DE102017218609A1 - A method of emptying a water tank from a fuel cell vehicle - Google Patents

Abstract

The technology disclosed herein relates to a method for draining a water tank of a motor vehicle, comprising the steps of: i) determining the water absorbency of the vehicle ground; and ii) discharging water stored in the water tank onto the vehicle ground if it has been determined that the vehicle ground can receive water.

Description

The technology disclosed herein relates to a method for draining a water tank from a fuel cell vehicle.

Fuel cell vehicles as such are known. They comprise a fuel cell system which provides electrical energy to the motor vehicle. To provide the electrical energy, an electrochemical reaction takes place in the fuel cell stack, in which product water is generated. It is known to store the product water in a water tank of the motor vehicle. It is also known to deliver the product water to the environment. It may happen that accumulate under the motor vehicle greater amount of product water, which may be undesirable.

It is a preferred object of the technology disclosed herein to reduce or eliminate at least one disadvantage of a previously known solution or to suggest an alternative solution. In particular, it is a preferred object of the technology disclosed here to reduce and / or avoid larger accumulations of product water under the motor vehicle or on the road. Other preferred objects may result from the beneficial effects of the technology disclosed herein. The object (s) is / are solved by the subject matter of claim 1. The dependent claims are preferred embodiments.

The technology disclosed herein relates to a method of emptying a water tank. It is preferably a motor vehicle with a fuel cell system.

The technology disclosed herein relates to a fuel cell system having at least one fuel cell. The fuel cell system is intended, for example, for mobile applications such as motor vehicles, in particular for providing the energy for at least one drive machine for locomotion of the motor vehicle. In its simplest form, a fuel cell is an electrochemical energy converter that converts fuel and oxidant into reaction products, producing electricity and heat. The fuel cell includes an anode and a cathode separated by an ion-selective or ion-permeable separator. The anode is supplied with fuel. Preferred fuels are: hydrogen, low molecular weight alcohol, biofuels, or liquefied natural gas. The cathode is supplied with oxidant. Preferred oxidizing agents are, for example, air, oxygen and peroxides. The ion-selective separator can be designed, for example, as a proton exchange membrane (PEM). Preferably, a cation-selective polymer electrolyte membrane is used. Materials for such a membrane are, for example: Nafion®, Flemion® and Aciplex®.

A fuel cell system comprises, in addition to the at least one fuel cell, peripheral system components (BOP components) which can be used during operation of the at least one fuel cell. As a rule, several fuel cells are combined to form a fuel cell stack or stack.

The fuel cell system includes an anode subsystem formed by the fuel-bearing components of the fuel cell system. An anode subsystem may comprise at least one pressure vessel, at least one tank shut-off valve (= TAV), at least one pressure reducer, at least one anode inlet leading to the anode inlet, an anode compartment in the fuel cell stack, at least one anode exhaust conduit leading away from the anode outlet, at least one water purge valve (AWS), at least one anode purge valve (FIG. = APV), at least one active or passive fuel recirculation conveyor (= ARE or ARB) and / or at least one recirculation line and other elements. The main task of the Anodensubsystems is the introduction and distribution of fuel to the electrochemically active surfaces of the anode compartment and the removal of anode exhaust gas.

The fuel cell system includes a cathode subsystem. The cathode subsystem is formed from the oxidant-carrying components. A cathode subsystem may comprise at least one oxidant promoter, at least one cathode feed line leading to the cathode inlet, at least one cathode waste gas line leading away from the cathode outlet, a cathode space in the fuel cell stack, and further elements. The main task of the cathode subsystem is the introduction and distribution of oxidant to the electrochemically active surfaces of the cathode compartment and the removal of unconsumed oxidant.

For example, the water tank to be emptied according to the method disclosed herein may store product water from the cathode exhaust gas and / or anode exhaust gas.

• - Bestimmen der Wasseraufnahmefähigkeit vom Fahrzeuguntergrund; und
• - Ablassen von im Wasserbehälter gespeichertem Wasser auf den Fahrzeuguntergrund unter Berücksichtigung der Wasseraufnahmefähigkeit vom Fahrzeuguntergrund, wobei insbesondere Wasser abgelassen wird, falls bestimmt wurde, dass der Fahrzeuguntergrund Wasser aufnehmen kann.

The method disclosed here for emptying a water tank of a motor vehicle comprises the steps:

• - Determining the water absorbency of the vehicle ground; and
• - Draining water stored in the water tank on the vehicle surface, taking into account the water absorbency of the vehicle surface, in particular water is discharged, if it was determined that the vehicle underground can absorb water.

The vehicle background is the ground on which the motor vehicle drives and / or stands. For example, as the vehicle ground, any type of road surface on which the motor vehicle is traveling, e.g. a paved or unpaved road, farm road, etc. Also to be regarded as a vehicle ground is a place where the motor vehicle is parked, such as a parking garage, a parking lot or a garage. The vehicle background to be determined is not limited to the area on which the motor vehicle is currently standing or driving. The determination of the water absorption capability of the vehicle background includes not only the direct or indirect detection of the current vehicle background but also prognosis of the vehicle background, for example based on weather data, navigation data and / or on the basis of at least one environment detection system, which analyzes, for example, a roadway section in front of the motor vehicle before the motor vehicle enters this lane section.

The water absorption capacity of the vehicle underground can be influenced by various parameters. For example, an unpaved subsoil (e.g., a non-paved farm track) may absorb more water than a paved subsoil (e.g., asphalt). Likewise, the already existing moisture content on the surface of the substrate affects the water absorption capacity. The water absorption capacity thus indicates how much water can still be supplied to the subsoil until the grip of the road surface is too low. For this purpose, corresponding limit values for the terminology can be specified directly or indirectly. The amount of moisture and the water absorption capacity on the road or the vehicle surface depends essentially on the following factors: The environmental conditions: precipitation, air temperature, humidity, wind, radiation balance, the drainage properties of the road (drain roughness, retention and storage capacity, inclination, flow length) the traffic (traffic volume, speeds, traffic composition) and the properties of the roadway structure (heat storage capacity, radiation properties).

In order to determine the water absorption capacity of the vehicle background, various values / values indicative of the water absorption capacity of the vehicle background can be used, which can be compared with corresponding reference values / reference variables.

The method disclosed here may comprise the step of determining the condition of the vehicle ground, in particular the road surface, in order to determine the water absorption capacity. Devices for mounting a condition of a road surface are known in the art. For example, the DE10117351 A1 such a system.

Trocken:

Keine Flüssigkeit auf der Fahrbahnoberfläche (bzw. Flüssigkeitsfilm < 0,01 mm auf der Fahrbahnoberfläche);

Feucht:

Flüssigkeitsfilm >0,01 mm auf der Fahrbahnoberfläche;

Nass:

Flüssigkeitsfilm >0,2 mm auf der Fahrbahnoberfläche;

Extrem nass:

Flüssigkeitsfilm >2 mm auf der Fahrbahnoberfläche; und

Glatt:

Eis, Schnee und Reif bzw. wässrige Lösungen im festen Zustand auch neben Wasser bzw. wässrigen Lösungen befinden sich auf der Fahrbahnoberfläche.

Preferably, the method comprises the step of discriminating whether the vehicle ground is wet, moist or dry. A vehicle ground can be classified as dry if there is no moisture or liquid on the surface of the vehicle ground. A vehicle ground can be classified as moist if moisture is present on the surface of the vehicle underground without a continuous liquid film having formed, at least in areas, preferably under the entire vehicle background. A vehicle background can be classified as wet if so much liquid has accumulated on the surface of the vehicle background that at least partially, preferably under the entire vehicle background, a continuous water film is formed, wherein the water film surface is not interrupted by the surface of the vehicle background. In particular, a vehicle ground may be regarded as wet if the vehicle ground is at least partially reflective. According to DIN EN15518: 2011, the road condition can be quantified as follows:

Dry:

No liquid on the road surface (or liquid film <0.01 mm on the road surface);

Damp:

Liquid film> 0.01 mm on the road surface;

Wet:

Liquid film> 0.2 mm on the road surface;

Extremely wet:

Liquid film> 2 mm on the road surface; and

Smooth:

Ice, snow and frost or aqueous solutions in the solid state also next to water or aqueous solutions are on the road surface.

Vollkommen trocken:

Flüssigkeitsmenge < ca. 10 ml/m² = 0,01 mm;

Feucht oder nass:

Flüssigkeitsmenge > ca. 10 ml/m² = 0,01 mm.

According to the technical delivery conditions for road stations in the 2012 edition (TLS 2012), the condition of the road surface is divided into:

Completely dry:

Amount of liquid <about 10 ml / m ² = 0.01 mm;

Wet or wet:

Amount of liquid> approx. 10 ml / m ² = 0.01 mm.

Preferably, the height of the liquid film is detected by a non-contact measuring method. The height of the liquid film thickness on the surface of the road surface can be determined, for example, by the characteristic reflection of radar or optical radiation (e.g., infrared, microwave radar, laser, etc.). The sensor for determining the height of the liquid film thickness can be provided in the motor vehicle. Alternatively or additionally, such a sensor system may be part of an arrangement for monitoring a road surface.

The method particularly preferably comprises the step according to which it is determined on the basis of at least one environment detection system of the motor vehicle whether the vehicle ground is wet, moist or dry. The environment detection system advantageously comprises one or more of the following components: ultrasound sensor, radar sensor, lidar device, and / or camera device. Likewise, however, any other system which is set up to detect the environment of the motor vehicle can also be used.

The method preferably comprises the step according to which at least one (in particular physical) property of the vehicle background is measured on the basis of the at least one surroundings recognition system of the motor vehicle. For example, it can be measured whether the road surface is wet, humid or dry. For this example, imaging methods can be used. Alternatively or additionally, it can be provided that the surface shape is determined, in particular the surface roughness. If it is recognized, for example, that this is a roadway that has a comparatively low surface roughness, then it can be decided that less water is discharged onto such a roadway than onto a roadway having a higher surface roughness. Alternatively or additionally, the temperature of the vehicle background can be determined. If it is determined that the vehicle ground has a comparatively high temperature, then more product water tends to be released to the vehicle ground.

The method preferably comprises the step according to which the water absorption capacity of the vehicle ground is determined on the basis of weather data and / or data from at least one rain sensor of the motor vehicle. For example, can be determined based on weather data and / or by at least one rain sensor, whether the vehicle surface is wet, damp or dry.

Preferably, the method disclosed herein comprises the step of determining which mass flow of water is deliverable to the vehicle ground. For example, the mass flow of water, which can be delivered to the vehicle underground, be determined depending on the water absorbency of the vehicle surface. For example, can be deposited that a first mass flow of water may be discharged onto a dry vehicle surface, whereas on a wet vehicle surface only a second mass flow of water may be delivered, which is less than the first mass flow of water. The water can be dispensed continuously or at intervals specified by a controller. In particular, the delivery of water can be regulated or controlled taking into account navigation data and / or taking into account the water absorption capacity of future road sections.

Preferably, the method disclosed herein comprises the step of determining the evaporation of water at the vehicle ground. For example, the temperature and / or the moisture content of the ambient air on the motor vehicle can be used for this purpose. Preferably, the mass flow of deliverable at the vehicle surface water can be determined taking into account the evaporation of water on the vehicle surface. In particular, the evaporation of water can be used in addition to the current water absorbency of the vehicle surface. Preferably, the instantaneous evaporation and / or the predicted future evaporation can be used for this purpose.

The drying of the road surface is done by evaporation and Aufwirbelung by crossing vehicle tires. The evaporation is u.a. influenced by air temperature, relative humidity and wind speed.

The method disclosed herein may further comprise the steps of at least also in phases of non-use of the motor vehicle At times, the water absorbency of the vehicle surface is determined, and wherein even in phases of non-use of the motor vehicle water is discharged to the vehicle base, if (especially in the phase of non-use of the motor vehicle) was determined that the vehicle underground can absorb water.

Preferably, the method disclosed herein comprises the step of checking the propensity of the motor vehicle when determining the evaporation. In particular, it can be checked whether the motor vehicle has been parked on a level ground. The inclination of the motor vehicle can be determined for example via a corresponding sensor of the motor vehicle. Such a sensor is familiar to the expert. It can thus advantageously be ensured that the motor vehicle does not erroneously start from an excessively high evaporation rate.

Preferably, during a phase of non-use of the motor vehicle, a control unit and the actuator system controlled or controlled by the control unit can be activated at least temporarily in order to carry out at least one of the methods disclosed here. For example, after a certain time, the control unit could be woken up with the aid of a timer and, with the at least one environment detection system, detect the vehicle background and, if necessary, discharge water again, provided that the vehicle underground can absorb water.

A phase of non-use of the motor vehicle, however, is a respect. Of locomotion inactive phase of the motor vehicle. In other words, the period of non-use is, for example, a (longer) time interval during which the motor vehicle actively receives no instruction from the user that requires the operation of the fuel cell or of the motor vehicle. This is the case, for example, when a motor vehicle is parked.

In other words, the technology disclosed herein relates to a method of emptying a water tank from a motor vehicle having a fuel cell system. It can independently determined the optimal location of emptying a water collection container and then the emptying be initiated. For this, the location can be determined depending on various input parameters. These could be outside temperature, street type, environment, traffic situation etc. The required data for the method can be taken, for example, the on-board computer of the motor vehicle. For example, the water tank could automatically be evacuated where it could not lead to pollution, black ice, or other negative effects (eg, where there are appropriate outlet locations, e.g., at a hydrogen refueling station). Remote could be implemented that the water is not let out where it could freeze according to the outside temperature and accordingly could worsen the road situation. For example. could be predicted on the basis of traffic and weather information suitable places / routes. It may make sense to automatically let out the water before entering the home garage. The users could also be informed if the automatically determined skip is really desired, for example if it could lead to black ice in front of the garage.

The vehicle could use environment detection systems to analyze at least one road characteristic and determine accordingly how much and at which interval water may be discharged, so that the water remains within a certain radius and the ground, for example, is a little humid at most. The motor vehicle could create and follow a kind of exhaust plan, which predicts the evaporation of water accordingly and takes into account measured temperatures (also, in the same place). Thus, a vehicle could fall asleep after the discharge of a certain amount of water and wake up after a certain time with the help of a timer and possibly also check the outlet point (with already existing and built (image) sensors) on moisture and again drain water. (This iterative exhaust process is somewhat reminiscent of power consumption plans in the EMobility area, where the vehicle wants to (re-) load a vehicle and draw up a plan that also takes into account the outside temperature and PV energy.) make a relatively good estimate of the evaporation duration of soil texture and soil and outdoor temperature. (Random, it could be checked whether the water seems to evaporate "too fast", which would speak, for example, for a vehicle inclination.) However, in the vehicle appropriate sensors installed, with which a tilt can be detected and may therefore be dispensed with an emptying This aspect is already contained in another patent specification, as far as I know.) Thus, deliberately small amounts of water could be released without allowing other nearby objects to get wet.

The method disclosed herein may include the step of draining water to the vehicle ground if the vehicle ground is dry. Further, the method may include the step of not draining water to the vehicle ground if the ground is wet. According to one embodiment of the here As the technology disclosed, water is drained to the vehicle ground as long as the ground is dry or wet, but not wet. However, in all the method steps disclosed here, it is also only possible to distinguish whether the vehicle ground is dry or not (= at least moist). In such an embodiment, no product water is discharged when the vehicle ground is not dry.

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

• DE 10117351 A1 [0014]

Claims (11)

Method for emptying a water tank of a motor vehicle, comprising the steps: Determining the water absorption capacity of the vehicle underground; and - Drain water stored in the water tank on the vehicle surface taking into account the water absorption capacity of the vehicle surface. Method according to Claim 1 wherein determining the water absorbency comprises the step of determining the condition of the vehicle subsoil. Method according to Claim 1 or 2 , wherein at least one property of the vehicle background is measured on the basis of at least one environment detection system of the motor vehicle. Method according to one of the preceding claims, wherein it is discriminated in the determination of the state of the vehicle ground, whether the vehicle ground is wet, humid or dry. The method of any one of the preceding claims, wherein determining the water absorbency comprises the step of determining the type of vehicle ground. Method according to one of the preceding claims, wherein the water absorbency of the vehicle surface is determined taking into account - of weather data; and or - data from at least one rain sensor; and or - at least one arrangement for monitoring of a road surface; and or - of at least one driver assistance system. Method according to one of the preceding claims, wherein water is discharged to the vehicle ground, if the vehicle ground is dry, and no water is discharged to the vehicle ground, if the ground is wet. Method according to one of the preceding claims, further comprising the step of determining which mass flow of water can be delivered to the vehicle underground. Method according to one of the preceding claims, further comprising the steps, according to which the evaporation of water is determined on the vehicle underground, and then the mass flow is determined on water deliverable on the vehicle underground, taking into account the evaporation of water on the vehicle underground. Method according to Claim 9 , wherein in the determination of the evaporation, the inclination of the motor vehicle is taken into account. Method according to one of the preceding claims, wherein also in phases of non-use of the motor vehicle at least temporarily determines the water absorbency of the vehicle surface, and wherein also in phases of non-use of the motor vehicle water is discharged to the vehicle base, if it was determined that the vehicle underground can absorb water.