JP2016173177A - Driving force control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive force control device which sets an appropriate gear position that reflects driver's intention and driving tendency, and enables re-acceleration traveling of a vehicle, in a situation where the vehicle is re-accelerated after being decelerated.SOLUTION: In a driving force control device of a vehicle which is mounted with an automatic transmission for gear-changing torque output by an engine and transmitting it to drive wheels, and controls a drive force on the basis of a vehicle speed and an accelerator opening, the driving force control device stores an acceleration characteristic that defines a relationship between re-acceleration-time acceleration which is set as a control index when the vehicle travels while being re-accelerated after deceleration traveling, and the vehicle speed, acquires the re-acceleration time acceleration corresponding to a current vehicle speed on the basis of traveling data of the vehicle before the deceleration traveling and the acceleration characteristic (step S3), and sets a gear change ratio at which the acquired reacceleration-time acceleration can be obtained before the re-acceleration traveling is started (step S4).SELECTED DRAWING: Figure 2

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 an invention relating to a travel control device that automatically causes a host vehicle to follow a preceding vehicle. In the traveling control device described in Patent Document 2, traveling data representing vehicle behavior, traveling environment, driving operation, and the like are sampled during traveling by a driver's operation, and a multiple regression analysis is performed on the traveling data. The driver's driving orientation (multiple regression coefficient) is obtained. Then, the vehicle is configured to automatically follow the preceding vehicle by setting a target acceleration / deceleration based on the driving orientation.

  Further, the driving force control device described in Patent Document 3 calculates a recommended gear ratio based on a road driving environment, and an optimum gear ratio based on a recommended gear ratio, a driver's gear intention, and an actual gear ratio. And the optimum gear ratio is changed at a change speed determined by the difference between the recommended gear ratio and the actual gear ratio.

JP 2007-170444 A JP 2003-211999 A JP 2002-139135 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. For this reason, the gear position or gear ratio after downshifting 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 set an appropriate shift speed (speed ratio) that reflects driving orientation and re-accelerate the vehicle.

  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. In the driving force control device that controls based on the degree, the controller includes a controller that controls the driving force, and the controller includes an acceleration at the time of reacceleration as a control index when the vehicle travels at a reduced speed after the vehicle travels at a reduced speed, and a vehicle speed. Accelerating characteristics that define the relationship with the vehicle, and control for obtaining the acceleration at the time of reacceleration corresponding to the current vehicle speed based on the traveling data of the vehicle before the deceleration traveling and the acceleration characteristics, and the reaccelerated traveling Before starting the operation, control is performed to set the speed ratio of the automatic transmission capable of realizing the acceleration at the time of reacceleration based on the acceleration at the time of reacceleration obtained. That.

  Further, the present invention provides a control in which the controller estimates an expected vehicle speed desired by a driver when the reacceleration travel is performed based on the travel data at the time of the acceleration travel before the deceleration travel, the current vehicle speed, Control for obtaining the acceleration at the time of reacceleration corresponding to the current vehicle speed based on the estimated expected vehicle speed is performed.

  Further, according to the present invention, the controller stores a plurality of acceleration characteristic lines in which the acceleration at the time of reacceleration is determined according to a vehicle speed, and selects any one of the acceleration characteristic lines based on the expected vehicle speed; Control for obtaining the acceleration at the time of reacceleration corresponding to the current vehicle speed is performed based on the current vehicle speed, the expected vehicle speed, and the selected acceleration characteristic line.

  Further, the present invention is characterized in that the controller stores the vehicle speed and acceleration at the time of starting the reacceleration running, and performs control to update the acceleration characteristic line.

  Further, in the present invention, the controller obtains the acceleration at the time of reacceleration using the average value of the acceleration at the time of reacceleration or the average value of the expected vehicle speed in the reacceleration traveling that has been performed a plurality of times in the past. Further, control is performed to set the speed ratio that can realize the acceleration at the time of reacceleration.

  The present invention is characterized in that the controller performs control to set the maximum vehicle speed recorded by the vehicle as the expected vehicle speed before starting the deceleration travel from the time when the expected vehicle speed is not set.

  In the driving force control device of the present invention, the vehicle is accelerated with the acceleration at the time of re-acceleration as described above, that is, the acceleration expected by the driver, before the re-acceleration running is started at the time of re-acceleration after deceleration. The transmission gear ratio (or shift speed) of the automatic transmission that can be set is set. The acceleration at the time of reacceleration serves as a control index at the time of reacceleration running after decelerating running, and is an estimation of an acceleration desired by the driver or an acceleration expected by the driver during the reacceleration running. The acceleration at the time of reacceleration is obtained based on acceleration characteristics stored in advance and vehicle travel data before decelerating travel. The acceleration characteristic defines the relationship between the acceleration at the time of reacceleration and the vehicle speed, and can be stored in advance. The traveling data of the vehicle is a physical quantity that represents the traveling state of the vehicle, such as vehicle speed, acceleration, automatic transmission gear ratio, or engine speed.

  Therefore, according to the driving force control apparatus of the present invention, when the reacceleration traveling after the deceleration traveling is performed, the speed ratio capable of accelerating the reacceleration is set before the reacceleration traveling is started. The shift control of the automatic transmission can be completed. In addition, by determining the acceleration at the time of reacceleration from the driving data before the deceleration and the acceleration characteristics of the vehicle as described above, the acceleration at the time of reacceleration is reflected in the control of the shift control reflecting the driver's intention and driving orientation. It can be an indicator. 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.

  For example, when the vehicle turns in a corner, it is suitable for re-acceleration of the vehicle in the exit stage from the corner in advance during the vehicle deceleration traveling from the corner entry stage to the corner turning stage. The automatic transmission can be downshifted to the gear ratio (speed stage), that is, the acceleration at the time of reacceleration. Therefore, when the vehicle enters the corner and turns, the vehicle can be appropriately decelerated and stably turned while maintaining a state where a large driving force can be obtained. When the vehicle escapes from the corner and starts reacceleration, the downshift has already been completed to a state where a sufficient driving force can be obtained as described above.

  As described above, according to the driving force control apparatus of the present invention, 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. This makes it possible to appropriately accelerate the vehicle. 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.

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 for calculating | requiring 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 figure for demonstrating the behavior (vehicle speed, acceleration, engine speed etc.) of the vehicle at the time of performing the driving force control of this invention. It is a block diagram for demonstrating the structure of the controller which comprises the driving force control apparatus 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. FIG. 10 is a diagram for explaining another control example when the driving force control of the present invention is executed for a vehicle equipped with a continuously variable transmission. It is a figure for demonstrating the other control example at the time of performing the driving force control of this invention. It is a figure for demonstrating the other control example at the time of performing the driving force control of this invention. It is a figure for demonstrating the other control example at the time of performing the driving force control of this invention. It is a figure for demonstrating the other control example at the time of performing the driving force control of this invention. It is a figure for demonstrating the other example of the control map shown in FIG. It is a figure for demonstrating the other example of the control map shown in FIG. It is a flowchart for demonstrating the other example of the driving force control by the driving force control apparatus of this invention. It is a time chart for demonstrating the example which calculates | requires "expected vehicle speed" in the driving force control of this invention. It is a flowchart for demonstrating the other example of the driving force control by the driving force control apparatus of this invention. It is a flowchart for demonstrating the other example of the driving force control by the driving force control apparatus of this invention. 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 figure for demonstrating the example which carries out learning control of the coefficient (slope) which prescribes | regulates the correlation line for calculating | requiring "expected vehicle speed" and "acceleration at the time of reacceleration" in the driving force control of this invention. FIG. 10 is a diagram for explaining another example of learning control of a coefficient (inclination) that defines a correlation line for obtaining “expected vehicle speed” and “acceleration during reacceleration” in the driving force control of the present invention. It is a flowchart for demonstrating the other example of the driving force control by the driving force control apparatus of this invention.

  Next, an embodiment of the present invention will be described with reference to the drawings. A vehicle to which the present invention can be applied is a vehicle equipped with an automatic transmission capable of shifting the power output from 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 is configured to clear the travel data when the ignition switch (or the main switch) is turned OFF, the travel history before the current deceleration travel is the vehicle Ve for the current travel. This is a history of travel data acquired from when the ignition switch 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, when acceleration running has not yet been performed since the start of this control, when the vehicle Ve is running accelerated, when the vehicle Ve is running decelerating, or when the vehicle Ve is running steady. Is negatively determined 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. In addition, when acceleration traveling has not yet been performed since the start of this control, for example, the expectation stored at the time when the ignition switch is turned on for the current traveling and this control is first started is stored. The vehicle speed Vexp and the gradient coefficient K are continuously maintained. In the configuration in which the expected vehicle speed Vexp and the gradient coefficient K are cleared when the ignition switch is turned OFF, 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.

  In the driving force control by the controller 8, travel data at the time of starting reacceleration travel is stored, and the acceleration characteristics defining the relationship between the “acceleration during reacceleration” and the vehicle speed as described above can be updated. it can. The travel data stored in this case is the vehicle speed and acceleration of the vehicle Ve when the reacceleration travel is started. The acceleration characteristics as described above are stored, for example, as an acceleration characteristic line in which “acceleration during reacceleration” is determined according to the vehicle speed. Specifically, the acceleration characteristic line is a correlation line (approximate line) as shown by “y = a · x + b” in FIG. 4 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.

In Figure 7, if the expected vehicle speed V _A, and is shown the operation image of the vehicle Ve for the case of deceleration in two ways of the case where the lower the expected vehicle speed V _B than the expected vehicle speed V _A. As shown in FIG. 7A, a downshift is performed at shift points (black circles) on the correlation line corresponding to the respective expected vehicle speeds V _A and V _B. FIG. 7B is a diagram in which the shift points shown in FIG. 7A are converted into engine speeds and displayed. Roughly, the downshift is performed in the rotational speed bands A and B corresponding to the respective expected vehicle speeds V _A and V _B.

  A specific configuration of the controller 8 that executes the control during deceleration traveling as described above is shown in a 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, as shown in FIG. It is comprised from the transmission output judgment part B6.

  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.

  FIGS. 6 and 7 show an example in which the automatic transmission 4 is a forward 8-speed stepped transmission. However, the automatic transmission 4 according to the present invention is a belt-type or toroidal-type continuously variable transmission. Alternatively, an electric continuously variable transmission mechanism in a hybrid vehicle can 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. 9A, a gear ratio γ capable of realizing “acceleration at the time of reacceleration” 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. 9B shows the behavior of the engine speed in that case.

  When the automatic transmission 4 is a continuously variable transmission or an electric continuously variable transmission mechanism of a hybrid vehicle as described above, when deceleration continues even after a downshift that increases the gear ratio during deceleration traveling is performed, As shown in FIG. 10, in the range in which “acceleration during reacceleration” can be output, specifically, in the range not exceeding the reacceleration possible acceleration output speed (dashed line) in FIG. It can also be controlled to reduce the rotational speed (solid line). Accordingly, it is possible to give the driver an appropriate feeling of deceleration when traveling at a reduced speed.

When the vehicle Ve is decelerated based on the “expected vehicle speed” and the “acceleration at the time of reacceleration” as described above, control is performed so that the use range of the engine speed is changed according to the magnitude of the “expected vehicle speed”. You can also. For example, as shown in FIG. 11, if the expected vehicle speed V _c, and, if decelerated in two ways of the case where the expected vehicle speed V lower than _c expected vehicle speed V _d, which expected vehicle speed V _c, V _d The minimum engine speed corresponding to is obtained from a map as shown in FIG. The minimum engine speed in this case is the lower limit engine speed that should be ensured in order to accelerate the vehicle Ve at “acceleration during reacceleration” during acceleration travel after this deceleration travel. Then, as shown in FIG. 11 (b), the downshift at the time of decelerating traveling is performed with the lowest engine speed obtained as described above as the lower limit. FIG. 11B shows an example in which the automatic transmission 4 is an 8-speed stepped transmission. However, the automatic transmission 4 has no control during deceleration traveling as shown in FIG. The present invention can also be applied to a stepless transmission or an electric continuously variable transmission mechanism of a hybrid vehicle. By controlling in this way, a certain regularity can be given to the downshift at the time of decelerating running, and the running feeling given to the driver at the time of downshifting can be improved.

FIG. 11 shows an example in which downshifting is performed with a predetermined minimum engine speed as a lower limit during deceleration traveling. However, the maximum engine speed is set, and deceleration driving is performed with the maximum engine speed as an upper limit. It can also be controlled to perform a time downshift. For example, as shown in FIG. 12, the expected case of the vehicle speed V _e, and, if decelerated in two ways of the case where the expected vehicle speed V _e less than the expected speed V _f, they expected vehicle speed V _e, V _f The maximum engine speed corresponding to is obtained from a map as shown in FIG. In this case, the maximum engine speed is within the range of the engine speed that must be secured in order to accelerate the vehicle Ve at “acceleration during re-acceleration” during acceleration travel after this deceleration travel, and can be reduced during deceleration travel. This is the upper limit engine speed set so that the engine speed does not rise excessively during the shift. Then, as shown in FIG. 12 (b), a downshift at the time of decelerating traveling is performed with the maximum engine speed determined as described above as the upper limit. FIG. 12B also shows an example in which the automatic transmission 4 is a forward 8-speed stepped transmission. The control during deceleration traveling as shown in FIG. 12 is also shown in FIG. Similar to the control, the automatic transmission 4 can be applied even if it is a continuously variable transmission or an electric continuously variable transmission mechanism of a hybrid vehicle.

  In the above-described embodiment, the downshift is performed based on the “expected vehicle speed” and the “current vehicle speed” and the “acceleration during reacceleration” obtained from the “expected vehicle speed” and the “current vehicle speed” during deceleration. However, it is also possible to perform control so that downshifts are performed at predetermined intervals. For example, as shown in FIG. 13, the downshift at the time of decelerating traveling is performed at regular intervals of the period t. The period t in this case can be set in advance according to the driver's driving intention. For example, when the driving orientation is sports driving orientation, downshifts are performed at regular intervals of a period t shorter than otherwise. Further, the downshift interval in this case is set within the range of the gear stage (speed ratio) that can realize the “outputtable acceleration” obtained based on the “acceleration during reacceleration” as described above. That is, during the reacceleration running after the downshift, the gear position (speed ratio) is set within a range in which the vehicle can always be accelerated with “acceleration during reacceleration”. By controlling in this way, a certain regularity can be given to the downshift at the time of decelerating traveling. In addition, it is possible to have predictability with respect to the timing of downshift. Therefore, the driving feeling given to the driver during downshifting can be improved.

  As in the above-described embodiments, when performing a downshift during deceleration traveling based on the “expected vehicle speed”, “current vehicle speed”, and “acceleration at reacceleration”, the “acceleration at reacceleration” is actually calculated after being obtained. An inevitable response delay occurs until the shift is started. If such a response delay is large, the timing of the downshift intended or predicted by the driver may not be matched, and the driver may feel uncomfortable. Therefore, for example, as shown in FIG. 14, the “current vehicle speed” (broken line) obtained from the actual vehicle speed is used to perform a downshift in advance by using the “predicted vehicle speed” (solid line) pre-read for a predetermined time. It can also be controlled. This “predicted vehicle speed” can be obtained by multiplying the acceleration (specifically, deceleration) of the vehicle Ve by the look-ahead time obtained by, for example, experiments or simulations. FIG. 14 also shows the current engine speed (broken line) corresponding to “current vehicle speed” and the predicted engine speed (solid line) corresponding to “predicted vehicle speed”. As described above, by executing the control as in each of the above-described embodiments based on the pre-read vehicle speed, it is possible to solve the problem caused by the downshift response delay as described above. As a result, the running feeling of the vehicle Ve can be improved.

  The deceleration of the vehicle Ve for obtaining the “predicted vehicle speed” can be calculated from the detection data of the output rotation speed sensor 11 and the vehicle speed sensor 12 as described above. Or it can also obtain | require from the detection data of the acceleration sensor mounted in the vehicle Ve. It can also be calculated based on detection data of a brake pressure sensor provided in the braking device.

  In the control map of FIG. 5 described above, an example in which the correlation line between the “acceleration at the time of reacceleration” and the vehicle speed is linear of a linear function is shown. However, as shown in FIG. . The correlation line between the “acceleration at the time of reacceleration” and the vehicle speed is not limited to the linear function as in the above-described embodiment, and may be expressed by a quadratic function or an exponential function, for example. In such a case, the control in each embodiment as described above can also be executed using a non-linear control map as shown in FIG.

  When the control is executed using the control maps as shown in FIGS. 5 and 15 described above, there is actually an upper limit in the acceleration expected or required by the driver during the reacceleration running. If a downshift is set by setting a gear stage (speed ratio) that generates such an acceleration exceeding the upper limit, a lower speed stage (large gear ratio) is selected than expected by the driver, The driver may feel uncomfortable. Therefore, in the control maps of FIG. 5 and FIG. 15, “acceleration at the time of re-acceleration” beyond that expected by the driver is substantially unnecessary. Therefore, for example, the control map of FIG. 5 can be set as a control map having “expected upper limit acceleration” as shown in FIG. Thus, by setting the upper limit of acceleration in consideration of the driver's intention and expected value in the control map for obtaining “acceleration at the time of reacceleration”, the driver's assumption is exceeded as described above. Therefore, it is possible to appropriately perform downshifting while avoiding setting of a different gear stage (speed ratio).

  The flowchart of FIG. 17 shows a modified example of the control shown in the flowchart of FIG. In the control example shown in the flowchart of FIG. 17, it is necessary to wait for the engine speed to become lower than a predetermined upper limit threshold so that the engine speed does not increase excessively during downshifting during deceleration traveling. Controlled to perform downshift. In the flowchart of FIG. 17, the control contents of steps S11 and S12 are added to the flowchart of FIG. Therefore, in the control example shown in the flowchart of FIG. 17, as in the control shown in the flowchart of FIG. 2, in step S1 to step S5, the expected vehicle speed Vexp, the reacceleration acceleration Gexp, and the output possible acceleration Gabl and its A gear stage (speed ratio) capable of outputting the outputable acceleration Gabl is calculated. In step S6, it is determined whether or not the vehicle Ve is traveling at a reduced speed. 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 a positive determination is made in step S7, the process proceeds to step S11.

  In step S11, an engine speed Ne1 corresponding to the calculated gear position (speed ratio) is calculated. That is, the engine speed Ne1 estimated when the calculated shift speed (speed ratio) is set and the speed is changed is obtained.

  When the engine speed Ne1 is calculated in step S11, it is determined whether or not the engine speed Ne1 is lower than the upper limit threshold (step S12). The upper limit threshold in this case is an upper limit value of the engine speed that is determined so that the engine speed does not increase excessively during a downshift during deceleration traveling.

  If the engine speed Ne1 is still greater than or equal to the upper limit threshold value and a negative determination is made in step S12, the control in step S12 is repeated without proceeding to the subsequent steps. That is, the control in step S12 is repeatedly executed until the engine speed Ne1 becomes lower than the upper limit threshold.

  If the engine speed Ne1 is lower than the upper limit threshold value and the determination is affirmative in step S12, the process proceeds to step S8. In step S8, the automatic transmission 4 performs a downshift toward the calculated shift speed (speed ratio). Thereafter, this routine is once terminated.

  As described above, when the downshift is performed in consideration of the engine speed at the time of decelerating, the engine speed increases excessively when the downshift is performed, and the driver feels uncomfortable. Can be suppressed. Therefore, the traveling feeling of the vehicle Ve in the downshift at the time of decelerating traveling can be improved.

  In the embodiment described above, the “expected vehicle speed” is obtained from a control map as shown in FIG. 5, for example. That is, the “expected vehicle speed” is obtained using the correlation between the “acceleration during reacceleration” and the vehicle speed. As described above, in the present invention, the “expected vehicle speed” is defined as the vehicle speed targeted by the driver during acceleration traveling. From such a definition, when the vehicle speed reaches the “expected vehicle speed” during acceleration traveling, it can be estimated that the acceleration becomes zero and the vehicle is not accelerated any more. Therefore, for example, as shown in the time chart of FIG. 18, the maximum vehicle speed recorded by the vehicle Ve during acceleration travel before starting the deceleration travel immediately before the current reacceleration travel (that is, the vehicle speed at which the acceleration becomes zero during travel). Can be set as the “expected vehicle speed”. The previous acceleration travel is an acceleration travel performed before starting the current deceleration travel from the time when the “expected vehicle speed” has not yet been set. For example, if the controller 8 is configured to clear the “expected vehicle speed” when the ignition switch (or main switch) is turned off, the ignition switch of the vehicle Ve is turned on for the current travel. Accelerated running has been carried out to date.

  The flowchart of FIG. 19 shows a control example in which the maximum vehicle speed in the past acceleration travel is set as the “expected vehicle speed” as described above. In the basic control shown in the flowchart of FIG. 2 described above, if a negative determination is made in step S1, the previous values of the expected vehicle speed Vexp and the gradient coefficient K are held in step S3. On the other hand, in the driving force control by the controller 8, the control shown in the flowchart of FIG. 19 can be executed instead of executing the control of step S3 in the flowchart of FIG.

  For example, if a negative determination is made in step S1 in the basic control shown in the flowchart of FIG. 2, the process proceeds to step S21 in the flowchart of FIG. In step S21, it is determined whether or not the vehicle Ve is accelerating. If the vehicle Ve is not accelerating, a negative determination is made in step S21, the process proceeds to step S22.

  In step S22, 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. That is, if it is determined in step S1 that acceleration traveling of the vehicle Ve has not yet ended or acceleration traveling has not yet been performed after the start of control, each of the expected vehicle speed Vexp and the gradient coefficient K is determined. The previous value is the expected vehicle speed Vexp and the gradient coefficient K stored when the ignition switch is turned on for the current running.

  Therefore, in this step S22, if the controller 8 is configured to clear the expected vehicle speed Vexp and the gradient coefficient K when the ignition switch is turned off, the controller 8 is turned on for the current travel. The initial values of the expected vehicle speed Vexp and the gradient coefficient K that are read and stored are held. Further, if the controller 8 is configured to store the expected vehicle speed Vexp and the gradient coefficient K at that time when the ignition switch is turned off, the expected vehicle speed Vexp stored when the ignition switch was last turned off. And the gradient coefficient K are kept.

  As described above, when the previous values of the expected vehicle speed Vexp and the gradient coefficient K are held in step S22, 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 vehicle Ve is accelerating and a positive determination is made in step S21, the process proceeds to step S23.

  In step S23, it is determined whether or not the current vehicle speed Vcur is higher than the currently set expected vehicle speed Vexp. If the current vehicle speed Vcur is less than or equal to the expected vehicle speed Vexp, and if a negative determination is made in step S23, the process proceeds to step S22 described above, and the same control as described above is executed.

  On the other hand, if the current vehicle speed Vcur is higher than the expected vehicle speed Vexp, and if a positive determination is made in step S23, the process proceeds to step S24. In step S24, the expected vehicle speed Vexp is updated. In this case, the current vehicle speed Vcur becomes a new maximum vehicle speed because the current vehicle speed Vcur is higher than the expected vehicle speed Vexp, which was the maximum vehicle speed in the past acceleration travel. Therefore, the new maximum vehicle speed is set as the latest expected vehicle speed Vexp. In step S24, the gradient coefficient K is held at the previous value as in step S22 described above, for example. As described above, in step S24, the expected vehicle speed Vexp is updated without directly using the correlation or correlation line between the vehicle speed and acceleration in the travel data during acceleration travel. Therefore, the gradient coefficient K, which is the inclination of the correlation line, is not updated in step S24, but the previous value is held.

  As described above, when the expected vehicle speed Vexp is updated in step S24, step S4 in the flowchart of FIG. 2 is performed as in the case where the previous values of the expected vehicle speed Vexp and the gradient coefficient K are held in step S22 described above. Then, the same control as described above is executed.

  In the control shown in the flowchart of FIG. 19, when the “expected vehicle speed” is updated, the “expected vehicle speed” can be easily obtained without executing particularly complicated calculation processing. Therefore, the load on the controller 8 can be reduced. In addition, since the opportunity to update the “expected vehicle speed” is provided even during acceleration traveling, the update frequency of the “expected vehicle speed” can be increased and the estimation accuracy can be improved.

  In the basic control shown in the flowchart of FIG. 2 described above, when the acceleration traveling of the vehicle Ve is completed, if the determination in step S1 is affirmative, the traveling of the vehicle Ve stored in step S2 during the last acceleration traveling is performed. Based on the data, the expected vehicle speed Vexp and the gradient coefficient K are updated. On the other hand, in the driving force control by the controller 8, instead of executing the control of step S2 in the flowchart of FIG. 2, the control shown in the flowchart of FIG. 20 below can be executed. That is, in the driving force control by the controller 8, the “expected vehicle speed” can be obtained as in the control example shown in the flowchart of FIG.

  If it is determined affirmative in step S1 in the basic control shown in the flowchart of FIG. 2 because the acceleration traveling of the vehicle Ve has ended, the process proceeds to step S31 in the flowchart of FIG. In step S31, the expected vehicle speed Vexp and the gradient coefficient K are calculated. Similar to step S2 in the flowchart of FIG. 2 described above, the vehicle Ve is calculated based on the travel data (vehicle speed at the start of acceleration, maximum acceleration during acceleration travel, etc.) stored during acceleration travel determined to be finished. The expected vehicle speed Vexp and the gradient coefficient K are set.

  In addition, as the expected vehicle speed Vexp calculated here, an average value of the expected vehicle speed Vexp set at the time of reacceleration traveling that has been performed a plurality of times in the past can be used. For example, the average value of the expected vehicle speed Vexp for the latest several times including the latest is calculated, and the average value is set as the latest expected vehicle speed Vexp in step S31.

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

  In step S33, 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 S22 in the flowchart of FIG. In this case, it is determined that the acceleration traveling of the vehicle Ve has once ended. Therefore, the previous values of the expected vehicle speed Vexp and the gradient coefficient K in this case are the expected vehicle speed Vexp and the gradient coefficient K that are calculated and stored when the previous acceleration travel is finished.

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

  As described above, when the expected vehicle speed Vexp and the gradient coefficient K are updated in step S34, the previous values of the expected vehicle speed Vexp and the gradient coefficient K are held in step S33 described above, as in FIG. Proceeding to step S4 in the flowchart, the same control as described above is executed. That is, the reacceleration acceleration Gexp is calculated based on the previous values of the expected vehicle speed Vexp and the gradient coefficient K held in step S33 or the latest expected vehicle speed Vexp and the gradient coefficient K updated in step S34. .

  The reacceleration acceleration Gexp calculated here can be the average value of the reacceleration acceleration Gexp set during reacceleration running that has been carried out a plurality of times in the past, similarly to the expected vehicle speed Vexp. For example, the average value of the accelerations Gexp for the latest several accelerations including the latest is calculated, and the average value is set as the acceleration Gexp for the latest acceleration.

  As described above, in the control shown in the flowchart of FIG. 20, the expected vehicle speed Vexp updated at least twice after the completion of the acceleration travel is set based on the latest expected vehicle speed Vexp and the last updated expected vehicle speed Vexp. . Alternatively, the expected vehicle speed Vexp is set based on the average value of the expected vehicle speed Vexp obtained at the time of reacceleration traveling that has been performed a plurality of times in the past. Then, a reacceleration acceleration Gexp is set based on the expected vehicle speed Vexp thus set. This re-acceleration acceleration Gexp can also be set based on the average value of the re-acceleration acceleration Gexp obtained during re-acceleration running that has been performed a plurality of times in the past. Therefore, according to the control shown in the flowchart of FIG. 20, the influence of the error in the travel data used to calculate the “expected vehicle speed” is suppressed, and the estimation accuracy of the “expected vehicle speed” and “acceleration at reacceleration” is increased. Can be improved.

  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. 21, a point 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 “w = 0.7”, for example, when running data is weighted, 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.

  In the control map as shown in FIG. 5 described above, the straight line f for estimating the “acceleration during reacceleration” from the “expected vehicle speed” is defined by the gradient coefficient K. By updating the gradient coefficient K by learning, it is possible to improve the estimation accuracy of “acceleration during reacceleration”. For example, as shown in FIG. 23, when the actual ground acceleration of the vehicle Ve is smaller than the “acceleration at the time of reacceleration” estimated from the straight line f of the gradient coefficient K, the “expected vehicle speed” remains constant and the actual The gradient coefficient K is learned so that the ground acceleration becomes “acceleration during reacceleration”. In the example shown in FIG. 23, the gradient coefficient K is changed to a gradient coefficient K ′ that becomes smaller by learning. If the actual ground acceleration is larger than the “acceleration at the time of reacceleration” estimated from the straight line f of the gradient coefficient K, the gradient coefficient K is changed to a larger side by learning. The learning of the gradient coefficient K as described above can be performed based on the past one-time data, but by obtaining the learning value of the gradient coefficient K with reference to a plurality of times of data, the “re-acceleration can be performed more accurately. The "time acceleration" can be estimated.

  When the gradient coefficient K is learned as in the embodiment shown in FIG. 23 above, if the gradient coefficient K is excessive, the “acceleration at reacceleration” occurs when the difference between the “expected vehicle speed” and the “current vehicle speed” is large. The estimated value of “is also excessive. As a result, a low gear (larger gear ratio) than that assumed by the driver is selected, which may give the driver a sense of discomfort. Therefore, when the gradient coefficient K is learned as described above, an upper limit may be provided for the learned value. For example, as shown in FIG. 24, when the actual ground acceleration of the vehicle Ve is larger than the “acceleration during reacceleration” estimated from the straight line f of the gradient coefficient K, first, the “expected vehicle speed” remains constant. The gradient coefficient K is increased so that the actual ground acceleration becomes “acceleration during reacceleration”. In this case, however, a predetermined gradient coefficient K ″ is set as the upper limit. Even if the gradient coefficient K is increased to the upper limit gradient coefficient K ″, the actual acceleration to ground and the “acceleration during reacceleration” match. If not, the “expected vehicle speed” is changed to a larger side, and the straight line f ″ is set so that the actual ground acceleration becomes the “acceleration during reacceleration”.

  In this way, by setting the upper limit and learning the gradient coefficient K, it is possible to accurately estimate the “acceleration during reacceleration” while avoiding that the estimated value of “acceleration during reacceleration” becomes excessive. be able to.

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

  When the expected vehicle speed Vexp is updated based on the learned value of the gradient coefficient K as described above, the process proceeds to step S4. And the control similar to the content mentioned above is performed after the step S4.

  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 (6)

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
Storing acceleration characteristics that define the relationship between the acceleration at the time of reacceleration and the vehicle speed as a control index when reaccelerated after the vehicle has decelerated,
Control for obtaining the acceleration at the time of reacceleration corresponding to the current vehicle speed based on the running data of the vehicle before the decelerating running and the acceleration characteristics;
Before starting the reacceleration running, control is performed to set a gear ratio of the automatic transmission capable of realizing the acceleration at the time of reacceleration based on the obtained acceleration at the time of reacceleration. Control device. The driving force control apparatus according to claim 1,
The controller is
Control for estimating an expected vehicle speed desired by a driver when the reacceleration travel is performed based on the travel data during acceleration travel before the deceleration travel;
A driving force control device that performs control for obtaining the acceleration at the time of reacceleration corresponding to the current vehicle speed based on the current vehicle speed and the estimated expected vehicle speed. The driving force control apparatus according to claim 2,
The controller is
Storing a plurality of acceleration characteristic lines in which the acceleration at the time of reacceleration is determined according to a vehicle speed;
Control for selecting any one of the acceleration characteristic lines based on the expected vehicle speed;
A driving force control device that performs control for obtaining the acceleration at the time of reacceleration corresponding to the current vehicle speed based on the current vehicle speed, the expected vehicle speed, and the selected acceleration characteristic line. The driving force control apparatus according to claim 3,
The controller stores a vehicle speed and acceleration at the time of starting the reacceleration running, and performs control to update the acceleration characteristic line. In the driving force control device according to any one of claims 2 to 4,
The controller obtains the acceleration at the time of reacceleration using the average value of the acceleration at the time of reacceleration or the average value of the expected vehicle speed in the reacceleration traveling that has been performed a plurality of times in the past, and the obtained acceleration at the time of reacceleration A driving force control device that performs control to set a gear ratio of the automatic transmission capable of realizing the above. In the driving force control device according to any one of claims 2 to 5,
The controller performs a control to set a maximum vehicle speed recorded by the vehicle as the expected vehicle speed before starting the deceleration travel from a time point when the expected vehicle speed is not set.

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