EATS for converting NOx emissions in exhaust gas from an engine

Abstract

An EATS for converting NOx emissions in exhaust gas from an engine, the EATS comprising: a fluid passage (40) for providing a fluid path for the exhaust gas; a selective catalytic reduction, SCR, catalyst (32) arranged in the fluid passage, the SCR catalyst being configured to store ammonia; an injector (34) configured to inject a reducing agent to provide ammonia to the SCR catalyst, the injector being arranged upstream of the SCR catalyst; a fluid flow inducer (56, 58) configured to induce a fluid flow in at least a portion of the fluid passage when the engine is off; and a control device (17) configured to pre-condition the EATS by injecting a reducing agent into the fluid passage before the engine is started and to transport the reducing agent into the SCR catalyst by the induced fluid flow, thereby storing ammonia in the SCR catalyst.

Description

Technical Field

[0001] This invention relates to an exhaust aftertreatment system (EATS) for converting NOx emissions from engine exhaust, and a method for pre-adjusting at least a portion of the EATS. The invention also relates to a control device for a vehicle, a vehicle, and a computer program. Background Technology

[0002] Vehicles typically include an engine for propulsion. This engine can be an internal combustion engine powered by, for example, liquid or gaseous fuel, or it can be an electric motor powered by electricity. Furthermore, hybrid power solutions exist, in which the vehicle is propelled by both an internal combustion engine and an electric motor.

[0003] In the case of internal combustion engines (such as diesel engines), vehicles are typically equipped with an Exhaust Aftertreatment System (EATS) to treat emissions from the engine. EATS for diesel engines typically include one or more of the following components: diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR) catalyst. A reducing agent (such as urea or an ammonia-containing substance) is usually injected upstream of the SCR catalyst, thereby helping, with the aid of the catalyst, to convert nitrogen oxides (also known as NOx) into diatomic nitrogen (N2) and water, and possibly carbon dioxide (CO2) (depending on the choice of reducing agent). The cleaned or at least reduced exhaust then exits the EATS and the vehicle through the vehicle's exhaust pipe. Other types of engines that produce emissions at least partially similar to those of diesel engines may use the same or similar EATS.

[0004] Government regulations and the ongoing demand for improved vehicle fuel economy necessitate more efficient operation of EATS (Energy Emission Reduction Systems). For example, EATS must heat up rapidly and maintain high conversion efficiency under very low loads and during engine cold starts at low exhaust temperatures. The need for highly efficient engines to meet stringent CO2 requirements also leads to lower exhaust temperatures and higher NOx levels, necessitating the injection of large amounts of reductant upstream of the SCR catalyst. Furthermore, when urea is used as a reductant, it requires heat to evaporate and hydrolyze into ammonia. Low temperatures, such as during engine cold starts, significantly increase the risk of crystallization and deposit formation, reducing the effectiveness of EATS.

[0005] EATS can be pre-conditioned before engine start. In some examples, EATS pre-conditioning is performed by heating components or subsystems of the EATS to raise its temperature to closer to its operating temperature before it begins processing exhaust from the engine. This thermal pre-conditioning of the EATS requires energy. Furthermore, because the EATS constitutes a large thermal buffer within the vehicle, including thermally interconnected components, thermal pre-conditioning may be performed with relatively low precision, as the supplied heat dissipates and is transferred to other EATS components unintended. Moreover, if thermal preconditioning is performed too early (i.e., relatively early compared to engine start), heat loss can reduce the efficiency of pre-conditioning. Therefore, the industry needs improved pre-conditioning of EATS to reduce vehicle emissions. Summary of the Invention

[0006] The object of the present invention is to at least partially mitigate the disadvantages discussed above regarding known exhaust aftertreatment systems and to improve the pre-conditioning of at least a portion of exhaust aftertreatment systems.

[0007] According to a first aspect of the invention, an Exhaust Aftertreatment System (EATS) is provided for converting NOx emissions from exhaust gas from an engine. The EATS includes:

[0008] - Fluid passages, used to provide a fluid path for exhaust gas.

[0009] - A selective catalytic reduction (SCR) catalyst, arranged in a fluid channel, configured to store ammonia.

[0010] - An injector configured to inject a reducing agent to supply ammonia to the SCR catalyst, the injector being positioned upstream of the SCR catalyst.

[0011] - A fluid flow inducer configured to induce fluid flow in at least a portion of a fluid passage when the engine is off.

[0012] - A control device configured to pre-condition EATS by injecting a reducing agent into a fluid channel prior to engine start-up, and to deliver the reducing agent to the SCR catalyst via the induced fluid flow, thereby storing ammonia in the SCR catalyst.

[0013] Therefore, the SCR catalyst is pre-conditioned in an advantageous manner. That is, the SCR catalyst is pre-conditioned at least in terms of the increased ammonia storage within the SCR catalyst, thereby improving the conversion of NOx emissions in the exhaust gas during engine start-up. Typically, NOx emissions associated with cold start emissions are reduced because the SCR catalyst is pre-conditioned before engine start-up. As a result of engine cold starts, cold start emissions typically contain undesirable compounds (e.g., NOx, particulate matter, and CO or unburned HC) in the exhaust gas, and such cold start emissions can be reduced by pre-conditioning the EATS as described in this disclosure. Thus, cold start emissions can be reduced, and exhaust gas with reduced emissions can exit the EATS through the exhaust pipe. Typically, the engine is contained within the vehicle, and therefore, exhaust gas with reduced emissions can exit the EATS through the vehicle's exhaust pipe.

[0014] According to at least one example embodiment, the control device is further configured to pre-adjust the EATS to achieve a predetermined ammonia storage level in the SCR catalyst. By pre-adjusting the SCR catalyst to the predetermined ammonia storage level, the SCR catalyst can be brought closer to its normal operating conditions before engine start-up. Thus, at engine start-up, the SCR catalyst has an ammonia storage level closer to its normal operating conditions compared to a case where the SCR catalyst is not pre-adjusted to the predetermined ammonia storage level. The predetermined ammonia storage level may, for example, be an ammonia storage threshold level. According to at least one example embodiment, the control device is configured to determine the current ammonia storage level in the SCR catalyst and is configured to inject a reducing agent to meet the ammonia storage threshold level.

[0015] According to at least one example embodiment, pre-adjustment is performed up to 30 minutes before engine start. Therefore, sufficient pre-adjustment of EATS as described in this disclosure can be achieved. For example, pre-adjustment is performed up to 20 minutes or up to 10 minutes before engine start. Thus, for example, pre-adjustment is performed between 0 and 30 minutes before engine start (e.g., between 0 and 20 minutes, or between 0 and 10 minutes). According to another example, pre-adjustment is performed between 1 and 30 minutes before engine start (e.g., between 1 and 20 minutes, or between 1 and 10 minutes).

[0016] According to at least one example embodiment, at least said portion of the fluid channel undergoing flow induced by the fluid flow inducer includes a fluid path from the injector or from a reducing agent injection point in the fluid channel implemented by the injector to the SCR catalyst. Therefore, the induced fluid flow will at least deliver the injected reducing agent from the injector to the SCR catalyst. The fluid flow inducer may be referred to as a mass flow source or a fluid flow source.

[0017] It should be understood that "before the engine starts" means that the engine is not running, and therefore no exhaust flow from the engine passes through EATS during the pre-conditioning period. Therefore, the induced fluid flow is a fluid flow distinct from the exhaust flow.

[0018] According to at least one example embodiment, the injector is configured to inject a liquid reducing agent to supply ammonia to the SCR catalyst. Therefore, the control device is configured to pre-adjust EATS by injecting the liquid reducing agent into the fluid passage prior to engine start-up. Thus, a conventional type of reducing agent source can be readily injected into the fluid passage; the liquid reducing agent is, for example, urea. According to at least one example embodiment, the liquid reducing agent is anhydrous ammonia, ammonia water, an aqueous urea solution, or ammonia-containing diesel exhaust fluid.

[0019] According to at least one example embodiment, the injector is configured to inject a gaseous reducing agent to supply ammonia to the SCR catalyst. Therefore, the control device is configured to pre-regulate the EATS by injecting the gaseous reducing agent into the fluid passage prior to engine start-up. This facilitates the delivery of the reducing agent to the SCR catalyst via the induced fluid flow. The use of the gaseous reducing agent also promotes the absorption or storage of ammonia in the SCR, and / or requires less external heat to supply the SCR catalyst with the gaseous reducing agent.

[0020] According to at least one example embodiment, the injector is configured to inject a solid reducing agent to supply ammonia to the SCR catalyst. Therefore, the control device is configured to pre-condition the EATS by injecting the solid reducing agent into the fluid passage prior to engine start-up. Typically, such a solid reducing agent (e.g., in the form of a solid crystalline element) must be heated to provide the ammonia that the SCR catalyst can store.

[0021] According to at least one example embodiment, EATS further includes a heating device for heating the reducing agent, wherein the control device is configured to heat the reducing agent via the heating device.

[0022] Therefore, ammonia storage in the SCR catalyst is improved. For example, if a liquid or solid reducing agent is injected into a fluid channel, heating it typically causes the liquid or solid reducing agent to vaporize. The gaseous reducing agent or gaseous ammonia is more readily transported to the SCR catalyst through the induced fluid flow, and / or the gaseous reducing agent or gaseous ammonia also promotes the absorption or storage of ammonia in the SCR. The heating device is preferably arranged upstream or upstream of the SCR catalyst. Therefore, the heat supplied from the heating device is utilized efficiently. The heating device is typically configured to provide external heat to the reducing agent.

[0023] According to at least one example embodiment, the heating device is arranged in a fluid channel upstream of the injector to heat the induced fluid flow passing through the heating device, or the heating device is arranged to heat the reducing agent before the reducing agent is injected.

[0024] Therefore, at least two different alternative locations for providing heat to the reducing agent are provided. For example, in an embodiment where the heating device is arranged upstream of the injector in a fluid channel, the heating device may include a heated member arranged in the fluid channel such that the induced fluid flow is heated by passing through the heated member. The heated member may be, for example, a grid, a coil, or a plate. Thus, when the heated induced fluid flow heats the injected reducing agent, the injected reducing agent is indirectly heated by the heating device. Therefore, the injected reducing agent can be heated to evaporate and hydrolyze into ammonia. According to another example, in an embodiment where the heating device is arranged to heat the reducing agent before it is injected, the heating device may include a heated member arranged to contact the injector or any reducing agent dosage container fluidly connected to the injector. Thus, the reducing agent can be heated before it is injected into the fluid channel.

[0025] According to at least one example embodiment, the heating device includes an electric heating element or a burner.

[0026] Therefore, at least two different alternatives for heating the reducing agent are provided. In embodiments where the heating device includes an electric heating element, the heating element is configured to be heated by electricity. The electric heating element may include or be thermally connected to the aforementioned heated element. According to at least one example embodiment, the heated element includes a grid, grating, coil, or plate, configured to be heated by electricity guided through the grid, grating, coil, or plate. The electric heating element may be of another shape, for example, in the shape of a flat or curved heating sheet, or may include different types of heating elements, such as resistive foam. According to at least one example embodiment, the electric heating element is a positive temperature coefficient (PTC) based element. According to at least one example embodiment, the electric heating element is based on induction heating and may be referred to as an induction heating element. In embodiments where the heating device includes a burner, the burner may be configured to burn fuel to provide heat and may be thermally connected to the aforementioned heated element.

[0027] According to at least one example embodiment, the fluid flow inducer is a fan or a compressor.

[0028] A fan or compressor can be relatively easily arranged within a fluid channel to induce fluid flow, or it can be arranged outside the fluid channel and fluidly connected to it via a connecting channel. That is, in the latter case, the fan or compressor can be configured to induce fluid flow in a connecting channel, wherein the connecting channel is connected to the fluid channel to supply the induced fluid flow to at least a portion of the fluid channel. The fan or compressor can be easily and quickly started and easily and quickly shut down as desired. Furthermore, the control device can be configured to control the operation of the fan or compressor in a concise manner. Moreover, the level or volume of the induced fluid flow can be easily changed (increased or decreased) by the fan or compressor.

[0029] According to at least one example embodiment, the fluid flow inducer includes a compressed gas source and a valve configured to release compressed air from the compressed gas source into a fluid passage.

[0030] A compressed gas source and a valve are reliable means of providing the induced fluid flow. Furthermore, a relatively high level or high volume of the induced fluid flow in the fluid channel can be rapidly provided by opening the valve.

[0031] According to at least one example embodiment, the fluid flow inducer is arranged upstream of the injector.

[0032] Therefore, any reducing agent ejected from the injector can follow and be transported by the induced fluid flow. According to at least one example embodiment, the fluid flow inducer is arranged upstream of the heating device in the fluid channel. Thus, the induced fluid flow can be heated by the heating device before reaching the injection point of the reducing agent. Therefore, the induced fluid flow is configured such that it passes the heating device and the injection point of the reducing agent before reaching the SCR catalyst. The injector can, for example, be arranged at a predetermined distance from the heating device so that the heated induced fluid flow can heat any reducing agent ejected by the injector.

[0033] According to at least one example embodiment, EATS further includes an auxiliary heating device for heating the SCR catalyst, wherein the control device is further configured to heat the SCR catalyst via the auxiliary heating device.

[0034] Therefore, the SCR catalyst can be heated separately from the heating device configured as a heating reducing agent. This allows for further improvement in the pre-conditioning of EATS, as the SCR catalyst can be pre-conditioned in an advantageous manner. For example, by thermally pre-conditioning the SCR catalyst, it can be brought closer to its operating temperature before engine start-up. Furthermore, the absorption or storage of ammonia in the SCR process can be promoted by the thermally pre-conditioned SCR catalyst.

[0035] According to a second aspect of the invention, a method is provided to pre-regulate at least a portion of an exhaust aftertreatment system (EATS) configured to convert NOx emissions from exhaust gas from an engine, the EATS comprising: a fluid passage for providing a fluid path to the exhaust gas; and a selective catalytic reduction (SCR) catalyst disposed within the fluid passage, the SCR catalyst being configured to store ammonia. The method includes:

[0036] - Inject the reducing agent into the fluid channel, and

[0037] - Inducing fluid flow in at least a portion of the fluid path to deliver a reducing agent to the SCR catalyst, thereby storing ammonia in the SCR catalyst.

[0038] The effects and features of the second aspect of the invention are largely similar to those described above in conjunction with the first aspect of the invention. The embodiments mentioned with respect to the first aspect of the invention are largely compatible with the second aspect of the invention, some of which are illustrated below, and any advantageous effects are generally not repeated.

[0039] According to at least one example embodiment, the method is pre-conditioned to achieve a predetermined ammonia storage level in the SCR catalyst.

[0040] According to at least one example embodiment, the EATS includes: an injector configured to inject a reducing agent to provide ammonia to the SCR catalyst; and a fluid flow inducer configured to induce fluid flow, wherein the fluid flow inducer is arranged upstream of the injector. The injector and fluid flow inducer, and any embodiments thereof, are described in a first aspect of the invention.

[0041] According to at least one example embodiment, the method further includes heating a reducing agent.

[0042] According to at least one example embodiment, the EATS includes a heating device for heating a reducing agent, the heating device being arranged upstream of the injector in a fluid channel, and the method comprising heating the reducing agent by heating the induced fluid flow passing through the heating device and the injector, or wherein the heating device is arranged to heat the reducing agent, and the method comprises heating the reducing agent prior to injection. As described with respect to a first aspect of the invention, for embodiments in which the heating device is arranged upstream of the injector in a fluid channel, the heating device is generally configured to heat the induced fluid flow passing through the heating device, wherein the heated induced fluid flow heats the injected reducing agent.

[0043] According to a third aspect of the invention, a control device is provided for a vehicle including an Exhaust Aftertreatment System (EATS). The control device is configured to instruct the EATS of the first aspect of the invention to perform steps of the method according to the second aspect of the invention.

[0044] Therefore, the control device is configured to perform or implement at least some of the corresponding steps described in the method according to the second aspect of the invention. According to at least one example embodiment, the control device is configured to perform or implement method steps according to any embodiment mentioned with respect to the first aspect of the invention by instructing the EATS of the first aspect of the invention. The control device may be, for example, in or be included in the electronic control unit (ECU) of a vehicle.

[0045] According to a fourth aspect of the invention, a vehicle is provided. The vehicle includes an exhaust aftertreatment system (EATS) according to a first aspect of the invention or a control device according to a third aspect of the invention.

[0046] According to at least one example embodiment, the vehicle is a hybrid vehicle, which includes an electric motor for propelling the vehicle in addition to the engine.

[0047] Therefore, the operating time or power of the engine (e.g., a diesel engine or a hydrogen engine) can be reduced. Furthermore, for at least some vehicle operation, the engine can be shut off, and the vehicle can be propelled solely by the electric motor. Typically, the vehicle includes energy storage or conversion devices (e.g., batteries or fuel cells) to power the electric motor.

[0048] According to a fifth aspect of the invention, a computer program is provided, the computer program including a program code component including instructions to cause the EATS of the first aspect of the invention to perform the steps of the method according to the second aspect of the invention when the program is run on a computer.

[0049] According to a sixth aspect of the invention, a computer-readable medium carrying a computer program is provided, the computer program including program code components including instructions to cause the EATS of the first aspect of the invention to perform the steps of the method according to the first aspect of the invention when the program is run on a computer.

[0050] The effects and features of the third to sixth aspects of the present invention are largely similar to those described above in conjunction with the first and second aspects of the present invention. The embodiments mentioned with respect to the first and second aspects of the present invention are largely compatible with the third to sixth aspects of the present invention.

[0051] The order of the method steps described in the second aspect of the invention and implemented in some other aspects of the invention is not limited to the order described in this disclosure. One or more steps may be interchanged or occur in a different order without departing from the scope of the invention. However, according to at least one example embodiment, the method steps are performed in the sequential order described in the second aspect of the invention.

[0052] According to at least one exemplary embodiment, applicable to any of the first to sixth aspects of the invention, an EATS is configured for converting NOx emissions from exhaust gases from a vehicle (e.g., a heavy-duty truck) engine. The EATS can be used to clean exhaust gases from various types of engines, such as diesel or hydrogen engines. For example, this EATS can be used to clean exhaust gases by converting NOx emissions from exhaust gases from internal combustion engines based on CNG (compressed natural gas), LPG (liquefied pressurized gas), DME (dimethyl ether), and / or H2 (hydrogen).

[0053] According to at least one example embodiment, the EATS is configured for converting NOx emissions from the exhaust gas of a vehicle's hydrogen engine. In such an embodiment, the EATS may further include a particulate filter configured to filter particles from the exhaust gas. This particulate filter is advantageously positioned upstream of the SCR catalyst.

[0054] Further advantages and features of this disclosure are disclosed and discussed in the following description and accompanying drawings. Attached Figure Description

[0055] Referring to the accompanying drawings, a more detailed description of embodiments of the present invention, cited as examples, follows.

[0056] In these diagrams:

[0057] Figure 1 This is a schematic side view of a vehicle including an engine, EATS, and control equipment according to an exemplary embodiment of the present invention;

[0058] Figure 2 This illustrates example embodiments applicable to the present invention. Figure 1 More detailed setup diagrams illustrating schematic examples of the engine, EATS, and control equipment; and

[0059] Figure 3 This is a flowchart illustrating the steps of a method according to an exemplary embodiment of the present invention. Detailed Implementation

[0060] refer to Figure 1 The present disclosure discloses a vehicle 1 (implemented herein as a heavy-duty truck 1) for which the exhaust aftertreatment system EATS20 of the type disclosed herein is advantageous. However, EATS20 can also be implemented in other types of vehicles, such as buses, light trucks, passenger cars, marine applications, etc., with similar engine systems. Figure 1 Vehicle 1 is a hybrid vehicle 1, comprising an engine 15 and an electric motor 22. The engine 15 is a diesel engine 15. The diesel engine 15 is powered by diesel fuel, which is typically housed in a fuel tank (not shown), and the electric motor 22 is powered by electricity supplied from at least one energy storage or conversion device (e.g., a battery or fuel cell). The diesel engine 15 and the electric motor 22 are typically arranged and configured to propel vehicle 1 independently via other parts of the powertrain (e.g., a transmission, driveshaft, and wheels (not shown in detail)) separately coupled to it. That is, vehicle 1 can be propelled by the diesel engine 15 alone, by the electric motor 22 alone, or by both the diesel engine 15 and the electric motor 22 together. Engine 15 and EATS 20 can be collectively referred to as the engine system.

[0061] exist Figure 1In this embodiment, EATS 20 is configured to reduce emissions in the exhaust gas from engine 15. EATS 20 includes: a fluid passage 40 for providing a fluid path for the exhaust gas from engine 15; and a selective catalytic reduction (SCR) catalyst 32 disposed within the fluid passage 40. The SCR catalyst 32 is disposed and configured to convert nitrogen oxides (also known as NOx) into diatomic nitrogen (N2) and water (H2O) (and possibly carbon dioxide CO2) with the aid of a catalyst. An injector 34 is configured to inject a reducing agent, such as anhydrous ammonia, ammonia solution, or urea solution, and is disposed upstream of the SCR catalyst 32. The injected reducing agent provides ammonia, which is adsorbed onto the catalyst in the SCR catalyst 32 and promotes the conversion of NOx in the SCR catalyst 32. Thus, the SCR catalyst 32 is configured to store ammonia. EATS 20 also includes: a fluid flow inducer 56 configured to induce fluid flow in at least a portion of the fluid passage 40 when the engine is off; and a control device 17 (control unit 17) configured to pre-condition EATS 20 by injecting a reducing agent into the fluid passage 40 before engine startup and to deliver the reducing agent to the SCR catalyst via the induced fluid flow to store ammonia in the SCR catalyst. Thus, Figure 1 The EATS20 is configured to pre-adjust before engine start, which will refer to Figures 2 to 3 Further description.

[0062] Figure 2 yes Figure 1 A schematic diagram of the EATS20 is shown in more detail and includes various optional components and alternatives. Figure 2 EATS20 includes references Figure 1 The fluid passage 40, SCR catalyst 32, and injector 34 are described. Furthermore, EATS 20 includes DOC 30 and a particulate filter, which in this embodiment is DPF 31. DOC 30 is disposed upstream of DPF 31 and configured to convert carbon monoxide and hydrocarbons into carbon dioxide. DPF 31 is disposed upstream of SCR catalyst 32 and is arranged and configured to remove particulate matter, i.e., diesel particulate matter or soot, from the exhaust of diesel engine 15.

[0063] During the initial operation of a vehicle (e.g., until the engine and EATS have reached operating temperatures), emissions from the EATS (e.g., emissions per distance traveled, or emissions per unit operating time) are typically higher than emissions when the engine and EATS have reached operating temperatures. These emissions are known as cold-start emissions, and they typically include undesirable compounds (e.g., NOx, particulate matter, and CO or unburned HC) in the exhaust gas emitted from the EATS due to engine cold starts. To avoid or at least reduce such cold-start emissions, the EATS can be pre-conditioned before engine start. That is, at least a portion of the EATS can be prepared in a manner that reduces emissions during the initial engine operation.

[0064] In order to achieve at least one pre-adjustment of EATS20, Figure 2 The EATS20 includes fluid flow inducers 56 and 58, which are configured to induce fluid flow in at least a portion of the fluid passage 40 when the engine is off. Figure 2 The diagram illustrates two distinct fluid flow inducers 56 and 58, requiring only one to induce the fluid flow. As a first option, the first fluid flow inducer 56 is arranged upstream of the injector 34 in the fluid passage 40 and is configured to induce fluid flow in at least a portion of the fluid passage 40 downstream of the first fluid flow inducer 56 when the engine 15 is off. The first fluid flow inducer 56 may be, for example, a compressor or a fan. As a second option, the second fluid flow inducer 58 includes a compressed gas source 60 and a valve 61 configured to release compressed air from the compressed gas source 60 into the fluid passage 40. Thus, the second fluid flow inducer 58 is configured to induce fluid flow in at least a portion of the fluid passage 40 downstream of the valve 61 (or any connecting passage fluidly connecting the valve 61 to the fluid passage 40). Therefore, in both the first and second options, the fluid flow inducers 56 and 58 are configured to induce fluid flow upstream of the injector 34 before engine startup.

[0065] Figure 2 The control device 17 of EATS20 is configured to at least control the preconditioning of the SCR catalyst 32 by injecting a reducing agent into the fluid passage 40 using injector 34, and to deliver the injected reducing agent into the SCR catalyst 32 by fluid flow induced by fluid flow inducers 56, 58, so as to store ammonia in the SCR catalyst 32. Thus, the desired preconditioning of EATS20 is achieved, thereby reducing undesirable NOx emissions from, for example, cold starts of engine 15.

[0066] Optionally, EATS20 also includes heating devices 50, 52, and 53 for heating the reducing agent. Figure 2 The diagram shows three different heating devices 50, 52, and 53, of which only one is needed to heat the reducing agent. In a first alternative, the first heating device 50 is arranged upstream of the injector 34 in the fluid channel 40. Figure 2 As shown, the first heating device 50 is arranged immediately upstream of the injector 34, with no other EATS components between them. For example, the fluid flow distance between the first heating device 50 and the injector 34 or the point where the reducing agent is injected into the fluid channel 40 is 0.1 to 1 m. Therefore, the first heating device 50 can heat the induced fluid flow passing through the first heating device 50. In a second alternative that can be used alone or in combination with the first alternative, the second heating device 52 is arranged upstream of the injector 34 in the fluid channel 40. Figure 2 As shown, the second heating device 52 is arranged immediately downstream of the fluid flow inducers 56, 58 (or the point where the induced fluid flow is applied to the fluid channel 40), for example, without any other EATS components between them. For example, the fluid flow distance between the second heating device 52 and the fluid flow inducers 56, 58 (or the point where the induced fluid flow is applied to the fluid channel 40) is 0.1 to 1 m. Therefore, the second heating device 52 can heat the induced fluid flow passing through it. Preferably, the first heating device 50 and / or the second heating device 52 are electric heating elements. As previously mentioned, the first heating device 50 and the second heating device 52 can be combined to enhance the heating of the induced fluid flow.

[0067] In a third alternative that can be used alone or in combination with the first and / or second alternatives, the third heating device 53 is arranged to heat the reducing agent before it is sprayed. Figure 2 As shown, the third heating device 53 is arranged adjacent to or thermally connected to the injector 34. For example, the third heating device 53 may be in direct contact with the injector 34 or any reducing agent dosage container fluidly connected to the injector 34. Therefore, the third heating device 53 can directly heat the reducing agent before it is injected into the fluid channel 40. For example, the reducing agent may be heated and evaporated before it is injected into the fluid channel 40. The third heating device 53 may be an electric heating element or a burner. In the burner, combustion of, for example, HC is achieved to generate heat. As previously described, the first, second, and / or third heating devices 50, 52, 53 may be combined to enhance the heating of the reducing agent.

[0068] Each of heating devices 50, 52, and 53 may, for example, include a grid or grille, or a coil or plate, configured to be heated by electricity directed through said grid, grille, coil, or plate. At least one of heating devices 50, 52, and 53 may be of another shape, for example, in the shape of a flat or curved heating sheet, or may include different types of heating elements, such as resistive foam. At least one of heating devices 50, 52, and 53 may be an element based on a positive temperature coefficient (PTC), or may be based on induction heating and referred to as an induction heating element.

[0069] Accordingly, Figure 2 The control device 17 of the EATS20 can be configured to heat the reducing agent via heating devices 50, 52, and 53. Therefore, the control device 17 is configured to initiate operation of the first, second, and / or third heating devices 50, 52, and 53 to heat the reducing agent, whether indirectly (i.e., via the induced fluid flow) by the first and second heating devices 50 and 52, or directly by the third heating device 53. Thus, the desired pre-conditioning of the EATS20 is achieved, thereby reducing undesirable NOx emissions from, for example, cold starts of the engine 15.

[0070] Turn Figure 3 The flowchart schematically illustrates the process for pre-adjusting EATS (such as...). Figure 1 and Figure 2 The steps of at least a portion of the method of EATS 20. Thus, the EATS is configured to at least convert NOx emissions from exhaust gas from an engine (e.g., engine 15). The EATS includes: a fluid passage for providing a fluid path for the exhaust gas; and a selective catalytic reduction (SCR) catalyst arranged in the fluid passage, for example, corresponding to… Figure 1 and Figure 2 The fluid channel 40 and the SCR catalyst 32 are configured to store ammonia.

[0071] In step S1, pre-adjustment of at least the aforementioned portion of the EATS begins. Pre-adjustment S1 is initiated when the engine is off, thus no exhaust flows through the EATS. Step S1 may be performed, for example, up to 30 minutes before engine startup.

[0072] In step S10, the reducing agent is injected into the fluid channel. For example, the reducing agent can be injected (e.g., via a reference). Figure 1 and Figure 2 The injector 34) is used to inject the reducing agent. The reducing agent provides ammonia to the SCR catalyst.

[0073] In optional step S20, the injected reducing agent is heated. Alternatively, in optional step S5, the reducing agent is heated before being injected into the fluid channel S10. Thus, the reducing agent can be heated before being injected and / or after being injected into the fluid channel. For example, the reducing agent is heated by a heating device (e.g., reference...). Figure 1 and Figure 2 Heating is achieved by the first, second, and / or third heating devices 50, 52, and 53.

[0074] In step S30, fluid flow is induced in at least a portion of the fluid path to deliver the reducing agent to the SCR catalyst, thereby storing ammonia in the SCR catalyst. Thus, fluid flow is induced during the engine-off state when no exhaust flows through the EATS. This fluid flow can be induced by a fluid flow inducer (e.g., reference...). Figure 1 and Figure 2 The first fluid flow inducer 56 or the second fluid flow inducer 58 induces the flow. Therefore, the fluid flow inducer is arranged upstream of the injector.

[0075] In embodiments where the reducing agent is heated (S5, S20), the induced fluid flow delivers the heated reducing agent to the SCR catalyst. In embodiments where the injected reducing agent is heated by a heating device, this heating device may be arranged in the fluid channel upstream of the injector or upstream of the point where the reducing agent is injected into the fluid channel. Furthermore, the portion of the fluid path subject to the induced fluid flow typically includes the heating device and the injector or the point where the reducing agent is injected into the fluid channel, such that the injected reducing agent is heated by the induced fluid flow passing through the heating device and the injector. Alternatively, the reducing agent may be heated by the heating device before injection. Thus, the heated reducing agent is injected into the fluid channel and further delivered to the SCR catalyst by the induced fluid flow.

[0076] In optional step S40, it is determined whether a predetermined ammonia storage level in the SCR catalyst has been reached. In response to determining that the predetermined ammonia storage level in the SCR catalyst has been reached, pre-conditioning S50 is stopped. However, in response to determining that the predetermined ammonia storage level in the SCR catalyst has not yet been reached, the pre-conditioning is restarted by returning to step S1 (or alternatively, by optional step S5, by heating the reducing agent before injection, or by injecting the reducing agent into the fluid channel S10).

[0077] By reference Figure 3 The method described (at least steps S10 and S30) pre-adjusts EATS with respect to at least the increased ammonia storage in the SCR catalyst, thereby improving the conversion of NOx emissions in the exhaust gas after engine start-up.

[0078] According to at least one example embodiment, the following is performed continuously. Figure 3 The steps of the method described herein. Thus, for example, a portion of the reducing agent is heated in step S5 before being injected into the fluid channel, while another portion of the heated reducing agent is injected into the fluid channel in step S10, and yet another portion of the heated reducing agent is delivered to the SCR catalyst in step S30 via the induced fluid flow (the heated portion). It should be noted that the naming of the steps is not necessarily specific, but rather, according to at least one example embodiment, may relate to the order in which these steps are performed. Therefore, the order of these steps may differ from that explained herein unless explicitly dependent on each other.

[0079] It should be understood that the present invention is not limited to the embodiments described above and shown in the accompanying drawings; rather, those skilled in the art will recognize that many changes and modifications can be made within the scope of the appended claims. The present invention is not limited to a particular type of engine system and / or EATS. For example, EATS20 or similar EATS can be used to clean exhaust gases from engines other than diesel engines. For example, EATS can be used to clean exhaust gases by converting NOx emissions from exhaust gases from internal combustion engines that use CNG (compressed natural gas), LPG (liquefied pressurized gas), DME (dimethyl ether), and / or H2 (hydrogen) as fuel. Therefore, the engine system may include another internal combustion engine different from a diesel engine, such as a hydrogen engine.

[0080] Furthermore, by studying the accompanying drawings, the disclosure, and the appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments when practicing the claimed inventive concept. In the claims, the word "comprising..." does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plural. The fact that certain measures are enumerated in mutually different dependent claims does not imply that combinations of these measures cannot be advantageously used.

Claims

1. An exhaust aftertreatment system, EATS, (20) for converting NOx emissions in exhaust gas from an engine (15), the EATS comprising: a fluid passage (40) for providing a fluid path for the exhaust gas, a selective catalytic reduction, SCR, catalyst (32) arranged in the fluid passage, the SCR catalyst being configured to store ammonia, an injector (34) configured to inject a reducing agent for providing ammonia to the SCR catalyst, the injector being arranged upstream of the SCR catalyst, a fluid flow inducer (56, 58) configured to induce a fluid flow in at least a portion of the fluid passage when the engine is off, a control device (17) configured to pre-condition the EATS by injecting the reducing agent into the fluid passage prior to engine start and to transport the reducing agent into the SCR catalyst by the induced fluid flow, thereby storing ammonia in the SCR catalyst, the EATS further comprising an electric heating device for heating the reducing agent, the control device being configured to heat the reducing agent by the electric heating device, wherein the electric heating device is arranged in the fluid passage immediately upstream of the injector, without other EATS components between the electric heating device and the injector.

2. The EATS of claim 1, wherein, The heating device (50, 52, 53) comprises an electric heating element or a burner.

3. The EATS of any one of claims 1-2, wherein, The fluid flow inducer (56) is a fan or a compressor.

4. The EATS of any one of claims 1-3, wherein, The fluid flow inducer (58) comprises a source (60) of compressed gas and a valve (61) configured to release compressed air from the source of compressed gas into the fluid passage.

5. The EATS of any one of claims 1-3, wherein, The fluid flow inducer (56, 58) is arranged in the fluid passage upstream of the injector.

6. A method for pre-conditioning at least a portion of an exhaust aftertreatment system, EATS, (20) configured to convert NOx emissions in exhaust gas from an engine (15), the EATS comprising: a fluid passage (40) for providing a fluid path for the exhaust gas, and a selective catalytic reduction, SCR, catalyst (32) arranged in the fluid passage, the SCR catalyst being configured to store ammonia, the EATS further comprising an electric heating device for heating the reducing agent, the electric heating device being arranged in the fluid passage immediately upstream of an injector, without other EATS components between the electric heating device and the injector, the method comprising: injecting (S10) a reducing agent into the fluid passage, inducing a fluid flow (S30) in at least a portion of the fluid path to transport the reducing agent into the SCR catalyst, thereby storing ammonia in the SCR catalyst, and heating the reducing agent using the electric heating device.

7. The method of claim 6, wherein, The pre-conditioning is performed to reach a predetermined ammonia storage level in the SCR catalyst. The EATS further comprises an electric heating device for heating the reducing agent, the control device being configured to heat the reducing agent by the electric heating device, wherein the electric heating device is arranged in the fluid passage immediately upstream of the injector, without other EATS components between the electric heating device and the injector. The heating device (50, 52, 53) comprises an electric heating element or a burner. The fluid flow inducer (56) is a fan or a compressor. The fluid flow inducer (58) comprises a source (60) of compressed gas and a valve (61) configured to release compressed air from the source of compressed gas into the fluid passage. The fluid flow inducer (56, 58) is arranged in the fluid passage upstream of the injector. a fluid passage (40) for providing a fluid path for the exhaust gas, and a selective catalytic reduction, SCR, catalyst (32) arranged in the fluid passage, the SCR catalyst being configured to store ammonia, the EATS further comprising an electric heating device for heating the reducing agent, the electric heating device being arranged in the fluid passage immediately upstream of an injector, without other EATS components between the electric heating device and the injector, the method comprising: injecting (S10) a reducing agent into the fluid passage, inducing a fluid flow (S30) in at least a portion of the fluid path to transport the reducing agent into the SCR catalyst, thereby storing ammonia in the SCR catalyst, and heating the reducing agent using the electric heating device. The pre-conditioning is performed to reach a predetermined ammonia storage level in the SCR catalyst.

8. The method of any one of claims 6-7, wherein, The EATS comprises an injector (34) configured to inject the reducing agent for providing ammonia to the SCR catalyst, and a fluid flow inducer (56, 58) configured to induce an induced fluid flow, and wherein the fluid flow inducer is arranged upstream of the injector in the fluid passage.

9. A control device (17) for a vehicle (1) comprising an exhaust aftertreatment system, EATS, (20), the control device being configured to instruct the EATS according to any one of claims 1-5 to perform the steps of the method according to any one of claims 6-8.

10. A vehicle (1) comprising an exhaust aftertreatment system, EATS, (20) according to any one of claims 1-5 or a control device according to claim 9.

11. A computer readable medium carrying a computer program comprising program code means comprising instructions to cause the EATS (20) according to any one of claims 1-5 to perform the steps of the method according to any one of claims 6-8 when said program is run on a computer.

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