JP6229702B2 - Driving force control device - Google Patents

Description

  The present invention relates to a driving force control device that controls a driving force of a vehicle by changing an output of a driving force source and a gear ratio of an automatic transmission.

  Patent Document 1 describes a vehicle control device including an engine and an automatic transmission that can be controlled without depending on a driver's accelerator operation. In the control device described in Patent Document 1, a target acceleration after the acceleration of the vehicle is set at the time of accelerator depression for starting or accelerating is set, and the actual acceleration follows the target acceleration. Output is controlled. The target acceleration is obtained on the basis of the history of acceleration data at the time of actual acceleration rising and the intention (driving orientation) of the driver to travel.

  Patent Document 2 discloses a vehicle control for the purpose of improving drivability at the time of reacceleration (for example, acceleration performance according to reacceleration intention) by appropriately setting a gear ratio according to the intention of deceleration. An apparatus is described. In the control device described in Patent Document 2, the gear ratio of the automatic transmission is determined based on the deceleration during deceleration traveling. Specifically, the required drive amount at the time of reacceleration is obtained based on the deceleration during deceleration traveling, and the gear ratio of the automatic transmission that can realize the requested drive amount is obtained. Based on the time integral value of deceleration until the peak value of deceleration during deceleration traveling is obtained after the control start condition for determining the gear ratio is satisfied, the drive request amount at the time of reacceleration is corrected. .

  Patent Document 3 describes a vehicle control device that aims to improve drivability by using behavior characteristics that accurately reflect the traveling environment and driving orientation of the vehicle. In the control device described in Patent Document 3, an index based on the traveling state of the vehicle is obtained, and the traveling characteristics of the vehicle are changed according to the index. When the index is changed, the index is quickly changed in the direction in which the vehicle traveling agility increases, and is slowly changed in the direction in which the vehicle traveling agility decreases.

  Further, Patent Document 4 discloses a shift control device for an automatic transmission for the purpose of realizing stable turning travel by accurately determining the driver's driving orientation and switching the shift schedule accurately. Is described. In the control device described in Patent Document 4, shift control of the automatic transmission is executed according to a preset first shift schedule. Then, when the acceleration integrated value obtained by integrating the absolute value of the acceleration every predetermined period is larger than the reference value, the first shift schedule is switched to the second shift schedule in which a part of the shift line is changed to the high vehicle speed side. . While the turning state of the vehicle is detected, the vehicle acceleration integrated value immediately before the turning state is detected is applied as the vehicle acceleration integrated value.

JP 2009-262838 A JP 2013-185696 A JP 2011-207463 A JP 2004-257435 A

  The control device described in Patent Document 1 is intended to improve the feeling of acceleration of the vehicle in the latter half of the acceleration travel after the acceleration peak value. Therefore, in the control device described in Patent Document 1, the target acceleration is set using the history of acceleration data at the time of acceleration rising. The target acceleration is changed according to the driving orientation of the driver. The driving orientation is switched between a normal mode (normal traveling orientation) and a power mode (sport traveling orientation) based on a switch switching operation or a driver's accelerator operation. In the power mode, a larger target acceleration is set over a longer period than in the normal mode. Therefore, according to the control device described in Patent Document 1, even when the driver's driving orientation changes from the normal mode to the power mode, an appropriate target acceleration that reflects the driving orientation change is set. Thus, it is possible to obtain an appropriate vehicle acceleration performance in the power mode.

  However, in the control by the control device described in the above-mentioned Patent Document 1, a measure for improving the acceleration state in the first half of the accelerated traveling is not considered. In order to improve the acceleration state in the first half of the acceleration travel, for example, before starting the acceleration travel, it is necessary to set in advance an appropriate gear stage or gear ratio considering the subsequent acceleration travel by the automatic transmission. On the other hand, as described in Patent Document 1 described above, when the control is performed based on the target acceleration obtained from the past acceleration history, the latest driving intention and driving orientation of the driver are appropriately reflected in the control. May not be possible. For example, when the driver's driving orientation changes from a sports driving orientation of the vehicle to a fuel economy driving orientation that gives priority to improving the fuel efficiency and efficiency of the vehicle, it is slower than the gear stage (speed ratio) intended by the driver. The side gear (gear ratio) may be set, and as a result, the driver may feel uncomfortable.

  The present invention has been conceived by paying attention to the technical problem described above, and is intended for a vehicle equipped with an automatic transmission. It is an object of the present invention to provide a driving force control device that can re-accelerate a vehicle with a driving force that appropriately reflects driving orientation.

  In order to achieve the above object, the present invention relates to a vehicle driving force including an engine, a driving wheel, and an automatic transmission that transmits torque between the engine and the driving wheel. The driving force control device that controls the driving force includes a controller that controls the driving force, and the controller stores the vehicle speed and acceleration of the vehicle during acceleration traveling before the vehicle travels at a reduced speed. The acceleration history line is calculated using the correlation, and the acceleration history line is updated every time the acceleration travel is performed, and the acceleration vehicle is used as a target vehicle speed when performing the reacceleration after the deceleration travel. Based on the current vehicle speed and the expected vehicle speed, the vehicle is reaccelerated based on the current vehicle speed and the expected vehicle speed. The acceleration at the time of reacceleration as a control index is obtained, and before starting the reacceleration running, the speed ratio of the automatic transmission capable of realizing the acceleration at the time of reacceleration is set based on the acceleration at the time of reacceleration, The vehicle is configured to update the expected vehicle speed when it is determined that the vehicle is traveling steadily with an acceleration within a predetermined acceleration range close to 0 including positive acceleration and negative acceleration. Is a result of a comparison between the steady running vehicle speed when the steady running is determined and the comparison vehicle speed set as a threshold for judging the latest estimation accuracy of the expected vehicle speed. When the vehicle speed is lower than the comparative vehicle speed, the vehicle speed is updated so that the expected vehicle speed set based on the acceleration history line decreases.

  Further, the present invention is characterized in that the comparative vehicle speed is the expected vehicle speed updated last time.

  Further, according to the present invention, the acceleration history line shows a negative correlation, the perceived lower limit acceleration is set as a minimum value at which the driver can perceive the acceleration of the vehicle, and the comparative vehicle speed is on the acceleration history line. The acceleration is the vehicle speed at which the perceived lower limit acceleration is achieved.

  In the present invention, a variation lower limit line is set based on variations in the travel data on the side where both the vehicle speed and the acceleration become smaller than the acceleration history line, and the comparison vehicle speed is equal to the variation lower limit. The vehicle speed is calculated based on the line.

  In the driving force control device according to the present invention, the automatic transmission capable of accelerating the vehicle with the acceleration at the time of reacceleration before the reacceleration running is started at the time of reacceleration after the deceleration running. A gear position (or gear ratio) is set. The acceleration at the time of reacceleration is an acceleration expected by the driver at the time of reacceleration after the deceleration traveling, and is a control index in driving force control at the time of reacceleration. The acceleration at the time of reacceleration is obtained based on the expected vehicle speed estimated as the vehicle speed desired by the driver during the reacceleration running. The expected vehicle speed is obtained by calculating a correlation line or approximate line between the acceleration at the time of reacceleration and the vehicle speed based on the traveling data at the time of previous acceleration traveling. Therefore, the expected vehicle speed is calculated as an estimated value reflecting the driver's intention and driving intention.

  Since the acceleration at the time of reacceleration is obtained based on the expected vehicle speed as described above, the acceleration at the time of reacceleration can be used as a control index for shift control reflecting the driver's intention, driving orientation, and the like. Therefore, at the start of reacceleration after deceleration, the automatic transmission can set a gear ratio that can obtain the driving force necessary for reacceleration. Further, the gear ratio set at that time is a gear ratio that is estimated to be able to accelerate the vehicle at an acceleration intended by the driver or an acceleration requested by the driver.

  Therefore, according to the driving force control apparatus of the present invention, for example, since the downshift during the deceleration traveling is insufficient, the downshift is further performed to compensate for the lack of the driving force during the reacceleration traveling after the deceleration traveling. It is possible to appropriately accelerate the vehicle while avoiding breakage. For this reason, it is possible to suppress the driver from feeling uncomfortable or shock, and to improve the acceleration performance and acceleration feeling of the vehicle.

  In the driving force control apparatus of the present invention, the expected vehicle speed for obtaining the acceleration at the time of reacceleration as described above is updated and set during the steady running of the vehicle in addition to the accelerated running of the vehicle. When the vehicle travels at an accelerated speed, the driver's driving orientation tends to be stronger in a sports driving orientation that prioritizes the power performance of the vehicle than a fuel consumption traveling orientation that prioritizes the fuel efficiency and energy efficiency of the vehicle. On the other hand, for example, during slow deceleration traveling where the negative acceleration of the vehicle, that is, deceleration, is less than a predetermined value, or during steady traveling where almost no acceleration occurs, the driving orientation is more fuel intensive than sports driving. Tend. On the other hand, according to the driving force control apparatus of the present invention, the expected vehicle speed is updated not only when the vehicle travels at an accelerated speed but also when the vehicle travels as described above. Therefore, even when the vehicle travels in a steady state and the driving orientation is predicted to change toward the fuel consumption traveling orientation, the change in the driving orientation can be appropriately reflected in the control.

  Furthermore, in the driving force control apparatus according to the present invention, when the steady running of the vehicle as described above is determined, the latest estimated vehicle speed estimation accuracy is determined. Specifically, the steady traveling vehicle speed and the comparative vehicle speed are compared. When the steady traveling vehicle speed is lower than the comparative vehicle speed, it is determined that the estimation accuracy of the expected vehicle speed is not good, and the expected vehicle speed is reduced and updated. On the other hand, when the steady traveling vehicle speed is equal to or higher than the comparative vehicle speed, it is determined that the estimation accuracy of the expected vehicle speed is good, and the expected vehicle speed is updated without being lowered. That is, the latest expected vehicle speed setting calculated last is maintained. Therefore, according to the driving force control apparatus of the present invention, the expected vehicle speed can be appropriately updated according to the estimation accuracy of the expected vehicle speed. Therefore, the driving force of the vehicle can be controlled by appropriately reflecting the driver's intention and driving intention.

  Moreover, according to the driving force control apparatus of the present invention, the expected vehicle speed that has been updated and set previously is set as the comparative vehicle speed. Therefore, the comparison vehicle speed can be easily set, and the estimation accuracy of the expected vehicle speed can be easily determined.

  Further, according to the driving force control apparatus of the present invention, the vehicle speed at which the acceleration is the perceived lower limit acceleration on the acceleration history line is set as the comparative vehicle speed. Therefore, when the steady traveling vehicle speed is equal to or higher than the comparative vehicle speed, the acceleration on the acceleration history line is equal to or lower than the perceived lower limit acceleration, and the driver is in a traveling state where the driver cannot perceive the acceleration. Therefore, avoiding lowering the expected vehicle speed in a driving state where the driver cannot perceive the acceleration by setting the vehicle speed at which the acceleration is the perceived lower limit acceleration as the comparative vehicle speed as described above. can do. Therefore, the estimation accuracy of the expected vehicle speed can be improved.

  According to the driving force control apparatus of the present invention, the variation lower limit line is set in consideration of the variation in the travel data, and the vehicle speed calculated based on the variation lower limit line is set as the comparison vehicle speed. For example, the virtual expected vehicle speed is calculated using a variation lower limit line instead of the acceleration history line. Then, the virtual expected vehicle speed is set as the comparative vehicle speed. Therefore, when the steady traveling vehicle speed is equal to or higher than the comparative vehicle speed, the traveling state is highly likely to include variation in traveling data. Therefore, setting the vehicle speed calculated in consideration of the variation in the travel data as the comparative vehicle speed as described above avoids erroneous determination of the accuracy of the expected vehicle speed by the travel data within the range of the variation. be able to. Therefore, the estimation accuracy of the expected vehicle speed can be improved.

It is a figure which shows an example of the structure of the vehicle used as the object of control by this invention, and a control system. It is a flowchart for demonstrating an example of basic driving force control by the driving force control apparatus of this invention. It is a figure for demonstrating the correlation of the "acceleration at the time of reacceleration" calculated | required in order to calculate the "expected vehicle speed" and the "acceleration at the time of reacceleration" in the driving force control of this invention, and a vehicle speed. It is a figure for demonstrating the correlation line (approximate line) in the correlation shown in FIG. It is a figure for demonstrating an example of the control map for calculating | requiring "acceleration at the time of reacceleration" in the driving force control of this invention. It is a figure for demonstrating the control which calculates | requires the gear stage (speed ratio) which can output "output possible acceleration" and its output possible acceleration in the driving force control of this invention. It is a block diagram for demonstrating the structure of the controller which performs the driving force control of this invention. It is a figure for demonstrating the behavior (vehicle speed, acceleration, engine speed, etc.) of a vehicle at the time of performing the driving force control of this invention targeting the vehicle carrying a continuously variable transmission. It is a figure for demonstrating the calculation method of the approximate line of driving | running | working data regarding the control which weights with respect to the driving | running | working data for calculating | requiring "expected vehicle speed" and "acceleration at the time of reacceleration." It is a figure for demonstrating the effect of the weighting with respect to said driving | running | working data. It is a flowchart for demonstrating an example of the characteristic driving force control by the driving force control apparatus of this invention. It is a figure for demonstrating the 1st example of the setting method of the "comparison vehicle speed" used as a threshold value by control shown by the flowchart of FIG. It is a figure for demonstrating the 2nd example of the setting method of the "comparison vehicle speed" used as a threshold value by control shown by the flowchart of FIG. FIG. 12 is a diagram for explaining a third example of a method of setting “comparative vehicle speed” used as a threshold value in the control shown in the flowchart of FIG. 11.

  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 an engine and transmitting it to drive wheels. The automatic transmission according to the present invention may be a continuously variable transmission capable of continuously changing a gear ratio, such as a belt type continuously variable transmission or a toroidal continuously variable transmission. The present invention can also be applied to a hybrid vehicle provided with a power split mechanism that combines and splits the power output from the engine and the motor. That is, since the power split mechanism in such a hybrid vehicle functions as a so-called electric continuously variable transmission mechanism, such an electric continuously variable transmission mechanism can also be included in the automatic transmission of the present invention.

  As an example of a vehicle to which the present invention can be applied, FIG. 1 shows the configuration and control system of a vehicle in which an automatic transmission is mounted on the output side of an engine. A vehicle Ve shown in FIG. 1 has a front wheel 1 and a rear wheel 2. In the example shown in FIG. 1, a vehicle Ve is a rear wheel that generates driving force by transmitting power output from an engine (ENG) 3 to a rear wheel 2 via an automatic transmission (AT) 4 and a differential gear 5. It is configured as a driving car. The vehicle Ve to which the present invention can be applied may be a front-wheel drive vehicle that generates power by transmitting the power output from the engine 3 to the front wheels 2. Alternatively, it may be a four-wheel drive vehicle that generates driving force by transmitting power output from the engine 3 to the front wheels 1 and the rear wheels 2, respectively.

  The engine 3 includes, for example, an electronically controlled throttle valve or an electronically controlled fuel injection device, and an airflow sensor that detects 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, for example, 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 an accelerator sensor 9 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 general stepped automatic transmission composed of, for example, a planetary gear mechanism and a clutch / brake mechanism. By controlling the operation of the clutch mechanism and the brake mechanism, the automatic transmission 4 4 is configured so that the gear position (or gear ratio) set in step 4 can be automatically controlled.

  A controller (ECU) 8 for controlling the output of the engine 3 and the shift operation of the automatic transmission 4 is provided. The controller 8 is an electronic control device mainly composed of a microcomputer, for example. The engine 1 is connected to the controller 8 so that communication for control is possible. The automatic transmission 4 is connected to the controller 8 through a hydraulic control device (not shown) so that communication for control is possible. Although FIG. 1 shows an example in which one controller 8 is provided, 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 sensors in each part of the vehicle Ve, information signals from various in-vehicle devices, and the like. For example, the air flow sensor 7 described above, the accelerator sensor 9 that detects the accelerator opening, the brake sensor (or brake switch) 10 that detects the amount of depression of the brake pedal, and the engine speed that detects the speed of the output shaft 3a of the engine 3 Detection signals from a sensor 11, an output rotation speed sensor 12 for detecting the rotation speed of the output shaft 4a of the automatic transmission 4, and a vehicle speed sensor 13 for detecting the rotation speeds of the wheels 1 and 2 to obtain the vehicle speed. Is input to the controller 8. And it is comprised so that it may calculate using the input data, the data memorize | stored previously, etc., and a control command signal may be output based on the calculation result.

  In the vehicle Ve configured as described above, as described above, when the vehicle Ve re-accelerates after traveling at a reduced speed, a downshift may be performed when the driver depresses the accelerator pedal. If the downshift performed at the time of deceleration traveling is not appropriate, the driving force is insufficient at the time of reacceleration traveling, and when the reacceleration traveling is started, the gearshift is further lowered (the gear ratio is increased). Become. As a result, the driver may feel uncomfortable or feel that the acceleration feeling is not good. In addition, the driver's intention and driving intention also vary depending on the individual difference of the driver and the driving environment. On the other hand, if the downshift at the time of deceleration traveling as described above is performed uniformly, there is a possibility that the driving force and acceleration intended by the driver cannot be obtained when reacceleration traveling is started.

  Therefore, the controller 8 is configured to appropriately re-accelerate the vehicle Ve by executing the driving force control of the vehicle Ve while reflecting the driver's intention and driving intention in the control. Specifically, the controller 8 obtains the “acceleration during reacceleration” as a control index when the vehicle Ve decelerates and then reaccelerates, and calculates the “reacceleration time” before starting the reacceleration run. The speed ratio of the automatic transmission 4 capable of realizing “acceleration” is set. The “acceleration at the time of reacceleration” serves as a control index at the time of reacceleration running after decelerating, and is an estimate of the acceleration desired by the driver or the acceleration expected by the driver during the reacceleration running. This “acceleration during re-acceleration” is obtained based on acceleration characteristics and travel data of the vehicle Ve. The acceleration characteristic defines the relationship between the “acceleration during reacceleration” and the vehicle speed, and is stored in advance in the form of, for example, an arithmetic expression or a map. The traveling data of the vehicle Ve is a physical quantity representing the traveling state of the vehicle Ve, such as the vehicle speed, acceleration, the gear ratio of the automatic transmission 4, or the engine speed, and is extracted from the traveling history before the current deceleration traveling. The For example, if the controller 8 clears the travel data when the ignition switch (or the main switch) is turned off, the travel history before the current deceleration travel is the last for the current travel. This is a history of travel data acquired from when the ignition switch of the vehicle Ve is turned ON and the control described below in FIG. 2 is first started to the present.

  More specific control contents executed by the controller 8 are shown below. FIG. 2 is a flowchart for explaining an example of basic control. First, it is determined whether or not the acceleration traveling of the vehicle Ve has ended (step S1). For example, it is possible to determine whether or not the acceleration traveling has ended based on the detection value of the vehicle speed sensor 13 or the longitudinal acceleration sensor (not shown). In step S1, it is determined that “the acceleration of the vehicle Ve has ended” when the acceleration of the vehicle Ve becomes zero after it has been determined that the vehicle Ve has been accelerated. Alternatively, this is a case where the vehicle Ve is subsequently decelerated so that the acceleration of the vehicle Ve becomes 0 or less. Or it is when the brake switch 10 is turned on. Accordingly, in all other cases, a negative determination is made in this step S1. For example, after the start of this control, the vehicle Ve has not been accelerated yet, the vehicle Ve is decelerating, the vehicle Ve is accelerated, or the vehicle Ve is steady. If there is, a negative determination is made in step S1.

  If an affirmative determination is made in step S1 because the acceleration traveling of the vehicle Ve has ended, the process proceeds to step S2. In step S2, the expected vehicle speed Vexp and the gradient coefficient K are calculated and updated. Specifically, travel data of the vehicle Ve (for example, vehicle speed at the start of acceleration, maximum acceleration during acceleration travel, etc.) stored during acceleration travel determined to be finished in step S1 is read, and the travel data is stored in the travel data. Based on this, the expected vehicle speed Vexp and the gradient coefficient K are updated. When the driver operates the vehicle Ve, it can be assumed that the driver is always driving aiming at a predetermined vehicle speed. In the control by the controller 8, the vehicle speed targeted by the driver as described above or the vehicle speed estimated to be desired by the driver is defined as "expected vehicle speed". Generally, under the same driving environment, the “expected vehicle speed” increases when the driver's driving orientation becomes a driving orientation (sport driving orientation) that emphasizes power performance and exercise performance more than usual. On the other hand, if the driver's driving orientation is a driving orientation that emphasizes fuel efficiency and efficiency more than usual (fuel consumption driving orientation), the “expected vehicle speed” decreases. The expected vehicle speed Vexp can be obtained based on the travel history of the vehicle Ve in which data such as the vehicle speed, longitudinal acceleration, lateral acceleration, steering angle, road surface gradient, and vehicle attitude are recorded. As will be described later, the slope coefficient K represents the slope of the correlation line used when obtaining the “expected vehicle speed”. Details of the expected vehicle speed Vexp and the gradient coefficient K will be described later.

  On the other hand, if a negative determination is made in step S1, the process proceeds to step S3. In step S3, the previous values of the expected vehicle speed Vexp and the gradient coefficient K are held. That is, the expected vehicle speed Vexp and the gradient coefficient K that are calculated and stored when the previous acceleration travel ends are held until the current acceleration travel ends. Note that if acceleration traveling has not yet been performed since the start of this control, for example, the expected vehicle speed Vexp and the gradient coefficient K stored when the ignition switch is turned on and this control is first started are stored. Will continue to be retained. In the configuration in which the expected vehicle speed Vexp and the gradient coefficient K are cleared when the ignition switch is turned OFF, the preset initial values are read when the ignition switch is turned ON, and the expected vehicle speed Vexp and the gradient coefficient are read. Stored as K. Therefore, when acceleration traveling has not yet been performed since the start of this control as described above, the initial values of the expected vehicle speed Vexp and the gradient coefficient K are held. In the configuration in which the expected vehicle speed Vexp and the gradient coefficient K at that time are stored when the ignition switch is turned OFF, as described above, when acceleration traveling has not yet been performed, The expected vehicle speed Vexp and the gradient coefficient K stored when the ignition switch is turned off are read and held continuously.

  When the expected vehicle speed Vexp and the gradient coefficient K are updated in the above step S2, or when the previous values of the expected vehicle speed Vexp and the gradient coefficient K are held in the above step S3, the process proceeds to step S4. In step S4, a reacceleration acceleration Gexp is obtained. When the vehicle Ve decelerates without stopping, the vehicle Ve shifts to a state where the vehicle Ve re-accelerates after finishing the decelerating travel. For example, when the vehicle Ve turns in a corner, the vehicle Ve generally enters the corner while decelerating from the front of the corner. In corners, decelerate or turn at a constant speed. And, when escaping from the corner, it re-accelerates. Thus, when the vehicle Ve travels again after decelerating, it can be assumed that the driver accelerates the vehicle Ve toward the expected vehicle speed Vexp. Therefore, if the vehicle speed difference ΔV (ΔV = Vexp−Vcur) between the expected vehicle speed Vexp and the current vehicle speed Vcur is large, the driver requests a large acceleration to reduce the vehicle speed difference ΔV and re-accelerates the vehicle Ve. I can guess it.

Based on the above assumption, in this step S4, the acceleration Gexp at the time of reacceleration is obtained as the acceleration expected by the driver during the reacceleration running from the vehicle speed difference ΔV between the expected vehicle speed Vexp and the current vehicle speed Vcur. For example, as shown in FIGS. 3 and 4, it is known from the results of running experiments and simulations that there is a negative correlation between the “acceleration during reacceleration” and the vehicle speed. When the vehicle speed at the time of starting the reacceleration running is the x axis and the acceleration (maximum ground acceleration) at that time is the y axis, a linear function correlation line (approximate as shown by “y = a · x + b” in FIG. 4) Line). This correlation line can also be obtained for each driver's driving orientation, as indicated by broken lines f ₁ , f ₂ , and f ₃ in FIG.

  As described above, the “expected vehicle speed” is defined as the vehicle speed targeted by the driver during acceleration traveling. Therefore, when the vehicle speed reaches this “expected vehicle speed”, it is unnecessary to further accelerate the vehicle Ve, and as a result, it can be estimated that the acceleration becomes zero. Accordingly, the “expected vehicle speed” can be obtained by calculating the x intercept (−a / b) at which the y-axis acceleration becomes zero in the linear function correlation line as shown in FIG.

  In addition, said ground acceleration is an acceleration which can be calculated | required as a differential value of the detection data of the output rotation speed sensor 12 or the vehicle speed sensor 13, for example. Although the acceleration can be obtained by an acceleration sensor mounted on the vehicle Ve, in that case, noise may be included in the acceleration detection data due to the influence of the attitude of the vehicle Ve or the road surface gradient. Therefore, in this control, the ground acceleration obtained from the rotation speed sensor as described above is used.

  Using the correlation between the “acceleration at the time of reacceleration” and the vehicle speed as described above, the relationship between the “acceleration at the time of reacceleration” and the vehicle speed is determined in advance as the acceleration characteristic of the vehicle Ve and stored in the controller 8. I can leave. By determining such acceleration characteristics as a function of vehicle speed, it is possible to calculate “acceleration during reacceleration” corresponding to the “expected vehicle speed” and “current vehicle speed” as described above.

  Further, “acceleration during reacceleration” corresponding to “expected vehicle speed” and “current vehicle speed” can be obtained from a control map as shown in FIG. 5, for example. That is, using the correlation between the “acceleration at the time of reacceleration” and the vehicle speed obtained from the travel history or travel information at the time of previous acceleration travel, the relationship between the “acceleration at the time of reacceleration” and the vehicle speed in advance. The acceleration characteristic of the vehicle Ve can be determined and stored in the controller 8 as a control map as shown in FIG.

  In FIG. 5, the straight line f corresponds to the above-mentioned correlation line “y = a · x + b”, and shows an acceleration characteristic that defines the relationship between “acceleration during reacceleration” and the vehicle speed. The slope of this straight line f indicates the slope coefficient K. On the straight line f, the vehicle speed at which the ground acceleration becomes 0, that is, the x intercept of the straight line f is the “expected vehicle speed”. Therefore, in FIG. 5, by applying the current vehicle speed Vcur to the straight line f passing through the expected vehicle speed Vexp obtained in step S2 described above and the relational expression indicated by the straight line f and the gradient coefficient K, the acceleration Gexp at the time of re-acceleration Can be requested.

  Further, a plurality of straight lines f can be set for each “expected vehicle speed” as described above or according to driving orientation, as indicated by the straight lines fs and fm in FIG. 5, for example. In that case, a predetermined straight line f is determined from among a plurality of correlation lines as the correlation line based on the travel history during the previous acceleration travel. At the same time, an “expected vehicle speed” is obtained as the x intercept of the straight line f. In this way, the “expected vehicle speed” obtained based on the history during the previous acceleration travel reflects the driving orientation that appeared during the previous acceleration travel. Then, “acceleration at re-acceleration” is obtained based on “expected vehicle speed” obtained as described above and “current vehicle speed” obtained as a detection value of the vehicle speed sensor 13, for example. As shown in FIG. 5, the “acceleration during reacceleration” increases as the difference between the “expected vehicle speed” and the “current vehicle speed” increases. In addition, as the driving orientation is stronger, the straight line fs having the larger “expected vehicle speed” is selected, and the “acceleration at the time of reacceleration” obtained thereby increases. On the contrary, as the driving orientation is more fuel-efficient, the straight line fm having a smaller “expected vehicle speed” is selected, and the “acceleration at the time of reacceleration” obtained thereby becomes smaller.

As described above, when the reacceleration acceleration Gexp is obtained in step S4, the gear position of the automatic transmission 4 capable of realizing the reacceleration acceleration Gexp is obtained (step S5). In other words, an optimum gear stage set by the automatic transmission 4 is required in order for the vehicle Ve to accelerate with the acceleration Gexp during reacceleration. An example of a method for obtaining such a shift stage is shown in FIG. First, outputable acceleration Gabl is set. The output possible acceleration Gabl is expressed as follows: Te _{max is} the maximum output torque of the engine 3, R is the running resistance, W is the vehicle weight, and g is the gear ratio.
Gabl = (Te _max · g−R) / W
It can be calculated from the following formula. As shown in FIG. 6, the outputable acceleration Gabl is calculated for each gear position of the automatic transmission 4.

  FIG. 6 shows an example in which the automatic transmission 4 is an 8-speed stepped transmission. In the example shown in FIG. 6, with respect to the “acceleration at the time of reacceleration” obtained from the “expected vehicle speed” and the “current vehicle speed”, a gear stage that can achieve the “acceleration at the time of reacceleration” (this figure In the example 6, the fastest stage (second speed in the example of FIG. 6) among the second speed, the third speed, the fourth speed, and the fifth speed is selected. That is, in FIG. 6, the acceleration Gexp at the time of reacceleration is represented 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 at the time of re-acceleration is located between the fifth speed outputable acceleration Gabl and the sixth speed outputable acceleration Gabl. This is because, when the engine 3 outputs the maximum torque, if the automatic transmission 4 is set to the sixth speed or higher speed stage (6th speed, 7th speed, 8th speed), the acceleration at the time of reacceleration This means that Gexp cannot be achieved. Therefore, in the example shown in FIG. 6, the fifth highest speed stage among the fifth speed and lower speed stages (from the fifth speed to the first speed) of the automatic transmission 4 that can achieve the acceleration Gexp at the time of reacceleration. Speed is selected.

  When the gear position (speed ratio) of the automatic transmission 4 capable of realizing the reacceleration acceleration Gexp is calculated in step S5, it is determined whether or not the vehicle Ve is traveling at a reduced speed (step S6). For example, it can be determined whether or not the vehicle Ve is traveling at a reduced speed based on the detection value of the vehicle speed sensor 13 or the longitudinal acceleration sensor (not shown), the operation signal of the brake switch 10, and the like. If the vehicle Ve is not traveling at a reduced speed, and if a negative determination is made in step S6, the routine is temporarily terminated without executing the subsequent control.

  On the other hand, when the vehicle Ve is traveling at a reduced speed, if the determination in step S6 is affirmative, the process proceeds to step S7. In step S7, whether or not the gear stage currently set in the automatic transmission 4 is higher than the gear stage calculated in step S5, that is, the gear ratio of the current gear stage is calculated. It is determined whether or not the transmission gear ratio is smaller than the transmission gear ratio. If the current shift speed is lower than the calculated shift speed, and if a negative determination is made in step S7, this routine is temporarily terminated without executing the subsequent control.

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

  A specific configuration of the controller 8 that executes the control during deceleration traveling as described above is shown in the block diagram of FIG. As an example, the controller 8 includes an acceleration calculation unit B1, an expected vehicle speed calculation unit B2, a reacceleration acceleration calculation unit B3, an outputable acceleration calculation unit B4, a target shift speed calculation unit B5, and a shift output determination unit B6. Has been.

  The acceleration calculation unit B1 calculates the acceleration of the vehicle Ve based on the detection data of the output rotation speed sensor 12. The acceleration of the vehicle Ve can also be calculated from the detection data of the vehicle speed sensor 13. The expected vehicle speed calculation unit B2 calculates the expected vehicle speed Vexp based on the acceleration data calculated by the acceleration calculation unit B1 and the detection data of the vehicle speed sensor 13. The reacceleration acceleration calculation unit B3 calculates the reacceleration acceleration Gexp based on the vehicle speed difference ΔV between the expected vehicle speed Vexp calculated by the expected vehicle speed calculation unit B2 and the current vehicle speed Vcur obtained from the detection data of the vehicle speed sensor 13. To do. On the other hand, the outputable acceleration calculating unit B4 calculates the outputable acceleration Gabl for each gear position (or gear ratio) of the automatic transmission 4 based on the detection data of the airflow sensor 7. The target shift speed calculation unit B5 is a target for the automatic transmission 4 based on the reacceleration acceleration Gexp calculated by the reacceleration acceleration calculation unit B3 and the outputable acceleration Gabl calculated by the outputable acceleration calculation unit B4. A gear position (or target gear ratio) is calculated. Then, the shift output determination unit B6 determines the shift command for the automatic transmission 4 based on the target shift stage calculated by the target shift stage calculation unit B5, the detection data of the accelerator sensor 9, and the detection data of the brake switch 10. I do. Specifically, it is determined whether or not it is necessary to perform a downshift on the automatic transmission 4.

  FIG. 6 shows an example in which the automatic transmission 4 is an 8-speed stepped transmission. However, the automatic transmission 4 of the present invention may be a belt-type or toroidal-type continuously variable transmission, or a hybrid. An electric continuously variable transmission mechanism in a vehicle can also be targeted. When the automatic transmission 4 is a continuously variable transmission or an electric continuously variable transmission mechanism of a hybrid vehicle as described above, the gear ratio of the automatic transmission 4 that can realize “acceleration at reacceleration” is calculated, The automatic transmission 4 is controlled based on the calculated gear ratio. For example, as shown in FIG. 8A, a gear ratio γ capable of realizing “acceleration during re-acceleration” is obtained from “current vehicle speed” and “expected vehicle speed”, and an automatic transmission is based on the gear ratio γ. 4 is controlled. FIG. 8B shows the behavior of the engine speed in that case.

  In the embodiment described above, the “expected vehicle speed” is obtained from, for example, the correlation line as shown in FIG. 4 or the control map as shown in FIG. The correlation lines shown in FIG. 4 and the control map shown in FIG. 5 are set on the basis of travel data during past acceleration travel. If past driving data used in that case is simply accumulated, the amount of data becomes enormous. In addition, if past driving data is excessively emphasized, even if the driving environment or driving orientation changes, the driving data before the change will be applied. The estimation accuracy of “acceleration” may decrease. Therefore, in the driving force control by the controller 8, weighting is performed on the travel data used for obtaining the “expected vehicle speed”.

  The weighting of the travel data as described above is performed by multiplying the past travel data by a predetermined weight coefficient. Alternatively, it is carried out by selecting predetermined traveling data from the history of all traveling data and using it for calculating the “expected vehicle speed”. For example, the running data can be weighted by multiplying the past running data used for setting the correlation line shown in FIG. 4 or the control map shown in FIG. 5 by a weighting coefficient w (w <1). it can. Alternatively, the running data can be weighted by setting the correlation line shown in FIG. 4 using only the latest running data that has been traced a predetermined number of times from the latest.

For example, as shown in the graph of FIG. 9, data obtained by plotting predetermined traveling data on the graph is a point (x ₀ , y ₀ ), and an approximate line obtained from the history of traveling data is “y = a · x + b”. Then, the error d of the point (x ₀ , y ₀ ) is
d = (y ₀ −a · x ₀ −b)
It becomes. 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
It becomes. Therefore, by calculating the coefficient a and the coefficient b that minimize the square error (w) · d ² , the approximate line “y = a · x + b” can be obtained. The coefficient a and the coefficient b that minimize the square error (w) · d ² are calculated by the recurrence formulas represented by the following formulas (1) and (2), respectively.

In the above (1) and (2) below, when the term of the sum of ^{x 2} and _{A n, A n-1} and _{A n,} respectively, as follows: (3) and (4) It is expressed by a recurrence formula.

Respect term of (1) and (2) the sum of ^{x 2} in the recurrence formula of Formula, the previous value of the sum _{(A n-1)} the current value of ^{x 2} and _(x ^{n 2)} was added, the sum thereof The current value (A _n ) of the sum can be obtained by multiplying by a weight coefficient w. This also applies to the other summation terms in the recurrence formulas of the above equations (1) and (2). Therefore, for the coefficients a and b represented by the above equations (1) and (2), the current value can be obtained if the previous value of the sum is known. Therefore, even if not all past travel data histories are stored, if the previous value of the sum is stored, the approximate line “y = weighted by the weighting coefficient w from the previous value and the current value of the sum is stored. a · x + b ”can be obtained.

  When the weighting coefficient w as described above is set to, for example, “w = 0.7” and the weighting of the running data is performed, as shown in FIG. Will be occupied. Thus, by performing weighting as described above, it is possible to increase the importance of the most recent data, for example, it is possible to clear past data that has become less important. Also, by making the weighting factor w constant, the change in each recurrence formula as described above becomes constant, and as a result, the approximate line “y = a · x + b "can be easily obtained. Therefore, weighting the driving data as described above ensures a certain estimation accuracy of the “expected vehicle speed” and “acceleration at the time of reacceleration”, and the load of the memory for storing the data and the calculation process. Can reduce the load.

  As described above, in the driving force control by the controller 8, when the reacceleration travel after the deceleration travel is performed, the speed ratio that enables the acceleration travel with the “acceleration during reacceleration” is set before the reacceleration travel is started. Thus, the shift control of the automatic transmission 4 can be completed. In addition, by obtaining the “acceleration at the time of reacceleration” based on the “expected vehicle speed” as described above, the “acceleration at the time of reacceleration” is determined as a control index for shift control that reflects the driver's intention and driving orientation. can do. Therefore, at the start of reacceleration running after deceleration running, the automatic transmission 4 can set a gear ratio capable of obtaining a driving force necessary for reacceleration in advance. Further, the gear ratio set at that time is a gear ratio that is estimated to be able to accelerate the vehicle at an acceleration intended by the driver or an acceleration requested by the driver.

  For example, when the vehicle Ve turns in a corner, the vehicle Ve re-accelerates in the exit stage from the corner in advance during the deceleration travel of the vehicle Ve from the corner entry stage to the corner turning stage. The automatic transmission 4 can be downshifted to a gear ratio that is suitable at times, that is, a gear ratio that can realize “acceleration during reacceleration”. Therefore, when the vehicle Ve enters the corner and makes a turn, the vehicle Ve can be appropriately decelerated and a stable turn can be performed while maintaining a state where a large driving force can be obtained. When the vehicle Ve escapes from the corner and starts reacceleration running, the downshift has already been completed to a state where sufficient driving force can be obtained as described above.

  Therefore, according to the driving force control by the controller 8, since the downshift at the time of the deceleration traveling is insufficient, the downshift is further performed to compensate for the lack of the driving force at the time of the reacceleration traveling after the deceleration traveling. By avoiding this, the vehicle can be appropriately accelerated. Therefore, it is possible to suppress the driver from feeling uncomfortable or shock, and to improve the acceleration performance and acceleration feeling of the vehicle Ve.

  Further, in the driving force control by the controller 8, the “expected vehicle speed” is updated every time acceleration traveling is performed. By updating the “expected vehicle speed” in this way, the latest driving orientation of the driver can be reflected in the control. For example, when the driver's driving orientation changes from fuel-efficient driving orientation to sports driving orientation, the “expected vehicle speed” is updated to an increasing side, and as a result, the automatic transmission 4 has a large shift on the lower speed side. The ratio is easily set. Therefore, in the subsequent reacceleration running, a larger driving force can be generated to enable a strong acceleration running, and the vehicle Ve is appropriately reflected by reflecting the change in the driving orientation to the sports driving orientation as described above. Can be accelerated.

  By the way, if the “expected vehicle speed” is updated only during acceleration traveling as described above, in most cases, it is updated to an increasing side (that is, a sport driving-oriented side) and decreased (that is, a fuel consumption traveling). The frequency of updating to the intended side) will be reduced. As a result, for example, when the driver's driving orientation is reduced from a sports driving orientation to a normal driving orientation, or when the driver's driving orientation is reduced from a normal driving orientation to a fuel consumption driving orientation, the driver is re-accelerated during the subsequent reacceleration driving However, there is a possibility that a larger gear ratio on the low speed side is set than intended.

  Therefore, the controller 8 is configured to update the “expected vehicle speed” even when it is estimated that the driving orientation is reduced to the fuel consumption traveling orientation and it is determined that the driving orientation is reduced to the fuel consumption traveling orientation. Yes. Specifically, in the driving force control by the controller 8, in addition to the acceleration running as described above, the negative acceleration, that is, the deceleration, in which the deceleration is smaller than a predetermined value, or the steady running in which almost no acceleration occurs. Sometimes updated to the side where the “expected vehicle speed” decreases. For example, the “expected vehicle speed” is reduced and updated so as to be a value set in advance assuming that the driving orientation is normal driving orientation. Alternatively, the “expected vehicle speed” is decreased and updated so as to be a value set in advance assuming that the driving orientation is fuel consumption traveling orientation. In the case of reducing the “expected vehicle speed” as described above, for example, according to a steady traveling vehicle speed described later, an “expected vehicle speed” set assuming normal driving intention and a fuel consumption driving intention set. The “expected vehicle speed” may be appropriately selected.

  The slow deceleration traveling is a traveling state in which, for example, the vehicle Ve slowly decelerates when coasting. Specifically, the slow deceleration traveling is a state in which the vehicle Ve decelerates at a deceleration within a deceleration range (determination area) lower than a predetermined deceleration, or a vehicle decelerates from a predetermined deceleration on the negative acceleration side. Is a traveling state in which the vehicle decelerates at a deceleration within a determination region close to zero. This slow deceleration traveling is defined in order to distinguish from the state where the vehicle Ve travels at a reduced speed by a braking operation based on the clear intention of the driver. For example, when the vehicle Ve continues to decelerate at a deceleration within a deceleration range (determination area) lower than a predetermined deceleration as described above, or when the vehicle is When the state where the vehicle is decelerated at a deceleration in the determination region closer to 0 than the predetermined deceleration on the negative acceleration side continues for a predetermined time or more, it is determined that the traveling state of the vehicle Ve is the slow deceleration traveling. .

  The steady running is a running state in which almost no acceleration is generated, and the vehicle Ve travels at a constant speed or almost a constant speed with an acceleration within a predetermined acceleration range including an acceleration larger than 0 and an acceleration smaller than 0. State. For example, when the vehicle Ve travels at a substantially constant speed within a predetermined acceleration range including 0 as described above for a predetermined time or more, or when the vehicle Ve has an acceleration greater than 0 and 0 When the vehicle travels at a constant speed or at a substantially constant speed within a predetermined acceleration range including a smaller acceleration for a predetermined time or more, the vehicle Ve is determined to be in a steady state.

  Note that the control executed by the controller 8 is defined as steady running including the slow deceleration running described above. That is, in this control, the vehicle Ve is traveling at a steady acceleration within a predetermined acceleration range close to 0 including positive acceleration and negative acceleration, including the above-described slow deceleration traveling state. It is defined as

  When the vehicle Ve is traveling as described above, it can be estimated that the driver does not require further acceleration or does not require a large driving force. Therefore, it can be estimated that the driving orientation of the driver has changed to the fuel-efficient driving orientation side. For this reason, in the driving force control by the controller 8, when the above-described steady traveling is determined, the “expected vehicle speed” is decreased and updated. By reducing the “expected vehicle speed”, the automatic transmission 4 is more likely to set a gear ratio that places greater emphasis on fuel efficiency and energy efficiency than the driving force, and it is difficult to set a large gear ratio on the low speed stage side. . As a result, during the subsequent reacceleration running, smooth acceleration running with little change in driving force becomes possible.

  As described above, according to the driving force control by the controller 8, not only when the vehicle Ve travels at an accelerated speed but also when the vehicle Ve travels at a steady state as described above, the “expected vehicle speed” is updated and set. . Therefore, even if the driver's driving orientation changes between a sports driving orientation and a fuel consumption driving orientation, the “expected vehicle speed” corresponding to the latest driving orientation can be set each time.

  Further, the controller 8 sets an appropriate “expected vehicle speed” even when the driving orientation decreases toward the fuel consumption driving orientation, and the driving force reflecting the driver's intention and driving orientation more accurately. It is comprised so that control can be performed. As described above, in the driving force control by the controller 8, the “expected vehicle speed” is decreased when it is estimated that the driving direction is reduced to the fuel consumption driving direction side. However, when the decline in driving orientation is estimated, if the “expected vehicle speed” is reduced uniformly, the “expected vehicle speed” may be reduced even though the driving orientation does not actually decrease. is there. For example, when the vehicle Ve is traveling at a vehicle speed close to the “expected vehicle speed” that has been set in the past, as a result of reaching the vehicle speed desired by the driver, the vehicle Ve is not accelerated or decelerated. There is a possibility. Therefore, even if the vehicle Ve travels as described above, the driving orientation may not be reduced. Therefore, when the controller 8 estimates a decrease in driving orientation, the controller 8 does not uniformly decrease the “expected vehicle speed”, but decreases the “expected vehicle speed” according to the traveling state of the vehicle Ve in that case. It is configured to determine whether or not.

  An example of the control executed by the controller 8 to cope with the situation where the driving orientation is reduced as described above is shown in FIG. The control shown in the flowchart of FIG. 11 is executed in place of step S3 in the flowchart of FIG. 2 when a negative determination is made in step S1 in the flowchart of FIG. First, it is determined whether or not the traveling state of the vehicle Ve is steady traveling (step S101). Specifically, when the vehicle Ve is traveling steadily, it is estimated that the driving orientation has decreased to the fuel consumption traveling-oriented side, and it is determined that the expected vehicle speed Vexp is being reduced.

  Therefore, when the traveling state of the vehicle Ve is not the steady traveling as described above, it is determined that the expected vehicle speed Vexp is not reduced. On the other hand, when the traveling state of the vehicle Ve is steady traveling as described above, it is determined that the expected vehicle speed Vexp is reduced.

  If it is determined in step S101 that the traveling state of the vehicle Ve is not steady traveling, and the determination is negative, the process proceeds to step S102. In step S102, the previous values of the expected vehicle speed Vexp and the gradient coefficient K are held. This is the same control content as step S3 in the flowchart of FIG. Thereafter, the process proceeds to step S4 in the flowchart of FIG. 2, and the same control as described above is executed.

  On the other hand, if it is determined affirmative in step S101 because the traveling state of the vehicle Ve is determined to be steady traveling, the process proceeds to step S103 and step S104. In step S103, the steady traveling vehicle speed is obtained. The steady traveling vehicle speed is a vehicle speed detected when it is determined that the vehicle Ve is traveling as described above.

  In step S104, the expected vehicle speed Vexp is calculated as before. For example, the expected vehicle speed Vexp is calculated using travel data acquired during acceleration travel from when the main switch (or the ignition switch) of the vehicle Ve is turned on to the present. The detailed calculation method of the expected vehicle speed Vexp is as described above.

  When the steady traveling vehicle speed and the expected vehicle speed Vexp are obtained, it is determined whether or not the steady traveling vehicle speed is equal to or higher than the comparative vehicle speed (step S105). The comparative vehicle speed is a threshold value for determining the estimation accuracy of the latest expected vehicle speed Vexp. Specifically, the comparative vehicle speed is set as a threshold value for determining whether or not the expected vehicle speed Vexp should be reduced under the situation where the vehicle Ve is traveling steadily. This comparative vehicle speed can be set by a plurality of methods described below.

  For example, as shown in FIG. 12, the “expected vehicle speed Vexp that has been set based on the acceleration history line”, that is, the expected vehicle speed Vexp that was updated last time can be set as the comparative vehicle speed. The acceleration history line is an approximate line (that is, the correlation line described above) calculated using the traveling data as described above. As described above, when the vehicle Ve is traveling at a steady traveling vehicle speed close to the expected vehicle speed Vexp, there is a possibility that the vehicle Ve is traveling steady as a result of reaching the vehicle speed desired by the driver. In particular, when the vehicle Ve decelerates from a vehicle speed higher than the expected vehicle speed Vexp and then enters a state of steady running at a steady running vehicle speed close to the expected vehicle speed Vexp, it can be estimated that there is a high possibility that the driving orientation is not lowered. . Therefore, in the example shown in FIG. 12, when the steady traveling vehicle speed is equal to or higher than the expected vehicle speed Vexp, that is, equal to or higher than the comparative vehicle speed, it is determined that the expected vehicle speed Vexp should not be reduced.

  Further, as shown in FIG. 13, the “vehicle speed at which the acceleration becomes the perceived lower limit acceleration on the acceleration history line” can be set as the comparative vehicle speed. The perceived lower limit acceleration is set in advance as the minimum acceleration that the driver can perceive. This perceptual lower limit acceleration can be set based on the results of running experiments and simulations. For example, it can be set using the concept of Weber's law. According to Weber's law, “stimulus discrimination threshold (ΔX) changes in proportion to the intensity of the original stimulus (X) (ΔX / X = const)”. If “X” in this Weber's law is the vehicle speed, by specifying the “const” part by running experiments or simulations, the minimum amount of change in vehicle speed that the driver can feel as “ΔX”, that is, The minimum acceleration that the driver can perceive can be estimated.

  By setting the perceived lower limit acceleration as described above, in the example shown in FIG. 13, “the vehicle speed at which the acceleration becomes the perceived lower limit acceleration on the acceleration history line” is set as the comparative vehicle speed. Therefore, when the steady traveling vehicle speed is equal to or higher than the comparative vehicle speed, it is determined that the driver cannot perceive the acceleration of the vehicle Ve. Therefore, in the example shown in FIG. 13, in order to avoid erroneous determination in a region where the driver cannot perceive acceleration, when the steady traveling vehicle speed is equal to or higher than the comparison vehicle speed, the expected vehicle speed Vexp is It is judged that it should not be lowered.

  Further, as shown in FIG. 14, among the variation upper limit line and the variation lower limit line set in consideration of the variation of the travel data with respect to the acceleration history line, the “vehicle speed calculated based on the variation lower limit line” is This comparison vehicle speed can be set. The variation upper limit line is set by estimating the upper variation of the travel data, and is set as a straight line away from the acceleration history line by a predetermined distance in the direction in which the vehicle speed and acceleration are both increased. The variation on the upper side of the travel data is a variation on the side where both the vehicle speed and the acceleration in the travel data increase with respect to the acceleration history line. The variation lower limit line is set by estimating the lower variation of the travel data, and is set as a straight line separated from the acceleration history line by a predetermined distance in a direction in which both the vehicle speed and the acceleration are reduced. The variation on the lower side of the travel data is a variation on the side where both the vehicle speed and the acceleration in the travel data become smaller than the acceleration history line. Further, the predetermined distance can be set based on the results of a running experiment or simulation. The “vehicle speed calculated based on the variation lower limit line” is the virtual expected vehicle speed Vexp calculated from the above-described variation lower limit line in the same manner as the normal expected vehicle speed Vexp calculated from the acceleration history line. .

  In the example shown in FIG. 14, by setting the range of variation as described above and calculating the virtual expected vehicle speed Vexp based on the variation lower limit line, the “vehicle speed calculated based on the variation lower limit line” is compared. Set as vehicle speed. Therefore, when the vehicle speed is equal to or higher than the comparative vehicle speed, it is determined that the variation in travel data is large. Therefore, in the example shown in FIG. 14, in order to avoid erroneous determination in an area where the variation in travel data is large, the expected vehicle speed Vexp is reduced when the steady travel vehicle speed is equal to or higher than the comparison vehicle speed. Judged not to be.

  Therefore, if the steady traveling vehicle speed is lower than the comparative vehicle speed set as described above, and if a negative determination is made in step S105, the process proceeds to step S106. In step S106, the expected vehicle speed Vexp is updated so as to decrease. When the steady traveling vehicle speed is lower than the comparative vehicle speed, it can be determined that the driving orientation has decreased to the fuel consumption traveling orientation side with a constant estimation accuracy. Therefore, in this step S106, as described above, the expected vehicle speed Vexp is updated to the side where it decreases. Thereafter, the process proceeds to step S4 in the flowchart of FIG. 2, and the same control as described above is executed.

  On the other hand, if the steady traveling vehicle speed is equal to or higher than the comparative vehicle speed set as described above, and if a positive determination is made in step S105, the process proceeds to step S107. In step S107, the previous values of the expected vehicle speed Vexp and the gradient coefficient K are held. This is the same control content as step S3 in the flowchart of FIG. 2 and step S102 in the flowchart of FIG. As described above, when the steady traveling vehicle speed is equal to or higher than the comparative vehicle speed, it is determined that the expected vehicle speed Vexp should not be decreased. Therefore, in this step S107, the expected vehicle speed Vexp is not lowered, but the previous value of the expected vehicle speed Vexp that has been updated last time and set from before is held. Thereafter, the process proceeds to step S4 in the flowchart of FIG. 2, and the same control as described above is executed.

  As described above, in the driving force control by the controller 8, when the steady travel of the vehicle Ve as described above is determined, the estimation accuracy of the latest expected vehicle speed Vexp is determined. That is, the steady traveling vehicle speed and the comparative vehicle speed are compared. When the steady traveling vehicle speed is lower than the comparative vehicle speed, it is determined that the estimation accuracy of the expected vehicle speed Vexp is not good, and the expected vehicle speed Vexp is reduced and updated. On the other hand, when the steady traveling vehicle speed is equal to or higher than the comparative vehicle speed, it is determined that the estimation accuracy of the expected vehicle speed Vexp is good, and the previous value of the expected vehicle speed Vexp is held without being lowered. That is, the latest expected vehicle speed Vexp calculated last is maintained. Therefore, according to the driving force control by the controller 8, the expected vehicle speed Vexp can be appropriately updated according to the estimation accuracy of the expected vehicle speed Vexp. Therefore, the driving force of the vehicle Ve can be controlled by appropriately reflecting the driver's intention and driving intention.

  In the specific example described above, the “acceleration history line” is a straight line, but the “acceleration history line” may be a curve. For example, the “acceleration history line” can be obtained as an approximate curve of past travel data. Further, in the above-described specific example, the “acceleration history line” is described as a diagram shown on the graph. However, the “acceleration history line”, a correlation line (straight line f) between the vehicle speed and acceleration, and the like Can also be used in the form of a function, equation or correlation equation representing a diagram.

  DESCRIPTION OF SYMBOLS 1 ... Front wheel, 2 ... Rear wheel (drive wheel), 3 ... Engine, 4 ... Automatic transmission, 6 ... Electronic throttle valve, 7 ... Air flow sensor, 8 ... Controller (ECU), 9 ... Accelerator sensor, 10 ... Brake sensor (Brake switch), 11 ... engine speed sensor, 12 ... output speed sensor, 13 ... vehicle speed sensor, Ve ... vehicle.

Claims (4)

In a driving force control device that controls the driving force of a vehicle including an engine, driving wheels, and an automatic transmission that transmits torque between the engine and the driving wheels based on a vehicle speed and an accelerator opening,
A controller for controlling the driving force;
The controller is
An acceleration history line is calculated using a correlation of travel data storing vehicle speed and acceleration of the vehicle at the time of acceleration traveling before the vehicle decelerates, and the acceleration history line is calculated each time the acceleration traveling is performed. Updated,
Based on the acceleration history line, set an expected vehicle speed that is estimated to be desired by the driver when the reacceleration is performed, as a target vehicle speed when performing the reacceleration after the decelerating travel,
Based on the current vehicle speed and the expected vehicle speed, a re-acceleration acceleration is obtained as a control index when the re-acceleration travels.
Before starting the reacceleration running, set the gear ratio of the automatic transmission that can realize the acceleration at the time of reacceleration based on the acceleration at the time of reacceleration,
The vehicle is configured to update the expected vehicle speed when it is determined that the vehicle is traveling steadily at an acceleration within a predetermined acceleration range close to 0 including positive acceleration and negative acceleration,
The expected vehicle speed is
As a result of comparing the steady running vehicle speed when the steady running is determined and the comparison vehicle speed set as a threshold for judging the latest estimation accuracy of the expected vehicle speed, the vehicle speed during the steady running is compared with the comparison. When the vehicle speed is lower than the vehicle speed, the driving force control device is updated so that the expected vehicle speed set based on the acceleration history line decreases. The driving force control apparatus according to claim 1,
The comparative vehicle speed is
A driving force control apparatus characterized by being the expected vehicle speed updated last time. The driving force control apparatus according to claim 1,
The acceleration history line shows a negative correlation;
The minimum perceived acceleration is set as the minimum value by which the driver can perceive the acceleration of the vehicle,
The comparative vehicle speed is
The driving force control apparatus characterized in that the acceleration is the vehicle speed at which the acceleration becomes the perceived lower limit acceleration on the acceleration history line. The driving force control apparatus according to claim 1,
A variation lower limit line is set based on variation in the travel data on the side where both the vehicle speed and the acceleration become smaller with respect to the acceleration history line,
The comparative vehicle speed is
A driving force control device characterized in that the vehicle speed is calculated based on the variation lower limit line.

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