JP2017150650A - Drive force control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a vehicle which sets a proper gear change stage reflecting a purpose and a drive intention of a driver, and can re-accelerate a vehicle for traveling.SOLUTION: A drive force control device for controlling a drive force of a vehicle calculates an approximate linear line indicating a correlation between a vehicle speed and acceleration at acceleration traveling, sets an expected vehicle speed when a vehicle travels at re-acceleration on the basis of the approximate linear line as a target vehicle speed at the re-acceleration traveling after the vehicle travels at deceleration, acquires acceleration at the re-acceleration as a control index when the vehicle travels at the re-acceleration on the basis of a current vehicle speed and the expected vehicle speed, performs a downshift by setting a gear change ratio of an automatic transmission which can obtain the acceleration at the re-acceleration on the basis of the acceleration at the re-acceleration before the re-acceleration traveling is started, and changes the approximate linear line so that a difference between a maximum value and a minimum value of an engine rotation number after the execution of the downshift reaches a prescribed value or smaller (steps S106, S107).SELECTED DRAWING: Figure 14

Description

  The present invention relates to a driving force control apparatus that controls a driving force of a vehicle by changing a gear ratio of an automatic transmission during deceleration traveling.

  Patent Document 1 describes an invention relating to a vehicle driving force control device that executes deceleration assist control including control for prohibiting upshifting when the accelerator is suddenly closed and control for downshifting when suddenly braking. The driving force control apparatus described in Patent Document 1 is configured to determine the conditions for deceleration assist control as described above based on the traveling environment and traveling state of the vehicle. For example, whether or not to execute the deceleration assist control and the control level for executing the deceleration assist control are determined in accordance with the front inter-vehicle distance, the road surface gradient, or the driving orientation of the driver. And this patent document 1 describes the example of control which makes it possible to downshift to a lower speed stage when the driver's driving orientation is sports driving orientation at the time of execution of the deceleration assist control. . Sports travel orientation is driving orientation that places importance on the power performance of the vehicle and requires quick response of the vehicle to the driving operation.

  Patent Document 2 describes a driver orientation determination device for the purpose of more accurately determining a driver's driving orientation. In the device described in Patent Document 2, when the driver's driving orientation is sports driving orientation, the driving orientation is difficult to be reflected in the driving operation or the vehicle situation, and “the current road condition is It is preset that the vehicle is a road for which turning determination of the vehicle is not established. And the apparatus described in this patent document 2 is that even if the driving orientation up to the previous determination is a sports driving orientation and the current driving orientation is changed from a sports driving orientation to a normal driving orientation, When it is determined that the road condition is a road where the vehicle turning determination is not established, the current driving orientation remains the sports driving orientation and is not changed.

  Further, Patent Document 3 describes a vehicle control device for realizing the vehicle power performance required by the driver during cornering. The control device described in Patent Document 2 is a control device that controls shift of an automatic transmission based on information from a navigation device and driving orientation. And it is comprised so that a driver | operator's driving | operation orientation may be determined at the time of cornering when another vehicle does not exist ahead of the own vehicle, or when the distance between other vehicles is a predetermined distance or more.

JP 2007-170444 A JP 2007-16826 A JP 2005-98364 A

  As described above, in the control device described in Patent Document 1, the driving orientation of the driver is estimated when the vehicle travels. When the driving orientation is sports driving orientation, for example, when the vehicle is decelerated before a corner or an intersection, it is downshifted to a lower speed than when it is not sports driving orientation. By performing a downshift at the time of deceleration, it is possible to improve acceleration performance when the vehicle is reaccelerated after braking.

  On the other hand, the control device described in the above-mentioned Patent Document 1 is configured to downshift by uniformly setting the gear position depending on whether or not the driver's driving orientation is sports driving orientation at the time of deceleration before a corner or an intersection. Is done. In addition, since the driving orientation is a value obtained by estimation, it inevitably includes individual differences of drivers and estimation errors. In particular, when the number of samples of data acquired to estimate the driving orientation is small, or when the driving orientation is actually changed, or when the driving orientation is estimated immediately after the transition, There is a possibility that the estimation error of orientation is increased. If the estimated driving orientation is not appropriate, the gear stage or gear ratio set after the downshift may not be appropriate. For example, if the downshift is insufficient, a further downshift may be performed when the driver depresses the accelerator pedal in order to finish turning at a corner and accelerate. That is, the driving force actually generated may be insufficient with respect to the required driving force intended by the driver. As a result, the driver may feel uncomfortable or may feel that acceleration performance and acceleration feeling are not good.

  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 the intention and driving orientation.

  In order to achieve the above object, the present invention controls an engine mounted on a vehicle, drive wheels, an automatic transmission that transmits torque between the engine and drive wheels, and a drive force of the vehicle. The controller calculates a straight line representing a correlation between the vehicle speed and acceleration of the vehicle at the time of acceleration traveling before the vehicle decelerates and travels at a reduced speed. As a target vehicle speed when performing reacceleration later, an expected vehicle speed estimated to be desired by the driver when performing the reacceleration based on the approximate straight line is set.

  Based on the current vehicle speed and the expected vehicle speed, a reacceleration acceleration is obtained as a control index for the reacceleration running, and before the reacceleration running is started, the reacceleration time is based on the reacceleration acceleration. A downshift is performed by setting a gear ratio of the automatic transmission capable of realizing acceleration, and a maximum value and a minimum value of the engine speed after the downshift determined according to the vehicle speed before the downshift starts The approximate straight line is changed or held such that the difference between and is less than or equal to a predetermined value.

  Further, according to the present invention, the controller changes the approximate straight line by changing the slope of the approximate straight line, sets the median value of the tilt at which the difference is equal to or smaller than the predetermined value, and the difference is set. Is set to a region defining a straight line group of the approximate lines that are changed so as to be less than or equal to the predetermined value, the current approximate line is outside the region, and the slope of the current approximate line is the center If smaller than the value, the current approximate straight line is changed to a straight line having the smallest slope in the area, the current approximate straight line is outside the area, and the current approximate straight line slope is the center. If the value is equal to or greater than the value, the current approximate straight line is changed to a straight line having the maximum inclination in the region.

  In the present invention, the controller changes or holds the approximate straight line when the number of times of the acceleration traveling from the time the main switch of the vehicle is turned on until the present is less than a predetermined number of times. It is characterized by executing control.

  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 an approximate straight line between the acceleration at the time of reacceleration and the vehicle speed based on the travel data at the time of previous acceleration travel. 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.

  Further, in the driving force control device of the present invention, when downshift is executed based on the acceleration at the time of reacceleration as described above, the difference between the maximum value and the minimum value of the engine speed after downshift is a predetermined value. The approximate straight line for obtaining the acceleration at the time of reacceleration is changed or held so as to be as follows. That is, the downshift is executed so that the engine speed after the downshift is aligned regardless of the vehicle speed when the downshift is executed. Therefore, even when the number of travel data samples for calculating the approximate straight line is not sufficient or immediately after the driver's driving orientation changes, the variation in engine speed after downshifting becomes large. A situation in which the driver feels uncomfortable can be suppressed. That is, the drivability of the vehicle 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 the basic 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 straight 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 straight 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. FIG. 3 is a diagram for explaining a state in which an inclination of an approximate straight line of travel data is not appropriate when the number of travel data samples is not sufficient when executing the basic control shown in the flowchart of FIG. 2. FIG. 12 is a diagram for explaining a downshift point and an engine speed region for each vehicle speed that are obtained when the slope of the approximate straight line of the travel data shown in FIG. 11 is not appropriate. FIG. 3 is a diagram for explaining a state in which an inclination of an approximate straight line of travel data is not appropriate immediately after the driver's driving orientation is changed when performing the basic control shown in the flowchart of FIG. 2. It is a flowchart for demonstrating an example of the characteristic control by the driving force control apparatus of this invention. FIG. 15 is a diagram for describing a difference in an engine speed region for each vehicle speed considered when executing the characteristic control shown in the flowchart of FIG. 14. It is a figure for demonstrating the inclination of the approximate line considered when performing the characteristic control shown by the flowchart of FIG. It is a figure for demonstrating the approximate straight line of the suitable inclination considered when performing characteristic control shown by the flowchart of FIG. It is a figure for demonstrating the tolerance | permissible_range for obtaining the approximate straight line of the suitable inclination considered when performing characteristic control shown with the flowchart of FIG. It is a figure for demonstrating an example of the approximate line changed when the characteristic control shown by the flowchart of FIG. 14 is performed. It is a figure for demonstrating the other example of the approximate line changed when the characteristic control shown by the flowchart of FIG. 14 is performed.

  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. Or it is a case where it shifts to the deceleration driving | running | working where 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". For example, under the same driving environment, the “expected vehicle speed” increases if the driving orientation of the driver becomes a driving orientation (sport driving orientation) that emphasizes power performance and exercise performance 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 FIG. 3 and FIG. 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) Straight 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 maximum torque is output by the engine 3 and 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, when the current shift speed is higher than the calculated shift speed, if the determination in step S7 is affirmative, the process proceeds to step S8, toward the calculated shift speed. A downshift is performed by the automatic 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 straight 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, the approximate straight line “y = a · x + b” can be obtained by calculating the coefficient a and the coefficient b that minimize the square error (w) · d ² . 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, an approximate straight 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 straight 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, in the driving force control by the controller 8, as described above, in order to reflect the driving orientation of the driver, the “expectation” is performed by using the traveling history in the past acceleration traveling, in particular, a plurality of traveling data in the acceleration traveling. "Vehicle speed" and "Acceleration during re-acceleration" are estimated. Therefore, when the number of samples of travel data is not sufficient, the estimation accuracy of “expected vehicle speed” and “acceleration during reacceleration” may be reduced. For example, as shown in FIG. 11, the approximate straight line obtained from the travel data history shown in FIG. 9 is essentially an approximate straight line Lr1 that appropriately reflects the driver's driving orientation (estimated with high accuracy). On the other hand, there is a possibility of being obtained as an approximate straight line Lw1 having a greatly different inclination. If a downshift is performed based on the approximate straight line Lw1 whose inclination is not appropriate, as indicated by “engine speed region for each downshift point and vehicle speed” (thick solid line) on each downshift line in FIG. In addition, the engine speed after downshifting varies greatly depending on the vehicle speed.

  In addition, the estimation accuracy of “expected vehicle speed” and “acceleration during re-acceleration” may decrease immediately after the driver's driving orientation changes. For example, as shown in FIG. 13, when the driving orientation of the driver changes, the sample group PG of the travel data before the driving orientation changes to a position far from the sample group PG due to the change of driving orientation. The running data is plotted (sample P1). Therefore, immediately after the change of the driving orientation, when the approximate straight line is obtained based on the traveling data in the sample group PG and the traveling data indicated by the sample P1, the driving orientation of the driver is appropriately reflected (estimated with high accuracy). There is a possibility that it may be obtained as an approximate line Lw2 whose slope is significantly different from that of the approximate line Lr2. In the example shown in FIG. 13, the original approximate straight line Lr2 is a straight line with a negative slope, whereas the approximate straight line Lw2 is a straight line with a positive slope. When the slope of the approximate line is positive, the output possible acceleration is obtained when the downshift point is obtained from the intersection of the curve (MAXG line) representing the output possible acceleration and the approximate line as shown in FIGS. An intersection between the curve and the approximate straight line cannot be obtained, and an appropriate downshift point cannot be obtained.

  Therefore, the controller 8 accurately estimates “expected vehicle speed” and “acceleration during reacceleration” even when the number of travel data samples is small as described above or immediately after the driver's driving orientation changes. In addition, the driving force control appropriately reflecting the driver's intention and driving intention can be executed.

  FIG. 14 shows an example of the control executed by the controller 8 in order to cope with the case where the number of samples of the traveling data is small and the situation where the driving orientation has changed. The control shown in the flowchart of FIG. 14 can be executed as another control form replacing step S2 in the flowchart of FIG. First, the approximate line L0 is updated, and a downshift point is calculated from the intersection of the approximate line L0 and the MAXG line. Further, an engine speed region for each vehicle speed is calculated (step S101). That is, a diagram of the engine speed region for each downshift point and vehicle speed as shown by the thick solid line in FIG. 12 is obtained. The approximate line L0 is a correlation line for obtaining the gradient coefficient K and the expected vehicle speed Vexp updated in step S2 in the flowchart of FIG. Therefore, the approximate straight line L0 can be calculated and updated in the same manner as described above.

  Next, it is determined whether or not the engine speed region for each vehicle speed calculated in step S101 is aligned (step S102). Specifically, it is determined whether or not the difference D between the maximum value Nemax and the minimum value Nemin in the engine speed region for each vehicle speed as shown in FIG. When the difference D is equal to or less than the predetermined value α, it is determined that the engine speed region for each vehicle speed is aligned. The predetermined value α can be set in advance based on results of a running experiment, simulation, or the like.

  If an affirmative determination is made in step S102 because the engine speed regions for the vehicle speeds are aligned, the process proceeds to step S103. In step S103, the approximate straight line LO updated in step S101 is held. In this case, since it is determined that the engine speed region for each vehicle speed is aligned, the approximate straight line LO updated in step S101 is determined to be appropriate.

  In step S104, the expected vehicle speed Vexp and the gradient coefficient K are calculated from the approximate straight line L0 held in step S103 and updated. That is, in this case, by executing a downshift based on the expected vehicle speed Vexp and reacceleration acceleration Gexp obtained from the approximate straight line L0, the engine rotation after the downshift is performed at any shift stage. It can be determined that the number is almost constant regardless of the vehicle speed. Therefore, in this step S104, the approximate vehicle speed Vexp and the approximate straight line L0 that are updated in the above-described step S101 and that are maintained in step S103 are used as they are without changing or correcting. A gradient coefficient K is calculated.

  As described above, when the expected vehicle speed Vexp is calculated and updated in step S104, 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 engine speed region for each vehicle speed is not aligned, that is, if the difference D is greater than the predetermined value α, a negative determination is made in step S102, the process proceeds to step S105. move on. In this case, when the downshift is executed based on the expected vehicle speed Vexp and the reacceleration acceleration Gexp obtained from the approximate straight line L0, as shown in FIG. 12, the engine speed after the downshift increases with the vehicle speed. It can be judged that it will vary and vary. Therefore, in the control after step S105, the approximate straight line L0 that has already been calculated is changed according to the magnitude of the inclination.

  Specifically, first, in step S105, it is determined whether or not the slope of the approximate line L0 is smaller than a predetermined value β. The predetermined value β can be set in advance based on results of a running experiment, simulation, or the like. For example, as shown in FIGS. 16 and 17, the predetermined value β is obtained by rotating the approximate line around the center of gravity Pm of a plurality of plots of travel data used for calculating the predetermined approximate line, and increasing or decreasing the inclination thereof. Can be obtained as the slope of the optimum approximate straight line La in which the engine speed regions for each vehicle speed are aligned. That is, the predetermined value β is the slope of the approximate straight line when the above-mentioned difference D is equal to or less than the predetermined value α, and therefore the predetermined value β corresponds to the median value in the present invention.

  Further, as shown in FIG. 17, when the slope of the optimum approximate straight line La is β, the approximate straight line Lb with the slope β1 smaller than the slope β and the approximate straight line Lc with the slope β2 larger than the slope β are the approximate straight lines. Both the difference D1 and the difference D2 are larger than the difference D0 in the engine speed region for each vehicle speed obtained based on La. Note that the inclination β, the inclination β1, and the inclination β2 are all negative values. Therefore, the magnitude relationship between the inclinations β, β1, and β2 is “inclination β2> inclination β> inclination β1”.

  If the inclination of the approximate straight line L0 is smaller than the predetermined value β and the determination in step S105 is affirmative, the process proceeds to step S106. In step S106, a straight line having the smallest inclination among straight lines that pass through the center of gravity Pm and satisfy the rotational speed condition is calculated as the approximate straight line L1.

  The above-mentioned rotation speed condition is, for example, that the difference D in the engine rotation speed region for each vehicle speed is a value within a range that is acceptable to the extent that the driver does not feel uncomfortable. In this case, the allowable range can be represented as a hatched area AR on a graph in which the intercept of the linear function is taken on the vertical axis and the slope is taken on the horizontal axis, as shown in FIG. A group of straight lines passing through the center of gravity Pm can be represented as a straight line Lg (broken line) on the graph shown in FIG. Therefore, the optimum approximate straight line La as described above is a point Pa whose slope is β on the straight line Lg, and the area AR is a predetermined area including this point Pa. This area AR can be set in advance based on results of running experiments, simulations, and the like. Therefore, the straight line set as the approximate straight line L1 in step S106 can be obtained as the point Pb on the straight line Lg and having the minimum inclination within the area AR.

  As described above, when the approximate line L1 is obtained in step S106, the process proceeds to step S104 described above, and the expected vehicle speed Vexp and the gradient coefficient K are calculated and updated from the approximate line L1. Then, when the expected vehicle speed Vexp and the gradient coefficient K are updated in step S104, 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 inclination of the approximate straight line L0 is greater than or equal to the predetermined value β and a negative determination is made in step S105, the process proceeds to step S107. In step S107, a straight line having the maximum inclination among straight lines that pass through the center of gravity Pm and satisfy the rotational speed condition is calculated as the approximate straight line L1. Therefore, the straight line set as the approximate straight line L1 in step S107 can be obtained as the point Pc on the straight line Lg and having the maximum inclination within the area AR.

  When the approximate straight line L1 is obtained in step S107, the process proceeds to step S104 described above, and the expected vehicle speed Vexp and the gradient coefficient K are calculated from the approximate straight line L1 and updated. Then, when the expected vehicle speed Vexp and the gradient coefficient K are updated in step S104, the process proceeds to step S4 in the flowchart of FIG. 2 and the same control as described above is executed.

  For example, in the example shown in FIG. 11 described above, when the number of travel data samples is small, the approximate straight line Lw1 that has a smaller slope (larger negative slope) than the approximate straight line Lr1 that appropriately reflects the driving orientation. Is represented as a point Pd on the straight line Lg in FIG. Therefore, the approximate straight line L1 set in that case is a straight line represented as a point Pb on the straight line Lg in FIG. 18, and as shown in FIG. 19, the approximate straight line Lw1 (that is, the approximate straight line L0) is changed to the approximate straight line Ld. (That is, the approximate straight line L1 obtained as the point Pb). As a result, as shown in (b) of FIG. 17, the engine speed regions for each vehicle speed are aligned.

  Further, in the example shown in FIG. 13 described above, immediately after the driving orientation is changed, the approximate straight line Lw2 whose slope becomes larger (becomes a positive slope) than the approximate straight line Lr2 that appropriately reflects the changed driving orientation. Is represented as a point Pe on the straight line Lg in FIG. Accordingly, the approximate straight line L1 set in that case is a straight line represented as the point Pc on the straight line Lg in FIG. 18, and as shown in FIG. 20, the approximate straight line Lw2 (that is, the approximate straight line L0) is changed to the approximate straight line Le. (That is, the approximate straight line L1 obtained as the point Pc). As a result, as shown in (b) of FIG. 17, the engine speed regions for each vehicle speed are aligned. In the example shown in FIG. 20, the approximate straight line Le is slightly deviated from the approximate straight line Lr2 that appropriately reflects the driving orientation after the change. In this case, however, the transitional state changes as the driving orientation changes. Can be handled. For this reason, the influence of the divergence as described above is small.

  Thus, by executing the control shown in the flowchart of FIG. 14, for example, even when the number of travel data samples is small, or even immediately after the driver's driving orientation changes, the engine speed region for each vehicle speed An approximate straight line is obtained such that the difference D at is less than or equal to a predetermined value α. Then, the expected vehicle speed Vexp and the gradient coefficient K are calculated based on the approximate straight line. Therefore, it is possible to suppress the estimation accuracy of the expected vehicle speed Vexp and the reacceleration acceleration Gexp from being lowered, and to perform driving force control that appropriately reflects the driver's intention and driving orientation.

  As described above, the control shown in the flowchart of FIG. 14 is effective particularly when the number of travel data samples is small. Therefore, the control shown in the flowchart of FIG. 14 is based on the precondition that, for example, the acceleration travel from when the ignition switch (or main switch) of the vehicle Ve is turned on to the present is less than a predetermined number of times. May be executed. When such acceleration traveling is less than the predetermined number of times, the control shown in the flowchart of FIG. Can do.

  In the above-described specific example, the “approximate straight line” is described as a diagram shown on the graph. However, the “approximate straight line” and the correlation line (straight line f) between the vehicle speed and the acceleration are as follows: It can also be used in the form of a function, equation, correlation expression or the like 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 (3)

In a driving force control device comprising an engine mounted on a vehicle, a driving wheel, an automatic transmission that transmits torque between the engine and the driving wheel, and a controller that controls the driving force of the vehicle,
The controller is
Calculating an approximate straight line representing the correlation between the vehicle speed and acceleration of the vehicle during acceleration traveling before the vehicle decelerates,
As a target vehicle speed when performing reacceleration after decelerating, set an expected vehicle speed estimated to be desired by the driver when reacceleration based on the approximate line,
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 traveling is performed,
Before starting the reacceleration running, a downshift is performed by setting a 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 approximate straight line is changed or held so that a difference between a maximum value and a minimum value of the engine speed after execution of the downshift determined according to the vehicle speed before the start of the downshift is equal to or less than a predetermined value. A driving force control device.
The driving force control apparatus according to claim 1,
The controller is
Changing the approximate line by changing the slope of the approximate line,
Setting the median value of the slope at which the difference is less than or equal to the predetermined value and is minimum;
Setting a region that defines a straight line group of the approximate straight lines that are changed so that the difference is equal to or less than the predetermined value;
If the current approximate straight line is outside the region and the current approximate straight line has a slope smaller than the median, the current approximate straight line is changed to a straight line having the smallest slope in the region,
If the current approximate straight line is outside the region and the current approximate straight line has a slope greater than or equal to the median value, the current approximate straight line is changed to a straight line having the maximum slope within the region. A driving force control device.
In the driving force control device according to claim 1 or 2,
The controller executes a control to change or hold the approximate straight line when the number of times of the acceleration traveling from when the main switch of the vehicle is turned on until the present is less than a predetermined number of times. A driving force control device.

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