JP2001141048A - Transmission control device of continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control an operation state of an engine brake during running on a descent slope according to a wish of a driver in relation to a transmission control device of a continuously variable transmission. SOLUTION: A desired acceleration setting means 52 sets a desired acceleration in accordance with a road gradient, a change gear ratio control means 56 controls a change gear ratio of the continuously variable transmission so that an actual acceleration of a vehicle is the desired acceleration, an under-or- over determining means 52C determines under-or-over engine brake, and a learning correcting means 52B learns and corrects the desired acceleration based on the determination by the under-or-over determining means 52C.

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 provided in a vehicle such as an automobile.

[0002]

2. Description of the Related Art On a downhill road, there is a case where a vehicle travels by operating only an engine brake without operating an accelerator and a brake. In a vehicle equipped with a continuously variable transmission, the operation state of the engine brake can be controlled by controlling the speed ratio of the continuously variable transmission, and a target acceleration (target deceleration) is set according to a road gradient, A technique has been proposed in which the speed ratio of the continuously variable transmission is controlled so that the actual acceleration (actual acceleration) of the vehicle becomes a set target acceleration.

[0003]

However, there is a driver's preference for the operation state of the engine brake of the vehicle when traveling on a downhill, and there are those who want to get down quickly without applying the engine brake. Some people want to apply the engine brake strongly and get off slowly. Therefore, if the target acceleration when traveling on a downhill road is set uniformly according to the road gradient and the vehicle speed, such driver's preference will be ignored, leading to deterioration of the driving feeling.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a shift control device for a continuously variable transmission, which is capable of controlling the operation state of an engine brake during downhill running according to the driver's preference. The purpose is to provide.

[0005]

SUMMARY OF THE INVENTION To achieve the above object, a shift control device for a continuously variable transmission according to the present invention is provided with a shift control device connected to an engine for controlling the operation state of an engine brake during traveling on a downhill road. In a transmission control device for a continuously variable transmission that variably controls a speed ratio of a stepped transmission, a target acceleration is set according to a road gradient by target acceleration setting means, and an actual acceleration of the vehicle is set to the target acceleration by the speed ratio control means. The speed ratio of the continuously variable transmission is controlled as described above, the excess or deficiency of the engine brake acting on the vehicle is determined, and the target acceleration is learned and corrected by the learning correction means based on the determination of the excess or deficiency determination means.

Preferably, the vehicle further comprises an acceleration / deceleration request operation detecting means for detecting a driver's acceleration / deceleration request operation, and based on the driver's acceleration / deceleration request operation detected by the acceleration / deceleration request operation operation, excessive or insufficient engine brake. Is determined. More preferably, the acceleration / deceleration request operation detecting means is provided with a means for detecting the accelerator operation of the driver, and the excess / shortage determining means is provided with a means for calculating the accelerator operation ratio (for example, accelerator depression time within a predetermined time). When the accelerator operation ratio during traveling on a sloping road is equal to or greater than a predetermined value, it is determined that the engine brake is excessive, and the target acceleration is increased and corrected by the learning correction unit.

More preferably, a means for detecting the driver's brake operation is provided as the acceleration / deceleration request operation detection means, and the brake operation ratio (for example, the time decelerated by the brake operation within a predetermined time) is calculated by the excess / deficiency determination means. When the rate of brake operation during downhill running is equal to or greater than a predetermined value, it is determined that the engine brake is insufficient, and the learning correction means corrects the target acceleration to decrease.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. A gear ratio control device for a continuously variable transmission according to an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a belt-type continuously variable transmission is used as the continuously variable transmission (CVT).

First, the power transmission mechanism according to the present embodiment will be described. As shown in FIG. 2, in this power transmission mechanism, the driving force output from the engine 1 is controlled by a torque converter (torque converter) 2 and a belt type. The power is transmitted to the tire 30 via the step transmission 20 and the differential 31. A forward / reverse switching mechanism 4 is disposed between the output shaft 7 of the torque converter 2 and the input shaft 24 of the belt-type continuously variable transmission 20, and the rotation input from the engine 1 via the torque converter 2 is The input is input to the continuously variable transmission mechanism 20 via the forward / reverse switching mechanism 4.

The continuously variable transmission mechanism 20 is composed of a primary pulley (input pulley) 21, a secondary pulley (output pulley) 22, and a belt 23. The rotation of the secondary shaft 2 is performed via the belt 23 from the primary pulley 21 coaxially integrated with the primary shaft 24.
5 is input to the secondary pulley 22 coaxially integrated with the pulley 5.

The primary pulley 21 and the secondary pulley 22 are respectively two sheaves 21a, 2 which rotate integrally.
1b, 22a and 22b. One of the sheaves 21a, 22a is a fixed sheave fixed in the axial direction, and the other sheave 21b, 22b is a movable sheave movable in the axial direction by hydraulic actuators (eg, hydraulic pistons) 21c, 22c.

The oil pump 62 pressurizes and discharges the oil in the oil tank 61, and the discharge pressure is regulated to a predetermined pressure (predetermined line pressure) by a pressure regulating valve 63. The line pressure PL regulated by the pressure regulating valve 63 is applied to the hydraulic actuator 22c of the secondary pulley 22, and the flow rate is regulated by the flow regulating valve 64 disposed downstream of the pressure regulating valve 63 to the hydraulic piston 21c of the primary pulley 21. Adjusted hydraulic oil is supplied, and this hydraulic oil acts as a gear ratio adjustment hydraulic pressure.

The pressure regulating valve 63 and the flow regulating valve 64 are controlled by a controller (Electronic Control Unit = ECU) 50 by an engine speed sensor 41,
An airflow sensor 42, a primary rotation speed sensor 43 for detecting the rotation speed of the primary pulley 21, a secondary rotation speed sensor 44 for detecting the rotation speed of the secondary pulley 22, and a line pressure sensor 4 for detecting the line pressure PL.
5 is controlled based on each detection signal.

In this embodiment, the speed ratio of the continuously variable transmission is controlled so that an engine brake according to the driver's preference can be obtained when traveling downhill. For this reason, the ECU 50 is provided with a shift control device 60 as shown in the functional block diagram of FIG. 1, and the actual longitudinal acceleration (actual longitudinal G) of the vehicle is reduced by the shift control device 60 when traveling on a downhill road. The gear ratio control of the continuously variable transmission 20 is performed by setting the target primary rotational speed so that the actual primary rotational speed (actual primary rotational speed) matches the target primary rotational speed. It has become.

As shown in FIG. 1, the speed change control device 60 includes a descending slope determining means 51, a target acceleration setting means 52, a target driving force setting means 53, a target output setting means 54, a target primary rotational speed setting means 55, And a primary pulley control means (gear ratio control means) 56 for controlling the primary pulley 21 (oil pressure to the hydraulic actuator 21c) based on the target primary rotation speed set by the target primary rotation speed setting means 55. You.

The downhill determination means 51 determines whether or not the vehicle is traveling on a downhill on the basis of the road gradient information. Is output to the target acceleration setting means 52 in order to perform the speed ratio control according to. The target acceleration setting unit 52 includes a target acceleration setting unit 52A, a learning correction unit (learning correction unit) 52B, and an excess / deficiency determination unit (excess / deficiency determination unit) 52C. The target acceleration setting unit 52A sets the target acceleration GXT based on the vehicle speed V and the road gradient SL (= weight / gradient resistance RS / vehicle weight) [GXT (V, SL)], and sets the set target GXT. A signal corresponding to the acceleration GXT is output to a target driving force setting unit 53 described later. The weight / gradient resistance RS is a value obtained by subtracting acceleration resistance, air resistance, rolling resistance, and the like from the engine driving force.

Specifically, the target acceleration setting section 52A
The target acceleration base value GXT _B which is set based on the vehicle speed V and the road gradient SL, to calculate the target acceleration GXT by adding a target acceleration learned value GXT _L set based on the driver's driving operation The target acceleration GXT is represented by the following equation (1). GXT = GXT _B + GX _L (1) where the target acceleration GXT is the target acceleration upper limit GXT _CLU
In the case of (GXT ≧ GXT _CLU ), the target acceleration GXT is set to the target acceleration upper limit GXT _CLU . On the other hand, when the target acceleration GXT is equal to or smaller than the target acceleration lower limit GXT _CLL (GXT ≦ GXT _CLL ), the target acceleration GXT is set to the target acceleration lower limit GXT _CLL . By thus setting the upper limit and the lower limit for the target acceleration GXT, control is simplified and stabilized.

Here, the target acceleration base value GXT _B is
The vehicle speed V and the road gradient SL are set as shown by shading in the three-dimensional coordinates in FIG. That is, the vehicle speed V
Target accelerations GXB ₁₁ , GXB ₁₂ , set based on the specific values V ₁ , V ₂ of the road and the specific values SL ₁ , SL _{2 of the} road gradient SL
GXB ₂₁ and GXB ₂₂ are obtained by multiplying each of the speed coefficient K _V and the road gradient coefficient K _SL by the following equation (2).
It is represented by

[0019] Here, when calculating the target acceleration base value GXT _B is the vehicle speed coefficient K _V is the vehicle speed V, the first predetermined vehicle speed V _1, is calculated on the basis of a second predetermined vehicle speed _{V 2 (V 2> V 1} ) [K _V = (V−V ₁ ) / (V ₂ −V ₁ )]. Further, the road slope coefficient K _SL is the road slope SL, the first predetermined road slope SL ₁ ,
[K _SL = (SL−SL ₁ ) / (SL ₂ −S) calculated based on the second predetermined road gradient SL ₂ (SL ₂ > SL ₁ )
L ₁ )].

GXT_B= (1-K_V) ・ (1-K_SL) ・ GXB₁₁ + K_V・ (1-K_SL) ・ GXB₁₂ + (1-K_V) ・ K_SL・ GXB_{twenty one} + K_V・ K_SL・ GXB_{twenty two} ... (2) The vehicle speed coefficient K_VIs smaller than 0 (K_V<0) is
Vehicle speed coefficient K_VIs 0 and the vehicle speed coefficient K_VIs greater than 1
(K_V> 1) is the vehicle speed coefficient K_VIs 1. In addition, road
Distribution coefficient K_SLIs smaller than 0 (K_SL<0) is road slope
Distribution coefficient K_SLIs 0 and the road gradient coefficient K_SLIs greater than 1
If not (K_SL> 1) is the road gradient coefficient K _SLIs 1.

Specifically, the target acceleration setting section 52A is
Configured as comprising a three-dimensional map for target acceleration setting related to the target acceleration base value GXT _B with respect to the vehicle speed V and the road gradient SL, as shown in FIG. 3, the target on the basis of the map for the target acceleration setting Acceleration base value GXT
_It is preferable to set _B. The learning correction unit 52B controls the target acceleration GXT so that the operating state of the engine brake during traveling on a downhill road can be controlled according to the driver's preference.
Learning correction.

[0022] Specifically, the learning correction section 52B, based on the excess or deficiency determination of engine braking by excess or shortage determination unit 52C to be described later, the target acceleration GXT (GXT by increasing or decreasing correcting the target acceleration learned value GXT _L of the = GXT
_B + GXT _L) is adapted to increase or decrease the. For example, when the engine brake is determined to excess is adapted to increase corrects the target acceleration learned value GXT _L by the following equation. EP is a predetermined minute value.

GXT_{L (NEW)}= GXT_{L (OLD)}+ EP (3) Conversely, when it is determined that the engine brake is insufficient,
The target acceleration learning value GXT is calculated by the following equation._LI will compensate
Swelling. GXT_{L (NEW)}= GXT_{L (OLD)}−EP (4) and the corrected GXT_{L (NEW)}Learning not shown
They are stored in memory. The learning correction unit
In the initial state where learning by 52B has never been performed
Is the target acceleration learning value GXT_LIs a predetermined initial value GXT_L0
Is set to Also, the target acceleration learning value GXT_LTo
Is the upper limit GXT_LHAnd lower limit GXT_LLIs set
In addition, the learning correction unit 52B sets the target acceleration
Learning GXT _LLearning correction. Toes
GXT_{L (NEW)}Is the upper limit GXT_LHBecame larger than
Case (GXT_{L (NEW)}> GXT_LH) Is GXT_{L (NEW)}Up to
Value GXT_LHTo the lower limit GXT_LLSmaller than
(GXT_{L (NEW)}<GXT _LL) Is GXT_{L (NEW)}Below
Limit value GXT_LLSet to. Thus, the target acceleration learning value
GXT_LBy setting upper and lower limits for
It is trying to make it.

The learning result (GXTL _(NEW) ) is retained in the storage means even after the ignition key is turned off. And in the next control,
GXT was in the present control is learning correction by the target acceleration setting unit 52A L _(NEW) is the target acceleration base value GXT _B
And is set as the target acceleration GXT.

The excess / deficiency determining unit 52C determines whether the engine brake is excessive or insufficient based on the driver's operation of requesting acceleration / deceleration of the vehicle, and compares the determination result with the learning correction unit 52B.
Is output to Specifically, the excess / shortage determination unit 52
When the time ratio of deceleration by the brake during driving on a downhill road is small and the time ratio of depressing the accelerator is large, it is determined that the engine brake is excessive, and a signal (excess signal) is sent to the learning correction unit 52B. On the other hand, if the percentage of time during which the accelerator is depressed is small and the percentage of time during which the vehicle is being decelerated by braking is large during traveling on a downhill road, it is determined that the engine brake is insufficient and the learning correction unit 52
A signal (insufficient signal) is output to B.

More specifically, the excess / deficiency judging section 52
In C, the excess / deficiency determination is performed as follows. First, regarding the over-determination, it is premised that the over-determination is started when all of the following over-determination timer count conditions (1) to (5) are satisfied. These excess determination timer count conditions (1) to (5) are for limiting the start time of the excess determination to a steady state when traveling on a downhill road so that accurate determination can be made.

(1) The deceleration operation by the brake is not performed or almost not performed, that is, the longitudinal deceleration (brake deceleration) GXB accompanying the brake operation.
G is smaller than a predetermined learning brake deceleration GXBG _TKG (GXBG <GXBG _{T KG} ). (2) The vehicle speed V is within a predetermined range, that is, the vehicle speed V is a predetermined learning vehicle speed lower limit value V _TKGA (for example, about 10 km / h).
Greater than and less than the predetermined learning speed upper limit V _{TK GB} (e.g., about _{100km / h) (V TKGA <} V <
V _TKGB ).

(3) The road gradient SL is within a predetermined range, that is, the road gradient SL is equal to or lower than the predetermined learned road gradient lower limit value S.
It _should be larger than L _TKGA (for example, about 5%) and smaller than a predetermined upper limit value for learning road SL _SLTKGB (for example, about 10 to 15%) (SL _TKGA <SL <SL _TKGB ). (4) The absolute value of the difference between the longitudinal acceleration GX and the target acceleration GXT is smaller than a predetermined learned downhill road target acceleration deviation GX _TKG (| GXT−GX | <GX _TKG ).

(5) The amount of depression of the accelerator is small, that is, the throttle opening voltage VTH output from the throttle opening sensor (acceleration / deceleration request operation detecting means) 11 is smaller than a predetermined learning throttle opening voltage VTH _TKG. Small (VTH <VTH _TKG ). When the excess determination timer count conditions (1) to (5) are satisfied, the throttle opening voltage VTH is changed to the throttle opening voltage VT.
When it becomes equal to or greater than H _TKG (VTH ≧ VTH _TKG ), the excess / deficiency determination unit 52C starts counting of the excess determination timer TKG.

Then, the next excess determination start condition (1),
When either of the conditions (2) is satisfied, an excessive determination is made as to whether or not the engine brake is excessive. (1) The predetermined time t _{KG has} elapsed from the start of the depression of the accelerator, that is, the count value of the excess determination timer TKG has reached t _KG (TKG = t _KG ). (2) The accelerator has been greatly depressed, that is, the throttle opening voltage VTH is equal to the throttle opening voltage VTH.
VTH _TKGS or higher than _TKG (VTH ≧
VTH _TKGS ).

The above-mentioned excessive determination start condition (1) is for sufficiently sampling data for performing the excessive determination, and the excessive determination start condition (2) is that the accelerator depression amount is large and the engine brake is excessive. When the possibility of the determination is high, the overdetermination is performed even if the predetermined time t _KG has not been reached regardless of the amount of sampling data.

The excess / shortage judging section 52C judges whether or not the following excess judging conditions (1) and (2) are satisfied when any of the above-mentioned excessive judging start conditions (1) and (2) is satisfied.
When all the conditions are satisfied, it is determined that the engine brake is excessive, and a signal (excess signal) is output to the learning correction unit 52B. (1) The ratio of time during which the accelerator is depressed is large, that is, from when the excess determination timer TKG starts counting to when any of the excess determination start conditions (1) and (2) is satisfied. , The ratio TTH of the time during which the throttle opening voltage VTH has _{exceeded the} depression determination throttle opening voltage VTH TTH is a predetermined excess determination depression time ratio T.
Greater than TH _KG (TTH> TTH _KG ).
The depression determination throttle opening voltage VTH _TTH is a threshold value for detecting that the accelerator is depressed greatly, and is set to a value smaller than VTH _TKGs .

(2) Fluctuation width (acceleration width) of the vehicle speed V from the time when the count of the excess determination timer TKG is started to the time when any of the above-mentioned excessive determination start conditions (1) and (2) is satisfied.
Is within a predetermined allowable fluctuation range, that is, the acceleration width VK (VK = _VKGMAX − _VKGMIN ) calculated from the maximum value V _KGMAX and the minimum value V _KGMIN of the vehicle speed V during the above _range is the lower limit value VK. _Must be larger than _{KGA and} smaller than upper limit value VK _KGB (VK _KGA <VK <VK _KGB ). This is because if the acceleration width is too large, there is a possibility that the vehicle has shifted from downhill traveling by engine braking to an acceleration state, and if the acceleration width is small, there is little need to correct the target acceleration GTX. In such a case, the control is simplified and stabilized without performing the learning correction.

Next, the shortage determination by the excess / deficiency determination means 52C will be described. The shortage determination is also based on the assumption that all of the shortage determination timer count conditions (1) to (5) similar to the above-described excess determination timer count conditions (1) to (5) are satisfied. (1) The brake deceleration GXBG is smaller than a predetermined learning brake deceleration GXBG _TFG (GXBG <GXB
G _TFG ).

(2) The vehicle speed V is a predetermined lower limit value V of the learned vehicle speed.
_Must be larger than _{TFGA and} smaller than a predetermined learning vehicle speed upper limit value _VTFGB ( _VTFGA <V < _VTFGB ). (3) The road gradient SL is a predetermined learning road gradient lower limit SL.
_The upper limit SL of the learning road gradient which is larger than _TFGA and is predetermined.
_Be smaller than _TFGB (SL _TFGA <SL <SL _{TF GB} ).

(4) The longitudinal acceleration GX and the target acceleration GXT
The absolute value of the difference between the target acceleration deviation GX and the predetermined
_Be smaller than _TFG (| GXT−GX | <GX _TFG ). (5) The throttle opening voltage VTH is smaller than a predetermined learned throttle opening voltage VTH _TFG (VTH <VT)
H _TFG ). These shortage determination timer count conditions (1)
Each determination value in (5) to (5) may be set to the same value as each determination value in the excess determination timer count conditions (1) to (5).

Then, in a state where the above-mentioned respective shortage determination timer count conditions (1) to (5) are satisfied, a brake deceleration switch (acceleration / deceleration request operation detecting means) 12 linked to a brake lamp (not shown) is turned on. When this happens, the excess / deficiency determination unit 52C starts counting by the shortage determination timer TFG, and when either of the following shortage determination start conditions (1) and (2) is satisfied, the engine brake is activated. Insufficiency determination of whether or not it is insufficient is performed.

(1) The predetermined time t _{FG has} elapsed from the start of the depression of the accelerator, and the count value of the shortage determination timer TFG has reached t _FG (TFG = t _FG ). (2) The brake is depressed greatly, that is, the brake deceleration GXBG is equal to the learning brake deceleration GXBG _TFG
(GXBG ≧ GXBG _TFG ). The shortage determination start condition (1) is for sufficiently sampling data for performing the shortage determination, and the shortage determination start condition (2) is determined to be a large brake depression amount and insufficient engine brake. When the possibility is high, the shortage determination is performed even if the predetermined time _tFG has not been reached regardless of the sampling data amount. In the shortage determination start condition (2), GXBG larger than GXBG _{TFG to} prevent hunting
_TFGS may be used and GXBG ≧ GXBG _TFGS may be used as a condition.

Next, the excess / shortage determining section 52C determines whether or not the following shortage determination conditions (1) and (2) are satisfied when any of the above-described shortage determination start conditions (1) and (2) is satisfied. If all the conditions are satisfied, it is determined that the engine brake is insufficient, and a signal (an insufficient signal) is sent to the learning correction unit 52B.
Is output. (1) The ratio of time during which the brake is depressed is large, that is, from when the shortage determination timer TFG starts counting to when one of the shortage determination start conditions (1) and (2) is satisfied. Is that the ratio TBR of the time when the brake deceleration switch 12 is on is larger than a predetermined shortage determination brake time ratio TBR _FG (TBR).
> TBR _FG ).

(2) Fluctuation range (deceleration range) of the vehicle speed V from the time when the count of the shortage determination timer TFG is started to the time when any of the shortage determination start conditions (1) and (2) is satisfied.
Is within a predetermined allowable fluctuation range, that is, the deceleration width VG (VG = _VFGMAX − _VFGMIN ) calculated from the maximum value V _FGMAX and the minimum value V _FGMIN of the vehicle speed V during the above _range is the lower limit value VG. _{It must} be larger than _{FGA and} smaller than the upper limit value VG _FGB (VG _FGA <VG <VG _FGB ). This is because if the deceleration width is too large, there is a possibility that the vehicle has shifted from downhill traveling by engine braking to a deceleration state by brake operation, and if the deceleration width is small, it is necessary to correct the target acceleration GTX. In such a case, the control is simplified and stabilized without performing learning correction.

The target driving force setting means 53 sets a target driving force FET of the vehicle for realizing the target acceleration GXT set by the target acceleration setting means 52, and corresponds to the target driving force FET. Is output to a target output setting means 54 described later.
Specifically, the target driving force setting means 53 determines the vehicle weight W
And the differential shaft portion inertia equivalent weight W _IDIF and the primary shaft portion inertia equivalent weight W _IPRI multiplied by the square of the gear ratio RAT are added, and the target acceleration GXT set by the target acceleration setting means 52 is added to this. By multiplying, the target acceleration resistance RA [RA = (W + W _IDIF + W _IPRI · R
AT ² ) · GXT], and calculates the weight / gradient resistance R
The target driving force FET is calculated by adding S, the air resistance RL, and the rolling resistance RR, and is represented by the following equation (5).

FET = (W + W _IDIF + W _IPRI · RAT ² ) · GXT + RS + RL + RR (5) The target output setting means 54 is the target driving force setting means 5 described above.
The target output WET of the engine 1 is set so that the target driving force FET set by the control unit 3 is obtained, and the target output WET is output to target primary rotational speed setting means 55 described later.

More specifically, the target output setting means 54 calculates the target driving force FET of the vehicle set by the target driving force setting means 53 by dividing the tire diameter r by the final reduction ratio i _F and the secondary rotation speed. By multiplying by NS, a net target output [FET ／ (r / i _F ) ・ NS] corresponding to the target driving force is calculated, and this net target output is set to the primary rotation speed NP by the input rotation dependent transmission loss torque TLR. Primary loss output (TLR · NP) calculated by multiplication
And the crankshaft inertia torque TIC and the oil pump drive loss torque TLP are added to the engine speed N
E to calculate the engine loss output [(TIC +
TLP) .NE] and the target output WE
T is calculated, and is represented by the following equation (6).

WET = FET ・ (r / i _F ) ・ NS + TLR ・ NP + (TIC + TLP) ・ NE (6) When the load of the compressor for the air conditioner is considered, the compressor load torque TLC is described in the third term. Is multiplied by the engine speed NE. The target primary rotational speed setting means 55 includes a target output WET of the engine 1 set by the above-described target output setting means 54,
The reference rotation speed NE _EB of the engine 1 and the learning reference torque T
The target primary rotational speed NPT is set based on E _EB and output to the primary pulley control means 56.

More specifically, the target primary rotation speed setting means 55 calculates a rotation speed (WET / TE _EB ) corresponding to the target output calculated by dividing the target output WET from the reference rotation speed NE _EB by the reference torque TE _EB. Is subtracted to calculate the target primary rotational speed NPT, and is expressed by the following equation (7). NPT = NE _EB − (WET / TE _EB ) (7) Here, FIG. 4 is an approximation of the output characteristic when the throttle is fully closed with respect to the engine speed by a straight line. Here, the case where the engine rotation speed is low and medium rotation speed is shown.

The reference rotational speed NE _EB is such that the engine output is 0
In this case, the engine speed is the idle speed of the engine, and corresponds to the coordinates of the intersection of the output characteristic of FIG. 4 with the axis indicating the engine speed in the output characteristic when the throttle is fully closed. The reference torque TE _EB is the slope of the output characteristic when the throttle is fully closed in FIG. Specifically, the target primary rotational speed setting means 55 is configured to include a map of engine output characteristics as shown in FIG. 4, and the target primary rotational speed N corresponding to the target output WET is determined using this map.
What is necessary is just to set PT.

The target primary rotational speed NPT is
Primary rotation speed N for overdrive (OD)
The secondary rotation speed N is set so as not to be smaller than P.
S is the overdrive (OD) gear ratio i_ODAlso divided by
(NPT <NS / i_OD), Target plastic
Imari rotation speed NPT is higher than secondary rotation speed NS.
Gear ratio i during ball drive (OD)_ODDivided by
(NPT = NS / i _OD).

When the throttle opening voltage VTH is larger than the target throttle opening voltage VTH _NPT calculated based on the target primary rotational speed NPT (VTH>
VTH _NPT ) and the target primary rotational speed NPT are the previous target primary rotational speed NPT. Here, the target primary rotational speed NPT set by the above equation (5) is calculated by two low-pass filters having filtering cutoff frequencies f _NPT arranged in series with each other.
Filtering is performed in stages to remove minute fluctuation components.

The shift control by the shift control device of the continuously variable transmission according to one embodiment of the present invention configured as described above is performed as shown in the flowchart of FIG. That is, as shown in FIG. 5, in step S10, the downhill road determination means 51 determines whether the vehicle is traveling on a downhill road, and as a result of this determination, when it is determined that the vehicle is traveling on a downhill road, Proceed to step S20.

In step S20, the excess / deficiency judging section 52C
Determines whether the excess determination timer count condition (here, the shortage determination timer count condition is also the same) is satisfied. If the condition is satisfied, the process proceeds to step S30. In step S30, it is determined whether a predetermined time t _KG has elapsed from the start of accelerator depression. When the predetermined time t _KG has elapsed (TKG = t _KG ), the process proceeds to step S70, and when it has not yet elapsed (TKG < t _KG ) in step S40
Proceed to.

In step S40, the magnitude of the accelerator opening, that is, whether the accelerator is depressed greatly is determined.
When the accelerator is depressed greatly (VTH ≧ VTH
The _TKGS) the process proceeds to step S70, when it has not been depressed significantly (VTH <VTH _{TK GS)} in the step S50
Proceed to. In step S50, it is determined whether or not a predetermined time t _FG has elapsed from the start of deceleration by depressing the brake, and when the predetermined time t _FG has elapsed (TFG = t _FG ), the process proceeds to step S90, and when it has not yet elapsed ( TFG =
At t _FG ), the process proceeds to step S60.

In step S60, the brake deceleration GX
The size of BG, that is, whether the brake is depressed greatly is determined. When the brake is depressed greatly (GXB
If (G ≧ GXBG _TFG ), the process proceeds to step S90. If not greatly depressed (GXBG <GXBG _TFG ), the process proceeds to step S110. In step S70, it is determined whether or not the accelerator operation ratio (the ratio of time during which the accelerator is depressed) exceeds a predetermined value, that is, the step-in time ratio TTH.
Is determined to be greater than a predetermined excess determination stepping time ratio TTH _KG , and if it is equal to or less than the excess determination stepping time ratio TTH _KG (TTH ≦ TTH _KG ), the process proceeds to step S
The routine proceeds to 110, but if it is greater than the excess determination stepping time ratio TTH _KG (TTH> TTH _KG ), the excess / shortage determining unit 52C determines that the engine brake is excessive, and proceeds to step S80.

[0053] Then, in step 80, the learning on the learning determination unit section 52B is that, based on the engine brake over determination by excess or shortage determination unit 52C, the target acceleration learned value GXT _L and increasing correction using the above (3) And step S
Proceed to 110. In step S90, it is determined whether or not the brake operation ratio (the ratio of time the brake is depressed) exceeds a predetermined value, that is, whether or not the brake time ratio TBR is larger than a predetermined shortage determination brake time ratio TBR _FG . If it is determined that the brake time is less than the shortage determination brake time ratio TBR _FG (TBR ≦ TBR _FG ), the process proceeds to step S11.
0, but when it is larger than the shortage determination brake time ratio TBR _FG (TBR> TBR _FG ), the excess / shortage determination unit 5
2C determines that the engine brake is insufficient, and determines in step S1
Go to 00.

Then, in step 100, the learning judgment section
The unit 52B is an engine brake by the excess / shortage determining unit 52C.
Based on the shortage determination, the target acceleration learning value GXT_LThe above
The learning is performed after the weight loss is corrected using the equation (3), and the process proceeds to step S
Proceed to 110. Next, in step S110, the target acceleration
The degree setting means 52 determines the vehicle speed V and the road gradient SL (SL = weight ·
Target acceleration base value from slope resistance RS / vehicle weight W)
GXT _BSet.

[0055] Further, in step S120, by adding the target acceleration learning value GXT _L to set target acceleration base value GXT _B at step S110, it sets the target acceleration _{GXT (GXT = GXT B + GXT} L).
The target acceleration learning value GXT _L, when learned by increasing correction by the learning determination unit unit 52B in step S80, the target acceleration learning value is the increase correction GXT
_L , and the learning determination unit 52
When it is learned by decreasing correction by B is the weight loss corrected target acceleration learned value GXT _L, a target acceleration learned value GXT _L learned correction in the previous downhill control otherwise. Thereby, the target acceleration GXT according to the driving state of the driver is set.

In step S130, the target driving force setting means 53 sets the target driving force FET for realizing the target acceleration GXT set in step S120.
Then, in step S140, the target output setting means 54 sets the target output WET so as to become the target driving force FET set in step S130 described above.

Next, the routine proceeds to step S150, where the target primary rotational speed setting means 55 executes the above-described step S1.
The target primary rotational speed NPT is set so that the target output WET set at 40 is obtained. And step S
Proceeding to 160, the primary pulley control means 56 controls the primary pulley 21 so that the actual primary rotation speed NP becomes the target primary rotation speed NPT set in the above-described step S150, in order to control the gear ratio of the primary pulley 21. A feedback control signal corresponding to the amount is set, and a control signal is output to the flow control valve 64. Thus, the gear ratio is controlled such that the actual acceleration becomes the target acceleration GXT set in step S120,
The operation state of the engine brake according to the driver's preference is realized.

If it is determined in step S10 that the vehicle is not traveling on a downhill road, the process proceeds to step S170. In step S170, the target primary rotational speed setting means 55
Sets the target primary rotational speed NPT according to the vehicle speed and the accelerator opening. Then, the process proceeds to step S160, where the primary pulley control unit 56 outputs a feedback control signal corresponding to the control amount of the primary pulley 21 so that the actual primary rotation speed NP becomes the target primary rotation speed NPT set in step S170. After setting, a control signal is output to the flow control valve 64 to control the speed ratio of the primary pulley 21.

[0059] Thus, according to the shift control device of the present continuously variable transmission, when the depression time rate of the accelerator during downhill running is large, the target acceleration learned value GXT _L increasing correction and learning, depression time of the brake when the ratio is large, the learning by decreasing correction target acceleration learned value GXT _L, the target rate GX in accordance with the operating state of the driver
T can be set, and there is an advantage that the operation state of the engine brake according to the driver's preference can be realized.

In particular, a continuously variable transmission cannot determine whether the engine brake is excessive or deficient by an upshift / downshift of a shift lever unlike a stepped automatic transmission.
By monitoring the accelerator operation ratio and the brake operation ratio using the detection signals of the throttle opening sensor 11 and the brake deceleration switch 12 as in the present shift control device,
There is also an advantage that it is possible to accurately determine whether the engine brake is excessive or insufficient.

As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and can be variously modified and implemented without departing from the gist of the present invention. . For example, in the above embodiment, the present invention is described as being applied to a belt type CVT, but the present invention may be applied to other CVTs such as a toroidal type CVT.

[0062]

As described above in detail, according to the transmission control device for a continuously variable transmission of the present invention, when traveling on a downhill road, the target acceleration is set according to the road gradient, and the actual acceleration becomes the target acceleration. In addition to controlling the gear ratio as well as determining whether the engine brake is excessive or insufficient, the target acceleration is learned and corrected based on the determination result, so that the target acceleration according to the driving state can be set, and the driver's preference can be set. There is an advantage that a corresponding operating state of the engine brake can be realized.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a shift control device for a continuously variable transmission according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining an overall configuration of a shift control device for a continuously variable transmission according to an embodiment of the present invention.

FIG. 3 is a diagram for explaining setting of a target acceleration of the shift control device for the continuously variable transmission according to the embodiment of the present invention.

FIG. 4 is a diagram showing output characteristics when the throttle is fully closed with respect to the engine rotation speed of the transmission control device for the continuously variable transmission according to the embodiment of the present invention.

FIG. 5 is a flowchart illustrating a shift control by a shift control device of the continuously variable transmission according to the embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 engine 11 throttle opening sensor (acceleration / deceleration request operation detecting means) 12 brake deceleration switch (acceleration / deceleration request operation detecting means) 20 continuously variable transmission (CVT) 21 primary pulley 50 controller (ECU) 52 target acceleration setting means 52A target Acceleration setting unit 52B Learning correction unit (learning correction unit) 52C Over / under determination unit (over / under determination unit) 56 Primary pulley control unit (speed ratio control unit) 60 Transmission control device

Claims (1)

[Claims] 1. A transmission control device for a continuously variable transmission, which variably controls a speed ratio of a continuously variable transmission connected to an engine to control an operation state of an engine brake when traveling on a downhill road, according to a road gradient. Target speed setting means for setting a target acceleration, a speed ratio control means for controlling a speed ratio of the continuously variable transmission so that the actual acceleration becomes the target acceleration, and an excess / deficiency determining means for determining whether the engine brake is excessive or insufficient. And a learning correction unit for learning and correcting the target acceleration based on the determination by the excess / deficiency determination unit.