Display control device

Abstract

The invention provides a display control device capable of suppressing frequent switching of economic degree images. As a display device, when a value of an environmental parameter changes from a value equal to or less than a predetermined switching threshold value to a value greater than the predetermined switching threshold value during execution of follow-up travel control, the value of the environmental parameter reaches an increase-side threshold value greater than the predetermined switching threshold value, and the increase-side threshold value is greater than the increase-side threshold value. When the value of the environmental parameter changes from a value greater than the predetermined switching threshold value to a value less than or equal to the predetermined switching threshold value during execution of the follow-up travel control, an economy degree image indicating the economy degree acquired on the basis of the first evaluation value is displayed by a display device. Before the value of the environmental parameter reaches a decrease-side threshold value that is less than the prescribed switching threshold value, an economy degree image indicating the economy degree acquired on the basis of the second evaluation value is displayed by the display device.

Description

Technical Field

[0001] The present invention relates to a display control device. Background Art

[0002] A display control device is known that displays an economy image indicating the degree of economy (i.e., the degree of low energy consumption associated with the driving of the vehicle) on an instrument display. In addition, a display control device is also known that switches between different economy images for display in a case where the economy is high and a case where the economy is low. In a case where the display control device is configured so that the economy is determined to be high when the detection data detected by the sensor is below a threshold and is determined to be low when the vehicle-to-vehicle distance is greater than the threshold, if the detection data frequently increases and decreases repeatedly across the threshold, the economy image switches frequently, which may annoy the driver of the vehicle. As a technique for absorbing the frequent increase in the detection data, a method of performing Kalman filtering on the detection data is known (for example, refer to Patent Document 1). Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent No. 3380497 Summary of the Invention

[0004] However, when Kalman filtering is applied to the detection data, although the frequent switching of the economy level image can be suppressed to a certain extent, the frequent switching of the economy level image will still occur when the detection data actually increases and decreases frequently across the threshold.

[0005] An object of the present invention is to provide a display control device capable of suppressing frequent switching of economical degree images.

[0006] A display control device according to the present invention includes a control device configured to display an economy image indicating a degree of economy on a display device during execution of follow-up driving control, wherein the follow-up driving control causes the host vehicle to autonomously drive while allowing the distance between the host vehicle and a preceding vehicle to vary within a set inter-vehicle distance range. The economy indicates the degree of low energy consumption associated with the driving of the host vehicle. During execution of the follow-up driving control, the control device is configured to obtain a value of an environmental parameter, which is a parameter indicating the driving environment of the host vehicle and serves as a parameter defining the economy, obtain an evaluation value corresponding to the obtained environmental parameter value, obtain the economy based on the obtained evaluation value, and display the economy image indicating the obtained economy on the display. A first evaluation value corresponding to a value of the environmental parameter below a predetermined switching threshold and a second evaluation value corresponding to a value of the environmental parameter above the predetermined switching threshold are different values. The control device is configured to, during the execution of the follow-up driving control, when the value of the environmental parameter changes from a value below the prescribed switching threshold to a value greater than the prescribed switching threshold, and before the value of the environmental parameter reaches an increasing side threshold greater than the prescribed switching threshold, display the economy degree image representing the economy degree obtained based on the first evaluation value through the display device; and during the execution of the follow-up driving control, when the value of the environmental parameter changes from a value greater than the prescribed switching threshold to a value below the prescribed switching threshold, and before the value of the environmental parameter reaches a decreasing side threshold less than the prescribed switching threshold, display the economy degree image representing the economy degree obtained based on the second evaluation value through the display device.

[0007] According to the display control device of the present invention, even if the value of the environmental parameter frequently increases or decreases across a predetermined switching threshold during execution of follow-up driving control, the economy level is obtained based on the evaluation value before the environmental parameter value first crossed the predetermined switching threshold, and an economy level image representing the obtained economy level is displayed. Consequently, frequent switching of the economy level image can be suppressed.

[0008] In addition, in the display control device involved in the present invention, the control device can be configured to, during the execution of the follow-up driving control, when the value of the environmental parameter crosses the prescribed switching threshold from a value below the prescribed switching threshold to reach the increasing side threshold, display the economy degree image representing the economy degree obtained based on the second evaluation value through the display device; during the execution of the follow-up driving control, when the value of the environmental parameter crosses the prescribed switching threshold from a value greater than the prescribed switching threshold to reach the decreasing side threshold, display the economy degree image representing the economy degree obtained based on the first evaluation value through the display device.

[0009] According to the display control device of the present invention, when the value of the environmental parameter exceeds a predetermined switching threshold and reaches an increasing threshold, an economy level image representing the economy level obtained based on the second evaluation value is displayed. On the other hand, when the value of the environmental parameter exceeds the predetermined switching threshold and reaches a decreasing threshold, an economy level image representing the economy level obtained based on the first evaluation value is displayed. Therefore, when the value of the environmental parameter reaches the increasing threshold and when the value of the environmental parameter reaches the decreasing threshold, an economy level image representing a more accurate economy level is displayed.

[0010] In addition, in the display control device involved in the present invention, the control device can be configured to, during the execution of the follow-up driving control, when the value of the environmental parameter changes from a value below the prescribed switching threshold to a value greater than the prescribed switching threshold, before the value of the environmental parameter reaches the increasing side threshold, correct the value of the environmental parameter to a value below the prescribed switching threshold, and display the economy degree image representing the economy degree obtained based on the evaluation value corresponding to the corrected value of the environmental parameter through the display device; during the execution of the follow-up driving control, when the value of the environmental parameter changes from a value greater than the prescribed switching threshold to a value below the prescribed switching threshold, before the value of the environmental parameter reaches the decreasing side threshold, correct the value of the environmental parameter to a value greater than the prescribed switching threshold, and display the economy degree image representing the economy degree obtained based on the evaluation value corresponding to the corrected value of the environmental parameter through the display device.

[0011] According to the display control device of the present invention, it is possible to suppress frequent switching of the economy degree image by correcting the value of the environmental parameter.

[0012] In the display control device according to the present invention, the control device may be configured to store a first map and a second map for acquiring the evaluation value using the value of the environmental parameter as an independent variable. In this case, the first map is a map that sets the evaluation value corresponding to the value of the environmental parameter below the predetermined switching threshold and the evaluation value corresponding to the value of the environmental parameter above the predetermined switching threshold to the same degree, and the second map is a map that sets the evaluation value corresponding to the value of the environmental parameter below the predetermined switching threshold and the evaluation value corresponding to the value of the environmental parameter above the predetermined switching threshold to different degrees. Furthermore, the control device can be configured to, during the execution of the follow-up driving control, when the value of the environmental parameter changes from a value below the prescribed switching threshold to a value greater than the prescribed switching threshold, before the value of the environmental parameter reaches the increasing side threshold, display the economy image representing the economy through the display device, wherein the economy is obtained based on the evaluation value obtained from the first mapping with the value of the environmental parameter as the independent variable; and during the execution of the follow-up driving control, when the value of the environmental parameter changes from a value greater than the prescribed switching threshold to a value below the prescribed switching threshold, before the value of the environmental parameter reaches the decreasing side threshold, display the economy image representing the economy through the display device, wherein the economy is obtained based on the evaluation value obtained from the first mapping with the value of the environmental parameter as the independent variable.

[0013] According to the display control device of the present invention, during the execution of follow-up driving control, if the value of an environmental parameter changes from a value below a predetermined switching threshold to a value above the predetermined switching threshold, the economy level image is not switched until the environmental parameter value reaches the increasing threshold. Similarly, during the execution of follow-up driving control, if the value of an environmental parameter changes from a value above the predetermined switching threshold to a value below the predetermined switching threshold, the economy level image is not switched until the environmental parameter value reaches the decreasing threshold. Therefore, frequent switching of the economy level image can be suppressed.

[0014] The components of the present invention are not limited to the following ones. Figure 1 Other objects, other features, and advantages of the present invention can be easily understood from the description of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 FIG. 1 is a diagram showing a vehicle driving support device including a display control device according to an embodiment of the present invention. Figure 2 This is a diagram showing a situation where there is a vehicle traveling ahead. Figure 3 This is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. Figure 4 It is a graph showing evaluation values related to the air resistance reduction effect. Figure 5 It is a diagram showing a comprehensive evaluation image. Figure 6 It is a diagram showing a comprehensive evaluation image corresponding to the first evaluation (lowest evaluation), a comprehensive evaluation image corresponding to the second evaluation, a comprehensive evaluation image corresponding to the third evaluation, a comprehensive evaluation image corresponding to the fourth evaluation, and a comprehensive evaluation image corresponding to the fifth evaluation (highest evaluation). Figure 7 This is a diagram for explaining hysteresis processing. Figure 8 This is a diagram showing the change in the inter-vehicle distance after hysteresis processing has been performed. Figure 9 This is a graph showing evaluation values related to the air resistance reduction effect according to a modification of the embodiment of the present invention. DETAILED DESCRIPTION

[0016] Hereinafter, a display control device according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 FIG2 shows a vehicle driving assistance device 10 according to an embodiment of the present invention. The display control device according to the embodiment of the present invention is included in the vehicle driving assistance device 10. However, the vehicle driving assistance device 10 and the display control device may be configured separately, with some of the functions of the vehicle driving assistance device 10 described below (particularly the function of controlling the operation of the display device, which will be described later) being performed by the display control device, and the remaining functions being performed by the vehicle driving assistance device 10.

[0017] The vehicle driving assistance device 10 is mounted on the host vehicle 100. Hereinafter, the vehicle driving assistance device 10 will be described using as an example a case where the operator of the host vehicle 100 is a person who is riding in the host vehicle 100 and driving the host vehicle 100 (i.e., the driver of the host vehicle 100). However, the operator of the host vehicle 100 may also be a person who is not riding in the host vehicle 100 but is driving the host vehicle 100 remotely (i.e., a remote operator of the host vehicle 100).

[0018] Furthermore, the present invention can also be applied to vehicles that operate autonomously without the need for a driver or remote operator. Thus, when the vehicle 100 operates autonomously, the comprehensive evaluation results displayed on the display device, described later, are displayed to passengers in the vehicle 100 or to a remote observer who is monitoring the operation of the vehicle 100 via a remote control device.

[0019] like Figure 1 As shown, the vehicle driving assistance device 10 includes an ECU (electronic control unit) 90 as a control device. The ECU 90 includes a microcomputer as its main component. The microcomputer includes a CPU, storage media such as ROM, RAM, and non-volatile memory, as well as interfaces, etc. The CPU implements various functions by executing instructions, programs, or routines stored in the storage media. In particular, in this example, the vehicle driving assistance device 10 stores programs that implement the various controls executed by the vehicle driving assistance device 10 in the storage medium.

[0020] In this example, the vehicle driving assistance device 10 includes only one ECU 90. However, the vehicle driving assistance device 10 may also include multiple ECUs, with each ECU sharing the functions of the vehicle driving assistance device 10 described below. Furthermore, the vehicle driving assistance device 10 may also be configured so that the program stored in the storage medium can be updated (upgraded) via wireless communication (e.g., Internet communication) with an external device.

[0021] The vehicle 100 is equipped with a power unit 20 , a braking device 30 , a display device 40 , a peripheral information detection device 50 , and an auxiliary switch 60 .

[0022] The power unit 20 is a device that generates power to be applied to the host vehicle 100 (particularly, the drive wheels of the host vehicle 100), and in this example, includes an internal combustion engine 21 and an electric motor 22. The power unit 20 is electrically connected to the ECU 90. The vehicle driving assistance device 10 can control the power applied to the host vehicle 100 by controlling the operation of the internal combustion engine 21 and the electric motor 22.

[0023] The brake device 30 is a device that applies braking force to the host vehicle 100 (particularly, the wheels of the host vehicle 100), and in this example, includes a hydraulic brake device 31. The brake device 30 is electrically connected to the ECU 90. The vehicle driving assistance device 10 can control the braking force applied to the host vehicle 100 by controlling the operation of the hydraulic brake device 31.

[0024] The display device 40 is a device that displays various images to the driver of the vehicle 100, and in this example includes a display 41. The display device 40 is electrically connected to the ECU 90. The vehicle driving support device 10 can display various images on the display 41 via the display device 40.

[0025] The surrounding information detection device 50 detects information about the surroundings of the host vehicle 100. In this example, it includes an electromagnetic wave sensor 51 and an image sensor 52. The surrounding information detection device 50 is electrically connected to the ECU 90. The electromagnetic wave sensor 51 is, for example, a radar sensor such as a millimeter-wave radar. The vehicle driving assistance device 10 uses the electromagnetic wave sensor 51 to obtain information about objects around the host vehicle 100 as surrounding detection information IS. Furthermore, the image sensor 52 is, for example, a camera sensor. The vehicle driving assistance device 10 uses the image sensor 52 to obtain image information about the surroundings of the host vehicle 100 as surrounding detection information IS.

[0026] The auxiliary switch 60 is a device operated by the driver of the vehicle 100 to request execution of the economical following driving control described later, or to request suspension of the economical following driving control. The auxiliary switch 60 is electrically connected to the ECU 90. By operating the auxiliary switch 60, the driver can request the vehicle driving assistance device 10 to execute the economical following driving control, or to request suspension of the economical following driving control.

[0027] <Operation of vehicle driving assistance system> Next, the operation of the vehicle driving assistance device 10 will be described. The vehicle driving assistance device 10 is configured to execute the economical following driving control when execution of the control is requested. Furthermore, the vehicle driving assistance device 10 is configured to stop the economical following driving control when stopping the control is requested.

[0028] Economical following driving control is a type of automatic driving control, such as Figure 2 As shown, this is a type of following travel control in which the host vehicle 100 autonomously accelerates and decelerates to follow the preceding vehicle 200 when there is a preceding vehicle 200. In this example, the economical following travel control has an inertia travel mode and a power travel mode as control modes.

[0029] The inertia travel mode decelerates vehicle 100 by disconnecting power unit 20 from the drive wheels of vehicle 100, causing vehicle 100 to coast. The power travel mode accelerates vehicle 100. In particular, the power travel mode is an optimal power travel mode that operates power unit 20 at optimal energy efficiency, allowing vehicle 100 to travel under power.

[0030] If, while executing eco-following driving control in power driving mode, inter-vehicle distance D (the distance between preceding vehicle 200 and host vehicle 100) decreases and reaches the lower limit Dlower of the set inter-vehicle distance range Rdset, the control mode is switched from power driving mode to inertia driving mode. On the other hand, if, while eco-following driving control is in effect in inertia driving mode, inter-vehicle distance D increases and reaches the upper limit Dupper of the set inter-vehicle distance range Rdset, the control mode is switched from inertia driving mode to power driving mode.

[0031] The set inter-vehicle distance range Rdset is a range of inter-vehicle distances D with the set inter-vehicle distance Dset as the lower limit value Dlower and the distance longer than the set inter-vehicle distance Dset by a predetermined distance ΔD as the upper limit value Dupper. The set inter-vehicle distance Dset is pre-set by the driver of the host vehicle 100. Furthermore, the preceding vehicle 200 is another vehicle located within a predetermined distance D200 ahead of the host vehicle 100 and traveling in the host vehicle's driving lane (the lane in which the host vehicle 100 is currently traveling). The preceding vehicle 200 is detected based on the surrounding detection information IS. Furthermore, the inter-vehicle distance D is acquired based on the surrounding detection information IS.

[0032] In addition, the vehicle driving assistance device 10 is configured to execute the calculation at a predetermined calculation interval. Figure 3 The routine shown in FIG. 1 is used to perform a comprehensive evaluation of the degree of economy achieved by the economy-following driving control when predetermined conditions are met, and the results of this comprehensive evaluation are displayed on the display device 40. In other words, the vehicle driving assistance device 10 is configured to display a comprehensive evaluation image T (economy level image) representing the degree of economy, indicating the degree of low energy consumption associated with the driving of the host vehicle 100, on the display device 40 during the execution of the economy-following driving control. The economy level corresponds to an evaluation value E, described later. A larger evaluation value E indicates a higher degree of economy.

[0033] If it is at a predetermined timing, the vehicle driving assistance device 10 starts Figure 3 The process of the routine shown starts at step S300 , and the process proceeds to step S305 , where it is determined whether or not the economical following travel control is being executed.

[0034] If the determination in step S305 is "YES," the vehicle driving assistance device 10 proceeds to step S310 to acquire environmental parameters related to the driving environment of the host vehicle 100. In this example, the environmental parameters are the inter-vehicle distance D and the projected area A. The projected area A is the area of the preceding vehicle 200 when projected onto a vertical plane perpendicular to the front-rear horizontal line of the preceding vehicle 200 (a line extending horizontally in the longitudinal direction of the preceding vehicle 200). The projected area A is acquired based on the surrounding detection information IS.

[0035] Next, the vehicle driving assistance device 10 advances processing to step S315, where it obtains an evaluation value E (environmental evaluation value Ee) related to the air resistance reduction effect based on the inter-vehicle distance D and the projected area A. The air resistance reduction effect is the effect of reducing the air resistance experienced by the host vehicle 100 through the execution of the economical follow-up driving control. The air resistance reduction effect varies according to the inter-vehicle distance D and the projected area A. That is, when the host vehicle 100 is following the preceding vehicle 200, the shorter the inter-vehicle distance D, the smaller the air resistance experienced by the host vehicle 100. Furthermore, when the host vehicle 100 is following the preceding vehicle 200, the larger the projected area A of the preceding vehicle 200, the smaller the air resistance experienced by the host vehicle 100. Therefore, the environmental evaluation value Ee tends to increase as the inter-vehicle distance D decreases at the same projected area A. Furthermore, the environmental evaluation value Ee tends to increase as the projected area A increases at the same inter-vehicle distance D. Furthermore, the smaller the air resistance experienced by the vehicle 100 is, the less energy the vehicle 100 consumes, and the higher the economic efficiency is.

[0036] For example Figure 4 As shown, the environmental evaluation value Ee is set for each combination of the vehicle distance D and the projected area A.

[0037] exist Figure 4 In the diagram, reference numerals Rd1 to Rd4 each represent a range of inter-vehicle distance D. Inter-vehicle distance D within range Rd1 is shorter than inter-vehicle distance D within range Rd2. Furthermore, inter-vehicle distance D within range Rd2 is shorter than inter-vehicle distance D within range Rd3. Furthermore, inter-vehicle distance D within range Rd3 is shorter than inter-vehicle distance D within range Rd4. Furthermore, ranges Rd1 and Rd2, ranges Rd2 and Rd3, and ranges Rd3 and Rd4 are each continuous ranges.

[0038] In this example, when the inter-vehicle distance D is less than or equal to the upper limit DU of range Rd1, the inter-vehicle distance D is within range Rd1. Furthermore, when the inter-vehicle distance D is greater than the upper limit DU of range Rd1 (i.e., greater than or equal to the lower limit DL of range Rd2) and less than or equal to the upper limit DU of range Rd2, the inter-vehicle distance D is within range Rd2. Furthermore, when the inter-vehicle distance D is greater than the upper limit DU of range Rd2 (i.e., greater than or equal to the lower limit DL of range Rd3) and less than or equal to the upper limit DU of range Rd3, the inter-vehicle distance D is within range Rd2. Furthermore, when the inter-vehicle distance D is greater than the upper limit DU of range Rd3 (i.e., greater than or equal to the lower limit DL of range Rd4), the inter-vehicle distance D is within range Rd2.

[0039] In addition, Figure 4 In the figure, reference numerals Ra1 to Ra4 each represent a range of projected area A. The projected area A within range Ra1 is smaller than the projected area A within range Ra2. Furthermore, the projected area A within range Ra2 is smaller than the projected area A within range Ra3. Furthermore, the projected area A within range Ra3 is smaller than the projected area A within range Ra4. Furthermore, ranges Ra1 and Ra2, ranges Ra2 and Ra3, and ranges Ra3 and Ra4 are each continuous ranges.

[0040] In addition, in this example, when the projection area A is less than the upper limit value AU of the range Ra1, the projection area A is a value within the range Ra1. In addition, when the projection area A is greater than the upper limit value AU of the range Ra1 (that is, greater than the lower limit value AL of the range Ra2) and less than the upper limit value AU of the range Ra2, the projection area A is a value within the range Ra2. In addition, when the projection area A is greater than the upper limit value AU of the range Ra2 (that is, greater than the lower limit value AL of the range Ra3) and less than the upper limit value AU of the range Ra3, the projection area A is a value within the range Ra2. In addition, when the projection area A is greater than the upper limit value AU of the range Ra3 (that is, greater than the lower limit value AL of the range Ra4), the projection area A is a value within the range Ra2.

[0041] exist Figure 4 In the example shown, when projected area A is within a consistent range, the environmental evaluation value Ee tends to increase as the inter-vehicle distance D decreases. Furthermore, when inter-vehicle distance D is within a consistent range, the environmental evaluation value Ee tends to increase as the inter-vehicle distance A increases. For example, when inter-vehicle distance D is within the range Rd1 and projected area A is within the range Ra1, the environmental evaluation value Ee is "1." Thus, the environmental evaluation value Ee is set to a value that increases as the contribution to reducing energy consumption associated with driving the host vehicle 100 increases.

[0042] Next, the vehicle driving assistance device 10 proceeds to step S320 to obtain an evaluation value E related to the control mode (mode evaluation value Em). The mode evaluation value Em is set to a larger value when the economical following travel control is executed in the inertia travel mode than when the economical following travel control is executed in the power travel mode.

[0043] When the economical follow-up travel control is executed in the inertial travel mode, the energy consumption associated with the travel of the host vehicle 100 is very small. Therefore, in this example, the mode evaluation value Em when the economical follow-up travel control is executed in the inertial travel mode is set to "3".

[0044] Furthermore, while executing the economical follow-up driving control in the power drive mode, energy is consumed while the vehicle 100 is traveling. However, executing the economical follow-up driving control in the power drive mode is necessary to enable the subsequent execution of the economical follow-up driving control in the inertia drive mode. Executing the economical follow-up driving control in the power drive mode enables the subsequent execution of the economical follow-up driving control in the inertia drive mode. In other words, the economical follow-up driving control in the power drive mode contributes to reducing the energy consumption associated with the travel of the vehicle 100. Therefore, in this example, the mode evaluation value Em when executing the economical follow-up driving control in the power drive mode is set to "1."

[0045] As described above, the mode evaluation value Em is also set to a larger value as the degree of contribution to the reduction of energy consumption associated with the travel of the host vehicle 100 increases.

[0046] Next, the vehicle driving assistance device 10 advances the process to step S325 , and acquires a value obtained by summing the environment evaluation value Ee acquired in step S315 and the mode evaluation value Em acquired in step S320 as a total evaluation value Et.

[0047] Next, the vehicle driving assistance device 10 advances the processing to step S330, and determines a comprehensive evaluation (comprehensive evaluation) related to the degree of economy achieved by the economy-following driving control based on the total evaluation value Et. In this example, the comprehensive evaluation is a 4-level evaluation (i.e., the first evaluation, the second evaluation, the third evaluation, and the fourth evaluation) from the lowest comprehensive evaluation (lowest evaluation) to the highest comprehensive evaluation (highest evaluation). When the total evaluation value Et is "1", the comprehensive evaluation becomes the first evaluation (lowest evaluation). In addition, when the total evaluation value Et is "2", the comprehensive evaluation becomes the second evaluation. In addition, when the total evaluation value Et is "3", the comprehensive evaluation becomes the third evaluation. In addition, when the total evaluation value Et is "4" or above, the comprehensive evaluation becomes the fourth evaluation (highest evaluation).

[0048] Next, the vehicle driving assistance device 10 advances the processing to step S335, and displays an image representing the comprehensive evaluation (comprehensive evaluation image T) on the display device 40. Next, the vehicle driving assistance device 10 advances the processing to step S395, temporarily ending the processing of this routine. In this example, the comprehensive evaluation image T is Figure 5 The image shown.

[0049] Figure 5 The comprehensive evaluation image T shown includes a main image M and four sub-images S (i.e., a first sub-image S1, a second sub-image S2, a third sub-image S3, and a fourth sub-image S4). The main image M is an image simulating a leaf. The sub-images S are stick-shaped images, with the first sub-image S1, the second sub-image S2, the third sub-image S3, and the fourth sub-image S4 arranged in a row starting from the left.

[0050] like Figure 6 As shown, the comprehensive evaluation image T1 corresponding to the first evaluation is displayed with the main image M and the first sub-image S1 lit, and the second sub-image S2, the third sub-image S3, and the fourth sub-image S4 off. Furthermore, the comprehensive evaluation image T2 corresponding to the second evaluation is displayed with the main image M, the first sub-image S1, and the second sub-image S2 lit, and the third sub-image S3 and the fourth sub-image S4 off. Furthermore, the comprehensive evaluation image T3 corresponding to the third evaluation is displayed with the main image M, the first sub-image S1, the second sub-image S2, and the third sub-image S3 lit, and the fourth sub-image S4 off. Furthermore, the comprehensive evaluation image T4 corresponding to the fourth evaluation is displayed with the main image M, the first sub-image S1, the second sub-image S2, the third sub-image S3, and the fourth sub-image S4 all lit.

[0051] If the determination in step S305 is "No," the vehicle driving assistance device 10 advances the process to step S340, and if the display device 40 is currently displaying the comprehensive evaluation image T, the display is stopped. Next, the vehicle driving assistance device 10 advances the process to step S395, temporarily terminating the processing of this routine.

[0052] In this way, the vehicle driving assistance device 10 is configured to obtain the vehicle distance D and the projected area A (the values of environmental parameters that are parameters for specifying the degree of economy and that represent the driving environment of the vehicle 100) during the execution of the economy-following driving control, obtain the evaluation value E corresponding to the obtained vehicle distance D and the projected area A, obtain the total evaluation value Et (economy degree) based on the obtained evaluation value E, and display the comprehensive evaluation image T (economy degree image) representing the obtained total evaluation value Et through the display device 40.

[0053] As described above, since the comprehensive evaluation image T is displayed on the display device 40 , the driver of the host vehicle 100 can understand the degree of economy related to the driving of the host vehicle 100 by observing the comprehensive evaluation image T.

[0054] However, the vehicle driving assistance device 10 acquires the environmental evaluation value Ee in accordance with the inter-vehicle distance D and the projected area A. For example, if the projected area A is within the range Ra3, the inter-vehicle distance D repeatedly increases across the boundary between the ranges Rd1 and Rd2, causing the environmental evaluation value Ee to fluctuate between "3" and "2." This causes the comprehensive evaluation to fluctuate, and the comprehensive evaluation image T to fluctuate repeatedly, potentially causing the driver to become annoyed.

[0055] Therefore, the vehicle driving assistance device 10 is configured to use the inter-vehicle distance D obtained based on the surrounding detection information IS by applying hysteresis processing to the inter-vehicle distance D when the inter-vehicle distance D increases and exceeds the upper limit value DU of each range Rd1 to Rd3, and when the inter-vehicle distance D decreases and exceeds the lower limit value DL of each range Rd2 to Rd4 to obtain the environmental evaluation value Ee. Similarly, the vehicle driving assistance device 10 is configured to use the projected area A obtained based on the surrounding detection information IS by applying hysteresis processing to obtain the environmental evaluation value Ee when the projected area A increases and exceeds the upper limit value AU of each range Ra1 to Ra3, and when the projected area A decreases and exceeds the lower limit value AL of each range Ra2 to Ra4.

[0056] like Figure 7 As shown, hysteresis processing corrects the value input to the processing (input value Vi) and outputs this corrected value as the output value Vo. Specifically, when hysteresis processing begins when input value Vi increases and reaches third value V3 (time t70), output value Vo is maintained at third value V3 until input value Vi increases and reaches fourth value V4 (time t71). After input value Vi reaches fourth value V4, output value Vo begins to increase, and then increases as input value Vi increases. At this point, output value Vo is reduced by the difference between fourth value V4 and third value V3 (Vo = Vi - (V4 - V3)).

[0057] Then, when the input value Vi reaches the fifth value V5 and the output value Vo reaches the fourth value V4 (time t72), the input value Vi begins to decrease. From the time the input value Vi reaches the third value V3 (time t73), the output value Vo is maintained at the fourth value V4. Then, when the input value Vi reaches the third value V3, the output value Vo begins to decrease. Subsequently, as the input value Vi decreases, the output value Vo also decreases. At this point, the output value Vo is less than the input value Vi by the difference between the fourth value V4 and the third value V3 (Vo = Vi - (V4 - V3)).

[0058] Then, when the input value Vi reaches the first value V1 and the output value Vo reaches the second value V2 (time t74), the input value Vi begins to increase. The output value Vo is maintained at the second value V2 until the input value Vi reaches the third value V3 (time t75). After the input value Vi reaches the third value V3, the output value Vo begins to increase, and then increases in conjunction with the increase in the input value Vi. At this point, the output value Vo is less than the input value Vi by the difference between the fourth value V4 and the third value V3 (Vo = Vi - (V4 - V3)).

[0059] As described above, after the hysteresis process is started when the input value Vi increases and reaches the third value V3, the output value Vo is maintained at the third value V3 as long as the input value Vi fluctuates only between the fourth value V4 and the second value V2.

[0060] In addition, when the hysteresis processing of the input value Vi is started when the input value Vi decreases and reaches the third value V3, the input value Vi is corrected and the corrected value is output as the output value Vo through the hysteresis processing in such a way that the output value Vo is maintained at the third value V3 as long as the input value Vi changes only between the fourth value V4 and the second value V2.

[0061] Therefore, if Figure 8 As shown, when the input inter-vehicle distance Di varies, the output inter-vehicle distance Do is maintained at the upper limit DU of the range Rd1. The input inter-vehicle distance Di is the inter-vehicle distance D acquired by the vehicle driving assistance device 10 based on the surrounding detection information IS. The output inter-vehicle distance Do is the inter-vehicle distance D output through hysteresis processing.

[0062] Figure 8 The following example shows how the input vehicle distance Di changes when the projected area A is within the range Ra3. Figure 8 In the example shown, the input vehicle distance Di increases and reaches the upper limit value DU of the range Rd1 (time t80). Then, the input vehicle distance Di increases and starts to decrease before crossing the increasing vehicle distance Dth_U (time t81). The increasing vehicle distance Dth_U corresponds to Figure 7 The fourth value V4 of the example shown. Then, the input vehicle distance Di reaches the upper limit value DU of the range Rd1 (time t82), then decreases and starts to increase before crossing the decreasing vehicle distance Dth_L (time t83). In addition, the decreasing vehicle distance Dth_L corresponds to Figure 7 The second value V2 of the example shown. Then, the increase and decrease are repeated. Figure 8 In the example shown, when the input inter-vehicle distance Di increases and reaches the upper limit value DU of the range Rd1 (time t80 ), the hysteresis processing for the input inter-vehicle distance Di is started.

[0063] As described above, while the input inter-vehicle distance Di increases or decreases across the upper limit DU of the range Rd1, the output inter-vehicle distance Do is maintained at the upper limit DU of the range Rd1. Therefore, the environmental evaluation value Ee is maintained at the evaluation value E when the inter-vehicle distance D is within the range Rd1. In other words, the range between the increasing inter-vehicle distance Dth_U and the decreasing inter-vehicle distance Dth_L constitutes a dead zone for the input inter-vehicle distance Di.

[0064] That is, in this example, for example, the vehicle driving assistance device 10 is configured such that, during the execution of the economical following driving control, when the inter-vehicle distance D (value of the environmental parameter) changes from a value below the upper limit value DU of the range Rd1 (prescribed switching threshold) to a value greater than the upper limit value DU, before the inter-vehicle distance D reaches the increasing side inter-vehicle distance Dth_U (increasing side threshold), the inter-vehicle distance D is corrected to the upper limit value DU of the range Rd1, and a comprehensive evaluation image T (economical degree image) representing the total evaluation value Et (economical degree) obtained based on the evaluation value E corresponding to the corrected inter-vehicle distance D is displayed on the display device 40. During the execution of the economical following driving control, when the inter-vehicle distance D changes from a value greater than the upper limit value DU of the range Rd1 to a value less than the upper limit value DU, before the inter-vehicle distance D reaches the decreasing side inter-vehicle distance Dth_L (decreasing side threshold), the inter-vehicle distance D is corrected to a value greater than the upper limit value DU of the range Rd1, and a comprehensive evaluation image T representing the total evaluation value Et obtained based on the evaluation value E corresponding to the corrected inter-vehicle distance D is displayed on the display device 40.

[0065] Furthermore, the hysteresis processing may be configured such that, during the execution of the economy-following driving control, for example, when the inter-vehicle distance D changes from a value below the upper limit value DU of the range Rd1 to a value greater than the upper limit value DU, the inter-vehicle distance D is corrected to a value within the range Rd1 that is less than the upper limit value DU of the range Rd1 before the inter-vehicle distance D reaches the increasing inter-vehicle distance Dth_U. Similarly, the hysteresis processing may be configured such that, during the execution of the economy-following driving control, for example, when the inter-vehicle distance D changes from a value greater than the upper limit value DU of the range Rd1 to a value less than the upper limit value DU, the inter-vehicle distance D is corrected to a value greater than the upper limit value DU of the range Rd1 (the decreasing threshold value) before the inter-vehicle distance D reaches the decreasing inter-vehicle distance Dth_L of the range Rd1.

[0066] In this way, in this example, for example, the evaluation value E (first evaluation value) corresponding to the vehicle distance D (value of the environmental parameter) below the upper limit value DU (prescribed switching threshold) of the range Rd1 and the evaluation value E (second evaluation value) corresponding to the vehicle distance D greater than the upper limit value DU of the range Rd1 are different values. Furthermore, the vehicle driving assistance device 10 is configured such that, during the execution of the following driving control, when the vehicle distance D changes from a value below the upper limit value DU of the range Rd1 to a value greater than the upper limit value DU, before the vehicle distance D reaches the increasing side vehicle distance Dth_U (increasing side threshold) greater than the upper limit value DU of the range Rd1, a comprehensive evaluation image T (economic degree image) representing the degree of economy obtained based on the evaluation value E (first evaluation value) corresponding to the vehicle distance D below the upper limit value DU of the range Rd1 is displayed on the display device 40; and, during the execution of the following driving control, when the vehicle distance D changes from a value greater than the upper limit value DU of the range Rd1 to a value less than the upper limit value DU, before the vehicle distance D reaches the decreasing side vehicle distance Dth_L (decreasing side threshold) less than the upper limit value DU of the range Rd1, a comprehensive evaluation image T representing the degree of economy obtained based on the evaluation value E (second evaluation value) corresponding to the vehicle distance D greater than the upper limit value DU of the range Rd1 is displayed on the display device 40.

[0067] As described above, even if the inter-vehicle distance D frequently increases or decreases across the upper limit value DU of the range Rd1 during execution of the economy-following driving control, a total evaluation value Et is obtained based on the evaluation value E before the inter-vehicle distance D first crosses the upper limit value DU of the range Rd1, and a comprehensive evaluation image T showing the obtained total evaluation value Et is displayed. Consequently, frequent switching of the comprehensive evaluation image T can be suppressed.

[0068] In addition, the present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention.

[0069] Modifications For example Figure 9 As shown, the vehicle driving assistance device 10 can also be configured to obtain the environmental evaluation value Ee based on two mappings (increase direction mapping MapU and decrease direction mapping MapD) for obtaining the environmental evaluation value Ee using the vehicle distance D and the projected area A (values of environmental parameters) as independent variables, instead of obtaining the environmental evaluation value Ee based on the vehicle distance D and the projected area A to which hysteresis processing is implemented.

[0070] When the projected area A is within the range Ra3 and the inter-vehicle distance D increases, crossing the upper limit DU of the range Rd1 and falling within the range Rd2, the vehicle driving assistance device 10 obtains the environmental evaluation value Ee from both the increasing and decreasing directions maps MapU and MapD. In this case, the environmental evaluation value Ee obtained from the increasing direction map MapU is "3," and the environmental evaluation value Ee obtained from the decreasing direction map MapD is "2." The vehicle driving assistance device 10 adopts the environmental evaluation value Ee with the smaller difference from the environmental evaluation value Ee when the inter-vehicle distance D is within the range Rd1 as the environmental evaluation value Ee at this time. In this example, the environmental evaluation value Ee when the inter-vehicle distance D is within the range Rd1 is "3." Therefore, the vehicle driving assistance device 10 adopts the environmental evaluation value Ee ("3") obtained from the increasing direction map MapU as the environmental evaluation value Ee at this time.

[0071] On the other hand, when the projected area A is within the range Ra3, and the inter-vehicle distance D decreases, crossing the lower limit DL of the range Rd3 and falling within the range Rd2, the vehicle driving assistance device 10 obtains the environmental evaluation value Ee from both the increasing and decreasing directions maps MapU and MapD. In this case, the environmental evaluation value Ee obtained from the increasing direction map MapU is "3," and the environmental evaluation value Ee obtained from the decreasing direction map MapD is "2." As described above, the vehicle driving assistance device 10 adopts the environmental evaluation value Ee with the smaller difference from the environmental evaluation value Ee when the inter-vehicle distance D is within the range Rd3 as the environmental evaluation value Ee at this time. In this example, the environmental evaluation value Ee when the inter-vehicle distance D is within the range Rd3 is "2." Therefore, the vehicle driving assistance device 10 adopts the environmental evaluation value Ee ("2") obtained from the decreasing direction map MapD as the environmental evaluation value Ee at this time.

[0072] As described above, the increase direction map MapU is a map (first map) in which, when the projected area A is within the range Ra3, the evaluation value E corresponding to the inter-vehicle distance D (environmental parameter value) below the upper limit value DU (prescribed switching threshold) of the range Rd1 and the evaluation value E corresponding to the inter-vehicle distance D value greater than the upper limit value DU of the range Rd1 are set to the same level. Furthermore, the decrease direction map MapD is a map (first map) in which, when the projected area A is within the range Ra3, the evaluation value E corresponding to the inter-vehicle distance D (environmental parameter value) below the upper limit value DU (prescribed switching threshold) of the range Rd2 and the evaluation value E corresponding to the inter-vehicle distance D value greater than the upper limit value DU of the range Rd2 are set to the same level.

[0073] On the other hand, the increase direction map MapU is a map (second map) in which, when the projected area A is within the range Ra3, the evaluation value E corresponding to the inter-vehicle distance D (environmental parameter value) below the upper limit value DU (prescribed switching threshold) of the range Rd2 is set to a different degree than the evaluation value E corresponding to the inter-vehicle distance D value greater than the upper limit value DU of the range Rd2. Furthermore, the decrease direction map MapD is a map (second map) in which, when the projected area A is within the range Ra3, the evaluation value E corresponding to the inter-vehicle distance D (environmental parameter value) below the upper limit value DU (prescribed switching threshold) of the range Rd1 is set to a different degree than the evaluation value E corresponding to the inter-vehicle distance D value greater than the upper limit value DU of the range Rd1.

[0074] This also makes it possible to suppress frequent switching of the comprehensive evaluation image T. Description of the label

[0075] 10 ...Vehicle driving assistance device, 20 ...Power unit, 30 ...Braking device, 40 ...Display device, 50 ...Peripheral information detection device, 90 ...ECU, 100 ...Own vehicle, 200 ...Preceding vehicle

Claims

1. A display control device, The present invention includes a control device that displays an economy level image indicating the degree of economy on a display device during execution of a following travel control in which the host vehicle autonomously travels while allowing the distance between the host vehicle and a preceding vehicle to vary within a set inter-vehicle distance range, the economy level indicating the degree of low energy consumption associated with the travel of the host vehicle. The control device is configured to, during the execution of the following driving control, obtain a value of a parameter representing the driving environment of the host vehicle, i.e., an environmental parameter, which is a parameter defining the degree of economy, obtain an evaluation value corresponding to the obtained value of the environmental parameter, obtain the degree of economy based on the obtained evaluation value, and display the degree of economy image representing the obtained degree of economy on the display device. In the display control device, the first evaluation value corresponding to the value of the environmental parameter being equal to or less than a predetermined switching threshold and the second evaluation value corresponding to the value of the environmental parameter being greater than the predetermined switching threshold are different values; The control device is configured as follows: During execution of the following driving control, when the value of the environmental parameter changes from a value below the prescribed switching threshold to a value greater than the prescribed switching threshold, and before the value of the environmental parameter reaches an increasing threshold greater than the prescribed switching threshold, the economy image indicating the economy obtained based on the first evaluation value is displayed on the display device; During the execution of the follow-up driving control, when the value of the environmental parameter changes from a value greater than the prescribed switching threshold to a value less than the prescribed switching threshold, before the value of the environmental parameter reaches a decreasing side threshold less than the prescribed switching threshold, the economy degree image representing the economy degree obtained based on the second evaluation value is displayed by the display device.

2. The display control device according to claim 1, wherein: The control device is configured as follows: During execution of the following driving control, when the value of the environmental parameter exceeds the predetermined switching threshold from a value below the predetermined switching threshold to reach the increasing threshold, the economy image indicating the economy obtained based on the second evaluation value is displayed on the display device; During the execution of the follow-up driving control, when the value of the environmental parameter exceeds the prescribed switching threshold from a value greater than the prescribed switching threshold and reaches the reduction side threshold, the economy degree image representing the economy degree obtained based on the first evaluation value is displayed by the display device.

3. The display control device according to claim 1, wherein: The control device is configured as follows: During execution of the following driving control, when the value of the environmental parameter changes from a value below the prescribed switching threshold to a value above the prescribed switching threshold, before the value of the environmental parameter reaches the increasing threshold, the value of the environmental parameter is corrected to a value below the prescribed switching threshold, and the economy image representing the economy obtained based on the evaluation value corresponding to the corrected value of the environmental parameter is displayed on the display device. During the execution of the follow-up driving control, when the value of the environmental parameter changes from a value greater than the prescribed switching threshold to a value less than the prescribed switching threshold, before the value of the environmental parameter reaches the reduction side threshold, the value of the environmental parameter is corrected to a value greater than the prescribed switching threshold, and the economy degree image representing the economy degree obtained based on the evaluation value corresponding to the corrected environmental parameter value is displayed on the display device.

4. The display control device according to claim 1, wherein: The control device stores a first map and a second map for acquiring the evaluation value using the value of the environmental parameter as an independent variable. The first mapping is a mapping that sets the evaluation value corresponding to the value of the environmental parameter that is less than or equal to the predetermined switching threshold and the evaluation value corresponding to the value of the environmental parameter that is greater than the predetermined switching threshold to the same level. The second mapping is a mapping in which the evaluation value corresponding to the value of the environmental parameter that is equal to or less than the predetermined switching threshold and the evaluation value corresponding to the value of the environmental parameter that is greater than the predetermined switching threshold are set to different levels. The control device is configured as follows: During execution of the following driving control, when the value of the environmental parameter changes from a value below the prescribed switching threshold to a value greater than the prescribed switching threshold, and before the value of the environmental parameter reaches the increasing threshold, the economy image representing the economy is displayed on the display device, wherein the economy is obtained based on the evaluation value obtained from the first map using the value of the environmental parameter as an independent variable. During the execution of the follow-up driving control, when the value of the environmental parameter changes from a value greater than the prescribed switching threshold to a value less than the prescribed switching threshold, before the value of the environmental parameter reaches the reduction side threshold, the economy degree image representing the economy degree is displayed by the display device, wherein the economy degree is obtained based on the evaluation value obtained from the first mapping using the value of the environmental parameter as an independent variable.

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