JPH0681931A - Shift control device for continuously variable transmission - Google Patents

Abstract

PURPOSE:To improve the acceleration responsiveness in control of a speed for a continuously variable transmission. CONSTITUTION:A shift control device for a continuously variable transmission is designed to regulate a change gear ratio 'in' between a primary pullet 26 and a secondary pulley 28. Especially, the shift control device is operated to control the change gear ratio 'in' in such a way that the objective number Npo of revolutions of a primary pulley responding to a throttle opening is provided, weight grade resistance Rw is provided based on operation information of a vehicle, an objective number of revolutions of primary pulley correction amount CNp is corrected from a throttle opening Th and the weight grade resistance, the correction objective number Npc of revolutions of a primary pulley is corrected by a correction amount CNp and the target number of revolutions of a primary pulley, and the actual number of revolutions of a primary pulley is adjusted to the correction objective number Npc of revolutions of a primary pulley.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for a continuously variable transmission that changes a winding diameter ratio of a belt wound around a pair of pulleys by a hydraulic actuator to perform continuously variable transmission.

[0002]

2. Description of the Related Art Conventionally, a belt drive type continuously variable transmission in which a drive belt is wound between a primary pulley and a secondary pulley, and the winding diameter ratio of the belt wound around both pulleys is changed to perform continuously variable transmission. The machine is known. When such a continuously variable transmission is subjected to gear shift control, for example, a target primary pulley rotation speed Npo corresponding to the throttle opening is set or a target torque set separately is set according to a map of characteristics as shown in FIG. Set the target primary pulley rotation speed accordingly. Then, the control means of the continuously variable transmission adjusts the actual primary pulley rotation speed to the target primary pulley rotation speed.

[0003]

When the target primary pulley rotation speed Npo of such a continuously variable transmission is set according to the throttle opening, the set value here is a standard weight of the vehicle on a flat road. It is often calculated as something to drive. For example, when traveling on an uphill bend, the target primary pulley rotation speed Npo corresponding to the throttle opening is simply calculated, and the acceleration of the vehicle can be appropriately increased even if the gear ratio corresponding to the same value is achieved. Therefore, insufficient acceleration is likely to occur. In addition, the operation of turning off the accelerator for deceleration when entering an uphill corner and turning on the accelerator for acceleration when exiting a corner is repeated. Therefore, when entering a corner, the vehicle is climbing up and the accelerator opening is small, and even if the accelerator is fully turned on when exiting the corner, output recovery is delayed and the driving feeling such as acceleration responsiveness deteriorates. There is. An object of the present invention is to provide a shift control device for a continuously variable transmission with improved acceleration response.

[0004]

In order to achieve the above object, the present invention is provided between an input side primary pulley connected to an engine and an output side secondary pulley connected to a drive shaft. A target primary pulley for detecting a target primary pulley rotation speed according to a throttle opening of the engine and a vehicle speed in a shift control device for a continuously variable transmission for a vehicle, which changes a gear ratio by changing a winding diameter ratio of an endless belt. Rotation speed detection means, weight gradient resistance detection means for detecting weight gradient resistance from the driving information of the vehicle, and target primary pulley rotation speed for setting a target primary pulley rotation speed correction amount from the throttle opening and weight gradient resistance. From the correction amount setting means, the target primary pulley rotation speed, and the target primary pulley rotation speed correction amount, the correction target primary pulley speed is set. It has a correction target primary pulley rotation speed setting means for setting the rotation speed and a gear ratio control means for controlling the gear ratio so that the actual primary pulley rotation speed becomes the correction target primary pulley rotation speed. .

[0005]

The target primary pulley rotation speed correction amount is calculated from the weight gradient resistance and the throttle opening based on the vehicle driving information, and the target primary pulley rotation speed correction amount and the target primary pulley rotation speed are corrected. Since the gear ratio is calculated so as to eliminate the deviation between the corrected target primary pulley rotation speed and the actual primary pulley rotation speed, it is possible to appropriately compensate for insufficient acceleration when the vehicle weight increases and when the vehicle is climbing uphill.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The shift control device for a continuously variable transmission shown in FIG. 1 is a continuously variable transmission (C) on a power transmission system P connected to an engine 7 of a vehicle.
VT) 20. Various devices such as an injector 1 for injecting fuel into the engine 7 and a spark plug 2 for igniting the air-fuel mixture are placed under the control of the DBWECU 3 as the electronic control means of the engine.
A CVTECU 21, which is an electronic control unit of the continuously variable transmission 20, is connected to the BWECU 3. Both ECUs
A communication line is connected between the two terminals so that signals can be exchanged between them at all times. The DBWECU 3 is connected to an actuator 11 for driving the throttle valve 9 as an intake air amount operating means that is driven independently of the operation of the accelerator pedal 10.

The engine 7 has a Karman vortex type air flow sensor 6 for detecting the flow rate of intake air from the air cleaner element 5 in the air cleaner body 4. In addition to the air flow sensor 6, an engine speed sensor 24 that outputs information on the engine speed Ne and a throttle opening sensor 1 that outputs information on the throttle opening Th of the throttle valve 9
2, operation information detection means such as an accelerator sensor 13 that outputs accelerator opening θa information of the accelerator pedal 10 and a water temperature sensor 39 that outputs water temperature WT information are provided, and each of these data is measured and input to the DBWECU 3. The well-known configuration is adopted.

The throttle valve 9 is not the accelerator pedal 10 that the driver steps on, but an actuator (in this embodiment,
It is opened and closed by a step motor) 11. In this embodiment, a so-called DBW (drive-by-wire) system in which the actuator 11 is controlled by the DBWECU 3 is adopted, but a normal accelerator pedal and throttle valve connected by a link or the like may be used. Absent. The crankshaft of the engine 7 has a fluid coupling 8 and a planetary gear type forward / reverse switching device 15
The continuously variable transmission 20 of FIG. 5 is connected via the.

Here, the continuously variable transmission 20 is a primary shaft 2 integrally connected to the output shaft of the forward / reverse switching unit 15.
A secondary pulley 28 having a secondary pulley 28 having a secondary shaft 29 that outputs a rotational force is provided on the speed reducer 30 side, and a steel belt 27 is stretched over the primary pulley 26 and the secondary pulley 28. The secondary shaft 29 is configured to transmit the rotational force to the drive wheels 32, 32 of the drive shaft 31 via a speed reducer 30 and a differential (not shown). Both the pulleys 26 and 28 are divided into two parts, and the movable side pulley members 261 and 281
Is fitted into the stationary pulley members 262 and 282 so as not to rotate relative to each other and to be able to contact and separate at a relative interval. This movable pulley material 26
A primary cylinder 33 and a secondary cylinder 34, which are hydraulic actuators for operating the relative distance between the two pulleys, are formed between the No. 1, 281 and the fixed pulley members 262, 282.

A pair of rotation sensors s1 and s2, which detect both rotational speeds Np and Ns of the primary pulley 26 and the secondary pulley 28, are mounted as means for detecting the actual gear ratio in (= Np / Ns). In this case, the movable pulley material 261 is brought closer to the fixed pulley material 262 of the primary pulley 26 to increase the winding diameter of the primary pulley, and the movable pulley 281 is wound away from the fixed pulley material 282 of the secondary pulley 28. To reduce the actual speed ratio in (primary speed Np
/ Secondary rotation speed Ns) is reduced, that is, a low gear ratio (high gear stage) is set, and the reverse operation is performed to obtain a high gear ratio (low gear stage).
Is configured to achieve. Here, continuously variable transmission 20
A hydraulic circuit OR for controlling the above will be described with reference to FIG.

The oil pump 37 is driven by a fluid coupling 8 connected to the engine 7, and the oil pump 3
The hydraulic pressure discharged from 7 is regulated by a regulator valve 40 to an appropriate pressure, so-called line pressure. The regulator valve 40 is duty-controlled by a first electromagnetic control valve 41 that is driven by the CVT ECU 21 at a duty ratio set according to the operating state of the vehicle. The line pressure regulated by the regulator valve 40 is supplied into the secondary cylinder 34 (see FIG. 5) of the secondary pulley 28 and is also introduced into the gear ratio control valve 35. The gear ratio control valve 35 is duty-controlled by a second electromagnetic control valve 42 that is driven by the CVT ECU 21 at a duty ratio that is set according to the operating state of the vehicle, so that the primary cylinder of the primary pulley 26 has a desired gear ratio. The amount of oil supplied into 33 (see FIG. 5) is controlled.

Further, the line pressure is the modulator valve 43.
The hydraulic pressure regulated by the valve is also applied to the gear ratio control valve 35, the first electromagnetic control valve 41, and the second electromagnetic control valve 4.
It is supplied to 2 etc., and acts as these pilot pressures. In addition to the detection signal from the DBWECU 3, the CVTECU 21 is configured to receive both the rotational speeds Np and Ns of the primary pulley 26 and the secondary pulley 28 and the lateral acceleration Gr from the lateral acceleration sensor 44. CV
The main part of the TECU 7 is configured by a microcomputer, and a built-in memory circuit has a target primary pulley rotation speed detection map of FIG. 6, a target primary pulley rotation speed correction amount setting map of FIG. 7, and an engine output control of FIG. The processing routine, the CVT control processing routine of FIG. 9, the target primary pulley rotation speed correction amount setting routine of FIG. 10, and other control programs are stored. FIG. 3 shows a block diagram of the present invention.

Here, the weight gradient resistance detecting means A1 calculates the weight gradient resistance Rw based on the driving information of the vehicle. The target primary pulley rotation speed detection means A2 calculates a target primary pulley rotation speed Npo according to the throttle opening Th of the engine and the vehicle speed V. The target primary pulley rotation speed correction amount setting means A3 sets a target primary pulley rotation speed correction amount CNp according to the weight gradient resistance Rw and the throttle opening Th. The correction target primary pulley rotation speed setting means A4 is a target primary pulley rotation speed correction amount CNp.
And the target primary pulley rotation speed Npo, the corrected target primary pulley rotation speed Npc is set. The deviation rotation speed calculation means A5 is a correction target primary pulley rotation speed Np.
Deviation rotational speed E between c and the actual rotational speed Np of the primary pulley
Calculate 1. The duty ratio setting means A6 sets the duty ratio according to the deviation E1, and the shift control means A7 has the same duty ratio and is the second electromagnetic control valve 42 which is a pulley operating means.
To drive. The second electromagnetic control valve 42 duty-controls the gear ratio control valve 35 to control the hydraulic actuator 33. Here, the deviation rotation speed calculation means A5, the duty ratio setting means A6, and the shift control means A7 constitute a gear ratio control means.

Hereinafter, the shift control device for the continuously variable transmission according to the present embodiment will be described with reference to the engine output control processing routine of FIG.
The control program of the VT control process routine, the target primary pulley rotation speed correction amount setting routine of FIG. 10, and the functional block diagram of FIG. 2 will be described. In this embodiment, the engine 7 is started by operating an ignition key (not shown), and DBWEC shown in FIGS.
Control within U3 and CVTECU 21 is also started. When the control starts, the DBWECU 3 executes a well-known main routine (not shown). Here, the initial setting and the detection data of each sensor are fetched, and the detection data is fetched in a predetermined area determined for each data. Then, well-known controls such as well-known fuel supply control processing and ignition timing control processing are executed, and engine output control processing is executed.

As shown in FIG. 8, in the engine output control processing, sensor detection data, here, throttle opening Th,
Information such as the accelerator opening degree θa, the engine speed Ne, the water temperature WT, etc. is taken into a predetermined area. At step r2, an intake air amount calculation map and a required torque calculation map (not shown) are used to first determine the accelerator opening θa and the engine speed Ne.
The intake air amount A / N is calculated from this, and the required torque To is calculated from this and the engine speed Ne. Step r3
At r4, the water temperature information WT is taken in, the friction loss torque T _WT of the sliding portion is calculated from a predetermined map (see mp1 in FIG. 2), and the friction loss torque T _WT is added to the required torque To to determine the target torque T1. Then, the process proceeds to step r5. Here, the intake air amount A / N corresponding to the target torque T1 and the engine speed Ne is obtained from an intake air amount calculation map (not shown), and the throttle opening Th is calculated from the intake air amount A / N and the engine speed Ne. It is calculated by the opening degree calculation map.

At step r6, the difference between the throttle opening Th and the actual opening θn is calculated to obtain the deviation Δθ, and the deviation Δθ is calculated.
The output Pun that can eliminate θ is calculated, and the output Pun is output to the pulse motor 11 to drive the throttle valve 9,
A target torque T1 is generated in the engine. On the other hand, CVTEC
U21 performs the CVT control of FIG. Here, the initial settings are made, and both rotation speeds Np and Ns of the primary pulley 26 and the secondary pulley 28, which are the detection data of each sensor,
The throttle opening Th, the engine speed Ne, the lateral acceleration G _Y and the like from the DBWECU 3 are fetched and stored in a predetermined area.

In step s3, the vehicle speed V is calculated from the primary pulley rotation speed Np and the reduction ratio ε, and the acceleration α (= dV / dt) obtained by differentiating the vehicle speed V is calculated. The primary pulley rotation speed Np and the secondary pulley rotation speed are calculated. Ns
The actual gear ratio in (= Np / Ns) is calculated.
In step s4, the target primary pulley rotation speed Npo corresponding to the throttle opening Th is calculated by the primary pulley rotation speed calculation map mp2 (see FIGS. 2 and 6). After this, the processing for setting the target primary pulley rotation speed correction amount CNp in step s5 is started.

Here, as shown in FIG. 10, step q
At 1, the weight gradient resistance Rw is calculated. The weight gradient resistance Rw here is, as shown in the equation (6) described later, an aerodynamic resistance R1, an acceleration resistance R2, a rolling resistance R3, a cornering resistance R4, and a resistance R due to a gear shift from the engine driving force Te.
It is set as a value obtained by subtracting 5 and. The engine driving force (driving torque) Te here is a product of the output torque and the gear ratio (the total gear ratio of the forward / reverse switching portion, the continuously variable transmission and the speed reducer), and the output torque is the torque of the fluid coupling 8. It is obtained by multiplying the ratio by the actual engine torque (a value obtained by subtracting pump loss and other loss torque from the engine torque). The aerodynamic resistance R1 here is the expression (1), and the acceleration resistance R2
Is calculated by the equation (2), the rolling resistance R3 is calculated by the equation (3), the cornering resistance R4 is calculated by the equation (4), and the resistance R5 due to the shift is calculated by the equation (5).

Aerodynamic resistance R1 = 1/2 × ρ × S × C _D × V ² [Kgf] (1) where ρ is an air density of 0.1229 [Kgf · sec]
² / m ⁴ ], S is the entire projected area of the vehicle, and here is 1.9.
3 [m ^2], C _D value here is 0.395, V, upon the vehicle speed, and R1 = 0.049V ² [Kgf]. Acceleration resistance R2 = [M + 1 / R × (I E × i 2 + I M + 2 × I T) ] ×
α [Kgf] (2) where M is vehicle weight [K
gf], R is the wheel radius [m], the moment of inertia of I _E is engine [Kgf · m · sec ^2], I _M is the moment of inertia of the CVT and the drive shaft [Kgf · m · s
ec ² ], I _T is the moment of inertia per drive wheel [Kgf · m · sec ² ], and α is the longitudinal acceleration [m] of the vehicle.
/ Sec ² ], i is Np / Ns, and this equation is obtained from the equation of motion of the vehicle. For example, I _E = 0.01
_{6, I M + 2 × I} T = 0.16, if you set R = 0.28, acceleration resistance R2 = [M + 7.4255 × i ² +2.
0408)] × α [Kgf].

Rolling resistance R3 = Ro [Kgf] (3) Here, Ro (= μr × M) is a rolling resistance during free rolling of about 0.013 × M.

Cornering resistance R4 = C _F ² / C _P = (0.6 M / 2 × Gr) ² / C _P f ×
2+ (0.4M / 2 × Gr) ² / C _P r × 2 [Kgf] ・
(4) where C _F is the cornering force [Kgf] and C _P
Represents the cornering power [Kgf / rad]. Further, the front-rear weight distribution of the vehicle is set to 6: 4, and C _P f = 70 [Kg
f / deg] = 4010 [Kgf / rad], C _P r =
90 [Kgf / deg] = 15160 [Kgf / ra
d] and Gr is a lateral acceleration [g], R4 = 6.
It becomes 0389 × 1/10 ⁵ × M ² × Gr ² [Kgf]. Resistance due to gear shift R5 = di / dt × _IE × Ne × 1 / R [Kgf] ... (5) Each of these values is sequentially calculated based on equations (1) to (5), These are adopted in the equation (6) for calculating the weight gradient resistance Rw. Rw = Te-R1-R2-R3-R4-R5 [Kgf] (6) Here, di / dt represents a shift speed.

After the calculation of the weight gradient resistance Rw as described above, q2 is reached from step q1 in the setting process of the target primary pulley rotation speed correction amount CNp. Here, the target primary pulley rotation speed correction amount CNp corresponding to the throttle opening Th and the weight gradient resistance Rw is set based on the target primary pulley rotation speed correction amount setting map mp3 of FIG. 7, and the process returns. In this target primary pulley rotation speed correction amount setting map, the correction amount CNp is set in a large region of the throttle opening Th having a small drive margin so that the correction amount CNp becomes sufficiently large in the middle region of the throttle opening Th having a large drive margin. The correction amount CNp is set to be large when the weight gradient resistance Rw is large and the throttle opening is in the middle range so that the throttle opening T is set to be small.
Responsiveness is particularly improved in the middle range of h.

When s6 is reached from step s5 of the CVT control processing, the corrected target primary pulley rotation speed Npc is calculated here by adding the target primary pulley rotation speed Npo and the target primary pulley rotation speed correction amount CNp. Further, in step s7, the deviation E1 between the corrected target primary pulley rotation speed Npc and the actual primary pulley rotation speed Npn
(= Npc-Np) is calculated, and subsequently, in step s8, the duty ratio according to the deviation E1 is determined. Then, in step s9, the second electromagnetic control valve 42 is driven at the duty ratio set in step S8, and the process returns to the main routine. That is, the gear ratio control valve 35 receives the control pressure from the second electromagnetic control valve 42 driven at the duty ratio set in step s8, and controls the amount of oil supplied to the primary cylinder 33. Change the gear ratio so that the actual primary pulley rotation speed approaches the target primary pulley rotation speed.

As a result, when the continuously variable transmission 20 shifts, the actual primary pulley rotation speed Np is first adjusted to the correction target primary pulley rotation speed Npc, and the gear ratio is set larger as the weight gradient resistance Rw increases. As a result, the acceleration response is sufficiently improved, especially during climbing.

[0025]

As described above, the shift control device for a continuously variable transmission according to the present invention sets the target primary pulley rotation speed correction amount based on the weight gradient resistance and the throttle opening based on the driving information of the vehicle. Since the correction target primary pulley rotation speed is set from the target primary pulley rotation speed correction amount and the target primary pulley rotation speed, and the actual primary pulley rotation speed is adjusted to reach this correction target primary pulley rotation speed, the weight gradient resistance is large. The higher the gear ratio is set, the acceleration response is sufficiently improved, and particularly the acceleration response during climbing is improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a shift control device for a continuously variable transmission as an embodiment of the present invention.

2 is a functional block diagram of an electronic control unit in the apparatus of FIG. 1. FIG.

FIG. 3 is a configuration block diagram of the present invention.

FIG. 4 is a hydraulic circuit diagram in the apparatus of FIG.

5 is a cross-sectional view of a main part of a continuously variable transmission used by the device of FIG.

FIG. 6 is a characteristic diagram of a target primary pulley rotation speed detection map adopted by the electronic control device in the device of FIG.

7 is a characteristic diagram of a target primary pulley rotation speed correction amount setting map adopted by the electronic control device in the device of FIG.

8 is a flow chart of an engine output control routine adopted by the electronic control unit in the apparatus of FIG.

9 is a CVT adopted by the electronic control unit in the apparatus of FIG.
It is a flowchart of a control processing routine.

10 is a flowchart of a target primary pulley rotation speed correction amount setting routine adopted by the electronic control unit in the apparatus of FIG.

[Explanation of symbols]

 3 DBWECU 7 engine 12 throttle opening sensor 13 accelerator sensor 20 continuously variable transmission 21 CVT ECU 23 electromagnetic control valve 24 engine speed sensor 26 primary pulley 27 drive belt 28 secondary pulley 33 primary cylinder 34 secondary cylinder 35 speed ratio control valve 44 lateral Acceleration sensor in Actual gear ratio s1 Rotation sensor s2 Rotation sensor Pc Gear change control oil pressure Rw Weight gradient resistance CNp Target primary pulley rotation speed correction amount Pp Pulley control oil pressure Pr Pulley control oil pressure

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location F16H 59:66 8009-3J

Claims (1)

[Claims] 1. A gear ratio is changed by changing a winding diameter ratio of an endless belt wound between an input-side primary pulley connected to an engine and an output-side secondary pulley connected to a drive shaft. In a shift control device for a continuously variable transmission for a vehicle, a target primary pulley rotation speed detecting means for detecting a target primary pulley rotation speed according to a throttle opening degree of the engine and a vehicle speed, and a weight gradient resistance from the driving information of the vehicle. Weight gradient resistance detecting means for detecting, target primary pulley rotation speed correction amount setting means for setting a target primary pulley rotation speed correction amount from the throttle opening and weight gradient resistance, the target primary pulley rotation speed and the target primary Set the correction target primary pulley rotation speed based on the pulley rotation speed correction amount. A speed change control device for a continuously variable transmission, comprising: a control means; and a speed change ratio control means for controlling a speed change ratio so that an actual primary pulley speed becomes the corrected target primary pulley speed.