KR101860192B1 - Driving force control system for vehicle - Google Patents

Abstract

There is provided a driving force control apparatus for a vehicle that includes an automatic transmission that shifts a torque output from an engine and transmits the torque to a drive wheel, and controls the driving force based on the vehicle speed and the accelerator opening. Wherein said control means stores an acceleration characteristic that defines a relationship between an acceleration and a vehicle speed when a vehicle is decelerated, (Step S3), based on the running data of the vehicle and the acceleration characteristic. Then, before starting the re-acceleration running, the obtained speed ratio is set so as to realize the acceleration in the re-acceleration (step S4).

Description

[0001] DRIVING FORCE CONTROL SYSTEM FOR VEHICLE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force control apparatus for a vehicle that controls a driving force of a vehicle by changing a speed ratio of an automatic transmission at the time of decelerating the vehicle.

Japanese Patent Laying-Open No. 2007-170444 discloses a driving force control apparatus for a vehicle that executes deceleration assist control including control for prohibiting an upshift when the accelerator of the vehicle is stopped and controlling downshifting at the same time . The driving force control apparatus disclosed in Japanese Patent Application Laid-Open No. 2007-170444 is configured to determine the conditions of the deceleration assist control as described above on the basis of the running environment and the running state of the vehicle. For example, the control level when the deceleration assist control is performed and the deceleration assist control is performed is determined according to the headway distance, the road surface gradient, or the driving direction of the driver ahead. Japanese Patent Application Laid-Open No. 2007-170444 discloses a control example in which, when the deceleration assist control is executed, downshifting to a lower speed stage is possible when the driver's driving orientation is sport-oriented. The sports driving orientation is driving-oriented, which emphasizes the power performance of the vehicle and requires prompt response of the vehicle to the driving operation.

Japanese Patent Application Laid-Open No. 2003-211999 discloses a running control apparatus that automatically follows a preceding vehicle to a preceding vehicle. The running control device disclosed in Japanese Patent Application Laid-Open No. 2003-211999 samples running data representing the behavior of the vehicle, the running environment, the driving operation, and the like at the time of running by the driver's operation, The driver's driving orientation (a heavy regression coefficient) is obtained. Then, by setting the target acceleration / deceleration based on the driving direction, the subject vehicle is automatically followed by the preceding vehicle.

Further, the driving force control device disclosed in Japanese Patent Application Laid-Open No. 2002-139135 calculates the recommended speed ratio based on the driving environment of the road, and calculates the optimum speed ratio based on the recommended speed ratio, the shifting intention by the driver, And changes the optimum speed ratio to a changing speed determined by the difference between the recommended speed ratio and the actual speed ratio.

As described above, in the control device described in Japanese Patent Application Laid-Open No. 2007-170444, the driving orientation of the driver is estimated at the time of driving the vehicle. When the driving direction is the sport driving direction, for example, at the corner or the deceleration in front of the intersection, the vehicle is downshifted to the lower speed end as compared with the case where the driving direction is not the sports driving direction. The downshifting is performed at the time of deceleration, so that the acceleration performance when the vehicle is reattached after braking can be improved.

On the other hand, in the control device described in Japanese Patent Application Laid-Open No. 2007-170444, the speed change stage is uniformly set in accordance with whether the driver's driving orientation is a sport driving orientation at the time of deceleration before a corner or an intersection point, All. In addition, since the driving orientation is a value obtained by estimation, it inevitably includes the individual difference and the estimation error of the driver. As a result, the speed change stage or the speed change ratio after downshifting may not be appropriate. For example, when the downshift is insufficient, there may be a case where the downshifting is further performed when the driver depresses the accelerator pedal to accelerate after the turning at the corner. That is, there is a case where the driving force actually generated for the requested driving force intended by the driver becomes insufficient. As a result, there is a possibility that the driver feels a sense of incongruity or feels that acceleration performance or accelerated filling is not good.

An object of the present invention is to provide a vehicle having an automatic transmission and a method of controlling the vehicle so as to be capable of operating a vehicle having an automatic transmission, ) Of the vehicle, thereby allowing the vehicle to travel at a constant speed.

Therefore, according to one aspect of the present invention, there is provided a driving force control apparatus for a vehicle having an engine, a drive wheel, and an automatic transmission transmitting torque between the engine and the drive wheel. The driving force control apparatus for a vehicle has a controller. The controller controls the driving force of the vehicle on the basis of (i) a vehicle speed and an accelerator opening degree, (ii) stores an acceleration characteristic in which a relationship between an acceleration and a vehicle speed is determined during a re-acceleration, (Iii) obtaining acceleration at the time of re-acceleration corresponding to the current vehicle speed on the basis of the running data and the acceleration characteristic of the vehicle before the deceleration running, (iv) a speed ratio of the automatic transmission capable of realizing the acceleration at the time of re-acceleration based on the obtained acceleration at the time of re-acceleration before starting the re-acceleration running.

(I) estimating an expected vehicle speed desired by the driver when the vehicle is in the re-acceleration running based on the running data at the time of acceleration running before the deceleration running, (ii) ) May be configured to determine the acceleration at the time of re-acceleration corresponding to the current vehicle speed on the basis of the current vehicle speed and the estimated expected vehicle speed.

In the driving force control apparatus, the controller may be configured to: (i) store a plurality of acceleration characteristic lines in which acceleration is determined according to a vehicle speed in the re-acceleration; (ii) And (iii) the accelerating acceleration corresponding to the current vehicle speed on the basis of the current vehicle speed and the expected vehicle speed and the selected acceleration characteristic line.

Further, in the driving force control apparatus, the controller may be configured to store the vehicle speed and the acceleration at the time of starting the rebuilding running, and to update the acceleration characteristic line.

Further, in the driving force control apparatus, the controller may further include: (i) an acceleration sensor that detects acceleration or deceleration of the accelerator pedal by using the average value of the accelerations during the re-acceleration or the average value of the expected vehicle speed, And (ii) setting the calculated speed ratio to realize the obtained acceleration at the time of re-acceleration.

In the driving force control device, the controller may be configured to set the maximum vehicle speed recorded by the vehicle as the expected vehicle speed before starting the deceleration running from the time when the expected vehicle speed is not set.

In the driving force control apparatus for a vehicle according to the present invention, an automatic transmission capable of accelerating the vehicle at the time of re-acceleration, that is, the acceleration expected by the driver, until the vehicle starts running again after the vehicle is decelerated (Or a speed change stage) is set. The acceleration at the time of the ashes acceleration is a control index at the time of the ashes running after the deceleration running, and is an estimate of the acceleration desired by the driver or the acceleration expected by the driver at the time of ashes running. The acceleration at the time of the ashes acceleration is obtained on the basis of the acceleration characteristic stored in advance and the running data of the vehicle before the deceleration running. The acceleration characteristic defines the relationship between the acceleration and the vehicle speed in the re-acceleration, and can be stored in advance. The running data of the vehicle is a physical quantity representing the running state of the vehicle such as a vehicle speed, an acceleration, a speed ratio of the automatic transmission, or an engine speed, for example.

Therefore, according to the driving force control apparatus for a vehicle of the present invention, it is possible to perform the shift control of the automatic transmission that sets the speed ratio that allows the vehicle to accelerate at the accelerating speed when the vehicle is accelerating again I can finish it. In addition, the accelerations at the time of re-acceleration can be obtained from the acceleration data of the vehicle before the deceleration and the acceleration characteristics of the vehicle as described above, so that the acceleration at the time of acceleration can be used as a control index of the shift control that reflects the intention of the driver, have. As a result, the automatic transmission can set a speed ratio at which the drive force necessary for re-acceleration can be obtained at the start point of the re-acceleration running after the deceleration running. The speed ratio set at that time is a speed ratio estimated to be capable of accelerating the vehicle at an acceleration desired by the driver or an acceleration requested by the driver.

For example, in the case where the vehicle turns on a corner, during the deceleration running of the vehicle in the turning travel stage from the entrance to the corner to the corner, The automatic transmission can be downshifted with an appropriate speed ratio (speed change stage), that is, the accelerating speed at the time of re-acceleration. Therefore, when the vehicle enters a corner and turns, it is possible to steadily make a turning operation by appropriately decelerating the vehicle while maintaining a state in which a large driving force can be obtained. Then, when the vehicle starts to escape from the corner and starts to accelerate again, the downshift is completed to a state where it is possible to obtain a sufficient driving force as described above.

As described above, according to the driving force control apparatus for a vehicle of the present invention, since the downshift at the time of deceleration traveling is insufficient, avoiding further downshift to compensate for the insufficiency of the driving force at the time of after- Can be accelerated. Thus, it is possible to suppress the driver from feeling a sense of incongruity or shock, and to improve the acceleration performance and acceleration filling of the vehicle.

The features, advantages, and technical and industrial significance of the exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like elements are represented by like numerals.
1 is a diagram showing a configuration of a vehicle and an example of a control system to be controlled by the driving force control apparatus for a vehicle according to the present invention.
2 is a flowchart for explaining an example of basic driving force control by the vehicle driving force control apparatus of the present invention.
Fig. 3 is a diagram for explaining the correlation between the " acceleration during acceleration " and the vehicle speed calculated for calculating the " expected vehicle speed " and " acceleration during acceleration " in the driving force control of the present invention.
Fig. 4 is a diagram for explaining a correlation line (approximate line) in the correlation shown in Fig.
Fig. 5 is a view for explaining an example of a control map for obtaining " acceleration at the time of re-acceleration " in the driving force control of the present invention.
Fig. 6 is a diagram for explaining control for obtaining the "output allowable acceleration" and the output range of the output enable acceleration (speed ratio) in the driving force control of the present invention.
Figs. 7A and 7B are diagrams for explaining the behavior (vehicle speed, acceleration, engine speed, and the like) of the vehicle when the driving force control of the present invention is executed.
8 is a block diagram for explaining a configuration of a controller constituting a driving force control apparatus for a vehicle according to the present invention.
9A and 9B are diagrams for explaining the behavior (vehicle speed, acceleration, engine speed, and the like) of the vehicle when the driving force control of the present invention is executed for a vehicle equipped with a continuously variable transmission.
Fig. 10 is a diagram for explaining another control example in the case where the driving force control of the present invention is executed for a vehicle equipped with a continuously variable transmission.
11A and 11B are diagrams for explaining another control example in the case where the driving force control of the present invention is executed.
12A and 12B are diagrams for explaining another control example in the case where the driving force control of the present invention is executed.
13 is a view for explaining another control example in the case where the driving force control of the present invention is executed.
14 is a diagram for explaining another control example in the case where the driving force control of the present invention is executed.
15 is a diagram for explaining another example of the control map shown in Fig.
16 is a diagram for explaining another example of the control map shown in Fig.
17 is a flowchart for explaining another driving force control by the vehicle driving force control apparatus of the present invention.
18 is a time chart for explaining an example of obtaining an " expected vehicle speed " in the driving force control of the flowchart shown in Fig.
19 is a flowchart for explaining another driving force control by the vehicle driving force control apparatus of the present invention.
20 is a flowchart for explaining another driving force control by the vehicle driving force control apparatus of the present invention.
Fig. 21 is a diagram for explaining a calculation method of an approximate line of running data with respect to control for weighting running data for obtaining "expected vehicle speed" and "acceleration at the time of acceleration".
22 is a diagram for explaining the effect of weighting on the running data.
23 is a diagram for explaining an example of learning control of a coefficient (slope) that defines a correlation line for obtaining an " expected vehicle speed " and a " acceleration at acceleration " in the driving force control of the present invention.
Fig. 24 is a view for explaining another example of learning control of a coefficient (slope) that defines a correlation line for obtaining an " expected vehicle speed " and " acceleration at acceleration " in the driving force control of the present invention.
25 is a flowchart for explaining another example of driving force control by the vehicle driving force control apparatus of the present invention.

Next, an embodiment of the present invention will be described with reference to the drawings. A vehicle to which the present invention can be applied is a vehicle equipped with an automatic transmission capable of shifting the power output from the engine and transmitting it to the drive wheels. The automatic transmission of the present invention may be a continuously variable transmission capable of continuously changing the speed ratio, such as a belt type continuously variable transmission or a toroidal type continuously variable transmission. The present invention can also be applied to a hybrid vehicle having a power dividing mechanism for synthesizing and dividing the power output from the engine and the motor. Namely, since the power split mechanism in such a hybrid vehicle functions as a so-called electric continuously-variable transmission mechanism, such an electric-powered continuously-variable transmission mechanism can also be included in the automatic transmission of the present invention.

Fig. 1 shows a configuration of a vehicle equipped with an automatic transmission on the output side of the engine and a control system as an example of a vehicle to which the present invention can be applied. The vehicle Ve shown in Fig. 1 has a front wheel 1 and a rear wheel 2. 1, the vehicle Ve transmits the power output from the engine (ENG) 3 to the rear wheel 2 through the automatic transmission (AT) 4 and the differential gear set 5 So as to generate a driving force. The vehicle Ve to which the present invention can be applied is also a front wheel drive vehicle that transmits the power output from the engine 3 to the front wheel 1 to generate a driving force. Alternatively, it may be a four-wheel drive vehicle that transmits the power output from the engine 3 to the front wheel 1 and the rear wheel 2 to generate a driving force.

The engine 3 is provided with, for example, an electronically controlled throttle valve or an electronically controlled fuel injection device and an air flow sensor for detecting the flow rate of intake air. In the example shown in Fig. 1, an electronic throttle valve 6 and an air flow sensor 7 are provided. Therefore, the output of the engine 3 can be automatically controlled by electrically controlling the operation of the electronic throttle valve 6 based on detection data of the accelerator sensor 9, which will be described later.

An automatic transmission 4 for shifting the output torque of the engine 3 and transmitting it to the drive wheel side is provided on the output side of the engine 3. [ The automatic transmission 4 is a conventional universal step automatic transmission including, for example, a planetary gear mechanism and a clutch / brake mechanism. The automatic transmission 4 controls the operation of the clutch mechanism and the brake mechanism, (Or speed ratio) of the vehicle.

A controller 8 for controlling the output of the engine 3 and the shifting operation of the automatic transmission 4 is provided. The controller 8 is, for example, an electronic control unit (ECU) configured by a microcomputer as a main body. The engine (3) is connected to the controller (8) so as to enable communication for control. The automatic transmission 4 is connected to the controller 8 via a hydraulic control device (not shown) so as to enable communication for control. Although FIG. 1 shows an example in which one controller 8 is installed, a plurality of controllers 8 may be provided for each device or device to be controlled or for each control content.

The controller 8 is configured to receive detection signals from various kinds of sensors of various parts of the vehicle Ve, information signals from various on-vehicle devices, and the like. For example, the airflow sensor 7, the accelerator sensor 9 for detecting the accelerator opening degree, the brake sensor (or brake switch) 10 for detecting the amount of the brake pedal applied, An output rotational speed sensor 12 for detecting the rotational speed of the output shaft 4a of the automatic transmission 4 and an output rotational speed sensor 12 for detecting the rotational speed of each of the wheels 1, A detection signal from the vehicle speed sensor 13 or the like for detecting the rotational speed and obtaining the vehicle speed is inputted to the controller 8. [ Then, it is configured to perform calculation using the input data and pre-stored data, and output the control command signal based on the calculation result.

In the vehicle Ve structured as described above, there is a case where the downshift is performed by the driver depressing the accelerator pedal when the vehicle Ve continues to decelerate after the vehicle decelerates. If the downshifting performed at the time of deceleration travel is not appropriate, the downshift is performed to lower the speed change stage (increase the speed change ratio) at the time of restarting the running due to insufficient driving force at the time of ash running. As a result, the driver feels a sense of incongruity or feels that the accelerated filling is not good. The driver's intention and driving orientation also change depending on the individual difference of the driver, the driving environment, and the like. On the other hand, if the downshift at the time of the decelerating operation is performed uniformly, there is a possibility that the driving force or the acceleration intended by the driver may not be obtained at the time of starting the re-acceleration running.

Therefore, the controller 8 is constructed so that the vehicle Ve is able to continue running at a proper speed by reflecting the intention of the driver and the driver's intention to the control and controlling the driving force of the vehicle Ve. Specifically, the controller 8 obtains the " accelerating acceleration " as a control index when the vehicle Ve is decelerating and running after the vehicle is decelerating, and calculates the " Speed acceleration " of the automatic transmission 4 is set. The " accelerating acceleration during acceleration " is a control index at the time of ashes running after deceleration, and the accelerations desired by the driver or the accelerations expected by the driver are estimated at the time of accelerating. This " acceleration at the time of re-acceleration " is obtained based on the acceleration characteristic and the running data of the vehicle Ve. The acceleration characteristic defines the relationship between the "accelerating acceleration" and the vehicle speed, and is stored in advance in the form of, for example, an equation or a map. The running data of the vehicle Ve is a physical quantity representing the running state of the vehicle Ve, for example, the vehicle speed, the acceleration, the speed ratio of the automatic transmission 4, or the engine speed, / RTI > The present running history prior to deceleration running means that if the controller 8 is configured to clear the running data when the ignition switch (or the main switch) is turned OFF, the running history of the vehicle Ve Is the history of the travel data acquired from the time point when the ignition switch is turned ON to when the control described in Fig.

More specific control executed by the controller 8 is described below. Fig. 2 is a flowchart for explaining an example of control as a basic operation. First, it is judged whether or not the acceleration running of the vehicle Ve has been completed (step S1). For example, based on the detection values of the vehicle speed sensor 13 or the longitudinal acceleration sensor (not shown), it is possible to determine whether or not the acceleration running has ended. It is to be noted that it is determined that the acceleration running of the vehicle Ve has ended in this step S1 if the acceleration of the vehicle Ve is 0 once after it is determined that the vehicle Ve is accelerating, Or to a deceleration running in which the acceleration of the vehicle Ve becomes 0 or less. Or when the brake switch 10 is turned ON. Therefore, in all other cases, it is judged negative in step S1. For example, when the vehicle Ve is accelerating, when the vehicle Ve is decelerating, or when the vehicle Ve is running normally, if the acceleration Ve is not yet accelerated after the start of the control, , It is determined to be negative in step S1.

When the accelerating operation of the vehicle Ve is completed and it is determined in step S1 that this is positive, the process proceeds to step S2. In step S2, the expected vehicle speed Vexp and the gradient coefficient K are calculated and updated. Specifically, the running data (e.g., the vehicle speed at the start of acceleration, the maximum acceleration during acceleration running, etc.) of the vehicle Ve stored during the acceleration running determined to be completed in step S1 is read and based on the running data , The expected vehicle speed Vexp and the gradient coefficient K are updated. When the driver drives the vehicle Ve, it can be assumed that the driver is always driving with a predetermined vehicle speed. In the control by the controller 8, the target vehicle speed or the vehicle speed estimated by the driver as described above is defined as " expected vehicle speed ". Generally, under the same driving environment, when the driving orientation of the driver becomes driving oriented (sports driving oriented) that emphasizes power performance and performance, the "expected vehicle speed" becomes high. On the other hand, when the driver's driving orientation becomes more driving oriented (fuel economy driving oriented) that emphasizes fuel economy and efficiency than usual, the "expected vehicle speed" is lowered. The expected vehicle speed Vexp can be obtained on the basis of the running history of the vehicle Ve in which data such as vehicle speed, longitudinal acceleration, lateral acceleration, steering angle, road surface gradient, and vehicle posture are recorded. The gradient coefficient K indicates the slope of the correlation line used to obtain the " expected vehicle speed " as will be described later. Details of the expected vehicle speed Vexp and the gradient coefficient K will be described later.

On the other hand, if it is determined as negative in step S1, the process proceeds to step S3. In step S3, the respective previous values of the expected vehicle speed Vexp and the gradient coefficient K are maintained. That is, the expected vehicle speed Vexp and the gradient coefficient K, which are calculated and stored when the previous acceleration running ends, are held until the current acceleration running is finished. If the acceleration running has not yet been performed after the start of the control, for example, the ignition switch is turned ON for the current running, and the expected vehicle speed Vexp and the gradient coefficient K continues to be maintained. In the configuration in which the expected vehicle speed Vexp and the gradient coefficient K are cleared when the ignition switch is turned OFF, each preset initial value is read when the ignition switch is turned ON, and is stored as the expected vehicle speed Vexp and the gradient coefficient K. Therefore, when the acceleration running has not yet been performed after the start of the control as described above, the initial values of the expected vehicle speed Vexp and the gradient coefficient K are maintained. In the configuration in which the expected vehicle speed Vexp and the gradient coefficient K at that time point are stored when the ignition switch is turned OFF, if the acceleration running is not yet performed after the start of the control as described above, , The expected vehicle speed Vexp and the gradient coefficient K are read and held continuously.

When the expected vehicle speed Vexp and the gradient coefficient K are updated in step S2, or when the respective previous values of the expected vehicle speed Vexp and the gradient coefficient K are maintained in step S3, the routine goes to step S4. In step S4, the acceleration Gexp at the time of re-acceleration is obtained. When the vehicle Ve is decelerating without stopping, the vehicle transits to a state in which the vehicle continues to run after decelerating. For example, when the vehicle Ve turns on a corner, the vehicle Ve usually enters the corner while decelerating in front of the corner. In the corner, the vehicle is turning at a constant speed or decelerating. Then, when you escape the corner, the ashes run. In this way, when the vehicle Ve is running after the vehicle decelerates, it can be assumed that the driver accelerates the vehicle Ve toward the expected vehicle speed Vexp. Therefore, if the vehicle speed difference? V (? V = Vexp-Vcur) between the expected vehicle speed Vexp and the current vehicle speed Vcur is large, the driver will demand a large acceleration to reduce the vehicle speed difference? V and presumably drive the vehicle Ve again .

Based on the above assumption, in this step S4, the accelerating acceleration Gexp is obtained from the vehicle speed difference? V between the expected vehicle speed Vexp and the present vehicle speed Vcur as the acceleration expected by the driver at the time of re-acceleration running. For example, as shown in Fig. 3 and Fig. 4, it can be seen that there is a negative correlation between the above-described " acceleration during acceleration " and the vehicle speed from the results of running tests and simulations. Assuming that the vehicle speed at the time of starting the rebuilding running is the x axis and the acceleration (maximum earth acceleration) at that time is the y axis, the correlation of the linear function represented by "y = a x x + b" A line (approximate line) can be obtained. A correlation line, as shown by a broken line f _1, f _2, f ₃ in Fig. 3 can be obtained every two driving orientation of the driver.

As described above, the " expected vehicle speed " is defined as the vehicle speed targeted by the driver at the time of acceleration running. As a result, when the vehicle speed reaches the " expected vehicle speed ", it is unnecessary to accelerate the abnormal vehicle Ve, and as a result, it can be assumed that the acceleration becomes zero. Therefore, the " expected vehicle speed " can be obtained by calculating the x-intercept (-b / a) in which the y-axis acceleration becomes zero in the correlation line of the linear function as shown in Fig.

The earth acceleration is an acceleration that can be obtained as a differential value of detection data of the output rotation speed sensor 12 or the vehicle speed sensor 13, for example. The acceleration can be obtained by the acceleration sensor mounted on the vehicle Ve. In this case, however, there is a possibility that noise is generated in the detection data of the acceleration under the influence of the posture or the road surface gradient of the vehicle Ve. Therefore, in this control, the earth acceleration obtained from the above-mentioned rotation speed sensor is used.

The relationship between the "acceleration at the time of acceleration" and the vehicle speed is previously determined as the acceleration characteristic of the vehicle Ve and stored in the controller 8 by using the correlation between the "acceleration during acceleration" have. By determining such an acceleration characteristic as a function of the vehicle speed, it is possible to calculate the " accelerating acceleration " corresponding to the " expected vehicle speed "

In the driving force control by the controller 8, the running data at the time of starting the restart running can be stored, and the acceleration characteristic in which the relationship between the "acceleration at the time of restart" and the vehicle speed is determined can be updated. The traveling data stored in this case is the vehicle speed and the acceleration of the vehicle Ve at the time of starting the re-acceleration running. The above-described acceleration characteristic is stored as an acceleration characteristic line determined, for example, by " acceleration during acceleration " according to the vehicle speed. Concretely, the acceleration characteristic line is a correlation line (approximate line) as indicated by "y = a × x + b" in FIG.

In addition, the " acceleration at the time of rest speed " corresponding to the " expected vehicle speed " and the " current vehicle speed " can be obtained from a control map as shown in FIG. 5, for example. In other words, the relationship between the "accelerating acceleration" and the vehicle speed is previously determined using the correlation between the vehicle "Ve (acceleration)" and the vehicle speed using the correlation between the vehicle acceleration and the vehicle speed obtained from the driving history or running information at the time of the previous acceleration running. , And can store it in the controller 8 as a control map as shown in Fig.

In Fig. 5, the line f corresponds to the correlation line "y = a x x + b" described above, and shows the acceleration characteristic in which the relationship between the "acceleration during acceleration" and the vehicle speed is determined. The slope of this straight line f represents the gradient coefficient K. In the straight line f, the vehicle speed at which the ground acceleration becomes zero, that is, the x-intercept of the straight line f is the " expected vehicle speed ". 5, the current vehicle speed Vcur is applied to the relational expression expressed by the straight line f and the gradient coefficient K for the line f passing through the expected vehicle speed Vexp obtained in the above-mentioned step S2 to obtain the accelerating speed Gexp .

Further, as indicated by, for example, the straight line fs and the straight line fm in Fig. 5, the straight line f may be set a plurality of times according to the " expected vehicle speed " In this case, the predetermined straight line f among a plurality of sets of correlation lines is determined from the running history at the time of the previous acceleration running. At the same time, an " expected vehicle speed " is obtained as the x-intercept of the straight line f. Thus, the " expected vehicle speed " obtained based on the history at the time of the previous acceleration running is reflected in the driving direction shown at the time of the previous acceleration running. Then, the " accelerating acceleration " is obtained based on the " expected vehicle speed " obtained as described above and the " current vehicle speed " obtained as the detected value of the vehicle speed sensor 13, for example. As shown in FIG. 5, the larger the difference between the "expected vehicle speed" and the "current vehicle speed" is, the larger the "accelerating acceleration" is. Further, the stronger the driving direction as the driving direction, the more the straight line fs having the " expected vehicle speed " is selected, and the " accelerating acceleration " Conversely, the stronger the fuel-economy driving direction is as the driving direction, the smaller the "expected vehicle speed" is selected as the straight line fm, and the "accelerating acceleration" obtained by this is also reduced.

When the acceleration Gexp in the re-acceleration is obtained in the above-described manner at step S4, the speed change stage of the automatic transmission 4 capable of realizing the acceleration Gexp at the re-acceleration is obtained (step S5). That is, the optimum speed change stage set by the automatic transmission 4 for accelerating to the acceleration Gexp when the vehicle Ve is accelerating again is obtained. An example of a method for obtaining such a gear position is shown in Fig. First, the outputable acceleration Gabl is set. Output allowable acceleration Gabl is calculated from a calculation formula of Gabl = (Te _max x gR) / W, where Te _max is the maximum value of the output torque of the engine 3, R is the running resistance, W is the vehicle weight, and g is the gear ratio . As shown in Fig. 6, the output allowable acceleration Gabl is calculated for each gear position of the automatic transmission 4.

6 shows an example in which the automatic transmission 4 is an 8-speed step-variable transmission. In the example shown in Fig. 6, the speed change stage capable of attaining the " accelerating acceleration " with respect to the " accelerating acceleration " obtained from the " expected vehicle speed & The second speed, the second speed, the third speed, the fourth speed and the fifth speed) is selected. That is, in FIG. 6, acceleration acceleration Gexp is displayed as an intersection of a correlation line passing through the expected vehicle speed Vexp and a straight line indicating the current vehicle speed Vcur. The point indicating the acceleration Gexp in the acceleration state is located between the fifth-speed output allowable acceleration Gabl and the sixth-speed output allowable acceleration Gabl. This means that when the maximum torque is output from the engine 3 and the sixth speed or more of the speed change stages (sixth speed, seventh speed, eighth speed) is set in the automatic transmission 4, the acceleration Gexp It can not be achieved. Therefore, in the example shown in Fig. 6, the fifth speed, which is the fastest one of the fifth speed or lower speed range (fifth speed to second speed) of the automatic transmission 4 capable of achieving acceleration acceleration, do.

When the speed change stage (speed ratio) of the automatic transmission 4 capable of realizing the accelerating speed Gexp at the re-acceleration is calculated in step S5, it is judged whether the vehicle Ve is decelerating or not (step S6). It is possible to determine whether the vehicle Ve is decelerating on the basis of the detected value of the vehicle speed sensor 13 or the longitudinal acceleration sensor (not shown) or the operation signal of the brake switch 10, for example. If the vehicle Ve is judged to be negative in the step S6 because it is not in the deceleration running state, this routine is once terminated without performing the subsequent control.

On the other hand, if the vehicle Ve is judged to be positive in step S6 because of the deceleration running, the process proceeds to step S7. In step S7, it is determined whether or not the gear position currently set in the automatic transmission 4 is a higher gear position than the gear position calculated in step S5, that is, whether or not the gear ratio of the current gear position is smaller than the gear ratio of the calculated gear position Is determined. The present speed change stage is slower than the calculated speed change stage, and if the negative determination is made in step S7, this routine is once terminated without performing the subsequent control.

On the other hand, if the current speed change stage is higher than the calculated speed change stage and the determination in step S7 is affirmative, the process proceeds to step S8 and a downshift is performed in the automatic transmission 4 toward the calculated speed change stage . Then, this routine is once terminated.

Figures 7a, 7b in the illustrated image of the operation of the base vehicle speed V for _A, and the expected vehicle speed (Ve) in the case where the running speed reduction in two cases of the case of lower vehicle speed than the expected V _A V _B. As shown in Fig. 7A, downshifting is performed at shift points (black circles) on the correlation line corresponding to the respective expected vehicle speeds V _A and V _B. Fig. 7B is a diagram showing the conversion points shown in Fig. 7A in terms of the engine speed. _A downshift is performed approximately at the rotation speeds A and B corresponding to the respective expected vehicle speeds V _A and V _B.

A specific configuration of the controller 8 for executing the control at the time of deceleration running is shown in the block diagram of Fig. 8, the controller 8 includes an acceleration calculating section B1, an expected vehicle speed calculating section B2, an acceleration acceleration calculating section B3, an output allowable acceleration calculating section B4, A target speed change stage calculation unit B5, and a shift output determination unit B6.

The acceleration calculating section B1 calculates the acceleration of the vehicle Ve based on the detection data of the output rotation speed sensor 12. [ It is also possible to calculate the acceleration of the vehicle Ve from the detection data of the vehicle speed sensor 13. [ The expected vehicle speed calculating section B2 calculates the expected vehicle speed Vexp based on the acceleration data calculated by the acceleration calculating section B1 and the detection data of the vehicle speed sensor 13. [ The ashing acceleration calculating section B3 calculates the acceleration acceleration Bmax based on the vehicle speed difference? V between the expected vehicle speed Vexp calculated in the expected vehicle speed calculating section B2 and the current vehicle speed Vcur determined from the detected data of the vehicle speed sensor 13 Time acceleration Gexp. On the other hand, the output-capable acceleration calculation unit B4 calculates the output-possible acceleration Gabl for each speed change stage (or speed ratio) of the automatic transmission 4 on the basis of the detection data of the air flow sensor 7. The target speed change stage calculating section B5 calculates the target speed change stage B5 based on the accelerating acceleration Gexp calculated at the acceleration acceleration calculating section B3 and the outputable acceleration Gabl calculated at the output possible acceleration calculating section B4 4) is calculated based on the target speed change ratio (or the target speed change ratio). The transmission output determination unit B6 determines the output of the automatic transmission 1 based on the target shift stage calculated by the target shift stage calculation unit B5 and the detection data of the accelerator sensor 9 and the detection data of the brake switch 10. [ 4 on the basis of the shift command. More specifically, it is determined whether or not the downshift to the automatic transmission 4 is required to be executed.

6, 7A and 7B illustrate an example in which the automatic transmission 4 is an 8-speed step-variable transmission of the present invention. However, the automatic transmission 4 of the present invention is not limited to the belt type, the toroidal type continuously variable transmission, The present invention is not limited to this. When the automatic transmission 4 is the continuously variable transmission or the electric continuously-variable transmission of the hybrid vehicle as described above, the transmission ratio of the automatic transmission 4 capable of realizing the " acceleration at the time of re-acceleration " is calculated. Based on the calculated transmission ratio, The automatic transmission 4 is controlled. For example, as shown in Fig. 9A, the speed ratio? Capable of realizing the " accelerating acceleration " is obtained from the "current vehicle speed" and the "expected vehicle speed", and the automatic transmission 4 is controlled do. The behavior of the engine speed in this case is shown in Fig. 9B.

In the case where the automatic transmission 4 is the continuously variable transmission or the electric continuously-variable transmission of the hybrid vehicle, if the deceleration continues even after the downshift to increase the speed ratio at the time of deceleration running, as shown in Fig. 10, (Solid line) in accordance with the vehicle speed in a range that does not fall below the acceleration output allowable revolution speed (broken line) in the re-acceleration in FIG. 10, . Thereby, it is possible to provide an appropriate deceleration feeling to the driver at the time of deceleration running.

In the case where the vehicle Ve is decelerated to run based on the "expected vehicle speed" and the "acceleration at the time of acceleration" as described above, it is also possible to control to change the use region of the engine speed according to the magnitude of the "expected vehicle speed". For example, in the case of the example, as shown in Figure 11, the expected vehicle speed V _c, and the expected vehicle speed V _c than in the case that the running speed reduction in two cases of the case of the low forward speed V _d, they expected vehicle speed V _c, V _d Is obtained from the map shown in Fig. 11A, respectively. In this case, the minimum engine speed is the lower limit engine speed that should be secured to accelerate the vehicle Ve to " accelerating acceleration " at the time of acceleration running after the deceleration running. Then, as shown in Fig. 11B, a downshift is performed at the time of deceleration running with the lowest engine speed obtained as described above as the lower limit. 11B shows an example in which the automatic transmission 4 is an 8-speed step-variable transmission. However, control at the time of deceleration running as shown in Figs. 11A and 11B is performed only when the automatic transmission 4 is a continuously variable transmission The present invention can also be applied to an electrically controlled stepless transmission mechanism of a hybrid vehicle. By controlling in this manner, downshifting at the time of deceleration running can be made to have regular regularity, and running peeling given to the driver at the time of downshifting can be made good.

11A and 11B illustrate an example in which the downshift is performed with the lowest engine rotational speed predetermined as the lower limit at the time of deceleration running. However, when the maximum engine rotational speed is set and the maximum engine rotational speed is set to the upper limit Thereby performing a downshift at the time of deceleration running. For example, as shown in A, B of Figure 12, expected vehicle speed for V _e, and expected vehicle speed when traveling the deceleration in two cases of the case of the low forward speed than V _e V _f, they expected vehicle speed V _e , and _Vf are obtained from the map shown in Fig. 12A, respectively. In this case, the maximum engine speed is the range of the engine speed to be secured in order to accelerate the vehicle Ve to the " accelerating acceleration " at the time of acceleration running after the deceleration running, Is an upper limit engine speed set so that the engine speed does not rise excessively. Then, as shown in Fig. 12B, downshifting at the time of deceleration running is performed with the maximum engine speed thus obtained as the upper limit. 12B shows an example in which the automatic transmission 4 is an 8-speed step-variable transmission. However, the control at the time of deceleration running shown in Figs. 12A and 12B is also similar to that shown in Figs. The automatic transmission 4 can be applied to a continuously variable transmission or an electrically controlled continuously variable transmission of a hybrid vehicle.

In the above-described embodiment, the downshifting is controlled based on the " expected vehicle speed " and the " current vehicle speed " It is also possible to control to perform downshifting at predetermined intervals. For example, as shown in Fig. 13, downshifting at the time of deceleration running is performed at regular intervals of the period t. The period t in this case can be set in advance according to the driving direction of the driver. For example, when the driving direction is the sport driving direction, the downshifting is performed at regular intervals of a shorter time period t. The interval of the downshift in this case is set in the range of the speed change stage (speed ratio) at which the " output enable acceleration " obtained based on the " acceleration at the time of re-acceleration " That is, the speed change stage (speed change ratio) is set within a range in which acceleration can be accelerated to "acceleration at the time of re-acceleration" at the time of re-accelerating after the downshift. By controlling in this way, the downshift at the time of decelerating traveling can have a certain regularity. Further, it is possible to provide a predictability of the timing of downshifting. As a result, it is possible to make the running peeling given to the driver at the time of the downshift to be good.

When downshifting is performed at the time of deceleration running on the basis of the "expected vehicle speed", the "current vehicle speed" and the "acceleration at the time of ashes acceleration" as in the above-described respective embodiments, Until it is started, an unavoidable response delay occurs. If the response delay is large, the driver does not match the timing of the downshift which the driver intends or predicts, which may give the driver a sense of incongruity. Therefore, as shown in Fig. 14, for example, the downshift is preceded by using the " predicted vehicle speed " (solid line) read in advance for a predetermined time for the " current vehicle speed " So as to perform the control. The "predicted vehicle speed" can be obtained by multiplying the acceleration (specifically, the deceleration) of the vehicle Ve by the read time previously obtained by, for example, an experiment or a simulation. 14 also shows the current engine speed (broken line) corresponding to the "current vehicle speed" and the predicted engine speed (solid line) corresponding to the "predicted vehicle speed". In this way, by executing the same control as in each of the above-described embodiments based on the previously read vehicle speed, it is possible to solve the problem caused by the response delay of the downshift as described above. As a result, running peeling of the vehicle Ve can be improved.

The deceleration of the vehicle Ve for obtaining the "predicted vehicle speed" can be calculated from the detection data of the output rotation speed sensor 12 and the vehicle speed sensor 13 as described above. Alternatively, it may be obtained from the detection data of the acceleration sensor mounted on the vehicle Ve. Further, it may be calculated based on the detection data of the brake pressure sensor provided in the braking device.

In the above-described control map of Fig. 5, the correlation line between the " accelerating acceleration " and the vehicle speed is linear in the linear function, but it may be nonlinear as shown in Fig. The correlation line between the " acceleration during acceleration " and the vehicle speed is not limited to the linear function as in the above-described embodiment, but may be expressed by, for example, a quadratic function or an exponential function. In such a case, it is also possible to execute the control in each of the above-described embodiments by using the nonlinear control map as shown in Fig.

When the control is executed by using the control map shown in Figs. 5 and 15, there is actually an upper limit to the acceleration that the driver expects or requires at the time of re-acceleration running. When a speed change stage (speed change ratio) for generating an acceleration exceeding the upper limit is set and downshifted, a low speed stage (a large speed change ratio) is selected rather than the driver assumes, which may give the driver a sense of discomfort. Therefore, in the control map of Fig. 5 and Fig. 15, the " accelerating acceleration " which is expected by the driver is substantially unnecessary. Therefore, for example, the control map of Fig. 5 can be set as a control map with " expected upper limit acceleration " set as shown in Fig. By setting the upper limit of the acceleration in consideration of the driver's intention and the expectation value in the control map for obtaining the " acceleration at the time of re-acceleration " in this way, avoiding the setting of the gear range exceeding the driver's expectation as described above The downshift can be appropriately performed.

In the flowchart of Fig. 17, a modification of the control shown in the flowchart of Fig. 2 described above is shown. In the control example shown in the flowchart of Fig. 17, the engine speed is controlled so as to wait for the engine speed to become lower than the predetermined upper limit threshold so as to prevent the engine speed from excessively increasing at the time of downshifting at the time of deceleration running. In the flowchart of Fig. 17, the control contents of steps S11 and S12 are added to the flowchart of Fig. Therefore, in the control example shown in the flowchart of Fig. 17, in the same manner as the control shown in the flowchart of Fig. 2, in step S1 to step S5, the estimated vehicle speed Vexp, the accelerating acceleration Gexp, the outputable acceleration Gabl, (Speed ratio) at which Gabl can be output is calculated. In step S6, it is determined whether or not the vehicle Ve is decelerating. If the vehicle Ve is judged to be negative in the step S6 because it is not in the deceleration running state, this routine is once terminated without performing the subsequent control. On the other hand, if the vehicle Ve is judged to be positive in step S6 because of the deceleration running, the process proceeds to step S7.

In step S7, it is determined whether or not the gear position currently set in the automatic transmission 4 is a higher gear position than the gear position calculated in step S5, that is, whether or not the gear ratio of the current gear position is smaller than the gear ratio of the calculated gear position Is determined. The present speed change stage is slower than the calculated speed change stage, and if the negative determination is made in step S7, this routine is once terminated without performing the subsequent control. On the other hand, if the current gear range is higher than the calculated gear range and the determination in step S7 is positive, the flow advances to step S11.

In step S11, the engine speed Ne1 corresponding to the calculated speed change stage (speed ratio) is calculated. That is, the calculated speed change stage (speed ratio) is set and the estimated engine rotation speed Ne1 is obtained when shifting is performed.

When the engine speed Ne1 is calculated in step S11, it is determined whether or not the engine speed Ne1 is lower than the upper limit threshold value (step S12). The upper limit threshold value in this case is the upper limit value of the engine revolution determined so as to prevent the engine revolution from excessively increasing at the time of downshift at the time of deceleration travel.

If the negative determination is made in step S12 because the engine rotation speed Ne1 is still equal to or higher than the upper limit threshold value, the control in step S12 is repeated without proceeding to the subsequent step. That is, control of this step S12 is repeatedly executed until the engine speed Ne1 becomes lower than the upper limit threshold value.

Then, when the engine speed Ne1 is lower than the upper limit threshold value, if it is determined in step S12 that it is positive, the process proceeds to step S8. In step S8, a downshift is performed in the automatic transmission 4 toward the calculated speed change stage (speed ratio). Then, this routine is once terminated.

By performing the downshift in consideration of the engine speed at the time of the deceleration running, the engine speed rises excessively when the downshift is performed, and it is possible to restrain the driver from feeling uncomfortable. As a result, running peeling of the vehicle Ve at a downshift at the time of deceleration traveling can be improved.

In the above-described embodiment, the " expected vehicle speed " is obtained from the control map shown in Fig. 5, for example. That is, the " expected vehicle speed " is obtained by using the correlation between the " accelerating acceleration " and the vehicle speed. As described above, in the present invention, the " expected vehicle speed " is defined as the target vehicle speed of the driver at the time of accelerating. From such a definition, when the vehicle speed reaches the " expected vehicle speed " at the time of acceleration running, it can be estimated that the acceleration becomes zero and the acceleration is not further accelerated. Therefore, for example, as shown in the time chart of Fig. 18, when the maximum vehicle speed recorded by the vehicle Ve during acceleration running before the present deceleration running just before the current ashes riding is started (i.e., Vehicle speed) can be set as " expected vehicle speed ". The previous acceleration running is an acceleration running performed before starting the current deceleration running from the time when the " expected vehicle speed " is not yet set. For example, if the controller 8 is configured to clear the " expected vehicle speed " when the ignition switch (or the main switch) is turned OFF, the ignition switch of the vehicle Ve is turned ON , Which is an acceleration running to the present.

In the flowchart of Fig. 19, the control example in which the maximum vehicle speed in the past acceleration running is set as the " expected vehicle speed " In the basic control shown in the flowchart of Fig. 2 described above, when it is judged negatively in step S1, the respective previous values of the expected vehicle speed Vexp and the gradient coefficient K are maintained in step S3. On the other hand, in the driving force control by the controller 8, the control shown in the flowchart of Fig. 19 may be executed instead of executing the control of step S3 in the flowchart of Fig.

For example, if it is determined negative at step S1 in the basic control shown in the flowchart of Fig. 2, the flow proceeds to step S21 in the flowchart of Fig. In step S21, it is determined whether or not the vehicle Ve is accelerating. If it is determined that the vehicle Ve is not accelerating and that the vehicle Ve is negative in step S21, the process proceeds to step S22.

In step S22, the respective previous values of the expected vehicle speed Vexp and the gradient coefficient K are maintained. This is the same control as step S3 in the flowchart of Fig. 2 described above. That is, when it is determined in step S1 that the acceleration running of the vehicle Ve has not yet been completed, or that the acceleration running has not yet been performed since the start of the control, the respective previous values of the expected vehicle speed Vexp and the gradient coefficient K Is the expected vehicle speed Vexp and the gradient coefficient K stored when the ignition switch is turned ON for the current running.

Therefore, in this step S22, if the controller 8 has a configuration for clearing the expected vehicle speed Vexp and the gradient coefficient K when the ignition switch is turned OFF, the controller 8 determines whether the ignition switch is ON The respective initial values of the vehicle speed Vexp and the gradient coefficient K are maintained. If the controller 8 is configured to store the expected vehicle speed Vexp and the gradient coefficient K at that time when the ignition switch is turned OFF, the expected vehicle speed Vexp and the gradient coefficient K stored when the ignition switch is turned OFF And is maintained continuously.

When the respective previous values of the expected vehicle speed Vexp and the gradient coefficient K are maintained in the above-described manner at step S22, the process proceeds to step S4 in the flowchart of Fig. 2, and the same control as that described above is executed. On the other hand, when the vehicle Ve is judged to be positive in step S21 because of the acceleration running, the process proceeds to step S23.

In step S23, it is determined whether the current vehicle speed Vcur is greater than the currently set expected vehicle speed Vexp. If the current vehicle speed Vcur is equal to or less than the expected vehicle speed Vexp, if it is determined to be negative in this step S23, the process proceeds to the above-mentioned step S22 and the same control as that described above is executed.

On the other hand, when the current vehicle speed Vcur becomes higher than the expected vehicle speed Vexp, if it is determined to be positive in step S23, the process proceeds to step S24. In step S24, the expected vehicle speed Vexp is updated. In this case, the present vehicle speed Vcur becomes higher than the expected vehicle speed Vexp which was the highest vehicle speed in the past acceleration running, so that the present vehicle speed Vcur becomes the new maximum vehicle speed. Therefore, the new maximum vehicle speed is set as the latest expected vehicle speed Vexp. Further, in this step S24, the previous coefficient is maintained as in the above-mentioned step S22, for example. As described above, in this step S24, the correlation between the vehicle speed and the acceleration in the running data at the time of acceleration running and the correlation line are not directly used, but the expected vehicle speed Vexp is updated. As a result, the gradient coefficient K, which is the slope of the correlation line, is not updated in this step S24, and the previous value is maintained.

When the expected vehicle speed Vexp is updated in step S24 as described above, the process proceeds to step S4 in the flow chart of Fig. 2 in the same manner as in the case where the respective previous values of the expected vehicle speed Vexp and the gradient coefficient K are held in the above-described step S22, The same control as that of the content is executed.

In the control shown in the flowchart of Fig. 19, when updating the " expected vehicle speed ", the " expected vehicle speed " can be easily obtained without performing particularly complicated calculation processing. As a result, the load on the controller 8 can be reduced. Since the opportunity to update the " expected vehicle speed " is formed even during the acceleration running, the update frequency of the " expected vehicle speed "

In the basic control shown in the flowchart of Fig. 2 described above, when the accelerating operation of the vehicle Ve is terminated, if it is determined in step S1 that the accelerating operation is positive, in step S2, based on the traveling data of the vehicle Ve stored during the last accelerating operation , The expected vehicle speed Vexp and the gradient coefficient K are updated. On the other hand, in the driving force control by the controller 8, the control shown in the following flowchart of Fig. 20 may be executed instead of executing the control of step S2 in the flowchart of Fig. 2 described above. That is, in the driving force control by the controller 8, the " expected vehicle speed " can be obtained by the control example shown in the flowchart of Fig.

When the accelerating operation of the vehicle Ve is completed and it is judged positively in step S1 in the basic control shown in the flowchart of Fig. 2, the process proceeds to step S31 in the flowchart of Fig. In step S31, the expected vehicle speed Vexp and the gradient coefficient K are calculated. Calculated based on the running data (vehicle speed at the start of acceleration, maximum acceleration during acceleration, and the like) of the vehicle Ve stored during the acceleration running determined to be completed, as in step S2 in the flowchart of Fig. 2 described above Vexp and the gradient coefficient K are set.

The expected vehicle speed Vexp calculated here can be an average value of the expected vehicle speed Vexp set at the time of re-acceleration running performed a plurality of times in the past. For example, an average value of a plurality of recent expected expected vehicle speeds Vexp including the latest is calculated, and the average value is set as the latest expected vehicle speed Vexp in this step S31.

When the expected vehicle speed Vexp is set in step S31, it is determined whether or not the set expected vehicle speed Vexp is larger than the previous value of the expected vehicle speed Vexp (step S32). The last value of the expected vehicle speed Vexp is the latest expected vehicle speed Vexp updated up to the previous routine. If the expected vehicle speed Vexp set in step S31 is equal to or less than the previous value of the expected vehicle speed Vexp and the determination in step S32 is negative, the process proceeds to step S33.

In step S33, the respective previous values of the expected vehicle speed Vexp and the gradient coefficient K are held. This is the same control as step S3 in the flowchart of Fig. 2 and step S22 in the flowchart of Fig. 19 described above. In this case, it is determined that acceleration running of the vehicle Ve has been completed once. Therefore, the respective previous values of the expected vehicle speed Vexp and the gradient coefficient K in this case are the expected vehicle speed Vexp and the gradient coefficient K that are calculated and stored when the previous acceleration running ends.

On the other hand, when the expected vehicle speed Vexp set in step S31 is greater than the previous value of the expected vehicle speed Vexp, if the determination in step S32 is positive, the process proceeds to step S34. In step S34, the expected vehicle speed Vexp and the gradient coefficient K are updated. That is, the expected vehicle speed Vexp and the gradient coefficient K newly calculated at this time in step S31 are set as the latest expected vehicle speed Vexp and the gradient coefficient K.

When the expected vehicle speed Vexp and the gradient coefficient K are updated in the above-described manner at step S34, similarly to the case where the respective previous values of the expected vehicle speed Vexp and the gradient coefficient K are held at the aforementioned step S33, the routine proceeds to step S4 in the flowchart of Fig. 2 And control similar to that described above is executed. That is, the accelerating acceleration Gexp is calculated on the basis of the respective previous values of the expected vehicle speed Vexp and the gradient coefficient K held in the step S33 or the latest expected vehicle speed Vexp and the gradient coefficient K updated in the step S34.

Also, the ashes acceleration acceleration Gexp calculated here can use the average value of the acceleration acceleration Gexp at the time of re-acceleration set at the time of the ashes running which has been performed a plurality of times in the past, like the expected vehicle speed Vexp. For example, an average value of the acceleration Gexp at the time of the most recent several times of re-acceleration including the latest is calculated, and the average value is set as the latest re-acceleration acceleration Gexp.

Thus, in the control shown in the flowchart of Fig. 20, the expected vehicle speed Vexp updated at least twice after the completion of the acceleration running is set based on the latest expected vehicle speed Vexp and the previously updated expected vehicle speed Vexp. Alternatively, the expected vehicle speed Vexp is set based on the average value of the expected vehicle speed Vexp obtained at the time of the rebuilding which was carried out plural times in the past. Then, based on the thus-set expected vehicle speed Vexp, acceleration acceleration Gexp is set. The accelerating acceleration Gexp in the ashes accelerating can also be set on the basis of the average value of the accelerating acceleration Gexp in the ashes accelerating operation, which was obtained at the time of re-accelerating which has been performed a plurality of times in the past. Therefore, according to the control shown in the flowchart of Fig. 20, the influence of the error of the running data used for calculating the " expected vehicle speed " is suppressed to improve the estimation accuracy of the " expected vehicle speed & .

In the above-described embodiment, the " expected vehicle speed " is obtained from a correlation line as shown in Fig. 4 or a control map as shown in Fig. 5, for example. The correlation line shown in Fig. 4 and the control map shown in Fig. 5 are set on the basis of the traveling data at the time of the past acceleration running. If the past running data used in this case is simply accumulated, the amount of data becomes enormous. If the past driving data is over-emphasized, even if the driving environment or the driving direction is changed, the driving data before the change is applied. As a result, the estimation accuracy of the " expected vehicle speed & May be lowered. Therefore, in the driving force control by the controller 8, the weighting is applied to the running data used for obtaining the " expected vehicle speed ".

The weighting of the running data as described above is carried out by multiplying the past running data by a predetermined weighting coefficient. Alternatively, predetermined running data is selected from the history of all running data and used for calculation of the " expected vehicle speed ". For example, weighting of the running data is performed by multiplying the correlation line shown in Fig. 4 or the past running data used for setting the control map shown in Fig. 5 by the weighting coefficient w (w < 1) . Alternatively, the weighting of the running data can be performed by setting the correlation line shown in Fig. 4 using only the latest running data that has passed a predetermined number of times from the latest.

For example, as shown in the graph of Fig. 21, the point (x ₀ , y ₀ ) plotted on the graph as the predetermined running data and the approximate line obtained from the history of the running data as "y = a × x + b ", the error d of the point (x ₀ , y ₀ ) becomes d = (y ₀ -a x x ₀ -b). Here, the square error (w) × d ² considering the weighting factor w for weighting is (w) × d ² = (w) × (y ₀ -a × x ₀ -b) ² . Therefore, this square error (w) × d ² can be determined by calculating the coefficient a and the coefficient b that is a minimum, the approximate line "y = a × x + b '. The coefficient a and the coefficient b at which such a square error (w) x d ² is minimized are calculated by an ignition formula shown by the following equations (1) and (2), respectively.

In the above equations (1) and (2), let A _n be the term of the sum of x ² , A _n-1 and A _n are represented by the recursion formula as in the following expressions (3) and .

The equation (1) and equation (2) wherein with respect to the sum of x ² in the ignition, adding to the current time value of x ² (x _n ²⁾ to the last time value of the sum (A _{n- 1)} of the total sum By multiplying the weighting coefficient w, the total current time value A _n can be obtained. This is similarly applied to the other sum terms in the ignition formula of the above-mentioned equations (1) and (2). Therefore, regarding the coefficient a and the coefficient b expressed by the above-mentioned equations (1) and (2), if the last value of the total is known, the current time value can also be obtained. Therefore, even if the past history data of the running data is not stored, if the previous value of the total sum is stored, the approximate line " y = a x x + b " can be obtained.

When weighting of the running data is performed with the weighting coefficient w as, for example, " w = 0.7 ", as shown in Fig. 22, the information amount of about 75% . By applying the weighting as described above, it is possible to increase the importance of recent data and to clear past data, for example, which has a lower importance. Further, by setting the weighting coefficient w to a constant value, the change of the ignition formula every time in the above-mentioned ignition formula becomes constant, and as a result, the approximation line "y = a x x + b" . Thus, by weighting the running data as described above, the load of the memory for storing the data and the load during the arithmetic processing can be reduced while securing the constant estimation precision of the "expected vehicle speed" and the "acceleration at the time of acceleration" .

In the control map shown in Fig. 5, the straight line f for estimating the " accelerating acceleration " from the " expected vehicle speed " is defined by the gradient coefficient K. By updating the gradient coefficient K by learning, it is possible to improve the estimation accuracy of the " acceleration at acceleration ". For example, as shown in Fig. 23, when the actual ground acceleration of the vehicle Ve is smaller than the "accelerating acceleration" estimated from the straight line f of the gradient coefficient K, the "expected vehicle speed" , And the gradient coefficient K is learned so that the actual earth acceleration becomes " accelerating acceleration ". In the example shown in Fig. 23, the gradient coefficient K is changed to the gradient coefficient K 'on the side where learning is performed. Further, when the actual earth acceleration is large with respect to the " acceleration during acceleration " estimated from the straight line f of the gradient coefficient K, the gradient coefficient K is changed to become larger on learning. The above learning of the gradient coefficient K can be performed based on the data of the past one time, but the learning value of the gradient coefficient K can be obtained with reference to a plurality of times of data to estimate the " accelerating acceleration " .

In the case of learning the gradient coefficient K as in the embodiment shown in FIG. 23, when the gradient coefficient K is excessive, the estimated value of the " accelerating acceleration " also increases when the deviation between the " expected vehicle speed " It becomes excessive. As a result, a low-speed gear (a large gear ratio) is selected rather than what the driver presumes, and there is a possibility that the driver may feel uncomfortable. Therefore, when learning the gradient coefficient K as described above, the upper limit may be set to the learning value. For example, as shown in Fig. 24, when the actual ground acceleration of the vehicle Ve is greater than the " accelerating acceleration " estimated from the straight line f of the gradient coefficient K, the " expected vehicle speed " , The gradient coefficient K is increased so that the actual earth acceleration becomes " accelerating acceleration ". However, even if the gradient coefficient K is increased up to the gradient coefficient K "of the upper limit, if the actual earth acceleration does not coincide with the estimated " acceleration at the time of ashes acceleration " The expected vehicle speed " is increased to set the straight line f such that the actual ground acceleration becomes the " acceleration at the time of re-acceleration ".

By performing the learning of the gradient coefficient K by setting the upper limit in this manner, it is possible to estimate the " acceleration at the time of ashes acceleration " with high accuracy while avoiding the excessive value of the " acceleration at acceleration "

The control incorporating learning of the gradient coefficient K as described above is executed as shown in the flowchart of Fig. 25, for example. The control shown in the flowchart of Fig. 25 is obtained by replacing step S2 in the basic control shown in the flowchart of Fig. 2 described above with step S41 in the flowchart of Fig. That is, in step S2 described above, the expected vehicle speed Vexp and the gradient coefficient K are updated on the basis of the traveling data stored during the acceleration running. In this step S41, learning of the gradient coefficient K is performed as described above, And the expected vehicle speed Vexp is obtained based on the learning value of the gradient coefficient K. [

When the expected vehicle speed Vexp is updated based on the learning value of the gradient coefficient K as described above, the flow proceeds to step S4. After step S4, the same control as described above is executed.

Claims (6)

A driving force control apparatus for a vehicle (Ve) having an engine (3), a drive wheel (2), and an automatic transmission (4) for transmitting torque between the engine (3) and a drive wheel (2)
(i) controls the driving force of the vehicle Ve based on the vehicle speed of the vehicle Ve and the accelerator opening degree,
(ii) an acceleration characteristic in which the relationship between the acceleration and the vehicle speed is determined in the re-acceleration, and the acceleration in the re-acceleration is used as a control index when the vehicle is decelerating and running,
(iii) obtains acceleration at the time of re-acceleration corresponding to the current vehicle speed on the basis of the traveling data of the vehicle Ve before the decelerated traveling and the stored acceleration characteristics,
(iv) setting a speed ratio of the automatic transmission (4) capable of realizing acceleration at the time of re-acceleration based on a control index that is the acceleration at the time of re-acceleration obtained before starting the re-acceleration running,
(v) estimating an expected vehicle speed desired by the driver at the time of the restart running based on the running data at the time of acceleration running before the deceleration running,
(vi) obtaining the accelerating acceleration corresponding to the current vehicle speed on the basis of the current vehicle speed and the estimated expected vehicle speed,
(vii) a plurality of acceleration characteristic lines, which are determined according to the vehicle speed,
(viii) selecting any one of the acceleration characteristic lines based on the expected vehicle speed,
(ix) determining the acceleration at the time of re-acceleration corresponding to the current vehicle speed on the basis of the current vehicle speed and the expected vehicle speed and the selected acceleration characteristic line
And a controller (8). delete delete 2. The apparatus according to claim 1, wherein the controller (8)
(i) a vehicle speed and an acceleration at the time of starting the rebuilding running,
(ii) update the acceleration characteristic line. 5. The system according to claim 1 or 4, wherein the controller (8)
(i) obtaining the acceleration at the time of the re-acceleration using the average value of the acceleration during the re-acceleration or the average value of the expected vehicle speed in the re-acceleration running performed multiple times in the past,
(ii) the speed ratio of the automatic transmission 4 capable of realizing the obtained acceleration at the time of re-acceleration. 5. The system according to claim 1 or 4, wherein the controller (8)
Is configured to set the maximum vehicle speed recorded by the vehicle (Ve) as the expected vehicle speed before starting the deceleration running from the time when the expected vehicle speed is not set.

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