JPH0569737B2 - - 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 an 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 driving, the driver of the wheel depresses the accelerator pedal and increases the opening of the throttle valve to accelerate and achieve 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 maintained continuously, and the vehicle runs 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.

However, in the electronically controlled continuously variable transmission described above, when the accelerator adjustment means is operated to accelerate, a target vehicle acceleration is set, and the gear ratio is changed in order to shift the vehicle acceleration to this target vehicle acceleration. No particular consideration is given to the rate of change of the gear ratio at this time. Therefore, when the amount of acceleration operation of the accelerator adjustment means is large, and therefore the difference between the required target vehicle acceleration and the actual vehicle acceleration at that time is large, the transition to the target vehicle acceleration is achieved. It takes a relatively long time to achieve this, and there is a possibility that the acceleration response will not be sufficient.

(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. In addition, even if the required target vehicle acceleration has a large difference from the actual vehicle acceleration at that time, the shift to the target vehicle acceleration can be controlled in a short period of time. An object of the present invention is to provide a gear ratio control device for a continuously variable transmission that can achieve the following.

(Structure of the Invention) The gear ratio control device for a continuously variable transmission according to the present invention, as shown in the basic structure in FIG. A gear ratio adjustment section that changes the gear ratio of the mechanism, an operation detection section that detects the operation state of a required engine output setting means that changes the engine load, a vehicle acceleration detection section that detects the acceleration of the vehicle, and an operation detection section. a target vehicle acceleration setting means for setting a target vehicle acceleration according to the operation of the requested engine output setting means detected by the target vehicle acceleration; and a gear ratio adjustment to continuously achieve the target vehicle acceleration set by the target vehicle acceleration setting means. a control signal supply means for sending a control signal to the vehicle acceleration detection section; a calculation means for calculating the absolute value of the difference between the actual vehicle acceleration detected by the vehicle acceleration detection section and the above-mentioned target vehicle acceleration; A gear ratio change that changes a control signal sent from a control signal supply means in order to operate a gear ratio adjustment unit such that the larger the absolute value of the difference, the greater the speed change speed of the gear ratio of the continuously variable transmission mechanism. and speed control means.

With this configuration, in addition to being able to continuously obtain the required predetermined vehicle acceleration, the amount of acceleration operation of the required engine output setting means is large, so that the required target vehicle acceleration is When the difference from the actual vehicle acceleration becomes large, the speed ratio change speed is made larger than when the difference from the actual vehicle acceleration at that time becomes small. Acceleration can be changed quickly, thereby achieving a transition to the target vehicle acceleration in a short time.

(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 the gear ratio control device for a continuously variable transmission 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 forms branch passages 2a, 2b, 2c, and 2d that communicate with each cylinder.
Fuel injection valves (not shown) are provided at 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 in order to operate the line pressure control valve 37 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 becomes open. 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 applied to the connection solenoid 30 and the 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 However, the shift-up control signal S3 and the shift-down control signal S from the electronic control circuit section 22 described above are
This is done by the speed change control valve 32 which receives the signal 4. That is, the shift-up control signal S3 from the electronic control circuit section 22 is applied to the speed-up solenoid 33 of the speed change control valve 32.
When the speed increasing solenoid 33 is intermittently energized and turned on and off, the cylinder chamber 50c of the drive pulley 50 is controlled according to the control duty of the shift up control signal S3.
Working pressure oil is supplied to the driven pulley 52.
On the other hand, when the downshift control signal S4 is supplied to the deceleration solenoid 34, the deceleration solenoid 34
is intermittently excited and turned on and off, thereby causing the cylinder chamber 52 of the driven pulley 52 to be turned on and off in accordance with the control duty of the downshift control signal S4.
Working pressure oil is supplied to c and the drive pulley 5
The 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 is reduced, and the rotation radius of the V-belt 51 on the driving 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 pulley groove of the drive pulley 50 of the V-belt 51 is The rotation radius 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.
When neither of the solenoids is 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 driving 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 running 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. Engine speed Ne and throttle valve opening Th that can be obtained continuously during the period when the pedal is pressed for acceleration and with minimum fuel consumption.
are set as the target engine speed TNe and the target throttle valve opening TTh, respectively. Then, 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 or a shift down control signal S4 is supplied to control the gear ratio of the continuously variable transmission 9, and a throttle control signal is sent to the throttle actuator 4 so that the target throttle valve opening TTh can be obtained. S6 is supplied to control the throttle valve 3.

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.
This can be determined from the change α' and the output shaft rotation speed No. of the continuously variable transmission 9, which represents the vehicle speed V. 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
is the engine output ω ₁ →ω 2 →ω ₃ → according to the running drive characteristic curve W with the engine output that crosses between point d ₂ and point _{d 3} on curve F ₂ as a parameter.
It is required to change it sequentially to ω ₄ .
In this example, the engine speed Ne and the throttle valve opening Th are set so that the engine output changes from ω ₁ →ω ₂ →ω ₃ →ω ₄ with the minimum fuel consumption. 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 The point e ₁ crossed by the engine outputs ω ₁ , ω ₂ , ω ₃ , ω ₄ ,
Engine speed Ne _{1 , Ne 2} at e ₂ , e ₃ , _{e 4} ,
Ne ₃ and Ne ₄ are the target engine speed TNe, respectively, and points e ₁ ,
Throttle valve opening of those passing through e ₂ , e ₃ , e ₄
Th ₁ , Th ₂ , Th ₃ , and Th ₄ are each set as 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 supplied to the speed increase solenoid 33 and the speed reduction solenoid 34 of the speed change control valve 32 in a predetermined manner. The gear ratio control of the continuously variable transmission 9 is performed such that the following are sequentially 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.
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, engine 1
is the optimal fuel consumption state and the engine output is ω ₁ →
It changes sequentially from ω ₂ →ω ₃ →ω ₄ , and as a result, the set target vehicle acceleration G _T is continuously obtained during the period when the accelerator pedal 23 is depressed for acceleration.

In this example, the continuously variable transmission 9 is operated in order to achieve the target vehicle acceleration G _T set as described above.
When changing the gear ratio of , when the difference between the set target vehicle acceleration G _T and the actual acceleration at that time is large, that is, when the change α' in the accelerator opening α is large, Compared to when the difference between the actual acceleration and the actual acceleration is small, the change in vehicle acceleration can be made quickly, and the target vehicle acceleration G _T
This will reduce the time required to achieve the goal. Therefore, the absolute value of the difference between the actual vehicle acceleration G and the target vehicle acceleration G _T is determined, and the larger the absolute value of this difference, the greater the control duty of the shift-up control signal S3 or the shift-down control signal S4. Control is performed to increase the gear ratio change speed dn/dt of the continuously variable transmission 9.

When the gear ratio changing speed dn/dt of the continuously variable transmission 9 is controlled in this way, in FIGS. 6A and B,
The vertical axis shows the rotation speed (rpm) and the gear ratio, and the horizontal axis shows the time (sec). For example, the change α' in the accelerator opening α when the accelerator pedal 23 is depressed is the same Changes in the input shaft rotation speed Np, output shaft rotation speed Ns, and gear ratio n of the continuously variable transmission 9 under the following conditions are set so that the gear ratio change speed dn/dt is always constant. As shown in the case (Fig. 6A) and the case in which the absolute value of the difference between the vehicle acceleration G and the target vehicle acceleration G _T increases as the value increases (Fig. 6B), If the gear ratio change speed dn/dt is always constant, when the accelerator pedal 23 is depressed, the input shaft rotation speed Np rises and reaches the target engine rotation speed TNe at time _t1 . Rotational speed TNp corresponding to
On the other hand, if the gear ratio change speed dn/dt is increased as the absolute value of the difference between the vehicle acceleration G and the target vehicle acceleration G _T becomes larger, the accelerator pedal 23 is depressed. input shaft rotation speed Np
The time required for the input shaft rotation speed Np to rapidly rise to the rotation speed TNp corresponding to the target engine rotation speed TNe at time t ₂ , and for the input shaft rotation speed Np to reach the rotation speed TNp corresponding to the target engine rotation speed TNe is the time required for the speed change. Compared to the case where the ratio change speed dn/dt is always constant, it is extremely short, and therefore the gear change operation of the continuously variable transmission 9 is performed quickly and the acceleration response of the vehicle equipped with it is improved. performance is significantly improved.

A series of controls during acceleration of the vehicle as described above are the main components of the electronic control circuit section 22.
This is done based on the operation of the CPU 20, but
Figure 7 shows an example of a program executed by the CPU 20.
This will be explained with reference to the flowcharts of FIGS. 8 and 9A and 9B.

First, as shown in FIG. 7, after the start, 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. , a program for clutch control is executed in process 62, followed by a program for speed ratio and throttle valve opening control in process 63, 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 decision 84, where it is determined whether the engine rotational 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, 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 105, the actual vehicle speed Vc at that time is read as the vehicle speed V, and in the subsequent process 106, the road surface slope K obtained from the slope signal P9 and the actual vehicle speed read in the process 105 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 07, the traveling driving force Fe for achieving the target vehicle acceleration G _T set in process 104 is determined.
It is calculated by adding the acceleration resistance Ra to the running resistance F _L obtained in process 106. and,
In the subsequent process 108, the engine output Pe required to achieve the traveling driving force Fe calculated in the process 107 with the minimum fuel consumption, that is,
The engine outputs ω ₁ , ω ₂ , ω ₃ , ω ₄ as shown in FIG. 4 described above are calculated, and the process proceeds to process 109. In _the process 109 _{, the} engine power output in _FIG . Number of revolutions
Target engine speed TNe as shown by Ne ₁ , Ne ₂ , Ne ₃ , Ne ₄ and target throttle as shown in throttle valve openings Th ₁ , Th ₂ , Th ₃ , Th ₄ in FIG. Calculate the tutle valve opening TTh.

Next, the process proceeds to process 110 to calculate the actual vehicle acceleration G at that time based on the transmission output shaft rotation speed signal P8 from the transmission output shaft rotation speed detection sensor 18. The absolute value |G _T −G| of the difference between the target vehicle acceleration G _T and the actual vehicle acceleration G is calculated.
Next, in process 112, according to the absolute value of the difference between the target vehicle acceleration G _T calculated in process 111 and the actual vehicle acceleration G |G _T −G|
The target gear ratio change speed dn'/dt is set so that the larger the absolute value of this difference |G _T -G| is, the larger the target gear ratio change speed dn'/dt is, and the process proceeds to decision 113.

Then, in decision 113, it is determined whether the actual engine speed Ne at that time is higher than the target engine speed TNe calculated in process 109. 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 is performed that has a control duty to achieve the target gear ratio change speed dn'/dt set in process 112. A control signal S3 is sent to the speed increase solenoid 33 of the speed change control valve 32 to turn the speed increase solenoid 33 on and off, and to turn the deceleration solenoid 34 off. As a result, the gear ratio in the continuously variable transmission 9 changes to the target gear ratio change speed.
dn'/dt is made small, and as a result, the input shaft rotational speed Np of the continuously variable transmission 9 is reduced, and at this time,
Since clutch 7 is in the connected state, the engine speed is
Ne is also reduced.

On the other hand, as a result of the judgment in the decision 113, if the engine speed Ne is lower than the target engine speed TNe, the process 115 and the process 112
A downshift control signal S having a control duty to achieve the target gear ratio change speed dn′/dt set in
4 to the deceleration solenoid 34 of the speed change control valve 32 to turn the deceleration solenoid 34 on and off,
The speed increasing solenoid 33 is turned off. As a result, the gear ratio in the continuously variable transmission 9 is increased to the target gear ratio change speed dn'/dt, and as a result, the input shaft rotation speed Np of the continuously variable transmission 9, and therefore the engine rotation speed Ne is forced to rise. In this way,
In process 114 or 115, the actual engine speed Ne is made to match the target engine speed TNe.

Next, the process advances to decision 116, and the actual throttle valve opening Th at that time is determined in process 10.
Target throttle valve opening TTh calculated in 9
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. The degree 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 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. In addition to this, the speed ratio change speed is controlled in accordance with the absolute value of the difference between the target vehicle acceleration G _T and the actual vehicle acceleration G.

On the other hand, if it is determined in the above-described decision 101 shown in FIG.
The vehicle proceeds to step 103, resets the vehicle speed flag indicating a request for constant speed driving, and then proceeds to decision 103 described above.
When it is determined that the shift flag is not in the set state, the process proceeds to decision 121. In decision 121, it is determined whether 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), in the following decision 122. Determine whether the vehicle speed 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, and the vehicle speed flag is set in the subsequent process 124, similar to process 105 described above. Then proceed to process 125. On the other hand, if decision 122 determines that the vehicle speed flag is set, the process directly proceeds to process 125. Then, in process 125, the target vehicle acceleration
Set G _T to 0 and proceed to process 106, below:
As described above, processes 106 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 107
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, the process proceeds to process 128, in which a shift-up control signal S3 having a predetermined control duty is formed to increase the speed in order to reduce the gear ratio n. solenoid 3
3, while if it is small, process 1
29, a downshift control signal S4 having a predetermined control duty is sent to increase the gear ratio n.
is formed and sent to the deceleration solenoid 34 to control 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 reduce 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 the vehicle is smoothly driven. Deceleration takes place.

(Effects of the Invention) As is clear from the above description, according to the gear ratio control device for a continuously variable transmission according to the present invention, the target vehicle acceleration is set in accordance with the operation of the required engine output setting means such as the accelerator pedal. The gear ratio of the continuously variable transmission mechanism is controlled so that the target vehicle acceleration is continuously achieved, and the gear ratio change speed is controlled according to the absolute value of the difference between the target vehicle acceleration and the actual acceleration. The larger the absolute value of the difference, the larger the difference, so during the acceleration period of the vehicle,
The required vehicle acceleration is continuously obtained by increasing the driving force as the running resistance increases due to the increase in vehicle speed, and the driver can not only obtain a sufficient sense of acceleration, but also have the required vehicle acceleration. When the difference between the actual vehicle acceleration and the actual vehicle acceleration is large, the gear change operation of the continuously variable transmission mechanism is faster than when the difference between the actual vehicle acceleration and the actual vehicle acceleration is small. This is done to quickly change the vehicle acceleration, thereby shortening the time it takes to reach the target vehicle acceleration and improving the acceleration response of the vehicle.

[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 together with an electronically controlled continuously variable transmission to which the same is applied; FIG. 4 , Figure 5 and Figure 1
Fig. 0 is a characteristic diagram used to explain the operation of the example shown in Fig. 3, and Figs. Characteristic diagrams for comparison and explanation with operating characteristics;
FIGS. 7, 8, and 9A and 9B are flowcharts showing an example of an operation program in the electronic control circuit section used in the example shown in FIG. In the diagram, 1 is the engine, 3 is the slot valve, and 7
9 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 a vehicle; and a required engine output setting unit that changes the load of the engine. an operation detection section that detects an operation state; a vehicle acceleration detection section that detects acceleration of the vehicle; and a target vehicle that sets a target vehicle acceleration according to the operation of the requested engine output setting means detected by the operation detection section. acceleration setting means; control signal supply means for sending a control signal to the gear ratio adjusting section in order to continuously achieve the target vehicle acceleration set by the target vehicle acceleration setting means; calculation means for calculating the absolute value of the difference between the actual vehicle acceleration and the target vehicle acceleration; and a calculation means for calculating the absolute value of the difference between the actual vehicle acceleration and the target vehicle acceleration; A gear ratio control device for a continuously variable transmission, comprising: control means for changing a control signal sent from the control signal supply means in order to operate the gear ratio adjustment section.