Vehicle travel control method and apparatus

Abstract

The vehicle has a plurality of running characteristics, can select one running characteristic from among the plurality of running characteristics, has a plurality of drive force distribution characteristics for a plurality of front wheels and rear wheels, can select one drive force distribution characteristic from among the plurality of drive force distribution characteristics, in a case where the running characteristic and the drive force distribution characteristic can be independently selected, the drive force distribution characteristics for the front wheels and the rear wheels appropriate to each of the running characteristics are set in advance, and in a case where any one running characteristic is selected, the drive force distribution characteristics for the front wheels and the rear wheels appropriate to the selected running characteristic are switched based on the selected running characteristic.

Description

Technical Field

[0001] This invention relates to a method and apparatus for controlling vehicle movement. Background Technology

[0002] For example, as vehicles become more capable of controlling fuel injection quantity and ignition timing for their drive source (engine), the number of vehicles that can select multiple driving characteristics as driving modes and control the output characteristics of the drive source in a way that corresponds to the selected driving mode is gradually increasing. In vehicles equipped with an electric motor as the drive source, it is easier to control the output characteristics of the drive source. Changing the transmission shift lines is also a means of achieving multiple driving characteristics. On the other hand, vehicles capable of controlling the distribution of drive force between the front and rear wheels are also gradually increasing. Depending on the vehicle, occupants can select the characteristics of the drive force distribution between the front and rear wheels. In Patent Document 1 below, when rain is detected, a four-wheel drive mode in which the drive force distribution between the front and rear wheels is equally distributed is recommended to the occupants.

[0003] Existing technical documents Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2011-156933 Summary of the Invention

[0005] The technical problem that the invention aims to solve

[0006] However, the drive force distribution characteristics of the front and rear wheels can only be selected and switched by the occupants. For example, even if a driving characteristic suitable for slippery road surface characteristics is selected, as long as the occupants do not select a drive force distribution characteristic suitable for the front and rear wheels of that road surface, there is still a risk of drive wheel slippage and other issues that prevent the vehicle from achieving appropriate driving characteristics.

[0007] The purpose of this invention is to provide a vehicle driving control method and apparatus that can achieve appropriate vehicle driving characteristics.

[0008] Technical solutions for solving technical problems

[0009] The key point of one aspect of the present invention is that it has multiple vehicle driving characteristics, and can select one driving characteristic from the multiple driving characteristics; it has multiple front wheel and rear wheel drive force distribution characteristics, and can select one drive force distribution characteristic from the multiple drive force distribution characteristics; and it can independently select the driving characteristics and the drive force distribution characteristics. In this case, the drive force distribution characteristics of the front wheels and rear wheels suitable for each of the driving characteristics are preset. When any of the driving characteristics is selected, the drive force distribution characteristics of the front wheels and rear wheels suitable for the selected driving characteristics are switched based on the selected driving characteristics.

[0010] Invention Effects

[0011] According to one aspect of the present invention, when a driving characteristic is selected, the driving force distribution characteristic of the front and rear wheels that is suitable for the driving characteristic is switched, so that a driving characteristic suitable for, for example, slippery road surface characteristics can be achieved by the driving force distribution characteristic of the front and rear wheels that is suitable for the driving characteristic.

[0012] The objects and advantages of this invention are embodied and realized using the elements shown in the claims and combinations thereof. The foregoing general description and the following detailed description are illustrative and should be understood not to limit the invention as described in the claims. Attached Figure Description

[0013] Figure 1 This is a schematic structural diagram illustrating an example of a vehicle driving control system implementation.

[0014] Figure 2 Therefore Figure 1 A diagram illustrating the transmission shift lines based on the vehicle's driving characteristics.

[0015] Figure 3 It means by Figure 1 A flowchart illustrating an example of the computational processing performed by the transfer case controller.

[0016] Figure 4 This is a matching table indicating whether the drive mode – transfer mode – can be selected.

[0017] Figure 5 This is a control diagram for the automatic switching between drive mode and transfer mode. Detailed Implementation

[0018] Figure 1The vehicle driving control system of the illustrated embodiment is installed in a four-wheel drive vehicle capable of distributing driving force to the front wheels 1F and the rear wheels 1R. The vehicle is equipped with an engine and / or electric motor (not shown) as the driving source, and a transmission (not shown) for converting the output of this driving source into driving force corresponding to the driving speed. A transfer case 2 is provided between the transmission and the front wheels 1F and the rear wheels 1R, capable of adjusting the driving force distribution to the front wheels 1F and the rear wheels 1R. The transfer case 2 typically adjusts the driving force distribution to the front wheels 1F and the rear wheels 1R by controlling the engagement state of friction elements such as clutches. In this embodiment, the engagement state of the friction elements is controlled by a transfer actuator 3 such as an electric motor. In this vehicle, as an example, the rear wheels 1R are set as the primary drive wheels, and the front wheels 1F are set as the secondary drive wheels. When the driving force distribution to the front wheels 1F is 0, it becomes a two-wheel drive system driven only by the rear wheels 1R. Furthermore, in this embodiment, a secondary transmission is assembled within the transfer case 2. Depending on the operating state of this secondary transmission, it can be configured into a high-speed direct-drive state (4H) where the driving force distribution between the front wheels 1F and the rear wheels 1R is equally divided (50:50), and a low-speed direct-drive state (4L) where the driving force is increased compared to the high-speed direct-drive state (4H). However, the low-speed direct-drive state 4L can only be switched manually, and therefore will be omitted in the following description, which primarily focuses on the automatic control of the driving force distribution between the front wheels 1F and the rear wheels 1R. Additionally, there are vehicles where the transfer case 2 is assembled within the transmission housing; vehicles equipped with such a transfer case 2 are also subject to the vehicle driving control system of this invention.

[0019] The vehicle is equipped with a transfer mode (hereinafter referred to as T / F mode) selection unit, such as a switch (handle) 4, which allows selection of the operating state of the transfer case 2, i.e., the drive force distribution characteristics between the front wheels 1F and the rear wheels 1R. The operating state of the transfer actuator 3 is controlled by the transfer case controller 5. In this vehicle, in addition to the aforementioned high-speed direct drive (4H) mode and low-speed direct drive (4L) mode, an automatic mode can also be selected, which automatically controls the drive force distribution between the front wheels 1F and the rear wheels 1R to the optimal state. The term "mode" refers to the meaning of "style" or "state" in the English word "mode". For example, in normal driving, the automatic mode distributes drive force only to the main drive wheel, i.e., the rear wheel 1R. If the rear wheel 1R slips, for example, drive force corresponding to the slipping state is also distributed to the front wheel 1F. In addition, drive force is also distributed to the front wheel 1F when the vehicle is in a specified driving state, such as when the vehicle starts. Furthermore, in the direct drive state between the front wheels 1F and the rear wheels 1R, for example, the friction elements in the aforementioned transfer case 2 are fully engaged. These are achieved through computational processing performed within the transfer case controller 5. Therefore, the vehicle is equipped with a control input acquisition unit, such as a sensor that detects the rotational state of the wheels. Furthermore, as described above, in the following explanation, regarding T / F modes, only the high-speed direct drive (4H) mode and the automatic mode will be described.

[0020] The transfer case controller 5 is an electronic control unit (ECU) that performs the aforementioned calculations and subsequent calculations and outputs control commands to the transfer actuator. Therefore, the transfer case controller 5 includes a computer system with high processing power. This computer system, like known computer systems, includes a processor 9 with high processing power and a storage device 10 storing information such as programs and sensor signals. The processor 9 may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The storage device 10 may be a semiconductor storage device, a magnetic storage device, or an optical storage device. The storage device 10 may also include registers, a cache memory, or a memory used as main storage. The calculations performed by the transfer case controller 5 are implemented, for example, by the processor 9 executing the computer program stored in the storage device 10 of the transfer case controller 5. Alternatively, the calculations performed by the transfer case controller 5 may be executed by functional logic circuits set in general-purpose semiconductor integrated circuits. For example, the transfer case controller 5 may also have a programmable logic device such as a field-programmable gate array. In addition, the vehicle is equipped with a drive source controller that controls the operating state of the aforementioned drive source, a transmission controller that controls the operating state of the transmission, and other controllers with the same structure and function. Furthermore, the controllers can share data and communicate with each other. The vehicle also has a display 8 that displays image information such as navigation system data, and the transfer case controller 5 is connected to the display 8. A speaker is installed on the display 8, which can also output sound.

[0021] Additionally, the vehicle is equipped with a driving mode (hereinafter, D mode) selector 7 for various changes to the vehicle's driving characteristics. In D mode, such as... Figure 4As shown, the driving modes include: Standard mode, representing the typical driving characteristics of a normal vehicle; ECO mode, representing driving characteristics that reduce environmental impact; Sport mode, representing excellent handling; and SNOW mode, representing driving characteristics suitable for slippery surfaces such as snow, ice, and slush. Additionally, within the D modes, there are: Rock mode, representing driving characteristics on gravel and rocky roads; Sand mode, representing driving characteristics on sandy surfaces; Mud / Rut mode, representing driving characteristics on muddy roads, rutted roads, and riverbanks; and TOW mode, representing driving characteristics that allow for easy towing. It should be noted that gravel refers to areas with accumulated rock debris. The driving characteristics corresponding to each D mode are achieved by changing the output characteristics of the drive source and the transmission's shifting characteristics. Figure 2 This illustrates an example of the transmission shift lines in Standard, Sport, and Eco modes. In this example, compared to Standard mode, the shift lines are set to the high-speed side in Sport mode and the low-speed side in Eco mode. The result is agile driving characteristics in Sport mode and reduced environmental impact in Eco mode. These are controlled by the transmission controller. Additionally, by changing the output characteristics of the drive source, the driving force can be increased or decreased by adjusting the fuel injection quantity in the engine and the applied current in the drive motor. These are controlled by the drive source controller.

[0022] Based on the above, it can be understood that in this embodiment, D mode (driving characteristics) and T / F mode (driving force distribution characteristics) can be selected independently. On the other hand, as described later, if D mode is selected, automatic switching to T / F mode is also controlled, and the switching between the two is performed by opening and closing the automatic switching switch 6. That is, as an example, when the automatic switching switch 6 is open, automatic switching to T / F mode suitable for D mode can be performed; when the automatic switching switch 6 is closed, the linkage switching between D mode and T / F mode is not performed (making it ineffective). Figure 3 The flowchart illustrates the computational process for automatic switching to a T / F mode suitable for D mode. This computational process is executed, for example, at a predetermined sampling period. First, in step S1, the D mode selected by the D mode selector 7 and the T / F mode selected by the T / F mode selection switch 4 are read in. Next, step S2 is performed to determine whether the automatic switching switch 6 is in the on state. If the automatic switching switch 6 is in the on state, step S3 is performed; otherwise, the process returns to its original state.

[0023] In step S3, it is determined whether (since the last read) the D mode has been switched. If the D mode has been switched, proceed to step S4; otherwise, return. In step S4, refer to the D mode-T / F mode matching table (shown in the figure) and the switching control diagram (described later). Next, proceed to step S5. Based on the result of referring to the D mode-T / F mode matching table and the switching control diagram, determine whether to perform an automatic switch to the T / F mode suitable for the switched D mode. If an automatic switch to the T / F mode is performed, proceed to step S6; otherwise, return. In step S6, the T / F mode suitable for the switched D mode is read from the matching table and the switching control diagram. In step S7, the operating state of the transfer case (T / F in the figure) actuator 3 is controlled (output control signal) to achieve automatic switching to the target T / F mode. Next, proceed to step S8, display the automatic switching of the T / F mode on the display 8, and return. Alternatively, the content can be output as sound from a speaker along with the display on the display 8. According to this calculation, if there is a T / F mode suitable for the switched D mode and automatic switching to the T / F mode is allowed, then automatic switching to the T / F mode will be performed.

[0024] The above automatic switching is based on Figure 4 Matching table and Figure 5 The switching control diagram is used for this purpose. Figure 4 In the matching table, the vertical column represents D mode and the horizontal column represents T / F mode, indicating whether the combination of the two is compatible. × in the diagram indicates a mismatch, ○ indicates a match, and ◎ indicates a more recommended combination compared to the match. For example, when D mode is Rock, Sand, or Mud / Ruts, T / F mode only matches 4H mode and will not become Auto mode. On the other hand, when D mode is Eco or Sport, T / F mode only matches (recommended) Auto mode and will not become 4H mode. When D mode is Standard, Snow, or Towing, 4H mode is also suitable for T / F mode, but Auto mode is more recommended. Figure 5 The switching control diagram uses × and ○ to indicate the execution of automatic switching between T / F modes before and after the switch. ○ indicates automatic switching is performed, and × indicates it is not. The leftmost side of the diagram represents the T / F mode before the switch, the right side represents the T / F mode after the switch, and the rightmost side indicates whether automatic switching is performed. The ×, ○, and ◎ symbols in the diagram for automatic mode and 4H mode indicate… Figure 4 The combination of automatic mode and 4H mode indicates that the automatic mode marked with ○ or 4H mode (before switching) or automatic switching (after switching) T / F mode has been selected.

[0025] In this switching control diagram, when switching from a state where the 4H mode was selected as a combination of "Automatic Mode Mismatch" and "4H Mode Match" to a state where the 4H mode is matched as a combination of "Automatic Mode Mismatch" and "4H Mode Match," the system essentially continues in 4H mode, and therefore automatic switching to T / F mode is not performed. However, when switching to a combination of "Recommended Automatic Mode" and "4H Mode Match," the system automatically switches to automatic mode. (This is repeated four times in the original text.)

[0026] Furthermore, when switching from a state where the recommended automatic mode and 4H mode match are selected to a state where automatic mode does not match and 4H mode matches, the system essentially continues in 4H mode, and therefore automatic switching to T / F mode is not performed. Additionally, when switching to a state where the recommended automatic mode and 4H mode match are selected, the system automatically switches to automatic mode. Similarly, when switching to a state where the recommended automatic mode and 4H mode do not match, the system automatically switches to automatic mode. Again, when switching from a state where the recommended automatic mode and 4H mode do not match are selected, the system automatically switches to automatic mode. Again, when switching to a state where the recommended automatic mode and 4H mode match are selected, the system essentially continues in automatic mode, and therefore automatic switching to T / F mode is not performed. Again, when switching to a state where the recommended automatic mode and 4H mode do not match, the system essentially continues in automatic mode, and therefore automatic switching to T / F mode is not performed.

[0027] However, in this embodiment, even when the automatic turn signal switch 6 is on and the T / F mode automatically switches after switching to D mode, if the occupant selects a different T / F mode via the T / F mode selection switch 4, the system switches to that selected T / F mode. This considers the occupant's preference and reflects that the T / F mode selected by the occupant may be more suitable under actual road conditions. Furthermore, as mentioned above, when the automatic turn signal switch 6 is off, the automatic switching of the T / F mode accompanying the D mode switch is not performed (making it ineffective). This also considers the occupant's preference and reflects that the T / F mode selected by the occupant may be more suitable under actual road conditions.

[0028] Thus, in this vehicle driving control system, the D mode has multiple vehicle driving characteristics, and a D mode can be selected from multiple D modes. Similarly, the T / F mode has multiple front wheel 1F and rear wheel 1R drive force distribution characteristics, and a T / F mode can be selected from multiple T / F modes. When the D mode and T / F mode can be selected independently, a T / F mode suitable for each D mode is preset. When any D mode is selected, the system switches to a T / F mode suitable for that selected D mode. Therefore, driving characteristics, for example, that match slippery road surface characteristics can be achieved through drive force distribution characteristics of the front wheel 1F and rear wheel 1R that are suitable for those driving characteristics.

[0029] In addition, by enabling the switching to the appropriate T / F mode for the selected D mode to be disabled, the system can take into account the occupant's choice intentions and reflect the appropriate T / F mode selected by the occupant under actual road conditions.

[0030] In addition, by switching to a T / F mode that is suitable for the selected D mode, the system can take into account the passenger's choice and reflect the appropriate T / F mode selected by the passenger in the actual road conditions.

[0031] Furthermore, as the D mode, it includes at least two of the following modes: an energy-saving mode that reduces environmental impact, a sport mode that provides excellent handling, and a snow mode suitable for slippery surfaces. As the T / F mode, it includes an automatic mode that controls the drive force distribution between the front wheels 1F and the rear wheels 1R based on at least one of the wheel slippage state and the vehicle's driving state, and a direct-drive mode that equally distributes the drive force between the front wheels 1F and the rear wheels 1R. Thus, it is possible to achieve a combination of driving characteristics suitable for diverse driving environments and desired driving characteristics, along with drive force distribution characteristics between the front wheels 1F and the rear wheels 1R suitable for those driving characteristics.

[0032] In addition, by recommending automatic mode and turning when snow mode is selected, driving characteristics suitable for slippery road conditions can be achieved through the corresponding drive force distribution characteristics of the front wheels 1F and the rear wheels 1R.

[0033] Furthermore, multiple D modes are achieved by altering at least one of the output characteristics of the drive source and the shift line characteristics of the transmission. This allows for the selection of driving characteristics suitable for diverse driving environments and needs as modes.

[0034] In addition, by displaying and / or audibly outputting the switch between T / F modes appropriate to the selected D mode, the occupant can be made aware of the automatic switch between T / F modes.

[0035] The vehicle driving control method and apparatus involved in the embodiments have been described above. However, the present invention is not limited to the solutions described in the above embodiments, and various modifications can be made within the scope of the spirit of the present invention. For example, the matching table and switching control diagram of D mode and T / F mode in the above embodiments are only examples, and appropriate combinations and switching controls other than those described above can also be performed. In addition, the types and combinations of D mode and T / F mode are only illustrative, and D mode and T / F mode other than those described above can be appropriately set.

[0036] 1F: Front wheel; 1R: Rear wheel; 2: Transfer case; 3: Transfer actuator; 4: Transfer mode selection switch; 5: Transfer case controller (controller); 6: Automatic switch; 7: Driving mode selector; 8: Monitor.

Claims

1. A vehicle driving control method, comprising multiple vehicle driving characteristics, capable of selecting one driving characteristic from the multiple driving characteristics, having multiple front and rear wheel drive force distribution characteristics, capable of selecting one drive force distribution characteristic from the multiple drive force distribution characteristics, and capable of independently selecting the driving characteristics and the drive force distribution characteristics, characterized in that, The driving force distribution characteristics of the front and rear wheels are preset to suit each of the driving characteristics. When any of the driving characteristics is selected, the driving force distribution characteristics of the front and rear wheels are switched to suit the selected driving characteristics based on the selected driving characteristics.

2. The vehicle driving control method according to claim 1, characterized in that, It can disable the steering of the front and rear wheels to a drive force distribution characteristic suitable for the selected driving characteristics.

3. The vehicle driving control method according to claim 1, characterized in that, After switching to the drive force distribution characteristics of the front and rear wheels that are suitable for the selected driving characteristics, it is possible to select the drive force distribution characteristics of the front and rear wheels.

4. The vehicle driving control method according to claim 1, characterized in that, As the driving characteristics, it has at least two modes among an energy-saving mode that can reduce environmental impact, a sport mode with excellent handling, and a snow mode suitable for slippery surfaces. As the driving force distribution characteristics, it has an automatic mode that controls the driving force distribution between the front and rear wheels based on at least one of the wheel slippage state and the vehicle's driving state, and a direct-drive mode that distributes the driving force between the front and rear wheels equally.

5. The vehicle driving control method according to claim 4, characterized in that, If the snow mode is selected, the automatic mode is recommended and the switch should be performed.

6. The vehicle driving control method according to claim 1, characterized in that, The plurality of driving characteristics are achieved by changing at least one of the output characteristics of the drive source and the shift line characteristics of the transmission.

7. The vehicle driving control method according to claim 1, characterized in that, Display and / or sound output the steering of the front and rear wheels in accordance with the selected driving characteristics.

8. A vehicle driving control device, comprising multiple vehicle driving characteristics, capable of selecting one driving characteristic from the multiple driving characteristics, having multiple front wheel and rear wheel drive force distribution characteristics, capable of selecting one drive force distribution characteristic from the multiple drive force distribution characteristics, and capable of independently selecting the driving characteristics and the drive force distribution characteristics, characterized in that, The system includes a controller that pre-sets drive force distribution characteristics for the front and rear wheels to suit each of the aforementioned driving characteristics. When any of the aforementioned driving characteristics is selected, the controller switches to drive force distribution characteristics for the front and rear wheels that are suitable for the selected driving characteristics.

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