JP5116702B2 - Shift control device for automatic transmission - Google Patents

Description

  The present invention relates to a shift control device for an automatic transmission, and more particularly to a device that performs downshift control in accordance with vehicle acceleration during deceleration.

An automatic transmission mounted on a vehicle such as an automobile includes a shift control device that selects an appropriate shift stage based on the driving state of the vehicle. The shift control device includes a shift map (shift diagram) in which a shift stage is selected according to parameters such as a vehicle speed and a throttle opening, and performs shift control based on the shift map.
The shift control device performs so-called adaptive control that shifts according to the driver's intention such as acceleration / deceleration. In adaptive control, for example, when a driver performs a braking operation when entering a curved road, etc., downshifting is performed in accordance with the deceleration of the vehicle to increase the effectiveness of engine braking, and the driving force during reacceleration is increased. There is braking control to ensure.

  As an example of conventionally known adaptive control, for example, Patent Document 1 describes a technique in which a vector value obtained by combining lateral acceleration and longitudinal acceleration of a vehicle is used as a shift determination value. This shift control device performs prohibition or permission of upshifting, execution of downshifting, and the like by determining in which of a plurality of predetermined determination areas the shift determination value is included.

JP 2007-177966 A

In the case of a shift control device that permits downshifting when a shift determination value obtained based on vehicle acceleration exceeds a threshold, even if the total deceleration amount within a predetermined time does not change, how to operate the driver As a result, the downshift permission cannot be determined, and control may be uneven.
For example, if the driver's brake operation is uneven and the change in the deceleration G is large, the downshift permission determination is performed when the peak value exceeds the threshold value. If the peak value does not reach the threshold value, the downshift permission determination may not be established even though the deceleration amount within the predetermined time is the same. Specifically, the initial stepping on the brake by the driver is weak and a downshift is performed when the driver feels that the deceleration is insufficient and the pedal is increased strongly.However, when obtaining the same amount of deceleration, the driver applies the appropriate braking operation from the beginning. If done, it may not be downshifted.
An object of the present invention is to provide a shift control device for an automatic transmission that performs an appropriate downshift even when there is a variation in the operation of a driver.

The present invention solves the above-described problems by the following means.
The invention according to claim 1 is a shift control device for performing shift control of an automatic transmission, and calculates a shift determination value based on acceleration calculation means for calculating vehicle acceleration and acceleration calculated by the acceleration calculation means. A shift determination value calculating means, a shift determination value differentiating means for differentiating the shift determination value calculated by the shift determination value calculating means, and a differential value of the shift determination value obtained by the shift determination value differentiating means having a threshold value. Shift control means for permitting a downshift of the automatic transmission when exceeding, and for prohibiting the downshift when a differential value of the shift determination value is less than the threshold value. This is a gear shift control device for a machine.

  The invention according to claim 2 is a shift control device for performing shift control of an automatic transmission, and calculates a shift determination value based on acceleration calculation means for calculating vehicle acceleration and acceleration calculated by the acceleration calculation means. The shift determination value calculating means, the shift determination value integrating means for integrating the shift determination value calculated by the shift determination value calculating means, and the integral value of the shift determination value obtained by the shift determination value integrating means has a threshold value. Shift control means for permitting a downshift of the automatic transmission when exceeding, and for prohibiting the downshift when an integral value of the shift determination value is less than the threshold value. This is a gear shift control device for a machine.

According to a third aspect of the present invention, the acceleration calculating means includes a longitudinal acceleration calculating means for calculating the longitudinal acceleration of the vehicle and a lateral acceleration calculating means for calculating the lateral acceleration of the vehicle, and increases the lateral acceleration. 3. The automatic shift according to claim 1, further comprising a correction unit that corrects at least one of the shift determination value and the threshold value so that the downshift permission is not easily established. This is a gear shift control device for a machine.
According to a fourth aspect of the present invention, the shift determination value calculating means is a vector obtained by combining the longitudinal acceleration calculated by the longitudinal acceleration calculating means and the lateral acceleration calculated by the lateral acceleration calculating means. The shift control device for an automatic transmission according to claim 3, wherein the shift determination value is calculated based on the shift determination value.

According to a fifth aspect of the present invention, the correcting means changes the shift determination value calculated by the shift determination value calculating means based on the scalar quantity of the vector according to the transition of the vector direction from the front-rear direction to the horizontal direction. 5. The shift control device for an automatic transmission according to claim 4, wherein the shift control device corrects to decrease.
The invention according to claim 6 is characterized in that the correction means corrects the threshold value so as to increase as the direction of the vector changes from the front-rear direction to the horizontal direction. A transmission control apparatus for a transmission.

According to the present invention, the following effects can be obtained.
(1) Even if the shift determination value does not exceed the corresponding threshold value by allowing downshift when the differential value of the shift determination value calculated based on the acceleration of the vehicle exceeds the threshold value, for example, When the start-up of the deceleration G or the like is fast, downshift can be executed and appropriate shift control can be performed. As a result, the occurrence of uneven shifting can be suppressed and a natural drive feeling can be obtained.
(2) Even if the shift determination value does not exceed the corresponding threshold value by allowing downshift when the integral value of the shift determination value calculated based on the acceleration of the vehicle exceeds the threshold value, for example, When the total amount of deceleration within a predetermined period is large, a downshift can be executed and appropriate shift control can be performed. This also suppresses the occurrence of uneven shifting, and a natural drive feeling can be obtained.
(3) By correcting at least one of the shift determination value and the threshold so that it is difficult to permit downshifting according to the increase in lateral acceleration, the lateral acceleration due to cornering is large, and the tire has a frictional circle limit. When the remaining force of the longitudinal force that can be generated within the range of values is insufficient, the downshift can be suppressed to prevent the vehicle behavior from being disturbed by the tire slip, and the steering stability can be improved.
(4) By calculating a shift determination value based on a vector obtained by combining the longitudinal acceleration and the lateral acceleration, a shift determination value capable of appropriately evaluating the longitudinal force and lateral force of the tire with respect to the friction circle limit value is obtained. Thus, appropriate shift control can be performed.
(5) The shift determination value calculated on the basis of the vector scalar quantity is corrected so as to decrease as the vector direction changes from the front-rear direction to the horizontal direction. ) Can be obtained.
(6) The effect of the above item (4) can also be obtained by a simple process by correcting the threshold value to increase as the vector direction changes from the front-rear direction to the horizontal direction.

1 is a schematic diagram showing a system configuration of an automatic transmission having Embodiment 1 of a shift control device to which the present invention is applied. FIG. It is a figure which shows an example of the shift map in the shift control apparatus of FIG. It is a flowchart which shows the operation | movement at the time of braking control in the transmission control apparatus of FIG. 3 is a graph showing an example of a shift of a shift determination value in the shift control device of FIG. 6 is a graph showing a transition of a differential value of a shift determination value in the case of FIG. 6 is a graph showing another example of a shift of a shift determination value in the shift control device of FIG. 1. It is a graph which shows transition of the differential value of the shift determination value in the case of FIG. It is a graph which shows the integral value of the shift determination value in the case of FIG. It is a schematic diagram which shows the system configuration | structure of the automatic transmission which has Example 2 of the transmission control apparatus to which this invention is applied. 10 is a flowchart showing an operation of braking control in the transmission control device of FIG. 9.

  The present invention addresses the problem of providing a shift control device for an automatic transmission that performs an appropriate downshift even when there is a variation in driver operation, in the amount of scalar of the combined vector of longitudinal acceleration and lateral acceleration of the vehicle. This is solved by downshifting when the differential value and the integral value of the shift determination value calculated based on the threshold value exceed the threshold value.

A first embodiment of a shift control apparatus for an automatic transmission to which the present invention is applied will be described below.
The automatic transmission according to the first embodiment is mounted on an automobile such as a passenger car.
FIG. 1 is a schematic diagram illustrating a system configuration of the automatic transmission according to the first embodiment.
The vehicle includes an engine 10, an automatic transmission 20, a transmission control unit (TCU) 30, a road surface μ estimation device 40, a road surface gradient estimation device 50, and the like.

The engine 10 is, for example, a gasoline engine that performs output adjustment using a throttle valve.
The engine 10 includes an intake system including an air cleaner 11, an air flow meter 12, an intake duct 13, a throttle body 14, an intake manifold 15, and the like, and a throttle opening sensor 16 is provided in the throttle body 14.

The air cleaner 11 introduces outside air as air (fresh air) used for combustion of the engine 10 and removes foreign matters by filtering with an air cleaner element having, for example, a nonwoven fabric.
The air flow meter 12 measures the flow rate of fresh air from the air cleaner 11 and transmits it to an engine control unit (ECU) (not shown).
The intake duct 13 is an intake pipe that introduces fresh air from the air flow meter 12 into the throttle body 14.

The throttle body 14 includes a throttle valve that controls the intake air amount of the engine 10. The throttle valve is driven by an actuator (not shown) according to an accelerator pedal operation by a driver, for example.
The intake manifold 15 is a branch pipe that distributes fresh air from the throttle body 14 to the intake ports of the cylinders provided in the cylinder head of the engine 10 body.
The throttle opening sensor 16 detects the opening of the throttle valve in the throttle body 14 and transmits a signal related to the opening to the TCU 30. The TCU 30 calculates the throttle opening used for the shift control of the automatic transmission 20 based on the output signal of the throttle opening sensor 16.

The automatic transmission 20 includes a torque converter 21, a transmission mechanism unit 22, a propeller shaft 23, a hydraulic circuit unit 24, a solenoid valve 25, a vehicle speed sensor 26, an inhibitor switch 27, and the like.
The torque converter 21 is a fluid coupling with a lockup mechanism provided between the flywheel of the engine 10 and the input shaft portion of the speed change mechanism portion 22.
The speed change mechanism unit 22 has a plurality of planetary gear sets such as three rows, and a plurality of fastening elements such as brakes and clutches, and performs, for example, five forward speeds and one reverse speed.
The propeller shaft 23 is a rotating shaft that transmits power from the automatic transmission 20 to a rear differential (not shown).

The hydraulic circuit unit 24 includes a fluid passage that supplies hydraulic oil (ATF) pressurized by an oil pump (not shown) to each fastening element of the transmission mechanism unit 22.
A plurality of solenoid valves 25 are provided in the hydraulic circuit section 24 and perform switching of the hydraulic circuit based on a control signal from the TCU 30.
The vehicle speed sensor 26 includes a Hall element type sensor, for example, and generates a pulse signal corresponding to the peripheral speed of the propeller shaft 23. The TCU 30 calculates the traveling speed (vehicle speed) of the vehicle used for the shift control based on the pulse signal.
The inhibitor switch 27 detects the range position of the transmission mechanism 22 and transmits it to the TCU 30.

The TCU 30 is an information processing apparatus that comprehensively controls the above-described automatic transmission 20, and includes a CPU, a ROM, a storage means such as a RAM, an input / output interface, and the like. The TCU 30 controls various clutches, brakes, and the like in the automatic transmission 20 to perform shift control, and also performs known lockup control, line pressure control, and the like. The TCU 30 functions as a transmission control device according to the present invention.
A longitudinal acceleration sensor 31 and a lateral acceleration sensor 32 are connected to the TCU 30.
The longitudinal acceleration sensor 31 and the lateral acceleration sensor 32 include, for example, a MEMS-based acceleration pickup that generates an output signal corresponding to the acceleration in each direction acting on the vehicle.

The TCU 30 includes a longitudinal acceleration calculation means 33, a lateral acceleration calculation means 34, a vector calculation means 35, a shift determination value calculation means 36, a shift determination value differentiation means 37, a shift determination value integration means 38, a shift control means 39, and the like. ing.
Each of these means may have a configuration having independent hardware, or may be realized by software using common hardware.

The longitudinal acceleration calculating means 33 and the lateral acceleration calculating means 34 calculate the longitudinal acceleration Gx and the lateral acceleration Gy acting on the vehicle based on the output signals of the longitudinal acceleration sensor 31 and the lateral acceleration sensor 32, respectively.
Note that the output value of the longitudinal acceleration sensor 31 includes not only the acceleration / deceleration of the vehicle but also the influence of the gradient in the longitudinal direction of the road surface. Therefore, the longitudinal acceleration calculation means 33 calculates the road surface gradient estimated by the road gradient estimation device 50. Perform correction calculation to eliminate the influence.

The vector calculation means 35 combines the longitudinal acceleration Gx and the lateral acceleration Gy calculated by the longitudinal acceleration calculation means 33 and the lateral acceleration calculation means 34, respectively, and calculates an acceleration vector Cvec acting on the vehicle. The acceleration vector Cvec is expressed by a scalar quantity Ve and an angle θv with respect to the vehicle traveling direction.
The scalar quantity Ve is obtained by the following equation 1.

Ve = (Gx ² + Gy ² ) ^1/2 (Formula 1)

Further, the angle θv is obtained by the following equation 2.

θv = arctan (Gx / Gy) (Formula 2)

The shift determination value calculation means 36 corrects the scalar quantity Ve of the acceleration vector Cvec calculated by the vector calculation means 35 based on the angle θv, and calculates the shift determination value Cs.
In this correction, for example, the scalar quantity Ve is multiplied by a gain G (θv) set to decrease in accordance with an increase in the angle θv (increase in the lateral acceleration Gy component). That is, the shift determination value Cs is obtained by the following equation 3.

Cs = G (θv) · Ve (Formula 3)

As a result, when the lateral acceleration Gy is large, even if the scalar amount Ve, which is the magnitude of the acceleration acting on the vehicle, is the same, the shift determination value Cs becomes small, and the downshift determination described later is difficult to be established. It has become.
That is, the shift determination value calculation unit 36 in the first embodiment also functions as a correction unit that corrects the shift determination value so that the downshift determination is difficult to be established according to the increase in the lateral acceleration Gy.

The shift determination value differentiating unit 37 calculates a differential value obtained by differentiating the shift determination value Cs calculated by the shift determination value calculating unit 36 with respect to time.
The shift determination value integration means 38 holds the history of the shift determination value Cs calculated by the shift determination value calculation means 36 within the past predetermined period, and calculates the integral value of the shift determination value Cs in this predetermined period. It is.

  The shift control means 39 performs normal shift control based on the vehicle speed and the throttle opening, and determines whether or not to execute downshift in the braking control using the shift determination value and its differential value and integral value. It is. The shift control means 39 controls the solenoid valve 25 to cause the transmission mechanism unit 22 to perform a downshift when the execution of the downshift is determined. This braking control will be described in detail later.

Further, a road surface μ estimation device 40 and a road surface gradient detecting means 50 are connected to the TCU 30.
The road surface μ estimation device 40 estimates a friction coefficient (μ) of a road surface on which the vehicle is traveling. The road surface μ estimation device 40 extends the cornering power (CP) of the front and rear wheels to a non-linear region based on the equation of motion of the lateral movement of the vehicle using, for example, various travel parameters such as vehicle speed, steering angle, and actual yaw rate. presume. Then, the road surface μ estimation device 40 estimates the road surface μ based on the ratio of the estimated CP to the equivalent CP on the high μ road of the front and rear wheels. Such estimation of the road surface μ is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-2274 related to the applicant's past patent application.
The road surface gradient detecting means 50 calculates an estimated longitudinal acceleration of the vehicle based on a change in the vehicle speed obtained based on the output transition of the vehicle speed sensor 26, and calculates the estimated longitudinal acceleration based on the output of the longitudinal acceleration sensor 31. By comparing with the longitudinal acceleration, the gradient in the longitudinal direction of the road surface on which the vehicle is traveling is detected.

Next, the shift control of the automatic transmission 20 in the TCU 30 of the first embodiment will be described.
First, during normal travel where the longitudinal acceleration and lateral acceleration acting on the vehicle are relatively small, the shift control is executed based on a preset shift map.
FIG. 2 is an example of a shift map in the first embodiment. In FIG. 2, the horizontal axis indicates the vehicle speed, and the vertical axis indicates the throttle opening. In FIG. 2, the shift diagram on the upshift side is indicated by a solid line, and the shift diagram on the downshift side is indicated by a dotted line.
As shown in FIG. 2, the shift map defines shift stages to be selected according to, for example, the vehicle traveling speed (vehicle speed) and the throttle opening. In the shift map, so-called hysteresis control is performed by arranging the shift diagram on the upshift side on the higher speed side than the shift diagram on the downshift side.
Usually, a plurality of types of such shift maps are prepared and switched according to the driving state of the vehicle and the selection operation from the driver.

Further, the TCU 30 according to the first embodiment performs the braking control described below as one of so-called adaptive controls. This braking control is executed when the driver's brake operation is detected, for example, when a brake lamp switch is turned on when the driver depresses the brake pedal.
FIG. 3 is a flowchart showing the operation of the TCU 30 when performing the braking control. Hereinafter, the steps will be described step by step.

<Step S01: Longitudinal acceleration calculation>
The longitudinal acceleration calculating means 33 calculates the longitudinal acceleration Gx based on the output signal of the longitudinal acceleration sensor 31.
Thereafter, the process proceeds to step S02.

<Step S02: Lateral acceleration calculation>
The lateral acceleration calculation means 34 calculates the lateral acceleration Gy based on the output signal of the lateral acceleration sensor 32.
Thereafter, the process proceeds to step S03.

<Step S03: Acceleration vector calculation>
The vector calculation means 35 calculates the scalar quantity Ve and the angle θv of the acceleration vector Cvec using the above-described Expression 1 and Expression 2.
Thereafter, the process proceeds to step S04.

<Step S04: Shift Determination Value Calculation>
The shift determination value calculation means 36 calculates the shift determination value Cs by correcting the scalar quantity Ve of the acceleration vector Cvec calculated by the vector calculation means 35 with a gain that changes according to the angle θv, using the above-described equation 3. .
Thereafter, the process proceeds to step S05.

<Step S05: Shift Determination Value Differentiation Process>
The shift determination value differentiating unit 37 calculates a differential value ΔCs obtained by differentiating the shift determination value Cs calculated by the shift determination value calculating unit 36 with respect to time.
Thereafter, the process proceeds to step S06.

<Step S06: Shift Determination Value Integration Process>
The shift determination value integration unit 38 calculates an integrated value ICs obtained by integrating the shift determination value Cs calculated by the shift determination value calculation unit 36 over a predetermined period in the past.
Thereafter, the process proceeds to step S07.

<Step S07: Shift Determination Based on Shift Determination Value>
The shift control means 39 determines whether the shift determination value Cs is greater than or equal to a preset shift shift determination threshold value. If the shift determination value Cs is equal to or greater than the downshift determination threshold, the process proceeds to step S11. On the other hand, if the shift determination value Cs is less than the downshift determination threshold, the process proceeds to step S10.

<Step S08: Shift Determination Based on Shift Determination Value Differential Value>
The shift control means 39 determines whether or not the shift determination value differential value ΔCs is equal to or greater than a preset shift determination value differential downshift determination threshold (downshift differential value determination threshold). If the shift determination value differential value ΔCs is equal to or greater than the downshift differential value determination threshold value, the process proceeds to step S11. On the other hand, if the shift determination value differential value ΔCs is less than the downshift differential value determination threshold value, the process proceeds to step S10.

<Step S09: Shift Determination by Shift Determination Value Integrated Value>
The shift control means 39 determines whether or not the shift determination value integrated value ICs is equal to or greater than a preset downshift determination threshold (downshift integral value determination threshold) of the shift determination value integrated value. If the shift determination value integrated value ICs is equal to or greater than the downshift integrated value determination threshold, the process proceeds to step S11. On the other hand, if the shift determination value integrated value ICs is less than the downshift integrated value determination threshold, the process proceeds to step S10.
The downshift determination threshold, the downshift differential value determination threshold, and the downshift integral value determination threshold described above are corrected according to the road surface μ estimated by the road surface μ estimation device 40. For example, when the road surface μ is low, Alternatively, each threshold value may be increased to make it difficult to make the downshift determination, and tire locking due to an increase in the engine brake braking force may be prevented.

<Step S10: Shift hold>
The shift control means 39 decides to hold (shift hold) the current shift stage without downshifting, and ends (returns) a series of processes.

<Step S11: Downshift execution>
The shift control means 39 determines to perform a downshift, controls the solenoid valve 25 of the automatic transmission 20, and causes the transmission mechanism unit 22 to execute the downshift.
Thereafter, the series of processing is terminated (returned).

Next, the effect by Example 1 mentioned above is demonstrated in detail.
FIG. 4 is a graph showing two examples of transitions of the shift determination value Cs in the shift control apparatus of the first embodiment. In FIG. 4, the horizontal axis represents time, and the vertical axis represents the shift determination value Cs. (Same in FIGS. 6 and 8)
In the data D1 shown in FIG. 4, after starting braking, the shift determination value Cs gradually increases mainly due to an increase in the deceleration G, reaches a peak value, and then gradually decreases to finally become zero. In this data D1, since the shift determination value Cs exceeds the downshift determination threshold, the downshift control is performed at the control operation point T1 shown in the figure.

On the other hand, in the data D2, the shift determination value Cs rises earlier than the data D1, then changes at a substantially constant value lower than the downshift determination threshold, and then decreases.
Here, the area of the hatched portion of data D1 (lower right hatch) and the hatched portion of data D2 (left downward hatch), that is, the deceleration amount from the start to the end of braking are substantially the same.
In the case of data D2, even if the total amount of deceleration during the braking period is equal to or greater than that of data D1, the shift determination value Cs is determined to be a downshift unless a downshift determination is made under other conditions. Since the threshold value is not exceeded, the downshift is not performed, and the driver perceives the control unevenness.

FIG. 5 is a graph showing the transition of the shift determination value differential value ΔCs in the case of FIG. In FIG. 5, the horizontal axis indicates time, and the vertical axis indicates the shift determination value differential value ΔCs. (Same in FIG. 7)
In the data D2, as described above, the shift determination value Cs does not exceed the downshift determination threshold. However, in the case of the differential value ΔCs, the shift determination value Cs at the beginning of braking rises quickly, so the downshift differential value determination The threshold value is exceeded, downshift control is performed at the control operating point T2 shown in the figure, and the occurrence of the above-described control unevenness can be prevented.

FIG. 6 is a graph showing another example of the shift of the shift determination value Cs in the shift control apparatus of the first embodiment. 6 to 8, the data D1 described above is also shown for reference.
In the data D3 shown in FIG. 6, the shift determination value Cs rises with a small increase rate (inclination) with respect to the data D2, and further, the change rate decreases stepwise during the increase. Thereafter, the shift determination value Cs takes a substantially constant value smaller than the downshift determination threshold, and then the shift determination value Cs decreases and finally becomes zero.
Here, the area of the hatched portion of data D1 (lower right hatch) and the hatched portion of data D3 (lower left hatch), that is, the deceleration amount from the start to the end of braking is substantially the same.
In the case of the data D3 as well as the data D2, the shift determination value Cs does not exceed the downshift determination threshold even if the total amount of deceleration during the braking period is equal to or greater than that of the data D1. In the determination using the determination value Cs, the downshift control is not performed.

FIG. 7 is a graph showing the transition of the shift determination value differential value ΔCs in the case of FIG.
In the case of data D3, since the rate of increase of the shift determination value Cs at the initial stage of braking is smaller than that of data D2, the shift determination value differential value ΔCs does not exceed the downshift differential value determination threshold, and the shift determination value differential value Even with the determination using ΔCs, the downshift control is not performed.

FIG. 8 is a graph showing the shift determination value integrated value ICs in the case of FIG.
In the case of the data D3, the shift determination value integrated value ICs (the area of the hatched portion in the figure) in the period T [s] exceeds the predetermined downshift integral value determination threshold. Downshift control is performed at the control operating point T3 shown in FIG.
Thus, even when the determination using the shift determination value Cs and the differential value ΔCs is not established, the downshift control can be executed, and the occurrence of control unevenness can be prevented.

As described above, according to the first embodiment, the following effects can be obtained.
(1) When the differential value ΔCs of the shift determination value Cs calculated based on the vehicle acceleration vector Cvec exceeds the downshift differential value determination threshold, the shift determination value Cs is determined to be downshifted by executing a downshift. Even when the threshold value is not exceeded, for example, when the deceleration G or the like rises quickly, a downshift can be executed, and appropriate shift control can be performed.
(2) When the integrated value ICs of the shift determination value Cs calculated based on the vehicle acceleration vector Cvec exceeds the downshift integrated value determination threshold, the shift determination value Cs is determined to be downshifted by executing a downshift. Even if the threshold value is not exceeded, for example, if the total amount of deceleration within a predetermined period is large, a downshift can be executed and appropriate shift control can be performed.
(3) By correcting the shift determination value Cs so that the downshift determination is difficult to be established according to the increase in the angle θv of the acceleration vector Cvec due to the increase in the lateral acceleration Gy, the lateral acceleration due to cornering is large, and the tire However, when the remaining force of the longitudinal force that can be generated within the range of the friction circle limit value is insufficient, it is possible to suppress the downshift and prevent the tire from slipping.
(4) By calculating the shift determination value Cs based on the vector Cvec obtained by combining the longitudinal acceleration Gx and the lateral acceleration Gy, the shift determination value Cs that can appropriately evaluate the longitudinal force and lateral force of the tire with respect to the friction circle limit value. Can be obtained, and appropriate shift control can be performed.
(5) The shift Cs calculated on the basis of the scalar quantity Ve of the acceleration vector Cvec is corrected so as to decrease as the angle θv of the acceleration vector Cvec increases, so that the above (4) The effect of the term can be obtained.

Next, a second embodiment of the shift control device for an automatic transmission to which the present invention is applied will be described. In addition, about the part substantially common with Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted and a difference is mainly demonstrated.
FIG. 9 is a schematic diagram illustrating a system configuration of the automatic transmission according to the second embodiment.
In the first embodiment described above, the shift determination value Cs is calculated by correcting the scalar quantity Ve of the acceleration vector Cvec according to the angle θv. However, in the second embodiment, instead of this correction, the shift determination value is calculated. The threshold value corresponding to each of the differential value and the integral value is corrected according to the angle θv of the acceleration vector Cvec.

In the second embodiment, the scalar quantity Ve of the acceleration vector Cvec calculated by the vector calculation means 35 is used as the shift determination value Cs. For this reason, in Example 2, the vector calculation means 35 functions as a shift determination value calculation means.
Further, as shown in FIG. 9, the TCU 30 of the second embodiment is provided with a threshold correction means 60.
The threshold correction means 60 is a shift determination value Cs, a shift determination value differential value ΔCs, a shift determination value integration used for downshift determination in the shift control means 39 according to the angle θv of the acceleration vector Cvec calculated by the vector calculation means 35. The threshold value corresponding to each value ICs is corrected. This point will be described in detail later.

FIG. 10 is a flowchart showing the operation of the TCU 30 when performing the braking control.
The flow is different from the flow shown in FIG. 3 of the first embodiment in that step S21 is provided instead of step S04 and that step S22 is provided between step S06 and step S07. . Hereinafter, steps S21 and S22 will be described.

<Step S21: Shift Determination Value Calculation>
The vector calculation means 35 outputs the scalar quantity Ve of the acceleration vector Cvec obtained in step S03 as the shift determination value Cs without correcting it with the angle θv.
Thereafter, the process proceeds to step S05.

<Step S22: Correction of each determination threshold>
The threshold value correction means 60 corrects the downshift determination threshold value, the downshift differential value determination threshold value, and the downshift integral value determination threshold value used in the shift control means 39 according to the angle θv of the acceleration vector Cvec.
Specifically, both the downshift determination threshold value and the downshift differential value determination threshold value are corrected so as to increase as the current angle θv increases.
The downshift integrated value determination threshold value is corrected so that the downshift integrated value determination threshold value also increases when the angle θv increases during the integration period of the shift determination value integrated value ICs to be compared. If the angle θv is greater than or equal to a predetermined value at the time of determination in step S09, the determination is performed using the downshift integrated value determination threshold that has been corrected for increase. On the other hand, if the angle θv at the time of determination in step S09 is less than a predetermined value due to the vehicle passing through a curved road or the like, the determination is performed by returning the downshift integrated value determination threshold value to a predetermined reference value.
Also in the second embodiment described above, substantially the same effect as that of the first embodiment described above can be obtained.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention.
(1) The configurations of the shift control device and the automatic transmission are not limited to the configurations of the embodiments, and can be changed as appropriate. For example, the automatic transmission to be controlled is not limited to the one using the torque converter and the planetary gear set as in the embodiment. For example, AMT in which shifting and selection is performed by an actuator based on a manual transmission base, odd stages, even numbers DCT which switches a gear set of a stage with a plurality of clutches may be used, and the number of stages is not particularly limited.
The automatic transmission may be a continuously variable transmission (CVT) such as a belt type or a toroidal type. In this case, downshift refers to a speed change operation in a direction in which the reduction ratio is increased.
(2) In the embodiment, the acceleration in the front-rear direction and the lateral direction is detected using the acceleration sensor, but the method for obtaining the acceleration is not particularly limited and can be changed as appropriate. For example, the longitudinal acceleration may be obtained based on the change in the vehicle speed sensor output or the brake fluid hydraulic pressure. Further, based on the vehicle running state such as the vehicle speed, the steering angle, and the yaw rate, the lateral acceleration resulting from the turn may be estimated using the vehicle motion model. Further, the vehicle speed sensor is not limited to the one provided in the transmission as in the embodiment, and may be, for example, a sensor that detects the rotation of the wheel hub.
(3) In the embodiment, the engine is, for example, a gasoline engine that performs output control using a throttle valve. However, the present invention is not limited to this, and a so-called valve throttling that performs output control according to valve opening / closing timing and lift amount is used. It can also be used for control of an automatic transmission provided in other engines such as a gasoline engine to be performed or a diesel engine that performs output control with a fuel injection amount.
(4) In the embodiment, one threshold value is set for each of the shift determination value, the differential value, and the integral value. However, for example, two threshold values are set, the shift determination value exceeds the first threshold value, and the second threshold value is set. If the stage threshold is not exceeded, a one-stage downshift may be performed, and if the second stage threshold is exceeded, a two-stage downshift may be performed. Moreover, it is good also as control using the threshold value of three steps or more.
(5) In the embodiment, the shift determination value and each threshold value are corrected based on the angle of the acceleration vector, but may be corrected using lateral acceleration instead of this angle. In this case, the shift determination value may be reduced and the threshold value may be increased in accordance with the increase in lateral acceleration.

DESCRIPTION OF SYMBOLS 10 Engine 11 Air cleaner 12 Air flow meter 13 Intake duct 14 Throttle body 15 Intake manifold 16 Throttle opening sensor 20 Automatic transmission 21 Torque converter 22 Transmission mechanism part 23 Propeller shaft 24 Hydraulic circuit part 25 Solenoid valve 26 Vehicle speed sensor 27 Inhibitor switch 30 Shifting Machine control unit (TCU)
Reference Signs List 31 longitudinal acceleration sensor 32 lateral acceleration sensor 33 longitudinal acceleration computing means 34 lateral acceleration computing means 35 vector computing means 36 shift determination value calculating means 37 shift determination value differentiating means 38 shift determination value integrating means 39 shift control means 40 road surface μ estimating device 50 Road surface gradient detection means 60 Threshold correction means

Claims (6)

A shift control device that performs shift control of an automatic transmission,
Acceleration calculation means for calculating the acceleration of the vehicle;
Shift determination value calculating means for calculating a shift determination value based on the acceleration calculated by the acceleration calculating means;
Shift determination value differentiating means for differentiating the shift determination value calculated by the shift determination value calculating means;
When the differential value of the shift determination value obtained by the shift determination value differentiating unit exceeds a threshold, the automatic transmission is allowed to downshift, and the differential value of the shift determination value is less than the threshold. A shift control device for an automatic transmission, comprising: a shift control means for prohibiting the downshift. A shift control device that performs shift control of an automatic transmission,
Acceleration calculation means for calculating the acceleration of the vehicle;
Shift determination value calculating means for calculating a shift determination value based on the acceleration calculated by the acceleration calculating means;
Shift determination value integration means for integrating the shift determination value calculated by the shift determination value calculation means;
When the integral value of the shift determination value obtained by the shift determination value integration means exceeds a threshold, downshift of the automatic transmission is permitted, and when the integral value of the shift determination value is less than the threshold A shift control device for an automatic transmission, comprising: a shift control means for prohibiting the downshift. The acceleration calculating means includes a longitudinal acceleration calculating means for calculating the longitudinal acceleration of the vehicle, and a lateral acceleration calculating means for calculating the lateral acceleration of the vehicle,
The correction means for correcting at least one of the shift determination value and the threshold value so as to make it difficult to permit the downshift according to an increase in the lateral acceleration. Item 3. A transmission control device for an automatic transmission according to Item 2. The shift determination value calculating means calculates the shift determination value based on a vector obtained by combining the longitudinal acceleration calculated by the longitudinal acceleration calculating means and the lateral acceleration calculated by the lateral acceleration calculating means. The shift control device for an automatic transmission according to claim 3, wherein the shift control device performs calculation. The correction means corrects the shift determination value calculated by the shift determination value calculation means based on the scalar quantity of the vector so that the vector direction decreases as the direction of the vector changes from the front-rear direction to the horizontal direction. The shift control apparatus for an automatic transmission according to claim 4. 5. The shift control device for an automatic transmission according to claim 4, wherein the correction unit corrects the threshold value so as to increase as the direction of the vector changes from the front-rear direction to the horizontal direction.

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