JP2018135912A - Control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform stable deceleration traveling by generating a proper brake force by an engine brake when decelerating a towing-traveling vehicle.SOLUTION: A rear shaft load acting on an axle of a rear wheel is estimated in a state that a vehicle stops on a flat road on the basis of vehicle height displacement (steps S1 to S3), when the vehicle deceleration-travels, a deceleration difference is acquired from actual acceleration which is detected as current back and forth acceleration, and reference acceleration which is predetermined as standard deceleration which decelerates the vehicle by accelerator-off in a state that the vehicle travels on the flat road (step S8), a correction value for correcting a target gear change ratio in a direction in which a gear change ratio becomes large is acquired on the basis of the rear shaft load and angular displacement (step S9), and the target gear change ratio is set on the basis of a vehicle speed, the deceleration difference and the correction value (step S10).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control device that controls a vehicle equipped with an automatic transmission, and more particularly to a vehicle control device that controls deceleration of a vehicle during deceleration traveling.

  Patent Document 1 describes a deceleration traveling control device for the purpose of improving the fuel efficiency of a vehicle during deceleration traveling. In the control device described in this patent document 1, when the vehicle is traveling off the accelerator, the first deceleration control that decelerates by applying the engine brake in a state where the fuel cut is performed, and the drive range of the vehicle while injecting fuel are performed. In this state, the second deceleration control for decelerating by applying the engine brake is selectively executed. Specifically, the fuel consumption amount when the first deceleration control and the second deceleration control are executed is predicted based on environmental information in a predetermined section before the stop. Of the first deceleration control and the second deceleration control, the deceleration control with the smaller predicted fuel consumption is selected and executed. The environmental information includes at least one of vehicle air resistance, road load, road surface gradient, weather, road surface friction coefficient, road surface type, atmospheric pressure, altitude, temperature, vehicle weight, load weight, and number of passengers. .

  Patent Document 2 describes a control device for a vehicle power transmission device configured to set a braking torque (engine braking torque) by engine braking to be larger when towing than when there is no towing. In the control device described in Patent Document 2, the engine brake torque at the time of towing is set to be larger as the speed stage is at a lower speed stage than at the time without towing.

  Further, Patent Document 3 describes a vehicle deceleration control device intended to obtain a braking force desired by a driver regardless of changes in braking performance due to the presence or absence of towing of a trailer or the like. ing. In the control device described in Patent Document 3, the presence or absence of traction is determined based on the vehicle weight calculated from the actual running state of the vehicle. When towing, the target deceleration is set larger than when there is no towing.

  Patent Document 4 describes a vehicle behavior control device for the purpose of accurately determining whether or not a vehicle is being pulled. In the control device described in Patent Document 4, it is determined whether or not the vehicle is in the towing state based on the relationship between the tire driving force of the drive wheel and the slip ratio.

  Patent Document 5 describes a shift control method for an automatic transmission in which the driving force is controlled using a plurality of intermediate gears when the vehicle loading weight is equal to or greater than a predetermined value.

International Publication No. 2014/115268 JP 2009-41599 A JP 2006-348840 A JP 2014-113955 A JP 61-84453 A

  As described above, in the control device described in Patent Document 1, deceleration control is performed in consideration of environmental information of the vehicle during deceleration traveling. However, the environmental information considered at that time includes loading weight, road surface gradient, and the like, but the presence or absence of traction is not considered. Therefore, when the vehicle travels at a reduced speed in the towing state, there is a possibility that appropriate deceleration control cannot be performed. For example, as shown in FIG. 4 to be described later, when the vehicle Ve pulls the trailer 14 connected by the hitch member 8, the load applied to the axle of the vehicle Ve via the hitch member 8 is very small in the stationary state, but is decelerated. When traveling, the downward component increases in the vertical direction. That is, the loading weight of the vehicle increases. Such a downward load in the vertical direction becomes even larger particularly when the vehicle runs at a reduced speed on a downhill road. When the load applied to the axle increases, a larger braking force is required to appropriately decelerate the vehicle. When the transmission is downshifted to generate a braking force by engine braking, it is necessary to shift to a lower speed (or a higher gear ratio) to generate a larger braking force. Thus, when the vehicle is towed, the load weight changes according to the traveling state and the road surface condition. Therefore, when the conventional deceleration control as described in Patent Document 1 is performed without considering the traction state of the vehicle, an appropriate braking force by the engine brake cannot be obtained, and stable deceleration traveling can be performed. There is a risk of disappearing.

  The present invention has been conceived by paying attention to the technical problems as described above, and realizes stable deceleration traveling by generating an appropriate braking force by an engine brake when decelerating a towing vehicle. An object of the present invention is to provide a vehicle control device that can perform the above-described operation.

  To achieve the above object, the present invention provides an engine, drive wheels, an automatic transmission for transmitting torque between the engine and the drive wheels, and a connecting device for connecting a towed vehicle. A sensor for detecting vehicle speed, a sensor for detecting vehicle height displacement in the vehicle height direction, a sensor for detecting angular displacement in the pitching direction, a sensor for detecting longitudinal acceleration, and the automatic A controller for executing transmission control of the transmission, setting a target transmission ratio for the automatic transmission, and controlling the transmission ratio of the automatic transmission based on the target transmission ratio. Is based on the vehicle height displacement, and estimates the rear axle load acting on the rear axle when the vehicle is stopped on a flat road. Determining the deceleration difference from the difference between the actual acceleration detected as a degree and a reference acceleration predetermined as a standard deceleration when the vehicle is traveling on a flat road and decelerating with the accelerator off, Based on the rear axle load and the angular displacement, a correction value for correcting the target speed ratio in a direction in which the speed ratio increases is obtained, and based on the vehicle speed, the deceleration difference, and the correction value, the target speed change ratio is obtained. The control device is characterized by setting a ratio.

  According to the present invention, when the vehicle travels at a reduced speed, the gear ratio of the automatic transmission is obtained so that an appropriate amount of braking force can be obtained by the engine brake in consideration of the loaded weight of the vehicle and the traction state. Alternatively, the gear position is controlled. Therefore, even when the vehicle decelerates while being pulled, the vehicle and the towed vehicle can be decelerated stably.

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 shift control performed with the control apparatus of this invention. In shift control executed by the control device of the present invention, it is a diagram for explaining an image of correction to the low speed gear stage side as the pitching angle is smaller and the rear axle load is larger. It is a figure for demonstrating the behavior at the time of the vehicle which pulls the towed vehicle connected with the connection apparatus decelerating. It is a figure for demonstrating the behavior at the time of the normal vehicle which does not tow | run to decelerate. It is a figure which shows the map used by the shift control performed with the control apparatus of this invention, Comprising: It is a figure for demonstrating the correction | amendment which makes it easy to set the low speed side gear stage, so that a pitching angle is small. It is a figure which shows the map used by the speed change control performed with the control apparatus of this invention, Comprising: It is a figure for demonstrating the correction | amendment which makes it easy to set the low speed side gear stage, so that a rear axle load is large.

  Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a vehicle to which the present invention can be applied. A vehicle Ve shown in FIG. 1 has front wheels 1 and rear wheels 2, and includes an engine 3 as a driving force source. An automatic transmission 4 is connected to the output side of the engine 3. A propeller shaft 5 is connected to the output side of the automatic transmission 4. The propeller shaft 5 is connected to the rear wheel 2 that is a drive wheel via a differential gear 6 that is a final reduction gear and a left and right drive shaft 7. That is, in the example shown in FIG. 1, the vehicle Ve is configured as a rear-wheel drive vehicle that transmits the power output from the engine 3 to the rear wheels 2 to generate driving force. The vehicle Ve in the embodiment of the present invention may be a front-wheel drive vehicle that transmits the power output from the engine 3 to the front wheels 1 to generate driving force. 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 is an internal combustion engine such as a gasoline engine or a diesel engine, for example. The engine 3 is configured such that output adjustment, start and stop operations, and the like are electrically controlled. In the case of a gasoline engine, the throttle valve opening, fuel supply amount, execution and stop of ignition, and ignition timing are electrically controlled. In the case of a diesel engine, the throttle valve opening, fuel injection amount, fuel injection timing, and the like are electrically controlled.

  The automatic transmission 4 is a conventional general stepped automatic transmission that includes, for example, a planetary gear mechanism (not shown) and a clutch / brake mechanism (not shown). Therefore, the automatic transmission 4 can automatically control the speed (or speed ratio) set by the automatic transmission 4 by controlling the operation of the clutch mechanism and the brake mechanism, that is, by executing the shift control. it can. The automatic transmission 4 according to the embodiment of the present invention is 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. May be.

  Furthermore, a hitch member 8 is attached to the vehicle Ve. The hitch member 8 is a connecting device for connecting the vehicle Ve and the towed vehicle when towing a towed vehicle such as a camping trailer or a cargo trailer. For example, the vehicle Ve and the trailer are connected by fitting the hitch coupler 8b attached to the trailer side to the hitch ball 8a of the hitch member 8. Note that the towed vehicle in the embodiment of the present invention is intended for a vehicle to be connected to the towed vehicle by a connecting device such as the hitch member 8 described above or a coupler and a kingpin. In the embodiment of the present invention, a state where the towed vehicle is connected to the vehicle Ve by the connecting device as described above and is towed is defined as “towing”. Therefore, for example, the state of towing a broken vehicle using a wire rope, a chain, or the like is not included in “towing” in the embodiment of the present invention.

  Further, the vehicle Ve includes a leveling sensor 9. The leveling sensor 9 detects displacement (vehicle height displacement) in the vertical direction (vehicle height direction) of the vehicle body from the stroke amount of the suspension, and functions as a vehicle height sensor (height sensor). The leveling sensor 9 is provided at least on a suspension (not shown) of the rear wheel 2. Further, for example, if the vehicle Ve includes an auto leveling system for automatically adjusting the optical axis of the headlamp, the leveling sensor in that system can also be used.

  A controller (ECU) 10 for controlling the vehicle Ve as described above is provided. The controller 10 is an electronic control device mainly composed of, for example, a microcomputer. In addition to the leveling sensor 9 described above, the controller 10 typically includes a wheel speed sensor 11 for detecting the vehicle speed from the rotational speeds of the front wheels 1 and the rear wheels 2, and an output shaft (not shown) of the automatic transmission 4. Detection signals such as a rotation speed sensor 12 for detecting the rotation speed of the vehicle and an acceleration sensor 13 for detecting the longitudinal acceleration of the vehicle Ve are input. Then, the controller 10 performs calculations using various input data and data or calculation formulas stored in advance, and outputs the calculation results as a control command signal to control the vehicle Ve. It is configured. Although FIG. 1 shows an example in which one controller 10 is provided, a plurality of controllers 10 may be provided for each device or device to be controlled, or for each control content.

  As described above, the controller 10 according to the embodiment of the present invention is configured to execute the shift control for generating an appropriate braking force by the engine brake when the vehicle Ve decelerates while being towed. Has been. An example of such control is shown in the flowchart of FIG. The control shown in the flowchart of FIG. 2 is executed when the vehicle Ve travels at a reduced speed. For example, it is executed when the traveling vehicle Ve decelerates at a deceleration greater than a predetermined value. In the flowchart of FIG. 2, it is first determined whether or not the vehicle Ve has stopped (step S1). For example, the stop state of the vehicle Ve can be determined based on the detection value of the wheel speed sensor 11 or the rotation speed sensor 12 or the detection value of the acceleration sensor 13. If the vehicle Ve is stopped and the determination in step S1 is affirmative, the process proceeds to step S2.

  In step S2, it is determined whether the longitudinal acceleration of the vehicle Ve is within a set value range. The value detected by the acceleration sensor 13 is used for the longitudinal acceleration in step S2. That is, in this step S2, the road surface gradient is estimated by detecting the action state of the gravitational acceleration using the acceleration sensor 13. For example, when the detected value of the acceleration sensor 13 is within a predetermined set value range, it is determined that the road surface gradient is almost zero, that is, the vehicle Ve is in a state of being stopped on a flat road.

  When the acceleration sensor 13 determines that the longitudinal acceleration of the vehicle Ve is out of the set value range and thus a negative determination is made in step S2, the process returns to step S1 and the previous control content is repeated. On the other hand, if the longitudinal acceleration of the vehicle Ve detected by the acceleration sensor 13 is within the set value range and the determination is affirmative in step S2, the process proceeds to step S3.

  In step S3, based on the detection value of the leveling sensor 9, the load (rear shaft load) applied to the axle (rear shaft, that is, the drive shaft 7 in the example shown in FIG. 1) of the rear wheel 2 is calculated. As described above, the leveling sensor 9 is provided in the suspension of the rear wheel 2, and the rear axle load can be calculated by detecting the sinking amount of the suspension.

  When the rear axle load is calculated in step S3, the process returns to step S1 and the previous control content is repeated. That is, in steps S1 to S3 described above, the rear axle load acting on the rear axle is calculated in a state where the vehicle Ve is stopped on a flat road. The value of the rear axle load calculated in step S is stored in the controller 10. Further, it is updated as needed when the rear axle load is newly calculated.

  On the other hand, if the vehicle Ve is not stopped, that is, if the vehicle Ve is traveling at a predetermined vehicle speed or higher and thus a negative determination is made in step S1, the process proceeds to step S4.

  In step S4, the reference acceleration A is selected according to the vehicle speed. The reference acceleration A is standard deceleration data when the vehicle Ve travels on a flat road at a predetermined vehicle speed and decelerates with the accelerator off. The reference acceleration A is obtained in advance based on, for example, the results of running experiments and simulations, and the value of the reference acceleration A corresponding to each predetermined vehicle speed is stored in the controller 10. Accordingly, in this step S4, the current vehicle speed is detected, and the value of the reference acceleration A corresponding to the vehicle speed is read.

  In step S5, the actual acceleration B is calculated. The actual acceleration B is an actual deceleration at the present time of the vehicle Ve traveling at a reduced speed. In addition to the longitudinal acceleration detected by the acceleration sensor 13, the actual acceleration B is estimated based on, for example, the rotational speed (output rotational speed) of the output shaft of the automatic transmission 4 detected by the rotational speed sensor 12. Alternatively, the actual acceleration B can be estimated based on the rotational speeds of the front wheels 1 and the rear wheels 2 detected by the wheel speed sensor 11.

  In step S6, the longitudinal acceleration C is calculated. The longitudinal acceleration C is a deceleration in the longitudinal direction of the vehicle Ve. As the longitudinal acceleration C in step S6, the value detected by the acceleration sensor 13 is used as in step S2.

  In step S7, the pitching angle of the vehicle Ve is calculated from the actual acceleration B and the longitudinal acceleration C obtained as described above. The pitching angle is an angle representing the displacement of the vehicle Ve in the pitching direction (angular displacement). Specifically, the pitching angle is estimated based on the difference between the actual acceleration B and the longitudinal acceleration C. The actual acceleration B is calculated from the detection value of the wheel speed sensor 11 or the rotation speed sensor 12 as a differential value of the vehicle speed, whereas the longitudinal acceleration C is determined based on the detection value of the acceleration sensor 13. Therefore, the longitudinal acceleration C includes a gravitational acceleration component. Therefore, the pitching angle can be estimated by calculating the difference between the actual acceleration B and the longitudinal acceleration C and analyzing the value. Further, when the vehicle Ve includes a gyro sensor, the pitching angle can be measured by the gyro sensor.

  In step S8, a deceleration difference is calculated. The deceleration difference is a difference between the reference acceleration A selected in step S4 and the actual acceleration B calculated in step S5. As will be described later, in the shift control according to the embodiment of the present invention, for example, maps as shown in FIGS. 6 and 7 are provided, and the deceleration difference calculated in step S8 and the maps shown in FIGS. Based on the map as shown, the gear position in the automatic transmission 4 at the time of decelerating traveling is set.

  In step S9, a correction value for the gear position setting threshold is calculated from the rear axle load and the pitching angle. Specifically, the gear position setting threshold in the shift control of the automatic transmission 4 is corrected based on the rear axle load calculated in step S3 and the pitching angle calculated in step S7. As shown in the image in FIG. 3, the correction value for the gear position setting threshold is a value that makes it easier to set the lower gear position as the rear axle load is larger and the pitching angle is smaller. In other words, the correction value for the gear position setting threshold is a value for correcting the target gear ratio in the gear shift control of the automatic transmission 4 in a direction in which the gear ratio increases as the rear axle load increases or the pitching angle decreases. It has become.

  As shown in FIG. 4, for example, when the vehicle Ve pulls the trailer 14 and travels at a reduced speed, a downward load is applied to the hitch member 8 of the vehicle Ve in the vertical direction. On the other hand, when the vehicle Ve travels at a reduced speed, pitching occurs in the direction of the so-called nose dive posture. As shown in FIG. 5, when the vehicle Ve travels at a reduced speed in a state where it is not towed, pitching corresponding to the loaded weight or the rear axle load occurs. If a vehicle Ve (without towing) loaded with a weight equivalent to that of the trailer 14 shown in FIG. 4 travels at a reduced speed, pitching occurs at a large pitching angle as shown in FIG. On the other hand, as shown in FIG. 4, when the vehicle Ve towing the trailer 14 travels at a reduced speed, the downward load of the hitch member 8 acts as described above. The pitching angle becomes smaller compared to the state without traction. Such a tendency that the pitching angle becomes smaller becomes more prominent when the vehicle Ve towing the trailer 14 decelerates on a downhill road.

  In consideration of the above-described phenomenon, in the shift control of the automatic transmission 4 according to the embodiment of the present invention, the pitching pitch (standard pitching angle) that is assumed to be generated during normal deceleration traveling without the vehicle Ve towing. When the pitching angle of the pitching actually generated is smaller than that, it is determined that a downward load is applied to the hitch member 8, and the vehicle Ve is determined to be in a towing state. Accordingly, in step S9 in the flowchart of FIG. 2 described above, the gear position setting threshold is corrected so that the lower speed gear position is more easily set as the rear axle load is larger and the pitching angle is smaller.

  For example, as shown in FIG. 6, in a shift map in which the shift stage of the automatic transmission 4 is set according to the deceleration difference and the vehicle speed, when the pitching angle is relatively large, the shift stage that is particularly prohibited during deceleration. There is no. On the other hand, when the pitching angle is relatively small, the sixth speed (6th) and the fifth speed (5th) are prohibited during deceleration, or the sixth speed (6th) to the fourth speed (4th) ) Is prohibited. Therefore, when the pitching angle is relatively small, the shift speeds that can be set during deceleration are from the fourth speed to the first speed, or from the third speed to the first speed. That is, the smaller the pitching angle, the easier it is to set the low speed stage of the fourth speed or less or the third speed or less.

  Further, as shown in FIG. 7, in the shift map in which the shift stage of the automatic transmission 4 is set according to the deceleration difference and the vehicle speed, when the load weight (rear axle load) is relatively small, There are no prohibited gears. On the other hand, when the load weight (rear axle load) is relatively large, the sixth speed (6th) and the fifth speed (5th) are prohibited during deceleration, or from the sixth speed (6th). Fourth speed (4th) is prohibited. Therefore, when the loaded weight (rear axle load) is relatively large, the shift speeds that can be set during deceleration are from the fourth speed to the first speed, or from the third speed to the first speed. That is, the smaller the pitching angle, the easier it is to set the low speed stage of the fourth speed or lower or the low speed stage of the third speed or lower.

  In step S10, the target gear position (target gear ratio) in the shift control of the automatic transmission 4 is set from the deceleration difference, the vehicle speed, and the correction value of the gear position setting threshold. As described above, when it is determined that the vehicle Ve is in the towing state, a low-speed shift stage is more easily set than the standard shift stage set in the normal traveling state. That is, it becomes easy to apply the engine brake during deceleration traveling, and the braking force by the engine brake increases. In addition, since the rear axle load is large, when it is determined that the load on the vehicle Ve is large, it is easier to set a lower gear than the standard gear set in the normal traveling state. That is, it becomes easy to apply the engine brake during deceleration traveling, and the braking force by the engine brake increases.

  In step S11, the automatic transmission 4 is shifted based on the target gear stage (target gear ratio) set in step S10. As described above, the gear position setting threshold value is corrected, and the shift control is executed based on the corrected gear position setting threshold value, so that the vehicle Ve loaded weight, the traction state, the traction weight, and the like during deceleration traveling. Accordingly, it is possible to generate a braking force of an appropriate magnitude by the engine brake. As a result, even when the vehicle Ve travels at a reduced speed in the towing state, the vehicle Ve and the towed vehicle can be decelerated stably. When the automatic transmission 4 is shifted in this step S11. Thereafter, this routine is temporarily terminated.

  DESCRIPTION OF SYMBOLS 1 ... Front wheel, 2 ... Rear wheel (drive wheel), 3 ... Engine (ENG), 4 ... Automatic transmission (AT), 5 ... Propeller shaft, 6 ... Differential gear, 7 ... Drive shaft (rear shaft), 8 ... Hitch member (coupling device), 9 ... Leveling sensor (vehicle height sensor), 10 ... Controller (ECU), 11 ... Wheel speed sensor, 12 ... Rotational speed sensor, 13 ... Acceleration sensor, 14 ... Trailer (towed vehicle), Ve …vehicle.

Claims (1)

An engine, driving wheels, an automatic transmission for transmitting torque between the engine and the driving wheels, a connecting device for connecting a towed vehicle, a sensor for detecting a vehicle speed, and a vehicle height direction A sensor for detecting the vehicle height displacement, a sensor for detecting the angular displacement in the pitching direction, a sensor for detecting the longitudinal acceleration, and a controller for executing the shift control of the automatic transmission, In a vehicle control device that sets a target gear ratio for the automatic transmission and controls the gear ratio of the automatic transmission based on the target gear ratio,
The controller is
Based on the vehicle height displacement, estimating the rear axle load acting on the axle of the rear wheel while the vehicle is stopped on a flat road,
When the vehicle decelerates,
A deceleration difference from the difference between the actual acceleration detected as the current longitudinal acceleration and a reference acceleration predetermined as a standard deceleration when the vehicle is traveling on a flat road and decelerates with the accelerator off. Seeking
Based on the rear axle load and the angular displacement, a correction value for correcting the target gear ratio in a direction in which the gear ratio increases is obtained.
The vehicle control apparatus, wherein the target gear ratio is set based on the vehicle speed, the deceleration difference, and the correction value.

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