JPS6060364A - Speed ratio control device of continuously variable transmission for vehicle - Google Patents

Abstract

PURPOSE:To improve drivability of a vehicle and its economic efficiency of fuel, by suppressing the change of speed of an engine during the time after deceleration of the vehicle is started till the lapse of a predetermined time is discriminated. CONSTITUTION:A deceleration condition discriminating means, time counting means and a rotary speed change suppressing means are provided, and the change of speed of an engine is suppressed during the time after the deceleration of a vehicle is started till the lapse of a predetermined time is discriminated by the time counting means. In this way, a good characteristic of reacceleration (drivability) of the vehicle and its high economic efficiency of fuel are obtained by limiting a decrease of transmission efficiency of a continuously variable transmission even when the vehicle is reaccelerated because the speed of the engine is maintained at a relatively high value even under a decelerated condition of the vehicle.

Description

Detailed Description of the Invention Technical Field The present invention relates to a speed ratio control device for a continuously variable transmission for a vehicle, and in particular to a technology that provides both favorable drivability and fuel economy in a state of re-acceleration following vehicle deceleration. It is.

Technical field A continuously variable transmission for a vehicle that continuously changes the speed of the engine and transmits it to the wheels, a rotation speed detection means for detecting the rotation speed of the engine, and a required load amount detection means for the engine. , target rotation speed determining means for sequentially determining a target rotation speed of the engine based on the required load meter from a predetermined relationship; A speed ratio control device including a speed ratio adjusting means for adjusting the speed ratio of a transmission has been considered. If such a speed ratio control device is used, the engine rotation can be made to match the target rotation speed with the best fuel consumption rate, so that favorable fuel economy can be obtained over the entire engine rotation range, especially in steady running conditions. However, there is a drawback that sufficient drivability and fuel economy cannot be obtained when the vehicle is reaccelerated following deceleration. That is, even when the vehicle is decelerating when the accelerator operation amount is almost zero, the engine rotation speed is controlled to match the target rotation speed that is determined to be an extremely low value corresponding to the accelerator operation amount, and When the vehicle is in a re-acceleration state where the accelerator operation is large again, the engine rotation speed is made to match the target rotation speed that is largely determined in accordance with the amount of accelerator operation, so the engine rotation speed increases. The width is large, and the amount of change in the speed ratio of the continuously variable transmission becomes large, which reduces the transmission efficiency of the continuously variable transmission and requires a long time to accelerate the vehicle, making it difficult to achieve sufficient re-acceleration (drivability) and fuel economy. This makes it impossible to have sex.

Purpose of the Invention The present invention has been made against the background of the following two circumstances, and its purpose is to provide a continuously variable vehicle that provides high drivability and fuel economy in a state of re-acceleration following vehicle deceleration. An object of the present invention is to provide a speed ratio control device for a transmission.

Structure of the Invention In order to achieve the above object, the speed ratio control device for a continuously variable transmission for a vehicle of the present invention includes: (2) a deceleration state determining means for determining a deceleration state of the vehicle; (2) a start of deceleration of the vehicle; (3) a clock means for later determining whether a predetermined time has elapsed; and a rotational speed change suppressing means for suppressing the change.

Effects of the Invention With this arrangement, as shown in the claim correspondence diagram in FIG. The speed change suppressing means suppresses changes in the rotational speed of the engine until the predetermined time period elapses.

In other words, when the vehicle decelerates, changes in the engine rotational speed are suppressed until a predetermined period of time elapses from the start of deceleration, so when the vehicle decelerates, the amount of accelerator operation is almost zero, and the target rotation is determined to be a significantly smaller value. Compared to the conventional case where the actual engine rotational speed is lowered to follow the speed, changes in engine rotational speed are suppressed and the engine rotational speed is maintained at a relatively high value even in such a deceleration state. It is. Therefore, in the reacceleration state that follows such deceleration, the target rotational speed is determined to be a large value according to the amount of accelerator operation, but the engine rotational speed is maintained at a relatively high value during deceleration. Therefore, even during re-acceleration, the range of increase in the engine rotational speed and the range of change in the speed ratio of the continuously variable transmission are relatively small, limiting the decrease in transmission efficiency of the continuously variable transmission, and improving re-acceleration performance (drivability). ) and at the same time high fuel economy.

Furthermore, as a result of suppressing changes in engine rotational speed when the vehicle is decelerating, the engine rotational speed is maintained at a relatively high value, but in such a case, the amount of accelerator operation is essentially zero. Because of this condition, fuel economy will not be affected by this condition.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 2, a belt type continuously variable transmission 14 is connected to the engine 10 via a clutch 12, and after the rotation of the engine 10 is continuously changed by the belt type continuously variable transmission 14, wheels (not shown) It is intended to be transmitted to The belt type continuously variable transmission 14 includes an input shaft 16 connected to the clutch 12, a variable pulley 18 with a variable effective diameter attached to the input shaft 16, an output shaft 20, and an output shaft 2.
Variable boob IJ 22 with variable effective diameter attached to 0
, a transmission heald 24 that is hooked between the variable pulleys 18 and 22, and hydraulic cylinders 26 and 28 that change the V-groove width of the variable pulleys 18 and 22 to change their effective diameters. The variable pulleys 18 and 22 are fixed rotating bodies 3 fixed to the input shaft 16 and the output shaft 20, respectively.
o and 32, and movable rotating bodies 34 and 36 which are attached to the input shaft 16 and the output shaft 2o so as to be movable in the axial direction but not rotatable around the axes, and these movable rotary bodies 34 and 36 are attached to the hydraulic cylinder 26. and the hanging diameter (effective diameter) of the transmission heald 24 by being driven in the axial direction by the hydraulic pressure applied to the space within 28.
can be changed continuously. and,
Line hydraulic pressure is constantly supplied to the hydraulic cylinder 28 via an oil path 46 (described later), and the amount of hydraulic oil (operating hydraulic pressure) in the hydraulic cylinder 26 is adjusted by a speed ratio control valve 38, so that the movable rotating body 34 and The speed ratio of the continuously variable transmission 14 is changed by changing the balance of forces applied to the continuously variable transmission 36. In addition, the movable rotating body 3
The pressure receiving area of No. 4 is set larger than that of the movable rotating body 36.

The line oil pressure is obtained by adjusting the hydraulic oil pressure-fed from the oil tank 40 by the pump 42 by the pressure regulating valve 44, and then passing it through the oil passage 46 to the speed ratio control valve 3.
8 and hydraulic cylinder 28. The pressure regulating valve 44 includes a linear solenoid driven by a pressure regulating signal SP, which will be described later, and a valve element driven by the linear solenoid I, and regulates the amount of hydraulic oil pumped from the pump 42 that escapes to the oil tank 40. The line oil pressure is adjusted by changing it according to the signal SP.

The speed ratio control valve 38 includes a linear solenoid driven by a speed ratio signal SS, which will be described later, and a valve element driven by the linear solenoid, and connects an oil passage 48 communicating with the hydraulic cylinder 26 with the oil passage 46. By changing the flow area, the supply M (hydraulic pressure) of hydraulic oil to the hydraulic cylinder 26 is adjusted, while the oil passage 48 and the oil tank 4
By communicating with the return oil passage 50 to 0 and changing its circulation area, the amount of hydraulic oil discharged in the hydraulic cylinder 26 (
(hydraulic). That is, when the communication between the oil passage 48 and the oil passages 46 and 50 is substantially cut off by the speed ratio control valve 38 and the amount of hydraulic oil in the hydraulic cylinder 26 is kept constant, the speed ratio is fixed. , when the oil passage 48 and the oil passage 46 are in communication with each other, the hydraulic cylinder 2
The hydraulic oil M (hydraulic pressure) in 6 is increased and the variable pulley 1
The effective diameter of the variable boob U 22 is made larger, and the effective diameter of the variable boob U 22 is made smaller, thereby increasing the speed ratio.

On the contrary, the speed ratio is reduced by making the oil passage 48 and the oil passage 50 communicate with each other.

A throttle valve 54 connected to an accelerator pedal 52 is attached to the intake pipe of the engine 10, and the opening degree θ of the throttle valve 54 is corresponded to by a throttle sensor 56, which is attached to the throttle valve 54 and serves as a required load detection means. The throttle signal TH, which is the voltage
It is supplied to the I10 boat 59 via the D converter 58. Further, a rotation sensor 60 as a rotation speed detection means and a rotation sensor 62 as a vehicle speed detection means are respectively attached to the input shaft 16 and the output shaft 2o to detect the rotation of the engine 10. I/F circuit 64 sends a pulsed rotation signal SE corresponding to
Meanwhile, the rotation sensor 62 supplies a pulsed rotation signal SC corresponding to the vehicle speed to the T/F circuit 64. T/
The F circuit 64 converts the rotation signals SE and SC into a code signal representing the number of pulses per unit time, and supplies the code signal to the I10 port 59. The I10 port 59 is connected to a CPU 66 and a RAM 68° ROM 70 via a data bus line, and the CPU 66 utilizes the temporary storage capability of the RAM 68 according to a program stored in advance in the ROM 70 while reading signals supplied to the I10 port 59. process,
A speed ratio signal SS that commands the speed ratio and its rate of change is supplied to the speed ratio control valve 38 via the D/A converter 72 and the drive circuit 74, while a pressure regulation signal SP that commands the pressure of the line hydraulic pressure is supplied to the speed ratio control valve 38 via the D/A converter 72 and the drive circuit 74. It is supplied to the pressure regulating valve 44 via the A converter 72 and the drive circuit 74. The drive circuit 74 is a so-called power amplifier,
The speed ratio signal SS and pressure regulation signal SP outputted from the D/A converter 72 are amplified in power by a predetermined gain and supplied to the linear solenoids of the speed ratio control valve 38 and the pressure regulation valve 44.

FIG. 3 is a control block diagram of this embodiment.

The target rotational speed determining means 76 determines the required load amount from the throttle valve 5 based on the pre-stored relationship shown in FIG.
The target rotational speed Ne' is determined based on the opening degree θ of No. 4. The target rotational speed Ne' is the opening degree θ of the throttle valve 54.
This is a predetermined value so that the required horsepower corresponding to the required horsepower can be obtained at the minimum fuel consumption rate. The deceleration state determination means 78 determines the deceleration state of the vehicle depending on the sign of the difference between the actual vehicle speed determined by the vehicle speed detection means 80 and the vehicle speed determined a predetermined time ago. The counting means 82 determines that a predetermined period of time has elapsed since the deceleration state of the vehicle was determined by the deceleration state determining means 78, and the time interval 1 determining means 84 determines that a predetermined period of time has elapsed since the deceleration state of the vehicle was determined by the deceleration state determining means 78. The time interval until the counting means 82 determines that a predetermined time has elapsed is determined. That is, the counting means 8
2 and the time interval determining means 84 constitute a time measuring means. The rotation speed change suppressing means 86 changes the content of the target rotation speed Ne' to the actual rotation speed Ne determined by the rotation speed detection means 88 only within the time interval determined by the time interval determination means 84. In the shift control control means 90, the vehicle speed detection means 80
The vehicle speed V detected by, in other words, the continuously variable transmission 14
The actual speed ratio e is determined based on the rotation speed NO of the output shaft of the engine 10 and the actual rotation speed Ne of the engine 10, in other words, the rotation speed Ni of the input shaft of the continuously variable transmission 14. A target speed ratio e' is determined to make the rotational speed Ne match the target rotational speed Ne', and the speed ratio adjusting means 9
At step 2, the speed ratio signal SS is supplied to the speed ratio control valve 38 so that the difference between e and e' becomes zero, and the speed ratio e of the belt type continuously variable transmission 14 is changed.

On the other hand, the engine torque detection means 94 detects the actual rotational speed of the engine 10 based on the pre-stored relationship shown in FIG. Detect output torque T. The line pressure determination means 96 determines the actual torque T1 of the engine 10 from a predetermined relationship, the actual rotational speed Ne of the engine 10 detected by the rotational speed detection means 88, and the continuously variable transmission 14 detected by the vehicle speed detection means 80. The line oil pressure of the oil passage 46 is determined based on the output shaft rotation speed No. The pressure regulating valve adjusting means 98 supplies a pressure regulating signal SP, which is a control voltage for maintaining the line oil pressure determined by the line pressure determining means 96, to the pressure regulating valve 44. As a result, the line oil pressure is maintained at a minimum pressure within a range where the transmission belt 24 does not slip, thereby preventing power loss and deterioration in the durability of the transmission belt 24 due to excessive line oil pressure.

The operation of this embodiment will be described below in flowchart 3 of FIG. Explain according to the following.

First, step S1 is executed, and the opening degree θ of the throttle valve 54 and the actual rotational speed Ne of the engine 10 are determined by the signal T.
It is read based on H and SE and stored in the RAM 6B. Then, step S2 corresponding to the target rotational speed determination means 76 is executed, and the target rotational speed Ne' is calculated based on the opening degree θ of the throttle valve 54 from the predetermined relationship shown in FIG. Subsequently, step S3 corresponding to the deceleration state determining means 7B is executed, and it is determined whether the content of the flag FV indicating the deceleration state of the vehicle is zero. Flag FV if the vehicle is not decelerating
Since the content of flag FV is 1, the speed ratio control routine in step S6, which will be described later, is executed. However, if the vehicle is in a deceleration state and the content of flag FV is zero, step S3 is executed.
is executed, and it is determined whether the content TC1 of the 44-hour counter (register), which will be described later, is smaller than a predetermined constant time t□.

Here, the contents of the flag Fv are determined by the interrupt routine shown in FIG. 7, which is executed at regular intervals. That is, step SWI is executed and it is determined whether or not the content of the timer flag FT is 1. If not, the interrupt routine is terminated, but if it is 1, step SW2 and subsequent steps are executed. . The contents of this timer flag FT are set to 1 at regular time intervals. In steps SW2 and SW3, 1 is added to the contents of TC1 and TC2 of the predetermined time measurement force 1'', respectively, and then step SW4 is executed.
1 value ``r c '' is a predetermined constant time t2
It is determined whether or not it is smaller than . That certain time t2
corresponds to a predetermined fixed time interval for detecting changes in vehicle speed and determining the acceleration state of the vehicle, and is set larger than the execution cycle of the interrupt routine.

In step SW4, the count value TC2 is changed for a part of time t2.
If it is smaller than 11, the interrupt routine is terminated.
However, if it is larger than the previously read vehicle speed VO, step SW5 is executed and the actual vehicle speed V is read based on the signal SC, and step SW6 is executed so that the actual vehicle speed Whether it is smaller or not is determined by I:ll lji. If it is smaller, the vehicle is in a decelerating state, so step SW7 is executed and the contents of the flag FV are cleared to zero. Subsequently, steps SW8 and SW9 are executed, and the coefficient value TC
The content of 2 is cleared to zero, and the content of the previous vehicle speed VO becomes a value slightly smaller than the actual vehicle speed■
-α and the contents of the old timer flag FT are set to zero.

The reason why the content of the previous vehicle speed Vo is set to V-α is that the actual rotational speed Ne of the engine 10 is changed to the target rotational speed Ne so that it is not judged as deceleration in a slight deceleration state where the decrease value of the vehicle speed is within α. This is to improve fuel economy by matching the '. On the other hand, if the actual vehicle speed V is larger than the previous vehicle speed Vo in step SW6, step 5WIO is executed and the content of flag FV is set to 1 to represent the acceleration state of the vehicle, and step 5W
II is executed and the contents of the count value 'rC□ are cleared to zero6. By executing this step 5W11, the count value TC
As long as the contents of , are in a decelerating state of the vehicle, they are incremented at fixed time intervals as the interrupt routine is executed, and corresponds to step 5W24 and the counting means 82.

Returning to FIG. 6, flag F is set by executing step S3.
If the content of V is zero and it is determined that the vehicle is in a deceleration state, step S4 corresponding to the time interval determining means 84 is performed.
is executed, and the count value TC□ is set to a predetermined constant value t.
It is determined whether or not it is smaller than 1. If it is not small, step S6 is executed, but if it is still small, step S corresponding to the rotation speed change suppressing means 86 is executed.
5 is executed and the contents of the target rotational speed Ne' are changed to the actual rotational speed Ne. As a result, when the speed ratio control routine of step S6 is executed as described later, the deviation between the target value and the actual value is made zero, and the rotational speed change ΔNe' of the engine 10 is controlled to be zero.

”= Recording speed control routine 1 is 7 as shown in FIG. executed.

That is, in the speed ratio control routine, step SRI is first executed, and the rotational speed Ni of the input shaft 16 and the rotational speed NO of the output shaft 20 of the continuously variable transmission 14 are calculated based on the rotational signals SE and SC. Then, step SR2 is executed, and the rotational speed Ni of the input shaft 16 is
Based on the rotational speed NO of the output shaft 20, the actual speed ratio e (=No/Ni) of the continuously variable transmission 14 is calculated, and step SR3 is executed, and the target speed ratio e'
(=No/N i ') is calculated. Next, step SR4 is executed, and the target speed ratio e' becomes the minimum speed ratio e.
It is determined whether or not the target speed ratio e' is smaller than min. If it is smaller, step SR5 is executed and the content of the target speed ratio e' is set to the minimum speed ratio e min, but if it is not smaller, step SR6 is executed. It is determined whether the target speed ratio e' is smaller than the maximum speed ratio e max. If the target speed ratio e' is not smaller than the maximum speed ILemax, step SR7 is executed and the content of the target speed ratio e' is set to the maximum speed ratio 8 e + nax, but if it is smaller, the next step SR8 is executed. be done.

In step SR8, the deviation Δe between the target speed ratio e' and the actual speed ratio e is calculated, and in step SR9, the flow rate control voltage Vf, which is the control amount to make the deviation equation 〇 zero, is calculated using the following equation. A speed ratio signal SS determined according to (1) and representing the flow rate control voltage Vf is supplied to the speed ratio control valve 38, and the speed ratio e of the continuously variable transmission 14 is adjusted.

That is, steps SRI to SR8 correspond to the speed change control means 90, and step SR9 corresponds to the speed ratio adjusting means 92.

■1 for f- ・2 for e+ ・Δe − (11 However, K,
, 2 is a constant.

Next, step 5RIO is executed, which corresponds to the engine torque detecting means 94, and the actual torque T of the engine 10 is calculated from the predetermined relationship shown in FIG. Then, step 5RII corresponding to the line pressure determining means 94 and the pressure regulating valve adjusting means 98 is executed, and the pressure regulating valve control voltage Vp, which is a control amount for controlling the line pressure, is executed.
is calculated according to the following equation (2) stored in advance, and the pressure regulating signal sp representing the voltage Vp is sent to the pressure regulating valve 44.
supplied to

Vp-f (T, Ni, No) -42) Thus,
According to this embodiment, since the content of the target rotational speed Ne' is changed to Ne in step S5, the rotational speed Ne is changed within a partial time tl from the deceleration start time A, as shown by the solid line in FIG. Since the change is suppressed, the engine rotational speed Ne is maintained higher than in the conventional case shown by the broken line. As a result, when the accelerator pedal 52 is operated after re-acceleration start time B, the increase in the engine speed Ne is small and the change in the speed ratio e is made small.
The transmission efficiency of the continuously variable transmission 14 is maintained, resulting in high fuel economy and good drivability (re-acceleration). Furthermore, even if the engine speed Ne is maintained higher than before when the vehicle is decelerating, the accelerator operation amount is essentially zero in such a case, so this will not impair fuel economy. be. Furthermore, in a continuously variable transmission, the more the speed ratio is changed, the more the transmission efficiency inevitably decreases in the process.

Next, another embodiment of the present invention will be described. In the following description, parts common to those in the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 10, steps S7 to 310 may be executed between steps S3 and 84 in FIG. 6. That is, steps S7 and S corresponding to the suppressed rotational speed determining means 100 described below
8 is executed, the vehicle speed V is read based on the signal SC, and the suppression rotational speed Ne1 is determined based on the vehicle speed from the predetermined relationship shown in FIG. The one-dot chain line in Fig. 11 is the optimum value at the time of road loading (during an experiment in which running resistance is applied with one dynamometer).

Then, step S9 corresponding to the rotation range determining means 102, which will be described later, is executed, and the actual rotation speed N of the engine 10 is
It is determined whether e is smaller than the suppressed rotational speed Ne1. If the actual rotational speed Ne is larger than the suppressed rotational speed Ne, step SIO is executed and the count value TC is
After the contents of 1 are set to zero, the speed ratio control routine of step S6 described above is executed, but if the actual rotational speed Ne of the engine IO is smaller than the suppressed rotational speed Ne□, the above-described embodiment is performed. Similarly, steps 84 and subsequent steps are executed.

FIG. 12 is a control block diagram of this embodiment.

According to this embodiment, as shown by the solid line in FIG.
When the rotational speed decreases to e, the change in the rotational speed of the engine 14 is suppressed within a predetermined partial time t.
When the vehicle is re-accelerated following deceleration, the increase in the engine speed Ne is 2 times smaller than in the conventional case shown by the broken line in FIG. 13, and the change in the speed ratio e of the continuously variable transmission 14 is also reduced. , high drivability and fuel economy are achieved.

Further, according to this embodiment, the section t□ during vehicle deceleration
Since the engine rotation speed Ne is maintained at the suppressed rotation speed Ne, which is set to an appropriate value that is slightly smaller than the actual engine rotation speed Ne, compared to when the rotation speed change of the engine 10 is set to zero, This has the advantage of preventing the disadvantage that the engine rotational speed Ne is maintained higher than necessary in the section where changes in the rotational speed Ne during deceleration are suppressed.

Note that if the suppressed rotational speed Ne1 is too large, drivability and fuel economy during re-acceleration are improved, but on the other hand, Ne becomes too large during deceleration, causing problems such as excessive engine braking and noise.

Furthermore, if Ne is too small, drivability and fuel economy during re-acceleration will be impaired, so Ne□ is set at a balance point between the two, and may be a constant value. In this case, if the suppressed rotational speed Ne is kept constant, steps S7 and 3B become unnecessary.

Since the suppressed rotational speed Ne1 is determined to be larger as the vehicle speed V increases according to the relationship shown in FIG. 11, optimum re-acceleration performance and fuel economy can be achieved regardless of the vehicle speed. It goes without saying that even if the suppressed rotational speed Ne1 is set to a constant value regardless of the vehicle speed (2), the effects of the present invention can still be obtained to some extent.

Although one embodiment of the present invention has been described above in detail based on the drawings, the present invention can also be applied to other aspects.

For example, although the belt-type continuously variable transmission 14 is described in the above embodiment, other types of continuously variable transmissions may be used.

Further, in the above embodiment, the opening degree θ of the throttle valve 54 is used to detect the required load of the engine 10, but the operating amount of the accelerator pedal 52, the intake pipe negative pressure of the engine 10, etc. It is okay to do so. in short,
Any amount that represents the required load amount of the engine 10 may be used.

4 In addition, although the deceleration state determination means 78 described above determines the deceleration state of the vehicle based on the fact that the actual vehicle speed ■ is smaller than the vehicle speed Vo determined a certain period of time ago, the deceleration state determination means 78 does not detect the deceleration state of another vehicle. The output signal of the accelerometer obtained may also be used.

Further, the predetermined constant time t1 used in step S4 described above may be determined based on a predetermined relationship that is changed according to changes in the vehicle speed V. In this way, since the rotational speed change suppression time of the continuously variable transmission 14 is changed in accordance with changes in vehicle speed, there is an advantage that optimum acceleration performance and fuel economy can be obtained regardless of the vehicle speed.

Further, in step S5 described above, the target rotational speed Ne'
is changed to the actual rotational speed pJe of the engine 10, but it is changed to a value slightly smaller than the actual rotational speed Ne, for example, Ne-α (however, α is an extremely small value) or Ne′+β (however, , β may be changed to a value slightly smaller than the difference between Ne' and Ne. In this case, the speed ratio etJ of the continuously variable transmission 14 during the 5 rotational speed change suppression control amounts can be slightly changed.

The above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to claims of the present invention. FIG. 2 is a configuration diagram of a continuously variable transmission for a vehicle to which an embodiment of the present invention is applied. FIG. 3 is a control block diagram in the embodiment of FIG. 2. FIG. 4 is a diagram showing the relationship between the throttle valve opening and the target rotational speed. FIG. 5 is a diagram showing output torque characteristics with respect to engine rotational speed using the throttle valve opening as a parameter. 6, 7, and 8 are flowcharts each illustrating the operation of the embodiment of FIG. 2. FIG. 9 is a time chart showing the operation of the embodiment shown in FIG. FIG. 10, FIG. 12, and FIG. 13 are FIG. 6 in other embodiments of the present invention. 9 is a diagram corresponding to FIG. 3 and FIG. 9. FIG. 11 is a diagram showing the relationship between vehicle speed and suppressed rotational speed. 10: Engine 14: (Belt type) continuously variable transmission 56: Throat sensor (required load amount detection means) 60:
Rotation sensor (rotation speed detection means) 76: Target rotation speed determination means 78: Deceleration state determination means 86: Rotation speed change suppression means 90: Shift control control means Applicant: Toyota Motor Corporation 7 FIG.

Claims (1)

[Scope of Claims] A continuously variable transmission for a vehicle that continuously changes the rotation of an engine and transmits the same to wheels, comprising a rotation speed detection means for detecting the rotation speed of the engine, and a required load required for the engine. amount detecting means, target rotational speed determining means for sequentially determining a target rotational speed of the engine based on the required load amount from a predetermined relationship, A speed ratio control device comprising: speed ratio adjusting means for adjusting the speed ratio of the continuously variable transmission; deceleration state determining means for determining a deceleration state of the vehicle; and a predetermined time period after the start of deceleration of the vehicle. 2.
a rotational speed change suppressing means for suppressing a change in the rotational speed of the engine from the start of deceleration of the vehicle until the elapse of the predetermined time is determined by the timing means; A speed ratio control device for a continuously variable transmission for a vehicle, comprising: