JP3623419B2 - Automatic transmission for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic transmission for a vehicle.
[0002]
[Prior art]
Many commercial vehicles such as trucks are equipped with an automatic transmission. As such an automatic transmission, a mechanical clutch and a gear-type transmission are used, and various sensors for detecting the operation state and actuators for driving these are provided. It is known that a speed change operation of a vehicle is automatically performed as necessary to control the actuator so that the current speed of the transmission matches the target speed at that time (Japanese Patent Laid-Open No. 6-241300). Such). In this case, a function for automatically setting the target stage of the shift control according to the driving state is added regardless of the shift instruction (shift lever operation) of the driver.
[0003]
In such an automatic transmission, the shift timing is automatically determined by a shift map made up of the accelerator opening-engine rotation speed provided for each gear stage (Nissan Diesel Technical Report No. 60 “Electronic Control”). (See “Development of transmission operating device (ESCOT-II, III)”). In addition, there is an apparatus that employs an up-down type shift lever unit (shift instruction means). By simply operating the shift lever to the Up side or Down side, the optimum stage corresponding to the vehicle speed at that time can be controlled. Functions that are automatically set as a target stage (shift instruction stage) are known (Japanese Utility Model Publication No. 6-36356, Japanese Utility Model Publication No. 5-71531).
[0004]
[Problems to be solved by the invention]
By the way, in the driving state where the shift to the target stage according to the driving state is automatically performed regardless of the driver's shift instruction, the foot brake is depressed (accelerator, for example, when the vehicle is decelerated to reaccelerated). When the accelerator is stepped on from a state where the engine is released, the accelerator opening becomes equal to or greater than a certain value (for example, 20%), and the shift is started for the first time. This is especially true in an automatic transmission that uses a mechanical clutch and gear-type transmission. However, there is a problem that the time required for shifting operation (clutch engagement, etc.) is long and re-acceleration is poor.
[0005]
An object of the present invention is to improve such problems.
[0006]
[Means for Solving the Problems]
In the first aspect of the invention, the means for generating the shift control start signal when the current speed of the transmission does not coincide with the target shift speed, and the current speed of the transmission to coincide with the target shift speed when the shift control start signal is received. And a means for detecting a foot brake operation state, and a transition from an operating state of the foot brake to a release state based on the detection signal. And determining means for setting the optimum speed for reacceleration corresponding to the vehicle speed to the target gear position so as to generate a shift control start signal at that time .
[0007]
In the second aspect of the invention, the gear type transmission is connected to the engine via a mechanical clutch, while the clutch actuator that engages and disengages the clutch, the gear shift actuator that drives the gear shift mechanism of the transmission, and the current stage of the transmission is the target speed change. Means for generating a shift control start signal when the gear does not coincide with the gear, and a clutch actuator and a gear shift actuator to perform a gear shift operation so that the current gear position of the transmission matches the target gear when receiving the gear shift control start signal. And a means for detecting the foot brake operation state, and when a transition from the foot brake operating state to the release state is determined based on the detection signal , the shift control is performed at that time. Generated start signal Means for setting the optimum stage of the re-acceleration in accordance with the Rubeku vehicle speed to the target gear position, the providing.
[0008]
【The invention's effect】
In the first and second inventions, when the foot brake is released from the actuated (depressed) state, the optimum stage corresponding to the vehicle speed is set as the target stage of the shift control at that time. When the current gear position does not coincide with the target gear position, the gear shift is started, and the gear shift operation to the optimum gear speed according to the vehicle speed is controlled. Therefore, at the time of re-acceleration after deceleration, the shift start is accelerated by the time required for switching from the foot brake to the axle, so that the re-acceleration performance can be improved.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, 1 is a diesel engine, 2 is a friction clutch, 3 is a synchronous mesh transmission, and the output shaft of the transmission is connected to a rear axle via a propeller shaft (not shown). An electronic governor device 1A for controlling the fuel injection amount is provided in the engine fuel injection pump, a clutch booster 2A for performing the intermittent operation on the clutch 2, and a gear shift unit 3A for performing the gear shift operation on the transmission 3. Reference numeral 27 denotes a supply / exhaust valve of the clutch booster 2A.
[0010]
As detection means necessary for vehicle shift control, an engine rotation sensor 29 that detects the engine speed, an accelerator opening sensor 28 that detects the amount of depression of the accelerator pedal 7 (a required amount of accelerator opening), and a clutch 2 A clutch stroke sensor 22 for detecting a stroke position, a gear position sensor (built in the gear shift unit 3A) for detecting a shift position of the transmission 3, a vehicle speed sensor 21 for detecting a rotational speed from an output shaft of the transmission 3, and a transmission And a gear rotation sensor 23 for detecting the rotation speed of the main gear that idles on the three main shafts.
[0011]
In order to switch between manual control and automatic control of the clutch, clutch switches 24 and 25 for detecting an initial position and an operating position of the clutch pedal are provided. A shift lever unit 4 is provided in the cab as a shift instruction means of the transmission 3 and outputs a shift position signal (shift instruction signal) of the shift lever 4A. The driver's cab also has a display unit 13 for displaying the current stage of the transmission 3 and the like, and a manual shift mode in which the vehicle shift is performed in response to a shift instruction from the driver and an automatic shift that is automatically performed in accordance with the driving state. A switch 31 (automatic shift switch) for selecting a mode and a foot brake switch 26 for detecting depression of a brake pedal (not shown) are provided. 13A is an alarm buzzer.
[0012]
The transmission (T / M) control unit 11 and the engine control unit 12 are responsible for the shift control, and these are connected by serial communication. When the mode switch 31 is in the manual shift mode, when the shift instruction signal of the shift unit 4 is received, the shift is performed when the detection signal of the gear position sensor 33 (current stage of the transmission 3) does not coincide with the shift instruction stage (target stage). A shift request to the instruction stage (shift control start signal) is generated.
[0013]
When the mode switch 31 is in the automatic transmission mode, the target stage is obtained from the detection signal of the accelerator opening sensor 28 and the detection signal of the engine rotation sensor 29, and when the target stage and the current stage of the transmission do not match, the target stage is set. A shift request is generated. When the transition from the foot brake operating state to the released state is determined based on the on / off signal of the brake switch 26, the target stage is obtained from the detection signal of the vehicle speed sensor 21, and the target stage and the current stage of the transmission are determined. When they do not match, a shift request to the target stage is generated.
[0014]
The transmission control unit 11 and the engine control unit 12 are activated by these shift requests, and control the electronic governor device 1A, the clutch booster 2A, and the gear shift unit 3A in order to smoothly perform the shift operation to the target stage at that time. . That is, the engine output is reduced when the shift is started (the control rack of the fuel injection pump is returned), and the clutch disengagement timing is delayed by a predetermined time. If the transmission 3 is not neutral after the clutch is disengaged, the gear is released and then the engine speed is controlled to the target value (target gear rotation). And clutch engagement.
[0015]
In FIG. 2, the transmission control unit 11 is provided with a shift map (a) at the optimum stage according to the vehicle speed, and when the transition to the foot brake release state is determined based on the on / off signal of the brake switch 26. At that time, the optimum stage corresponding to the detection signal of the vehicle speed sensor 21 is obtained from the shift map (a) and automatically set as the target stage of the shift control. Reference numeral 32 denotes an operation switch for an auxiliary brake (exhaust brake, etc.). When the transmission control unit 11 determines that a predetermined condition is satisfied based on a signal from the operation switch 32 and a detection signal from the vehicle speed sensor 21, the engine rotation speed is set. A function to automatically shift down is provided to enhance the braking force such as exhaust brake. Reference numeral 34 denotes a shift control means of the transmission control unit 11, which controls the clutch booster 2A and the gear shift unit 3A.
[0016]
FIG. 3 is a flowchart for explaining the control content of the transmission control unit (processing based on the on / off signal of the brake switch 26), which is repeatedly executed at a predetermined control cycle. In step 1, the signal of the foot brake switch 26 is read. In step 2, it is determined whether or not this brake switch is on (the foot brake is depressed). If this determination is yes, in step 3, the brake ON flag is set (flag = 1).
[0017]
If the determination in step 2 is no, the process jumps to step 4 to determine whether the brake ON flag is set. If this determination is no, the process ends as it is, whereas if yes, the process proceeds to step 5 to step 8. In step 5, the brake ON flag is cleared (flag = 0). In Steps 6 and 7, the detection signal of the vehicle speed sensor 21 is read, and the optimum stage corresponding to the vehicle speed is obtained from the shift map (a) and set as the target stage of the shift control. In step 8, based on the detection signal of the gear position sensor 33, a shift request to the target stage (shift) is made as necessary to match the gear stage (current stage) with the target stage (optimal stage corresponding to the vehicle speed). Control start signal).
[0018]
With such a configuration, when the foot brake is depressed and released from that state, the optimum stage corresponding to the vehicle speed is set as the target stage of the shift control at that time. When they do not coincide with each other, the shift is started, and the shift operation to the optimum stage according to the vehicle speed is controlled. Therefore, at the time of re-acceleration after deceleration, the shift start is accelerated by the time required for switching from the foot brake to the axle, so that the re-acceleration can be improved.
[0019]
For example, when approaching an intersection with the foot brake applied and switching from a red signal to a green signal and reacceleration, the foot brake is started by releasing the foot brake, and from that point on, the vehicle shift operation (engine throttle) Control and clutch engagement / disengagement) is started, and the shifting operation proceeds even during the time of switching to the accelerator, so the time required for the shifting operation is relatively shortened, and the engine output corresponding to the depression angle of the axle is correspondingly reduced. It will be obtained quickly.
[0020]
In particular, in this example (automatic transmission device of a type using a mechanical clutch and a gear type transmission), engine throttle control and clutch engagement / disengagement are also performed for shifting the vehicle, and it takes a certain time to complete the shifting. Therefore, the effect of improving the re-acceleration is great if the shift start is started quickly based on the foot brake release operation without waiting for the accelerator to be depressed. Note that the control content of FIG. 3 is not limited to an automatic transmission device using a mechanical clutch and a gear-type transmission, but can be widely applied to all types of automatic transmissions.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.
FIG. 2 is a functional block diagram showing a part of the control system.
FIG. 3 is a flowchart for explaining the control contents in the same manner.
[Explanation of symbols]
1A Electronic governor device 2A Clutch booster 3A Gear shift unit 4 Shift lever unit 11 Transmission control unit 12 Engine control unit 13 Display unit 21 Vehicle speed sensor 22 Clutch stroke sensor 23 Gear rotation sensor 24, 25 Clutch switch 26 Brake pedal switch 28 Accelerator opening sensor 29 Engine rotation sensor 31 Mode selection switch 33 Gear position sensor

Claims (2)

Means for generating a shift control start signal when the current speed of the transmission does not match the target shift speed, and a shift operation is performed so that the current speed of the transmission matches the target speed when the shift control start signal is received in the automatic transmission of a vehicle including a means for controlling the actuator, and means for detecting a foot brake operation state, when determining the transition to the released state from the operating state of the foot brake on the basis of the detection signal in the time An automatic transmission apparatus for a vehicle, comprising: means for setting an optimum stage for reacceleration corresponding to a vehicle speed as a target gear stage so as to generate a start signal for gearshift control . When a gear-type transmission is connected to the engine via a mechanical clutch, a clutch actuator that engages / disengages the clutch, a gear shift actuator that drives the gear shift mechanism of the transmission, and the current gear position of the transmission does not match the target gear position Means for generating a shift control start signal, and means for controlling the clutch actuator and the gear shift actuator so as to perform a shift operation so as to make the current speed of the transmission coincide with the target speed when the shift control start signal is received. In order to generate a shift control start signal at the time when a transition from the foot brake operating state to the released state is determined based on the detection signal and the means for detecting the foot brake operating state Depending on vehicle speed Automatic transmission for a vehicle, characterized by comprising means, a to set the optimum stage of re-acceleration to the target shift speed has.

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