JP2668902B2 - Control method for continuously variable transmission for vehicle - Google Patents

Description

TECHNICAL FIELD The present invention relates to a technique for controlling a gear ratio of a continuously variable transmission mounted on a vehicle. [Prior Art] Conventionally, there is disclosed a technology of detecting a driver's dozing state from an electroencephalogram (α wave), a pulse, or the like, or detecting from a frequency of meandering driving of a vehicle and issuing an alarm such as "rest". (See Japanese Utility Model Laid-Open No. 56-73638). Further, in the shift control of the continuously variable transmission mounted on the vehicle, for example, the depression speed of the accelerator pedal is detected as the operation state of the driver, and the speed of change of the gear ratio is changed according to the degree of the depression speed. I am trying to improve the feeling of acceleration. [Problems to be Solved by the Invention] However, like the prior art, the doze state is detected based on the physiological action of the driver or the running state of the vehicle, and "pictogram of coffee cup" or the like is displayed, or It is not possible to prevent the driver's fatigue from being accumulated and to prevent the driver from feeling an unexpected acceleration when the driver is tired only by giving an alarm to the driver in a dozing state by producing a sound. This is because the conventional technique does not consider the change in driving feeling due to the fatigue of the driver as shown below. That is, for example, when fatigue is accumulated during long-time running, even if the gear ratio of the continuously variable transmission changes as in the normal state due to the driver depressing the accelerator pedal, the driver will not request In order to control the change in the behavior of this vehicle by feeling that the vehicle has accelerated
It sometimes contributed to fatigue. 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 means for achieving the above object, a control method for a continuously variable transmission for a vehicle according to the present invention, as exemplified in FIG.
In a method for controlling a speed ratio of a continuously variable transmission mounted on a vehicle based at least on an operation state of a driver of the vehicle, the shift control based on the operation state of the driver (step SB, SC) includes the step of: When a fatigue state of the user is detected (step SA), the speed of change of the gear ratio is made slower (step SB) than in the normal gear shift control. A continuously variable transmission mounted on a vehicle is a transmission that uses a belt or a bearing or the like to continuously control the gear ratio according to a command from a computer or the like. The driver's fatigue state is detected based on, for example, a meandering driving state, a vehicle operating state obtained from the accelerator pedal depression frequency and the magnitude of the depression speed, and the state of physiological phenomena such as electroencephalogram and pulse. The shift control during normal operation is, for example, to control the gear ratio of the transmission based on at least the accelerator pedal depression amount, for example, so as to maintain good fuel economy during steady running and to improve acceleration during acceleration. is there. To reduce the speed of change of the gear ratio means, for example, switching a valve that controls the speed of change of the gear ratio of a hydraulic continuously variable transmission, such as a flow control valve or a hydraulic control valve, to a valve that reduces the speed of changing the gear ratio. Alternatively, for example, the gear shift pattern for obtaining the target gear ratio from the accelerator depression amount may be changed to one in which the gear ratio changes a little less than the normal time even if the accelerator depression amount changes. [Operation] When the vehicle driver's fatigue state is not detected, the control method for the vehicle continuously variable transmission according to the present invention (step S
A): Shift control is performed based on at least the operating state of the driver during normal operation (step SC), while when a fatigue state is detected (step SA), the operating state is changed to a slower speed change ratio than normal. Perform the original shift control (step SB). As a method of slowing down the speed change rate of the gear ratio, for example, the method may be performed by controlling the engagement amount (or clutch speed ratio) of the clutch connected to the continuously variable transmission (by increasing the slip of the clutch). Alternatively, it may be performed by controlling the engine output (decreasing the output). Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 2, a vehicle engine 10 includes a direct-coupled clutch.
It is connected to an input shaft 16 of a continuously variable transmission 14 via a fluid coupling 12 with 11. The input shaft 16 is provided with a variable pulley 22 whose hydraulic groove 18 changes the width of the V groove, that is, the diameter of the transmission belt 20. 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 transmitted to the output shaft 24 via the conductive belt 20 wound around the variable pulleys 22 and 28,
The power is transmitted to the sub-transmission 30 at the subsequent stage. The auxiliary transmission 30 includes a Ravigneaux-type compound planetary gear device including a first sun gear 32, a second sun gear 34, a ring gear 36, and the like.
38, the low speed brake 40 and the reverse brake 42 are selectively operated by a hydraulic actuator (not shown), and as shown in the following Table 1, the transmission ratio Rf of the subtransmission 30 is changed.
Are switched, or normal rotation and reverse rotation are switched. Here, in Table 1, ρ1 is Zs1 / Zr, and ρ2 is Zs2 / Zr. Here, Zs1 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. The output shaft 24 of the belt-type continuously variable transmission 14 constitutes the input shaft of the auxiliary transmission 30 and a carrier that supports the planetary gears in the auxiliary transmission 30.
Since 44 constitutes an output shaft, the gear ratio of the auxiliary transmission 30 becomes a value obtained by dividing the rotation speed of the output shaft 24 by the rotation speed of the carrier 44. The rotational force transmitted to the carrier 44 is transmitted to a pair of drive wheels 52 of the vehicle via the intermediate gears 46 and 48 and the final reducer 50. Near the variable pulleys 22 and 28, these variable pulleys
Pulse signal SP1 of frequency corresponding to rotation speed of 22 and 28
And an output shaft rotation speed sensor 60 for outputting SP2 and SP2 to the controller 54. In the vicinity of the intermediate gear 48, a vehicle speed sensor 61 for outputting a pulse signal SV having a frequency corresponding to the rotation speed of the intermediate gear 48 to the controller 54 is provided. A throttle valve 62 provided in an 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 sensor 64 detects a throttle valve opening θ from the throttle sensor 64. Express throttle signal S
θ is supplied to the controller 54. The ignition circuit of the engine 10 is provided with an engine speed sensor 65, from which a speed signal SNE representing the engine speed Ne is supplied to the controller 54. In this embodiment, a shift lever 66 is used as a shift switching device. From an operation position sensor 68 that detects the operation position of the shift lever 66, a signal SP indicating the shift operation position Psh of the shift lever 66 is sent to the controller 54. Supplied to This shift lever 66 is mechanically associated with a manual valve in the hydraulic circuit 70, and when operated in the neutral range, the high speed clutch 38,
This prevents the hydraulic pressure from being supplied to any of the hydraulic actuators for operating the low-speed gear brake 40 and the reverse brake 42, respectively.However, when operated in the reverse range, the hydraulic actuator that operates the reverse brake 42 is operated. Only supply hydraulic oil. Also, shift lever 66
Is operated in the normal traveling (D: drive) range of the forward range, the hydraulic oil is supplied only to the hydraulic actuator that operates the high speed clutch 38, and the high speed gear To be maintained. When the shift lever 66 is set to the automatic shift range (S
Range) or the engine brake range (L range), the hydraulic oil is allowed to be supplied to either of the hydraulic actuators for operating the high speed clutch 38 and the low speed brake 40. To do. To these hydraulic actuators, hydraulic pressure is alternatively supplied 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 the hydraulic cylinder 26 provided on the output shaft 24 with a line hydraulic pressure adjusted in accordance with the actual speed ratio of the continuously variable transmission 14 and the output torque of the engine 10,
The tension of the conduction belt 20 is necessary and sufficiently controlled. Also,
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 includes a shift speed switching valve.
In response to the operation of 76, the hydraulic oil inflow speed to the hydraulic cylinder 18 or the hydraulic oil discharge speed from the oil cylinder 18 is changed, and in response to the operation of the lock-up switching valve 77, the hydraulic oil to the direct coupling clutch 11 is changed. Switch direction. The operations of the shift direction switching valve 74, the shift speed switching valve 76, and the lockup switching valve 77 are controlled by the controller 54, and the shift direction switching valve 74 controls the transmission of the continuously variable transmission 14 to increase or decrease. The shift speed switching valve 76 controls the speed of change of the gear ratio, and the lockup switching valve 77 controls the amount of engagement (transfer torque) of the direct coupling clutch 11. The hydraulic pump 78 is driven by the engine 10 or the like to move the hydraulic oil in the oil tank 80 into a hydraulic circuit.
The hydraulic pressure is supplied to the hydraulic circuit 70 and functions as a hydraulic pressure source of the hydraulic circuit 70. A steering column sensor 81 such as a photo interrupter is provided on a steering column (not shown) of the vehicle, and a steering angle signal SD indicating the steering angle θd is supplied to the controller 54. The controller 54 includes an input / output interface 82, a central processing unit 84, a storage unit 86, etc., and various input signals input via the input / output interface 82 according to programs and data stored in the storage unit 86 in advance. By controlling the operation of the shift solenoid valve 72 based on the processing result, thereby automatically shifting the gear stage of the subtransmission 30 to the shift direction switching valve 74 and the shift speed switching valve 76.
The operation of the continuously variable transmission 14 is changed to an optimum value, and the operation of the lock-up switching valve 77 is controlled to lock the direct-coupled clutch 11 on or off. To Next, a gear ratio control routine according to the present embodiment, which is executed every predetermined time (here, 8 msec), will be described with reference to the flowchart of FIG. FIG. 3 shows a control routine for controlling the speed ratio of the entire transmission of the vehicle. First, the vehicle speed V, the throttle opening θ, the rotation speed Nin of the input shaft 16 and the rotation speed Nout of the output shaft 24 are shown. , Engine speed Ne, shift lever
66 operation position Psh and steering angle θd are signal SV, Sθ, SP1, SP2, SN
Reading is performed based on E, SP, and SD (step 100). Then
It is determined whether the actual operation position of the shift lever 66 is in the normal travel range or the automatic shift range (step 11).
0). If it is determined that the transmission is in the normal traveling range, the speed ratio control routine in the normal traveling 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), the sub-transmission 3
The shift control of 0 is executed (step 130). That is,
From the shift pattern stored in the storage unit 86 in advance, the vehicle speed V
The gear stage of the auxiliary transmission 30 is determined based on the throttle opening θ, and a drive signal is output to the shift electromagnetic valve 72 so that the determined gear stage is realized. The shift pattern is, for example, as shown in FIG. 5, and is stored in a form such as a data map. In the figure, U12 is prepared in consideration of the running performance of the vehicle, and is used to determine an upshift from a lower gear (first speed) to a higher gear (second speed). It is a shift line, and D21 in the figure is
It is prepared to form an appropriate hysteresis and considering the acceleration performance by kick down,
It is a downshift line used to determine a downshift from a higher gear to a lower gear. Next, it is determined whether the actual gear of the subtransmission 30 is the high gear or the low gear (step 140). If it is determined that the gear is the higher gear,
For example, instead of the gear ratio control routine (step 120) in the normal running range shown in FIG. 4, a gear ratio control routine in a high gear stage (not shown in detail) is started to execute the gear ratio control of the continuously variable transmission 14. (Step 150). If it is determined in step 140 that the gear stage of the auxiliary transmission 30 is the lower gear stage, for example, instead of the speed ratio control routine (step 120) in the normal traveling range shown in detail in FIG. 4, A gear ratio control routine in a low gear stage (not shown in detail) is started, and the continuously variable transmission is started.
The gear ratio control of 14 is executed (step 160). Next, the gear ratio control routine in the normal traveling range of FIG. 4 will be described. In the control routine of FIG. 4, first, a meandering operation is determined based on the fatigue state of the driver based on the change state of the steering angle θd (step 210). The judgment of the meandering operation is to judge that the steering wheel is the meandering operation when a state in which the steering wheel is cut into a small angle with respect to straight ahead continues for a predetermined time or more and is repeated a predetermined number of times or more. If it is determined that the vehicle is not currently in the meandering operation state based on the determination of the meandering operation, the storage unit 86 stores
The storage section 8 stores the target speed Nin ^* data map for the normal normal traveling range stored in the ROM shown by the solid line in FIG.
Set to the work area in RAM 6 (step 22)
0). On the other hand, when it is determined that the vehicle is currently in the meandering operation state, as shown in FIG.
R in normal storage unit 86 the target speed Nin ^* data map of fatigue during a normal driving range to provide a lower target rotation speed Nin ^* of the same throttle opening θi compared to such as shown by dash-dotted
Set it in the work area in AM (step 230). After setting the target rotation speed data map in the work area, the target rotation speed Nin ^* is calculated next with reference to the target rotation speed Nin ^* data map stored in the work area, and the process proceeds to step 100 in FIG. Read vehicle speed Vi. (I =
0 to max) and the throttle opening θ (step 240). After calculating the target rotation speed Nin ^* , control for actually changing the gear ratio of the continuously variable transmission 14 is performed (steps 250 to 270). That is, first, it is determined whether the target rotation speed Nin ^* is less than or equal to the rotation speed Nin of the input shaft 16 (step 250). Next, if Nin ^* > Nin, it is determined that the rotational speed Nin of the input shaft 16 is to be increased, and the shift direction switching valve 14 and the shift speed switching valve 76 are controlled to change the speed of the continuously variable transmission 74. Control for increasing the ratio γ (downshift control) is executed (step 260). On the other hand, when the target rotation speed Nin ^* is smaller than the rotation speed Nin of the input shaft 16, control for reducing the speed ratio γ of the continuously variable transmission 14 (upshift control) is executed (step 270). By performing steps 210 through 270 above, the shift lever 16
When the vehicle is not meandering, the gear ratio of the continuously variable transmission 14 in the normal driving range is based on the target speed Nin ^* data map for the normal normal driving range shown by the solid line in FIG. Determined and actually controlled. on the other hand,
In the case of the meandering operation, it is determined based on the Nin ^* data map indicated by the two-dot chain line in FIG. 6 and is actually controlled. Therefore, during the meandering operation due to the fatigue of the driver, the actual gear ratio of the continuously variable transmission 14 is normally calculated from the current vehicle speed V and the throttle opening θ as shown by the two-dot chain line in FIG. Target speed Nin ^* lower than time (for example, 20-50% lower Nin ^* when throttle opening θ is 100%)
Based on the above, the speed is increased. In addition, in the gear ratio control in the high speed gear stage (step 150) and the gear ratio control in the low speed gear stage (step 160) in FIG.
Similarly, the meandering operation is determined, and when fatigue occurs, the actual gear ratio is controlled based on the speed-up gear shift pattern. As described above, according to the present embodiment, when the vehicle is meandering in accordance with the fatigue condition of the driver, the continuously variable transmission 14 has the throttle opening θ as the accelerator pedal depressed state rapidly. , Or even if there is a large change, the gear cannot be rapidly shifted to the reduction ratio side (downshift side),
This prevents sudden acceleration. As a result, when the driver is fatigued, smoother driving performance and driving feeling can be obtained as compared with normal time, so that the driver does not feel any unexpected behavior change and the driver's fatigue is reduced. Play. Next, a second embodiment will be described. In this embodiment, as in steps 210 to 230 of the routine shown in FIG. 4 of the first embodiment, at the time of fatigue, instead of setting the target engine speed Nin ^* map for fatigue, the steps 260 and 270 are executed. The downshift speed or the upshift speed in the shift process or the upshift process is directly controlled. When the downshift processing routine shown in FIG. 7 is started, it is determined whether or not the meandering operation is performed as in the first embodiment (step 300). The normal change speed map (not shown) is set in the work area (step 310). This map shows the characteristics over time as shown by the solid line in FIG.
However, the shift speed switching valve 76 is opened so that the rotational speed Nin of the input shaft 16 shifts from Nin1 to Nin2 when the throttle opening θ1 changes to θ2 at time t0. On the other hand, if the vehicle is in the meandering operation state, it is similarly shown in FIG.
As shown by the dotted line, a change rate map at the time of fatigue is set in the work area so that the change rate of the gear ratio γ is slower than that in the normal time (for example, 50 to 100% slower) and the time-dependent characteristics are met (step 320). After setting the above map, next shift direction switching valve
74 is switched to the downshift side (step 330), and then the open state of the shift speed switching valve 76 is controlled according to the throttle opening θ and the elapsed time t based on the map set in the work area (step). 34
0). It should be noted that during upshifting as well as during downshifting, control is performed based on the meandering state. Therefore, during the meandering operation due to the driver's fatigue, the speed of change of the gear ratio based on the accelerator pedal depression speed becomes slower than usual. As described above, according to the second embodiment, as in the first embodiment, the accumulation of fatigue of the driver at the time of fatigue is reduced, and the safety is improved. For example, the gear ratio of the continuously variable transmission 14 is changed to a computer or the like. It has an extremely excellent effect that it can be applied to a control method without using the electronic control circuit. In addition,
The present invention is not limited to the above embodiment.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 a physiological phenomenon such as an electroencephalogram or a pulse may be used. Further, the present invention may be applied to a stepped transmission as long as the transmission ratio is controlled as in the case of a continuously variable transmission. [Effect of the Invention] When the driver's fatigue state is detected, the control method of the vehicle continuously variable transmission according to the present invention reduces the speed of change of the gear ratio as compared to the normal time, thereby driving in a fatigued state. It is possible to prevent a change in the behavior of the vehicle due to, for example, a sudden sudden acceleration that promotes fatigue of the driver. As a result, due to the effect of reducing the driver's fatigue, the driving safety of the vehicle is improved, and the driving feeling is further improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flowchart illustrating the basic configuration of the present invention, FIG. 2 is a configuration diagram of a system to which one embodiment of the present invention is applied, and FIG. FIG. 4 is a flowchart of a gear ratio control routine in the normal traveling range, FIG. 5 is a graph showing shift characteristics of the sub-transmission of the embodiment, and FIG. 6 is a flowchart of the continuously variable transmission of the embodiment. FIG. 7 is a graph showing shift characteristics, FIG. 7 is a flowchart of a downshift processing routine of the second embodiment, and FIG. 8 is a graph showing 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)

(57) [Claims] In a method of controlling a gear ratio of a continuously variable transmission mounted on a vehicle based on at least an operating state of a driver of the vehicle, the shift control based on the operating state of the driver detects a fatigue state of the driver. When this is done, the method of controlling the continuously variable transmission for a vehicle is characterized in that the speed of change of the gear ratio is made slower than that during normal speed change control.