• 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:
    A method and a system for determining and utilizing a pressure in an exhaust line connected to an internal combustion engine are presented. A first gas sensor is arranged to provide a first gauge yl corresponding to the first concentration of a blank, said first gas sensor being pressure dependent and arranged in a first position upstream of a post-treatment device in said exhaust line. A second gas sensor is arranged to provide a second measurement yz corresponding to a second concentration of said blank, said second gas sensor being arranged in a second position downstream of said post-treatment device. According to the present invention, an estimation of at least two characteristics is performed comprising a first pressure sensitivity a1 for said first gas sensor and a first flow dependence for a first pressure EQ at said first position. Based on at least said first pressure sensitivity a1, on said first flow dependence and on said first yl and second yz dimensional value, said first pressure HJ is determined which is then used. Fig. 2
    公开号:SE1350106A1
    申请号:SE1350106
    申请日:2013-01-31
    公开日:2014-08-01
    发明作者:Björn Westerberg；Ola Stenlåås
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    l0l5a reducing agent in the form of urea or ammonia intothe exhaust gases upstream of the catalyst. When injecting urea intothe exhaust gases are formed ammonia and it is this ammonia that constitutesthe reducing agent which contributes to the catalyticthe conversion in the SCR catalyst. The ammonia accumulates in thethe catalyst by adsorption on active sites in the catalyst,whereby nitrogen oxides present in the exhaust gases are converted to NÛXnitrogen and water when these in the catalyst are brought into contact withthis accumulated ammonia on the active sites inthe catalyst.
    When using an SCR catalyst in combination withring of reducing agent in the form of urea or ammonia is itimportant to control the injection of the reducing agent so that adesired conversion of the actual exhaust gas is obtained withoutexcessive amounts of unused ammonia accompany the exhaust gasesout of the catalyst and thereby released to the environment. Theis previously known to in a system for controllingthe injection of reducing agents utilize calculation valuesfrom a calculation model which, taking into account the expectedthe reactions in the catalyst under the prevailing operating conditions,continuously determines current conditions in the catalyst.
    There are also previously known methods for measuring pressurein finishing systems, as the procedure described inFR2893979.
    Brief description of the inventionOne of the input values that is often used in onecalculation model for controlling the injection ofreducing agent is the concentration of nitrogen oxides NOX inthe exhaust gases upstream of the catalyst. This concentration candetermined by means of an upstream catalyst locatedNÛX sensor. A conventional NÛX sensor is pressure sensitive andthe measurement signals from the sensor must be corrected for the currentthe pressure around the sensor to give correct values of measuredNOX concentration.
    The pressure in that part of the exhaust line upstream of the SCR catalystwhere the NOX sensor is located varies depending on the prevailingoperating conditions and prevailing pressure drop across the SCR catalystand pressure drops across other exhaust aftertreatment units that arelocated between the NOX sensor and the exhaust outlet. One way toTo determine this pressure is to measure this using apressure transmitter. However, such a supplementary pressure sensor entailsadditional costs that it is desirable to avoid. Thecurrent pressure can alternatively be determined using acalculation model which depends on prevailing operating conditions. Onesuch a calculation model, however, is associated with sources of error such asover time can become relatively large *To solve this, it has been proposed in FR2893979 that apressure dependence of a first oxygen sensor located in a firstposition in the exhaust line upstreamthe finishing device and a pressure dependence of a secondoxygen sensor located in a second position in the exhaust linedownstream of the finishing device shall be used todetermine a pressure difference between the first and secondthe position. The first and second sensors may be connectedto a control unit. According to this proposed solution isthe concentrations of oxygen are identical in the first and secondthe position on certain special occasions, for example at lowexhaust flows after starting the engine.
    Because the oxygen concentrations at certain specificoccasions are assumed to be identical in the first and secondthe position is performed on such a special occasion according toFR2893979 an initial initialization which comprises alOl5restoration of difference values that have been produced for themtwo sensors. After this initialization can, based onthe pressure dependencies of the two sensors and based on oneassumption that the other sensor is exposed to atmosphericpressure plus a pressure drop depending on the other sensorlocation in relation to the exhaust line outlet, the pressure inthe first position is calculated based on the two measured valuesfor the oxygen concentrations provided by the formerand the other gas sensor. Thus, the pressure at it canthe first position is determined without an additional pressure sensorneed to be installed in the exhaust line at the firstthe position.
    However, the solution described in FR2893979 gives only a relativerough determination, that is, an inaccurate determination ofthe pressure. The initialization, which according to FR2893979 is required tothe procedure must be applicable, can according to FR2893979 onlyperformed on certain special occasions and assumes thatthe oxygen concentrations in the first and second positions areas big. Such opportunities can, for example, be given at lowexhaust flows in the exhaust line or during deceleration.
    The solution described in FR2893979 provides only one possibility todetermine a single parameter on which a difference between itthe measured values of the first and the second gas sensor may depend. According toFR2893979 can thus not two or more parameters thataffects this difference is determined. The solution can, for exampledetermine a ratio between the sensitivity of the two gas sensors.
    Alternatively, a ratio between the two sensors can be constantdeviation is determined. FR2893979 further presupposes a givenpressure sensitivity of the gas sensors and a given flow dependencefor the pressure at the position of the sensors, which makes the solutioncan only provide a relatively rough and notreliable determination of pressure.lOl5It is thus an object of the present invention thatprovide a determination of pressure in the exhaust line,which is accurate and reliable, and where the determinationdoes not require an initial initialization. There is also oneneed for a determination of the pressure, which does not presupposethat the other gas sensor is always exposed to pressurecorresponding to atmospheric pressure plus a well-definedsensor placement dependent pressure loss.
    This object is achieved by the above-mentioned method according tothe characterizing part of claim 1. The object is also achievedof the above-mentioned system according to the characterizing part ofclaim 26. The object is also achieved by the abovecomputer programs and computer software products.
    According to the present invention, at least two are estimatedcharacteristics including. These at least twocharacteristic properties include a first pressure sensitivityal for the first gas sensor at a first position and afirst flow dependent for a first pressure fi_ at this firstposition, which are thus estimated. The first press RLthen determined based on at least this estimated firstpressure sensitivity al, on the estimated first flow dependence,and on the first yl and second yz measured values for a concentrationfor a substance at the first and second gas sensors, respectively. Thedetermined first pressure H_ is then used, for example in avehicle.
    Thus, according to the present invention, the first is estimatedthe pressure sensitivity al, which allows the determination of itfirst pressure H according to the present invention can be usedon essentially all types of gas sensors, as the estimatetells how the sensors depend on the pressure. This isa great advantage compared to previously known solutions, whichlOl5assumes that the pressure sensitivities of the sensors are known. Sensorspressure sensitivity may vary with time and after downtime,which means that the previously known solutions either cannotis used or gives poor accuracy in older sensorsand / or in many operational cases.
    Since the present invention estimates the firstthe pressure sensitivity al and the first flow dependence thereoffirst pressure H_at the first sensor knowledge is obtained aboutthese parameters, which can be used to determinethe first pressure H, According to one embodiment, it is also estimatedthe second pressure sensitivity az and the second flow dependence forthe second pressure Get at the second sensor, whereby knowledgeif the individual characteristics of the other donor are obtained,which can be used to determine the second pressureIQ. The knowledge of the other donor's individual characteristics canalso used to increase the accuracy of determiningthe first pressure P2 if the second sensor is pressure sensitive andis positioned so that the pressure varies. So they are estimatedindividual characteristics of the first and / or secondsensors, which are used to increase the accuracy ofthe determination of the first Fä and / or second PE pressure.
    In this way, a weakness identified by the inventors inthe prior art solutions to increase the accuracy ofpresent invention.
    By estimating the individual characteristics of the formerand / or other donors may also be the limiting initialsthe initialization steps of prior art solutions are avoided.
    Because the previously known solutions lack knowledge about theseindividual characteristics so they must ensure that the systemis in a position where these solutions provide acceptableresults.lOl5The present invention can, due to the fact that it estimates andutilizes the pressure sensitivity and flow dependence estimate itfirst Fä and / or second PE pressure at essentially alloperating cases and for essentially all types of sensors, andfor different aging for these sensors. Thus provideda very accurate determination of the first.I¶ and / orsecond P5 pressure, which can be performed substantially continuouslyif desired, or then values for the first.I fl and / or secondIE printing is needed by other systems in, for example, a vehicle.
    This enables the present invention to be utilized generallyand is not dependent on special and relatively rareexisting operational cases.
    Because a relationship between pressure and flow in the exhaust linedetermined by the estimate of the pressure sensitivity andthe flow dependence of the present invention is thus obtainedthe ability to determine the pressure very preciselyeach position in the exhaust line without having a specificmeasured value for the pressure in these positions. Presentinvention does not presuppose that the other sensor experiencesatmospheric pressure plus a well-defined sensor placement dependencepressure loss, making the invention generally applicable ina large variety of positions in exhaust pipes.
    In addition, the present invention can be implemented with onelow addition in complexity, especially since alreadyexisting gas sensors are used in determiningthe pressure.
    Brief list of figuresThe invention will be further elucidated below with reference tothe accompanying drawings, in which like reference numeralsused for equal parts, and in which:Figure 1 shows an engine and exhaust purification system,lOl5Figure 2 shows a flow chart of the present invention,andFigure 3 shows a control unit.
    Description of preferred embodimentsAs mentioned above are today's motor vehicles as well as other devicesand vehicles including internal combustion engines, such asfor example, ships and aircraft, usually equipped with aafter-treatment device arranged for exhaust gas purificationemitted by the engine. This document describes the inventionexemplified in a motor vehicle, but those skilled in the art will recognize thatthe invention can also be applied to substantially all othersdevices and craft including internal combustion engines.
    Figure 1 schematically shows an engine and exhaust purification systemI, which is provided with an internal combustion engine 2 and oneexhaust line 3. Exhaust gases which leave the combustion engine 2 pipesin an exhaust line 3 in the form of exhaust flows 21, 22, 23 ithe various parts of the exhaust line and exit into the environment viaan exhaust outlet 30. In the exhaust line 3 is oneexhaust after-treatment device 4 arranged.
    The exhaust after-treatment device 4 can consist of an individualexhaust aftertreatment unit or of a set of twoor several connected in series and / or connected in parallelexhaust aftertreatment units, where respectivelyexhaust after-treatment unit, for example, consists of a catalystor a particulate filter. In the illustrated examplethe finishing device 4 comprises aoxidation catalyst DOC (Diesel Oxidation Catalyst) 5, aparticulate filter DPF (Diesel Particle Filter) 6 and aproduction catalyst 7, for example of the SCR type (SCR = SelectiveCatalytic Reduction), arranged in series with each other withlOl5the particle filter DPF 6 located between the oxidation catalystDOC 5 and the reduction catalyst 7. However, as mentionedabove do not include the finishing device 4 eachof the oxidation catalyst DOC 5, the particulate filter DPF 6 and theproduction catalyst 7, but may in various embodiments includeone or more of an oxidation catalyst, a particulate filterand a reduction catalyst. Finishing device 4may also include an ammonia abrasive catalyst (ASC), whicheliminates an excess of ammonia.
    The present invention can be used to determine onepressure in an exhaust line 3 connected to an internal combustion engine2. As described above, the first gas sensor is llarranged to provide a first measured value yg correspondinga first concentration of a substance in a first position 3a inthe exhaust line 3 upstream of a finishing device 4 inthe exhaust line. The finishing device 4 may comprise aor more of an oxidation catalyst DOC 5, aparticulate filter DPF 6, a reduction catalyst 7, for examplean SCR, or any other applicablefinishing device. The first gas sensor ll ispressure dependent as mentioned above.
    A second gas sensor 12 is arranged to provide a secondmeasured value yz corresponding to a second concentration of the substancealso measured by the first gas sensor ll. The second gas sensor l2is arranged in a second position 3b downstreamthe finishing device 4.
    The procedure for determining and applying the pressure inthe exhaust line is described below using the flow chart infigure 2.l0l5l0In a first step 20l of the method, an estimation of one is performedfirst pressure sensitivity a1 for the first gas sensor ll. Onefirst flow dependent for a first pressure H_at the firstposition 3a is also estimated. Thus performed in the first step20l an estimate of two characteristic properties, whichcomprises the first pressure sensitivity a1 and the firstflow dependence.
    In a second step 202 of the method, the first is determinedthe pressure Get at the first position 3a based on at leastthe first pressure sensitivity al, on the first flow dependenceand on the first yl and second yz measured values, where the first yland the second yz measured values are provided by the first llrespectively the second l2 gas sensor. This determination is describedmore in detail below.
    In a third step 203 of the method, the determination is usedfirst pressure E, According to one embodiment, it is useddetermined first press Get to correct the firstthe measured value yl provided by the first sensor ll,whereby a more accurate measurement value is obtained. According to aembodiment, the determined first pressure H_for is usedto determine an amount of soot in the particulate filter DPF 6, where itdetermined amount of soot can, for example, be used to determinewhen a regeneration of the particle filter DPF is to be performed.
    According to one embodiment, the determined first is usedpressure to correct other pressure dependencies as wellmeasurement signals, for example measurement signals for both nitrogen oxides NOXand oxygen 02 provided by the first sensor 11, sinceboth of these measured values are pressure sensitive and need to be corrected.
    The process according to the invention can be carried out continuouslyduring a normal operation of the internal combustion engine 2, that islOl5llfor example, while a vehicle is being driven. At continuousestimation, for example, a Kalman filter can be used forthe estimate. According to one embodiment, the estimation is made morerobust by estimating the utilization of the Kalman filterin a first step the estimation is performed quickly for the moresignificant parameters and in subsequent steps are performedslower for other parameters, which is described furtherbelow.
    The method according to the invention takes into account thatthe differences in measured value between the first ll and the second 12the sensor can be due to a number of different things. This means thatseveral parameters may need to be estimated. Some of these have greatimpact on the sensors, ie are more significant,while others have less impact. For example, hasthe pressure sensitivity al and the flow dependence of the first sensorll great impact, while the pressure sensitivity az andthe flow dependence of the second sensor l2 has less effecton the sensors.
    By dividing the estimate into two steps, first they can do the mostthe significant parameters are determined in the first step,after which the less significant parameters are determined in itsecond step. Fast and slow estimation refers to howquickly the estimate converges, that is, how fast theyoptimal parameter values are achieved in the estimation. Practicallythis means that fewer measured values are required beforethe estimate converges for a quick estimate, but that itfast estimation at the same time becomes more sensitive to noise.
    The process of the present invention can also be preceded bya collection of data during normal operation ofthe internal combustion engine 2, on which the estimation is performed based onthese data were collected through a regression analysis. According to a12embodiment, the estimation here is made more robust bythe estimate in a first step collects an appropriate smallernumber of samples of measured values and perform the regression analysis onthese, after which a suitably larger number of samples of measured valuescollected, which are then analyzed in regression analysis.
    According to one embodiment, estimated coefficients are saved whenthe engine shuts off. When the engine is then restarted canthe estimates are started again by continuing from the last onessaved the coefficient values. In this way a more efficient one is obtainedestimation which more quickly results in correct values,since the estimated coefficients are not expected to changesignificantly while the engine is off. So can the pressuredetermined with essentially the same accuracy as before the engineshut down.
    According to one embodiment of the present invention, it is estimatedalso a second pressure sensitivity az for the second gas sensor 12 ithe second position 3b, and a second flow dependent for onesecond press P5 at the second position 3b. Then determinedthe second pressure get based, except on the firstthe pressure sensitivity al, on the first flow dependence and on itfirst yl and second yz measured value, also on this secondpressure sensitivity az for the second gas sensor 12 and on the secondthe flow dependence of the second pressure PE at the secondposition 3b. In this way, both the first is determinedthe pressure Fä and the other pressure PE. It established othersthe pressure may be used according to one embodiment to correctthe second measured value yz provided by the second gas sensor12, thereby providing a more accurate measurement value.
    The present invention utilizes that gas sensors 11,12, whichfor example, the content of nitrogen oxides measures NÛX, oxygen 02, nitrogen ÅQ,l0l5l3carbon dioxide C02, or water H20, are generally pressure sensitive.
    This allows measurement values provided by these sensors,in addition to the content of the saturated substance, also depends onthe total pressure in the gas in which the substance is contained. To obtain itthe correct value of the content of the substance therefore needs the measured valuecorrected with respect to the total gas pressure. A typicalrelationship between a measured value and the correct one, that iscorrected, the content of the substance can be described with the followingequation:yfy-Kïf ”)“ + 1} fwhere y is the measurement signal and 3% is the corrected measurement value,(eq. l)which corresponds to the correct content of the substance. P is the gastotal pressure, P5 is the ambient air pressure, and a sensorpressure sensitivity.
    Sensors generally have a certain accuracy that even canchange as they age. This means that over time they reproducethe measured quantity with a certain deviation. There isat least two types of deviations. One type of deviation isdepending on the size of the measurement signal, ie the deviationis proportional to the measurement signal, and another type ofdeviation is independent of the size of the measurement signal, that isthat the deviation is constant. The relationship between the correctedthe correct measured value and the uncorrected measured value of the sensor candescribed with the equation:xC == k-x-kd, (eq. 2)where x is the uncorrected measured value of the sensor, xc the correctedcorrect measurement value, k is the correction factor for the sensorproportional deviation 1 / k and d is the correction factor forthe constant deviation of the sensor -d. In this document has thus14the correction d for the sensor and the constant deviation of the sensorsame value, but with opposite character id, because the correctiond must correct for the constant deviation -d.
    According to one embodiment of the present invention comprisesprocedure an estimate of at least one furthercharacteristic of one or more of the first ll andthe other 12 sensors. This at least one morecharacteristic includes the proportional error 1 / kfor the first ll and the second 12, respectively, the gas sensor and / or thethe constant deviation -d for the first ll and the second, respectively12 gas sensor. The determination of one or more of the firstthe pressure IQ and the second pressure Fä are then performed based,except for the first al and / or second az pressure sensitivity,on the first and / or flow dependence, and on the first yland the second yz measured value, even on the at least one furthercharacteristic, making a more accuratedetermining the first pressure [Q and / or the secondthe pressure EQ is obtained.
    According to one embodiment of the present invention, each depends onand one of the first presses IQ at the first position 3aand the second pressure P5 at the second position of aexhaust flow rate U in the exhaust line 3 with a linear termelf and with a square term azvz. Exhaust line pressure 3depends on the ambient air pressure as well as onthe flow resistance in the exhaust system. The flow resistancedepends on the degree to which the flow is laminar respectivelyturbulent. The flow resistance also depends on changes inthe cross-sectional area of the exhaust system in the direction of flow. When alleffects are weighed together, the pressure in each position inthe exhaust system is described by the equation:P = P0 + a1-v + a2-v2, (eq. 3)where P is the pressure in the current position in the exhaust system, Fß isambient air pressure, v is the mean velocity of the exhaust gas flow inthe cross section of the flow in the current position and al and az arecoefficients for the linear and quadratic dependence, respectivelyof the flow rate in the current position.
    According to one embodiment of the present invention, each depends onand one of the first pressures get at the first position 3aand the second pressure P5 at the second position of onemass flow ñ in the exhaust line 3 with a linear term b fl ñ and witha square term bynz, where the dependence on the mass flow fi lkandue to a temperature T of the exhaust gases passing throughexhaust line 3.
    Because the cross-sectional area usually varies along the exhaust systemflow direction, it is advantageous to use volume orthe mass flow in the equation for the flow dependence of the pressure (equation3). The flow rate relates to the volume flow throughthe cross-sectional area and the volume flow to the mass flow throughthe density according to the following equation:v =% = f = ---, (eq.4)where q is the volume flow, A is the cross-sectional area, 1h is the mass flow, pis the density, P is the pressure, E1 is the average molecular weight of the exhaust gases, Ris the general gas constant and T is the temperature. Printeddepending on the mass flow can thus be expressed as:P = P0 + b1-m + b2-m2, (eq. 5)where bl and bz are coefficients for the linear andquadratic dependence on mass flow. These coefficients arel0l5l6temperature dependence through density temperature dependence.
    Since the first coefficient bl describesthe laminar part of the flow resistor also has onetemperature dependence from viscosity temperature dependence, withan exponent between 0.7 and 0.75, b1 ~ [TQÄT®7¶, depending onthe composition of the gas. Overall, this means that the firstthe coefficient bl depends on the temperature with the exponent l.7-1.75,Mf {TLÄT47¶, and that the second coefficient bz depends onthe temperature with the exponent 2, b2 ~ T2.
    If the gas sensor's pressure sensitivity a, the correction k for itsproportional 1 / k deviation and the correction d for itsconstant deviation -, as well as the pressure flow dependence are includedin the same equation is obtained:PoP0 + b1'Tñ + b2'm2yC = k-y - [(-1) a + 1] + d (eq. 6)If the quotient of the pressure is divided by the ambient air pressure H, iboth numerator and denominator and the equation simplified are obtainedthe expression:C1'Tfl + C2'7fl2 J di I1 + c -m + c -mz (ekX / v '7)1 zM; == k-y- [1-awhere cl and CZ are the coefficients bl and bz divided byambient air pressure HWAccording to an embodiment of the invention, the firstthe measured value yl measured by the first gas sensor ll and thesecond measured value yz measured by the second gas sensor l2 relatedto a substance or compound, where a concentration of the substanceor the compound on passage through the finishing device4 remains essentially unchanged. When this is the case canthe determination of the pressure in the exhaust line is based on a17assumption that a first corrected measured value nn,corresponding to this first measured value y1, and a second correctedmeasured value yü, corresponding to this second measured value y2, is equallarge.
    For two gas sensors, the first gas sensor ll placed in itfirst position 3a and the second gas sensor 12 located inthe second position Bb in the exhaust system, which measures a substancewhich are unaffected by the components of the exhaust system, they must thereforecorrected the measured values of the two gas sensors ll, 12 beequal to each other, that is:yc, l: yc, 2 (eq- 8)Which, using equation 7, is equivalent to:C21Tfl + C227fl2k1y1 [1-a ähdl fl fzyzh-a] + d2 (eq. 9)1 1 + C117ñ + C12Tfl2 2 1 + C21Tfl + C22 fi l2Where the first position 3a corresponds to index 1 and itthe second position 3b corresponds to index 2, which forthe coefficients C1 and C2 correspond to the first digit of the index.
    Equation 9 can be rewritten according to:1+ 1- '+ 1-' 2kl 1 l (a1) C11 "1 (a1) C127" _ + dl1 + -cllrh + -c121h21 + _ a2) C21m + _ a2) C22m21 + -czlrh + -c221ñ2+ d2= kzyzl(eq. 10)A subtraction of the correction dl for the first constantthe deviation -dl from both terms and multiplication of both termswith each denominator gives:18k1Y1 [1 + '(1 _'a1) C11Ü1' + (1'_a1) C12Tñ2] (1 + "C217Ü '+' C227ñ2)I kzyzil "i" (1 _ az fi z fl ñ "i" (1 _ az fi zzmzkl "i" 511m "i" C12m2)(Eq. 11)The equation can be rewritten so that each page is expressed asa polynomial of the mass flow rh according to:k1Y1 {1 "|" [(1 _ a1) c11 "i" 0211751 "|" [(1 _ a1) (C12 "i" 011521) "i" 02217112+ "(1 _ a1) (C11C22 +" C12C21) 7Ü3 + '(1 _ a1) C12C227Ü4}= k2y2 {1 + [(1 - a2) c21 + cllhñ + [(1 - a2) (c22 + c21c11) + clzhñz+ "(1 _'a2) (C21C12 '+' C22C11) 7h3 *" (1 _'a2) C22C1z7Ü4}+ - (dz -d1) {1 + - (C11 + -c21) 1ñ + - (C12 + -C22 + -c11c21) 1h2+ "(C11C22 +" C12C21) 7h3 + "C12C227h4}(6kV. 12)From Equation 12, the gas sensors 11, 12 can thenpressure dependence / pressure sensitivity al, az, correction factors kl, kzfor proportional deviation 1 / kl, 1 / kz and corrections dl, dzfor constant deviation -dl, -dz and respective pressureflow dependence is estimated. Thus, the first pressure can be H_andthe second pressure F is determined based on equation 12.
    According to an embodiment of the invention, the size ofthe pressure dependence of the respective gas sensors be relatively equal, alwcy.Also the correction factors kl, kz for each gas sensorproportional deviation can be expected according to the embodimentbe relatively equal, k1 == k2. This allows the terms withthe product of the respective food value and the powers 3 and 4 ofthe mass flow ñ1 basically takes each other out. Sincethe flow resistance is greater for the one located upstreamthe gas sensor ll in the first position 3a meant that all19coefficients C11- for the upstream gas sensor ll aregreater than the corresponding coefficient C fi for that of the otherposition 3b downstream of the gas sensor 12.assumptions according to the invention, the estimation according tothe invention.
    These simplifications reduce the estimation problem to:kY2 I ÉJHÜ i "[(1 _ a1) C11 i" C211m "i" [(1 _ C-'1XC12 "i" C11C21) "i" C221m2}_ Y2 {[(1 _ a2) C21 "i" C111m "i" [(1 _ az) (C22 "i" C21C11) "i" C121m2}((12 _ (11).. 2IT11 "i" (C11 "i" C21) m "i" (C12 "i" C22 "i" C11C21) m 1(eq.
    Equation 13 can be written as:3/2 = 3/1 15.10 "i" ßnm "i" ß12m2] _ 3/2 [ß21m "i" ßzzmz] _ 11/0 "i" 1/1711 "i" Yzmzi(eq.
    Where respectively the coefficient ßij and V1- are expressions of theoriginal coefficients k1, k2, a1, a2, C11, C12, C21, C22,and d2 according to:C10 = å; (eq-ß11 =: i [(1 _ a1) C11 "i" C211; (SKV -ß12 = 1: -: [(1 _ 011) (C12 i "C11C21)" i "C221; (SKV -ß21 = (1 _ a2) C21 "i" C117 (ekV -ß22 = (1 _ C-'2) (C22 "i" C21C11) "i" C12 (GKV -V0: (112 _ d fl kií (SKV-2Through these13))16)17)18)19))21)l0yl = (dz-dl)%; and (Eq. 22)_ C12 + C22 + C11Cz1V2 _ (dz _ d fl i-M (eq. 23)According to one embodiment of the invention, onlythe magnitude of the first measured value yl of said first pressurelä, that is, only the first gas sensor ll in itfirst position 3a is pressure dependent. About the other gas sensor12 in the second downstream position 3b is independentfrom the print all terms containing Qi, Q2 and respectively are deleted1-az, which simplifies the expression considerably.
    According to an embodiment of the invention, the size ofthe first measured value yl and the second measured value yz offthe first pressure P2 and the second pressure IQ, respectivelysay that both the first ll and the second l2 are the gas sensorpressure dependent.
    According to an embodiment of the invention, the estimation is performed inat least two steps then both the first ll and the second 12the gas sensor is pressure dependent. Then it is estimated in the first step. . k .. ..the coefficients fy a1, cn and Cu with the assumed values for2the coefficients az, Qn, CH, dl and dz respectively. In the second stepnew values are estimated for these coefficients where the coefficientsestimated in the first step are utilized as known. Whenadditional new values were estimated for the coefficients aftersecond step can these coefficients estimated in the secondthe step is utilized in a subsequent additional firststep. In other words, in the first step they are most valuedsignificant coefficients, which have the greatest impact onthe connection. In the second step, the remainder is estimatedcoefficients.l0l52lAccording to one embodiment of the invention, the estimation is paused bythe pressure sensitivity and flow dependence of the formerthe gas sensor 11 in the first position 3a and for the secondthe gas sensor 12 in the second position 3b if the first yl andother yz measured values are expected to be different sizes, that isas the measured gas concentration can be expected to be different atthe first position 3a of the upstream firstthe gas sensor ll and at the second position 3b for itdownstream placed the second gas sensor 12. That the estimatepausas in this application means that the estimation is terminated forto be resumed later, that the estimate is temporarily postponedwaiting mode, or that the estimate in some other waysuspended. The pause of the estimate makes thatinaccurate estimates are avoided, which increases accuracy as wellthe robustness of the method of the present invention.
    However, the determination of the first P2 and / or second PEthe pressure still continues when the first yl and second yzthe measured values are expected to be different sizes, if the determination thenbased on already estimated values of flow dependence.
    The first yl and second yz measured values are expected to differsignificantly ate in case of operation when the measured gas concentrationaffected by reactions in the components of the exhaust system between themboth the location of the gas sensors, for example at a fastchange of requested engine torque and / or speed, that issay in the event of a rapid change in power take-off from the engine. Pädue to the volume of the exhaust system between the first ll andsecond l2 sensor, there is a certain time lag between itthat the exhaust gases passing the first sensor ll until itthese pass the second sensor l2. This time depends onthe volume and velocity of the gas which in turn depends onmass flow, pressure and temperature. Because these arerelatively well known yeast it to compensate forlOl522the time lag, but usually not quite perfect. Atstationary operating cases and in case of slow changes this givesdoes not give rise to any major deviation. At fastchanges, however, this can lead to significant deviations.
    Therefore, the estimation should be paused according to the inventionprocedure in that situation.
    The first yl and second yz measured values are also expected to differsignificantly when a regeneration of the particle filter DPF 6 is in progress.
    During regeneration, hydrocarbon which is oxidized inthe oxidation catalyst DOC 5, which affects the oxygen content sothat this decreases, and affects the carbon dioxide and water levelsso that both of these increase. Therefore, the estimate should be according to aembodiment of the invention is temporarily paused in connectionto regeneration, for example by pausing the estimationwhile the regeneration is in progress and then resumes whenthe regeneration is completed, whereby new parameter values candetermined as soon as possible after regeneration. Thecalculated the pressure at the first position 3a upstreamplaced first gas sensor ll can be expected to be somethingoverestimated / elevated some time after a regenerationimplemented, until new values for the coefficients forthe flow dependence of the pressure has been estimated.
    According to one embodiment of the present invention is basedthe estimate of an assumption that the former correctedthe measured value y fl, corresponding to the first measured value yl, differsfrom the second corrected measured value yæ, corresponding to the secondmeasured value yz. The difference between these corrected measured valuesdepends here on the amount of the saturated substance consumed betweenthe first 3a and second 3b position. A small change ofthe measured gas concentration of the substance between the gas sensorsfirst 3a and second 3b positions occur relatively often. INthe oxidation catalyst DOC 5 consumes oxygen at the same time aslOl523carbon dioxide and water are formed. The same reactions occur inthe particulate filter DPF 6, however to a much lesser extent. INThe SCR catalyst 7 consumes oxygen. The extent of thesechanges can be determined from models for respectivecomponent of the exhaust system. To improve the accuracy ofthe estimation is thus compensated according to this embodiment ofthe invention the measured value for it in the second position 3bdownstream placed the second gas sensor 12 for this changeof the gas concentration of the substance.
    The procedure for determining and applying a pressure inan exhaust line according to the present invention may additionallyimplemented in a computer program, which when executed ina computer causes the computer to perform the method. The computer programis usually part of a computer program product 303, wherethe computer program product includes a suitable digitalstorage medium on which the computer program is stored. Mentionedcomputer readable media consists of a suitable memory, 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.
    According to one aspect of the present invention, there is providedsystems for determining and using a pressure in aexhaust line connected to an internal combustion engine. The systemincludes the first l1 and second l2 described abovethe gas sensors. The system also includes an estimation unit l3larranged to estimate at least two characteristic propertiesincluding, wherein the estimation includes an estimation of afirst pressure sensitivity a1 for the first gas sensor ll and aestimation of a first flow dependence for a first pressure P1at the first position 3a. The system further comprises adetermining unit 132, which is arranged to determine itfirst pressure H_based at least on the first24the pressure sensitivity al, on the first flow dependence and on thefirst yl and second yz measured values. The system also includes autilization unit 133 arranged to utilize the determinedfirst pressure E,Figure 3 schematically shows a control unit 300, which constitutes oneschematic description of the control unit 13 in figure 1, which isconnected to the first 11 and second 12 gas sensor.
    The control unit 300 comprises a calculation unit 301, which canconsists of essentially any suitable type of processor ormicrocomputer, e.g. a digital signal processing circuit(Digital Signal Processor, DSP), or a circuit with apredetermined specific function (Application SpecificIntegrated Circuit, ASIC). The calculation unit 301 is connectedwith a memory unit 302 arranged in the control unit 300, whichprovides the computing unit 301 e.g. the storedthe program code and / or the stored data calculation unit 301need to be able to perform calculations. The calculation unit301 is also arranged to store partial or final results ofcalculations in the memory unit 302.
    Furthermore, the control unit 300 is provided with devices 311, 312,313, 314 for receiving and sending input and output, respectivelyoutput signals, for example measurement signals from the first 11 andother 12 gas sensor. These input and output signals cancontain waveforms, pulses, or other attributes, which ofthe devices 311, 313 for receiving input signals candetected as information and can be converted into signals such ascan be processed by the computing unit 301. These signalsthen provided by the computing unit 301. The devices 312,314 for sending calculation results from the calculation unit301 to output signals for transmission to other parts ofthe vehicle's control system and / or the component (s) for whichthe signals are intended, for example, for other parts of the systeml0l5engine and exhaust system, or to other parts offor example a vehicle.
    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 bus), or any other bus configuration;or by a wireless connection.
    One skilled in the art will appreciate that the above-mentioned computer may be comprised ofthe calculation unit 301 and that the above-mentioned memory canconsists of the memory unit 302.
    In general, steering systems in modern vehicles 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. Vehicles of the type shown thus includeoften significantly more control units than shown in Figures 1 and3, which is well known to those skilled in the art.
    The present invention is in the embodiment shownimplemented in the control unit 300. However, the invention can alsoimplemented in whole or in part in one or more others atthe vehicle already existing control units or in any forthe present invention dedicated controller.
    Those skilled in the art will also appreciate that the above system may be modified accordinglythe various embodiments of the method according to the invention.
    In addition, the invention relates to a motor vehicle, for example onetruck or bus, and other devices and craftincluding internal combustion engines, such as a ship or a26aircraft, including at least one determination systemof exhaust back pressure according to the invention.
    The present invention is not limited to the abovedescribed embodiments of the invention without reference to andincludes all embodiments within the appended independentthe scope of protection of the requirements.
    权利要求:
    Claims (26)
    [1]
    A method for determining and utilizing a pressure in an exhaust line connected to an internal combustion engine (2), wherein a first gas sensor (II) is arranged to provide a first measured value yl corresponding to a first concentration of a substance, wherein said first gas sensor (II) ) is pressure dependent and is arranged in a first position (3a) upstream of a finishing device (4) in said exhaust line; and a second gas sensor (12) is arranged to provide a second measured value yz corresponding to a second concentration of said substance, said second gas sensor (12) being arranged in a second position (3b) downstream of said finishing device (4); characterized by - an estimate of at least two characteristic properties comprising a first pressure sensitivity a1 for said first gas sensor (11) and a first flow dependence for a first pressure obtained at said first position (3a); a determination of said first pressure H_based at least on said first pressure sensitivity a1, on said first flow dependence and on said first y1 and second y2 measured value; and - an utilization of said first pressure Rp
    [2]
    The method of claim 1, wherein - said estimating said at least two characteristics comprises an estimation of at least one further characteristic of one or more of said first (l1) and said second (l2) sensors; and - said determining said first pressure H_ is performed based on said first pressure sensitivity a1, on said first flow dependence, on said first yl and second yz measured value, and on said at least one further characteristic; wherein said further characteristic property comprises one or more in the group of: - a proportional error 1 / k for said first (11) and second (12) gas sensor, respectively; and - a constant deviation -d for said first (l1) and second (l2) gas sensors, respectively.
    [3]
    A method according to any one of claims 1-2, wherein: - said estimating said at least two characteristic properties comprises an estimation of a second pressure sensitivity az for said second gas sensor (12) and an estimation of a second flow dependence for a second pressure EQ at said second position (3b); a determination of said second pressure may be performed based on said first pressure sensitivity a1, on said first flow dependence, on said first y1 and second y2 measured value, on said second pressure sensitivity az and on said second flow dependence; and - said second pressure P5 is used.
    [4]
    The method of claim 3, wherein - said estimating said at least two characteristics comprises an estimation of at least one additional characteristic of one or more of said first (l1) and said second (l2) sensors; and - said determining said second pressure P5 at said second position (3b) is performed based on said first pressure sensitivity a1, on said first flow dependence, on said first yl and second yz measured value, on said second pressure sensitivity az, on said second flow dependence, and on said at least one further characteristic; wherein said further characteristic 10 comprises one or more in the group of: - a proportional error 1 / k for said first (11) and second (12) gas sensor, respectively; and - a constant deviation -d for said first (11) and second (12) gas sensors, respectively.
    [5]
    A method according to any one of claims 1-4, wherein said determining of said first and / or second PE pressures is performed continuously during a normal operation of said internal combustion engine (2).
    [6]
    A method according to any one of claims 1-4, wherein said determining of said first Fä and / or second Fä pressures is preceded by a collection of data during a normal operation of said internal combustion engine (2) and is performed based on said collected data.
    [7]
    A method according to any one of claims 1-6, wherein each of said first pressures EQ and a second pressure PE at said second position (3b) is dependent on an exhaust gas flow rate U in said exhaust line (3) with a linear term eleven and with a square term azvz.
    [8]
    A method according to claim 7, wherein said dependence on said exhaust gas flow rate v depends on a temperature T for said exhaust gases.
    [9]
    A method according to any one of claims 1-6, wherein each of said first pressures Fä and a second pressure P2 at said second position (3b) is dependent on a mass flow fi1 in said exhaust line (3) with a linear term b fl ñ and with a square term bynz. 10 15 20 25 30
    [10]
    A method according to claim 9, wherein said dependence on said mass flow ïh depends on a temperature T for said exhaust gases.
    [11]
    A method according to any one of claims 1-10, wherein said first measured value yl and said second measured value yz are related to a substance or a compound, wherein a concentration of said substance or said compound on passage through said finishing device (4) remains substantially unchanged .
    [12]
    A method according to any one of claims 1-11, wherein said determining said first P2 and / or second P5 pressures is based on an assumption that a first corrected measured value ya, corresponding to said first measured value ylf and a second corrected measured value yæ, corresponding to said other measured value y2, are equal.
    [13]
    A method according to claim 12, wherein a relationship between said first corrected measured value y fl and said second corrected measured value yæ is defined according to: c m + c m2 c m + c m2 ._ klyl _ a1 + dl: kzyz _ az + dz, where l + C11m + C12m 1 + C21m + C22m - kl, k2 is a correction for a proportional error 1 / kl, 1 / k2 for said first (11) and second (12) gas sensors, respectively; yl, yz are said first and second measured values; al, az is a pressure sensitivity mentioned for first (11) and second (12) gas sensors, respectively; -ïñ is a mass flow of said exhaust gases; ql, Cu, ch, CH are coefficients for a linear and quadratic dependence of the mass flow divided by ambient air pressure for said first (11) and second (12) gas sensors, respectively; and dd, dz is a correction for a constant deviation -dl, -dz for said first (11) and second (12) gas sensors, respectively.
    [14]
    A method according to any one of claims 1-11, wherein said determining of said first Fa and / or second PE pressure is based on an assumption that a first corrected measured value ya, corresponding to said first measured value y1, differs from a second corrected measured value ya , corresponding to said second measured value yg, where the difference depends on an amount of said substance consumed between said first (3a) and second (3b) position.
    [15]
    A process according to any one of claims 1-14, wherein said finishing device (4) comprises one or more in the group of: - an oxidation catalyst (5); - a particle filter (6); - a reduction catalyst (7); and - an ammonia abrasive catalyst.
    [16]
    A method according to any one of claims 1-15, wherein said determining said first pressure H_ utilizes that a magnitude of said first measured value y1 is affected by said first pressure H
    [17]
    A method according to any one of claims 1-15, wherein said determining said first Fa and / or second PE presses utilizes that a magnitude of said first measured value y1 and said second measured value yz, respectively, is affected by said first pressure H_respectively said second pressure RP
    [18]
    A method according to any one of claims 1-17, wherein said first measured value y1 and said second measured value yz are related to a substance in the group of: - oxygen - O 2; - nitrogen gas AQ; - carbon dioxide CO2; and - water H 2 O.
    [19]
    A method according to any one of claims 1-18, wherein said estimation of at least two characteristic properties is paused when said first yl and second yz measured value are expected to be different magnitudes.
    [20]
    A method according to claim 18, wherein said first yl and second yz measured values are expected to differ significantly when one or more occur in the group of: - a rapid change exists for a requested engine torque and / or speed; and - a regeneration of a particle filter (6) in said finishing device (4) is in progress.
    [21]
    A method according to any one of claims 1-20, wherein said determined first pressure H_ is used to correct said first measured value yl and / or other pressure-dependent measured values.
    [22]
    A method according to any one of claims 1-21, wherein a determined second pressure IQ at said second position (3b) is used to correct said second measured value yz and / or other pressure-dependent measured values.
    [23]
    A method according to any one of claims 1-22, wherein said determined first pressure H is used to determine an amount of soot in a particle filter (6) in said finishing device (4). l0 15 20 25 30 33
    [24]
    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 of claims 1-23.
    [25]
    A computer program product comprising a computer readable medium and a computer program according to claim 24, wherein said computer program is included in said computer readable medium.
    [26]
    A system for determining and utilizing a pressure in an exhaust line connected to an internal combustion engine (2), wherein: - a first gas sensor (II) is arranged to provide a first measured value yq corresponding to a first concentration of a substance, wherein said first gas sensor (11) is pressure dependent and is arranged in a first position (3a) upstream of a finishing device (4) in said exhaust line; and - a second gas sensor (12) is arranged to provide a second measured value yz corresponding to a second concentration of said substance, said second gas sensor (12) being arranged in a second position (3b) downstream of said finishing device (4); characterized by - an estimation unit (131) arranged to estimate at least two characteristic properties comprising a first pressure sensitivity a1 for said first gas sensor (11) and a first flow dependence for a first pressure E_ at said first position (3a); a determining unit (132) arranged to determine said first pressure H and - a utilization unit (133) arranged to utilize said first pressure E,
    类似技术:
    公开号 | 公开日 | 专利标题
    SE1350106A1|2014-08-01|Determination and utilization of exhaust backpressure
    CN110735696B|2021-09-21|System, method and apparatus for estimating soot loading during no load or low load
    US8635030B2|2014-01-21|Method for the determination of a NOx concentration value upstream of a SCR catalyst in a diesel engine
    US9038369B2|2015-05-26|Systems and methods for aftertreatment system diagnostics
    EP2851531A1|2015-03-25|Exhaust gas control apparatus and control method for exhaust gas control apparatus
    US8806928B2|2014-08-19|Catalyst deterioration detection apparatus and catalyst deterioration detection method for internal combustion engine
    SE1050891A1|2012-03-01|Procedure and systems for exhaust gas purification
    GB2538735A|2016-11-30|Control apparatus and method
    CN104343512A|2015-02-11|Method and apparatus for determining efficiency of exhaust gas purification device
    US9068495B2|2015-06-30|Oxidation catalyst/hydrocarbon injector testing system
    SE540265C2|2018-05-15|Process and system for supplying additives to an exhaust stream
    SE534479C2|2011-09-06|Estimation of a deviation for at least one model variable of a catalyst model
    US10519841B2|2019-12-31|Method and system for monitoring of a physical quantity related to a particulate mass in at least one exhaust pipe
    US10724418B2|2020-07-28|Method and a system for determining a flow resistance across a particulate filter
    US20190345865A1|2019-11-14|A system and a method for determining a cause for impaired performance of a catalytic configuration
    SE538625C2|2016-10-04|System and method for diagnosing a sensor of an exhaust gas cleaning system
    CN101802358A|2010-08-11|Method for detecting the minimum opening time of a reducing agent feed device in an exhaust gas aftertreatment system comprising an scr catalyst
    KR20200054321A|2020-05-19|Method for operating exhaust gas aftertreatment system of diesel engine and exhaust gas aftertreatment system
    US20210222597A1|2021-07-22|Method and system determining a reference value in regard of exhaust emissions
    SE1350167A1|2014-08-14|Device and method for troubleshooting an SCR system
    SE536774C2|2014-07-29|Method and system for determining a sensor function for a PM sensor by means of pressure comparisons
    SE538317C2|2016-05-10|System and method for performance control of a DOC unit exhaust gas purification system
    JP2011085091A|2011-04-28|Filter downstream pressure loss calculation device
    SE1150792A1|2013-03-01|Procedure for an SCR system and an SCR system
    JP2017008758A|2017-01-12|Filter state estimation device of internal combustion engine for vehicle
    同族专利:
    公开号 | 公开日
    SE539380C2|2017-08-29|
    WO2014120070A1|2014-08-07|
    DE112014000399T5|2015-09-24|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE102004043365A1|2004-09-08|2006-03-09|Robert Bosch Gmbh|Exhaust gas back pressure determining method for internal combustion engine, involves determining exhaust gas back pressure from influencing variables that are interrelated with engine operation on basis of model|
    JP5482446B2|2010-05-25|2014-05-07|いすゞ自動車株式会社|SCR system|
    ITBO20110213A1|2011-04-20|2012-10-21|Magneti Marelli Spa|METHOD OF UPDATING A PRESSURE LAW THAT PROVIDES THE DISCHARGE PRESSURE ACCORDING TO THE DISCHARGE GAS FLOW IN AN INTERNAL COMBUSTION ENGINE|DE102014010623B4|2014-07-21|2016-05-12|Iav Gmbh Ingenieurgesellschaft Auto Und Verkehr|Method for determining the pressure in the exhaust system of an internal combustion engine|
    DE102014018601A1|2014-12-17|2016-06-23|Iav Gmbh Ingenieurgesellschaft Auto Und Verkehr|Method for monitoring the effectiveness of an exhaust gas treatment apparatus|
    GB2538735B|2015-05-26|2019-06-12|Jaguar Land Rover Ltd|Variable sensitivity pressure differential detection in a vehicle aftertreatment system|
    US9644548B2|2015-10-02|2017-05-09|GM Global Technology Operations LLC|Exhaust system pressure estimation systems and methods|
    US9657670B2|2015-10-02|2017-05-23|GM Global Technology Operations LLC|Exhaust system temperature estimation systems and methods|
    US11092336B2|2018-09-18|2021-08-17|Denso Wave Incorporated|Method for estimating water content, and estimation device|
    法律状态:
    2021-09-28| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    SE1350106A|SE539380C2|2013-01-31|2013-01-31|Determination and utilization of exhaust backpressure|SE1350106A| SE539380C2|2013-01-31|2013-01-31|Determination and utilization of exhaust backpressure|
    PCT/SE2014/050106| WO2014120070A1|2013-01-31|2014-01-28|Determination and utilization of exhaust gas back-pressure|
    DE112014000399.9T| DE112014000399T5|2013-01-31|2014-01-28|Determination and use of exhaust back pressure|
    [返回顶部]