Vehicle control system

Abstract

The objective is to provide a vehicle control device that can suppress both slippage and shock. [Solution] A vehicle control device comprising: an estimation unit for estimating the load on the road surface; and a control unit for controlling the torque so that the torque increase gradient increases as the load on the road surface increases.

Description

Technical Field

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

Background Art

[0002] Techniques for controlling the torque of a vehicle to suppress slip have been developed (for example, Patent Document 1, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the responsiveness of torque to an accelerator operation is high, slip is less likely to occur. However, the shock to the passengers increases. When the responsiveness is reduced, the shock given to the passengers is alleviated, but the possibility of slip occurring is increased. In particular, slip is likely to occur when the road surface load, such as on sandy ground, is high. Therefore, an object is to provide a vehicle control device that can suppress slip and also suppress shock.

Means for Solving the Problems

[0005] The above object can be achieved by a vehicle control device including an estimation unit that estimates the load on the road surface, and a control unit that controls so that the rising gradient of torque becomes larger as the load on the road surface is higher.

Effects of the Invention

[0006] It is possible to provide a vehicle control device that can suppress slip and also suppress shock.

Brief Description of the Drawings

[0007] [Figure 1]Figure 1 is a schematic diagram of the vehicle according to this embodiment. [Figure 2] Figure 2 is a table illustrating the correspondence between load level and torque increase gradient. [Figure 3] Figure 3 is a flowchart illustrating the process in the embodiment. [Modes for carrying out the invention]

[0008] The control device of the vehicle according to this embodiment will be described below with reference to the drawings. Figure 1 is a schematic diagram of the vehicle 1 according to this embodiment. The vehicle 1 includes an internal combustion engine 10, an automatic transmission 12, two drive wheels 16, two driven wheels 18, a wheel speed sensor 19, a propeller shaft 20, a differential gear 22, a drive shaft 24, an accelerator pedal 26, an accelerator opening sensor 28, and an ECU (Electronic Control Unit) 30.

[0009] The internal combustion engine 10 is, for example, a gasoline engine or a diesel engine. The automatic transmission 12 is a stepped transmission or a continuously variable transmission. The automatic transmission 12 is connected to the internal combustion engine 10. The propeller shaft 20 extends from the automatic transmission 12 to the differential gear 22 and is connected to the automatic transmission 12 and the differential gear 22. The drive shaft 24 is connected between the differential gear 22 and the drive wheels 16 and is connected to the differential gear 22 and the drive wheels 16.

[0010] The vehicle 1 moves when the driver of the vehicle operates the accelerator pedal 26. The internal combustion engine 10 burns fuel, such as gasoline, to generate driving force. The driving force output by the internal combustion engine 10 is transmitted to the drive wheels 16 through the automatic transmission 12, propeller shaft 20, and drive shaft 24. The drive wheels 16 rotate due to the driving force, and the vehicle 1 moves.

[0011] The greater the amount the accelerator pedal 26 is pressed (accelerator opening), the greater the torque output by the internal combustion engine 10. The smaller the accelerator opening, the less torque is produced.

[0012] The accelerator pedal position sensor 28 detects the accelerator pedal position. The wheel speed sensor 19 detects the rotational speed (wheel speed) of the drive wheels 16. The wheel speed sensor 19 is provided, for example, for each drive wheel 16.

[0013] The ECU30 is the control unit of the vehicle 1 and includes a processing unit such as a CPU (Central Processing Unit), and storage devices such as RAM (Random Access Memory) and ROM (Read Only Memory). The ECU40 performs various controls by executing programs stored in the ROM and other storage devices.

[0014] The ECU 30 obtains the accelerator opening from the accelerator opening sensor 28. The ECU 30 functions as an estimation unit that estimates the load on the road surface on which the vehicle 1 is traveling. For example, the ECU 30 estimates the load as either high, medium, or low. A high load level corresponds to a high load on the road surface. A low load level corresponds to a low load. A medium load level is between high and low, and corresponds to a moderate load.

[0015] The ECU 30 functions as a control unit that controls the torque increase gradient generated by the internal combustion engine 10 according to the road load. The ECU 30 increases the torque increase gradient as the road load increases and decreases the torque increase gradient as the road load decreases. The torque increase gradient is the slope as the torque rises. More specifically, in response to an increase in accelerator opening, for example, the amount of fuel supplied to the internal combustion engine 10 and the air flow rate increase. As a result, the torque rises in response to the accelerator being pressed. The steeper the increase gradient, the faster the torque rises. The shallower the increase gradient, the more gradually the torque rises.

[0016] FIG. 2 is a table illustrating the correspondence between the road / load level and the torque increase gradient. In the example of FIG. 2, the automatic transmission 12 is, for example, a six-speed transmission. The road / load level is classified into three levels. In each gear, the torque increase gradient takes a value corresponding to the road / load level.

[0017] When the vehicle is in the first gear and the road / load level is high, the increase gradient is A11. When the vehicle is in the first gear and the road / load level is medium, the increase gradient is A12. When the vehicle is in the first gear and the road / load level is low, the increase gradient is A13. A11 is greater than A12. A12 is greater than A13. When the vehicle is in the second gear and the road / load level is high, the increase gradient is A21. When the vehicle is in the second gear and the road / load level is medium, the increase gradient is A22. When the vehicle is in the second gear and the road / load level is low, the increase gradient is A23. A21 is greater than A22 and A11. A22 is greater than A23 and A12. A23 is greater than A13. When the vehicle is in the sixth gear and the road / load level is high, the increase gradient is A61. When the vehicle is in the sixth gear and the road / load level is medium, the increase gradient is A62. When the vehicle is in the sixth gear and the road / load level is low, the increase gradient is A63.

[0018] FIG. 3 is a flowchart illustrating the processing in the embodiment. The ECU 30 determines whether the accelerator opening is maintained constant (step S10). If the determination is negative (No), the processing of FIG. 3 ends. If the determination is positive (Yes), the ECU 30 estimates the road / load (step S12). The estimation of the road / load is performed based on the driving force and the differential value (acceleration) of the wheel speed. The following is an example of the road / load estimation. The ECU 30 defines two threshold values X and Y (Y < X) for the differential value. When the differential value is greater than or equal to the threshold value X, the ECU 30 estimates that the road / load is high. When the differential value is less than the threshold value X and greater than or equal to the threshold value Y, the ECU 30 estimates that the road / load is medium. When the differential value is less than the threshold value Y, the ECU 30 estimates that the road / load is low.

[0019] The ECU 30 determines the torque increase gradient according to the level (high, medium, or low) of the road / load (step S14).

[0020] The ECU 30 determines whether or not the accelerator opening has increased (step S16). In the case of a negative determination, the ECU 30 returns to step S10. In the case of an affirmative determination, the ECU 30 increases the torque according to the rising gradient determined in step S14 (step S18). The ECU 30 determines whether or not the torque has increased to the magnitude (required value) requested by the driver (step S20). The required torque is determined according to the accelerator opening. In the case of a negative determination in step S20, the process returns to step S18. In the case of an affirmative determination, the process ends.

[0021] According to the embodiment, the ECU 30 estimates the road surface load (road load). The ECU 30 controls the rising gradient of the torque of the internal combustion engine 10 according to the road load. The greater the level of the road load, the greater the rising gradient of the torque. The responsiveness is improved, and the torque rapidly rises according to the operation of the accelerator. Even when driving on a road surface with a high road load, slip can be suppressed. The smaller the level of the road load, the smaller the rising gradient of the torque. The torque gently rises according to the operation of the accelerator. Shock to the passengers of the vehicle 1 can be suppressed.

[0022] In the example of FIG. 2, the road load is classified into three levels and the gear is six-speed. The rising gradient of the torque has a magnitude according to the level of the road load and the gear. In each gear, according to the level of the road load, the rising gradient is set to three magnitudes. In FIG. 2, the rising gradient is determined to be any one of 18 values. In the example of FIG. 2, the level of the road load is three, but the level may be three or less or three or more. The gear is six-speed, but may be six-speed or less or six-speed or more.

[0023] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of Reference Numerals

[0024] 1 Vehicle, 10 Internal combustion engine, 12 Automatic transmission, 16 Drive wheels, 18 Driven wheels, 20 Propeller shaft, 22 Differential gear, 24 Drive shaft, 26 Accelerator pedal, 28 Accelerator position sensor, 30 ECU

Claims

[Claim 1] An estimation unit that estimates the load on the road surface, A vehicle control device comprising: a control unit that controls the torque so that the torque gradient increases as the load on the road surface increases.

Images