• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
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    • 专利摘要:
    The present invention relates to a method and a system for regulating a temperature T DPF in a particle filter which is situated downstream of an oxidation catalyst in an exhaust cleaning system and has an inlet temperature T in_DPF which is determined at a point between said oxidation catalyst and said particle filter. According to the present invention, a relationship is defined between said inlet temperature T in_DPF to said particle filter and said temperature T DPF in said particle filter and depends on an amount of fuel which passes unburnt through said oxidation catalyst. Said inlet temperature T in_DPF to said particle filter is then regulated on the basis of said relationship so that said temperature T DPF in the particle filter is kept substantially around a predetermined target level for a defined period of time.
    公开号:SE1150763A1
    申请号:SE1150763
    申请日:2011-08-24
    公开日:2012-03-01
    发明作者:Carl-Johan Karlsson；Klas Telborn
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    lOFurthermore, finishing systems, alternatively or incombination with one or more catalysts, include otherscomponents, such as e.g. particulate filter. It also occursparticulate filters and catalysts integrated witheach other.
    During combustion engine combustion in the cylinders is formedsoot particles. Particulate filters are used to capture thesesoot particles, and works in such a way that the exhaust gas flow is conductedthrough a filter structure where soot particles are captured from itpassing the exhaust gas stream and stored in the particulate filter.
    The particulate filter is filled with soot as the vehicle is driven,and sooner or later the filter must be emptied of soot, whichusually accomplished by means of so-called regeneration. AsAs can be seen below, the present invention may be practiced amongother in regeneration. The invention therefore comes tocan be exemplified, in this document is mainly described forits application in regeneration. However, the inventionnot in any way limited to this application, whichalso shown below.
    Regeneration means that the soot particles, which mainlyconsists of carbon particles, is converted to carbon dioxide and / orcarbon monoxide in one or more chemical processes, and essentiallyregeneration can take place in two different ways. On the one hand, regeneration canhappen through so-called oxygen (O2) -based regeneration, also called activeregeneration. During active regeneration, fuel is addedthe exhaust gases, which are intended to burn in oneoxidation catalyst arranged upstream of the particulate filter.
    During active regeneration, carbon is converted with the help of oxygen tocarbon dioxide and heat.
    This chemical reaction requires relatively highparticle filter temperatures to desired reaction rate(emptying speed) should occur at all.
    Instead of, or along with, active regeneration canN02-based regeneration, also called passive regeneration,apply. During passive regeneration, nitric oxide andcarbon monoxide by a reaction between carbon and nitrogen dioxide. The advantagewith passive regeneration is that desired reaction rates,and thus the speed at which the filter is emptied can be achievedat significantly lower temperatures.
    Under certain conditions, the oxidation catalyst is burnednot all of the above fuel, which at the activethe regeneration has been added to the exhaust gases, a certainamount of this fuel reaches the particulate filter. The amount of fuelwhich reaches the particle filter should be burned in the particle filterto meet the emission requirements for hydrocarbons.
    However, heat is generated during the combustion of the fuel bothin the oxidation catalyst and in the particulate filter due to itthe chemical reaction of the combustion (see Equation 1 below).
    The reaction rate of this chemical reaction increasesexponentially with the temperature, which makes it fastuncontrollable with increasing temperatures, and risks risingto temperatures higher than the filter structure can withstand, wherebymelting of the filter structure risks taking place. That's why it isof utmost importance that the temperature of the particle filter is maintaineda substantially even level, at which the combustion takes placefast enough while uncontrolledtemperature rise is prevented.
    Summary of the inventionIt is an object of the present invention thatprovide a method for controlling a temperature ina particulate filter. This object is achieved by the abovemethod according to the characterizing part of claim 1.
    The purpose is also achieved by the above-mentioned system according to itl0l5characterizing part of claim 17. This object is also achievedof the above-mentioned computer program and the above-mentionedthe vehicle.
    According to the present invention, a relationship is utilizedbetween the inlet temperature 1% _w for the particulate filter and forthe actual temperature 15% in the particulate filter, indicating howparticle filter temperature TM changes in relation tochanges in inlet temperature Yäimw. The relationship dependsof HC emissions, ie the amount of fuel that passesthrough the oxidation catalyst without combustion and thereafterreaches the particulate filter where it is burned. The present inventionthus takes into account the heat generated when thisunburned fuel is burned in the particulate filter.
    By basing the regulation of the inlet temperature 7% MT onthis ratio allows the temperature to be 15% in the particulate filterindirectly regulated via the inlet temperature 7% _mW. According tothe invention is thus adjusted, based on the ratio,inlet temperature Tm_m up and down in value, which makes thatthe temperature Tßw in the particle filter can be kept substantiallyconstant around its target temperature.
    This has a great advantage in that the problem of the thermalthe inertia of the filter system is reduced, as the regulation thenperformed at the inlet temperature 1% _mw to the particulate filter,why about 75% of the mass of the filter system, that isthe mass addition from the particulate filter itself, does not contribute tothe thermal inertia. The response time is hereby reduced by approx75%, which greatly reduces the regulatory problem.l0l5Due to the shortened response time, the input temperature can be 7% _mWregulated so that the temperature of 15% in the particulate filter can be maintainedat essentially the same level, for example during the active stageof a regeneration of the particle filter. Temperature T fl q ithe particulate filter can therefore, by utilizing the invention,controlled to be at a level which both ensures efficientregeneration and prevents unwanted temperature rise.
    The present invention is generally applicable toessentially all applications where fuel is addedthe exhaust gas flow and where a temperature profile with small variationsdesired to be monitored for temperatures in the particulate filter and / or fortemperatures after the particle filter. By utilizingthe invention thus knows the particle filter and also componentsdownstream of the particulate filter, such as, for example, adownstream catalyst, is protected against too hightemperatures.
    Additional features of the present invention andbenefits thereof will be apparent from the following detaileddescription of exemplary embodiments and those attachedthe drawings.
    Brief description of the drawingsFig. 1a shows a driveline in a vehicle at whichthe present invention can be used to advantage.
    Fig. 1b shows an example control unit in a vehicle control system.
    Fig. 2 shows an example of a finishing system in onevehicle in which the present invention is advantageousCan be used.
    Fig. 3a shows examples of temperature profiles during regeneration.
    Fig. 3b shows examples of temperature profiles during regeneration.
    Fig. 4 shows a flow chart for a method according tothe invention.
    Detailed description of preferred embodimentsFig. 1a schematically shows a heavy exemplary vehicle 100, such asa truck, bus or the like, according to aexemplary embodiment of the present invention. That in Fig. 1aschematically shown the vehicle 100 comprises a front pair of wheels111, 112 and a rear wheel pair with drive wheels 113, 114. The vehiclefurther comprising a driveline with an internal combustion engine 101,which in a conventional manner, via one on the internal combustion engine101 output shaft 102, is connected to a gearbox 103,for example via a coupling 106.
    A shaft 107 emanating from the gearbox 103 drives the drive wheels113, 114 via a final gear 108, such as e.g. a usualdifferential, and drive shafts 104, 105 connected to saidfinal gear 108.
    The vehicle 100 further includes aafter-treatment system / exhaust purification system 200 for treatment(purification) of exhaust emissions from the internal combustion engine 101.
    The finishing system is shown in more detail in Fig. 2. The figureshows the internal combustion engine 101 of the vehicle 100, where they atthe combustion generated exhaust gases are led via a turbocharger220 (in turbo engines often drives it from combustionresulting exhaust gas a turbocharger which in turncompresses the incoming air to the cylinderscombustion). The function of the turbocharger is very well known,and is therefore not described in more detail here. The exhaust stream is then ledvia a tube 204 (indicated by arrows) to a particle filter202 via an oxidation catalyst (Diesel Oxidation Catalyst,DOC) 205.l0l5The oxidation catalyst DOC 205 has several functions, andutilizes the excess air that the diesel engine process generally hasgives rise to in the exhaust stream as a chemical reactor togetherwith a noble metal coating in the oxidation catalyst.
    The oxidation catalyst is normally used primarily for oxidationresidual hydrocarbons and carbon monoxide in the exhaust gas tocarbon dioxide and water.
    However, the oxidation catalyst can also oxidize a large proportion ofthe nitrogen monoxides (NO) present in the exhaust stream tonitrogen dioxide (NO 2). Additional reactions may also occur inthe oxidation catalyst.
    In the illustrated embodiment of the exhaust gas purification system, DOC205 and DPF 202 integrated in one and the same exhaust gas purification unit203. However, it should be understood that DOC 205 and DPF 202 do not have tobe integrated in one and the same exhaust gas purification unit, withoutthe units can be arranged in other ways where availableappropriate. For example, the DOC 205 may be arranged in more detailthe internal combustion engine l0l.
    The exhaust purification system set shown in Fig. 2 is commonoccurring in heavy vehicles, at least in jurisdictions therehigher emission requirements prevail, but as an alternative tothe oxidation catalyst may instead comprise the particulate filterprecious metal coatings so that those in the oxidation catalystexisting chemical processes instead occur inthe particulate filter, the exhaust gas purification system thus notincludes any DOC 205.
    As mentioned, soot particles are formed at the 101 of the internal combustion enginecombustion. These soot particles should not, and may in many casesnor, are released into the vehicle environment. Diesel particlesconsists of hydrocarbons, carbon (soot) and inorganic substances such assulfur and ash. As mentioned above, these soot particles are trappedl0l5therefore up by the particle filter 202, which works in this waythat the exhaust stream is led through a filter structure theresoot particles are captured from the passing exhaust stream forto then be stored in the particle filter 202. Usingparticulate filter 202 can a very large proportion of the particlesseparated from the exhaust stream.
    As particles are separated from the exhaust stream with the helpof the particle filter 202, the separated ones thus accumulatethe particles in the particle filter 202, this over timefilled with soot. Depending on factors such as currentdriving conditions, the driver's driving style and vehicle load will onegreater or lesser amount of soot particles to be generated, whythis fulfillment happens more or less quickly, but when the filteris met to a certain level, the filter must be "emptied". Ifthe filter is met to too high a level can the vehicleperformance is affected, while also fire hazard, p.g.a.soot accumulation in combination with high temperatures, may occur.
    As above, emptying of particle filter 202 is performed by means ofregeneration where soot particles, carbon particles, in a chemicalprocess is converted to carbon dioxide and / or carbon monoxide. Overtime must thus the particle filter 202 by more or lessregular intervals are regenerated, and determination of appropriatetime for regeneration of the particle filter can e.g. performedby means of a control unit 208, which e.g. can performdetermination of appropriate time (s) at least in partby means of signals from a pressure sensor 209, which measuresdifferential pressure across the particulate filter. The morethe particle filter 202 fills up, the higher it comesthe pressure difference across the particle filter 202 to be.Also current temperatures before and / or afterthe oxidation catalyst 205 and / or before and / or afterthe particulate filter 202 may act in determiningregeneration time. These temperatures can e.g. determinedusing temperature sensors 210-212.
    Normally no regeneration measures are taken as long asthe fill level of the filter is less than a predetermined level.
    For example. the control system control of the filter regeneration can beso arranged that no action is taken as long as that of the filterdegree of filling e.g. falls below any appropriate degree of filling inrange 60-80%. The degree of filling of the filter can be estimated atany suitable way, e.g. using the differential pressureas above, where a certain pressure difference represents a certaindegree of filling.
    The control unit 208 also controls the regulation of the temperature inthe particulate filter of the present invention, whichdescribed in more detail below.
    In general, steering systems in modern vehicles usually consist of onecommunication bus system consisting of one or morecommunication buses to connect a numberelectronic controllers (ECUs), or controllers, andvarious components located on the vehicle. One suchcontrol systems can comprise a large number of control units, andthe responsibility for a specific function can be divided into more thana control unit.
    For the sake of simplicity, in Fig. 2 only the control unit 208 is shown,but vehicles of the type shown often include a relativelarge number of control units, e.g. for engine control,gearbox, etc., which is well known to those skilled in the artthe technical field.
    The present invention can thus be implemented in the control unit208, but can also be implemented in whole or in part in one orseveral other control units located at the vehicle.
    Controllers of the type shown are normally arranged to takereceiving sensor signals from different parts of the vehicle, e.g., such asshown in Fig. 2, said pressure sensor 209 and temperature sensors210-212, and also e.g. a motor control unit (not shown). Thecontrol unit generated control signals are normally also dependentboth of signals from other control units and signals fromcomponents. For example, the control unit 208 may control thethe regeneration of the present invention depends oninformation received from the engine control unit, for example, andthe temperature / pressure sensors shown in Fig. 2.
    Furthermore, control units of the type shown are usually providedto emit control signals to various parts and components ofthe vehicle, in the present example for example tothe motor control unit to request / order control ofcombustion engine combustion as below.
    The control is often controlled by programmed instructions. Theseprogrammed instructions typically consist of onecomputer programs, which when executed on a computer orcontrol unit causes the computer / control unit to perform the desired operationcontrol, such as process steps of the present invention.
    The computer program is usually a computer program product 109stored on a digital storage medium 121 (see Figure 1b) such asfor example: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), Flash memory, EEPROM(Electrically Erasable PROM), a hard disk drive, etc., in orin connection with the control unit, and which is executed bythe control unit. By changing the instructions of the computer programcan thus the behavior of the vehicle in a specific situationaflpaSSâS.
    An exemplary controller (controller 208) is shown schematically in FIG.1b, wherein the control unit 208 in turn may comprise acalculation unit 120, which may be substantially any11suitable type of processor or microcomputer, e.g. a circuit fordigital signal processing (Digital Signal Processor, DSP),or a circuit with a predetermined specific function(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 storedprogram code 109 and / or the stored data computing device120 needed to be able to perform calculations.
    The calculation unit 120 is also arranged to store partial orend result of calculations in memory unit 121.
    Furthermore, the control unit 208 is provided with devices 122, 123,124, 125 for receiving and sending input and output, respectivelyoutput signals. These input and output signals can containwaveforms, pulses, or other attributes, which ofthe devices 122, 125 for receiving input signals candetected as information and can be converted into signals,which can be processed by the computing unit 120.
    These signals are then provided to the computing unit 120.
    The devices 123, 124 for transmitting output signals are providedto convert signals obtained from the computing unit 120 forcreation of output signals by e.g. modulate the signals,which can be transferred to other parts of the vehicle's steering systemand / or the component (s) for which the signals are intended.
    Each of the connections to the receiving devicesrespective transmission of input and output signals can be constitutedof one or more of a cable; a data bus, such as a CAN bus(Controller Area Network bus), and MOST bus (Media OrientatedSystems Transport), or any other bus configuration; orof a wireless connection.
    According to the above, regeneration can take place in mainly two different ways.
    On the one hand, regeneration can take place through so-called oxygen (O2) -basedregeneration, also called active regeneration. At the activelOl5l2the regeneration burns the soot load in the particle filter 202normally substantially complete. That is, eat a totalregeneration of the particle filter is obtained, after which the soot content inthe particle filter is essentially 0 grams.
    With active filter systems, fuel is added to the exhaust gases andthis fuel is intended to be oxidized overthe oxidation catalyst 205, which is located upstream ofthe particulate filter 202. When the fuel burns, heat is generated and achemical process mainly according to eq. l is obtained inparticle filter 202:C + and Ö C02 + heat (eq. L)Thus, during active regeneration, carbon plus oxygen are converted tocarbon dioxide plus heat. However, this chemical reaction is strongtemperature dependent, and requires relatively highparticulate filter temperatures to appreciable reaction rateshould occur at all. Typically a minimum is requiredparticle filter temperature of 500 ° C, but preferably shouldthe particle filter temperature be even higher tothe regeneration must take place at the desired speed.
    The reaction according to equation 1 has a high velocity between 550 ° Cand 650 ° C, and increases exponentially with temperature, which doesthat it quickly becomes uncontrollable with increasing temperatures.
    The maximum temperature that can be used at is often limitedactive regeneration of tolerances for the constituentsthe components. For example. often has the particle filter 202design constraints with respect to itmaximum temperature to which they may be exposed. For example, canthe particulate filter 202 and / or its active coating, if anycoating applied, destroyed by, for example, meltingat temperatures above 650 ° C if a lot of soot has accumulated inl0l5l3the particle filter 202, since the structure of the particle filter does notwithstands higher temperatures than that.
    This means that the active regeneration can have onecomponent related maximum allowable temperature that is undesirablelow. At the same time, a very high minimum temperature is requiredto any useful reaction rate at allshould occur.The temperature after the particle filter 202 can also belimited in terms of components due to sensitive componentssitting downstream of the particulate filter 202. For example, canat least one catalyst is placed downstream of the particulate filter202 in certain exhaust gas purification systems. These components can thenneed to be protected against temperatures exceeding a maximumtemperature limit during the regeneration process.
    Thus, it is very important to be able to regulate the temperature inthe particulate filter so that it is close to a desired onesetpoint temperature, where the setpoint temperature is normally inrange 400 ° C to 650 ° C, depending on the presentcomponents in the exhaust stream and of the desiredregeneration strategy, ie passive and / or activeregeneration.
    It is disadvantageous in terms of volume and costarrange the oxidation catalyst 205 so large that it can handleby oxidizing all fuel added to the active onethe regeneration. In practice, therefore, the reaction inthe oxidation catalyst according to:HC + and Ö HC + H 2 O + CO 2 + Heat (eq. 2)The term HC resulting from the reaction here constitutes that amountfuel passing the oxidation catalyst 205 unburned,which is sometimes referred to as the "HC slip". The size of the crowd14unburned fuel depends, among other things, on the exhaust gas flow and the amountadded fuel. If, for example, a driver of the vehicle givesincreased throttle increases the flow and the size of the HC slip changesdepending on the flow change.
    Therefore, the particle filter 202 is often coated with an activematerial to be able to oxidize the fuel that passes throughoxidation catalyst 205 unburned. The active coatingin the particulate filter also improves a passive regeneration inthe particle filter. Because some of the added fuel, itthat is, the HC slip, is first burned in the particulate filteronly then has all the energy in the fuel been converted toheat. Thus, in practice, it is only in a point directlydownstream of the particulate filter for which the temperature is knownthe particulate filter the added fuel results in.
    Furthermore, a normally dimensioned filter system,including oxidation catalyst 205 and particulate filter 202,for a larger motor vehicle, such as a truck or a bus, aconsiderable mass. As a non-limiting example, it can be mentioned thatsuch a filter system for a motor vehicle with an engine volumeabout 9 to 16 liters weigh about 15 to 25 kg. Thisconsiderable mass causes the filter system to become thermally inert,where a considerable amount of energy is needed to increase the temperature1 ° C. This thermal inertia results in a difficult to controlfilter system, because the response time of the filter systemincluding the oxidation catalyst 205 and the particulate filter202 becomes considerable. For example, the response time may be severalminutes at a low exhaust mass flow. In addition, one wouldmeasurement at a point after the particle filter 202 is also not accurateshow the conditions within the particle filter.
    Figure 3a shows examples of temperature profiles belowregeneration, where the above-mentioned problems with previously knownl0l5l5temperature controls are illustrated. Here it corresponds to the thicksolid curve 301 of T @ ¿mC, which is acatalyst inlet temperature for the oxidation catalyst 205and can be measured with a temperature sensor 210 arranged upstreamfrom the oxidation catalyst and in contact with the exhaust gases. Thethe dot-dashed curve 302 corresponds to 7; _mW_w ,, which is onesetpoint for an inlet temperature of the particulate filter 202. Itthin solid curve 303 corresponds to] Q_m, which is ainlet temperature, that is to say a real inlet temperature,for the particle filter 202. Dot curve 304 corresponds to T fl w, whichis the temperature of the particle filter 202.
    Figure 3a clearly shows that the temperature is 75% inthe particle filter 304 varies greatly when the control is performedbased on a substantially constant setpoint for ainput temperature for the particle filter 202, i.e. onecurve 302 for 7% _mW_w, which is substantially constant belowthe regeneration. Here the temperature in the particle filter 304 fluctuatesin an undesirable manner due to the oxidation catalyst 205varying efficiency of fuel combustion, thatthat is, dependent on the HC release. Due to the filter systemthermal inertia are these sharp fluctuations forthe temperature in the particle filter 304 difficult to counteract withpreviously known regulation.
    According to the present invention, the particle filter here has oneinput temperature 7% _mW, which is determined at a point betweenthe oxidation catalyst 205 and the particulate filter 202, byfor example the temperature sensor 211, which is in contact withthe exhaust gases, or by means of a model for the inlet temperature7% * m. A ratio between this input temperature 7% _mWfor the particulate filter 202 and the temperature Iàw forlOl516the particle filter is defined according to the invention. The relationshipis part of a model of the oxidation catalystfuel combustion function. This relationship depends on oneamount of fuel which passes through the oxidation catalyst 205unburned, ie by the HC slip. By utilizingthis condition is then regulated by the input temperature Ykimw forthe particle filter 202 based on the ratio, whereinthe temperature T¿W for the particle filter is kept essentially arounda predetermined target temperature for a defined period of time.
    When the invention is used for regulation, it constitutespredetermined target temperature is typically a suitable oneworking temperature for the regeneration, which is withinrange 400 ° C to 650 ° C, as mentioned above. Thedefined time period here constitutes a time which corresponds to oneactive stage of the regeneration, which constitutes the stage ofregeneration when good soot combustion is obtained. The definedthe time period should have a length so that the desired regenerationcompleted. That is, the time period should be so longthat the resulting soot load after regeneration has onedesired level. Thus, the regulation is performed here so that the temperature% in the particulate filter is kept substantially constant around atarget temperature suitable for good soot combustion during the activethe stage of the regeneration of the particle filter 202.
    Because the defined relationship determines a relationshipbetween the inlet temperature 7% _mW for the particulate filter and forthe actual temperature is 75% in the particulate filter, that is, speaksabout how the particle filter temperature 75 change ifthe inlet temperature 7% _m can be changed, can, by utilizingratio, the temperature 75% in the particle filter indirectlyregulated via the inlet temperature 7; _mW.17By doing so in this way, that is, by utilizingthe ratio that takes into account the HC release, regulatethe temperature T fi w in the particle filter indirectly by regulatingthe inlet temperature Yhimw reduces the problem of the thermalthe inertia of the filter system. This is due to the regulationhere is performed at the inlet temperature Y% _m to the particle filter202, that is, on the temperature afteroxidation catalyst 205. Oxidation catalyst 205 constitutesonly about 25% of the mass of the filter system, why theythe remaining approximately 75% of the pulp which is derived fromthe particle filter 202, when controlling according to the invention, does notcontributes to the thermal inertia. The response time is hereby reducedby essentially 75%. Thus, the supplement is excluded fromthe particulate filter 202 to the thermal inertia throughutilization of the relationship in the regulation, which stronglyreduces regulatory issues.
    In this way, the relationship is utilized in the regulation so thatthe inlet temperature Yhim is regulated so that the temperature is 15% inthe particulate filter can be kept at substantially the same level below itactive stage of the regeneration of the particulate filter. It wantssay, by utilizing the ratio, the temperature can be 15% inthe particle filter is indirectly regulated via the inlet temperatureTmpm, so that a substantially constant temperature T @ W inlthe particle filter is obtained during the active part of the regeneration.
    An example of temperature control in the particulate filter 202according to the invention is illustrated in Figure 3b. Here correspondsas in Figure 3a the thick solid curve 301 of IQJMC,which is a catalyst inlet temperature forthe oxidation catalyst 205. The dot-dashed curve 302corresponds to 7% MW Mr, which is a setpoint for one18inlet temperature for the particulate filter 202. The thin solidcurve 303 corresponds to IQJFF, which is an input temperature,that is, an actual inlet temperature, forthe particle filter 202. The point curve 304 corresponds to Y fi, which isthe temperature of the particulate filter 202.
    As shown in Figure 3b, the temperature Yàw forthe particle filter 304 is kept substantially constant around 600 ° Cduring the active part of the regeneration by regulating the plant insteadinput temperature Ygimw 303 up and down in value. The regulationof the inlet temperature Ykñm 303 is based here on itdefined the relationship and thus takes into accounttemperature 75% in the particulate filter 304 depending on the HCthe slip, which allows the substantially constant temperatureTMW in the particle filter 304 can be produced belowactive phase of regeneration.
    In practice, the setpoint value I¿¿wFjå 303 is continuously calculated forthe inlet temperature based on the predetermined onethe target temperature, ie based on a desired temperatureTMW 304 in the particle filter 202, and from the prevailingcircumstances of the catalyst, which are indicated by the ratio,that is, of the model of the catalystfuel combustion function. A PID controller is then activatedthe target temperature is reached for the particle filter 202, and is workingthen to keep an inlet temperature T; ¿wF, which holdsthe temperature T fl w in the particle filter around the target temperature.
    By, by utilizing the definedratio, take into account the efficiency of the catalyst one caneven and stable temperature is obtained in the particle filter 202throughout the active phase of the regeneration process. Thisis very favorable, because the soot is accumulated in19the particle filter 202 and this is also where the temperature should bebe kept stable for efficient regeneration and foravoid uncontrolled temperature rise.
    According to one embodiment of the present invention, it is definedthe relationship, that is, the model ofthe fuel combustion function of the oxidation catalyst, so thatthe amount of fuel, which passes unburned throughthe oxidation catalyst 205 depends on a mass flow throughthe particulate filter 202 and / or a catalyst inlet temperatureYQJWC for the oxidation catalyst 205. Thereby one is obtainedgood approximation of the HC slip, whereby also an effectiveregulation of the temperature few for the particulate filter canobtained.
    The mass flow through the particle filter 202 can be determined in different waysway. The mass flow can, for example, be determined by onemass flow sensor 214 arranged so that it can measurethe exhaust gas flow, that is to say arranged so that it enterscontact with the flow through the exhaust purification system. As shown inFigure 2, the mass flow sensor 214 may be located in the inletto the internal combustion engine, so that it comes into contact with airwhich is sucked into the internal combustion engine. For vehicles which are anywayequipped with mass flow sensor 214, this embodiment iscost-effective as this value for mass flow can then easilyobtained without further changes in the system.
    The mass flow through the particle filter 202 can also be determined byutilizing an efficiency model for the engine 101, wherethe efficiency model can be based on at least one of oneair pressure and an air temperature for air which is sucked intosaid motor motor 101. This embodiment is advantageous invehicles which are not equipped with mass flow sensors 214.
    Through these embodiments for determining the mass flow canexact values for the mass flow are obtained.
    Furthermore, as above, the relationship betweeninput temperature 7 @ _mW and temperature T @ W forthe particulate filter, that is, the model ofthe fuel combustion function of the oxidation catalyst, by theheat generated when the HC sludge is combusted in the particulate filter202.
    This relationship depends, according to one embodiment ofinvention, of a difference between the temperature Th forthe particulate filter 202 and the catalyst inlet temperature Tfor the oxidation catalyst 205, which is used inregulation to achieve a relatively even andstill temperature 75 for the particle filter below the active onepart of the regeneration.
    The relationship is defined, according to one embodiment, according to:Ämp fi ”= Ew _fb @ W> zmDmJXAT / (ekV ° 3)due to the fact that the temperature increase of the particle filter is dueof the proportion of fuel burned is used, and where Tnp fl, andl75% is the inlet temperature and the temperature forthe particle filter 202; fi z is the mass flow through the particulate filteravg202, which can be determined by mass flow sensor 214 orefficiency model as above; TLJWC isthe catalyst inlet temperature of the oxidation catalyst 205;and fßñWwT; JmC) constitute a function dependent on the mass flow ñ %%and the catalyst inlet temperature TQJWC, which estimates21the proportion of fuel R %% Mm, m that passes unburned throughthe oxidation catalyst.
    In other words, jßñWy7; ¿mC) describes the proportion of fuel Rww fi mjmwhich do not burn up in the catalyst, where the constituentsthe variables are the mass flow fi gæ andFunctions jßñWy7; ¿wC)catalyst inlet temperature 7; ¿mC.can, as will be appreciated by one skilled in the art, have an arbitraryappropriate design, which results in a good estimate ofthe proportion of fuel Rwwümjw that passes through unburnedthe catalyst. For example, the function jß @ w, ÄLDm) can be onecorrelation of measured or estimated values for itunburned proportion of fuel RWwwM¿HC with various measured orestimated values for the mass flow ñgæ andcatalyst inlet temperature 7% ¿mC.
    The function fßhwyïglwc) can also be designed as an equation,which describes the proportion of unburned fuel RWÜMWIHC asdepending on the mass flow fi gæ and the catalyst inlet temperatureIQJMC. The proportion of unburned fuel Rqmwmjm can then, for examplecalculated according to:ä, (ref)Røfïirbränr_HC = fG / i / lavg ° Tin_D0C) = _ e Tííißoc) (eq ° 4)avgwhere k, Z are constants in the function, and where fi z Uçf) is oneavgconstant which constitutes a reference mass flow.
    AT is in equation 3 the difference between the temperature Ib ithe particulate filter and the catalyst inlet temperature Tgjmc forthe oxidation catalyst, that is:lOl522AT = TDPF-T ,, _ DOC. (Eq. 5)The term jßhW @ 7% _Mx) XAT in Equation 3 therefore describesthe relationship between the temperature Y @ W and the inlet temperatureTMim for the particle filter as a difference of a number of degrees.
    By exploiting the relationship, that is, the model forthe fuel combustion function of the oxidation catalyst, according toequation 3, the regulation of the temperature Tbw ithe particulate filter is done indirectly by regulatinginlet temperature 7% _m, resulting in faster response time andthereby achieving faster regulation through reduced thermalinertia. It has been shown that a marked increase inthe accuracy in temperature stability of the temperature TNT atthe particulate filter is obtained by the present invention. In other wordsa suitable temperature TNT in the particle filter can be reached and alsostably maintained thanks to the faster response time.
    As described above, the present invention relatesmainly for regulating the temperature T fl w ithe particle filter. The temperature TàW in the particulate filter is ithis regulation is a substantially fictitious target value, which isit is desirable that the regulation keeps the temperature inthe particle filter around. With the regulation itself, then, it isnot really necessary to determine the actualthe temperature 15% in the particle filter, the important thing is to keepthe temperature T @ W in the particle filter is substantially constant,thereby minimizing the impact of mass inertia. However, it isadvantageous in calibrating this substantially fictitioustarget value to be able to determine the temperature 15% inthe particle filter. According to a further embodiment ofpresent invention, therefore, indicates the relationship, that islOl523say the model of the function of the oxidation catalystthe fuel combustion, that the temperature Iàw in the particulate filterconstitutes an average temperature of the inlet temperature 7% _mW forthe particulate filter 202 and a measured temperature TßW_m fl forthe particulate filter, where the measured temperature T @ W_m¶ is determinedwith the temperature sensor 212 arranged downstream fromthe particulate filter 202 and in contact with the exhaust gases. To take advantagean average temperature is advantageous when different parts ofthe particulate filter may have different temperature, then the temperature inthe different parts of the particulate filter, for example, may be due to hydrocarbonswhich burns upstream in the filter resulting in heatfurther downstream in the filter.
    According to another embodiment of the invention is determinedthe temperature 75% in the particle filter based on a measuredtemperature T¿W_m¶ for the particle filter, where it measuredthe temperature Yhw mn is determined with the temperature sensor 212 arrangeddownstream from the particle filter 202 and in contact withthe exhaust gases. This embodiment has an advantage in that it canimplemented with minimal increased computational complexity.
    It should be noted, which applies generally to the presentdescription and requirements, that the fact that a temperature sensoris arranged "in contact with" the exhaust gases of course caninclude all applicable forms of direct and / or indirectthermal contact / transmission / line between the exhaust gases andthe temperature sensor.
    Figure 4 shows a flow chart of the method according topresent invention. In a first step 401 of the processdefines a ratio between an inlet temperature forthe particulate filter 202 and a temperature of the particulate filter 202.
    According to the present invention, this ratio depends on alOl524amount of fuel passing through the oxidation catalyst 205unburned, ie by the HC slip. The relationship canthus seen as a model of the function of the oxidation catalystregarding fuel combustion.
    In a second step 402 of the method, this is utilizedcondition for regulating the inlet temperature Ykimw forthe particle filter, so that the temperature Ib in the particle filteris kept essentially around a predetermined target temperature below onedefined time period. The regulation is based on that heredefined the relationship. When the invention is applied toregeneration kept the temperature Ib in the particle filtersubstantially constant around a target temperature which is favorablefor efficient regeneration for a corresponding period of timethe active stage of regeneration.
    The present invention also relates to a system for regulatinga temperature of 75% in the particulate filter 202. The system comprisesa defining means, which is arranged to define oneratio between the inlet temperature 7 @ _m forinthe particle filter 202 and said temperature TDPFthe particle filter. This relationship depends, as describedabove, by the HC release, that is, by the amount of fuel thatpasses through the oxidation catalyst 205 unburned. The systemfurther comprising a regulating means, which is arranged toregulate the inlet temperature 7 μm for the particle filter 202based on this ratio between the inlet temperature 7% ñmWand the temperature is 75% in the particle filter, the temperatureget in the particle filter can be kept substantially around onepredetermined target temperature for a defined period of time.l0l5The system is further arranged to comprise means for executionof the various embodiments of the method described aboveaccording to the invention.
    Furthermore, the invention relates to a vehicle according to figure1a, which includes a particle filter 202 and a systemaccording to the invention, wherein the system is arranged to performthe regulation of the temperature in the particulate filter bythe method according to the above-described embodiments ofthe invention.
    As will be appreciated by one skilled in the art, the present may beinvention is utilized in essentially all applications therefuel is added to the exhaust gases and where a desired temperature I @ W ithe particulate filter should be reached and held in the particulate filter 202.
    The model of the oxidation catalystfuel combustion function, that is, the relationship betweeninlet temperature ÄKDH, and temperature 15% for the particle filtercan thus be used in a variety of applications, such as toexamples of rapid heating of components placeddownstream of the particulate filter by means of HC injection,or in desulfurization of oxidation catalyst and / orparticulate filter which is then suitably made at a constant temperaturebetween 400-500 ° C for a certain time.
    The present invention has been exemplified above in connectionto vehicles. However, the invention is also applicable toarbitrary vessels where the exhaust gas purification system as above isapplicable, such as e.g. water or aircraft.
    权利要求:
    Claims (18)
    [1]
    A method for controlling a temperature Tàw in a particulate filter (202), wherein said particulate filter is arranged downstream of an oxidation catalyst (205) in an exhaust gas purification system (200) and wherein said particulate filter has an inlet temperature ÄLMW, which is determined at a point between said oxidation catalyst (205) and said particle filter (202), characterized in that - a relationship between said inlet temperature ÄKDH. for said particulate filter (202) and said temperature 75% in said particulate filter (202) is defined, said ratio depending on an amount of fuel passing through said oxidation catalyst unburned, and included in a model for a fuel consumption function of said oxidation catalyst (205), and - said inlet temperature fl mp fl. for said particle filter (202) is controlled, based on said ratio, so that said temperature TNT in said particle filter (202) is kept substantially around a predetermined target temperature for a defined period of time.
    [2]
    The method of claim 1, wherein said amount of fuel passing unburned through said oxidation catalyst (205) depends on at least one of: - a mass flow through said particulate filter (202); and - a catalyst input temperature TQJWC for said oxidation catalyst (205).
    [3]
    A method according to claim 2, wherein said mass flow is determined by means of a mass flow sensor (214) which is arranged to come into contact with air which is sucked into an engine connected to said exhaust gas purification system (200).
    [4]
    The method of claim 2, wherein said mass flow is determined by an efficiency model for an engine connected to said exhaust gas purification system (200).
    [5]
    A method according to claim 4, wherein said efficiency model is based on at least one of an air pressure and an air temperature for air which is sucked into said engine.
    [6]
    A process according to any one of claims 1-5, wherein at least one of said inlet temperature fi nß för, for said particle filter (202) and a catalyst inlet temperature TQJWC for said oxidation catalyst (205) is determined by at least one temperature sensor (210, 211), which is in contact with exhaust gases in said exhaust gas purification system (200).
    [7]
    A process according to any one of claims 1-6, wherein said ratio depends on an amount of heat generated when said amount of fuel passing through said oxidation catalyst (205) unburned is combusted in said particulate filter (202).
    [8]
    A process according to any one of claims 1-7, wherein said ratio is due to a difference between said temperature T fl w in said particle filter (202) and an inlet temperature 7k_mw for said oxidation catalyst.
    [9]
    A method according to any one of claims 1-8, wherein said ratio is defined as: YÉÄDPF: TDP _f (mavg> jninfpoc) xATf where l0 l5 28 28 ÄKDH, is said input temperature of said particle filter (202); Th is said temperature in said particle filter (202); - fi z is a mass flow through said particulate filter (202); avg TmDm¿ is an input temperature for the oxidation catalyst (205); - jß @%, ÄkDmJ is a function dependent on the mass flow fi gæ and the catalyst inlet temperature TQJWC, which estimates the proportion of fuel RWm%, HC that passes unburned through the oxidation catalyst; and - AT is the difference between said temperature Tbw in said particle filter (202) and an inlet temperature of said oxidation catalyst T% JwC.
    [10]
    lO. A method according to any one of claims 1-7, wherein a measured temperature Tbwimn in said particle filter (202) is determined by means of a temperature sensor (212) at a point downstream of said particle filter (202).
    [11]
    ll. The method of claim 10, wherein said ratio indicates that said temperature T @ W in said particle filter (202) is an average temperature of said inlet temperature 7% _mw for said particle filter (202) and said measured temperature T @ W_m fl for said particle filter (202). 10 15 20 25 29
    [12]
    A method according to any one of claims 1-11, wherein said control is used in regenerating said particle filter (202).
    [13]
    The method of claim 12, wherein said predetermined target temperature is in the range of 400 ° C to 650 ° C.
    [14]
    A method according to any one of claims 12-13, wherein said defined time period constitutes an active stage of said regeneration, said time period having a length which ensures that said regeneration is completed.
    [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 belonging to any of the group comprising: ROM (Read-Only Memory), PROM (Programmable ROM), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically EPROM) and hard disk drive.
    [17]
    A system for controlling a temperature TNT in a particulate filter (202), wherein said particulate filter is arranged downstream of an oxidation catalyst (205) in an exhaust gas purification system (200) and wherein said particulate filter has an inlet temperature, wherein the system comprises temperature means arranged to determine said inlet temperature T mymw at a point between said oxidation catalyst (205) and said particulate filter (202), characterized by - defining means, arranged to define a relationship between said inlet temperature Ämßmw for said particle filter (202) and said temperature T said particulate filter (202), said ratio depending on an amount of fuel passing through said oxidation catalyst unburned, and included in a model for a fuel consumption function of said oxidation catalyst (205), and - control means, arranged to control said inlet temperature fl mpm, for particulate filter (202) based on said ratio, so that t said temperature Tßw in said particle filter (202) is maintained substantially around a predetermined target temperature for a defined period of time.
    [18]
    Vehicle (100), characterized in that said vehicle (100) comprises: - a particulate filter (202); and - a system for controlling said temperature Y fl w in said particle filter (202) according to claim 17.
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    同族专利:
    公开号 | 公开日
    SE536168C2|2013-06-11|
    SE1050893A1|2012-03-01|
    SE536169C2|2013-06-11|
    WO2012030280A1|2012-03-08|
    EP2612002B1|2016-10-12|
    EP2612002A4|2014-03-26|
    EP2612002A1|2013-07-10|
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    JP4288985B2|2003-03-31|2009-07-01|株式会社デンソー|Exhaust gas purification device for internal combustion engine|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE1050893A|SE536169C2|2010-08-31|2010-08-31|Procedure and systems for exhaust gas purification|
    SE1150763A|SE536168C2|2010-08-31|2011-08-24|Procedure and systems for exhaust gas purification|SE1150763A| SE536168C2|2010-08-31|2011-08-24|Procedure and systems for exhaust gas purification|
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