakes the slipping drive wheel.

JP 2001-099300 A

However, in the control device for an automatic transmission for a vehicle described in Patent Document 1, the vehicle speed used for the speed change control after the operation of ABS or TRC, that is, in the slip state of the drive wheels in which the difference between the wheel speed and the vehicle speed becomes large. Since the vehicle speed has been switched to the estimated vehicle speed, there is a possibility that unnecessary gear shifting has been performed at the time of switching the vehicle speed. Further, at the time of switching the vehicle speed, there is a large difference between the wheel speed and the estimated vehicle speed, it takes time to switch from the wheel speed to the estimated vehicle speed, and there is a possibility that a shock due to gear shift may occur.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an automatic transmission for a vehicle that suppresses useless shift control when the difference between the wheel speed and the vehicle speed is large. It is to provide the control device of.

The gist of the present invention is a control device for an automatic transmission for a vehicle, which performs shift control based on a required load amount required for a vehicle and a vehicle speed, wherein the vehicle speed is calculated based on the vehicle acceleration. This is to use the shift control vehicle speed which is the smaller value of the second estimated vehicle speed and the wheel speed obtained by adding a predetermined value to the first estimated vehicle speed.

According to the control device for an automatic transmission for a vehicle of the present invention, as the vehicle speed, the smaller one of the second estimated vehicle speed obtained by adding a predetermined value to the first estimated vehicle speed calculated based on the vehicle acceleration and the wheel speed, whichever is smaller. The shift control vehicle speed that is the value of is used. Thereby, for example, when the wheel speed suddenly changes due to the slip of the driving wheels, that is, when the difference between the wheel speed and the vehicle speed is large, the vehicle speed used for the shift control of the vehicle automatic transmission. Is switched to the second estimated vehicle speed having a speed value smaller than the wheel speed increased by the slip of the drive wheels. Therefore, when the difference between the wheel speed and the vehicle speed is large, it is possible to suppress the occurrence of useless shifts of the vehicle automatic transmission.

It is a figure explaining the example of schematic structure of the vehicle to which the present invention is applied, and is a figure explaining an important section of a control system by an electronic control unit, and an important section of a control function of an electronic control unit. The shift map used for shift control of the automatic transmission for vehicles of this example is shown. 6 is a time chart showing an example of an embodiment of the shift control of the vehicle automatic transmission according to the vehicle state and the vehicle state when the accelerator pedal is operated while the vehicle is traveling. FIG. 4 is a diagram in which a part of the time chart of FIG. 3 is extracted, and is a diagram illustrating a change in speed of a shift control vehicle speed used for shift control of an automatic transmission for a vehicle with a lapse of time by a bold line. 6 is a flowchart illustrating a main part of control operation of an electronic control device for controlling a shift of an automatic transmission for a vehicle based on a vehicle state.

INDUSTRIAL APPLICABILITY The present invention is applied to an engine-driven vehicle including an engine as a driving force source for traveling, a hybrid vehicle having a traveling rotating machine, that is, a driving electric motor in addition to the engine as a driving force source for traveling, an electric vehicle, and the like. .. Further, the present invention can be applied to an electric vehicle equipped with only an electric motor as a driving force source.

An embodiment of the present invention will be described in detail below with reference to the drawings. It should be noted that in the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the respective parts are not necessarily drawn accurately.

FIG. 1 is a diagram illustrating a schematic configuration of a vehicle 10 to which the present invention is applied, and is a diagram illustrating a main portion of a control function and a main portion of a control system of an electronic control unit 70 included in the vehicle 10. is there. The vehicle 10 includes an engine 12 as a driving force source, driving wheels 14, and a power transmission device 16 that transmits the driving force of the engine 12 to the driving wheels 14. As the engine 12, for example, a gasoline engine or a diesel engine that generates a driving force, that is, a torque by burning fuel is used. In the engine 12, the driving force, that is, the output torque is controlled by the electronic control device 70 by the driver according to the accelerator opening degree θacc corresponding to the required load amount on the vehicle 10.

The power transmission device 16 includes a torque converter 18, an automatic transmission 20 for a vehicle (hereinafter referred to as an automatic transmission 20), a differential gear device 24 connected to an output rotating member 22 of the automatic transmission 20, and a differential gear device 24. And a pair of left and right axles 26 and the like connected to each other. The output rotary member 22 is, for example, the output shaft of the automatic transmission 20. In the power transmission device 16, the driving force output from the engine 12 is transmitted to the torque converter and the automatic transmission 20, and is transmitted from the output rotary member 22 of the automatic transmission 20 to the drive wheels 14 via the differential gear device 24 and the like. Transmitted. The automatic transmission 20 is, for example, a planetary gear type automatic transmission, a synchromesh parallel two-shaft automatic transmission, or a synchromesh parallel two-shaft automatic transmission having two input shafts. A belt type continuously variable transmission is used. In this embodiment, a stepped automatic transmission is used.

The vehicle 10 includes an electronic control device 70 that is a control device that controls each unit related to traveling of the vehicle 10. The electronic control unit 70 is configured to include a so-called microcomputer provided with, for example, a CPU, a RAM, a ROM, an input/output interface, etc., and the CPU uses a temporary storage function of the RAM while following a program stored in the ROM in advance. Various controls of the vehicle 10 are executed by performing signal processing.

The electronic control unit 70 is supplied with various input signals detected by various sensors of the vehicle 10. For example, the output shaft rotation speed No (rpm) corresponding to the vehicle speed V (km/h) and the accelerator opening θacc( based on the detection signals from the output shaft rotation speed sensor 30, the accelerator opening sensor 32, the vehicle G sensor 34, etc. %), the acceleration G (km/h ² ) in the front-rear direction of the vehicle 10 and the like are respectively supplied. Further, the electronic control unit 70 includes an engine rotation speed (rpm), an input shaft rotation speed (rpm), a throttle valve based on detection signals from an engine rotation speed sensor (not shown), an input shaft rotation speed sensor, a throttle opening sensor, and the like. The opening degree (%) and the like are respectively supplied.

The electronic control unit 70 outputs an engine output control signal Spu for controlling the output of the engine 12, a hydraulic control command signal Spt for controlling the shift of the automatic transmission 20, and the like.

As shown in FIG. 1, the electronic control unit 70 includes an output rotation speed detecting unit, that is, an output rotation speed detecting unit 80, a wheel speed calculating unit, that is, a wheel speed calculating unit 82, and a first estimated vehicle speed, as essential parts of the control function. The calculation means or first estimated vehicle speed calculation section 84, the second estimated vehicle speed calculation means or second estimated vehicle speed calculation section 86, the shift control vehicle speed determination means or shift control vehicle speed determination section 88, and the shift control means or shift control section 90 are functional. Be prepared for.

The output rotation speed detector 80 detects the output shaft rotation speed No of the automatic transmission 20, for example, the rotation speed No of the output rotation member 22 by the output shaft rotation speed sensor 30.

The wheel speed calculation unit 82 calculates the rotation speed of the drive wheels 14, that is, the wheel speed Vt, based on the output shaft rotation speed No detected by the output rotation speed detection unit 80. Specifically, the wheel speed Vt is calculated based on the calculation formula represented by No/γ×2πR. Here, γ is the differential ratio of the differential gear device 24, and R is the radius of the drive wheel 14. Further, in the present embodiment, the wheel speed Vt is calculated based on the above calculation formula, but the wheel speed based on the detection signal from a wheel speed sensor (not shown) provided on the drive wheel 14 may be used, for example.

The first estimated vehicle speed calculation unit 84 calculates the first estimated vehicle speed Vc1 based on the wheel speed Vt calculated by the wheel speed calculation unit 82. Specifically, the first estimated vehicle speed Vc1 is calculated based on the calculation formula represented by Vt0+G·Δt. Here, Vt0 is, for example, a preset initial value of the wheel speed. The first estimated vehicle speed Vc1 is a total value of an initial value Vt0 of the wheel speed and a value obtained by integrating the vehicle acceleration G detected by the vehicle G sensor 34 with time.

The second estimated vehicle speed calculation unit 86 calculates the second estimated vehicle speed Vc2 based on the first estimated vehicle speed Vc1 calculated by the first estimated vehicle speed calculation unit 84. Specifically, the second estimated vehicle speed Vc2 is calculated based on the calculation formula represented by Vc1+α. Here, α is a predetermined value that is experimentally or designed in advance, and is set to a value that is larger than the calculation variation in the first estimated vehicle speed calculation unit 84.

The shift control vehicle speed determination unit 88 is used for shift control of the automatic transmission 20 based on the wheel speed Vt calculated by the wheel speed calculation unit 82 and the second estimated vehicle speed Vc2 calculated by the second estimated vehicle speed calculation unit 86. The speed change control vehicle speed Vs as the vehicle speed V to be controlled is determined. Specifically, the minimum select MIN (Vt, Vc2) of the wheel speed Vt and the second estimated vehicle speed Vc2 is performed, and the smaller value of the wheel speed Vt and the second estimated vehicle speed vc2 is used as the speed change control vehicle speed. Determine to Vs.

The shift control unit 90 controls the shift of the automatic transmission 20 based on a shift map that is experimentally or designed in advance. Specifically, the shift control unit 90 determines an accelerator opening degree θacc as a required load amount required by the driver for the vehicle 10 or the engine 12 and a vehicle speed V used for determining the shift control of the automatic transmission 20. The shift control of the automatic transmission 20 is performed based on the shift map F(θacc, Vs) set by the shift control vehicle speed Vs. That is, the shift control unit 90 executes the shift of the automatic transmission 20 based on the vehicle state indicated by the shift map F(θacc, Vs) preset with the accelerator opening θacc and the shift control vehicle speed Vs as variables. The shift stage to be performed is determined, and shift control is executed.

FIG. 2 shows a shift map F(θacc, Vs) used for shift control of the automatic transmission 20 of this embodiment. The vertical axis represents the accelerator opening θacc, and the horizontal axis represents the shift control vehicle speed Vs. The solid line in FIG. 2 indicates an upshift line preset with the accelerator opening θacc and the shift control vehicle speed Vs as variables. For example, when the vehicle state is the accelerator opening θaccex at point A in FIG. 2 and the shift control vehicle speed Vsa, the accelerator opening θaccex at point B in FIG. 2 does not change and the shift control vehicle speed Vs is lower than the shift control vehicle speed Vsa. When the shift control vehicle speed Vsb changes to a larger value, the automatic transmission 20 is upshifted from the shift stage N to the shift stage N+1. The shift map F is switched to a high-speed forward gear having a small gear ratio as the shift control vehicle speed Vs increases, and to a low-speed forward gear having a large gear ratio as the accelerator opening θacc increases. It is set.

FIG. 3 is a time chart showing an example of an embodiment of shift control of the automatic transmission 20 according to the vehicle state and the vehicle state when the driver operates the accelerator pedal while the vehicle 10 is traveling. Specifically, FIG. 3 shows the speed changes of the wheel speed Vt, the first estimated vehicle speed Vc1 and the second estimated vehicle speed Vc2 when the accelerator pedal is operated, and the vehicle speed used for the shift control of the automatic transmission 20. V, that is, an embodiment of the shift control of the automatic transmission 20 based on the shift control vehicle speed Vs. In the time chart of FIG. 3, the operation amount of the accelerator pedal, the speed value, and the shift speed are shown in order from the paper surface.

In the time chart of FIG. 3, a solid line showing a relationship between time and a speed value is a line showing a speed change with time of the wheel speed Vt, and a broken line is a line showing a speed change of the first estimated vehicle speed Vc1 with time. The alternate long and short dash line is a line indicating a change in speed of the second estimated vehicle speed Vc2 with respect to time. Further, in the time chart of FIG. 3, the solid line showing the relationship between time and the shift speed is a line showing the mode of shifting the shift speed according to the present embodiment, and the two-dot chain line is the comparative example, that is, the shift control vehicle speed. 8 is a line showing an embodiment of gear shifting of a shift stage by a conventional control device for an automatic transmission for a vehicle in which Vs is a wheel speed Vt. FIG. 4 is a diagram in which a part of the time chart of FIG. 3 is extracted, and is a diagram showing a change in speed of the shift control vehicle speed Vs used for shift control of the automatic transmission 20 with time as a bold line. The speed changes of the wheel speed Vt, the first estimated vehicle speed Vc1, and the second estimated vehicle speed Vc2 shown in FIG. 4 over time are the same as the speed changes shown in FIG.

In FIG. 3, time t1 indicates the time when the driver operates the accelerator pedal while the vehicle 10 is traveling. In the present embodiment, the vehicle 10 is traveling at a constant wheel speed Vt1 and a first estimated vehicle speed Vc1 until the accelerator pedal is operated, for example. After time t1, as shown in FIG. 3, the wheel speed Vt, the first estimated vehicle speed Vc1 and the second estimated vehicle speed Vc2 increase in proportion to the passage of time due to the operation of the accelerator pedal. As shown in FIG. 3, the increase amount of the wheel speed Vt over time is larger than the increase amount of the first estimated vehicle speed Vc1 and the second estimated vehicle speed Vc2 over time. That is, the wheel speed Vt suddenly changes due to, for example, the slip of the driving wheels 14 caused by the operation of the accelerator pedal, and the time elapses in the speed change between the wheel speed Vt and the first estimated vehicle speed Vc1 and the second estimated vehicle speed Vc2. There is a divergence in the speed value for each.

In FIG. 3, a time point t2 indicates a time point when the shift control vehicle speed Vs is switched. Specifically, the time point t2 indicates a time point when the wheel speed Vt that has suddenly changed due to the slip of the drive wheels 14 becomes larger than the second estimated vehicle speed Vc2. It shows the time when minimum selection of Vt and the second estimated vehicle speed Vc2r is performed. Since the wheel speed Vt, the first estimated vehicle speed Vc1 and the second estimated vehicle speed Vc2 are constantly calculated, the shift control vehicle speed Vs is automatically changed from the wheel speed Vt to the second estimated vehicle speed Vc2 when the drive wheels 14 slip, for example. Is switched to.

In FIG. 3, time t3 indicates the time when the automatic transmission 20 is shifted in the comparative example. Specifically, at time t3, the shift control vehicle speed Vs with respect to the accelerator opening θacc based on the driver's operation of the accelerator pedal is a predetermined value indicated by the upshift line of the preset shift map F(θacc, Vs). It is the time when the shift stage N of the automatic transmission 20 is shifted to the shift stage N+1 by reaching the shift determination vehicle speed Vin. Here, the gear shift determination vehicle speed Vin is a value determined from the gear shift map F(θacc, Vs). For example, the gear shift determination vehicle speed Vin corresponding to a predetermined accelerator opening θaccex is the gear shift at point B shown in FIG. The control vehicle speed becomes Vsb.

In FIG. 3, time t4 indicates the time when the automatic transmission 20 is shifted in the present embodiment. Specifically, at time t4, the shift control vehicle speed Vs with respect to the accelerator opening degree θacc reaches a predetermined value indicated by the upshift line of the shift map F(θacc, Vs), that is, the shift determination vehicle speed Vin, so that the automatic shift stage 20 It is the time when the shift stage N is shifted to the shift stage N+1. In the present embodiment, the shift control vehicle speed Vs is determined by the shift control vehicle speed determination unit 88 performing minimum selection between the wheel speed Vt and the second estimated vehicle speed Vc2, and therefore is shown in FIGS. 3 and 4. As described above, the shift of the automatic transmission 20 is performed with a delay of the time difference td as compared with the comparative example. That is, in the present embodiment, when the drive wheels 14 slip and the wheel speed Vt suddenly changes, the shift control vehicle speed Vs is smaller than that in the comparative example, for example, the shift map F (θacc, Vs) shown in FIG. In, the shift from the value indicated by the point A which is the shift stage N to the value indicated by the point B on the upshift line for shifting from the shift stage N to the shift stage N+1 is suppressed. Therefore, useless shifting of the automatic transmission 20 after the slip of the drive wheels 14 is suppressed, and the optimum gear stage in the vehicle state is realized.

FIG. 5 is a flowchart for explaining a main part of the control operation of the electronic control unit 70 for controlling the shift of the automatic transmission 20 based on the state of the vehicle 10, and is repeatedly executed at all times.

In step S10 (hereinafter, step is omitted) corresponding to the output rotation speed detection unit 80, the output shaft rotation speed sensor 30 detects the output shaft rotation speed No of the automatic transmission 20. When the output rotation speed detection unit 80 detects the output shaft rotation speed No of the automatic transmission 20, S20 corresponding to the wheel speed calculation unit 82 is executed.

In S20 corresponding to the wheel speed calculator 82, the wheel speed Vt is calculated based on the output shaft rotation speed No detected by the output rotation speed detector 80. When the wheel speed calculation unit 82 calculates the wheel speed Vt, S30 corresponding to the first estimated vehicle speed calculation unit 84 is executed.

In S30 corresponding to the first estimated vehicle speed calculation unit 84, the first estimated vehicle speed Vc1 is calculated based on the wheel speed Vt calculated by the wheel speed calculation unit 82. When the first estimated vehicle speed Vc1 is calculated by the first estimated vehicle speed calculation unit 84, S40 corresponding to the second estimated vehicle speed calculation unit 86 is executed.

In S40 corresponding to the second estimated vehicle speed calculation unit 86, the second estimated vehicle speed Vc2 is calculated based on the first estimated vehicle speed Vc1 calculated by the first estimated vehicle speed calculation unit 84. When the second estimated vehicle speed calculation unit 86 calculates the second estimated vehicle speed Vc2, S50 corresponding to the shift control vehicle speed determination unit 88 is executed.

In S50 corresponding to the shift control vehicle speed determination unit 88, the wheel speed Vt and the wheel speed Vt are calculated based on the wheel speed Vt calculated by the wheel speed calculation unit 82 and the second estimated vehicle speed Vc2 calculated by the second estimated vehicle speed calculation unit 86. The smaller one of the two estimated vehicle speeds Vc2, that is, the minimum selected value is determined as the shift control vehicle speed Vs. When the shift control vehicle speed Vs is determined by the shift control vehicle speed determination unit 88, S60 corresponding to the shift control unit 90 is executed.

In S60 corresponding to the shift control unit 90, shift control of the automatic transmission 20 is executed based on a preset shift map F(θacc, Vs). That is, based on the vehicle state shown in the shift map F(θacc, Vs) by the shift control vehicle speed Vs determined by the shift control vehicle speed determination unit 88 and the accelerator opening θacc detected by the accelerator opening sensor 32, the target shift is performed. It is determined that the gear is established, and the shift control for establishing the target gear is executed. This routine is ended after the shift control of the automatic transmission 20 is executed.

As described above, according to the control device 70 of the automatic transmission 20 of the present embodiment, the vehicle speed V used for the shift control of the automatic transmission 20 is set to the first estimated vehicle speed Vc1 calculated based on the vehicle acceleration G. The shift control vehicle speed Vs, which is the smaller value of the second estimated vehicle speed Vc2 and the wheel speed Vt obtained by adding the value α, is used. Thus, for example, when the wheel speed Vt suddenly changes due to slippage of the drive wheels 14, that is, when the difference between the wheel speed Vt and the vehicle speed V is large, the vehicle speed V used for the shift control of the automatic transmission 20 is The vehicle speed is switched to the second estimated vehicle speed Vc2, which has a smaller speed value than the wheel speed Vt increased due to the slip of the drive wheels 14. Therefore, it is possible to suppress the occurrence of unnecessary gear shift of the automatic transmission 20 due to a sudden change in the wheel speed Vt.

The preferred embodiment of the present invention has been described in detail above with reference to the drawings, but the present invention is not limited to this, and can be implemented in still another mode.

For example, in the above-described embodiment, the automatic transmission 20 is gearshift-controlled based on the accelerator opening degree θacc and the gearshift control vehicle speed Vs, but the invention is not limited to this, and the driver's vehicle 10, that is, the engine 12 is requested. The automatic transmission 20 is shift-controlled based on the throttle valve opening and the shift control vehicle speed Vs by using the throttle valve opening and the fuel injection amount for the engine 12 as the required load amount. Good. That is, the shift control of the automatic transmission 20 may be performed based on a shift map preset with the throttle valve opening and the shift control vehicle speed Vs as variables.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the above description is merely one embodiment, and the other embodiments will not be illustrated, but the present invention is within the scope of a person skilled in the art without departing from the spirit thereof. It can be implemented in a mode in which various changes and improvements are added based on knowledge.

10: Vehicle 20: Automatic transmission 70 for vehicle: Electronic control device V: Vehicle speed θacc: Accelerator opening (request load amount)
G: vehicle acceleration Vc1: first estimated vehicle speed α: predetermined value Vc2: second estimated vehicle speed Vt: wheel speed Vs: shift control vehicle speed

Claims (1)

A control device for an automatic transmission for a vehicle, which performs shift control based on a required load amount required for a vehicle and a vehicle speed,
As the vehicle speed, a shift control vehicle speed that is the smaller value of the second estimated vehicle speed obtained by adding a predetermined value to the first estimated vehicle speed calculated based on the vehicle acceleration and the wheel speed is used. Control device for automatic transmission.

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