JP6921999B2 - Lock-up engagement control device for automatic transmission - Google Patents

Description

The present invention relates to a lockup engagement control device for an automatic transmission that controls engagement of a lockup clutch included in a torque converter interposed between a traveling drive source and a transmission mechanism.

Conventionally, when the lockup clutch is engaged, the belt that corrects the target transmission speed of the belt-type continuously variable transmission to a higher value so that the complete engagement is completed within a predetermined time while limiting the rate of decrease in the engine speed. A control device for a continuously variable transmission is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2010-169227

In the above-mentioned conventional device, the driving force intended by the driver is not taken into consideration in the lockup control, and the lockup clutch is gradually engaged so that the engine speed does not rise regardless of the driving force. I try to do it. Therefore, when the lockup clutch in the released state is engaged, the driving force to be realized by the shift control of the belt-type continuously variable transmission fluctuates depending on the clutch state (engaged / slipped / released) of the lockup clutch, and the operation is performed. There was a problem that it did not become the driving force intended by the person.

The present invention has been made by paying attention to the above problems, and an object of the present invention is to realize a driving force intended by a driver when engaging a lockup clutch in an released state.

In order to achieve the above object, the present invention has a torque converter interposed between the driving drive source for traveling and the transmission mechanism, and the torque converter, and directly connects the torque converter input shaft and the torque converter output shaft by fastening. It includes a lock-up clutch and a lock-up control unit that controls lock-up engagement and lock-up release of the lock-up clutch.
In the lockup engagement control device of this automatic transmission, the lockup control unit estimates the required driving force intended by the driver when engaging the lockup clutch in the released state, and outputs the actual driving force to the drive wheels. Performs slip fastening control that converges to the required driving force.

For example, when the lockup start vehicle speed is set using various parameters, it is necessary to check the actual machine for each of the various parameter conditions for the set value of the lockup start vehicle speed. Further, since one lockup start vehicle speed is substituted for the vehicle performance required by the vehicle manufacturer, it is difficult to set an appropriate lockup start vehicle speed for each vehicle performance.
Focusing on this point, the present inventors considered that it is necessary to directly express the vehicle performance required by the vehicle manufacturer by the lockup fastening control. Therefore, when engaging the lockup clutch in the released state, the lockup control unit that estimates the required driving force intended by the driver and performs slip engagement control in which the actual driving force output to the drive wheels converges to the required driving force. It was adopted.
As a result, when the lockup clutch in the released state is engaged, the driving force intended by the driver can be realized.

FIG. 5 is an overall system diagram showing a drive system and a control system of an engine vehicle to which the lockup engagement control device of the automatic transmission of the first embodiment is applied. It is a shift schedule diagram which shows an example of the D range stepless shift schedule used when the stepless shift control in an automatic shift mode is executed by a variator. It is a main part block diagram which shows the lock-up fastening control device of Example 1. FIG. It is a flowchart which shows the flow of the lock-up fastening control process which is executed in the lock-up control part of the CVT control unit of Example 1. FIG. It is a UNLU estimated driving force calculation block diagram which shows the calculation block of the estimated driving force at UNLU in the lockup fastening control process. It is a LU estimated driving force calculation block diagram which shows the calculation block of the estimated driving force at the time of LU in the lockup fastening control processing. It is an acceleration usable driving force calculation block diagram which shows the calculation block of the acceleration usable driving force in a lockup fastening control process. It is a required torque ratio calculation block diagram which shows the required torque ratio calculation block in the lockup fastening control processing. It is a target engine rotation speed calculation block diagram which shows the calculation block of the driving force required target engine rotation speed in the lockup fastening control processing. It is a time chart showing each characteristic of gear ratio, vehicle speed, engine speed, turbine speed, required driving force, torque ratio, slip ratio, and lockup hydraulic pressure, which represent lockup engagement control in a start scene from a stopped state.

Hereinafter, the best mode for realizing the lockup fastening control device for the automatic transmission of the present invention will be described with reference to the first embodiment shown in the drawings.

First, the configuration will be described.
The lockup engagement control device in the first embodiment is applied to an engine vehicle equipped with a belt-type continuously variable transmission (an example of an automatic transmission) composed of a torque converter, a forward / backward switching mechanism, a variator, and a final deceleration mechanism. Is. Hereinafter, the configuration of the first embodiment will be described separately as "overall system configuration", "lockup fastening control device configuration", and "lockup fastening control processing configuration".

[Overall system configuration]
FIG. 1 shows a drive system and a control system of an engine vehicle to which the lockup engagement control device of the automatic transmission of the first embodiment is applied. Hereinafter, the overall system configuration will be described with reference to FIG.

As shown in FIG. 1, the drive system of the engine vehicle includes an engine 1, a torque converter 2, a forward / backward switching mechanism 3, a variator 4, a final deceleration mechanism 5, and drive wheels 6 and 6. There is. Here, the belt-type continuously variable transmission CVT is configured by incorporating a torque converter 2, a forward / backward switching mechanism 3, a variator 4, and a final deceleration mechanism 5 in a transmission case (not shown).

The engine 1 can control the output torque by an engine control signal from the outside, in addition to controlling the output torque by operating the accelerator by the driver. The engine 1 has an output torque control actuator 10 that controls torque by opening / closing a throttle valve, cutting fuel, or the like.

The torque converter 2 is a starting element by a fluid coupling having a torque increasing function and a torque fluctuation absorbing function. It has a lockup clutch 20 capable of directly connecting the engine output shaft 11 (= torque converter input shaft) and the torque converter output shaft 21 when the torque increasing function and the torque fluctuation absorbing function are not required. The torque converter 2 is provided with a pump impeller 23 connected to the engine output shaft 11 via a converter housing 22, a turbine runner 24 connected to the torque converter output shaft 21, and a one-way clutch 25 in the case. The stator 26 is a component.

The forward / backward switching mechanism 3 is a mechanism that switches the input rotation direction to the variator 4 between a forward rotation direction during forward travel and a reverse rotation direction during reverse travel. The forward / backward switching mechanism 3 includes a double pinion type planetary gear 30, a forward clutch 31 with a plurality of clutch plates, and a reverse brake 32 with a plurality of brake plates. The forward clutch 31 is hydraulically engaged by the forward clutch pressure Pfc when a forward traveling range such as the D range is selected. The reverse brake 32 is hydraulically engaged by the reverse brake pressure Prb when the reverse travel range such as the R range is selected. The forward clutch 31 and the reverse brake 32 are both released by draining the forward clutch pressure Pfc and the reverse brake pressure Prb when the N range (neutral range) is selected.

The variator 4 has a primary pulley 42, a secondary pulley 43, and a pulley belt 44, and steplessly changes the gear ratio (ratio of variator input rotation to variator output rotation) by changing the belt contact diameter. It has a shifting function. The primary pulley 42 is composed of a fixed pulley 42a and a slide pulley 42b arranged coaxially with the variator input shaft 40, and the slide pulley 42b slides by the primary pressure Ppri guided to the primary pressure chamber 45. The secondary pulley 43 is composed of a fixed pulley 43a and a slide pulley 43b arranged coaxially with the variator output shaft 41, and the slide pulley 43b slides by a secondary pressure Psec guided to the secondary pressure chamber 46. The pulley belt 44 is hung on the V-shaped sheave surface of the primary pulley 42 and the V-shaped sheave surface of the secondary pulley 43. The pulley belt 44 is formed of two sets of laminated rings in which a large number of annular rings are stacked from the inside to the outside and a punched plate material, and a large number of ring-shaped laminated rings are attached by sandwiching the two sets of laminated rings. It is composed of elements. The pulley belt 44 may be a chain type belt in which a large number of chain elements arranged in the pulley traveling direction are connected by pins penetrating in the pulley axial direction.

The final deceleration mechanism 5 is a mechanism that decelerates the variator output rotation from the variator output shaft 41, gives a differential function, and transmits the differential function to the left and right drive wheels 6 and 6. As a reduction gear mechanism, the final reduction gear mechanism 5 includes an output gear 52 provided on the variator output shaft 41, an idler gear 53 and a reduction gear 54 provided on the idler shaft 50, and a final gear provided at the outer peripheral position of the differential case. It has a gear 55 and. Then, as the differential gear mechanism, it has a differential gear 56 interposed between the left and right drive shafts 51 and 51.

As shown in FIG. 1, the control system of the engine vehicle includes a hydraulic control unit 7 representing a hydraulic control system and a CVT control unit 8 representing an electronic control system.

The hydraulic control unit 7 applies a primary pressure Ppri guided to the primary pressure chamber 45, a secondary pressure Psec guided to the secondary pressure chamber 46, a forward clutch pressure Pfc to the forward clutch 31, a reverse brake pressure Prb to the reverse brake 32, and the like. It is a unit that regulates pressure. The flood control unit 7 includes an oil pump 70 that is rotationally driven by an engine 1 that is a driving drive source for traveling, and a flood control circuit 71 that regulates various control pressures based on the discharge pressure from the oil pump 70. .. The hydraulic control circuit 71 includes a line pressure solenoid valve 72, a primary pressure solenoid valve 73, a secondary pressure solenoid valve 74, a select solenoid valve 75, and a lockup pressure solenoid valve 76. The solenoid valves 72, 73, 74, 75, 76 adjust to each command pressure according to the control command value output from the CVT control unit 8.

The line pressure solenoid valve 72 adjusts the discharge pressure from the oil pump 70 to the commanded line pressure PL according to the line pressure command value output from the CVT control unit 8. This line pressure PL is the original pressure when adjusting various control pressures, and is a hydraulic pressure that suppresses belt slippage and clutch slippage with respect to the torque transmitted to the drive system.

The primary pressure solenoid valve 73 adjusts the pressure reduction to the commanded primary pressure Ppri with the line pressure PL as the original pressure according to the primary pressure command value output from the CVT control unit 8. The secondary pressure solenoid valve 74 adjusts the pressure reduction to the secondary pressure Psec commanded with the line pressure PL as the original pressure according to the secondary pressure command value output from the CVT control unit 8.

The select solenoid valve 75 adjusts the pressure reduction to the forward clutch pressure Pfc or the reverse brake pressure Prb commanded with the line pressure PL as the original pressure according to the forward clutch pressure command value or the reverse brake pressure command value output from the CVT control unit 8. do.

The lockup pressure solenoid valve 76 adjusts the lockup control pressure PL / U for engaging / slip engaging / releasing the lockup clutch 20 according to the lockup pressure command value output from the CVT control unit 8.

The CVT control unit 8 performs line pressure control, shift control, forward / backward switching control, lockup control, and the like. In the line pressure control, a command value for obtaining a target line pressure according to the accelerator opening or the like is output to the line pressure solenoid valve 72. In shift control, when the target gear ratio (target primary rotation speed Npri ^* ) is determined, the command value for obtaining the determined target gear ratio (target primary rotation speed Npri ^* ) is set to the primary pressure solenoid valve 73 and the secondary pressure solenoid valve 74. Output to. In the forward / backward switching control, a command value for controlling engagement / release of the forward clutch 31 and the reverse brake 32 is output to the select solenoid valve 75 according to the selected range position. In the lockup control, a command value for controlling the lockup control pressure PL / U that engages / engages / releases the lockup clutch 20 is output to the lockup pressure solenoid valve 76.

The CVT control unit 8 includes a primary rotation sensor 80, a vehicle speed sensor 81, a secondary pressure sensor 82, an oil temperature sensor 83, an inhibitor switch 84, a brake switch 85, an accelerator opening sensor 86, a primary pressure sensor 87, and a turbine rotation sensor 89. Sensor information and switch information from the secondary rotation sensor 90 and the like are input. Further, sensor information from the engine rotation sensor 12 is input to the engine control unit 88. For example, the CVT control unit 8 inputs engine torque information from the engine control unit 88 and outputs an engine torque request to the engine control unit 88. The CVT control unit 8 and the engine control unit 88 are connected by a CAN communication line 13 so that information can be exchanged.

FIG. 2 shows an example of a D-range continuously variable transmission schedule used when the variator 4 executes continuously variable transmission control in the automatic transmission mode when the D-range is selected.

The "D range shift mode" is an automatic shift mode in which the gear ratio is automatically and steplessly changed according to the driving state of the vehicle. The shift control in the "D range shift mode" is performed by the operating point (the operating point on the D range continuously variable transmission schedule of FIG. 2) specified by the vehicle speed VSP (vehicle speed sensor 81) and the accelerator opening APO (accelerator opening sensor 86). VSP, APO) determines the target primary rotation speed Npri ^* . Then, the primary rotation speed Npri from the primary rotation speed sensor 80 is controlled by the pulley hydraulic control to match the ^{target primary rotation speed Npri *.}

That is, as shown in FIG. 2, the D-range continuously variable transmission schedule used in the "D-range continuously variable transmission mode" has a gear ratio range of the lowest gear ratio and the highest gear ratio according to the operating point (VSP, APO). It is set to change the gear ratio steplessly within the range. For example, when the vehicle speed VSP is constant, when the accelerator is depressed, the target primary speed Npri ^* rises and shifts in the downshift direction, and when the accelerator is returned, the target primary speed Npri ^* decreases and rises. Shift in the shift direction. When the accelerator opening APO is constant, the gear shifts in the upshift direction when the vehicle speed VSP increases, and shifts in the downshift direction when the vehicle speed VSP decreases.

[Lockup fastening control device configuration]
FIG. 3 shows the lockup fastening control device of the first embodiment. Hereinafter, the lockup fastening control device configuration will be described with reference to FIG.

As shown in FIG. 3, the lockup engagement control device includes a lockup clutch 20, a lockup solenoid valve 76, and a lockup control unit 8a. The main sensors and switches that provide input information to the lockup control unit 8a include an engine rotation sensor 12, a vehicle speed sensor 81, an inhibitor switch 84, an accelerator opening sensor 86, a turbine rotation sensor 89, and the like. It has.

The lockup clutch 20 is provided in parallel with the torque converter 2. When the select lever 91 performs a select operation from the N range to the D range to start the vehicle, the lockup clutch 20 in the released state at the start of starting is engaged by the lockup engagement control that shifts from slip engagement to complete engagement. On the contrary, the lockup clutch 20 in the engaged state during the D range traveling is released when the vehicle speed drops to the lockup release vehicle speed.

The lock-up solenoid valve 76 is a valve that controls the differential pressure (lock-up control pressure PL / U) of the lock-up clutch 20 according to a command value from the CVT control unit 8. Make it a state.

The lockup control unit 8a is provided in the CVT control unit 8 which is an electronic control device of the belt-type continuously variable transmission, and performs lockup engagement control processing and lockup release control processing. In the lockup engagement control process, when the lockup clutch 20 in the released state is engaged, the required driving force intended by the driver is estimated, and the actual driving force output to the drive wheels 6 converges to the required driving force. Take control.

The engine rotation sensor 12 is a sensor that detects the engine rotation speed Ne, which is the rotation of the crankshaft of the engine 1, by the pulse count number, which is the count number of pulse wave signals. The engine speed Ne corresponds to the input speed of the torque converter 2.

The turbine rotation sensor 89 is a sensor that detects the turbine rotation speed Nt, which is the rotation of the torque converter output shaft 21 connected to the turbine runner 24 of the torque converter 2, by the pulse count number, which is the count number of pulse wave signals. This turbine rotation speed Nt corresponds to the output rotation speed of the torque converter 2.

The inhibitor switch 84 detects the range position (P range, R range, N range, D range, L range) selected by the select lever 91, and outputs a range position signal according to the range position. The select operation by the driver is detected by monitoring the range position signal from the inhibitor switch 84. The select operation by the driver includes not only the operation by the select lever 91 but also the operation by the select switch or the like.

The vehicle speed sensor 81 detects the vehicle speed VSP, which is the vehicle speed when the engine vehicle is traveling. The accelerator opening sensor 86 detects the accelerator opening APO, which is the amount of accelerator operation by the driver.

[Lockup fastening control processing configuration]
FIG. 4 shows the flow of the lockup engagement control process executed by the lockup control unit 8a of the CVT control unit 8 of the first embodiment. Hereinafter, each step of FIG. 4 showing the lockup fastening control processing configuration of the first embodiment will be described. In addition, "LU" is an abbreviation for "lockup", "UNLU" is an abbreviation for "unlockup", and "UNLU" is a state in which the lockup clutch 20 does not transmit torque. show.

In step S1, it is determined whether or not the state of the lockup clutch 20 is a state other than the LU engagement. If YES (state other than LU conclusion), the process proceeds to step S2, and if NO (LU conclusion state), the process proceeds to step S13.

Here, the "state other than LU engagement" means that the lockup clutch 20 is in the released state or the slip engagement state. The “LU engaged state” means an engaged state in which the lockup clutch 20 does not allow the occurrence of differential rotation. That is, when the engagement hydraulic pressure is applied to the lockup clutch 20, and the clutch input rotation speed and the clutch output rotation speed match, the "LU engagement state" is determined, and at other times, the "state other than LU engagement state" is determined. Is judged.

In step S2, following the determination that the state is other than the LU engagement in step S1, the UNLU estimated driving force Funlu at the time of UNLU is calculated, and the process proceeds to step S3.

Here, the UNLU estimated driving force Funlu is calculated using the UNLU driving force characteristic in which the torque ratio of the torque converter 2 contributes when the lockup clutch 20 is released, as shown in FIG. In block B1, the turbine speed Nt and the engine speed Ne are input, and the speed ratio TCRTO is calculated by the formula TCRTO = Nt / Ne. In block B2, the speed ratio TCRTO is input, and the torque capacity coefficient TCTAU is calculated using the relational characteristics between the speed ratio TCRTO and the torque capacity coefficient τ. In block B3, the speed ratio TCRTO is input, and the torque ratio TCTRQRTO is calculated using the relational characteristics between the speed ratio TCRTO and the torque ratio T. In block B4, the engine speed Ne and the torque capacity coefficient TCTAU are input, and the input shaft torque Tin is calculated by the formula of Tin = τNe ^ 2. In block B5, the input shaft torque Tin, the torque ratio TCTRQRTO, and the unit friction TRQ are input, and the output shaft torque Tout is calculated by multiplying these. In block B6, the output shaft torque Tout, the final gear ratio Final, the vehicle weight M vehicle, and the tire diameter Rtire are input, and the UNLU estimated driving force Funlu is calculated by the formula of Funlu = (Tout × Final) / (Mvehicle × Rtire).

In step S3, following the calculation of the UNLU estimated driving force Funlu in step S2, the LU estimated driving force Flu at the time of LU is calculated, and the process proceeds to step S4.

Here, the LU estimated driving force Flu is calculated using the LU driving force characteristic in which the torque ratio of the torque converter 2 does not contribute when the lockup clutch 20 is engaged, as shown in FIG. In block B7, the turbine speed Nt (= engine speed Ne) and the accelerator opening APO are input, and the engine torque Te is estimated using the engine torque total performance characteristics with the engine speed Ne and the accelerator opening APO as parameters. calculate. In block B8, the engine torque Te, the engine torque Teng acquired by the CAN communication line, and other engine torque information Teng_target, LUcluchstatus are input, and for example, the engine torque estimated value Te # is obtained by selecting the minimum value. In block B9, the engine torque estimated value Te #, the engine inertia shuttle engine INATRQ, and the oil pump loss torque OilpomplossTRQ are input, and the input shaft torque Tin is calculated by the formula of Tin = (Te # −EngineINATRQ−OilpomplossTRQ). In block B10, the actual gear ratio RATIO, the input shaft torque Tin, and the unit friction torque unitfrictionTRQ are input, and the output shaft torque Tout is calculated by multiplying these. In block B11, the output shaft torque Tout, the final gear ratio Final, the vehicle weight M vehicle, and the tire diameter Rtire are input, and the LU estimated driving force Flu is calculated by the formula Flu = (Tout × Final) / (M vehicle × Rtire).

In step S4, following the calculation of the LU estimated driving force Flu in step S3, the running resistance estimated value Fresis is calculated, and the process proceeds to step S5.

Here, the estimated running resistance Fresis is calculated using the running resistance characteristics with respect to the vehicle speed VSP and the like, as shown in FIG. In block B12, the road surface gradient GRADE and the vehicle speed VSP are input, and the basic traveling resistance Fresisb is calculated using the relational characteristics of the road surface gradient and the traveling resistance with respect to the vehicle speed. In block B13, the vehicle speed VSP and the accelerator opening APO are input, and the traveling resistance correction value Fv is calculated using the traveling resistance correction characteristics for the vehicle speed and the accelerator opening. In block B14, the basic running resistance Fresisb and the running resistance correction value Fv are input, and the running resistance Fresis is calculated by the formula Fresis = (Fresisb + Fv).

In step S5, following the calculation of the running resistance estimated value Fresis in step S4, the acceleration usable driving force Fmarg is calculated, and the process proceeds to step S6.

Here, the acceleration usable driving force Fmarg is calculated as a margin driving force that can be used for vehicle acceleration at UNLU, as shown in FIG. That is, in the block B15, the estimated driving force Funlu at UNLU and the running resistance Fresis are input, and the acceleration usable driving force Fmarg is calculated by the formula of Fmarg = (Funlu-Fresis).

In step S6, following the calculation of the acceleration usable driving force Fmarg in step S5, the opening margin ratio MargineRate is calculated, and the process proceeds to step S7.

Here, as shown in FIG. 8, the opening margin ratio MargineRate is used as a ratio of the acceleration usable driving force Fmarg that can be used for vehicle acceleration at UNLU to the actual driving force based on the driving force requested by the driver. Calculated. That is, in the block B16, the accelerator opening APO representing the required driving force from the driver is input, and the opening margin rate Margine Rate (maximum value = 1) is calculated using the fuel efficiency performance contribution characteristic and the power performance contribution characteristic. do. The fuel efficiency performance contribution characteristic is the maximum value when the accelerator opening APO is zero, and is given by the characteristic that it becomes smaller as the accelerator opening APO becomes larger. The power performance contribution characteristic is zero when the accelerator opening APO is zero, and is given by a characteristic that increases as the accelerator opening APO increases. As the opening margin ratio, for example, as shown in FIG. 8, two characteristics are set in advance, and when the driver selects the fuel consumption mode, the fuel consumption performance contribution characteristic is selected, and the driver selects the fuel consumption performance contribution characteristic. When the sport mode is selected, the power performance contribution characteristic may be selected. Further, as the opening margin ratio, for example, one characteristic based on the intermediate characteristic between the fuel efficiency performance contribution characteristic and the power performance contribution characteristic is set in advance, and one characteristic is set according to the performance required by the vehicle manufacturer. It may be set as an important characteristic or a power performance-oriented characteristic.

In step S7, following the calculation of the opening margin rate Margine Rate in step S6, the opening allocation driving force Frate is calculated, and the process proceeds to step S8.

Here, as shown in FIG. 8, the opening degree allocation driving force Frate indicates the driving force allocated to obtain the driving performance intended by the driver among the acceleration usable driving force Fmarg at the time of UNLU. That is, in the block B17, the acceleration usable driving force Fmarg and the opening margin rate MargineRate are input, and the opening allocation driving force Frate is calculated using the formula of Frate = (Fmarg × MargineRate).

In step S8, following the calculation of the opening degree allocation driving force Frate in step S7, the required driving force Ft is calculated, and the process proceeds to step S9.

Here, as shown in FIG. 8, the required driving force Ft indicates a driving force obtained by converting the opening degree allocation driving force Frate into the driving wheels 6. That is, in the block B18, the opening allocation driving force Frate, the final gear ratio Final, the vehicle weight M vehicle, and the tire diameter Rtire are input, and the required driving force Ft is calculated by the formula of Ft = (Frate × Final) / (M vehicle × Rtire). calculate.

In step S9, following the calculation of the required driving force Ft in step S8, the required torque ratio Tt on the turbine shaft is calculated, and the process proceeds to step S10.

Here, as shown in FIG. 8, the required torque ratio Tt increases the slip amount of the lockup clutch 20 as the required driving force Ft increases, and becomes a large value for ensuring the torque increasing action in the torque converter 2. That is, in the block B19, the required driving force Ft and the LU estimated driving force Flu at the time of LU are input, and the required torque ratio Tt is calculated by the formula of Tt = (Ft / Flu).

In step S10, following the calculation of the required torque ratio Tt in step S9, the required speed ratio TCRTOt is calculated, and the process proceeds to step S11.

Here, the required speed ratio TCRTOt is a value obtained by converting the required torque ratio Tt into a speed ratio using the performance characteristics of the torque converter 2 in order to make it controllable by lockup control, as shown in FIG. That is, in the block B20, the required torque ratio Tt is input, and the required speed ratio TCRTOt is calculated using the relational characteristics between the torque ratio and the speed ratio of the torque converter 2. When converting the required torque ratio Tt to the required speed ratio TCRTOt, the relationship characteristics between the torque ratio and the speed ratio of the torque converter 2 are set in consideration of the thermal performance due to the slip of the lockup clutch 20.

In step S11, following the calculation of the required speed ratio TCRTOt in step S10, the driving force required target engine speed Neng_target is calculated, and the process proceeds to step S12.

Here, the driving force required target engine speed Neng_target is a value obtained by converting the required speed ratio TCRTOt for obtaining the driver's required driving force into the engine speed, as shown in FIG. That is, in the block B21, the required speed ratio TCRTOt and the turbine speed Nt are input, and the driving force required target engine speed Neng_target is calculated using the equation of Neng_target = (Nt / TCRTOt).

In step S12, following the calculation of the driving force required target engine speed Neng_target in step S11, a lockup is concluded by engine speed feedback control so that the actual engine speed Ne converges to the driving force required target engine speed Neng_target. Take control and proceed to return.

In step S13, following the determination that the LU is in the LU engagement state in step S1, the lockup release control is executed, and the process proceeds to return.

Here, in the "lock-up release control", for example, the lock-up release vehicle speed is set in advance based on the experimental results, or is calculated so as to satisfy a given predetermined condition. Then, when the actual vehicle speed reaches the lockup release vehicle speed during deceleration running, the lockup clutch 20 is released at a predetermined hydraulic relief gradient.

Next, the action will be described.
The operation of the first embodiment will be described separately for "problems and problem solving methods of lockup fastening control", "lockup fastening control processing action", and "lockup fastening control action in a starting scene".

[Problems of lockup fastening control and problem solving methods]
In the conventional lockup engagement control, the lockup start vehicle speed, which is the start point of lockup engagement, is set for each vehicle type using various parameters such as accelerator opening, vehicle speed, rotation, torque, range information, and gear stage. Was. Then, in the starting scene or the like, when the vehicle speed reaches the lockup start vehicle speed, the lockup clutch slip engagement is started.

However, since the conventional lockup engagement control is a control for determining the start point of the lockup engagement with various parameters, it takes a lot of man-hours to confirm when setting the lockup start vehicle speed, and setting mistakes occur frequently. There was a problem. That is, it is necessary to check the actual machine under various parameter conditions, and one lockup start vehicle speed is set as a substitute for the vehicle performance required by the vehicle manufacturer, so the vehicle performance is checked while tuning. , The experimental man-hours were also enormous.

(A) In order to solve the above problems, it is necessary to directly express the vehicle performance required by the vehicle manufacturer by lock-up fastening control. Therefore, it was decided to use the driving force characteristics and running resistance characteristics of the vehicle for lockup fastening control.

(B) In order to estimate the driving force required for lockup control, the driving force characteristic α when the LU is OFF and the driving force characteristic β when the LU is ON are set in advance. The driving force characteristic α is a characteristic when the torque ratio of the torque converter contributes, and the driving force characteristic β is a characteristic when the torque ratio of the torque converter does not contribute. The reason for this is that when the two driving force characteristics α and β are preset, the limit driving force in each state when the LU is OFF and when the LU is ON can be defined.

(C) Since the states of driving force characteristic α and driving force characteristic β are selected and instructed to lockup engagement control, the power performance of vehicle performance (close to driving force characteristic α) and fuel efficiency performance (driving force characteristic β) It was decided to distribute the ratio according to the accelerator opening. In other words, the requirements for lockup engagement control are assigned from the power performance and fuel efficiency performance.

(D) After calculating the target driving force by considering the driving force characteristic α, the driving force characteristic β, and the opening allocation ratio, the current running resistance is calculated as the gradient estimated value, the vehicle speed, the vehicle weight, the tire diameter, and other vehicle specifications. Estimate using and compare with the target driving force. Here, if the running resistance is higher than the above-mentioned target driving force, the driving force loses to the running resistance, so the running resistance is output as the target driving force. As a result, it is possible to optimize the lockup engagement / release during slope driving.

(E) Calculate the target torque ratio by dividing the target driving force by the estimated driving force when the LU is ON when the current conclusion is concluded. This makes it possible to estimate the torque ratio currently required.

(F) It is necessary to set the target rotation speed so that it can be controlled by lockup fastening control. Therefore, the target torque ratio is converted to the target speed ratio based on the fluid performance of the torque converter. The target engine speed can be calculated by dividing the target speed ratio by the turbine speed.

[Lockup fastening control processing action]
Hereinafter, the lockup fastening control processing operation that embodies the above-mentioned problem solving method will be described based on the flowchart shown in FIG.

When the lockup clutch 20 is in the released state, the process proceeds to step S1 → step S2 → step S3 → step S4 → step S5 → step S6 → step S7 → step S8 → step S9 → step S10 → step S11.

In step S2, as shown in FIG. 5, UNLU uses the UNLU driving force characteristic (= capacitance coefficient characteristic and torque ratio characteristic of the torque converter 2) to which the torque ratio of the torque converter 2 contributes when the lockup clutch 20 is released. The estimated driving force Funlu is calculated.

In step S3, as shown in FIG. 6, the LU estimated driving force Flu is calculated using the LU driving force characteristic (= engine torque total performance characteristic) in which the torque ratio of the torque converter 2 does not contribute when the lockup clutch 20 is engaged. Will be done.

In step S4, as shown in FIG. 7, the estimated running resistance Fresis is calculated using the running resistance characteristic with respect to the vehicle speed VSP and the like.

In step S5, as shown in FIG. 7, the acceleration usable driving force Fmarg, which is the margin driving force that can be used for vehicle acceleration at UNLU, is calculated.

In step S6, as shown in FIG. 8, the opening margin ratio Margine Rate, which is the ratio of the acceleration usable driving force Fmarg that can be used for vehicle acceleration during UNLU to the actual driving force based on the driving force requested by the driver. Is calculated.

In step S7, as shown in FIG. 8, the opening degree allocation driving force Frate indicating the driving force allocated to obtain the driving performance intended by the driver among the acceleration usable driving force Fmarg at UNLU is calculated.

In step S8, as shown in FIG. 8, the required driving force Ft indicating the driving force obtained by converting the opening degree allocation driving force Frate into the driving wheels 6 is calculated.

In step S9, as shown in FIG. 8, the required torque ratio Tt is calculated, which increases the slip amount of the lockup clutch 20 as the required driving force Ft increases, and becomes a large value for ensuring the torque increasing action in the torque converter 2. NS.

In step S10, as shown in FIG. 9, the required speed ratio TCRTOt, which is a value obtained by converting the required torque ratio Tt into a speed ratio using the performance characteristics of the torque converter 2, is calculated in order to make it controllable by lockup control. Will be done.

In step S11, as shown in FIG. 9, the driving force required target engine speed Neng_target, which is a value obtained by converting the required speed ratio TCRTOt for obtaining the driver's required driving force into the engine speed, is calculated.

Then, the process proceeds from step S11 to step S12, and in step S12, lockup engagement control by engine speed feedback control is executed so that the actual engine speed Ne converges to the driving force required target engine speed Neng_target.

After that, the process proceeds to step S1 → step S2 → step S3 → step S4 → step S5 → step S6 → step S7 → step S8 → step S9 → step S10 → step S11 until the lockup clutch 20 is determined to be engaged. The flow is repeated.

When it is determined that the lockup clutch 20 is in the engaged state, the flow of step S1 → step S13 → return is repeated, and in step S13, the lockup release control is executed. In the lockup release control, the engaged state of the lockup clutch 20 is maintained during traveling at an actual vehicle speed exceeding the lockup release vehicle speed. Then, when the vehicle enters deceleration and the actual vehicle speed drops below the lockup release vehicle speed, the lockup clutch 20 is released at a predetermined hydraulic relief gradient. When the lockup clutch 20 is released, the lockup engagement control shifts to the lockup engagement control.

In this way, in the lockup engagement control processing action, the driving force when the LU is OFF can be calculated from the engine performance, the torque converter performance, the shift line, the vehicle weight, and the tire diameter. After calculating the running resistance there, the remaining driving force that can be used for acceleration is calculated. The target driving force is defined for each accelerator opening from the surplus driving force that can be used for acceleration (determined from fuel efficiency and power performance requirements). From there, the torque ratio of the torque converter share is taken into consideration to calculate the driving force required target engine speed.

Therefore, when the actual vehicle speed reaches the lockup start vehicle speed as in the case of setting the lockup start vehicle speed, the lockup engagement control is not started, but the slip engagement start according to the driving force required by the driver. Timing and slip fastening control.

That is, when the driving force required by the driver is large, the slip engagement start timing at which the lockup clutch 20 starts to have the engagement capacity is delayed, the slip amount is large, and the slip engagement section becomes long. That is, after the torque ratio of the torque converter share is kept large for a long time by the slip fastening control, the control is performed to shift to the fastening state. On the contrary, when the driving force required by the driver is small, the slip engagement start timing at which the lockup clutch 20 starts to have the engagement capacity is early, the slip amount is small, and the slip engagement section becomes short. That is, after the torque ratio of the torque converter share is reduced at an early stage by the slip fastening control, the control is performed to shift to the fastening state.

[Lock-up fastening control action in the starting scene]
FIG. 10 is a time chart showing each characteristic showing the lockup engagement control in the starting scene from the stopped state. Hereinafter, the lockup fastening control action in the starting scene will be described with reference to FIG.

When the select operation from the N range to the D range is performed at time t0, the lockup hydraulic pressure starts to rise from time t0 as shown in the lockup hydraulic characteristics. Then, when the accelerator is depressed at time t1 with the intention of starting from a stop, the engine speed, turbine speed, driving force, and torque ratio start to rise sharply.

Immediately after the engine speed starts to rise sharply at time t1, the driving force and torque ratio reach their peak. When the driving force and torque ratio reach the peak, the vehicle starts to start at time t2 immediately after that, as shown in the vehicle speed characteristics. Further, when the driving force and the torque ratio reach the peak, the driving force and the torque ratio then decrease in a smooth curve.

The lockup clutch 20, which is in the released state while the vehicle is stopped, starts slip engagement immediately after the time t1, and is in the engaged state at the time t3 at the intermediate position where the driving force and the torque ratio decrease in a smooth curve. The upshift starts immediately before the time t3, and after the time t3, the vehicle speed increases with the upshift in the locked-up concluded state.

That is, the section from the time t1 to the time t3 is the slip engagement section of the lockup clutch 20 as shown in the slip ratio characteristic. In this slip fastening section, lockup fastening control by engine speed feedback control is executed so that the actual engine speed Ne converges to the driving force required target engine speed Neng_target.

Therefore, looking at the engine speed characteristics, as shown in the frame surrounded by the arrow C, the engine speed characteristics in Example 1 due to slip fastening are compared with the engine speed characteristics (broken line) when LU is OFF. (Solid line) suppresses an excessive increase in engine speed. Looking at the driving force characteristics, as shown in the frame surrounded by the arrow D, the driving force characteristics (solid line) in Example 1 are the driving force peak values as compared with the driving force characteristics (broken line) when LU is OFF. Is high, and the generation of unnecessary driving force after the peak elapses is suppressed. Looking at the torque ratio characteristics, as shown in the frame surrounded by the arrow E, the torque ratio characteristics (broken line) show that the torque ratio rises to the peak immediately after time t1 and then a smooth curve toward time t3. Draw and drop.

Next, the effect will be described.
In the lock-up fastening control device for the belt-type continuously variable transmission CVT of the first embodiment, the effects listed below can be obtained.

(1) A torque converter 2 interposed between the driving drive source (engine 1) and the transmission mechanism (variator 4), and
A lockup clutch 20 that is provided in the torque converter 2 and directly connects the torque converter input shaft and the torque converter output shaft by fastening.
A lockup control unit 8a that controls lockup engagement and lockup release of the lockup clutch 20 is provided.
In the lockup engagement control device of this automatic transmission (belt type continuously variable transmission CVT), the lockup control unit 8a estimates the required driving force intended by the driver when engaging the lockup clutch 20 in the released state. Then, slip fastening control is performed so that the actual driving force output to the driving wheels 6 converges to the required driving force.
Therefore, when the lockup clutch 20 in the released state is engaged, the driving force intended by the driver can be realized.

(2) The lockup control unit 8a has an unlock drive force characteristic when the lockup clutch 20 is released, a lockup drive force characteristic when the lockup clutch 20 is engaged, and a running resistance characteristic. And, are used to estimate the required driving force intended by the driver.
Therefore, in addition to the effect of (1), the limit driving force in the released state of the lockup clutch 20 and the engaged state of the lockup clutch 20 is defined, so that the required driving force intended by the driver can be easily estimated. can do.

(3) The lockup control unit 8a calculates the acceleration usable driving force Fmarg from the difference between the estimated driving force Funlu at the time of unlocking based on the unlocking driving force characteristic and the running resistance estimated value Fresis based on the running resistance characteristic.
Calculate the opening margin ratio Margine Rate, which is the ratio of allocating the driving force Fmarg that can be used for acceleration according to the driver's performance required characteristics and the accelerator opening APO.
The opening allocation driving force Frate is calculated by multiplying the acceleration usable driving force Fmarg by the opening margin rate Margine Rate.
Therefore, in addition to the effect of (2), the opening allocation driving force Frate, which indicates the driving force allocated to obtain the driving performance intended by the driver among the acceleration usable driving force Fmarg at the time of unlocking, is accurately performed. Can be calculated.

(4) The lockup control unit 8a has, as the driver's performance required characteristics, the fuel efficiency performance required characteristic that the larger the accelerator opening APO is, the smaller the opening margin ratio Margine Rate is, and the larger the accelerator opening APO is, the more the opening margin ratio is. It has the driving force performance required characteristics that increase the Margine Rate.
Therefore, in addition to the effect of (3), when there is a fuel efficiency performance requirement and a driving force performance requirement as the driver's performance requirement, any performance requirement can be obtained by selecting a characteristic that meets the requirement from the two characteristics. Can also respond to.

(5) The lockup control unit 8a calculates the required driving force Ft by converting the opening degree allocation driving force Frate into the output to the driving wheels 6.
The required torque ratio Tt in the torque converter 2 is calculated by dividing the required driving force Ft by the estimated driving force Flu at the time of lockup based on the lockup driving force characteristic.
Therefore, in addition to the effects of (3) or (4), the required torque ratio Tt, which is an index value for ensuring the torque increasing action in the torque converter 2, is accurately calculated according to the magnitude of the required driving force Ft. be able to.

(6) The lockup control unit 8a converts the required torque ratio Tt into the required speed ratio TCRTOt using the torque converter performance characteristics.
The target running drive source speed (driving force required target engine speed Neng_target) is calculated by dividing the turbine speed Nt by the required speed ratio TCRTOt.
The slip engagement control of the lockup clutch 20 is executed by feedback control that converges the actual driving drive source rotation speed (actual engine rotation speed Ne) to the target traveling drive source rotation speed (driving force required target engine rotation speed Neng_target).
Therefore, in addition to the effect of (5), the slip engagement control of the lockup clutch 20 that realizes the driving force intended by the driver can be executed by the engine speed feedback control with high controllability.

The lockup engagement control device for the automatic transmission of the present invention has been described above based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and design changes and additions are permitted as long as the gist of the invention according to each claim is not deviated from the claims.

In the first embodiment, as the lock-up control unit 8a, the unlock-up driving force characteristic when the lock-up clutch 20 is released, the lock-up driving force characteristic when the lock-up clutch 20 is engaged, the traveling resistance characteristic, and the like. Is used to show an example of estimating the required driving force intended by the driver. However, the lockup control unit may use several patterns of slip lockup driving force characteristics as an example of estimating the required driving force intended by the driver.

In the first embodiment, as the slip engagement control of the lockup clutch 20, an example is shown in which the engine speed feedback control for realizing the driving force intended by the driver is performed. However, as the slip engagement control of the lockup clutch, an example of calculating the difference rotation speed (engine rotation speed-turbine rotation speed) of the lockup clutch and performing the difference rotation speed feedback control to realize the driving force intended by the driver. It may be.

In the first embodiment, an example is shown in which the lockup fastening control device of the present invention is applied to an engine vehicle equipped with a belt-type continuously variable transmission CVT as an automatic transmission. However, the lockup engagement control device of the present invention may be applied as an automatic transmission to a vehicle equipped with a stepped transmission called a step AT, a vehicle equipped with a continuously variable transmission with an auxiliary transmission, or the like. Further, the applicable vehicle is not limited to an engine vehicle, but can also be applied to a hybrid vehicle in which an engine and a motor are mounted as a driving drive source, an electric vehicle in which a motor is mounted as a driving drive source, and the like.

Claims (5)

A torque converter installed between the driving drive source and the transmission mechanism,
A lockup clutch that is provided in the torque converter and directly connects the torque converter input shaft and the torque converter output shaft by fastening.
A lockup control unit that performs lockup engagement control and lockup release control of the lockup clutch,
In the lock-up fastening control device of an automatic transmission equipped with
When the lockup control unit engages the lockup clutch in the released state, the lockup control unit has an unlocking driving force characteristic in the released state of the lockup clutch and a lock in the state in which the lockup clutch is engaged. The up-driving force characteristic and the running resistance characteristic are used to estimate the required driving force intended by the driver, and slip fastening control is performed so that the actual driving force output to the drive wheels converges to the required driving force. A featured automatic transmission lock-up engagement control device. In the lockup fastening control device for the automatic transmission according to claim 1.
The lockup control unit calculates the acceleration usable driving force from the difference between the estimated driving force at the time of unlocking based on the unlocking driving force characteristic and the estimated running resistance value based on the traveling resistance characteristic.
The opening margin ratio, which is the ratio of allocating the acceleration usable driving force according to the driver's performance required characteristics and the accelerator opening, is calculated.
A lock-up engagement control device for an automatic transmission, characterized in that the opening allocation driving force is calculated by multiplying the acceleration usable driving force by the opening margin ratio. In the lockup fastening control device for the automatic transmission according to claim 2.
The lock-up control unit has, as the performance required characteristics of the driver, a fuel consumption performance required characteristic that reduces the opening margin ratio as the accelerator opening increases, and increases the opening margin ratio as the accelerator opening increases. An automatic transmission lock-up fastening control device characterized by having driving force performance required characteristics. In the lockup fastening control device for the automatic transmission according to claim 2 or 3.
The lockup control unit calculates the required driving force by converting the opening allocation driving force into the output to the driving wheels.
A lockup engagement control device for an automatic transmission, characterized in that the required torque ratio in the torque converter is calculated by dividing the required driving force by the estimated driving force at the time of lockup based on the lockup driving force characteristic. .. In the lockup fastening control device for the automatic transmission according to claim 4.
The lockup control unit converts the required torque ratio into a required speed ratio using the torque converter performance characteristics.
The target running drive source rotation speed is calculated by dividing the turbine rotation speed by the required speed ratio.
A lockup engagement control device for an automatic transmission, characterized in that slip engagement control of the lockup clutch is executed by feedback control for converging the actual travel drive source rotation speed to the target travel drive source rotation speed.

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