JP3588483B2 - Control method of automatic transmission - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a control method for an automatic transmission such as an automobile, and in particular, when a specific mode switch is operated, a specific mode is set so that a shift to a predetermined gear or less is inhibited to suppress traction by switching to a specific gear. To a method for controlling an automatic transmission.
[0002]
[Prior art]
The gear position of an automatic transmission used for a vehicle or the like is determined in accordance with, for example, a vehicle speed or a throttle valve opening with reference to a shift pattern registered in advance in a control device that controls the automatic transmission. Since the above-mentioned shift pattern is set assuming a general running state, an appropriate speed ratio may not be obtained in an unexpected running state.
[0003]
For example, if a vehicle is to be started on a road surface having a smaller coefficient of friction than a normal road surface such as a snowy road or a muddy road, and if the vehicle is started by selecting the first speed as in the case of starting on a normal road surface, The traction is too large for the frictional force between the vehicle and the road surface, causing wheel spin, and the vehicle cannot start.
[0004]
Therefore, as a conventional technique for solving such a problem, a specific mode (hereinafter, referred to as a snow mode) suitable for the above-described situation, for example, prohibiting switching to the third speed or lower, and a normal mode There is a control method for an automatic transmission in which the automatic transmission is switched by a driver's manual operation. By switching to the snow mode as described above, the traction is reduced by forcibly switching the gear position to the higher gear side, and the vehicle can start.
[0005]
The reason for canceling the snow mode may be a driver's own manual operation or an increase in the temperature of the automatic transmission fluid (ATF) due to an increase in the load on the torque converter caused by the long half-clutch state during starting. When the cancellation of the snow mode is requested due to such factors, the snow mode is unconditionally canceled by the current control method.
[0006]
However, when the snow mode is released from a state in which the vehicle is traveling in the snow mode at a low vehicle speed in the normal mode of, for example, 10 km / h or less, which corresponds to the first speed region, the shift speed is changed to the second gear when the throttle valve opening is large. Immediately switches from third gear to first gear. As a result, traction increases sharply, and the possibility of causing wheel spin exceeding the frictional force between the tire and the road surface increases. Further, in addition to the above-mentioned situation, when the steering angle is large, not only the stability of the vehicle body is lost due to the wheel spin, but also the possibility of causing the vehicle body spin is increased.
[0007]
In order to avoid the above-mentioned dangerous state, for example, a method of permitting release of a specific mode corresponding to a special situation such as a snow mode only when a condition set to avoid the danger is satisfied. Can be considered.
[0008]
Japanese Patent Application Laid-Open No. 3-362 is an example of a prior art relating to a method of controlling an automatic transmission having such a conditional release function of a specific mode. In the related art, when the vehicle is in a traveling state such as an uphill road with a large traveling resistance, the automatic transmission is set to a specific mode suitable for a traveling state in which, for example, overdrive is prohibited. The running resistance is estimated from the throttle valve opening and the vehicle body acceleration. If the vehicle body acceleration is small despite the large throttle valve opening, the running resistance is determined to be large. Release of the specific mode is permitted only when the running resistance is equal to or less than a predetermined value and the vehicle is not turning.
[0009]
As a result, in a vehicle that can obtain relatively large traction by setting to the specific mode, apparent running resistance decreases due to a temporary decrease in the throttle valve opening due to turning, and the apparent running resistance temporarily becomes smaller than a predetermined value. Even if this happens, traction can be maintained by the above-described cancellation condition.
[0010]
[Problems to be solved by the invention]
The above-described conventional technology prevents a specific mode from being released due to a temporary decrease in running resistance due to a temporary turn on an uphill road or the like that requires large traction, thereby preventing traction from being reduced. Therefore, this is completely different from the case in which switching to a predetermined gear or lower is prohibited as in the present case.
[0011]
An object of the present invention is to provide a control method of an automatic transmission that can safely release a specific mode.
[0012]
[Means for Solving the Problems]
According to the present invention, the shift speed of the automatic transmission is switched and controlled in accordance with the vehicle speed and the like, and when a specific mode switch is operated, the specific mode is set and the switching of the shift speed to a predetermined speed or less is prohibited. In the control method of the automatic transmission in which traction is suppressed by
When the steering angle is equal to or larger than a predetermined value obtained in accordance with the opening degree of the throttle valve, the specific mode is prohibited from being released.
In addition, the present invention controls the shift speed of the automatic transmission according to the vehicle speed and the like, and when a specific mode switch is operated, the specific mode is set to switch the shift speed to a predetermined speed or less. In a control method of an automatic transmission in which traction is prohibited to suppress traction,
When the steering angle is equal to or more than a predetermined value obtained in accordance with the intake air pressure, the control method of the automatic transmission is characterized in that the release of the specific mode is prohibited.
Further, the specific mode switch of the present invention is a snow mode switch.
Still further, according to the present invention, when the release operation of the specific mode switch is performed, when the steering angle is equal to or more than the predetermined value, the release is permitted after a state in which the steering angle is less than the predetermined value has elapsed for a predetermined time. It is characterized by the following.
Further, the predetermined time according to the present invention is characterized in that the predetermined time is obtained in accordance with a throttle valve opening.
Still further, the predetermined time according to the present invention is characterized in that the predetermined time is obtained corresponding to the intake air pressure.
In addition, the present invention controls the shift speed of the automatic transmission according to the vehicle speed and the like, and when a specific mode switch is operated, the specific mode is set to switch the shift speed to a predetermined speed or less. In a control method of an automatic transmission in which traction is prohibited to suppress traction,
A method for controlling an automatic transmission, characterized in that, when the release operation of the specific mode switch is performed and the throttle valve opening is equal to or more than a predetermined value, release of the specific mode is prohibited.
Further, the specific mode switch of the present invention is a snow mode switch.
Further, the present invention is characterized in that when the state in which the throttle valve opening is less than a predetermined value continues for a predetermined time, release of the specific mode is permitted.
Still further, the predetermined value according to the present invention is characterized in that the predetermined value is obtained corresponding to the intake air pressure.
Further, the predetermined time according to the present invention is characterized in that the predetermined time is obtained corresponding to the intake air pressure.
[0013]
[Action]
According to the present invention, the gear position of the automatic transmission is switched and controlled in accordance with the vehicle speed and the like, and is operated when the friction coefficient of the road surface such as a snow mode switch is small and traction becomes excessive. When the specific mode switch is operated, the specific mode is set to a specific mode, for example, the shift to a predetermined gear, for example, the second gear or lower, is inhibited, and the traction is suppressed. When the steering angle is equal to or larger than the predetermined value, release of the specific mode is prohibited.
[0014]
Therefore, even if the release of the specific mode is requested during the relatively sharp turning of the steering angle equal to or more than the predetermined value, the specific mode is not released and the gear is not switched to the predetermined stage or less, so that the traction is sharply changed during the turning. Is never too much. Thereby, wheel spin and vehicle spin can be suppressed, and safety can be improved.
Further, since the predetermined value is obtained in accordance with the throttle valve opening or the intake air pressure, the condition for inhibiting the release of the specific mode can be optimally set in accordance with the output of the internal combustion engine.
[0015]
Preferably, when the operation of releasing the specific mode switch is performed, the release of the specific mode is permitted after a predetermined period of time in which the steering angle is less than the predetermined value. Accordingly, even if the specific mode switch is released during turning, the release of the specific mode is permitted after a sufficiently stable traveling state such as a straight-ahead running state is achieved, thereby further improving safety. be able to.
[0017]
Still more preferably, since the predetermined time is obtained in accordance with the throttle valve opening or the intake air pressure, the timing at which the release of the specific mode is permitted can be optimally set in accordance with the output of the internal combustion engine.
[0018]
Further, according to the present invention, the shift speed of the automatic transmission is switched and controlled in accordance with the vehicle speed and the like, and when a specific mode switch such as a snow mode switch is operated, the specific mode is set and a predetermined speed of the shift speed is set. In a control method for an automatic transmission in which traction is suppressed by inhibiting the shift speed, for example, switching to the second speed or lower, the release of the specific mode is prohibited when the throttle valve opening is equal to or greater than a predetermined value.
[0019]
Therefore, when the engine output is a relatively large value, the specific mode is not released even if the release of the specific mode is requested, and the shift speed is not switched to the predetermined speed or less, so that the traction is rapidly increased. Wheel spin and vehicle spin due to the above can be prevented.
[0020]
Preferably, when the release operation of the specific mode is performed, the release of the specific mode is permitted after the state in which the throttle valve opening is less than the predetermined value has elapsed for a predetermined time, so that the output of the internal combustion engine is sufficiently reduced. After that, the gear can be switched to the predetermined gear or lower, and safety can be improved.
[0021]
Still more preferably, since the predetermined value is obtained in accordance with the intake air pressure, the condition for prohibiting the release of the specific mode is optimally set in accordance with the actual output of the internal combustion engine excluding an error due to the influence of altitude and the like. can do.
[0022]
Preferably, the predetermined time is obtained in accordance with the intake air pressure, so that the timing at which the release of the specific mode is permitted can be optimally set in accordance with the output of the internal combustion engine.
[0023]
【Example】
FIG. 1 is a block diagram showing an electrical configuration of a vehicle control device 1 including an automatic transmission control unit 5 according to one embodiment of the present invention. The vehicle control device 1 generally includes an internal combustion engine control unit 3 that controls the internal combustion engine 2 and an automatic transmission control unit 5 that controls the automatic transmission 4.
[0024]
The internal combustion engine control unit 3 roughly determines the fuel injection amount based on the intake air pressure of the internal combustion engine 2 detected by the intake air pressure detector 6, the rotation speed of the internal combustion engine 2 detected by the crank angle detector 7, and the like. Then, the ignition timing is calculated, and the fuel injection valve 8 and the igniter 9 are driven.
[0025]
The internal combustion engine control unit 3 includes input interface circuits 12, 13, 16, and 17, an analog / digital conversion circuit 11, a processing circuit 10 implemented by a microcomputer, and a memory implemented by a read-only memory. 18 and output interface circuits 19 and 20 and the like.
[0026]
An output from the intake air pressure detector 6 is converted into a digital value by an analog / digital conversion circuit 11 and input to a processing circuit 10. The input interface circuit 13 is provided for receiving a signal from the automatic transmission control unit 5 and inputting the signal to the processing circuit 10.
[0027]
The outputs from the neutral switch 14 and the start switch 15 are input to the processing circuit 10 after the waveforms are shaped by the input interface circuits 16 and 17. The neutral switch 14 is turned on when the shift speed of the automatic transmission 4 is parking or neutral. Further, the start switch 15 is turned on during a period in which the starter motor is started.
[0028]
The processing circuit 10 is stored in the memory 18 based on the detection result from the start switch 15, the neutral switch 14, the intake air pressure detector 6, the crank angle detector 7, the signal from the automatic transmission control unit 5, and the like. The fuel injection amount and the ignition timing are calculated with reference to map data and the like, and the opening time of the fuel injection valve 8 is controlled via an output interface circuit 19 realized by a power transistor and the like. The ignition timing and the ignition time of the ignition plug 21 are controlled via the ignition plug 21.
[0029]
The automatic transmission control unit 5 generally includes a throttle valve opening detected by a throttle valve opening detector 22, a rotation speed of a propeller shaft 25 detected by a vehicle speed detector 23, and a shift position detector 24. The solenoid valve 26 of the automatic transmission 4 is selectively driven based on the detected shift position and the like, and the driving force from the internal combustion engine 2 is reduced at a desired reduction ratio and transmitted to the wheels 45.
[0030]
The automatic transmission control unit 5 includes an analog / digital conversion circuit 28, input interface circuits 29, 30, 31, 33, and 35, a processing circuit 27, a memory 36, and output interface circuits 37 and 38. It is comprised including.
[0031]
The throttle valve opening detector 22 is realized by a potentiometer or the like, and the detected throttle valve opening is converted into a digital value by an analog / digital conversion circuit 28, and is processed by a processing circuit 27 realized by a microcomputer or the like. Is entered. The speed pulse detected by the vehicle speed detector 23 is shaped by an input interface circuit 29 and input to a processing circuit 27. The information on the shift position detected by the shift position detector 24 is input to the processing circuit 27 via the input interface circuit 30. Further, the input interface circuit 31 is provided for receiving a signal from the snow mode switch 32 and inputting the signal to the processing circuit 27.
[0032]
The steering angle detector 34 is mounted, for example, on a steering shaft so as to generate a phase difference depending on the rotation direction of the steering shaft, and is provided at a fixed position with two rotating plates having slits formed at equal intervals in the circumferential direction. And an optical sensor comprising a pair of light receiving and emitting elements, wherein the rotation direction and the amount of rotation of the steering shaft are detected by measuring conduction / interruption of an optical path between the light receiving and emitting elements by the rotating plate. I do. Information on the steering angle detected by the steering angle detector 34 is input to the processing circuit 27 via the input interface circuit 33. The input interface circuit 35 is provided for receiving a signal from the internal combustion engine control unit 3 and inputting the signal to the processing circuit 27.
[0033]
The processing circuit 27 performs processing based on the detection results from the shift position detector 24, the vehicle speed detector 23, and the throttle valve opening degree detector 22 based on a shift pattern stored in a memory 36 realized by a read-only memory or the like. The optimum shift speed is read out, and the solenoid valve 26 is switched and controlled via an output interface circuit 38 implemented by a power transistor or the like so that the optimum shift speed is set, thereby switching the shift speed. Further, when it is requested to enter the snow mode by operating the snow mode switch 32, the processing circuit 27 selects a snow mode in which switching to a predetermined gear, for example, the second speed or lower, is prohibited. As a result, traction is suppressed, and the vehicle can be started from a snowy road, for example.
[0034]
Further, when the snow mode switch 32 is operated and the cancellation of the snow mode is requested, the processing circuit 27 further includes a throttle valve opening θ detected by the throttle valve opening detector 22 and a steering angle detector 34. Based on the detected steering angle R and the intake air pressure P input from the output interface circuit 20 of the internal combustion engine control unit 3 via the line 40 and the input interface circuit 35, it is determined whether to cancel the snow mode. Then, the duration t until the snow mode is canceled is calculated. Based on these results, the processing circuit 27 determines whether or not to permit the release of the snow mode. Thus, the snow mode can be continued until the running state such as straight traveling is stabilized.
[0035]
Further, the signal is given from the processing circuit 27 to the input interface circuit 13 of the internal combustion engine control unit 3 via the output interface circuit 37 and the line 39. This signal is a signal indicating the vehicle speed and the shift timing. The internal combustion engine control unit 3 reduces the shift shock, for example, by temporarily delaying the ignition timing in accordance with the shift timing.
[0036]
The control units 3 and 5 are provided with constant voltage circuits 41 and 42, respectively. When the ignition key switch 43 is connected to the IG contact or the ST contact, the constant voltage circuits 41 and 42 are connected to the constant voltage circuits 41 and 42, respectively. Electric power is supplied, and each circuit in each of the control units 3 and 5 is energized.
[0037]
FIG. 2 is a flowchart for explaining the operation when the driver operates the snow mode switch 32. When the snow mode switch 32 is turned on by the driver operating the snow mode switch 32, the process proceeds to step s1. In step s1, it is determined whether or not a snow mode request flag F1 indicating whether or not the snow mode is requested is 1, and if so, in step s2, the snow mode request flag F1 is reset to 0. If not, the process sets the snow mode request flag F1 to 1 in step s3, and ends the process.
[0038]
FIG. 3 is a flowchart for explaining the release operation of the above-mentioned snow mode. This operation is performed, for example, every 3 to 4 msec. In step n1, it is determined whether or not the vehicle is currently running in the snow mode. If so, the process proceeds to step n2. If not, in step n20, it is determined whether or not the snow mode request flag F1 is set to 1. If so, ie, after the snow mode request flag F1 is set to 1 in step s3, the process proceeds to step n21 only at the first processing timing of step n1, and the operation is performed after the snow mode is set. Is terminated, otherwise the operation is terminated directly.
[0039]
In step n2, it is determined whether or not the above-mentioned snow mode request flag F1 is 0. If so, that is, after the snow mode request flag F1 is reset to 0 in step s2, the first step of this step n2 is performed. The process proceeds to step n4 only at the processing timing of the second time, and otherwise proceeds to step n3. In step n3, it is determined whether or not the cancel control flag F2 indicating that the cancel mode has been previously requested but the cancel condition has not been satisfied and the snow mode is forcibly continued and the cancel mode is forcibly continued is 1. Is determined, and if so, the process proceeds to step n4; otherwise, the process ends if the snow mode is continued. In step n4, the throttle valve opening θ input from the throttle valve opening detector 22 via the analog / digital conversion circuit 28 and the steering angle R input from the steering angle detector 34 via the input interface circuit 33. Read.
[0040]
For the steering angle R, a measurement result of the steering angle detector 34 is input to the processing circuit 27 via the input interface circuit 33, for example, every 32 msec. The throttle valve opening θ is obtained by, for example, converting the measurement result of the throttle valve opening detector 22 into a digital value by an analog / digital conversion circuit 28 every 2 msec and inputting the digital value to the processing circuit 27.
[0041]
In step n5, a predetermined value Rc, which is a threshold value of the steering angle R, is calculated using the throttle valve opening θ. Thus, the condition for prohibiting the cancellation of the snow mode can be set in accordance with the output of the internal combustion engine 2. The predetermined value Rc is selected so as to decrease as the throttle valve opening θ increases, and may be stored in the memory 36 in advance as a map or may be calculated. At step n6, it is determined whether or not the steering angle R is equal to or larger than a predetermined value Rc. If so, the process proceeds to step n7, and if not, the process proceeds to step n9. As a result, when the steering angle R is larger than the predetermined value Rc, the operation shifts to a cancel control state in which the release of the snow mode is prohibited.
[0042]
Therefore, in step n7, the cancel control flag F2 is set to 1. As a result, the snow mode is forcibly continued. In step n8, the count value C of the release delay counter for measuring the time during which the cancel control state is continued is reset to 0, and the process ends.
[0043]
On the other hand, in step n6, when the steering angle R is not so large and there is a possibility that the snow mode may be canceled, it is determined in step n9 whether the cancel control flag F2 is 1 or not. If so, the process proceeds to step n10; otherwise, the process proceeds to step n17. In step n10, it is determined whether or not a release delay flag F3 indicating whether the release delay counter is operating is 1 or not. If so, the process proceeds to step n14, otherwise, the delay time is measured. If it is the time to start, the process proceeds to step n11. In step n11, the release delay flag F3 is set to 1. In step n12, a predetermined time t, which is a time for measuring the cancel control state using the above-described throttle valve opening degree θ and is substituted for the count value C of the release delay counter, is calculated. The predetermined time t may be stored in the memory 36 in advance. In step n13, the predetermined time t is substituted for the count value C, and the process ends. Thus, the timing at which the release of the snow mode is permitted can be set according to the output of the internal combustion engine 2.
[0044]
If it is determined in step n10 that the release delay counter has started measuring, the count value C is decremented by one in step n14 and updated. At step n15, it is determined whether or not the count value C is 0. If so, the process proceeds to step n16; otherwise, the process ends. When the steering angle less than the predetermined value Rc corresponding to the throttle valve opening θ continues for the predetermined time t, the cancel control flag F2 is reset to 0 in step n16. In step n17, cancellation of the snow mode is permitted. Further, at step n18, the release delay flag F3 is reset to 0, and the process ends. When the cancel control flag F2 has already been reset to 0 in step n9, that is, when the cancel operation is performed in the straight traveling state, the process proceeds to step n17, and the snow mode is immediately canceled.
[0045]
As described above, in the internal combustion engine control unit 5 according to the present invention, at step n5, the predetermined value Rc is set corresponding to the output of the internal combustion engine 2, so that when the throttle valve opening θ is large and the internal combustion engine output is large, In step n6, it is determined that the snow mode should not be canceled, and in step n7, the snow mode is forcibly continued, so that the shift speed does not switch to a predetermined speed or less, preventing a sudden increase in traction, preventing wheel spin and vehicle spin. , And running stability can be improved.
[0046]
Further, the vehicle is running in the snow mode which is the specific mode, and the cancellation of the snow mode is requested again during the cancel control in which the cancellation of the snow mode is prohibited. In step n6, the steering angle R is changed to the output of the internal combustion engine in step n5. Even if it is determined that the value is equal to or less than the correspondingly optimally set predetermined value Rc, the state elapses in Step n12 for the optimally set predetermined time t corresponding to the internal combustion engine output, and the vehicle travels straight. After the running state is sufficiently stabilized, the snow mode is released in step n17, so that the snow mode can be released safely.
[0047]
FIG. 4 is a flowchart for explaining the operation of another embodiment of the present invention. This embodiment is similar to the above-described embodiment, and corresponding steps are denoted by the same reference numerals.
[0048]
Steps n1 to n3 are the same as those described in FIG. 3. In step n4a, the intake air pressure P input from the output interface circuit 20 of the internal combustion engine control 3 via the line 40 and the input interface circuit 35, and the steering The steering angle R input from the angle detector 34 via the input interface circuit 33 is read. The detection result of the suction air pressure detector 6 is converted into a digital value by an analog / digital conversion circuit 11 every 2 msec, for example, and is input to the processing circuit 10. In step n5a, a predetermined value Rc, which is a threshold value of the steering angle R, is calculated using the intake air pressure P. As a result, the condition for prohibiting the cancellation of the snow mode can be set corresponding to the actual internal combustion engine output excluding the influence of altitude.
[0049]
The operation in steps n6 to n11 is the same as the operation in FIG. 3, and in step n12a, the predetermined time t substituted for the value of the count value C, which is the continuation time of the cancel control state, using the intake air pressure P is set. It is calculated. Thus, the timing at which the release of the snow mode is permitted can be set in accordance with the actual output of the internal combustion engine. The operation in steps n13 to n21 is also the same as the operation in FIG. 3, and cancels the snow mode or cancels the cancellation of the snow mode.
[0050]
FIG. 5 is a flowchart for explaining the operation of still another embodiment of the present invention. This embodiment is similar to the embodiment shown in FIG. 3, and corresponding steps are denoted by the same reference numerals.
[0051]
Steps n1 to n3 are the same as those in FIG. 3 described above. In step n31, the throttle valve opening θ input from the throttle valve opening detector 22 via the analog / digital conversion circuit 28 and the internal combustion engine controller 3 Is read from the output interface circuit 20 through the line 40 and the input interface circuit 35. In step n32, a predetermined value θc which is a threshold value of the throttle valve opening θ is calculated using the intake air pressure P. Thus, the condition for prohibiting the release of the snow mode can be set in accordance with the output of the internal combustion engine. In step n33, it is determined whether or not the throttle valve opening θ is equal to or larger than a predetermined value θc. If so, the process proceeds to step n7, and if not, the process proceeds to step n9. The operation after step n7 is the same as that in FIG. 3, and cancels the snow mode or cancels the cancellation of the snow mode.
[0052]
【The invention's effect】
As described above, according to the present invention, when the specific mode switch is operated, the automatic transmission is set to the specific mode, and the switching of the shift speed to a predetermined shift speed or less is inhibited, and the traction is suppressed. In the control method, when the steering angle is equal to or more than a predetermined value, the release of the specific mode is prohibited, so even if the release of the specific mode is requested during a relatively sharp turn, the release of the specific mode is not permitted, The shift speed is not switched below a predetermined speed. Therefore, it is possible to prevent a sudden increase in traction during turning, prevent vehicle spin or wheel spin, and improve running stability.
Further, since the predetermined value is obtained according to the throttle valve opening or the intake air pressure, the condition for prohibiting the release of the specific mode can be set according to the output of the internal combustion engine. Therefore, when the throttle valve opening or the intake air pressure is small and the output of the internal combustion engine is small, that is, when the traction does not become excessive even when the specific mode is released and the gear is switched to the predetermined gear or lower, the release is permitted. Is done. Thus, the release condition can be set optimally.
[0053]
Preferably, when the release operation of the specific mode switch is performed, the release of the specific mode switch is permitted after the state in which the steering angle is less than the predetermined value has elapsed for a predetermined time, so that the release operation of the specific mode switch is performed during turning. Even if it is performed, the release of the specific mode is permitted only after the traveling state such as straight traveling is sufficiently stabilized, and the specific mode can be released more safely.
[0055]
Preferably, the predetermined time is obtained in accordance with the throttle valve opening or the intake air pressure, so that the timing at which the release of the specific mode is permitted can be optimally set in accordance with the output of the internal combustion engine.
[0056]
Further, according to the present invention, there is provided a control method of an automatic transmission in which when a specific mode switch is operated, a specific mode is set, and switching of the shift speed to a predetermined shift speed or less is inhibited to suppress traction. When the throttle valve opening is equal to or more than a predetermined value, the release of the specific mode is prohibited, so that the output of the internal combustion engine is relatively large, and when the release of the specific mode switches to the predetermined gear position or lower. The release is not permitted in response to the release request of the specific mode, and the shift speed is not switched to a predetermined speed or less. Therefore, since the traction does not increase rapidly, the wheel spin can be suppressed and the stability of the vehicle body can be improved.
[0057]
Preferably, when the release operation of the specific mode is performed, the release of the specific mode is permitted after the state in which the throttle valve opening is less than the predetermined value has passed the predetermined time, so that the output of the internal combustion engine is reduced to the release of the specific mode. Accordingly, the release is prohibited until the traction is reduced to a state where the traction does not become excessive even when the gear is switched to the predetermined gear or lower, and the specific mode can be safely released.
[0058]
Preferably, the predetermined value is obtained in accordance with the intake air pressure, so that the condition for prohibiting the release of the specific mode is optimally set in accordance with the actual internal combustion engine output excluding an error due to the influence of altitude and the like. Can be.
[0059]
Preferably, the predetermined time is obtained in accordance with the intake air pressure, so that the timing for releasing the specific mode can be optimally set in accordance with the output of the internal combustion engine.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an electrical configuration of a vehicle control device 1 including an automatic transmission control unit 5 according to one embodiment of the present invention.
FIG. 2 is a flowchart for explaining an operation when the driver operates a snow mode switch 32;
FIG. 3 is a flowchart illustrating an operation for canceling a snow mode according to an embodiment of the present invention.
FIG. 4 is a flowchart illustrating an operation for releasing a snow mode according to another embodiment of the present invention.
FIG. 5 is a flowchart illustrating a snow mode canceling operation according to still another embodiment of the present invention.
[Explanation of symbols]
1 Vehicle control device
2 Internal combustion engine
3 Internal combustion engine control unit
4 Automatic transmission
5 Automatic transmission control unit
6 Intake air pressure detector
7 Crank angle detector
8 Fuel injection valve
10,27 processing circuit
11,28 analog / digital conversion circuit
14 Neutral switch
15 Start switch
18,36 memory
21 Spark plug
22 Throttle valve opening detector
23 Vehicle speed detector
24 Shift position detector
26 Solenoid valve
32 Snow mode switch
34 Steering angle detector

Claims (11)

In accordance with the vehicle speed, etc., the shift speed of the automatic transmission is controlled to be switched, and when a specific mode switch is operated, the specific mode is set, and switching of the shift speed to a predetermined speed or less is prohibited, and traction is performed. In the control method of the automatic transmission that is suppressed,
When the steering angle is equal to or greater than a predetermined value determined in accordance with the throttle valve opening, the release of the specific mode is prohibited. In accordance with the vehicle speed, etc., the shift speed of the automatic transmission is controlled to be switched, and when a specific mode switch is operated, the specific mode is set, and switching of the shift speed to a predetermined speed or less is prohibited, and traction is performed. In the control method of the automatic transmission that is suppressed,
When the steering angle is equal to or greater than a predetermined value determined in accordance with the intake air pressure, the release of the specific mode is prohibited. 3. The control method for an automatic transmission according to claim 1, wherein the specific mode switch is a snow mode switch. When the release operation of the specific mode switch is performed, when the steering angle is equal to or larger than a predetermined value, the release is permitted after a state in which the steering angle is smaller than the predetermined value has elapsed for a predetermined time. Item 4. The control method for an automatic transmission according to any one of Items 1 to 3. The control method for an automatic transmission according to claim 4, wherein the predetermined time is obtained in accordance with a throttle valve opening. 5. The control method for an automatic transmission according to claim 4, wherein the predetermined time is obtained in accordance with intake air pressure. In accordance with the vehicle speed, etc., the shift speed of the automatic transmission is controlled to be switched, and when a specific mode switch is operated, the specific mode is set, and switching of the shift speed to a predetermined speed or less is prohibited, and traction is performed. In the control method of the automatic transmission that is suppressed,
A method for controlling an automatic transmission, wherein when the release operation of the specific mode switch is performed and the throttle valve opening is equal to or more than a predetermined value, release of the specific mode is prohibited. The method according to claim 7, wherein the specific mode switch is a snow mode switch. 9. The control method for an automatic transmission according to claim 7, wherein the release of the specific mode is permitted when a state in which the throttle valve opening is less than a predetermined value continues for a predetermined time. The control method for an automatic transmission according to any one of claims 7 to 9, wherein the predetermined value is obtained according to an intake air pressure. The control method for an automatic transmission according to claim 9, wherein the predetermined time is obtained according to intake air pressure.

Images