DE102014210103A1 - Detecting a wading ride of a vehicle - Google Patents

Abstract

For detecting a wadership of a vehicle (1), which comprises a chassis with a first axis (12) and a second axis (13), at least one first level sensor (7) is provided which is associated with the first axis (12). Furthermore, at least one second level sensor (8) is provided which is associated with the second axis (13). On the basis of sensor values of the level sensors (7, 8), a decision is made as to whether there is a wading run.

Description

The invention relates to methods and apparatus for detecting a wading ride of a vehicle.

When land vehicles drive or wade due to large accumulations of water, for example when crossing a ford or when flooding on paths or roads, it is essential that a predefined wading depth is not exceeded, up to which proper operation of the vehicle is possible.

From the publication WO 2012/080429 A1 For example, a method and a sensor device are known in which, by means of suitable measurement technology, a subsurface that is being used by a vehicle is scanned in order to determine a water depth through which the vehicle wades. In this case, cameras are described as suitable measuring techniques for a corresponding sensor, as well as sensors which detect water by means of reflection or transmission of a waveform. Geographic data sensors including GPS sensors are also mentioned.

From the publication WO 2012/080430 A1 are described corresponding methods and sensor devices in which the vehicle-driven surface is scanned to determine the depth of water through which the vehicle wades. As suitable measurement techniques for a corresponding sensor, a capacitive measurement or a resistance measurement by means of electrodes as well as an ultrasonic measurement technique are described here.

In the publication WO 2012/080432 A1 a hydrostatic pressure sensor is described by means of which the corresponding water depth is determined under a wading vehicle.

In the publication GB 2 356 602 B a measuring system for a vehicle is described, in which a water-bow wave arising during a wading ahead of the vehicle is detected by means of a radar device or a sonar device. The height of the bow wave can be detected.

It is an object of the invention to reliably detect a wading of a vehicle.

This object is achieved by the invention specified in the independent claims. Advantageous embodiments of the invention are indicated in the dependent claims.

According to a first aspect of the invention, it is provided that, in order to detect a waking movement of a vehicle, which comprises a chassis with at least one height sensor, a decision is made on the basis of sensor values of the level sensor as to whether or not there is a wading movement.

This aspect of the invention is based on the finding that in a wading drive above a certain, vehicle-specific wading depth, a floating movement of the vehicle takes place, which becomes stronger as the depth of the water increases. With this aspect of the invention it was further recognized that such a floating movement can be detected at least until reaching the wading depth with a corresponding level sensor of the vehicle.

In particular, it has been recognized that a wading condition can be detected by the vehicle's float motion, as under such conditions a rebound motion occurs at both the front axle and the rear axle of the vehicle, and so far from usual driving situations, i. situations without wading. The vehicle floats up due to the buoyancy effect. With the invention can be provided in particular, the deflection of suspension elements such. to detect the rebound of springs or shock absorbers. The respective deflection or rebound movement is measured in particular with sensors of the chassis and detected by an evaluation unit. The sensors are preferably located on the wishbones of the chassis, are designed in particular as a potentiometer and can be deflected by lever.

For example, alternative sensor systems can be located directly on the shock absorbers and directly detect the rebound movement as distance measuring sensors and, if necessary, measure the rebound stroke. Advantageously, corresponding sensors and their measuring signals can be used twice, for example additionally for other control tasks, such as, for example, for headlamp leveling in a dipped beam control. With the invention quasi the vehicle can be used as a float, wherein a signal processing can be carried out analogously to known float measuring arrangements.

In the context of the first aspect of the invention, a measuring device for detecting a waking movement of a vehicle, which comprises a chassis with at least one level sensor, can also be specified. In this case, based on sensor values of the level sensor, a decision is made as to whether a wading ride is present. The measuring device has in particular a device for Process the sensor values. It may further comprise one or more means for performing the method steps described herein. With the invention, a correspondingly equipped vehicle, in particular motor vehicle can be specified.

In an advantageous embodiment of the invention, in each case at least one corresponding level sensor is provided both for and in particular on the front axle as well as for the and in particular on the rear axle. As a result, advantageously also a longitudinal inclination of the vehicle can be detected metrologically. Furthermore, at least two level sensors may be provided in particular on each axis. As a result, it is advantageous to detect a transverse inclination of the vehicle by measurement. The level sensors can be provided in particular in the range of suspension spring and / or damping elements of the vehicle. In particular, they can be permanently connected to them.

Advantageously, a plurality of level sensors may also be provided for at least one of the axes, so that different height changes along the axis can be detected. In particular, a plurality of level sensors can each be provided for the front axle and / or for the rear axle, so that height fluctuations caused by cornering and / or acceleration movements can be recognized and can be distinguished from altitude fluctuations caused by wakes. Thus, if advantageously at least two corresponding sensors are provided per vehicle axle, then it can be achieved that a Aufschwimmbewegung the vehicle from a cornering of the vehicle is clearly distinguishable metrologically, because in a Aufschwimmbewegung the height changes along an axis (left or right) to directed up and down the same direction, while they are directed opposite each other when cornering. The same applies to the distinction of a height change caused by a floating motion on the front axle of the vehicle with respect to a pitching motion of the vehicle caused by acceleration. In a Aufschwimmbewegung the changes in level at the front and rear axles are again the same direction, namely upwards, while they are directed opposite to each other in the case of a pitching motion. Accordingly, when the vehicle accelerates on the front axle, a vertical movement or change in height changes upward and at the rear axle a vertical movement downward, while exactly opposite vertical movements occur during braking. These effects can be used advantageously in the context of the invention in an evaluation of the measurement signals of the respective level sensors for the safest possible distinction of the respective vehicle movements.

• – Die maximale, zu durchfahrende Wassertiefe ist in der Regel weder genau bekannt noch genau erfassbar.
• – Die Beschaffenheit des Untergrundes ist unbekannt bzw. nur selten genau einschätzbar. Es kann daher zu einem Einsinken des Fahrzeuges kommen.
• – Unerkannte Hindernisse, Treibgut und Bodenunebenheiten können zu Kollisionen und zum Steckenbleiben führen.
• – Eine Wasserströmung kann schon bei geringer Geschwindigkeit und geringer Wassertiefe das Fahrzeug wegspülen und/oder in einen Bereich versetzen, in dem es nicht mehr manövrierfähig ist und/oder in dem seine Wattiefe überschritten wird, so dass das Fahrzeug zum Beispiel instabil wird oder sein Antrieb ausfällt.
• – Der Auftrieb verringert die Bodenhaftung und somit die Traktion des Fahrzeugs.
• – Je höher die Fahrgeschwindigkeit desto größer ist der Effekt der Aufschwimmbewegung und desto höher wird die Bugwelle und desto größer ist zudem die Gefahr eines Wasserschlags.

In further advantageous embodiments of the invention, it can also be provided that measured values for the water depth present in each case are recorded, because even with sufficient wading capability or wading depth, traversing water accumulations such as, for example, waters or flooded areas is fundamentally risky for a land vehicle. There are various dangers in open terrain, as well as at designated fords and on flooded roads:

• - The maximum, to be traversed water depth is usually neither exactly known nor accurately detectable.
• - The nature of the subsoil is unknown or rarely predictable. It can therefore come to a sinking of the vehicle.
• - Undetected obstacles, flotsam and bumps can lead to collisions and getting stuck.
• - A water flow can even at low speed and shallow water wash away the vehicle and / or place in an area where it is no longer manoeuvrable and / or in which its wading depth is exceeded, so that the vehicle is unstable or its drive, for example fails.
• - The lift reduces the traction and thus the traction of the vehicle.
• - The higher the speed, the greater the effect of the float and the higher the bow wave and the greater the risk of water hammer.

At least part of the measured values for determining the water depth can advantageously be detected with the at least one level sensor. In particular, signals from at least one mechanical, electrical, optical and / or further component such as an ultrasound component, a radar component or a sonar component are used to detect the wading and / or the respective water depth.

Advantageously, a relatively low water level can already be detected with the invention, and in particular at high water levels, a water hammer of the engine can be avoided.

The above-described methods for detecting a wading movement and / or for determining the water depth below and / or next to the vehicle can be supplemented by further measures and thereby further improved with regard to their detection accuracy. For example, can Detecting the Watfahrt of the vehicle additionally be provided on the basis of sensor values representing an electrical variable, the decision to make, whether a Watfahrt exists. The electrical variable may be in particular an electrical resistance. However, it may also be another variable such as a dielectric constant. The electrical variable can in particular be measured and / or evaluated analogously. The particularly analog sensor values may represent an electrical variable in the region and / or on a radiator surface of the vehicle. The sensor can be designed, for example, as a resistance sensor or as a capacitance sensor. The electrical variable can be detected directly on the radiator surface and, in particular, be a size of the radiator surface itself. It can also be arranged on a plurality of provided in the vehicle, in particular close to each other arranged radiator surfaces and / or coolers, each of which is electrically isolated from each other, a sensor for generating corresponding sensor values. The radiator and / or radiator surfaces can also be part of the sensor as such and be configured in particular as a resistance sensor and / or as a capacitive sensor. The radiator surfaces may cooperate to produce the sensor values, respectively. For this purpose, they may in particular be arranged close to one another and / or be insulated from one another electrically. For generating the sensor values, a first radiator surface of a first radiator may form a first electrode of the sensor and a second radiator surface of a second radiator, which is electrically insulated from the first radiator surface, may form a second electrode of the sensor. The first cooler can be a motor water cooler and the second cooler a climate condenser. Further details of these procedures and meter components are provided in the parallel filed by the Applicant German patent application with the internal file number 25860-2 described, the contents of which are hereby incorporated by reference into the present patent application.

It can also be used a camera for water detection. It is also possible to use a light barrier to detect the ride height and / or the water level. Furthermore, a pressure rise in the intake system can be detected by means of suitable pressure sensors and used to detect the wading.

Water and / or a water level can continue to be detected by increasing a driving resistance during the water passage and to their detection, because when driving in water increase compared to a ride in the plane, the driving resistance. This is mainly due to the higher water resistance to air resistance, since water has a higher density. The respective driving resistance can be measured by the drive torque or the drive power of the motor. Disturbing influences such as incline, wind, etc. can be corrected during the processing of the respective measured values.

In order to detect the wading movement and / or to measure a water level or level, it is furthermore possible to use a preferably additional measuring device which comprises a float. It can also be used distance sensors of a parking aid, for example, based on ultrasound measure.

For detecting the wading and / or for determining a water depth in the region of the vehicle, it is also possible to use means, steps, components and / or measures of further methods and devices which are described in the publications mentioned above. These publications are also incorporated herein by reference into this application for this purpose.

The aforementioned further means, components, steps, components and / or measures of further methods and devices represent aspects of the invention, which can also be used independently of the first aspect of the invention mentioned above.

In the context of the invention, it can further be provided that after the detection of a wading movement and / or after the recognition that a water level predetermined by a threshold value is reached or exceeded, protective measures are initiated so that e.g. suction of water into the engine is prevented or e.g. by automatically closing the windows an ingress of water into the interior. By early means of the invention, automatic detection of Watfahrt appropriate measures can already be taken correspondingly early or preventively wholly or partially automatically.

In the following, further embodiments of the invention will be explained in more detail with reference to figures. Show it:

1 A vehicle with various sensors and control units,

2 Ride-height effects of a floatation movement of a vehicle,

3 A measurement arrangement for an electrical variable for water level measurement and

4 Measurements of water level measurements on a radiator surface.

In the in 1 illustrated passenger cars 1 are schematically its engine 2 with a corresponding electronic engine control unit 3 shown. Furthermore, the front axle 12 and the rear axle 13 as well as a front shock absorber 6 and a rear shock absorber 9 from the chassis of the passenger car 1 to see. At the front shock absorber 6 is a level sensor 7 provided with the corresponding height variations of the body of the passenger car 1 can be determined and corresponding height values or height level signals can be output. An appropriate level sensor 8th is on the rear shock 9 intended. The two level sensors 7 . 8th are connected to a control unit 10 connected, which evaluates the respective output level signals or altitude values. The control unit 10 contains a corresponding data processing unit. On the basis of the altitude values and in particular by means of a comparison with reference values and / or with reference function curves, each describing a Aufschwimmbewegung of the vehicle at predetermined speed values, in the control unit 10 be determined whether the passenger car 1 currently located on a wading trip through water and / or how high, if necessary, the water level below the passenger car. With the control unit 10 are typically a variety of other sensors of the passenger car 1 and / or control devices connected directly or indirectly via corresponding interfaces and / or data buses. For example, the controller 10 also with the engine control unit 3 be connected with a slip sensor and / or with a speedometer (speedometer). From these output data can also be used to determine the status of a Watfahrt and / or the water level. Furthermore, it is on a radiator 5 for the engine cooling water in the front area of the passenger car 1 at the bottom of the radiator 5 a sensor 4 provided with the below the radiator 5 located water, especially to the radiator 5 Approaching water can be detected. The sensor 4 can also be designed so that, where appropriate, a water level from below the passenger car 1 located water can be determined. The sensor 4 In particular, it may be an electrical sensor that outputs measurement signals based on capacitance measurements and / or conductivity measurements. On the radiator 5 or on whose outer surface a plurality of corresponding sensors can be provided. In the passenger car 1 If desired, further coolers or cooling surfaces may be provided, on which further corresponding sensors may be provided, for example cooling surfaces of an air conditioning condenser of an air conditioning system. If different radiator surfaces are located close to each other but electrically separated from each other and corresponding sensors are mounted on the different radiator surfaces, then the sensing accuracy can be further increased. Directly in front of the engine cooler 5 is a climate condenser 11 intended. The two facing surfaces of the engine radiator 5 and the climate condenser 11 can also use the capacitive sensor 4 form. For this they can, for example, be located at a distance of 0.2 to 20 centimeters from each other and preferably at a distance of 0.5 to 2 centimeters.

The sensors in the area of the radiator 5 . 11 are connected to a corresponding control or evaluation circuit, for example to the controller 10 ,

In 2 are the ride height effects of a Aufschwimmbewegung a vehicle shown. The graphic symbolically shows a measured value curve 20 for a vehicle speed, wherein the vehicle enters a pool in which it floats. On the time axis applied to the right, the vehicle reaches the point in time 23 the water basin. The measured value curve 21 symbolically represents measured values of a level sensor on the rear axle of the vehicle. The measured value curve 22 symbolically represents measured values of a level sensor on the front axle of the vehicle. From the graph, it can be seen that the height values of a rebound movement are in the negative direction. It can be seen that already at the entrance to the pool by the time 24 a rebound movement takes place on both axes. By accelerating the vehicle up to a maximum speed of about 15 km / h at the time 25 occurs over the initial ride height of the vehicle instead of a conspicuous rebound, wherein the movement at the front axle is stronger than at the rear axle, but otherwise rebound substantially parallel. In comparison, the axes typically move in opposite directions during acceleration and braking in a vehicle movement without water influence and at low speeds, caused by nodding of the vehicle about the vehicle's center of gravity.

By the double arrow 27 the stroke is represented by the spring movement of the front axle of the vehicle. In a practical trial this was 53 millimeters. The corresponding stroke on the rear axle was 23 millimeters.

In order to rule out a false triggering when detecting a wading, other driving situations, which also comes to such a rebound movement, specifically from a Evaluation excluded. It is advantageous, but not essential, to provide sensors for a corresponding level measurement on all four wheels of the vehicle.

For example, when cornering, rolling on one side of the vehicle typically occurs. If level sensors are then mounted on only one side of the axles, sensor signals may be displayed indicating a similar rebound motion. In order to avoid an erroneous assignment of the Watfahrt then, for example, values of steering angle sensors are taken into account in the evaluation. A roll stabilization also has an advantageous effect here.

The ride over a hill can lead to a rebound movement of both axles of the vehicle. It can be largely excluded by a limitation of the speed range in which triggers the function of detecting the Watfahrt, for example, by limiting to the range below 40 km / h, the rebound movement at a crest. Also, the triggering of the function by a rebound motion, which is generated by aerodynamics at high speeds, can thus be effectively excluded.

In 3 is a measuring or sensor arrangement 30 represented for a water level measurement, for example, in the in 1 shown sensor 4 is suitable for a radiator surface. The water level of the water 37 is schematically with the double arrow 38 shown. The arrangement comprises two electrodes 32 . 33 , between the water 37 penetrates. The depending on the water level height changing electrical resistance between the electrodes 32 . 33 is by means of a Wheatstone bridge circuit with corresponding two resistors 35 . 36 , a voltage source 31 , for example, applied to the two electrodes with a voltage of 12 volts and by means of a voltage measuring device 34 detected. Compared to measuring arrangements without a Wheatstone bridge circuit, the shown yet relatively simply constructed arrangement already results in a relatively high measuring accuracy for the respective water level within the electrodes. An adaptation of the measurement accuracy, in particular with regard to different radiator surfaces can be, for example, by adjusting the two resistors 35 . 36 For example, between 1 kOhm and 10 kOhm and / or by adjusting the power supply 31 For example, allow in the range of 6 to 48 V. In order to increase the accuracy further, the contact surfaces of the electrodes 32 . 33 be sized according to your size. The resistance values of the resistances 32 . 33 can also be selected or set advantageous depending on the altitude of the intake in the vehicle.

Furthermore, it is particularly advantageous to have one or more radiator surfaces of existing radiators of the vehicle as one or both electrodes 32 . 33 to use. Incidentally, the radiator surfaces must be correspondingly electrically decoupled. Therefore, cooler surfaces of different coolers are particularly suitable as electrodes. For example, as the first electrode 32 a radiator surface of the engine water cooler can be used and as a second electrode a radiator surface of the air conditioning condenser. The respective radiator surfaces are at a distance to each other, through which their use as electrodes of the measuring arrangement is possible. As a distance, for example, 1.5 centimeters are suitable.

As a result of a water flow between the two radiator surfaces in a Watfahrt the two radiators are electrically connected. Depending on the level of the water and correspondingly through-flow area of the two radiator surfaces, the voltage drop changes. This allows the height of the water level to be measured. An advantage of such an arrangement may further be when the suction of an internal combustion engine is located directly on the cooling surface for the engine cooling at an elevated position. As a result, if necessary, the water level can already be detected when rising before reaching the intake duct and appropriate countermeasures can be taken.

In 4 are schematically measuring signals one of 3 corresponding electrical sensor whose first electrode is a radiator surface of the engine water cooler and the second electrode is a radiator surface of a directly behind the engine water radiator arranged air conditioning condenser. The vehicle enters a water basin via a ramp, the water level of which reaches above the lower edge of the respective radiator surfaces. The curve 40 shows the corresponding speed of the vehicle. The curve 41 shows the measured values of the sensor arrangement. At the time 42 The vehicle reaches the water basin, so that water penetrates between the cooler surfaces. Due to the bow wave in the front area of the vehicle, which arises when entering the water basin, the measuring signal rises sharply. Shortly after the time 42 the vehicle is stopped in the water basin, resulting in the time 42a until the time 43 the bow wave breaks down a bit and the water level drops between the cooler surfaces. As a result, the measurement signal drops again. From the moment 43 it rises again, because the vehicle has been set in the meantime from the state again in motion and is further accelerated, causing the bow wave rises again. By a subsequent braking of the vehicle, the bow wave runs away from the vehicle forward, whereby the measurement signal in turn until the time 44 falls sharply.

In the following, effects that are relevant for measuring methods in which a wading and / or a water level are measured on the basis of the driving resistance will be described. When driving in water, the driving resistance increases compared to driving on a dry road. This is mainly due to the higher water resistance to air resistance, since water has a higher density. The driving resistances can be measured, for example, by the drive torque or the driving power of the engine in a motor vehicle including an electric vehicle. However, interfering influences must be taken into account in order to obtain an accurate measurement result. For example, it is necessary that driving situations, which also cause a driving resistance increase, are detected and excluded. Disturbing influences and possibilities to recognize these are for example:
Ascent: Detect by inclination sensor or level sensor.
Trailer: recognizable by electrical connection.
Headwind: plays a role mainly at higher speeds.
Curve resistance: Can be detected by the steering angle sensor.
Loose ground: Recognizable with the wheel speed sensors.
Loading conditions: Should be excluded by application on possible or permissible loading conditions.
Flat tire: detectable with wheel speed sensors.
Acceleration: detectable with accelerometer or speed sensor.
Driving through snow: Recognizable by measuring the outside temperature, eg by means of an upper threshold in the range between -5 and +5 degrees Celsius.

The described devices and system components are in particular controlled by computer programs and can have further, known per se elements of computers and digital control devices such as a microprocessor, volatile and non-volatile memory, interfaces, etc. Therefore, the invention can also be implemented in whole or in part in the form of a computer program product which, when loaded and executed on a computer, completely or partially effects a sequence according to the invention. It can be provided, for example, in the form of a data carrier such as a CD / DVD, or else in the form of one or more files on a server from which the computer program can be downloaded.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2012/080429 A1 [0003]
• WO 2012/080430 A1 [0004]
• WO 2012/080432 A1 [0005]
• GB 2356602 B [0006]
• DE 25860-2 [0019]

Claims (11)

Method for detecting a waking movement of a vehicle ( 1 ), which has a chassis with a first axle ( 12 ) and a second axis ( 13 ), wherein at least one first level sensor ( 7 ) of the first axis ( 12 ) and at least one second level sensor ( 8th ), that of the second axis ( 13 ), based on sensor values of the level sensors ( 7 . 8th ) a decision is made as to whether or not there is a wading trip. A method according to claim 1, characterized in that measured values are recorded for each existing water depth. Method according to one of the preceding claims, characterized in that the first axis ( 12 ) is a front axle and the second axle ( 13 ) a rear axle and that both for the front axle ( 12 ) as well as for the rear axle ( 13 ) at least one respective level sensor ( 7 . 8th ) is provided. Method according to claim 3, characterized in that for the front axle ( 12 ) and / or for the rear axle ( 13 ) each a plurality of level sensors ( 7 . 8th ) are provided, so that caused by cornering and / or acceleration rides altitude fluctuations are distinguishable and watertight height variations. Method according to one of the preceding claims, characterized in that the level sensors ( 7 . 8th ) each in the range of suspension, spring, and / or damping elements ( 6 . 9 . 12 . 13 ) of the vehicle ( 1 ) are provided. Method according to one of the preceding claims, characterized in that for detecting the wading and / or the respective water depth signals from at least one mechanical, electrical, optical and / or further component such as an ultrasound component, a radar component or a sonar Component to be used. Method according to one of the preceding claims, characterized in that the height sensor ( 7 . 8th ) has at least one mechanical, electrical, optical and / or further component such as an ultrasound component, a radar component or a sonar component and that are used to detect the Watfahrt signals of the other component. Measuring device for detecting a waking movement of a vehicle ( 1 ), which has a chassis with a first axle ( 12 ) and a second axis ( 13 ), comprising: - at least one first level sensor ( 7 ), the first axis ( 12 ) and - at least one second level sensor ( 8th ), the second axis ( 13 ), based on sensor values of the level sensors ( 7 . 8th ) a decision is made as to whether or not there is a wading trip.  Measuring device according to claim 8, comprising means for carrying out a method according to one of claims 1 to 7.  Measuring device according to claim 8 or 9, comprising at least one mechanical, electrical, optical and / or further component such as an ultrasonic component, a radar component or a sonar component and a device for processing the sensor values.  Vehicle comprising a measuring device according to one of claims 8 to 10.

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