SE1351463A1 - Method of initiating dosing of reducing agent in an SCR system and an SCR system - Google Patents

Abstract

SUMMARY The invention relates to a method in an SCR system comprising a pump (230) and a dosing unit (250), comprising the steps of: - determining (s410) the need to heat a reducing agent arranged in a container (205) for exhaust gas purification; - if a determined need is to heat, continuously hot said reducing agent, by means of a heating medium circulating through said container (205); - continuously determining (s420) a temperature (Tred) has said reducing agent in said container (205); - determining a level (L) has said reducing agent in said container (205); - continuously determining (s430) an accumulated amount (V) of narrow reducing agent; determine (s440) that the start of circulation of said reducing agent is suitable when said fixed temperature (Tred) has 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 one predetermined first setpoint (VTh1); and / or - determining (s440) that the start of dosing of said reducing agent is appropriate when said fixed temperature (Tred) has 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 said level (L) has said reducing agent in said container (205) included (s440) in determining start-up luminosity with respect to said circulation and / or said dosage. 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 an SCR system and a motor vehicle (100) equipped with the SCR system.

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 for implementing 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 holding 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, said reductant in the container and other parts of the SCR system will freeze at an ambient temperature below a certain time below said freezing point.

According to applicable emission regulations, certain vehicles equipped with an SCR system must normally be operated after a certain predetermined time after 2 start-ups of the vehicle. According to an example, said predetermined time may be 70 minutes. In this case, the 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 one aspect, if a pump start-up and dosing agent dosing is appropriate, a temperature sensor is presently provided in the container to supply a radiating temperature with 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 has, for example, a 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 large 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 have 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 201 211 3669 describes a method for melting a urea solution having 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. 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 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 having a motor vehicle in which a reducing agent for exhaust gas purification 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 start-up of an SCR system having 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 8. 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, including the steps of: - determining the need to heat a reducing agent arranged in a container for exhaust gas purification; 4 - if a determined need is made for hot, continuously hot said reducing agent, by means of a heating medium circulating through said container; - continuously determining a temperature of said reducing agent in said container; - fixing a level has said reducing agent in said container; - continuously determining an accumulated amount of narrow reducing agent; determine that the start of circulation of said reducing agent is appropriate when said fixed temperature has 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 - determining that the start of dosing of said reducing agent is appropriate as said fixed temperature having 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; said level having 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 an aspect of the invention, it can be avoided when dosing or consumption of reducing agent can be started.

According to one aspect of the invention, there is provided a method of an SCR system comprising a pump and a dosing unit, including the steps of: - determining the need to heat a reducing agent arranged in a container for exhaust gas purification; if there is a 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; - fixing a level has said reducing agent in said container; - continuously determining an accumulated amount of narrow reducing agent; determine that start-up of circulation of said reducing agent is appropriate when said fixed temperature has 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, including the steps of: - determining the need to heat a reducing agent arranged in a container for exhaust gas purification; if there is a 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; - fixing a level has said reducing agent in said container; - continuously determining an accumulated amount of narrow reducing agent; - determining that the start of dosing of said reducing agent is appropriate cla said temperature determined has said reducing agent in said container exceeding a predetermined second temperature value and / or the determined accumulated amount of narrow reducing agent exceeds a predetermined second amount value; - including said level has said reducing agent in said container in determining start-up luminosity with respect to said dosage; and - where appropriate, activate 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 having 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, whereby 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 6 circulation of reducing agent and / or dosing of reducing agent is accumulated. The 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 straightening 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: - adding extra 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 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 said first temperature value, second temperature value, first setpoint and second setpoint 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 procedure may further comprise the step of: - compensating for a reduced level 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. In this case, both circulation start and dosing start can be delayed as appropriate with prior art to achieve a reliable method in an SCR system in which at least a part of said reducing agent has said container 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 amount of thawed reducing agent at the start of circulation of reducing agent and / or start of 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, if 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 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 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 initial temperature value and / or the determined accumulated amount of narrow reducing agent exceeds a predetermined initial amount; and / or means adapted to determine that start-up 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; and - means adapted to include said level of said reducing agent in said container in determining start-up luminosity 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 feasibility 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: 9 - 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 8-14.

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 controller or another computer connected to the electronic controller to perform the steps of any of claims 1-7.

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 another computer connected to the electronic control unit to perform the steps of any of claims 1-7, when said program code is crossed on said electronic control unit or said other computer.

According to one aspect of the present invention, computer programs are provided in an SCR system, said computer program comprising program code stored on a computer readable medium for causing an electronic control unit or another computer connected to the electronic control unit to perform the steps of any of the claims 1-7.

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 1-7, when said program code 'cars on an electronic control unit or other computer connected to it. electronic 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 process steps of any of claims 1-7, when said program code is crossed on an electronic controller or other 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 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 the teachings herein 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 throughout the 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.

The term "lank" refers to a communication link which may be a physical line, such as an optoelectronic communication line, or a non-physical line, such as a wireless connection, for example a radio or microwave line.

Hari refers to the term "reductant" as a means used to react with certain emissions in an SCR system. These emissions can e.g. be NOR gas. Said reductant is 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. A heating element can be an electric heating element which is energized by e.g. one or more batteries (not shown). Alternatively, a heating element may be a coolant-based heating element which uses coolant water from an engine of the vehicle to heat said reductant in a reducing agent container of the SCR system.

It was pointed out 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 that 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 are selected by a system comprising a NON generator, for example a diesel engine, the exhaust gases of which are to be purified.

In this he uses the term "conduit" to a passage to line and transport a fluid, such as e.g. a reductant in liquid form. The pipe can be a rudder of any dimension. The cable can consist of an arbitrary, suitable 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 line 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 to 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 an appropriate amount of reductant to an exhaust system having 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) attached to 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 applicable, narrow frozen reductant is present therein by energy transfer. According to this example, the first fluid line 281 is arranged to lead coolant water heated by the engine of the vehicle in a closed loop through the container 205 and a second fluid line 282 back to the engine has the vehicle 100. According to an exemplary embodiment, a pump (not shown) is arranged to feeding said fluid through said first fluid line 281 and said second fluid line 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 may be a conventional coolant pump.

According to another embodiment, said fluid may be fed through said first fluid conduit 281 and said second fluid conduit 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. Said pump 230 can be of any suitable 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 present therein. A third heating element 263 is arranged at the third line 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 radiator 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. Various 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 may be arranged around the lines 271 and 273 in the container 205.

A first control unit 200 is arranged to control 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 drive said heating element when circulation of said reducing agent in 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. The first temperature sensor 221 is arranged to detect a radiating temperature Tred has the reductant where the sensor is mounted. According to one embodiment, the first temperature sensor 221 is arranged in the immediate vicinity of the first line 271 and / or the third line 273 in the container 205. According to one embodiment, the first temperature sensor 221 is arranged in the immediate vicinity of 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 16 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 the 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. regulating 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 when 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 when it 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 load Over program code to the first control unit 200, in particular program code to carry 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 applicable, at least a part of said narrow reductant is extracted from the container 205 to enable heating thereof by at least 17 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 the SCR. the 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 supply a radiating temperature T2 having said fluid upstream of said container 205. Said second temperature sensor 222 is arranged to continuously send signals including information of radiating temperature T2 having the fluid to the first control unit 200 via said line L222. Said second temperature sensor 222 may be provided in the immediate vicinity of 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 having said fluid downstream of said container 205. Said third temperature sensor 223 is arranged to continuously send signals including information of radiating temperature T3 having the fluid to the first control unit 200 via said line L223. Said third temperature sensor 223 may be dangerously arranged in the immediate vicinity of the tank 205 at a downstream side thereof or at the engine of the vehicle or in a suitable place between said motor and said tank 205. According to an example, said third temperature sensor 223 may be arranged 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 18 connected to said first temperature sensor 221, second temperature sensor 222 and said third temperature sensor 223 .

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, the 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 was pointed out 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 existing in the vehicle. In this case, either a vehicle external feeding device or a dart & intended feeding device of the vehicle can be used for circulation of said heating fluid.

According to an 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 a temperature difference therefrom 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 upstream of said container 205.

The first control unit 200 is according to an embodiment arranged that on the basis of the received signals comprising a radiating temperature 13 the fluid downstream of said container 205 and a radiating temperature T2 of the fluid upstream of said 19 container 205 is determined 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 lb! ' 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 has 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 with the first control unit 200 via a long L245. Said level sensor 245 is arranged to continuously or intermittently determine a radiating level L has said reducing agent in said container 205. Said level sensor is arranged to continuously or intermittently send signals comprising information of said determined radiating level L having said reducing agent to the first named controller. lank L245. Said level sensor 245 may 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 temperature Tred has 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 has 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 of circulation of said reducing agent is suitable when said fixed temperature Tred has said reducing agent in said container 205 exceeds a predetermined first temperature value Th1 and / or the determined accumulated amount V narrows a reduction value. VTh1.

The first control unit 200 is arranged to determine that the start of dosing of said reducing agent is suitable when said fixed temperature Tred has said narrow reducing agent in said container 205 exceeds a predetermined second temperature value Th2 and / or the determined accumulated amount V narrows a second reducing agent above mangdvarde VTh2.

The first control unit 200 is arranged to include the said reducing agent in said level L in said container when determining the start-up lamp 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 value VTh1 and second setpoint value 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 involve raising said second predetermined temperature value Th2. According to one example, said second predetermined temperature value Th2 may be increased by 1 or 5 degrees Celsius, as from -1 degrees Celsius to 0 or 4 degrees Celsius. In a similar manner, the first 21 manifold VTh1 and the said second manifold VTh2 can be raised to appropriate and the manifold, respectively.

The first control unit 200 may be arranged to supply extra heating time after the start-up luminosity achieved has been compensated 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. The initiation is controlled by initiating circulation of reducing agent and / or initiating dosing of reducing agent 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 in said narrow reducing agent in said container 205.

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, said narrow reducing agent in said container.

Named respective time periods are appropriate time 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 circulation of reducing agent is zero (0) minutes. According to one embodiment, said delay regarding said initiation of reducing agent dosing is 10 minutes and said delay regarding said initiating reduction of circulating agent 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 22 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 circulation of reducing agents 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 of the said first temperature value Th1, second temperature value Th2, first set mat Vth1 and second set mat Vth2 are larger the more reduced the level L is relative to a possible highest level.

The first control unit 200 is arranged to activate start-up of said circulation and said dosing, respectively, when start-up is determined to be suitable. Activation of the start-up of said circulation and said dosing, respectively, can be considered appropriate when at least one of said first temperature value Th1, second temperature value Th2, first set mat Vth1 and second set mat Vth2 have 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 arranged in a container 205 for exhaust gas purification; - if a fixed need is identified, hot, continuously hot 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 has said reducing agent in said container 205; - continuously determining an accumulated amount of V narrow reducing agent; 23 - 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 value1; and / or - 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 narrow reducing agent exceeds a predetermined second amount value; wherein said 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. 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 judged that there is a need to heat a reducing agent arranged in a container 250 for exhaust gas purification by means of a container named 205 circulating heating medium. This can be done at start-up of the vehicle 100. Need to heat 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 process comprises a first process 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 said first temperature sensor 221. Alternatively, said temperature Tred may be estimated / calculated / modeled by the first control unit 200 according to routines stored therein. 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 routines stored therein. After the procedure step s420, a subsequent procedure 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 means of the first control unit 200 on the basis of information on, for example, the first temperature 12 having said reducing agent upstream of said container and the second temperature 13 having said reducing agent. downstream 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 has said reducing agent upstream said container 205 and the second temperature T3 has said reducing agent downstream said container 205. The accumulated amount of narrow reducing agent V in the container 205 can according to one embodiment 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 s440 is performed.

The process step s440 may include the step of determining that the start-up of circulation of said reducing agent is appropriate when said fixed temperature Tred has said reducing agent in said container 205 exceeds a predetermined first temperature value Th 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 has 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 comprise that said level L has said reducing agent in said container 205 is involved in determining start-up luminosity with respect to said circulation and / or said dosage.

After the step step s440, a subsequent step 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 with the so-called first control unit 200. It should be noted that actual dosing after starting dosing only takes place when it is appropriate, depending on various factors, such as radiating load and / or exhaust temperature of the vehicle's 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, there is shown a diagram of an embodiment of a device 500. The controllers 200 and 210 described with 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 of a computer program, such as an operating system, stored to control the operation of the device 500. Further, the device 500 includes a bus controller, a serial communication port , I / O means, an A / D 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 comprises routines for, in an SCR system comprising a pump 230 and a dosing unit 250: - determining the need to heat a reducing agent for exhaust gas cleaning arranged in a container 205; - if a fixed need is identified, hot, continuously hot 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 start-up 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 narrows a reduction value. VThl. The computer program P may comprise routines for determining that the 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 comprise routines for determining said first temperature value Th1, second temperature value Th2, first setpoint VTh1 and second setpoint VTh2 on the basis of said determined level L. 27 The computer program P may comprise routines for supplying extra heating time after the start-up lamp has been reached. 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 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 highest level in such a way 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 dosing at start-up. 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 outputs 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 28 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 method, 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 cat program stored in the memory 560 or the read / write memory 550. When the device 500 cat program is executed in the methods described.

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 chosen and described in order to clarify the principles of the invention and its practical applications, and thus make it possible for a person skilled in the art to understand the invention for different embodiments and with the various modifications which are suitable for the intended use. 29

Claims (18)

Patent claims A method of an SCR system comprising a pump (230) and a dosing unit (250), comprising the steps of: - determining (s410) the need to heat a reducing agent arranged in a container (205) for exhaust gas purification; - if a determined need is to heat, continuously hot said reducing agent, by means of a heating medium circulating through said container (205); - continuously determining (s420) a temperature (Tred) has said reducing agent in said container (205); - determining a level (L) has said reducing agent in said container (205), characterized by the steps of: - continuously determining (s430) an accumulated amount (V) of narrow reducing agent; determine (s440) that the start of circulation of said reducing agent is suitable when said fixed temperature (Tred) has 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 one predetermined first setpoint (VTh1); and / or - determining (s440) that the start of dosing of said reducing agent is appropriate when said fixed temperature (Tred) has 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 setpoint (VTh2); wherein said level (L) has said reducing agent in said container (205) included (s440) in determining start-up luminosity with respect to said circulation and / or said dosage. A method according to claim 1, comprising the step of: - determining said first temperature value (Th1), second temperature value (Th2), first setpoint (VTh1) and second setpoint (VTh2) on the basis of said determined level (L). A method according to claim 1 or 2, further comprising the step of: - supplying 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). A method according to any one of claims 1-3, further comprising the step of: - raising said first temperature value (Ti), second temperature value (12), first setpoint (V1) and second setpoint (V2) 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 1-4, further comprising the step of: - including said level (L) having 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 1-5, further comprising the step of: - 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: - 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: - means (200; 210; 500) adapted to determine the need to heat a reducing agent for exhaust gas cleaning arranged in a container (205); means (200; 210; 500; 230; 281) adapted to, if a determined need to heat, continuously heat 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: 31 - 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 suitable 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) narrow reducing agent Exceeds a predetermined first amount (VTh1); and / or means (200; 210; 500) adapted to determine that the start of dosing of said reducing agent is appropriate when 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 level (L) of said reducing agent in said container (205) in determining start-up luminosity of said circulation and / or said dosage. An SCR system according to claim 8, comprising: - means (200; 210; 500) adapted to determine said first temperature value (Th1), second temperature value (Th2), first setpoint (VTh1) and second setpoint (VTh2) on the basis of named fixed level (L). SCR system according to claim 8 or 9, 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 8-10, comprising: - means (200; 210; 500) adapted to raise 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). An SCR system according to any one of claims 8 to 11, comprising: 32 - 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 8 to 12, comprising: - means (200; 210; 500) adapted to compensate for a reduced level (L) relative to a monthly maximum level in such a way that the more reduced the level (L) is the longer heating time before the respective start-up An SCR system according to any one of claims 8-13, comprising: - 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 8-14. A motor vehicle (100; 110) according to claim 15, wherein the motor vehicle is something 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 another computer (210; 500) connected to the electronic control unit (200; 500) performing the steps according to any one of claims 1-7. A computer program product comprising a program code stored on a computer readable medium for performing the method steps of any of claims 1-7, when said program code is executed on an electronic control unit (200; 500) or another computer (210; 500) connected to the electronic control unit (200; 500). 1/4 100 K 112