Vehicle control device

Abstract

To determine whether cruise control can be engaged, with an influence of an inclination of a road surface considered.SOLUTION: A vehicle includes an acceleration sensor, a vehicular speed sensor, an inclination sensor, and a control apparatus that is capable of executing calculation processing and cruise control processing. The calculation processing is for calculating travel drive power for enabling the vehicle to travel forward on the basis of a vehicular speed and an operating amount of an accelerator pedal. The cruise control processing is for controlling so that a vehicular speed is consistent with a target vehicular speed. The control apparatus executes the cruise control processing under a condition where: a difference between a maximum value of the vehicular speed and a minimum value thereof is equal to or less than a given value in a predetermined period of time; and where a sum of travel resistance calculated on the basis of the vehicular speed and inclination resistance calculated on the basis of the inclination of the road surface is equal to or higher than travel drive power.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] The control device described in Patent Document 1 is capable of executing so-called auto-cruise processing. The control device executes the auto-cruise processing when the vehicle is in a steady driving state in which the vehicle is driving at a constant speed. Specifically, the control device judges whether the vehicle speed is within a certain range with a predetermined specified value as a median, or whether the operation amount of the accelerator pedal is within a certain range with a predetermined specified value as a median. Then, the control device executes the auto-cruise processing when the above judgment result remains positive for a predetermined period of time. During the execution of the auto-cruise processing, the control device automatically controls the accelerator opening so that the difference between the target vehicle speed and the current vehicle speed becomes small. That is, during the auto-cruise processing, the control device controls the vehicle speed to be approximately constant. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-50904 A Summary of the Invention [Problem to be solved by the invention]

[0004] The control device described in Patent Document 1 does not take into account the influence of the gradient of the road surface on which the vehicle is traveling in determining whether or not to execute the auto-cruise process. Therefore, even if the driver operates the accelerator pedal with the intention of keeping the vehicle speed constant, the auto-cruise process may not be executed.

[0005] Specifically, for example, suppose that a vehicle enters a downhill road from a flat road. In this case, a force that tries to accelerate the vehicle acts due to the influence of gravity. At this time, if the vehicle speed is to be kept constant, the driver is likely to reduce the amount of operation of the accelerator pedal. However, in the case of the control device described in Patent Document 1, the auto-cruise processing may not be executed with a decrease in the amount of operation of the accelerator pedal. Also, for example, suppose that a vehicle enters an uphill road from a flat road. In this case, a force that tries to decelerate the vehicle acts due to the influence of gravity. At this time, if the vehicle speed is to be kept constant, the driver is likely to increase the amount of operation of the accelerator pedal. However, in the case of the control device described in Patent Document 1, the auto-cruise processing may not be executed with an increase in the amount of operation of the accelerator pedal. In this way, there is a risk that the auto-cruise processing may not be started at an appropriate timing according to the driver's intention based only on the amount of operation of the accelerator pedal. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention is a control device applicable to a vehicle equipped with an accelerator sensor that detects the amount of accelerator pedal operation, a vehicle speed sensor that detects the vehicle speed, and a gradient sensor that can detect the gradient of the road surface on which the vehicle is traveling, and is capable of executing a calculation process that calculates a driving force for moving the vehicle forward based on the vehicle speed and the amount of accelerator pedal operation, and an auto-cruise process that controls the vehicle speed to a constant target vehicle speed, and is a vehicle control device that executes the auto-cruise process under the condition that the difference between the maximum and minimum values ​​of the vehicle speed at a predetermined specified time is less than a predetermined value, and the sum of the running resistance calculated based on the vehicle speed and the gradient resistance calculated based on the gradient of the road surface is greater than or equal to the driving force.

[0007] According to the above configuration, the control device executes the auto-cruise process based on the gradient of the road surface the vehicle is traveling on. That is, when the vehicle is descending or ascending a slope, even if the driver's operation amount of the accelerator pedal is changed significantly, the auto-cruise process can be executed if the vehicle speed is roughly constant and there is a high possibility that the driver does not intend to accelerate. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 shows a schematic configuration of a vehicle. [Diagram 2] FIG. 2 is a flowchart of the start determination control executed by the control device. [Diagram 3] FIG. 3 is a flowchart of the start determination control executed by the control device of the modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of a vehicle equipped with a control device will be described with reference to the drawings. <Vehicle Overview> As shown in Fig. 1, the vehicle 500 has an accelerator pedal 21, a brake pedal 22, and a shift lever 23. The accelerator pedal 21 is a foot pedal for controlling the acceleration of the vehicle 500. The brake pedal 22 is a foot pedal for operating a brake device to decelerate the vehicle 500. Note that the brake device is not shown in Fig. 1. The brake device is, for example, a disc brake device.

[0010] The shift lever 23 is a lever for switching the driving state of the vehicle 500. The shift lever 23 is operated by the driver of the vehicle 500. Here, the driving state of the vehicle 500 that can be switched by the shift lever 23 is any one of parking, neutral, low gear, drive, and reverse. When the shift lever 23 is in parking or neutral, a gear for non-driving is formed. Also, when the driving state of the vehicle 500 is low gear, drive, or reverse, a gear for driving is formed. Note that the transmission that forms the gears is not illustrated in FIG. 1.

[0011] When the vehicle 500 is in a parking running state, the rotation of the wheels of the vehicle 500 is locked. When the vehicle 500 is in a neutral running state, the driving force from the driving source such as an internal combustion engine is not transmitted to the wheels. When the vehicle 500 is in a low gear or drive running state, the driving force from the driving source such as an internal combustion engine is transmitted to the wheels, and the vehicle 500 moves forward. However, when the vehicle 500 is in a low gear running state, the gear stage of the transmission is limited to the lowest gear stage. When the vehicle 500 is in a drive running state, the gear stage of the transmission is not limited. When the vehicle 500 is in a reverse running state, the driving force from the driving source such as an internal combustion engine is transmitted to the wheels, and the vehicle 500 moves backward.

[0012] The vehicle 500 has an accelerator sensor 31 , a brake sensor 32 , a lever position sensor 33 , a vehicle speed sensor 34 , and a gradient sensor 35 . The accelerator sensor 31 detects an accelerator operation amount ACC, which is the amount of operation of the accelerator pedal 21 operated by the driver of the vehicle 500. Here, the greater the amount of operation of the accelerator pedal 21 by the driver of the vehicle 500, the greater the value of the accelerator operation amount ACC. Also, when the driver of the vehicle 500 is not operating the accelerator pedal 21, the accelerator operation amount ACC becomes zero.

[0013] The brake sensor 32 detects a brake operation amount BRA, which is an operation amount of the brake pedal 22 operated by the driver of the vehicle 500. Here, the greater the operation amount of the brake pedal 22 by the user of the vehicle 500, the greater the value of the brake operation amount BRA. Also, when the user of the vehicle 500 is not operating the brake pedal 22, the brake operation amount BRA becomes zero.

[0014] The lever position sensor 33 detects a lever position LP, which is an operating position of the shift lever 23 operated by the user of the vehicle 500. The operating positions of the shift lever 23 include each of the positions of parking, neutral, low gear, drive, and reverse, corresponding to the types of driving conditions of the vehicle 500.

[0015] The vehicle speed sensor 34 detects the vehicle speed V, which is the speed of the vehicle 500. The gradient sensor 35 detects the inclination angle θ of the front and rear axles of the vehicle 500 with respect to a horizontal plane. Specifically, the gradient sensor 35 detects, for example, an upward gradient angle and a downward gradient angle. For example, the gradient sensor 35 detects an upward gradient angle as a positive inclination angle θ. Also, the gradient sensor 35 detects a downward gradient angle as a negative inclination angle θ. That is, the gradient sensor 35 can detect the gradient of the road surface on which the vehicle 500 is traveling.

[0016] The vehicle 500 is equipped with a control device 100 . The control device 100 obtains a signal indicating an accelerator operation amount ACC from an accelerator sensor 31. The control device 100 obtains a signal indicating a brake operation amount BRA from a brake sensor 32. The control device 100 obtains a signal indicating a lever position LP from a lever position sensor 33. The control device 100 obtains a signal indicating a vehicle speed V from a vehicle speed sensor 34. The control device 100 detects a signal indicating a tilt angle θ from a gradient sensor 35.

[0017] In the calculation process, the control device 100 calculates the driving force based on the accelerator operation amount ACC and the vehicle speed V. The driving force is a force for moving the vehicle 500 forward. Specifically, the control device 100 calculates the driving force to be a larger value as the accelerator operation amount ACC is larger. Also, the control device 100 calculates the driving force to be a larger value as the vehicle speed V is larger.

[0018] The control device 100 calculates the running resistance. The running resistance can be found by substituting each value into the following formula 1. (Formula 1)F=μ·g·M+(1 / 2)·ρ·Cd·S·V 2 Here, F is the rolling resistance, μ is the rolling resistance, g is the acceleration of gravity, M is the vehicle mass, ρ is the air density, Cd is the air resistance coefficient, and S is the frontal projection area.

[0019] In this embodiment, the rolling resistance μ and the air density ρ are each a predetermined constant value. The gravitational acceleration G is 9.8 m / s 2 In addition, the vehicle mass M, the air resistance coefficient Cd, and the frontal projection area S are values ​​specific to each vehicle 500.

[0020] The control device 100 calculates the grade resistance. The grade resistance is found by substituting each value into the following formula 2. Note that the grade resistance is calculated as a positive value in the case of an upward gradient angle, and as a negative value in the case of a downward gradient angle. (Formula 2) R=M×g×sinθ Here, R represents gradient resistance.

[0021] The control device 100 may be configured as a circuit including one or more processors that execute various processes according to a computer program (software). The control device 100 may also be configured as a circuit including one or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC), that execute at least a part of the various processes, or a combination thereof. The processor includes a CPU and memories such as RAM and ROM. The memory stores program codes or instructions that are configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer.

[0022] <Auto-cruise start judgment control> The control device 100 can execute auto-cruise start determination control. The control device 100 repeatedly executes the start determination control on the condition that the brake operation amount BRA is zero and the auto-cruise process is not being executed.

[0023] As shown in Fig. 2, when the control device 100 executes the start determination control, it executes the process of step S11. In step S11, the control device 100 acquires the lever position LP. Then, the control device 100 judges whether or not the lever position LP is in drive. If the above judgment is a negative judgment, the control device 100 ends the start determination control. If the above judgment is a positive judgment, the process of the control device 100 proceeds to step S12.

[0024] In step S12, the control device 100 repeatedly acquires the vehicle speed V over a predetermined time period. Then, the control device 100 calculates the difference between the maximum value Vmax and the minimum value Vmin of the vehicle speed V during the predetermined time period. Then, the control device 100 determines whether the difference between the maximum value Vmax and the minimum value Vmin is equal to or smaller than a predetermined value.

[0025] The above-mentioned predetermined time is a time sufficient to determine whether or not the driver of the vehicle 500 is driving to keep the vehicle speed V constant. The predetermined time is set in advance as, for example, several seconds to several tens of seconds. The predetermined value is set in advance as, for example, 5 kilometers per hour. If the determination in step S12 is negative, the control device 100 ends the start determination control. If the determination in step S12 is positive, the processing of the control device 100 proceeds to step S13.

[0026] In step S13, the control device 100 calculates the driving force. The control device 100 also calculates the running resistance and the grade resistance. The methods for calculating the driving force, the running resistance, and the grade resistance are as described above. The control device 100 then determines whether or not the sum of the running resistance and the grade resistance is equal to or greater than the driving force. If the above determination is negative, the control device 100 ends the start determination control. If the above determination is positive, the control device 100 proceeds to step S14.

[0027] In step S14, the control device 100 starts the auto-cruise process. After that, the control device 100 ends the start determination control. Note that, once the auto-cruise process is started, a series of auto-cruise start determination controls are not executed until the auto-cruise process ends.

[0028] During execution of the auto-cruise process, the control device 100 automatically controls the accelerator operation amount ACC, the gear ratio, and the like so that the vehicle speed V becomes a constant target vehicle speed. The target vehicle speed is set, for example, as the average value of the maximum value Vmax and the minimum value Vmin of the vehicle speed V acquired during a predetermined time in step S12.

[0029] During the execution of the auto-cruise process, the control device 100 determines whether or not the following auto-cruise termination condition is satisfied. -Lever position LP was changed from Drive to another position. The brake operation amount BRA is a positive value. The accelerator operation amount ACC is greater than zero, and the sum of the running resistance and the grade resistance is less than the driving force.

[0030] When any one of the above three termination conditions is satisfied, the control device 100 terminates the auto-cruise process being executed. That is, the vehicle 500 travels at a vehicle speed V according to the accelerator operation amount ACC and the like.

[0031] <Action of this embodiment> For example, suppose that the vehicle 500 enters a downhill road from a flat road. In this case, the vehicle 500 gradually accelerates due to the effect of gravity. At this time, suppose that the driver of the vehicle 500 reduces the accelerator operation amount ACC in an attempt to keep the vehicle speed V constant.

[0032] On the other hand, in the auto-cruise start determination control, if the determinations in steps S11 to S13 are positive, the control device 100 starts the auto-cruise process. That is, even if the accelerator operation amount ACC is reduced, the control device 100 starts the auto-cruise process if the above three determinations are positive.

[0033] <Effects of this embodiment> (1) According to the above embodiment, the control device 100 starts the auto-cruise process on the condition that the sum of the running resistance and the gradient resistance is equal to or greater than the driving force for running. In other words, the control device 100 executes the auto-cruise process while taking into account the gradient of the road surface on which the vehicle 500 is running.

[0034] Here, when the sum of the running resistance and the gradient resistance is equal to or greater than the running driving force, the force acting in the direction of moving the vehicle 500 forward is zero or negative. In other words, the vehicle 500 is either running at a constant speed or decelerating. In this case, it is highly likely that the driver of the vehicle 500 does not intend to accelerate. Therefore, even if the accelerator operation amount ACC by the driver is changed, when the vehicle speed V is approximately constant and it is highly likely that the driver of the vehicle 500 does not intend to accelerate, the auto-cruise process can be executed.

[0035] (2) According to the above embodiment, in the auto-cruise process, the control device 100 sets the average value of the maximum value Vmax and the minimum value Vmin of the vehicle speed V acquired during a predetermined time period as the target vehicle speed. In other words, the vehicle 500 can travel at a vehicle speed V close to the vehicle speed V intended by the driver of the vehicle 500.

[0036] (3) According to the above embodiment, the control device 100 executes the auto-cruise start determination control under one of the conditions that the brake operation amount BRA is zero. Here, if the brake operation amount BRA is zero, there is a high possibility that the driver of the vehicle 500 does not intend to decelerate. Therefore, even if the driver intends to decelerate, the auto-cruise start determination control and the subsequent auto-cruise processing are prevented from being executed.

[0037] (4) According to the above embodiment, the control device 100 ends the auto-cruise processing being executed under the condition that the accelerator operation amount ACC is greater than zero and the sum of the running resistance and the gradient resistance is less than the running driving force during the execution of the auto-cruise processing. When the above condition is satisfied, the force acting in the direction to move the vehicle 500 forward is positive. In other words, the vehicle 500 is accelerating. In this case, it is highly likely that the driver of the vehicle 500 intends to accelerate. Therefore, according to the above configuration, the auto-cruise processing can be ended when the driver of the vehicle 500 wants to accelerate.

[0038] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0039] In the above embodiment, the control device 100 may omit the process of step S11 in the auto-cruise start determination control. In addition, the control device 100 may execute other determination processes instead of the process of step S11 in the auto-cruise start determination control. For example, in the example shown in FIG. 3, when the control device 100 starts the auto-cruise start determination control, it first executes the process shown in step S21 instead of the process of step S11 in the above embodiment. In step S21, the control device 100 determines whether the gradient detected by the gradient sensor 35 is a downward gradient. Specifically, the control device 100 detects the inclination angle θ from the gradient sensor 35. Then, when the state in which the inclination angle θ is negative continues for a predetermined time, the control device 100 determines that the gradient detected by the gradient sensor 35 is a downward gradient. In the case of a positive determination, the process of the control device 100 proceeds to step S22. Note that in the example shown in FIG. 3, the processes of steps S22 to S24 are the same as the processes of steps S12 to S14 in the auto-cruise start determination control in the above embodiment.

[0040] According to the above configuration, the control device 100 can execute the auto-cruise process when the vehicle 500 is traveling on a downwardly sloping road surface and the sum of the running resistance and the gradient resistance is equal to or greater than the driving force for traveling. In this modified example, as in the effect of (1) above, the auto-cruise process can be executed by taking into account the gradient of the road surface on which the vehicle 500 is traveling.

[0041] In the above embodiment, the conditions for terminating the auto-cruise process are not limited to the examples in the above embodiment. For example, in the above embodiment, the conditions for terminating the auto-cruise process may include conditions other than the conditions exemplified in the above embodiment, or some of the conditions exemplified in the above embodiment may be omitted.

[0042] In the above embodiment, the conditions for executing the auto-cruise start determination control do not have to include the brake operation amount BRA being zero. For example, the driver of the vehicle 500 may operate the brake pedal 22 in an attempt to keep the vehicle speed V constant. According to the above configuration, the auto-cruise start determination control can be executed even in this situation. Furthermore, the conditions for executing the auto-cruise start determination control may include conditions other than the conditions exemplified in the above embodiment.

[0043] In the above embodiment, the set value of the target vehicle speed during the execution of the auto-cruise process is not limited to the example of the above embodiment. For example, the control device 100 may set the maximum value Vmax of the vehicle speed V at a predetermined time or the minimum value Vmin of the vehicle speed V at a predetermined time as the target vehicle speed. In addition, the control device 100 may set an arbitrary vehicle speed V set by the driver of the vehicle 500 as the target vehicle speed.

[0044] The calculation method of the running resistance and the grade resistance is not limited to the example of the embodiment. For example, when calculating the running resistance, the rolling resistance μ and the air density ρ may be variables according to the environment in which the vehicle 500 is running. Furthermore, the formula for calculating the running resistance and the grade resistance is not limited to the example of the embodiment. [Explanation of symbols]

[0045] θ…Inclination angle ACC: Accelerator operation amount BRA: Brake operation amount 21...Accelerator pedal 22…Brake pedal 23…Shift lever 31...Accelerator sensor 32...Brake sensor 33...Lever position sensor 34...Vehicle speed sensor 35...Gradient sensor 100...Control device 500…Vehicle

Claims

1. an accelerator sensor for detecting an amount of operation of an accelerator pedal; A vehicle speed sensor for detecting a vehicle speed; A gradient sensor capable of detecting the gradient of a road surface on which a vehicle is traveling; A control device applied to the vehicle, comprising: a calculation process for calculating a driving force for moving the vehicle forward based on the vehicle speed and the operation amount of the accelerator pedal; an auto-cruise process for controlling the vehicle speed to a constant target vehicle speed; The present invention is capable of carrying out the following: a difference between a maximum value and a minimum value of the vehicle speed during a predetermined period of time is equal to or smaller than a predetermined value; The sum of the running resistance calculated based on the vehicle speed and the gradient resistance calculated based on the gradient of the road surface is equal to or greater than the driving force. The auto-cruise process is executed under the condition that Vehicle control device.

2. Furthermore, on the condition that the gradient detected by the gradient sensor is a downward gradient, Execute the auto-cruise process The vehicle control device according to claim 1 .

3. In the auto-cruise process, the target vehicle speed is set to an average value of the maximum vehicle speed and the minimum vehicle speed acquired during the predetermined period of time. The vehicle control device according to claim 1 .

4. Furthermore, under the condition that the brake pedal operation amount is zero, Execute the auto-cruise process The vehicle control device according to claim 1 .

5. During the execution of the auto-cruise process, The accelerator pedal operation amount is greater than zero and the sum of the running resistance and the gradient resistance is less than the running driving force, Terminate the currently running auto-cruise process. The vehicle control device according to claim 1 .

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