DE102014210104A1 - Detecting a wading ride of a vehicle - Google Patents

Abstract

In order to detect a waking movement of a vehicle (1), a decision is made on the basis of sensor values representing the one electrical variable as to whether or not there is a wading movement.

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, for the purpose of detecting a wading, a decision is made on the basis of sensor values representing an electrical variable as to whether or not there is a wading movement.

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. In particular, the evaluation of the measurement signals can also be completely or partially digital. The electrical variable may in particular be an electrical resistance. However, it may also be a different size, e.g. be a dielectric constant. The sensor can accordingly be designed, for example, as a resistance sensor and / or as a capacitance sensor. The electrical size can be detected directly on the radiator surface. For this purpose, the sensor may, for example, be attached to the radiator surface and in particular comprise the radiator surface.

The first aspect of the invention is based on the recognition that the cooler surfaces for detecting sensor signals for detecting a wading are an advantageous location, in particular if the respective sensor is mounted at the level of the lower end or the lower edge of the cooler surface. In particular, the sensor can be fastened directly to the lower end or to the lower edge. As soon as water reaches the sensor, it can generate appropriate measuring signals. Due to the wetting of the sensor or a corresponding sensor surface, in particular their conductivity changes. With the first aspect of the invention, it was further recognized that the change in conductivity can be detected at least until reaching the wading depth with a corresponding conductivity sensor of the vehicle.

The invention is further based on the knowledge that it is relatively easy to make a decision based on the detected electrical variable as to whether or not there is a wading movement. It is particularly advantageous if a measured value of the electrical variable can be used directly for a comparison with one or more reference or threshold values, so that, for example, directly from the value of a measured resistance can be concluded by means of the comparison on whether a Watfahrt exists. On the basis of corresponding sensor values for the electrical variable, it can even be achieved that the respective present water level can be determined. It is possible to make the decision to Watfahrt and especially the water level alone on the basis of an electrical variable and thus in particular based on a single sensor value or to determine. As a result, it may not be necessary in particular to use a plurality of sensors and / or a plurality of sensor values.

The radiator surface of the vehicle may be provided in particular in the front region of the vehicle or on the vehicle front or directly behind the front bumper. It may be a radiator surface of an engine radiator or another radiator surface, for example of a climate condenser. The lower edge of the respective radiator can be arranged above a vertical vehicle axis above, in particular just above the bottom plate.

In a preferred embodiment of the invention, in each case a sensor for generating corresponding sensor values is arranged on a plurality of radiator surfaces and / or radiators provided in the vehicle, in particular close to one another, which are each electrically insulated from one another. The radiator and / or radiator surfaces can also be part of the sensor as such and be designed, in particular, as a capacitive sensor and / or as a sensor for an electrical resistance. 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 radiator can be, for example, a motor water cooler and the second radiator a climate condenser. For example, the sensor can also be wholly or partly mounted in the region of a radiator on the vehicle frame. For example, a first electrode of the sensor may be attached to or formed by the vehicle frame, and a second electrode of the sensor may be attached to or formed by a radiator surface.

On the basis of a comparison of the sensor values of different sensors, which are electrically separate from one another and independent of one another, an even higher accuracy can be achieved when detecting the wading movement and / or when measuring a water depth below the vehicle than when using only one sensor.

The sensor for detecting the electrical variable may in particular comprise a bridge circuit and / or an electrode arrangement. The sensor can be designed so that water, which penetrates between the electrodes, changes the capacitance of the sensor and / or the electrical resistance between the electrodes. In each case, a current flow, a resistance, a voltage drop and / or another typical measured variable can be detected. In an advantageous embodiment of the invention, a change in the electrical resistance is measured by means of a bridge circuit and these measurement signals used to detect the Watfahrt. The electrodes of the sensor can in particular be designed or electrically connected such that they are electrically separated from the vehicle ground and / or from the radiator surface. The sensor may also be configured to measure a change in the electrical capacitance of the electrode assembly and to that end, known circuit components, such as those shown in FIG. an alternating voltage source.

By the first aspect of the invention, a corresponding measuring device for detecting a Watfahrt of a vehicle, which includes a radiator surface, can be specified. The measuring device comprises a sensor for detecting an electrical quantity, such as an electrical quantity. an electrical resistance or an electrical capacitance in the region of the cooler surface. Based on sensor values generated by the sensor, a decision is made as to whether or not there is a wading. In particular, the measuring device has a device for processing the sensor values. It may further comprise one or more means for performing the method steps described herein. In the context of the invention, a correspondingly equipped vehicle, in particular motor vehicle can be specified.

• – 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 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 capacity or wading depth, it is fundamentally risky for a land vehicle to traverse water accumulations such as, for example, waters or flooded areas. 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.

With the invention, these dangers can be advantageously reduced. At least part of the measured values for the water depth can advantageously be detected with the at least one level sensor.

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.

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.

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, to detect the wading of the vehicle, it may additionally be provided that a chassis provided in the vehicle has a first axis and a second axis and that at least one first level sensor is provided, which is assigned to the first axis and at least one second level sensor is provided, which is assigned to the second axis. In this case, based on sensor values of the level sensors, a decision can be made as to whether a wading ride is present. Furthermore, it can be advantageously provided, the deflection of suspension elements such. to detect the rebound of springs. Advantageously, a plurality of level sensors may be provided for at least one of the axes, so that different height changes along the axis can be detected. Further details about these method measures and corresponding measuring device components are described in the German patent application filed in parallel by the Applicant with the internal file number 25860-1, the contents of which are hereby incorporated by reference into the present patent application. The level sensor may be formed as a distance sensor having mechanical, electrical and / or optical components.

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 used to detect them, 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 a wading and / or a water level, a preferably additional measuring device may be used, 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 for this purpose are also incorporated herein by reference into the present application.

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, in particular the wading depth of the vehicle, 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 in which it comes to such a rebound movement, specifically excluded from a rating. 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 suitable as electrodes especially cooler surfaces of each different cooler. 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 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 motion in the meantime from the state and is further accelerated, causing the bow wave increases 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 trip: Detected by electrical connection. To wind: Plays a role mainly at higher speeds. Curve resistance: Can be detected by the steering angle sensor. Loose underground: Recognizable with the wheel speed sensors. Load conditions: Are by applying to possible or permitted To exclude loading conditions. Flat tire: Can be detected with wheel speed sensors. Acceleration: Detectable with accelerometer or speed sensor. Drive 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. The invention can therefore 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 implements a sequence according to the invention causes. 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]

Claims (12)

Method for detecting a waking movement of a vehicle ( 1 ), wherein based on sensor values representing an electrical quantity, a decision is made as to whether or not there is a wading. A method according to claim 1, characterized in that the electrical quantity is an electrical resistance or an electrical capacity. Method according to claim 1 or 2, characterized in that several in the vehicle ( 1 ) provided, in particular close to each other arranged radiator surfaces, which are each electrically insulated from each other, each cooperate to generate the sensor values. A method according to claim 3, characterized in that for generating the sensor values, a first radiator surface of a first radiator ( 5 ) forms a first electrode and a second radiator surface of a second radiator ( 11 ) electrically isolated from the first radiator surface forms a second electrode. Method according to claim 4, characterized in that the first cooler ( 5 ) is a motor water cooler and the second radiator is a climate condenser ( 11 ) and that the two coolers ( 5 . 11 ) are electrically isolated from each other. Method according to one of the preceding claims, characterized in that the sensor values are measured by means of a sensor ( 30 ), which comprises a bridge circuit and / or an electrode arrangement. Method according to one of claims 4 to 6, characterized in that by water between the electrodes ( 32 . 33 ) penetrates the electrode assembly, the electrical capacitance of the electrode assembly and / or the electrical resistance between the electrodes are changed and the change is detected by metrology and evaluated. Method according to one of claims 4 to 7, characterized in that the electrodes ( 32 . 33 ) of the sensor ( 30 ) are electrically connected so that they are electrically isolated from the vehicle mass and / or at least one of the radiator surfaces. Method according to one of the preceding claims, characterized in that measured values are recorded for each water depth present. 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. Measuring device for detecting a waking movement of a vehicle ( 1 ), comprising a sensor ( 30 ), whereby by means of the sensor ( 30 ), which represent an electrical quantity, a decision is made as to whether there is a wading.  Motor vehicle comprising a measuring device according to claim 11.

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