JPS59219558A - Speed ratio control device for continuously variable transmission for car - Google Patents

Abstract

PURPOSE:To improve an efficiency of an acceleration by controlling a changing speed of a speed ratio to be adjusted at a fixed time after an acceleration stage is detected and then releasing a changing speed control to make a transit characteristic smooth when accelerating. CONSTITUTION:A target revolution speed is decided by a relation obtained in advance by a target revolution speed deciding means based on a requested load volume detecting signal having an engine revolution speed detecting means and an requested load volume detecting means. A speed ratio of a continuously variable transmission is adjusted by a speed ratio adjusting means based on a deviation between the target revolution speed deciding means and an actual revolution speed. At this time if an excess amount of the target revolution speed over the actual revolution speed reaches a fixed amount obtained in advance, the accleration state is detected by an acceleration state detecting means and by its output, the changing speed of the speed ratio adjusted by the above adjusting means is controlled for a fixed period thereafter. After the fixed period passes, it is controlled to allow the change of the changing speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a 4A speed ratio control system for a continuously variable transmission for vehicles that continuously changes engine rotation and transmits the same to a main shaft, and particularly relates to a technique for improving drivability during acceleration. It is something.

In 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 detects the rotation speed of the engine, and a required load detects the amount of required load required of the engine. target rotation speed determining means for determining a target rotation speed of the engine based on the required load amount from a predetermined relationship; A speed ratio control device has been proposed which includes a speed ratio adjusting means for adjusting the speed ratio of the continuously variable transmission. If such a speed ratio control device is used, the engine speed with the best fuel consumption rate will be selected depending on the driving condition of the vehicle. (acceleration) could not be obtained.

That is, if the rotational speed of the input shaft of the continuously variable transmission is Ni and the rotational speed of the output shaft is No, the following formula (1) holds true, and N
i −e = No −−−
(]l (where e is the speed ratio) If the rotational speed of the input shaft changes to Ni + ΔNi and the speed ratio changes to e + Δe after a predetermined time, then the rotational speed change ΔNo of the output shaft is calculated by the following formula (2). As in, ΔNo−ΔN1−e
+Ni−Δe−−−−−(2). In the acceleration state, the speed ratio e is decreased to increase the driving torque, so the change Δe becomes negative, and in the acceleration state of the vehicle, the second term on the right side of equation (2) becomes relatively large, and the acceleration performance is reduced. It will be the first time that it will be damaged. Therefore, if the target rotational speed of the engine corresponding to the operating position is determined by the acceleration operation, and the speed ratio of the continuously variable transmission is immediately changed so that the actual engine rotational speed matches the target rotational speed. , sufficient acceleration cannot be obtained.

The present invention has been made against the background of the above circumstances,
The purpose is to provide a speed ratio control device for a continuously variable transmission for a vehicle that provides sufficient drivability (acceleration performance) during acceleration operations.

In order to achieve such an object, the speed ratio control device of the present invention has the following features: (2) suppressing the rate of change in the speed ratio adjusted by the speed ratio adjusting means during a certain period after the acceleration state is detected by the acceleration state detecting means, and maintaining the same; The present invention is characterized in that it includes speed ratio change speed control means for allowing a change in the speed ratio change rate after a period of time has elapsed.

In this way, as shown in the complaint correspondence diagram of FIG. 1, when the acceleration state of the vehicle is detected by the acceleration state detection means and the acceleration state of the vehicle is detected by the speed ratio change speed detection means. For a certain period thereafter,
The rate of change in speed ratio is suppressed. Therefore, since the speed ratio change rate is suppressed in the initial state when acceleration operation is performed, the amount of increase in the second term on the right side of equation (2) is suppressed, ζ, and suitable drivability (acceleration) is achieved. You can get it. Moreover, since the rate of change in the speed ratio is suppressed only during a certain period at the beginning of the acceleration operation, the fuel economy, which is a characteristic of continuously variable transmissions, is hardly impaired as a whole. Here, the speed ratio is N O/N i, where Ni is the rotation speed of the input shaft of the continuously variable transmission and No is the rotation speed of the output shaft.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below based on the drawings.

In FIG. 2, a Held 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 Held 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.
A variable booby U 22 with a variable effective diameter attached to the 0, a conduction heald 24 hooked between the variable pulleys I8 and 22, and a groove width of the variable pulleys 18 and 22 are changed to create one effective thread. It is equipped with hydraulic cylinders 26 and 28 for changing the hydraulic pressure. Variable pulleys 18 and 22 are fixed rotary bodies 3 fixed to input shaft 16 and output shaft 20, respectively.
0 and 32, and movable rotary bodies 34 and 36, which are fixed to the input shaft 10 and the output shaft 20, respectively, so as to be able to move 1'iJ in the axial force direction and not to rotate about the axes,
By driving these movable rotating bodies 34 and 36 in the axial direction by hydraulic pressure applied to the spaces within the hydraulic cylinders 26 and 28, the hanging diameter (effective diameter) of the conduction heel I/24 is continuously changed. It looks like this. Then, line oil pressure is constantly supplied to the hydraulic cylinder 28, and the amount of hydraulic oil in the hydraulic minor cylinder 26 is adjusted by the speed ratio control valve 38.
The balance of forces acting on the movable rotors 34 and 36 is changed to change the speed ratio of the continuously variable transmission 14. Note that the pressure receiving area of the movable rotary body 34 (,;!: +iJ The dynamic rotary body 36 is also set to be large -ζ).

Furthermore, in the input shaft 16 and the output shaft 20, the movable rotary bodies 1'34 and 3 [) are fixed rotary bodies 30 and 32.
The arrangement in the axial direction opposite to G is made TI-Inijyong, and the twisting of the conduction heel I-24 is prevented.

The line oil pressure is obtained by hydraulic oil pumped from the oil tank 40 by the pump 42 and adjusted by the pressure regulating valve 44, and then passed through the oil line 46 to the -C shift control valve 38.
It is supplied to the hydraulic cylinder 28 and hydraulic cylinder 28. The pressure regulating valve 44 includes a linear solenoid I- driven by a pressure regulating signal SP to be described later, and a valve element driven by the linear solenoid I. Pressure regulation signal S I for release amount
) Adjust the line oil pressure by varying it according to

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. While adjusting the supply (pressure) of hydraulic oil to the hydraulic cylinder 26 by changing the flow surface u, 4.
8 and the return oil path 50 of the oil tank 40-\ to change the flow area,
Adjust the hydraulic oil discharge amount (pore pressure amount) in 6. That is,
In a state where the communication between the oil passage 48 and the oil passages 46 and 50 is cut off by the speed ratio control 11 valve 38 and the amount of hydraulic oil in the hydraulic cylinder 26 is kept constant, the speed ratio is fixed; 48 and the oil passage 46 are in communication, the hydraulic oil M in the hydraulic cylinder 26 is increased, the effective diameter of the iiJ variable pulley 18 is increased, and the effective diameter of the variable pulley 22 is decreased, The speed ratio is increased -υ''. Conversely, the speed ratio is decreased by bringing the oil passage 48 and the oil passage 50 into communication.

A throttle valve 54 connected to an accelerator pedal 52 is attached to the intake pipe of the engine IO.
The throttle signal TH, which is a voltage corresponding to the opening degree θ, is sent to the I10 boat 59 via the A/D converter 58 (Jt
be provided. Further, a rotation sensor 60 as a rotation speed detection means for detecting the rotation of the input shaft 16 and the output shaft 20 and a rotation sensor 62 as a vehicle speed detection means are respectively attached to the input shaft 16 and the output shaft 20. The rotation signal SR with the number of pulses corresponding to the rotation of the I/F
On the other hand, the rotation sensor 62 supplies the I/F circuit 64 with a rotation signal SC having a pulse number corresponding to the vehicle speed. The I/F circuit 64 converts the rotation signals SE and SC into a code signal representing the number of pulses per eye position time.
/'0 Supply to boat 59. The I10 boat 59 connects the ζCPU 66, RAM 68 . ROM
70, and the CPU 66 temporarily stores data in the RAM 68 according to the Progera J. stored in advance in the ROM 70.
! While utilizing the functions, the signal supplied to the 110 baud l~59 is processed, and the speed ratio signal SS that commands the speed ratio and its change rate is sent to the speed ratio via the D/A converter 7'2 and the drive circuit 74. While being supplied to the control valve 38 , a pressure regulating signal SP that commands the line hydraulic pressure to be zero is supplied to the pressure regulating valve 44 via the D/A converter 72 and the drive circuit 74 . The drive circuit 74 is a so-called power amplifier, which amplifies the power of the speed ratio signal SS and the pressure regulation signal SP outputted from the D/A controller 72 by a predetermined gain, and controls the speed ratio control valve 38 and the pressure regulation signal SP. It supplies the linear solenoid of the regulating valve 44.

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

In block 76, a target rotational speed of the engine 10 (target rotational speed of the input shaft 16) Ni' is calculated based on the throttle valve opening θ from a predetermined relationship. The target rotational speed Ni' is a value determined so that the required horsepower corresponding to the throttle valve opening θ can be obtained at the minimum fuel consumption rate. Then, in block 78, it is determined whether the deviation E (-Ni'-Ni) between the target rotational speed Ni' and the actual rotational speed Ni exceeds a predetermined value. Speed ratio e during the subsequent fixed period T
The limit value of the speed of change of is determined, and the speed ratio e and its speed of change &
is sent to the speed ratio control valve 38 via the feed bank gain 80 and the drive circuit 74. As a result,
The amount of hydraulic fluid (hydraulic pressure) in the hydraulic cylinder 26 on the input side of the continuously variable transmission 14, that is, the speed ratio C, is controlled by the speed ratio control valve 38.
is changed so that the actual rotational speed Ni matches the L1 reference rotational speed Ni'. On the other hand, in block 82, the engine IO
The output torque Te is calculated based on the throttle valve opening θ and the actual rotational speed Ni, and in block 84, the calculated output torque Te and the ITJ transmission change speed N are calculated.
The optimum line oil pressure P is calculated based on the rotation speed No of the output shaft 2o corresponding to i and the vehicle speed, and a signal representing the line oil pressure P is supplied to the pressure regulating valve 44 via the drive circuit 74. As a result, the line oil pressure P is maintained at the minimum pressure within the range where torque transmission loss of the transmission heald 24 does not occur due to slipping, etc., and power loss and durability reduction of the transmission heald 24 due to excessive line oil pressure are prevented. has been done.

The operation of this embodiment will be explained below according to the flowchart of FIG.

First, step S1 is executed, and the opening degree θ of the throttle valve 54, the actual rotational speed Ni of the engine 10, and the rotational speed No. of the output shaft 20 corresponding to the vehicle speed are read according to the signals TH, SP, and SC, and are stored in the RAM 68. be remembered.

Then, step S2 as a target rotational speed determination means is executed, and from the predetermined relationship, the target rotational speed Ni' is calculated based on the throttle valve opening θ, and the actual speed ratio e (No/Ni ) is calculated. Also,
Step S3 is executed, and the deviation E between the target rotational speed Ni' and the actual rotational speed Ni is calculated.

Then, step S5 of forming a speed adjustment means to be described later.
Prior to execution of the speed ratio control routine from S13 to S13, a speed ratio change speed & control routine S4 is executed. As shown in FIG. 5, in step SRI as the acceleration state detection means, the deviation E between the target rotation speed Ni' and the actual rotation speed N3i is larger than a predetermined constant value A. If it is large, the accelerator pedal 52 is
Since the manipulated variable is relatively large and the vehicle is in an acceleration state, steps SR2 and subsequent steps are executed. ” The constant value A is determined in this way. In step SR2, a timer TI is set and starts timing, and
In step SR3, it is determined whether the content of the timer TI is smaller than a predetermined constant time T.

If the content of the timer TI is smaller than a preset constant time T, in other words, in the initial state before the time 'F has elapsed after the acceleration state has been determined, step S R4 is executed and the speed is determined. The ratio change rate e is fixed at zero. That is, Δe in steps S7 and SIO, which will be described later, is set to zero, and the target speed ratio e' is fixed.

That is, steps SR2 to SR4 form a speed ratio change speed control means.

If the deviation E is not larger than a predetermined constant value in step SRI mentioned above, and if the content of timer T1 exceeds the preset time T in step SR3, Factor 5: The acceleration state of the vehicle is gradual, so step SR5
and SR6 are executed. In step SR5, the contents of the sub-timer 'I'1 are reset to zero, and in step SR6, the contents of '(speed ratio change speed &) are set to a predetermined constant value X. It is set to a relatively large constant value so that Δe in S7 and S10 can be obtained from the original speed ratio change rate X. Therefore, when the series of steps in FIG. 4 are repeatedly executed at high speed, As shown in Figure 6, the rate of change e is at the time 1 when the acceleration state of the vehicle is detected.
It is suppressed (fixed) to zero within a certain period after 3, and after that period, the speed ratio change rate X is set to the normal speed ratio change speed X.

Returning to FIG. 4, it is determined in step S5 whether the deviation E is positive, negative, or zero, and if it is zero, step S6 is executed and the content of the keyaki speed ratio e' is will be maintained as is. Furthermore, the speed ratio C' in the initial state is the actual speed ratio e.
It is said that If the deviation E is positive in step S5, a small value Δe of - 1 predetermined as the content of the speed ratio e' is set.
is added. Then, in step S)), it is determined whether the content of the target speed ratio e' exceeds the maximum value emax, and if it does, step S9 is executed and the content of the express power ratio e' becomes the maximum value. limited to e maX. On the other hand, if the deviation E is negative in step S5, step SiO is executed, and a predetermined small value Δe is subtracted from the contents of the target speed ratio e'. Then, in step Sit, it is determined whether the target speed ratio e' is smaller than the minimum value emin, and if it is, step S2 is executed to limit the content of the target speed ratio e' to the minimum value. .

Once the target speed ratio e' is determined as described above, step S13 is executed to calculate the deviation between the target speed ratio e' and the actual speed ratio C, and to calculate the deviation between the target speed ratio e' and the actual speed ratio C. A control amount (foot hack gain) F is calculated by multiplying by a constant K, and the hydraulic oil field in the hydraulic cylinder 26 is changed with a flow rate corresponding to the control amount F to follow e or e'. I get kicked. That is, when the difference between the target speed ratio e' and the actual speed ratio e is zero, the control amount F is zero, so the operating position of the speed ratio control valve 38 is considered to be neutral pleasure, and the pressure inside the hydraulic cylinder 26 is Although the amount of hydraulic oil is kept constant and the speed ratio e is not changed, for example, if the target speed ratio e' is larger than the actual speed ratio e, the hydraulic oil in the hydraulic cylinder 26 is increased and the speed is increased. While the ratio e is increased, the target speed J:1. e'
is smaller than the actual speed ratio, the hydraulic cylinder 26
The amount of hydraulic oil (hydraulic pressure) in the engine is decreased, and the speed ratio e is decreased. Therefore, the speed ratio e is adjusted so that the deviation E between the target rotational speed Ni' and the actual rotational speed Ni becomes zero.

Next, step S14 is executed, and the rotational torque Te of the engine 10 is calculated from the throttle valve opening degree θ read in step S1 and the actual rotational speed Ni based on the predetermined relationship. S ] 5, the jljl control key (■) for adjusting the line oil pressure is determined in advance based on the 1-luke 'I' e calculated in step 514 and the rotational speeds Ni and No read in step S1. The function equation [(θ, Ni, N.

) is calculated according to This control 1) is the conduction held 2
The line oil pressure is set so that sufficient line oil pressure can be obtained within a range that does not cause slippage.

Then, since the pressure regulation signal S I-) corresponding to the control amount P is supplied to the pressure regulation valve 44, the pressure regulation valve 44 regulates the line oil pressure to an optimal value.

As described above, according to the present embodiment, in the vehicle, the horn speed ratio change speed e in the initial state within a certain period after the acceleration state is detected is suppressed to zero (
(fixed), the increase in the second term on the right-hand side of equation (2) above is suppressed, and suitable acceleration performance is obtained, while the fuel efficiency, which is a characteristic of continuously variable transmissions, is almost completely lost. There is no.

Next, other embodiments of the present invention will be described. Incidentally, the same reference numerals are given to the parts common to those of the above-mentioned embodiment, and the explanation thereof will be omitted.

As a method of suppressing the speed ratio change rate & during a certain period T after the acceleration state is detected, it is not uncommon to fix the speed ratio change rate & to zero, but to maintain a constant amount of change over time. It is also possible to change it by

That is, step SR4 in FIG. 5 may be replaced with step SR4' in FIG. 7. In step SR4', a function r (t) that changes at a constant rate of change with time t is stored, and this function contains the time after the acceleration state is detected, in other words, the timer T
By sequentially substituting the contents of I, the speed ratio change speed &
is obtained as shown in FIG.

According to this embodiment, in addition to obtaining the same effect as the above-mentioned embodiment, there is no sudden change in the speed ratio change speed & after the timer TI expires, so that when the continuously variable transmission 14 accelerates. It has the advantage of having smooth transient characteristics.

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

For example, although the above-mentioned embodiment has been described based on the 4J Held type continuously variable transmission 14, 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, The intake air of the tube may be the same.

In short, any amount that represents the required load meter of the engine 10 may be used.

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 of the embodiment of FIG. 2. 4 and 5 are flowcharts 1 to 0 explaining the operation of the embodiment of FIG. 2. FIG. 6 is a time chart explaining the operation of the embodiment shown in FIG. FIGS. 7 and 8 are a flowchart I and a time chart respectively explaining the operation of another embodiment of the present invention. 10: Engine 14: (Bell I type) continuously variable transmission 56: Throttle sensor (required load detection means) 60:
Rotation sensor (rotational speed detection means) Step S2 (target rotational speed determination means) Steps S5 to 513 (speed 1 adjustment means) Step 5RI (acceleration state detection means) Applicant: Toyota Motor Corporation 1 JP-A-59-219558 ( 8) Ryu 7 Zuuta・1 Bi Invasion #l Sui Banjo (・Φ)

Claims (3)

[Claims] (1) In a continuously variable transmission for a vehicle that continuously changes the speed of the engine and transmits it to the wheels, there is a rotation speed detection means for detecting the rotation speed of the engine and a required load amount required for the engine. a target rotation speed determining means for determining a target rotation speed of the engine based on the required load amount from a predetermined relationship; and a speed ratio adjusting means for adjusting the speed ratio of the continuously variable transmission so as to match the speed ratio of the continuously variable transmission, the speed ratio control device comprising: a speed ratio adjusting means for adjusting the speed ratio of the continuously variable transmission so as to match the target rotational speed of the engine; a first stage of acceleration state detection for detecting the acceleration state of the vehicle when the acceleration state of the vehicle reaches a predetermined constant amount; Speed ratio change speed control means for suppressing the change speed of the speed ratio adjusted by the ratio adjustment means and allowing the change speed of the speed ratio to change after the elapse of the specified period. Speed ratio control device for continuously variable transmissions for vehicles. (2) The speed ratio change j* degree control means fixes the speed of change of the speed ratio to zero during the constant light period after the acceleration state of the vehicle is detected. 4. Speed ratio control device for continuously variable transmission for vehicles. (3) A patent in which the first stage of speed ratio change speed control gradually changes the speed of change of the speed ratio over time during the fixed period after the acceleration state of the vehicle is detected. A speed ratio control device for a continuously variable transmission for a vehicle according to claim 1.