• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a method in the SCR system of a motor vehicle (100; 110), comprising a feeding device (230) for feeding from container (205) reducing agent to a dosing unit (250) pre-supplying said reducing agent to an exhaust duct of the vehicle (100). ; 110) .dosing by means of a pressure (Pr) below which reducing agent is reduced. The method comprises the step of controlling the dosing unit (250). The invention also relates to a computer program product comprising program code (P) for a computer (200; 210) for implementing a method according to the invention. The invention also relates to SCR systems and a motor vehicle (100) equipped with the SCR system. Figure 2 for publication
    公开号:SE1151192A1
    申请号:SE1151192
    申请日:2011-12-14
    公开日:2013-06-15
    发明作者:Andreas Liljestrand；Per Bremberg
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    1015202530There are various ways to reduce emissions from motor vehicles. One way is todifferent ways to regulate a prevailing temperature of the exhaust stream to optimizea degree of conversion of an SCR catalyst in the vehicle.
    SUMMARY OF THE INVENTIONThere is a constant need to improve the current SCR system to reducethe amount of unwanted emissions from an internal combustion engine.
    An object of the present invention is to provide a novel andadvantageous procedure for improving the performance of an SCR system.
    Another object of the invention is to provide a new and advantageousSCR system and a new and advantageous computer program to improveperformance of an SCR system.
    An object of the present invention is to provide a novel andadvantageous procedure to reduce the amount of unwanted emissions froman internal combustion engine.
    Another object of the invention is to provide an alternativeprocedure for an SCR system and an alternative computer program for an SCRsystem and an alternative SCR system.
    These objects are achieved by a method in SCR systems of a motor vehicleaccording to claim 1.
    According to one aspect of the invention, there is provided a method of SCR systemsof a motor vehicle, comprising a feeding device for from acontainer feed reducing agent to a dosage unit for delivery ofsaid reducing agent to an exhaust duct of the vehicle. The procedure1015202530comprises the step of controlling the dosing of the dosing unit by means of a pressure belowwhich reducing agent is dosed.
    This enables an exemplary dosing of the reduction medium of an SCRsystem. A relatively high working pressure of said reduction mediumgenerally produces smaller droplets that can be more easily captured in oneexhaust flow from the vehicle's engine. A relatively low working pressure of the saidreduction media can generally produce larger droplets as with ahigher kinetic energy is not affected by the exhaust flow in the same way as lessdrops. In some operating cases it is advantageous with smaller drops, e.g. at lowexhaust gas temperature where a small drop can be evaporated relatively quickly inthe exhaust gas flow. In another operating case, where a high thermal energy is stored inthe exhaust system, it is advantageous to have larger droplets which can then be directed towardsfor example a surface of the exhaust system. In this case, an improvement is achievedperformance of the SCR system.
    By varying according to the invention the working pressure Pr in a suitable manner,depending on e.g. inherent characteristics of the dosage unit, one cancone angle of the dosed reductant is advantageously changed in the desired manner. lanalogy to the above, this can be used to optimize the hit image and / ormixture of reducing medium and exhaust gases. By changing a working pressurewith the SCR system can speedaffected. This entails substantially identical benefits as described above.also of the reducing agent dropletsBy controlling the dosage of the dosing unit by the pressure below whichtheretodroplet size distribution is affected. This can have a big impact depending onreduction medium can be dosed thus an associatedtype of dosing equipment used.
    The method may include the step of controlling the pressure below which reduction mediumdosed by controlling a speed of said feeding device.
    In this case, an accurate procedure is provided in an SCR system according to a1015202530aspect of the invention. Said pump speed can be controlled with very highaccuracy and thus a working pressure of the SCR system can also be controlledwith a high accuracy. In this case, a robust procedure can be achieveda reliable way.
    The method may include the step of controlling the pressure by changing onethrottling in a reducing line return line from the dosing unitto said container. In this case, a careful procedure is achieved at oneSCR system according to an aspect of the invention. Said throttling can be changedwith very high accuracy and thus a working pressure of the SCRthe system is also controlled with a high accuracy. In this case, a robustprocedure is accomplished in a reliable manner.
    The method may include the step of controlling the pressure by changingdosage unit configuration. In this case, a careful is achievedmethod in an SCR system according to an aspect of the invention. Mentionedconfiguration can be changed with very high accuracy and thus one canworking pressure of the SCR system is also controlled with a high accuracy. Herebya robust process can be achieved in a reliable manner.
    The method may include the step of controlling the dosage of the dosage unitby means of the pressure on the basis of a prevailing temperature of an exhaust gas flow froman engine and / or a prevailing mass flow of exhaust gases from an engine. Herebyan improved performance of the SCR system can be achieved. Herebya versatile procedure is also provided in an SCR system, sincealternative designs are possible. A prevailing mass flow of the exhaust gases canis calculated by a control unit of the vehicle, or alternatively measured by amass flow sensor. Because temperature sensors are relatively inexpensivea cost-effective procedure is also provided according to an aspect ofthe invention.1015202530The method may include the step of controlling the dosage of the dosage unitby means of the pressure on the basis of a prevailing temperature of a surface in an exhaust pipeat the vehicle. In this case, the intended temperature sensor must therefore be installed atthe vehicle in an appropriate manner if one is not already installed.
    The method may include the step of controlling the dosage of the dosage unitby means of the pressure on the basis of a prevailing temperature of an ambient airat the vehicle. In this case, the intended temperature sensor must therefore be installed atthe vehicle in an appropriate manner if one is not already installed.
    The method may include the step of controlling the dosage of the dosage unitby means of the pressure on the basis of previous operating cases of the vehicle. Here is onecontrol unit of the vehicle arranged to by means of calculations according to a storedmodel control the dosing unit dosing by means of the pressure in an appropriate manner.
    The method may include the step of controlling the dosage of the dosage unitby the pressure and a cycle frequency of the dosage. This is achieveda procedure in an SCR system with improved performance. Bycombine control of the dosage unit dosage by the pressure ofthe reductant during dosing and by means of changes of a prevailingcycle frequency of the SCR system can provide an optimized spray image of the saiddosed reducing agents are provided. In this case, the amount may be undesirableemissions from the vehicle's engine are advantageously reduced.
    The process may include the step of varying the pressure of the reductant within onerange of [5, 15] bar. According to one embodiment, the method may comprise the stepto vary the pressure of the reductant within a range of [7, 13] bar. According to oneexecution, the method may include the step of varying the pressure of the reductantwithin a range of [10, 50] bar. According to one embodiment, the procedure mayincluding the step of varying the pressure of the reductant within a range of [100,300] bar. According to one embodiment, the method may include the step of varyingthe pressure of the reductant within any suitable range. Hereby1015202530a robust procedure is achieved where a work interval is defined in advancethus eliminating the risk of unwanted spray image caused by too low orhigh working pressure. This ensures a reliable and dependable procedurein an SCR system according to an aspect of the present invention.
    The process may include the step of varying the pressure of the reductant steplesslyin said control of the dosage of the dosing unit. This is achieveda method in which a desired spray image of said reductant can be seta well-defined way. In this case, a method of one is advantageously providedSCR system where a desired mixture of exhaust gases and reducing agents canset with a very high accuracy.
    The method may further comprise the step of varying the pressure of the reductant indiscrete steps in said control of the dosage unit dosage. Herebyprovides a method of an SCR system where relatively simpleprogramming routines are required. By providing control ofdosing of the dosing unit where discrete adjustable steps of the working pressure areexisting, a speed of the feeding device can be controlled againstpredetermined setpoints, which has the advantage of being less computationally difficultdata processing is required.
    The method may include the step of changing a cycle frequency of the dosagesteplessly. In this case, a method is provided in which a desired spray image ofHerebyadvantageously, a method of an SCR system where a desired one is providedsaid reductant can be set in a well-defined manner.mixture of exhaust gases and reducing agents can be set with a very highaccuracy.
    The method may comprise the step of changing a cycle frequency of the dosage indiscrete steps in said control of the dosage unit dosage. Throughto provide control of the dosage unit dosage there discreteadjustable steps of the cycle frequency are present can a speed of1015202530the feeding device is controlled against predetermined setpoints, which entailsthe advantage that less computationally heavy data processing is required.
    The method may include the step of controlling the dosage of the dosage unitby the pressure of the reductant and a cycle frequency of the dosing onbasis of a prevailing exhaust gas temperature and / or a prevailing exhaust gas mass flowof exhaust gases from an engine of the motor vehicle.
    It should be noted that the procedure may include any of the abovesaid feature inappropriate combination.
    The procedure is easy to implement in existing motor vehicles. Software atan SCR system according to the invention can be installed in a control unit ofthe vehicle in the manufacture of the same. A buyer of the vehicle can thus getpossibility to select the function of the procedure as an option. Alternatively cansoftware including program code to perform the innovative procedure atan SCR system. In this case, the software can be loaded into a memory in the control unit.
    Implementation of the innovative procedure is thus cost-effective, inespecially since no additional sensors or components are neededinstalled in the vehicle. Required hardware is already available inthe vehicle. The invention thus provides a cost-effective solution to thethe above problems.
    Software comprising program code for an SCR system according to the inventioncan be easily updated or replaced. Furthermore, different parts of the software such asincludes the program code exchanged independently. This modularconfiguration is advantageous from a maintenance perspective.
    According to one aspect of the invention, an SCR system is provided in onemotor vehicle, comprising a feeding device for moving from a containerfeeding reducing agent to a dosage unit for supplying saidreducing agent to an exhaust duct of the vehicle. The SCR system includes1015202530means for controlling the dosing of the dosing unit by means of a pressure below whichreducing agents are dosed.
    The SCR system may further comprise means for controlling the pressure by controlof a speed of said feeding device.
    The SCR system may include means for controlling the pressure by changing onethrottling in a reducing agent return line from the dosing unitto said container.
    The SCR system may include means for controlling the pressure by changingdosage unit configuration.
    The SCR system may include means for controlling the dosage of the dosage unitby means of the pressure on the basis of a prevailing temperature of an exhaust gas flow froman engine and / or a prevailing mass flow of exhaust gases from an engine.
    The SCR system may further comprise means for controlling the dosing unitdosing by means of the pressure and a cycle frequency of the dosing.
    The SCR system may further include means for varying the pressure ofthe reductant within a range of [5, 15] bar.
    The SCR system may include means for varying the pressure of the reductantsteplessly in said control of the dosage of the dosing unit.
    The SCR system may include means for varying the pressure of the reductant indiscrete steps in said control of the dosage unit dosage.
    The SCR system may include means for changing a cycle frequency ofthe dosing steplessly or in discrete steps in said control ofdosing unit dosage.1015202530The SCR system may include means for controlling the dosage of the dosage unitby the pressure of the reductant and a cycle frequency of the dosing onbasis of a prevailing exhaust gas temperature and / or a prevailing exhaust mass flow rateof exhaust gases from an engine of the motor vehicle.
    The above objects are also achieved with a motor vehicle comprising the SCRthe system. The motor vehicle can be a truck, bus or car.
    According to one aspect of the invention, there is provided a computer program for an SCRsystem, wherein said computer program comprises program code stored on one, by onecomputer readable, medium for causing an electronic controller or anothercomputer connected to the electronic control unit to perform the steps according to somethingof claims 1-11.
    According to one aspect of the invention, there is provided a computer program for an SCRsystem, wherein said computer program includes program code stored on amedium to cause an electronic controller or another computer connectedto the electronic control unit to perform the steps according to any ofclaims 1-11.
    According to one aspect of the invention, there is provided a computer software productcomprising a program code stored on a computer readable medium forperforming the method steps according to any one of claims 1-11, when saidcomputer programs run on an electronic controller or other computer connectedto the electronic control unit.
    Additional objects, advantages and novel features of the present inventionthe invention will be apparent to those skilled in the art from the following details, as wellvia the practice of the invention. While the invention is described below,it will be apparent that the invention is not limited to those specifically describedthe details. Those who have access to the teachings herein will recognize101520253010additional applications, modifications and incorporations within othersareas which are within the scope of the invention.SUMMARY DESCRIPTION OF THE DRAWINGSFor a more complete understanding of the present invention and furtherpurposes and benefits thereof, reference is now made to the following detaileddescription to be read together with the accompanying drawings there equallyreference numerals refer to equal parts in the various figures, and in which:Figure 1 schematically illustrates a vehicle, according to an embodiment ofthe invention;Figure 2 schematically illustrates a subsystem of the vehicle shown in Figure 1, according toan embodiment of the invention;Figure 3a schematically illustrates a flow chart of a method, according to aembodiment of the invention;Figure 3b schematically illustrates in further detail a flow chart over onemethod, according to an embodiment of the invention; andillustrates a computer,Figure 4 schematically according to an embodiment ofthe invention.
    DETAILED DESCRIPTION OF THE FIGURESReferring to Figure 1, a side view of a vehicle 100 is shownThe exemplary vehicle 100 consists of a tractor 110 and a trailer 112.
    The vehicle can be a heavy vehicle, such as a truck or a bus. The vehiclecan alternatively be a car.
    It should be noted that the invention is suitable for application in aarbitrary SCR system and is not sold limited to SCR system atmotor vehicle. The innovative procedure and the innovative SCR systemaccording to one aspect of the invention is well suited for other platforms such as101520253011includes an SCR system other than motor vehicles, such as e.g. watercraft.
    The watercraft can be of any kind, such as e.g. motorboats,ships, ferries or ships.
    The innovative procedure and the innovative SCR system according to one aspectof the invention is also well suited for e.g. systems includingindustrial engines and / or motorized industrial robots.
    The innovative procedure and the innovative SCR system according to one aspectof the invention is also well suited for different types of power plants, such as e.g.an electric power plant comprising a diesel generator.
    The innovative procedure and the innovative SCR system are well suitedfor any motor system including an engine and an SCR system,such as e.g. at a locomotive or other platform.
    The innovative procedure and the innovative SCR system are well suitedfor an arbitrary system that includes a NOX generator and an SCRsystem.
    Here, the term "link" refers to a communication link that may be onephysical wire, such as an opto-electronic communications wire, or anon-physical wiring, such as a wireless connection, such as a radio ormicrowave link.
    Here, the term "lead" refers to a passage for holding and transportinga fluid, such as e.g. a reductant in liquid form. The wire can be a tube ofarbitrary dimension. The management can consist of an arbitrary, appropriatematerials, such as e.g. plastic, rubber or metal.
    Here, the terms "reductant" or "reducing agent" refer to an agent whichis used to react with certain emissions in an SCR system. These101520253012"Reductant""Reducing agent" is used synonymously herein. Said reductant is according to oneemissions can e.g. be NOX gas. The terms andexecution so-called AdB | ue. Of course, other types of reductants can be used.
    Here, AdB | ue is given as an example of a reductant but one skilled in the art will recognizethat the innovative procedure and the innovative device can be realizedfor other types of reductants, with the necessary appropriate adjustments incontrol algorithms in accordance with the innovative procedure.
    Here, the term cycle frequency refers to a frequency defined bythe number of dosing intervals, also called dosing cycles, per second. Theshould be noted, however, that at least one active dosage of reducing agentof the dosing unit can be performed during a dosing cycle.
    Here, the term pressure of the reductant refers to a pressure below which saidreductant is metered from a dosing unit of the innovative SCR system.
    The pressure below which said reductant is dosed and the working pressure Pr are usedhere synonymous.
    Referring to Figure 2, a subsystem 299 of the vehicle 100 is shown.
    The subsystem 299 is arranged in the tractor 110. The subsystem 299 may constitute apart of an SCR system. According to this example, the subsystem 299 consists of acontainer 205 arranged to hold a reductant. The container 205 isarranged to contain a suitable amount of reductant and is further arrangedto be able to top up when needed.
    A first line 271 is arranged to lead the reductant to a pump 230 fromthe container 205. The pump 230 may be any suitable pump. The pump230 may be a diaphragm pump comprising at least one filter. The pump230 may be arranged to be driven by means of an electric motor (not shown). The pump is230 arranged to inflate the reductant from the container 205 via the firstline 271 and via a second line 272 supply said reductant to adosing unit 250. Dosing unit 250 includes an electrically controlled101520253013dosing device, by means of which a flow of to the exhaust system is addedreductant can be controlled. The dosing unit 250 may include an electrically controlleddosing valve, by means of which a flow of reductant added to the exhaust systemcan be controlled. The pump 230 is arranged to pressurize the reductant in the otherthe line 272. The dosing unit 250 is provided with a throttling unit,which can also be called throttle valve, against which said pressure ofthe reductant can be built up in subsystem 299. This pressure is referred to hereinas the working pressure Pr of the SCR system.
    The dosing unit 250 is arranged to supply said reductant to a100.the dosing unit 250 arranged to supply a suitable amount in a controlled mannerexhaust system (not shown) of the vehicle More specificallyreductant to an exhaust system of the vehicle 100. According to this embodiment, aSCR catalyst (not shown) arranged downstream of a position of the exhaust systemwhere supply of the reductant is effected. The amount of reductant added inthe exhaust system is intended to be used in the SCR catalyst to reducethe amount of unwanted emissions.
    The dosing unit 250 may be arranged at an exhaust pipe (not shown) which isarranged to conduct exhaust gases from an internal combustion engine (not shown) of the vehicle100 to the SCR catalyst and further to an environment of the vehicle.
    A third conduit 273 is provided between the metering unit 250and the container 205. The third conduit 273 is arranged to return onecertain amount of the reductant fed to the metering valve 250 tocontainer 205. With this configuration, advantageous cooling is providedof the dosing unit 250. In this way, the dosing unit 250 is cooled bya flow of the reductant as it is pumped through the dosing unit 250from the pump 230 to the container 205.
    A first control unit 200 is arranged for communication with a pressure sensor220 via a link 221. The pressure sensor 220 is arranged to detect a prevailing one101520253014press Pr at the reductant where the sensor is mounted. According to this embodiment isthe pressure sensor 220 provided at the second line 272 for measuringthe working pressure Pr of the reductant downstream of the pump 230. According to anotherIn this embodiment, the pressure sensor 220 is arranged in the dosing unit 250 for measuringthe working pressure Pr of the reductant downstream of the pump 230. The pressure sensor 220is arranged to continuously send signals to the first via the link 221the control unit 200 including information about a prevailing pressure Pr atthe reductant.
    The first control unit 200 is arranged for communication with the pump 230via a link 231. The first control unit 200 is arranged to control the operation ofthe pump 230. According to one example, the first control unit 200 is arranged tocontrol the pump 230 by means of an electric motor. The first control unit 200 isarranged to influence the working pressure Pr in the second line 272. This cantake place in various appropriate ways.
    According to one example, the first control unit 200 is arranged to change onecurrent speed RPM of the pump 230. In this case, the pressure Pr can be changeddesirable way. By increasing the RPM speed of the pump 230 canthe working pressure Pr is increased. By lowering the RPM speed of the pump 230 canworking pressure Pr is lowered.
    According to another example, the first control unit 200 may be arranged toaffect the pressure Pr by controlling a change of a stroke of a pistonor a diaphragm of the pump 230. By actuating an internalconfiguration or internal geometry of the pump 230, the pressure Pr can be variedeven while maintaining a substantially constant RPM speed ofthe pump 230. In this case, the influence of the pressure Pr can be effected byfor example change the stroke of pistons or diaphragms of pump 230.
    The first control unit 200 is arranged for communication with onetemperature sensor 240 via a link 241. The temperature sensor 240 is arranged101520253015to detect a prevailing temperature T of an exhaust stream from the vehicleengine. According to one example, the temperature sensor 240 is arranged directlydownstream of the vehicle engine and upstream of a dosing unit 250.
    The temperature sensor 240 is arranged to continuously detect a currenttemperature T of the exhaust stream and send signals includinginformation about said prevailing temperature T via the link 241 to the firstthe control unit 200.
    The first control unit 200 is arranged for communication withthe dosing unit 250 via a link 251. The first control unit 200 isarranged to control operation of the dosing unit 250 to e.g. regulate supplyof the reductant to the exhaust system of the vehicle 100.
    The dosing unit 250 may include a nozzle for dosing the reductantfor mixing with exhaust gases in an exhaust system of the vehicle 100. According to aembodiment, a geometry of said nozzle may be variable, wherein acontrol of the pressure Pr of the reductant can be achieved. The firstthe control unit 200 is arranged to influence said variable configuration ofthe dosing unit so as to control the pressure Pr of the reductant.
    According to one embodiment, the first control unit 200 is arranged to on the basis ofthe signals received from the pressure sensor 220 including information about aprevailing pressure of the reductant drive said pump 230 in a manner such as 1in accordance with one aspect of the innovative process. This is achieveda feedback control of the working pressure Pr.
    The first control unit 200 is arranged to calculate an exhaust mass flow MFin the exhaust gases from the vehicle's engine. The first control unit 200 is arrangedto continuously determine an exhaust mass flow MF of the exhaust gases fromthe engine of the vehicle. This can be done in any suitable way.101520253016According to one embodiment, the subsystem comprises a mass fl fate sensor (not shown)which is arranged to continuously measure a prevailing exhaust gas mass flow fromthe engine of the vehicle 100. Said mass flow sensor is arranged tocontinuously send signals including information about a prevailingexhaust mass flow to the first control unit via a link.
    The first control unit 200 is arranged to control the dosing unit 250dosing by means of a pressure Pr below which the reducing medium is dosed. Thethe first control unit 200 may be arranged to control the pressure Pr by controlof RPM speed of pump 230. The first control unit 200 may bearranged to control the pressure Pr by changing a throttle in the line 273for reducing medium from the dosing unit 250 to the container 205. According to aalternatively, the first control unit 200 is arranged to control the pressure Pr throughto change a throttle of reducing agent fl fate in the dosing unit 250,which reducing agent flow is intended to lead to the container 205. The firstthe control unit 200 may be arranged to control the pressure Pr by changingThe firstthe control unit 200 may be arranged to control the dosing unit 250configuration of the dosing unit 250 dosing device.dosing by means of the pressure Pr on the basis of a prevailing temperature T of aexhaust gas flow from an engine and / or a prevailing mass flow MF of exhaust gasesfrom an engine. The first control unit 200 may be arranged to controldosing of the dosing unit 250 by means of the pressure Pr of the reductant and acycle frequency CF at the dosage. The first control unit 200 may bearranged to vary the pressure Pr of the reductant within a range of [5, 15]bar. The first control unit 200 may be arranged to vary the pressure Pr atthe reductant steplessly in said control of the dosing unit 250dosage. The first control unit 200 may be arranged to vary the pressurePr of the reductant in discrete steps in said control of the dosing unit250 dosage. The first control unit 200 may be arranged to change onecycle frequency CF of the dosage steplessly or in discrete steps at saidcontrol of the dosage unit 250 dosage. The first control unit 200 canbe arranged to control the dosage of the dosing unit 250 by means of the pressure Pr101520253017of the reductant and a cycle frequency CF of the dosage on the basis of aprevailing exhaust gas temperature T and / or a prevailing exhaust gas mass flow MF ofexhaust gases from an engine of the motor vehicle.
    A second control unit 210 is provided for communication with the firstthe control unit 200 via a link 201. The second control unit 210 may bedetachably connected to the first control unit 200. The second control unit210 may be an external control unit for the vehicle 100. The second control unit210 may be arranged to perform the innovative process steps according tothe invention. The second control unit 210 can be used to overloadsoftware for the first control unit 200, in particular software for performingthe innovative procedure. The second control unit 210 may alternatively bearranged for communication with the first control unit 200 via an internalnetwork in the vehicle. The second control unit 210 may be arranged to performsubstantially the same functions as the first control unit 200, such as e.g.to control the dosing of the dosing unit 250 by means of a pressure Pr below whichreducing agents are dosed. The innovative procedure can be performed by itfirst control unit 200 or the second control unit 210, or boththe first control unit 200 and the second control unit 210.
    Below are some examples of how the working pressure Pr can be controlled by the firstthe control unit 200 for a few different operating cases of the motor vehicle 100.
    Example 1. In this case, a change from a reference state to one is determinedconditions with higher exhaust temperature T and higher exhaust mass flow MF (e.g.
    T> 400 degrees C and MF> 1000 kg / h.) The working pressure Pr is thereby lowered (from e.g.9 bar to 5 bar) to produce larger dosed reducing agent dropletswhich can be better controlled in the high exhaust flow and hit the desired hot surface inthe exhaust system of the vehicle. In this case, one is advantageously obtainedcontrolled wall hit.101520253018Example 2. In this case, a change from a reference state to one is determinedconditions with higher exhaust gas temperature T and lower mass flow (eg T> 40Odegrees C and MF <1000 kg / h). The working pressure Pr is thereby increased (from eg 9 bar to15 bar) to produce smaller reducing agent droplets which canevaporates directly into the exhaust stream before it hits a surface of the exhaust system ofthe vehicle. This advantageously provides improved evaporation ofreducing agent before wall hit.
    Example 3. In this case, a change from a reference state to one is determinedconditions with lower exhaust temperature T and higher exhaust mass flow MF, (e.g.
    T <250 degrees C and MF> 1000kg / h). The working pressure Pr can be maintained in this caseat a reference level (eg 9 bar) to provide onedroplet size distribution that contains both large and small droplets ofthe reducing agent. This means that some drops can be drawn into the exhaust gaswhile other droplets can be controlled by the flow. In this case, a largemeeting surface in the exhaust system of the vehicle to make the best use of itavailable heat energy and avoid local cooling.
    Example 4. In this case, a change from a reference state to one is determinedconditions with lower exhaust gas temperature T and lower exhaust gas mass flow MF, (e.g.
    T <250 degrees C and MF <1000kg / h). The working pressure Pr can be increased toproduce droplets that can evaporate more quickly on the surfaces inthe exhaust system that is hit or may have time to evaporate in the exhaust flow.
    This results in a rapid evaporation in the exhaust gas and / or on surfaces inthe exhaust system as this operating case has the lowest heat energy available forevaporation of said reducing agent.
    In a case of transient operation, the procedure can be supplemented so that controlbased on a previous operating case. According to one example, the exhaust system canof the vehicle after a long period of operation with relatively high exhaust gas temperature T anda relatively high exhaust flow will still be hot despite a prevailingexhaust mass flow and a prevailing exhaust temperature are currently low.101520253019In this case, a corresponding previously prevailing working pressure can advantageously continuebe used for an appropriate period of time.
    According to one aspect of the invention, the working pressure Pr can be controlled on the basis of achange of a detected exhaust back pressure in the vehicle. At an increase oneexhaust back pressure of the vehicle, the working pressure can advantageously be increased appropriatelymethod of maintaining a desired spray image for metered reducing agent.
    According to one aspect of the invention, the working pressure Pr can be controlled on the basis of aprevailing ambient air temperature of the vehicle.
    In a condition where the ambient air temperature is lower than 0 degrees Cthe working pressure can be increased in an appropriate manner, e.g. with 2 bar, to changethe droplet size distribution towards smaller droplets which can facilitate oneevaporation of dosed reducing agent.
    According to one aspect of the invention, the working pressure Pr can be controlled on the basis of aprevailing temperature of the reducing agent of the SCR system of the vehicle.
    In a condition where the prevailing temperature of the reducing agent is higherthan e.g. 50 degrees C, the working pressure can be lowered in a suitable way, e.g. with 2bar, to compensate for a faster evaporation rate than the hot onethe reducing agent entails.
    Figure 3a schematically illustrates a flow chart of a method of SCRsystem of a motor vehicle, comprising a feed device fora container feeding reducing agent to a dosage unit for delivery ofsaid reducing agent to an exhaust duct of the vehicle, according to aembodiment of the invention. The method comprises a first process steps301. Step s301 includes the step of controlling the dosage of the dosing unit101520253020by means of a pressure below which reducing agent is metered. After the step s301the procedure is terminated.
    Figure 3b schematically illustrates a flow chart of a method of SCRsystem of a motor vehicle, comprising a feed device fora container feeding reducing agent to a dosage unit for delivery ofreducing agent toembodiment of the invention.said an exhaust duct of the vehicle, according to aThe method includes a first method step s310. Procedure step s310involves the step of determining a prevailing temperature T of exhaust gases fromthe vehicle's 100 engine. This can be done by means of the temperature sensor 240. Afterthe process step s310 performs a subsequent process step s320.establish a prevailingexhaust gas mass flow MF of said exhaust gases. The exhaust mass flow MF can according toThe process step s320 includes the step ofan example is calculated with the first controller 200. Alternatively,the exhaust gas flow MF is detected by means of a suitable sensor or equipment. Afterthe process step s320 performs a subsequent process step s330.
    Method step s330 includes the step of controlling the dosage unit 250dosing by means of a pressure Pr under which reducing agent is dosed. The pressurePr can be changed by affecting a speed of the pump 230. The pressure Pr canalternatively or in combination is changed by affecting a throttle inline 273. The pressure Pr can alternatively or in combination be changed byto change the configuration of the dosing unit 250 dosing device.
    According to a preferred embodiment, the dosage of the dosing unit 250 is controlled by means ofthe pressure Pr on the basis of said determined prevailing temperature T atthe exhaust gas flow and / or on the basis of said established prevailingexhaust mass flow MF.101520253021After the process step s330, a subsequent process step s340 is performed.
    Method step s340 includes the step of controlling the dosage unit 250dosing by a cycle frequency of the SCR system. According to one embodimentsaid control of the dosing unit 250 dosing is performed by the pressurePr during which reducing agent is dosed at the same time as said control ofdosing unit 250 dosage by a cycle frequency of the SCRthe system is executed.
    According to one embodiment, the dosage of the dosing unit 250 is controlled by the pressure Prat the reductant and by means of a cycle frequency CF of the dosing simultaneouslyon the basis of said determined prevailing exhaust gas temperature T and / orsaid determined prevailing exhaust gas mass flow MF.
    After the procedure step s340, the procedure is terminated.
    Referring to Figure 4, a diagram of an embodiment of one is showndevice 400. The control units 200 and 210 described with reference toFigure 2 may in one embodiment comprise the device 400. The device 400includes a non-volatile memory 420, a data processing unit 410, and aread / write memory 450. The non-volatile memory 420 has a first memory portion 430wherein a computer program, such as an operating system, is stored for controlthe function of the device 400. Furthermore, the device 400 comprises a buscontroller, a serial communication port, an I / O device, an A / D converter, atime and date input and transfer unit, an event counter andan interrupt controller (not shown). The non-volatile memory 420 also hasa second memory part 440.
    A computer program P is provided which includes control routinesdosing of the dosing unit 250 by means of a pressure Pr below whichreducing agents are dosed. Program P includes routines for controlling the pressurePer by controlling the RPM speed of the pump 230. The program P101520253022includes routines for controlling the pressure Pr by changing a throttle inthe reduction medium line 273 from the metering unit 250 to the container205. According to an alternative, the program P includes routines for controlling the pressurePr by changing a restriction flow restrictor flow in the dosing unit250, which reducing agent flow is intended to lead to the container 205.
    The program P includes routines for controlling the pressure Pr by changingconfiguration of the dosing unit 250 dosing device. The program Pincludes routines for controlling the dosage of the dosage unit 250 by means ofthe pressure Pr on the basis of a prevailing temperature T of an exhaust gas flow from aengine and / or a prevailing mass flow MF of exhaust gases from an engine.
    Program P includes routines for controlling the dosage unit 250 dosageby the pressure Pr of the reductant and a cycle frequency CF of the dosage.
    The program P includes routines for varying the pressure Pr of the reductantwithin a range of [5, 15] Bar. Program P includes routines for varyingstepless atdosage unit 250 dosage. Program P includes routines forthe pressure Pr of the reductant said control ofvarying the pressure Pr of the reductant in discrete steps in said control ofdosage unit 250 dosage. Program P includes routines forchange a cycle frequency CF of the dosage steplessly or in discrete steps atsaid control of the dosing unit 250 dosage. The program Pincludes routines for controlling the dosage of the dosage unit 250 by means ofthe pressure Pr of the reductant and a cycle frequency CF of the dosing on a basisof a prevailing exhaust gas temperature T and / or a prevailing exhaust gas mass flow MFof exhaust gases from an engine of the motor vehicle.
    The program P can be stored in an executable way or in a compressed wayin a memory 460 and / or in a read / write memory 450.
    When it is described that the data processing unit 410 performs a certain functionit should be understood that the data processing unit 410 performs a certain part ofthe program which is stored in the memory 460, or a certain part of the program whichis stored in the read / write memory 450.101520253023The data processing device 410 can communicate with a data port 499 viaa data bus 415. The non-volatile memory 420 is for communicationwith the data processing unit 410 via a data bus 412. The separate memory460 is intended to communicate with the data processing unit 410 via adata bus 411.the data processing unit 410 via a data bus 414. To the data port 499 canfor example links 201, 221, 231, 241 and 251 are connected (see Figure 2).
    The read / write memory 450 is arranged to communicate withWhen data is received on data port 499, it is temporarily stored in the othermemory day 440. When received input is temporarily stored, isthe data processing unit 410 prepared to perform code execution ona manner described above. According to one embodiment, signals include receivedon the data port 499 information about a prevailing working pressure Pr at the reductantin the SCR system. According to one embodiment, signals received on includedata port 499 information on a prevailing temperature T of the exhaust gases in aexhaust system of the vehicle. According to one embodiment, signals include receivedon the data port 499 information about a prevailing exhaust mass flow MF atthe exhaust gases in an exhaust system of the vehicle.
    The received signals on the data port 499 can be used by the device400 to perform the innovative procedure herein.
    Parts of the methods described herein can be performed by the device 400 by means ofof the data processing unit 410 running the program stored in the memory 460or read / write memory 450. When the device 400 runs the program, it is executedprocedures described herein.
    The foregoing description of the preferred embodiments ofthe present invention has been provided for the purpose of illustrating and describingthe invention. It is not intended to be exhaustive or restrictivethe invention to the described variants. Obviously many will come24modifications and variations to be apparent to those skilled in the art. The embodimentswas selected and described to best explain the principles of the invention andits practical applications, thus enabling professionals to understandthe invention for different embodiments and with the different modifications asare suitable for the intended use.
    权利要求:
    Claims (26)
    [1]
    A method of SCR system of a motor vehicle (100: 110), comprising (230) for feeding from a container (205) reducing agent to a metering unit (250) for supplying said feeding device to reducing agent to an exhaust duct of the vehicle (100). ; 110), characterized by the step of: - controlling the dosing of the dosing unit (250) by means of a pressure (Pr) under which reducing agent is dosed.
    [2]
    The method of claim 1, further comprising the step of: - controlling the pressure (Pr) by controlling a speed (RPM) of said feeding device (230).
    [3]
    The method of claim 1 or 2, further comprising the step of: - controlling the pressure (Pr) by changing a throttle in a reducing agent return line (273) from the metering unit (250) to said container (205).
    [4]
    A method according to any one of the preceding claims, further comprising the step of: - controlling the pressure (Pr) by changing the configuration of the dosing unit (250).
    [5]
    A method according to any one of the preceding claims, further comprising the step of: - controlling the dosing of the dosing unit (250) by means of the pressure (Pr) on the basis of a prevailing temperature (T) of an exhaust gas fate from an engine and / or a prevailing mass flow (MF) in exhaust gases from an engine.
    [6]
    A method according to any one of the preceding claims, further comprising the step of: - controlling the dosing of the dosing unit (250) by means of the pressure (Pr) and a cycle frequency (CF) of the dosing.
    [7]
    A method according to any one of the preceding claims, further comprising the step of: - varying the pressure (Pr) of the reductant within a range of [5, 15] Bar. 10 15 20 25 30 26
    [8]
    A method according to any one of the preceding claims, further comprising the step of: - varying the pressure (Pr) of the reductant steplessly in said control of the dosage of the dosing unit (250).
    [9]
    A method according to any one of claims 1-7, further comprising the step of: - varying the pressure (Pr) of the reductant in discrete steps in said control of the dosage of the dosing unit (250).
    [10]
    A method according to any one of claims 6-9, further comprising the step of: - changing a cycle frequency (CF) of the dosage steplessly or in discrete steps in said control of the dosage of the dosing unit (250).
    [11]
    A method according to any one of the preceding claims, further comprising the step of: - controlling the dosing of the dosing unit (250) by means of the pressure (Pr) and a cycle frequency (CF) of the dosing on the basis of a prevailing exhaust gas temperature (T) and / or a prevailing exhaust mass flow ( MF) of exhaust gases from an engine of the motor vehicle (100; 110).
    [12]
    An SCR system of a motor vehicle (100; 110), comprising a (230) for reserving (205) reducing agent to a metering unit (250) for supplying said feeding device from a feeding reducing agent to an exhaust duct of the vehicle (100; 110). ), characterized by: - means (200; 210; 400) for controlling the dosing of the dosing unit (250) by means of a pressure (Pr) under which reducing agent is dosed.
    [13]
    The SCR system of claim 12, further comprising: - means (200; 210; 400) for controlling the pressure (Pr) by controlling a speed (RPM) of said feeding device (230). 10 15 20 25 30 27
    [14]
    The SCR system of claim 12 or 13, further comprising: - means (200; 210; 400) for controlling the pressure (Pr) by changing a throttle in a reducing agent return line (273) from the dosing unit (250) to said container (205).
    [15]
    An SCR system according to any one of claims 12 to 14, further comprising: - means (200; 210; 400) for controlling the pressure (Pr) by changing the configuration of the dosing unit (250).
    [16]
    An SCR system according to any one of claims 12 to 15, further comprising: - means (200; 210; 400) for controlling the dosing of the dosing unit (250) by means of the pressure (Pr) on the basis of a prevailing temperature (T) of an exhaust gas flow from an engine and / or a prevailing mass flow (MF) of exhaust gases from an engine.
    [17]
    An SCR system according to any one of claims 12-16, further comprising: - means (200; 210; 400) for controlling the dosing of the dosing unit (250) by means of the pressure (Pr) and a cycle frequency (CF) of the dosing.
    [18]
    An SCR system according to any one of claims 12 to 17, further comprising: - means (200; 210; 400) for varying the pressure (Pr) of the reductant within a range of [5, 15] Bar.
    [19]
    An SCR system according to any one of claims 12 to 18, further comprising: - means (200; 210; 400) for varying the pressure (Pr) of the reductant steplessly in said control of the dosage of the dosing unit (250).
    [20]
    The SCR system according to any one of claims 12 to 18, further comprising: - means (200; 210; 400) for varying the pressure (Pr) of the reductant in discrete steps in said control of the dosage of the dosing unit (250).
    [21]
    An SCR system according to any one of claims 17 to 20, further comprising: means (200; 210; 400) for changing a cycle frequency (CF) of the dosage steplessly or in discrete steps in said control of dosage unit (250) dose fi ng.
    [22]
    An SCR system according to any one of claims 12-21, further comprising: - means (200; 210; 400) for controlling the dosing of the dosing unit (250) by the pressure (Pr) and a cycle frequency (CF) of the dosing on the basis of a prevailing exhaust gas temperature (T) and / or a prevailing exhaust mass flow (MF) of exhaust gases from an engine of the motor vehicle (100; 110).
    [23]
    A motor vehicle (100; 110) comprising an SCR system according to any one of claims 12-22.
    [24]
    A motor vehicle (100; 110) according to claim 23, wherein the motor vehicle is something of a truck, bus or passenger car.
    [25]
    A computer program (P) comprising one (230) for (205) reducing means to a metering unit (250) for supplying said SCR system, feeding device from a container feeding reducing agent to an exhaust duct of the vehicle (100; 110), wherein said computer program (P) comprises program code stored on a medium for causing an electronic control unit (200; 400) or another computer (210; 400) connected to the electronic control unit (200; 400) to perform the steps according to any one of claims 1 -11.
    [26]
    A computer program product comprising a program code stored on a computer readable medium for performing the method steps of any of claims 1-11, when said computer program is run on an electronic control unit (200; 400) or another computer (210; 400) connected to the electronic control unit (200; 400).
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    同族专利:
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    EP2791485A4|2015-08-26|
    SE536241C2|2013-07-16|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JP2008196375A|2007-02-13|2008-08-28|Toyota Motor Corp|Exhaust emission control device of internal combustion engine|
    GB2460825A|2008-06-06|2009-12-16|Delphi Tech Inc|Reagent dosing system|
    DE102009023325B4|2008-12-10|2012-01-26|Continental Automotive Gmbh|Method for adapting the injection of injection agent in an injection system|
    DE102009035940C5|2009-08-03|2017-04-20|Cummins Ltd.|SCR exhaust treatment device|
    US8915062B2|2009-10-09|2014-12-23|GM Global Technology Operations LLC|Method and apparatus for monitoring a reductant injection system in an exhaust aftertreatment system|
    SE535326C2|2010-04-23|2012-06-26|Scania Cv Ab|Method and system for determining the need for replacement or cleaning of a filter unit in a liquid dosing system of an SCR system|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE1151192A|SE536241C2|2011-12-14|2011-12-14|Method of reducing agent dosing in an SCR system with pressure control based on a temperature at exhaust pipes|SE1151192A| SE536241C2|2011-12-14|2011-12-14|Method of reducing agent dosing in an SCR system with pressure control based on a temperature at exhaust pipes|
    BR112014014298A| BR112014014298A2|2011-12-14|2012-12-12|method belonging to a scr system and a scr system|
    US14/365,230| US20140331647A1|2011-12-14|2012-12-12|Method pertaining to an scr system and an scr system|
    PCT/SE2012/051378| WO2013089625A1|2011-12-14|2012-12-12|Method pertaining to an scr system and an scr system|
    CN201280069719.XA| CN104114825A|2011-12-14|2012-12-12|Method pertaining to an SCR system and an SCR system|
    SE1251409A| SE537527C2|2011-12-14|2012-12-12|Procedure for an SCR system and an SCR system|
    EP12857883.8A| EP2791485A4|2011-12-14|2012-12-12|Method pertaining to an scr system and an scr system|
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