JPH0453485Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Fields This invention relates to automatic transmission, especially calculating the appropriate gear position and automatically adjusting the gear position to the gear position obtained by this calculation. The present invention relates to an automatic transmission in which the gear position is changed by an actuator, and furthermore, it is used in an automatic transmission in which a mechanical clutch and a gear transmission are controlled by a microcomputer to perform automatic gear shifting operations. Concerning what is suitable.

〓Summary of the invention〓 The present invention is designed to reduce the number of engine revolutions when the engine speed exceeds a predetermined speed even when the vehicle changes to a state where it crosses the downshift line for switching to the starting gear when driving at low speed. The vehicle does not switch to the starting gear, but continues to travel in the higher gear position, thereby improving fuel efficiency.

<Prior Art> Automatic transmissions have been proposed to omit the driver's complicated gear shifting operations. In this automatic transmission, a calculation means such as a microcomputer selects the gear to be used depending on the vehicle speed, accelerator opening, etc., and the actuator meshes the selected gear to automatically set a predetermined gear ratio. It was designed to obtain By automatically installing such an automatic transmission, there is almost no need for the driver to operate a lever to change gears. As a prior art related to the present invention, there is, for example, Japanese Unexamined Patent Publication No. 127559/1983, but there is no description regarding the gist of the present invention.

〓Problems to be solved by the invention〓 In such an automatic transmission, the microcomputer for controlling it always refers to the speed change map according to the driving condition of the vehicle. When the shift-up line is crossed, an upshift operation is automatically performed, and when the shift-down line is crossed, a downshift operation is automatically performed. Therefore, when the vehicle is decelerated to gradually reduce its speed, the downshift line is sequentially crossed, and when the accelerator pedal is depressed, a corresponding downshift operation is performed. When the vehicle speed drops below a predetermined speed, the gear is automatically switched to the starting gear.

However, during normal low-speed driving, as long as the vehicle is not stopped, it is possible to continue driving the vehicle by gently accelerating in the higher gear position without changing to the starting gear. Therefore, if the automatic transmission automatically switches to the starting gear in the above case, not only will the downshift operation be performed unnecessarily,
This has the disadvantage of worsening fuel efficiency.

The present invention was developed in view of these problems, and is an automatic transmission that eliminates unnecessary shifting to a starting gear when driving at low speeds, thereby reducing fuel consumption. The purpose is to provide the following.

〓Means for solving the problem〓 As shown in Fig. 1, the present invention calculates the appropriate gear position and automatically controls the actuator to reach the value obtained by this calculation. In the transmission, the transmission is configured to change the gear position by changing the gear position, a shift actuator and a select actuator for selecting the gear position, and a clutch actuator for switching the clutch to a disengaged state when changing the gear position. , When the vehicle is traveling at a predetermined speed or less and the engine speed is above the predetermined speed even if the vehicle changes to a state where it crosses the downshift line for switching to the starting gear, the accelerator pedal is not pressed. The present invention relates to an automatic transmission characterized in that it is provided with means for preventing switching to the starting gear when the starting gear is not fully depressed.

〓Effect〓 Therefore, even when the vehicle is traveling at a predetermined speed or lower and the state changes to a state where the downshift line for switching to the starting gear is changed, if the engine rotation speed is higher than the predetermined rotation speed. If the accelerator pedal is not fully depressed, the shift to the starting gear is not performed. Therefore, from this, it becomes possible to continue traveling by performing gentle acceleration in the upper gear position, and it becomes possible to improve fuel efficiency.

〓Example〓 The present invention will be described below with reference to an illustrated example.
FIG. 2 shows an engine for an automobile equipped with an automatic transmission according to an embodiment of the present invention. Fuel is supplied to each cylinder sequentially. The fuel injection pump 11 is a timer 12
It is designed to be driven by an engine 10 via a timer 12, and the timing of fuel injection is adjusted by this timer 12. Furthermore, the fuel injection pump 11 is equipped with a governor 13, and the governor 13 is adapted to adjust the amount of fuel to be injected.

A flywheel housing 14 is provided on the rear side of the engine 10, and this housing 1
A flywheel fixed to the end of the crankshaft is housed within the crankshaft. And on the back side of this flywheel is clutch 3.
0 is provided, and the flywheel housing 14 is connected to the clutch 30.
A transmission 15 is attached to the rear side of the . This transmission 15 is configured to change the rotational speed of the engine 10 to a predetermined value and transmit it to the drive wheels via a propeller shaft 16.

The transmission 15 constitutes an automatic transmission, and a shift actuator 17 and a selection actuator 18 are provided above the transmission. Furthermore, clutch 3 is attached to the back side of the flywheel.
A clutch actuator 19 for controlling the connection and disconnection of the transmission 15 is mounted on the outer side of the casing of the transmission 15. Furthermore, a fuel control actuator 20 is provided at the front end of the fuel injection pump 11 to adjust the position of the control rack and control the amount of fuel supplied. These four actuators 17,1
8, 19, and 20 are each driven by a driving means based on instructions from a microcomputer 21.

The input side of the microcomputer 21 is connected to a control box 22. This control box 22 is the gear shift lever 2.
It has 3. Furthermore, this microcomputer 21 is connected to an accelerator sensor 25 that detects the opening degree of the accelerator or the amount of depression of the accelerator pedal 24. Further, the microcomputer 21 is connected to a vehicle speed sensor 26, an engine rotation sensor 27, a rack sensor 28, a clutch sensor 29, and a gear position sensor 31, respectively.

The vehicle speed sensor 26 is provided on the side of the transmission 15.
The vehicle speed is detected based on the rotational speed on the output side of the engine. Further, the engine rotation sensor 27 is attached to the front side of the engine 10 and is adapted to detect the rotation speed of the engine 10. Furthermore, the rack sensor 28 is connected to the actuator 20.
It is attached to the tip side of the fuel injection pump 1.
The position of the control rack No. 1 is detected. Further, the clutch sensor 29 is attached to the distal end side of the clutch actuator 19, and is adapted to detect the connected and disconnected states of the clutch 30. Further, a gear position sensor 31 is provided on the upper part of the transmission 15, and is adapted to detect the gear position.

Next, the operation of this automatic transmission configured as described above will be explained. This operation is performed based on a program preset in the microcomputer 21.
When the shift lever 23 of the control box 22 is at the automatic shift position, the shift operation is automatically performed. On the other hand, when the shift lever 23 is in the manual position, a manually selected shift operation is performed via the actuators 17 and 18.

To give an overview of the automatic gear shifting operation, the microcomputer 21 detects whether the gear shift lever 23 of the control box 22 is in the automatic gear shifting position, and if it is in the automatic gear shifting position, the microcomputer 21 detects whether or not the gear shift lever 23 of the control box 22 is in the automatic gear shifting position. The amount of depression or the opening degree of the accelerator and the vehicle speed are read from the accelerator sensor 25 and the vehicle speed sensor 26, respectively.
Further, the microcomputer 21 reads the map stored in its memory, and based on this map, calculates whether automatic gear shifting is possible. And if automatic gear shifting is possible,
A speed change operation is performed to obtain the calculated gear ratio. On the other hand, if it is determined that automatic gear shifting is not possible, no gear shifting operation is performed.

The specific operation of automatic gear shifting is such that the shift actuator 17 and the selection actuator 18 are operated based on a command from the microcomputer 21 via a drive means (not shown), and the gears of the transmission 15 are selected. The selected gears of the transmission 15 are thereby brought into mesh. Therefore, a predetermined gear ratio can be obtained in this way. During this shift operation, the clutch 30 is temporarily switched to the disconnected state by the actuator 19, and then the clutch 30 is brought into the connected state again in synchronization with the end of the shift operation.

The shift map of the transmission 15 that automatically shifts gears in this manner is shown in FIG. 3, and the shift up line shown as a solid line is used during acceleration. That is, when the conditions of vehicle speed and accelerator opening exceed the shift-up line shown by the solid line, the gears are shifted up in sequence, and gradually higher gear positions are selected. On the other hand, when the vehicle is decelerated, a downshift operation is performed each time the downshift line shown by the dotted line is crossed, and the gear position is automatically gradually shifted to a lower gear.

Furthermore, in this automatic transmission 15, the microcomputer 21 is configured to omit switching to second gear during deceleration and to allow reacceleration to be performed while remaining in third gear. Repeat this action in the fourth
To explain based on the flowchart shown in the figure, the microcomputer 21 reads the accelerator opening degree and the vehicle speed using the accelerator sensor 25 and the vehicle speed sensor 26, respectively, and refers to the map stored in the memory, A judgment is made as to whether or not the speed has exceeded the downshift line. When the second gear downshift line is crossed, it is determined whether the accelerator pedal 24 is fully depressed. When the accelerator pedal 24 is fully depressed, it is necessary to accelerate with a large torque, so the microcomputer 21 uses the actuators 17 and 18 to shift the transmission 15 to the starting gear, that is, in this case. At this point, the gear is shifted to 2nd gear, and re-acceleration is performed in this state.

On the other hand, if the accelerator pedal 24 is not fully depressed, the microcomputer 2
1 further detects the engine 10 by the rotation sensor 27.
At the same time as reading the number of revolutions, it is determined whether this number of revolutions is a certain value, for example, 800 rpm or more.
When the rotation speed of the engine 10 is above a certain value,
Even if the shift down line for 2nd speed is crossed, the starting gear is not changed to 2nd speed, but 3rd speed is maintained. In other words, the vehicle will continue to drive in this state without downshifting, and will accelerate again while remaining in 3rd gear. Note that if the rotational speed of the engine 10 is below a certain value, maintaining the third speed will make smooth running impossible, so in this case the transmission 15 will be switched to the second speed.

As described above, according to the transmission 15 according to the present embodiment, even if the vehicle is decelerated and crosses the second gear downshift line, the rotation of the engine 10 remains constant even if the accelerator pedal 24 is not fully depressed. If the number is greater than a predetermined value, the transmission 15 is maintained at the third speed without performing a gear change operation. This means that the shaded area in FIG. 3 is run in third gear. In this way, by holding the vehicle in third gear during deceleration and re-accelerating, it becomes possible to omit wasteful shifting operations and improve fuel efficiency.

〓Effects of the invention〓 As described above, the present invention maintains the engine speed even when the vehicle is traveling at a predetermined speed or below and the vehicle crosses the downshift line for switching to the starting gear. If the accelerator pedal is not fully depressed and the accelerator pedal is not fully depressed, switching to the starting gear is prevented. Therefore, unnecessary gear shifting operations are omitted,
It becomes possible to continue driving by performing gentle acceleration in a gear position higher than the starting gear, and it becomes possible to improve fuel efficiency.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the gist of the invention, Figure 2
Fig. 3 is a block diagram showing an automatic transmission according to an embodiment of the present invention, Fig. 3 is a graph showing a shift map of this automatic transmission, and Fig. 4 shows an operation to prevent switching to a starting gear. It is a flowchart. The names of the main parts in the drawing are as follows.
15... Transmission, 17... Shift actuator, 18... Select actuator, 21... Microcomputer, 25...
Accelerator sensor, 27...Engine rotation sensor.

Claims (1)

[Scope of Claim for Utility Model Registration] In a transmission that calculates an appropriate gear position and automatically changes the gear position using an actuator so as to reach the value obtained by this calculation, a shift actuator and a select actuator for selecting the gear position; a clutch actuator for switching a clutch to a disengaged state when changing the gear position; and a clutch actuator for switching a clutch to a disconnected state when changing the gear position; Even if the state changes beyond the downshift line for switching to the starting gear, if the engine rotational speed is above the predetermined rotational speed and the accelerator pedal is not fully depressed, the shift to the starting gear is performed. An automatic transmission characterized by comprising: means for preventing switching of;