JP2876867B2 - Shift control method for automatic transmission for vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control method for an automatic transmission for a vehicle, and more particularly to a shift control method for cornering a vehicle.

[0002]

2. Description of the Related Art In a conventional automatic transmission for a vehicle, a shift pattern is set in advance in accordance with a throttle opening (engine load) and a vehicle speed, and detection is performed using the shift pattern. The shift speed is set according to the throttle opening and the vehicle speed, and the shift shift is automatically executed. The conventional automatic shift control method has no particular problem in shift shifting on a flat road such as running in a city, and the shift is smooth and has no uncomfortable feeling. However, when traveling in the mountains, there are straight uphill roads and frequent bending uphill roads, and there are some downhill roads that require strong engine braking and some gentle long downhill roads. Some drivers accelerate suddenly on a downhill and perform a strong braking operation just before entering a corner. During such mountain running, it is difficult to select the most appropriate gear position for the vehicle driving condition, driver's driving intention, road condition, etc. There is a demand for better and better driving feeling.

In response to such a request, a so-called "fuzzy control" is performed, and a shift control method for selecting an optimum shift speed according to the above-mentioned vehicle operating condition is disclosed in, for example, Japanese Patent Laid-Open No.
-246546 and JP-A-02-3738. These conventional shift control methods attempt to determine an optimal shift speed by estimating all shift positions in city driving and mountain driving by fuzzy inference. For this reason, the conventional shift control method based on "fuzzy control" has disadvantages such as a large number of rules and a complicated membership function shape, and requires a large-capacity computer for practical use. . Further, since the number of rules is large and the shape of the membership function is complicated, tuning is difficult, and therefore, there is a problem that it is difficult to expand to multiple models.

Further, when a shift control method based on "fuzzy control" is newly adopted, a conventional shift shift does not occur for a driver who is accustomed to running on a normal flat road such as a city running by the conventional automatic shift control method. Under such circumstances, a problem arises in that a shift change is executed due to a small change in the operating state, such as getting over a small protrusion or stepping on a small accelerator, and giving a sense of incongruity.

[0005] On the other hand, in Japanese Patent Application Laid-Open No. 2-212655, various parameters representing the running state of a vehicle are detected, and fuzzy inference is performed based on the detected signal and a preset membership function to determine the magnitude of the running resistance. When the running resistance value is larger than a predetermined value, a shift map for high load running is selected instead of the shift map for normal running, and the shift speed is determined based on the shift map for high load running. A control method has been proposed. However, in this proposed shift control method, the same shift map is used for both straight uphill roads and frequently-upward uphill roads. There is a problem that shift control cannot be performed sufficiently.

Further, when the frictional resistance coefficient μ of the traveling road is small, there is a problem that the vehicle behavior is liable to greatly change due to a slight disturbance or a change in driving force due to a stepping over a small protrusion, a brake operation, a steering wheel operation, or the like. is there. The present invention has been made in view of the above problems, and provides a shift control method for an automatic transmission for a vehicle in which a curve or a corner is stably turned without disturbing the posture of the vehicle body. It is.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, an automatic transmission having a plurality of gear positions is switched from one gear position to another gear position. In the shift control method, a parameter value related to road surface frictional resistance is detected, a steering wheel angle and a lateral acceleration acting on the vehicle are detected to determine whether or not the vehicle is cornering. An automatic transmission for a vehicle, wherein when the frictional resistance of the road surface is determined to be small on the basis of the parameter value to be detected, and when it is detected that the vehicle is cornering, the gear shift is prohibited. Is provided.

Preferably, the road surface is constantly worn when the vehicle is running.
By detecting the parameter value related to the frictional resistance,
The road surface frictional resistance is low based on the
It is preferable to determine whether or not the parameter value related to frictional resistance, which is detected when the vehicle is traveling, is stored, and a parameter value equal to or less than a first predetermined value corresponding to a low μ road is determined. When the sum of the detected frequencies is greater than or equal to the second predetermined value, it is preferable to determine that the road surface frictional resistance is small.
Further, when the sum of the frequencies decreases to a value equal to or less than the second predetermined value, the road surface is maintained until the first predetermined time elapses from the time when the sum of the frequencies crosses the second predetermined value. The determination that the friction resistance is small may be continued .

More preferably, a hydraulic pressure proportional to a steering wheel angle, a vehicle speed, and a cornering force acting on the vehicle at the time of operating the steering wheel is generated, and the hydraulic pressure of a steering device for assisting a steering force is detected. May be used to detect the frictional resistance value of the road surface.

[0010]

When a shift operation is performed during cornering of a vehicle on a road surface state where it is determined that the frictional resistance of the road surface is small, a slight change in the driving force may cause unstable vehicle behavior. In such a case, such inconvenience is avoided by prohibiting the switching of the shift speed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the preferred embodiment of the present invention, the basic concept of the present invention will be described with reference to FIG. Normal mode (MODE0) for road use, uphill corner mode (MODE1) for use on hills that frequently bend in the mountains, and weak engine brakes for downhill use on roads that require weak engine brakes on gentle downhills. Mode (MODE2), downhill strong engine brake mode (MODE3) for use on roads that require strong engine braking on steep downhills or downhills with large degrees of curvature, straight uphill roads for use on long straight uphills Each control mode of the mode (MODE4) is prepared.

In the normal mode 0, a shift pattern for traveling on a flat road in an urban area or the like is prepared in advance, and the shift pattern for traveling on a flat road is used to optimize the shift pattern according to the accelerator opening (engine load) and the vehicle speed. The method of setting the appropriate gear stage is no different from the conventional gear shift control method. When this mode 0 is selected, the shift speed is set by a separately prepared shift control program.

In the uphill corner mode 1, a shift pattern different from the shift pattern for traveling on a flat road is prepared for traveling on an uphill curved road (details will be described later). The shift pattern is set so that a shift-up shift is unlikely to occur, and shift hunting is prevented. In the weak downhill engine brake mode 2 and the downhill strong engine brake mode 3, the third speed and the second speed are forcibly set, respectively, and an appropriate engine brake is automatically applied, and the overhill at a downhill corner is obtained. Prevent speed entry and reduce brake operation.

In the straight uphill mode 4, the gear is set one step lower than the current shift position, and the necessary driving force is secured. In the straight uphill mode 4, since the downshift operation is automatically performed, the necessary driving force is secured and shift hunting is prevented. The shift control in mode 4 is particularly effective for a vehicle with a small displacement. In the shift control method of the present invention, these control modes are fuzzy inference based on various fuzzy input variables representing a vehicle driving state, a driver's driving intention, and a road state, and a membership function (referred to as a crypt set). And selected
The fuzzy shift position is set based on the selected control mode. Therefore, since the shift position is not set by directly estimating all shift positions in city driving and mountain driving by fuzzy inference, the number of rules for selecting the control mode is small and the membership function is simplified. .

The arrows between the control modes shown in FIG. 1 indicate the directions of the control modes that can be switched from the current control mode, which will be described later in detail. For example, if the current mode is the uphill corner mode (MODE1)
In this case, it is possible to return from the mode 1 to the normal mode 0 and directly switch to the downhill weak engine brake mode 2 but not directly to the straight uphill road mode 4. It is not possible to directly switch from the normal mode 0 to the downhill strong engine brake mode of the mode 3, and it must be switched via the mode 2 without fail.

The hardware structure diagram 2 of a shift control device for an automatic transmission, schematically showing a shift control system for an automatic transmission to which the present invention method is applied, an internal combustion engine (E mounted on a vehicle
A gear transmission (T / M) 3 is connected to the output side of / G) 1 via a torque converter 2. This transmission 3
Has, for example, four forward speeds and one reverse speed, and a desired speed can be established by engaging or disengaging a brake or clutch (not shown). The shift control device includes an operating oil pressure control device 4, and controls an operating oil pressure supplied to the above-described brake and clutch in response to a control signal from an electronic control unit (ECU) 5 described later. The transmission and the hydraulic control device to which the method of the present invention is applied may be of various types, such as hydraulic control for a shift shift, and are not particularly limited.

The electronic control unit 5 sets an optimum gear position according to a vehicle driving state or the like, and outputs a control signal corresponding to the gear position set in the operating hydraulic pressure control device 4 described above.
The hydraulic control unit 4 is connected to the output side of the electronic control unit 5, and various sensors (not shown) are connected to the input side. These sensors supply the electronic control unit 5 with detection signals relating to the driving intention of the driver, the operating state of the vehicle including the engine 1, and the road conditions.

These input signals (input variables) include:
The accelerator pedal depression amount of the driver detected by the accelerator position sensor 10, that is, the accelerator position (opening) APS, the shift position of the shift lever SPOS detected by the shift position sensor 12, and the OD switch 14 for selecting the fourth speed ON / OFF signal OD, the ON / OFF signal BRK of the brake switch 16 which is turned ON / OFF by the driver's depression of the brake pedal, the wheel speed sensor 1
8, the wheel speed signal for calculating the vehicle speed V0 and the longitudinal acceleration Gx acting on the vehicle, the engine speed signal Ne of the engine 1 detected by the engine speed sensor 20, and the intake air amount sensor 22 detect. An intake air amount signal A / per intake stroke of the engine 1 calculated from the air flow rate per unit time and the engine speed Ne.
N, a torque converter speed ratio (slip ratio) e calculated from the turbine speed of the torque converter 2 and the engine speed Ne detected by the turbine speed sensor 24, and output from the electronic control unit 5 to the working hydraulic control unit 4. Commanded shift speed signal SHIF0, a calculated shift speed signal SHIF1 on the map determined from the shift pattern of mode 0, a steering wheel angle signal θw detected by the steering wheel angle sensor 28 and indicating a steering wheel operation amount of the driver, a power steering. The power steering pressure signal PST and the like detected by the pressure sensor 28 and obtained as a pressure difference between left and right pressure chambers (not shown) of the front wheel steering actuator are included.

The information from the various sensors described above may be detected by a sensor specially provided for speed change control. Fuel supply control for injecting a required amount of fuel, antilock braking control during braking (AB
S control), traction control for controlling the output of the engine 1 and the like are also necessary, so that necessary information may be obtained from these control devices.

The electronic control unit 5 includes input / output devices 5A and 5
B, storage device 5C, central processing unit (CPU) 5D,
The input device 5A receives detection signals from the above-described various sensors and performs filtering, amplification, A / D conversion, and the like, while the output device 5B is operated by a central processing unit 5D. Based on the result, the control signal is output to the hydraulic control device 4.
The storage device 5C is composed of a non-volatile RAM that is backed up by a battery and that retains its stored contents even when a key switch (not shown) is turned off, in addition to a normal RAM or ROM. The central processing unit 5D includes a storage device 5
A control mode is determined by judging a vehicle driving state, a driver's driving intention, a road state, and the like according to a shift control program stored in C, and a gear to be established is calculated based on the determined control mode. The details will be described later.

The gear change control program then calculates the fuzzy shift position in the above-mentioned shift control device, a procedure for performing fuzzy shift control based on the calculation results will be described with reference to a flowchart shown in Figure 3 below. When the normal mode 0 is selected by the fuzzy shift control, the shift control in the normal mode 0 is executed by a separately prepared normal mode shift control program.

The main routine will be described first from the main routine (general flow) of the fuzzy shift control program shown in FIG. This program includes an initial processing routine for setting control variable values and various stored values to initial values, a routine for inputting and calculating input variables from various sensors and the like, and calculating fuzzy input variables from input or calculated input variables. routine,
A routine for setting various fuzzy input switch values from input variables, a routine for determining whether or not a fuzzy rule has been established, a fuzzy shift position prepared according to the currently executed control mode and based on the established fuzzy rule And a routine for outputting the shift position based on the set fuzzy shift position and the like.

The initial processing routine is executed only once at the first execution of the main program, for example, once immediately after an ignition key switch (not shown) is turned on. When the execution of the initial processing routine is completed, the subsequent routines are repeatedly executed at a predetermined cycle (for example, 50 msec).

Input Variable Input / Calculation Routine This routine inputs the input variables necessary for the shift control from the various sensors or the fuel control device described above. Some input variables only require filtering or A / D conversion of the detection signal directly input from the sensor, while others may be obtained by calculation from another input variable input.
In addition, upper and lower limits are provided for the input variable values as needed, and those exceeding the upper and lower limits are limited to the upper and lower limits. Table 1 shows input variables required for the shift control.

[0025]

[Table 1] The vehicle speed V0 is calculated from the wheel speed detected by the wheel speed sensor 18 when a few of the input variables shown in Table 1 are described below. In the case of the shift control, since it is almost unnecessary to consider the slip amount of each wheel, the vehicle speed V0 is
The calculation may be performed from the average value of the wheel speeds of the respective wheels, or may be performed from one of the wheel speeds of the respective wheels. Further, instead of calculating from the wheel speed, the calculation may be performed from the rotation speed of the output shaft of the transmission. The longitudinal acceleration Gx is obtained by calculating from the time change of the vehicle speed V0. This longitudinal acceleration Gx
Since the detection accuracy greatly affects the calculation accuracy of the weight / gradient resistance value described later, it is necessary to remove the noise by performing sufficient filtering.

The steering wheel angle θw is set to the upper limit when the absolute value exceeds a predetermined upper limit (for example, 360 °), and to 0 ° when the absolute value is equal to or smaller than the lower limit (for example, 10 °). Is done. The lateral acceleration Gy is regulated to a value of 0 when the vehicle speed V0 is equal to or less than a predetermined value (for example, 10 km / hr), and to an upper limit when the vehicle speed exceeds a predetermined upper limit. Lateral acceleration G
y is calculated based on the following equation (A1).

[0027] Gy = (θw / ρ) / {Lw · (A + 1 / V0 2)} × C1 ... (A1) Here, [rho handle equivalent gear ratio, Lw is wheelbase (m), A is a stability factor , C1 are constants. In this embodiment, the lateral acceleration Gy is calculated based on the vehicle speed V0 and the steering wheel angle θw according to the above equation (A1). However, an acceleration sensor may be attached to the vehicle body and directly detected by this sensor.

The engine torque ETRQ is read from a torque map preset according to the engine speed Ne and the intake air amount A / N, for example, using a known interpolation method. At this time, the maximum generated torque MXETRQ obtained by changing the intake air amount A / N for the same engine speed Ne from the torque map is also obtained and recorded at the same time.

Calculation of Fuzzy Input Variables Next, 11 fuzzy input variables FV (0) to FV (10) required for fuzzy inference shown in Table 2 are calculated. These fuzzy input variables FV (0) to FV (10) are:
As shown in Table 2, the information is classified into driver's driving intention information, vehicle operation state information, and road information. Although the steering wheel angle information of the road information is also the driver's driving intention information, the degree of bending of the road is determined from the steering wheel angle information and is treated as road information. Although the lateral acceleration information of the road information is also vehicle operation information, the degree of curvature of the road can be determined from this information and is treated as road information.

[0030]

[Table 2] Of the fuzzy input variables shown in Table 2, the steering wheel operation amount FV
(2) is the effective value of the product of the steering wheel angle and the lateral acceleration Gy.
And the average value of the effective values in the past predetermined period (for example, 20 seconds) is used as a parameter indicating the busyness of the steering wheel operation. The procedure for calculating the handle operation amount will be described with reference to FIG.

First, the program control variable N1 is incremented by 1 (step S10). Then, it is determined whether or not the variable value N1 has reached a predetermined value (20) corresponding to a predetermined time (for example, 1 second) (step S1).
2) Steps S10 and S12 are repeatedly executed until a predetermined value is reached. When the variable value N1 reaches a predetermined value, the variable value N1 is returned to 0 (step S1).
4), execute step S16. That is, step S16 is executed every predetermined time (1 second).

In step S16, the steering wheel operation amount FV (2) is calculated by the following equations (A2) and (A3).

[0033]

(Equation 1) The above equations (A2) and (A3) are actually calculated for a predetermined time (1 second)
The product of each square value of the steering angle θw and the lateral acceleration Gy detected for each is sequentially stored in a ring buffer for storing 20 data, and is sequentially deleted to obtain an average value of the stored data. By calculating the square root, the effective value of the product of the steering wheel angle and the lateral acceleration Gy can be easily obtained.

The steering wheel operation amount FV (2) is determined by considering both the steering wheel angle and the lateral acceleration factor.
When turning at the same corner, the higher the vehicle speed, the larger the value. At the same vehicle speed, the smaller the radius of the corner R, the larger the value. When the steering wheel angle is the same, the lateral acceleration increases as the vehicle speed increases, and the steering operation amount FV (2)
Is a large value. Thus, the steering operation amount FV
(2) can be regarded as an index including the frequency of steering operation and the degree of driver's tension.

Comparing the steering wheel operation amount FV (2) obtained from 20 samples per second with the values obtained when the vehicle is traveling on a standard city, traveling on a medium-speed curved road, and traveling on a meandering curved road, it is found that The average value during traveling is 3.0 (g
Deg), when the vehicle is traveling on a meandering curved road, it is 40 g / deg or more. Since there is a remarkable difference in the steering wheel operation amount FV (2) when traveling on these roads, it is determined that the vehicle is traveling on these roads. can do.

For example, in an urban area, for example, even if a vehicle gets over a protrusion and a rule for discriminating an uphill road or a downhill road is established by another fuzzy input variable, the steering wheel operation amount FV (2) is set to the above value. If it is 3.0 (g · deg) or less, it can be reliably determined that the vehicle is traveling in an urban area.
The brake deceleration width FV (3), which is the fourth fuzzy input variable in Table 2, indicates the vehicle speed V0 by how many km / km by one braking operation.
It indicates whether hr has been dropped. Immediately after the brake switch is turned off, there is a possibility that the calculation of the brake deceleration width FV (3) cannot be accurately performed because, for example, it takes time to release the frictional engagement between the brake shoe of the brake device and the caliper. Therefore, immediately after the end of braking, the brake deceleration width FV
The calculation of (3) is prohibited for a predetermined time (for example, 0.3 seconds). The flowchart of FIG. 5 shows a procedure for calculating the brake deceleration width and prohibiting the calculation after the brake switch is turned off.

First, the electronic control unit 5 determines whether or not the brake switch BRK has a value of 1 (step S2).
0). The BRK value is 1 when the driver steps on the brake petal to perform a braking operation, and the BRK value is 0 when the driver releases his / her foot from the brake petal. If the driver does not perform any braking operation, the determination result of step S20 is negative (No), and in this case, step S2 described later will be performed.
After the determination of 2, the process proceeds to step S24, and the vehicle speed V0 detected this time is stored as a variable value VST. The variable value VST is updated every time the braking operation is not performed, and the vehicle speed immediately before the braking is stored by the variable VST.

When the driver steps on the brake pedal, the result of the determination in step S20 becomes affirmative (Yes), and the routine proceeds to step S26, where the timer flag BFLG is set to a predetermined value XB.
(For example, a value corresponding to 0.3 seconds) is set, and the brake deceleration width FV (3) is calculated by the following equation (A4). The timer flag BFLG is a timer for measuring a predetermined time after the brake switch is turned off.

FV (3) = VST−FV (0) (A4) where VST is the vehicle speed stored immediately before the start of the braking operation, and FV (0) is a fuzzy input variable of the vehicle speed calculated this time. Value. Therefore, as long as the braking operation continues, step S26 is repeatedly executed, and the brake deceleration width FV (3) decelerated by the braking operation is updated. In the calculation in step S26, if VST <FV (0), the value 0 is set to the brake deceleration width FV (3).

When the driver releases his / her foot from the brake petal,
Again, the result of the determination in step S20 is negative, and in step S22, it is determined whether or not the timer flag BFLG is greater than zero. Immediately after the driver releases his / her foot from the brake pedal, the BFLG value is set to the predetermined value XB, so the determination in step S22 is affirmative, and the process proceeds to step S28 to decrement the flag value BFLG by one. At the same time, the brake deceleration width FV (3) is reset to 0. Then, until the flag value BFLG is subtracted toward the value 1 to become the value 0, that is, a predetermined time (0.3 seconds)
Step S28 is repeatedly executed until
During this time, the calculation of the brake deceleration width FV (3) is prohibited by setting the value to 0.

When the predetermined time (0.3 seconds) has elapsed, the result of the determination in step S22 is negative, and the aforementioned step S2
4 is executed, and the updating of the variable value VST is repeated. The accelerator depression speed FV (5) is an accelerator opening FV (4) detected every predetermined time (for example, 0.25 seconds).
Is obtained by converting the difference into a difference for one second. In this embodiment, the accelerator depression speed FV (5) is obtained by quadrupling the difference obtained every 0.25 seconds. The flowchart shown in FIG. 6 shows a procedure for obtaining the accelerator depression speed FV (5). First, the electronic control unit 5 increments the program variable N2 by the value 1 in step S30. The program variable N2 is used as an up counter, and after incrementing, the variable value N2 is determined (step S32), and every time the variable value N2 reaches a predetermined value XN2 (a value corresponding to 0.25 seconds), a step is performed. S34 and step S36 are executed.

In step S34, the program variable value N
2 is reset to a value of 0, and in step S36, the accelerator depression speed FV (5) is calculated by the method described above. That is, first, the amount of change in the accelerator opening that has changed in 0.25 seconds is calculated by the following equation (A5). FV (5) = FV (4) −APSO (A5) where FV (4) is the accelerator opening A detected this time.
This value is set as it is using PS.
The variable APSO is an accelerator opening detected 0.25 seconds before, as described later. Next, 0.
4 times the amount of change in the accelerator opening that changed over 25 seconds
It is converted to the amount of change per second, and this is used as the accelerator depression speed FV
Reset as (5).

FV (5) = FV (5) × 4 (A6) Next, the accelerator opening FV (4) which is a fuzzy input variable set this time is updated and stored as a variable value APSO. APSO = FV (4) (A7) This stored value APSO is used for calculating the change amount of the accelerator opening after 0.25 seconds.

Next, a method of calculating the weight / gradient resistance FV (6) which is a fuzzy input variable shown in Table 2 will be described with reference to FIG. First, the electronic control unit 5 determines the vehicle speed FV (0)
Is determined to be less than or equal to a predetermined value CFV0 (for example, 10 km / hr) (step S40). If the vehicle speed FV (0) is less than or equal to the predetermined value CFV0, the weight / gradient resistance FV (6) is set to a value of 0. Is set to 0.0 in the current calculated value XR of the weight / gradient resistance (step S41), and the process proceeds to step S46 described later.

In step S40, the vehicle speed FV (0)
Is larger than the predetermined value CFV0, the process proceeds to step S42, and it is determined whether or not a predetermined time (0.3 seconds) has elapsed during braking and from the end of the braking. This determination is based on whether the timer flag BFLG used in the above-described routine for calculating the brake deceleration width FV (3) is also used in this routine, and whether or not the timer flag BFLG is greater than zero. As described above, the timer flag BFLG is always reset to the initial value XB (a value corresponding to 0.3 seconds) during braking, and the value of the timer flag BFLG becomes 1 (until a predetermined time elapses) from the time when the braking ends. It is decremented. If the determination result in step S42 is affirmative, that is, if the predetermined time (0.3 seconds) has not elapsed yet during braking or the braking end point, the weight / gradient resistance FV (6) cannot be calculated. Therefore, in this case, the previous value is held as the current calculated value XR and the value is used (step S
43). On the other hand, if braking is not being performed and a predetermined time has elapsed after braking, step S44
To calculate the current calculated value XR of the weight / gradient resistance FV (6) as follows.

The weight / gradient resistance is obtained by subtracting the aerodynamic resistance, the rolling resistance and the acceleration resistance from the engine driving force, and is represented by the following equation (A8). XR = engine driving force−aerodynamic resistance−rolling resistance−acceleration resistance (A8) As described above, the weight / gradient resistance cannot be determined during braking or the like, but the rolling resistance during vehicle turning. By including the resistance due to the cornering force, the calculation can be performed accurately. The above formula (A
The engine driving force in 8) is calculated by the following equation (A9). Engine driving force = T _E (η _E ) · t (e) · η · i _T · i _F / r (A9) Here, T _E (η _E ) is the engine torque after the exhaust loss has been subtracted ( kg · m), and t (e) is the torque ratio of the torque converter 2 and is read from a torque ratio table stored in advance as a function of the torque converter speed ratio e. η is the transmission efficiency of the transmission 3 and i _F is the differential gear ratio, and these values are given as constants. i _T is a gear ratio of the transmission 3, and a predetermined gear ratio corresponding to a commanded shift speed SHIF0 as an input variable is used. r is the moving radius (m) of the tire, and a predetermined value is used.

The aerodynamic resistance in the equation (A8) is calculated by the following equation (A10). The aerodynamic drag = ρa · S · Cd · V0 2/2 = C2 · V0 2 ... (A10) where, .rho.a is air density, the outside air temperature is given by a constant when constant. S is a vehicle front projected area, Cd is a drag coefficient, and these values are also constants. Therefore, the aerodynamic resistance can be calculated as a function of only the vehicle speed V0, assuming that C2 is a constant, as in equation (A10).

The rolling resistance in the equation (A8) is calculated by the following equation (A11). Rolling resistance ^{= R0 + (CF 2 / CP} ) ... (A11) here, R0 is the rolling resistance at the time of free-rolling, CF is cornering force, CP is a cornering power. The second term on the right side of the above equation is a contribution term due to cornering resistance when the sideslip angle is small. The rolling resistance R0 during free rolling is calculated by the following equation (A12).

R 0 = μr · W (A12) where μr is a rolling resistance coefficient, and W is a vehicle weight. Keep the load sharing ratio between the front and rear wheels constant (for example,
6: 0.4), assuming the cornering power of the front and rear wheels to be CPf and CPr (constant values), respectively, and considering the two-wheel model, the cornering resistance of equation (A11) should be calculated by the following equation (A13). Can be.

[0050]

(Equation 2) Here, C3 is a constant. As described above, since the cornering resistance is included in the rolling resistance, the weight / gradient resistance when the steering wheel is largely turned can be accurately calculated. That is, when the cornering resistance is not included, the gradient during the cornering is calculated to be smaller than the actual slope on the down-curved road, and it may be estimated that the vehicle is going uphill when turning even on a flat road, and by including the cornering resistance, These are eliminated.

The acceleration resistance in the equation (A8) is calculated by the following equation (A14). Acceleration resistance = (W + ΔW) · Gx (A14) Here, W is the above-mentioned vehicle weight, and ΔW is the weight equivalent to the rotating portion. Then, the weight ΔW corresponding to the rotating portion is calculated by the following equation (A15). ΔW = W0 × {Ec + Fc (i T · i F) 2} ... (A15) here, W0 is unladen weight, Ec tire rotational portions corresponding weight percentage, Fc is the engine rotational portion corresponding weight ratio,
i _T and i _F are the gear ratio of the transmission 3 and the differential gear ratio described above.

When the computation of the computed value XR is completed as described above, the computed value XR is subjected to digital filter processing to remove noise (step S46), and this is used as a fuzzy input variable FV (6). It is stored (step S48). The engine torque margin FV (7), which is a fuzzy input variable shown in Table 2, is calculated based on the following equation (A16).

FV (7) = MXETRQ−ETRQ (A16) Here, MXETRQ and ETRQ are the engine torque and the maximum engine torque read from the torque map in the input variable input / calculation routine.
Next, a method of calculating the two-second difference FV (8) of the vehicle speed, which is a fuzzy input variable shown in Table 2, will be described with reference to FIG.
It is preferable to store the detected vehicle speed data in a ring buffer every time the vehicle speed is detected in the control cycle (50 msec), and to calculate a two-second difference FV (8) of the vehicle speed each time the vehicle speed is detected. If you have a limited amount of storage,
For example, the difference may be obtained every 0.25 seconds. In the flowchart shown in FIG. 8, a two-second difference FV (8) of the vehicle speed is obtained every 0.25 seconds.

The electronic control unit 5 starts with step S50.
In the above, the program control variable K1 is incremented by the value 1 and this variable value K1 is set to a predetermined value XK1 (for example, 0.25
(A value corresponding to second) is determined (step S52). The program control variable K1 is an up-counter for counting a predetermined time (a period of 0.25 seconds in this embodiment). Steps S50 and S52 are repeatedly executed until the predetermined value XK1 is reached. Wait for).

When the variable value K1 reaches the predetermined value XK1, step S54 is executed, and the variable value K1 is reset to zero. Then, after storing the currently detected vehicle speed V0 in a ring buffer (not shown) in step S56, the latest vehicle speed data and the vehicle speed data two seconds ago are taken out from the ring buffer, and a two-second difference FV (8) of the vehicle speed is obtained. Is obtained (step S58).

FV (8) = V0 _n −V0 _n−7 (A17) where V0 _n and V0 _n−7 are the current time and 2
This is the vehicle speed detected two seconds ago. Therefore, the same value of the two-second difference FV (8) of the vehicle speed is maintained for a predetermined time (0.25 seconds). Calculation of Fuzzy Input Switches Fuzzy input switches SW (0) to SW (10) are used to calculate the degree of fitness in the same manner as the membership function of the fuzzy input variable when judging the fuzzy rules.
Since it is represented by a digital value, it is separated from a fuzzy input variable as a switch input. Table 3 shows these fuzzy input switches.

[0057]

[Table 3] The fuzzy input switch SW (0) indicates the selected control mode, and its value is set in each mode process described later.

The fuzzy input switch SW (1) is in a state where the weight / gradient resistance is equal to or higher than a predetermined value CFV61 in a first predetermined period (an appropriate value between 4 seconds and 10 seconds, for example, 5 seconds). For a predetermined time (appropriate value between 2 and 5 seconds, for example, 2.5 seconds), it is determined that the vehicle is climbing the uphill, and the value 1 is set to the switch SW (1). Then, the state of the large gradient resistance is stored.
The above-described first and second predetermined periods are appropriately set experimentally for each vehicle.

Next, the fuzzy input switch value SW
The setting procedure (1) will be described with reference to FIG. First, in step S60, the electronic control unit 5 determines whether or not the weight / gradient resistance value FV (6) is smaller than a predetermined value CFV61 corresponding to a predetermined degree of gradient of the road. If the determination result of step S60 is affirmative, that is, if the gradient of the road is small, the 2.5-second counter CNTSW1 is set to a value of 0.
(Step S61), and the process proceeds to step S64. If the vehicle is continuously traveling on a road with a small gradient, a 5-second counter CN described later is used in this step S64.
After confirming that T5S is equal to or less than 0, step S
Proceeding to 65, the value 0 is set to the fuzzy input switch SW (1) and the routine ends.

When the weight / gradient resistance value FV (6) is a predetermined value CF
If it is determined that the vehicle is traveling on an uphill road with a large gradient at V61 or higher, the 2.5-second counter C is determined in step S62.
After incrementing the value of NTSW1 by 1, it is determined whether or not the counter value CNTSW1 has reached a predetermined value XCN1 (a value corresponding to 2.5 seconds) or more (step S6).
3). If the counter value CNTSW1 is smaller than the predetermined value XCN1, that is, if the predetermined time (2.5 seconds) has not elapsed,
In step S64, it is determined whether the 5-second counter CNT5S is greater than 0. This 5 second counter CNT
5S is a down counter for counting the elapse of a predetermined period (for example, 5 seconds). If the determination in step S64 is affirmative, that is, if the predetermined period (5 seconds) has not elapsed, a 5-second counter CNT5S is set in step S66. Is decremented by 1 and the routine ends. If the weight / gradient resistance value FV (6) continuously exceeds the predetermined value CFV61 within the predetermined period (5 seconds), the 2.5-second counter CNTS
W1 is sequentially incremented, but for a predetermined time (2.5
If the weight / gradient resistance value FV (6) does not continuously exceed the predetermined value CFV61 over the second) and becomes smaller than the predetermined value CFV61 on the way, the 2.5-second counter CNTSW1 is reset (step S61). Second counter CNT5S
Is continuously decremented (step S66).

The weight / gradient resistance value F within a predetermined period (5 seconds)
When the state where V (6) is continuously equal to or more than the predetermined value CFV61 continues for a predetermined time (2.5 seconds), step S63 is performed.
Is affirmative, and step S67 is executed. In this step, the 2.5 second counter CNTSW
1 is the initial value 0, 5 seconds counter CNT5S is the initial value XC
At the same time, the value is reset to N2 (a value corresponding to 5 seconds), the value 1 is set to the fuzzy input switch SW (1), and the routine ends. Fuzzy input switch S
By setting W (1) to a value of 1, the state in which the vehicle is climbing an uphill road with a large gradient resistance is stored. As described above, during the first predetermined period (5 seconds), it is determined that the large gradient resistance state has continued for the second predetermined period (2.5 seconds). Not only can it be detected that the vehicle is climbing, but also, for example, in the case of turning a hairpin curve from a flat road and climbing a steep slope immediately thereafter, the vehicle climbing state can be accurately determined.

The fuzzy input switch SW (2) switches the vehicle downhill when the state where the weight / gradient resistance is larger than the negative predetermined value (-CFV62) continues for a predetermined time (for example, 2.5 seconds). Is determined to have returned from the running state of
A value 1 is set to the switch SW (2) to store the non-negative state of the gradient resistance. This fuzzy input switch value S
The procedure for setting W (2) will be described with reference to FIG.

The electronic control unit 5 starts with step S70
It is determined whether or not the weight / gradient resistance value FV (6) is smaller than a negative predetermined value (-CFV62) corresponding to a predetermined gradient degree of the road. If the determination result in step S70 is affirmative, that is, if the road gradient is still negative, the process proceeds to step S72, in which the 2.5-second counter CNTSW2 is reset to 0 and the fuzzy input switch SW
The value 0 is set in (2), and the routine ends.

On the other hand, if it is determined that the weight / gradient resistance value FV (6) is equal to or more than the negative predetermined value (-CFV62) and the gradient is not negative (non-negative), the value of the 2.5-second counter CNTSW2 is incremented by 1 in step S74. After doing
It is determined whether or not the counter value CNTSW2 has reached a predetermined value XCN3 (a value corresponding to 2.5 seconds) or more (step S76). The counter value CNTSW2 is equal to the predetermined value XCN3.
If it is smaller, that is, if the predetermined time (2.5 seconds) has not elapsed, the routine ends without doing anything. In step S70, if the weight / gradient resistance value FV (6) is equal to or more than the negative predetermined value (-CFV62), it is determined that the gradient is in a non-negative state, and the counter value C is determined in step S76.
If it is determined that the NTSW2 has reached the predetermined value XCN3, a step S78 is executed and a 2.5 second counter CNT is executed.
SW2 is reset to the initial value 0, and the value 1 is set to the fuzzy input switch SW (2), and the routine ends. By setting the value 1 to the fuzzy input switch SW (2), it is stored that the vehicle has returned to the traveling road in the non-negative state of the slope resistance.

The fuzzy input switch SW (3) turns off the vehicle from the uphill running state when the weight / gradient resistance is less than the predetermined value (CFV63) for a predetermined time (for example, 5 seconds). Switch SW
The value 1 is set in (3) to store the non-large gradient resistance state. Below, this fuzzy input switch value SW
The setting procedure of (3) will be described with reference to FIG.

First, the electronic control unit 5 executes step S80.
It is determined whether or not the weight / gradient resistance value FV (6) is larger than a predetermined value (CFV63) corresponding to a predetermined gradient degree of the road. If the determination result in step S80 is affirmative, that is, if the road gradient is still large, the process proceeds to step S82, where the 5-second counter CNTSW3 is set to a value of 0.
And the fuzzy input switch SW
The value 0 is set in (3) and the routine ends.

On the other hand, if the weight / gradient resistance value FV (6) is equal to or less than the predetermined value (CFV63) and it is determined that the state where the gradient is large has been escaped, that is, if the state is determined to be the non-large state, 5 is determined in step S84. The value of the second counter CNTSW3 is 1
After incrementing the counter value CNTSW
It is determined whether or not 3 has reached a predetermined value XCN4 (a value corresponding to 5 seconds) or more (step S86). Counter value C
If the NTSW3 is smaller than the predetermined value XCN4, that is, if the predetermined time (5 seconds) has not elapsed, the routine ends without doing anything.

In step S80, it is determined that the weight / gradient resistance value FV (6) is equal to or less than the predetermined value (CFV63), the gradient is not large, and the counter value CNTSW is set.
If it is determined that 3 has reached the predetermined value XCN4, step S88 is executed, the 5-second counter CNTSW3 is reset to the initial value 0, and the value 1 is set to the fuzzy input switch SW (3), and the routine proceeds to step S88. To end. By setting the value 1 to the fuzzy input switch SW (3), the fact that the vehicle has returned to the traveling road in which the grade resistance is not large (the end of the climb grade) is stored.

The fuzzy input switch SW (4) turns on when the steering operation amount FV (2) is equal to or more than a predetermined value (CFV21) for a predetermined time (for example, 5 seconds).
It is determined that the vehicle is traveling on a zigzag road, the value 1 is set to the switch SW (4), and this state is stored. When it is determined that the vehicle has deviated from the meandering road, the steering wheel operation amount FV is determined using a predetermined value (CFV22) smaller than the predetermined value (CFV21).
It is determined that (2) has become smaller. That is, the determination whether or not the road is a meandering road has a hysteresis characteristic. The procedure for setting the fuzzy input switch value SW (4) will be described below with reference to FIGS.

First, the electronic control unit 5 executes step S90.
It is determined whether or not the value of the fuzzy input switch SW (4) is "0". This fuzzy input switch SW
If the value 0 is set in (4), step S91
If the value 1 is set, step S in FIG.
Go to 96. Fuzzy input switch value SW (4) is 0
If the result of the determination in step S90 is affirmative, the electronic control unit 5 executes step S91 and sets the steering operation amount FV (2) to a predetermined value (CFV21) indicating that the steering operation amount is large. It is determined whether it is smaller.
If the determination result in step S91 is affirmative, that is, if the handle operation amount is not large, the process proceeds to step S92,
The value of the 5-second counter CNTSW4 is reset to 0, and the routine ends.

On the other hand, when it is determined that the steering operation amount FV (2) is equal to or larger than the predetermined value (CFV21) and the steering operation amount is large, the 5-second counter CNT is determined in step S93.
After incrementing SW4 by 1, the counter value CNTSW4 becomes a predetermined value XCN5 (a value corresponding to 5 seconds).
Is determined (step S94). If the counter value CNTSW4 is smaller than the predetermined value XCN5, that is, if the predetermined time (5 seconds) has not elapsed, the routine ends without doing anything.

In step S91, it is determined that the steering operation amount FV (2) is equal to or larger than the predetermined value (CFV21), the steering operation amount is large, and the counter value CNTS
If it is determined that W4 has reached the predetermined value XCN5, step S95 is executed, the 5-second counter CNTSW4 is reset to the initial value 0, and the value 1 is set to the fuzzy input switch SW (4), and this routine is executed. To end. By setting the value 1 to the fuzzy input switch SW (4), the fact that the vehicle is running on a meandering road is stored.

When the value of the fuzzy input switch SW (4) is set to 1, the result of the determination in step S90 is negative, and in this case, the electronic control unit 5 executes step S96 in FIG. In step S96, it is determined whether or not the handle operation amount FV (2) is larger than a predetermined value (CFV22) set to a value smaller than the above-mentioned predetermined value (CFV21). If the determination result in the step S96 is affirmative, that is, it is determined that the vehicle is still traveling on the meandering road, the process proceeds to the step S97, the 5-second counter CNTSW4 is reset to 0, and the routine ends.

On the other hand, if it is determined that the handle operation amount FV (2) is smaller than the predetermined value (CFV22) and the handle operation amount is small, the 5-second counter CNTSW4 is incremented by 1 in step S98. It is determined whether or not the counter value CNTSW4 has reached a predetermined value XCN5 (a value corresponding to 5 seconds) (step S9).
9). If the counter value CNTSW4 is smaller than the predetermined value XCN5, that is, if the predetermined time (5 seconds) has not elapsed,
The routine ends without doing anything.

In step S96, it is determined that the steering operation amount FV (2) is smaller than the predetermined value (CFV21) and the steering operation amount is small, and in step S99, the counter value CNTSW4 has reached the predetermined value XCN5. Is determined, step S100 is executed, and
The 5-second counter CNTSW4 is reset to the initial value 0, and the value 0 is set to the fuzzy input switch SW (4), and the routine ends. By setting the value 0 to the fuzzy input switch SW (4), it is stored that the vehicle has missed out of the road.

The fuzzy input switch SW (5) is set so that the accelerator opening FV (4) has a predetermined value CFV41 (for example, 25).
%) For a predetermined time (for example, 0.6 seconds), the accelerator opening is determined to be large, and the value of the switch SW (5) is set to 1 to set the accelerator opening large. Is stored. The procedure for setting the fuzzy input switch value SW (5) will be described below with reference to FIG.

The electronic control unit 5 starts with step S10
1, the accelerator opening FV (4) is set to a predetermined value (CFV4
1) It is determined whether or not it is smaller. Step S101
Is affirmative, that is, if the accelerator opening is smaller than the predetermined value (CFV41), step S10
Then, the process goes to 2 to reset the counter CNTSW5 to a value of 0, and to set the values of the fuzzy input switch SW (5) and the fuzzy input switch SW (7) to 0, respectively, and terminate the routine. Fuzzy input switch SW
(7) is an accelerator high flag at the time of the third-speed engine braking, and the fuzzy input switch S is described in detail later.
Immediately after W (5) is set to the value 1 in this routine,
When the accelerator opening FV (4) is equal to or larger than the predetermined opening CFV43 (for example, 40%), the value is set to 1 (routine in FIG. 26), and the driver intends to accelerate strongly on a downhill. Is stored.

On the other hand, if it is determined in step S101 that the accelerator opening FV (4) is equal to or larger than the predetermined value (CFV41), the counter CNT is determined in step S104.
After incrementing the value of SW5 by 1, the counter value CNTSW5 becomes a predetermined value XCN6 (a value corresponding to 0.6 seconds).
Is determined (step S106). If the counter value CNTSW5 is smaller than the predetermined value XCN6, that is, if the predetermined time (0.6 seconds) has not elapsed, the routine ends without doing anything.

If it is determined in step S101 that the accelerator opening FV (4) is equal to or more than the predetermined value (CFV41) and the counter value CNTSW5 has reached the predetermined value XCN6, step S108 is executed, and the counter C
NTSW5 is reset to the initial value 0, the value 1 is set to the fuzzy input switch SW (5), and the routine ends. By setting the value 1 to the fuzzy input switch SW (5), the large accelerator opening state is stored.

The fuzzy input switch SW (6) is set so that the accelerator opening FV (4) is set to the predetermined value CFV41 (2).
5%) Predetermined value CFV42 set to a value smaller than
(For example, 15%) is greater than a predetermined time (for example,
(0.6 seconds), it is determined that the accelerator opening is in the middle state, the value 1 is set to the switch SW (6), and the accelerator opening state is stored. Hereinafter, a procedure for setting the fuzzy input switch value SW (6) will be described with reference to FIG.

The electronic control unit 5 starts with step S11
0, the accelerator opening FV (4) is set to a predetermined value (CFV4
2) It is determined whether or not it is smaller. Step S110
Is affirmative, that is, if the accelerator opening is smaller than the predetermined value (CFV42), step S11 is performed.
Then, the process proceeds to 2 and the counter CNTSW6 is reset to a value of 0, and the value of the fuzzy input switch SW (6) and the value of the fuzzy input switch SW (8) are set to 0, thereby ending the routine. Fuzzy input switch SW
(8) is an accelerator high flag at the time of second-speed engine braking, and the fuzzy input switch S
Immediately after W (6) is set to the value 1 in this routine,
The accelerator opening FV (4) is equal to the aforementioned predetermined opening CFV43.
(For example, 40%) or more, the value is set to 1 (see FIG. 3).
Routine 3), the fact that the driver intends to accelerate strongly on a downhill is stored.

On the other hand, if it is determined in step S110 that the accelerator opening FV (4) is equal to or larger than the predetermined value (CFV42), the counter CNT is determined in step S114.
After incrementing the value of SW6 by 1, the counter value CNTSW6 becomes a predetermined value XCN7 (a value corresponding to 0.6 seconds).
Is determined (step S116). If the counter value CNTSW6 is smaller than the predetermined value XCN7, that is, if the predetermined time (0.6 seconds) has not elapsed, the routine ends without doing anything.

If it is determined in step S110 that the accelerator opening FV (4) is equal to or larger than the predetermined value (CFV42) and that the counter value CNTSW6 has reached the predetermined value XCN7 in step S116, the process proceeds to step S11.
8 is executed, the counter CNTSW6 is reset to the initial value 0, the value 1 is set to the fuzzy input switch SW (6), and the routine ends. By setting the value 1 to the fuzzy input switch SW (6),
The state during the accelerator opening is stored.

Fuzzy input switches SW (9) and S
W (10) is set to a value of 1 when it is determined that the friction coefficient μ of the traveling road surface is low.
W (9) uses the switch S
W (10) stores the long-term prediction results. Below, this fuzzy input switch value SW (9)
And the setting procedure of SW (10) will be described with reference to the flowcharts of FIGS.

First, the electronic control unit 5 executes step S25.
At 0, the road surface μ value is calculated. Various methods have been proposed for calculating the road surface μ. For example, a method of calculating the road surface μ disclosed in Japanese Patent Application Laid-Open No. 60-148769 (corresponding US Pat. No. 4,964,481) is based on an experimental method in which the relationship between the steering angle of the front wheels and the lateral acceleration is determined in advance using the road surface friction coefficient as a parameter. The road surface μ is predicted from the actually detected steering angle and lateral acceleration.

Further, another method for obtaining the road surface μ has been proposed. This alternative method uses a power steering pressure signal P
The road surface μ is calculated based on ST, the vehicle speed V0, and the steering wheel angle θw. The principle of the road surface μ calculation will be described below with reference to FIGS. 18 and 19. When the front wheel FW is steered, the right front wheel FW illustrated in FIG.
To the traveling direction of the _R, the inclination angle of the right front wheel FW _R, i.e., if the slip angle and .beta.f, cornering force C _F of the right front wheel FW _R can be expressed by the following equation.

[0087] Here C _F αβf · μ, as is apparent from the above equation, the cornering force C _F is proportional to the product of the slip angle βf and the road surface mu, the road surface mu is different, that is, the road surface Are different, the cornering force C _{F of the} wheel is greatly different even with the same side slip angle βf. Specifically, FIG.
As is clear from the above, in the region where the sideslip angle βf is large,
The higher the road surface μ, the larger the cornering force C _{F of the} wheel. Note that reference numeral 30 in FIG.
Denotes a front steering actuator, and 3 denotes a tie rod. Reference symbol L indicates a line along the axial direction of the vehicle body, and reference symbol δf indicates a right front wheel FW _R , that is,
This shows the steering angle of the front wheel FW.

As is apparent from FIG. 18, the cornering force C _F and the power steering pressure PST have a substantially proportional relationship in consideration of the dynamic equilibrium condition. Thus, by using the power steering pressure PST in place of the cornering force C _F, if rewritten the above equation, the following equation is obtained. PST = C ₁ · βf · μ (M1) Here, C ₁ is a constant.

On the other hand, the side slip angle βf can be expressed by the following equation using the vehicle speed V0, the steering wheel angle θw, and the road surface μ. ^{_{βf = C 3 · V0 2 ·}} θw / (μ + C 2 · V0 2) ... (M2) wherein, C _2, C ₃ are respectively constant. Formula (M1) and (M2)
From the equation, the power steering pressure PST and the steering wheel angle θw
, That is, PST / θw can be expressed by the following equation.

PST / θw = μ · C ₁ · C ₃ · V 0 ² / (μ + C ₂ · V 0 ² ) (M3) Therefore, the electronic control unit 5 supplies the supplied power steering pressure signal value PST and the steering wheel angle signal. By substituting the value θw and the vehicle speed signal value V0 into the above equation (M3), the road surface μ
Can be calculated. Next, step S2 in FIG.
52, and the control cycle (5
A histogram as shown in FIG. 20 is created from, for example, 100 pieces of road surface μ values detected every 0 msec), and a sum PBM of detection frequencies of road surface μ values smaller than a predetermined value XML (for example, 0.3) is calculated. Calculate. Then, it is determined whether or not the sum PBM of the detection frequencies is equal to or more than a predetermined value XMU (for example, 50%) (step S254). If the result of this determination is affirmative, the value of the fuzzy input switch SW (9) is set to 1 and the value of the short-term counter CNTMUS is reset to 0 assuming that the friction coefficient μ of the road surface is low ( Step S256). Short-term counter CNT
The MUS sets the fuzzy input switch SW (9) to the value 1 for a while (for example, 20 seconds) even if the detection frequency sum PBM becomes smaller than the predetermined value XMU and the determination condition of step S254 is not satisfied. It is for holding.

Therefore, the sum PBM of the detection frequencies is equal to the predetermined value XM
If it is smaller than U and the determination result in step S254 is negative, first, in step S258, it is determined whether or not the short-term counter value CNTMUS is equal to or greater than a predetermined value XCMS (a value corresponding to 20 seconds). If the predetermined time has not elapsed, step S260 is skipped and the fuzzy input switch SW (9) is held at the value 1, and step S262 is performed.
Proceed to. In step S262, the short-term counter CNTM
Increment the value of US to 1 Step S258
If the determination result is affirmative, the process proceeds to step S260,
Reset the fuzzy input switch SW (9) to the value 0. The fuzzy input switch SW (9) is reset to the value 0 after a lapse of a predetermined time (20 seconds) from the point in time when the sum PBM of the detection frequencies becomes smaller than the predetermined value XMU.

When the fuzzy input switch SW (9) is set to a value of 1, it means that the vehicle is running on a road surface having a small friction coefficient μ. As will be described in detail later, this switch SW (9) is used for speed change control such as early application of the engine brake when traveling on a downhill and prohibiting a shift change when turning on a curved road. You.

Next, the process proceeds to step S264 in FIG.
During the past TMU period, the fuzzy input switch SW
It is determined whether the state where (9) has the value 1 is equal to or more than a predetermined percentage (for example, 50%). The TMU period is a predetermined time (20 times) measured by the short-term counter value CNTMUS.
Second), for example, set to 20 minutes. If the determination result of step S264 is affirmative, step S264
At 266, the fuzzy input switch SW (10), which is the long-term low-μ road determination flag, is set to a value of 1. On the other hand, if not, the value is reset to 0 at step S268. The value of the fuzzy input switch SW (10) is stored in a non-volatile storage device whose storage is not erased even when the key switch is turned off and the engine 1 is stopped, and the value is read when the engine is restarted.

The value 1 is set to the fuzzy input switch SW (10).
Is set, it is assumed that the outside air temperature is low and the road surface is completely frozen, and in such a case, as described later in detail, the wheels do not slip when starting. Then, the shift control is automatically executed in a so-called snow mode, and the second speed start is performed. Then, step S
Proceed to 270 and set the fuzzy input switch SW (9) to the value 1
, That is, whether it is determined that the road surface is in the low μ state. If this determination is negative, that is, if the vehicle is in a normal road surface state, the process proceeds to step S272, and the threshold value P6 corresponding to the first α value, for example, α = 0.5, is obtained from the engine brake timing map.
1U, P62U, P63U, P82L, P82U are read and rewritten with these values. On the other hand, if the determination result in step S270 is affirmative, that is, if it is determined that the road surface is in the low μ state, the process proceeds to step S274, and the second value smaller than the first α value is determined from the engine brake timing map. α
Value, for example, each threshold value P61U, P62U, P63U corresponding to α = 0.1,
Read P82L and P82U and rewrite these values.

FIGS. 21A and 21B show an example of an engine brake timing map, and thresholds P61U, P62U,
The membership functions that define the relationship between P63U, P82L, and P82U (see Tables 5 and 7) and the variable α are shown. All of these thresholds are uniquely set by the same variable α, and when the α value is changed, the threshold values P61U, P62U, P63U, P8 corresponding to the α value are obtained from the map shown in FIG. 21 and a map similar thereto.
Set 2L and P82U respectively. Therefore, if the α value is set according to the road surface μ value, all the threshold values corresponding to the road surface μ can be set. As a result, as described later in detail, each membership function value of the fuzzy rule is set to the road surface μ.
Therefore, the timing of applying the engine brake on a downhill can be changed according to the road surface μ.

Determination of Rule Establishment In the shift control method of the present invention, the following fuzzy rules are determined to be established, and a control mode corresponding to the established rule is selected. Whether or not each fuzzy rule is satisfied must satisfy all of the following conditions. (1) All fuzzy input switches involved in the rule must be equal to the established value.

(2) All fuzzy input variables related to the rule are included in the range of the specified membership function. (3) The number of times the rule conforms to the specified number of times continuously Table 4 shows the fuzzy input switches involved in each fuzzy rule and their established values. Table 5 shows the fuzzy input variables involved in each fuzzy rule and the outline of each rule.
The membership function is a crisp set in this embodiment, and fuzzy inference is performed depending on whether or not the fuzzy input variable value is within a predetermined range value of each membership function.
Table 6 shows the control modes selected when the establishment of each fuzzy rule is confirmed.

[0098]

[Table 4]

[0099]

[Table 5]

[0100]

[Table 6] FIG. 22 shows a procedure for determining the establishment of the above-described fuzzy rule. First, in a rule matching determination routine, it is determined whether or not each rule matches each rule. In step (1), it is confirmed that the number of matching of the matching rule is continuously equal to or more than a predetermined number.

FIG. 23 shows a more specific procedure of the rule matching determination. When this routine is executed, the electronic control unit 5 first resets the program control variable n to a value 0 in step S120. Next, it is determined whether or not all the fuzzy input switches of the rule n conform (step S121). For example, in rule 0, Table 4
From the above, it is determined whether or not the fuzzy input switch SW (1) is equal to the established value 1. For example, in rule 8, it is determined whether or not the fuzzy input switch SW (0) and the fuzzy input switch SW (4) are equal to the established values 2 and 1, respectively, and it is determined whether or not all of them are established. become.

If it is determined in step S121 that at least one of the fuzzy input switches involved in rule n does not match, the flow advances to step S123 to control the control variable TEK.
Set the value 0 to I (n). On the other hand, step S121
When all the fuzzy input switches related to the rule n are suitable, the process proceeds to step S122. This time, all the fuzzy input variables related to the rule n are suitable, that is, the fuzzy input variable is specified. It is determined whether or not the value is within a predetermined range of the membership function.

For example, as shown in Table 5, rule 0
Determines the match of five fuzzy input variables, and Rule 4 determines the match of four fuzzy input variables. The proposition that the fuzzy input variable FV (0) is small, that is, whether or not the vehicle speed is low, is based on the 0th membership function prepared corresponding to this fuzzy input variable. Within specified upper and lower limits (for example, 10 km / h
It is inferred by whether the value is within the range of not less than r and not more than 55 km / hr). Similarly, the fuzzy input variable F
The proposition of whether or not V (0) is medium, that is, whether or not the vehicle speed is medium, is based on the first membership function prepared corresponding to this fuzzy input variable. Within the value range (for example, 30 km / hr or more and 1
00 km / hr or less). Table 7 shows the relationship between such a proposition and the membership function.

[0104]

[Table 7] If the determination result in step S122 is negative, the process proceeds to step S123, and the control variable TEKI (n)
To the control variable TEKI (n) if affirmative, that is, if all of the fuzzy input switches of rule n match and all of the fuzzy input variables of rule n match. Is set, and the fact that the rule n has been met is stored.

When the conformity determination of one rule is completed, the program control variable n is incremented by 1 in step S126, and the variable value n is changed to a predetermined value CRUL.
It is determined whether or not it is equal to (the value corresponding to the number of rules), and the above-described steps from step S121 are repeatedly executed until the variable value n reaches the predetermined value CRUL, thereby determining whether or not all the rules match. . When the conformity determination of all rules is completed and the determination result in step S128 is affirmative, the routine ends.

Here, the conformity with the rules 2 to 4 is a condition for entering the downhill weak engine brake mode 2.
The entry into the mode 2 means that the shift speed is forcibly set to the third speed and the engine brake is activated. Referring to Tables 5 and 7, in order to conform to Rule 2, the weight gradient resistance FV (6) is negative and the vehicle speed difference 2 seconds FV
(8) indicates that it needs to be large. Rule 3
, The weight gradient resistance FV (6) must be negative, and Rule 4 requires that the weight gradient resistance FV (6) be negative and large, and that the vehicle speed 2 second difference FV (8) be large. It indicates that there is. Further, the conformity with the rules 6 to 8 is a condition for entering the downhill strong engine brake mode 3. The entry into the mode 3 means that the shift speed is forcibly set to the second speed and the strong engine brake is applied. In order to conform to the rule 6, the weight gradient resistance FV (6) must be negative and extra large, and the vehicle speed 2 second difference FV (8) must be large. Rule 7 conforms that the weight gradient resistance FV (6) is negative and extra large, and Rule 8 conforms is that the weight gradient resistance FV
(6) indicates that must be negative.

The proposition "whether the weight gradient resistance FV (6) is negative" or the proposition "whether the vehicle speed 2 second difference (acceleration) FV (8) is large" is determined by each fuzzy It is determined by determining whether the input variable falls within a predetermined range defined by a threshold value of the corresponding membership function. Since this threshold value is set according to the road surface μ in the routine shown in FIGS.
Is determined to be low, these rules are easily adapted, and the timing for applying the engine brake is set earlier.

FIG. 24 is a routine for checking whether or not it has been determined that the matched rule has been continuously matched for a predetermined number of times. The electronic control unit 5 first sets the program control variable in step S130. Reset n to value 0. Next, in step S131, it is determined whether or not the control variable TEKI (n) corresponding to the rule n specified in step S130 is 0. If the control variable TEKI (n) is equal to 0 in step S131, the rule n is not suitable, and the process proceeds to step S132, where the counter C for the rule n is set.
NT (n) is reset to a value of 0, a value of 0 is set to a control variable SRT (n) for storing the establishment of the rule n, and the process proceeds to step S136 described later.

On the other hand, if the decision result in the step S131 is negative, the control variable TEKI (n) corresponding to the rule n becomes 0
If not, the process proceeds to step S133, where the counter value CN
After incrementing T (n) by one, it is determined whether or not the counter value CNT (n) has reached a predetermined value XCMAX (n) set in accordance with the rule n (step S134). . If the counter value CNT (n) has not reached the predetermined value XCMAX (n), the variable value S
The process proceeds to step S136 without changing RT (n).
The predetermined value XCMAX (n) is appropriately set in consideration of the degree of urgency of execution of the control mode, the degree of influence of determination of rule establishment due to noise, and the like.

When one matching rule check is completed,
In step S136, the program control variable n is set to the value 1
After incrementing the variable n by a predetermined value CRUL
It is determined whether or not the value is equal to (the value corresponding to the number of rules) (step S138), and the above-described steps from step S131 are repeatedly executed until the variable value n reaches the predetermined value CRUL. Perform a matching rule check. When the matching rule check of all the rules is completed, and the determination result in the step S138 is affirmative, the routine ends.

As described above, if the routine is repeated and the control variable TEKI (n) corresponding to the specific rule n is continuously set to the value 1, the counter value CNT
(N) is incremented each time the routine is executed, and finally reaches a predetermined value XCMAX (n). If the decision result in the step S134 is affirmative,
Step S135 is executed to reset the counter CNT (n) to the value 0 and to set the value 1 to the control variable SRT (n) that stores the establishment of the rule n.

Each mode processing When the rule established as described above is determined, next,
The electronic control unit 5 performs each mode process according to the procedure shown in FIG. More specifically, first, step S140
In the program variable X, the fuzzy input switch S
Set the value of W (0). That is, the current control mode is specified. Then, a processing routine corresponding to the current control mode X is executed (step S142).

Current Mode 0 Processing Routine When the current shift control is performed in control mode 0 (normal mode 0), the fuzzy shift position SHIFF is set according to the flowcharts of FIGS. In the control mode 0, as described above, the shift speed is set using the normal shift pattern for traveling on a flat road. From this control mode, as shown in FIG.
Transition to mode 1, mode 2, and mode 4 is possible.

The electronic control unit 5 starts with step S15
0, a control variable SRT that stores the establishment of the rule
It is determined whether any of (2), SRT (3), and SRT (4) has a value of 1. These variables store the establishment of rules 2, 3, and 4, respectively, and as shown in Table 6, when any one of these rules is established, the mode 2
Indicates that you should enter. Therefore, step S1
If the determination result at 50 is affirmative, the process proceeds to step S151, where the fuzzy input switch SW (0) is set to the value 2, the fuzzy shift position variable SHIFF is set to the value 3, and the routine ends. Mode 2, as described above, is a mode in which the vehicle is forced to descend on a downhill while applying the engine brake at the third speed.

Control variables SRT (2), SRT (3), S
If none of RT (4) is the value 1 and the determination result of step S150 is negative, step S152 is executed, and one of the variables SRT (0) and SRT (1) is set to the value 1
Is determined. These variables store the establishment of rules 0 and 1, respectively. As shown in Table 6, when any one of these rules is established, it indicates that mode 1 should be entered. Therefore, step S15
If the determination result of step 2 is affirmative, step S1 in FIG.
Proceeding to 54, the fuzzy input switch SW (0) is set to the value 1. Then, the process proceeds to step S155, in which the variable S representing the shift position (the operation shift speed of mode 0) determined by the shift pattern used in mode 0 described above.
It is determined whether or not HIF1 is a value 4 indicating the fourth speed. If the answer to this determination is affirmative, the gear is forcibly changed to 3
In order to shift down to the gear, the value 3 is set to the fuzzy shift position variable SHIFF, and the routine ends. On the other hand, if the decision result in the step S155 is negative, the process advances to a step S156 to set the variable value SHIF1 to the fuzzy shift position variable SHIFF and ends the routine. Mode 1 is an uphill corner mode as shown in FIG. 1, and the shift speed is determined by using a shift pattern in which the range of operation in the second and third speeds described later is widened. When shifting from mode 0 to mode 1, 4
When the vehicle is operating at the first gear, a downshift is instructed to the third gear, and the shift pattern is switched from the normal mode shift pattern to the uphill corner mode shift operation during this downshift operation. When the vehicle is operated at a speed other than the fourth speed, the shift pattern is switched while the speed is maintained.

Control variables SRT (0) and SRT (1)
Are not the value 1 and the determination result of step S152 is negative, the process proceeds to step S160, and the control variable SRT
It is determined whether or not (5) is the value 1. This variable stores the establishment of the rule 5, and indicates that the mode should be entered when the rule is established as shown in Table 6. Therefore, if the determination result in step S160 is affirmative, the process proceeds to step S162, in which it is determined whether the shift position variable SHIF1 determined by the shift pattern used in mode 0 is a value 4 indicating the fourth gear. I do. If the answer to this determination is affirmative, the value of the fuzzy shift position variable SHIFF is set to 3 by setting the fuzzy input switch SW (0) to a value of 4 and forcibly downshifting by one speed according to the current shift speed. Is set and the routine ends.

On the other hand, if the decision result in the step S162 is negative, the process proceeds to a step S165 to decide whether or not the shift position variable (mode 0 operation shift speed) SHIF1 is a value 3 indicating the third speed. . If the answer to this determination is affirmative, the value of the fuzzy shift position variable SHIFF is set to 2 in order to set the fuzzy input switch SW (0) to the value 4 and to forcibly downshift the shift speed to the second speed. Is set and the routine ends. As described above, in the mode 4 that is the straight uphill mode, the gear set by the shift pattern used in the normal mode 0 is forced to the third gear if the gear is the fourth gear, and to the second gear if the gear is the third gear. This is to shift down temporarily.

On the other hand, if the shift position variable SHIF1 is not the fourth speed stage or the third speed stage, the flow advances to step S168 to hold the fuzzy input switch SW (0) at the value 0 and to execute the fuzzy shift position variable The value 5 is set to SHIFF, and the routine ends. Setting the fuzzy shift position variable SHIFF to a value of 5 means shifting the shift speed to the fifth speed, but since the fifth speed does not actually exist in the transmission 3, the fuzzy shift position variable SHIFF is set. Is ignored, and the shift control in the normal mode 0 is executed.

If the control variable SRT (5) is not the value 1 and the decision result in the step S160 is negative, the process proceeds to the aforementioned step S168, in which the fuzzy input switch SW is set.
(0) is maintained at 0, and the value of the fuzzy shift position variable SHIFF is set to 5 to set the normal mode 0
Continue running. Current Mode 1 Processing Routine When the current shift control is performed in the control mode 1, the shift speed is set according to the flowcharts of FIGS. In the control mode 1, as described above, the gear position is set using the shift pattern for the ascending corner mode, and from this control mode, as shown in FIG. Migration is possible.

First, the electronic control unit 5 executes step S17.
At 0, it is determined whether or not the vehicle speed FV (0) is lower than a predetermined value CFV0 (for example, 10 km / hr). If the determination result is affirmative, the process proceeds to step S171 to set the value of the fuzzy input switch SW (0) to 0, set the value of the fuzzy shift position variable SHIFF to 5 and shift to the normal mode 0. When the vehicle speed is low, the normal mode 0 may be unconditionally executed.

If the vehicle speed FV (0) is larger than the predetermined value CFV0 and the determination result of step S170 is negative, the process proceeds to step S172, where the detected vehicle speed V0 and the accelerator speed are determined by using the up-slope corner mode shift pattern. The current shift position N is determined by the opening (throttle opening) APS.
Is calculated. FIG. 30 shows a shift pattern for upshifting from the second gear to the third gear and from the third gear to the fourth gear. When the control mode shifts from normal mode 0 to uphill corner mode 1, an upshift is performed. The line is changed as indicated by the arrow in the figure, and the operating range at the second speed or the third speed is expanded. In more detail, although 2 upshift line to the third speed in the normal mode 0 (indicated by a solid line) are partitioned two shift areas at the vehicle speed V ₂₃₀ constant linear, the vehicle speed constant linear There the uphill cornering mode 1 upshift line (indicated by a broken line), the process proceeds to the vehicle speed V ₂₃₀ is larger than the vehicle speed V ₂₃₁ constant linear, 2 speed region is enlarged. Similarly, (shown by a solid line) upshift line from the third speed to fourth speed in the normal mode 0 is that partitions the two shift areas at a constant linear speed V _340, the vehicle speed constant line uphill cornering mode In the upshift line 1 (shown by a broken line), the vehicle shifts to a vehicle speed V ₃₄₁ constant line that is higher than the vehicle speed V ₃₄₀ ,
The third speed range has been expanded. The calculation of the shift position N in step S172 is performed using a shift pattern indicated by a broken upshift line in FIG. The manner in which the second speed or third speed region is expanded by shifting from the normal mode to the uphill corner mode is indicated by the hatched region A in FIG.

Next, the electronic control unit 5 calculates the shift position from the detected vehicle speed V0 and the accelerator opening (throttle opening) APS using the normal shift pattern of the normal mode 0 shown by the solid line in FIG. At this time, it is determined whether or not an upshift from the second gear to the third gear or from the third gear to the fourth gear is performed. If the upshift occurs, a value 1 is set to a variable FLGYN (step S17).
3). In the shift control in mode 1, as described above, the value 1 is set to the fuzzy input switch SW (0) and the shift is forcibly changed to the third speed or a lower speed using the fuzzy shift position variable SHIFF. Command. Setting the value 1 to the variable FLGYN is equivalent to setting the variable SH
If there is no command from the IFF, it indicates that the shift position has changed such that the upshift is executed. This will be described with reference to FIG. 31. A region in which a new shift position is surrounded by an upshift line in normal mode 0 (solid line) and an upshift line in mode 1 (dashed line) due to a change in the shift position (A region indicated by oblique lines) Means that it has entered. This shift of the shift position may be as shown by an arrow TR1 in FIG. 31, the driver may release his / her foot from the accelerator petal, and the accelerator opening APS may become small to enter the area A, or as shown by an arrow TR2. Thus, the vehicle speed V0 may increase and enter the area A.

As described above, the calculation of the shift position N in step S172 and the storage of whether or not the shift-up has occurred by the variable FLGYN in step S173 are performed at the time of shifting from the control mode 1 to another mode. This is for selecting when the vehicle crosses the upshift line, and changing the control mode at such timing prevents the driver from feeling uncomfortable.

Next, the electronic control unit 5 determines that the fuzzy input switch SW (3) has the value 1 and the steering wheel angle FV
It is determined whether (9) is smaller than a predetermined value CFV9 (for example, 50 °) and whether the lateral acceleration FV (10) is smaller than the predetermined CFV10 (step S174). That is, it is determined whether or not the ascending slope is completed and the road is not bent. If this determination is negative, the process proceeds to step S180 in FIG. 29 described below.
On the other hand, if the determination result in the step S174 is affirmative,
Proceeding to step S175, whether the shift position N determined by the shift pattern in the uphill corner mode 1 is greater than the fuzzy shift position variable value SHIFF or the flag FLGYN indicating that an upshift has occurred is 1 Is determined. If any of these determinations is negative, the process proceeds to step S180 described later, and if one of the conditions is satisfied, the process proceeds to step S176.

At step S176, control variables SRT (2), SRT (3), SRT
It is determined whether any of (4) is the value 1 or not. As described above, these variables store the establishment of rules 2, 3, and 4, respectively. As shown in Table 6, when any one of these rules is established, it indicates that mode 2 should be entered. ing. Therefore, if the determination result in step S176 is affirmative, the process proceeds to step S177, in which the fuzzy input switch SW (0) is set to the value 2, the fuzzy shift position variable SHIFF is set to the value 3, and the routine ends. I do. Mode 2 is a mode for forcibly descending the downhill at the third speed as described above.

Control variables SRT (2), SRT (3), S
If any of RT (4) is not the value 1 and the determination result of the step S176 is negative, the step S178 is executed, the fuzzy input switch SW (0) is set to the value 0, and the fuzzy shift position variable SHIFF is set. The value 5 is set and the routine ends. In this case, the control mode is shifted from the uphill corner mode 1 to the normal mode 0.

Steps S174 and S175
Is executed if the result of the determination is negative in any of
In step S180 of FIG. 29, first, it is determined whether or not the shift position N calculated in step S172 is 3 or more. If the determination is negative, the process proceeds to step S184 described below, and if the determination is positive, the process proceeds to step S181. In step S181, it is determined whether or not any of the control variables SRT (2), SRT (3), and SRT (4) has the value 1. As described above, these variables store the establishment of the rules 2, 3, and 4, respectively, and indicate that the mode 2 should be entered when any one of these rules is established. Therefore, when both the determination results of step S180 and step S181 are affirmative, the process proceeds to step S182, where the fuzzy input switch SW (0) is set to the value 2 and the fuzzy shift position variable SHIFF is set to the value 3 The routine ends. Thus, the control mode 2 is executed.

Steps S180 and S181
Is negative, it means that the uphill corner mode 1 is continued. In this case, in steps S184 and S185, the shift position N is equal to 4 and the variable SRT (0 ) And SRT (1) are determined to be 1 or not. The variables SRT (0) and SRT (1) store the establishment of rules 0 and 1, respectively, as described above.
If any one of these rules is satisfied, it indicates that mode 1 should be executed. The shift position calculated by the shift pattern for the uphill corner mode 1 is not the fourth speed,
Alternatively, if neither of the variables SRT (0) and SRT (1) is equal to the value 1, that is, if one of the determination results of step S184 and step S185 is negative, the process proceeds to step S186 and the fuzzy shift is performed. The value N is set to the position variable SHIFF, and the routine ends.

When shift position N is 4 and variable SR
If either T (0) or SRT (1) has the value 1, the shift control in the uphill corner mode is executed again in the same mode 1, and the fuzzy shift position variable SHIF is changed.
A value of 3 is set to F, and downshifting from the fourth gear to the third gear is performed. When the shift control in the uphill corner mode is executed, when the vehicle enters the uphill section of the uphill road, even if the accelerator opening is returned, the upshift line shifts so that the upshift operation is difficult to execute. This will be described with reference to FIG. 31. When the shift control shifts from mode 0 to mode 1,
The speed change area indicated by oblique line A is enlarged. On an uphill road that bends frequently, the operating line indicated by the driver's accelerator pedal operation and the vehicle speed draws a circle, and this circle is shown in FIG.
This often occurs in the hatched area A shown in FIG. As a result,
Even when the ascending curved road is continuous, the number of times the upshift is executed is reduced, and shift hunting is less likely to occur.

Current Mode 2 Processing Routine When the current shift control is performed in the control mode 2, the shift speed is set according to the flowchart of FIG.
As described above, the control mode 2 is a downhill weak engine brake mode in which the vehicle goes downhill by holding down the third gear, but depending on how much the accelerator pedal is depressed, 1
It may be shifted to the fourth gear. This control mode 2
From, the transition to mode 0 and mode 3 is possible as shown in FIG.

First, the electronic control unit 5 executes step S19.
0, the control variable SRT (9) has the value 1;
The value of the fuzzy input switch SW (5) is 1, and the vehicle speed FV (0) is a predetermined value CFV0 (for example, 10 km
/ hr) is determined. The control variable SRT (9) stores the establishment of the rule 9, and as shown in Table 6, indicates that the mode should be shifted to the mode 0 when the rule 9 is established. The fuzzy input switch SW (5) stores that the accelerator opening is in a large state. Step S190
If at least one of the determination conditions is satisfied, step S191 is executed to set the fuzzy input switch SW (0) to the value 0 and to set the fuzzy shift position variable SHIFF to the value 5
Is set and the routine ends. In this case, the control mode is shifted from the weak downhill engine brake mode 2 to the normal mode 0.

If the decision result in the step S190 is negative, the process proceeds to a step S192, where the fuzzy input switch S
W (5) has a value of 1, accelerator opening FV (4) is smaller than a predetermined value CFV43 (for example, 40%), and fuzzy input switch SW (7) has a value of 0. It is determined whether all the conditions are satisfied. As described above, the fuzzy input switch SW (5) stores that the accelerator opening is in the large state. Also,
The fuzzy input switch SW (7) is set to a value of 1 when the accelerator is strongly depressed during the third-speed engine braking, and stores the state. Therefore, when the fuzzy input switch SW (7) is 0, it means that the accelerator pedal has not been strongly depressed. That is, in step S192, the driver's moderate acceleration intention is determined. If this determination result is affirmative, the process proceeds to step S191, where the fuzzy input switch SW
(0) is set to the value 0, and the value 5 is set to the fuzzy shift position variable SHIFF to shift to the normal mode 0. In this case, the shift speed is determined using the shifted normal mode shift map.
According to the accelerator opening and the vehicle speed, the vehicle is held at the third speed or shifted up to the fourth speed. When the gear is shifted up to the fourth gear, the amount of depression of the accelerator is reduced, and a feeling of acceleration suitable for the driver's intention to accelerate on a downhill is obtained.

If the decision result in the step S192 is negative, the process proceeds to a step S193, in which the value of the fuzzy input switch SW (5) is 1, and the accelerator opening F
It is determined whether or not V (4) is larger than the predetermined value CFV43 (40%). This is to determine the driver's intention to accelerate strongly. If the result of this determination is affirmative, step S194 is executed to set the value 1 to the fuzzy input switch SW (7) and the routine ends. In this case, the third speed is maintained, the shift control in mode 2 is continued, and strong acceleration on a downhill is performed. Mode 2 is a shift control mode in a case where the vehicle goes down a gentle slope while applying a weak engine brake. It is predicted that if the driver accelerates the vehicle strongly during such driving, and then enters a corner, strong braking is required.
The fuzzy input switch SW (7) is used as a flag for instructing a strong engine brake at the time of a forced operation after strong acceleration. That is, by setting the value 1 to the fuzzy input switch SW (7), the accelerator opening is in a large state by the fuzzy input switch SW (5), and the accelerator opening is set to the predetermined value CFV43 (40%).
Even if it is smaller, the aforementioned step S192
Is negative, the speed change control in the normal mode 0 in step S191 is not executed, and as described later, the downhill weak engine brake mode 2 or the downhill strong engine brake mode 3 of the current control mode. Is executed, and the number of brake operations can be reduced.

If the decision result in the step S193 is negative, a step S196 is executed to control variables SRT (6), SRT (7), SRT (8) for storing the establishment of the rule.
Is determined as to whether any of them is the value 1. As described above, these variables store the establishment of rules 6, 7, and 8, respectively. As shown in Table 6, when any one of these rules is established, it indicates that mode 3 should be entered. ing. Therefore, if the determination result in step S196 is affirmative, the process proceeds to step S198, in which the fuzzy input switch SW (0) is set to the value 3, the fuzzy shift position variable SHIFF is set to the value 2, and the routine ends. I do. Mode 3 is a mode for forcibly descending downhill at the second speed as described above.

Control variables SRT (6), SRT (7), S
If any of RT (8) is not the value 1 and the determination result of step S196 is negative, the routine ends without doing anything. That is, the shift control in the current control mode 2 is continuously executed, and unnecessary shift change can be prevented. Current Mode 3 Processing Routine When the current shift control is performed in the control mode 3, the shift speed is set according to the flowchart of FIG.
As described above, the control mode 3 is a downhill strong engine brake mode in which the vehicle goes downhill by holding the second speed. From this control mode 3, as shown in FIG.
Transition to mode 0 and mode 2 is possible.

The electronic control unit 5 starts with step S20
0, the vehicle speed FV (0) becomes the predetermined value CFV0 (10 km
/ hr). If the vehicle speed FV (0) is smaller than the predetermined value CFV0, step S2 is unconditionally performed.
01, and sets the fuzzy input switch SW (0) to the value 0
And the fuzzy shift position variable SHIFF
Is set to the value 5, and the routine ends. in this case,
The control mode is shifted directly from the downhill strong engine brake mode 3 to the normal mode 0.

If the decision result in the step S200 is negative, the process proceeds to a step S202, where the fuzzy input switch S
W (2) has a value of 1 and accelerator opening FV (4)
Is greater than or equal to a predetermined value CFV44 (for example, 3%). As described above, the fuzzy input switch SW (2) stores that the weight / gradient resistance is in a non-negative state. That is, in step S202, it is determined whether or not the vehicle is returning from the downward slope and the accelerator petal is slightly depressed. If the answer to this determination is affirmative, the process proceeds to step S205 and the fuzzy The value 2 is set to the input switch SW (0), the value 0 is set to the fuzzy input switch SW (5), and the value 3 is set to the fuzzy shift position variable SHIFF to shift to the downhill weak engine brake mode 2.

If the decision result in the step S202 is negative, the process proceeds to a step S204, in which the value of the fuzzy input switch SW (6) is 1, and the accelerator opening F
V (4) is smaller than a predetermined value CFV45 (for example, 40%), and the fuzzy input switch SW (8) is set to a value of 0.
Is determined. Fuzzy input switch SW
As described above, (6) stores the middle state of the accelerator opening, and the fuzzy input switch SW (8) stores the accelerator depression at the time of the second-speed engine braking, as described later. Therefore, this determination is for determining the driver's moderate acceleration intention. If the determination result is affirmative, the process proceeds to step S205, where the fuzzy input switch SW (0) is set to the value 2 and the fuzzy input switch SW (0) is set to the value 2. The input switch SW (5) is set to a value of 0, and the fuzzy shift position variable SHIFF is set to a value of 3 to shift to downhill weak engine braking mode 2. That is,
The shift speed is shifted from the second speed to the third speed, and the accelerator depression amount is reduced as compared with the case of the second speed, so that a feeling of acceleration suitable for the driver's intention to accelerate on a downhill can be obtained.

If the decision result in the step S204 is negative, the value of the fuzzy input switch SW (6) is 1, and
The accelerator opening FV (4) is equal to the predetermined value CFV4.
It is determined whether it is greater than 5 (40%). This step is for determining the driver's intention to accelerate strongly. If the result of this determination is affirmative, step S208 is executed to set the value 1 to the fuzzy input switch SW (8) and the routine ends. In this case, the second speed is maintained, and the shift control in mode 3 is continued. This allows
High output according to the driver's intention to accelerate strongly on a downhill is obtained. Mode 3 is a shift control mode in a case where the vehicle goes down a steep hill while applying a strong engine brake. It is predicted that if the driver accelerates the vehicle strongly during such driving, and then enters a corner, strong braking is required. Fuzzy input switch SW
(8) is used as a flag for instructing a strong engine brake at the time of the forced movement coming after the strong acceleration. That is, by setting the value 1 to the fuzzy input switch SW (8), the accelerator opening is set to the predetermined value CFV45 (4).
0%), the result of the determination in step S204 is negative, and the downhill high engine brake mode 3, which is the current control mode, is always continued. Strong engine braking by the second gear is effective.

If the result of the determination in step S206 is negative, the routine ends without setting the value 1 to the fuzzy input switch SW (8). In this case, the second speed is maintained, and the shift control in mode 3 is continued, so that useless shift change can be prevented. Current Mode 4 Processing Routine When the current shift control is performed in the control mode 4, the shift speed is set according to the flowchart of FIG.
As described above, the control mode 4 is the straight uphill mode, and the shift position set by the shift pattern of the normal mode 0 is the third speed if the shift position is the fourth speed, and the second speed if the shift position is the third speed. The required driving force is obtained by downshifting to each step. From this control mode 4, as shown in FIG. 1, only a transition to mode 0 is possible.

The electronic control unit 5 starts with step S21.
0, the accelerator opening FV (4) is equal to a predetermined value CFV4
It is determined whether it is smaller than 5 (for example, 10%).
If the accelerator opening FV (4) is smaller than the predetermined value CFV45, step S212 is executed, the fuzzy input switch SW (0) is set to a value of 0, and the fuzzy shift position variable SHIFF is set to a value of 5 to set the value to 5. The routine ends. In this case, the control mode is shifted from the straight uphill mode 4 to the normal mode 0.

If the decision result in the step S210 is negative, the process proceeds to a step S214, and the accelerator opening FV (4)
Is smaller than a predetermined value CFV46 (for example, 25%),
In addition, the accelerator depression speed FV (5) is a negative predetermined value (−C
FV5) It is determined whether or not it is smaller. If both conditions are satisfied at the same time, the process proceeds to step S212, where the value of the fuzzy input switch SW (0) is set to 0, the value of the fuzzy shift position variable SHIFF is set to 5, and the mode is shifted to the normal mode 0.

If the decision result in the step S214 is negative, the routine is terminated without doing anything. In this case, the current control mode 4 is maintained as it is. Shift Position Output Processing As described above, when each mode processing is completed, a control signal is output to the operating hydraulic control device 4 based on the set shift position. 35 and 36 show a procedure for outputting a shift position control signal. The outline of the procedure for outputting the shift position control signal according to this flowchart is that the control signal is output only when it is necessary to change the current shift position after the fuzzy judgment is made as described above. Conditions for performing the operation are that a predetermined time (for example, 0.5 seconds) has elapsed since the previous shift change, that the absolute value of the steering wheel angle is equal to or less than a predetermined value, and that the absolute value of the lateral acceleration is equal to or less than a predetermined value. The shift position is not changed unless one of these conditions is satisfied.

More specifically, the electronic control unit 5 determines whether or not the 0.5 second counter value SFLG is larger than 0 in step S220.
The 0.5 second counter SFLG is a down counter for determining whether or not a predetermined time (0.5 seconds) has elapsed since the previous shift operation, and is reset to an initial value when the shift operation is performed. Therefore, if the determination result in step S220 is affirmative, the predetermined time (0.5 seconds) has not yet elapsed since the previous shift operation, and in such a case, the counter value SFLG is incremented by 1 in step S221. After decrementing, the routine ends. Even if a new shift position is set while the counter value SFLG is not counted down to 0, the shift operation to that shift position is not executed.

If a predetermined time has passed since the previous shift operation and the result of the determination in step S220 is negative, step S2
Proceeding to 22, it is determined whether or not the value of the fuzzy input switch SW (0) is a value other than 0. If the value of the switch SW (0) is not a value other than the value 0 and the value is 0, it means that the shift control is performed in the mode 0. In this case, the routine ends without doing anything. In the case of the normal mode 0, since the normal shift control is performed, it is not necessary to perform the interrupt shift control based on the fuzzy judgment. As described above, the shift position control signal is set to the operating hydraulic pressure by the separately prepared normal shift control program. Output to the control device 4.

If the value of the fuzzy input switch SW (0) is determined to be a value other than 0, and the result of the determination in the step S222 is affirmative, the process proceeds to a step S224, where the fuzzy shift position SHIFF and the shift pattern of the normal mode 0 are used. The smaller one of the gear stages SHIF1 to be set is selected, and this is set as a variable N as a shift position command value.
Even during the fuzzy control, the shift speed SHIF1 determined by the shift pattern used in the normal mode 0
Is smaller, that gear is selected with priority. That is, the shift speed SH in which the fuzzy shift position SHIFF is set from the shift pattern of the normal mode 0
Only when the speed is lower than IF1, the fuzzy shift position SHIFF is selected. Next, it is determined whether or not the value of the selected shift position command variable N is equal to the currently commanded shift speed SHIF0 (step S2).
26). If equal, there is no need to perform a shift operation, and the routine ends.

On the other hand, if the decision result in the step S226 is negative, the shift position command variable N is larger than the current command shift speed SHIF0, that is, the steering wheel absolute value FV (9) becomes larger than the predetermined value CFV9 at the time of shift-up. Is large and the absolute value of the lateral acceleration FV (10) is a predetermined value CF
It is determined whether or not any of the conditions is larger than V10 (step S228). If any of the conditions is satisfied, the determination result in the step S228 is affirmative, and in this case, the routine ends without changing the shift position, that is, without performing the gear shift. That is, when a shift-up command is to be issued by the shift position command variable N, whether the steering wheel angle is larger than a predetermined value,
Alternatively, when the absolute value of the lateral acceleration is larger than the predetermined value, the shift operation is prohibited.

If none of the conditions in step S228 are satisfied and the result of the determination is negative, the process proceeds to step S229, and if the fuzzy input switch SW (9) is 1, the absolute value of the steering wheel angle FV (9 ) Is larger than a predetermined value CFV9, and whether the absolute value of the lateral acceleration FV (10) is larger than a predetermined value CFV10 is determined. Fuzzy input switch SW
(9) is set to 1 when it is determined that the friction coefficient μ is low due to freezing of the road surface or the like, as described above. Then, whether the steering wheel absolute value FV (9) is larger than the predetermined value CFV9, and whether the lateral acceleration absolute value FV
If (10) is larger than the predetermined value CFV10, either condition is satisfied, which means that the vehicle is turning a corner. If the determination result in step S229 is affirmative, the routine is terminated and the shift operation by fuzzy shift control is not performed. That is, on a low μ road, when turning a corner, a shift shift is prohibited. If none of the conditions in step S229 is satisfied and the determination result is negative, step S230 in FIG. 36 is executed. In step S230, it is determined whether or not the shift position command variable N is greater than the value one step higher than the current command shift speed SHIF0, that is, whether or not the current shift position command variable N will shift up by two or more speeds at a time. Determine. If it is determined that the gear is to be shifted up by two gears or more at a time by the current shift position command variable N, the current shift up operation is performed in step S232.
The command variable value N is set to a value (SHIF0 + 1) in order to limit the shift speed to one higher than the current command shift speed SHIF0.
After that, the process proceeds to step S237 described later.

On the other hand, if the decision result in the step S230 is negative, the process proceeds to a step S234, in which the shift position command variable N is smaller than the value one step lower than the current commanded shift speed SHIF0, that is, the current shift speed. It is determined based on the position command variable N whether or not the gear is to be downshifted by more than one gear at a time. If the current shift position command variable N shifts down by two speeds or more at a time, in step S236, the current shift-up operation is limited to a shift speed one step lower than the current command shift speed SHIF0. In order to perform this, the command variable value N is set to a value (SHI
After resetting to F0-1), step S23 described later is performed.
Go to 7. If the decision result in the step S234 is negative, the value of the shift position command variable N is kept as it is, and the process proceeds to a step S237.

In the step S237, it is determined whether or not the fuzzy input switch (10), which is the long-term low-μ road determination flag, is set to a value of 1. The value of the fuzzy input switch (10) is stored in the aforementioned non-volatile battery backup RAM, and when the value is 1,
It means that the friction coefficient μ is low due to snow on the road surface or freezing. Therefore, if the determination result in step S237 is negative, the process directly proceeds to step S240 described below, but if the determination result is affirmative, the process proceeds to step S238 to determine whether the command variable N is equal to the value 1. When the command variable value N is equal to the value 1, that is, when the shift position to be output is the first speed, the routine is terminated and the downshift to the first speed is prohibited. If the decision result in the step S238 is negative, the command variable value N
If is not equal to the value 1, there is no particular problem and step S2
Proceed to 40.

Here, in the above-described step S226, the commanded shift speed N is compared with the current shift speed SHIF0.
Is executed. Therefore, in step S238, the event that the commanded shift speed N value is equal to 1 is caused by the current shift speed SHIF
0 cannot occur except for the second speed. Therefore, on a snowy road (when the condition of SW (10) = 1 is satisfied), for example, even if the vehicle speed is reduced and the first gear is selected from the shift pattern of the normal mode 0, step S23 is performed.
As a result of step S242 not being executed according to the determination in step 8,
The current gear stage SHIF0, that is, the second gear stage is maintained, and downshifting to the first gear stage is surely prohibited when traveling on a low μ road.

In step S240, a 0.5 second counter S
After resetting the value of FLG to a predetermined value XT1 (a value corresponding to 0.5 seconds), step S242 is executed, and a shift position control signal corresponding to the shift position command variable N is output to the operating hydraulic control device 4 and End the routine. Step S
The shift position control signal output at 240 is based on fuzzy control, and this signal has a higher priority than the shift position control signal output based on normal mode 0. An interrupt is executed.

Normal Mode Shift Control Next, a shift control procedure in normal mode 0 will be described.
This will be described with reference to the flowchart of the normal mode shift control routine shown in FIGS. The normal mode shift control routine is executed at a predetermined control cycle when the shift position of the shift lever detected by the shift position sensor 12 is switched to the drive (D) position. First, in step S280, the electronic control unit 5 determines whether or not the 0.5 second counter value SFLG is larger than 0. As the 0.5 second counter SFLG, the same counter as that used in the shift position output routine in the fuzzy control is used. As described above, the shift operation is prohibited until a predetermined time (0.5 seconds) has not elapsed since the previous shift operation. It is for doing. Therefore,
If the determination result in step S280 is positive,
The predetermined time (0.5 seconds) has not yet elapsed since the previous shift operation, and in such a case, the routine is immediately terminated. The counter value SFLG is decremented to 1 in the shift position output routine.

If the result of the determination in step S280 is negative after the lapse of a predetermined time from the previous shift operation, step S2
81, the vehicle speed FV (0) and the accelerator opening FV
(4) is read, and the read vehicle speed FV (0) is 0,
Further, it is determined whether or not the accelerator opening FV (4) is a value 0 (step S282). This determination is for determining whether the vehicle is stopped and whether the driver has depressed the accelerator pedal. If the determination result is affirmative, the process proceeds to step S284, in which the SHIF1 value is forcibly set to the value 2, that is, the second speed, as the commanded shift speed, and the process proceeds to step S285. As described above, when the shift lever is switched to the D range and the vehicle is stopped, shifting to the second gear prevents the creep phenomenon that occurs when the vehicle stops.

If the decision result in the step S282 is negative, that is, if the accelerator pedal is depressed for starting or the vehicle is running, the step S283 is performed.
To the mode 0 calculation shift stage SHIF corresponding to the vehicle speed FV (0) and the accelerator opening FV (4) from the normal mode 0 shift pattern stored in the storage device 5C.
Read 1 The shift pattern of normal mode 0 is
The optimum gear position region when the vehicle travels on a flat road such as an urban area is defined by the vehicle speed and the accelerator opening.

After calculating the shift speed SHIF1, next,
Proceeding to step S285 in FIG. 38, it is determined whether or not the value of the fuzzy input switch SW (0) is zero. If the value of the switch SW (0) is a value other than 0, it means fuzzy shift control in a mode other than the mode 0. In this case, the routine ends without doing anything. On the other hand, step S2
If the result of the determination at step 85 is affirmative and the normal mode is 0, the calculated shift speed SHIF1 is the currently selected shift speed S
It is determined whether it is equal to HIF0 (step S28).
6). If they are equal, there is no need to perform a shift operation,
The routine ends.

On the other hand, if the decision result in the step S286 is negative, the process proceeds to a step S288, and if the fuzzy input switch SW (9) is 1, the steering wheel absolute value FV (9) becomes larger than the predetermined value CFV9. It is determined whether any one of the following conditions is satisfied: whether the value is larger and whether the absolute value of the lateral acceleration FV (10) is larger than a predetermined value CFV10. As described above, the fuzzy input switch SW (9) is a switch for storing that the friction coefficient μ is low due to the freezing of the road surface or the like. As in the case of the shift position output routine shown in FIG. S288
If the determination result is affirmative, the routine ends and the shift operation by fuzzy shift control is not executed. That is, on a low μ road, when turning a corner, a shift shift is prohibited.

If the decision result in the step S288 is negative, a step S290 in FIG. 39 is executed. In step S290, it is determined whether or not the mode 0 operation shift speed SHIF1 is larger than a value one step higher than the current command shift speed SHIF0.
That is, it is determined whether or not the gear is shifted up by two or more gears at a time by the current calculation gear position SHIF1. If it is to be shifted up by two or more gears at a time by the current operation shift stage SHIF1, step S
At 292, in order to limit the current shift-up operation to a shift speed one step higher than the current command shift speed SHIF0, the arithmetic shift speed SHIF1 is set to a value (SHIF0 + 1).
After that, the process proceeds to step S298 described later.

On the other hand, if the decision result in the step S290 is negative, the process proceeds to a step S294, in which the mode 0 operation shift speed SHIF1 is changed to the current command shift speed SHIF0.
It is determined whether the value is smaller than the value one step lower than that, that is, whether the gear is shifted down by two or more speeds at a time by the current operation shift speed SHIF1. Current calculation gear SH
If it is to be shifted down by two speeds or more at once by IF1, in step S296, the current shift-up operation is performed by one step from the current commanded shift speed SHIF0.
In order to limit the shift speed to a lower shift speed, the calculation shift speed SHI
After resetting F1 to the value (SHIF0-1), the process proceeds to step S298 described later. If the decision result in the step S294 is negative, the value of the arithmetic gear stage SHIF1 is held as it is, and the process proceeds to a step S298.

In step S298, it is determined whether or not the fuzzy input switch (10), which is a long-term low-μ road determination flag, is set to a value of 1. The value of the fuzzy input switch (10) is stored in the non-volatile battery backup RAM as described above. When the value is 1, it means that the friction coefficient μ is low due to snow on the road surface or freezing. means. Therefore, if the determination result in step S298 is negative, the process directly proceeds to step S302 described below, but if the determination result is affirmative, the process proceeds to step S300 to determine whether or not the arithmetic gear stage SHIF1 is equal to the value 1. If the calculated shift stage SHIF1 is equal to the value 1, that is, if the shift position to be output is the first speed, the routine is terminated and downshifting to the first speed is prohibited. If the decision result in the step S300 is negative and the calculated shift speed SHIF1 is not equal to the value 1, there is no particular problem and the process proceeds to the step S302.

Considering the case where the shift lever is switched from the N range to the D range and the vehicle starts, in the normal mode shift control applied to this embodiment, the vehicle is stopped and the accelerator pedal is depressed. Unless otherwise, the gear is forcibly set to the second gear (step S284).
Prevents creep phenomenon. In this state, when the accelerator pedal is depressed and the accelerator opening FV (4) becomes larger than a predetermined minute value, the first speed is selected in step S283. If the shift operation is performed to the first gear at the time of starting, there is no problem on a normal pavement road, but on a snowy road, if the accelerator petal is stepped openly, the wheels may slip and it may be difficult to start. Even in such a case, according to the speed change control method of the present invention, in the above-described steps S298 and S300, the first gear is prohibited on the low μ road, so that 2nd gear set to prevent creep is set. The second gear is started while the second gear is maintained. In addition, it is needless to say that downshifting to the first gear is prohibited when traveling on a low μ road. Thus,
On low μ roads such as snowy roads, downshifting to the first gear is prohibited to facilitate starting on snowy roads and to prevent slippage during running.

In step S302, a 0.5 second counter S
After resetting the value of FLG to a predetermined value XT1 (a value corresponding to 0.5 second), step S304 is executed, and a shift position control signal corresponding to the arithmetic gear stage SHIF1 is output to the operating hydraulic control device 4 to execute the routine. To end.

[0163]

As is apparent from the above description, according to the shift control method of the automatic transmission for a vehicle of the present invention, when it is determined that the frictional resistance on the road surface is small, the vehicle is controlled during cornering of the vehicle. Since the change of the gear position is prohibited, the instability of the vehicle behavior due to the change in the driving force can be prevented, and the safe driving can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing the interrelation of each control mode executed by a shift control method for a vehicle automatic transmission according to the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a shift control device to which a shift control method for a vehicle automatic transmission according to the present invention is applied.

FIG. 3 is a flowchart of a main routine showing a procedure of fuzzy speed change control executed by an electronic control unit (ECU) shown in FIG. 2;

FIG. 4 is a handle operation amount FV used for fuzzy shift control.
It is a flowchart which shows the calculation procedure of (2).

FIG. 5 shows a brake deceleration width FV used for fuzzy shift control.
It is a flowchart which shows the calculation procedure of (3).

FIG. 6 shows accelerator depression speed F used for fuzzy shift control.
It is a flowchart which shows the calculation procedure of V (5).

FIG. 7 shows a weight / gradient resistance FV used for fuzzy speed change control.
It is a flowchart which shows the calculation procedure of (6).

FIG. 8 shows a two-second difference FV of the vehicle speed used for fuzzy shift control.
It is a flowchart which shows the calculation procedure of (8).

FIG. 9 is a flowchart showing a procedure for setting a fuzzy input switch SW (1) for storing a large gradient resistance state used for fuzzy shift control.

FIG. 10 is a flowchart showing a setting procedure of a fuzzy input switch SW (2) for storing a non-negative state of the gradient resistance used for fuzzy shift control.

FIG. 11 is a flowchart showing a procedure for setting a fuzzy input switch SW (3) for storing a non-large gradient resistance state, which is used for fuzzy shift control.

FIG. 12 is a part of a flowchart showing a setting procedure of a fuzzy input switch SW (4) for storing a winding state of a road used for fuzzy speed change control.

FIG. 13 is a remaining flowchart following the flowchart of FIG. 12;

FIG. 14 is a flowchart showing a setting procedure of a fuzzy input switch SW (5) for storing a large accelerator opening degree used in fuzzy shift control.

FIG. 15 is a flowchart showing a procedure for setting a fuzzy input switch SW (6) used for fuzzy shift control and for storing a state during accelerator opening.

FIG. 16 shows fuzzy input switches SW (9) and SW
It is a part of a flowchart showing the setting procedure of (10).

FIG. 17 is a remaining flowchart following the flowchart of FIG. 16;

FIG. 18 is a diagram showing a relationship between a sideslip angle of a front wheel and a cornering force thereof.

FIG. 19 is a graph showing a cornering force that varies depending on a road surface condition with respect to a sideslip angle.

FIG. 20 is a histogram as an example of a detected road surface μ.

FIG. 21 illustrates a membership function for simultaneously determining various thresholds based on the α value. FIG. 21A is a graph showing the relationship between the α value and the weight gradient resistance determination threshold P61U. B) is an α value and a vehicle speed 2 second difference determination threshold value P82L.
6 is a graph showing a relationship with the graph.

FIG. 22 is a flowchart of a rule establishment determination routine in fuzzy shift control.

FIG. 23 is a flowchart illustrating a procedure of a rule matching determination in a rule establishment determination.

FIG. 24 is a flowchart showing a procedure for checking a matching rule in rule establishment determination.

FIG. 25 is a flowchart showing the procedure of each mode.

FIG. 26 is a part of a flowchart showing a processing procedure when the current control mode is 0;

FIG. 27 is a remaining flowchart following the flowchart of FIG. 26.

FIG. 28 is a part of a flowchart showing a processing procedure when the current control mode is 1;

FIG. 29 is a remaining flowchart following the flowchart of FIG. 28.

FIG. 30 is a graph showing upshift lines in control modes 0 and 1, which define a shift region according to a throttle opening and a vehicle speed.

FIG. 31 is a graph for explaining a shift region that is enlarged as the mode shifts from control mode 0 to control mode 1.

FIG. 32 is a flowchart illustrating a processing procedure when the current control mode is 2.

FIG. 33 is a flowchart showing a processing procedure when the current control mode is 3.

FIG. 34 is a flowchart showing a processing procedure when the current control mode is 4.

FIG. 35 is a part of a flowchart showing a procedure for outputting a shift position control signal.

FIG. 36 is a remaining flowchart following the flowchart of FIG. 35.

FIG. 37 is a part of a flowchart showing a shift control procedure in normal mode 0.

FIG. 38 is a flowchart further illustrating a part of the flowchart shown in FIG. 37;

39 is a remaining flowchart following the flowchart shown in FIG. 38.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Torque converter 3 Gear transmission 4 Operating oil pressure control device 5 Electronic control device (ECU) 12 Shift position sensor 16 Brake sensor 18 Wheel speed sensor 20 Engine speed sensor 26 Handle angle sensor 28 Power steering pressure sensor

Claims (4)

(57) [Claims] 1. A shift control method for an automatic transmission for a vehicle, wherein a shift position of an automatic transmission having a plurality of shift speeds is switched from one shift speed to another shift speed, wherein a parameter relating to frictional resistance of a road surface is provided. The value is detected, it is determined whether the vehicle is cornering or not, and based on the parameter value related to the detected frictional resistance, it is determined that the road surface frictional resistance is small, and the vehicle is cornering. A shift control method for an automatic transmission for a vehicle, wherein the shift of the shift speed is prohibited when the shift is detected. 2. The method according to claim 1, wherein the frictional resistance of the road surface is constantly determined when the vehicle is running.
Detects related parameter values and detects parameters related to frictional resistance.
Based on the meter value, it is determined whether the frictional resistance of the road surface is small.
The vehicle automatic according to claim 1, wherein the determination is performed.
Transmission shift control method. 3. The frictional resistance detected during running of the vehicle
Relevant parameter values are stored and the first
Is the sum of the frequencies at which parameter values less than
When it is more than the predetermined value of 2, the frictional resistance of the road surface is small.
3. The vehicle according to claim 2, wherein
Shift control method for dynamic transmission. 4. The method according to claim 1, wherein the sum of the frequencies is equal to or less than the second predetermined value.
When the value drops to the value, the sum of the frequencies crosses the second predetermined value.
Until the first predetermined time elapses from the time when the
It is special to continue the determination that the frictional resistance of the road surface is small.
The shift control of the automatic transmission for a vehicle according to claim 3, wherein the shift is controlled.
Method.