Vehicular controller

Abstract

To provide a vehicular controller which can correct front and rear wheel torque distribution at an inexpensive price with no addition of components.SOLUTION: A torque distribution control part 12 corrects front and rear wheel torque distribution on the basis of a voltage fluctuation of a vehicle height sensor 7. The torque distribution control part 12 calculates reference front and rear wheel torque distribution with reference to a map with a vehicle speed and an accelerator opening as a parameter to correct the calculated reference front and rear wheel torque distribution on the basis of the voltage fluctuation of the vehicle height sensor 7. The torque distribution control part 12 calculates a front and rear wheel load ratio of a front wheel and a rear wheel upon a vehicle height fluctuation on the basis of the voltage fluctuation of the vehicle height sensor 7. Further, the torque distribution control part 12 sets the reference front and rear wheel torque distribution as the corrected front and rear wheel torque distribution when the reference front and rear wheel torque distribution is equal to or lower than the front and rear wheel load ratio and corrects the reference front and rear wheel torque distribution with the front and rear wheel load ratio as an upper limit when the reference front and rear wheel torque distribution exceeds the front and rear wheel load ratio.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle control device.

Background Art

[0002] Patent Document 1 describes a traveling device including a mechanism for sensing the state above the spring of a suspension device in order to suppress changes in vehicle behavior caused by changes in the load on the spring of the suspension device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technology described in Patent Document 1, by adding a dedicated mechanism for sensing the state above the spring of the suspension device to the vehicle, torque distribution control for preventing deterioration in ride comfort is realized. Therefore, there is a problem that the cost increases as the number of added parts increases.

[0005] The present invention has been made paying attention to the above circumstances, and an object thereof is to provide a vehicle control device capable of correcting the front and rear wheel torque distribution at low cost without adding parts.

Means for Solving the Problems

[0006] The present invention is a vehicle control device mounted on a four-wheel drive vehicle including front wheels and rear wheels as drive wheels, and a vehicle height sensor used for headlamp auto leveling that adjusts the vertical irradiation range of a headlamp according to the front-rear inclination of the vehicle. The vehicle control device includes a torque distribution control unit that controls the front-rear wheel torque distribution between the front wheels and the rear wheels. The torque distribution control unit corrects the front-rear wheel torque distribution based on the voltage fluctuation of the vehicle height sensor.

Advantages of the Invention

[0007] As described above, according to the present invention, it is possible to provide a vehicle control device that can correct the front-rear wheel torque distribution at low cost without adding components.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0009] A vehicle control device according to an embodiment of the present invention is a vehicle control device mounted on a four-wheel drive vehicle including front wheels and rear wheels as drive wheels, and a vehicle height sensor used for headlamp auto leveling that adjusts the vertical irradiation range of the headlamp according to the longitudinal inclination of the vehicle. The vehicle control device is provided with a torque distribution control unit that controls the front and rear wheel torque distribution between the front wheels and the rear wheels. The torque distribution control unit corrects the front and rear wheel torque distribution based on the voltage fluctuation of the vehicle height sensor. Thus, the vehicle control device according to an embodiment of the present invention can correct the front and rear wheel torque distribution at low cost without adding components.

Example

[0010] Hereinafter, with reference to the drawings, a vehicle equipped with a vehicle control device according to an embodiment of the present invention will be described.

[0011] As shown in FIG. 1, the vehicle 1 is a four-wheel drive vehicle including front wheels 3 and rear wheels 4 as drive wheels, and a power train 2 that applies driving force to the front wheels 3 and the rear wheels 4.

[0012] The vehicle 1 includes a vehicle height sensor 7 that detects vehicle height fluctuations, and headlamp leveling actuators 8 and 9 that perform headlamp auto leveling based on the detection signal of the vehicle height sensor 7.

[0013] The vehicle height sensor 7 detects vehicle height fluctuations at the rear of the vehicle 1 and outputs a voltage signal corresponding to the vehicle height fluctuations as a detection signal. The vehicle height fluctuation refers to the amount of sinking at the rear of the vehicle where the vehicle height sensor 7 is attached. Therefore, the vehicle height sensor 7 detects changes in the attitude of the vehicle 1 around the pitch axis by detecting vehicle height fluctuations at the rear of the vehicle 1. There is a proportional relationship between the voltage fluctuation of the vehicle height sensor 7 and the vehicle height fluctuation. Since vehicle height fluctuations due to acceleration or deceleration of the vehicle 1 or an increase in the load are proportional to the load corresponding to the fluctuation, the voltage fluctuation of the vehicle height sensor 7 is proportional to the load fluctuation. For example, when the vehicle height decreases (displaces toward the sinking side) due to an increase in the load, the voltage output from the vehicle height sensor 7 decreases.

[0014] The vehicle height sensor 7 is used for the optical axis adjustment control of the headlamp auto leveling. The optical axis adjustment control of the headlamp auto leveling is a control for automatically adjusting the vertical irradiation range of the headlamps 8A and 9A according to the front-rear inclination (inclination around the pitch axis) of the vehicle 1. By performing the optical axis adjustment control of the headlamp auto leveling, it is possible to prevent glare to the surroundings by the headlamps 8A and 9A and ensure the necessary irradiation range when the front-rear inclination of the vehicle 1 changes due to the increase or decrease of passengers, the presence or absence of luggage, and acceleration or deceleration during driving.

[0015] The headlamp leveling actuator 8 adjusts the vertical optical axis of the right headlamp 8A. The headlamp leveling actuator 9 adjusts the vertical optical axis of the left headlamp 9A. Thus, in addition to the optical axis adjustment control of the headlamp auto leveling, the vehicle height sensor 7 is used for the air pressure control of an air suspension (not shown) and a load sensing valve for enhancing the braking force during loading.

[0016] The vehicle 1 includes a vehicle speed sensor 5 for detecting the vehicle speed and an accelerator opening sensor 6 for detecting the accelerator opening. The vehicle speed sensor 5 detects the vehicle speed based on the rotational speed of the front wheels 3 or the rear wheels 4. The accelerator opening sensor 6 detects the depression amount of an accelerator pedal (not shown) as the accelerator opening.

[0017] The vehicle 1 includes an ECU 10 for controlling the entire vehicle.

[0018] The ECU 10 is composed of a computer unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, and an output port.

[0019] In the ROM of the computer unit, a program for causing the computer unit to function as the ECU 10 is stored together with various constants, various maps, and the like. That is, in the computer unit, when the CPU executes the program stored in the ROM, the computer unit functions as the ECU 10 in the present embodiment.

[0020] Various sensors including a vehicle height sensor 7, a vehicle speed sensor 5, and an accelerator opening sensor 6 are connected to the input port of the ECU 10. Various controlled objects including headlamp leveling actuators 8 and 9 and a power train 2 are connected to the output port of the ECU 10.

[0021] The ECU 10 has a headlamp leveling control unit 11 (referred to as a headlight leveling control unit in the figure). The headlamp leveling control unit 11 controls the headlamp leveling actuators 8 and 9 so that the vertical optical axes of the headlamps 8A and 9A are in a predetermined state based on the voltage signal that is the detection signal of the vehicle height sensor 7.

[0022] The ECU 10 has a torque distribution control unit 12. The torque distribution control unit 12 controls the front-rear wheel torque distribution between the front wheels 3 and the rear wheels 4. The front-rear wheel torque distribution is the distribution between the torque of the front wheels 3 and the torque of the rear wheels 4.

[0023] Here, in order to prevent wheel slip, it is desirable that the front-rear wheel torque distribution be determined based on the ratio of the load on the front wheels 3 to the load on the rear wheels 4. In the present embodiment, the existing vehicle height sensor 7 used for headlamp auto-leveling outputs a voltage proportional to the load. Therefore, the output signal of the vehicle height sensor 7 can also be used to calculate the ratio of the load on the front wheels 3 to the load on the rear wheels 4.

[0024] Therefore, the torque distribution control unit 12 corrects the front and rear wheel torque distribution based on the voltage fluctuation of the vehicle height sensor 7. The torque distribution control unit 12 stores a reference front and rear wheel torque distribution calculation map using the vehicle speed and the accelerator opening as parameters. The torque distribution control unit 12 refers to the reference front and rear wheel torque distribution calculation map shown in FIG. 2, calculates the reference front and rear wheel torque distribution from the vehicle speed and the accelerator opening, and corrects the calculated reference front and rear wheel torque distribution based on the voltage fluctuation of the vehicle height sensor 7.

[0025] As shown in FIG. 2, in the reference front and rear wheel torque distribution calculation map, the reference front and rear wheel torque distribution (denoted as the reference torque distribution in the figure) with respect to the vehicle speed (denoted as the front wheel vehicle speed in the figure) based on the rotational speed of the front wheel 3 and the accelerator opening is determined. In FIG. 2, the values of the reference front and rear wheel torque distribution are omitted.

[0026] The torque distribution control unit 12 calculates the front and rear wheel load ratio between the front wheel 3 and the rear wheel 4 during vehicle height variation based on the voltage fluctuation of the vehicle height sensor 7. Then, when the reference front and rear wheel torque distribution is less than or equal to the front and rear wheel load ratio, the torque distribution control unit 12 sets the reference front and rear wheel torque distribution as the front and rear wheel torque distribution after correction. On the other hand, when the reference front and rear wheel torque distribution exceeds the front and rear wheel load ratio, the torque distribution control unit 12 corrects the reference front and rear wheel torque distribution with the front and rear wheel load ratio as the upper limit.

[0027] In this embodiment, the front and rear wheel torque distribution and the reference front and rear wheel torque distribution are the ratio of the torque of the front wheel 3 to the sum of the torque of the front wheel 3 and the torque of the rear wheel 4. The front and rear wheel load ratio is the ratio of the load of the front wheel 3 to the sum of the load of the front wheel 3 and the load of the rear wheel 4.

[0028] Next, the method for calculating the front and rear wheel torque distribution by the torque distribution control unit 12 will be described. The grip limit torque of the front wheel 3 is estimated from the front wheel load, and the grip limit torque of the rear wheel 4 is estimated from the rear wheel load. The reference front and rear wheel torque distribution calculation map in FIG. 2 is determined considering the grip limit torque.

[0029] When the vehicle height variation is 0 mm, the front-rear wheel load ratio A1 is calculated by the following formula 1 in the torque distribution control unit 12. Here, the case where the vehicle height variation is 0 mm is, for example, when the vehicle 1 is stopped, when traveling at a constant speed on a flat road, or when the vehicle is unloaded.

[0030]

Number

[0031] In formula 1, the meanings of the respective variables are as follows. A1: Front-rear wheel load ratio when stopped, traveling at a constant speed on a flat road, or unloaded Wf: Front wheel load when stopped, traveling at a constant speed on a flat road, or unloaded Wr: Rear wheel load when stopped, traveling at a constant speed on a flat road, or unloaded

[0032] When the vehicle height variation is, for example, -40 mm, the rear wheel load Wr' is calculated by the following formula 2 in the torque distribution control unit 12. Here, the case where the vehicle height variation is -40 mm is, for example, when the amount of sinking on the rear wheel side increases during uphill road driving or acceleration driving.

[0033]

Number

[0034]

Number

[0035]

Number

[0036] Here, when the value obtained from the reference front and rear wheel torque distribution calculation map in FIG. 2 is A2 or less, the front and rear wheel torque distribution is determined according to the reference front and rear wheel torque distribution calculation map. On the other hand, when the value obtained from the reference front and rear wheel torque distribution calculation map exceeds A2, the front and rear wheel torque distribution is corrected with A2 as the upper limit.

[0037] In Equation 4, the meanings of the respective variables are as follows. A2: Front and rear wheel load ratio when the rear wheel load increases Wr': Rear wheel load when the rear wheel load increases K: Proportional coefficient (calculated from the reference front and rear wheel torque distribution calculation map in FIG. 2) △Vr: Vehicle height sensor voltage fluctuation

[0038] Next, an example of the four-wheel drive system of the vehicle 1 will be described with reference to FIGS. 3, 4, and 5. In FIGS. 3, 4, and 5, the left side of the paper surface is the front of the vehicle 1, and the vehicle 1 is provided with a vehicle height sensor 7 at the position of the rear wheel 4 in the front-rear direction.

[0039] As shown in FIG. 3, the vehicle 1 may be configured as a four-wheel drive vehicle equipped with a mechanical four-wheel drive system. In FIG. 3, the vehicle 1 is provided with an engine 21, a motor 22, a multi-stage transmission 23, and a transfer 24 on the front wheel 3 side, and an electronically controlled coupling mechanism 25 on the rear wheel 4 side. Each member constituting this mechanical four-wheel drive system constitutes the power train 2 in FIG. 1.

[0040] As shown in FIG. 4, the vehicle 1 may be configured as a four-wheel drive vehicle equipped with an electric four-wheel drive system that drives the rear wheel 4 by a motor 26. In FIG. 4, the vehicle 1 is provided with an engine 21, a motor 22, and a multi-stage transmission 23 on the front wheel 3 side, and a drive motor 26 and a transmission 27 on the rear wheel 4 side. Each member constituting this electric four-wheel drive system constitutes the power train 2 in FIG. 1.

[0041] As shown in FIG. 5, the vehicle 1 may be configured as a four-wheel drive vehicle equipped with an electric four-wheel drive system that drives the front wheels 3 and the rear wheels 4 by motors 28 and 26. In FIG. 5, the vehicle 1 includes a drive motor 28 and a transmission 29 on the side of the front wheels 3, and a drive motor 26 and a transmission 27 on the side of the rear wheels 4. Each member constituting this electric four-wheel drive system constitutes the power train 2 in FIG. 1.

[0042] Note that in the configurations of FIGS. 3 and 4, the positions of the power sources may be reversed front and back. Also, in the configurations of FIGS. 4 and 5, the transmissions 27 and 29 may be omitted.

[0043] In this embodiment, with respect to the driving state of the vehicle 1 (the movement of the center of gravity during starting, acceleration / deceleration, and going up / down slopes) and the state inside the vehicle cabin (the load fluctuation due to the luggage and the number of passengers), while constantly estimating the grip limit torque of the front wheels 3 and the rear wheels 4 based on the voltage fluctuation of the vehicle height sensor 7, the front-rear wheel torque distribution can be appropriately controlled.

[0044] As described above, the vehicle control device according to this embodiment includes a torque distribution control unit 12 that controls the front-rear wheel torque distribution between the front wheels 3 and the rear wheels 4. And the torque distribution control unit 12 corrects the front-rear wheel torque distribution based on the voltage fluctuation of the vehicle height sensor 7.

[0045] Thereby, the front-rear wheel torque distribution is corrected based on the voltage fluctuation of the vehicle height sensor 7 used for the optical axis adjustment control of the headlamp auto leveling. Therefore, the front-rear wheel torque distribution can be corrected inexpensively without adding components.

[0046] In addition to this, since the front-rear wheel torque distribution is corrected based on the voltage fluctuation of the vehicle height sensor 7, response delay can be prevented, and wheel slip can be prevented beforehand.

[0047] Also, in the vehicle control device according to this embodiment, the torque distribution control unit 12 calculates a reference front-rear wheel torque distribution by referring to a map using the vehicle speed and the accelerator opening as parameters, and corrects the calculated reference front-rear wheel torque distribution based on the voltage fluctuation of the vehicle height sensor 7.

[0048] Accordingly, the reference front and rear wheel torque distribution is calculated from a map using the vehicle speed and the accelerator opening as parameters, and the front and rear wheel torque distribution is corrected based on the voltage fluctuation of the vehicle height sensor 7 used for the optical axis adjustment control of the headlamp auto leveling. Therefore, the front and rear wheel torque distribution can be corrected at low cost without adding components.

[0049] Also, the reference front and rear wheel torque distribution is calculated from a map using the vehicle speed and the accelerator opening as parameters, and the front and rear wheel torque distribution is corrected based on the voltage fluctuation of the vehicle height sensor 7. Therefore, response delay can be prevented, and wheel slip can be prevented in advance.

[0050] Also, in the vehicle control device according to the present embodiment, the torque distribution control unit 12 calculates the front and rear wheel load ratio between the front wheel 3 and the rear wheel 4 when the vehicle height changes based on the voltage fluctuation of the vehicle height sensor 7. Then, when the reference front and rear wheel torque distribution is equal to or less than the front and rear wheel load ratio, the torque distribution control unit 12 sets the reference front and rear wheel torque distribution as the front and rear wheel torque distribution after correction. When the reference front and rear wheel torque distribution exceeds the front and rear wheel load ratio, the reference front and rear wheel torque distribution is corrected with the front and rear wheel load ratio as the upper limit.

[0051] Accordingly, the front and rear wheel load ratio when the vehicle height changes is calculated based on the voltage fluctuation of the vehicle height sensor 7 used for the optical axis adjustment control of the headlamp auto leveling. When the reference front and rear wheel torque distribution is equal to or less than the front and rear wheel load ratio, the reference front and rear wheel torque distribution is set as the front and rear wheel torque distribution after correction. When the reference front and rear wheel torque distribution exceeds the front and rear wheel load ratio, the reference front and rear wheel torque distribution is corrected with the front and rear wheel load ratio as the upper limit. Therefore, the front and rear wheel torque distribution can be corrected at low cost without adding components.

[0052] Also, the front and rear wheel load ratio when the vehicle height changes is calculated. When the reference front and rear wheel torque distribution is equal to or less than the front and rear wheel load ratio, the reference front and rear wheel torque distribution is set as the front and rear wheel torque distribution after correction. When the reference front and rear wheel torque distribution exceeds the front and rear wheel load ratio, the reference front and rear wheel torque distribution is corrected with the front and rear wheel load ratio as the upper limit. Therefore, response delay can be prevented, and wheel slip can be prevented in advance.

[0053] Although embodiments of the present invention have been disclosed, it is obvious that those skilled in the art can make changes without departing from the scope of the present invention. It is intended that all such modifications and equivalents be included in the following claims.

Description of Reference Numerals

[0054] 1 Vehicle 3 Front wheel 4 Rear wheel 7 Vehicle height sensor 8A Headlamp 9A Headlamp 12 Torque distribution control unit

Claims

1. front wheels and rear wheels as drive wheels, a vehicle control device mounted on a four-wheel drive vehicle, comprising a vehicle height sensor used for headlamp auto leveling that adjusts the vertical irradiation range of a headlamp according to the longitudinal inclination of the vehicle, comprising a torque distribution control unit that controls the front-rear wheel torque distribution between the front wheel and the rear wheel, The torque distribution control unit corrects the front-rear wheel torque distribution based on the voltage fluctuation of the vehicle height sensor. A vehicle control device characterized by this.

2. The torque distribution control unit, calculates a reference front-rear wheel torque distribution by referring to a map using vehicle speed and accelerator opening as parameters, The vehicle control device according to claim 1, characterized in that the calculated reference front-rear wheel torque distribution is corrected based on the voltage fluctuation of the vehicle height sensor.

3. The torque distribution control unit, calculates the front-rear wheel load ratio between the front wheel and the rear wheel during vehicle height change based on the voltage fluctuation of the vehicle height sensor, The front-rear wheel torque distribution and the reference front-rear wheel torque distribution are the ratio of the torque of the front wheel to the sum of the torque of the front wheel and the torque of the rear wheel, The front-rear wheel load ratio is the ratio of the load of the front wheel to the sum of the load of the front wheel and the load of the rear wheel, When the reference front-rear wheel torque distribution is less than or equal to the front-rear wheel load ratio, the corrected front-rear wheel torque distribution is used as the reference front-rear wheel torque distribution, The vehicle control device according to claim 2, characterized in that when the reference front-rear wheel torque distribution exceeds the front-rear wheel load ratio, the reference front-rear wheel torque distribution is corrected with the front-rear wheel load ratio as the upper limit.

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