Vehicle running gear

Abstract

To provide a vehicle travel device which can reduce an energy amount consumed to travel an own vehicle without giving discomfort feeling to a driver of the own vehicle.SOLUTION: A vehicle travel device 10 executes autonomous acceleration / deceleration control of starting coasting control when a distance between a vehicle and a preceding vehicle 200 increases and reaches an upper limit value of a predetermined distance range, starting acceleration control when the distance with the preceding vehicle decreases and reaches a lower limit value of a predetermined distance range, and thereby autonomously controlling acceleration / deceleration of the own vehicle 100 so that the distance with the preceding vehicle is settled within the predetermined distance range. When a travel speed of the own vehicle becomes a predetermined speed or less, a travel speed of the preceding vehicle is higher than the travel speed of the own vehicle, and a difference between the travel speed of the own vehicle and the travel speed of the preceding vehicle is a predetermined speed difference or more, during execution of the coasting control, the vehicle travel device continues the coasting control until a predetermined time elapses, even when the distance with the preceding vehicle increases and reaches the upper limit value of the predetermined distance range.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] There is known a vehicle running device that executes a follow-up running control for running the host vehicle so as to follow a preceding vehicle. Also, as such a vehicle running device, there is known a vehicle running device that reduces the amount of energy consumed in running the host vehicle by causing the host vehicle to coast when decelerating the host vehicle during execution of the follow-up running control (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] In a conventional vehicle running device, when executing the follow-up running control, the longer the time for which the host vehicle coasts, the less the amount of energy consumed in running the host vehicle. On the other hand, if the time for which the host vehicle coasts becomes long, there is a possibility of giving a sense of discomfort to the operator of the host vehicle depending on the situation.

[0005] An object of the present invention is to provide a vehicle running device that can reduce the amount of energy consumed in running the host vehicle without giving a sense of discomfort to the operator of the host vehicle.

[0006] The vehicle running gear according to the present invention includes a control device that performs autonomous acceleration and deceleration control, which autonomously controls the acceleration and deceleration of the vehicle so that the distance between the vehicle and the preceding vehicle remains within the predetermined distance range. This control device starts coasting control to allow the vehicle to coast when the distance between the vehicle and the preceding vehicle decreases and reaches the lower limit of a predetermined distance range, and starts acceleration control to accelerate the vehicle when the distance between the vehicle and the preceding vehicle increases and reaches the upper limit of the predetermined distance range. Furthermore, the control device is configured to continue coasting control until a predetermined time has elapsed, even if the distance between the vehicle and the preceding vehicle increases and reaches the upper limit of the predetermined distance range, if the vehicle's speed falls below a predetermined speed during the execution of coasting control, the preceding vehicle's speed is greater than the vehicle's speed, and the difference between the vehicle's speed and the preceding vehicle's speed is greater than or equal to a predetermined speed difference.

[0007] When autonomous acceleration and deceleration control is in operation, if the preceding vehicle is frequently accelerating and decelerating, and the system is configured to initiate coasting control when the distance between the vehicle and the preceding vehicle reaches the lower limit of a predetermined distance range, and to initiate acceleration control when the distance between the vehicle and the preceding vehicle reaches the upper limit of a predetermined distance range, then coasting control and acceleration control will be frequently repeated. This would result in a large amount of energy being consumed by the vehicle's movement, and the vehicle would repeatedly move closer to and further away from the preceding vehicle, potentially causing discomfort to the vehicle's operator.

[0008] On the other hand, when the preceding vehicle is frequently accelerating and decelerating, extending the time spent in coasting control, and consequently extending the time spent in acceleration control, will prevent frequent repetition of coasting and acceleration control. This will reduce the amount of energy consumed in driving the vehicle without causing discomfort to the driver.

[0009] According to the present invention, when coasting control is being performed, if the vehicle's speed falls below a predetermined speed, the preceding vehicle's speed is greater than the vehicle's speed, and the difference between the vehicle's speed and the preceding vehicle's speed is greater than or equal to a predetermined speed difference, coasting control will continue until a predetermined time has elapsed, even if the distance between the vehicle and the preceding vehicle increases and reaches the upper limit of a predetermined distance range. Therefore, the amount of energy consumed in driving the vehicle can be reduced without causing discomfort to the vehicle's operator.

[0010] Furthermore, in the vehicle running gear according to the present invention, the acceleration control is, for example, a control that operates the internal combustion engine of the vehicle and accelerates the vehicle using the power output from the internal combustion engine. The coasting control is, for example, a control that stops the operation of the internal combustion engine and allows the vehicle to coast. In this case, the predetermined time is set to a larger value the smaller the vehicle's speed is when the distance between the vehicle and the preceding vehicle increases during the execution of the coasting control and reaches the upper limit of the predetermined distance range.

[0011] The amount of energy consumed to start the internal combustion engine when the vehicle is traveling at a low speed is greater than the amount of energy consumed to start the internal combustion engine when the vehicle is traveling at a high speed. Therefore, by reducing the number of times the internal combustion engine is started when the vehicle is traveling at a low speed, the amount of energy consumed to start the engine is reduced, and as a result, the amount of energy consumed to drive the vehicle can be reduced.

[0012] According to the present invention, the lower the driving speed of the vehicle when the distance between the vehicle and the preceding vehicle increases during coasting control and reaches the upper limit of a predetermined distance range, the larger the predetermined time is set to, and as a result, the duration for which coasting control is continued increases. Therefore, the number of times the internal combustion engine is started is reduced, and as a result, the amount of energy consumed in driving the vehicle can be further reduced.

[0013] The components of the present invention are not limited to the embodiments described below with reference to the drawings. Other objects, features, and incidental advantages of the present invention will be readily apparent from the description of the embodiments. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a diagram showing a vehicle running gear according to an embodiment of the present invention. [Figure 2] Figure 2(A) shows a scenario where there is a preceding vehicle in front of the vehicle, while Figure 2(B) shows a scenario where there is no preceding vehicle in front of the vehicle. [Figure 3] Figure 3 is a flowchart showing the routine executed by a vehicle running device according to an embodiment of the present invention. [Figure 4] Figure 4 is a flowchart showing the routine executed by a vehicle running device according to an embodiment of the present invention. [Figure 5] Figure 5 is a flowchart showing the routine executed by a vehicle running device according to an embodiment of the present invention. [Figure 6] Figure 6(A) shows a scenario where there is a preceding vehicle in front of the vehicle and a following vehicle behind the vehicle, while Figure 6(B) shows a scenario where there is no preceding vehicle in front of the vehicle and a following vehicle behind the vehicle. [Modes for carrying out the invention]

[0015] Hereinafter, a vehicle running device according to an embodiment of the present invention will be described with reference to the drawings. As shown in Figure 1, the vehicle running device 10 according to an embodiment of the present invention is mounted on the vehicle 100. Hereinafter, the vehicle running device 10 will be described using the case where the operator of the vehicle 100 is a person who is riding in the vehicle 100 and driving the vehicle 100 (i.e., the driver of the vehicle 100) as an example.

[0016] However, the operator of the vehicle 100 may be a person who operates the vehicle 100 remotely without riding in the vehicle 100 (i.e., a remote operator of the vehicle 100). If the operator of the vehicle 100 is a remote operator, the vehicle running gear 10 is installed on the vehicle 100 and on the remote control equipment installed outside the vehicle 100 for remote operation of the vehicle 100, and the functions of the vehicle running gear 10 described below are shared between the vehicle running gear 10 installed on the vehicle 100 and the vehicle running gear 10 installed on the remote control equipment.

[0017] The vehicle running gear 10 is equipped with an ECU (Electronic Control Unit) 90. The ECU 90 mainly consists of a microcomputer. The microcomputer includes a CPU, ROM, RAM, non-volatile memory, and interfaces. The CPU is configured to perform various functions by executing instructions, programs, or routines stored in the ROM. In this example, the vehicle running gear 10 is equipped with one ECU, but as will be described later, it may be equipped with multiple ECUs and configured to have each of the ECUs perform the various processes described later.

[0018] The vehicle running gear 10 performs autonomous acceleration and deceleration control as an automatic driving control. Autonomous acceleration and deceleration control is a control that drives the vehicle 100 by autonomously controlling the drive unit 20 and the braking unit 30 to accelerate and decelerate the vehicle 100, and in this example, it is inter-vehicle distance control and driving speed control. In this example, the drive unit 20 is equipped with an internal combustion engine 21 and a motor 22, and the braking unit 30 is equipped with a hydraulic brake unit 31.

[0019] Inter-vehicle distance control is a control function that is executed when a preceding vehicle 200 is present in front of the vehicle 100, as shown in Figure 2(A). It is an autonomous acceleration / deceleration control that autonomously accelerates or decelerates the vehicle 100 based on the target inter-vehicle distance Dtgt.

[0020] The preceding vehicle 200 is another vehicle traveling in front of the host vehicle 100 and is another vehicle traveling within a predetermined distance (preceding vehicle determination distance Dth) from the host vehicle 100. The vehicle traveling device 10 detects the preceding vehicle 200 based on the surrounding detection information IS described later.

[0021] Furthermore, the target inter-vehicle distance Dtgt is the inter-vehicle distance D set by the driver as a control target for inter-vehicle distance control. The inter-vehicle distance D is the distance between the host vehicle 100 and the preceding vehicle 200. The vehicle traveling device 10 acquires the inter-vehicle distance D based on the surrounding detection information IS described later.

[0022] On the other hand, as shown in (B) of FIG. 2, the traveling speed control is control executed when there is no preceding vehicle 200 in front of the host vehicle 100, and is self-accelerating / decelerating control for autonomously accelerating and decelerating the host vehicle 100 based on the set speed Vset. The set speed Vset is the traveling speed (host vehicle speed Vego) of the host vehicle 100 set by the driver as a control target for traveling speed control. Incidentally, the vehicle traveling device 10 acquires the host vehicle speed Vego by the vehicle speed detection device 40.

[0023] Next, the operation of the vehicle traveling device 10 will be described more specifically. The vehicle traveling device 10 executes the routine shown in FIG. 3 at a predetermined calculation cycle. When the vehicle traveling device 10 starts processing from step S300 of the routine shown in FIG. 3, it advances the processing to step S305 and determines whether the self-accelerating / decelerating control execution condition C0 is satisfied. The self-accelerating / decelerating control execution condition C0 is a condition indicating that execution of the self-accelerating / decelerating control is required. The driver can request the vehicle traveling device 10 to execute the self-accelerating / decelerating control by operating the self-accelerating / decelerating control request operator 51 (travel support button).

[0024] If the vehicle running gear 10 determines "Yes" in step S305, it proceeds to step S310 to determine whether the first condition C1 is met. The first condition C1 is that the execution of the second autonomous acceleration / deceleration control (economy driving control) is not requested. The driver can request the vehicle running gear 10 to execute the second autonomous acceleration / deceleration control by operating the second autonomous acceleration / deceleration control request operator 52 (economy driving button). In this example, the second autonomous acceleration / deceleration control is the second inter-vehicle distance control and the second driving speed control, which will be described later.

[0025] If the vehicle running device 10 determines "Yes" in step S310, it proceeds to step S315 to determine whether or not a preceding vehicle 200 exists. The vehicle running device 10 determines whether or not a preceding vehicle 200 exists based on the surrounding detection information IS.

[0026] The surrounding detection information IS is information provided by the surrounding information detection device 60. In this example, the surrounding information detection device 60 includes a radar sensor 61 and a camera sensor 62. The surrounding information detection device 60 provides the vehicle driving system 10 with surrounding information (radar detection information) acquired by the radar sensor 61 as surrounding detection information IS. The surrounding information detection device 60 also provides the vehicle driving system 10 with surrounding image data (image information) acquired by the camera sensor 62 as surrounding detection information IS.

[0027] If the vehicle running device 10 determines "Yes" in step S320, it proceeds to step S320 to perform the first inter-vehicle distance control, and then proceeds to step S395 to terminate the processing of this routine.

[0028] The first inter-vehicle distance control is a control that maintains the inter-vehicle distance D at a target inter-vehicle distance Dtgt, and in this example, it is one of the first autonomous acceleration / deceleration controls. More specifically, the first inter-vehicle distance control is a control that autonomously controls the drive unit 20 and the braking unit 30 to accelerate and decelerate the vehicle 100 so that the inter-vehicle distance D is maintained at a target inter-vehicle distance Dtgt. Therefore, the first inter-vehicle distance control is a so-called follow-me driving control or adaptive cruise control.

[0029] On the other hand, if the vehicle running gear 10 determines "No" in step S315, it proceeds to step S325 to execute the first running speed control, and then proceeds to step S395 to terminate the processing of this routine.

[0030] The first driving speed control is a control that maintains the vehicle speed Vego at a set speed Vset, and in this example, it is one of the first autonomous acceleration / deceleration controls. More specifically, the first driving speed control is an autonomous acceleration / deceleration control that accelerates or decelerates the vehicle 100 by autonomously controlling the drive unit 20 and the braking unit 30 so that the vehicle speed Vego is maintained at the set speed Vset. Therefore, the first driving speed control is a so-called constant speed driving control or cruise control.

[0031] Furthermore, if the vehicle running gear 10 determines "No" in step S310, it proceeds to step S330 to determine whether or not a preceding vehicle 200 exists. That is, if the first condition C1 is not met in step S310, and therefore the second condition C2, which states that the execution of the second autonomous acceleration / deceleration control (economy driving control) is required, is met, the vehicle running gear 10 proceeds to step S330 to determine whether or not a preceding vehicle 200 exists.

[0032] If the vehicle running device 10 determines "Yes" in step S330, it proceeds to step S335 and executes the routine shown in Figure 4, as described later, to perform the second inter-vehicle distance control, and then proceeds to step S395 to terminate the processing of this routine.

[0033] The second inter-vehicle distance control is generally an autonomous acceleration / deceleration control that autonomously controls the acceleration and deceleration of the vehicle 100 so that the distance between the vehicle 100 and the preceding vehicle 200 (inter-vehicle distance D) remains within the predetermined distance range Rd. This is achieved by starting coasting control to allow the vehicle 100 to coast when the distance between the vehicle 100 and the preceding vehicle 200 (inter-vehicle distance D) increases and reaches the upper limit of a predetermined distance range Rd (upper limit distance Dupper), and starting acceleration control to accelerate the vehicle 100 when the distance between the vehicle 100 and the preceding vehicle 200 (inter-vehicle distance D) decreases and reaches the lower limit of the predetermined distance range Rd (lower limit distance Dlower).

[0034] In other words, the second inter-vehicle distance control is generally a control that maintains the inter-vehicle distance D within a predetermined distance range Rd that includes the target inter-vehicle distance Dtgt. When the inter-vehicle distance D increases and reaches the upper limit of the predetermined distance range Rd (upper distance Dupper), optimal acceleration control is performed, and when the inter-vehicle distance D decreases and reaches the lower limit of the predetermined distance range Rd (lower distance Dlower), coasting control is performed.

[0035] On the other hand, if the vehicle running device 10 determines "No" in step S330, it proceeds to step S340 to execute the second running speed control, and then proceeds to step S395 to temporarily terminate the processing of this routine.

[0036] The second speed control is a control that maintains the vehicle speed Vego within a predetermined speed range Rv, including the set speed Vset. When the vehicle speed Vego decreases and reaches the lower limit of the predetermined speed range Rv (lower speed Vlower), the drive unit 20 is controlled to accelerate the vehicle 100. When the vehicle speed Vego increases and reaches the upper limit of the predetermined speed range Rv (upper speed Vupper), the drive unit 20 is controlled to decelerate the vehicle 100.

[0037] In particular, the second speed control is a control system that accelerates the vehicle 100 by executing optimal acceleration control when the vehicle speed Vego decreases and reaches the lower limit speed Vlower, and decelerates the vehicle 100 by executing coasting control when the vehicle speed Vego increases and reaches the upper limit speed Vupper.

[0038] Optimal acceleration control is a control that controls the drive unit 20 so that power is output from the drive unit 20 with the highest energy efficiency, and in particular, a control that operates the internal combustion engine 21 at the optimal operating point (or an operating point near the optimal operating point).

[0039] On the other hand, coasting control is a control that controls the drive unit 20 so that the vehicle 100 travels by coasting.

[0040] Furthermore, if the vehicle running device 10 determines "No" in step S305, it proceeds directly to step S395 and terminates the processing of this routine.

[0041] Next, the routine shown in Figure 4 will be explained. When the vehicle running device 10 proceeds to step S335 of the routine shown in Figure 3, it starts processing from step S400 of the routine shown in Figure 4, proceeds to step S405, and determines whether the inter-vehicle distance D is greater than or equal to the upper limit distance Dupper.

[0042] If the vehicle running gear 10 determines "Yes" in step S405, it proceeds to step S410 to determine whether (1) the vehicle speed Vego is greater than the driving speed of the preceding vehicle 200 (preceding vehicle speed Vfwd), (2) the driving speed difference ΔV is greater than or equal to a predetermined speed difference (first speed difference ΔV1), and (3) the value of the optimal acceleration control execution flag Xa is "1". The driving speed difference ΔV is the absolute value of the difference between the vehicle speed Vego and the driving speed of the preceding vehicle 200 (preceding vehicle speed Vfwd). The value of the optimal acceleration control execution flag Xa is set to "1" when optimal acceleration control is being executed.

[0043] If the vehicle running gear 10 determines "Yes" in step S410, it proceeds to step S415 to perform coasting control, and then proceeds to step S495 to terminate the processing of this routine.

[0044] On the other hand, if the vehicle running gear 10 determines "No" in step S410, it proceeds to step S420 and determines whether (1) the vehicle speed Vego is less than or equal to the lower limit speed Vlower, (2) the preceding vehicle speed Vfwd is greater than the vehicle speed Vego, (3) the driving speed difference ΔV is less than or equal to a predetermined speed difference (second speed difference ΔV2), and (4) the value of the coasting control execution flag Xd is "1". The value of the coasting control execution flag Xd is set to "1" when coasting control is being performed.

[0045] Furthermore, the condition in step S420 may be amended to include the condition that there are no following vehicles 300. As shown in Figure 6, a following vehicle 300 is another vehicle traveling behind the own vehicle 100 and traveling within a predetermined distance (following vehicle determination distance) from the own vehicle 100. The vehicle driving device 10 detects the following vehicle 300 based on the surrounding detection information IS.

[0046] If the vehicle running gear 10 determines "Yes" in step S420, it proceeds to step S425 to determine whether the coasting time T is greater than or equal to a predetermined value (predetermined coasting time Tth). The coasting time T may be the time elapsed since the start of the coasting control currently being executed, or it may be the time elapsed since the first determination of "Yes" in step S420 for one preceding vehicle 200. In this example, the predetermined coasting time Tth is set to a larger value the smaller the vehicle speed Vego is when the inter-vehicle distance D increases during the execution of coasting control and reaches the upper limit distance Dupper.

[0047] If the vehicle running gear 10 determines "Yes" in step S425, it proceeds to step S430 to execute optimal acceleration control, and then proceeds to step S495 to terminate the processing of this routine.

[0048] On the other hand, if the vehicle running gear 10 determines "No" in step S425, it proceeds to step S435 to perform coasting control, and then proceeds to step S495 to terminate the processing of this routine.

[0049] Furthermore, if the vehicle running gear 10 determines "No" in step S420, it proceeds to step S435 to perform coasting control, and then proceeds to step S495 to terminate the processing of this routine.

[0050] Furthermore, if the vehicle running gear 10 determines "No" in step S405, it proceeds to step S505 shown in Figure 5, where it determines whether the inter-vehicle distance D is greater than or equal to a predetermined distance (limit distance Dlimit). The limit distance Dlimit is the minimum inter-vehicle distance D required when considering the driving safety of the vehicle 100, and is set to a value smaller than the lower limit distance Dlower.

[0051] If the vehicle running device 10 determines "Yes" in step S505, it proceeds to step S510 to determine whether the distance between vehicles D is less than or equal to the lower limit distance Dlower. If the vehicle running device 10 determines "Yes" in step S510, it proceeds to step S515 to perform coasting control, and then proceeds to step S495 of the routine shown in Figure 4 to terminate the processing of this routine.

[0052] On the other hand, if the vehicle running gear 10 determines "No" in step S510, it proceeds to step S520 to execute optimal acceleration control, and then proceeds to step S495 of the routine shown in Figure 4, and the processing of this routine is temporarily terminated.

[0053] Furthermore, if the vehicle running device 10 determines "No" in step S505, it proceeds to step S525 to perform the first inter-vehicle distance control, and then proceeds to step S495 of the routine shown in Figure 4, and the processing of this routine is temporarily terminated.

[0054] The above describes the operation of the vehicle running gear 10.

[0055] Furthermore, when the second inter-vehicle distance control is performed, if a following vehicle 300 is present as shown in Figure 6(A), the vehicle running device 10 may be configured to set a predetermined distance range Rd so that the inter-vehicle distance D becomes an appropriate distance based on the driving speed of the following vehicle 300 and / or the distance between the following vehicle 300 and the own vehicle 100.

[0056] Similarly, when the second driving speed control is performed, if a following vehicle 300 is present as shown in Figure 6(B), the vehicle running device 10 may be configured to set a predetermined speed range Rv so that the vehicle speed Vego becomes an appropriate speed based on the driving speed of the following vehicle 300 and / or the distance between the following vehicle 300 and the vehicle 100.

[0057] <Effects> During the execution of the second-stage distance control, if the preceding vehicle 200 is frequently accelerating and decelerating, and coasting control is initiated when the distance D reaches the upper limit (Dupper), and optimal acceleration control is initiated when the distance D reaches the lower limit (Dlower), then coasting control and optimal acceleration control will be frequently repeated. This would result in a large amount of energy being consumed by the vehicle 100, and the vehicle 100 would repeatedly move closer to and further away from the preceding vehicle 200, potentially causing discomfort to the driver.

[0058] On the other hand, when the preceding vehicle 200 is frequently accelerating and decelerating, extending the time spent continuously executing coasting control, and consequently extending the time spent continuously executing optimal acceleration control, will prevent frequent repetition of coasting control and optimal acceleration control. This will reduce the amount of energy consumed by the vehicle 100 without causing discomfort to the driver.

[0059] According to the vehicle running gear 10, when the vehicle speed Vego is below the lower limit speed Vlower, the preceding vehicle speed Vfwd is greater than the vehicle speed Vego, and the driving speed difference ΔV is greater than or equal to the first speed difference ΔV1, coasting control is continued until a predetermined coasting time Tth has elapsed, even if the distance between vehicles D increases and reaches the upper limit distance Dupper. Therefore, the amount of energy consumed in driving the vehicle 100 can be reduced without causing discomfort to the driver.

[0060] Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be adopted within the scope of the present invention. [Explanation of symbols]

[0061] 10...Vehicle running gear, 20...Drive system, 30...Braking system, 60...Surrounding information detection system, 61...Radar sensor, 62...Camera sensor, 90...ECU, 100...Own vehicle, 200...Preceding vehicle

Claims

1. A vehicle running gear includes a control device that performs autonomous acceleration and deceleration control, which autonomously controls the acceleration and deceleration of the vehicle so that the distance between the vehicle and the preceding vehicle remains within the predetermined distance range, by starting coasting control to allow the vehicle to coast when the distance between the vehicle and the preceding vehicle decreases and reaches the lower limit of a predetermined distance range, and starting acceleration control to accelerate the vehicle when the distance between the vehicle and the preceding vehicle increases and reaches the upper limit of the predetermined distance range. The control device is configured such that, during the execution of coasting control, if the speed of the vehicle itself falls below a predetermined speed, and the speed of the preceding vehicle is greater than the speed of the vehicle itself, and the difference between the speed of the vehicle itself and the preceding vehicle is greater than or equal to a predetermined speed difference, the coasting control will continue until a predetermined time has elapsed, even if the distance between the vehicle itself and the preceding vehicle increases and reaches the upper limit of the predetermined distance range. Vehicle running gear.

2. In the vehicle running device according to claim 1, The acceleration control described above is a control that operates the internal combustion engine of the vehicle and accelerates the vehicle using the power output from the internal combustion engine. The aforementioned coasting control is a control that stops the operation of the internal combustion engine and allows the vehicle to coast. The predetermined time is set to a larger value the lower the driving speed of the vehicle when the distance between the vehicle and the preceding vehicle increases during the execution of the coasting control and reaches the upper limit of the predetermined distance range. Vehicle running gear.

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