JP3257357B2 - Control device for automatic transmission for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission for a vehicle, and more particularly to a control device for an automatic transmission for a vehicle capable of preventing an unintended upshift when a driving wheel is idling.

[0002]

2. Description of the Related Art In a vehicle, an automatic transmission is connected to an engine mounted on the vehicle, a vehicle speed sensor for detecting a vehicle speed which is the rotation speed of an output shaft of the automatic transmission is provided, and a vehicle speed signal of the vehicle speed sensor is shifted. There is a vehicle provided with a control device of an automatic transmission for a vehicle that performs a shift determination by using a gear (shift position) selection.

As a control device for such an automatic transmission, for example, Japanese Patent Publication No. Sho 60-10223,
No. 24360. Tokiko Sho 60-1
Japanese Patent No. 0223 discloses a road surface gradient during traveling determined by comparing a reference acceleration and an actually measured acceleration. In making a switch determination to a shift pattern that is optimal for the road surface gradient, both accelerations are determined as necessary. Compare the corrected reference acceleration obtained by calculating the predetermined value with the reference acceleration and the actually measured acceleration, or compare the corrected actual measured acceleration obtained by calculating the predetermined value with the actually measured acceleration and the reference acceleration. In addition, a hysteresis is set for the change of the shift pattern, and the unnecessary change of the shift pattern can be surely avoided without the inconvenience of delaying the change of the shift pattern. JP Hei 3
Japanese Patent Publication No. 24360 discloses a vehicle acceleration detection unit that detects the acceleration of a vehicle including its direction by a vehicle acceleration detection unit.
The shift control unit controls the shift in consideration of the information on the detected acceleration of the vehicle. For example, when the shift control unit includes a vehicle acceleration calculation unit and a slip shift control unit, The vehicle acceleration calculation means calculates the acceleration of the vehicle based on the vehicle speed detected from the vehicle drive system by the vehicle speed detection means, and the slip shift control means is detected by the calculated vehicle acceleration and the vehicle acceleration detection means. Comparing the acceleration in the longitudinal direction of the vehicle and determining that the vehicle is slipping when the former is greater than the latter,
When a shift pattern to be controlled to a gear position higher than usual is selected, and when the control means includes a hold-type shift control means, the lateral acceleration of the vehicle detected by the vehicle acceleration detection means When is large or when the average value of each detected speed per hour is large,
The shift point is set mainly based on the vehicle speed, and a hold-type shift pattern for fixedly controlling the gear position at a lower gear position below the intermediate vehicle speed is selected.

[0004]

However, in a conventional automatic transmission control device, when a wheel spin occurs on a road surface having a low road surface friction coefficient, a vehicle speed value calculated from a vehicle speed signal of a vehicle speed sensor is reduced. Because it rises suddenly,
Even if the ground speed of the vehicle does not increase, an unintended upshift is performed. Therefore, when the vehicle becomes unstable due to a sudden change in torque due to gear shifting, or when the driving force becomes insufficient when returning from wheel spin, or when the accelerator pedal is depressed due to insufficient driving force, a downshift is performed. This causes inconvenience that a so-called busy shift occurs.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an automatic transmission connected to an engine mounted on a vehicle, and the rotational speed of an output shaft of the automatic transmission is controlled by the vehicle speed. A vehicle speed sensor that detects and outputs a vehicle speed signal is provided, and the vehicle speed signal of the vehicle speed sensor is taken in as a speed change determination vehicle speed value, and is used for selecting a shift stage to determine a shift. A limit value of the acceleration of the vehicle is calculated for each time, a first vehicle speed value is calculated from the vehicle speed signal of the vehicle speed sensor for each fixed time, and a second vehicle speed value for the previous shift determination and the limit value of the acceleration are calculated. Calculating a vehicle speed value for comparison,
Comparing the vehicle speed value with the vehicle speed value for comparison, and when the first vehicle speed value is less than the vehicle speed value for comparison, sets the first vehicle speed value as a second vehicle speed value for current shift determination; First
If the vehicle speed value is equal to or higher than the comparison vehicle speed value, the comparison vehicle speed value is set as the current shift determination second vehicle speed value, and the current shift determination second vehicle speed value is selected so as to select a shift stage. A control means provided with a shift determining unit for determining a shift by means of the control unit.

[0006]

According to the configuration of the present invention, the limit value of the acceleration of the vehicle is calculated at regular time intervals, the first vehicle speed value is calculated from the vehicle speed signal of the vehicle speed sensor at regular time intervals, and the first speed value for the previous shift determination is calculated. 2. A vehicle speed value for comparison is calculated from the vehicle speed value and the limit value of the acceleration, and the first vehicle speed value is compared with the vehicle speed value for comparison. If the first vehicle speed value is less than the vehicle speed value for comparison, the first vehicle speed value is calculated. The value is used as the current speed change determination second vehicle speed value. When the first vehicle speed value is equal to or greater than the comparison vehicle speed value, the comparison vehicle speed value is used as the current shift determination second vehicle speed value, and the shift speed is determined. A shift determination is made based on the current shift determination second vehicle speed value so as to make a selection. As a result, even when the wheel spins on a road surface having a low coefficient of road surface friction, the first vehicle speed value calculated from the vehicle speed signal of the vehicle speed sensor does not rise sharply, and an unintended upshift during driving wheel idle rotation is prevented. be able to.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; 1 to 9 show an embodiment of the present invention. In FIG. 9, reference numeral 2 denotes an engine mounted on a vehicle (not shown), and reference numeral 4 denotes an automatic transmission connected to the engine 2. This automatic transmission 4 has a torque converter 6, a transmission 8, a final gear 10, and a hydraulic control device 12, as shown in FIG.

The hydraulic control device 12 includes a torque converter 6
The operation of the transmission 8 is controlled, and the oil pump 14 and the servo mechanism 16 for operating the transmission 8 are connected to each other. The vacuum diaphragm 18 connected to the engine 2 is connected to the hydraulic control device 12.

A first solenoid (solenoid A) 20 and a second solenoid (solenoid B) 22 are connected to the hydraulic control device 12.

The first and second solenoids 20, 22 are
The engagement of the gears of the transmission 8 is switched by the switching operation by the control means 24 (A / T controller).

The control means 24 includes a throttle opening sensor 28 for detecting the throttle opening state of the throttle valve 26 and an intake pipe pressure sensor 30 as engine output torque detecting means, and an output shaft of the automatic transmission 4. A vehicle speed sensor 32 that detects a rotation speed as a vehicle speed and outputs a vehicle speed signal; a crank angle sensor 34 that detects an engine speed; an oil temperature sensor 36 that detects the temperature of oil in the automatic transmission 4; The shift switch 38 for detecting the shift position of No. 4 is connected to an air conditioner switch 40 of an air conditioner (not shown).

The control means 24 controls the speed of the automatic transmission 4 by inputting various signals. The control means 24 takes in the vehicle speed signal of the vehicle speed sensor 32 as a vehicle speed value for determining the speed and uses it to select a shift speed. Make a decision.

The control means 24 calculates a limit value (dVSA) of the acceleration of the vehicle at predetermined time intervals, and obtains a first vehicle speed value (V) from the vehicle speed signal of the vehicle speed sensor 32 at predetermined time intervals.
S1) is calculated, and the previous second vehicle speed value for shift determination (VS
2 ′) and a limit value of acceleration (dVSA), a vehicle speed value for comparison (hereinafter referred to as “VS2 ′ + dVSA”), that is, a vehicle speed (shown by a broken line) to which the acceleration limit is applied in FIGS. Then, the calculated first vehicle speed value (VS
1) and the calculated vehicle speed value for comparison (VS2 ′ + dV)
SA), and when the first vehicle speed value (VS1) is smaller than the comparison vehicle speed value (VS2 ′ + dVSA), the first vehicle speed value (VS1) is changed to the current shift determination second vehicle speed value (VS2). When the first vehicle speed value (VS1) is equal to or greater than the comparison vehicle speed value (VS2 '+ dVSA), the comparison vehicle speed value (VS2' + dVSA) is changed to the current shift determination second vehicle speed value (VS2). ), And a shift determination unit 24a for determining a shift based on the current shift determination second vehicle speed value (VS2) so as to select a shift stage.

The above-mentioned vehicle acceleration limit value (dVSA)
Is a value that is equal to or greater than the acceleration when the drive wheels do not run idle as shown in FIG. 3, that is, the acceleration when the drive wheels are not running idle, and as shown in FIG. It is calculated. Further, the vehicle speed value for comparison (VS2 ′ + dVSA) is the same as the previous vehicle speed value for shift determination (VS2 ′) and the acceleration limit value (dV2 ′).
It is calculated by adding the value of the vehicle speed obtained corresponding to SA).

The throttle sensor 28 and the intake pipe pressure sensor 30 function as engine output torque detecting means, and output a detection signal to the control means 24. The crank angle sensor 34 detects the engine speed and outputs a detection signal to the control means 24.

Thus, the control means 24 calculates the speed ratio of the torque converter 6 from the engine speed, the gear ratio at each shift stage, and the rotation speed of the output shaft, and as shown in FIG. A torque ratio is calculated from a torque ratio-speed ratio table of the converter 6, and an output shaft output torque is calculated from the torque ratio, the engine output torque, and the gear ratio.

The control means 24 performs an upshift at a predetermined engine speed or higher so that the engine speed does not become excessive.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

In the program of the shift determining section 24a of the control means 24, when the routine for calculating the second vehicle speed value for shift determination (VS2) is started at regular intervals (step 102), first, the output shaft output torque shown in FIG. Is calculated (step 104), and the first vehicle speed value (VS1) is calculated from the vehicle speed signal of the vehicle speed sensor 32 (step 10).
6). Further, the second speed value (VS2 ') for the previous shift determination
The vehicle speed value (VS2 '+ dVSA) for comparison is calculated from the acceleration limit value (dVSA).

Then, the calculated first vehicle speed value (VS)
1) and the calculated vehicle speed value for comparison (VS2 ′ + dV)
SA) (step 108).

In this step 108, VS1 ≦ V
If the first vehicle speed value (VS1) is smaller than the comparison vehicle speed value (VS2 '+ dVSA) in S2' + dVSA, ie, YES, the process of VS1 → VS2, that is, the first vehicle speed value (VS
1) is set as the second vehicle speed value (VS2) for the current shift determination (step 110).

On the other hand, in step 108, VS1>
In the case of VS2 '+ dVSA, if the first vehicle speed value (VS1) is NO equal to or greater than the comparison vehicle speed value (VS2' + dVSA), the process of VS2 '+ dVSA → VS2, that is, the comparison vehicle speed value (VS2' + dVSA) ) Is set as the second speed value for shift determination (VS2) this time (step 112).

After the processing in steps 110 and 112, this program is terminated (step 11).
4).

In other words, in the flowchart of FIG. 1, the acceleration limit value (dVSA) is calculated from the table of FIG. 3 at regular intervals, and the first vehicle speed value (VS1) is calculated from the vehicle speed signal of the vehicle speed sensor 32. Then, a vehicle speed value for comparison (VS2 '+ dVSA) is calculated from the previous second vehicle speed value for shift determination (VS2') and the limit value of acceleration (dVSA), and is then compared with the first vehicle speed value (VS1). Vehicle speed value (VS
2 ′ + dVSA) and compare these first vehicle speed values (VS
1) and the vehicle speed value for comparison (VS2 ′ + dVSA), whichever is smaller, is used as the second vehicle speed value for shifting determination (VS
2).

As shown in FIG. 2, the acceleration of the vehicle speed calculated by the vehicle speed sensor 32 for detecting the rotation speed of the output shaft during the idling of the drive wheels is calculated as follows.
Focusing on the acceleration when the driving wheels are not idling, that is, greater than the acceleration of the ground speed of the vehicle body, if the acceleration is not more than the acceleration when the driving wheels are not idling, for example, on a road surface with a low road surface friction coefficient Further, even when the driving wheels are idling, the shift can be determined by calculating the vehicle speed substantially equal to the ground speed of the vehicle body, that is, by calculating a value close to the actual vehicle speed. As a result, an unintended upshift can be prevented.

In this case, the acceleration limit value (dVSA)
Is a first vehicle speed value (VS1) calculated from the vehicle speed signal of the vehicle speed sensor 32 during acceleration in a state where the drive wheels do not idle.
It is necessary to set the acceleration to be equal to or higher than the acceleration in a state where the drive wheels do not run idle in order to use the speed change in the shift determination.

The acceleration in a state where the drive wheels do not run idle is substantially determined by the output shaft output torque, and is stored as a table of the output shaft output torque in FIG.

The detection of the output shaft output torque may be performed by separately providing a torque sensor. However, since the torque sensor is expensive, as the engine output torque detecting means, for example, the existing intake pipe pressure sensor 30 or A throttle sensor 28 and, for example, an existing crank angle sensor 34 are provided as engine speed detecting means.

With these sensors, the torque converter 6
Rotation speed (same as engine rotation speed Ne) and turbine rotation speed (output shaft rotation speed No × gear ratio G)
From r), the speed ratio e is calculated as e = Ne / No × Gr.

The torque ratio (pump torque / turbine torque) of the torque converter 6 is, as shown in FIG.
Since this is determined by
The torque ratio is calculated from this characteristic.

Therefore, the output shaft output torque To is calculated by To = engine torque × torque ratio × gear ratio.

Of the sensors necessary for calculating the output shaft output torque, the intake pipe pressure sensor 30 and the crank angle sensor 34 are also used in normal engine control. be able to.

Thus, an unintended upshift can be prevented when the drive wheels are idling. However, when the accelerator pedal is continuously depressed despite the drive wheels being idling,
Since there is a possibility that the engine 2 may over-rotate, the engine 2 is controlled to perform an upshift at a predetermined rotational speed or higher to prevent this over-rotation.

As a result, the acceleration limit value (dVSA)
If the value is not equal to or greater than the actual acceleration of the actual vehicle, the actual vehicle value may be calculated to be low, for example, when accelerating with the throttle fully open. Therefore, when the acceleration limit value (dVSA) is set as a fixed value, as shown in FIG. 5, on a road surface having a high road surface friction coefficient, the value is equal to or higher than the acceleration when the throttle is fully opened and the vehicle is accelerated at the first speed. In addition, as shown in FIG. 6, acceleration cannot be performed on a road surface having a low coefficient of road friction, and the difference between the actual vehicle value and the drive wheel when the drive wheel idles on a road surface having a low coefficient of road friction is actually required. May increase.

In theory, if the driving force and the weight of the driving wheels are known, the acceleration on a flat road surface can be calculated.
If the values are integrated, actually, not only a flat road surface, but also the weight changes, so that there is an error, but the speed can be calculated. Therefore, the acceleration is substantially determined by the driving force and the weight of the driving wheels. If it is considered that the weight does not greatly change in the case of a passenger car, it is safe to assume that the weight is determined only by the driving force. Therefore, if the acceleration limit value is set in accordance with the driving force, FIG.
As shown in the figure, even when the vehicle idles on a road surface having a low coefficient of road surface friction, the value can be reduced to substantially the actual vehicle value.

As shown in FIG. 8, the acceleration limit value (dVS
Since A) is calculated according to the output shaft output torque, the driving force (drive torque) of the drive wheels may be set to a value corresponding to the output shaft output torque, thereby simplifying the calculation.

Although a torque sensor may be used to detect the output shaft output torque, it is necessary to use a separate torque sensor. Therefore, the gear ratio and the torque ratio of the torque converter 6 can be calculated from the engine output torque. This eliminates the need for a torque sensor, and allows the engine output torque to be calculated almost accurately from the intake air amount, the throttle opening, and the like, thereby reducing the cost.

Further, even if the vehicle speed signal of the vehicle speed sensor 32 is apparently temporarily accelerated due to noise or the like and suddenly accelerates, even if noise is included in the vehicle speed signal, no upshift is performed.
It is valid.

[0039]

As apparent from the above detailed description, according to the present invention, the limit value of the acceleration of the vehicle is calculated at regular intervals, and the first value is obtained from the vehicle speed signal of the vehicle speed sensor at regular intervals.
A vehicle speed value is calculated, a vehicle speed value for comparison is calculated from the second vehicle speed value for the previous shift determination and the limit value of acceleration, and the first vehicle speed value is compared with the vehicle speed value for comparison. When the vehicle speed is lower than the vehicle speed for comparison, the first vehicle speed is used as the second vehicle speed for the current shift determination. When the first vehicle speed is higher than the vehicle speed for comparison, the vehicle speed for comparison is changed to the current vehicle speed. By providing a control means provided with a shift determining unit for determining a shift based on the current shift determining second vehicle speed value so as to select the shift speed as the shift determining second vehicle speed value, the road surface friction coefficient is increased. It is possible to prevent an unintended upshift at the time of idling of the drive wheels, for example, when wheel spin occurs on a low road surface.

[Brief description of the drawings]

FIG. 1 is a flowchart of control of an automatic transmission.

FIG. 2 is a time chart of control of the automatic transmission.

FIG. 3 is a diagram showing a relationship between a limit value of acceleration and an output shaft output torque.

FIG. 4 is a diagram showing a relationship between a torque ratio and a speed ratio.

FIG. 5 is a diagram illustrating a relationship between vehicle speed and time on a road surface having a high coefficient of road surface friction.

FIG. 6 is a diagram illustrating a relationship between vehicle speed and time on a road surface having a low coefficient of road surface friction.

FIG. 7 is a diagram showing a relationship between vehicle speed and time on a road surface having a low road surface friction coefficient.

FIG. 8 is a diagram illustrating a relationship between an output shaft output torque and a limit value of acceleration.

FIG. 9 is a block diagram of a control device of the automatic transmission.

[Explanation of symbols]

 Reference Signs List 2 engine 4 automatic transmission 24 control means 24a shift determination unit 28 throttle opening sensor 32 vehicle speed sensor 34 crank angle sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-3775 (JP, A) JP-A-4-64764 (JP, A) JP-A-56-10850 (JP, A) JP-A-3-3 24360 (JP, A) JP-A-6-346953 (JP, A) JP-A-5-231521 (JP, A) JP-A-5-223157 (JP, A) JP-A-5-340468 (JP, A) JP-A-5-272630 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63 / 48

Claims (3)

(57) [Claims] An automatic transmission is connected to an engine mounted on a vehicle, and an output shaft of the automatic transmission is provided.
Of the rotational speed is detected as the vehicle speed provided vehicle speed sensor for outputting a vehicle speed signal, a shift determination vehicle speed signal from the speed sensor
The control apparatus for a vehicle which performs shift determination by using the selected shift stage incorporated by use vehicle speed value, a predetermined time
Calculating a limit value of the acceleration of the vehicle for each interval;
A first vehicle speed value is calculated from the vehicle speed signal of the vehicle speed sensor at every interval, and a second vehicle speed value for a previous shift determination and a limit value of the acceleration are calculated.
A vehicle speed value for comparison is calculated from the first vehicle speed value and the ratio.
Comparing the vehicle speed value of較用, the first vehicle speed value for the comparison
The first vehicle speed value with a second vehicle speed value for this shift determination in the case of less than the vehicle speed value, the first vehicle speed value the ratio
When the vehicle speed is equal to or higher than the vehicle speed for comparison, the vehicle speed for comparison is used as the second vehicle speed for current shift determination, and the shift determination is performed based on the second vehicle speed for current shift determination so as to select a shift stage. control apparatus for a vehicular automatic transmission, characterized in that a control means provided with speed change judging section for. 2. The control device for an automatic transmission for a vehicle according to claim 1, wherein the limit value of the acceleration is equal to or more than an acceleration when the driving wheel is not idling. 3. The control device according to claim 1, wherein the limit value of the acceleration is calculated according to an output shaft output torque of the automatic transmission.