JP2005127424A - Driving force control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve sufficient speed reduction when a driver needs to reduce vehicle speed. <P>SOLUTION: A gear ratio command value calculation part 610 calculates a gear ratio command value tRATIO before correction of a continuously variable transmission by map on the basis of a vehicle speed aVSP and a drive torque command value cTDR. A gear ratio command value calculation part 630 after correction calculates a gear ratio command value cRATIO after the correction of the continuously variable transmission on the basis of a vehicle travelling condition, for example, vehicle speed aVSP, of the gear ratio command value tRATIO before the correction, and of a road gradient estimated value by a road gradient estimating part 640. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a driving force control apparatus for a vehicle.

  As a conventional vehicle driving force control device, for example, there is one described in Patent Document 1. In Patent Document 1, a target acceleration or target deceleration is obtained from the accelerator opening, and the valve opening of the throttle valve is controlled so that the target acceleration / deceleration can be achieved. Next, the actual vehicle speed is detected by the vehicle speed sensor, and the actual acceleration / deceleration is obtained by differentiating the vehicle speed. It is determined whether or not the target acceleration / deceleration matches the actual acceleration / deceleration. If they do not match, the valve opening is corrected.

Further, in Patent Document 2, when a negative driving force (a state where the engine is driven from a vehicle) is required, the engine torque command value and the gear ratio command value are set to engine brake characteristics (throttle opening fully closed and fuel cut). (State) and the output command value. This makes it possible to cope with negative driving force.
Furthermore, in a continuously variable transmission, the gear ratio is determined based on a map prepared in advance from the vehicle speed and the accelerator opening (drive torque), and when the accelerator is depressed, the gear ratio is reduced, that is, the continuously variable transmission is moved to the high gear side. On the other hand, when the accelerator is released, it is known to increase the gear ratio, that is, to shift the continuously variable transmission to the low gear side.

Further, Non-Patent Document 1 discloses an optimum fuel efficiency from a combination of an engine torque and a gear ratio that realizes a driving force necessary to realize a driving force necessary to maintain a vehicle speed command value in a vehicle with continuously variable transmission. Are calculated and combinations are controlled (considering only steady state). Specifically, the horsepower command value is calculated from the driving force command value and the vehicle speed, and the optimal fuel consumption driving line (a line defined by the relationship between the engine torque and the engine speed) calculated in advance and the equal horsepower line are calculated. The intersection is calculated.
JP 2000-205015 A Japanese Patent Laid-Open No. 11-78594 Eiyuki Morita, “DBW Control Algorithm”, Journal of the Society of Automotive Engineers, 1994, vol. 48, no. 10, p13-19

Here, when the driver needs to decelerate the vehicle, for example, when the vehicle travels downhill, it calculates the negative driving force and the gear ratio, which are the driving torque necessary for deceleration, and is optimal for realizing this. Driving with good fuel efficiency.
However, when the driver releases the accelerator, the target acceleration turns to the deceleration side, so the throttle is controlled to the closed side. If the deceleration is not enough when the throttle is fully closed on a downhill, etc., the continuously variable transmission is controlled to the downshift side (low gear side) to compensate for it. If the downshift response of the vehicle is poor, the deceleration will be delayed, causing the driver to feel unsatisfactory.

Further, when there is a preceding vehicle, there is a problem that the driver is more decelerated when the distance between the vehicle and the relative speed with the preceding vehicle changes in the approaching direction.
The present invention has been made paying attention to such a problem, and an object thereof is to ensure sufficient deceleration when the driver needs to decelerate the vehicle.

  Therefore, the present invention sets the target drive torque based on the driving state of the vehicle, sets the target speed ratio of the transmission based on the target drive torque, and sets the target engine torque based on the target drive torque and the actual speed ratio. A driving force control apparatus for a vehicle that sets, controls a transmission based on a target gear ratio, and controls the engine based on a target engine torque, and corrects the target gear ratio in accordance with a traveling state of the vehicle.

  According to the present invention, since the target gear ratio is corrected in accordance with the traveling state of the vehicle, for example, when the driver releases the accelerator while the vehicle is traveling on a downhill, the response of the transmission is affected. It is possible to give the driver a sufficient feeling of deceleration without being lost. Further, since the driving torque does not change even if the speed ratio is changed, there is an effect that it is possible to prevent the driver from feeling uncomfortable due to the change of the speed ratio.

The present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a configuration according to an embodiment of the present invention.
The engine 1 is provided with an engine speed sensor 2 and a throttle actuator (hereinafter referred to as “throttle ACTR”) 3. The engine speed sensor 2 outputs an output corresponding to the actual speed aNE of the engine 1. The throttle ACTR3 can adjust the engine torque by adjusting the opening of the throttle valve 3a.

The engine 1 and the continuously variable transmission (CVT) 4 are connected via a torque converter 5. Torque generated in the engine 1 is transmitted to the continuously variable transmission 4 via the torque converter 5. The continuously variable transmission 4 can change the gear ratio, and torque is transmitted through the belt 4a.
The final gear 6 includes a gear 8 provided on a shaft 7 connected to the continuously variable transmission 4 and a gear 11 provided on an axle 10 including a tire 9. Therefore, torque generated in the engine 1 is transmitted to the axle 10 via the torque converter 5, continuously variable transmission 4, and final gear 6.

  Further, as shown in the figure, an engine speed sensor 2 disposed in the engine 1, an accelerator opening sensor 13 for detecting the depression amount APO of the accelerator pedal 12, a vehicle speed sensor 14 disposed in the gear 11 of the axle 10, and control start Outputs from various sensors such as a switch (hereinafter referred to as “control start SW”) 15, a brake switch (hereinafter referred to as “brake SW”) 16 and an inter-vehicle distance sensor 17 (rotation speed aNE, accelerator depression amount APO, vehicle speed aVSP, A control SW 15, a brake SW ON / OFF signal, and an inter-vehicle distance dist) are input to an electronic control device for vehicle speed control (hereinafter referred to as “vehicle speed control ECU”) 100. The control start SW 15 is various switches such as an auto cruise switch.

  The vehicle speed control ECU 100 performs processing to be described later, and controls each command value to an electronic control device for engine control (hereinafter referred to as “engine ECU”) 20 and an electronic control device for transmission control (hereinafter referred to as “transmission ECU”) 30. Is output. The engine ECU 20 outputs a throttle opening signal of the engine 1 to control the throttle ACTR3 and the like. The transmission ECU 30 outputs a gear ratio change signal to the continuously variable transmission 4 to change the gear ratio.

Next, these control configurations will be described with reference to FIG.
The inter-vehicle distance sensor 17 uses, for example, a laser radar or the like, and detects the relative speed dVSP from the inter-vehicle distance dist with respect to the preceding vehicle and the temporal change in the inter-vehicle distance by reflected waves of light or radio waves.
The control start SW 15 detects whether or not to execute vehicle speed control. When the SW is on, it is determined that the vehicle speed control is being executed. On the other hand, when the SW is off, the vehicle speed control is stopped.

The brake SW 16 detects whether or not the driver is stepping on the brake. When the brake is depressed, it is turned on. On the other hand, when the brake is released, the vehicle is turned off.
The accelerator opening sensor 13 detects the depression amount APO of the accelerator pedal 12 by the driver.

The vehicle speed sensor 14 detects the actual vehicle speed aVSP of the vehicle from the number of rotations of the gear 11 provided on the axle 10 including the tire 9.
The engine speed sensor 5 detects the actual engine speed aNE from the ignition signal of the engine 1. For example, a crank angle sensor is used as the engine rotation sensor 5.
The vehicle speed control ECU 100 includes a microcomputer and its peripheral components, and reads signals from the control start SW 15, brake SW 16, accelerator opening sensor 13, vehicle speed sensor 14, and engine speed sensor 2 every control cycle (for example, 10 ms). The calculation process is performed at, and command values are output to the engine ECU 20 and the transmission ECU 30.

The vehicle speed control ECU 100 controls the vehicle speed by using a throttle and a transmission.
Engine ECU 20 calculates a throttle opening based on engine torque command value cTE output from vehicle speed control ECU 100, and outputs a throttle opening signal to throttle ACTR3. The throttle ACTR3 adjusts the opening of the throttle valve 3a of the engine 1 according to the throttle opening signal.

The transmission ECU 30 changes the speed ratio of the transmission 4 based on the speed ratio command value (target speed ratio) cRATIO output from the vehicle speed control ECU 100.
Here, the vehicle speed control ECU 100 includes a control start determination unit 200, a target vehicle speed calculation unit 300, a vehicle speed control unit 400, an actual gear ratio calculation unit 500, and a driving force distribution unit 600 that are configured in the form of microcomputer software as shown in the figure. It has.

The control start determination unit 200 determines the presence / absence of the flag fSTART based on signals from the control start SW 15 and the brake SW 16, and outputs this to the engine ECU 20, the transmission ECU 30 and the target vehicle speed calculation unit 300.
When there is an execution command (fSTART = 1) for the control execution flag fSTART, the target vehicle speed calculation unit 300 sets the target vehicle speed tVSP based on the accelerator depression amount APO of the accelerator opening sensor 13 and the vehicle speed aVSP of the vehicle speed sensor 14. Is output to the vehicle speed control unit 400. The target vehicle speed calculation unit 300 includes means for estimating the curvature (curvature radius) of a curved road, which will be described later. When the vehicle travels on a curved road, the acceleration (deceleration) is operated by operating the accelerator pedal 12. By correcting, the vehicle speed can be reduced.

The vehicle speed control unit 400 calculates a drive torque command value (target drive torque) cTDR based on the target vehicle speed tVSP and the vehicle speed aVSP, and outputs this to the driving force distribution unit 600.
The actual gear ratio calculation unit 500 calculates the actual gear ratio aRATIO based on the vehicle speed aVSP and the engine speed aNE, and outputs this to the driving force distribution unit 600.
The driving force distribution unit 600 calculates the engine torque command value cTE and the gear ratio command value cRATIO based on the driving torque command value cTDR, the vehicle speed aVSP, the actual gear ratio aRATIO, and the inter-vehicle distance dist, and uses the engine torque command value cTE as the engine ECU 20. The gear ratio command value cRATIO is output to the transmission ECU 30. Thus, when the vehicle travels on a curved road, the transmission ratio of the continuously variable transmission 4 and the throttle opening are appropriately distributed while maintaining the driving torque.

Next, the operation (processing) of the control start determination unit 200 will be described based on the flowchart of FIG. This flowchart is executed every predetermined time (for example, 10 ms).
In step 1 (shown as “S1” in the figure, the same applies hereinafter), a signal from the control start SW 15 is read to determine whether or not the SW is in an ON state. If the SW is on (Yes), the process proceeds to step 2. On the other hand, if the SW is in the off state (No), the process proceeds to step 4 described later.

In step 2, a signal from the brake SW 16 is read to determine whether the SW is in an off state. When it is in the off state (Yes), the process proceeds to Step 3. On the other hand, if it is in the on state (No), the process proceeds to step 4 described later.
In step 3, the control execution flag fSTART is set to 1, and the process is terminated. This executes speed control.

  In step 4, the control execution flag fSTART is set to 0, and the process ends. That is, when the control SW1 is in the off state or the brake SW16 is in the on state, the vehicle speed control is stopped. When the driver is stepping on the brake, since the actual vehicle speed aVSP cannot be made to follow the target vehicle speed tVSP with the throttle opening and the gear ratio, the flag is set to 0 and the control is stopped.

Here, the control execution flag fSTART is output from the vehicle speed control ECU 100 to the engine ECU 20 and the transmission ECU 30, and the engine ECU 20 and the transmission ECU 30 are controlled as follows according to the flag.
When the control flag fSTART is 1, the engine ECU 20 determines that the vehicle speed control is being executed, and throttles ACTR3 so as to output engine torque based on the engine torque command value cTE output from the vehicle speed control ECU 100 (control start determination unit 200). To control. On the other hand, when the control execution flag fSTART is 0, the engine ECU 20 determines that the vehicle speed control is stopped, and controls the throttle ACTR3 so as to output the engine torque according to the accelerator depression amount APO.

  Similarly, when the control execution flag fSTART is 1, the transmission ECU 30 determines that the vehicle speed control is being executed, and sets the gear ratio in the gear ratio command value cRATIO output from the vehicle speed control ECU 100. On the other hand, when the control execution flag fSTART is 0, the transmission ECU 30 determines that the vehicle speed control is stopped, and sets a gear ratio according to the accelerator depression amount APO and the actual vehicle speed aVSP.

Next, the configuration of the target vehicle speed calculation unit 300 will be described with reference to FIG.
The target vehicle speed calculation unit 300 includes a target acceleration determination unit 310 and an integration processing unit 320, reads the control execution flag fSTART, the actual vehicle speed aVSP, and the accelerator depression amount APO, and calculates the target vehicle speed tVSP based on these.
The target acceleration determining unit 310 determines the target acceleration tACC based on the map shown in FIG. 5 from the accelerator depression amount APO and the target vehicle speed tVSP previous value calculated by the integration processing unit 330. As shown in FIG. 5, the target acceleration tACC increases as the accelerator depression amount APO increases. Further, in order to cope with the fact that the driving resistance increases and the realizable acceleration decreases as the vehicle speed increases, in FIG. 5, the target acceleration tACC is set to decrease as the vehicle speed increases for the same accelerator depression amount APO. Has been.

The integration processing unit 320 calculates the target vehicle speed tVSP based on the control execution flag fSTART, the actual vehicle speed aVSP, and the target acceleration tACC.
FIG. 6 is a flowchart showing the processing contents of the integration processing unit 320.
In step 11, it is determined whether or not the control execution flag fSTART is 1. If the control execution flag fSTART is 1, that is, if the control start SW 15 is on and the brake SW 16 is off, the process proceeds to step 12. On the other hand, if the control execution flag fSTART is 0, that is, if the control start SW 15 is off or the brake SW 16 is on, the process proceeds to step 13.

In step 12, the target vehicle speed tVSP (= tVSP previous value + tACC) is calculated by adding the target acceleration tACC to the previous tVSP value, and the previous tVSP value is updated with the target vehicle speed tVSP (tVSP previous value = tVSP). The target vehicle speed tVSP calculated here is output to the vehicle speed control unit 400, while the previous value of tVSP is output to the target acceleration determination unit 310.
In step 13, the target vehicle speed tVSP and the previous value of tVSP are initialized with the actual vehicle speed aVSP (tVSP = aVSP, tVSP previous value = aVSP).

Next, the configuration of the vehicle speed control unit 400 will be described with reference to FIG.
The vehicle speed controller 400 includes a phase compensator 410, a reference model 420, a feedback compensator 430, and a drive torque converter 440. A feedforward control unit (hereinafter referred to as “F / F control unit”) configured by the phase compensator 41 and a feedback control unit (hereinafter referred to as “F / B control” configured by the reference model 420 and the feedback compensator 430). A two-degree-of-freedom control system.

The vehicle speed control unit 400 is controlled by the F / F control unit and the F / B control unit so that the transfer characteristic when the target vehicle speed tVSP is input and the own vehicle speed aVSP is output becomes the transfer characteristic of the reference model 420 of FIG. I do. The transfer function G _T (s) of the reference model 420 is expressed by the following equation.

すなわち、規範モデル４２０の伝達特性Ｇ_T（ｓ）は時定数τ_Hの１次のローパスフィルタと無駄時間Ｌ_Vとからなる。ここでｓはラプラス演算子を表す。
制御対処の車両モデルは、駆動トルク指令値ｃＴＤＲを操作量とし、車速ａＶＳＰを制御量としてモデル化することによって、車両のパワートレインの挙動は図８に示す簡易非線形モデルにて、次式で表される。

That is, the transfer characteristic G _T (s) of the reference model 420 includes a first-order low-pass filter having a time constant τ _H and a dead time L _V. Here, s represents a Laplace operator.
The vehicle model for control is modeled using the drive torque command value cTDR as the operation amount and the vehicle speed aVSP as the control amount, so that the behavior of the vehicle's powertrain is expressed by the following equation using the simple nonlinear model shown in FIG. Is done.

ここで、Ｍは車両質量、Ｒｔはタイヤ動半径、Ｌ_Pは無駄時間を表す。駆動トルク指令値を入力とし、車速を出力とする車両モデルは積分特性となる。但し、制御対象の特性にはパワートレイン系の遅れにより無駄時間も含まれることになり、使用するアクチュエータやエンジン１によって無駄時間Ｌ_Pは変化する。

Here, M represents the vehicle mass, Rt represents the tire moving radius, and L _P represents the dead time. A vehicle model having the drive torque command value as input and the vehicle speed as output has integral characteristics. However, the characteristics to be controlled include a dead time due to the delay of the power train system, and the dead time L _P varies depending on the actuator and the engine 1 to be used.

Referring to FIG. 7 again, the F / F control unit (phase compensator 410) determines the responsiveness of the control target when the target vehicle speed tVSP is input and the actual vehicle speed aVSP is output as a predetermined primary delay and waste. The F / F command value is calculated by matching with the characteristic of a predetermined transfer characteristic G _T (s) having a time element. If the dead time of the controlled object is ignored and the transfer characteristic G _T (s) of the reference model 420 is a characteristic in the first-order low-pass filter having the time constant τ _H , the following expression is obtained.

Ｆ／Ｂ制御部では、規範モデル４２０により、目標車速ｔＶＳＰを入力した場合の伝達関数Ｇ_T（ｓ）により規範応答Ｖ_refを算出する。この規範応答Ｖ_refと自車速ａＶＳＰとの差をフィードバック補償器４３０の入力とする。フィードバック補償器４３０は、乗算（比例ゲインＫ_p）及び積分（積分ゲインＫ_i）によりＦ／Ｂ指令値を算出する。

In the F / B control unit, the normative response V _ref is calculated from the normative model 420 based on the transfer function G _T (s) when the target vehicle speed tVSP is input. The difference between the reference response V _ref and the host vehicle speed aVSP is used as an input to the feedback compensator 430. The feedback compensator 430 calculates the F / B command value by multiplication (proportional gain K _p ) and integration (integration gain K _i ).

Then, an addition value of the F / F command value and the F / B command value is input to the drive torque conversion unit 440. The F / B command value suppresses the influence of disturbances and modeling errors. An example of the feedback compensator 430 is a PI compensator including a proportional gain K _p and an integral gain K _i .
The drive torque converter 440 receives the value obtained by adding the F / B command value calculated by the F / B compensator 430 to the F / F command value calculated by the phase compensator (F / F controller) 410. The vehicle mass M and the tire dynamic radius Rt are multiplied to calculate the drive torque command value cTDR.

  Next, the actual speed ratio calculation unit 500 in FIG. 2 calculates the actual speed ratio aRATIO from the own vehicle speed aVSP and the engine speed aNE according to the following equation.

なお、Ｇｆはファイナルギア比である。
次に駆動力分配部６００の構成について図９に基づいて説明する。
駆動力分配部６００は、変速比指令値算出部６１０、エンジントルク指令値算出部６２０、補正後変速比指令値算出部６３０、路面勾配推定部６４０及び道路曲率推定部６５０から構成されており、車間距離ｄｉｓｔ、相対速ｄＶＳＰ、車速ａＶＳＰ、駆動トルク指令値ｃＴＤＲ及び実変速比ａＲＡＴＩＯに基づいて変速比指令値ｃＲＡＴＩＯ及びエンジントルク指令値ｃＴＥを算出する。

Gf is the final gear ratio.
Next, the configuration of the driving force distribution unit 600 will be described with reference to FIG.
The driving force distribution unit 600 includes a gear ratio command value calculation unit 610, an engine torque command value calculation unit 620, a corrected gear ratio command value calculation unit 630, a road surface gradient estimation unit 640, and a road curvature estimation unit 650. A gear ratio command value cRATIO and an engine torque command value cTE are calculated based on the inter-vehicle distance dist, the relative speed dVSP, the vehicle speed aVSP, the drive torque command value cTDR, and the actual gear ratio aRATIO.

  The gear ratio command value calculation unit 610 calculates a gear ratio command value tRATIO before correction based on the input vehicle speed aVSP and the drive torque command value cTDR. The speed ratio command value tRATIO before correction is calculated from the drive torque command value cTDR and the host vehicle speed aVSP using the map shown in FIG. FIG. 10 is a map when the continuously variable transmission 4 is used. The horizontal axis indicates the vehicle speed (km / h), and the vertical axis indicates the gear ratio. In this map, the vehicle speed and the gear ratio increase as the driving torque increases, and the gear ratio decreases as the vehicle speed increases when the driving torque is a predetermined value.

  Based on the input drive torque command value cTDR and actual gear ratio aRATIO, engine torque command value calculation unit 620 calculates engine torque command value cTE by the following equation.

路面勾配推定部６４０は、現在走行中の路面勾配および自車前方の路面勾配を推定し、この値を変速比指令値補正部６３０に出力する。
ここで路面勾配の算出には、先ず理想車両駆動トルクを、駆動系入力トルクに駆動系の変速比を乗じることで算出する。駆動系損失トルクを、変速機４の油圧、油温、入力軸回転数、変速比のうち少なくとも一つに基づき算出する。理想車両駆動トルクから駆動系損失トルクを減じて有効車両駆動トルクを算出する。次に、平坦路走行抵抗トルクを車速に基づき算出し、加速抵抗トルクを車両の加速度に基づき算出する。勾配抵抗トルクを、有効車両駆動トルクから平坦路走行抵抗トルクと加速抵抗トルクとを減じて算出する。走行中の路面勾配は、勾配抵抗トルクから算出する。そして、有効車両駆動トルクから、平坦路走行抵抗トルク、旋回抵抗トルク及び加速抵抗トルクを減じて路面勾配トルクを算出する。そして、この路面勾配トルクを基に路面勾配を算出する。

The road surface gradient estimation unit 640 estimates the road surface gradient currently being traveled and the road surface gradient ahead of the host vehicle, and outputs this value to the gear ratio command value correction unit 630.
Here, the road surface gradient is calculated by first calculating the ideal vehicle drive torque by multiplying the drive system input torque by the speed ratio of the drive system. The drive system loss torque is calculated based on at least one of the hydraulic pressure of the transmission 4, the oil temperature, the input shaft rotation speed, and the gear ratio. The effective vehicle drive torque is calculated by subtracting the drive system loss torque from the ideal vehicle drive torque. Next, the flat road running resistance torque is calculated based on the vehicle speed, and the acceleration resistance torque is calculated based on the acceleration of the vehicle. The gradient resistance torque is calculated by subtracting the flat road running resistance torque and the acceleration resistance torque from the effective vehicle driving torque. The road gradient during traveling is calculated from the gradient resistance torque. Then, the road surface gradient torque is calculated by subtracting the flat road running resistance torque, the turning resistance torque, and the acceleration resistance torque from the effective vehicle driving torque. Then, the road surface gradient is calculated based on this road surface gradient torque.

For estimation of the road surface gradient, a method of calculating the gradient estimated value from the deviation between the acceleration command value and the actual acceleration (accelerated estimated value or detected acceleration value) may be used. Further, the road surface gradient may be obtained from position information from a sensor for detecting the gradient or a navigation system.
The road curvature estimation unit 650 estimates the road road curvature ahead of the host vehicle and outputs this value to the corrected gear ratio command value calculation unit 630.

  Here, the road curvature is estimated by measuring the lateral displacement of the vehicle with respect to the road, the steering angles of the front and rear wheels of the vehicle, and the vehicle speed aVSP of the vehicle, and based on these measured values, the road curvature is calculated by the road curvature calculator. Calculated by state estimation in modern control theory. The lateral displacement of the vehicle is measured from the front gazing point by capturing an image ahead of the vehicle with a CCD camera, sending it to the image processing device. The steering angles of the front and rear wheels of the vehicle are measured based on the outputs of the front wheel steering angle sensor and the rear wheel steering angle sensor. The vehicle speed aVSP is measured by the vehicle speed sensor 14.

As for road curvature estimation, a method of detecting a lane marker or a preceding vehicle in the vicinity of the host vehicle with an in-vehicle camera or the like and estimating the road curvature by image processing or the like may be used. Moreover, you may use the method calculated | required from the positional information from a navigation system.
The corrected gear ratio command value calculation unit 630 calculates the corrected gear ratio command value cRATIO based on the curvature estimation value, the gradient estimated value, the inter-vehicle distance dist, the relative speed dVSP, the vehicle speed aVSP, and the uncorrected gear ratio command value tRATIO. Is calculated.

  The corrected gear ratio command value cRATIO calculated in this way is output to the transmission ECU 30 as shown in FIG. Engine torque command value cTE is output to engine ECU 20. Thus, the gear ratio and the throttle opening can be changed while maintaining the torque, and sufficient deceleration can be achieved when the driver releases the accelerator pedal while the vehicle is traveling on a curved road.

A process in which engine ECU 20 calculates a throttle opening command value (signal) for throttle ACTR3 will be described with reference to FIG.
As illustrated, the engine torque command value cTE and the engine speed aNE are input to the engine throttle opening command value calculation unit 700. Then, these are applied to the overall engine performance map to calculate the throttle opening command value.

  The overall engine performance map indicates that the throttle opening is increased in order to increase the engine torque when the engine speed aNE increases. This is because the engine speed aNE increases when the continuously variable transmission 4 is shifted to the downshift side (low gear side) based on the corrected gear ratio command value cRATIO calculated by the corrected gear ratio command value calculation unit 630. This is because the engine torque decreases, but the throttle opening is increased to keep the torque constant in order to prevent this torque reduction.

Here, for example, processing performed by the corrected gear ratio command value calculation unit 630 when the vehicle enters a downhill will be described with reference to FIG.
FIG. 12 is a table for calculating the gear ratio correction value α of the continuously variable transmission 4, where the horizontal axis indicates the road surface gradient (%) and the vertical axis indicates the gear ratio correction value α. In addition, it has shown that the gradient of a descending board road is so steep that the road surface gradient is negative (left side of a figure).

  The corrected gear ratio command value calculation unit 630 multiplies the gear ratio correction command value tRATIO calculated by the gear ratio command value calculation unit 610 by the gear ratio correction value α to correct the corrected gear ratio command value cRATIO (= tRATIO). X α) is calculated. Here, when the road surface is a flat road or a climbing road, the gear ratio correction value α = 1, and when the road surface is a descending road, the gear ratio correction value α is gradually increased according to the gradient. In other words, the corrected gear ratio command value cRATIO is corrected to increase, that is, the continuously variable transmission 4 is corrected to the low gear side, as the road gradient on which the vehicle travels becomes a steep downhill.

Even with the same road surface gradient, the higher the vehicle speed, the less influence (acceleration is difficult) on the acceleration caused by the downward gradient due to running resistance, etc., so that the appropriate amount of deceleration can be obtained by reducing the correction amount as the vehicle speed increases. .
FIG. 13 shows changes in parameters in the conventional example, the present invention, and the apparatus. (A) shows a conventional example, and (B) shows an example of the present application. The horizontal axis represents time, and the vertical axis represents road surface gradient, vehicle speed, accelerator opening, drive torque command value, throttle opening, and gear ratio (the dotted line is the gear ratio command value and the solid line is the actual gear ratio).

  As illustrated, in the embodiment of the present application, when the vehicle enters a downhill, the gear ratio correction value α is increased, and the gear ratio of the continuously variable transmission 4 is set to the upshift side, that is, the transmission 4 is set to the low gear side. . As a result, when the driver feels that the vehicle needs to be decelerated and releases the accelerator pedal, the continuously variable transmission 4 has already shifted to the downshift side (low gear side). A feeling of insufficient deceleration due to a response delay of the transmission 4 can be prevented.

Further, since the driving force distribution unit 600 calculates the engine torque command value cTE by feeding back the gear ratio, the driving torque does not change even if the gear ratio is corrected. The driver will not feel discomfort due to the side (low gear side).
Next, processing performed by the corrected gear ratio command value calculation unit 630 when there is a preceding vehicle ahead of the host vehicle will be described with reference to FIGS. 14 and 15.

FIG. 14 is a table for calculating the gear ratio correction value β of the continuously variable transmission 4 using the inter-vehicle distance dist between the host vehicle and the preceding vehicle, the horizontal axis is the inter-vehicle distance (m), and the vertical axis is the gear ratio correction. The value β is shown.
The corrected gear ratio command value calculation unit 630 multiplies the pre-speed ratio correction command value tRATIO calculated by the gear ratio command value calculation unit 610 by the gear ratio correction value β to correct the corrected gear ratio command value cRATIO (= tRATIO). Xβ) is calculated.

Here, when the inter-vehicle distance dist with the preceding vehicle is long (the preceding vehicle is away), the gear ratio correction value β = 1, and the gear ratio correction value β is gradually increased as the inter-vehicle distance dist becomes shorter. That is, as the inter-vehicle distance dist becomes shorter, the corrected gear ratio command value cRATIO is corrected to the increase side, that is, the transmission 4 is corrected to the downshift side (low gear side).
FIG. 15 is a table for calculating the gear ratio correction value γ of the continuously variable transmission 4 using the relative speed dVSP between the host vehicle and the preceding vehicle. The horizontal axis is the relative speed (km / h), and the vertical axis is the speed change. The ratio correction value γ is shown. In addition, it has shown that it is approaching the preceding vehicle, so that relative speed is negative (left side of a figure).

The corrected gear ratio command value calculation unit 630 multiplies the gear ratio pre-correction command value tRATIO calculated by the gear ratio command value calculation unit 61 by the gear ratio correction value γ to correct the corrected gear ratio command value cRATIO (= tRATIO). Xγ) is calculated.
Here, when the relative speed dVSP between the host vehicle and the preceding vehicle is zero (the vehicle speed of the preceding vehicle and the vehicle speed of the host vehicle are constant), the gear ratio correction value γ = 1, and the relative speed dVSP becomes lower (relative speed). Gradually increases) as the gear ratio correction value γ increases. That is, the lower the relative speed dVSP, the corrected gear ratio command value cRATIO is corrected, that is, the transmission 4 is corrected to the downshift side (low gear side).

  FIG. 16 shows changes in parameters in the conventional example, the present invention, and the apparatus. (A) shows a conventional example, and (B) shows an example of the present application. In the embodiment of the present application, the change in each parameter when the gear ratio correction values β and γ are calculated based on the inter-vehicle distance dist and the relative speed dVSP between the host vehicle and the preceding vehicle and the gear ratio command value cRATIO is calculated. Is shown. The horizontal axis represents time, and the vertical axis represents road surface gradient, vehicle speed, accelerator opening, drive torque command value, throttle opening, and gear ratio (the dotted line is the gear ratio command value and the solid line is the actual gear ratio).

  As illustrated, in the embodiment of the present application, when the inter-vehicle distance dist between the own vehicle and the preceding vehicle is short or the relative speed is small, the continuously variable transmission 4 is moved to the downshift side (low gear side), that is, The gear ratio correction values β and γ are increased. As a result, when the driver feels that the vehicle needs to be decelerated and releases the accelerator pedal, the continuously variable transmission 4 has already been shifted to the downshift side, so that deceleration by the engine brake of the vehicle can be achieved. A feeling of insufficient deceleration due to a response delay can be prevented.

Further, since the driving force distribution unit 600 calculates the engine torque command value cTE by feeding back the speed ratio, the driving torque does not change even if the speed ratio is corrected. Does not give the driver a sense of incongruity.
Next, processing performed by the corrected gear ratio command value calculation unit 630 when the vehicle enters a curved road will be described with reference to FIG.

FIG. 17 is a table for calculating the gear ratio correction value ε of the continuously variable transmission 4. The horizontal axis indicates the road curvature (1 / m), and the vertical axis indicates the gear ratio correction value ε. The higher the curvature (on the right side of the figure), the sharper the curve road is.
The corrected gear ratio command value calculation unit 630 multiplies the pre-speed ratio correction command value tRATIO calculated by the gear ratio command value calculation unit 610 by the gear ratio correction value ε to correct the corrected gear ratio command value cRATIO (= tRATIO). Xε) is calculated. Here, when the vehicle travels on a straight road, the gear ratio correction value ε = 1, and when the vehicle is a curved road, the gear ratio correction value ε is gradually increased according to the curvature of the road. That is, the greater the curvature of the road on which the vehicle is traveling and the tighter the curve (the more toward the right side of the figure), the corrected gear ratio command value cRATIO increases, that is, the transmission 4 is shifted to the downshift side (low gear side). Correct so that

FIG. 18 shows changes in parameters in the conventional example, the present invention, and the apparatus. (A) shows a conventional example, and (B) shows an example of the present application. The horizontal axis represents time, and the vertical axis represents road surface gradient, vehicle speed, accelerator opening, drive torque command value, throttle opening, and gear ratio (the dotted line is the gear ratio command value and the solid line is the actual gear ratio).
As illustrated, in the embodiment of the present application, when the vehicle enters the curved road, the continuously variable transmission 4 is increased on the downshift side (low gear side), that is, the speed ratio correction value ε. As a result, when the driver feels that the vehicle needs to be decelerated and releases the accelerator pedal, the continuously variable transmission 4 has already been shifted to the downshift side, so that deceleration by the engine brake of the vehicle can be achieved. A feeling of insufficient deceleration due to a response delay can be prevented.

Further, since the driving force distribution unit 600 calculates the engine torque command value cTE by feeding back the gear ratio, the driving torque does not change even if the gear ratio is corrected. There is no discomfort to the driver.
According to the present embodiment, the target drive torque setting means 400 and 440 that sets the target drive torque cTDR based on the driving state of the vehicle (target vehicle speed tVSP, vehicle speed aVSP), and the transmission 4 based on the target drive torque cTDR. Target speed ratio setting means 610 for setting the target speed ratio tRATIO, target engine torque setting means 620 for setting the target engine torque cTE based on the target drive torque cTDR and the actual speed ratio aRATIO, and speed change based on the target speed ratio tRATIO A vehicle driving force control device comprising a transmission ratio control means (transmission ECU) 30 for controlling the machine 4 and an engine control means (engine ECU) 20 for controlling the engine 1 based on a target engine torque cTE, The target gear ratio (speed ratio correction values α, β, γ Having a target gear ratio correcting means 630 for correcting the. For this reason, when the vehicle speed is high during traveling on a curved road by setting the target speed ratio based on the amount of turning state of the vehicle (curvature of the road) when the vehicle travels on a curved road, for example, When felt, there is an effect that a sufficient deceleration can be obtained only by the accelerator operation. In addition, even if the speed ratio of the continuously variable transmission 4 is corrected, the driving torque does not change, so that the driver does not feel uncomfortable by correcting the speed ratio.

  Further, according to the present embodiment, the target gear ratio correction means 630 corrects the target gear ratio tRATIO when the vehicle travels on a road having a gradient (speed ratio correction value α, FIGS. 12 and 13). For this reason, it is harder to decelerate on a downhill than on a flat road. Therefore, the driver releases the accelerator pedal by correcting the transmission ratio in advance, that is, by setting the transmission 4 to the downshift side (low gear side). This can give the driver a sufficient feeling of deceleration.

  Further, according to the present embodiment, the target gear ratio correction means 630 changes the correction value of the target gear ratio cRATIO according to the road gradient (speed ratio correction value α, FIGS. 12 and 13). For this reason, when the down slope is steep, the gear ratio is increased, that is, the continuously variable transmission 4 is changed to the downshift side (low gear side), while when the down slope is gentle, the gear ratio correction value. By reducing the value, an appropriate deceleration can be ensured when the driver releases the accelerator pedal.

  Further, according to the present embodiment, the target gear ratio correction means 630 corrects the target gear ratio cRATIO according to the inter-vehicle distance dist with the preceding vehicle (speed ratio correction value β, FIGS. 14 and 16). For this reason, when the inter-vehicle distance dist is reduced, the gear ratio is increased, that is, the continuously variable transmission 4 is set to the downshift side (low gear side), so that an appropriate deceleration is achieved when the driver releases the accelerator pedal. Can be secured.

  Further, according to the present embodiment, the target gear ratio correction means 630 corrects the target gear ratio tRATIO according to the relative speed difference dVSP with the preceding vehicle (speed ratio correction value γ, FIGS. 15 and 16). Therefore, when the relative speed dVSP is negative, that is, when approaching the preceding vehicle, the transmission ratio of the continuously variable transmission 4 is increased, that is, the transmission 4 is shifted to the downshift side (low gear side), thereby When the accelerator pedal is released, proper deceleration can be ensured.

  Further, according to the present embodiment, the target gear ratio correction means 630 corrects the target gear ratio tRATIO when the vehicle travels on a curved road (speed ratio correction value ε, FIGS. 17 and 18). For this reason, when the vehicle travels on a curved road, the transmission ratio of the continuously variable transmission 4 is increased, that is, when the transmission is shifted to the downshift side (low gear side), the driver releases the accelerator pedal. Appropriate deceleration can be ensured.

  Further, according to the present embodiment, the target gear ratio correction means 630 changes the correction value of the target gear ratio tRATIO according to the curvature of the road (speed ratio correction value ε). For this reason, when the curvature of the road is large, the transmission ratio of the continuously variable transmission 4 is increased, that is, the amount of downshift of the transmission 4 to the low gear side is greatly changed, while when the curvature of the road is small, the transmission By changing the downshift amount of 4 to be small, it is possible to ensure appropriate deceleration when the driver releases the accelerator pedal.

  Further, according to the present embodiment, the target gear ratio correction means 630 changes the correction value of the target gear ratio tRATIO according to the vehicle speed aVSP (speed ratio correction value ε). Therefore, when the vehicle speed aVSP when the vehicle travels on a curved road is high, the transmission ratio of the continuously variable transmission 4 is increased, that is, the amount of downshift of the transmission 4 to the low gear side is greatly changed, while the vehicle speed is If it is low, the gear ratio can be reduced to ensure proper deceleration when the driver releases the accelerator pedal.

  Further, according to the present embodiment, the target gear ratio correction means 630 corrects the target gear ratio tRATIO so that the transmission 4 is on the downshift side (low gear side). Therefore, when the driver needs to decelerate, the target transmission ratio tRATIO has already been corrected and the continuously variable transmission 4 is set to the low gear side, and the driver can decelerate the vehicle by releasing the accelerator pedal. .

The figure which shows the structure which concerns on embodiment of this invention The figure which shows the control structure which concerns on embodiment of this invention. The flowchart which shows operation (processing) of a control start judgment part The figure which shows the detailed structure of the target vehicle speed calculation part Target acceleration calculation map Flow chart showing the processing of the integration processing unit The figure which shows the structure of a vehicle control part Diagram showing configuration of vehicle model The figure which shows the structure of a driving force distribution part Gear ratio command value calculation map Throttle opening calculation map Gear ratio correction value calculation table The figure which shows the change of each parameter in a prior art example, this invention, and an apparatus Gear ratio correction value calculation table Gear ratio correction value calculation table The figure which shows the change of each parameter in a prior art example, this invention, and an apparatus Gear ratio correction value calculation table The figure which shows the change of each parameter in a prior art example, this invention, and an apparatus

Explanation of symbols

2 Engine rotation sensor 3 Throttle ACTR
13 Accelerator opening sensor 14 Vehicle speed sensor 15 Control start SW
16 Brake SW
20 Engine ECU
30 Transmission ECU
100 Vehicle speed control ECU
200 Control start determination unit 300 Target vehicle speed calculation unit 310 Target acceleration determination unit 320 Integration processing unit 400 Vehicle speed control unit 410 Phase compensator 420 Reference model 430 Feedback compensator 440 Drive torque conversion unit 500 Actual gear ratio calculation unit 600 Driving force distribution unit 610 Transmission ratio command value calculation unit 620 Engine torque command value calculation unit 630 Corrected transmission ratio command value calculation unit 640 Road surface gradient estimation unit 650 Road curvature estimation unit

Claims (9)

Target drive torque setting means for setting a target drive torque based on the driving state of the vehicle, target gear ratio setting means for setting a target speed ratio of the transmission based on the target drive torque, the target drive torque and the actual speed change Target engine torque setting means for setting a target engine torque based on the ratio; speed ratio control means for controlling the transmission based on the target speed ratio; engine control means for controlling the engine based on the target engine torque; A vehicle driving force control device comprising:
A driving force control apparatus for a vehicle, comprising: a target speed ratio correcting unit that corrects a target speed ratio according to a traveling state of the vehicle.   2. The vehicle driving force control apparatus according to claim 1, wherein the target gear ratio correcting means corrects the target gear ratio when the vehicle travels on a road having a gradient.   3. The vehicle driving force control apparatus according to claim 2, wherein the target gear ratio correction means changes a correction value of the target gear ratio in accordance with a road gradient.   2. The driving force control apparatus for a vehicle according to claim 1, wherein the target gear ratio correcting means corrects the target gear ratio in accordance with an inter-vehicle distance from a preceding vehicle.   2. The vehicle driving force control apparatus according to claim 1, wherein the target gear ratio correcting means corrects the target gear ratio in accordance with a relative speed difference with the preceding vehicle.   2. The driving force control apparatus for a vehicle according to claim 1, wherein the target gear ratio correcting means corrects the target gear ratio when the vehicle travels on a curved road.   7. The vehicle driving force control apparatus according to claim 6, wherein the target gear ratio correcting means changes a correction value of the target gear ratio in accordance with a curvature of the road.   7. The vehicle driving force control apparatus according to claim 6, wherein the target gear ratio correcting means changes a correction value of the target gear ratio in accordance with a vehicle speed.   9. The vehicle driving force control device according to claim 1, wherein the target gear ratio correction unit corrects the target gear ratio so that the transmission is on a downshift side. 10. .

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