• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a method for determination of particle emissions pertaining to a combustion engine, such that a post-treatment system comprising at least one particle filter is provided to post-treat an exhaust flow arising from combustion in said engine. The method comprises - using a PM sensor situated upstream of said particle filter to determine, at a location upstream of said particle filter, a first particle content of said exhaust flow arising from said engine and - using said first particle content determined as a basis for determining whether the particle content of said exhaust flow downstream of said particle filter fulfils a first condition. The invention relates also to a system and a vehicle.
    公开号:SE1151073A1
    申请号:SE1151073
    申请日:2011-11-14
    公开日:2013-05-15
    发明作者:Ola Stenlaaaas
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    10 l5 the after-treatment system in vehicles with a diesel engine often includes a particulate filter.
    When combustion of fuel in the combustion chamber (eg cylinders) of the internal combustion engine, soot particles are formed.
    According to the above, emission regulations and standards also apply to these soot particles, and to comply with the regulations, particulate filters can be used to capture the soot particles. In this case, the exhaust gas flow is led e.g. through a filter structure where soot particles are captured from the passing exhaust stream for storage in the particulate filter.
    Thus, there are several methods for reducing emissions from an internal combustion engine. In addition to regulations regarding emission levels, it is also becoming more common with statutory requirements for in-vehicle diagnostic systems, so-called On-Board Diagnostics (OBD) system to ensure that the vehicle is also in daily operation, and not only in e.g. workshop visits, in fact comply with established regulations regarding emissions.
    Regarding particulate emissions, this can e.g. is achieved by means of a particle sensor arranged in the exhaust pipe of the exhaust system, in the following description and claims called PM sensor (PM = Particulate Matter, Particulate Mass), which measures the particle content in the exhaust stream before the exhaust stream is released into the vehicle's surroundings.
    Particulate filter after-treatment systems can be very effective, and the resulting particle content after the exhaust stream passes through the vehicle's after-treatment system is often low with a fully functioning after-treatment system. This also means that the signals emitted by the sensor will indicate low or no particulate emissions.
    SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for determining 105 particle emissions in a vehicle. This object is achieved with a method according to claim 1.
    The present invention relates to a method for determining particulate emissions in an internal combustion engine, wherein a post-treatment system comprising at least one particulate filter is arranged for post-treatment of an exhaust gas resulting from combustion in said internal combustion engine. The method comprises: - for a position upstream of said particulate filter and by using a PM sensor arranged upstream of said particulate filter, determining a first particle content in said exhaust gas resulting from said internal combustion engine, and - based on said determined first particulate content, determining whether the particulate content in said exhaust stream said particle filter fulfills a first condition.
    By determining a particle content for a position upstream of said particle filter and then based on this particle content determining whether the particle content downstream of the particle filter meets a first condition, such as being below a second particle content, it can e.g. is determined whether the particle content in the after-said particle filter in the environment of the internal combustion engine, such as e.g. a vehicle environment, the exhaust gas emissions are subject to prescribed regulations. These provisions can e.g. consists of a maximum permissible particle content determined by e.g. particulate mass per engine power unit, such as a certain particulate mass per kW of developed or deliverable engine power, whereby also the said conditions may consist of the emitted particulate content must comply with the regulations. For example. said second particle content may be set to a content which exactly or by the desired margin satisfies the provisions. As explained below, the condition, such as the second particle content, can also be set to a higher content compared to the provisions. According to the invention, the invention further has the advantage that problems in ensuring the reliability of the sensor in sensor solutions of the type described above can be reduced, whereby also an improved method for determining particulate emissions during combustion with an internal combustion engine can be provided.
    In one embodiment, the internal combustion engine itself may meet the prevailing provisions, wherein the particle content in said exhaust stream downstream of said particulate filter may be arranged to meet said first condition if said determined first particulate content meets said first condition. In another embodiment, the particulate content in said exhaust stream downstream of said particulate filter may be arranged to meet said first condition if said determined first particulate content meets a certain ratio to said maximum allowable particulate emissions, such as e.g. maximum constitute said maximum permissible particulate emissions multiplied by any applicable factor.
    According to one embodiment, said first condition depends on a differential pressure across the particle filter, where e.g. a condition in the form of a particle content may depend on the differential pressure so that the particle content to which said first particle content may amount to a maximum may be arranged to decrease in step with increasing differential pressure.
    The present invention also has the advantage that the PM sensor, due to the higher particle content in the exhaust gas stream upstream of the particulate filter, will more frequently and more or less regularly emit a signal indicating that soot is present in the exhaust gas stream. The signal will thus also be significantly more reliable, and therefore also easier to diagnose.
    For example. can, in contrast to sensor placement downstream of the particle filter as above, a suddenly absent signal 10 l 15 can be directly analyzed and e.g. be used as an indication that the sensor is malfunctioning. Placing the PM sensor upstream also has the advantage that the sensor can be placed with great certainty in such a way that it will be passed by a well-mixed and homogeneous exhaust stream without major distribution problems, whereby a more correct measured value can also be ensured.
    Thus, the present invention enables monitoring that particulate emission regulations after the particulate filter are met without actually having to measure particulate matter after the particulate filter, and even in engines where the particulate content of the exhaust stream upstream of the particulate filter does not meet current regulations.
    Additional features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments and the accompanying drawings.
    Brief Description of the Drawings Fig. 1a schematically shows a vehicle in which the present invention can be used.
    Fig. 1b shows a control unit in the control system for the vehicle shown in Fig. 1.
    Fig. 2 shows the finishing system in more detail for the vehicle shown in Fig. 1.
    Fig. 3 shows an exemplary method according to the present invention.
    Detailed description of embodiments In the following description and the following claims, the term particulate content includes both content in the form of mass per unit and content / concentration, ie. number of particles per unit.
    Furthermore, the unit can consist of any applicable unit and the content is expressed as e.g. mass or number of particles per unit volume, per unit time, per work performed, or per distance traveled by the vehicle.
    Fig. 1a schematically shows a driveline in a vehicle 100 according to an embodiment of the present invention. The vehicle 100 schematically shown in Fig. 1 comprises only one axle with drive wheels 113, 114, but the invention is also applicable to vehicles where more than one axle is provided with drive wheels. The driveline comprises an internal combustion engine 101, which is connected in a conventional manner, via a shaft outgoing on the internal combustion engine 101, usually via a flywheel 102, to a gearbox 103 via a clutch 106. The internal combustion engine 101 is controlled by the vehicle control system 115. the coupling 106, which e.g. may be an automatically controlled clutch, and the gearbox 103 of the vehicle control system by means of one or more applicable control units (not shown). Of course, the driveline of the vehicle can also be of another type such as of a type with conventional automatic transmission etc.
    A shaft 107 emanating from the gearbox 103 then drives the drive wheels 113, 114 via an end gear 108, such as e.g. a conventional differential, and drive shafts 104, 105 connected to said final gear 108.
    The vehicle 100 further includes an after-treatment system (exhaust purification system) 200 for treating (purifying) exhaust emissions resulting from combustion in the internal combustion engine 101 combustion chamber (eg, cylinders).
    The after-treatment system is shown in more detail in Fig. 2. The figure shows the internal combustion engine 101 of the vehicle 100, where the exhaust gases generated during combustion are led via a turbocharger 220. In turbocharged engines, the exhaust gas resulting from combustion often drives a turbocharger which in turn compresses the incoming air for the combustion of the cylinders. Alternatively, the turbocharger can e.g. be of compound type. The function for different types of turbochargers is well known, and is therefore not described in more detail here. The exhaust stream is then passed via a pipe 204 (indicated by arrows) to a particulate filter (DPF) 202 via an oxidation catalyst (Diesel Oxidation Catalyst, DOC) 205.
    The oxidation catalyst DOC 205 has several functions, and is normally used primarily to oxidize residual hydrocarbons and carbon monoxide in the exhaust stream to carbon dioxide and water. During the oxidation of hydrocarbons (ie oxidation of fuel) heat is also formed, which can be used to raise the temperature of the particle filter during emptying, so-called regeneration, of the particle filter.
    The oxidation catalyst can also be used to oxidize nitrogen monoxide (NO) to nitrogen dioxide (NO 2), which can be used in so-called passive regeneration.
    Finishing systems of the type shown may also include other components such as e.g. a (in the present example) SCR (Selective Catalytic Reduction) catalyst 201 arranged downstream of the particulate filter 202. SCR catalysts use ammonia (NH3), or a composition from which ammonia can be generated / formed, as an additive for reducing the amount of nitrogen oxides NOX.
    Furthermore, the finishing system 200 may also include more components than have been exemplified above, or conversely fewer components. For example. the after-treatment system in addition to, or instead of, the said DOC 205 and / or SCR 201 may comprise an ASC (ammonia slip) catalyst (not shown). In the embodiment shown, DOC 205, DPF 202 and also the SCR catalyst 201 are integrated in one and the same exhaust gas purification unit 203. However, it should be understood that DOC 205 and DPF 202 do not have to be integrated in one and the same exhaust gas purification unit, but the 105 units can be arranged in other ways where appropriate.
    According to the present invention, the post-processing system 200 comprises an upstream DPF 202 arranged PM sensor 222. The PM sensor 222, as well as other sensors arranged at the post-processing system 200, such as e.g. a pressure sensor 209 may output signals to a controller 208, or other applicable controller, which controls or monitors the operation of the finishing system. For example. determining the appropriate time for regeneration of the particulate filter can be performed by means of the control unit 208 at least in part by means of signals from the pressure sensor 209, which measures the differential pressure across the particulate filter. The more the particle filter 202 is filled, the larger the pressure difference across the particle filter 202 will be.
    The pressure sensor 209 can e.g. can also be used in the diagnosis of DPF 202, but also in determining whether a particle content after the particle filter meets a condition of the present invention, as described below.
    In general, control systems in modern vehicles consist of a communication bus system consisting of one or more communication buses for interconnecting a number of electronic control units (ECUs) such as the control units, or controllers, ll5, 208, and various components located on the vehicle. Such a control system can comprise a large number of control units, and the responsibility for a specific function can be divided into more than one control unit.
    For the sake of simplicity, in Fig. 1a only the control units 115, 208 are shown.
    In the embodiment shown, the present invention is implemented in the control unit 208, which in the embodiment shown above is responsible for other functions in the finishing system, such as e.g. regeneration (emptying) of the particle filter 202, but the invention may just as well be implemented in a control unit dedicated to the present invention, or wholly or partly in one or more other control units already present in the vehicle, such as e.g. motor control unit 115.
    The function of the control unit 208 (or the control unit (s) to which the present invention is implemented) according to the present invention will, in addition to being dependent on sensor signals from the PM sensor 222, be likely to e.g. depend on information such as received from the control unit (s) controlling motor functions, ie in the present example the control unit 115.
    Control units of the type shown are normally arranged to receive sensor signals from different parts of the vehicle. The control unit 208 can e.g. receive sensor signals as above, as well as from the motor control unit 115 and other control units. Furthermore, such control units are usually arranged to emit control signals to various vehicle parts and components. For example. the control unit 208 can emit signals to e.g. motor control unit 115.
    The control is often controlled by programmed instructions. These programmed instructions typically consist of a computer program, which when executed in a computer or controller causes the computer / controller to perform the desired control, such as method steps of the present invention.
    The computer program usually forms part of a computer program product, the computer program product comprising a digital storage medium 121 (see Fig. 1b) with the computer program 109 stored on said storage medium 121. Said digital storage medium 121 may e.g. consists of someone from the group: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically Erasable PROM), a hard disk drive, etc., and be arranged in or in connection with the control unit, the computer program being executed by the control unit. By following the instructions of the other computer program, the behavior of the vehicle in a specific situation can thus be adapted.
    An exemplary control unit (control unit 208) is shown schematically in Fig. 1b, wherein the control unit may in turn comprise a calculation unit 120, which may consist of e.g. any suitable type of processor or microcomputer, e.g. a Digital Signal Processor (DSP), or an Application Specific Integrated Circuit (ASIC). The computing unit 120 is connected to a memory unit 121, which provides the computing unit 120 e.g. the stored program code 109 and / or the stored data calculation unit 120 need to be able to perform calculations. The calculation unit 120 is also arranged to store partial or final results of calculations in the memory unit 121.
    Furthermore, the control unit is provided with devices 122, 123, 124, 125 for receiving and transmitting input and output signals, respectively. These input and output signals may contain waveforms, pulses, or other attributes, which of the input signals 122, 125 may be detected as information for processing the calculation unit 120. The output signals 123, 124 for transmitting output signals are arranged to convert calculation results from the calculation unit. 120 to output signals for transmission to other parts of the vehicle's control system and / or the component (s) for which the signals are intended. Each of the connections to the devices for receiving and transmitting input and output signals, respectively, may be constituted by one or more of a cable; a data bus, such as a CAN bus (Controller l0 l5 ll Area Network bus), a MOST bus (Media Oriented Systems Transport), or any other bus configuration; or by a wireless connection.
    As mentioned, particles are formed during combustion in the combustion chamber (usually cylinders) of the internal combustion engine 101. As stated above, these particles should not, and in many cases should not, be released into the vehicle's environment. The particles that are formed during combustion in e.g. a diesel engine consists largely of hydrocarbons, carbon (soot) and inorganic substances such as sulfur and ash. Soot particles can e.g. is formed when the fuel / air ratio during combustion in the combustion chamber of the internal combustion engine becomes too large, ie. at s.k. "Greasy" fuel mixture with too high a proportion of fuel in relation to the proportion of air. Even if the fuel / air ratio for a specific combustion, ie. the injection amounts of air and fuel at a specific piston stroke, may be such that the requirements for non-sooty combustion are met, fuel / air conditions may still occur locally in parts of the combustion chamber where the proportion of fuel is higher, and the mixture is thus fatter, these locally fatter mixtures can give rise to soot during combustion.
    Likewise, soot can be formed by e.g. oil splashes from the engine lubrication that have entered the combustion chamber via e.g. movements of the piston. Furthermore, e.g. metal fragments from wear and / or manufacture of the engine give rise to particle formation. Regarding the vehicle's fuel, this can be more or less “clean”, and thus in itself give rise to different particle formation during combustion.
    These soot particles are thus collected by the particulate filter 202 by passing the exhaust stream through the filter structure of the particulate filter where the soot particles are captured from the 12 passing exhaust stream and then stored in the particulate filter 202. By means of a particulate filter 202 a very large proportion of the particles present in the exhaust stream dissever.
    In some jurisdictions, there are already developed, and in other jurisdictions, statutory requirements are expected that the vehicle with the help of its own systems, so-called OBD (On-Board Diagnostics) system, also in commercial operation, and not only in e.g. workshop inspection checks, must be able to ensure that the vehicle's particulate emissions remain below prescribed levels.
    This can be achieved in a relatively straightforward manner by placing a particle sensor (PM sensor) at the finishing pipe of the finishing system, ie. substantially at the position where the exhaust gas flow is discharged into the vehicle environment.
    This location is indicated by 221 in Fig. 2. By then monitoring sensor signals from the sensor 221, e.g. by means of a control unit corresponding to the control unit 208, it can be ensured that the particle content in the exhaust gas stream leaving the vehicle also falls below prescribed levels.
    However, this sensor placement has disadvantages.
    Particle collection from the exhaust stream by means of a particle filter is usually so efficient that the amount of particles that actually leave the vehicle is generally very small when the particle filter functions properly.
    This means that as long as the particle filter works in the intended manner, it will be difficult to know that the sensor actually works, since the signals then emitted by the sensor will indicate no or very low particle contents. Experiments have shown that the particle levels in an exhaust gas stream after passage through a particle filter can be so low that for many sensors it can take a long time 13 (for example in the order of 5-15 minutes) before a signal is emitted where particle presence is indicated at all.
    This applies not only to normal driving of the vehicle, but also to provocation, ie. in situations where the combustion engine is intentionally controlled for test purposes in such a way that high particulate contents are to be emitted.
    Thus, it can be difficult to know if the sensor is actually intact and functioning as expected, since sensor signals where no or low particle levels are indicated are at best a result of the aftertreatment system functioning flawlessly, but where the sensor signals can also be a result of the PM sensor 221 is malfunctioning.
    The location 221 indicated in Fig. 2 further has the disadvantage that in cases where the particle filter functions incorrectly, e.g. due to the sudden occurrence of a mechanical fault, and thus causing markedly increased particulate emissions, it is very difficult to predict how the flow path of the exhaust stream will change in such situations, whereby, depending on the flow wave, it is not certain that the PM sensor is placed on in such a way that the elevated particle levels will actually be detected.
    This disadvantage can be mitigated by placing a mixer after the particle filter, but still upstream of the PM sensor, to homogenize the exhaust gas flow, and thus increase the probability that elevated particle concentrations are also detected by the PM sensor. However, such mixers naturally give rise to a pressure drop, which entails, in addition to costs for the mixer, an undesirable increase in fuel consumption. Alternatively, the flow path between the particle filter and the PM sensor can be extended by a solution with longer pipes, but this also entails increased cost. 14 However, even these solutions still suffer from the above-mentioned problems with uncertainty in the function of the sensor. Although this uncertainty can be mitigated by the use of several sensors, in addition to increased cost, the problem still remains that the sensors emit signals so infrequently that correct function is difficult to ensure, and it is also difficult to ensure that the vehicle's emissions do not exceed the prescribed levels.
    As above, the PM sensor of the present invention is placed upstream of the particulate filter instead of downstream of the particulate filter, as shown in Fig. 2 with the sensor 222. By means of the inventive method of determining by means of the upstream particulate filter 222 the vehicle 100 emissions below prescribed levels, such problems can be reduced or completely eliminated.
    A method 300 according to the present invention for determining a particulate emission is shown in Fig. 3. According to the embodiment shown, the method is implemented in the control unit 208, and the method begins in step 301, where it is determined whether the internal combustion engine 101 of the vehicle 100 is started. If the internal combustion engine 101 is started, the process proceeds to step 302, otherwise the process remains in step 301, or ends.
    In step 302, it is determined whether signals are received from the PM sensor 222.
    The method remains in step 302 until sensor signals are obtained, however, until a timer t1 has reached a time T1.
    If no sensor signals have been received before the counter has reached the time T1, which e.g. may be a part of a second or an applicable number of seconds, the procedure proceeds to a step 303 for diagnosis of the sensor, see below. If, on the other hand, sensor signals have been obtained within time T1, the process proceeds to step 304 for determining a particle content in the exhaust gas stream.
    In step 304, a first particle content is determined by means of the signals emitted by the PM sensor 222. Since the determination is made by means of a PM sensor 222 arranged upstream of the particulate filter 202, a continuous flow of particles will constantly pass the sensor 222 when the internal combustion engine 101 is in operation.
    This also means that the particle content at the sensor 222 will be significantly higher compared to the particle content downstream of the particle filter, whereby the PM sensor 222 when measuring according to the present invention will emit a continuous signal. This signal will be emitted faster because the higher particle content means that the smallest amount of particles required for the PM sensor to indicate the presence of particles will be achieved more quickly. In addition, the signal will indicate a higher amount of particles, which is thus easier to both size and diagnose.
    In addition to the fact that the PM sensor 222 will be located in an environment where the exhaust stream has a higher particle content, placement of the sensor upstream of the particulate filter also has the advantage that the sensor can be placed in such a way that it will be located in a well mixed and homogeneous exhaust stream. be able to perform measurement on a representative part of the exhaust stream. In the embodiment shown, the PM sensor 222 is arranged upstream of both DPF 202 and DOC 205. As exemplified below, however, the PM sensor 222 may be located at a number of other positions (though still upstream of the particulate filter 202).
    After a first particle content has been determined in step 304 by the PM sensor 222, the procedure proceeds to step 305, where the determined first particle content is compared with a second particle content.
    If it is determined in step 305 that the particle content determined in step 304 exceeds said second particle content, the process proceeds to step 307 for further investigation. For example. For example, steps 301-305 may be repeated one or more times until the steps have been traversed y times, the actual number of times x being counted each time the procedure proceeds to step 307.
    The procedure can e.g. return to step 301 from step 307 when a timer tg has counted to a time T2, such as an applicable number of seconds. By proceeding in this way, it can be determined whether the elevated particle content was only temporary and then dropped below the prescribed level again. If elevated levels remain after the mentioned number of determinations, ie. xäy, the process can proceed to a step 308 to ascertain, if possible, by means of diagnosis the reason for the elevated levels. This diagnosis can e.g. carried out using the diagnostic procedure described in the parallel Swedish application entitled "PROCEDURE AND SYSTEM FOR DIAGNOSIS OF AN COMBUSTION ENGINE" and the same inventor and filing date as the present application. According to said application, a method is provided for diagnosing an internal combustion engine in a vehicle where a particle content in an exhaust stream from said internal combustion engine is determined at a position upstream of a particulate filter by means of an PM sensor arranged upstream of the particulate filter. Using the determined particle content, it is determined whether the internal combustion engine is malfunctioning. The procedure shown allows malfunctions to be detected at a very early stage, and appropriate action to be taken. Errors that might otherwise not be detected until a much later time, e.g. in connection with a workshop visit, with the aid of the procedure described in the said application can be detected significantly earlier.
    Alternatively, e.g. a service indicator is inserted in the vehicle's control system e.g. together with an error code for the excessive particle emissions, whereby the vehicle 100 can be taken in for service as soon as possible.
    If said first particle content is below said second particle content, the process proceeds to step 306, where it is determined that the emission levels of the vehicle 100 are less than the prescribed levels applicable to the vehicle. With the aid of said determined first particle content it can thus be determined whether the particle content in the exhaust gas stream downstream of said particle filter fulfills a certain condition, such as e.g. that said second particle content is below. The process is then terminated in step 309.
    Said second particle content can e.g. consists of the maximum particulate matter that may be emitted by the vehicle in accordance with the applicable regulations, and may thus be different for different vehicles, but also different for similar vehicles operated in different jurisdictions with different provisions regarding particulate emissions. Emissions are usually normalized to a specific driving cycle, and said second particle content can e.g. is determined by the permissible particle quantity per kWh of work performed by the internal combustion engine, ie. the more work the internal combustion engine performs, the higher emissions are allowed in the exhaust stream. In general, emission regulations are often expressed in particulate matter per unit of engine work, such as e.g. kg / kWh, g / kWh or mg / kWh, where the engine work e.g. may constitute developed or releasable engine power.
    However, this second particle content can also consist of a higher particle content compared to current regulations. The said second particle content can thus depend on different parameters, and in step 305 the second particle content can e.g. determined as a function of one or more of pressures before and after the particulate filter, differential pressure across the particulate filter, time, exhaust gas temperature and exhaust gas flow, where such data e.g. can be used to determine a second particulate matter that meets current emission regulations.
    Today, many engines from different engine manufacturers emit too high a particle content from the combustion engine's combustion for particulate matter regulations to be met without aftertreatment with a particulate filter.
    However, there are engines, such as at least some engines made of e.g. Scania, which shows such good combustion that the combustion's resulting emissions of particles meet the regulations regarding PM emissions even before the exhaust gas stream reaches the particulate filter. The particulate filter is thus used in these engines to further purify the exhaust gas stream.
    Thus, according to one embodiment, according to the above-mentioned second particulate content in step 305 may constitute a statutory emission level, and the present invention is thus very applicable to engines where prescribed emission levels can be maintained even before particulate filtration. By determining that the particulate mass is already below the statutory level before the particulate filter, the particulate content will automatically remain below the statutory level even after DPF, even if DPF were to function incorrectly.
    The invention thus makes it possible to monitor that regulations regarding particulate emissions after the particulate filter are fulfilled without the measurement of particulate content after the particulate filter actually having to be performed.
    In cases where engines are used, where determinations regarding particulate emissions cannot be fulfilled without subsequent particulate filter treatment, said second particulate content may consist of a higher value compared with current regulations.
    For example. the second particle content may be set taking into account the cleaning ability of the particle filter, which e.g. can be theoretically determined or measured. In this way, said second particle content can be set to a level which, although higher than the prescribed provisions, will still ensure that the particle content actually leaving the vehicle is still below the prescribed level.
    As particles are separated from the exhaust stream by means of the particle filter 202, the separated particles accumulate in the particle filter 202, this being filled up with soot over time.
    Depending on e.g. current driving conditions, the driver's driving style and vehicle load, a larger or smaller amount of soot particles will be generated, and soot / particle filling will take place more or less quickly. When the filter is filled to a certain level, the filter must be "emptied", which is done with the help of so-called regeneration, which is well known to those skilled in the art.
    Depending on the degree of filling, however, the purification ability of the filter can vary, so that also said second particle content in one embodiment can be arranged to vary depending on the degree of filling of the particle filter 202. The degree of filling can e.g. is determined by signals from a pressure sensor 209, which measures the differential pressure across the particulate filter 202. The more the particulate filter 202 is filled, the larger the pressure difference across the particulate filter 202 will be. Thus, according to one embodiment, said second particle content may be arranged to depend on the differential pressure across the particle filter 202, wherein said second particle content may be arranged to decrease in step with increasing differential pressure.
    In the process described above, particulate emissions are approved based on a single value. According to one embodiment, l15 l5 is instead determined by a plurality of values for said first particle content, these plurality of values then being weighted together to an average value which is compared with said second particle content. According to this embodiment, individual values may be allowed to exceed said second particle content as long as the weighted value is less than said second particle content.
    Furthermore, the procedure shown in Fig. 3 can be repeated at certain intervals, such as e.g. l time / s, l time / min, or other shorter or longer applicable interval.
    Thus, the present invention enables monitoring that particulate emission regulations after the particulate filter are met without actually having to measure particulate matter after the particulate filter, and even in engines where the particulate content of the exhaust stream upstream of the particulate filter does not meet current regulations.
    Placing the PM sensor upstream of the particulate filter to monitor emission regulations has several advantages. Since the sensor is positioned in such a way that measurement signals will be emitted at all times, the function of the sensor can be ensured by considering the signal emitted by the sensor over time.
    As long as the sensor emits a substantially continuous signal, or for similar operating cases emits essentially the same signal, the sensor can be assumed to function correctly. If, on the other hand, the sensor suddenly indicates significantly lower emissions than normal for a given driving case, it can be assumed that the sensor is operating incorrectly, whereby e.g. a service flag can be activated in the vehicle's control system to indicate the need for service.
    Regarding the sensor, this can be of a type that emits e.g. a voltage or current, or which has a capacitance, inductance or resistance which varies depending on the particle occurrence, the control unit 208 then by means of the applicable mathematical ratio or a table can convert the obtained measured value to a corresponding particle content.
    However, the sensor can also be of a type with its own control logic, where the sensor's internal control logic calculates a particle content which is then sent to the control unit 208 via e.g. the vehicle network or a dedicated cable.
    Furthermore, the sensor can be used to detect situations when the particle content in the exhaust stream suddenly exceeds the normal level or level according to regulations. Although the particulate filter itself often ensures that regulations regarding actual emissions in the vehicle's environment are still met, the higher particulate content still indicates that the internal combustion engine does not work properly, whereby even in this situation it is desirable that the vehicle enters service as soon as possible to repair the cause (s) that give rise to the increased particulate matter in the exhaust gases. This is described in more detail in the above-mentioned parallel application entitled "PROCEDURE AND SYSTEM FOR DIAGNOSIS OF AN COMBUSTION ENGINE".
    The present invention also has the advantage that active tests of the function of the sensor can be performed. For example. For example, the internal combustion engine can be intentionally set to operating points that are expected to result in a significantly higher particulate emission. By simultaneously looking at the signals emitted by the sensor, it can be determined whether the sensor signals actually reflect the expected increase in the particle content of the exhaust gas stream. As long as the expected change in the sensor signal is obtained, the sensor can also be assumed to function correctly. If the sensor signals do not increase despite the increased particulate emissions of the driving case, the sensor can be assumed to function incorrectly.
    As mentioned, placing the PM sensor upstream of the particulate filter also has the advantage that the sensor can be placed with greater certainty in a way which means that the sensor signals are representative of the emission current emitted by the internal combustion engine. l0 l5 22 Eg. For example, as in Fig. 2, the sensor can be placed after a turbocharger 220 from which the exhaust stream is usually delivered in a predictable manner. The sensor 222 may also be arranged to be placed e.g. downstream of DOC 205 but upstream of the particulate filter 202. In the embodiment shown, the SCR catalyst 203 is located downstream of the particulate filter 202, but in one embodiment the SCR catalyst is instead located upstream of DPF 202, whereby the PM sensor 222 can be located downstream or upstream of the SCR catalyst.
    The vehicle can also be equipped with a so-called exhaust brake, the sensor 222 e.g. can be arranged upstream of this exhaust brake. Similarly, the sensor 222 may be located in the EGR feedback of a portion of the exhaust stream that is common to vehicles of the above type since this portion of the exhaust stream is representative, in composition, of the total exhaust stream. The sensor 222 can also e.g. be arranged upstream of the turbocharger 220. The turbocharger can be both of the fixed geometry (FGT) type, of the variable geometry (VGT) type and be equipped with a turbine intended for power return to the crankshaft (turbo compound) or to another part of the driveline. Furthermore, the vehicle may be provided with a so-called ammonia abrasive catalyst (ASC), the PM sensor being arranged upstream or downstream thereof. Thus, there are a large number of possible locations of the PM sensor upstream of the particle filter.
    Furthermore, the said second particle content has so far been referred to in relation to various provisions. However, this value can, e.g. in jurisdictions where regulations are lacking, may also be set at a value determined by the vehicle manufacturer. For example. the value can be set based on a value that ensures good motor function. Furthermore, the present invention has been exemplified above in connection with vehicles. However, the invention is also applicable to arbitrary vessels / processes where particulate filter systems according to the above are applicable, such as e.g. water or aircraft with combustion processes as above.
    Further embodiments of the method and system according to the invention are found in the appended claims.
    It should also be noted that the system may be modified according to various embodiments of the method of the invention (and vice versa) and that the present invention is in no way limited to the above described embodiments of the method of the invention, but relates to and includes all embodiments within the appended dependent the scope of protection of the requirements.
    权利要求:
    Claims (18)
    [1]
    A method for determining particulate emissions in an internal combustion engine, wherein a post-treatment system (200) comprising at least one particulate filter (202) is arranged for post-treatment of an exhaust gas resulting from combustion in said internal combustion engine (101), wherein the method is characterized in that: - for a position upstream of said particulate filter (202) and by using a PM sensor (222) arranged upstream of said particulate filter, a first particle content in said exhaust gas resulting from said internal combustion engine (101), and - based on said determined first particulate content determining whether a particulate content in said exhaust stream downstream of said particulate filter (202) satisfies a first condition.
    [2]
    The method of claim 1, wherein the particulate content released after said particulate filter (202) meets said first condition when said first particulate content is less than a second particulate content.
    [3]
    A method according to claim 2, wherein said second particulate content constitutes a maximum permissible particulate emission for said internal combustion engine.
    [4]
    A method according to claim 2, wherein said second particulate content constitutes a maximum permissible particulate emission for said internal combustion engine multiplied by a first factor.
    [5]
    A method according to any one of claims 1-4, wherein said particle contents are determined as one of the group: - a number of particles or a mass of particles per 10 unit of volume; - a particle number or a particle mass per unit time; a number of particles or a mass of particles per work performed.
    [6]
    A method according to any one of claims 1-5, wherein said first conditions depend on the operation of the internal combustion engine.
    [7]
    A method according to any one of claims 1-6, wherein said first condition depends on the degree of filling of the particle filter (202).
    [8]
    The method of claim 7, wherein said particulate content in said exhaust stream downstream of said particulate filter (202) meets said first condition when said first particulate content is below a second particulate content, said second particulate content changing with increasing degree of filling.
    [9]
    A method according to any one of claims 1-8, wherein said first condition is due to a differential pressure across the particle filter (202).
    [10]
    A method according to any one of claims 1-9, wherein a first particulate content in said exhaust gas resulting from said internal combustion engine (101) for a position upstream of said particulate filter (202) is determined for a plurality of times, and - wherein the particulate content in said exhaust stream downstream of said particulate filter (202) satisfies said first condition when a weighted value of the particulate matter determinations for said plurality of times satisfies said first condition. 10 15 20 25 11 12 13 14. 26.
    [11]
    A method according to any one of claims 1-10, wherein the method further comprises determining a function of said PM sensor based on a sensor signal emitted by said PM sensor representing a particle content in said exhaust gas stream. .
    [12]
    The method of claim 11, wherein said function is determined based on variations in said sensor signal. .
    [13]
    The method of claim 11 or 12, further comprising: - controlling the particulate content emitted by said internal combustion engine by controlling the engine, such as by controlling at least one of the fuel, EGR and air supply to said combustion, and - determining whether it said signal emitted by the PM sensor corresponds to an expected sensor signal.
    [14]
    A method according to any one of claims 11-13, comprising generating a signal indicating a malfunction of said sensor when the signal emitted by said PM sensor does not correspond to the expected sensor signal.
    [15]
    A computer program comprising program code, which when said program code is executed in a computer causes said computer to perform the method according to any one of claims 1-14.
    [16]
    A computer program product comprising a computer readable medium and a computer program according to claim 15, wherein said computer program is included in said computer readable medium.
    [17]
    A particle emission determination system for an internal combustion engine, wherein a post-treatment system (200) comprising at least one particulate filter (202) is 10
    [18]
    Arranged for post-treatment of an exhaust gas stream resulting from combustion in said internal combustion engine (101), characterized in that the system comprises: - means for, for a position upstream of said particulate filter (202) and by using an upstream said particulate filter arranged PM- sensor (222), determining a first particulate content in said exhaust stream resulting from said internal combustion engine (101), and means for determining based on said determined first particulate content whether a particulate content in said exhaust stream downstream of said particulate filter (202) satisfies a first condition. Vehicle (100), characterized in that it comprises a system according to claim 17.
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    同族专利:
    公开号 | 公开日
    BR112014011485A2|2017-05-09|
    SE536180C2|2013-06-18|
    EP2780563B1|2019-07-24|
    CN103930660A|2014-07-16|
    US20140290217A1|2014-10-02|
    EP2780563A4|2015-11-18|
    EP2780563A1|2014-09-24|
    WO2013074022A1|2013-05-23|
    RU2014124141A|2015-12-27|
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    法律状态:
    2021-06-29| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    SE1151073A|SE536180C2|2011-11-14|2011-11-14|Method and system for determining particulate emissions in an internal combustion engine|SE1151073A| SE536180C2|2011-11-14|2011-11-14|Method and system for determining particulate emissions in an internal combustion engine|
    PCT/SE2012/051240| WO2013074022A1|2011-11-14|2012-11-13|Method and system pertaining to monitoring particle emissions in combustion engine exhausts|
    US14/357,826| US20140290217A1|2011-11-14|2012-11-13|Method and system pertaining to monitoring particle emissions in combustion engine exhausts|
    RU2014124141/06A| RU2014124141A|2011-11-14|2012-11-13|METHOD AND SYSTEM RELATING TO MONITORING EMISSIONS OF PARTICLES IN EXHAUST GASES OF THE INTERNAL COMBUSTION ENGINE|
    CN201280055958.XA| CN103930660A|2011-11-14|2012-11-13|Method and system pertaining to monitoring particle emissions in combustion engine exhausts|
    BR112014011485A| BR112014011485A2|2011-11-14|2012-11-13|method and system for monitoring particulate emissions in combustion engine exhaust|
    EP12849291.5A| EP2780563B1|2011-11-14|2012-11-13|Method and system pertaining to monitoring particle emissions in combustion engine exhausts|
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