JPH0569738B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a gear ratio control device that controls a gear ratio in a continuously variable transmission mechanism provided in a power transmission path from a vehicle engine to drive wheels.

(Prior art) In vehicles, in order to efficiently transmit the output of the engine to the wheels, which are driven objects, a transmission mechanism is disposed between the engine and the wheels, and the output of the engine is transmitted to the wheels via the transmission mechanism. As this transmission mechanism, one that employs a continuously variable transmission mechanism that can continuously change the transmission ratio within a predetermined range is known. The continuously variable transmission mechanism installed in such a vehicle is adjusted by adjusting the vehicle speed or engine rotation speed and the operation of an accelerator adjustment means such as an accelerator pedal, as described in Japanese Patent Application Laid-open No. 55-76709, for example. The gear ratio is controlled based on the throttle valve opening. In such a case, the gear ratio of the continuously variable transmission mechanism is usually controlled so that the engine rotational speed, and therefore the input rotational speed of the continuously variable transmission mechanism, is uniquely determined by the throttle valve opening. be done. That is, the gear ratio is controlled so that a constant engine speed is obtained for each throttle valve opening value, and therefore a constant engine output is obtained.

By the way, while the vehicle is driving, the driver of the vehicle depresses the accelerator pedal and increases the opening of the throttle valve to accelerate to the desired speed. In other words, in order to maintain a feeling of acceleration, it is desirable that a constant increase in the throttle valve opening degree be maintained at a predetermined magnitude.

However, in the case of a vehicle equipped with the above-mentioned continuously variable transmission mechanism, the continuously variable transmission mechanism is a transmission system that maintains the engine speed constant for each throttle valve opening value. Since ratio control is performed, the engine speed increases to a predetermined value immediately after the accelerator pedal is depressed, and
After the engine output increases accordingly, the increased engine output is continuously maintained, and the vehicle travels at a constant engine output. Then, while the vehicle is running at a constant engine output after this acceleration, the vehicle speed increases, and running resistance increases accordingly. Despite the increase in running resistance that accompanies the increase in vehicle speed, the engine output remains constant, so even if the driver continues to press the accelerator pedal at a constant rate, the driving force of the vehicle will not decrease. The acceleration gradually decreases.
Therefore, the driver is dissatisfied with the sense of acceleration. Furthermore, during acceleration or deceleration, the gear ratio control of the continuously variable transmission mechanism is performed immediately to keep the engine speed constant, so the engine sound does not change dynamically and the driver does not have any audible complaints. You will feel it.

Therefore, in order to solve the above-mentioned problems, the present applicant first set a target vehicle acceleration according to the operation of an accelerator adjustment means such as an accelerator pedal in Japanese Patent Application No. 58-205043. In order to continuously achieve the target vehicle acceleration, we proposed an electronically controlled continuously variable transmission that controls the gear ratio of the continuously variable transmission mechanism. According to such an electronically controlled continuously variable transmission, during the acceleration period, the running driving force is increased as the running resistance increases due to the increase in vehicle speed. It is possible to provide the driver of the vehicle with a sufficiently satisfying sense of acceleration when stepping on the accelerator for acceleration.

By the way, as described above, when a target vehicle acceleration is set according to the operation of the accelerator adjustment means and control is performed to continuously maintain this target vehicle acceleration, the problem is how long the target vehicle acceleration is to be maintained. . In other words, when the target vehicle acceleration is maintained continuously, the vehicle speed gradually increases, but when considering the suppression of excessively high vehicle speeds or the prevention of so-called engine overrun, the target vehicle acceleration may be changed regardless of the situation. There may be cases in which it is not desirable to maintain the condition continuously.

(Object of the Invention) In view of the above, the present invention sets a target vehicle acceleration according to the operation of a required engine output setting means such as an accelerator pedal, and provides a continuously variable transmission mechanism to continuously achieve this target vehicle acceleration. A gear ratio control device for a continuously variable transmission is designed to control the gear ratio of a continuously variable transmission, and can prevent the vehicle from reaching excessively high vehicle speeds, as well as avoid inconveniences such as engine overrun. The purpose is to provide.

(Structure of the Invention) A gear ratio control device for a continuously variable transmission according to the present invention includes:
As shown in FIG. 1, its basic configuration includes a gear ratio adjustment section that changes the gear ratio of a continuously variable transmission mechanism installed in the power transmission path from the engine to the wheels of the vehicle, and A speed detection section that detects the rotation speed of the installed engine, an operation detection section that detects the operation state of a request engine output setting means such as an accelerator pedal that changes the engine load, and a request detected by this operation detection section. A target vehicle acceleration setting means for setting a target vehicle acceleration according to the operation of the engine output setting means, and an upper limit for setting the upper limit vehicle speed or the upper limit engine rotation speed according to the operation of the requested engine output setting means detected by the operation detection section. speed setting means, and
Based on the signal obtained from the speed detection section, a control signal is sent to the gear ratio adjustment section in order to continuously achieve the target vehicle acceleration until the vehicle reaches the above-mentioned upper limit vehicle speed or until the engine reaches the above-mentioned upper limit engine speed. and a gear ratio control section including a control signal supply means for sending out a control signal.

With this configuration, based on the operating state of the required engine output setting means, the running vehicle reaches the upper limit vehicle speed determined by the operating state of the required engine output setting means, or the engine changes to the required engine output setting. The set predetermined acceleration is continuously obtained until the upper limit engine speed determined by the operation status of the means is reached.
The acceleration state can be canceled when the upper limit vehicle speed or upper limit engine speed is exceeded. Therefore, it is possible to provide the driver with a desirable sense of acceleration, and to avoid excessively high vehicle speeds and engine overruns.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 shows an outline of a drive control section of a vehicle to which an example of a gear ratio control device for a continuously variable transmission mechanism according to the present invention is applied. In FIG. 2, a throttle valve 3 for changing the load of the engine 1 is disposed in an intake passage 2 of the engine 1. As shown in FIG. This throttle valve 3 is driven to open and close by a throttle actuator 4, and its opening degree is detected by a throttle position sensor 5. Note that the end of the intake passage 2 on the downstream side of the throttle valve 3 is
Branch passages 2a, 2b, 2c, and 2d are arranged to communicate with each cylinder, and each of these branch passages 2
Fuel injection valves (not shown) are provided at a, 2b, 2c, and 2d.

An output shaft 6 of the engine 1 is connected to a continuously variable transmission 9 via a clutch 7 and a switching gear train 8, and an output shaft 10 of the continuously variable transmission 9 is connected to drive wheels 12 via a differential gear 11. It is connected.

Also, an engine rotation speed detection sensor 13 that detects the rotation speed of the output shaft 6 of the engine 1, a clutch output shaft rotation speed detection sensor 15 that detects the rotation speed of the output shaft 14 of the clutch 7, and an input shaft of the continuously variable transmission 9. 16
A transmission input shaft rotation speed detection sensor 17 detects the rotation speed of the continuously variable transmission 9, and a transmission output shaft rotation speed detection sensor 18 detects the rotation speed of the output shaft 10 of the continuously variable transmission 9, and therefore the vehicle speed. Installed in place. Throttle position signal P5 from the aforementioned throttle position sensor 5, engine speed signal P2 from the above-mentioned engine speed detection sensor 13, and clutch output shaft rotation speed from the clutch output shaft rotation speed detection sensor 15. signal P4,
The transmission input shaft rotation speed signal P6 from the transmission input shaft rotation speed detection sensor 17 and the transmission output shaft rotation speed signal P8 from the transmission output shaft rotation speed detection sensor 18 are transmitted to the interface section 19 and the CPU 20, respectively. The signal is input to an electronic control circuit unit 22 which includes a memory 21 as a main component.

Further, the amount of depression of the accelerator pedal 23 operated by the driver, that is, the accelerator opening is detected by the accelerator opening detection sensor 24, and the depression state of the brake pedal 25 is detected by the brake operation detection sensor 24.
6, and furthermore, the shift position of the shift lever 27 is detected by the shift lever position detection sensor 2.
8, and the slope of the road surface is further detected by the slope sensor 55, and an accelerator opening signal P1, which corresponds to the amount of depression of the accelerator pedal 23, is detected by the slope sensor 55.
Brake activation signal P3 obtained when the brake pedal 25 is depressed, shift lever 27
A shift lever position signal P7 corresponding to the position of and a slope signal P9 corresponding to the road surface slope are
Each is input to the electronic control circuit section 22.

Then, various control signals S1, S2, S3, S4, S5, and S6 are sent out from the electronic control circuit section 22 based on the signals P1 to P9 obtained and input from each sensor.

FIG. 3 shows an example of the gear ratio control device for a continuously variable transmission according to the present invention, to which the gear ratio control device is applied, and the clutch 7 and the switching gear are interposed in the power transmission system from the engine 1 to the drive wheels 12. 1 schematically shows the entire electronically controlled continuously variable transmission device including a gear train 8, a continuously variable transmission 9, and an electronic control circuit section 22.

Here, the various control signals S1 to S6 from the electronic control circuit section 22 are such that the clutch connection control signal S1 excites the connection solenoid 30 of the clutch control valve 29, and the clutch disconnection control signal S2 excites the connection solenoid 30 of the clutch control valve 29. In order to energize the cutoff solenoid 31, a shift up control signal S3 is sent to the speed change control valve 3.
A shift down control signal S4 is used to energize the speed increasing solenoid 33 of No. 2 with a predetermined duty, and a line pressure control signal S4 is used to energize the deceleration solenoid 34 of the speed change control valve 32 with a predetermined duty.
5 causes the line pressure control valve 37 to operate as described below, and the throttle control signal S
6 operates the throttle actuator 4 to adjust the opening degree of the throttle valve 3.
It is assumed that each will be supplied.

The clutch actuator 41, the continuously variable transmission 9, and the shift actuator 44 are connected to the clutch control valve 29, the shift control valve 32, and the shift lever 27 by the driver's manual operation. Hydraulic oil is sucked from the oil tank through the filter 35 and discharged by the oil pump 36 through the shift control valve 43 which is controlled by being switched to N, drive D, and low L shift positions. It is supplied through each oil path.

The electronically controlled continuously variable transmission which is controlled by being supplied with hydraulic oil in this manner is capable of transmitting the output of the engine 1 to the drive wheels 12 and controlling it as described below. It is composed of

That is, the rotation of the output shaft 6 of the engine 1 is first
A flywheel 38 provided at the end of the output shaft 6
The signal is transmitted to a clutch 7 which is intermittently pressure-connected to the output shaft 6 and rotates coaxially with the output shaft 6. This clutch 7 has a friction plate 39 that presses against the flywheel 38, and a diaphragm-shaped clutch spring 40 to which a pressure plate that presses the friction plate 39 is fixed, and the clutch connection control signal S1 is transmitted to the clutch control valve. 29, the connection solenoid 30 is energized and turned on, thereby supplying hydraulic oil from the open port to the clutch actuator 41, inside which the piston is moved by the elasticity of the spring. , and rotates the lever 42 counterclockwise. As a result, the clutch spring 40 in the open state is moved to the closed state and presses the friction plate 39, thereby bringing the clutch 7 into the connected state. As a result, the rotation of the output shaft 6 of the engine 1 is transmitted to the output side of the clutch 7.

Further, when the clutch cutoff control signal S2 is sent to the cutoff solenoid 31 of the clutch control valve 29, the cutoff solenoid 31 is energized and turned on, and the hydraulic oil is discharged from the clutch actuator 41, and the internal The piston is returned by the elasticity of the spring, and the clutch spring 40 is opened. As a result, the friction plate 3
The pressing state of the clutch 9 against the flywheel 38 is released, and the clutch 7 is brought into the disengaged state. In this state, the rotation of the output shaft 6 of the engine 1 is not transmitted to the output side of the clutch 7.

Further, a clutch connection control signal S1 and a clutch disconnection control signal S2 are sent to the connection solenoid 30 and cutoff solenoid 31 of the clutch control valve 29.
When neither is delivered, the open port of the clutch control valve 29 is closed and the piston in the clutch actuator 41 is maintained in its immediately previous position, thus causing the flywheel 3 of the friction plate 39 to close.
The pressed state for 8 is maintained.

On the output side of the clutch 7 that operates in this way,
To the input shaft 16 of the continuously variable transmission 9, the shift lever 27
A switching gear train 8 is provided so that the rotation of the output shaft 6 of the engine 1 is transmitted according to each of the above-mentioned shift positions. This switching gear train 8 is configured such that when the shift lever 27 is placed in the drive D or low L position, the piston of the shift actuator 44 moves in the direction D in the figure, and the forward gear is fixed to the output shaft 14 of the clutch 7. A gear 46 provided on the input shaft 16 of the continuously variable transmission 9 engages with the gear 45 for connecting the input shaft 16 of the continuously variable transmission 9 to the output shaft 14 of the clutch 7.
and rotate it in the opposite direction. On the other hand, shift lever 2
7 is placed in the reverse R position, the piston of the shift actuator 44 moves in the R direction in the figure.
A gear 47 provided on the input shaft 16 of the continuously variable transmission 9
is engaged with the idler gear 49 that is engaged with the reverse gear 48 fixed to the output shaft 14 of the clutch 7, and the input shaft 16 of the continuously variable transmission 9 is moved as in the case of the drive D described above. The clutch 7 is rotated in the opposite direction, that is, in the same direction as the output shaft 14 of the clutch 7. Furthermore, when the shift lever 27 is placed in the neutral N position, the piston of the shift actuator 44 is held in the center of the cylinder, and the rotation of the output shaft 14 of the clutch 7 is directed to the input shaft 16 of the continuously variable transmission 9. done without being communicated.

The continuously variable transmission 9 to which the rotation of the output shaft 14 of the clutch 7 is transmitted includes an input shaft 16 that rotates coaxially with the output shaft of the switching gear train 8, and a drive that rotates integrally with the input shaft 16. It has a pulley 50, a driven pulley 52 to which rotation of the drive pulley 50 is transmitted via a V-belt 51, and an output shaft 10 that rotates integrally with the driven pulley 52.

The drive pulley 50 has a movable conical plate 50a and a fixed conical plate 50b.
0a and the fixed conical plate 50b have their conical surfaces facing each other to form a V-shaped pulley groove. A cylinder chamber 50c is provided behind the movable conical plate 50a.
Fixed conical plate 50b depending on the supply state of hydraulic oil to
The fixed conical plate 50b is axially slidable toward or away from the input shaft 16. The fixed conical plate 50b is fixed to the input shaft 16. On the other hand, the driven pulley 52 has the same configuration as the driving pulley 50 described above, and a V-shaped pulley groove is formed by a movable conical plate 52a and a fixed conical plate 52b, and the movable conical plate 52a is located behind the movable conical plate 52a. Depending on the state of supply of working pressure oil to the provided cylinder chamber 52c, it can be slid in the axial direction so as to approach the fixed conical plate 52b, and the fixed conical plate 52b is fixed to the output shaft 10.

A V-belt 51 is stretched over each of the pulley grooves formed in the drive pulley 50 and the driven pulley 52, thereby transmitting the rotation of the drive pulley 50 to the driven pulley 52. And drive pulley 5
When transmitting zero rotation to the driven pulley 52, the V-belt 5 determined by the width of the pulley groove of the drive pulley 50
The V-belt 51 is determined by the rotation radius on the driving pulley 50 side of 1 and the width of the pulley groove of the driven pulley 52.
By changing the rotation radius on the driven pulley 52 side, the rotation ratio between the driving pulley 50 and the driven pulley 52 can be changed.

The widths of the pulley grooves of the driving pulley 50 and the driven pulley 52 are changed by sliding the respective movable conical plates 50a and 52a in the axial direction, and the sliding control of the movable conical plates 50a and 52a This is performed by the shift control valve 32 which receives the shift-up control signal S3 and the shift-down control signal S4 from the electronic control circuit section 22 described above.
That is, the shift-up control signal S3 from the electronic control circuit section 22 is applied to the speed-up solenoid 3 of the speed change control valve 32.
3, the speed increasing solenoid 33 is intermittently energized and turned on and off.
As a result, the cylinder chamber 50 of the drive pulley 50 is adjusted according to the control duty of the shift-up control signal S3.
Working pressure oil is supplied to c and the driven pulley 5
The working pressure oil is removed from the cylinder chamber 52c of No. 2,
On the other hand, when the downshift control signal S4 is supplied to the deceleration solenoid 34, the deceleration solenoid 3
4 is intermittently energized and turned on and off, whereby hydraulic oil is supplied to the cylinder chamber 52c of the driven pulley 52 and the driving pulley 50 is turned on and off in accordance with the control duty of the downshift control signal S4. Working pressure oil is removed from the cylinder chamber 50c. Further, when both the speed increase solenoid 33 and the deceleration solenoid 34 are turned off, the supply and removal of hydraulic oil to and from the cylinder chambers 50c and 52c of the drive pulley 50 and the driven pulley 52, respectively, is stopped.

Therefore, when the speed increasing solenoid 33 is turned on or off by the shift-up control signal S3, the movable conical plate 50a is moved in a direction approaching the fixed conical plate 50b, and the movable conical plate 50a is moved toward the fixed conical plate 50b.
The width of the pulley groove formed by the fixed conical plate 50b and the fixed conical plate 50b is reduced, and the rotation radius of the V-belt 51 on the drive pulley 50 side is enlarged. At the same time, the movable conical plate 52a is moved in a direction away from the fixed conical plate 52b, and the movable conical plate 52a is moved away from the fixed conical plate 52b.
The width of the pulley groove formed by the fixed conical plate 52b and the fixed conical plate 52b is expanded, and the radius of rotation of the V-belt 51 on the driven pulley 52 side is reduced. Therefore, the gear ratio in the continuously variable transmission 9 becomes small. On the other hand, when the deceleration solenoid 34 is turned on/off by the downshift control signal S4, the width of the pulley groove of the drive pulley 50 is expanded, and the width of the drive pulley 50 of the V-belt 51 is increased. The radius of rotation on the side is reduced, and at the same time the driven pulley 5
The width of the second pulley groove is reduced, and the rotation radius of the V-belt 51 on the driven pulley 52 side is expanded. Therefore, in this case, the gear ratio in the continuously variable transmission 9 is made large. Further, a shift-up control signal S3 and a shift-down control signal S4 are applied to the speed increase solenoid 33 and the deceleration solenoid 34.
If none of the solenoids are delivered and each solenoid is turned off, the width of the pulley groove of each of the driving pulley 50 and the driven pulley 52 is maintained unchanged, and therefore the width of the V-belt 51 is maintained unchanged. The respective rotation radii on the drive pulley 50 side and the driven pulley 52 side are maintained, and the gear ratio in the continuously variable transmission 9 is adjusted to the speed increase solenoid 33 and the deceleration solenoid 3.
4 is kept at the state immediately before it was turned off.

In this way, the driving pulley 50 and the driven pulley 5
In the continuously variable transmission 9, which is capable of continuously changing the gear ratio by changing the supply state of hydraulic oil to each of the cylinder chambers 50c and 52c, the required traveling driving force is The larger the movable conical plate 50 is relative to the V-belt 51.
By increasing the pressing force of a and 52a, the V-belt 5
1 (transmission torque capacity of the V-belt 51) needs to be increased. Therefore, in this example, the oil pump 36 is connected to the speed change control valve 3.
2, the oil pressure of the working pressure oil supplied to the cylinder chamber 50c or 52c, that is, the line pressure, is adjusted by the line pressure control valve 37 that receives the line pressure control signal S5 from the electronic control circuit section 22. It is done like this. That is, the line pressure control valve 37
For example, the amount of oil passing through and being discharged can be changed depending on the level of the line pressure control signal S5 supplied to the solenoid 37a, and in this case, the line pressure The higher the level of the control signal S5, the lower the amount of oil discharged and the higher the line pressure.

In an example of the gear ratio control device for a continuously variable transmission according to the present invention as described above, when the vehicle is accelerating, the accelerator pedal is activated for acceleration based on the change in the accelerator opening degree α detected by the accelerator opening detection sensor 24. 23 is detected. and,
The electronic control circuit section 22 sets the vehicle acceleration to be obtained at that time as the target vehicle acceleration G _T based on the change α' in the _accelerator opening degree α. The engine speed Ne and throttle valve opening Th that can be obtained continuously and with the minimum fuel consumption during the period when the pedal is pressed for acceleration are the target engine speed TNe and the target throttle. Each is set as the valve opening degree TTh. Then, the shift-up control signal S3 or the shift-down control signal S4 is supplied to the speed change control valve 32 to control the gear ratio of the continuously variable transmission 9 so that the target engine speed TNe is obtained, and the gear ratio of the continuously variable transmission 9 is controlled. Target throttle valve opening
A throttle control signal S6 is supplied to the throttle actuator 4 to control the throttle valve 3 so as to obtain TTh.

In this case, while the vehicle is running, the accelerator pedal 23 is depressed and the vehicle enters an acceleration state. For example, in FIG. 4, the horizontal axis represents the vehicle speed V, and the vertical axis represents the driving force Fe. In characteristics, curve
Assuming that point d ₁ on F ₁ transitions to point d ₂ on curve F ₂ , the acceleration corresponding to the difference in driving force between this point d ₂ and point d ₁ is the target vehicle acceleration G _T. Ru. These points d ₁ and d ₂ are the accelerator opening α and the accelerator opening α when the accelerator pedal is depressed for acceleration.
A bulletless transmission 9 representing the change α' and the vehicle speed V
This can be determined from the output shaft rotation speed No. In order to maintain this target vehicle acceleration G _T continuously until the acceleration state of the vehicle is released and the vehicle returns to point d ₄ on curve F ₁ , the traveling driving force characteristic curve passing through point d ₂ must be maintained. It is necessary to move on F ₂ to point d ₃ corresponding to point d ₄ . For this, engine 1
_{ω 1 → ω 2} → _{ω 3 →}
It is required to change it sequentially from ω ₄ to ω ₅ . In this example, the engine speed is adjusted so that the engine output changes from ω ₁ → ω ₂ → ω ₃ → ω ₄ → ω ₅ with the minimum fuel consumption.
Ne and throttle valve opening Th are controlled.

By the way, as shown in Fig. 5, the horizontal axis represents the engine speed Ne, and the vertical axis represents the engine torque T.
There is an optimal fuel consumption zone Z in the power source characteristics of the engine 1, which is shown by taking Engine speed at points e ₁ , e ₂ , e ₃ , e ₄ , e ₅ crossed by engine outputs ω ₁ , ω ₂ , ω ₃ , ω ₄ , ω ₅
Ne ₁ , Ne ₂ , Ne ₃ , Ne ₄ , and Ne ₅ are each set as the target engine speed TNe, and the power source characteristic curve TH with the throttle valve opening Th as a parameter
Throttle valve openings Th ₁ , Th ₂ , Th ₃ , Th ₄ , Th ₅ of those passing through points e ₁ , e ₂ , e ₃ , e ₄ , e ₅
are each assumed to be the target throttle valve opening TTh.
Then, the shift-up control signal S3 and the shift-down control signal S4 from the electronic control circuit section 22 are
The speed increasing solenoid 3 of the speed change control valve 32 in a predetermined manner
3 and reduction solenoid 34, thereby controlling the gear ratio of the continuously variable transmission 9 such that the target engine speed TNe is successively achieved, and the throttle control signal S6 from the electronic control circuit section 22. is supplied to the throttle actuator 4 in a predetermined manner, and the opening degree of the throttle valve 3 is controlled so that the above-mentioned target throttle valve opening degree TTh is successively achieved. As a result, when the vehicle accelerates, the engine 1 is in the optimal fuel consumption state and its engine output changes sequentially from ω ₁ → ω ₂ → ω ₃ → ω ₄ → ω ₅ , and as a result, the accelerator pedal 2
During the period in which the pedal 3 is pressed for acceleration, the set target vehicle acceleration G _T is continuously obtained.

Here, when the accelerator pedal 23 is held in a depressed state and the set target vehicle acceleration G _T is continuously achieved as described above, the vehicle speed V and the engine rotation speed Ne increase. There is a risk that the vehicle speed will be excessively high or the engine 1 will be in an overrun state.

Therefore, in this example, the electronic control circuit unit 22 takes the upper limit vehicle speed Vs on the vertical axis and the accelerator opening on the horizontal axis in FIG. Based on the predetermined relationship as shown by taking α,
An upper limit vehicle speed Vs corresponding to the accelerator opening degree α with the accelerator pedal 23 depressed is set. Then, during the acceleration period when the accelerator pedal 23 is depressed and held, the target vehicle acceleration G _T is continuously obtained and the vehicle speed V is increased, and the target vehicle acceleration G T is set according to the accelerator opening degree α at that time. When the vehicle speed reaches the upper limit vehicle speed Vs, the target vehicle acceleration G _T
is newly set to 0, and when this is achieved, the acceleration state is released.

Therefore, when the vehicle speed V reaches the upper limit vehicle speed Vs, the engine speed Ne and the throttle valve are adjusted to achieve the target vehicle acceleration G _T set to 0, that is, to set the actual vehicle acceleration G to 0. The opening Th is set as a target engine speed TNe and a target throttle valve opening TTh, respectively, and a shift up control signal S is sent to the speed change control valve 32 so that the target engine speed TNe is obtained.
3 and the shift down control signal S4 are supplied to control the gear ratio of the continuously variable transmission 9, and
A throttle control signal S6 is supplied to the throttle actuator 4 to control the throttle valve opening Th so that the target throttle valve opening TTh can be obtained.

In this case _, assuming that _the upper limit vehicle speed Vs is the vehicle speed corresponding to _{the point d 3 on the} curve F ₂ in FIG. This is necessary. For this purpose, the engine 1 sequentially changes its output from ω ₅ to ω 3 according to the running drive characteristic curve W, which takes as a parameter the engine output that crosses between points d ₃ and _{d 4} on the curve F ₂ . We are required to continue to change.

In this example, the engine rotational speed Ne and the throttle valve opening Th are controlled so that such changes in engine output can be achieved with minimum fuel consumption. That is, in the above-mentioned FIG. 5, the engine speed Ne 5 and the throttle valve at the point e ₅ where the engine output is ω ₅ intersects the power source characteristic curve W' in which the zone Z is the engine output as a _parameter . The opening Th ₅ is at the upper limit vehicle speed Vs, and from this engine speed Ne ₅ and throttle valve opening Th ₅ ,
The engine speed Ne ₄ is adjusted along the zone Z to achieve the engine speed Ne ₃ and throttle valve opening Th ₃ at the point e ₃ where the engine output is ω ₃ of the power source characteristic curve W′ crosses, respectively. The target engine speed TNe and the target throttle valve opening TTh are sequentially set so that the target engine speed TNe and the target throttle valve opening TTh are decreased through the throttle valve opening Th ₄ and the target engine speed TNe and the target throttle valve opening TTh. The gear ratio control and throttle valve opening of the continuously variable transmission 9 are
Th control is performed.

As a result, the output of the engine 1 changes in an optimum fuel consumption state, and the actual vehicle acceleration G is set to 0, resulting in a constant vehicle speed running state in which a constant vehicle speed is continuously maintained.

A series of controls during acceleration of the vehicle as described above are performed based on the operation of the CPU 20 of the electronic control circuit section 22, and examples of programs executed by the CPU 20 are shown in FIGS. 7, 8, and 9. Diagram A
This will be explained with reference to the flowcharts of and B.

First, as shown in FIG. 7, after starting, initial settings are made for each part in process 60, and then in process 61, data obtained based on the signals obtained from each sensor are inputted, and the process proceeds to process 62. In process 62, a program for clutch control is executed, then in process 63, a program for controlling the gear ratio and throttle valve opening is executed, and the process returns to process 61.

An example of a program for clutch control executed in the above process 62 is as shown in FIG. Here, after the start, at day 70, the shift lever is currently 2.
7 is in the neutral range (N range) position, and if the shift lever 27 is in the neutral range position, in process 71. The vehicle speed flag is reset, and in the subsequent process 72, a clutch cutoff control signal S2 is sent to the cutoff solenoid 31 of the clutch control valve 29, and the cutoff solenoid 31 is turned on and the connection solenoid 3 is turned on.
0 is the off state. As a result, clutch 7
is considered to be in a cut-off state.

If decision 70 determines that the shift lever 27 is not in the neutral range position, decision 73 determines that the current vehicle speed V is greater than a preset predetermined vehicle speed Va. Determine whether or not. Here, vehicle speed Va
is set to a vehicle speed at which there is a high risk of engine stoppage, and if it is determined that the vehicle speed V is greater than the vehicle speed Va, the following process 74 is performed.
Set the vehicle speed flag and proceed to decision 75.

In decision 75, engine speed
It is determined whether the change Ne′ in Ne is positive or negative, and if the change Ne′ in engine speed Ne is positive, decision 76 determines that the engine speed Ne is greater than the clutch output shaft speed Nc. Determine whether or not.
If it is determined that the engine speed Ne is greater than the clutch output shaft speed Nc, process 77
A clutch connection control signal S1 is sent to the connection solenoid 30 of the clutch control valve 29, turning the connection solenoid 30 on and turning the cutoff solenoid 31 off. As a result, clutch 7
The friction plate 39 is made to press against the flywheel 38, and the transmission torque capacity of the clutch 7 gradually increases. Further, if it is determined at decision 76 that the engine speed Ne is smaller than the clutch output shaft speed Nc, the process proceeds to process 79, where both the clutch connection control signal S1 and the clutch disconnection control signal S2 are It is prevented from being delivered and both the connection solenoid 30 and the cutoff solenoid 31 are turned off. As a result, the current state of pressing the friction plate 39 of the clutch 7 against the flywheel 38 is maintained, and therefore,
The transmission torque capacity of the clutch 7 is maintained as it is.

On the other hand, if it is determined at decision 75 that the amount of change Ne' in the engine speed Ne is negative, the process proceeds to decision 78, where it is determined whether the engine speed Ne is smaller than the clutch output shaft speed Nc. If the engine speed Ne is smaller than the clutch output shaft speed Nc,
Proceed to process 77. As a result, the transmission torque capacity of the clutch 7 gradually increases as described above. If it is determined at decision 78 that the engine speed Ne is not smaller than the clutch output shaft speed Nc, the process proceeds to process 79 where the connection solenoid 30 and the cutoff solenoid 31 are activated as described above.
Both are turned off.

If it is determined in decision 73 that the current predetermined vehicle speed V is not greater than the vehicle speed Va,
Proceeding to decision 80, it is determined whether the accelerator pedal 23 is on, that is, whether the accelerator pedal 23 is depressed, and the accelerator pedal 23 is turned on.
If it is determined that the switch 3 is in the on state, the process proceeds to decision 75, and the process proceeds as described above.

On the other hand, the accelerator pedal is 23 at decision 80.
If it is determined that the vehicle speed flag is not in the on state, decision 81 determines whether the vehicle speed flag is in the set state. If the vehicle speed flag is in the set state, decision 82 determines whether the brake pedal 25 is in the on state or not. That is, it is determined whether or not the brake pedal 25 is depressed, and if it is determined that the brake pedal 25 is in the on state, the process advances to decision 83. If it is determined at decision 81 that the vehicle speed flag is not set, the process proceeds to process 72, in which the cutoff solenoid 31 is turned on and the connection solenoid 30 is turned off, as described above.

Then, in decision 83, it is determined whether or not the engine speed Ne is less than a predetermined value, for example 1500 rpm. Here, engine speed
1500 rpm is a rotation speed that may cause the engine to stop when the brake pedal 25 is on. If the engine rotation speed Ne is not below 1500 rpm, the process proceeds to decision 75, and the flow as described above is followed. Proceed with If the engine speed Ne is 1500 rpm or less, the process proceeds to process 71, and the process proceeds as described above.

If the decision 82 determines that the brake pedal 25 is not in the on state, the process proceeds to a decision 84, where it is determined whether the engine speed Ne is below a predetermined value, for example 1000 rpm. Here, engine speed
1000 rpm is a rotation speed that may cause the engine to stop when the brake pedal 25 is in the OFF state, and if the engine rotation speed Ne is not below 1000 rpm, the process proceeds to decision 75, and the flow as described above is followed. Proceed with On the other hand, if the engine speed Ne is 1000 rpm or less, the process proceeds to process 71, and the process proceeds as described above.

Next, an example of the program for controlling the gear ratio and throttle valve opening degree executed in the process 63 of the program shown in FIG.
As shown in Figures A and B. Here, first, as shown in FIG. 9A, after the start, at decision 101, the accelerator opening signal P1 is
The change status of the accelerator opening α is determined based on
If it is determined that the accelerator opening degree α has increased, the process proceeds to process 102, and if it is determined that the accelerator opening degree α has not changed, the process proceeds to decision 103.

Then, in process 102, which is proceeded when it is determined that the accelerator opening degree α has increased, a shift flag indicating an acceleration request is set, and the process proceeds to process 104. On the other hand, in decision 103, which is proceeded when it is determined that the accelerator opening degree α has not changed, it is determined whether or not the shift flag is in the set state, and if it is determined that it is in the set state, the step is proceeded to process 104. .

In process 104, as described above using FIG. 6, the upper limit vehicle speed is determined according to the actual accelerator opening α.
Set Vs. Then, the process proceeds to decision 105, where the actual vehicle speed V is obtained based on the transmission output shaft rotation speed signal P8 obtained from the transmission output shaft rotation speed detection sensor 18.
It is determined whether the vehicle speed is lower than the upper limit vehicle speed Vs set in step 04. Here, the actual vehicle speed V is the upper limit vehicle speed
If it is determined that the speed is not smaller than Vs, the process proceeds to process 106, sets a vehicle speed flag representing constant vehicle speed driving, and proceeds to decision 122, which will be described later.
On the other hand, if it is determined that the actual vehicle speed V is smaller than the upper limit vehicle speed Vs, the process proceeds to process 107.

In process 107, the variation α' is obtained from the accelerator opening α used in decision 101, and based on this variation α', the variation α' and the target vehicle acceleration G _T as shown in FIG. The target vehicle acceleration G _T is set from the map representing the correspondence relationship between the two. In the subsequent process 108, the actual vehicle speed Vc at that time is read as the vehicle speed V, and in the subsequent process 109, the road surface slope K obtained from the slope signal P9 and the actual vehicle speed read in the process 108 are read.
Based on Vc, the running resistance F _L of the vehicle at that time is calculated. Note that this running resistance F _L is the slope resistance
_Rk is calculated from rolling resistance Rr and air resistance Ri.

Subsequently, as shown in FIG. 9B, process 1
Proceeding to step 10, the traveling driving force Fe for achieving the target vehicle acceleration G _T set in process 107 is calculated as follows:
It is calculated by adding the acceleration resistance Ra to the running resistance F _L obtained in process 109. and,
In the subsequent process 111, the engine output Pe required to achieve the traveling driving force Fe calculated in the process 110 with the minimum fuel consumption, that is,
The engine outputs ω ₁ , ω ₂ , ω ₃ , ω ₄ , ω ₅ as shown in FIG. 4 described above are calculated, and the process 112
Proceed to. In the process 112, the process 1 at points e ₁ , e ₂ , e ₃ , e ₄ , e ₅ as shown in FIG.
The target engine speed TNe as shown by engine speeds Ne ₁ , Ne ₂ , Ne ₃ , Ne ₄ , Ne ₅ in FIG. and also the fifth
In the figure, the throttle valve openings Th ₁ , Th ₂ ,
The target throttle valve opening degree TTh as shown by Th ₃ , Th ₄ , and Th ₅ is calculated.

Then, in decision 113, it is determined whether the actual engine speed Ne is higher than the target engine speed TNe calculated in process 112.
As a result of this judgment, if the actual engine speed Ne is higher than the target engine speed TNe, in process 114, a shift-up control signal S3 is sent to the speed increase solenoid 33 of the speed change control valve 32, and the speed increase solenoid 33 is activated. The deceleration solenoid 34 is turned on and off, and the deceleration solenoid 34 is turned off. As a result, the gear ratio in the continuously variable transmission 9 is made small, and as a result,
The input shaft rotational speed Np of the continuously variable transmission 9 is reduced, and since the clutch 7 is in the connected state at this time, the engine rotational speed Ne is also reduced.

On the other hand, as a result of the determination in decision 113, if the engine speed Ne is lower than the target engine speed TNe, in process 115, the speed change control valve 3
A shift down control signal S4 is sent to the second deceleration solenoid 34 to turn the deceleration solenoid 34 on and off, and the speed increase solenoid 33 is turned off. As a result, the gear ratio in the continuously variable transmission 9 is increased, and as a result, the input shaft rotation speed of the continuously variable transmission 9 is increased.
Np, and therefore the engine speed Ne, is increased. In this way, the actual engine speed Ne is determined by the operation of process 114 or 115.
to match the target engine speed TNe.

Next, the process proceeds to decision 116, where the actual throttle valve opening Th at that time is determined in process 11.
Target throttle valve opening TTh calculated in 2
If it is larger, in process 117 a throttle control signal S6 is sent to the throttle actuator 4 to reduce the throttle valve opening. If Th is reduced, and if it is small,
In process 118, throttle actuator 4
The throttle control signal S6 that increases the throttle valve opening is sent to increase the throttle valve opening.
Increases Th. The operation of process 117 or 118 causes the actual throttle valve opening Th to match the target throttle valve opening TTh.

In this way, in the flow from decision 101 to process 118, the gear ratio n and throttle valve opening Th are adjusted to obtain a predetermined target vehicle acceleration G _T with minimum fuel consumption while the accelerator is being depressed or during the subsequent depression holding period. Control is exercised.

On the other hand, if it is determined that the accelerator opening degree α is decreasing at the above-described decision 101 shown in FIG. The vehicle speed flag indicating that driving is requested is reset, and then, in the case where it is determined that the shift flag is not in the set state at decision 103 described above, decision 121 is executed.
Proceed to. At decision 121, it is determined whether or not the position of the shift lever 27 determined from the shift lever position signal P7 is in the low range (L range). If it is determined that it is not in the low range (L range), the vehicle speed is changed at the subsequent decision 122. Determine whether the flag is set. Here, if it is determined that the vehicle speed flag is not set, the process proceeds to process 123, where the actual vehicle speed Vc at that time is read as the vehicle speed V, similar to process 108 described above, and the vehicle speed flag is set in the following process 124. Proceed to process 125. On the other hand, if it is determined in decision 122 that the vehicle speed flag is in the set state, the process directly proceeds to process 125. Then, in process 125, the target vehicle acceleration
Set G _T to 0 and proceed to process 109, as follows:
As described above, processes 109 to 1
18 are executed sequentially. In this case, the target vehicle acceleration
Since G _T is set to 0, acceleration resistance Ra is set to 0,
Vehicle driving force calculated in process 110
When Fe becomes equal to running resistance F _L , the vehicle runs at a constant speed, and the optimal fuel consumption state is maintained even when running at this constant speed.

If it is determined in decision 121 that the vehicle is in the low range L, the process proceeds to process 126, where a target gear ratio n _T corresponding to vehicle speed V is set. Next, proceeding to decision 127, the ratio Np/Ns of the input shaft rotation speed Np to the output shaft rotation speed Ns at that time, that is, the actual gear ratio n at that time is determined as the target gear ratio n _T set in process 126. If it is larger, the process proceeds to process 128 and sends a shift up control signal S3 to the speed increase solenoid 33 to reduce the gear ratio n. If so, the process proceeds to process 129, where a downshift control signal S4 is sent to the deceleration solenoid 34 to increase the gear ratio n, thereby controlling the gear ratio.

Then, in the subsequent process 130, a throttle control signal S6 is supplied to the throttle actuator 4 in a predetermined manner in order to decrease the throttle valve opening Th, and the throttle actuator 4 is operated in the closing direction.

Thus, processes 126 to 130
, a target gear ratio n _T is set according to the vehicle speed V, and gear ratio control is performed to achieve this target gear ratio n _T , so that effective engine braking is applied to the vehicle and deceleration is achieved. It's done smoothly.

In addition, in the above example, the accelerator pedal 2
3 is depressed and held, the range in which the target vehicle acceleration G _T is continuously maintained is determined based on the vehicle speed V. However, the gear ratio control device for a continuously variable transmission according to the present invention For example, the range in which the target vehicle acceleration G _T is continuously maintained may be determined based on the engine speed Ne, and in that case, the engine speed Ne is the upper limit engine speed. Control is performed to continuously maintain the target vehicle acceleration G _T until the target vehicle acceleration G The gear ratio is controlled so as to match the number.

(Effects of the Invention) As is clear from the above description, the gear ratio control device for a continuously variable transmission according to the present invention, when the required engine output setting means such as the accelerator pedal is operated, A target vehicle acceleration is set, and the gear ratio of the continuously variable transmission is controlled to continuously achieve the target vehicle acceleration, and furthermore,
The range in which the target vehicle acceleration is continuously maintained is determined by the upper limit vehicle speed or upper limit engine speed set based on the operating state of the requested engine output setting means, and the actual vehicle speed or engine speed is determined by the upper limit vehicle speed or upper limit engine speed. During the acceleration period, the system is configured so that the vehicle speed or engine speed does not increase any further when the maximum speed is reached.
As the running resistance increases due to the increase in vehicle speed, the running driving force is increased, and the required vehicle acceleration is continuously obtained.In addition to giving the driver a sufficient sense of acceleration, the vehicle is It is possible to prevent the vehicle from entering a high vehicle speed state or from suddenly accelerating at a high vehicle speed, and furthermore, it is possible to prevent the engine from going into an overrun state.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram of a gear ratio control device for a continuously variable transmission according to the present invention, and FIG. 2 is a drive control section of a vehicle to which an example of the gear ratio control device for a continuously variable transmission according to the present invention is applied. FIG. 3 is a schematic configuration diagram showing an example of the gear ratio control device for a continuously variable transmission according to the present invention, and FIG. 4 is a schematic configuration diagram showing an electronically controlled continuously variable transmission configured by applying the same. , FIGS. 5, 6, and 10 are characteristic diagrams used to explain the operation of the example shown in FIG. 3, and FIGS. 7, 8, and 9 A and B are shown in FIG. 2 is a flowchart showing an example of an operation program in an electronic control circuit unit used in an example in which the present invention is used. In the diagram, 1 is the engine, 3 is the throttle valve,
7 is a clutch, 9 is a continuously variable transmission, 22 is an electronic control circuit, 23 is an accelerator pedal, 24 is an accelerator opening detection sensor, and 32 is a speed change control valve.

Claims (1)

[Scope of Claims] 1. A gear ratio adjustment unit that changes the gear ratio of a continuously variable transmission mechanism provided in a power transmission path from the engine to the wheels of the vehicle; and detecting the vehicle speed of the vehicle or the rotational speed of the engine. a speed detection section; an operation detection section that detects an operation state of the required engine output setting means for changing the load of the engine; and a target vehicle acceleration according to the operation of the required engine output setting means detected by the operation detection section. means for setting an upper limit vehicle speed or an upper limit engine rotation speed according to the operating state of the required engine output setting means detected by the operation detecting section; a control unit including means for sending a control signal to the gear ratio adjustment unit to continuously achieve the target vehicle acceleration until the vehicle reaches the upper limit vehicle speed or until the engine reaches the upper limit engine speed; A gear ratio control device for a continuously variable transmission, comprising: