JP2010121709A - Control device of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of an automatic transmission capable of reducing a sense of incongruity of a driver caused by frequently repeating execution and interruption of low μ road starting processing, in a control device of the automatic transmission for executing the low μ road starting processing. <P>SOLUTION: An electronic control device sets a starting shift stage of the automatic transmission to a second speed by executing the low μ road starting processing on condition of determining a low μ road when a vehicle travels on the low μ road. The electronic control device continues the low μ road starting processing (Step S240) when an ignition switch is not operated for OFF after starting the low μ road starting processing (Step S220: NO). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for an automatic transmission for a vehicle.

In the automatic transmission mounted on the vehicle, the shift speed from the first speed to the highest speed is appropriately set according to the operation amount of the accelerator pedal, the vehicle speed, and the like.
On the other hand, on a low μ road where the friction coefficient of the road surface is low, an automatic shift that performs a so-called low μ road start process is set, for example, as a low μ road shift characteristic, the start speed is set to, for example, two speeds higher than the first speed normally used A machine control device is known (for example, Patent Document 1).

When braking the vehicle while traveling on a low μ road, the driven wheel may lock before the driving wheel. This is because the driving wheel at the time of braking is given a driving force due to the creep phenomenon even when the accelerator pedal is not operated, so that the braking force against the driving wheel is relative to the driving force due to the creep phenomenon. This is because the driven wheel is locked before the driving wheel is locked. As described above, when the driven wheel is locked or the braking force of the driving wheel is reduced, the stopping performance of the vehicle is deteriorated, for example, the braking distance becomes longer or the posture of the vehicle becomes unstable during braking. It becomes like this. In order to avoid such a problem, a low μ road start process as in Patent Document 1 is performed.
JP-A-8-121484

  By the way, if such a low μ road start process is interrupted due to some factor, the previous 2nd speed start returns to the normal 1st speed start, but if the low μ road determination is made, the low μ road start process is performed again. It becomes like this. If the low μ road start process is performed or not performed as described above, the start / stop characteristics of the vehicle are different from time to time, resulting in an uncomfortable feeling to the driver.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device for an automatic transmission that performs low μ road start processing, and that execution and interruption of low μ road start processing are frequently repeated. An object of the present invention is to provide a control device for an automatic transmission that can reduce the driver's uncomfortable feeling.

In the following, means for achieving the above object and its effects are described.
The invention according to claim 1 automatically executes a low μ road start process for setting a start gear ratio of an automatic transmission mounted on a vehicle to a high gear ratio higher than the minimum gear ratio when traveling on a low μ road. The gist of the control device for an automatic transmission is to continue the low μ road start process from the start of the low μ road start process until the engine is stopped.

  According to the above configuration, once the low μ road start process is started, the low μ road start process is continuously performed until the engine operation is stopped. Therefore, unlike the case where the low μ road start process is terminated when the shift stage is shifted up to the second speed or higher, for example, the start mode on the low μ road is always kept constant during one trip. It becomes like this. For this reason, it is possible to suppress that the start / stop characteristics of the vehicle become different each time when the low μ road start process is performed or not performed, thereby causing the driver to feel uncomfortable. become able to.

  According to a second aspect of the present invention, in the control device for an automatic transmission according to the first aspect, the low μ road start process is forcibly terminated on condition that the required driving force of the vehicle is equal to or greater than a predetermined driving force. This is the gist.

  According to the above configuration, when the required driving force of the vehicle is equal to or higher than the predetermined driving force, such as when the vehicle needs to travel on a step on the road surface, the low μ road start process is forcibly terminated. It is done. Since the low μ road start process is stopped in this way, the shift stage of the automatic transmission can be changed to the first speed where more driving force can be obtained, and it is necessary for the vehicle to travel on a step on the road surface. Even if there is, it will be possible to ride over this.

  As described in claim 2, when it is determined that the required driving force of the vehicle is equal to or greater than a predetermined driving force, the accelerator operation amount by the driver is equal to or greater than a predetermined amount, as in the invention according to claim 3. It can be determined based on the fact that

Hereinafter, an embodiment of a control device for an automatic transmission according to the present invention will be described with reference to FIGS.
FIG. 1 shows the overall configuration of a vehicle equipped with the automatic transmission control device of this embodiment.

  As shown in FIG. 1, an engine 10 as a power source is mounted on a vehicle 100, and a throttle valve 12 that adjusts an intake air amount is provided in an intake passage 11 of the engine 10. . In the engine 10, the engine output is adjusted by supplying fuel corresponding to the intake air amount from the fuel injection valve.

  The crankshaft of the engine 10 is connected to the input shaft of the torque converter 20 that is a fluid coupling. The output shaft of the torque converter 20 is connected to the input shaft of the automatic transmission 30 having a plurality of shift stages. The output shaft of the automatic transmission 30 is connected to the propeller shaft 40 and is connected to the differential gear 50 via the propeller shaft 40. The output shaft of the differential gear 50 is connected to the right rear wheel 70RR and the left rear wheel 70RL of the vehicle 100, respectively. As described above, the vehicle 100 is a rear wheel drive vehicle including the automatic transmission 30. Further, a brake 80 is provided on each of the right front wheel 60FR, the left front wheel 60FL, the right rear wheel 70RR, and the left rear wheel 70RL of the vehicle 100.

  A shift lever device 31 that selects the gear position of the automatic transmission 30 is provided in the vehicle interior of the vehicle 100. The shift lever device 31 is provided with shift positions such as “P (parking)”, “R (reverse)”, “N (neutral)”, and “D (drive)”. From the shift lever device 31, the operation position of the shift lever is output as a shift position signal.

  For example, at the shift position “D”, the gear position of the automatic transmission 30 is automatically selected from the first gear to the highest gear (for example, sixth gear) according to the shift schedule based on the operation amount of the accelerator pedal, the vehicle speed, and the like. Is done. The operation positions of the shift levers such as “P”, “R”, “N”, and “D” are displayed on a shift indicator 91 provided in the meter panel 90 of the driver's seat.

  The state of the vehicle 100, the driver's request, and the like are detected by various sensors. For example, the engine speed NE is detected by the crank angle sensor 300. Furthermore, the intake air amount sensor 310 detects the intake air amount GA. Further, a throttle opening degree TA, which is the opening degree of the throttle valve 12, is detected by the throttle opening degree sensor 320. The coolant temperature THW of the engine 10 is detected by the water temperature sensor 330, and the vehicle speed SP of the vehicle 100 is detected by the vehicle speed sensor 340. An accelerator operation amount ACCP, which is an operation amount of the accelerator pedal, is detected by the accelerator sensor 350, and whether or not the brake pedal is depressed by the driver of the vehicle 100 is detected by the brake sensor 360. The acceleration G of the vehicle 100 is detected by the acceleration sensor 370, and the yaw rate (rotational angular velocity in the turning direction of the vehicle 100) YR is detected by the yaw rate sensor 380. In addition, a steering operation amount STE that is an operation amount of the steering wheel by the driver of the vehicle 100 is detected by the steering sensor 390. By the right front wheel sensor 400, the left front wheel sensor 410, the right rear wheel sensor 420, and the left rear wheel sensor 430, the right front wheel speed SPFR that is the wheel speed of the right front wheel 60FR, the left front wheel speed SPFL that is the wheel speed of the left front wheel 60FL, A right rear wheel speed SPRR that is the wheel speed of the right rear wheel 70RR and a left rear wheel speed SPRL that is the wheel speed of the left rear wheel 70RL are detected.

  In addition, signals from the various sensors described above are input to the electronic control device 200. The electronic control unit 200 controls the vehicle 100 based on signals input from various sensors, for example, various engine controls such as fuel injection control and ignition timing control of the engine 10, and shift control of the automatic transmission 30. Etc.

  By the way, when braking the vehicle while traveling on a low μ road having a low friction coefficient on the road surface, the driven wheel may be locked before the driving wheel. Even when the accelerator pedal is not operated, a driving force due to a creep phenomenon is applied to the driving wheels during braking. Therefore, the braking force on the driving wheel is relatively reduced by the amount of the driving force due to the creep phenomenon, and as a result, the driven wheel is locked before the driving wheel is locked. As described above, when the driven wheel is locked or the braking force of the driving wheel is reduced, the stopping performance of the vehicle is deteriorated, for example, the braking distance becomes longer or the posture of the vehicle becomes unstable during braking. It becomes like this.

  In order to avoid such a problem, in addition to the various controls described above, the electronic control unit 200 executes a low μ road start process for starting the vehicle 100 at the second speed when it is determined that the road surface is a low μ road. I have to.

  In addition, if such a low μ road start process is interrupted for some reason, the low μ road start process is executed, for example, a low μ road determination is made, although the previous 2nd speed start returns to the normal 1st speed start. When is established, the low μ road start process is performed again. If the low μ road start process is performed or not performed as described above, the start / stop characteristics of the vehicle are different from time to time, resulting in an uncomfortable feeling to the driver.

  Therefore, in the electronic control apparatus 200 of the present embodiment, once the low μ road start process is started, the low μ road start process is continuously performed until the operation of the engine 10 is stopped. Such a low μ road start process will be described in detail below with reference to FIGS. 2 and 3.

FIG. 2 is a flowchart showing a processing procedure of low μ road start execution processing. This process is repeatedly executed by the electronic control device 200 at predetermined intervals.
When this process is started, it is first determined whether or not the low μ road start process is being executed as shown in FIG. 2 (step S110). If it is determined that the low μ road start process is already being executed (step S110: YES), this process is temporarily terminated.

  On the other hand, when it is determined that the low μ road start process has not been executed (step S110: NO), it is determined whether or not an execution condition for the low μ road start process is satisfied (step S120). Here, as an execution condition of the low μ road start process, for example, a low μ road determination is made.

  Here, a determination method for determining the low μ road will be described. First, the electronic control unit 200 constantly calculates the rotational speed difference between the front wheels and the rear wheels based on the right front wheel speed SPFR, the left front wheel speed SPFL, the right rear wheel speed SPRR, and the left rear wheel speed SPRL, which are the wheel speeds of the vehicle 100. Then, the wheel slip ratio is calculated based on the rotational speed difference. When the slip ratio exceeds a threshold value when the vehicle 100 starts or accelerates, the road surface is a low μ road, that is, driving wheels such as the right rear wheel 70RR and the left rear wheel 70RL are excessively driven. It is judged that it is slipping by force. In this process, if it is determined that the execution condition for the low μ road start process is satisfied (step S120: YES), the low μ road start process is executed (step S130). Therefore, even when there is a request for shifting to the first speed, shifting to the first speed is not performed, and the gear position of the automatic transmission 30 is set to the second speed. Further, when the shift stage of the automatic transmission 30 is set to the first speed, the gear is forcibly shifted up to the second speed.

On the other hand, if it is determined that the execution condition for the low μ road start process is not satisfied (step S120: NO), the process is temporarily terminated without executing the low μ road start process.
In addition to such low μ road start execution processing, in the present embodiment, low μ road start permission determination processing for determining whether or not to continue execution of the low μ road start processing is executed. FIG. 3 shows a processing procedure of the low μ road start possibility determination process. This process is also repeatedly executed at predetermined intervals by the electronic control device 200.

  As shown in FIG. 3, in this process, it is first determined whether or not the low μ road start process is being executed (step S210). Here, if it is determined that the low μ road start process has not been executed (step S210: NO), this process is once terminated.

  On the other hand, if it is determined that the low μ road start process is being executed (step S210: YES), it is determined whether or not the ignition switch is turned off by the driver of the vehicle 100 (step S220). When it is determined that the ignition switch has been turned off (step S220: YES), the low μ road start process is terminated (step S250), assuming that the operation of the engine 10 has been stopped, and this process is temporarily performed. Is terminated.

  If it is determined that the ignition switch is not turned off (step S220: NO), it is determined whether or not the accelerator operation amount ACCP by the driver of the vehicle 100 is greater than or equal to a predetermined amount ACCPD (step S230). .

  Here, the accelerator operation amount ACCP corresponds to the required driving force of the vehicle 100, and when the accelerator operation amount ACCP is equal to or greater than the predetermined amount ACCPD, it is determined that the required drive force of the vehicle 100 is equal to or greater than the predetermined drive force. . Moreover, as a case where the accelerator operation amount becomes equal to or greater than the predetermined amount ACCPD, for example, there is a case where the vehicle 100 needs to travel on a step on the road surface. That is, the predetermined amount ACCPD is a value determined to require a larger driving force corresponding to the first speed, and is a value set based on an experiment or the like.

  In this process, when it is determined that the accelerator operation amount ACCP is less than the predetermined amount ACCPD (step S230: NO), the execution of the low μ road start process is continued (step S240), and the process is temporarily terminated. Is done. Thus, in the present embodiment, when the ignition switch is not turned off (step S220: NO) and the accelerator operation amount ACCP is less than the predetermined amount ACCPD (step S230: NO), the low μ road start process is performed. Execution continues.

  On the other hand, when it is determined that the accelerator operation amount ACCP is equal to or larger than the predetermined amount ACCPD (step S230: YES), the execution of the low μ road start process is temporarily forcibly terminated (step S260). The completion of the low μ road start process is continued until the accelerator operation amount ACCP becomes “0” (step S270: NO). It is assumed that the accelerator operation by the driver of vehicle 100 is released when the accelerator operation amount is “0”.

  When it is determined that the accelerator operation amount ACCP is “0” (step S270: YES), the execution of the low μ road start process is resumed (step S280), and this process is temporarily terminated.

According to the embodiment described above, the following effects can be obtained.
(1) Once the low μ road start process is started, the low μ road start process is continuously performed until the operation of the engine 10 is stopped. Therefore, unlike the case where the low μ road start process is terminated when the shift stage is shifted up to the second speed or higher, for example, the start mode on the low μ road is always kept constant during one trip. It becomes like this. For this reason, it is possible to suppress that the start / stop characteristics of the vehicle become different each time when the low μ road start process is performed or not performed, thereby causing the driver to feel uncomfortable. become able to.

  (2) When the required driving force of the vehicle 100 is greater than or equal to a predetermined driving force, such as when the vehicle 100 needs to ride on a step on the road surface, the low μ road start process is forcibly terminated. . Since the low μ road start process is thus stopped, the shift stage of the automatic transmission 30 can be changed to a first speed that can provide more driving force, and the vehicle travels on a step on the road surface. Even when it is necessary, it is possible to ride over this.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above embodiment, when the accelerator operation amount ACCP becomes “0”, it is considered that the accelerator operation by the driver of the vehicle 100 has been released (step S270). In addition, for example, the accelerator operation may be regarded as being released when the accelerator operation amount becomes a very small value that approximates “0”.

  In the above embodiment, in the process shown in FIG. 3, the process of determining whether or not the driving force of the vehicle 100 is more necessary (step S230), and the driving force of the vehicle 100 is requested. The process (step S270) for determining whether or not the vehicle is released is determined based on the accelerator operation amount ACCP by the driver of the vehicle 100. In addition, for example, the vehicle driving force is determined based on the driving mode of a member that is driven in accordance with the required driving force of the vehicle, such as the speed of the accelerator operation by the driver of the vehicle and the opening of the throttle valve. You may do it. However, even when determining the driving force of the vehicle based on values other than the accelerator operation amount ACCP, such as the accelerator operating speed and the throttle valve opening, a predetermined value that determines that the driving force of the vehicle is more required (A value corresponding to the predetermined amount ACCPD in the above step S230) and a predetermined value (a value corresponding to “0” in the above step S270) determined that the request for the driving force of the vehicle is cancelled are required. There is.

  In the above embodiment, when it is determined that a larger driving force of the vehicle 100 is required (step S230 in FIG. 3: YES), the execution of the low μ road start process is temporarily terminated, and the vehicle 100 When it is determined that the request for driving force is released (step S270: YES), the execution of the low μ road start process is resumed. In addition, if it is determined that a larger driving force of the vehicle is required, the low μ road start process is resumed when a predetermined time has elapsed regardless of whether the request is canceled or not. May be.

  In the above embodiment, the low μ road determination is performed by calculating the wheel slip ratio based on the difference between the rotational speeds of the front and rear wheels of the vehicle 100, and the road surface is low μ road when the slip ratio exceeds a threshold value. It was determined to be. The determination method of the low μ road is not limited to this. For example, a method is adopted in which a sensor is provided in the wheel to detect the vibration amount of the wheel and to determine whether the road is a low μ road from the vibration amount of the wheel. May be.

  In the above embodiment, the end of execution of the low μ road start process is made on condition that the ignition switch is turned off or the accelerator operation amount ACCP is equal to or greater than the predetermined amount ACCPD. The condition may be that the ignition switch is turned off only.

  The present invention can be similarly applied to a front wheel drive vehicle and a four wheel drive vehicle. Further, the present invention can be applied not only to a stepped transmission but also to a vehicle equipped with a continuously variable transmission.

1 is a schematic diagram showing a configuration of a vehicle to which the control device according to the present invention is embodied and to which the control device is applied. 6 is a flowchart showing a processing procedure of low μ road start execution processing according to the embodiment; 9 is a flowchart showing a processing procedure of low μ road start permission determination processing according to the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Intake passage, 12 ... Throttle valve, 20 ... Torque converter, 30 ... Automatic transmission, 31 ... Shift lever device, 40 ... Propeller shaft, 50 ... Differential gear, 60FL ... Left front wheel, 60FR ... Right front wheel , 70RL ... left rear wheel, 70RR ... right rear wheel, 80 ... brake, 90 ... meter panel, 91 ... shift indicator, 100 ... vehicle, 200 ... electronic control unit, 300 ... crank angle sensor, 310 ... intake air amount sensor, 320 ... throttle opening sensor, 330 ... water temperature sensor, 340 ... vehicle speed sensor, 350 ... accelerator sensor, 360 ... brake sensor, 370 ... acceleration sensor, 380 ... yaw rate sensor, 390 ... steering sensor, 400 ... right front wheel sensor, 410 ... Left front wheel sensor, 420 ... right rear wheel sensor, 430 ... left Wheel sensor.

Claims (3)

In a control device for an automatic transmission that automatically executes a low μ road start process for setting a start gear ratio of an automatic transmission mounted on a vehicle when traveling on a low μ road to a high gear ratio higher than a minimum gear ratio,
The automatic transmission control device, wherein the low μ road start process is continued from the start of the low μ road start process until the operation of the engine is stopped. The control apparatus for an automatic transmission according to claim 1,
The control apparatus for an automatic transmission, wherein the low μ road start process is forcibly terminated on condition that the required driving force of the vehicle is equal to or greater than a predetermined driving force. The control apparatus for an automatic transmission according to claim 2,
A control device for an automatic transmission, characterized in that, when an accelerator operation amount by a driver of the vehicle becomes a predetermined amount or more, it is determined that a required driving force of the vehicle becomes a predetermined driving force or more.

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