JP3094579B2 - 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 lever from a neutral position to a forward position or from a neutral position when the vehicle is stopped or traveling at extremely low speed. When the reverse gear position is switched,
The present invention relates to a shift control method.

[0002]

2. Description of the Related Art An automatic transmission for a vehicle which detects a selected position of a shift lever operated by a driver and automatically performs a gear shift operation in accordance with the detected selected position is widely used. ing. When the vehicle equipped with such an automatic transmission is stopped or running at an extremely low speed, the shift lever is moved from the neutral position (N range) to the forward gear position (D range) or in a state where the engine is in the racing state. When a shift operation for switching to the reverse gear position (R range) is performed, the engine driving force rapidly rises. Such a driving operation causes a sudden start or rapid acceleration of the vehicle, so that not only is the driving operation extremely dangerous, but also a problem that excessive torque is applied to the drive shaft. In particular, when the vehicle is at a standstill and a brake device such as a foot brake is operating, if the torque transmission capacity of the input clutch is large, there is a possibility that the drive shaft may be broken.

[0003] The present invention has been made to solve such a problem, and is intended to be used while the vehicle is stopped or traveling at an extremely low speed.
The engine racing condition at
In such a racing state, even if the shift lever is switched from the neutral position to the forward position or the reverse position, the engine driving force does not suddenly rise and the vehicle suddenly starts or accelerates. It is an object of the present invention to provide a shift control method for an automatic transmission for a vehicle, which prevents the occurrence of excessive torque on a drive shaft.

[0004]

In order to achieve the above object, according to the present invention, a selected position of a shift lever operated by a driver is detected, and a shift speed is automatically set in accordance with the detected selected position. In the shift control method for an automatic transmission for a vehicle that performs a shift operation, when it is detected that the shift lever has been switched from a neutral position to a forward position or a reverse position, the vehicle speed , the engine rotation speed, and the engine rotation acceleration are detected. Is detected, the vehicle speed is equal to or lower than a predetermined value, and the detected
The engine speed is higher than the specified value and the engine
A shift control method for an automatic transmission for a vehicle, wherein a shift operation corresponding to a switched switching position is prohibited when a rolling acceleration is equal to or greater than a negative predetermined value .

Another aspect of the present invention is an automatic transmission for a vehicle.
In the shift control method, the shift lever is in the neutral position.
From the forward gear position or the reverse gear position
When detected, the vehicle speed, engine speed and brake
Detecting the operation state of the device, the vehicle speed is below a predetermined value, and
On the other hand, when the detected engine speed is equal to or higher than the predetermined value and the brake device is operating, the shift operation corresponding to the switching position is prohibited.

[0006]

The shift lever is in the neutral position when the vehicle is stopped or the vehicle is traveling at extremely low speed where the vehicle speed is equal to or lower than a predetermined value.
If the detected engine speed is equal to or higher than the predetermined value and the engine
When the rotational acceleration is greater than or equal to the negative predetermined value, or
The shift lever is in the neutral position and the detected engine speed
When the degree is equal to or more than the predetermined value and the brake device is operating, it can be reliably detected from these that the engine is operating in the racing state . In such a case, even if the driver switches the shift lever from the neutral position to the forward position or the reverse position, the shift operation corresponding to the selected switching position is prohibited, so that the sudden increase in the engine driving force is prevented. Prevent rising.

[0007]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an overall structure of an automatic transmission for a vehicle to which the method of the present invention is applied. The automatic transmission is a gear transmission 10 having four forward speeds and one reverse speed, and the gear transmission 10 and an internal combustion engine (not shown). A torque converter 20 interposed between the engine, a differential 30 connected to an output shaft of the gear transmission 10 via a transfer shaft 12 and connected to an axle shaft of a front wheel which is a driving wheel, and a clutch of the gear transmission 10 And brake equipment,
A hydraulic control device 50 for supplying hydraulic oil to the direct coupling mechanism of the torque converter 20; a control signal is output to the hydraulic control device 50 to control a hydraulic pressure supplied to a clutch, a brake device, and the like of the gear transmission 10. An electronic control unit (hereinafter, referred to as an ECU) 40 and the like are provided.

The torque converter 20 is provided with a slip type direct coupling clutch (damper clutch) 26 as a direct coupling mechanism. In addition, the hydraulic control device 50 includes a shift valve whose valve position is switched by a driver's shift operation, a pressure reducing valve that reduces the line pressure from the hydraulic pump according to the vehicle speed, etc., and an operating hydraulic pressure supplied to the torque converter 20. And a damper clutch control valve. Since the configuration of these valves is not particularly limited as long as the method of the present invention can be performed, detailed description of those valves will be omitted.

On the input side of the ECU 40, a turbine speed sensor (Nt sensor) 42 for detecting the speed Nt of the turbine 24 of the torque converter 20, and an N0 sensor 4 for detecting the speed N0 of the transfer shaft (output shaft) 12.
3. Ne sensor 44 for detecting engine speed Ne,
A throttle opening (θt) sensor 4 for detecting a valve opening θt of a throttle valve disposed in the intake passage of the internal combustion engine;
6. An oil temperature sensor 45 for detecting the oil temperature of the hydraulic oil supplied from the hydraulic pump to the hydraulic control device 50, and a brake for outputting an ON signal when a brake pedal (not shown) of the brake device is depressed by the driver. A switch 47, an idle switch 48 for detecting when the throttle valve is closed to the fully closed position and outputting an ON signal, a shift position sensor (inhibitor switch) 49 for detecting a switching position of a shift valve (not shown), etc. Are electrically connected, and detection signals from these sensors are supplied to the ECU 40.

The NO sensor 43 is provided with a transfer shaft driven gear 1 fixed to the transfer shaft 12.
It is attached to the outer periphery of 2a so as to face it. N0
The sensor 43 generates a pulse signal each time each tooth of the gear 12a passes, and calculates the number of revolutions N0 from the time interval of generation of the pulse signal. The rotational speed N0 of the transfer shaft 12 detected by the NO sensor 43 corresponds to the vehicle speed.
The ECU 40 can calculate the vehicle speed from the output shaft speed N0. The switching positions of the shift valve include a parking position (P position), a reverse position (R range), a neutral position (N position), a forward position (D range), a second speed position (2 position), and a first speed position. A position (L position) is provided, and the shift position sensor 49 detects these switching positions selected by the driver switching the shift lever. Further, the engine rotational acceleration can be detected from the difference between the previous value and the current value of the engine rotational speed Ne detected by the Ne sensor 44. The Nt sensor 42 is
Since the turbine rotational speed Nt can be calculated by multiplying the rotational speed N0 of the transfer shaft 12 detected by the NO sensor 43 and the gear ratio of the established gear stage of the gear transmission 10, it is omitted. You can also.

The ECU 40 includes a ROM and a RAM (not shown).
And the like, a central processing unit, an I / O interface, a counter, and the like, and execute shift control and the like according to a control program stored in the storage device. First,
The ECU 40 determines the operating oil temperature detected by the oil temperature sensor 45, the switching position of the shift valve detected by the shift position sensor 49, the rotation speed N0 (vehicle speed) detected by the NO sensor 43, and the throttle valve detected by the throttle opening sensor 46. The optimum gear position is set according to the operating state according to the opening degree θt and the like, and switching control is performed to the set gear position. The details of this switching control are not particularly related to the present invention, and therefore the description thereof is omitted. However, the ECU 40 outputs a control signal to the hydraulic control device 50 in accordance with the set shift speed, and the clutch 40 of the gear transmission 10 described above. And the brake device is supplied with operating oil pressure to control switching to the set gear stage.

Next, according to the shift control method of the present invention, it is assumed that the shift lever is switched from a neutral position to a forward position or a reverse position by the driver while the vehicle is stopped or traveling at an extremely low speed. The details of the shift control procedure are shown in FIGS.
This will be described with reference to flowcharts shown in FIG. 2 and 3 show a shift control procedure according to a first embodiment of the shift control method of the present invention, and the ECU 40 repeatedly executes these routines at a predetermined cycle. First, the ECU 40
In step S10, the switching position of the shift valve detected by the shift position sensor 49 is the neutral position (N position).
Is determined. If the result of this determination is negative (N
o), that is, if this is not the neutral position, the routine is terminated without doing anything. On the other hand, if the determination result is affirmative (Yes), the process proceeds to step S12, where the vehicle speed is calculated from the rotation speed N0 detected by the N0 sensor 43, and the vehicle speed is set to the predetermined value V
It is determined whether it is _H or less. The predetermined value _VH is for determining whether the vehicle is stopped or traveling at an extremely low speed, and is set to an appropriate value (for example, 10 km / hr). The vehicle speed is not a fear that an excessive driving force is generated in the case of larger than this predetermined value V _H, the routine is ended.

If the result of the determination in step S12 is affirmative,
Next, the throttle detected by the throttle opening sensor 46 is
The throttle valve opening θt is read, and the read throttle valve is opened.
Degree θt is a predetermined value T_HDetermine whether the valve is open
(Step S14). Predetermined value T_HIs the engine
It is set to an appropriate value indicating that it is in a constant high load state.
You. If this determination is negative, the engine is racing.
It is determined that it is not in the state, and the routine ends. On the other hand,
If the determination result of step S14 is affirmative, that is, neutral
Shift lever is selected in position and throttle valve is open
Degree θt is a predetermined value T _HIf the valve is open
The engine is in the specified high load condition and the engine is
It is determined that it is in a state. And in this case,
From neutral position to forward gear position (D range) or reverse gear position
To prohibit the shift operation to (R range)
The value 1 is set to the flag FLG, which is a
(Step S16), the routine ends. Like this
From the neutral position to the forward gear position (D range) or the reverse gear position
The operating condition in which shift operation to the shift (R range) should be prohibited
Is determined.

FIG. 3 shows that the shift operation corresponding to the forward position (D range) from the neutral position (N position) or the reverse position (R range) from the neutral position (N position) should or should not be prohibited. Shows the procedure to determine whether to release, ECU
40, first, the driver operates the shift lever to change the selected position from the neutral position (N position) to the forward gear position (D range).
Or whether the vehicle has been switched from the neutral position (N position) to the reverse gear position (R range) (step S2).
0). If this determination is negative, the routine ends without doing anything.

On the other hand, if the determination result in step S20 is affirmative, it is determined whether or not the value 1 is set in the shift operation prohibition flag FLG (step S22). If the flag FLG is not a value of 1, it means that the shift operation is not prohibited. Therefore, after resetting the flag FLG in step S28, the selected forward gear position (D range) or reverse gear position (R range). Is executed (step S30).

The question of the step S22 is affirmative, that is, when the value 1 to the shift operation prohibition flag FLG is set, the process proceeds to step S24, determines whether or not the vehicle speed is greater than the predetermined value V _H I do. Step If the decision result in the S24 is affirmative, it means that the vehicle speed is shifted to a state which is larger than the predetermined value V _H, excessive to the drive shaft running longer shift operation in such a case There is no fear that a large torque will be applied, and the aforementioned steps S28, S30
Is executed to reset the flag FLG and release the prohibition of the shift operation, and then the selected forward gear position (D range),
Alternatively, the shift operation corresponding to the reverse gear position (R range) is executed.

If the result of the determination in step S24 is negative,
Proceeding to step S26, the throttle valve opening is set to the predetermined value _TH.
It is determined whether it is smaller. When the throttle valve opening is shifted to the shorter than that predetermined value T _H From the above state for a predetermined value T _H, the engine is not longer in a predetermined high load state, executing a shift operation to the drive shaft There is no need to worry about excessive torque. In such a case, the above-described steps S28 and S30 are executed to release the prohibition of the shift operation.
A shift operation corresponding to the selected forward position (D range) or reverse position (R range) is executed.

If the result of the determination in step S26 is negative,
That is, the value 1 to the shift operation prohibition flag FLG is set, the vehicle speed is equal to or less than a predetermined value V _H, moreover, when the throttle valve opening is opened above a predetermined value T _H is
The routine ends without executing the above-described step S30. As a result, the shift operation corresponding to the selected forward gear position (D range) or reverse gear position (R range) is not executed.

FIGS. 4 and 5 show a shift control procedure according to a second embodiment of the shift control method of the present invention. The shift control method according to the second embodiment employs the engine speed and the engine speed as parameter values representing the engine load, and the detected engine speed is a predetermined value Nx
If this is the case (the determination result in step S14a is affirmative), and if the engine rotational acceleration is equal to or greater than the negative predetermined value α _E (the determination result in step S14b is affirmative), it is determined that the engine is in a predetermined high load state. Then, the value 1 is set to the shift operation prohibition flag FLG. The flowchart shown in FIG. 4 differs from the flowchart shown in FIG. 2 only in steps S14a and S14b (shown by broken lines in the figure) for determining the load state of the engine. Are denoted by the same reference numerals, and detailed description thereof is omitted.

FIG. 5 is a flow chart for explaining the second embodiment. Step S2 corresponds to steps S14a and S14b of FIG.
6a and 26b are provided, and the remaining steps are the same as the corresponding steps in FIG. Step S26a, 26
In b, instead of the small engine rotational speed is above a predetermined value Nx, and, if smaller than the engine rotational acceleration is a predetermined negative value alpha _E, i.e., the detected engine rotational speed is equal to or higher than a predetermined value Nx (Step S26a Is negative) and the engine rotational acceleration is equal to or more than the negative predetermined value α _E (the determination result in step S26b is negative), the selected forward gear position (D range) or reverse gear position (R The shift operation corresponding to (range) is not executed.

FIGS. 6 and 7 show a shift control procedure according to a third embodiment of the shift control method of the present invention. The shift control method according to the third embodiment employs an engine speed and an operating state of a brake device as parameter values representing an engine load. In this embodiment, a brake switch for detecting the operation state of the brake device is required, but the load state of the engine can be easily determined. This embodiment, the detected engine rotational speed is equal to or higher than a predetermined value N _E (the determination result in the step S14A is affirmative), and the brake switch 48 outputs an ON signal when the brake device is in operation (step S14B
Is positive), it is determined that the engine is in a predetermined high load state, and the value 1 is set to the shift operation prohibition flag FLG. The flowchart shown in FIG. 6 shows steps S14A and S14B for determining the load state of the engine.
Only the part (indicated by a broken line in the figure) is different from the flow chart shown in FIG. 2, and the other steps corresponding to those in FIG.

FIG. 7 is a flow chart for explaining the third embodiment. Step S2 corresponds to steps S14A and 14B for judging the load state of the engine shown in FIG.
6A and 26B are provided, and the remaining steps are the same as the corresponding steps in FIG. Step S26A, 26
In B, the engine speed is not smaller than the predetermined value Nx and the brake device is not in the inoperative state, that is, the detected engine speed is equal to or higher than the predetermined value Nx (the determination result in step S26A is negative). ) And when the brake device is operating (the determination result in step S26B is negative), the selected forward gear position (D range);
Alternatively, the speed change operation corresponding to the reverse gear position (R range) is not executed.

In the third embodiment, the brake device may be a foot brake, a parking brake or the like. As a modified example of the third embodiment, when the idle switch 48 is off and the brake device is operating, that is, when the throttle valve is opened while the brake pedal is depressed, the engine is in a predetermined high load state. May be determined.

[0024]

As is apparent from the above description, according to the shift control method for an automatic transmission for a vehicle of the present invention, the shift lever is switched from the neutral position to the forward position or the reverse position. when the detected vehicle speed is equal to or less than the predetermined value, and is the engine rotational speed is higher than a predetermined value,且
When the engine rotational acceleration is equal to or greater than the negative predetermined value,
Or, if the vehicle speed is lower than a predetermined value and the detected error
The engine speed is higher than the specified value and the brake
When the vehicle is operating, the shift operation corresponding to the switched position is prohibited, so that the vehicle is stopped or running at an extremely low speed, and the engine is in the racing state. Even when the shift lever is switched from the neutral position to the forward gear position or the reverse gear position, sudden start and sudden acceleration of the vehicle can be prevented, and excessive torque on the drive shaft is prevented. can do.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of an automatic transmission to which a shift control method according to the present invention is applied.

FIG. 2 shows a shift control procedure according to a first embodiment of the shift control method of the present invention, which determines a driving state in which a shift operation corresponding to a forward position from a neutral position or a reverse position from a neutral position is to be prohibited. It is a flowchart for performing.

FIG. 3 is a flowchart for inhibiting a shift operation or canceling the inhibition in the first embodiment of the shift control method of the present invention.

FIG. 4 shows a shift control procedure according to a second embodiment of the shift control method of the present invention, and determines a driving state in which a shift operation corresponding to a forward position from a neutral position or a reverse position from a neutral position is to be prohibited. It is a flowchart for performing.

FIG. 5 is a flowchart for inhibiting a shift operation or canceling the inhibition in a second embodiment of the shift control method of the present invention.

FIG. 6 shows a shift control procedure according to a third embodiment of the shift control method of the present invention, and determines an operation state in which a shift operation corresponding to a forward position from a neutral position or a reverse position from a neutral position is to be prohibited. It is a flowchart for performing.

FIG. 7 is a flowchart for inhibiting a shift operation or canceling the inhibition in the third embodiment of the shift control method of the present invention.

[Explanation of symbols]

 Reference Signs List 10 gear transmission 12 transfer shaft 20 torque converter 40 electronic control unit (ECU) 42 turbine speed (Nt) sensor 43 N0 sensor 44 engine speed (Ne) sensor 46 throttle opening (θt) sensor 47 brake switch 48 idle switch 49 shift position sensor 50 hydraulic control device

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI F16H 59:54 63:12 (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (2)

(57) [Claims] In a shift control method for an automatic transmission for a vehicle, a shift position of a shift lever operated by a driver is detected, and a shift speed is automatically changed according to the detected selected position. when detecting that it has been switched to the forward gear position or reverse gear position from the position, speed, et
The engine speed and the engine speed are detected, and the vehicle speed is equal to or less than a predetermined value, and the detected engine speed is detected.
Degree is greater than or equal to a predetermined value and the engine rotational acceleration is negative.
A shift control method for an automatic transmission for a vehicle, wherein the shift operation corresponding to the switched position is prohibited when the shift value is equal to or greater than a predetermined value . 2. A position for selecting a shift lever operated by a driver.
The gear position is detected and the gear position is automatically set according to the selected position.
The shift control method of an automatic transmission for a vehicle that performs a shift operation
And the shift lever is moved from the neutral position to the forward
When it is detected that the gear has been shifted to the gear position,
Detects engine rotation speed and brake device operation status
The vehicle speed is lower than a predetermined value and the detected engine
If the rotation speed is higher than the specified value and the brake
When moving, the change corresponding to the switched switching position
A shift control method for an automatic transmission for a vehicle , wherein a speed operation is prohibited .