Vehicle control device

Abstract

To automatically start an auto-cruise control when a vehicle travels on a hill-climbing road.SOLUTION: A control device 50 includes CPU 51 which performs an auto-cruise control where a vehicle 10 travels while vehicle speed is kept being a target vehicle speed. CPU 51 starts, when amount of vehicle speed change is a change amount determination value or less in a prescribed set period and when increment of accelerator operation amount from the time of termination of the set period is within an increment range under the situation that the vehicle 10 travels on a hill-climbing road while D range is selected as the shift range, the auto-cruise control.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a control device that performs auto cruise control for running a vehicle while maintaining the vehicle speed at a target vehicle speed. This control device calculates the difference between the target accelerator opening degree calculated based on information such as the vehicle speed and the current accelerator opening degree. Then, when the difference is included in a predetermined difference range, the control device can determine that the vehicle is running on a flat road, and thus automatically starts the auto cruise control.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above control device, the auto cruise control is automatically started on the condition that the difference between the target accelerator opening degree and the current accelerator opening degree is included in a predetermined difference range. However, the predetermined difference range for determining whether the running road surface of the vehicle is a flat road may vary depending on the gradient of the running road surface. Therefore, if the predetermined difference range is set on the premise that the running road surface is a horizontal road, when the running road surface of the vehicle is an uphill road, the above difference may not reach the value within the predetermined difference range, and thus there is a possibility that the auto cruise control cannot be automatically started.

Means for Solving the Problems

[0005] The vehicle control device for solving the above problems includes an execution device that performs auto cruise control to run the vehicle while maintaining the vehicle speed at a target vehicle speed. When the vehicle is running on an uphill road with the drive range selected as the shift range, the execution device starts the auto cruise control when the change amount of the vehicle speed within a predetermined setting period is less than or equal to the change amount determination value and the increase amount of the accelerator operation amount from the end point of the setting period is within the increase amount range.

[0006] When the vehicle is running on an uphill road with the drive range selected as the shift range, if the change amount of the vehicle speed within a predetermined setting period is less than or equal to the change amount determination value and the increase amount of the accelerator operation amount from the end point of the setting period is within the increase amount range, it can be determined that the driver has the intention to run the vehicle at a constant speed. Therefore, the above vehicle control device automatically starts the auto cruise control in such a case. As a result, the above vehicle control device can automatically start the auto cruise control even when the vehicle is running on an uphill road.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0008] Hereinafter, an embodiment of the vehicle control device will be described with reference to FIGS. 1 to 4. <Configuration of Vehicle> FIG. 1 shows a vehicle 10 including a control device 50 which is an example of a vehicle control device. The vehicle 10 includes a drive device 12 and a brake device 14. The drive device 12 has a power source of the vehicle 10 such as an engine or an electric motor. The drive torque output from the drive device 12 is transmitted to a plurality of wheels 18 via a differential device 16. The brake device 14 operates to adjust the braking torque generated by the plurality of wheels 18.

[0009] The vehicle 10 includes a shift device 20 operated by a driver of the vehicle 10. The shift device 20 can select a shift range. The shift device 20 is configured to be able to select, as the shift range, a parking range (hereinafter referred to as "P range"), a neutral range (hereinafter referred to as "N range"), a drive range (hereinafter referred to as "D range"), or a reverse range (hereinafter referred to as "R range"). The shift device 20 may be a device configured to be able to select, as the shift range, a brake range (hereinafter referred to as "B range"), a manual range (hereinafter referred to as "M range"), or a sports range (also referred to as "Ds range"). Information regarding the shift range selected by the driver by operating the shift device 20 is output to the control device 50.

[0010] <Detection System of Vehicle> The vehicle 10 includes a detection system 30 that detects the driving state of the vehicle 10. The detection system 30 has a plurality of sensors. The plurality of sensors output signals according to the detected information to the control device 50. The plurality of sensors includes a vehicle speed sensor 31, an accelerator opening sensor 32, and a brake switch 33. The vehicle speed sensor 31 detects the traveling speed of the vehicle 10. The accelerator opening sensor 32 detects an accelerator operation amount which is an operation amount of an accelerator pedal by the driver. The brake switch 33 detects the presence or absence of an operation of a brake pedal by the driver. The traveling speed of the vehicle 10 based on the detection value of the vehicle speed sensor 31 is referred to as "vehicle speed SP". The accelerator operation amount based on the detection value of the accelerator opening sensor 32 is referred to as "accelerator opening AC".

[0011] The detection system 30 includes a road surface gradient detection device 35 that acquires the gradient θ of the road surface on which the vehicle 10 travels, which is the driving road surface. The road surface gradient detection device 35 may be a device that acquires the gradient θ based on, for example, the information of the driving road surface received from a navigation device, or may be a device that acquires the gradient θ estimated and calculated based on the detection values of various in-vehicle sensors. In the present embodiment, when the driving road surface is an uphill road, the gradient θ has a positive value, and when the driving road surface is a downhill road, the gradient θ has a negative value. When the driving road surface is an uphill road, the steeper the gradient of the uphill road, the larger the gradient θ becomes.

[0012] <Control device> The control device 50 includes a CPU 51 and a memory 52. The CPU 51 corresponds to the "execution device". The memory 52 stores various control programs executed by the CPU 51. The CPU 51 operates the drive device 12 and the control device 50 by executing the control program.

[0013] <Automatic start process> Referring to FIG. 2, the automatic start process, which is the flow of the process when automatically starting the auto cruise control, will be described. The CPU 51 repeatedly executes the automatic start process when the auto cruise control is not being performed. The auto cruise control is a control for driving the vehicle 10 while maintaining the vehicle speed SP at the target vehicle speed SPTr.

[0014] In step S11, the CPU 51 determines whether the D range is selected as the shift range in the shift device 20. When the D range is selected (S11: YES), the CPU 51 transfers the process to step S13. On the other hand, when a range other than the D range is selected (S11: NO), the CPU 51 temporarily ends the automatic start process. When a range other than the D range is selected, there is a possibility that the driver does not have the intention to drive the vehicle 10 at a constant speed. Therefore, the CPU 51 does not start the auto cruise control.

[0015] In step S13, the CPU 51 acquires the current vehicle speed SP. Subsequently, in step S15, the CPU 51 determines whether or not a predetermined set time TMS has elapsed since it was determined that the D range was selected in the current automatic start process. As the set time TMS, the minimum value of the time required for the driver to feel the change in the vehicle speed when the vehicle speed is changing gently or a time corresponding to the minimum value is set. For example, a time of 5 seconds or more and 15 seconds or less is set as the set time TMS. If the set time TMS has elapsed (S15: YES), the CPU 51 transfers the process to step S17. On the other hand, if the set time TMS has not yet elapsed (S15: NO), the CPU 51 transfers the process to step S13. That is, the CPU 51 monitors the transition of the vehicle speed SP during the set period, which is the period from the time when it is determined that the D range is selected until the set time TMS elapses.

[0016] In step S17, the CPU 51 determines whether or not the change amount of the vehicle speed SP during the above set period is equal to or less than a change amount determination value dSP. Specifically, the CPU 51 determines whether or not the difference between the maximum value SPmax and the minimum value SPmin of the vehicle speed SP during the above set period is equal to or less than the change amount determination value dSP. The criterion for determining whether or not the vehicle speed SP was constant during the above set period is set as the change amount determination value dSP. If the above difference is equal to or less than the change amount determination value dSP, it is regarded that the vehicle 10 was traveling at a constant speed during the set period. On the other hand, if the above difference is greater than the change amount determination value dSP, it is regarded that the vehicle speed was changing during the set period. If the above difference is equal to or less than the change amount determination value dSP (S17: YES), the CPU 51 transfers the process to step S19. On the other hand, if the above difference is greater than the change amount determination value dSP (S17: NO), the automatic start process is temporarily terminated. That is, if the above difference is greater than the change amount determination value dSP, it can be determined that the driver allows the change in the vehicle speed. Therefore, the CPU 51 does not start the auto cruise control.

[0017] In step S19, the CPU 51 determines whether the gradient θ of the driving road surface is greater than the gradient determination value θup_min. The gradient that can determine whether the driving road surface is an uphill road is set as the gradient determination value θup_min. If the gradient θ is greater than the gradient determination value θup_min, the driving road surface is regarded as an uphill road. On the other hand, if the gradient θ is less than or equal to the gradient determination value θup_min, the driving road surface is regarded as not being an uphill road. When the gradient θ is greater than the gradient determination value θup_min (S19: YES), the CPU 51 transfers the process to step S21. On the other hand, when the gradient θ is less than or equal to the gradient determination value θup_min (S19: NO), the CPU 51 temporarily terminates the automatic start process.

[0018] In step S21, the CPU 51 acquires the current accelerator opening AC as the reference accelerator opening ACB. That is, the CPU 51 acquires the accelerator opening AC at the end of the above setting period as the reference accelerator opening ACB. Subsequently, in step S23, the CPU 51 determines whether a predetermined determination time TMA has elapsed since the end of the setting period. The length of time that can determine whether the accelerator opening AC has changed due to the driver's will since the end of the setting period is set as the determination time TMA. The determination time TMA is shorter than the above setting time TMS. When the determination time TMA has elapsed (S23: YES), the CPU 51 transfers the process to step S25. On the other hand, when the determination time TMA has not elapsed (S23: NO), the CPU 51 repeats the determination in step S23 until the determination time TMA has elapsed.

[0019] In step S25, the CPU 51 determines whether the accelerator increase amount Tcon is a value within the increase amount range. The accelerator increase amount Tcon is the increase amount of the accelerator opening AC from the end of the above setting period. That is, the value obtained by subtracting the reference accelerator opening ACB from the current accelerator opening AC is the accelerator increase amount Tcon. The lower limit of the increase amount range is the increase amount lower limit value Tcon_lwr, and the upper limit of the increase amount range is the increase amount upper limit value Tcon_upr.

[0020] As the lower limit value of the increase amount Tcon_lwr, an accelerator increase amount that can determine whether the accelerator pedal has been depressed further by the driver's will is set. When the accelerator increase amount Tcon is less than the lower limit value of the increase amount Tcon_lwr, it is regarded that the accelerator pedal has not been depressed further. On the other hand, when the accelerator increase amount Tcon is greater than or equal to the lower limit value of the increase amount Tcon_lwr, it is regarded that the accelerator pedal has been depressed further.

[0021] As the upper limit value of the increase amount Tcon_upr, an accelerator increase amount that can determine whether the driver has the intention to accelerate the vehicle 10 is set. When the accelerator increase amount Tcon is greater than the upper limit value of the increase amount Tcon_upr, it is regarded that the driver has the intention to accelerate the vehicle 10. On the other hand, when the accelerator increase amount Tcon is less than or equal to the upper limit value of the increase amount Tcon_upr, it is regarded that the driver does not have the intention to accelerate the vehicle 10.

[0022] In this embodiment, the CPU 51 varies the upper limit value of the increase amount Tcon_upr according to the gradient θ of the driving road surface. Specifically, the CPU 51 sets a larger value as the upper limit value of the increase amount Tcon_upr as the gradient θ is larger, that is, as the driving road surface has a steeper gradient.

[0023] When the accelerator increase amount Tcon is greater than or equal to the lower limit value of the increase amount Tcon_lwr and less than or equal to the upper limit value of the increase amount Tcon_upr, the CPU 51 determines that the accelerator increase amount Tcon is a value within the increase amount range (S25: YES). In this case, the CPU 51 transfers the process to step S27. On the other hand, when the accelerator increase amount Tcon is less than the lower limit value of the increase amount Tcon_lwr or the accelerator increase amount Tcon is greater than the upper limit value of the increase amount Tcon_upr, the CPU 51 determines that the accelerator increase amount Tcon is not a value within the increase amount range (S25: NO). In this case, the CPU 51 temporarily ends the automatic start process. That is, when the CPU 51 can determine that the driver does not have the intention to drive the vehicle 10 at a constant speed, the auto cruise control is not started.

[0024] In step S27, the CPU 51 starts the auto cruise control. That is, the CPU 51 operates the drive device 12 and the brake device 14 so that the vehicle speed SP is maintained at the target vehicle speed SPTr. At this time, the CPU 51 sets the vehicle speed between the maximum value SPmax and the minimum value SPmin of the vehicle speed SP during the set period as the target vehicle speed SPTr. For example, the CPU 51 sets the average value of the maximum value SPmax and the minimum value SPmin as the target vehicle speed SPTr. Then, when the CPU 51 starts the auto cruise control, it ends the automatic start process.

[0025] <End determination process> Referring to FIG. 3, the end determination process, which is the flow of the process when ending the auto cruise control, will be described. The CPU 51 repeatedly executes the end determination process when starting the auto cruise control through the execution of the above automatic start process.

[0026] In step S41, the CPU 51 determines whether the range selected by the shift device 20 has been changed from the D range to another range. When the CPU 51 determines that the range has been changed from the D range to another range (S41: YES), the process proceeds to step S47. On the other hand, when the D range remains selected (S41: NO), the CPU 51 proceeds to step S43.

[0027] In step S43, the CPU 51 determines whether the driver is operating the brake pedal based on the signal of the brake switch 33. The operation of the brake pedal is referred to as "brake operation". When the CPU 51 determines that the brake operation is being performed (S43: YES), the process proceeds to step S47. On the other hand, when the CPU 51 determines that the brake operation is not being performed (S43: NO), the process proceeds to step S45.

[0028] In step S45, the CPU 51 determines whether there is a driver's acceleration request. For example, the CPU 51 determines whether there is a driver's acceleration request based on the following relational expression.

[0029] (Required driving force) > (Vehicle running resistance) + (Gravitational acceleration due to the slope of the driving road surface) The CPU 51 derives the required driving force such that the required driving force increases as the accelerator opening AC increases. The CPU 51 derives the running resistance by a well-known calculation formula based on the vehicle speed SP and the like. The CPU 51 derives the gravitational acceleration due to the slope of the driving road surface such that the value increases as the slope θ increases. When the above relational expression is satisfied, it is regarded that there is an acceleration request from the driver. On the other hand, when the above relational expression is not satisfied, it is regarded that there is no acceleration request from the driver.

[0030] When the CPU 51 determines that there is an acceleration request from the driver (S45: YES), the process proceeds to step S47. On the other hand, when the CPU 51 determines that there is no acceleration request from the driver (S45: NO), the end determination process is temporarily terminated. That is, when all of the determinations in steps S41, S43, and S45 are "NO", the CPU 51 continues the auto cruise control.

[0031] In step S47, the CPU 51 terminates the auto cruise control. That is, when the range is changed from the D range to another range, the CPU 51 can determine that the driver may have the intention of accelerating the vehicle 10, so the auto cruise control is terminated. In addition, when a braking operation is being performed, the CPU 51 has the intention of decelerating the vehicle 10, so the auto cruise control is terminated. In addition, when it is determined that there is an acceleration request from the driver, of course, the CPU 51 terminates the auto cruise control. After that, the CPU 51 ends the end determination process.

[0032] <Actions of this embodiment> Referring to FIG. 4, the actions of this embodiment will be described. As a premise, it is assumed that the vehicle 10 is running in a state where the D range is selected by the shift device 20.

[0033] In the example shown in FIG. 4, before timing t11, the vehicle 10 is traveling at a substantially constant speed as shown in FIG. 4(B) under the condition that the gradient θ of the driving road surface is less than the gradient determination value θup_min as shown in FIG. 4(A). At timing t11, the gradient θ of the driving road surface becomes greater than the gradient determination value θup_min. That is, it can be determined that the vehicle 10 is traveling on an uphill road.

[0034] When the time point when the set time TMS has elapsed from timing t11 is defined as timing t12, it is determined whether the difference between the maximum value SPmax and the minimum value SPmin of the vehicle speed SP within the set period from timing t11 to timing t12 is less than or equal to the change amount determination value dSP. When the difference is less than or equal to the change amount determination value dSP, it can be regarded that the vehicle speed is substantially constant even when the vehicle 10 is traveling on an uphill road.

[0035] In the example shown in FIG. 4, the above difference is less than or equal to the change amount determination value dSP. Therefore, when the time point when the determination time TMA has elapsed from timing t12 is defined as timing t13, it is determined whether the accelerator increase amount Tcon within the period from timing t12 to timing t13 is a value within the increase amount range. When the accelerator increase amount Tcon is a value within the increase amount range, it can be determined that the driver has the intention to keep the vehicle speed constant. Therefore, the auto cruise control is started from timing t13.

[0036] <Effects of the present embodiment> (1) When the vehicle 10 is traveling on an uphill road with the D range selected, if the change amount of the vehicle speed within a predetermined set period is less than or equal to the change amount determination value dSP and the accelerator increase amount Tcon from the end point of the set period is a value within the increase amount range, it can be determined that the driver has the intention to drive at a constant speed. Therefore, in such a case, the auto cruise control is automatically started. As a result, even when the vehicle 10 is traveling on an uphill road, the auto cruise control can be automatically started.

[0037] (2) When the driving road surface is an uphill road, the steeper the gradient, the more likely the accelerator opening AC required to suppress the decrease in vehicle speed will be large. Therefore, in the present embodiment, a larger value as the gradient of the uphill road is steeper is set as the increase amount upper limit value Tcon_upr, which is the upper limit value of the increase amount range. By varying the increase amount upper limit value Tcon_upr according to the gradient θ of the driving road surface in this way, it is possible to accurately determine whether or not the driver has the intention to drive the vehicle at a constant speed.

[0038] (3) As the target vehicle speed SPTr when automatically starting the auto cruise control, a vehicle speed between the maximum value SPmax and the minimum value SPmin of the vehicle speed SP within the set period is set. Thereby, the change in the vehicle speed SP accompanying the start of the auto cruise control can be suppressed.

[0039] <Modified Example> The above embodiment can be implemented with the following modifications. The above embodiment and the following modified examples can be implemented in combination with each other as long as they do not technically conflict.

[0040] · If the vehicle speed between the maximum value SPmax and the minimum value SPmin of the vehicle speed SP within the set period is set as the target vehicle speed SPTr when automatically starting the auto cruise control, the maximum value SPmax may be set as the target vehicle speed SPTr. Also, the minimum value SPmin may be set as the target vehicle speed SPTr.

[0041] · The vehicle speed SP at the start of the auto cruise control may be set as the target vehicle speed SPTr when automatically starting the auto cruise control. · It is not essential to vary the increase amount upper limit value Tcon_upr according to the gradient θ of the driving road surface.

[0042] · The control device 50 is not limited to one that includes a CPU and a ROM and executes software processing. That is, the control device 50 may have any of the following configurations (a) to (c). (a) The control device 50 includes one or more processors that execute various processes according to a computer program. The processor includes a CPU and memories such as a RAM and a ROM. The memory stores program codes or instructions configured to cause the CPU to execute processes. The memory, that is, the computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer.

[0043] (b) The control device 50 includes one or more dedicated hardware circuits that execute various processes. Examples of the dedicated hardware circuit include, for example, an application-specific integrated circuit, that is, an ASIC or an FPGA. Note that ASIC is an abbreviation of "Application Specific Integrated Circuit", and FPGA is an abbreviation of "Field Programmable Gate Array".

[0044] (c) The control device 50 includes a processor that executes a part of various processes according to a computer program, and a dedicated hardware circuit that executes the remaining processes of the various processes.

Explanation of Signs

[0045] 10… Vehicle, 20… Shift device, 50… Control device, 51… CPU.

Claims

1. An execution device that performs auto cruise control for running a vehicle while maintaining the vehicle speed at a target vehicle speed, The execution device, In a situation where the vehicle is running on an uphill road with the drive range selected as the shift range, when the change amount of the vehicle speed within a predetermined setting period is equal to or less than a change amount determination value and the increase amount of the accelerator operation amount from the end point of the setting period is within an increase amount range, the auto cruise control is started Vehicle control device.

2. The execution device sets, as the upper limit value of the increase amount range, a larger value as the gradient of the uphill road on which the vehicle runs is steeper The vehicle control device according to claim 1.

3. When the execution device performs the auto cruise control, as the target vehicle speed, a vehicle speed between the maximum value and the minimum value of the vehicle speed within the setting period is set The vehicle control device according to claim 1 or claim 2.

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