SE537396C2 - Procedure for detecting a blocked flow - Google Patents

Abstract

SUMMARY A method for detecting a river block (205) in a fluid system (201), which river block is arranged between a first fluid line (203) and a second fluid line connected to the first fluid line via the river block (205). The method includes controlling a flow head (202) connected to the first fluid conduit (203) so as to create at least one inflow (208) into the first fluid conduit (203) and controlling a metering unit (206) connected to the second fluid conduit (204). so that at least one effluent (209, 219) out of the second fluid line is created. The method comprises creating one of the said rivers (209) as a time-dependent flood of kand size and with a time constant T and remaining said at least one river (208, 219) as an Over time constant T substantially constant flow so that pressure fluctuations occur in at least one of said fluid lines (203, 204), to supply the amplitude of the pressure fluctuations and on the basis of the measured amplitude detect the river blockage (205).

Description

FIELD OF THE INVENTION The present invention relates to a method for detecting a blocked flock. The invention is particularly, but not exclusively, directed to the performance of such a method for detecting the degree of clogging of a filter in an SCR system for exhaust gas purification. The invention also relates to a computer program product comprising computer program code for implementing a method according to the invention, as well as an electronic control unit.

BACKGROUND ART In order to meet stringent requirements for exhaust gas purification, today's motor vehicles are usually equipped with a catalyst in the exhaust line to effect the catalytic conversion of environmentally hazardous constituents in the exhaust gases into less environmentally hazardous substances. A method used to achieve efficient catalytic conversion is based on injecting a reducing agent into the exhaust gases upstream of the catalyst. An reducing substance entering the reducing agent or formed by the reducing agent is forced by the exhaust gases into the catalyst where it is adsorbed on the active compounds in the catalyst, which gives rise to accumulation of the reducing agent in the catalyst. The accumulated reducing agent can either desorb, i.e. detach from the active compounds, or react with an exhaust gas to convert this exhaust gas to a non-hazardous substance. Such a reduction catalyst can, for example, be of the SCR type (SCR = Selective Catalytic Reduction). This type of catalyst is still referred to as the SCR catalyst. An SCR-1 catalyst selectively reduces NO in the exhaust gases but not the oxygen in the exhaust gases. In an SCR catalyst, a ureal ammonia-based reducing agent is usually injected, e.g. AdBlue, in the exhaust gases upstream of the catalyst. During the injection of urea into the exhaust gases, ammonia is formed and it is this ammonia that constitutes the reducing substance that contributes to the catalytic conversion in the SCR catalyst.

SE1150862 and WO2011142708 describe SCR systems for injecting reducing agent into an exhaust system upstream of an SCR catalyst. This type of SCR system includes a tank that hails the reducing agent. The SCR system also has a pump which is arranged to pump up the reducing agent from the tank via a suction hose and supply it via a pressurized hose to a dosing unit which is arranged at an exhaust system of the vehicle, such as e.g. in the case of an exhaust pipe, the exhaust system has. The dosing unit is arranged to inject a required amount of reducing agent into the exhaust pipe upstream of the SCR catalyst according to drivers stored in a control unit of the vehicle. In order to more easily regulate the pressure at small or no dosage amounts, the system can also have a return hose which is arranged from a pressure side and has the system returned to the tank. According to this configuration, it is possible to cool the dosing unit by means of the reducing agent which, when cooled, flows from the tank via the pump and the dosing unit back to the tank. In this way an active cooling of the dosing unit is provided. The return flow from the dosing unit to the container is essentially constant. The SCR system also includes a filter for filtering the reducing agent before dosing by the dosing unit. This filter is arranged to protect the dosing unit from being blocked by particles, such as e.g. soil particles, dirt, etc. The filter can be a paper filter, but other types of filters are of course common.

A problem with such filters is that they can be easily clogged, leading to a river blockage so that the reducing agent cannot be dosed as intended. Such a river blockage must be detected and guarded, as otherwise NOx gas emissions will rise. In WO2011142708 this problem is solved by continuously feeding accumulated amount of liquid which is dosed via a dosing unit and from these feeds dispensing if the filter needs to be replaced. This procedure is based on the assumption that a certain amount of dosing reducing agent leads to a certain degree of clogging of the filter. In order to avoid filter changes in inconvenient and condensed exhaust gas purification, it is advisable to provide a method for detecting whether the filter is clogged.

One way of detecting a river blockage, for example in the form of a clogged filter, is to feed the pressure drop across the clogged or partially clogged filter. Knowing the flow through the filter can determine the size of the blockage. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for being able to detect a river block in a fluid system at an early stage by simple means without affect the normal functioning of the fluid system.

According to a first aspect of the invention, this object is achieved by a method for detecting a river block in a fluid system, which river block is arranged between a first fluid line and one connected to the first fluid line via the river block connected to another fluid line, the method comprising controlling a first fluid line flow head said that at least one inflow into the first fluid line is created and controlling a dosing unit connected to the second fluid line said that at least one outflow out of the second fluid line is created. The method further comprises creating one of said rivers as a time dependent flow of known size and with a time constant r and remaining said at least one river as a constant or substantially constant flow over time constant so that pressure fluctuations occur in at least one of said fluid lines, that feed the amplitude of the pressure fluctuations in one of said fluid lines where pressure fluctuations occur and on the basis of the measured amplitude detect the river blockage. Since the amplitude of the pressure fluctuations depends on the size of the river block, it is possible to detect whether there is a river block by feeding it. The absence of a flow blockage means less amplitude at the pressure fluctuations. The amplitude of the pressure fluctuations increases the larger the river blockage becomes, as the fluid conduits through the blockage are increasingly delimited from each other. With the method according to the invention, a river blockage can be detected at an early stage before it becomes critical and risks giving serious consequences. This is also done by only supplying the pressure in one of the fluid lines connected to the blockage. That is, with a pressure sensor, which reduces the need for hardware compared to the initially described kanda technology where a pressure drop is fed by the blockage. When the procedure is performed in e.g. moreover, an SCR system as initially described does not affect the normal operation of the system, since the process can be performed independently of constant or substantially constant flow to and from the two fluid lines, respectively, and since a time-dependent river head is already in place.

The river blockage can thus be detected at the same time as fluid flows as usual through the system.

According to one embodiment, the river block is detected on the basis of the measured amplitude, the size of the time-dependent flow and the volume V and elasticity E of the fluid system. Knowing these quantities results in a more accurate detection of the river block.

According to one embodiment, the measured amplitude is used as a test variable ti which is tested against an alarm criterion, and, given that the alarm criterion is met, an error code is generated. In this way, a control unit which is arranged to implement the method can automatically sound an alarm when the river blockage needs to be actuated. By directly using the measured amplitude, no calculations of the actual size of the river blockage need be performed by the control unit.

According to a further embodiment, the size of the river block is calculated on the basis of the measured amplitude, the size of the time-dependent flow, the volume Vi and elasticity of the first fluid line and the volume V2 and elasticity E of the second fluid line. , which is useful if the blockage only becomes critical as it exceeds a certain size.

You can then take action at the right time and avoid, for example, changing filters as the filter is only slightly clogged and the fluid system still works satisfactorily.

According to one embodiment, the calculated size is used as a test variable t1 which is tested against an alarm criterion, and, given that the alarm criterion is met, an error code is generated. In this way, a control unit which is arranged to implement the method can automatically sound an alarm when the river blockage needs to be actuated.

According to one embodiment, the alarm criterion is met if the test variable ti exceeds a predetermined threshold value. This is an easy way to determine if the river blockage needs to be remedied. Regardless of whether the calculated magnitude of the river blockage or the measured amplitude of the pressure fluctuations is used as test variable t1, the threshold value can advantageously be set so that it is optimized for the current fluid system, i.e. with respect to e.g. the fluid volumes' input volumes, elasticity, fluid properties, environmental parameters such as pressure and temperature, the size of the time-dependent river, etc.

According to a further embodiment, the method is carried out for a system in which the said fluid lines differ in volume. Preferably, the volume of one of said fluid conduits is at least ten times greater than the volume of another of said fluid conduits. The pressure fluctuations in such a system can become more marked in the smaller of the bath fluid lines, which facilitates the detection of the river blockage.

According to another embodiment, the time-dependent flow is created in the one of the said fluid lines which has the least volume. This usually gives the most marked pressure fluctuations.

According to a further embodiment, the amplitude of the pressure fluctuations in the one of the said fluid lines which has the least volume is fed. According to another embodiment, the amplitude of the pressure fluctuations in the one of the named fluid lines where the time-dependent flow is created is fed. In these ways, it is easiest to detect the pressure fluctuations because they usually become clearest in these cases. Of course, the one of the said fluid lines having the least volume may coincide with that of the said fluid lines where the time-dependent flow is created.

According to another embodiment, at least one named inflow is created into the first fluid line by controlling a river head in the form of a pump so that fluid is pumped from a tank into the said first fluid line. By using a pump, the said inflow can be created either as a time-dependent or as a constant or substantially constant flow.

According to a variant of this embodiment, fluid is returned from the second fluid line to said tank in a named outflow in the form of a return flow, and fluid is led out of the fluid system in a named outflow in the form of a consumption flow. In this way, a flow of fluid is created in the system, which is advantageous if the flake part of the fluid system is dependent on flow through to be cooled. For example, in a system for injecting reducing agent upstream of an SCR catalyst, a portion of the reducing agent is often used for dosing to the exhaust system via the effluent of the dosing unit and the portion of the reducing agent that is not dosed is returned in a return flow to the tank. This part of the reducing agent is advantageously used as a coolant to avoid overheating of the dosing unit. The reducing agent in the return flow is filtered and the SCR system therefore becomes to some extent self-cleaning. The required filtered reducing agent thus does not contribute to further clogging the filter.

According to one embodiment, the dosing unit is controlled to create the said time-dependent flow. This is advantageous in applications where it is desired that the fluid instead of through a continuous outflow should leave the fluid system in the form of discrete doses, as is often the case in a system for injecting reducing agents upstream of an SCR catalyst.

According to a further embodiment, the time-dependent flood 30 is created in the form of a time-periodic flood. Preferably, the 8 time periodic flood is created in the form of a square wave-like flood. Such a flood is easily achieved by, for example, opening and closing a valve, whereby a square wave-like flood with a certain time constant is created. Preferably the time periodic plane is created with a period time of 0.1-10 s, more preferably 0.2-5 s, even more preferably 0.25-1 s.

According to one embodiment, the method is carried out in a fluid system comprising a river blockage in the form of a filter which is somewhat clogged, the degree of clogging of the filter being detected.

According to another embodiment, the process is carried out for a system for injecting reducing agent, such as a urea or ammonia-based reducing agent, upstream of an SCR catalyst in an exhaust line from an internal combustion engine. The process is selectively designed for such a system because the system usually includes a time-dependent river head, such as a dosing unit which dispenses reducing agents in discrete doses to the exhaust line, and the clogging of a filter in such a system may need to be fed regardless of the substantially constant flow. is in the system. The method is further advantageous because no additional pressure sensor is needed but the river blockage can be detected with hardware existing in the system.

According to a further aspect of the invention, the object is achieved by a computer program downloadable to the internal memory of a computer, comprising software for controlling the steps according to the above-proposed method when said program is crossed on a computer.

According to another aspect of the invention, the object is achieved by a computer program product comprising a data storage medium which is readable by a computer, the computer program code of a computer program as above being stored on the data storage medium.

According to a further aspect of the invention, the object is achieved by an electronic control unit comprising an execution means, an execution means connected memory and one to the means of execution connected data storage medium, the computer program code of a computer program as above being stored on said data storage medium.

According to another aspect of the invention, the object is achieved by a motor vehicle comprising an electronic control unit as above.

Other advantageous features of the invention and advantages thereof are apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail below with the aid of exemplary embodiments with reference to the accompanying drawings, in which Fig. 1 shows a schematic sketch of a system in which the inventive method can be carried out, Fig. 2 shows a schematic sketch of a system for injection of reducing agent upstream of an SCR catalyst, and Fig. 3 shows a schematic sketch of a control unit for implementing a process according to the invention. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION By river block is meant a river block of some degree, i.e. also a partial block of a river. The partial block may be in a filter or located elsewhere in the fluid system, e.g. at a strangulation or the like.

Fluid system refers to a liquid or gas system. Preferably, but not necessarily, it is intended to have a system for flowing through a liquid. Preferably, but not necessarily, it refers to a fluid system in a vehicle. The fluid system can be, for example, a system for injecting reducing agent upstream of an SCR catalyst in an exhaust line from an internal combustion engine, a fuel system intended to supply an internal combustion engine with fuel, a hydraulic brake system in a vehicle, a hydraulic system, a pneumatic system, etc.

By fluid conduit is meant a passage for holding and transporting a fluid, such as e.g. a reductant in liquid form. The pipe can be a rudder of any dimension. The cable can consist of any, suitable material, such as e.g. plastic, rubber or metal !.

By dosing unit is meant a unit comprising a valve device of some kind, which can be controlled to create a constant or time-dependent flow of candle size. By a constant or substantially constant flow is meant a river which has a time constant which is considerably larger than the time constant of the time-dependent floc, so that the variations of the constant or substantially constant flow over time are much slower than the variations of the time-dependent river over time.

A first fluid system 101 in which the method according to the invention can be carried out is shown schematically in Fig. 1. The fluid system comprises a river skull in the form of a pressurized fluid container 102 with a volume VB, a first fluid line 103 with a first volume Vi, a second fluid line 104 with a second volume V2 and a river block 105 arranged between the first and the second fluid line. A dosing unit 106 is arranged in connection with the second fluid line, as well as a pressure sensor 107.

To calculate the magnitude of the river block 105, an inflow 108 is created into the first fluid line 103 from the pressurized container 102. Using the metering unit 106, a time-dependent effluent 109 of magnitude and with a time-constant T (i.e., the time it takes for the flood) is created. to increase / decrease to about 63% of its maximum level) from the second fluid line 104. Pressure fluctuations then occur in the fluid system 101. With the aid of the pressure sensor 107 the pressure in the second fluid line 104 is measured and the amplitude of the pressure fluctuations is determined. Since the amplitude of the pressure fluctuations is a function of the magnitude of the river block, a block can be detected, for example, by observing how the amplitude changes over time. The greater the river blockage, the greater the amplitude of the pressure fluctuations. With knowledge of the input system volumes VB, V1 and V2 and the elasticity Eg of the container 102 and the elasticity E1 and E2 of the fluid lines, respectively, as well as the size of the outflow, the size of the river block can be estimated. In the event that throttles of the same order of magnitude as or greater than the flow block 105 occur in the fluid system 101 between the pressurized container 102 and the first fluid conduit 103, the volume and elasticity of the container 102 may be disregarded.

In a fluid system similar to the system described above, instead of a pressurized container, a pump connected to a fluid tank can be used as a river head. The pump can be controlled to create a time-dependent inflow and the dosing unit can then be arranged to create a constant inflow, or an outflow which is substantially constant over the time constant T. The pressure sensor can be connected to either of the fluid lines, but suitably the fluid system is arranged so that the pressure feeder is connected to the one of the padded fluid lines which has the least volume, since the pressure fluctuations become most marked in this fluid line. Preferably, but not necessarily, this fluid line coincides with the fluid line where the time-dependent flow is created, which can lead to more marked pressure fluctuations.

A fluid system 201 for injecting reducing agent upstream of an SCR catalyst (not shown) in an exhaust line from an internal combustion engine is schematically illustrated in Fig. 2. The system comprises a flow head in the form of a pump 202 arranged to pump in reducing fluid from a fluid line 211. a tank 212 and into a fluid line 203. In direct connection to the fluid line 203 a main filter 205 is arranged and downstream there is a fluid line 204. Adjacent to this there is a 13 control unit (not shown) electrically controllable dosing unit 206, which is arranged to inject via a metering valve 210 into reducing agent in said exhaust line not shown. The dosing unit 206 comprises an electronic control card (not shown), which is arranged to handle communication with the control unit. The dosing unit 206 may also comprise plastic and / or rubber components, which may melt or otherwise be adversely affected at excessive temperatures. A pressure sensor 207 is arranged to supply the pressure in the second fluid line 204.

From the dosing unit 206 a return line 213 is arranged, which via a choke 214 leads back to the tank 212. In addition to the main filter 205, a number of filters 215, 216, 217 are arranged in the fluid system. The filter 217 in this case is considerably larger than the main filter 205.

In use, the pump 202 creates a substantially constant inflow 208 of reducing agent in the fluid line 203. The reducing agent is filtered at the main filter 205 and passes into the fluid line 204. Downstream of the fluid line 204, the reducing agent is dispensed to the exhaust line by the metering unit 206, which is controlled to create a discharge 209 of known size from the second fluid line 204 in the form of a square wave-like flow by opening and closing the metering valve 210. Via the metering unit 206, non-metered reducing agent is also led back to the tank 212 in a substantially constant return flow 219 via the restrictor 214. the dosing unit 206 can be continuously cooled with the aid of reducing agent. When the metering valve 210 is closed, a pressure is built up by the pump 202 in the fluid line 204 against the throttle 214 and when the metering valve 14 210 is open, the pressure is released because reducing agents then flow out through both the metering valve and through the throttle 214. the amplitude of the pressure fluctuations is calculated by the control unit and from this the degree of clogging of the main filter 205 can be determined. On the basis of the measured amplitude, the magnitude of the time-dependent flow, the volume Vi and elasticity E1 of the fluid line 203 and the volume V2 and elasticity E2 of the fluid line 204, the degree of clogging of the main filter 205 is calculated.

In this embodiment of the method according to the invention, the fluid system 201 is arranged with a first fluid line 203 whose volume Vi is about ten times larger than the volume V2 of the second fluid line 204. The time-dependent flow 209 is created in the form of a square wave in the second fluid line 204, at which also the pressure is fed. The pressure fluctuations are therefore easy to detect with the aid of the pressure sensor 207. The degree of clogging of the main filter 205 can be determined independently of the substantially constant inflows and outflows 208, 219 of reducing agents in the fluid lines 203, 204. The fact that the rivers are substantially constant meant that the time constant of the time-dependent, in this case square-wave, river 209 is considerably smaller than any time constants of the other rivers 208, 219. This may mean, for example, that the time constant T of the time-dependent river is in the order of one-tenth of a second, while the other rivers vary over a considerably longer time, as with a time constant in the interval 5-30 s.

The calculated size of the river block can suitably be used as a test variable in which, with the aid of the control unit, it is tested against an alarm criterion. Given that the alarm criterion is met, an error code is generated. The alarm criterion can, for example, be set so that it is met if the test variable ti exceeds a predetermined threshold value.

Instead of calculating the magnitude of the river block, it may be appropriate to use the measured amplitude of the pressure fluctuations as a test variable ti. In this case, the threshold value can be set so that the magnitude of the fluid system is taken into account, as well as the volumes and elasticity of the fluid lines so that an actual value of the size of the river block does not need to be calculated. Lampliga thresholds can e.g. determined empirically or by means of simulation. For some applications, however, the quantities of the fluid system may vary with, for example, temperature and pressure. In, for example, industrial systems, the pressure can vary between about 500-2000 bar and the elasticity of the system becomes highly dependent on the pressure. In these cases, it may be advantageous to either calculate the size of the river block and use it as a test variable ti or to use a threshold value which is e.g. pressure dependent.

Computer program code for implementing a method according to the invention is suitably included in a computer program which can be loaded into the internal memory has a computer, just as the internal memory has an electronic control unit has a motor vehicle. Such a computer program is suitably provided via a computer program product comprising a data storage medium which can be read by an electronic control unit, which data storage medium has the computer program stored there. Said data storage medium is, for example, an optical data storage medium in the form of a CD-ROM, a DVD-disc, etc., a magnetic data storage medium in the form of a hard disk, a floppy disk, a cassette tape, etc., or a flash memory or a memory of type ROM, PROM, EPROM or EEPROM.

Fig. 3 schematically illustrates an electronic control unit 40 comprising an execution means 41, such as a central processor unit (CPU), for executing computer software. The execution means 41 communicates with a memory 42, for example of the RAM type, via a data bus 43. The control unit 40 also comprises data storage medium 44, for example in the form of a Flash memory or a memory of the type ROM, PROM, EPROM or EEPROM. The execution means 41 communicates with the data storage medium 44 via the data bus 43. A computer program comprising computer program code for implementing a method according to the invention is stored on the data storage medium 44.

The invention is of course not limited in any way to the embodiments described above, but a number of possibilities for modifications thereof should be obvious to a person skilled in the art, without the latter deviating from the basic idea of the invention as defined in the appended claims. 17

Claims (21)

537 396 PATENT REQUIREMENTS A method of detecting a river block (105, 205) in a fluid system (101, 201), the river block being arranged between a first fluid conduit (103, 203) and a second fluid conduit connected to the first fluid conduit (105, 205). fluid conduit (104, 204), the method comprising controlling a river skull (102, 203) connected to the first fluid conduit (102, 202) so that at least one inflow (108, 208) into the first fluid conduit (103, 203) is created. and controlling a dosing unit (106, 206) connected to the second fluid line (204, 204) so that at least one outflow (109, 209, 219) out of the second fluid line is created, characterized in that the method comprises creating one of the said the rivers (109, 209) as a time-dependent flood of kand size and with a time constant T and the remaining said at least one river (108, 208, 219) as an Over time constant T constant or substantially constant flow so that pressure fluctuations occur in at least one of saidfluid lines (103, 104, 203, 204), to supply the amplitude of the pressure fluctuations in one of said fluid lines (104, 204) where pressure fluctuations occur and on the basis of the measured amplitude detect the river blockage (105, 205). Method according to claim 1, characterized in that the river block (105, 205) is detected on the basis of the measured amplitude, the magnitude of the time-dependent flow (109, 209) and the volume V and elasticity of the fluid system E. 18 537 396 Method according to claim 1 or 2, characterized in that the measured amplitude is used as a test variable ti which is tested against an alarm criterion, and that, given that the alarm criterion is met, an error code is generated. Method according to claim 1, characterized in that the size of the river block (105, 205) is calculated on the basis of the amplitude measured, the size of the time-dependent flow (109, 209), the volume V1 of the first fluid line and elasticity E1 and the volume V2 of the second fluid line. and elasticity E2. Method according to claim 4, characterized in that the calculated size is used as a test variable ti which is tested against an alarm criterion, and that, given that the alarm criterion is met, an error code is generated. Method according to claim 3 or 5, characterized in that the alarm criterion is met if the test variable ti exceeds a predetermined threshold value. A method according to any one of the preceding claims, characterized in that it is carried out for a system in which the said fluid lines (103, 104, 203, 204) differ in volume. A method according to claim 7, characterized in that it is performed for a system where the volume of one of said fluid conduits (203) is at least ten times larger than the volume of another of said fluid conduits (204). 19 537 396 A method according to claim 7 or 8, characterized in that the time-dependent flow is created in that of said fluid conduits (104, 204) having the least volume. Method according to any one of claims 7 to 9, characterized in that the amplitude of the pressure fluctuations is fed into the one of the said fluid lines (104, 204) which has the least volume. A method according to any one of the preceding claims, characterized in that the amplitude of the pressure fluctuations is fed into that of the said fluid lines (104, 204) where the time-dependent floc (109, 209) is created. A method according to any one of the preceding claims, characterized in that at least one narrow inflow (208) into the first fluid line (203) is created by controlling a river head in the form of a pump (202) so that fluid is pumped from a tank (212). ) into said first fluid conduit (203). A method according to claim 12, characterized in that fluid is returned from the second fluid line (204) to said tank (212) in a named outflow in the form of a return flow (219), and that fluid is led out of the fluid system (201). in a named outflow in the form of a consumption flood (209). A method according to any one of the preceding claims, characterized in that the dosing unit (106, 206) is controlled to create the said time-dependent flocculation (109, 209). 537 396 A method according to any one of the preceding claims, characterized in that the time-dependent flood (109, 209) is created in the form of a time-periodic flock. A method according to any one of the preceding claims, characterized in that it is performed for a fluid system comprising a river block (105, 205) in the form of a filter which is somewhat clogged, the degree of clogging of the filter (105, 205) being detected. Process according to any one of the preceding claims, characterized in that the process is carried out for a system (201) for injecting reducing agent upstream of an SCR catalyst in an exhaust line from an internal combustion engine. A computer program comprising computer program code for causing a computer to implement a method according to any of claims 1-17 when the computer program code is executed in the computer. A computer program product comprising a data storage medium 20 readable by a computer, wherein the computer program code of a computer program according to claim 18 is stored on the data storage medium. An electronic control unit (40) comprising an execution means (41), a memory (42) connected to the execution means and a data storage medium (44) connected to the execution means, the computer program code having a computer program according to claim 18 being stored on said data storage medium (44). Motor vehicle comprising an electronic control unit (40) according to claim 20. 21 1/1 101102 104 106 103 10109