WO2014035322A1

WO2014035322A1 - Method and system to establish a sensor function for a pm sensor

Info

Publication number: WO2014035322A1
Application number: PCT/SE2013/051004
Authority: WO
Inventors: Ola Stenlåås
Original assignee: Scania Cv Ab
Priority date: 2012-08-30
Filing date: 2013-08-28
Publication date: 2014-03-06
Also published as: DE112013003836B4; DE112013003836T5

Abstract

The present invention pertains to a method to establish a sensor function for a PM sensor intended for the determination of a particle content in an exhaust stream resulting from combustion in a combustion engine (101), where an aftertreatment system (200) is installed for aftertreatment of the said exhaust stream. The method comprises: - establishing a representation of an initial concentration in the said PM sensor and/or fraction of an initial substance (Si) in the said exhaust stream with the use of the elements set up in the said PM sensor for the determination of a representation of a concentration and/or fraction of the said initial substance (Si), and - based on the said esetablished representation of a concentration and/or fraction of the said first substance (Si), confirming whether the said PM sensor emits a signal which is representative of the said exhaust stream. The invention also relates to a system and a vehicle.

Description

Method and system to establish a sensor function for a PM sensor

Field of the invention

The present invention pertains to a system for the treatment of exhaust streams resulting from a combustion process, and in particular to a method by which a sensor function for a PM sensor is confirmed according to the preamble of patent claim 1. The invention also relates to a system and a vehicle, as well as a computer program and a computer program product, which implement the method according to the invention.

Background of the invention

In connection with increased government interests concerning pollution and air quality, primarily in metropolitan areas, emission standards and regulations have been drafted in many jurisdictions .

Such emission regulations often consist of requirements which define acceptable limits for exhaust emissions in vehicles equipped with combustion engines. For example, levels of nitrogen oxides (NO_x) , hydrocarbons (HC) and carbon monoxide (CO) are often regulated. These emission regulations usually also pertain to, at least in relation to certain types of vehicles, the presence of particles in exhaust emissions.

In an effort to fulfil these emission regulations, the exhausts caused by the combustion of the combustion engine are treated (purified) . By way of example, a so-called catalytic purification process may be used, so that aftertreatment systems in e.g. vehicles and other vessels usually comprise one or more catalysts.

Further, such aftertreatment systems often comprise, as an alternative to or in combination with a single or several catalysts, other components. Aftertreatment systems in vehicles with diesel engines, for example, often comprise particulate filters.

The combustion of fuel in the engine combustion chamber (e.g. cylinders) forms soot particles. According to the above, there are emission regulations and standards also pertaining to these soot particles, and in order to comply with the

regulations, particulate filters may be used to catch soot particles. In such cases, the exhaust stream is led e.g.

through a filter structure where soot particles are caught from the exhaust stream passing through for storage in the particulate filter.

Thus, there are numerous methods to reduce emissions from a combustion engine. In addition to regulations pertaining to emission levels, legislative requirements regarding so-called OBD systems (On-Board Diagnostics) are increasingly common, ensuring that vehicles actually comply with regulatory requirements regarding emissions in their daily operation, and not just during e.g. visits to a garage.

In relation to particle emissions, this may be achieved e.g. with the help of a particle sensor installed in the exhaust system or the aftertreatment system, referred to below in the description and patent claim as a PM sensor (PM = Particulate Matter, Particulate Mass) , which measures the particle concentration in the exhaust stream. Particle concentration may be determined e.g. as a particle mass per volume or weight unit, or as a certain number of particles of a certain size per volume unit, and several determinations of the amount of particles of varying sizes may be used to determine particle emission.

Aftertreatment systems with particulate filters may be very efficient, and the resulting particle concentration after the passage of the exhaust stream through the aftertreatment system of the vehicle is often low with a fully functional aftertreatment system. This also means that the signals which the sensor emits will indicate a low or no particle emission.

Summary of the invention

One objective of the present invention is to provide a method to establish a sensor function for a PM sensor intended to determine a particle concentration in an exhaust stream resulting from combustion in a combustion engine. This objective is achieved with a method according to patent claim 1.

The present invention pertains to a method to establish a sensor function for a PM sensor intended for the determination of a particle content in an exhaust stream resulting from combustion in a combustion engine, where an aftertreatment system is installed for aftertreatment of the said exhaust stream. The method comprises:

- establishing a first representation of a concentration and/or a fraction of a first substance present in the said exhaust stream in the said PM sensor by using elements installed in the said PM sensor for the determination of a representation of a concentration and/or fraction of the said first substance, and

- based on the said established representation of a

concentration and/or fraction of the said first substance, determining whether the PM sensor emits a signal which is representative of the said exhaust stream.

As mentioned above, PM sensors may be used to ensure that the level of particles in the exhaust stream resulting from the combustion engine does not exceed stipulated levels.

In order to ensure that the presence of particles in the exhaust stream is below the stipulated level, the PM sensor must, however, emit a correct signal. A PM sensor may be set up at various points in the exhaust stream, and depending on its position, a PM sensor may be set up so that the presence of particles at the location of the PM sensor is very small. This applies e.g. to a PM sensor which is set up downstream from a particulate filter, where a correctly functioning particulate filter is often capable of separating a very significant part of the particles emitted from the combustion engine's combustion chamber.

This in turn means that it may be difficult to differentiate a situation where the particulate filter is functioning

correctly, but where the concentration of particles downstream from the particulate filter is very low, from a situation where the PM sensor indicates a low concentration because of actual malfunction of the PM sensor or lack of a

representative signal for another reason.

There may be several reasons why a PM sensor does not emit a representative signal, i.e. not only a malfunction of the PM sensor causing a lower concentration than what is actually the case. However, the PM sensor may as such emit a signal representative of the environment in which the PM sensor is located, where the PM sensor and/or the aftertreatment system have been manipulated so that the sensor no longer measures particle concentration in a representative exhaust stream.

For example, the sensor may have been moved from the intended position in the exhaust stream to e.g. a position where it measures particle concentration in the vehicle's surroundings. In such cases, the PM sensor will always emit a signal representing a very low or no particle concentration

regardless of the actual particle concentration of the exhaust stream. Another way of manipulating the signal emitted by the PM sensor in order to reduce the detected particle concentration is to divert all or part of the exhaust stream past the PM sensor, so that the latter is no longer exposed to a

representative exhaust stream. In this manner, the PM sensor may also be induced to emit signals representing a lower particle concentration than what is actually the case. Another way of manipulating the sensor signal is by blocking the sensor so that the exhaust stream is not led through the sensor .

Thus, there are numerous ways of manipulating a PM sensor, and since the PM sensor as per the above may be placed in such a way that only a very small particle concentration is detected, it may be very difficult to determine whether or not the sensor has been manipulated.

According to the present invention, a method is provided in order to determine whether the PM sensor may be assumed to emit a representative signal, and to determine whether the sensor is faulty or if it has been manipulated.

According to the present invention, this is achieved with the use of elements installed by the PM sensor for the

determination of a representation of a concentration and/or fraction of a substance occurring in the exhaust stream. These elements may e.g. consist of a concentration/fraction sensor, which measures the concentration/fraction for some substance other than particles in the exhaust stream, and which is integrated with the PM sensor, i.e. it uses joint components as substrate or similar, or constitute a separate

concentration/fraction sensor, incorporated into a joint housing with the PM sensor. The concentration/fraction sensor may e.g. consist of a gas concentration sensor, where the said first substance is a gas, but also, according to one embodiment, of a PM sensor where the concentration of particles is established, and where the PM sensor may consist of an electrostatic or resistive PM sensor .

The concentration/fraction sensor may consist of a sensor of electrochemical type, or of a sensor of semiconductor type, such as a silicon carbide-based sensor.

By thus establishing a representation of the

concentration/fraction for any substance occurring in the exhaust stream, this concentration/ fraction may be compared with a representation of an expected concentration/fraction, and based on this comparison, it may be established whether the PM sensor may be deemed to be exposed to a representative exhaust stream, i.e. an exhaust stream which correctly reflects the composition in the exhaust stream which leaves the combustion chamber of the combustion engine.

Further characteristics of the present invention and

advantages thereof will be described in the detailed

description of example embodiments set out below and the enclosed drawings.

Brief description of drawings

Fig. la shows a diagram of a vehicle in which the present invention may be used.

Fig. lb shows a control device in the control system for the vehicle in Fig. 1.

Fig. 2 shows the aftertreatment system in more detail for the vehicle in Fig. 1.

Fig. 3 shows an example embodiment according to the present invention . Fig. 4 shows an alternative example embodiment according to the present invention.

Detailed description of embodiments

The expression particle concentration comprises, in the description below and the subsequent patent claim,

concentration in the form of mass per unit and concentration as number of particles per unit. Further, the unit may be comprised of any applicable unit and the concentration may be expressed as, for example, mass or number of particles per volume unit, per mass unit, per time unit, per work completed, or per distance travelled by the vehicle.

Fig. 1A shows a diagram of a driveline in a vehicle 100 according to an embodiment of the present invention. The vehicle 100 shown in Fig. 1A comprises only one shaft with wheels 113, 114, but the invention is applicable also to vehicles where more than one shaft is equipped with wheels, and vehicles with one or more shafts, such as one or more support shafts. The driveline comprises one combustion engine 101, which in a customary manner, via an output shaft on the combustion engine 101, usually via a flywheel 102, is

connected to a gearbox 103 via a clutch 106.

The combustion engine 101 is controlled by the engine's control system via a control device 115. Likewise, the clutch 106, which may consist of e.g. an automatically controlled clutch, as well as the gearbox 103 are controlled by the vehicle's control system with the help of one or more

applicable control devices (not shown) . Naturally, the vehicle's driveline may also be of another type such as a type with a conventional automatic gearbox, etc.

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

The vehicle 100 also comprises an exhaust system with an aftertreatment system 200 for treatment (purification) of exhaust emissions resulting from combustion in the combustion chamber (e.g. cylinders) of the combustion engine 101.

One example of an aftertreatment system 200 is displayed in more detail in Fig. 2. The figure shows the combustion engine 101 of the vehicle 100, where the exhaust generated by the combustion (the exhaust stream) is led via a turbocharger 220. In turbo engines, the exhaust stream resulting from the combustion often drives a turbocharger which in turn

compresses the incoming air to the cylinders' combustion.

Alternatively, the turbocharger may e.g. be of compound type. The function of various types of turbochargers is well-known, and is therefore not described in any detail herein. The exhaust stream is subsequently led via a pipe 204 (indicated with arrows) to a diesel particulate filter (DPF) 202 via a diesel oxidation catalyst (DOC) 205.

The DOC 205 has several functions, and is normally used primarily in the aftertreatment to oxidise remaining

hydrocarbons and carbon monoxide in the exhaust stream into carbon dioxide and water. During the oxidation of hydrocarbons heat is also formed, which may be used to increase the particulate filter's temperature when e.g. the particulate filter is emptied (regenerated) .

The oxidation catalyst 205 may also oxidise nitric oxide (NO) to nitrogen dioxide (N0₂) , which is used for e.g. N0₂-based regeneration. Further reactions may occur in an oxidation catalyst.

Additionally, the aftertreatment system may comprise more components than indicated in the examples above, or fewer components. For example, the aftertreatment system may, as in the present example, comprise a SCR (Selective Catalytic

Reduction) catalyst 201 downstream of the particulate filter 202. SCR catalysts use ammoniac (NH₃) , or a composition from which ammoniac may be generated/formed, as an additive to reduce the amount of nitrogen oxides NO_x in the exhaust stream. According to one embodiment of the present invention, a concentration/fraction sensor is used to confirm the presence of ammoniac in the exhaust stream.

In the embodiment shown, the components DOC 205, DPF 202 and the SCR catalyst 201 are integrated into one and the same exhaust purification unit 203. However, it should be

understood that these components need not be integrated into one and the same exhaust purification unit, but the components may be arranged in another manner, where suitable, and one or several of the said components may e.g. consist of separate units. Fig. 2 also shows temperature sensors 210-212 and a differential pressure sensor 209. The figure also shows a PM sensor 213, whose function is determined according to the present invention, and which is shown downstream of the exhaust purification unit 203 in the present example. However, the PM sensor may also be set up upstream of the exhaust purification unit 203, as well as upstream of the turbocharger 220. Additionally, the vehicle's exhaust system may comprise more than one PM sensor, which may be set up at various positions, and by virtue of which the functionality of all the PM sensors in the vehicle may be assessed. The PM sensor 213 is, in the present invention, integrated or collocated with a concentration/fraction sensor 214, where the

concentration/fraction sensor 214 is adapted to determine the concentration of some applicable substance normally occurring in the exhaust stream. As mentioned above, soot particles are formed during the combustion of the combustion engine 101, and these soot particles may in many cases not be emitted into the

environment surrounding the vehicle. The soot particles are caught by the particulate filter 202, which functions so that the exhaust stream is led through a filter structure where soot particles are caught from the passing exhaust stream and subsequently stored in the particulate filter 202. With the help of the particulate filter 202, a very large part of the particles may be separated from the exhaust stream.

The PM sensor 213 may be used to control that the particulate filter 202 functions in the desired manner, but also to monitor e.g. the functionality of the combustion engine 101 in the event of e.g. a PM sensor position upstream from the particulate filter. The PM sensor 213 may also be used for other purposes.

However, in order for the particle occurrence determined with the help of PM sensor signals to be representative, the PM sensor 213 must emit signals which are representative of the environment in which the PM sensor is intended to be

installed.

The present invention improves the reliability of the PM sensor signals by assessing the environment surrounding the PM sensor. Fig. 3 shows an example embodiment 300, according to the present invention, with the help of which the PM sensor's environment, such as the exhaust stream surrounding the PM sensor may be evaluated and incorrect sensor signals depending on non-representative exhaust streams may be detected. The method is carried out according to the present example of the control device 208 shown in Fig. 1A-B and Fig. 2.

In general, control systems in modern vehicles consist of a communication bus system consisting of one or more communications buses to connect a number of electronic control devices (ECUs) , such as the control devices, or controllers, 115, 208, and various components arranged 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.

For the sake of simplicity, Fig. 1A-B shows only the control devices 115, 208.

The present invention is thus in the embodiment displayed implemented in the control device 208, which in the embodiment displayed may be in charge of other functions as well in the aftertreatment system 200, such as regeneration (emptying) of the particulate filter 202, but the invention may thus also be implemented in a control device dedicated to the present invention, or wholly or partly in one or more other control devices already existing in the vehicle, such as the engine control device 115.

The function according to the present invention of the control device 208 (or the control device (s) in which the present invention is implemented) will, in addition to depending on sensor signals from a sensor 210 for determination of a concentration and/or fraction of a substance, likely depend on e.g. information which e.g. is received from a PM sensor and e.g. the control device (s) which control the engine's

function, i.e. in the present example the control device 115.

Control devices of the type displayed are normally arranged to receive sensor signals from different parts of the vehicle. The control device 208 may e.g. receive sensor signals as per the above, and from other control devices than the control device 115. Such control devices are usually also set up to emit control signals to different parts and components of the vehicle. For example, the control device 208 may emit signals to e.g. the engine control device 115.

Control is often controlled by programmed instructions. These programmed instructions typically consist of a computer program, which, when it is executed in a computer or control device, causes the computer/control device to carry out the desired steering, as a method step in the process according to the present invention.

The computer program usually consists of a computer program product, where the computer program product comprises an applicable storage medium 121 (see Fig. IB) with the computer program 109 stored on the said storage medium 121. The said digital storage medium 121 may e.g. consist of any from the following group: ROM (Read-Only Memory) , PROM (Programmable Read-Only Memory) , EPROM (Erasable PROM), Flash, EEPROM

(Electrically Erasable PROM), a hard disk unit, etc., and may be set up in or in combination with the control device, where the computer program is executed by the control device. By changing the computer program's instructions, the vehicle's behaviour may thus be adjusted in a specific situation.

An example control device (control device 208) is displayed in the diagram in Fig. IB, and the control device in turn may comprise a calculation unit 120, which may consist of e.g. a suitable type of processor or microcomputer, e.g. a circuit for digital signal processing (Digital Signal Processor, DSP) , or a circuit with a specific function (Application Specific Integrated Circuit, ASIC) . The calculation unit 120 is connected to a memory unit 121, which provides the calculation unit 120 with e.g. the stored program code 109 and/or the stored data which the calculation unit 120 needs in order to be able to carry out calculations. The calculation unit 120 is also set up to store interim or final results of calculations in the memory unit 121.

Further, the control device is equipped with devices 122, 123, 124, 125 for receipt and sending of input and output signals. These input and output signals may contain waveforms, pulses, or other attributes, which may be detected by the devices 122, 125 for the receipt of input signals that may be detected as information for processing of the calculation unit 120. The devices 123, 124 for sending output signals are arranged to convert the calculation result from the calculation unit 120 to 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 receipt and sending of input and output signals may consist of one or several cables; or data buses, 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.

According to the above, the reliability for PM sensor signals may, according to the present invention, be increased by assessing the signal emitted by the PM sensor. Fig. 3 shows a first example embodiment 300, according to the present invention. The method begins at step 301, where it is

established whether the environment of the PM sensor 213 should be evaluated. If the environment of the PM sensor 213 is to be evaluated, the method continues to step 302. The transition from step 301 to step 302 may e.g. be arranged to be controlled by the time elapsed since a previous evaluation of the environment of the PM sensor 213. The environment of the PM sensor 213 may also be arranged to be evaluated continuously, with applicable intervals, every time the vehicle is started or at other applicable points in time. At step 302, a first concentration/fraction d is established for a first substance Si occurring in the exhaust stream. This concentration/fraction is established with the use of the said concentration/ fraction sensor 214, where the

concentration/fraction sensor 214 has been adapted to

establish the concentration/fraction of any applicable

substance normally occurring in the exhaust stream.

Below, it is assumed that the concentration/fraction sensor 214 consists of a gas concentration sensor 214 for the

determination of the concentration C of an applicable gas, and so this designation is used below for the sake of simplicity instead of a concentration/fraction sensor. Instead of

confirming a concentration, however, the sensor may be

arranged to confirm a fraction of any applicable substance, i.e. the substance's mole fraction (or weight fraction) in relation to total mole (or weight) for any applicable

composition, such as the entire exhaust stream, or in relation to any other substance occurring in the exhaust stream.

Generally, concentration and/or fraction may thus be used according to the present invention, and obviously the

description below applies equally to a gas fraction sensor as to a particle concentration or fraction sensor.

The gas concentration sensor 214 may e.g. be of a type which emits signals representing the concentration of a given substance, or signals with the help of which such

concentration may be calculated. The gas concentration sensor may e.g. consist of an oxygen (0₂) sensor, nitrogen oxide (NO) sensor, nitrogen dioxide (N0₂) sensor, hydrocarbon (HC) sensor, ammoniac (NH₃) sensor, or another applicable sensor intended to establish the concentration of any applicable substance in the exhaust stream. With respect to the example with ammoniac, this is applicable primarily in aftertreatment systems where a so-called SCR catalyst, according to the above, is used to reduce nitrogen oxides.

At step 302, a first concentration d is thus established for an applicable first substance Si . When the concentration Ci is thus established for the said first substance Si at step 302, the method continues to step 303, in which an expected concentration C_sxp for the said first substance Si is

established.

This expected concentration C_exp may e.g. be established by table lookup, where the expected concentrations C for the given substance Si may be specified for a number of different operational cases, such as e.g. different combinations of fuel injection times, fuel injection durations, fuel injection amounts, fuel pressure, number of injections), EGR and air supply, ventilation times, compression ratio, overcharging, VGT position, engine speed, combustion load, urea dosage, HC dosage, etc.

In order to ensure that as reliable values as possible are obtained for d and C_exp respectively, the transition from step 301 to step 302 may also be controlled so that it is carried out only in cases where the vehicle 100 has been operated in essentially continuous conditions for a certain duration, e.g. a number of seconds, in order to avoid that dynamic processes erroneously influence the measurement results. Subsequently, when the expected concentration C_sxp has been established at step 303, the method continues to step 304, where the concentration Cj for the first substance Si ,

determined with the use of the concentration sensor 214, is compared with the expected concentration C_sxp for the said first substance Si , and any discrepancy A between the expected concentration C_exp and the measured concentration d is established. At step 305, it is then established whether the discrepancy A between the expected concentration C_Sx_P and the measured concentration Ci is greater than any applicable limit Aiimi . The limit Ai_imi may e.g. be fixed in such a way that an applicably large discrepancy may be permitted in order to avoid giving rise unnecessarily to an alarm relating to the function of the PM sensor 213, since the composition of the exhaust stream may be difficult to predict with the desired accuracy. Provided this is not the case, the method continues to step

306, where the applicable signal may be generated to indicate that the PM sensor 213 may be assumed to emit representative values regarding the particle content in the exhaust stream, since the sensor may at least be assumed to carry out

measurements in a representative exhaust stream and thus to be located at the intended position in the exhaust stream. The method resumes to step 301 for a new determination of the PM sensor's function at the applicable time as per the above. Alternatively, the method may revert directly to step 301 from step 305 since no measure need actually be taken.

If on the other hand it is confirmed at step 305 that the discrepancy A is greater than the limit Ai_imi , the method continues to step 307. At step 307, an error signal is generated, e.g. an alarm signal, in order for the control system of the vehicle 100 to indicate that the PM sensor 213 may not be deemed to emit a representative signal, since it is not deemed to be subjected to a representative exhaust stream. The signal generated at step 307 may e.g. be used by the control system of the vehicle 100 in order to place the status of the vehicle 100 to a status where the vehicle 100 is in immediate need of service for action by the PM sensor 213. The control system may also be arranged to limit the functionality of the vehicle 100, e.g. by limiting the maximum output of the combustion engine 101 of the vehicle 100 until the fault is remedied. The method is then completed at step 308.

According to the present invention, a method is thus provided which may be used to confirm whether the PM sensor 213 emits a representative signal by confirming whether it is subjected to a representative exhaust stream. With the assistance of the present invention, attempts to manipulate the function of the PM sensor 213 may be identified during the operation of the vehicle 100, which thus reduces the potential for undetected manipulation of the aftertreatment system.

In the example in Fig. 3, a specific concentration Ci is compared to an expected concentration C_ex_P at a certain time. Obviously, the composition of emissions from a combustion engine 101 may vary significantly, and even if e.g. a table lookup or calculation according to the above is used to determine an expected concentration C_ex_P, an isolated value measured in unfavourable circumstances may differ from the expected value by more than the said discrepancy Ai_imi even though the PM sensor 213 is actually correctly installed in the exhaust stream. For this reason, the method shown in Fig. 3 may be set up to be completed an applicable number of times x, e.g. a relatively big number of times x, where x values are confirmed, and thus x discrepancies A, where an overall integrated discrepancy for these x discrepancies may be determined and compared with the discrepancy limit A_IM, and where the overall integrated value is used to confirm whether the PM sensor 213 may be assumed to be subjected to a

representative exhaust stream.

The discrepancy A_limi may also be set up to vary according to the number of measured values x. The greater the number of measured values x used, the lower the permitted discrepancy Aiimi may be set, since the overall integrated accuracy

increases with the number of measured values x.

In Fig. 4, another example embodiment 400 according to the present invention is shown, where the expected concentration C_sxp is established in an alternative manner.

The method 400 shown in Fig. 4 begins at step 401 where, just like at step 301 of Fig. 3, it is established whether the PM sensor's function should be determined. Where this is the case, the method continues to step 402, where a first

concentration Ci of the said first substance Si is confirmed with the use of the said concentration sensor 214 according to the above. The method then continues to step 403. Instead of, as in Fig. 3, establishing an expected concentration C_sx , the exhaust stream is actively impacted at step 403. This may be achieved e.g. by changing the operation of the combustion engine 101. The combustion engine's operation may e.g. be altered by changing the load or operating point for a given load. For example, the combustion engine's operating point may be changed by changing one or several of the fuel injection times, fuel injection durations, fuel injection amounts, fuel pressure, number of injections, EGR and air supply,

ventilation times, compression conditions, overload, VGT position, engine speed, combustion engine load, etc.

Alternatively, or additionally, the combustion mode at the said combustion engine may be switched, e.g. from Otto to HCCI or from Diesel to PPC. Alternatively, the load may be

increased by e.g. connecting inactive combustion engine-driven aggregates . By altering the manner in which the combustion engine 101 operates, or otherwise impacting the exhaust stream according to the above, the composition of the exhaust stream will also change. If e.g. the combustion engine 101 is induced to work harder, usually the oxygen level in the exhaust stream is reduced, i.e. the concentration of oxygen in the exhaust stream will be reduced. In the reverse, the occurrence of nitrogen oxides usually increases with an increased load. At step 403, the operation of the combustion engine 101 is thus changed in some applicable manner, and thus the composition of the exhaust stream changes. Preferably, a change resulting in a relatively large change in the exhaust stream's composition is carried out.

Instead of changing the operation of the combustion engine 101, the exhaust stream may instead, or in combination, be actively impacted at step 403 by bypassing one or several components in the aftertreatment system, or by connecting another component for the passage of at least part of the said exhaust stream, and thus the exhaust stream's composition is altered in this manner.

The exhaust stream may also be impacted by throttling the exhaust flow with a restrictor, such as an exhaust brake, where the said restrictor may e.g. be installed downstream of an intended position for the said PM sensor 213.

Additionally, the exhaust stream may be impacted by e.g.

adding hydrocarbon (fuel) or urea to the exhaust stream, which as such affects the exhaust stream, and additional impact may be obtained in the event of reactions in one or several of the aftertreatment system's components. The exhaust stream may also be arranged to be impacted upstream or downstream of a turbine, e.g. according to any of the examples above. The method then continues to step 404, where a second

concentration C₂ of the said first substance Si is confirmed, i.e. a concentration C∑ in the exhaust stream after the said one or several measures to alter the composition of the exhaust stream have been completed. At step 405, an expected change AC_exp is then established for the concentration of the said first substance Si after the measures taken at step 403, where the change AC_i2 at step 406 between the said first d and second values C∑ is compared to the expected change /\C_eKp for the concentration of the said first substance Si. In other words, according to this embodiment of the method shown in Fig. 4, no absolute concentrations need be established, instead it is sufficient to establish an expected change kC_exp, where such expected change AC may be established by way of calculation or table lookup based on the changes made

according to the above. At step 406 the actual change ΔΡ12 is then compared to the expected pressure change AP_exp in the manner described at step 304 in Fig. 3, and at step 407 it is established whether the discrepancy A is larger or smaller than any applicable discrepancy Ai_im2. If the discrepancy is below the limit An_m2, the method reverts to step 401 via step 408, which is

equivalent to step 306 above, while if the discrepancy A exceeds the limit Ai_im2, an error signal, such as an alarm signal, is generated at step 409 in a manner equivalent to step 307 in Fig. 3. The method is then completed at step 410. With the use of the method shown in Fig. 4, it may thus be confirmed not only that the PM sensor 213 is placed in an exhaust gas composition, but also that the PM sensor 213 is arranged inside an exhaust stream whose composition varies with varying operational conditions in a representative manner. This method may confirm that e.g. the PM sensor 213 has not been manipulated in such a manner that it has been placed in an isolated environment such as in an exhaust test tube and thus separated from the actual exhaust stream. As in the method shown in Fig. 3, the method shown in Fig. 4 may be arranged to be completed a number of times in order to determine a number of values by carrying out a number of changes in the composition of the exhaust stream. The method may also be arranged, and this also applies to the method shown in Fig. 3, to be completed over a certain time in order to verify that the expected changes actually occur over time.

Also, a combination of the methods shown in Fig. 3 and Fig. 4 are applied, i.e. a concentration change may be applied according to Fig. 4, but where at the same time the values before and after the change of the exhaust stream are compared with expected values before and after the change is confirmed, which may further improve accuracy.

In addition, the method may be carried out for more than one substance in the exhaust stream, and a sensor capable of carrying out concentration/fraction measurements for more than one substance separated from particles may be used.

Alternatively, two or more sensors for the respective

concentration/fraction measurements for respective substance separated from particles may be used, where more than one concentration sensor is integrated/collocated with the PM sensor. According to another embodiment, the

concentration/fraction measurements are carried out for particles and at least one further substance.

The present invention also has the advantage that, since the concentration of a substance occurring in the exhaust stream is confirmed, the determination according to the present invention may be carried out regardless of the PM sensor's position in the exhaust stream. Depending on the application, PM sensors may be arranged at different positions in the exhaust system. For example, the PM sensor may be installed upstream or downstream of an exhaust brake, as well as upstream or downstream of a particulate filter, or upstream of a turbocharger . Regardless of the placement, concentration changes in the exhaust stream will occur with changed

operational parameters.

Additionally, at least in certain cases, a frequency analysis may be used to confirm whether the PM sensor 213 emits a representative signal. Generally, the combustion engine's exhaust vents are opened with a specific regularity. For example, usually exhaust vents are opened once per revolution for two-stroke engines and once every other revolution for four-stroke engines.

This means that the exhaust stream is "pulsated" through the exhaust vents, and pulse-like differences will arise in the flow of the exhaust stream over time. This also means that the pulsation will give rise to variations in concentration at the same frequency for the substances occurring in the exhaust stream.

Normally, however, the balance between e.g. air supply, EGR feedback and fuel supplied is not exactly the same for each cylinder or for each consecutive combustion, e.g. because of tolerances, etc. In the time domain, these pulse/concentration variations in the exhaust stream will thus seem rather irregular .

If, on the other hand, the sensor signal from the

concentration sensor is instead evaluated in the frequency domain, this pulsation may be clarified and used according to the present invention.

The exhaust pulses from the different cylinders will be visible as concentration/fraction variations with a frequency which is equal to the combustion engine's speed multiplied by the number of cylinders and divided by the rate factor (i.e. divided by one for a two-stroke engine and divided by two for a four-stroke engine. There are also engines where the rate factor may be controllably varied) . In the frequency domain, a clear spike/peak will thus arise at the said frequency (weaker shadow pulses on multiples of the frequency may also arise) .

This frequency analysis may be used to improve safety in the diagnosis of the PM sensor, because if this pulsation may be identified, it may then also be assumed that the concentration sensor, and thus the PM sensor, is subjected to a

representative exhaust stream. The frequency analysis may be used alone or in combination with a comparison against a limit as per the above, where this limit may be set in the time domain or the frequency domain. By carrying out the

determination in the frequency domain, detection is possible with smaller variations, i.e. a lower Ai_lm limit may be used.

Variations in the frequency domain may also be used actively since the speed according to the method of the invention may be varied to give a more reliable diagnosis. If e.g. Ai_im is exceeded for one frequency (engine speed) , a pending error may be set, so that one or more further diagnoses for more frequencies may be carried out before the malfunction is finally confirmed.

Depending on which substance (s) occurring in the exhaust stream is/are analysed, the frequency analysis may also be arranged to be carried out in relation to the dosage of additives such as urea or fuel to the exhaust stream.

As explained above, the aftertreatment system may be of a type where additives are supplied in the exhaust stream to facilitate a reduction of one or several substances occurring in the exhaust stream.

For example, SCR catalysts usually use ammoniac (NH₃) or a composition from which ammonia may be generated/formed, such as urea, as an additive for the reduction of nitrogen oxides NO_x in the exhaust stream. This additive is injected into the exhaust stream resulting from the combustion engine upstream from the SCR catalyst and the additive added to the catalyst is adsorbed (stored) in the catalyst, so that nitrogen oxides in the exhausts react with the additive stored in the

catalyst .

This dosage of additives and fuel such as diesel in the exhaust stream is carried out often as injection pulses, typically at frequencies between e.g. 0.1 and 10 Hz. Thus, variations in these concentrations or in concentrations of substances dependent thereon (such as e.g. NO_x concentration after an SCR catalyst) will often vary with this frequency, so that a similar frequency analysis may be carried out also with respect to this.

It also happens that e.g. fuel is supplied to the exhaust stream as injection pulses, and a similar frequency analysis may be carried out in relation to the applicable substance in the pulsation caused by the fuel injection. Generally, with respect to frequency analysis, the result obtained from the analysis is more reliable the closer to the pulsation source the analysis is performed.

According to this embodiment, the said frequency analysis thus consists of a representation of a concentration and/or fraction of the given substance at the said PM sensor 213. There are also various types of PM sensors, and the present invention is applicable to all types of PM sensors. For example, there are so-called IDE sensors, where ceramic plates coated with conductive materials are used to confirm a particle content for a passing exhaust stream. As an exhaust stream containing particles passes the coated ceramic plates, particles will stick, which in turn entail that the

conductivity between two adjacent non-contacting plates will change. As particles (soot) stick on these plates, the conductivity increases, which entails that e.g. a resistance, current, voltage, conductivity or inductance, or the like, may be detected, and where changes in the relevant size indicate particle content. By determining a gradient of change over time, the particle content may be estimated by deciding how quickly e.g. a resistance, current or voltage, etc. changes. This type of particle sensor thus entails a relatively slow detection of particle content, and it may take a long time before the malfunction is discovered. According to the present invention, manipulation of this type of sensor may, however, be discovered at an early stage.

There are also other types of particle sensors, such as electrostatic particle sensors, where particles pass by a first electrode to pick up a charge and then pass a second electrode set up in the particle sensor where the charge is delivered. Depending on the particle content, the number of electrons per time unit which is transmitted between the electrodes will thus vary, and therefore both the particle content and also the particle number may be determined with immediate and very great accuracy.

According to one embodiment, this type of particle sensor is used to determine the concentration and/or fraction of particles in the exhaust stream. Thanks to the speed of the sensor, present value measurements may be made, i.e. values representing instantaneous particle content may be obtained. Thus, according to one embodiment, the said first substance may consist of particles, in which case concentration

determinations and concentration change determinations, respectively, according to the above, consist of particle content determinations and particle content change

determinations .

However, it has been noted that PM sensors may exhibit cross- sensitivity to substances supplied to the exhaust stream where additives are supplied, as above. For example, this cross- sensitivity may relate to water, urea, ammoniac or another added substance. This means that for at least some PM sensors the signal emitted, i.e. the signal which normally constitutes a representation of the occurrence of particles in the exhaust stream, will be affected by this cross-sensitivity. This cross-sensitivity entails that the PM sensor reacts to the presence of an additive in the exhaust stream and thus generates a signal which indicates a different concentration of particles than what is actually present.

This cross-sensitivity may thus lead to reduced accuracy in the diagnosis of PM sensors in systems where the PM sensor is placed downstream of the position where the additive is supplied, and where the PM sensor's signals are used in the diagnosis, as may be the case according to the above.

This realisation regarding cross-sensitivity may thus be used in the diagnosis of PM sensors, where dosage (addition) of additives according to one embodiment may be shut off during the diagnosis of the PM sensor, and more reliable measured values may be obtained compared to when the shutting off measure is not taken. Additionally, the method according to the invention may be combined with the method described in the Swedish application No. 1250961-8 entitled "METHOD AND SYSTEM PERTAINING TO

EXHAUST AFTERTREATMENT", by the same inventor and with the same submission date as the present application, in order to establish a sensor function for a PM sensor. According to the said application "METHOD AND SYSTEM PERTAINING TO EXHAUST AFTERTREATMENT", a method is provided, similar to the present invention, but where the sensor function for the PM sensor is established based on a representation of a pressure existing in the PM sensor, where the pressure is determined by a pressure sensor arranged in the PM sensor. This is achieved by using elements installed in the PM sensor to determine a representation of a pressure prevailing at the PM sensor.

These elements may e.g. consist of a pressure sensor

integrated with the PM sensor, i.e. the pressure sensor uses joint components such as substratum or similar. Alternatively, the pressure sensor may constitute a separate pressure sensor, but be installed in a common housing with the PM sensor.

By thus determining a prevailing pressure at the PM sensor, this pressure may be compared with an expected pressure, and based on the comparison, it may be determined whether the PM sensor may be deemed to be subject to a representative exhaust stream, i.e. an exhaust stream which correctly reflects the composition in the exhaust stream which leaves the combustion chamber of the combustion engine.

Also, the method according to the invention may, alternatively or additionally, be combined with that in the parallel Swedish application No. 1250964-2 entitled "METHOD AND SYSTEM

PERTAINING TO EXHAUST AFTERTREATMENT III", by the same inventor and with the same date of submission as the present application, described in order to establish a sensor function for a PM sensor. According to the said application "METHOD AND SYSTEM PERTAINING TO EXHAUST AFTERTREATMENT III", a method similar to the present method is provided, with the difference that the sensor function for the PM sensor is confirmed with the use of elements to confirm a representation of a

temperature at the PM sensor. This is achieved with the use of elements installed in the PM sensor for the determination of a representation of a temperature prevailing at the PM sensor. These elements for the determination of a temperature may be integrated with the PM sensor, i.e. may use joint components such as substrate or similar, or e.g. consist of a separate temperature sensor incorporated into a joint housing with the PM sensor.

PM sensors may also comprise elements to heat the PM sensor, e.g. in order to regenerate (clean) the PM sensor of gathered soot particles, where needed. According to one embodiment, these elements are used to heat the PM sensor when the temperature is determined.

By determining a temperature change at the PM sensor, this temperature change may be compared with an expected

temperature change, and based on the comparison, it may be determined whether the PM sensor may be deemed to be subject to a representative exhaust stream, i.e. an exhaust stream which correctly reflects the composition in the exhaust stream which leaves the combustion chamber of the combustion engine. If e.g. a temperature increase is expected, e.g. due to an increased combustion engine load, while the PM sensor fails to show a similar temperature increase or even a temperature decrease, it may be assumed that the PM sensor was not exposed to a representative exhaust stream.

By combining the method according to the present invention with one or more of the above described methods, a more reliable evaluation of the PM sensor's function may be carried out .

Additionally, the present invention has been exemplified above in relation to vehicles. The invention is, however, applicable to any vessels/processes where particulate filter systems as per the above are applicable, such as e.g. watercrafts and aircrafts with combustion processes as per the above.

Additionally, the combustion engine may e.g. consist of at least one of the group: automotive engine, marine engine, industrial engine, diesel engine, spark ignition engine, GDI engine, gas engine.

Other embodiments of the method and the system according to the invention are available in the patent claims enclosed hereto .

It should also be noted that the system may be modified according to various embodiments of the method according to the invention (and vice versa) and that the present invention is in no way limited to the above described embodiments of the method according to the invention, but pertain to and comprise all embodiments in the scope of the enclosed independent claims .

Claims

1. Method to establish a sensor function for a PM sensor

(213) intended for the determination of a particle content in an exhaust stream resulting from a combustion in a combustion engine (101), where an aftertreatment system (200) is installed for the aftertreatment of the said exhaust stream, and the method is characterised by:

- establishing a first representation of a prevailing concentration and/or fraction (Ci) at the said PM sensor (213) of a first substance (Si) in the said exhaust stream with the use of the elements set up in the said PM sensor (213) for the determination of a representation of a concentration and/or fraction of the said first substance (Si), and

- based on the said established representation of a concentration and/or fraction (Cj) of the said first substance (Si) , confirming whether the said PM sensor (213) emits a signal which is representative of the said exhaust stream.

2. Method according to claim 1, where the said elements for the determination of the said representation of a

concentration and/or fraction of the said first substance (Si) consists of a concentration sensor for the

determination of a representation of a concentration and/or fraction of the said first substance (Si) .

3. Method according to claim 2, where the said concentration sensor consists of a gas concentration sensor (214) and where the said first substance (Si) consists of a gas. . Method according to claim 3, where the said concentration sensor (214) consists of a sensor of electrochemical type, or of a sensor of semiconductor type. Method according to claim 1, where the said first substance (Si) consists of particles in the said exhaust stream, and where the said representation of a

concentration and/or fraction of the said particles is established with the use of the said PM sensor (213) , where the said PM sensor (213) consists of an

electrostatic or resistive PM sensor.

Method according to claim 1, comprising establishing whether the said PM sensor (213) emits a signal

representative of the said exhaust stream by based on the said representation of the said concentration and/or fraction of the said first substance (Si) confirming whether the said PM sensor (213) may be deemed to be present in the said exhaust stream.

Method according to any of the previous claims, further comprising, based on the said confirmed representation of a concentration and/or fraction of the said first substance (Si) , establishing whether the said

aftertreatment system (200) and/or PM sensor (213) may be assumed to have been manipulated.

Method according to any of the previous claims, where the said element (214) for establishing a representation of a concentration and/or fraction of the said first substance (Si) consists of elements integrated with the said PM sensor (213) .

Method according to any of the claims 1-8, where the said element (214) for establishing a representation of a concentration and/or fraction of the said first substance

(Si) consists of elements fixedly connected with and/or incorporated in a joint housing with the said PM sensor

(213) .

10. Method according to any of the previous claims, further comprising :

- comparing the said first concentration and/or fraction (Ci) of the said first substance (Si) with an expected concentration and/or fraction {C_sxp) of the said first substance (Si) , and

- based on the said comparison, establishing whether the said PM sensor emits a signal representative of the said exhaust stream. 11. Method according to claim 10, further comprising:

- establishing a discrepancy (A) between the said first concentration and/or fraction (Ci) of the said first substance (Si) and the said expected concentration and/or fraction (C_exp) of the said first substance (Si) , and - where the said PM sensor (213) is deemed to emit a signal which is not representative of the said exhaust stream if the said discrepancy (A) exceeds a first limit

(Aiimi) .

12. Method according to any of the previous claims, also comprising:

- With the use of the said first element (214) for the determination of a concentration and/or a fraction of the said first substance (Si) , establishing a first change {AC₁₂) of a concentration and/or fraction of the said first substance (Si) ,

- comparing the said first change (ACj₂) of the

concentration and/or fraction of the said first substance (Si) with an expected change (AC_exp) of the concentration and/or fraction of the said first substance (Si) , and - based on the said comparison, establishing whether the said PM sensor emits a signal which is representative of the said exhaust stream.

13. Method according to claim 12, further comprising:

- establishing a discrepancy (A) between the said first change (AC_J2) of the concentration and/or fraction of the said first substance (Si) and the said expected change (ACexp) of the concentration and/or fraction of the said first substance (Si) , and

- where the said PM sensor (213) is deemed to emit a signal which is not representative of the said exhaust stream if the said discrepancy (A) exceeds a second limit (A_lim2) .

14. Method according to claim 11 or 13, where the said

discrepancy (A) is confirmed as an absolute amount of a difference between the said first concentration and/or fraction (Cj) and the said expected concentration and/or fraction (C_SXp) , or as an absolute amount of a difference between the said first change (ΔΟ^) and the said expected change (AC_Sx_P) of the concentration and/or fraction of the said first substance (Si) .

15. Method according to any of claims 10-14, further

comprising :

- establishing a discrepancy between the said first concentration and/or fraction (Cj) of, or change (ACi^) of concentration and/or fraction of the said first substance (Si) and the said expected concentration and/or fraction (C_eXp) of, or said expected change (AC_exp) of concentration and/or fraction of the said first substance (Si) at a number of points in time, and

- where the said PM sensor (213) is deemed to emit a signal which is not representative of the said exhaust stream if the said discrepancy (A) exceeds the said limit ( iirni; Ai_im2) for at least some of the said points in time.

16. Method according to any of claims 10-15, further comprising :

- establishing a discrepancy between the said first concentration and/or fraction (Cj) of, or change (ΔΟΙΣ) of concentration and/or fraction of the said first substance

(Si) and the said expected concentration and/or fraction (Csxp) of, or the said expected change (AC_{s p}) of

concentration and/or fraction of the said first substance (Si) at a number of points in time, and

- where the said PM sensor (213) is deemed to emit a signal which is not representative of the said exhaust stream if the overall value of the said discrepancies (A) for the said number of points in time exceeds the said limit (Aiimi; Ai_im2) . 17. Method according to any of the previous claims, also

comprising :

- establishing the said first representation of a concentration prevailing at the said PM sensor (213) and/or fraction (Cz) of a first substance (Si) occurring in the said exhaust stream with the help of frequency analysis of a signal emitted by one of the said elements for the determination of a representation of a

concentration and/or fraction of the said first substance (Si) . 18. Method according to any of the claims 10-17, comprising the generation of a signal indicating a malfunction for the said PM sensor (213) when the said first

concentration and/or fraction (Cj) of, or change (A i^) of the concentration and/or fraction of the said first substance (Si) is not consistent with an expected (C_exp) concentration and/or fraction of, or expected change (AC_sxp) of the concentration and/or fraction of, the said first substance (Si) .

9. Method according to any of the claims 10-18, also

comprising actively impacting the said change of

concentration and/or fraction of the said first substance (Si) by actively impacting the said exhaust stream.

0. Method according to claim 19, further comprising actively impacting the said exhaust stream by controlling the said combustion engine, such as by way of control of at least one of the fuel injection times, fuel injection

durations, fuel injection amount, fuel pressure, number of fuel injections, EGR and air supply, vent times, compression conditions, overload, VGT position, engine speed, change of combustion mode of the said combustion engine, e.g. from Otto to HCCI or from Diesel to PPC.

1. Method according to claim 19 or 20, where the said method further comprises actively impacting the said exhaust stream through control of throttles installed for

controllable throttling of the said exhaust stream.

2. Method according to claim 21, where the said method further comprises actively impacting the said exhaust stream through control of throttling elements installed downstream of a position intended for the said PM sensor.

3. Method according to claims 21 or 22, further comprising actively impacting the said exhaust stream through controllable throttling of the said exhaust stream with throttling elements in the form of an exhaust brake.

24. Method according to any of the claims 19-23, also

comprising actively impacting the said exhaust stream by supply of hydrocarbon to the exhaust stream.

25. Method according to any of the claims 19-24, further comprising actively impacting the said exhaust stream upstream or downstream of a turbine.

26. Method according to any of the claims 19-25, further

comprising actively impacting the said exhaust stream through bypassing of one or several components in the said aftertreatment system (200) , or by connecting another component for the passage of, and thus bypassing the said particle sensor (213) of, at least a part of the said exhaust stream.

27. Method according to any of the previous claims, where the said aftertreatment system (200) comprises at least one particulate filter (202) , and where the intended PM sensor position is upstream or downstream of the said particulate filter (202) in the said exhaust stream.

28. Method according to any of the previous claims, where the said aftertreatment system (200) comprises at least one particulate filter (202) and where the intended PM sensor position is upstream or downstream of a component with which a concentration and/or fraction of the said first substance may change, such as a turbine, DOC or SCR catalyst .

29. Method according to any of the previous claims, where the said combustion engine consists of an engine in a

vehicle, and where the output power from the said

combustion engine is limited by the use of a control system set up in the said vehicle if the said PM sensor does not emit a signal representative of the said exhaust stream.

0. Method according to any of the previous claims, further comprising, by use of the said element for the

determination of a concentration and/or fraction of a first substance d) occurring in the said exhaust stream, establishing the concentration and/or fraction for at least one other substance occurring in the said exhaust stream, and

- establishing whether the said PM sensor emits a signal representative of the said exhaust stream based on concentrations and/or fractions of the said first (Si) as well as at least one additional substance.

1. Method according to claim 30, also comprising

establishing a particle concentration and/or fraction with the help of the said PM sensor (213) , where the said particle concentration and/or fraction constitutes the concentration and/or fraction for the said additional substance occurring in the said exhaust stream.

2. Method according to any of the previous claims, where the method also comprises:

- establishing a representation of a first pressure at the said PM sensor by the use of a pressure sensor set up in the said PM sensor, and

- establishing whether the said PM sensor emits a signal representative of the said exhaust stream also based on the said established first pressure.

3. Method according to any of the previous claims, where the method also comprises:

- establishing a representation of a first temperature at the said PM sensor with the use of elements installed in the said PM sensor to emit a representation of a

temperature prevailing in the PM sensor (213), and - establishing whether the said PM sensor emits a signal representative of the said exhaust stream also based on the said first temperature established.

34. Method according to any of the previous claims, where the said vehicle comprises elements for the supply of

additives to the said exhaust stream, and where the supply of additives is interrupted when the sensor function for the said PM sensor (213) is established.

35. Method according to any of the previous claims, where the said first substance consists of any out of the group: hydrocarbons, ammonia, oxygen, particulates, nitrogen oxide, nitrogen dioxide, carbon monoxide, carbon dioxide.

36. Computer program comprising a program code which, when the said program code is executed in a computer, achieves that the said computer carries out the method according to any of the patent claims 1-35.

37. Computer program product including a computer readable medium and a computer program according to patent claim 36, where the said computer program is comprised in the said computer-readable medium.

38. Method to establish a sensor function for a PM sensor intended for the determination of a particle content in an exhaust stream resulting from a combustion in a combustion engine (101), where an aftertreatment system (200) is installed for the aftertreatment of the said exhaust stream, characterised by the fact that the system comprises :

- elements arranged to establish a representation of a first concentration at the said PM sensor and/or fraction of a first substance (Si) in the said exhaust stream with the use of the elements set up in the said PM sensor for the determination of a representation of a concentration and/or fraction of the said initial substance (Si) , and - elements arranged to, based also on the said

established representation of a concentration of the said first substance (Si) , confirm whether the said PM sensor emits a signal which is representative of the said exhaust stream. System according to claim 38, characterised by the said combustion engine consisting of at least one out of the group: automotive engine, marine engine, industrial engine, diesel engine, spark ignition engine, GDI engine, gas engine.

40. Vehicle (100), characterised by the fact that it

comprises a system according to one of the claims 38 or