Automatic vehicle height adjustment device for vehicle

Abstract

To make it less likely for a vehicle body to hit a snow step formed at a boundary between an area where a road heating device is installed and an area where it is not installed.SOLUTION: An automatic vehicle height adjustment device for a vehicle includes a vehicle height adjustment device for the vehicle and a control unit capable of controlling a height of a vehicle body from a road surface in response to a driver operation on the vehicle. The control unit determines the presence / absence of a snow-melting road surface or a snow step in a traveling direction of the vehicle in a state where the vehicle is traveling on a snow-covered road surface, and automatically switches a traveling mode of the vehicle from a normal traveling mode to a rough-road traveling mode. After automatically switching to the rough-road traveling mode, the control unit raises the vehicle body to a height equal to or higher than a predetermined height from the road surface and prohibits adjustment of the vehicle height by the driver operation.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an automatic vehicle height adjustment device for a vehicle. [Background technology]

[0002] Vehicles such as automobiles travel on roads. Patent Documents 1 and 2 disclose a vehicle height adjustment function. Using such technology, the vehicle can adjust its height above the road surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 04-365612 [Patent Document 2] Japanese Patent Application Publication No. 07-009830 [Patent Document 3] Japanese Patent Application Laid-Open No. 2000-159086 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in vehicles with a vehicle height adjustment function, it is common not only to automatically adjust the height as in Patent Documents 1 and 2, but also to allow the driver of the vehicle to adjust the height of the vehicle body from the road surface. As a result, even if the vehicle's automatic vehicle height adjustment device automatically adjusts the vehicle body height from the road surface, for example, the vehicle body height may become insufficient if the driver subsequently adjusts the vehicle height.

[0005] For example, as described in Patent Document 3, vehicles may travel through locations where road heating devices are installed. The road heating devices melt snow that has accumulated on the road surface using electric heating wires or hot water within the device. At locations or sections where the road heating devices are installed, the snow melts, exposing the road surface. Vehicles can travel safely on the exposed road surface without slipping. However, it is not practical to install road heating devices on all roads. Generally, road heating devices are installed only in limited areas, such as parking lots, major intersections and main roads, and on inclined road surfaces. Therefore, vehicles traveling in areas where road heating devices are installed to melt snow on the road surface will travel between sections where road heating devices are installed and sections where road heating devices are not installed. For example, when a vehicle tries to exit a parking lot onto a roadway via a sidewalk where a road heating device is installed, there is a possibility that the vehicle body will hit a step in the snow that has piled up high on the roadway. In particular, meltwater from melting snow caused by road heating systems seeps into the snow and freezes in the cold air at night, making the surface of snow steps hard and slippery. The drive wheels of vehicles slide on the snow steps at the boundary between sections with and without heating systems, making it difficult for them to traverse the snow steps. For example, high snow steps of about 20 centimeters are difficult for vehicles to overcome. In this case, if the height of the vehicle body from the road surface is raised as in Patent Documents 1 and 2, the vehicle body will be less likely to hit the snow step at the boundary between the location where the road heating device is installed and the location where it is not installed. However, if the vehicle's height adjustment device automatically adjusts the height of the vehicle body from the road surface and then the driver manually adjusts the height of the vehicle body, the height of the vehicle body from the road surface will be insufficient, increasing the possibility that the vehicle body will hit a snowy bump.

[0006] In this way, it is necessary for a vehicle to make it difficult for the vehicle body to hit snow bumps at the boundary between areas where road heating devices are installed and areas where they are not installed. [Means for solving the problem]

[0007] An automatic vehicle height adjustment device according to one embodiment of the present invention includes a vehicle height adjustment device for adjusting the height of a vehicle body from a road surface, a control unit that can control the height of the vehicle body from a road surface by the vehicle height adjustment device through operation by a driver of the vehicle, a position acquisition device that acquires the position of the vehicle, a regional information providing device that provides information on snow melting regions including installation locations or installation sections where snow melting devices for melting snow on the road surface are installed, and a snow accumulation information providing device that provides information on snow accumulation on a road surface in the traveling direction of the vehicle, and the control unit Based on the information acquired by the snow accumulation information providing device, it determines whether there is a snow-melted road surface in the direction of travel of the vehicle, or whether there is a snow step between the snow-melted road surface and the snow-covered road surface, and if there is a snow-melted road surface or a snow step in the direction of travel of the vehicle, it automatically switches the vehicle's driving mode from a normal driving mode to a rough road driving mode, and after automatically switching to the rough road driving mode, it uses the vehicle height adjustment device to raise the vehicle body to a predetermined height or more from the road surface while the vehicle is traveling on the snow-covered road surface, and prohibits the driver from adjusting the vehicle height while the vehicle is traveling after automatically switching to the rough road driving mode. [Effects of the Invention]

[0008] In the present invention, the control unit of the vehicle's automatic vehicle height adjustment device determines whether there is a snow-melted road surface in the vehicle's direction of travel, or whether there is a snow step between the snow-melted road surface and the snow-covered road surface, when the vehicle is traveling on a snow-covered road surface in a snow-melting area that includes an installation location or installation section where a snow-melting device for melting snow on the road surface is installed. When there is melting snow in the direction of travel or when there is a snow bump in the direction of travel, the control unit executes control to automatically raise the height of the vehicle body above the road surface. In this case, the control unit does not simply raise the height of the vehicle body above the road surface, but automatically switches the vehicle's driving mode from normal driving mode to rough road driving mode. After automatically switching to rough road driving mode, the control unit uses the vehicle height adjustment device to raise the vehicle body above a predetermined height above the road surface while the vehicle is traveling on a snow-covered road. Furthermore, when the control unit is in the automatically switched rough road driving mode, it prohibits the driver from adjusting the vehicle height. As a result, when the vehicle is traveling in a snow-melting area that includes a location or section where a snow-melting device is installed, the vehicle height adjustment device of the present invention can maintain the automatically switched height without the driver having to adjust the height again after automatically raising the vehicle body above a predetermined height from the road surface. After the height has been automatically adjusted, the vehicle can be expected to travel over high snow steps at the boundary between locations where a snow-melting device is installed and locations where it is not installed, without the vehicle body hitting the snow steps. The vehicle runs while maintaining a height from the road surface that is automatically adjusted by the vehicle height adjustment device, so even when running in a snowmelt area that includes snow steps formed on the road surface due to the installation location or installation section of a snow melting device, the vehicle can run while maintaining a height that is less likely to hit the snow steps. Moreover, because the height of the vehicle body from the road surface is automatically adjusted and maintained high, the driver does not need to manually adjust the height of the vehicle body every time the road surface alternates between melted snow and snow-covered snow, or every time a snow step occurs.The driver can concentrate on driving without being busy adjusting the height of the vehicle body from the road surface, and can travel in snowmelt regions where the road surface alternates between melted snow and snow-covered snow, or where snow steps occur repeatedly. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram of a state in which an automobile according to an embodiment of the present invention is traveling from a parking lot onto a snowy roadway. [Figure 2] FIG. 2 is an explanatory diagram of the main configuration of a control system that functions as an automatic vehicle height adjustment device for the automobile shown in FIG. [Figure 3] FIG. 3 is a flowchart of the manual vehicle height adjustment control that is repeatedly executed by the control unit in FIG. [Figure 4] FIG. 4 is a flowchart of the start control of the automatic rough road driving mode including the vehicle height adjustment repeatedly executed by the control unit in FIG. [Figure 5] FIG. 5 is a flowchart of the automatic rough road driving mode control repeatedly executed by the control unit in FIG. [Figure 6] FIG. 6 is a flowchart of the control for canceling the automatic rough road traveling mode, which is repeatedly executed by the control unit in FIG. [Figure 7] FIG. 7 is an explanatory diagram of an example of driving of the automobile of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] FIG. 1 is an explanatory diagram of a state in which an automobile 1 according to an embodiment of the present invention is traveling from a garage 101 in a parking lot onto a roadway 103 covered with snow. An automobile 1 in Fig. 1 is an example of a vehicle. The automobile 1 has a body 2. The body 2 is supported by front and rear wheels and is spaced above the road surface.

[0012] 1, an automobile 1 is parked in a covered garage 101. In front of the garage 101, there are a sidewalk 102 and a roadway 103. The sidewalk 102 and the roadway 103 form a road. In this case, the automobile 1 starts traveling from a parking garage 101, passes a sidewalk 102, and proceeds onto a roadway 103. After that, the automobile 1 travels along the roadway 103 and arrives at the destination.

[0013] In areas with heavy snowfall in winter, snow accumulates on the road surface. When snow accumulates on the sidewalk 102 or roadway 103, it affects the movement of people and the running of vehicles. For this reason, in regions where snow accumulates in winter, snow melting devices such as road heating devices 104 for melting snow on the road surface may be installed under the road surface of the sidewalk 102 or roadway 103. In Fig. 1, the road heating device 104 is installed under the road surface of the sidewalk 102. In this case, the road heating device 104 can melt the snow on the road surface of the sidewalk 102 entirely by using an electric heating wire or hot water inside the device. In this way, in the installation location or section where the road heating device 104 is installed, the snow on the road melts entirely, exposing the road surface. With the road surface exposed, the automobile 1 can travel safely without slipping on the road surface.

[0014] However, it is not realistic to install road heating devices 104 on all road surfaces, so road heating devices 104 are generally installed in limited locations, such as parking lots, major intersections and main roads, and sloping roads. Therefore, an automobile 1 traveling in an area where such a road heating device 104 is installed will travel through sections where the road heating device 104 is installed and sections where the road heating device 104 is not installed. When starting to travel from a garage 101 as shown in FIG. 1, the automobile 1 must pass through a sidewalk 102 where the road heating device 104 is installed, exit onto a roadway 103 where the road heating device 104 is not installed, and travel along the roadway 103. Furthermore, around the installation location or installation section of the road heating device 104, there are sections where the road heating device 104 is not installed. The difference in height between the installation location or installation section of the road heating device 104 and the surrounding snow accumulation can be about 20 centimeters. As a result, as shown by the dashed line in Figure 1, the body 2 of the automobile 1 hits a snowy step caused by high snow accumulation 105 on the roadway 103. If the body 2 hits the frozen snow step hard, the bumper and bottom of the body 2 may be damaged or broken. Furthermore, if snow or water gets into the engine compartment of the automobile 1, it may cause the engine to malfunction.

[0015] Furthermore, the meltwater from the road heating device 104 seeps into the surrounding snow and freezes due to the cold air at night. As a result, the snow bumps around the road surface where the road heating device 104 is installed harden and become slippery due to being worn down by spinning wheels. For example, if the height of the snow step is about 20 centimeters, even a car 1 equipped with a brake LSD (limited slip differential) may find that the drive wheels slip on the frozen snow step and the car cannot easily pass over the snow step. The driver must overcome the snowy steps by, for example, driving the car 1 at an angle to the snowy steps.

[0016] FIG. 2 is an explanatory diagram of the main configuration of a control system 10 of the automobile 1 that functions as an automatic vehicle height adjustment device for the automobile 1 of FIG. 2 includes a vehicle communication device 11, a GNSS receiver 12, high-precision map data 13, an exterior camera 14, a radar device 15, a road surface temperature sensor 16, a near-infrared sensor 17, a rain sensor 18, an outside air temperature sensor 19, a wheel speed sensor 20, and a control unit 24 to which these are connected. The control unit 24 is also connected to a vehicle height adjustment button 21, a driving mode button 22, a vehicle height adjustment device 25, and a vehicle dynamics control (VDC) device 26. As shown in the lower part of FIG. 2, the automobile 1 of FIG. 1 has a plurality of suspension devices 31 provided between each of the plurality of wheels or axles and the vehicle body 2, and drivetrain members 40 that drive the drive wheels of the automobile 1. The drivetrain members 40 include, for example, an engine 45, a transmission 46, and drive transmission members. The automobile 1 of FIG. 1 is a four-wheel drive vehicle, and all of the front, rear, left, and right wheels function as drive wheels. A front limited slip differential (LSD) 48 is provided between the left front drive wheel 41 and the right front drive wheel 42. A rear limited slip differential 49 is provided between the left rear drive wheel 43 and the right rear drive wheel 44.

[0017] The GNSS receiver 12 receives radio waves from a plurality of GNSS (Global Navigation Satellite System) satellites, and generates and acquires the current position and current time of the automobile 1, which is the automobile itself. The GNSS receiver 12 functions in the automobile 1 as a position acquisition device that acquires the position of the automobile 1 .

[0018] The high precision map data 13 includes information about roads on which the automobile 1 travels. The high precision map data 13 includes node information and link information as information about each road. The high precision map data 13 may further include information about the installation locations and installation sections of the road heating devices 104 as information about each road. The information about the installation locations and installation sections of the road heating devices 104 may be included as attribute information of the link information for each lane of the sidewalk 102 or the roadway 103. The high precision map data 13 may also include information for distinguishing between snow-melting regions that include installation locations or installation sections where the road heating devices 104 are installed and non-snow-melting regions where the road heating devices 104 are not installed. Such regional information may be information for each administrative district, such as a prefecture, city, town, or village. The high-precision map data 13 functions as a local information providing device that provides the automobile 1 with information on snow-melting areas including the locations or sections where road heating devices 104 for melting snow on the road surface are installed.

[0019] Exterior camera 14 captures images of the surroundings of automobile 1. Exterior camera 14 may be, for example, a stereo camera, a monocular camera, or a 360-degree camera. In automobile 1 of FIG. 1, exterior camera 14 is installed in the passenger compartment facing forward, which is the direction of travel of automobile 1. Such exterior camera 14 can capture images of the snow condition on the road surface in the direction of travel of automobile 1. Furthermore, exterior camera 14 may calculate the distance and direction from the vehicle to a cross section of snow based on the parallax of the stereo camera, the image coordinates in the captured image, etc.

[0020] The radar device 15 and the near-infrared sensor 17 output scanning waves such as laser light to the surroundings of the automobile 1 and receive reflected light of the scanning waves to generate spatial information about the surroundings of the automobile 1. Information about the state of snow accumulation around the automobile 1 can be generated. The vehicle exterior camera 14, radar device 15, or near-infrared sensor 17 functions as a snow accumulation information providing device for providing information about snow accumulation on the road surface in the direction of travel of the vehicle 1.

[0021] The road surface temperature sensor 16 detects the temperature of the road surface below the automobile 1 . The rain sensor 18 detects rain falling on the automobile 1 . The outside air temperature sensor 19 detects the outside air temperature around the automobile 1 . The information from these sensors can be used to estimate the hardness of snow that has accumulated on the road on which the automobile 1 is traveling.

[0022] The wheel speed sensors 20 detect the rotation speed of the wheels of the automobile 1. In the case of a four-wheel drive vehicle such as the automobile 1 of this embodiment, it is desirable to provide the wheel speed sensors 20 on all four drive wheels.

[0023] The vehicle communication device 11 communicates with, for example, a server device (not shown) and acquires information used by the control system 10 of the automobile 1 for control from the server device. The vehicle communication device 11 may acquire information from a server device that can be used in the same way as the information acquired by the above-mentioned devices and sensors. In this case, the vehicle communication device 11 may function as a location acquisition device, a local information providing device, or a snow accumulation information providing device. The vehicle communication device 11 may acquire information such as the location of the vehicle, weather, and snowfall map from the server device.

[0024] The driving mode button 22 is a button for switching the driving mode of the automobile 1 by operation by the driver. The driving modes of the automobile 1 include a normal driving mode suitable for driving on paved roads, a rough road driving mode suitable for driving on rough roads with bumps, etc., and the like. When driving on a rough road, the driver can operate the driving mode button 22 at his / her own discretion and select the rough road driving mode as a driving mode suitable for the condition of the road on which the automobile 1 is driving, and set it for the automobile 1.

[0025] The VDC device 26 performs control to suppress unstable behavior of the vehicle 1 by individually controlling the brakes and engine output of each drive wheel of the vehicle 1. For example, the VDC device 26 uses traction control to suppress spin of the drive wheels that occurs on slippery roads. For example, the VDC device 26 uses skid control to suppress wheel skid during sudden steering or cornering on slippery roads. For this reason, the VDC device 26 operates as a brake LSD that individually controls the brakes of each drive wheel, and induces a predetermined operation in the front LSD 48 and the rear LSD 49. For example, if left front drive wheel 41 spins, VDC device 26 applies a weak brake to left front drive wheel 41 to prevent spinning of left front drive wheel 41. The driving force of engine 45 is transmitted to right front drive wheel 42, which will stop if left front drive wheel 41 spins, via front LSD 48. Both left front drive wheel 41 and right front drive wheel 42 can be rotated and driven by the driving force of engine 45 under conditions in which left front drive wheel 41 spins, due to control of the brake LSD. Furthermore, if the right front drive wheel 42 spins, the VDC device 26 applies a weak brake to the right front drive wheel 42 to prevent the right front drive wheel 42 from spinning. The driving force of the engine 45 is transmitted to the left front drive wheel 41, which stops when the right front drive wheel 42 spins, via the front LSD 48. Both the left front drive wheel 41 and the right front drive wheel 42 can be rotated and driven by the driving force of the engine 45 under conditions in which the right front drive wheel 42 spins due to the control of the brake LSD. By controlling the brake LSD in this manner, VDC device 26 can transmit the driving force of engine 45 to both the left and right drive wheels even in a situation where one of the left and right drive wheels starts to spin. Even on a slippery road surface where one of the left and right drive wheels starts to spin, vehicle 1 can travel in a way that allows it to escape the slippery road surface by driving both the left and right drive wheels. VDC device 26 can determine that one of the drive wheels is starting to spin based on the difference in rotational speed between the left and right drive wheels measured by wheel speed sensor 20, and then control the brake LSD. The performance of the brake LSD provided by the VDC device 26 is basically optimized to the extent that it can suppress spin of one of the drive wheels on flat roads such as paved roads on which the automobile 1 normally travels. Note that the braking provided by the brake LSD control is not strong enough to stop the automobile 1.

[0026] The vehicle height adjusting device 25 executes control to adjust the height of the body 2 of the automobile 1 from the road surface. When the driver operates the vehicle height adjustment button 21 , the vehicle height adjustment device 25 changes the length of the plurality of suspension devices 31 of the automobile 1 under the control of the control unit 24 to adjust the vehicle height of the automobile 1 . The vehicle height of the automobile 1 can be adjusted within a range from a minimum height (MIN) to a maximum height (MAX) by changing the lengths of the plurality of suspension devices 31, as shown in the drawing. The driver can adjust the vehicle height according to their preference, ranging from minimum height (MIN) to maximum height (MAX).

[0027] The control unit 24 controls the running of the automobile 1 based on inputs from the various devices and sensors connected to the control unit 24, as described above. For example, the control unit 24 controls the height of the vehicle body 2 from the road surface by the vehicle height adjustment device 25 in response to the operation of the vehicle height adjustment button 21 by the driver of the automobile 1 .

[0028] Furthermore, when the vehicle 1 is traveling on a road with snow accumulation or snow bumps, the control unit 24 automatically switches the driving mode of the vehicle 1 from the normal driving mode to the rough road driving mode while the vehicle 1 is traveling. Hereinafter, the rough road driving mode that the control unit 24 automatically switches to without the driver operating the driving mode button 22 is referred to as the automatic rough road driving mode. The automatic rough road driving mode is a mode that is based on the setting of the rough road driving mode, but performs switching control that is not available in the rough road driving mode.

[0029] Then, while traveling in the automatic rough road traveling mode, the control unit 24 uses the vehicle height adjustment device 25 to automatically control the height of the vehicle body 2 from the road surface to a maximum height (MAX) and maintains that height. As a result, the vehicle body 2 of the automobile 1 is raised to a predetermined height or higher from the road surface. Note that the height of the vehicle body 2 while traveling in the automatic rough road traveling mode may be any height that does not cause the vehicle body 2 to hit snow bumps hard when going over them. Therefore, the height of the vehicle body 2 does not necessarily have to be raised to the maximum height (MAX) of the height adjustment range. Furthermore, while the vehicle is traveling in the automatic rough road traveling mode, the control unit 24 switches the performance of the brake LSD by the VDC device 26 between a first slip suppression brake mode and a second slip suppression brake mode. Here, the performance of the brake LSD in the first spin suppression braking mode may be the same as the performance of the brake LSD in normal operation described above. In other words, the performance of the brake LSD in the first spin suppression braking mode may be such that, when either the left or right drive wheel spins while the automobile 1 is traveling on a paved road, the brake LSD applies a brake to the spinning drive wheel to a degree that suppresses spin. Furthermore, the performance of the brake LSD in the second spin suppression braking mode is strengthened compared to the first spin suppression braking mode. That is, the performance of the brake LSD in the second spin suppression braking mode may be such that the brake is strengthened to effectively suppress spin of the drive wheels when passing over large slippery snow bumps. Here, the VDC device 26 may obtain enhanced brake LSD performance in the second spin suppression braking mode by increasing the brake pressure increase speed for suppressing spinning of the spinning drive wheels compared to the first spin suppression braking mode. In addition, the VDC device 26 may obtain enhanced brake LSD performance in the second spin suppression braking mode by delaying the brake pressure reduction timing for suppressing spinning of the spinning drive wheels compared to the first spin suppression braking mode. This enhances the performance of the brake LSD, and more effectively suppresses spin of the drive wheels when going over large snow bumps. As a result, spinning of the left and right drive wheels is suppressed when going over large, slippery snow bumps. The driving force of the engine 45 is transmitted to the left and right drive wheels via the LSD. With spinning of both the left and right drive wheels suppressed, the left and right drive wheels are both driven by the driving force of the engine 45, enabling the vehicle to go over large, slippery snow bumps more powerfully. The VDC device 26 may also enhance the performance of the brake LSD by changing only one of the brake pressure increase speed and the brake pressure reduction timing.

[0030] FIG. 3 is a flowchart of the manual vehicle height adjustment control that is repeatedly executed by the control unit 24 of FIG. When the driver is in the automobile 1, the control unit 24 repeatedly executes the manual vehicle height adjustment control of FIG.

[0031] In step ST1, the control unit 24 determines whether or not the vehicle height has been manually adjusted. If the driver has not operated the vehicle height adjustment button 21, the control unit 24 determines that the vehicle height has not been manually adjusted, and repeats this process. Then, when the driver operates the vehicle height adjustment button 21, the control unit 24 determines that the vehicle height has been manually adjusted, and advances the process to step ST2.

[0032] In step ST2, the control unit 24 determines whether the current driving mode of the vehicle is the automatic rough road driving mode. If the current driving mode of the vehicle is, for example, a normal driving mode or a manual rough road driving mode, the control unit 24 determines that the mode is not the automatic rough road driving mode, and ends this control. On the other hand, if the current driving mode of the vehicle has been switched to the automatic rough road driving mode by the control unit 24 without the driver's operation, the control unit 24 determines that the mode is the automatic rough road driving mode and proceeds to step ST3.

[0033] In step ST3, the control unit 24 instructs the vehicle height adjusting device 25 to adjust the vehicle height to a height corresponding to the operation. Under the control of the control unit 24, the vehicle height adjusting device 25 changes the lengths of the plurality of suspension devices 31 of the automobile 1, and adjusts the vehicle height of the automobile 1 to a height corresponding to the operation. The vehicle height of the automobile 1 is adjustable within a range from a minimum height (MIN) to a maximum height (MAX), as shown in Fig. 3. The driver can adjust the vehicle height within the range from the minimum height (MIN) to the maximum height (MAX) according to his or her preference.

[0034] In step ST4, the control unit 24 records the height of the vehicle body 2 after the manual adjustment in the memory 27. The height of the vehicle body 2 that was last manually adjusted by the driver is recorded in the memory 27 as the last memory. Thereafter, the control unit 24 ends this control.

[0035] FIG. 4 is a flowchart of the start control of the automatic rough road driving mode, which includes the automatic vehicle height adjustment process of the automobile 1, which is repeatedly executed by the control unit 24 of FIG. The control unit 24 repeatedly executes the control for starting the automatic rough road driving mode shown in FIG. 4 while the automobile 1 is traveling. The control unit 24 can set the driving mode of the automobile 1 to the automatic rough road driving mode by controlling the start of the automatic rough road driving mode shown in FIG.

[0036] In step ST11, the control unit 24 determines whether the area in which the vehicle is currently traveling is a snow-melting area in which the road heating device 104 is installed. The control unit 24 may determine whether the area in which the vehicle is currently traveling is a snow-melting area, for example, based on the current position of the vehicle obtained by the GNSS receiver 12 and the area information in the high-precision map data 13. Alternatively, for example, the control unit 24 may determine whether the vehicle is in a snow-melting region by using information acquired by communicating with a server device (not shown) using the vehicle communication device 11. The control unit 24 may also acquire a region determination result from a server device (not shown) via the vehicle communication device 11, and determine whether the vehicle is in a snow-melting region based on the determination result. If the area in which the vehicle is currently traveling is a non-snow-melting area, but not a snow-melting area, the control unit 24 repeats this process. If the area in which the vehicle is currently traveling is a snow-melting area, the control unit 24 advances the process to step ST12. In addition, the control unit 24 may not simply make a judgment based on the area setting in the high-precision map data 13, but may also obtain information such as the current snow accumulation state, the current season, and the current weather from the server device and use this information in combination to make a judgment as to whether the area in which the vehicle is currently traveling is actually a snow-melting area.

[0037] In step ST12, the control unit 24 determines whether the vehicle is currently traveling on a snow-covered road surface based on the image captured by the exterior camera 14 and the spatial information around the vehicle 1 obtained by the radar device 15 or the near-infrared sensor 17. Here, a snow-covered road surface may be a road surface in which snow has accumulated over almost the entire surface of the roadway 103. A road surface in which the snow has melted over almost the entire surface by the road heating device 104 and the road surface itself is exposed is not included in the snow-covered road surface. When the road surface or lane surface at the end of the roadway 103 on which the host vehicle is traveling is substantially entirely white, the control unit 24 may determine that the host vehicle is traveling on a snow-covered road surface. If the vehicle is traveling on a snow-covered road surface, the control unit 24 advances the process to step ST13. If the vehicle is not traveling on a snow-covered road, the control unit 24 returns the process to step ST11. In addition, the control unit 24 may make an equivalent determination using other information that can be used to determine whether the vehicle is traveling on a snow-covered road, such as weather information, detection information from the rain sensor 18, outside air temperature, road surface temperature, snow map information from a weather server device, etc.

[0038] In step ST13, the control unit 24 determines whether there is a snow-melting road surface in the traveling direction of the automobile 1, or whether there is a snow step between the snow-melting road surface and the snow-covered road surface. The control unit 24 determines whether there is a snow-melting road surface or snow steps in the direction of travel of the vehicle based on the image captured by the exterior camera 14 and spatial information around the vehicle 1 obtained from the radar device 15 or near-infrared sensor 17. If there is either a snow-melting road surface or a snow-bump in the traveling direction of the vehicle, the control unit 24 advances the process to step ST14. If there is neither a snow-melted road surface nor a snow step in the traveling direction of the vehicle, the control unit 24 returns the process to step ST11. In this way, when the vehicle is traveling on a snow-covered road surface in a snow-melting region and there is either a snow-melting road surface or a snow step in the traveling direction of the vehicle, the control unit 24 advances the process to step ST14.

[0039] From step ST14, the control unit 24 detects that there is an installed section in the direction of travel of the vehicle where the road heating device 104 is installed to create a snow-melting road surface, and that there is a possibility that there is a snow step beyond the installed section at the boundary between the installed section and the non-installed section, so it starts control to respond to this. The control unit 24 switches the vehicle height of the automobile 1 and the performance of the brake LSD in conjunction with the change in driving mode. First, the control unit 24 switches the driving mode of the automobile 1 from the normal driving mode to the automatic rough road driving mode. The control unit 24 automatically switches the driving mode to the automatic rough road driving mode regardless of the driver's operation of the driving mode. As a result, the driving mode of the automobile 1 is set to the automatic rough road driving mode regardless of the driver's operation of the driving mode. The control unit 24 may light up the driving mode button 22 in the color of the rough road driving mode. When the automatic rough road driving mode is set, the control unit 24 determines in step ST2 of Fig. 3 that the driving mode of the vehicle is the automatic rough road driving mode. As a result, in the manual vehicle height adjustment control of Fig. 3, the control unit 24 does not issue a vehicle height adjustment instruction in step ST3. Manual vehicle height adjustment by the driver is prohibited.

[0040] In step ST15, the control unit 24 changes the performance of the brake LSD by the VDC device 26 from the first slip suppression brake mode to the second slip suppression brake mode while the vehicle is traveling on a snow-covered road surface.

[0041] In step ST16, the control unit 24 instructs the vehicle height adjusting device 25 to raise the vehicle height of the automobile 1 to the maximum height (MAX) while the automobile 1 is traveling on a snowy road surface. The vehicle height adjusting device 25 raises the vehicle height of the automobile 1 to the maximum height (MAX) while the automobile 1 is traveling on a snowy road surface. Thereafter, the control unit 24 ends this control.

[0042] As a result, the vehicle height of the automobile 1 is raised to the maximum height (MAX) while traveling on a snow-covered road surface. As a result, the body 2 of the automobile 1 is raised to a predetermined height or higher from the road surface. Furthermore, even if the driver subsequently attempts to manually adjust the vehicle height, the adjustment will no longer be made. The vehicle height of the automobile 1 is maintained at the maximum height (MAX). Furthermore, with the vehicle height maintained at its maximum height, the vehicle 1, with the brake LSD performance enhanced, travels from a snow-covered road surface onto a snow-melting road surface in a section where the road heating device 104 is installed. The vehicle 1 can also travel over a snow step at the boundary between the section where the road heating device 104 is installed and the road surface where it is not installed. Because the brake LSD performance is enhanced when traveling over this snow step, the vehicle 1 can smoothly travel over the snow step with driving force acting on both the left and right drive wheels without causing one of the drive wheels to spin. Even if the snow step is about 20 centimeters high, the vehicle 1 with the enhanced brake LSD can smoothly pass over the snow step without the drive wheels continuing to slip on the high snow step at the boundary between the section where the road heating device 104 is installed and the section where it is not installed.

[0043] FIG. 5 is a flowchart of the automatic rough road traveling mode control that is repeatedly executed by the control unit 24 of FIG. The control unit 24 repeatedly executes the automatic rough road driving mode control of FIG. 5 while the automobile 1 is traveling. The control unit 24 allows the vehicle height to be adjusted by the driver during the automatic rough road driving mode control of FIG.

[0044] In step ST21, the control unit 24 determines whether the current driving mode is the automatic rough road driving mode. If the current driving mode is other than the automatic rough road driving mode, the control unit 24 repeats this process. If the current driving mode is the automatic rough road driving mode, the control unit 24 advances the process to step ST22.

[0045] In step ST22, the control unit 24 determines whether the current vehicle speed of the traveling automobile 1 after automatically switching to the rough road automatic traveling mode is equal to or greater than the first speed threshold. Here, the first speed threshold may be a threshold value higher than the speed range expected when traveling on a rough road such as a road section with snow bumps, and may be, for example, 40 km / h. If the current vehicle speed of the automobile 1 is not equal to or greater than the first speed threshold, the control unit 24 advances the process to step ST27. If the current vehicle speed of the automobile 1 is equal to or greater than the first speed threshold, the control unit 24 advances the process to step ST23.

[0046] In step ST23, the control unit 24 changes the performance of the brake LSD from the second slip suppression brake mode to the first slip suppression brake mode. When the vehicle speed of the traveling automobile 1 after automatically switching to the automatic rough road driving mode becomes equal to or greater than a first speed threshold, the control unit 24 changes the performance of the brake LSD to a first slip suppression brake mode without returning the height of the vehicle body 2 from the road surface using the vehicle height adjustment device 25. Furthermore, the control unit 24 internally maintains the setting of the automatic rough road traveling mode.

[0047] From step ST24, the control unit 24 accepts manual vehicle height adjustment of the automobile 1 while the automobile 1 is traveling in the automatic rough road traveling mode. The control unit 24 accepts manual vehicle height adjustment of the automobile 1 only when the automobile 1 is traveling at a speed that would not be reached when traveling on a road section with snow bumps or the like. First, the control unit 24 determines whether or not the vehicle height has been manually adjusted. If the driver has not operated the vehicle height adjustment button 21, the control unit 24 determines that the vehicle height has not been manually adjusted, and advances the process to step ST27. If the driver is operating the vehicle height adjustment button 21, the control unit 24 determines that the vehicle height is being manually adjusted, and advances the process to step ST25.

[0048] In step ST25, the control unit 24 executes manual vehicle height adjustment control. The control unit 24 instructs the vehicle height adjustment device 25 to adjust the vehicle height to a height corresponding to the operation. Under the control of the control unit 24, the vehicle height adjustment device 25 changes the lengths of the multiple suspension devices 31 of the automobile 1, and adjusts the vehicle height of the automobile 1 to a height corresponding to the operation.

[0049] In step ST26, the control unit 24 records the height of the vehicle body 2 after the manual adjustment in the memory 27. The height of the vehicle body 2 that was last manually adjusted by the driver is recorded in the memory 27 as the last memory.

[0050] In step ST27, the control unit 24 determines whether or not the current vehicle speed of the traveling automobile 1 after automatically switching to the rough road automatic traveling mode is equal to or less than the second speed threshold value. Here, the second speed threshold may be any speed threshold lower than the first speed threshold, for example, 35 km / h. If the current vehicle speed of the automobile 1 is not equal to or less than the second speed threshold, the control unit 24 advances the process to step ST29. If the current vehicle speed of the automobile 1 is equal to or less than the second speed threshold, the control unit 24 advances the process to step ST28.

[0051] In step ST28, the control unit 24 changes the performance of the brake LSD from the first slip suppression brake mode to the second slip suppression brake mode. When the vehicle speed of the traveling automobile 1 after automatically switching to the automatic rough road driving mode falls below a second speed threshold, the control unit 24 changes the performance of the brake LSD to a second slip suppression brake mode without returning the height of the vehicle body 2 from the road surface using the vehicle height adjustment device 25. Furthermore, the control unit 24 internally maintains the setting of the automatic rough road traveling mode.

[0052] In step ST29, the control unit 24 determines whether or not the automobile 1 has finished traveling. For example, when the automobile 1 is stopped and the engine 45 of the automobile 1 is stopped, the control unit 24 may determine that the automobile 1 has finished traveling. In this case, the control unit 24 advances the process to step ST30. On the other hand, if it is not determined that the automobile 1 has finished traveling, the control unit 24 returns the process to step ST21. The control unit 24 repeats the processes from step ST21 to step ST29 until it determines that the automobile 1 has finished traveling. Therefore, while the vehicle is traveling in the automatic rough road traveling mode, the control unit 24 switches the performance of the brake LSD according to the vehicle speed of the vehicle 1, while basically maintaining the vehicle height at a high level without adjusting the vehicle height.

[0053] In step ST30, the control unit 24 cancels the automatic rough road driving mode because the driving of the automobile 1 has ended. The control unit 24 sets the driving mode of the automobile 1 to a normal driving mode or the like.

[0054] In step ST31, the control unit 24 instructs the vehicle height adjusting device 25 to adjust the vehicle height to the height stored in the last memory. The vehicle height adjusting device 25 controls the vehicle height of the automobile 1 to the height stored in the memory 27. The memory 27 stores the height after adjustment in step ST4 in FIG. 3 and the height after adjustment in step ST26 in FIG. 5, whichever is recorded last, as the height in the last memory. Thereafter, the control unit 24 ends this control.

[0055] FIG. 6 is a flowchart of the control for canceling the automatic rough road traveling mode, which is repeatedly executed by the control unit 24 of FIG. While the automobile 1 is traveling, the control unit 24 repeatedly executes the control of canceling the automatic rough road traveling mode shown in FIG. 6 in order to cancel the setting of the automatic rough road traveling mode by driver operation or automatically cancel it.

[0056] In step ST41, the control unit 24 determines whether the current driving mode is the automatic rough road driving mode. If the current driving mode is other than the automatic rough road driving mode, the control unit 24 repeats this process. If the current driving mode is the automatic rough road driving mode, the control unit 24 advances the process to step ST42.

[0057] In step ST42, the control unit 24 determines whether or not the driver has performed an operation to cancel the automatic rough road traveling mode. If the driver is operating the driving mode button 22, the control unit 24 determines that the driver has operated the driving mode to cancel the automatic rough road driving mode, and proceeds to step ST45. When it is determined that the driver has not operated the driving mode button 22 and therefore has not performed any operation by the driver to cancel the automatic rough road driving mode, the control unit 24 advances the process to step ST43.

[0058] In step ST43, the control unit 24 determines whether the vehicle has left the snowy road based on information from the exterior camera 14, the radar device 15, or the near-infrared sensor 17 while driving in the automatic rough road driving mode. If the color of the road surface or lane surface beyond the roadway 103 on which the vehicle is traveling is continuously the color of the road surface itself, the control unit 24 may determine that the vehicle is leaving the snowy road. If the vehicle has left the snowy road, the control unit 24 advances the process to step ST45. If the vehicle has not left the snowy road, the control unit 24 advances the process to step ST44. In addition, the control unit 24 may make an equivalent judgment using other information that can be used to determine whether the vehicle has escaped from a snowy road, such as weather information, detection information from the rain sensor 18, outside air temperature, road surface temperature, snow accumulation map information from a weather server device, etc.

[0059] In step ST44, the control unit 24 determines whether the area in which the vehicle is currently traveling is other than a snow-melting area in which the road heating device 104 is installed. The control unit 24 may determine, for example, based on the current position of the vehicle obtained by the GNSS receiver 12 and the area information of the high-precision map data 13, whether the area in which the vehicle is currently traveling is other than a snow-melting area. Alternatively, for example, the control unit 24 may determine whether the vehicle is in a region other than a snow-melting region by using information obtained by communicating with a server device (not shown) using the vehicle communication device 11. The control unit 24 may also obtain a region determination result from a server device (not shown) via the vehicle communication device 11, and determine whether the vehicle is in a region other than a snow-melting region based on the determination result. If the area in which the vehicle is currently traveling is a non-snow-melting area, but not a snow-melting area, the control unit 24 advances the process to step ST45. If the area in which the vehicle is currently traveling is a snow-melting area, the control unit 24 returns the process to step ST41. The control unit 24 repeats the processing from step ST41 to step ST44 until the determination at any one of step ST42, step ST43, and step ST44 is affirmative.

[0060] From step ST45, the control unit 24 starts processing for canceling the automatic rough road traveling mode. First, the control unit 24 switches the driving mode of the automobile 1 from the automatic rough road driving mode to the normal driving mode. As a result, the control unit 24 returns the driving mode of the automobile 1 from the automatic rough road driving mode to which it has automatically switched back to the normal driving mode.

[0061] In step ST46, the control unit 24 changes the performance of the brake LSD by the VDC device 26 from the second slip suppression brake mode to the first slip suppression brake mode.

[0062] In step ST47, the control unit 24 instructs the vehicle height adjusting device 25 to lower the height of the vehicle body 2 from the road surface. The vehicle height adjusting device 25 controls the vehicle height so that the height of the vehicle body 2 from the road surface becomes the height of the last memory last recorded in the memory 27. Thereafter, the control unit 24 ends this control.

[0063] Through this series of controls, the control unit 24 can determine the road surface on which the road heating device 104 is installed, change the performance of the brake LSD to a setting suitable for overcoming snow bumps, and also change the vehicle height higher. In addition, the control unit 24 can prohibit the driver from adjusting the vehicle height when the automobile 1 is traveling at a reduced speed in an area that includes a snow step at the boundary between a snow-melting section where the road heating device 104 is installed and a non-snow-melting section in order to cross the snow step.

[0064] FIG. 7 is an explanatory diagram of an example of driving of the automobile 1 of FIG. In Figure 7, as shown by the dashed arrow in the figure, automobile 1 starts traveling from a non-snow-melting area outside snow-melting area 100, travels toward snow-melting area 100, travels along roads 106 and 107 in snow-melting area 100, and parks in garage 108 in a parking lot within snow-melting area 100. The automobile 1 starts traveling from a parking garage 108 in the snow-melting region 100, travels along roads 107 and 106 in the snow-melting region 100, travels from the snow-melting region 100 toward a non-snow-melting region, and returns to the starting point.

[0065] A road heating device 104 is installed at an intersection on a one-lane road 106 in a snow-melting area 100 shown in FIG. A road heating device 104 is installed on a side road 107 connected to a road 106 with one lane in each direction. In addition, a road heating device 104 is installed between the garage 108 and the sidewalk 109 of the side street 107.

[0066] In this case, while traveling back and forth between the non-snow-melting area and the garage 108 in the snow-melting area 100, the automobile 1 will alternately travel through sections in the snow-melting area 100 where the road heating device 104 is installed and sections in which the road heating device 104 is not installed. When snow falls so much that it accumulates over the entire snow melting region 100, a snow step is formed at the boundary between the installed section and the non-installed section. On a road 106 with one lane in each direction, snow steps are formed at the boundary between the section where roads are installed at the intersection and the section where roads are not installed around the intersection. At the junction of the one-lane road 106 and the side road 107, a snow step is formed that increases in height from the side road 107 toward the one-lane road 106. A snow step is also formed between the side road 107 and the garage 108 by the sidewalk 109. When traveling from the non-snow-melting region to the garage 108 in the snow-melting region 100 and back, the automobile 1 must travel over a number of snow steps in the snow-melting region 100.

[0067] In the case of a driving environment such as the example in FIG. 7, the driving mode of the automobile 1 is changed from the normal driving mode to the automatic rough road driving mode when the automobile 1 enters the snow-melting region 100 from the non-snow-melting region. The vehicle height of the automobile 1 is raised to the maximum (MAX) and maintained there. The automobile 1 can travel on the roads in the snow-melting region 100 without hitting the vehicle body 2 against snow bumps. Furthermore, while the vehicle 1 is traveling in the snow-melting region 100, the performance of the brake LSD by the VDC device 26 of the vehicle 1 is switched between the second slip suppression brake mode and the first slip suppression brake mode. As a result, the driver does not need to repeatedly adjust the vehicle height or switch the brake LSD performance every time he or she passes over a snowy bump, and can concentrate on driving the vehicle 1 without being bothered by these operations.

[0068] As described above, in this embodiment, the control unit 24 of the control system 10, which functions as an automatic vehicle height adjustment device for the automobile 1, determines whether there is a snow-melting road surface in the direction of travel of the automobile 1, or whether there is a snow-covered road surface caused by the melting snow road surface and the snow-covered road surface, when the automobile 1 is traveling on a snow-covered road surface in a snow-melting area 100 that includes an installation location or installation section where a road heating device 104 for melting snow on the road surface is installed. When there is a melting snow road surface or snow bumps in the traveling direction, the control unit 24 executes control to automatically raise the height of the vehicle body 2 from the road surface. At this time, the control unit 24 does not simply execute control to raise the height of the vehicle body 2, but automatically switches the driving mode of the automobile 1 from the normal driving mode to the automatic rough road driving mode. After automatically switching to the automatic rough road driving mode, the control unit 24 raises the height of the vehicle body 2 while the automobile 1 is traveling on snow. Furthermore, the control unit 24 prohibits the driver from adjusting the vehicle height while the vehicle is traveling after automatically switching to the rough road automatic traveling mode. As a result, the control system 10 serving as the vehicle height adjustment device 25 of the automobile 1 of this embodiment can prohibit the driver from adjusting the height of the vehicle body 2 after automatically executing control to raise the height of the vehicle body 2 of the automobile 1 traveling in the snow-melting region 100. After the automatic height adjustment, the automobile 1 can travel without hitting the vehicle body 2 against snow steps at the boundary between the installation location and non-installation location of the road heating device 104. Moreover, in this embodiment, the height of the vehicle body 2 from the road surface is automatically adjusted to be higher and maintained in that state. The driver does not need to manually adjust the height of the vehicle body 2 every time the road surface alternates between snow-melted and snow-covered, or every time a snow step occurs. The driver can concentrate on driving without being busy adjusting the height of the vehicle body 2, and can drive the vehicle 1 while concentrating on driving in snow melting regions 100 where the road surface alternates between snow-melted and snow-covered, requiring careful driving, or in snow melting regions 100 where repeated snow steps require careful driving.

[0069] In this embodiment, when the vehicle speed of the vehicle 1 during travel after automatically switching to the automatic rough road traveling mode reaches or exceeds a first speed threshold that is equal to or exceeds the speed range of a rough road section with snowy bumps, the control unit 24 changes the performance of the brake LSD from the second spin suppression braking mode to the first spin suppression braking mode while internally maintaining the automatic rough road traveling mode. During this change, the control unit 24 maintains the height of the vehicle body 2 above the road surface without returning it to its original position. This allows the performance of the brake LSD of the vehicle 1 to be set to a setting suitable for traveling on a flat, snowy road. Furthermore, when the vehicle speed of the vehicle 1 during travel after automatically switching to the automatic rough road traveling mode falls below a second speed threshold that is lower than the first speed threshold, the control unit 24 changes the performance of the brake LSD from the first slip suppression braking mode to the second slip suppression braking mode, thereby setting the performance of the brake LSD of the vehicle 1 to a setting suitable for traveling over high slippery snow bumps. In this way, after automatically switching the driving mode of the automobile 1 to the automatic rough road driving mode, the control unit 24 internally retains the setting of the automatic rough road driving mode. Furthermore, the height of the body 2 of the automobile 1 from the road surface continues to be the same as when the mode was automatically switched to the automatic rough road driving mode. Furthermore, during the period of driving in the automatic rough road driving mode, the control unit 24 switches only the performance of the brake LSD, in accordance with changes in vehicle speed, between a first spin suppression brake mode that is suitable for suppressing spin on paved roads, and a second spin suppression brake mode that strengthens spin suppression for both the left and right drive wheels of the automobile 1 and is suitable for passing over large, slippery snow bumps. Furthermore, in the automatic rough road driving mode, which is automatically switched to, the height of the body 2 of the automobile 1 is not adjusted. The height of the body 2 of the automobile 1 is not adjusted every time the road surface alternates between melting snow and snow-covered snow, or every time snow bumps are encountered. On the other hand, if the height of the vehicle body 2 from the road surface is adjusted every time the road surface alternates between melting snow and covered snow, or every time a snow bump occurs, the driver may feel uncomfortable with the repeated height adjustments. In this embodiment, the automatic rough road traveling mode is internally set when the vehicle height is first adjusted, and thereafter, by effectively utilizing the fact that the automatic rough road traveling mode is internally set, it is possible to prevent the height adjustments from being repeated within a short period of time. In this embodiment, it is possible to improve driver comfort.

[0070] In this embodiment, the control unit 24 accepts adjustment of the height of the vehicle body 2 from the road surface by a driver operation when the vehicle speed of the vehicle 1 during travel after automatically switching to the automatic rough road traveling mode is equal to or higher than a first speed threshold, which is equal to or higher than a speed that is not normally used when traveling on a rough road with snowy bumps. As a result, even if the vehicle 1 has automatically switched to the automatic rough road traveling mode and adjustment of the vehicle height by a driver operation is basically prohibited without the driver's knowledge, if the driver determines that there are few driving obstructions such as snowy bumps in the upcoming direction of travel, the control unit 24 respects the operation based on the driver's judgment and allows adjustment of the height of the vehicle body 2 by the driver operation. It is not always good for the automobile 1 to have a tall body 2. For example, when traveling at high speeds on a highway with little snow, lowering the vehicle height can lower the center of gravity and improve vehicle stability. On the other hand, when it is necessary to travel at a low speed and overcome a snowy step, it is desirable to maintain the vehicle height of the automobile 1 as high as possible. In this embodiment, these requirements can be balanced and satisfied.

[0071] In this embodiment, the control unit 24 accepts a driver's operation to switch the driving mode of the automobile 1 even while the automobile 1 is traveling after automatically switching to the automatic rough road driving mode. This allows the driver to cancel the automatically switched automatic rough road driving mode at their own discretion and adjust the height of the vehicle body 2. Furthermore, when the driving mode of the automobile 1 is switched from the automatic rough road driving mode to the normal driving mode by the driver's operation, the control unit 24 changes the performance of the brake LSD from the second slip suppression brake mode to the first slip suppression brake mode. The control unit 24 also lowers the height of the vehicle body 2 from the road surface using the vehicle height adjustment device 25. In this way, when the driver operates to cancel the automatic rough road driving mode, the control unit 24 can return the state of the automobile 1 from the automatic rough road driving mode to its original state. The driver can return the state of the automobile 1 to the state before the automatic rough road driving mode was automatically switched to by simply canceling the automatic rough road driving mode.

[0072] In this embodiment, while driving in the automatic rough road driving mode, the control unit 24 determines whether the automobile 1 has escaped from a snowy road based on information from the exterior camera 14, the radar device 15, or the near-infrared sensor 17. Then, when it is determined that the vehicle 1 has escaped from the snowy road, the control unit 24 returns the driving mode of the vehicle 1, which had been automatically switched to the automatic rough road driving mode, from the automatic rough road driving mode to the normal driving mode. The control unit 24 also changes the performance of the brake LSD from the second slip suppression braking mode to the first slip suppression braking mode and returns it to that mode. The control unit 24 lowers the height of the vehicle body 2 from the road surface using the vehicle height adjustment device 25. This allows the control unit 24 to return to the original state of the automatic rough road driving mode that it automatically switched to, without any driver operation. The driver can easily return the automatic rough road driving mode that was automatically switched to.

[0073] The above-described embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications and changes are possible within the scope that does not deviate from the gist of the invention. [Explanation of symbols]

[0074] 1...Automobile (vehicle), 2...Vehicle body, 10...Control system (automatic vehicle height adjustment device), 11...Vehicle communication device, 12...GNSS receiver (position acquisition device), 13...High-precision map data (regional information providing device), 14...External camera (snow information providing device), 15...Radar device (snow information providing device), 16...Road surface temperature sensor, 17...Near-infrared sensor (snow information providing device), 18...Rain sensor, 19...Outside air temperature sensor, 20...Wheel speed sensor, 21...Vehicle height adjustment button, 22...Driving mode button, 24...Control unit, 2 5...Vehicle height adjustment device, 26...VDC device, 27...Memory, 31...Suspension device, 40...Drive system components, 41...Left front drive wheel, 42...Right front drive wheel, 43...Left rear drive wheel, 44...Right rear drive wheel, 45...Engine, 46...Transmission, 48...Front LSD, 49...Rear LSD, 100...Snow melting area, 101...Garage, 102...Sidewalk, 103...Road, 104...Road heating device, 105...Snow accumulation, 106...One-lane road, 107...Side road (road), 108...Garage, 109...Sidewalk

Claims

1. a vehicle height adjustment device for adjusting the height of a vehicle body from a road surface; a control unit capable of controlling the height of the vehicle body from a road surface by the vehicle height control device in response to an operation by a driver of the vehicle; a position acquisition device for acquiring the position of the vehicle; a local information providing device that provides information on snow melting areas including installation locations or sections where snow melting devices for melting snow on road surfaces are installed; a snow accumulation information providing device that provides information about snow accumulation on a road surface in the traveling direction of the vehicle; and The control unit While the vehicle is traveling on a snow-covered road surface in the snowmelt region, the snow information providing device determines whether or not there is a snow-melted road surface in the traveling direction of the vehicle, or whether or not there is a snow step between the snow-melted road surface and the snow-covered road surface, based on information acquired by the snow coverage information providing device; When the melting snow road surface or the snow step is present in the traveling direction of the vehicle, the driving mode of the vehicle is automatically switched from a normal driving mode to a rough road driving mode; After automatically switching to the rough road driving mode, the vehicle height adjusting device raises the vehicle body above a predetermined height from the road surface while the vehicle is traveling on the snow-covered road surface, After the vehicle is automatically switched to the rough road driving mode, the vehicle height is prohibited from being adjusted by the driver while the vehicle is being driven. Automatic vehicle height adjustment device.

2. The control unit In the normal driving mode, the performance of the brake LSD of the vehicle is set to a first spin suppression brake mode that suppresses spin of either the left or right drive wheel of the vehicle when the vehicle is traveling on a paved road, In the rough road traveling mode, the performance of the brake LSD is set to a second slip suppression brake mode in which slip suppression for both left and right drive wheels of the vehicle is strengthened compared to the first slip suppression brake mode, when the vehicle speed of the vehicle during traveling after automatically switching to the rough road traveling mode becomes equal to or greater than a first speed threshold which is higher than the speed range during rough road traveling, the performance of the brake LSD is changed from the second slip suppression brake mode to the first slip suppression brake mode without returning the height of the vehicle body from the road surface to its original state by the vehicle height adjustment device, When the vehicle speed during travel after automatically switching to the rough road travel mode becomes equal to or less than a second speed threshold that is lower than the first speed threshold, the performance of the brake LSD is changed from the first slip suppression brake mode to the second slip suppression brake mode.

2. The automatic vehicle height adjusting device according to claim 1.

3. The control unit When the vehicle speed during traveling after automatically switching to the rough road traveling mode is equal to or higher than the first speed threshold which is higher than the speed range during rough road traveling, the vehicle height adjustment from the road surface by a driver operation is accepted.

3. The automatic vehicle height adjusting device according to claim 2.

4. The control unit When the driving mode of the vehicle is switched from the automatically switched rough road driving mode to the normal driving mode by a driver operation during driving after the mode has been automatically switched to the rough road driving mode, The performance of the brake LSD is changed from the second slip suppression brake mode to the first slip suppression brake mode, The vehicle height adjustment device lowers the height of the vehicle body from the road surface.

4. The automatic vehicle height adjusting device according to claim 3.

5. The control unit During driving after automatically switching to the rough road driving mode, it is determined whether the vehicle has escaped from the snowy road based on information from the snow accumulation information providing device, If you determine that you are leaving a snowy road, returning the vehicle's driving mode from the automatically switched rough road driving mode to the normal driving mode; The performance of the brake LSD is changed from the second slip suppression brake mode to the first slip suppression brake mode, The vehicle height adjustment device lowers the height of the vehicle body from the road surface.

5. The automatic vehicle height adjusting device according to claim 4.

Images