JPS59208253A - Controlling method of stepless speed change gear for vehicle - Google Patents

Abstract

PURPOSE:To make acceleration favorable, by fixing a speed change ratio at a value to be obtained prior to acceleration for a predetermined period of time at the initial stage of the acceleration when a vehicle is accelerated from either a low speed or low load state of an engine. CONSTITUTION:In case of accerelation of a vehicle when an engine is under either a low speed or low load state, a speed ratio (e) of CVT4 is fixed at a value available before acceleration for a predetermined period of time at the initial stage of the acceleration of the vehicle. With this constitution, within the predetermined period of time as a value of Nins.(es-e) on the right side of an expression DELTANout=DELTANin.es-Nins.(es-e) (provided that es as the speed ratio (e) at the starting time of the acceleration of the vehicle, Nins as input side revolving speed Nin at the starting time of the acceleration of the vehicle) is controlled and DELTANout is increased, the Nout, that is, a vehicle speed is increased rapidly. Favorable acceleration, therefore, can be obtained at the initial stage of the acceleration of the vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for a stepless speedboat for both LI and LI, which can continuously control the speed ratio as a power transmission device, and particularly relates to a control method during acceleration.

Engine revolution 1 (ii speed change during acceleration, therefore input side rotational speed N1n of continuously variable transmission (CV'l')
The change amount ΔNin is expressed by the following equation.

ΔNin T-B-yu°yu°-(1) re where T: Engine shaft torque η: CVT transmission efficiency e: CVT speed ratio Nout / N1n (Nou
t and Nin are the output side rotational speed and input side rotational speed of the CVT, respectively) le: Penetrating moment on the engine side On the other hand, the change Δ in the output side rotational speed N Out of the CVT
Nout is expressed by the following equation.

ΔNout −ΔNin −es−Nins−(es
-e) 1 (2) eS: Speed ratio at the start of vehicle acceleration eNfns: Input side rotational speed N at the start of vehicle acceleration
in, that is, ΔN1n-cs is the change in Nout due to ΔNin, and -NIns-(ese) is the change in Nout due to the change in the sg ratio e. Increase the drive torque to accelerate the vehicle! Since it makes C more difficult to recognize, cs
-e becomes a positive value. Therefore, when accelerating the tunryo\N from a state where the IAI is at a low point or at g and fZ1, Nin5・(es-e) increases relatively in equation (2), and the acceleration performance at the initial stage of acceleration increases. The problem is that it gets worse.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control method for a continuously variable transmission for a vehicle that can improve the acceleration performance at the initial stage of acceleration when accelerating a Φ vehicle from a state where the engine is at low speed or low load.

This purpose? -According to the present invention, when accelerating 11c from a state where the engine is at low speed or with a low load, the speed ratio C of the CVT is changed before acceleration within the initial predetermined time of , or change the CVT speed change speed e (time differential of the speed ratio C) gradually.

As a result, within this predetermined time, (2) Nj+1 on the second right side
The value of s・(es−e) is suppressed, which makes ΔN o
Since ut increases, Nout (~vehicle speed) increases quickly, and good acceleration performance can be obtained at the initial stage of heavy vehicle acceleration. In addition, in order to make the car maintain the shifting speed at 0 within this predetermined 1 pH, →Y, 5', and...-L L-,' L, by confusingly transforming Δ 'Increase Jout to a larger value,
Acceleration performance can be further improved.

The present invention will be described in detail with reference to the drawings.

In FIG. 1, a crankshaft 2 of an engine 1 is connected to an input shaft 5 of an engine 4 via a clutch 3. A pair of input side disks 6a and 6b are provided facing each other, and one of the input side disks 6a is axially relative to the input shaft 5.
The input side disk 6b for external force is provided on the input shaft 5.
is fixed. Also, a pair of output side disks 7a.

7b are also provided facing each other, one output side disk 7a is fixed to the output shaft 8, and the other output side disk 7b
is provided on the output shaft 8 so as to be movable in the axial force direction.

The belt 9 has a uniform cross section and is stretched between the input disks 6a, 6b and the output disks 7a+7b.

The opposing surfaces of the input side disks 6a, 6b and the opposing surfaces of the output side disks 7a+7b are formed into tapered ujt surfaces such that the distance between them increases as they proceed radially outward. Input side and output side disks 6a in relation to increases and decreases in the order of distance between opposing surfaces.

6b,? a, the radius of engagement of the belt 9 at 71+ increases or decreases, and the speed ratio and transmission torque change.

The mail pump 14 sends oil sucked from the oil sump 15 to the pressure regulating valve 16. The linear solenoid type pressure regulating valve 16 controls the discharge of oil to the drain 17, thereby controlling the line pressure of the line 18. The oil passage 18 is connected to the hydraulic cylinder of the output (Ill disk 7b).The linear solenoid type flow control valve I9 is connected to the input side disk 6a +
Increasing the pressing force Nc) between the input side disks 6a and /! The flow f between the oil passage 20 and the oil passage 18 to the 11-pressure cylinder (increasing the 47 area and the oil passage 2Q and the drain 17) is interrupted, and the pressing force between the input side disk Oa + 61 + is At the 4th turn, the connection between the oil passage 8 and 20 is cut off, and the flow cross-sectional area between the oil passage 20 and the drain 17 is created. The sensors 23 and 24 detect the rotational speeds Nin + Nout of the input side disk 6b and the output side disk 7a, respectively.The cylinder oil pressure of the output side denosk 7b, that is, the line pressure, can be transmitted from 1 to 1 lux without the belt 9 force. The hydraulic pressure is controlled to the maximum that can be secured, thereby suppressing the driving loss of the pump 14.

The oil flow to the input side disc 6a [by CVT'
A speed ratio of 4 is controlled. Note that the cylinder oil pressure of the output side disk 7b≧the cylinder oil pressure of the input side disk 6a, but the pressure receiving area of the cylinder piston is input side>output side, and a speed ratio of 1 or more can be realized. Water width sensor 25
detects the cooling water level of engine 1.

The throttle opening sensor 26 detects the opening of an intake system throttle valve that is linked to the accelerator pedal 27.

Shift position [rl sensor 28 detects the range of the shift lever near the seat 29.

FIG. 2 is a block diagram of the electronic control device Pe.

CPU 32, RAM 33, RO +34, r/
F (interface) 35, A/D (analog/digital converter) 36, and D/Δ (digital/
The analog converters) 37 are connected to each other by a bus 38. The output pulses of the rotation angle sensors 23, 24 and the shift position sensor 28 are sent to the interface 35,
The analog outputs of the water temperature sensor 25 and the throttle opening sensor 26 are sent to the A/D 36, and the output of the D/A 37 is sent to the pressure regulating valve 16 and the flow rate control valve 19.

To roughly explain the control layer IIj of the CVT II, the required horsepower for the internal combustion engine 1 is determined as a function of the intake system throttle opening degree 0, and the engine rotation speed Ne at which the required horsepower occurs at the minimum fuel efficiency is defined as the target engine rotation speed Neo. shall be. Therefore, the target engine rotational speed Neo is a function of the opening degree of 1 to 0. Also, the speed ratio e of the CVT 4 when the engine rotation speed Ne becomes the target engine rotation speed Neo is the target speed ratio e.
o.

That is, C0==Nout/Neo. In this way, the pressure regulating valve 10 and the flow LL control valve 19 are controlled so that the speed ratio e of the CVT 4 becomes the target speed ratio ea.

FIG. 3 shows the absolute value of the shift speed during acceleration at CV'r4 of the example, and the change over one hour.

In other words, during acceleration, the lotus degree ratio e is decreased due to the increase in driving torque, so the time differential value of the speed ratio e is 2 (=
de/dt) is negative. When accelerating a vehicle from a state where the engine is at low load or low speed, the acceleration start time t
= Until time t2 when a predetermined time Ta has elapsed from tl,
Shift speed 2 is held at 0. Therefore, the speed ratio C is maintained at the value es immediately before acceleration until t2 t2. two t2
Thereafter, the shifting speeds are set to the original value -X for achieving the target speed ratio eO as a function of the throttle opening θ.

Figure 4 shows ΔNout and Nin5 (es
-e) in the embodiment of FIG. 3 according to the present invention (
The solid line) and the conventional device (broken line) are shown in comparison.

ΔNin increases smoothly with the start of acceleration, but in the conventional device, since the speed ratio e changes immediately from the acceleration start time t = tl, Nuns (es-e) increases and ΔNout becomes tJ\\ at the beginning of acceleration. However, there is a problem that the increase in vehicle speed is delayed. On the other hand, in the present invention, t =: Nin5 (cs - e) force 50 until t2
Since ΔN0ut is maintained at a large value from the beginning of acceleration, the vehicle speed quickly increases from t==tl, and good acceleration performance is obtained. In addition, in FIG. 4, in the latter stage of acceleration, the magnitude relationship of ΔlN0ut is reversed between the present invention and the conventional device, but the acceleration performance of the initial acceleration vj meets the driver's requirements and is more important than in the latter stage of acceleration. Also, -Ni
The reason why there is a lower limit for ns (es-e) is that the speed ratio C of the CVT 4 has a lower limit cmin.

FIG. 5 is a flowchart of the speed change process for executing the control shown in FIG. 3. Is it larger than the value of the engine 1 or low load? If the load has changed to rS load failure or the engine l is in a high color load condition in terms of δ, and the input side rotational speed Nin (=Ne) of CVI' 4 is smaller than the predetermined value 13, In other words, if the accelerator pedal is depressed when the engine is at low speed or under low load, or if the engine is at low speed and the Drl speed pedal is continuously depressed greatly, the rapid speed 2 will be depressed for only T seconds. In other cases, a is set to the original value - If θ≦A, the process proceeds to step 54.In step 46, the CVT
Compare the input side rotational speed Nin of No. 4 with the predetermined value B, and
If n<8, proceed to step 48 1liiyl 2
If it is B, proceed to the step knob 54. In step 48, a timer is activated. In step 50, the elapsed time T measured by the timer is compared with Ta, and T<T
If a, proceed to step 52, and if T≧1”a, GJ
Proceed to step 54. In step 52, only the gear shift speed is set to O.
Make it. In step 54, 0 is substituted for 1'. In step 56, the shift speed \2 is set to the original value -X for achieving the target speed ratio eo as a function of the throttle opening degree O.

FIG. 6 shows the time change of the absolute value +5+· of the shift speed 6 during L acceleration in another embodiment of the present invention. When the engine is accelerating on the middle side from a low load or low speed state, the absolute value of the shift speed (51) is unambiguously changed from acceleration start time t-th to time t2 when a predetermined time Ta has passed. raise. As a result, Nin5 (es
-c) can be suppressed from increasing, and Nout can be raised appropriately to its maximum value.

FIG. 7 is a flowchart h of a shift speed calculation routine for executing the control shown in FIG. The difference from the embodiment in FIG. 5 is that step 52 (instead of the 54th step 52)
), and in step 521), f
Substitute (t). f (t) is t-tl~ in Fig. 6
151, which is defined in the range up to t2, has the opposite relationship, i.e., f (t)=-+e+
It is expressed as

4 I'+ji B'+ Explanation of the Drawings Fig. 1 is an overall schematic diagram of a cVT to which the present invention is applied, Fig. 2 is a block diagram of an electronic control device, and Fig. '3 is an illustration of an embodiment of the present invention. Figure 4 shows the change in shift speed of C V 'I' over time during acceleration. Figure 4 shows CV during acceleration]
Figure 5 is a diagram showing changes over time in the output side rotational speed, etc.
A flowchart of a gauze speed calculation routine that executes the control shown in the figure, FIG. 6 is a diagram showing the time change of the CVT shift speed during acceleration in another embodiment of the present invention, and FIG. 7 is a flowchart of the control shown in FIG. 6. 2 is a flowchart of a shift speed calculation routine that executes.

1... Engine, 4... CVT, 19... Flow control valve.

Patent applicant: Toyota Motor Corporation Figure 3 tl t2 time Figure 4 Figure 5 Figure 6 tl t2 t2 time shown in Figure 7

Claims (1)

[Claims] 1. When accelerating a vehicle from a state in which the engine is at (1, ti speed or low 11-3 load), at a predetermined time at the beginning of vehicle acceleration, the speed ratio of the continuously variable transmission is set to the value before acceleration. 2. When accelerating a vehicle from a state where the engine is at low speed or low load, the control force method for a continuously variable transmission for a vehicle is fixed at
1 (Method for producing a continuously variable transmission for a vehicle, which is characterized by gradually changing the speed of the gear transmission).