JP2512293B2 - Automatic transmission - Google Patents

Description

The present invention relates to an automatic transmission, and particularly to calculating an appropriate gear position, and automatically adjusting the gear position by an actuator so as to obtain a value obtained by this calculation. Regarding the automatic transmission that has been changed.

[Outline of Invention]

According to the present invention, in an automatic transmission in which the gear position is automatically changed by an actuator so that the gear position is optimally changed, when the clutch is disengaged in order to change the gear position, the operating point of the engine is set in advance. It is designed to shift to a no-load curve along the speed type rack characteristic curve, preventing the feeling of deceleration due to engine blowing up or loss of driving force when disengaging the clutch for gear shifting operation It is something that is done.

[Conventional technology]

An automatic transmission has been proposed in order to save the driver a complicated shifting operation. This automatic transmission selects a gear used by a computing unit such as a microcomputer according to a vehicle speed, an accelerator opening degree, etc., and meshes the gear selected by an actuator to automatically obtain a predetermined gear ratio. It was done. By equipping a vehicle with such an automatic transmission, the driver's gear shifting operation is almost unnecessary.

[Problems to be solved by the invention]

When performing automatic gear shifting in such an automatic transmission, the clutch is disengaged by the actuator in advance. If the output of the engine is not well balanced when the clutch is disengaged, the engine may blow up or the engine brake may be applied.
This phenomenon has the same principle as the phenomenon found during the shift operation of the manual transmission. That is, in a manual vehicle, if the release of the accelerator pedal is delayed when the clutch is disengaged, the engine speed unnecessarily increases. On the contrary, if the accelerator pedal is released too quickly when the clutch is disengaged,
The engine brake seems to be applied. In either case, the feeling that a person on board at the time of shifting receives is not good.

In an automatic transmission in which an actuator disengages the clutch to perform automatic gear shifting, if the engine load or the accelerator opening was left unchanged when the clutch was disengaged, the accelerator pedal was not released when shifting the manual transmission. In the same manner as above, the output of the engine became excessive and the engine blew up, and a shock was felt when the clutch was disengaged.

Therefore, as shown in FIG. 5, the control rack is simply forcibly returned so as to shift the operating point of the engine from A to B. This operation is almost the same as the quick release of the accelerator pedal when shifting the manual transmission. However, even if the operating point shifts to B, the engine is not in a no-load state and has a predetermined output, so when the clutch is disengaged, the torque is released and the load is lost, so the load balance is lost. Becomes,
It was still inconvenient for the engine to blow up. In Fig. 5, the control rack may be forcibly returned at a stretch so that the operating point moves from point B to point D on the no-load curve, but this makes the torque disappear. However, the feeling during shifting is deteriorated, which is not preferable.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an automatic transmission that eliminates engine upswing or a feeling of deceleration when the clutch is disengaged for automatic transmission. It is what

[Means for Solving Problems] According to the present invention, as shown in FIG. 1, an appropriate gear position is calculated, and the gear position is automatically changed by an actuator so as to be a value obtained by this calculation. When disengaging the clutch to change the gear position,
A means for shifting the output torque of the engine to the no-load curve along the rack characteristic curve is provided, and the clutch is completely disengaged when the output torque of the engine shifts to the no-load curve. The present invention relates to a characteristic automatic transmission.

[Action]

Therefore, according to the present invention, when the clutch is disengaged for the automatic shift, the operating point or the output torque of the engine is shifted to the no-load curve along the rack characteristic curve before the clutch is completely disengaged. In this state, the clutch is completely disengaged, so that the load balance is obtained and the engine is prevented from being blown up when the clutch is disengaged. Also, it does not give a feeling of deceleration to the person who is riding. The rack characteristic curve is a governor characteristic, which is a characteristic indicating the relationship between the engine speed and the fuel injection amount.

〔Example〕

Hereinafter, the present invention will be described with reference to one embodiment shown in the drawings. FIG. 2 shows an engine of an automobile equipped with an automatic transmission according to an embodiment of the present invention, which is composed of a diesel engine 10 for trucks. The diesel engine 10 includes a fuel injection pump 11, and the pump 11 sequentially supplies fuel to each cylinder of the engine 10. The fuel injection pump 11 is driven by the engine 10 via a timer 12, and the timing of fuel injection is adjusted by the timer 12. Further, the fuel injection pump 11 includes a mechanical governor 13, and the governor 13 adjusts the fuel injection amount.

Flywheel housing 14 on the back side of engine 10
Is provided, and a flywheel fixed to the end of the crankshaft 11 is accommodated in the housing 14. A clutch 30 is provided on the back side of the flywheel, and a transmission 15 is mounted on the back side of the flywheel housing 14 so as to be connected to the clutch 30.
The transmission 15 changes the rotation speed of the engine 10 to a predetermined value and transmits the rotation to the drive wheels via a propeller shaft 16.

The transmission 15 constitutes an automatic transmission, and a shift actuator is provided above the transmission.
17 and a select actuator 18 are provided. Further, a clutch actuator 19 for controlling connection and disconnection of a clutch 30 mounted on the rear side of the flywheel is mounted on an outer surface of a casing of the transmission 15. Further, on the front end side of the fuel injection pump 11, there is provided a fuel control actuator 20 for adjusting the position of the control rack to control the fuel supply amount. These four actuators 17, 18, 19, 20 are each driven based on a control signal from the microcomputer 21 via driving means.

The input side of the microcomputer 21 is connected to a control box 22. The control box 22 has a speed change lever 23. Further, the microcomputer 21 is connected to an accelerator sensor 25 which detects the accelerator opening degree or the depression amount of the accelerator pedal 24. Further, the microcomputer 21 includes a vehicle speed sensor 26, an engine rotation sensor 27,
The rack sensor 28 and the clutch sensor 29 are connected to each other.

The vehicle speed sensor 26 is provided on the side surface of the transmission 15, and the vehicle speed is detected by the number of rotations on the output side of the transmission 15. The engine rotation sensor 27 is mounted on the front side of the engine 10 and detects the number of revolutions of the engine 10.
The rack sensor 28 is attached to the tip end side of the actuator 20 and detects the position of the control rack of the fuel injection pump 11. Further, the clutch sensor 29 is attached to the distal end side of the clutch actuator 19, and detects the connection and disconnection states of the clutch 30.

Next, the operation of the automatic transmission having the above configuration will be described. This operation is performed based on a program preset in the microcomputer 21, and when the position of the speed change lever 23 of the control box 22 is the automatic position, the speed change operation is automatically performed. There is. On the other hand, when the speed change lever 23 is at the manual position, the manually selected speed change operation is performed via the actuators 17 and 18.

The outline of the automatic shift operation will be described. The microcomputer 21 detects whether or not the position of the shift lever 23 of the control box 22 is the automatic position. In the case of the automatic position, the accelerator pedal 24 is depressed at a constant cycle. The amount or accelerator opening 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 the memory and, based on this map, calculates whether or not automatic gear shifting is possible. Then, when automatic gear shifting is possible, the gear shifting operation is performed so as to obtain the calculated gear ratio. On the other hand, when it is determined that the automatic shift is impossible, the shift operation is not performed.

The specific operation of automatic shifting is performed by the microcomputer 21.
Based on the instruction of the above, the shift actuator 17 and the select actuator 18 are actuated via a drive means (not shown), and the gears of the transmission 15 are selected.
The meshing of the selected gears is achieved. Therefore, a predetermined gear ratio can be obtained in this way. During this shifting operation, the actuator
The clutch 30 is once switched to the disengaged state by 19 and the clutch 30 is brought into the engaged state again in synchronization with the end of the shift operation.

When performing automatic shifting as described above, a microcomputer
Reference numeral 21 is for returning the control rack of the fuel injection pump 11 to prevent the engine 10 from rising when the clutch 30 is disengaged. That is, as shown in FIG. 3, the microcomputer 21 determines whether or not there is a disconnection signal for the clutch 30, and when there is a disconnection signal for the clutch 30, the control rack of the fuel injection pump 11 is set to the actuator for fuel control.
I try to return it at a constant rate depending on 20.

This operation is an operation for returning the operating point of the engine 10 from A to B in FIG. At this time, the clutch 30 is still completely connected and the engine 10 is in the transmission state via the drive wheels and the power line. Therefore, if the vehicle speed is constant, the rotation speed of the engine 10 does not change.

If the operating point of the engine 10 is moved to the position B in FIG. 4, then the microcomputer 21 returns the control rack of the fuel injection pump 11 by the fuel control actuator 20 and returns the rotation speed of the engine 10 to the rack characteristic curve. And gradually increase along the. That is, as shown in FIG. 4, the all-speed type governor characteristic is a characteristic in which the amount of fuel injection decreases as the engine speed increases, so that this characteristic can be used in reverse to control the fuel injection pump control rack. 28 is returned and the operating point of the engine 10 is moved from B to C along the rack characteristic curve while slightly increasing the rotation speed of the engine 10.

When the clutch 30 is disengaged, this operation defines and uses the all-speed characteristic that passes through the point B corresponding to the injection amount at the start of disengagement, and is a characteristic stored in advance in the memory of the microcomputer 21. Is used. Therefore, in accordance with the disengagement operation of the clutch 30, the injection amount corresponding to the point C where the all-speed characteristic used at that time and the no-load curve intersect is shifted. Then, when the operating point reaches C, the clutch 30 is completely disconnected. At this time, the engine rotation becomes a rotation fluctuation amount Δn depending on the all-speed load, and the rotation speed only increases by Δn.

The microcomputer 21 determines whether or not the operating point exceeds the no-load curve, and when the operating point reaches the point C beyond the no-load curve, the microcomputer 21
Ends the control of the control rack of the fuel injection pump 11. In this state, the microcomputer 21 supplies a control signal to the clutch actuator 19 so that the clutch 30 is completely disconnected by the actuator 19 as described above.

The purpose of shifting the output torque of the engine along the rack characteristic curve to the point C where it intersects the no-load curve is to solve the problem that occurs when the clutch 30 is disengaged. This malfunction is the occurrence of a blow-up or a shock that occurs when the output of the engine 10 is not properly adjusted when the clutch 30 is disengaged. That is, if the reduction in the amount of fuel supplied to the engine 10 is delayed when the clutch 30 is disengaged, the rotation of the engine 10 will inadvertently increase. If the amount of fuel supplied to the engine is reduced quickly, the engine brake will be effective.

According to the automatic transmission of the present embodiment that performs the above-described control, the governor characteristic is switched to the all-speed type when the clutch 30 is disengaged, so that the rotation speed of the engine 10 increases depending on the all-speed load. Only minutes Δn. Further, the engine braking more than when the clutch 30 is disengaged will not occur. Therefore, a good feeling can be obtained when the clutch 30 is disengaged.

As described above, according to the automatic transmission according to the present embodiment, when the clutch 30 is disengaged, the output of the engine 10 is controlled using the control rack of the fuel injection pump 11 prior to this. Ten
The control rack is pulled by the actuator 20 so that the operating point of A shifts from A to B. After this, the microcomputer 21 is arranged so that the operating point of the engine 10 shifts from B to C along the rack characteristic curve.
The actuator 20 is used to control the control rack. Therefore, if the clutch 30 is disengaged in this state, the load is balanced, so that the engine 10 only increases its rotational speed by Δn in FIG.
Further, since the control rack is returned along the rack characteristic curve, the feeling of deceleration is eliminated. Therefore, the feeling during shifting of the automatic transmission is improved.

〔The invention's effect〕

As described above, according to the present invention, when the clutch is disengaged for automatic gear shifting, the output torque of the engine is shifted to the no-load curve along the characteristic curve of the rack to balance the load. Therefore, the engine is prevented from being blown up when the clutch is disengaged, and the feeling during shifting is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the gist of the present invention, FIG. 2 is a block diagram showing an automatic transmission according to an embodiment of the present invention, and FIG. 3 is a flowchart showing a clutch disengagement operation for automatic gear shifting. FIG. 4 is a graph showing a clutch disengaging operation, and FIG. 5 is a graph showing a clutch disengaging operation in a conventional automatic transmission. The names of the main parts in the drawings are as follows. 10 …… Diesel engine 11 …… Fuel injection pump 15 …… Transmission 17 …… Shift actuator 18 …… Selection actuator 19 …… Clutch actuator 20 …… Fuel control actuator 21 …… Microcomputer 25 …… Accelerator sensor 26 …… Vehicle speed sensor 28 …… Rack sensor 30 …… Clutch

Claims (1)

(57) [Claims] 1. A transmission in which an appropriate gear position is calculated and the gear position is automatically changed by an actuator so as to obtain the value obtained by this calculation, a clutch is used to change the gear position. A means for shifting the output torque of the engine to the no-load curve along the rack characteristic curve at the time of disengagement is provided, and the clutch is completely disengaged when the output torque of the engine shifts to the no-load curve. The automatic transmission characterized by the above.