JPH01153857A - Control method for continuously variable transmission of vehicle - Google Patents

Abstract

PURPOSE:To improve the driving feeling of a vehicle and safety in a gear change control based on the operating condition of a driver by making the changing speed of gear ratio lower as compared to that in an ordinary gear change control at the time of detecting the fatigue condition of the driver. CONSTITUTION:A controller 54 receives the signals of a vehicle speed SV, a throttle opening Stheta, the rotating speeds SP1, SP2 of an input shaft 16 and an output shaft 24, an engine speed SNE, a shift lever position SP, a steering angle SD, etc., to control the gear ratio of a continuously variable transmission 14 based on the operating condition of a driver. In this gear change control, when the fatigue condition of the driver is detected from a zigzag driving condition, the frequency of stepping of an accelerator pedal, etc., oil pressure control valves 72, 74, 76, 77, etc. for controlling the changing speed of gear ratio are switched over in the direction of making the changing speed lower or a gear change pattern is changed to make the changing speed of gear ratio lower as compared to that at the time of ordinary gear change control. Thereby, the driving feeling of a vehicle and safety can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a technology for controlling the gear ratio of a continuously variable transmission mounted on a vehicle.

[Prior Art] Conventionally, a technology has been disclosed that detects a driver's drowsy state from brain waves (α waves), pulse rate, etc., or detects from the frequency of meandering driving of the vehicle, etc., and issues a warning such as "rest". (Refer to Japanese Utility Model Application No. 56-73638).

In addition, the speed change control of a continuously variable transmission installed in a vehicle detects, for example, the depression speed of the accelerator pedal as the operating state of the driver, and changes the speed of change of the gear ratio depending on the degree of this depression speed. We are working to improve the acceleration and sense of speed.

[Problems to be Solved by the Invention] However, as in the conventional technology, a drowsy state is detected based on the physiological effects of the driver or the driving state of the vehicle, Merely issuing a sound to warn a drowsy driver cannot prevent the driver from accumulating fatigue or from feeling an unexpected sense of acceleration when the driver is fatigued.

This is because the conventional technology does not take into account changes in driving sensation due to driver fatigue, as described below. In other words, for example, if the driver is fatigued after driving for a long time, the driver's pressure on the accelerator pedal will
Even if the gear ratio of the continuously variable transmission changes in the same way as normal, the driver feels that the vehicle has accelerated more than requested, and this may increase fatigue as the driver tries to control this change in the vehicle's behavior. There was a thunderstorm.

An object of the present invention is to improve the driving feeling and safety of a vehicle by solving the above problems.

[Means for Solving the Problems] As a means for achieving the above object, a method for controlling a continuously variable transmission for a vehicle according to the present invention provides a control method for a continuously variable transmission mounted on a vehicle, as illustrated in FIG. In the method of controlling the gear ratio of a transmission based on at least the operation state of the driver of the vehicle, the speed change control based on the operation state of the driver (steps SB, SC) includes detecting the fatigue state of the driver. (step SA), the change speed of the gear ratio is made slower (step SB) than during normal gear change control.

A continuously variable transmission mounted on a vehicle is a transmission that uses, for example, a belt or a bearing to continuously control a gear ratio based on instructions from, for example, a computer.

The driver's fatigue state can be detected by detecting, for example, the state of meandering driving,
Vehicle operation status and brain waves determined from the frequency and speed of accelerator pedal depression.

This is done based on the state of physiological phenomena such as pulse rate.

Normal gear shift control refers to controlling the gear ratio of a transmission, based on at least the amount of accelerator pedal depression, in order to maintain good fuel efficiency during steady driving and to improve acceleration performance when accelerating. be.

Slowing down the rate of change in the gear ratio means, for example, switching a valve that controls the rate of change in the gear ratio of a hydraulic continuously variable transmission, such as a flow control valve or a hydraulic control valve, to one that slows down the rate of change in the gear ratio. Alternatively, for example, the shift pattern for obtaining the target gear ratio from 1.6 seconds of accelerator depression may be changed to one in which the gear ratio changes less than usual even if the amount of accelerator depression changes.

[Operation] In the control method for a continuously variable transmission for a vehicle according to the present invention, when the fatigue state of the driver of the vehicle is not detected (step SA),
, the gear change control is performed based on at least the operating state of the driver during normal times (step SC), and when a fatigue state is detected (step SA), the operating state is changed to a state where the change rate of the gear ratio is slower than normal. The original speed change control is performed (step 3B).

Note that, as a method of slowing down the speed of change of the gear ratio, it may be done, for example, by controlling the engagement port (or speed ratio of the clutch) of the clutch connected to the continuously variable transmission (by increasing clutch slippage). Alternatively, the engine output may be controlled (reduced).

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

In FIG. 2, a vehicle engine 10 is connected to an input shaft 16 of a continuously variable transmission 14 via a fluid coupling 12 with a direct coupling clutch 11. The input shaft 16 has
The V-groove width, ie the transmission belt 2, is controlled by the hydraulic cylinder 18.
A variable pulley 22 is provided whose diameter of 0 is changed. The output shaft 24 is provided with a variable pulley 28 whose V-groove width is changed by a hydraulic cylinder 26 . Therefore, the rotational force transmitted to the input shaft 16 is transferred to the variable pulley 22.
It is transmitted to the output shaft 24 via the transmission belt 20 wound around the transmission belts 28 and 28, and is also transmitted to the sub-transmission 30 at the subsequent stage. The sub-transmission 30 includes a first sun gear 32. Second
Sungear 34. It is equipped with a Ravignaux-type compound planetary gear device consisting of a ring gear 36, etc., and a high-speed clutch 38. Low speed brake 40. By selectively operating the reverse brake 42 by a hydraulic actuator (not shown), the gear ratio Rf of the auxiliary transmission 30 is switched, or forward rotation and reverse rotation are switched, as shown in Table 1 below. It has become.

Table 1 Here, in Table 1, ρ1 is ZSI/Zr and ρ2 is Z
S2/Zr. However, ZSI is the number of teeth of the first sun gear 32, ZS2 is the number of teeth of the second sun gear 34, and Zr is the number of teeth of the ring gear 36. Belt type continuously variable transmission 14
The output shaft 24 of the auxiliary transmission 30 constitutes an input shaft of the auxiliary transmission 30, and the carrier 44 supporting the planetary gear in the auxiliary transmission 30 constitutes an output shaft, so the gear ratio of the auxiliary transmission 30 is set to the carrier 4.
The value is obtained by dividing the rotation speed of the output shaft 24 by the rotation speed of 4. The rotational force transmitted to the carrier 44 is transmitted to the intermediate gear 46,
48 and final deceleration @ 50, the pair of drive wheels 5 of the vehicle
2, respectively.

In the vicinity of the variable pulleys 22 and 28, an input shaft rotation speed sensor 58 and an output shaft rotation speed sensor 60 are provided for outputting pulse signals SP1 and SF3 of frequencies corresponding to the rotation speeds of the variable pulleys 22 and 28 to the controller 54. is provided. A vehicle speed sensor 61 is provided near the intermediate gear 48 for outputting a pulse signal SV of a frequency corresponding to the rotation speed of the intermediate gear 48 to the controller 54. A throttle valve 62 provided in the intake pipe of the engine 10 is opened and closed by operating an accelerator pedal.The throttle valve 62 is provided with a throttle sensor 64, and the throttle valve opening θ is detected from the throttle sensor 64. A throttle signal Sθ representing the above is supplied to the controller 54. An engine rotation speed sensor 65 is provided in the ignition circuit of the engine 10, and a rotation speed signal SNE representing the engine rotation speed Ne is supplied from the engine rotation speed sensor 65 to the controller 54.

In this embodiment, a shift lever is used as a shift switching device.
66 is used, and the operation position sensor 68 detects the operation position of the shift lever 66.
A signal SP representing the shift operation position Psh of 66 is supplied to the controller 54.

This shift lever 66 is mechanically associated with a manual valve in the hydraulic circuit 70, and when operated to the neutral range, the high speed clutch 38. Low speed brake 40. Hydraulic pressure is prevented from being supplied to any of the hydraulic actuators for operating the reverse brakes 42, but when the reverse range is operated, hydraulic oil is supplied only to the hydraulic actuators that operate the reverse brakes 42. let Also, the shift lever
When 66 is operated in the normal driving range of the forward range (D=nidry range), it allows hydraulic oil to be supplied only to the hydraulic actuator that operates the high-speed clutch 38, and the high-speed gear be maintained.

Also, the shift lever 66 is in the automatic shift range (S range) of the forward range or the engine brake range (L range).
range), the high speed clutch 38
Also, hydraulic oil is allowed to be supplied to any of the hydraulic actuators that actuate the low-speed brake 40. Hydraulic pressure is alternatively supplied to these hydraulic actuators from a shift valve that operates in response to the operation of a shift electromagnetic valve 72 provided in the hydraulic circuit 70.

The hydraulic circuit 70 supplies line hydraulic pressure regulated in accordance with the actual gear ratio of the continuously variable transmission 14 and the output torque of the engine 10 to the hydraulic cylinder 26 provided on the output shaft 24, and control the tension as necessary and sufficient. Further, the hydraulic circuit 70 supplies or discharges hydraulic oil to the hydraulic cylinder 18 provided on the input shaft 16 in response to the operation of the shift direction switching valve 74, and also responds to the operation of the shift speed switching valve 76. The flow rate of the hydraulic oil into the hydraulic cylinder 18 or the hydraulic oil discharge rate from the hydraulic cylinder 18 is changed, and the direction of the hydraulic oil to the direct coupling clutch 11 is switched in response to the operation of the lock-up switching valve 77.

Said shift direction switching valve 74. The operation of the shift speed switching valve 76 and the lock-up switching valve 77 is controlled by the controller 54, and the shift direction switching valve 74 is controlled by the continuously variable transmission 14.
control to increase or decrease the gear ratio of
The shift speed switching valve 76 controls the changing speed of the gear ratio, and the lockup switching valve 77 controls the amount of engagement (transmission torque) of the direct coupling clutch 11.

The hydraulic pump 78 is driven by the engine 10 or the like to force-feed the hydraulic oil in the oil tank 80 to the hydraulic circuit 70, and functions as a hydraulic source for the hydraulic circuit 70.

A steering column (not shown) of the vehicle is provided with a steering angle sensor 81 made of a photointerrupter or the like, and a steering angle signal SD representing the steering angle θd is supplied to the controller 54.

The controller 54 has an input/output interface 82 .
Central processing unit 84. and a storage section 86, etc., and the storage section 8
According to the program and data stored in advance in 6,
By processing various input signals inputted through the input/output interface 82 and controlling the operation of the shift solenoid valve 72 based on the processing results, the gear stage of the sub-transmission 30 is automatically shifted. By controlling the operation of the shift direction switching valve 74 and the shift speed switching valve 76, the gear ratio of the continuously variable transmission 14 is changed to an optimum value, and by controlling the operation of the lockup switching valve 77, the direct coupling clutch 11 is changed. Lock-up ``on'' or lock-up ``on''
Turn off.

Next, the gear ratio control routine of this embodiment, which is executed every predetermined time (here, 8 m5ec), will be explained with reference to the flowchart of FIG.

FIG. 3 shows a control routine for controlling the gear ratio of the entire transmission of the vehicle. First, the vehicle speed v1, the throttle opening θ, the rotation speed Nin of the input shaft 16,
The rotational speed Nout of the output shaft 24, the engine rotational speed Ne, the operation position 11Psh of the shift lever 66, and the steering angle θd are determined by the signals SV, Sθ, SP1°SP2. Read based on SNE, SP, and SD (step 100). Next, it is determined whether the actual operating position of the shift lever 66 is the normal driving range or the automatic shift range (step 110).
. If it is determined that the driving range is normal, the transmission ratio control routine in the normal driving range shown in FIG. control (step 120).

On the other hand, if it is determined that the shift lever 66 has been controlled to the automatic shift range (step 110), shift control of the sub-transmission 30 is executed (step 130). That is, the gear position of the auxiliary transmission 30 is determined based on the vehicle speed ■ and the throttle opening θ from the shift pattern stored in advance in the storage unit 86, and the shift solenoid valve is adjusted so that the determined gear position is achieved. A drive signal is output to 72. The shift pattern is shown in FIG. 5, for example, and is stored in the form of a data map or the like. In the figure, U1
2 is an upshift line prepared in consideration of the driving performance of the vehicle, and is used to judge the upshift from a low gear (1st gear) to a high gear (2nd gear). 21 in the figure is prepared in order to form an appropriate hysteresis and in consideration of the acceleration performance due to kickdown, and is provided in order to create an appropriate hysteresis and to take into account the acceleration performance due to kickdown, and is used for downshifting from a high-speed gear to a low-speed gear. This is the downshift line used for judgment.

Next, it is determined whether the actual gear position of the sub-transmission 30 is a high speed gear position or a low speed side gear position (step 140). If it is determined that the gear is on the high speed side, for example, instead of the speed ratio control routine (step 120) in the normal driving range shown in FIG. 4, a speed ratio control routine for the high speed gear, the details of which are not shown, is activated. and executes gear ratio control of the continuously variable transmission 14 (step 1
50).

If it is determined in step 140 that the gear stage of the auxiliary transmission 30 is the low speed gear stage, for example, the fourth
Instead of the gear ratio control routine for opening the normal running range (step 120), details of which are shown in the figure, a gear ratio control routine for a low gear stage, the details of which are not shown, is activated to execute the gear ratio control of the continuously variable transmission 14. (Step 160).

Next, the gear ratio control routine in the normal running range shown in FIG. 4 will be explained. In the control routine shown in FIG. 4, first, based on the state of change in the steering angle θd, it is determined whether the vehicle is meandering due to the fatigue state of the driver (step 210). Meandering driving is determined when the steering wheel is kept at a slight angle with respect to straight forward movement for a predetermined period of time or more, and this is repeated for a predetermined number of times or more. If it is determined that the meandering operation is not currently in the meandering operation state, the memory unit 8
6, the target rotational speed Nin'' data map for the normal running range shown by the solid line in FIG. 6 is set in the work area in the RAM of the storage unit 86 (
Step 220). - On the other hand, if it is determined that the current meandering operation state is present, the throttle opening θi is lower than the normal state as shown by the two-dot chain line in FIG. A data map of the target rotational speed Nin for the normal running range during fatigue that provides the target rotational speed Nin* of is set in the work area in the RAM of the storage unit 86 (step 230). After setting the target rotation speed data map in the work area, next calculate the target rotation speed N10 by referring to the target rotation speed Nin data map stored in the work area, and proceed to step 100 in FIG. Read vehicle speed vi, (i=o~m
ax) and the throttle opening θ (step 240). After calculating the target rotational speed N10, control to actually change the gear ratio of the continuously variable transmission 14 is performed (steps 250 to 270). . That is, first, it is determined whether the target rotational speed Nin'' is less than or equal to the rotational speed Nin of the input shaft 16 (step 250).

Next, if Nin'>Ni, it is determined that it is time to increase the rotational speed Nin of the input shaft 16, and control to increase the shift (downshift control) is executed (step 26
0). On the other hand, when the target rotational speed Nin* is smaller than the rotational speed Nin of the input shaft 16, the gear ratio γ of the continuously variable transmission 14
(step 270).

By executing steps 210 to 270, the gear ratio of the continuously variable transmission 14 when the shift lever 16 is in the normal driving range is changed to the normal speed ratio shown by the solid line in FIG. 6 when the vehicle is not meandering. The target rotation speed Nin' for the travel range is determined based on the data map and is actually controlled.

On the other hand, if it is determined that the meandering operation is occurring, the determination is made based on the "Nin" data map shown by the two-dot chain line in FIG. 6, and actual control is performed.

Therefore, during meandering driving due to driver fatigue, the actual gear ratio of the continuously variable transmission 14 is determined from the normal speed ratio determined from the current vehicle speed V and the throttle opening θ, as shown by the two-dot chain line in FIG. The speed increasing ratio is controlled based on a lower target rotational speed Nin* (for example, 20 to 50% lower Nin'' when the throttle opening θ is 100%). Meandering operation is similarly determined in the gear ratio control in the high gear stage (step 150) and the gear ratio control in the low gear stage (step 160), and when fatigue occurs, the actual gear ratio is controlled based on the gear change pattern of speed increase. As explained above, according to this example,
When the vehicle is driving in a meandering manner due to driver fatigue, the continuously variable transmission 14 rapidly decelerates even if the throttle opening θ, which corresponds to the state of depression of the accelerator pedal, changes rapidly or greatly. The gear is no longer shifted to the ratio side (downshift side), and sudden acceleration due to this is prevented. As a result, when the driver is fatigued, smoother driving performance and driving sensation can be obtained than under normal conditions, which has the extremely excellent effect of reducing driver fatigue by preventing the driver from feeling any sudden changes in behavior. play.

Next, a second embodiment will be explained. In this embodiment, as performed in steps 210 to 230 of the routine of FIG. 4 of the first embodiment, when fatigue occurs, the target rotation speed Nin for fatigue
”Instead of setting the map, step 260,
The downshift speed or upshift speed in the downshift processing or upshift processing of the H.270 is directly controlled.

When the downshift processing routine shown in FIG. 7 is started, it is determined whether or not the meandering operation is being performed, as in the first embodiment (step 300). A normal time change speed map (not shown) is set in the work area (step 310).

This map has a temporal characteristic as shown by the solid line in FIG.
Shift speed switching valve 76 that shifts from 1 to Nin2
This gives the valve an open state.

On the other hand, if the current meandering operation is in progress, fatigue gives rise to aging characteristics in which the change rate of the gear ratio γ is slower (for example, 50 to 100% slower) than in normal conditions, as shown by the two-dot chain line in Figure 8. A time-varying velocity map is set in the work area (step 320).

After setting the above map, next shift direction switching valve 7
4 to the downshift side (step 330),
Next, the opening state of the shift speed switching valve 76 is controlled based on the map set in the work area, and in accordance with the throttle opening θ, the elapsed time, etc. (step 340).

It should be noted that during upshifting, control is performed based on the meandering state in the same way as during downshifting.

Therefore, during meandering driving due to driver fatigue, the rate of change of the gear ratio based on the accelerator depression speed becomes slower than in normal times.

As described above, similar to the first embodiment, the second embodiment reduces the accumulation of fatigue of the driver when the driver is fatigued and improves safety. It has an extremely excellent effect that it can be applied to a type of control that does not use an electronic control circuit. In addition,
The present invention is not limited to the above-mentioned embodiments; for example, as a method of changing the speed of change of the gear ratio, the engagement state of the fluid coupling of the transmission or the direct coupling clutch of the torque converter may be controlled; As a method of detecting a fatigue state, a method of detecting and determining physiological phenomena such as brain waves and pulse rate may be used.

Further, even if the transmission is a stepped type, the present invention may be applied and controlled as long as the gear ratio is controlled in the same way as a continuously variable transmission.

[Effects of the Invention] The control method for a continuously variable transmission for a vehicle according to the present invention, when a driver's fatigue state is detected, slows down the change speed of the gear ratio compared to normal times, thereby preventing fatigued driving. This eliminates the possibility of changes in the behavior of the vehicle due to sudden sudden acceleration, for example, that would increase driver fatigue.

As a result, the driving safety of the vehicle is improved due to the effect of reducing driver fatigue, and the driving window is also improved, which is an extremely excellent effect.

[Brief explanation of the drawing]

FIG. 1 is a flowchart illustrating the basic configuration of the present invention, FIG. 2 is a configuration diagram of a system to which an embodiment of the present invention is applied, FIG. 3 is a flowchart of the gear ratio control routine of the embodiment, and FIG. Figure 5 is a flowchart of the gear ratio control routine in the normal driving range; Figure 5 is a graph showing the gear change characteristics of the sub-transmission of the embodiment; Figure 6 is a graph showing the gear change characteristics of the continuously variable transmission of the embodiment; FIG. 7 is a flowchart of the downshift processing routine of the second embodiment, and FIG. 8 is a graph showing the change characteristics of the input shaft rotation speed. 10...Engine, 14...Continuously variable transmission, 30...
・Sub-transmission, 54... Controller, 81... Steering angle sensor

Claims (1)

[Claims] In a method for controlling the gear ratio of a continuously variable transmission mounted on a vehicle based on at least the operating state of the driver of the vehicle, the shift control based on the operating state of the driver includes: A control method for a continuously variable transmission for a vehicle, characterized in that when a fatigue state of a person is detected, the speed of change in a gear ratio is made slower than during normal gear change control.