WO2014193294A2

WO2014193294A2 - System and method for level measurement of liquids

Info

Publication number: WO2014193294A2
Application number: PCT/SE2014/050636
Authority: WO
Inventors: Fredrik Brandt
Original assignee: Scania Cv Ab
Priority date: 2013-05-31
Filing date: 2014-05-23
Publication date: 2014-12-04
Also published as: SE538093C2; WO2014193294A3; SE1350664A1

Abstract

The present invention provides a method and a system for level measurement of liquids in a mobile device. The system comprises a measuring device, which is arranged for a first measurement of at least one first liquid level in a first container for liquids arranged in the mobile device. The system also comprises a first determination device, which is arranged to determine an impact which at least one ambient factor may have on the measurement of the liquid level, wherein the at least one ambient factor influences the mobile device in such a manner that the measuring values are impacted. The system also comprises a second determination device, which is arranged to determine whether the level measurement is reliable. The determination of the measuring value's reliability is based, according to the invention, on the impact which the at least one ambient factor has had on the level measurement's measuring values.

Description

The present invention pertains to a method for level

measurement of liquids in a mobile device according to the preamble to claim 1. The present invention also pertains to a system arranged for level measurement of liquids in a mobile device according to the preamble to claim 22, and a computer program and a computer program product, which implement the method according to the invention. Background

The following background description constitutes a description of the background to the present invention, and thus need not necessarily constitute prior art.

Mobile devices, that is to say for example vehicles or

'vessels, such as ships, aeroplanes or other mobile devices, often comprise one or several containers for liquids. These liquids may comprise liquids which are required for the propagation of the mobile device, for example fuel, coolant, washer fluid, different types of lubricants, such as engine or gearbox oils, hydraulic liquids, or additives for exhaust purification, for example comprising urea or other reducing agents. The liquids may also comprise other types of liquids which are not important for the propagation of the vehicle itself. For example, the containers may comprise drinking water or other beverages . The containers may also be transport containers, in which liquids are transported in the mobile device . It should be realised, that liquids which are

transported by the mobile device may be basically of any type, for example chemical liquids, oil for heating, or food

liquids, since a transport container may be filled with substantially any liquid whatsoever. In this document, the invention will be discussed mainly regarding its application in vehicles. A person skilled in the art will realise, however, that the invention may also be implemented in substantially all types of mobile devices in which liquids are comprised in containers, for example the above mentioned vehicles, vessels and aeroplanes.

Containers for liquids often comprise a measuring device, which is arranged to measure the liquid level for the liquid in the container, since it is often important to know how much liquid is in the container. For example, in relation to the liquids which are important, for the propagation of the mobile device, it is important to know how much fuel, lubricant, washer fluid and/or coolant remains in the respective

container in the mobile device. Therefore, the containers in the mobile device are often equipped with a measuring- device comprising one or several of a. float, an ultrasound sensor or some other device which may register and report a liquid level in the container. The measured liquid level may then be used to determine an

available volume of liquid in the respective containers.

For mobile devices comprising an engine, it is for example entirely decisive to be able to rely on the fact that there is sufficient engine and gearbox oil in order to sufficiently lubricate the engine and the gearbox, respectively. There is also, according to certain regulatory requirements, an

obligation to correctly be able to measure the consumption of reducing agent, such as urea or AdBlue, in order to prove that sufficient exhaust purification has been carried out .

For liquids which are transported in a transport container in the mobile device, it is important to be able to monitor the liquid level in the container, in order to be certain that the container is watertight . This applies in particular to

transport of liquids harmful to health, such as different types of chemicals.

Brief description of the invention

For mobile devices comprising one or several liquid containers with measuring devices, it is difficult to correctly

interpret, at individual measuring occasions, what actual liquid level really is represented by a measuring signal, qenerated by a rneasurinq device for measurement of a liquid level in a container. This is because the measuring value for the liquid level at the measurinq time and/or at the measuring point is sometimes higher/lower than it should be, because the liquid in the container sloshes around in the container and/or has a non-horizontal surface. This sloshing and/or this non- horizontal surface may for example be due to the mobile device accelerating or retarding, or for example, to a vehicle comprising the container being located on an uphill slope.

Previously this problem has been resolved by the measuring ^'values from the measuring device forming average values over time. The idea is then that the rare inaccurate values have a small and, for the measurement, insignificant impact on the averaged value for the liquid level if the averaging is carried out over a sufficiently long time. Thus, these prior art solutions have always calculated an average value for the liquid level over a relatively extended time period, in order to avoid rare inaccurate values for the liquid level to cause faults in the mobile device, such as alarm signals, faulty system contro 1 and similar .

However, it is not always advantageous to average these level measurement values over time periods. The averaging

distributes inaccurate values over the time period for which the averaging is carried out. This also entails that actual (non-inaccurate) values are also distributed over this time period in a similar manner, which means that the averaging of the level measuring values risk to "conceal" actual diverging values by being weighted together with all other values during the time period. Thus the averaging provides a time delay, which means that a guick actual change of the level measuring ^'values will provide a delayed changed average level value.

For example, in relation to a quickly falling level for the engine, gearbox or braking oil it is important that control and alarm systems in the mobile device may as soon as possible determine whether the level is actually falling quickly, in order to initiate measures that protect the mobile device and/or a driver and potential passengers .

It is therefore one objective of the present invention to provide a method and a system for level measurement of liquids in a mobile device which correctly identify inaccurate

measuring values and correct measuring values, respectively.

This objective is achieved through the above-mentioned method in accordance with the characterising portion of claim. 1. The objective is also achieved through the above-mentioned system according to the characterising portion of claim 22, and the above mentioned computer program and computer program product.

Through the method and the system according to the present invention, a plausibility analysis is obtained as to whether the measuring signal/measuring value is impacted by ambient factors, which may be used in order to increase the accuracy of the measuring values for the liquid levels.

Through the use of the method and the system according to the present invention, the reliability of the measurement of the liquid level may be determined, based on whether the mobile device is impacted by ambient factors. Subsequently the measurement may be used with consideration for the determined reliability, Thus, the measurement may be interpreted based on the

reliability which results from the potential impact from outside, which means that, gains in precision and/or time may be made for the measurements of liquid levels in the mobile device. This increased speed and/or precision may mean that damage to the mobile device and/or a driver and/or passengers in the mobile device may be avoided.

Thanks to the present invention non-reliable measuring values may be given special treatment, for example by being ignored or by less consideration being given to these non-reliable measuring values, which reduces the risk of inaccurate

decisions being taken, based on non-reliable measuring values. Thus, the use of false level detections may be avoided through the present invention.

The present invention thus results in a totally seen higher quality of the decisions which are taken by control

devices/control systems in the mobile device. In addition, quick changes in the liquid level may also be tracked when the present invention is used, which reduces the risk of for example engine failure due to fast leakage of engine oil, or for gearbox failure due to fast leaking gearbox oil, since the quickly falling oil level will certainly be discovered, so that suitable measures, such as protective control measures and/or alarms may be carried out in order to ensure that the engine/gearbox is protected. According to one embodiment of the present invention, the determination of the impact, which the at least one ambient factor has on the measuring values for the liquid level in the first container, is based on a second measurement of at least one second liquid level in at least one second container for liquids arranged in the mobile device. If the measuring values for the first container and for the at least one second container change substantially similarly, a conclusion may be drawn that the ambient factors reasonably impact the measuring values, since the ambient factors impact all containers in the mobile device. Thus, the measuring values in this case may be determined as non-reliable since they are impacted by at least one ambient factor. This embodiment may be implemented with very little added complexity, since several liquid containers in current mobile devices, such as for example in vehicles, often are already equipped with measuring devices. The present invention may therefore increase the precision of measurements and/or decisions in the mobile device, with very little added manufacturing cost and/or com 1exity .

The invention will be illustrated in more detail below, along with the enclosed drawings where similar references are used fo ' similar parts , and where:

Figure 1 shows a mobile device exemplified as a schematic vehicle ,

Figure 2 shows a flow chart for the method according to the inve ion,

Figure 3 shows a schematic container with measuring points,

Figure 4 shows a control device according to the present invention . Figure 1 shows schematically an example vehicle 100 comprising the present invention. The vehicle 100, which may be a

passenger car, a truck, a bus or another vehicle, comprises a drive line, which conveys power to driving wheels 113, 114 in the vehicle 100. The drive line comprises one combustion engine 101, which in a customary manner, via an output shaft

102 on the combustion engine 101, is connected to a gearbox

103 via a clutch 106. The combustion engine 101 is driven by fuel from a fuel tank 130, which is supplied to the combustion engine 101 via a fuel conduit 131, such as a nose or similar. The engine 101 is lubricated by engine oil, which is collected in an oil pan and distributed within the engine 101 by the engine's internal parts when these rotate within the engine 101. The gearbox 103 is lubricated by a gearbox oil, which is directly available in the space in the gearbox where the shafts and cogwheels are located, and which is distributed within the gearbox 103 when its cogwheels and shafts rotate.

An output shaft 107 from the gearbox 103 drives the wheels 113, 114 via a final drive 10S, such as e.g. a customary differential, and the drive shafts 104, 105 connected to the said, final drive 108.

The vehicle 100 also comprises an exhaust treatment system 120 for treatment /pu ification of exhaust emissions resulting from combustion in the combustion chamber of the combustion engine 101. The exhaust treatment system 120 may comprise a container for the reducing agent 121, in which for example urea or AdBlue are stored and supplied to the exhaust,

treatment system 120 during its exhaust purification. The combustion engine 101 is controlled by the vehicle's control system via a control device 150. Likewise, the clutch 106 and the gearbox 103 may be controlled by the vehicle's control system with the help of one or more applicable control devices (not shown) . Naturally, the vehicle's drive line may also be of another type, such as a type with a conventional automatic gearbox, of a type with a hybrid drive line, etc.

The control device 150 according to the present invention also comprises a. first, determination device 151 and a second determination device 152 and is connected to, and obtains measuring signals from, at least one measuring device for the measurement of a liquid level in a container in the vehicle. The first determination device 151 and the second

determination device 152 are described in more detail below. In the example in figure 1 the control device 150 is connected to a measuring device for level measurement of engine oil in the engine 101, to a measuring device for level measurement of the gearbox oil in the gearbox 103, to a measuring device for level measurement of the fuel in the fuel tank 130 and to a measuring device for level measurement of the reducing agent in the tank for reducing agent 121. The control device 150 is also connected to a measuring device for level measurement of at least one additional liquid in at least one additional container 140, which for example may consist of one or several of washer liquid, coolant and liquid in a transport tank in the vehicle. A person skilled in the art will also realise that substantially any type of liquid container containing substantially any type of liquid measured by a measuring device may be connected to the control device, to provide measuring signals for liquid levels to the control device 150.

Figure 2 shows a flow chart for the method according to the present invention. In a first step 201 of the method, a first measurement of at least one first liquid level in a first container for liquids is carried out, where this first container is arranged inside the mobile device. For example, the level for engine oil in the engine 101 in a vehicle 100 may here by measured by its measuring device.

In a second step 202 of the method, an impact which at least one ambient factor may have on the first measurement in step 201, is determined. The at least one ambient factor here consists of an ambient factor which impacts the mobile device. For example, the ambient factor may here consist of a road gradient for a road section on which a vehicle 100 is located. In a third step 203 of the method according to the present invention, it is determined whether the first measurement in the first step 201 is reliable. This determination of the reliability for the first, measurement, is based on the

determination of the impact which is made in the second step 202 of the method.

Through the method according to the present invention , the reliability of the first measurement of the liquid level may be determined based on whether the mobile device is impacted by ambient factors, following- which the measurement may then be used with consideration of the determined reliability. In other words, it is determined whether the mobile device is impacted from the outside, following which the measuring signal/measuring value from the measuring device is

interpreted based on the reliability which results from the potential impact from outside. When the present invention is applied, gains may thus be made in precision and/or time regarding the measurements of liquid levels in the mobile device .

Thus non-reliable measuring- values may be treated separately, for example by being ignored or by these non-reliable

measuring values being given less consideration. Thus, the risk that decisions are made based on non-reliable measuring values is considerably reduced. This provides an overall higher quality of decisions. In addition fast changes in liquid levels may be tracked when the present invention is used, which reduces the risk of, for example, engine failure due to fast leaking engine oil.

Prior art attempts of solutions to problems with liquid level measurements have resulted in considerable work and

considerable manufacturing costs being invested in various optimisations of contai er geometries and/or placements of measuring points in containers, in order to minimise the impact of ambient factors. With the use of the present

invention this problem may instead be handled in the software of control devices/control systems, which is a considerably less labour-intensive and less costly solution to the problem.

According to one embodiment of the present invention, the det.ermina.tion of whether at. least one ambient factor impacts the measuring values may be based on a gradient a which the mobile device experiences when the measurement is carried out. This gradient a may be either in the travelling direction of the mobile device and/or at an angle in relation to the travell ing directio ,

Where the mobile device is a vehicle, the gradient may consist of the road gradient ex for 3. O3.G section on which the vehicle is located. The road gradient a may then constitute the gradient along the vehicle's travelling direction and/or the road gradient a at an angle in relation to e.g. a right angle to the vehicle ' s travelling direction. The direction of the road gradient a may be significant to the road gradient's impact on the liquid level measurement, since the liquid container in which the measurement is carried out may have a geometrical design and/or may have a placement of the

measuring device, which means that the measurement is more sensitive to gradients in one direction than in another direction. If for example the measuring point, such as for example the float or the ultrasound device, is placed at one end of the container in the travelling direction, but

centrally in one direction at a right angle to the travelling direction, this may mean that the road gradient a: in the travelling direction has a greater impact, on the measurements than the road gradient a across the travelling direction. This is described in more detail below.

The road gradient a may be determined/measured by the vehicle itself, for example by using an accelerometer, a power

equation and/or an elevation change. In systems where

information exchange between vehicles is used, the road gradient a and/or information related to a road gradient a estimated by a vehicle may also be provided to other vehicles, either directly, or via an intermediate unit such as a

database or similar. Thus the road gradient a: may then be determined based on information provided by another vehicle.

The road gradient a: may also be determined based on

topographical map data, for example map data from digital cameras comprising topographical information. Often

positioning information, such as GPS-information (Global

Positioning System), is used in the determination. With the help of positioning information the vehicle's position in relation to the map data may be determined, so that the road gradient may be extracted from the map data. The positioning information may also be based on radar information, on camera information, on information from another vehicle, on

positioning information previously stored in the vehicle. Current topographical maps, and also current positioning systems, have high accuracy, which means that ambient factors which depend on the road gradient a may be determined quickly and accurately in the vehicle. The road gradient a may also be determined based on

positioning information and road gradient information

previously stored in the vehicle, or on information obtained from traffic systems related to said road section.

In several cruise control systems today, map data and

positioning information is used in the cruise control. Such systems may then provide map data and positioning information to the system for the present invention, which means that the added complexity for the determination of the road gradient o: is minimised. The gradient which the mobile device experiences may also consists of a terrain gradient a if the vehicle is located in terrain, that is to say outside the road network, for example if the vehicle is a tractor or another terrain vehicle.

The gradient which the mobile device experiences may also consist of a water gradient a caused by said mobile device in interaction with one or several formations of water, for example waves, if the mobile device is a water vessel, such as a ship, which is located in/on water.

Similarly, the gradient, which the mobile device experiences may also consist of an air gradient a, which is caused by the mobile device's interaction with air. The mobile device for this embodiment is typically a flying vessel, such as an aeroplane or a helicopter, which is in the air.

According to one embodiment the at least one ambient factor which impacts the vehicle is dependent on how the vehicle is driven. Therefore, the determination of what impact the at least one ambient factor may have on the measurement of the liquid level may be based on the driving of the vehicle.

If the vehicle is accelerated, this causes an ambient factor which impacts the measurement, since liquids in containers in the ^'vehicle move due to the acceleration. The vehicle's acceleration may here thus interact with the cont.ainer ' s design and potential objects, for example exhaust means, in the container. Typically, wave formations arise in the

vehicle's travelling direction in the containers when the vehicle accelerates, which means that the liquid level which the measuring device determines may not be consistent with the actual liquid level in the container.

A slow and/or even acceleration often causes minor wave formations in the containers than quick and/or jerky/uneven accelerations. Thus, it may happen that a slow and/or even acceleration may be deemed to provide reliable measuring values, while fast and/or jerky/uneven accelerations provide non-reliable measuring values.

Similarly, retardations of the vehicle impact the measurement of liquid levels in the vehicle's liquid containers, since wave formations are then also created in the containers. Here as well, a slow and/or even retardation may provide reliable measuring values, while fast and/or jerky/uneven retardations provide non-reliable measuring values.

Thus, according to the embodiment the reliability for the first measurement may be determined based on whether the vehicle accelerates/retards. Acceleration/retardation may be determined based on a vehicle speed signal, through for example derivation of the speed signal, based on information from celerometer, based on positioning information, based on information regarding requested engine torque, or based on other suitable information from which acceleration/retardation may be determined.

Also other types of driving of the vehicle may impact on measurements of liquid levels in the vehicle's liquid

containers. For example, driving where the vehicle maintains a speed v exceeding- a threshold speed threshoia while the vehicle has a steering c exceeding a threshold for steering Cthreshoid may impact the measurement. Therefore, according to the embodiment the reliability for the measurement may be

determined, based on the speed v and the steering c.

According to one embodiment of the invention, at least one control device 150 in the mobile device, for example in a vehicle 100, comprises information about the degree/extent to which the various respective ambient factors impact the measurement of liquid levels in the containers in the device . This information may comprise a placement of at. least one measuring point in the respective containers and/or a geometry for the respective containers and/or a function induced movement within the respective containers.

As mentioned above, the container's geometry and/or the measuring point's position in the container may influence how great an impact acce1erations , retardat io s , speeds exceeding the threshold speed v_tbresboid jointly with steering- exceeding the threshold value Cthreshoid road gradients and other ambient factors nave on the measuring values for the liquid level. This is exemplified schematically in Figure 3, where a liquid container 300 is exposed to an ambient factor in the form of a road gradient in the travelling direction, which means that the liquid's surface 301 slopes in relation to the container, since the container obtains a gradient angle corresponding to the road gradient, i relation to the horizontal surface 301. This means that the measuring point's placement has a great impact on the measuring result. As illustrated in the figure, the ambient factor road gradient a impacts the measuring value considerably for the measurement points 302 , 303 at the container's ends in the travelling direction, while the measurement value is impacted less at a measuring point in the containers middle. The measurement points' placement across the travelling direction impacts, similarly, the measuring values if the road gradient a' s direction is across the travelling direction.

The container's geometry may in a similar manner influence the ambient factors' impact on the measuring values, since the design of the volume within the container may counteract or contribute to the ambient factors' impact, on the liquid surface, and thus on the liquid level, in the container. In addition, the container's geometry may, in interaction with the placement of the measuring point, influence the ambient factors' impact on the measuring values.

The function induced movement within the respective container about which the at least one control device 150 has

information, may for example consist of i formation about how rotating parts inside the engine 101, or rotating cogwheels ana shafts within the gearbox 103 impact the measurement of liquid levels in the containers in the device, for example in connection with measurement of engine and/or gearbox oil.

When prior art. solutions to the prese t problem were produced, consid.era.ble efforts and considerable manufacturing costs were invested in optimising precisely geometries and/or placements of measuring points in containers, in order to minimise the influence of the ambient factors' impact. With the use of the present invention this problem may instead be handled by control devices/control systems in the mobile device, which is a considerably less costly solution to the problem.

According to one embodiment of the present invention, the determination of the impact which the at least one ambient factor has on the measuring values for the liquid level is based on a second measurement, of at least, one second liquid level in at least one second container for liquids, arranged in the mobile device.

Here, the determination of the ambient factors' impact on the measuring values may comprise an analysis of whether or not the values for the first measurements of the first liquid level in the first container, and the values for the second measurements of the at least one other liquid level in the at least one other container, are changed substantially

uniformly. For example, the first measuring values which are obtained in a first, container, such as a fuel tank, may be compared to other measuring values obtained in at least one other container, such as a washer liquid container. If the first measuring values for the first container and the other measuring values for the at least one other container change in a manner which in some respect is similar, for example if the measuring values for both containers are impacted by a road gradient such as illustrated in figure 3, the analysis may result in the measuring- values changing- in a substantially uniform manner. If a uniform, change for several liquid

containers may be determined, the conclusion may be drawn that the ambient factors impact the measuring values, since the ambient factors should impact all the containers in the mobile device. Thus, it may be determined that, the first measurement of the liquid level in the first container, and also the other measurements in the respective at least one other container. are not reliable, since they are impacted by at least, one ambient factor.

If instea.d. it may be determined that, there is no uniform change for several liquid containers, the conclusion may be drawn that the ambient factors do not impact the measuring

^'values, since the ambient factors should have impacted, all the containers in the mobile device. Hence, the measuring values should then be reliable.

According to one embodiment, the substantially uniform, change comprises reactions which are substantially synchronous in respect of timing, that is to say that changes for the

measuring values in the different containers occur

substantially simultaneously. According to one embodiment, the substantially uniform change comprises similar changes in terms of size, that is to say that changes in the measuring- values occur which are substantially the same size in the different containers, where these changes do not. have to be synchronous in terms of timing. The substantially uniform change may also comprise combinations of synchronous reactions in terms of timing and similar changes in terms of size.

According to one embodiment of the invention, the first measurement of the first liquid level is deemed unreliable if the at least one ambient factor has had a. substantial impact, on said first measurement. Substantial impact, may here for example mean that the at least one ambient factor means that the measuring value differs by 5-20%, and according to one embodiment by at least 10%, from an actual value for the liquid, level.

When the control device/control system has determined whether the first measurement, of the liquid level is reliable or not, a value for the liquid level is determined according to one embodiment. The value for the liquid level is here determined based on the determined reliability for the first measurement.

The value for the liquid level may for example be determined through averaging, which according to one embodiment of the invention is adapted, based on the impact which the at least one ambient factor is deemed to have on the first measurement.

This adjustment of the averaging may comprise an adaptation of a number of measuring- values which are included in the

averaging. Here, fewer measuring values are then included if the first measurements are deemed reliable, so that the value for the liquid level may be determined faster when the

measurements are reliable. Through this adaptation, fast changes may thus be tracked if reliable measuring values are available. Similarly, more measuring values are included in the averaging if the first measurement is deemed unreliable.

The averaging may also be adapted through the use of weighting- factors at the averaging, so that measuring values which are deemed reliable are given a higher weight than the measuring values which are deemed to be unreliable. Hence, the speed and/or precision of the averaging, and thus of the de ermination of the value for the liquid level, may be adapted based on the determined reliability of the measuring values, which is advantageous.

According to another embodiment, the measurement, is ignored if the first measurement of the first liquid level is deemed to be unreliable. Hence, this avoids a situation where erroneous decisions are taken based on unreliable measuring values for 1 xquid levels .

According to one embodiment of the invention, one or several of a control device and a control system are arranged to decline from carrying out. a measure if the measurement of the liquid level is deemed unreliable. Here, the control

device/control system thus declines to carry out a measure which would have been carried out if the measurement had been deemed, reliable. Thus, the control device/control system's action is connected with the determined reliability of the measurements, which means that the occurrence of faulty measures, which are based on inaccurate data, is reduced,

A person skilled in the art will realise that the method for level measurement of liquids in a mobile device, such as for example a. vehicle, an aeroplane or a ship, according to the present invention, may also be implemented in a computer program, which when executed in a computer will cause the computer to carry out the method. The computer program usually consists of a part, of a computer program product 403, where the computer program product comprises a suitable digital storage medium on which the computer program is stored. Said computer readable medium consists of a suitable memory, e.g.: ROM (Read-Only Memory) , PROM (Programmable Read-Only Memory} , EPROM (Erasable PROM) , Flash, EEPROM. (Electrically Erasable PROM), a hard disk device, etc.

Figure 4 schematically shows a control device 400. The control device 400 comprises a calculation device 401, which may consist of essentially a suitable type of processor or

microcomputer, e.g. a. circuit for digital signal processing (Digital Signal Processor, DSP) , or a circuit, with a

predetermined specific function (Application Specific

Integrated Circuit, ASIC) . The calculation device 401 is connected to a memory unit 402 installed, in the control device 400, providing the calculation device 401 with e.g. the stored program code and/or the stored data which the calculation device 401 needs in order to be able to carry out calculations. he calculation device 401 is also set up to store interim or final results of calculations in the memory device 402.

Further, the control device 400 is equipped with devices 411, 412, 413, 414 for receiving and sending of input and output signals, respectively. These input and output signals may contain wave shapes, pulses, or other attributes, which may be detected as information by the devices 411, 413 for the receipt of input signal's and may be converted into signals that may be processed by the calculation device 401. These signals are then provided to the calculation device 401. The devices 412, 414 for sending output signals are arranged to convert the calculation result from the calculation unit 401 into output signals for transfer to other parts of the

vehicle's control system., and/or the component (s) for which the signals are intended.

Each one of the connections to the devices for receiving and sending of input and output signals may consist of one or several of a cable; a data bus, such as a CAN (Controller Area Network) bus, a MOST (Media Oriented Systems Transport) bus, or any other bus configuration; or of a wireless connection.

A person skilled in the art will realise that the above- mentioned computer may consist of the calculation device 401, and that the above-mentioned memory may consist of the memory device 402.

Generally, control systems in modern vehicles consist of a communications bus system, consisting of one or several communications buses to connect a number of electronic control devices (ECUs) , or controllers, and different components localised on the vehicle. Such a control system may comprise a large number of control devices, and the responsibility for a specific function may be distributed among more than one control device. Vehicles of the type shown thus often comprise significantly more control devices than what is shown in

Figure 4, which is well known to a person skilled in the art within the technology area.

The present invention, in the embodiment displayed, is implemented in the control device 400. The invention may, however, also be implemented wholly or partly in one or several other control devices already existing in the vehicle or in a control device dedicated to the present invention.

According to one aspect, of the present invention, a system, is provided which is arranged for level measurement of liquids in a mobile device, such as for example a vehicle or a vessel. The system comprises a measuring device, which is arranged for a first mea.surem.ent of at. least one first liquid level in a first container for liquids, arranged in the mobile device. The first container may here for example be represented by one of the engine 101, the gearbox 103, the fuel tank 130, the reducing agent tank 121 or the additional container 140, which are all displayed schematically in figure 1.

The system according to the invention also comprises a first dete.rmina.tion device 151, which may be comprised in the control device 150, and which is arranged to determine an impact which at least one ambient factor may ave on the first measurement of the liquid level. As described above, the at least one ambient factor may impact the mobile device in such a manner that the measuring values are impacted.

The system also comprises a second determination device 152, which may be comprised in the control device 150, and is arranged to determine whether the level measurement is reliable. The determination of the measuring value's reliability is based, according to the invention, on the impact which the at least one ambient factor has had on the level measurement ' s measuring values.

The system according to the invention has the advantages described above regarding the method according to the

invention, and may also be arranged to carry out all the method steps in the embodiments of the invention described above and in the claims.

A person skilled in the art. will also realise that the above system may be modified according to the different embodiments of the method according to the invention. In addition, the invention pertains to a motor vehicle 100, for example a truck or a bus, or a vessel, such as an aeroplane or a ship, comprising at least one system for level measurement of liquids according to the invention.

The present invention is not limited to the embodiments of the invention described above, but pertains to and comprises all embodiments within the protected scope of the enclosed

independent claims.

Claims

1. Method for level measurement of liquids in a mobile device (100); characterised hy

- first measurement of at least one first liquid level in a first container (101, 103, 130, 121, 140) for liquids arranged in said mobile device (100);

- det.ermina.tion of an impact which at. least one ambient factor may have on said first measurement, wherein said at least one ambient factor impacts said mobile device (100);

- determination of whether said first measurement is reliable, wherein said determination is based on said determined impact by said at least one ambient factor.

2. Method according to claim 1, wherein said

determina ion of said impact by said at least one ambient factor is based on a gradient a for said mobile device (100) .

3. Method according to claim 2, wherein said gradient . constitutes one or several from the group of:

- a road gradient a along a vehicle's (100) travelling

directi on; and

- a road gradie t a across a vehic1e ' s ( 100) trave11ing direction .

4. Method according to any one of claims 2-3, wherein said road gradient is determined in said vehicle (100) and/or determined based on information provided by another vehicle ,

5. Method according to any one of claims 2-3, wherein said road gradient a is determined based on topographical map data .

6. Method according to any one of claims 2-5, wherein said road gradient is determined based on positioning information .

7. Method according to any one of claims 1-6, wherein said mobile device is a vehicle (100) and wherein said

determination of said impact from said at least one ambient factor is based driving of said. vehic1e ( 100 } .

8. Method according to claim 7, wherein said driving- of said vehicle (100) comprises one or several of:

- an acceleration of said vehicle (100);

- a retardation of said vehicle (100); and

- a speed v exceeding a threshold speed v_thres_hoi_d an a steering c exceeding a threshold for steering c_thres_hoid /

9. Method according to any one of claims 1-8, wherein said determination of said impact by said at least one ambient factor is based on a second measurement of at least one other liquid level in at least one other container (101, 103, 130, 121, 140) for liquids, arranged in said mobile device.

10. Method according to claim 9, wherein said

determination of said impact by said at least one ambient factor comprises an analysis of whether the values for said first measurement, of said at least one first liquid level in said first container (101, 103, 130, 121, 140), and of said at least one other liquid level in said at least one other container (101, 103, 130, 121, 140), change substantially uniformly .

11. Method according to claim 10, wherein said

substantially uniform change comprises one or several of:

- reactions which are substantially synchronous in terms of timing; and

- changes which are similar in terms of size.

12. Method according to any one of claims 1-11, wherein a value for said first liquid level is determined based on said first measurement, and on said determination of whether said first measurement is re 1iab1e .

13. Method according to any one of claims 1-12, wherein an averaging of values for said first liquid level is adapted, based on said impact which said at least one ambient factor may have on said first measurement.

14. Method according to claim 13, wherein said adaptation comprises one or several of:

- an adaptation of a number of measuring values which are included in the averaging-, wherein said number is reduced when said first measurement is deemed reliable;

- an adaptation of a number of measuring values which are included in the averaging, wherein said number increases when said first measurement is deemed unreliable;

- an adaptation of one or several weighting factors at the averaging, where measuring values which are deemed reliable are given a higher weighting than measuring values which are deemed unreliable.

15. Method according to any one of claims 1-14, wherein said first measurement of said first liquid level is deemed unreliable if said at least one ambient factor has had a substantial impact on said first measurement,

16. Method according to claim 15, wherein said first measurement is ignored if said first measurement of said first liquid level is deemed unreliable.

17. Method according to claim 15, wherein, if said first measurement of said first liquid level is deemed unreliable, at least one control device (150) in said mobile device (100) declines to carry out a measure, which the at least one control device (150} would have carried out. if said first measurement had been deemed reliable,

18. Method according to any one of claims 1-17, wherein at least one control device (150) in said mobile device (100) comprises information about to what level the respective at least one ambient factor impacts said first measurement of at least one first, liquid level in said first container (101, 103, 130, 121, 140) .

19. Method according to c1a im 18, wherein said

information comprises one or several of:

- a placement of at least one measuring point (302, 303, 304) in said at least one first, container (101, 103, 130, 121, 140);

- a geometry for said at least one first container (101, 103, 130, 121, 140); and

- a function induced movement within said at least one first container (101, 103, 140).

20. Computer program comprising a program code which, when said program code is executed in a computer, achieves that said computer carries out. the method according to any one of claims 1-1 .

21. Computer program product comprising a computer- readable medium and a computer program according to claim 20, said computer program being comprised in said computer- readable mediu .

22. System arranged for level measurement, of liquids in a mobile device (100); characterised by

- a measuring device (302, 303, 304), arranged for a first measurement of at least one first liquid level in a first container (101, 103, 130, 121, 140) for liquids arranged in said mobile device (100);

- a fist determination device (151), arranged for the

determination of an impact which at least one ambient factor may have o said first measurement, wherein said at least, one ambient factor impacts said mobile device (100);

- a second determination device (152), arranged for the determination of whether said first measurement is reliable, wherein said determination is based on said determi ation of said impact by said at least one ambient factor.