JP2004001761A - Controller for vehicle provided with continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a vehicle provided with a continuously variable transmission capable of properly controlling drive torque while preventing acceleration shock and jerk. <P>SOLUTION: This controller calculates a target drive force on the basis of an output request quantity and vehicle speed, calculates a target output of the power source on the basis of the target drive force, and controls the continuously variable transmission so as to attain the target output. The controller also calculates the target torque of the power source on the basis of the target output and controls the power source so as to attain the target torque. The controller finds a correction target output which changes while being controlled more than the change in the target output in the precess reaching the target drive power, changes relatively greatly at the initial stage of control starting which causes the target drive power to change, and changes relatively less after a prescribed time passes since the start of the control. The controller also controls the change gear ratio of the continuously variable transmission on the basis of the target output, and controls the load of the power source on the basis of the correction target output. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a control device for a vehicle having a continuously variable transmission capable of continuously changing a gear ratio, and more particularly to a control device for controlling a power source and a continuously variable transmission in parallel based on an output request. Things.

Conventionally, a continuously variable transmission (CVT) is known as a vehicle transmission. This continuously variable transmission is essentially a transmission having a function capable of continuously changing the ratio between the input rotation speed and the output rotation speed. An apparatus having a configuration in which the transmission ratio is appropriately set by continuously changing the contact radius position of the transmission member with respect to the rotating member has been put to practical use. Specifically, a belt type continuously variable transmission and a toroidal type continuously variable transmission have been put to practical use.

In the former belt-type continuously variable transmission, each of the input-side pulley and the output-side pulley around which the belt is wound is constituted by a fixed sheave and a movable sheave movable in the axial direction. Is moved in the axial direction to change the groove width of each pulley, thereby continuously changing the winding radius of the belt, that is, the gear ratio. In addition, the tension of the belt is set to the tension corresponding to the required torque by applying an axial force corresponding to the required transmission torque to the movable sheave on the output side pulley. With respect to the movable sheave of the pulley, an output request signal based on the depression amount of the accelerator pedal (accelerator opening), an output request signal from a cruise control that automatically sets the vehicle speed to a predetermined value, and a traveling state such as a vehicle speed. An axial force is applied so as to set a gear ratio determined based on the gear ratio, and the groove width is changed.

According to the continuously variable transmission, the speed ratio can be continuously changed, so that the rotational speed of a power source such as an engine can be changed with a large degree of freedom. Therefore, in vehicles equipped with a continuously variable transmission, not only the gear ratio is controlled to satisfy the required driving torque, but also the gear ratio is controlled for efficient operation of the power source, that is, reduction of fuel consumption. Can be controlled.

An example of the control is described in Japanese Patent Application Laid-Open No. 2000-289496 (the specification of Japanese Patent Application No. 11-29202: Patent Document 1). In the control, first, a target driving force is obtained from the depression amount of the accelerator pedal and the vehicle speed. Next, a target output, a throttle opening, and a target engine speed corresponding to the target driving force are obtained, and a target speed ratio of the continuously variable transmission is obtained based on the target engine speed and the vehicle speed. The engine is controlled so as to generate a target torque determined based on the target output and the engine speed. On the other hand, the continuously variable transmission uses the most efficient engine speed to produce the target output. The gear ratio is controlled so that
Japanese Patent Application Laid-Open No. 2000-289496 (the specification of Japanese Patent Application No. 11-29202)

However, control responsiveness differs between the engine and the continuously variable transmission. That is, the engine can immediately change the torque by increasing the intake air amount and the fuel amount, but the continuously variable transmission changes the gear ratio by gradually increasing or decreasing the groove width of the pulley by hydraulic control. Therefore, it takes time to change to the target gear ratio. However, when the accelerator pedal is depressed, the target driving force changes immediately, and the target output changes. On the other hand, since the engine torque is determined by the calculation of (target output / engine speed), if the engine speed is low due to a delay in shifting of the continuously variable transmission, (target output / engine speed) The engine torque obtained by the calculation in ()) may increase sharply, causing an acceleration shock. Further, a sudden change in torque causes torsional deformation in the power transmission system, which may cause longitudinal vibration (shake) of the vehicle.

In order to eliminate such inconvenience, so-called smoothing control is performed in which even if the target driving force according to the accelerator pedal depression amount is calculated, the target driving value is gradually changed to the target value without immediately changing to the target value. Can be considered. If control is performed based on a corrected target value or a tentatively set target value in such smoothing control, a sudden change in torque is avoided, and no shock occurs. However, the averaging control is, in short, a control in which the corrected target value is reduced to delay the achievement of the final target value with time, so that the control responsiveness deteriorates. Further, if the shift of the continuously variable transmission is controlled based on the target value by the smoothing control, the target value of the shift will gradually change, so that the shift speed of the continuously variable transmission cannot be maximized. As a result, the shift responsiveness, which is originally inferior to the responsiveness, is further deteriorated, and a problem such as an increase in discomfort to the vehicle operation occurs.

On the other hand, even if the control responsiveness of the engine is faster than the shift responsiveness of the continuously variable transmission, the engine itself has an unavoidable response delay, and one example is a delay in the increase in the intake air amount with respect to the increase in the throttle opening. . Furthermore, there is play in the power transmission system based on the clearance between the connecting portions of the members, which may cause a delay in the change of the driving torque.

The present invention has been made in view of the above problems, and provides a control device for a vehicle that can appropriately control the driving force while preventing the occurrence of acceleration shock and longitudinal vibration (shake). It is the purpose.

In order to achieve the above object, a first aspect of the present invention includes a power source and a continuously variable transmission capable of continuously changing a gear ratio, and a target drive based on an output demand and a vehicle speed. Calculating the power, calculating the target output of the power source based on the target driving force, and controlling the continuously variable transmission to achieve the target output, while controlling the target torque of the power source based on the target output. In a control device for a vehicle including a continuously variable transmission that controls the power source so as to achieve the target torque, a change in the target output is suppressed in the process of reaching the target driving force. Target output calculating means for obtaining a corrected target output which changes relatively at the beginning of the control for changing the target driving force and changes relatively small after a lapse of a predetermined time from the start of the control. A control device for controlling a speed ratio of the continuously variable transmission based on the target output, and controlling a load on the power source based on the corrected target output. is there.

According to a second aspect of the present invention, there is provided a power source and a continuously variable transmission capable of continuously changing a speed ratio, and calculates a target driving force based on a required output amount and a vehicle speed. A target output of the power source is calculated based on the driving force, and the continuously variable transmission is controlled to achieve the target output, while a target torque of the power source is calculated based on the target output, and the target torque is calculated. A control device for a vehicle including a continuously variable transmission that controls the power source so as to achieve the target power, in the process of reaching the target driving force, the change being suppressed more than the change in the target output, and At the beginning of the control for changing the driving force, the change is relatively large, the change does not occur for a predetermined time in the middle of the change, and the correction target output that changes relatively small after the predetermined time elapses is corrected. Goal out Calculating means for controlling a speed ratio of the continuously variable transmission based on the target output, and controlling a load of the power source based on the corrected target output. It is a control device.

The corrected target output calculating means according to claim 1 or 2 determines the corrected target driving force with a change gradient changed in the process of reaching the target driving force, as described in claim 3. The modified target output may be determined based on the modified target driving force.

Further, according to a fourth aspect of the present invention, the modified target output calculating means according to any one of the first to third aspects further comprises the step of determining the change gradient of the modified target output by the required acceleration amount or the control parameter obtained from the required acceleration amount. The control device further includes means for calculating the corrected target output by increasing the value of the correction target output.

According to a fifth aspect of the present invention, in the invention of any one of the first to third aspects, the correction target output calculating means obtains the change gradient of the correction target output from the change amount of the required acceleration amount or the required acceleration amount. The control device further comprises means for calculating the corrected target output by increasing the change amount of the control parameter to be increased.

Therefore, according to the first or third aspect of the present invention, in the process of reaching the target driving force, a corrected target output that changes more suppressed than the change in the target output obtained based on the target driving force is obtained. The output changes relatively largely during a predetermined time at the beginning of the control, and then changes relatively small. As a result, the target value of the torque becomes a target value that smoothly changes without overshoot, and can more reliably prevent an acceleration shock. Acceleration control at the time of starting or the like can be performed without causing an abrupt increase in actual torque and without deteriorating fuel efficiency.

According to the second or third aspect of the present invention, in the process of reaching the target driving force, a corrected target output that changes more suppressed than the change in the target output obtained based on the target driving force is obtained. The target output changes relatively largely at the beginning of the control, does not change for a predetermined time, and changes relatively small after the predetermined time has elapsed. As a result, when the power transmission is not completely performed because the backlash of the power transmission system is not blocked, the torque of the power source changes relatively sharply and quick control is performed. After the vehicle is clogged, the change in the torque of the power source is relatively relaxed, so the responsiveness is improved and the elastic torsional deformation that occurs in the power transmission system is suppressed, preventing longitudinal vibration (shake) of the vehicle. it can.

In the invention according to claim 4 or 5, the change gradient of the corrected target output is set so as to compensate for the torque loss corresponding to the inertia torque generated by the rotation change accompanying the acceleration request. This is determined based on the required acceleration or the control parameter based on the required acceleration or the variation thereof.Therefore, there is no fluctuation due to disturbance in the correction of the target torque that compensates for the inertia loss torque. Can be prevented. Further, the gradient of the change is increased as the inertia torque increases. In other words, as the required acceleration and the control parameters based on it or the amount of change thereof increase, the rate of change of the corrected target output increases, so that a delay in rotation change due to inertial force can be prevented, and a shift with good response can be performed. it can.

Next, the present invention will be described based on specific examples shown in the drawings. FIG. 1 is a conceptual diagram of the configuration of a vehicle according to an embodiment of the present invention. The vehicle targeted in this embodiment is a power source (the power source is an internal combustion engine such as a gasoline engine or a diesel engine, or an electric motor such as a motor, or a combination thereof. In the following description, for example, A continuously variable transmission (hereinafter abbreviated as CVT) 12 is arranged between an engine 10) and drive wheels (not shown).

In FIG. 1, a crankshaft 10a of an engine 10 is connected to an input shaft 12a of a belt type CVT 12 via a torque converter 18 having a forward / reverse switching mechanism 14 and a lock-up clutch 16. The output shaft 12b of the CVT 12 is connected to driving wheels of the vehicle via a differential gear device (not shown). When the lock-up clutch 16 is mechanically connected (engaged), the torque of the engine 10 can be transmitted to the drive wheels, and the torque of the drive wheels can be transmitted to the engine 10. When the lock-up clutch 16 is disengaged (disengaged), the engine 10 side and the drive wheel (CVT 12) side become independent (the fluid connection is made by the torque converter 18), and the engine 10 Autonomous driving becomes possible without receiving an unnecessary load on the driving wheel side, and for example, idling rotation can be maintained.

The CVT 12 shown in FIG. 1 changes the groove width of a pair of variable pulleys 20 composed of a movable rotator (movable sheave) 20a and a fixed rotator (fixed sheave) 20b by hydraulic pressure. The speed change ratio is changed by changing the winding radius of the belt 22 so that the tension is maintained constant, and the speed of change of the groove width is the speed of change. Specifically, a hydraulic pressure based on information related to the transmission input torque such as the throttle opening is supplied to an actuator 24 that drives the movable sheave 20a of the output-side variable pulley 20, and the tension of the belt 22 is reduced to the input torque. By setting the tension to an appropriate value and controlling the line pressure supplied to and discharged from the actuator 24 for driving the movable sheave 20a of the variable pulley 20 on the input side in this state, it is possible to arbitrarily control the shift speed. According to the present invention, in addition to the above-mentioned belt-type CVT, a power roller is sandwiched between a pair of disks having a toroidal surface, and the power roller is tilted to change the radius of a contact point with the disk to change the speed. It is also possible to use a toroidal type that performs the following.

The torque converter 18 is basically for continuously operating the engine 10 even when the vehicle is stopped. The forward / reverse switching mechanism 14 is provided because the rotation direction of the engine 10 is limited to one direction and the CVT 12 does not have a reversing operation mechanism, and is a mechanism mainly composed of a planetary gear mechanism. And a mechanism including a reverse gear and a synchronous connection mechanism.

回 転 Rotation speed sensors 26 and 28 are provided to detect the rotation speeds of the input shaft 12a and the output shaft 12b, respectively. These rotation speed sensors 26 and 28 are connected to an electronic control unit (hereinafter, referred to as ECU) 30 mainly composed of a microcomputer, and the ECU 30 is based on detection signals from the rotation speed sensors 26 and 28. Thus, the gear ratio of the CVT 12 is calculated.

Further, an intake pressure sensor 32 for detecting an intake pressure is provided near the intake pipe of the engine 10, and a rotation sensor 34 for detecting the engine speed is provided near the crankshaft 10a. The ECU 30 optimally controls the fuel injection amount and the ignition timing according to the suction pressure detected by the intake pressure sensor 32 and the engine speed detected by the rotation sensor 34.

On the other hand, an accelerator sensor 38 for detecting the accelerator opening is provided near the accelerator pedal 36, and provides the ECU 30 with the detection result. Based on the accelerator opening detected by the accelerator sensor 38, the vehicle speed detected by the rotation speed sensor 28, and the engine rotation speed detected by the rotation speed sensor 34, the ECU 30 controls the suction pressure through the throttle actuator 40 so that, for example, fuel economy is optimized. Control.

The shift lever 42 provided near the driver's seat is provided with a shift sensor 44 for detecting the operation position of the shift lever 42. The ECU 30 provides information such as the drive range detected by the shift sensor 44 and the vehicle speed. The operation of the lock-up clutch 16 and the gear ratio of the CVT 12 are controlled based on information such as the accelerator opening.

Further, a brake pedal sensor 48 for detecting the operation amount and operation speed of the brake pedal 46 is provided near the brake pedal 46. The brake pedal sensor 48 is provided on the brake pedal bracket, and provides the ECU 30 with a voltage proportional to the amount of depression of the brake pedal.

{Circle around (5)} The ECU 30 is connected to an air conditioner (hereinafter referred to as an air conditioner) 50 as an auxiliary device, and controls the drive of the air conditioner. The compressor of the air conditioner 50 is driven by the engine 10.

In this embodiment, in the process of reaching the target driving force calculated by the accelerator opening and the vehicle speed, a target driving force smoothed value in which the driving force is gradually changed is obtained, and based on the target driving force smoothed value. To obtain the target output smoothed value. The shift control of the CVT 12 is performed based on the target output of the engine 10 calculated for the target driving force, and the load control of the engine 10 is performed based on the smoothed target output value.

FIG. 2 is a block diagram illustrating a control process of the first embodiment in the ECU 30. The target driving force calculation means 52 in the ECU 30 obtains the target driving force Ft based on the input accelerator opening Acc and vehicle speed V. Here, the accelerator opening Acc is control data obtained by electrically detecting the depression amount of the accelerator pedal 36 by the accelerator sensor 38, and is used as a request parameter for acceleration or deceleration, that is, a driving force. Therefore, a drive request signal for cruise control for keeping the vehicle speed constant may be used instead of the accelerator opening Acc. The same applies to the input value relating to the vehicle speed. A value related to the vehicle speed V, that is, another input signal having a one-to-one relationship with the vehicle speed V, for example, the rotational speed obtained from the rotating portion is converted into the vehicle speed V and used. You can also. The determination of the target driving force Ft can be derived from a map showing the relationship between the vehicle speed V and the driving force Ft using the accelerator opening Acc as a parameter as shown in FIG. The map is prepared in advance for each vehicle and each engine.

Subsequently, the target output calculating means 54 in the ECU 30 calculates the target output Pt of the engine 10 by integrating the obtained target driving force Ft and the current vehicle speed V. Further, the CVT shift target calculation means 56 in the ECU 30 obtains a target engine speed Net corresponding to the target output Pt in order to control the speed ratio of the CVT 12. Note that the target input shaft speed Nint corresponding to the target output Pt may be obtained. The target engine speed Net or the target input shaft speed Nint can also be derived from a correlation map based on the target output Pt.

Then, the CVT transmission control means 58 in the ECU 30 controls the CVT 12 based on the target engine speed Net and the detected actual engine speed Ne so that the actual engine speed becomes the target engine speed. Control the gear ratio. Specifically, in FIG. 1, the line pressure supplied to and discharged from the actuator 24 that drives the movable sheave 20a of the variable pulley 20 is controlled. That is, the shift control of the CVT 12 is quickly performed so that the target output corresponding to the target driving force that changes when the accelerator pedal 36 is depressed is achieved.

On the other hand, with respect to the target driving force Ft obtained by the target driving force calculation means 52, the target driving force smoothing value calculation means 60 of the ECU 30 sets the target driving force gradually changed in the process of reaching the target driving force Ft. The driving force smoothing value Fs is calculated. The target driving force smoothing value Fs can be calculated by the following 1 / n smoothing formula.
Fs (i) = Ft / n + (n-1) .Fs (i-1) / n

The change in the target driving force smoothing value Fs with respect to the target driving force Ft is, for example, as shown in FIG. The target driving force smoothing value Fs may be derived by preparing such a correlation map in advance. The change in the target driving force smoothing value Fs is not necessarily required to be smooth as shown in FIG. 2, and for example, the increase or decrease amount is limited by a predetermined value in each calculation cycle so as to be stepwise. May be changed.

Subsequently, the target output smoothing value calculation means 62 included in the ECU 30 calculates the target output smoothing value Ps of the engine 10 by integrating the obtained target driving force Ft and the current vehicle speed V. Then, in order to control the engine 10, the engine load calculating means 64 included in the ECU 30 obtains a target engine torque T based on the target output smoothed value Pt and the current engine speed Ne by the following equation. The current input shaft speed Nin may be used instead of the current engine speed Ne.
T = 30Ps / πNe

(4) The engine load control means 66 of the ECU 30 controls the engine 10 so as to attain the calculated target engine torque T. Specifically, the fuel injection amount or the opening of the electronic throttle valve is controlled. At this time, the target engine torque T is calculated using the target output smoothed value Ps obtained by performing the smoothing process on the target driving force Ft. It is possible to prevent a shock from occurring at the time of operation of the vehicle.

As described above, by performing the shift control of the CVT 12 based on the target output and controlling the load of the engine 10 based on the target output smoothed value, the vehicle is controlled in consideration of the difference in responsiveness between the engine 10 and the CVT 12. , The vehicle control without a sense of incongruity, that is, the acceleration response (shift response of the CVT) can be improved while reducing the acceleration shock.

In the specific example described above, the target driving force Ft is corrected by the averaging process to correct the target torque. However, the target output or the target torque is corrected by the averaging process, and the target torque is corrected. Is also good. For example, FIG. 3 shows a modified example of the configuration of FIG. 2, in which the target output smoothing value calculating means 62 calculates the target output smoothing value Ps based on the target output Pt calculated by the target output calculating means 54. , Can be calculated by applying the 1 / n smoothing equation described above, and similar effects can be obtained. Further, in the engine load calculating means 64, a function of performing a smoothing process on the target engine torque T calculated based on the target output Pt can be added, and the same effect can be obtained.

In the specific example described above, the target driving force, the target output, or the target torque is corrected by the averaging process. However, the changing tendency of the corrected target driving force, the corrected target output, or the corrected target torque can be maintained substantially constant. . This is schematically shown in FIG. This control is intended to correct a sudden change in driving force based on the difference between the control response of a power source such as an engine and the shift response of a continuously variable transmission.

Next, considering the delay in the increase in the intake air amount with respect to the increase in the throttle opening and the delay in the change in the drive torque due to the clearance of the connection between the members constituting the power transmission system, etc. An example in which the power source including the engine 10 and the CVT 12 are controlled will be described.

5, a target driving force calculating unit 52 and a target output calculating unit 54, a shift target calculating unit 56 of a continuously variable transmission (CVT), and a CVT transmission control unit (shift control unit) 58 are respectively shown in FIG. Alternatively, it is similar to the example shown in FIG. A modified target driving force calculation means 70 is provided for calculating a corrected target driving force Fta that changes more suppressed than the change in the target driving force Ft calculated by the target driving force calculation means 52. The contents of the control by the corrected target driving force calculating means 70 will be described later.

A means 72 for calculating a target output Pta based on the corrected target driving force Fta calculated by the corrected target driving force calculating means 70 and the vehicle speed V is provided. The corrected target driving force Fta, which is basic data of the calculation performed here, is suppressed and changes with respect to a change in the target driving force Ft corresponding to the accelerator opening Acc, which is an example of the required output amount. Therefore, the calculated value is the corrected target output Pta indicating a suppressed change with respect to the target output Pt obtained by the target output calculating means 54. Equivalent to.

A means 74 for calculating a target torque Ta of the engine 10 based on the corrected target output Pta obtained by the corrected target output calculating means 72 and the engine speed Ne or the input shaft speed Nint. Since the corrected target output Pta, which is the basic data of the calculation performed here, is the corrected target output Pt that changes while being suppressed with respect to the target output Pt calculated by the target output calculating means 54, the value to be calculated is , The corrected target torque Ta, and the calculation means 74 therefore corresponds to the corrected target torque calculation means 74. An instruction signal corresponding to the corrected target torque Ta obtained in this way is input to the engine load control means 66, and the load control of the engine 10 (specifically, throttle opening and fuel supply) is performed so as to achieve the corrected target torque Ta. Quantity, etc.) is controlled. A feedback means 76 for supplying a feedback signal of the engine torque from the engine load control means 66 to the corrected target driving force calculating means 70 is provided.

In the control device according to the present invention having the means shown in FIG. 5, the control shown in FIG. 6 is mainly executed by the corrected target driving force calculating means 70 to calculate the corrected target driving force Fta. The target torque Ta is obtained, and the load control of the engine 10 is executed based on the corrected target torque Ta until the driving force of the vehicle reaches the final target driving force Ft. In FIG. 6, first, a target driving force Ft is calculated (step S301). This is executed by the target driving force calculation means 52, and the target driving force Ft is obtained based on the accelerator opening Acc and the vehicle speed V. Here, the accelerator opening Acc is control data obtained by electrically processing the amount of depression of the accelerator pedal, and is adopted as a control parameter indicating a request for acceleration or deceleration, that is, a request for driving force. Therefore, a drive request signal for cruise control for maintaining the vehicle speed at a predetermined value can be employed as a parameter replacing the accelerator opening Acc. The same applies to the vehicle speed. The rotation speed of another appropriate rotating member having a one-to-one relationship with the vehicle speed V can be adopted as a control parameter instead of a value related to the vehicle speed V such as the vehicle speed V.

Next, it is determined whether or not the amount of change ΔAcc of the accelerator opening Acc per unit time is equal to or greater than a predetermined reference value α (for example, 0.5 deg / 16 ms) (step S302). This corresponds to a process of determining whether or not the vehicle is in a rapid acceleration state in which the required output increases rapidly, and can be performed by comparing the time derivative of the required output signal input to the ECU 30 with a reference value.

(4) If an affirmative determination is made in step S302 because the accelerator pedal is suddenly depressed, the timer Tm is reset to zero and started (step S303). Next, a determination value τ of the time to be counted by the timer Tm, that is, the elapsed time after the accelerator pedal is depressed greatly (step S304). The determination value τ is a value that increases or decreases in accordance with the vehicle speed V or the gear ratio, and a value related to a delay time from when the throttle opening is changed (increased) to when the intake air amount reaches the opening. It is. The determination value τ may be prepared by preparing a map in which the vehicle speed V or the gear ratio is used as a parameter, and reading and using the map. An example of the map is shown in FIG. That is, the determination value τ is set to decrease as the vehicle speed increases or as the gear ratio decreases.

(4) In the subsequent step S305, it is determined whether or not the count value of the timer Tm is equal to or smaller than the determination value τ. That is, it is determined whether or not the elapsed time after the rapid increase in the accelerator opening is determined has not reached the determination value τ. If the determination in step S305 is affirmative, it is immediately after the accelerator pedal is suddenly depressed to increase the throttle opening. For example, the intake air amount has not sufficiently increased, or the throttle opening has not been increased. Is in a state in which the increase in the engine output according to the increase in the engine output has not started reliably. In this case, the first addition amount Fta1 that determines the degree of change (change gradient) of the correction target driving force Fta is adopted (step S306). The addition amount Fta1 is an increase amount of the corrected target driving force Fta for each cycle time at which the control based on the flowchart shown in FIG. 6 is executed, and is calculated in advance as a one-dimensional map using the vehicle speed V shown in FIG. The prepared value is adopted.

On the other hand, when a negative determination is made in step S305, that is, when the count value of the timer Tm exceeds the determination value τ, the intake air amount to the engine 10 starts to increase to an amount corresponding to the throttle opening, Alternatively, the engine output begins to increase to an output corresponding to the throttle opening. Therefore, in this case, the second amount smaller than the above value Fta1 is set as an addition amount for determining the degree of change (change gradient) of the corrected target driving force Fta. Is used (step S307). The addition amount Fta2 is an increase amount of the corrected target driving force Fta for each cycle time at which the control based on the flowchart shown in FIG. 6 is executed, and is calculated as a one-dimensional map using the vehicle speed V shown in FIG. The prepared value is adopted.

Each of these addition amounts Fta1 and Fta2 is set so as to decrease as the vehicle speed increases, and the second addition amount Fta2 of the latter is set to a value smaller than the first addition amount Fta1 of the former. Have been. The addition amounts Fta1 and Fta2 determined in this way are added to the immediately preceding (previous) corrected target driving force Fta, and the corrected target driving force Fta changes so as to gradually increase and continues until the target driving force Ft is reached. (Step S308). That is,
Fta (i) = Fta (i-1) + Fta1 (or Fta2) ≦ Ft
Is continued until the target driving force Ft is reached. In the control example shown in FIG. 6, when the change amount .DELTA.Acc of the accelerator opening is smaller than the reference value .alpha., So that a negative determination is made in step S302, the process proceeds to step S307, in which the corrected target driving force Fta is corrected. The change is controlled to be gentle from the beginning.

(6) Therefore, when the control shown in FIG. 6 is performed, in the process in which the corrected target driving force Fta reaches the target driving force Ft, the changing tendency is bent once and changes more gradually. This is illustrated in FIG. That is, in FIG. 10, when the accelerator pedal is greatly depressed at time t0 and it is determined at time t1 that the amount of change per time is equal to or greater than the reference value, from time t1 to time t2 when the determination value τ elapses. The correction target driving force Fta is set by using a large value Fta1 as the addition amount for each cycle. This is shown by the solid line in FIG. 10 and the target driving force Ft that does not perform such correction or smoothing, that is, the target driving force Ft obtained by the target driving force calculating means 52 (shown by the broken line in FIG. 10). ) Is a target value that makes a change that is suppressed with respect to the change of ()).

After the time point t2 when the judgment value τ has elapsed, a small addition amount Fta2 is adopted as the addition amount of the corrected target driving force Fta, so that the change in the corrected target driving force Fta is further suppressed and becomes gentle. . In other words, after the determination value τ elapses, the change in the corrected target driving force Fta is limited as compared with the change before that.

Since the corrected target output Pta is obtained based on the corrected target driving force Fta in which the change is suppressed as described above, the corrected target output Pta is as shown by a solid line in FIG. This indicates a suppressed change with respect to the target output Pt indicated by the dashed line obtained by the target output calculating means 54 and bends once in the middle of the change, and the change is further restricted after the inflection point. It was done. Further, since the corrected target torque Ta is obtained based on the corrected target output Pta, as shown by the solid line in FIG. 10, there is no excessive overshoot and the target value changes smoothly.

If the determination value τ is set as a value corresponding to the delay of the increase in the intake air amount with respect to the increase in the throttle opening, the peak value of the engine torque is prevented from greatly exceeding the target torque, and the acceleration shock is reduced. It can be reliably prevented. Further, as shown in FIG. 10, the inflection point of the corrected target driving force Fta and the inflection point of the corrected target output and the peak value of the corrected target torque coincide with each other in time and occur at time t2. The control for changing the addition amount of the force Fta from Fta1 to Fta2 may be executed based on the driving force or the output without using the timer Tm.

Therefore, according to the control shown in FIG. 6, it is assumed that each of the correction target values of the driving force and the output is a value that changes relatively largely at the beginning of the control, and that the change is relatively suppressed after a predetermined time has elapsed. Therefore, it is possible to limit the change in the correction target value at the time when the engine output is about to increase after the start of the control due to the delay of the intake of the engine 10 or the response delay of the output. As a result, acceleration control at the time of starting or the like can be performed without causing an excessive response delay of the engine 10, without causing a sudden increase in the actual engine torque, and without deteriorating fuel efficiency.

By the way, in the present invention, in addition to the restriction that the degree of change of each of the correction target values is suppressed in the course of the change, a restriction that does not cause a change temporarily can also be performed. A time chart when such control is performed is shown in FIG. That is, in this control, a value required to eliminate backlash in the power transmission system from the power source to the drive wheels is set in advance as an intermediate value of the target torque as a torque guard value, and the engine torque is set to the torque guard value. Until the guard value is reached, the amount of change in the target driving force, that is, the first addition amount Fta1, is set to a large value. When the engine torque reaches the torque guard value, a torque guard execution flag is set. While the torque guard execution flag is set, the corrected target driving force is kept constant and does not change. Further, the period is controlled by a timer, and when a predetermined time has elapsed, the torque guard execution flag is turned off, and the corrected target driving force Fta is changed again. In this case, since the backlash of the power transmission system is reduced and the output of the power source is transmitted to the power transmission system as it is, the addition amount for changing the corrected target driving force Fta is set to the second value of the small value described above. It is assumed that the addition amount is Fta2.

Therefore, by controlling in this manner, the first addition amount Fat1 can be set to a larger value in a state where the power transmission is not completely performed because the backlash of the power transmission system is not blocked. The change in the engine output or the engine torque becomes relatively sharp, and quick control is performed. After the backlash is reduced, the change in the engine output or the engine torque is relatively reduced. Therefore, the elastic torsional deformation generated in the power transmission system is suppressed while improving the responsiveness, and the longitudinal vibration (shake) of the vehicle is prevented.

Here, the relationship between the above-described specific example or the modified example and the present invention will be described. Functional means for executing the control from step S305 to step S308 shown in FIG. 6, that is, the modified target driving force calculating means 70, and FIG. As shown, the functional means for temporarily maintaining the corrected target driving force Fta at a constant value during the change corresponds to the corrected target output calculating means in the first to third aspects of the present invention.

In the specific example described above, in order to prevent a shock caused by a sudden increase in the target torque, a smoothing process of the target driving force is performed, or an addition value for determining a change gradient of the target driving force or the target output is set to the intake air. This is an example in which the map value is determined in advance in consideration of the delay of the amount and the play of the drive system, but in the present invention, in addition to these, the correction may be made in consideration of the inertia torque. it can.

That is, when the required speed of output (the required amount of acceleration) is increased due to depression of the accelerator pedal and the speed change is performed, the rotational speed of the rotating member constituting the power system including the engine 10 and the CVT 12 changes. Therefore, the inertia torque according to the angular acceleration and the inertia moment acts in a direction to suppress the rotation change. Therefore, in order to compensate for the loss due to the inertia torque and output a torque corresponding to the required acceleration, the degree of suppression of the change in the target torque shown in each of the above-described examples needs to be reduced according to the inertia loss torque. There is. One example is an example in which a correction value ΔF corresponding to the inertia loss torque is added to the 1 / n smoothing value Fs of the target driving force obtained by the target driving force smoothing value calculation means 60 shown in FIG. is there. The correction value ΔF is a value determined in advance based on a control parameter indicating a running state of the vehicle, such as an accelerator opening, which is a required acceleration amount. The value is set to be larger as the required acceleration amount is larger. The correction value ΔF may be increased as the amount of change in the accelerator opening increases.

The change in the target driving force when such a correction value ΔF is added is shown by a broken line in FIG. 2, and the target output smoothing value calculation means 62 is based on the target driving force smoothing value to which the correction value ΔF is added. Is calculated, and the engine load such as the throttle opening is calculated by the engine load calculating means 64 based on the target output. As a result, the calculated target output torque increases by an amount corresponding to the addition of the correction value ΔF. In other words, the degree of suppression of the change in the target output torque is reduced by adding the correction value ΔF, and the correction value ΔF increases as the required acceleration increases or as the change in the required acceleration increases. The degree of suppression of the change in the target output torque decreases as the required acceleration increases or as the change in the required output increases.

If such a correction is made, the obtained target torque is increased by the inertia loss torque accompanying the shift, so that the rotational change can be caused quickly by reducing the influence of the inertial force as much as possible. As a result, the acceleration response is improved. Further, since the correction value ΔF corresponding to the inertia torque used for correcting the target torque does not include a fluctuation factor such as the engine speed and is a predetermined value, the target torque fluctuates due to disturbance, With this, it is possible to reliably prevent the occurrence of sharks.

The correction of the target torque in consideration of the inertia loss torque described above can be performed by correcting the target output or the target torque without correcting the target driving force. That is, in the target output smoothing calculation means 62 shown in FIG. 3, when the target output smoothing process is performed, the target output is set to a predetermined value according to the acceleration request amount such as the accelerator opening or the change amount thereof. What is necessary is just to add so that it may increase according to inertia torque. Further, when performing the smoothing process of the target engine torque T, the engine load calculating means 64 adds a value corresponding to a predetermined inertia torque according to a required acceleration amount such as an accelerator opening or a change amount thereof. Is also good.

Furthermore, the above-described correction of the target torque in consideration of the inertia torque can be incorporated in the control shown in FIG. 6 that takes into account the delay in the increase in the intake air amount and the play in the power transmission system. That is, the map value Fta11 shown in FIG. 12 is adopted as the corrected target driving force addition amount calculated in step S306 in FIG. 6, and the corrected target driving force addition amount calculated in step S307. The map value Fta12 shown in FIG. 13 is adopted instead of the map value shown in FIG. That is, the corrected target driving force addition amounts Fta11 and Fta12 shown in FIGS. 12 and 13 take into account the inertia torque accompanying the rotation change during acceleration, and the lower the vehicle speed, and the accelerator opening degree which is the required acceleration amount. Is set to a larger value as is larger. Note that these values may be set to larger values as the change amount of the accelerator opening is larger.

The engine 10 and the CVT 12 are controlled as shown in FIGS. 5 and 6 except that the target driving force addition amounts Fta11 and Fta12 are set as described above. Therefore, when the target torque is corrected in consideration of the inertia torque, the corrected target driving force, the corrected target output, and the corrected target torque change as indicated by the alternate long and short dash line in FIG. That is, the degree of suppression of the change in the target torque decreases.

Therefore, even in the device which performs such control, the output torque is increased as quickly as possible in a range where the shock does not deteriorate or does not occur, so that the acceleration response is improved. Since no default value is used, sharpness can be prevented. Accordingly, the functional means of steps S306 and S307 configured to calculate the target driving force addition amounts Fta11 and Fta12 shown in FIGS. 12 and 13 and the functional means of step S308 of calculating the corrected target driving force based on the functional means and The functional means of the calculating means 72 of FIG. 5 for calculating the target output based on the corrected target driving force corresponds to the corrected target output calculating means of claim 4 or claim 5.

Note that the target driving force addition amounts Fta11 and Fta12 shown in FIGS. 12 and 13 can also be employed in the control shown in FIG. 11 in which the change of each correction target value is temporarily stopped halfway. Even in such a case, the same operation as in the above-described example occurs. Further, as described above, the target driving force, the target output, and the target torque are calculated based on the required acceleration amount represented by the accelerator opening. Therefore, when the above-described correction considering the inertia torque is performed, the accelerator opening Alternatively, the present invention is not limited to calculating the degree of suppression of the change in the corrected target torque according to the amount of change, but also according to other control parameters such as the target driving force and the target output, or according to the amount of change. The degree of change suppression may be calculated.

1 is a configuration conceptual diagram illustrating a schematic configuration of a vehicle including a control device according to an embodiment of the present invention. It is a block diagram explaining a processing procedure in a control device concerning an embodiment of the present invention. FIG. 9 is a block diagram illustrating another processing procedure in the control device according to the embodiment of the present invention. 5 is a time chart showing changes in a target driving force and a target output, a power source rotation speed, and a target torque according to the embodiment of the present invention. FIG. 6 is a block diagram for explaining a control system according to another specific example of the present invention. 6 is a flowchart for explaining a control example executed in the specific example shown in FIG. 5. It is a figure showing an example of a map of the judgment value of the time to count in the control example. FIG. 9 is a diagram conceptually illustrating an example of a map of a first addition amount for calculating a corrected target driving force in the control example. It is a figure which shows notionally the example of the map of the 2nd addition amount for calculating the correction | amendment target drive force in the example of a control. 7 is a time chart showing changes in a corrected target driving force, a corrected target output, a power source rotation speed, and a corrected target torque when the control shown in FIG. 6 is performed. 6 is a time chart showing changes in a corrected target driving force, a corrected target output, a power source rotation speed, and a corrected target torque when a control for temporarily prohibiting a change in the corrected target driving force is performed during the change. FIG. 6 is a diagram conceptually illustrating an example of a map of a first addition amount considering an inertia torque for calculating a corrected target driving force used in a control example executed by the control system illustrated in FIG. 5. FIG. 6 is a diagram conceptually illustrating an example of a map of a second addition amount considering an inertia torque for calculating a corrected target driving force used in a control example executed by the control system illustrated in FIG. 5.

Explanation of reference numerals

10: engine, # 12: continuously variable transmission (CVT), # 16: lock-up clutch, # 18: torque converter, # 30: electronic control unit (ECU), # 36: accelerator pedal, # 52: target driving force calculation means, # 54: target Output calculation means, # 56 CVT shift target calculation means, # 58 CVT transmission control means, # 64 Engine load calculation means, # 66 Engine load control means, # 70 Modified target driving force calculation means, # 72 Modified target output calculation means , # 74: corrected target torque calculating means, # 76: feedback means.

Claims (5)

A power source and a continuously variable transmission capable of continuously changing a gear ratio, calculating a target driving force based on an output demand and a vehicle speed, and calculating a target power source based on the target driving force. Calculating the output, controlling the continuously variable transmission to achieve the target output, calculating the target torque of the power source based on the target output, and controlling the power source to achieve the target torque. In a vehicle control device having a continuously variable transmission to be controlled,
In the process of arriving at the target driving force, the target output changes and is suppressed more than the change of the target output. A corrected target output calculating means for obtaining a corrected target output that changes relatively small after the lapse of time,
A continuously variable transmission, wherein the transmission ratio is controlled based on the target output, and the load of the power source is controlled based on the corrected target output. Control device for vehicle equipped with. A power source and a continuously variable transmission capable of continuously changing a gear ratio, calculating a target driving force based on an output demand and a vehicle speed, and calculating a target power source based on the target driving force. Calculating the output, controlling the continuously variable transmission to achieve the target output, calculating the target torque of the power source based on the target output, and controlling the power source to achieve the target torque. In a vehicle control device having a continuously variable transmission to be controlled,
In the process of reaching the target driving force, the target output changes more suppressed than the change in the target output, and at the beginning of the control for changing the target driving force, changes relatively large, and a predetermined time during the change. And a corrected target output calculating means for obtaining a corrected target output that changes relatively small after the lapse of the predetermined time.
A continuously variable transmission, wherein the transmission ratio is controlled based on the target output, and the load of the power source is controlled based on the corrected target output. Control device for vehicle equipped with. The modified target output calculating means is configured to determine a modified target driving force with a changed gradient in a process of reaching the target driving force, and to determine the modified target output based on the modified target driving force. A control device for a vehicle provided with the continuously variable transmission according to claim 1 or 2. The correction target output calculation means includes a means for calculating the correction target output by increasing the change gradient of the correction target output as the required acceleration or the control parameter obtained from the required acceleration increases. A control device for a vehicle, comprising the continuously variable transmission according to any one of claims 1 to 3. The correction target output calculating means calculates the correction target output by increasing the change gradient of the correction target output as the change amount of the required acceleration amount or the change amount of the control parameter obtained from the required acceleration amount increases. A control device for a vehicle provided with the continuously variable transmission according to any one of claims 1 to 3, comprising:

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