SE537851C2 - Method of initiating dosing of reducing agent in an SCR system and an SCR system - Google Patents

Abstract

SUMMARY A procedure for starting the dosing of a reducing agent in an SCR system where the reducing agent has been frozen. The method comprises: - determining (s410) the need for a hot reducing agent arranged in a container (205) for exhaust gas purification; if there is a fixed need for hot, continuously hot reducing agent; - continuously determine (s420) a temperature (Tred); a level (L) of the reducing agent in the container (205) and an accumulated amount (V) of narrow reducing agent; determine (s440) after the start of circulation of the reducing agent is appropriate d6 said temperature (Tred) of the reducing agent in the container (205) Exceeds a predetermined first temperature value (Th1) and / or the accumulated amount (V) of narrow reducing agent exceeds a predetermined first amount value (VTh1); and / or - determining (s440) that the start of dosing of the reducing agent is appropriate if the temperature (Tred) of the reducing agent in the container exceeds a predetermined second temperature value (Th2) and / or the accumulated amount (V) of narrow reducing agent exceeds a predetermined second amount value ( VTh2); wherein the level (L) of the reducing agent in the container (205) is included (s440) in determining start-up luminosity with respect to circulation and / or dosage.

Description

TECHNICAL FIELD The present invention relates to a method of an SCR system. The invention also relates to a computer program product comprising program code for a computer to implement a method according to the invention. The invention also relates to an SCR system and a motor vehicle equipped with the SCR system.

BACKGROUND In today's vehicles, e.g. urea as a reductant in SCR systems comprising an SCR catalyst, in which catalyst said reductant and NOR gas can react with each other and be converted to nitrogen gas and water. Different types of reductants can be used in SCR systems. These reductants have different freezing points. A common reductant is e.g. AdBlue.

One type of SCR system includes a container that hails a reductant. The SCR system also has a pump which is arranged to pump up said reductant from the container via a suction hose and supply it via a pressurized hose to a dosing unit which is arranged at an exhaust system of the vehicle. The dosing unit is arranged to inject a required amount of reductant into the exhaust system upstream of the SCR catalyst according to drivers stored in a control unit of the vehicle.

Said reductant may have a freezing point within a range of -10 to -15 degrees Celsius. Different reductants have unique freezing points depending on, among other things, their amnesic composition. For example, AdBlue has a freezing point at about -11 degrees Celsius. In this case, the said reductant in the container and other parts of the SCR system will freeze if an ambient temperature for a certain time falls below the said freezing point. 1 According to gallant regulations regarding issues, certain vehicles equipped with an SCR system are normally operated after a certain predetermined time after the start-up of the vehicle. According to an example, said predetermined time can be 70 minutes. Thus, frozen reducing agent must be at least partially melted in order to be able to circulate in the SCR system before dosing is started within the said time period.

According to an edge set to request the start-up of the pump and the dosing agent dosing is suitable, a temperature sensor is presently provided arranged in the container to supply a radiating temperature of said reducing agent. In this case, it can be determined with a certain degree of probability whether the said reducing agent in the container has been thawed or not. A disadvantage of the said method is that temperature feeds as a base do not always give a correct assessment, depending on, for example, where the sensor is mounted, the configuration of, for example, the suction hose and the configuration and size of the container. The temperature sensor itself also has a certain food insecurity. In this case, the rather large security SCR system is far too early. If the pump is started up too early, as an insufficient amount of reducing agent has thawed, there is a risk that the pump "sucks dry", which can have a number of undesirable effects. An example of such an undesirable effect is that air enters the SCR system, which can significantly impair the performance of the system. Furthermore, effective continued thawing of frozen reducing agent is prevented. In cases where a circulating reducing agent is used for cooling a dosing unit for reducing agent, this can be overheated when circulation is disturbed or absent.

In some cases, where frozen reducing agent in the tank, for example, is thawed by means of a circulating heating medium, and where the pump sucks dry, a situation may arise where frozen reducing agent in the container can not be further thawed by means of said circulating heating medium. This can have extremely serious consequences, as biased legal requirements bile emissions of the vehicle can not be met within the required time. Furthermore, the pump may be at risk of permanent damage or suffer from high wear if it is started up prematurely.

WO 2012113669 describes a method for melting a urea solution of an SCR system in which the temperature of said urea solution and the amount of urea solution in a container for said urea solution are taken into account. 2 SUMMARY OF THE INVENTION There is thus a need to reliably assess whether a pump in the SCR system where reducing agents have been frozen can be started up, without using excessive safety measures to avoid the said undesirable effects as the pump is forced to suck dry.

An object of the present invention is to provide a new and advantageous method in an SCR system.

Another object of the invention is to provide a new and advantageous SCR system and a new and advantageous computer program in an SCR system.

A further object of the invention is to provide an alternative method in an SCR system, an alternative SCR system and an alternative computer program in an SCR system of a motor vehicle in which an exhaust gas reducing agent is at least partially frozen.

A further object of the invention is to provide a method of an SCR system, an SCR system and a computer program for achieving a reliable commissioning of an SCR system of a motor vehicle.

A further object of the invention is to provide a method of an SCR system, an SCR system and a computer program for improving the performance of a motor vehicle.

Some of said objects are achieved by a method in an SCR system according to claim 1. Other objects are achieved by an SCR system according to claim 7. Advantageous embodiments are stated in the dependent claims.

According to one aspect of the invention, there is provided a method of an SCR system comprising a pump and a dosing unit, comprising the steps of: 3 determining the need to heat a reducing agent arranged in a container for exhaust gas purification; in the determined need to heat, continuously heating said reducing agent, by means of a heating medium circulating through said container; continuously determining a temperature of said reducing agent in said container; determining a level of said reducing agent in said container; continuously determining an accumulated amount of narrow reducing agent; determining that the start-up of circulation of said reducing agent is appropriate, the said fixed temperature of said reducing agent in said container exceeds a predetermined first tin temperature value and / or the determined accumulated amount of narrow reducing agent exceeds a predetermined first amount value; and / or determining that the start of dosing of said reducing agent is appropriate when said fixed temperature of said reducing agent in said container exceeds a predetermined second temperature value and / or the determined accumulated amount of narrow reducing agent exceeds a predetermined second nang value; wherein said level of said reducing agent in said container is included in determining start-up luminosity with respect to said circulation and / or said dosage.

Advantageously, according to one aspect of the invention, it may be decided when dosage or consumption of reducing agent may be 'Abodes.

According to one aspect of the invention, there is provided a method of an SCR system comprising a pump and a dosing unit, comprising the steps of: determining the need to heat a reducing agent arranged in a container for exhaust gas purification; if determined need to heat, continuously heating said reducing agent, by means of a heating medium circulating through said container; continuously determining a temperature of said reducing agent in said container; determining a level of said reducing agent in said container; continuously determining an accumulated amount of narrow reducing agent; 4 determining that the start-up of circulation of said reducing agent is appropriate when said determined temperature of said reducing agent in said container exceeds a predetermined first temperature value and / or the determined accumulated amount of narrow reducing agent exceeds a predetermined first amount value; including said level of said reducing agent in said container in determining start-up luminosity with respect to said circulation; where appropriate, start said circulation of said reducing agent.

According to one aspect of the invention, there is provided a method of an SCR system comprising a pump and a dosing unit, comprising the steps of: determining the need to heat a reducing agent arranged in a container for exhaust gas purification; if determined need to heat, continuously heating said reducing agent, by means of a heating medium circulating through said container; continuously determining a temperature of said reducing agent in said container; determining a level of said reducing agent in said container; continuously determining an accumulated amount of narrow reducing agent; determine that the start of dosing of said reducing agent is appropriate when said fixed temperature of said reducing agent in said container exceeds a predetermined second temperature value and / or the determined accumulated amount of narrow reducing agent exceeds a predetermined second amount value; including said level of said reducing agent in said container in determining start-up luminosity with respect to said dosage; and where appropriate, activating said dosage of said reducing agent.

At a reduced level of reducing agent in said container relative to a maximum possible level, reducing agent in certain heating configurations will to a lesser extent be exposed to existing heating configuration for heating said reducing agent in said container. In this case, a radiating level of said reducing agent in said container can be taken into account when calculating a radiating narrow amount of reducing agent in said container. This can advantageously be effected by means of a factor, wherein a reduced level of reducing agent in said container means that an amount of narrow reducing agent required to allow the start-up of said circulation of reducing agent and / or dosing of reducing agent is accumulated. Said raising factor can for example be 25% when the container is half full. Said raising factor can for instance be 50% when the container is filled to a quarter. Said uplift can be provided in fixed discrete steps or stepless.

By considering the said level of reducing agent in said container, the circulation of reducing agent and / or the starting of dosing of reducing agent can take place under essentially optimal conditions, within the set time and with a sufficient amount of thawed reducing agent to ensure things and reliable operation of said SCR. -system.

The method may comprise the step of: determining said first temperature value, second temperature value, first setpoint and second setpoint on the basis of said determined level. In this way, things are achieved, robust and reliable operation of the said SCR system.

The method may further comprise the step of: supplying additional heating time after achieved start-up longevity to compensate for a reduced level relative to a possible highest level of reducing agent in said container. In this way, things are achieved, robust and reliable operation of the said SCR system.

The method may further comprise the step of: raising said first temperature value, second temperature value, first quantity value and second quantity value to compensate for a reduced level relative to a possible highest level of reducing agent in said container. This provides a simple and automated method for achieving reliable operation of the said SCR system. In this case, a cost-effective method is provided which achieves at least some of the above-mentioned objects.

The method may further comprise the step of: raising the said first tin temperature value, second tin temperature value, first nanang value value and second quantity value on the basis of said determined level of said reducing agent. This is done to compensate for a reduced level relative to a possible highest level of reducing agent in said container.

The method may further comprise the step of: including said level of said reducing agent in said container in determining start-up luminosity with respect to said dosage alone.

The method may further comprise the step of: compensating for a reduced level relative to a possible maximum level in such a way that the more reduced the level, the longer the heating time before the respective start-up. reliable method in an SCR system where at least a part of said reducing agent of said container is in solid (frozen) form.

The method may further comprise the step of: activating the start-up of said circulation and said dosing, respectively, when start-up is determined to be appropriate.

Advantageously, containers for reducing agents that are partially filled will not contain too small a thawed reducing agent when starting the circulation of reducing agent and / or starting dosing of reducing agent.

According to one aspect of the present invention, there is provided an SCR system comprising a pump and a dosing unit, comprising: means adapted to determine the need to heat a reducing agent for exhaust gas cleaning arranged in a container; means adapted to, at a determined need to heat, continuously heat said reducing agent, by means of a heating medium circulating through said container; Means adapted to continuously determine a tin temperature of said reducing agent in said container; means adapted to determine a level of said reducing agent in said container; means adapted to continuously determine an accumulated amount of narrow reducing agent; means adapted to determine that start-up of circulation of said reducing agent is appropriate as said determined temperature of said reducing agent in said container exceeds a predetermined first temperature value and / or the determined accumulated amount of narrow reducing agent exceeds a predetermined first amount value; and / or means adapted to determine that initiation of dosing of said reducing agent is appropriate when said determined tin temperature of said reducing agent in said container exceeds a predetermined second temperature value and / or the determined accumulated amount of narrow reducing agent exceeds a predetermined second amount value; and means adapted to include said level of said reducing agent in said container in determining start-up fluidity of said circulation and / or said dosage.

The SCR system may comprise: means adapted to determine said first temperature value, second temperature value, first setpoint and second setpoint on the basis of said determined level.

The SCR system may comprise: means adapted to supply extra heating time after achieved start-up luminosity in order to compensate for a reduced level relative to a possible highest level of reducing agent in said container.

The SCR system may comprise: means adapted to increase said first temperature value, second temperature value, first quantity value and second quantity value to compensate for a reduced level relative to a possible highest level of reducing agent in said container. The SCR system may comprise: means adapted to include said level of said reducing agent in said container when determining start-up luminosity with respect to said dosage alone.

The SCR system may include: means adapted to compensate for a reduced level relative to a possible maximum level in such a way that the more reduced the level, the longer the heating time before the respective start-up.

The SCR system may comprise: means adapted to activate the start-up of said circulation and the said dosage, respectively, when start-up is determined to be appropriate.

According to one aspect of the present invention, there is provided a motor vehicle comprising an SCR system according to any of claims 7-12.

Said motor vehicle can be anything from a truck, bus or car.

According to one aspect of the present invention, computer programs are provided in an SCR system, said computer program comprising program code for causing an electronic control unit or a computer connected to the electronic control unit to perform the steps of any of claims 1-6.

According to one aspect of the present invention, computer programs are provided in an SCR system, wherein said computer program includes program code for causing an electronic controller or another computer connected to the electronic controller to perform the steps of any of claims 1-6, said program code. an aspect of the present invention is provided with computer programs in an SCR system, said computer programs comprising program code stored on a computer readable by a computer 9 for causing an electronic control unit or another computer connected to the electronic control unit to perform the steps according to any of the claims 1-6.

According to one aspect of the present invention, there is provided a computer program product comprising a program code stored on a computer readable medium for performing the method steps of any of claims 1-6, when said program code is crossed on an electronic control unit or another computer connected to the electronic the control unit.

According to one aspect of the present invention, there is provided a computer program product comprising a program code non-volatile stored on a computer readable medium for performing the method steps of any of claims 1-6, when said program code 'cars on an electronic control unit or another computer connected to the electronic control unit.

Additional objects, advantages and novel features of the present invention will become apparent to those skilled in the art from the following details, as well as through the practice of the invention. While the invention is described below, it should be understood that the invention is not limited to the specific details described. Those skilled in the art having access to laroma hari will recognize additional applications, modifications, and incorporations within other fields which are within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention and further objects and advantages thereof, reference is now made to the following detailed description which is to be read in conjunction with the accompanying drawings in which like reference numerals refer to like parts in the various figures, and in which: 1 schematically illustrates a vehicle, according to an embodiment of the invention; Figure 2 schematically illustrates a subsystem of the vehicle shown in Figure 1, according to an embodiment of the invention; Figure 3 schematically illustrates a subsystem of the vehicle shown in Figure 1, according to an embodiment of the invention; Figure 4a schematically illustrates a flow chart of a method, according to an embodiment of the invention; Figure 4b schematically illustrates in further detail a flow chart of a method, according to an embodiment of the invention; and Figure 5 schematically illustrates a computer, according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE FIGURES Referring to Figure 1, a side view of a vehicle 100 is shown. The exemplary vehicle 100 consists of a tractor 110 and a trailer 112. The vehicle may be a heavy vehicle, such as a truck or a bus. The vehicle can alternatively be a car.

Herein the term "lank" refers to a communication link which may be a physical line, such as an opto-electronic communication line, or a non-physical line, such as a wireless connection, for example a radio or microcarriage line.

The term "reductant" refers to an agent used to react with certain emissions in an SCR system. These emissions can e.g. be NON gas. Said reductant according to an embodiment so-called AdBlue. Of course, other types of reductants can be used. Here, AdBlue is mentioned as an example of a reductant, but a person skilled in the art realizes that the inventive process and the inventive SCR system can be realized for other types of reductants, with the necessary adaptations, such as e.g. adaptations to adequate freezing point for selected reductants, in control algorithms for executing program code in accordance with the inventive method.

The term "heating element" refers to a device which is arranged to heat an adjacent component, such as e.g. a line, pump or dosing unit containing said reductant. The heating elements specified therein are thus arranged to heat the reductant at different positions in the vehicle 100. An 11 warning element may be an electric warning element which is arranged below e.g. one or more batteries (not shown).

Alternatively, a heating element may be a coolant-based heating element which uses radiator water Iran an engine of the vehicle to heat said reductant in a reducing agent container of the SCR system.

It should be noted that the invention is suitable for application to any SCR system and is thus not limited to SCR systems of motor vehicles. The inventive method and the inventive SCR system according to an aspect of the invention are suitable for other platforms which include an SCR system on motor vehicles, such as e.g. watercraft. The watercraft can be of any kind, such as e.g. motor boats, ships, ferries or ships.

The inventive method and the inventive SCR system according to an aspect of the invention are also suitable for e.g. systems including tractors, dumpers, power tools, industrial engines and / or powered industrial robots.

The inventive method and the inventive SCR system according to an aspect of the invention also illuminate choices for different types of power plants, such as e.g. an electric power plant comprising a diesel generator.

The inventive method and the inventive SCR system make choices for an arbitrary motor system which includes a motor and an SCR system, such as e.g. at a locomotive or other platform.

The inventive method and the inventive SCR system make choices for a system that includes a NOR generator, for example a diesel engine, whose exhaust gases are to be purified.

In this case the term "line" refers to a passage for holding and transporting a fluid, such as e.g. a reductant in liquid form. The conduit can be a tube of any 12 dimension. The line can consist of an arbitrary, land-based material, such as e.g. plastic, rubber or metal.

Referring to Figure 2, a subsystem 299 of the vehicle 100 is shown. The subsystem 299 may be located in the tractor 110. The subsystem 299 may form part of an SCR system. According to this example, the subsystem 299 consists of a container 205 which is arranged to hold a reductant. The container 205 is arranged to contain a suitable amount of reductant and is further arranged to be able to be filled if necessary.

A first line 271 is arranged to direct the reductant to a pump 230 from the container 205. Said pump is 230 arranged to pump up the reductant from the container 205 via the first line 271 and via a second line 272 supply said reductant to a dosing unit 250. The pump 230 is arranged to pressurize the reductant in the second line 272.

The dosing unit 250 is arranged to supply said reductant to an exhaust system (not shown) of the vehicle 100. More specifically, the dosing unit 250 is arranged to supply in a controlled manner a land-based reduced reductant to an exhaust system of the vehicle 100. According to this embodiment, an SCR catalyst is (not shown) arranged downstream a low supply of the reductant is provided. The amount of reductant supplied to the exhaust system is intended to be used in the SCR catalyst to reduce the amount of unwanted emissions.

A third conduit 273 is presently disposed between the metering device 250 and the container 205. The third conduit 273 is arranged to return a certain amount of the reductant fed to the metering unit 250 to the container 205.

A first fluid conduit 281 is arranged to hold and transport a fluid. Said fluid is a heating medium. Said fluid may be coolant for an engine (not shown) of the vehicle 100. The first fluid conduit 281 is partially disposed in the container 205 to heat the reductant present therein. The first fluid conduit 281 is partially disposed in the container 205 so that, where appropriate, frozen freezing reductant is present therein by energy transfer. The first fluid conduit 281 provided in this example is arranged to direct coolant heated by the engine of the vehicle 13 in a closed loop through the container 205 and a second fluid conduit 282 back to the engine of the vehicle 100.

According to one example, a pump (not shown) is provided to feed said fluid through said first fluid conduit 281 and said second fluid conduit 282 to effect heating of said reductant in said container 205. In case said fluid comprises coolant for said engine of the vehicle, said pump consists of a conventional coolant pump.

According to another embodiment, said fluid may be fed through said first fluid line 281 and said second fluid line 282 to effect heating of said reductant in said container 205 by means of said pump 230. In this case said pump 230 is arranged to feed both said reducing agent as said fluid. It should be noted that said reducing agent and said fluid are not mixed, but are fed in separate loops.

Said pump 230 can also be referred to as a feeding means or circulation pump. The said pump 230 may be of any country-type type. Said pump 230 may be a diaphragm pump. Said pump 230 can according to one embodiment be heated with a circulating heating medium. According to an example, for example, the first line 271 may be arranged to heat the pump 230 downstream of said container 205. According to an alternative, the pump may be heated with a circulating medium provided by equipment intended for this purpose.

According to one embodiment, the first fluid conduit 281 is partially configured as a coil, which coil is arranged around said first conduit 271 and said third conduit 273 present in the container 205, as schematically shown in Figure 2. With this configuration an efficient heating or melting is achieved of the reductant in the container 205. The first fluid line 281 may alternatively have another lamp shape, for example a U-shape.

A first heating element 261 is arranged at the second line 272 to heat the reductant present therein if necessary. A second heating element 262 is provided at the metering valve 250 to heat, if necessary, both the metering valve 250 and the reductant clan. A third warning element 263 is provided at the third conduit 273 to heat the reductant present therein if necessary. Said first heating element 261, second heating element 262 and third heating element 263 may be electric heating elements.

According to an exemplary embodiment, the lines 271, 272 and 273 can be arranged to be heated by means of coolant water for cooling the engine of the vehicle. Harvid can s.k. Two-channel pipes are provided, used in two separate passages for reducing agents and coolant water are arranged close to each other for efficient heat transfer.

It should be noted that according to the invention it is possible to place a heating element in an arbitrarily suitable place in the subsystem 299, for example in the container 205. Different configurations of said heating element are possible to realize. According to one example, heating elements may be placed in said container 205 to heat any reducing agent present therein. Said heating element may be an electric heating element. Said heating elements may comprise an appropriate number of separate heating elements. Said electric heating element may be a helical electric loop, which loop according to an example column may be arranged around the lines 271 and 273 in the container 205.

A first control unit 200 is arranged to control the operation of said first heating element 261, said second heating element 262 and said third heating element 263 in an appropriate manner. Said first control unit 200 may be arranged to control operation of said first heating element 261, said second heating element 262 and said third heating element 263 independently of each other. According to one embodiment, the first control unit is arranged to activate and operate said heating element when circulation of said reducing agent of the SCR system is judged to be suitable.

The first control unit 200 is arranged for communication with a first temperature sensor 221 via a line L221. Said first temperature sensor 221 is arranged to detect a radiating temperature Tred of the reductant when the sensor is mounted. According to an embodiment of the first temperature sensor 221 arranged in close proximity to the first line 271 and / or the third line 273 in the container 205. According to an embodiment of the first temperature sensor 221 arranged in integral proximity to the first line 271 and / or the third line 273 at the bottom of the container 205. According to one embodiment, the first temperature sensor 221 is arranged in a lower part of the container 205. The temperature sensor 221 is arranged to continuously send signals to the first control unit 200 including information about said radiating temperature Tred of the reductant via line L221.

The first control unit 200 is arranged for communication with the pump 230 via a line 230. The first control unit 200 is arranged to control operation of the pump 230 in order to e.g. controlling the flow of the reductant within the subsystem 299. The first control unit 200 is arranged to activate circulation of said reducing agent when it is judged to be suitable, according to an embodiment of the present invention.

The first control unit 200 is arranged for communication with the dosing unit 250 via a long L250. The first control unit 200 is arranged to control the operation of the dosing unit 250 in order to e.g. regulating the supply of the reductant to the exhaust system of the vehicle 100. The first control unit 200 is arranged to activate circulation of said reducing agent by means of said pump 230 as it is judged to be suitable, according to an embodiment of the present invention. The first control unit 200 is arranged to activate dosing of said reducing agent which is judged to be suitable, according to an embodiment of the present invention.

A second control unit 210 is arranged for communication with the first control unit 200 via a long L210. The second control unit 210 may be releasably connected to the first control unit 200. The second control unit 210 may be a control unit external to the vehicle 100. The second control unit 210 may be arranged to perform the inventive process steps. The second control unit 210 can be used to upload program code to the first control unit 200, in particular program code, for carrying out the inventive method. The second control unit 210 may alternatively be arranged for communication with the first control unit 200 via an internal network in the vehicle. The second control unit 210 may be arranged to perform substantially similar functions to the first control unit 200.

According to the embodiment schematically illustrated with reference to Figure 2, the first control unit 200 is arranged to control the pump 230 in such a way that, where appropriate, at least a part of said narrow reductant is extracted from the container 205 to enable heating thereof by at least some of the heating elements 261, 262 and 263 outside the container 205. The first control unit 200 is further arranged to control the pump 230 in such a way that the narrow part of said reductant is returned to the container 205 before dosing thereof by means of the dosing unit 250 is drilled in SCR system.

Figure 3 schematically illustrates a part of the subsystem 299 which is described with reference to Figure 2. Figure 3 omits some of the components described with reference to Figure 2.

The first control unit 200 is arranged for communication with a second temperature sensor 222 via a long L222. Said second temperature sensor 222 is arranged to continuously feed a radiating temperature T2 of said fluid upstream of said container 205. Said second temperature sensor 222 is arranged to continuously send signals including radiating temperature T2 information of the fluid to the first control unit 200 via said line L222. Said second temperature sensor 222 may be provided in integral proximity to the container 205 at an upstream side thereof or at the engine of the vehicle or in a suitable place between said engine and said container 205.

The first control unit 200 is arranged for communication with a third temperature sensor 223 via a long L223. Said third temperature sensor 223 is arranged to continuously supply a radiating temperature T3 of said fluid downstream of said container 205. Said third temperature sensor 223 is arranged to continuously send signals including radiating temperature information 13 of the fluid to the first control unit 200 via said line L223. Said third temperature sensor 223 may be provided in the immediate vicinity of the container 205 at a downstream side thereof or at the engine of the vehicle or in a suitable place between said engine and said container 205. According to an example, said third temperature sensor 223 may be provided at the pump 230.

According to one embodiment, said first control unit 200 is arranged to communicate with said first temperature sensor 221, second temperature sensor 222 and said third temperature sensor 223 via said second control unit 210. which may be signal connected to said first temperature sensor 221, second temperature sensor 222 and said third temperature sensor .

Said first conduit 281 is arranged to conduct a heating fluid to effect melting of frozen reducing agent in the container 205. According to one example, said first conduit is provided for cooling an engine of the vehicle. During said cooling of the engine, thermal energy is transferred from said engine to said fluid. According to one example, said fluid is a coolant of an engine cooling system. According to one example, said pump 230 is arranged to circulate said fluid from the motor to the container 205 and Ater to the motor via the line 282 in a closed loop. It should be noted that said reducing agent and said heating fluid are never mixed but are physically separated by said conduits.

According to an alternative embodiment, a vehicle external heating medium can be used. According to this embodiment, a separate container with a heating medium can be used, whereby the container can be connected to a circulation line present in the vehicle. In this case, either a vehicle external feeding device or a feeding device intended for this purpose of the vehicle can be used for circulation of said heating fluid.

According to one embodiment, the first control unit 200 is arranged to control the operation of the pump 230 and the dosing unit 250 on the basis of the received signals comprising a radiating temperature Tred of the reductant at the area of the temperature sensor 221 and a radiating temperature 12 of the fluid upstream of said container 205.

According to an embodiment, the first control unit 200 is arranged to determine on the basis of the received signals comprising a radiating temperature Tred of the reductant at the area of the temperature sensor 221 and a radiating temperature 12 of the fluid upstream of said container 205 a temperature difference thereof.

The first control unit 200 is according to an embodiment arranged on the basis of the received signals comprising a radiating temperature 13 of the fluid downstream of said container 205 and a radiating temperature T2 of the fluid upstream of said container 205 to determine a temperature difference thereof according to an aspect of the innovative procedure.

The first control unit 200 may be arranged to continuously determine an accumulated amount of V narrow reducing agent in the container on the basis of said determined temperature difference T3-T2 of said reducing agent and elapsed time for heat transfer.

The first control unit 200 may be arranged to continuously determine an accumulated amount of V narrow reducing agent in the container on the basis of said determined temperature difference T2-Tred of said reducing agent and elapsed time for heat transfer.

Said accumulated amount of narrow reducing agent V in the container 205 can then be modeled / calculated / estimated in an appropriate manner.

A level sensor 245 is arranged in said container 205. Said level sensor 245 is arranged for communication below the first control unit 200 via a long L245. Said level sensor 245 is arranged to continuously or intermittently determine a radiating level L of said reducing agent in said container 205. Said level sensor is arranged to continuously or intermittently send signals including information about said determined radiating level L of said reducing agent to the first control unit 200. lank L245. Said level sensor 245 can be a float sensor. Said level sensor 245 may include a suitable electronic, optoelectronic or electromechanical sensor. Said level sensor 245 may include, for example, a laser sensor or UV sensor.

The first control unit 200 is arranged to determine the need to heat a reducing agent for exhaust gas cleaning arranged in said container 205 by means of a heating medium circulating through said container. The first control unit 200 is arranged to initiate operation of the SCR system according to the present invention when it has been determined that there is a need to heat (narrow) said reducing agent in said container. The first control unit 200 is arranged to continuously determine a tin temperature Tred of said reducing agent in said container 205. This can be done by means of said first temperature sensor 221. The first control unit 200 is arranged to determine a level L of said reducing agent in said container 205. This can take place by means of said level sensor 245. The first control unit 200 is arranged to continuously determine / calculate / model / estimate an accumulated amount of V narrow reducing agent in said container 205.

The first control unit 200 is arranged to determine that the start-up of circulation of said reducing agent is appropriate as said fixed temperature Tred of said reducing agent in said container 205 exceeds a predetermined first temperature value Th1 and / or the determined accumulated amount V narrowly reduced VTh1.

The first control unit 200 is arranged to determine that the start of dosing of said reducing agent is appropriate as said fixed temperature Tred of said narrow reducing agent in said container 205 exceeds a predetermined second temperature value Th mangdvarde VTh2.

The first control unit 200 is arranged to include said level L of said reducing agent in said container in determining start-up luminosity with respect to said circulation and said dosing, respectively.

The first control unit 200 may be arranged to determine said first temperature value Th1, second temperature value Th2, first setpoint VTh1 and second setpoint VTh2 on the basis of said determined level L. This may include raising said first predetermined temperature value Th1. According to one example, said first predetermined temperature value may be increased by 3 or 7 degrees Celsius, as from -5 degrees Celsius to -2 or 2 degrees Celsius. This may include raising said second predetermined temperature value Th2. According to one example, said second predetermined temperature value Th2 may be raised by 1 or 5 degrees Celsius, as from -1 degrees Celsius to 0 or 4 degrees Celsius. In a similar way, the first first value VTh1 and the second second value VTh2 can be increased to land and the respective values.

The first control unit 200 may be arranged to supply extra heating time after achieved start-up luminosity in order to compensate for a reduced level L relative to a possible highest level of reducing agent in said container. In this case, the first predetermined temperature value Th1 and the said second predetermined temperature value Th2 are not adjusted. Instead, initiation of circulation of reducing agent and / or initiation of dosing of reducing agent is controlled so that respective initiation is delayed by an appropriate period of time after said first predetermined temperature value Th1 and said second predetermined temperature value Th2 are reached at said narrow reducing agent in said container.

In this case, the first predetermined setpoint VTh1 and the said second predetermined setpoint VTh2 are not adjusted. Instead, initiation of circulation of reducing agent and / or initiation of dosing of reducing agent is controlled so that respective initiation is delayed by an appropriate period of time after said first predetermined setpoint VTh1 and said second predetermined setpoint VTh2 have been reached in said narrow reducing agent in name.

The respective time periods are lamable periods. The respective time periods can be 2, 5 or 10 minutes. Said time periods may be different on board. According to one embodiment, a delay with respect to said initiation of dosing agent reduction is substantially longer than said delay with respect to said initiation of circulation of reducing agent. According to one embodiment, said delay regarding said initiation of reducing agent dosing is 5 minutes and said delay regarding said initiating reduction of reducing agent circulation is zero (0) minutes. According to one embodiment, said delay regarding said initiation of dosing agent reduction is 10 minutes and said delay regarding said initiation of reducing agent circulation is 2 minutes.

The first control unit 200 may be arranged to raise said first temperature value Th1, second temperature value Th2, first quantity value VTh1 and 21 second quantity values Vth2 to compensate for a reduced level L relative to a possible highest level of reducing agent in said container 205.

The first control unit 200 may be arranged to include said level L of said reducing agent in said container 205 in determining start-up luminosity with respect to said dosage alone. In this case, there is no delay in initiating the circulation of reducing agent on the basis of the said level L.

The first control unit 200 is arranged to compensate for a reduced level L relative to a possible highest level in such a way that the more reduced the level, the longer the heating time before the respective start-up. This may also mean that changes in the said first temperature value Th1, second temperature value Th2, first set mat Vth1 and second set mat Vth2 are large the more reduced the level L is relative to a possible highest level.

The first control unit 200 is arranged to activate the start-up of said circulation and said dosing, respectively, when start-up is determined to be appropriate. Activation of the start-up of the said circulation and the said dosage, respectively, can be considered necessary when at least one of said first temperature values Th1, second temperature value Th2, first set mat Vth1 and second set mat Vth2 has been reached. The at least one value and / or mat has been corrected on the basis of said reduced level L relative to a possible highest level.

Figure 4a schematically illustrates a flow chart of a process in an SCR system comprising a pump 230 and a dosing unit 250. The process comprises a first process step s401. Step s401 includes the steps of: determining the need to heat a reducing agent provided in a container 205 for exhaust gas purification; if determined need to heat, continuously heating said reducing agent, by means of a heating medium circulating through said container 205; continuously determining a temperature Tred of said reducing agent in said container 205; determining a level L of said reducing agent in said container 205; continuously determining an accumulated amount of V narrow reducing agent; Determine that the start of circulation of said reducing agent is appropriate when said fixed temperature Tred of said reducing agent in said container 205 exceeds a predetermined first temperature value Th1 and / or the determined accumulated amount V narrow reducing agent exceeds a predetermined first amount value; and / or determining that the start of dosing of said reducing agent is appropriate cla said fixed temperature Tred of said reducing agent in said container 205 exceeds a predetermined second temperature value Th2 and / or the determined accumulated amount V narrow reducing agent exceeds a predetermined second amount value VTh2; wherein said level L of said reducing agent in said container 205 includes s440 in determining start-up luminosity with respect to said circulation and / or said dosage. After procedure step s401, the procedure is terminated.

Figure 4b schematically illustrates a flow chart of a process in an SCR system comprising a pump 230 and a dosing unit 250. The process can be activated when it is determined that there is a need to heat a reducing agent arranged in a container 250 for exhaust gas cleaning under a named container. 205 circulating heating medium. This can be done at start-up of the vehicle 100. Need to warn said reducing agent can be determined if said reducing agent is at least partially in frozen form in said container 205. This can be determined on the basis of information about radiating temperature of ambient air, radiating temperature of reducing agent, exposure time taking into account ambient air temperature, type of reducing agent (freezing point, etc).

The method comprises a first method step s410. The process step s410 may include the step of continuously determining a temperature Tred of said reducing agent in said container 205. This may be done by means of said first temperature sensor 221. Alternatively, said temperature Tred may be estimated / calculated / modeled by means of the first control unit 200 according to therein stored routines. After the procedure step s410, a subsequent procedure step s420 is performed. The method step s420 may include the step of determining a level L of said reducing agent in said container 205. This may be done by said level sensor 245. Alternatively, said level L may be estimated / calculated / modeled by means of the first control unit 200 according to therein stored routines. After the step step s420, a subsequent step step s430 is performed.

The process step s430 may include the step of continuously determining an accumulated amount of narrow reducing agent V in the container 205. This may be done by the first control unit 200 on the basis of information such as the first temperature 12 of said reducing agent upstream of said container and the second temperature 13 of said container. reducing agent downstream of said container 205. This can be done by means of the first control unit 200 on the basis of information on a difference between the first temperature T2 of said reducing agent upstream of said container 205 and the second temperature T3 of said reducing agent downstream of said container 205. The accumulated amount narrowly According to one embodiment, reducing agent V in the container 205 can be modeled / calculated / estimated by means of the first control unit 200 according to routines stored therein. After the step step s430, a subsequent step step s440 is performed.

The process step s440 may include the step of determining that start-up of circulation of said reducing agent is appropriate as said fixed temperature Tread of said reducing agent in said container 205 exceeds a predetermined first temperature value Th1 and / or the determined accumulated amount V VThl.

The process step s440 may include the step of determining that the start of dosing of said reducing agent is appropriate when said fixed temperature Tred of said reducing agent in said container 205 exceeds a predetermined second temperature value Th2 and / or the determined accumulated amount V narrowly a second reducing agent ; The process step s440 may involve including said level L of said reducing agent in said container 205 in determining start-up luminosity with respect to said circulation and / or said dosage. After the procedure step s440, a subsequent procedure step s450 is performed.

The process step s450 may include the step of, where appropriate, starting circulation of reducing agent in said SCR system. In this case, said reducing agent can advantageously be heated. Heating can take place by means of at least one of the heating elements 261, 262 and 263. Heating can alternatively or additionally be heated by means of said fluid in the line 281.

The time for starting said circulation is then determined according to the inventive method on the basis of said determined level L of said reducing agent in said container 205. After the process step s450, a subsequent process step s460 is performed.

The process step s460 may include the step of, where appropriate, initiating said dosing of said reducing agent by means of said dosing unit 250. It is to be understood that actual dosing does not necessarily have to be performed. Actual dosing is carried out according to stored routines of the said first control unit 200. In this case, it should be noted that actual dosing after the start of dosing only takes place when it is mandatory, depending on various factors, such as radiating load and / or exhaust temperature of the vehicle engine.

The time for starting said dosing is then determined according to the inventive method on the basis of said determined level L having said reducing agent in said container 205.

After the step step s460, the procedure is terminated.

Referring to Figure 5, a diagram of an embodiment of a device 500 is shown. The controllers 200 and 210 described in reference to Figure 2 may in one embodiment include the device 500. The device 500 includes a non-volatile memory 520, a data processing unit 510, and a read / write memory 550. The non-volatile memory 520 has a first memory portion 530 used in a computer program, such as an operating system, stored to control the operation of the device 500. Furthermore, the device 500 comprises a bus controller, a serial communication port, I / O means, an AID converter, a time and date input and transfer unit, a trade calculator and an interrupt controller (not shown). The non-volatile memory 520 also has a second memory portion 540.

A computer program P is provided which includes routines for, in an SCR system comprising a pump 230 and a dosing unit 250: determining the need to heat a reducing agent arranged in a container 205 for exhaust gas purification; if determined need to heat, continuously heating said reducing agent, by means of a heating medium circulating through said container 205; continuously determining a temperature Tred of said reducing agent in said container 205; and determining a level L of said reducing agent in said container 205.

The computer program P may include routines for continuously determining an accumulated amount of narrow reducing agent. The computer program P may comprise routines for determining that the start-up of circulation of said reducing agent is appropriate as said fixed temperature Tred of said reducing agent in said container 205 exceeds a predetermined first temperature value Th1 and / or the determined accumulated amount V narrow reducing amount exceeds a predetermined amount. VThl. The computer program P may comprise routines for determining that start-up of dosing of said reducing agent is appropriate as said fixed temperature Tred of said reducing agent in said container 205 exceeds a predetermined second temperature value Th2 and / or the determined accumulated amount V narrow reducing agent exceeds a predetermined second value. . VTh2. The computer program P may include routines for including said level L of said reducing agent in said container 205 in determining start-up luminosity with respect to said circulation and / or said dosage.

The computer program P may include routines for determining the first temperature value Th1, the second temperature value Th2, the first setpoint VTh1 and the second setpoint VTh2 on the basis of said determined level L. 26 The computer program P may include routines for supplying additional heating time a reduced level L relative to a possible highest level of reducing agent in said container 205.

The computer program P may include routines for raising said first temperature value Th1, second temperature value Th2, first setpoint value VTh1 and second setpoint value VTh2 to compensate for a reduced level L relative to a possible highest level of reducing agent in said container 205.

The computer program P may include routines for including said level of said reducing agent in said container 205 in determining start-up luminosity with respect to said dosage alone.

The computer program P may comprise routines for compensating for a reduced level L relative to a possible maximum level so that the more reduced the level, the longer the heating time before each start-up. The computer program P may include routines for activating the start of said circulation and said dosage determined to be appropriate.

The program P can be stored in an executable manner or in a compressed manner in a memory 560 and / or in a read / write memory 550.

When it is described that the data processing unit 510 performs a certain function, it should be understood that the data processing unit 510 performs a certain part of the program which is stored in the memory 560, or a certain part of the program which is stored in the read / write memory 550.

The data processing device 510 can communicate with a data port 599 via a data bus 515. The non-volatile memory 520 is intended for communication with the data processing unit 510 via a data bus 512. The separate memory 560 is intended to communicate with the data processing unit 510 via a data bus 511. Read / write memory 550 is arranged to communicate with the data processing unit 5 27 via a data bus 514. To the data port 599, e.g. the lanes L210, L221, L222, L223, L230, L245 are connected (see Figure 2 and Figure 3).

When data is received on the data port 599, it is temporarily stored in the second memory part 540. Once the received input data has been temporarily stored, the data processing unit 510 is ready to perform code execution in a manner described above. According to one embodiment, signals received at the data port 599 include information about a radiating temperature Tred of the reducing agent in the container 205. According to one embodiment, signals received at the data port 599 include information about a radiating temperature T2 of said heating medium upstream of the container 205. According to one embodiment, signals received include on the data port 599 information about a radiating temperature T3 of said heating medium downstream of the container 205.

Parts of the methods described herein may be performed by the device 500 by means of the data processing unit 510 which the Icor program stored in the memory 560 or the lasiskry memory 550. When the device 500 Icor program, the methods described are executed.

The foregoing description of the preferred embodiments of the present invention has been provided for the purpose of illustrating and describing the invention. It is not intended to be exhaustive or to limit the invention to the variations described. Obviously, many modifications and variations will occur to those skilled in the art. The embodiments were selected and described in order to best explain the principles of the invention and its practical applications, thereby enabling those skilled in the art to understand the invention for different embodiments and with the various modifications which are appropriate to the intended use. 28

Claims (16)

A method of an SCR system comprising a pump (230) and a dosing unit (250), comprising the steps of: 1. determine (s410) the need for a hot reducing agent arranged in a container (205) for exhaust gas purification; 2. if determined need of hot, continuous hot said reducing agent, by means of a heating medium circulating through said container (205); - continuously determining (s420) a temperature (Tred) of said reducing agent in said container (205); - determining a niv8 (L) of said reducing agent in said container (205), characterized by the steps aft: - continuously determining (s430) an accumulated amount (V) of narrow reducing agent; determining (s440) from the start of circulation of said reducing agent is appropriate when said determined temperature (Tred) of said reducing agent in said container (205) exceeds a predetermined first temperature value (Th1) and / or the determined accumulated amount (V) of narrow reducing agent exceeds predetermined first plural (VTh1); and / or - determining (s440) from the start of dosing of said reducing agent is appropriate d8 said determined temperature (Tred) of said reducing agent in said container exceeds a predetermined second temperature value (Th2) and / or the determined accumulated amount (V) of narrow reducing agent exceeds a predetermined second set of values (VTh2); wherein the said fixed level. (L) of said reducing agent in said container (205) is included (s440) in determining start-up luminosity with respect to said circulation and / or said dosage and wherein said first temperature value (Th1), second temperature value (Th2), first manifold value (VTh1) and others the setpoint (VTh2) is determined on the basis of the said fixed level (L). The method of claim 1, further comprising the step of: - providing additional heating time after achieved start-up luminosity to compensate for a reduced level (L) relative to a possible highest level of reducing agent in said container (205). 29 A method according to any one of claims 1 or 2, further comprising the step of: 1. raising said first temperature value (Th1), second temperature value (Th2), first setpoint (VTh1) and second setpoint (VTh2) to compensate for a reduced level (L) relative to a possible highest level of reducing agent in said container (205). A method according to any one of claims 1-3, further comprising the step of: 1. including said level (L) of said reducing agent in said container (205) in determining start-up luminosity with respect to said dosage alone. A method according to any one of claims 1-4, further comprising the step of: 1. compensating for a reduced level (L) relative to a possible highest level in such a way that the more reduced the level, the longer the heating time before the respective start-up A method according to any one of claims 1-5, further comprising the step of: 1. activating the start-up of said circulation and said dosing, respectively, when start-up is determined to be appropriate. An SCR system comprising a pump (230) and a dosing unit (250), comprising: 1. means (200; 210; 500) adapted to determine any need to heat a reducing agent arranged in a container (205) for exhaust gas purification; means (200; 210; 500; 230; 281) adapted to, if determined, all hot, continuously hot said reducing agent, by means of a heating medium circulating through said container (205); means (200; 210; 500; 221) adapted to continuously determine a temperature (Tred) of said reducing agent in said container (205); Means (200; 210; 500; 245) adapted to determine a level (L) of said reducing agent in said container (205), characterized by: 3. means (200; 210; 500) adapted to continuously determine an accumulated amount (V) narrow reducing agent; means (200; 210; 500) adapted to determine that the start of circulation of said reducing agent is appropriate when said fixed temperature (Tred) of said reducing agent in said container (205) exceeds a predetermined first temperature value (Th1) and / or the determined the accumulated amount (V) of narrow reducing agent exceeds a predetermined first amount value (VTh1); and / or - means (200; 210; 500) adapted to determine the start of dosing of said reducing agent are suitable as said determined temperature (Tred) of said reducing agent in said container (205) exceeds a predetermined second temperature value (Th2) and / or the determined accumulated amount (V) of narrow reducing agent exceeds a predetermined second amount value (VTh2); and means (200; 210; 500) adapted to include said determined level (L) of said reducing agent in said container (205) in determining start-up luminosity of said circulation and / or said dosage, wherein said means (200; 210; 500 ) are adapted to determine said first temperature value (Th1), second temperature value (Th2), first setpoint (VTh1) and second setpoint (VTh2) on the basis of said set level (L). An SCR system according to claim 7, comprising: - means (200; 210; 500) adapted to supply extra heating time after achieved start-up luminosity to compensate for a reduced level (L) relative to a possible highest level of reducing agent in said container (205). ). An SCR system according to any one of claims 7 or 8, comprising: - means (200; 210; 500) adapted to raise said first temperature value (Th1), second temperature value (Th2,), first setpoint (VTh1) and second setpoint ( VTh2) for aft compensate for a reduced level (L) relative to a miijlig highest level of reducing agent in narrinda behalf are (205). An SCR system according to any of claims 7-9, comprising: - means (200; 210; 500) adapted to include said level (L) of said reducing agent in said container (205) in determining start-up luminosity with respect to said dosage alone. An SCR system according to any one of claims 7-10, comprising: 31 means (200; 210; 500) adapted to compensate for a reduced level (L) relative to a possible highest level so as to increase the more reduced level ( L) is the longer heating time before the respective start-up An SCR system according to any one of claims 7-11, comprising: 1. means (200; 210; 500) adapted to activate the start-up of said circulation and said dosing, respectively, when start-up is determined to be appropriate. Motor vehicle (100; 110) comprising an SCR system according to any one of claims 7-12. A motor vehicle (100; 110) according to claim 13, wherein the motor vehicle is any of a truck, bus or passenger car. Computer program (P) in an SCR system, wherein said computer program (P) comprises program code for causing an electronic control unit (200; 500) or a computer (210; 500) connected to said electronic control unit (200; 500) performing the steps according to any one of claims 1-6. A computer program product comprising a program code stored on a computer readable medium for performing the process steps according to any one of claims 1-6, when said program code 'cars on an electronic control unit (200; 500) or a computer (210; 500) connected to the said electronic control unit (200; 500). 32 1/4 100 K 112