JP2024038582A - Vehicle control device - Google Patents

Abstract

To provide a vehicle control device capable of easily and appropriately controlling behavior or posture of a vehicle in a pitching direction by adjusting distribution of drive force between front and rear wheels even when the vehicle is traveling on a slope or is stopped midway thereof.SOLUTION: A vehicle control device is capable of generating drive force by transmitting output torque from a drive force source each of a front wheel 6 and a rear wheel 7 and adjusting distribution of the drive force between the front and rear wheels. The vehicle control device detects various parameters to determine a travel state and a travel environment of a vehicle Ve, controls the drive force of the vehicle Ve with predetermined standard drive force distribution, corrects the standard drive force distribution according to at least either the travel state or the travel environment of the vehicle Ve and controls the drive force of the vehicle Ve with the corrected drive force distribution between the front and rear wheels (Steps S6 and S7).SELECTED DRAWING: Figure 5

Description

The present invention relates to a vehicle control device capable of controlling driving force by changing the driving force distribution between front and rear wheels.

Patent Document 1 describes a control device for a vehicle (four-wheel drive vehicle) that aims to appropriately switch from 2WD mode to 4WD mode and improve running stability and safety of the vehicle. There is. The vehicle control device described in Patent Document 1 includes a switching device that selects and switches between a 2WD mode and a 4WD mode, and a rain detection device that detects rain. If the 2WD mode is selected when the rain detection means detects rain, the system is configured to notify the driver that switching to the 4WD mode is recommended.

Japanese Patent Application Publication No. 2011-156933

The vehicle described in Patent Document 1 mentioned above has a front wheel drive mode (2WD mode) in which the driving force distribution between the front and rear wheels is 100% for the front wheels (0% for the rear wheels), and a front wheel drive mode (2WD mode) in which the front wheels are distributed at 100% (0% for the rear wheels). It is possible to switch to a four-wheel drive state (4WD mode) in which power is distributed to both rear wheels. That is, the vehicle described in Patent Document 1 can control the driving force by changing the driving force distribution between the front and rear wheels within a predetermined ratio range. In a vehicle having such a configuration, the behavior of the vehicle, particularly the behavior of the vehicle in the pitching direction, can be controlled by changing the distribution of driving force between the front and rear wheels. For example, by increasing the drive force distribution to the rear wheels than to the front wheels, it is possible to suppress the phenomenon in which the rear wheels sink when the vehicle starts or accelerates (so-called squat or tail squat), and pitching can be suppressed. . However, if the road surface on which the vehicle is traveling is not flat and has an upward or downward slope, the pitching behavior described above cannot be controlled normally (as in the case of a flat road).

In this way, conventional vehicle control technology controls the distribution of driving force between the front and rear wheels when the vehicle is traveling up or down a slope, or when the vehicle is stopped in the middle of a slope. There is still room for improvement in easily controlling vehicle behavior.

This invention was devised with a focus on the above-mentioned technical problem, and it is possible to drive the front and rear wheels even when the vehicle is traveling on a slope or when the vehicle is stopped in the middle of a slope. It is an object of the present invention to provide a vehicle control device that can easily and appropriately control vehicle behavior or posture in a pitching direction by controlling force distribution.

In order to achieve the above object, the present invention provides a vehicle capable of generating driving force by transmitting the output torque of a driving power source to front wheels and rear wheels, respectively, and changing the driving force distribution between the front and rear wheels. A control device comprising: a detection unit that detects or calculates various parameters for determining at least one of a driving state and a driving environment of the vehicle; and a controller that controls the driving force based on the driving force distribution. , the controller controls the driving force according to a predetermined standard driving force distribution, and controls the driving force according to at least one of the driving state and the driving environment determined based on the various parameters. The present invention is characterized in that a standard driving force distribution is corrected, and the driving force is controlled using the corrected driving force distribution.

Further, the detection unit in this invention detects or calculates the slope of the road on which the vehicle travels, and the controller in this invention corrects the standard driving force distribution according to the magnitude and direction of the slope. It may be configured as follows.

Further, in the present invention, the controller controls the standard driving force so that when the slope is an uphill slope of a predetermined value or more, the ratio of the driving force to the rear wheels is increased compared to the standard driving force distribution. The force distribution is corrected, and if the slope is a downward slope of a predetermined value or more, the standard driving force distribution is corrected so that the driving force distribution on the front wheel side is larger than the standard driving force distribution. It may be configured as follows.

The vehicle according to the present invention selectively sets at least a standard mode in which the driving force distribution is the standard driving force distribution, and a rear comfort mode in which pitching on the rear wheel side is suppressed more than in the standard mode. In the present invention, the controller compares the driving force distribution with the standard driving force distribution and determines the proportion of the driving force on the rear wheel side when the rear comfort mode is selected. If the driving force is distributed closer to the rear wheels and the slope is an upward slope of a predetermined value or more, the proportion of the driving force on the rear wheel side is increased compared to the driving force distribution closer to the rear wheels. The standard driving force distribution is corrected as follows, and if the slope is a downward slope of a predetermined value or more, the standard driving force distribution is corrected so that the driving force distribution on the front wheel side is larger than the standard driving force distribution. It may be configured to correct force distribution.

The vehicle to be controlled by this invention is characterized by the distribution of driving force between the front and rear wheels, that is, the distribution ratio (distribution ratio, or ratio of these driving forces) between the driving force generated by the front wheels and the driving force generated by the rear wheels. It is a four-wheel drive vehicle that can change the driving force of the front wheels and the driving force of the rear wheels independently. With such a vehicle as a control target, the vehicle control device of the present invention is capable of performing standard driving force distribution in which the driving force distribution between the front and rear wheels is set to a predetermined distribution (distribution ratio or distribution rate) in normal times. to control the vehicle's driving force. In the vehicle control device of the present invention, the standard driving force distribution is corrected depending on the vehicle running condition and running environment, such as the vehicle speed, acceleration, or slope of the running road. For example, by correcting the standard drive force distribution and increasing the distribution of drive force to the rear wheels in the front and rear wheel drive force distribution, the rear wheels of the vehicle sink into a phenomenon known as squat (or tail squat). can be suppressed. Also, for example, by correcting the standard driving force distribution and increasing the distribution of driving force on the front wheels in the front and rear wheel driving force distribution, the phenomenon of the front wheels of the vehicle lifting up is promoted (the squat on the rear wheels is further reduced). can be increased). Therefore, the behavior of the vehicle in the pitching direction can be appropriately controlled in accordance with the vehicle's running state, the running environment, and the like.

Further, in the vehicle control device of the present invention, the gradient of the running road is determined as the running condition and environment of the vehicle, and the standard The driving force distribution is corrected. Therefore, even if the road the vehicle is traveling on is not flat and has an upward or downward slope, the behavior of the vehicle can be appropriately controlled depending on the gradient of the road.

In addition, in the vehicle control device of the present invention, the slope of the road is determined as the driving condition and driving environment of the vehicle, and if the slope is an uphill slope of a predetermined value or more, the driving force distribution between the front and rear wheels is changed. The standard driving force distribution is corrected so that the distribution of the driving force on the wheel side becomes larger. When the vehicle travels on an uphill slope, by increasing the distribution of driving force to the rear wheels, squatting of the rear wheels is suppressed. As a result, the longitudinal posture of the vehicle on an uphill slope can be kept horizontal, or can be brought close to horizontal. On the other hand, if the slope of the road is a downward slope of a predetermined value or more, the standard driving force distribution is corrected so that the driving force distribution on the front wheel side in the driving force distribution between the front and rear wheels is increased. When the vehicle travels on a downhill slope, by increasing the distribution of driving force to the front wheels, the phenomenon of the front wheels lifting or floating is promoted (the squat of the rear wheels increases). As a result, the longitudinal posture of the vehicle on a downhill slope can be kept horizontal, or can be brought close to horizontal. Therefore, even if the road the vehicle is traveling on is not flat and has an uphill or downhill slope, the behavior of the vehicle is appropriately controlled to maintain a horizontal attitude according to the slope of the road. be able to.

In the vehicle control device of the present invention, the rear comfort mode, which suppresses rear wheel pitching more than the standard mode, can be selected and set according to the will of the driver or passenger of the vehicle. By selecting the rear comfort mode, the drive force distribution between the front and rear wheels becomes closer to the rear wheels, with a larger distribution of drive force towards the rear wheels compared to the standard drive force distribution. Therefore, pitching on the rear wheel side, that is, on the rear seat side, can be suppressed. Also, when this rear comfort mode is selected, the slope of the road is determined as the vehicle's driving condition and driving environment, and if the slope is an uphill slope greater than a predetermined value, the driving force is distributed between the front and rear wheels. The standard driving force distribution is corrected so that the distribution of driving force on the rear wheel side becomes larger at . Furthermore, if the slope of the road is a downward slope of a predetermined value or more, the standard driving force distribution is corrected so that the distribution of driving force on the front wheel side in the driving force distribution between the front and rear wheels is increased. Therefore, even if the road the vehicle is traveling on is not flat and has an upward or downward slope, the vehicle's behavior is adjusted appropriately to maintain a more horizontal posture depending on the slope of the road. can be controlled.

1 is a diagram for explaining a vehicle to be controlled in the present invention, and is a diagram showing an example of the configuration and control system of the vehicle. FIG. FIG. 2 is a diagram for explaining behavior (pitching, squatting) when a general vehicle starts or accelerates. The pitch angle of pitching that occurs when a typical front wheel drive vehicle (FF), rear wheel drive vehicle (FR), and four wheel drive vehicle (4WD) start or accelerate, and the drive force distribution between the front and rear wheels. FIG. 4 is a diagram for explaining a change in pitch angle when changing the pitch angle. Vertical displacement and front and rear wheel displacement when pitching occurs when a typical front wheel drive vehicle (FF), rear wheel drive vehicle (FR), or four wheel drive vehicle (4WD) starts or accelerates, respectively. FIG. 7 is a diagram for explaining the difference in vertical displacement when changing the driving force distribution. 3 is a flowchart for explaining an example of control executed by the vehicle control device of the present invention. 6 is a diagram for explaining a correction amount (correction gain) of driving force distribution when executing the control shown in the flowchart of FIG. 5. FIG.

Embodiments of the invention will be described with reference to the drawings. In addition, the embodiment shown below is only an example of the embodiment of this invention, and does not limit this invention.

A vehicle to be controlled in an embodiment of the present invention transmits output torque of a driving force source to front wheels and rear wheels, respectively, and generates driving force at each of the front wheels and rear wheels. In addition, the vehicle to be controlled in the embodiment of the present invention has a driving force distribution between the front and rear wheels, that is, a distribution ratio between the driving force generated by the front wheels and the driving force generated by the rear wheels. It is a four-wheel drive vehicle that can change the front wheel drive force and the rear wheel drive force independently. FIG. 1 shows an example of a drive system and a control system of a vehicle to be controlled in an embodiment of the present invention.

The vehicle Ve shown in FIG. 1 includes an engine (E/G) 1, a first motor (MG1) 2, a second motor (MG2) 3, and a third motor (Rr-MG) 4 as driving power sources. ing. The engine 1 , the first motor 2 , and the second motor 3 are connected to a front wheel 6 via a transaxle 5 . The third motor 4 is connected to the rear wheel 7 via a transaxle or a differential gear (not shown). Therefore, the vehicle Ve is a "hybrid vehicle" equipped with the engine 1 and motors 2, 3, and 4 as driving power sources, and is configured as a "four-wheel drive vehicle" that drives the front wheels 6 and rear wheels 7, respectively. There is. The vehicle Ve also includes a detection unit 8 that detects various data used for control, and a controller 9 that controls driving force.

The engine 1 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine that obtains power (mechanical energy) by burning fuel, and electrically controls output adjustment and operating states such as starting and stopping. It is configured as follows. In the case of a gasoline engine, the opening degree of the throttle valve, the amount of fuel supplied or injected, execution and stopping of ignition, ignition timing, etc. are electrically controlled. Further, in the case of a diesel engine, the amount of fuel injection, the timing of fuel injection, the opening degree of the throttle valve (in the EGR system), etc. are electrically controlled.

The first motor 2 and the second motor 3 each convert electrical energy into mechanical energy (or rotational energy) or convert mechanical energy (or rotational energy) into electrical energy. Both the first motor 2 and the second motor 3 are disposed coaxially with the engine 1 and are connected to the engine 1 and the front wheels 6 via the transaxle 5 so as to be capable of transmitting power. Both the first motor 2 and the second motor 3 also have a function as a generator that generates electric power by being driven in response to the torque output by the engine 1. That is, the first motor 2 and the second motor 3 are both motors having a power generation function (so-called motor generators), and are configured by, for example, a permanent magnet type synchronous motor or an induction motor. ing. A battery 13 is connected to the first motor 2 and the second motor 3 via a power control unit (PCU) 12 having an inverter 10 and a boost converter 11, respectively. Therefore, the first motor 2 or the second motor 3 can function as a generator, and the electric power generated at that time can be stored in the battery 13. Further, the electric power stored in the battery 13 can be supplied to the second motor 3 or the first motor 2, and the second motor 3 or the first motor 2 can function as an electric motor to output driving torque.

The third motor 4 converts electrical energy into mechanical energy (or rotational energy), or converts mechanical energy (or rotational energy) into electrical energy. The third motor 4 is connected to the rear wheel 7 via a differential gear (not shown) so that power can be transmitted thereto. The third motor 4 has at least a function as an electric motor that is driven by being supplied with electric power and outputs torque. Further, the third motor 4 may have a function as a generator that generates electric power by being driven by receiving torque from the outside. That is, like the first motor 2 and the second motor, the third motor 4 is a motor (so-called motor generator) having a power generation function, and is, for example, a permanent magnet synchronous motor or an induction motor. It is composed of etc. This third motor 4 is also connected to the battery 13 via the power control unit 12 described above. Therefore, the electric power stored in the battery 13 can be supplied to the third motor 4, and the third motor 4 can function as an electric motor to output driving torque. Further, the third motor 4 can be caused to function as a generator by the torque transmitted from the rear wheels 7, and the regenerated power generated at that time can be stored in the battery 13.

Furthermore, the vehicle Ve in the embodiment of the present invention is equipped with a drive mode changeover switch 14. The drive mode changeover switch 14 is manually operated by the driver or passenger of the vehicle Ve. With this drive mode changeover switch 14, the vehicle Ve can be set to at least a standard mode in which the driving force distribution between the front and rear wheels is set to a standard driving force distribution (predetermined standard driving force distribution), and It is also possible to selectively set a plurality of driving modes including a rear comfort mode for suppressing pitching of the rear seats of the vehicle Ve. In the rear comfort mode, the driving force distribution between the front and rear wheels is set to a rear wheel-oriented driving force distribution in which the ratio of the driving force to the rear wheels 7 (distribution ratio) is larger than the standard driving force distribution described above. By changing the drive force distribution between the front and rear wheels to be closer to the rear wheels, for example, the size of the squat (width or amount of sinking) that occurs when the vehicle Ve starts or accelerates can be compared with the standard drive force distribution. can be suppressed compared to Therefore, especially the comfort of the rear seats of the vehicle Ve can be improved.

The detection unit 8 is a device or device for acquiring various data and information necessary for controlling the vehicle Ve, and includes, for example, a power supply unit, a microcomputer, a sensor, an input/output interface, etc. . In particular, the detection unit 8 in the embodiment of the present invention detects various parameters for determining the driving state (and driving environment, driving conditions, etc.) of the vehicle Ve. For example, the detection unit 8 includes a vehicle speed sensor (or wheel speed sensor) 8a that detects the vehicle speed, an acceleration sensor 8b that detects the acceleration of the vehicle Ve, an engine rotation speed sensor 8c that detects the rotation speed of the engine 1, and each motor 2. , 3, and 4, and a switch sensor 8e that detects the selected position of the drive mode changeover switch 14. Note that the vehicle may include an inclination angle sensor 8f that detects the inclination angle (gradient) of the road on which the vehicle Ve travels. The inclination angle of the road can also be calculated from the longitudinal acceleration of the vehicle Ve detected by the acceleration sensor 8b. In addition, there is an accelerator opening sensor (not shown) that detects the amount of depression (or accelerator opening) of the accelerator pedal (not shown), and the depression status (ON or OFF) of the brake pedal (not shown). It has a brake switch (not shown) and the like to detect this. The detection unit 8 is electrically connected to a controller 9, which will be described later, and outputs electrical signals according to detected values or calculated values of various sensors, devices, devices, etc. as described above to the controller 9 as detection data. do.

The controller 9 is, for example, an electronic control device mainly composed of a microcomputer, and the controller 9 in the embodiment of the present invention mainly controls the operation of the driving force source (output torque) and the drive of the vehicle Ve. Control power. Various data detected or calculated by the detection section 8 described above is input to the controller 9 . The controller 9 performs calculations using various input data and pre-stored data, calculation formulas, etc. The controller 9 is configured to output the calculation result as a control command signal to control the driving force of the vehicle Ve as described above. Although FIG. 1 shows an example in which one controller 9 is provided, a plurality of controllers 9 may be provided for each device or device to be controlled or for each control content.

In general, the posture (or vehicle behavior) of a "vehicle" in the pitching direction changes as the longitudinal acceleration changes during acceleration or deceleration. For example, as shown in FIG. 2, when the "vehicle" starts or accelerates (a large acceleration occurs), the suspension of the front wheels 6 (not shown) extends and the suspension of the rear wheels 7 (not shown) increases. A so-called squat (or tail squat, or squat) occurs. When such a squat occurs, the pitch angle (the magnitude of the change in behavior in the pitching direction) is, as shown in Fig. Front wheel drive vehicles such as FF [Front engine Front drive] cars are larger. Further, as shown in FIG. 4, when a squat occurs, the spring displacement (displacement in the vertical direction) at the rear seat position is smaller in the FR vehicle than in the FF vehicle.

Therefore, in a 4WD [Four Wheel Drive] vehicle that can control and change the driving force distribution between the front and rear wheels, such as the vehicle Ve in the embodiment of the present invention, the driving force distribution between the front and rear wheels can be changed after the above-mentioned change. By distributing the driving force closer to the wheels, it is possible to suppress the spring displacement at the rear seat position when squat occurs. As shown in Fig. 4 above, by setting the driving force distribution between the front and rear wheels to a state where the rear wheels 7 are at 100%, that is, a state equivalent to that of an FR vehicle, the spring displacement at the rear seat position can be adjusted to the maximum effect. can be suppressed. The aforementioned rear comfort mode utilizes such characteristics of the vehicle Ve, and controls the driving force distribution between the front and rear wheels to be closer to the rear wheels, and adjusts the amount of displacement of the suspension of the rear wheel 7. That is, by suppressing the spring displacement at the rear seat position, the comfort of the rear seat of the vehicle Ve can be improved.

However, the driving force distribution control between the front and rear wheels in a "four-wheel drive vehicle" as described above is basically configured on the assumption that the "vehicle" is traveling on a flat road. Therefore, as described above, when the "vehicle" travels on a slope with a slope of a certain level or higher, it is no longer possible to control the driving force distribution between the front and rear wheels as accurately as usual. Therefore, the vehicle control device according to the embodiment of the present invention determines the slope of the traveling road and executes driving force distribution control corrected according to the magnitude (angle) and direction (uphill or downhill) of the slope. . A specific example of such control is shown in the flowchart of FIG.

In the flowchart of FIG. 5, first, in step S1, it is determined whether the rear comfort mode switch (SW) is turned on, that is, whether the rear comfort mode is selected with the drive mode changeover switch 14.

If the rear comfort mode switch is OFF, that is, the rear comfort mode is not selected with the drive mode changeover switch 14, and a negative determination is made in this step S1, the process proceeds to step S2.

In step S2, normal 4WD control is executed. Normal 4WD control is normal driving force distribution control that is executed in standard mode or other driving modes (not rear comfort mode). Specifically, in normal 4WD control, driving force distribution control between the front and rear wheels is executed using a predetermined "standard driving force distribution." "Standard driving force distribution" is a driving force distribution between the front and rear wheels that allows the vehicle Ve to appropriately drive in four-wheel drive mode under normal driving conditions, and is based on the results of driving experiments, simulations, etc. predetermined.

When the normal 4WD control is executed in step S2, the routine shown in the flowchart of FIG. 5 is temporarily ended.

On the other hand, if the rear comfort mode switch is ON, that is, the rear comfort mode is selected by the drive mode changeover switch 14, and the determination in step S1 is affirmative, the process proceeds to step S3.

In step S3, it is determined whether the gradient of the traveling road is greater than or equal to a certain value. Specifically, it is determined whether the slope of the traveling road is greater than or equal to a slope threshold value α. The gradient of the running road can be detected by the above-mentioned inclination angle sensor 8f. The slope of the running road is determined by the difference between the required acceleration (or target acceleration) determined from the required driving force when the vehicle Ve starts or accelerates, and the actual longitudinal acceleration (actual acceleration) detected by the acceleration sensor 8b. It can be estimated based on If the difference between the requested acceleration and the actual acceleration is greater than or equal to a predetermined value, it is determined that the road surface has a slope greater than or equal to a predetermined value. Further, it can be determined whether the running road is an uphill slope or a downhill slope depending on the sign of the difference between the requested acceleration and the actual acceleration. As shown in FIG. 6, the gradient threshold value α is a threshold value for determining the magnitude of the gradient of the traveling road and determining whether correction is necessary in the driving force distribution control. Further, the slope threshold value α is an absolute value, and a slope threshold value α on the upward slope side and a slope threshold value α on the downward slope side are set. Note that the slope threshold on the upward slope side and the slope threshold value on the downward slope side may be set to different values. The gradient threshold value α is predetermined based on the results of driving experiments, simulations, and the like.

If a negative determination is made in step S3 because the slope of the travel path is less than a certain value, specifically, the slope of the travel path is less than the slope threshold α, the process proceeds to step S4.

In step S4, "4WD control" in rear comfort mode is executed. "4WD control" in rear comfort mode is normal driving force distribution control executed in rear comfort mode. Specifically, in the "4WD control" in this rear comfort mode, front and rear wheel drive force distribution control is executed with "rear wheel-oriented drive force distribution". "Rear wheel drive force distribution" is the drive force between the front and rear wheels that allows the vehicle Ve with the rear comfort mode selected to drive appropriately in a four-wheel drive state with increased rear seat comfort under normal driving conditions. The distribution is determined in advance based on the results of driving experiments, simulations, etc., for example. As described above, in the "rear wheel-side driving force distribution", the ratio of the driving force to the rear wheels 7 is larger than that in the "standard driving force distribution".

When the "4WD control" in the rear comfort mode is executed in step S4, the routine shown in the flowchart of FIG. 5 is temporarily ended.

On the other hand, if the slope of the travel path is greater than or equal to a certain value, specifically, the slope of the travel path is greater than or equal to the slope threshold value α, and an affirmative determination is made in step S3, the process proceeds to step S5.

In step S5, it is determined whether the slope of the travel road is an uphill slope. As described above, this can be determined based on the sign of the difference between the actual acceleration detected by the acceleration sensor 8b and the required acceleration. For example, if the value obtained by subtracting the actual acceleration from the requested acceleration is greater than 0, that is, if the difference between the requested acceleration and the actual acceleration is a positive value, it can be determined that the slope of the traveling road is an uphill slope. . Furthermore, if the value obtained by subtracting the actual acceleration from the requested acceleration is smaller than 0, that is, if the difference between the requested acceleration and the actual acceleration is a negative value, it can be determined that the slope of the running road is a downward slope. .

If a positive determination is made in step S5 because the slope of the travel path is an uphill slope, the process proceeds to step S6.

In step S6, "hill climbing correction 4WD control" in the rear comfort mode is executed. The "uphill correction 4WD control" in the rear comfort mode is "4WD control" executed when the vehicle Ve travels on an uphill road in the rear comfort mode. In the "hill-climbing correction 4WD control" in this rear comfort mode, the "standard driving force distribution" is corrected so that the ratio of the driving force to the rear wheels 7 becomes larger compared to the "rear wheel-side driving force distribution", and the correction is Drive force distribution control for the front and rear wheels is executed using the determined drive force distribution. Specifically, as shown in FIG. 6, the "standard driving force distribution" is corrected by a larger correction amount (correction gain) as the magnitude (angle) of the ascending slope becomes larger. As a result, the ratio of the driving force to the rear wheels 7 becomes even larger than the ratio of the driving force to the rear wheels 7 in the "rear wheel-side driving force distribution". Therefore, the depression of the suspension of the rear wheels 7 is further reduced than in the "4WD control" in the normal rear comfort mode, which is executed on a flat road or a substantially flat road where the slope of the running road is less than the slope threshold value α. That is, the squat that occurs when the vehicle Ve starts or accelerates on an uphill road is further suppressed. As a result, the posture of the vehicle Ve in the longitudinal direction on an uphill slope can be kept horizontal, or can be brought close to horizontal.

In this step S6, when the "uphill correction 4WD control" in the rear comfort mode is executed, the routine shown in the flowchart of FIG. 5 is temporarily ended.

On the other hand, if a negative determination is made in step S5 because the slope of the running road is a downward slope, the process proceeds to step S7.

In step S7, "downhill correction 4WD control" in the rear comfort mode is executed. The "downhill correction 4WD control" in the rear comfort mode is "4WD control" executed when the vehicle Ve travels on a road with a downhill slope in the rear comfort mode. In the "downhill correction 4WD control" in this rear comfort mode, the "standard driving force distribution" is corrected so that the ratio of the driving force to the front wheels 6 becomes larger compared to the "standard driving force distribution", and the corrected Drive force distribution control is executed between the front and rear wheels. Specifically, as shown in FIG. 6, the "standard driving force distribution" is corrected with a larger correction amount (correction gain) as the magnitude (angle) of the downward slope becomes larger. As a result, the ratio of the driving force to the front wheels 6 becomes even larger than the ratio of the driving force to the front wheels 6 in the "standard driving force distribution". Therefore, the suspension of the rear wheels 7 sinks even more than in normal "4WD control" which is performed on a flat road or a nearly flat road where the slope of the running road is less than the slope threshold value α. That is, the squat that occurs when the vehicle Ve starts or accelerates on a downhill road becomes even larger. As a result, the posture of the vehicle Ve in the longitudinal direction on a downhill slope can be kept horizontal, or can be brought close to horizontal.

In this step S7, when the "downhill correction 4WD control" in the rear comfort mode is executed, the routine shown in the flowchart of FIG. 5 is temporarily ended.

As described above, according to the vehicle control device according to the embodiment of the present invention, the driving force distribution between the front and rear wheels is appropriately changed according to the driving state and driving environment of the vehicle Ve, and the behavior of the vehicle Ve is appropriately controlled. can be controlled. In particular, when the vehicle Ve travels on a road with an upward or downward slope, the attitude of the vehicle Ve can be maintained close to horizontal according to the slope of the road, thereby improving the comfort of the vehicle Ve. Can be done.

Note that the vehicle Ve to be controlled in the embodiment of the present invention is not limited to the vehicle Ve shown in FIG. 1 described above. As mentioned above, the vehicle Ve to be controlled in the embodiment of the present invention generates driving force by transmitting the output torque of the driving force source to the front wheels 6 and the rear wheels 7, respectively, and also controls the driving force distribution between the front and rear wheels. Any configuration may be used as long as it is possible to change the distribution, proportion, or distribution ratio of the driving force generated by the front wheels 6 and the rear wheels 7, respectively. For example, the vehicle Ve is equipped with a mechanism that uses an "engine (internal combustion engine)" as a driving force source and distributes the output torque of the "engine" to front wheels 6 and rear wheels 7, and can control the distribution ratio as appropriate. It may also be a "four-wheel drive vehicle." Alternatively, for example, the vehicle Ve may be an "electric vehicle" equipped with "in-wheel motors" that are independently provided in the four wheels of the front wheels 6 and the rear wheels 7.

1 Engine (driving power source: E/G)
2 First motor (driving power source: MG1)
3 Second motor (driving power source: MG2)
4 Third motor (driving power source: Rr-MG)
5 Transaxle 6 Front wheel 7 Rear wheel 8 Detection section 8a (Detection section) Vehicle speed sensor (or wheel speed sensor)
8b Acceleration sensor (of the detection section) 8c Engine speed sensor (of the detection section) 8d Motor rotation speed sensor (of the detection section) 8e Switch sensor (of the detection section) 8f Tilt angle sensor (of the detection section) 9 Controller (ECU)
10 Inverter 11 Boost converter 12 Power control unit (PCU)
13 Battery 14 Drive mode changeover switch Ve Vehicle

Claims (4)

A vehicle control device capable of generating driving force by transmitting output torque of a driving power source to front wheels and rear wheels, respectively, and changing driving force distribution between the front and rear wheels,
a detection unit that detects or calculates various parameters for determining at least one of a driving state and a driving environment of the vehicle;
a controller that controls the driving force based on the driving force distribution,
The controller includes:
Controlling the driving force with a predetermined standard driving force distribution,
The standard driving force distribution is corrected according to at least one of the driving state and the driving environment determined based on the various parameters, and the driving force is controlled using the corrected driving force distribution. Vehicle control device. The vehicle control device according to claim 1,
The detection unit detects or calculates the slope of the road on which the vehicle travels,
The controller includes:
A vehicle control device, wherein the standard driving force distribution is corrected depending on the magnitude and direction of the gradient. The vehicle control device according to claim 2,
The controller includes:
If the slope is an uphill slope of a predetermined value or more, the standard driving force distribution is corrected so that the proportion of the driving force on the rear wheel side becomes larger compared to the standard driving force distribution,
If the slope is a downward slope of a predetermined value or more, the standard driving force distribution is corrected so that the driving force distribution on the front wheel side becomes larger compared to the standard driving force distribution. control device. The vehicle control device according to claim 2,
The vehicle is capable of selectively setting at least a standard mode in which the driving force distribution is the standard driving force distribution, and a rear comfort mode in which pitching of the rear wheels is suppressed more than in the standard mode,
The controller:
When the rear comfort mode is selected,
The driving force distribution is set to a rear-wheel biased driving force distribution in which a ratio of the driving force on the rear wheel side is larger than that of the standard driving force distribution,
When the gradient is an upward gradient of a predetermined value or more, the standard driving force distribution is corrected so that a ratio of the driving force on the rear wheel side is increased as compared with the rear-wheel-biased driving force distribution,
A vehicle control device characterized in that, when the gradient is a downward gradient of a predetermined value or more, the standard driving force distribution is corrected so that the driving force distribution on the front wheel side is larger than the standard driving force distribution.

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