JPH03121352A - Method of controlling continuously variable transmission - Google Patents

Abstract

PURPOSE:To surely prevent occurrence of a risk such as an engine rotational speed blow-up phenomenon or the like so as to allow the driver's intention to reflect upon rotational speed control by inputting a throttle opening degree and a vehicle speed so as to control the speed shift in order to change the final desired engine rotational speed. CONSTITUTION:The rate limit value during transient control is changed in accordance with a throttle opening degree and a vehicle speed which are delivered to a control section 28, and the throttle opening degree during transient control is changed in accordance with a vehicle speed. Accordingly, the longest time of the transient control is set in accordance with the throttle opening degree and the vehicle speed, and the final desired engine rotation speed during transient control is changed by the rate limit value, and accordingly, the control section 82 carries out suitable transient control which meets a vehicle running condition.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a continuously variable transmission control method, and in particular, when there is a change in the target engine speed consisting of the throttle opening and the vehicle speed while driving, The present invention relates to a continuously variable transmission control method that performs transient control using a rate limit value of , and performs speed change control to change the gear ratio.

[Prior Art] In a vehicle, a transmission is interposed between an internal combustion engine and drive wheels. This transmission changes the driving force and running speed of the drive wheels in accordance with the widely varying running conditions of the vehicle, thereby allowing the internal combustion engine to fully demonstrate its performance. The transmission includes a fixed pulley part fixed to the rotating shaft and a movable pulley part attached to the rotating shaft so as to be able to approach and separate from the fixed pulley part. There is a continuously variable transmission that transmits power by increasing or decreasing the rotation radius of a belt wrapped around a pulley by increasing or decreasing the width of the groove, thereby changing the speed ratio (belt ratio). Examples of this continuously variable transmission include, for example, JP-A-57-188856, JP-A-59-43249, and JP-A-59-7.
It is disclosed in Japanese Patent Application Laid-open No. 7159 and Japanese Patent Application Laid-open No. 81-233256.

In the rotation speed control of the continuously variable transmission, the final target engine rotation speed NESPF is changed by a rate limit value that is set to a constant value when the target engine rotation speed NFSPR changes during normal driving. However, when you change the driving mode while driving or when you press the throttle opening THR close to fully open, the final target engine speed N
Due to the large change in FSPF, a problem occurred that could not be addressed with the normal rate limit value.

For this reason, the applicant set the time rate of change to be larger than the predetermined time rate of change when changing the driving mode while driving or when the throttle opening THR is depressed close to fully open, thereby setting the final target engine speed. We have already completed an application for a rotation speed control device for a continuously variable transmission that improves the responsiveness of engine rotation speed by changing it (Japanese Patent Application No. 83-302733).

[Problems to be Solved by the Invention] By the way, in the conventional control method for a continuously variable transmission, transient control is started when the throttle opening THR exceeds a certain trigger value. Even when the opening degree THR slightly exceeds the trigger value, a phenomenon occurs in which the engine speed increases instantaneously.

For this reason, problems such as a phenomenon in which the engine speed rises occur, and the driver's driving intention is not reflected in the engine speed control, and the driver feels uncomfortable, which is disadvantageous in practice.

In addition, by setting and using a constant trigger value regardless of the vehicle's driving condition, the throttle opening THR is small in the low speed range, making it difficult to enter transient control, making it impossible to obtain sufficient transient effects. There is this inconvenience.

Furthermore, in high-speed ranges, the throttle opening THR is large, contrary to low-speed ranges, which causes the inconvenience of frequent transient control, which may result in more transient control being performed than necessary, which may worsen driving conditions. be.

[Object of the Invention] In order to eliminate the above-mentioned disadvantages, the object of the present invention is to change the final target engine speed by inputting the throttle opening degree and the vehicle speed (by providing a control unit that controls the speed change). The rate limit value during transient control is changed according to the throttle opening and vehicle speed input to the A continuously variable transmission control method in which the final target engine speed during transient control is set based on the speed and vehicle speed, and the final target engine speed during transient control is changed according to a rate limit value, and the control section can perform appropriate transient control that matches the driving state of the vehicle. It is in the realization.

[Means for Solving the Problem] In order to achieve this object, the present invention provides a mechanism for reducing the distance between the fixed pulley part and the movable pulley part attached to the fixed pulley part so as to be able to move toward and away from the fixed pulley part. The rotation radius of the belt wound around both pulleys is increased or decreased by increasing or decreasing the groove width of the belt, and if there is a change in the target engine speed made up of the throttle opening and vehicle speed while driving, a predetermined rate limit value is applied. In a continuously variable transmission control method that performs speed change control to change the speed ratio through transient control, the final target engine speed is changed by inputting a throttle opening degree and a vehicle speed (a control section for controlling the speed change is provided, and this control method is performed). The rate limit value during the transient control is changed according to the throttle opening degree and vehicle speed input to the section, and the throttle opening degree when performing the transient control is changed according to the vehicle speed, and the maximum time of the transient control is changed by the throttle control. The present invention is characterized in that it is set based on the opening degree and the vehicle speed, and the final target engine rotation speed during transient control is changed according to the rate limit value, thereby performing appropriate speed change control that matches the running state of the vehicle.

[Function] As described above, the invention changes the rate limit value during transient control according to the throttle opening and vehicle speed input to the control unit, and also changes the throttle opening when performing transient control depending on the vehicle speed. At the same time, the maximum time for transient control is set by the throttle opening and vehicle speed, and the final target engine speed during transient control is changed by the rate limit value.
The control unit performs appropriate transient control that matches the driving conditions of the vehicle.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

1 to 4 show embodiments of this invention. Fourth
In the figure, 2 is a belt-driven continuously variable transmission, 2A is a belt, 4 is a drive-side pulley, 6 is a drive-side fixed pulley part, 8 is a drive-side movable pulley part, 10 is a driven-side pulley,
12 is a fixed pulley piece on the driven side, and 14 is a movable pulley piece on the driven side. As shown in FIG. 7, the drive-side pulley 4 includes a drive-side fixed pulley piece 6 fixed to the rotating shaft 16.
and a drive-side movable pulley piece 8 mounted on the rotating shaft 16 so as to be movable in the axial direction of the rotating shaft 16 but not rotatable. Further, the driven pulley 10 also has a driven side fixed pulley piece 12 and a driven side movable bobbin piece 14, similarly to the driving side pulley 4.

First and second housings 18.20 are respectively attached to the driving side movable pulley piece 8 and the driven side movable boolean piece 14, and first and second hydraulic chambers 22.24 are respectively formed therein. Ru. At this time, a biasing means 26 made of a spring or the like is provided in the second hydraulic chamber 24 on the driven side to bias the second housing 20 in the direction of expansion of the second hydraulic chamber 24.

An oil pump 28 is provided on the rotating shaft 16, and the oil pump 28 is connected to the first and second hydraulic chambers 22,24.
The first oil passages 30 and 30 communicate with each other through second oil passages 30 and 32, and a primary pressure control valve 34, which is a speed change control valve, that controls a primary pressure, which is an input shaft sheave pressure, is interposed in the middle of the first oil passage 30. In addition, a line pressure (generally 5 to 25 kg/c
m2) to a constant pressure (3 to 4 kg/cm2), and a first three-way solenoid valve 42 for primary pressure control is connected to the primary pressure control valve 34 through a fourth oil passage 40. It goes through.

Further, a line pressure control valve 4 having a relief valve function for controlling the line pressure, which is the pump pressure, is disposed in the middle of the second oil passage 32.
4 is communicated through a fifth oil passage 46, and a second three-way solenoid valve 50 for line pressure control is communicated with this line pressure control valve 44 through a sixth oil passage 48.

Furthermore, a clutch pressure control valve 52 for controlling clutch pressure is installed in the seventh oil passage 5 in the middle of the second oil passage 32 on the side of the second hydraulic chamber 24 than the communicating portion of the line pressure control valve 44.
4, and a third direction solenoid valve 58 for clutch pressure control is connected to this clutch pressure control valve 52 through an eighth oil passage 56.
Communicate.

Further, the primary pressure control valve 34, the first solenoid valve 42 for primary pressure control, the constant pressure control valve 38, the sixth oil passage 48, the second solenoid valve 50 for line pressure control, and the clutch pressure control valve 52 are connected to a ninth oil The passages 60 communicate with each other.

The clutch pressure control valve 52 is communicated with the hydraulic start clutch 62 through a tenth oil passage 64, and a pressure sensor 68 is communicated with the tenth oil passage 64 through an eleventh oil passage 66. This pressure sensor 68 can directly detect the oil pressure when controlling the clutch pressure in hold and start modes, and contributes to the command to use the detected oil pressure as the target clutch pressure. Also,
Since the clutch pressure becomes equal to the line pressure in the drive mode, it also contributes to line pressure control.

An input shaft rotation detection gear 70 is provided on the outside of the first housing 18.
A first rotation detector 72 on the input shaft side is provided near the outer peripheral portion of the input shaft rotation detection gear 70. Further, an output shaft rotation detection gear 74 is provided on the outside of the second housing 20, and a second rotation detector 76 on the output shaft side is provided near the outer peripheral portion of the output shaft rotation detection gear 74. Detection signals from the first rotation detector 72 and the second rotation detector 76 are output to a control section 82, which will be described later, to determine the engine rotation speed and belt ratio.

The hydraulic start clutch 62 is provided with an output transmission gear 78, and a third rotation detector 80 for detecting the rotation of the final output shaft is provided near the outer periphery of the gear 78. In other words, this third
The rotation detector 80 detects the rotation of the final output shaft directly connected to the reduction gear, the differential, the drive shaft, and the tires.
Vehicle speed can be detected. Further, the second rotation detector 7
6 and the third rotation detector 80, the hydraulic starting clutch 6
It is also possible to detect rotations around 2, which contributes to detecting the amount of clutch slip.

Furthermore, various conditions such as the throttle opening of the vehicle's carburetor (not shown), engine rotation from the first to third rotation detectors 72.76.8 degrees, vehicle speed, etc. are input, and the duty ratio is changed to perform shift control. A control section 82 is provided, and the control section 82 controls the first three-way solenoid valve 42 and constant pressure control valve 38 for primary pressure control, the second three-way solenoid valve 501 for line pressure control, and the third three-way solenoid valve 58 for clutch pressure control. It is configured to control the opening/closing operation and also control the pressure sensor 68. Further, in detail, the functions of various signals and input signals input to the control section 82 are as follows: (1) Shift lever position detection signal... Each range signal such as Pl R1N1 Dl L etc. Required line pressure and ratio, clutch control, carburetor throttle opening detection signal...
Detects the engine torque from the memory input into the program in advance, determines the target ratio or target engine speed, detects the carburetor idle position, and improves accuracy in correction and control of the carburetor throttle opening sensor. , Accelerator pedal signal: Detects the driver's intention based on the state of depression of the accelerator pedal and determines the direction of control when driving or starting ■, Brake signal: Detects the driver's intention based on the state of depression of the accelerator pedal. Detects the presence and determines the control direction such as clutch disengagement■, Power mode option signal...It is used as an option to make the performance of the vehicle more sporty (or more economical).

The control unit 82 inputs the throttle opening degree and vehicle speed and performs speed change control to change the final target engine speed, and changes the rate during transient control according to the input throttle opening degree and vehicle speed. By changing the limit value and changing the throttle opening degree when performing transient control depending on the vehicle speed, the maximum time for transient control is set by the throttle opening degree and vehicle speed, and the final target during transient control is determined by the rate limit value. It has a configuration that changes the engine rotation speed and performs appropriate speed change control that matches the driving condition of the vehicle.

Specifically, the control unit 82 inputs the throttle opening THR of the carburetor (not shown) and the vehicle speed NCO, which is the clutch output rotation speed, and performs rate limit control, for example, in two types, from the normal rate limit control based on the rate limit value RLNR. The first and second rate limit values RLTR1 and R
First and second transient control THTR by LTR2
1, to be transferred to THTR2.

In other words, two maps, transient control box 1, second trigger curves TRCRV1 and TRCRV2, are set based on the throttle opening THR and vehicle speed NCO,
Throttle opening degree THR is set to predetermined first and second trigger values TH
First and second transient controls THTR1 and THTR2 corresponding to when one of TRG 1 and THTRG2 is exceeded.
This is what we do.

That is, the throttle opening THR and the first trigger value THT
RG 1 and 1st trigger curve TRCRV 1 (NGO)
The relationship is THR≧THTRG 1=TRCRVI
(NGO), the first transient control THTR1, which is throttle transient control, is performed, and the maximum time of the first transient control THTR1 is TTRIII based on the throttle opening THR and vehicle speed NCO.
Set to .

In addition, the throttle opening THR and the second trigger value THTRG
2 and the second trigger curve TRCRV2 (NCo) is THR≧THTRG2=TRCRV2 (NGO
), the second transient control THTR2 is performed, and the maximum time of the second transient control THTR2 is determined by the throttle opening THR and vehicle speed NCO.
Set to TRI2.

At this time, in the first trigger value THTRG1 and the second trigger value THTRG2, THTRGl<THTRG
The first transient control THTR1 is set in advance to satisfy the relationship 2, and the first transient control THTR1 is performed with a small throttle opening THR.

Note that the reference numeral 84 is a piston of the hydraulic start clutch 62;
86 is an annular spring; 88 is a first pressure coupler; 9
0 is a friction plate, 92 is a second pressure plate,
94 is an oil pan, and 96 is an oil filter.

Next, the effect will be explained.

As shown in FIG. 4, in the belt-driven continuously variable transmission 2, an oil pump 28 located on the rotating shaft 16 operates in response to the drive of the rotating shaft 16, and the oil is pumped into an oil pan 94 at the bottom of the transmission. is absorbed through the oil filter 96. The line pressure, which is this pump pressure, is controlled by the line pressure control valve 4.
4, the amount of leakage from this line pressure control valve 44,
In other words, if the amount of relief from the line pressure control valve 44 is large, the line pressure will be low, and if it is small, the line pressure will be high.

Next, electronic control of the belt-driven continuously variable transmission 2 will be explained.

Continuously variable transmission 2 is hydraulically controlled, and in response to commands from control unit 82, appropriate line pressure for belt retention and torque transmission, primary pressure for changing gear ratio, and clutch engagement are ensured. Clutch pressure is secured for each.

The explanation will be made along the control flowchart of the belt-driven continuously variable transmission 2 shown in FIG.

An engine rotation control program for the belt-driven continuously variable transmission 2 is started by driving an internal combustion engine (not shown) (
100), and the driving mode of the vehicle is set to drive mode (DR
V MODE) is determined (102).

Then, if this judgment (102) is YES, the first
The first trigger value THTRG1 is determined from the trigger curve TRCRVI (NGO), and the second trigger value THT is determined from the second trigger curve TRCRV2 (NGO).
RG2 is determined (104).

Further, if the above-mentioned judgment (102) is No, transient control is not performed, and therefore a transition is made to other control (not shown), for example, ratio control.

Next, throttle opening THR and second trigger value THTRG
2, the throttle opening THR and the second trigger value T
It is determined whether the relationship with HTRG2 is THR≧THRG2 (106).

If this determination (10B) is YES, 1 is subtracted from the second throttle opening trigger TTR2 to set it as the second throttle opening trigger TTR2 (108). If the determination (10B) is NO, the second throttle opening initial value TTRI2 is set as the second throttle opening trigger TTR2 (110).

The calculation process of the second throttle opening trigger TTR2 described above (
108), the second throttle opening trigger TTR2
A judgment (112) is made as to whether or not is O. This judgment (
If 112) is YES, it is determined whether the first throttle opening trigger TTR1 is 0 or not (114), and if the determination (114) is NO, the first throttle opening trigger TTR1 is determined. 1 is subtracted from 1 to obtain the first throttle opening trigger TTR1 (116).

After calculating the first throttle opening trigger TTR1 (116), the second rate limit value RLTR is calculated.
2 as the rate limit value RL (118), and
If the above judgment (114) is YES, the process (116)
) and moves on to processing (118).

Then, the final target engine speed of the previous control loop (
NESPF) Add the rate limit value RL to NESPRN to obtain the final target engine speed NFSPF (120
).

Further, after the calculation process (110) of the second throttle opening trigger TTR2 described above and when the judgment (112) is No, the throttle opening THR and the first trigger value THTRG
1, it is determined whether THR≧THTRG1 (122).

If the determination (122) is YES, the first throttle opening trigger TTR1 is obtained by subtracting 1 from the first throttle opening trigger TTRI, and 124L determines whether the first throttle opening trigger TTR1 is O or not. Judgment (
126).

If this judgment (128) is No, set the route limit value RLTR1 as the rate limit value RL (128)
Then, the process moves to the above-mentioned final target engine speed NESPF calculation process (120).

Further, if the above-mentioned judgment (122) is NO, the first throttle opening initial value TTRII is set as the first throttle opening trigger TTR1 (130). After this process (130) or if the above judgment (126) is YES, set the normal rate limit value RLNR of the normal rate limit control NRRL as the rate limit value RL 132)
Then, the process moves to the above-mentioned final target engine speed NFSPF calculation process (120).

Then, the target engine speed N by general ratio control
Calculate FSPRF (134).

Next, the target engine speed NE by general ratio control
The relationship between SPRF and the value obtained by adding one limit value RL to the final target engine speed (NESPF) NESPRN of the previous control loop is NESPRF≦NESPRN+R.
A judgment (13B) is made as to whether or not it is L.

If this determination (136) is YES, the target engine speed NESPRF by general ratio control is set as the final target engine speed NFSPF (138).

After the process (138), the final target engine speed NESPF is set to the final target engine speed (NESPF) NESPRN of the previous control loop (140), and if the above judgment (13B) is NO, the process ( 13
8) and sets the final target engine speed (NESPF) NESPRN of the previous control loop (14).
0).

Thereafter, the program returns (142).

Control of the belt-driven continuously variable transmission 2 will be explained with reference to FIG.

When the accelerator is depressed from a low throttle opening THR, for example, in a kickdown operation, the general ratio control controls the engine speed NE to the final target engine speed NESPF calculated by the schedule.

Also, the final target engine speed (N
ESPF) If there is a change in the target engine speed NFSPRF due to general ratio control with respect to NESPRN, rate limit control is performed when the system is equal to or higher than the rate limit value RL.

This rate limit control is performed between points a-f in FIG.

In other words, when the accelerator is depressed, the throttle opening THR
The relationship between THR and the first trigger value THTRG 1 is THR=T
Between points a and b, which is HTRG1, normal rate limit control NRRL is performed, and the relationship between throttle opening THR and second trigger value THTRG2 is THR=THTR.
The first transient control THTR1 is performed between points b and C until reaching G2.

The second transient control THTR2 is started from point C, and the target engine speed NFSP is set by general ratio control.
RF and the final target engine speed (N
ESPF) NESPRN with the second rate limit value RLT
The relationship with the value obtained by adding R2 is NESPRF≦NESPR
N+RLTR2, or time has elapsed by second throttle opening trigger TTRI2, or throttle opening THR
The relationship between THR and second trigger value THTRG2 is THR<TH
The process continues between points c and d unless TRG2 is reached.

After point d, the relationship between the target engine speed NESPRF by general ratio control and the value obtained by adding the th route limit value RLTR1 to the final target engine speed (NESPF) NESPRN of the previous control loop is NESPRF≦N.
ESPRN+RLTRI is not satisfied, and the relationship between throttle opening THR and first trigger value THTRG 1 is
Since THR≧THTRGI, TT from point b
The first transient control THTR1 is performed until point e, at which time RII has elapsed.

Furthermore, although the first and second transient controls THTRL THTR2 are not performed between points e and f, the target engine speed NESPRF by general ratio control and the final target engine speed NESPRF of the previous control loop
Rate limit control is performed because the relationship between ESPRN and the normal rate limit value RLNR does not satisfy NESPRF≦NESPRN+RLNR.

After point f, ratio control is performed based on a schedule.

Thereby, the rate limit value RL during transient control is changed to the first route limit value RLTR according to the throttle opening degree THR and vehicle speed NCO input to the control unit 82.
1 or a second rate limit value RLTR2,
By performing the first transient control THTRI or the second transient control THTR2, it is possible to reliably prevent problems such as a phenomenon in which the engine speed revs up, and the driver's driving intention can be reflected in the engine speed control. At the same time, there is no risk of giving a sense of discomfort to the driver, and fine grain control can be achieved, which is advantageous in practice.

Further, the throttle opening degree TH input to the control section 82
By setting and using the trigger value according to R and vehicle speed NCO, it is possible to avoid the situation where it is difficult to enter transient control in the low speed range, and it is possible to obtain a sufficient transient effect, as well as to avoid unnecessary transient control in the high speed range. There is no risk that the control will be carried out (driving performance can be improved).

Note that the present invention is not limited to the above-described embodiments, and various modifications can be made.

For example, in the embodiment of the present invention, the transient control is performed using two first and second transient control THTRIs.
, THTR2, and the relationship between the rate limit value and the longest transient control time was explained as a negative combination. However, it is also possible to set the relationship between the rate limit value and the longest time of transient control to perform three or more transient controls, and the relationship between the rate limit value and the longest time of transient control. Various combinations with time can also be set.

[Effects of the Invention] As explained in detail above, according to the present invention, there is provided a control unit that inputs the throttle opening degree and vehicle speed and performs speed change control to change the final target engine speed. The rate limit value during transient control is changed according to the throttle opening and vehicle speed, and the throttle opening when performing transient control is changed depending on the vehicle speed. By setting the rate limit value, the final target engine speed during transient control can be changed, and the control section can reliably prevent problems such as engine speed spikes, thereby changing the driver's driving intention. In addition to being able to reflect this in numerical control, it is possible to perform fine-grained control without causing any discomfort to the driver, and it is possible to perform appropriate transient control that matches the vehicle's driving conditions, making it practical for practical use. It's advantageous. In addition, by changing the rate limit value during transient control according to the throttle opening degree and vehicle speed input to the control section, it is possible to avoid a situation where it is difficult to enter transient control in a low speed range, and it is possible to In addition to obtaining a transient effect, there is no risk that transient control will be performed more than necessary in a high speed range, and driving performance can be improved.

[Brief explanation of drawings]

1 to 4 show embodiments of the present invention, FIG. 1 is a flowchart for controlling a belt-driven continuously variable transmission, FIG. 2 is a diagram illustrating engine rotation control of a belt-driven continuously variable transmission, FIG. 3 is a control block diagram of the belt-driven continuously variable transmission, and FIG. 4 is a block diagram of the belt-driven continuously variable transmission. In the figure, 2 is a belt-driven continuously variable transmission, 2A is a belt, 4 is a driving pulley, 10 is a driven pulley, 3
0 is the first oil passage, 32 is the second oil passage, 34 is the primary pressure control valve, 36 is the third oil passage, 38 is the constant pressure control valve, 40 is the fourth oil passage, 42 is the first three-way solenoid valve, 44 46 is the line pressure control valve, 46 is the fifth oil passage, and 48 is the line pressure control valve.
is the sixth oil passage, 50 is the second three-way solenoid valve, 52 is the clutch pressure control valve, 54 is the seventh oil passage, 56 is the eighth oil passage, 58 is the third three-way solenoid valve, 60 is the ninth oil passage, 62 is a hydraulic starting clutch, 64 is a 10th oil passage,
66 is an eleventh oil passage, 68 is a pressure sensor, 72 is a first rotation detector, 76 is a second rotation detector, 80 is a third rotation detector, and 82 is a control section.

Claims (1)

[Claims] 1. The radius of rotation of the belt wound around both pulleys can be increased by decreasing or increasing the groove width between the fixed pulley piece and the movable pulley piece that is attached to the fixed pulley piece so as to be able to move toward and away from the fixed pulley piece. In a continuously variable transmission control method, the transmission control method performs transient control using a predetermined rate limit value to change the gear ratio when there is a change in the target engine rotation speed made up of the throttle opening and the vehicle speed while driving. , a control unit is provided which inputs a throttle opening degree and vehicle speed and performs speed change control to change the final target engine speed, and adjusts the rate during the transient control according to the throttle opening degree and vehicle speed input to the control unit. The limit value is changed, and the throttle opening when performing the transient control is changed depending on the vehicle speed, and the maximum time of the transient control is set by the throttle opening and the vehicle speed, and the final target during the transient control is determined by the rate limit value. A continuously variable transmission control method characterized by changing the engine speed and performing appropriate gear change control that matches the driving condition of the vehicle.