Exhaust aftertreatment unit for cleaning exhaust gases

Abstract

To enable easy access to an electric heating element and maintenance or exchange of the same.SOLUTION: An exhaust aftertreatment unit includes: an emission reducing module being a diesel particulate collection filter DPF 30A and / or a diesel oxidation catalyst DOC 30B; a selective catalyst reduction SCR catalyst 32; an electrical heating element 38 arranged upstream of the emission reducing module; a casing 40 housing at least the emission reducing module and the electrical heating element 38; and a service lid 44 removably arranged to cover a service opening 42 of the casing 40, the emission reducing module being accessible through the inspection opening 42. The electrical heating element 38 is removably arranged relative the casing 40 and is arranged accessible upon removal of the service lid 44 and the emission reducing module.SELECTED DRAWING: Figure 3

Description

Technical Field

[0002]

[0001] The present invention relates to an exhaust aftertreatment unit for cleaning exhaust gas. Furthermore, the present invention relates to a method for handling a vehicle exhaust aftertreatment unit, an electric heating element used in the exhaust aftertreatment unit, and a vehicle comprising the exhaust aftertreatment unit.

Background Art

[0002] Vehicles typically comprise an engine for propelling the vehicle. The engine is powered by various means, such as liquid or gaseous fuel in an internal combustion engine, or electrical power in an electric machine. Furthermore, there are also hybrid solutions where the vehicle is propelled by both an internal combustion engine and an electric machine.

[0003] When the engine is a combustion engine, for example a diesel engine, it is common for the vehicle to comprise an exhaust aftertreatment system EATS for treating the emissions from the engine. An EATS for a diesel engine typically comprises a diesel oxidation catalyst DOC, a diesel particulate filter DPF, and a selective catalytic reduction SCR catalyst. A reducing agent, such as a urea or ammonia-containing substance, is injected upstream of the SCR catalyst, and the action of the catalyst promotes the conversion of nitrogen oxides, also called NOx, into diatomic nitrogen N2, water, and optionally (depending on the choice of reducing agent) carbon dioxide CO2. The then purified or at least emissions-reduced exhaust gas is discharged from the EATS and the vehicle through the vehicle's exhaust pipe. Other types of engines that produce emissions similar to those of a diesel engine can also utilize the same or a similar EATS.

[0004] Government regulations, along with the relentless demand for improved vehicle fuel efficiency, suggest the need for more efficient operation of EATS (Exhaust Emission Control System). For example, EATS must rapidly heat up even at extremely low loads when exhaust gas temperatures are low, and have high conversion efficiency. Furthermore, the need for extremely efficient engines to meet stringent CO2 requirements necessitates lower exhaust gas temperatures and higher NOx levels emitted from the engine, requiring the injection of large amounts of reducing agent upstream of the SCR catalyst. Moreover, when using urea as a reducing agent, it is necessary to heat the urea to evaporate and produce ammonia through hydrolysis. If the temperature is too low, there is a significant risk of crystal and deposit formation, which reduces the effectiveness of EATS.

[0005] To address the low temperature of exhaust gases, electric heating elements may be used to heat the exhaust gases and thereby reduce associated drawbacks. However, adding electric heating elements to the EATS increases the complexity of the system and / or adds components that may lead to failures and require maintenance or replacement. Failures of EATS components often require time-consuming inspections that involve costly vehicle downtime. Furthermore, component failures that lead to component replacement or even replacement of the entire EATS are undesirable from an environmental perspective.

[0006] Therefore, an improved EATS aimed at mitigating the above-mentioned shortcomings is needed in this industry. [Overview of the project] [Problems that the invention aims to solve]

[0007] The object of the present invention is to provide an improved exhaust aftertreatment unit that at least partially mitigates the aforementioned drawbacks of well-known exhaust aftertreatment systems. [Means for solving the problem]

[0008] According to a first aspect of the present invention, an exhaust gas aftertreatment unit for purifying exhaust gas is provided. The exhaust gas aftertreatment unit is - An emission reduction module which is a diesel particulate filter (DPF) and / or a diesel oxidation catalyst (DOC), - Selective catalytic reduction SCR catalyst, - An electric heating element located upstream of the emission reduction module, - A casing that houses at least an emissions reduction module and an electric heating element, - An inspection cover that is removable and positioned to cover the inspection opening of the casing, and through the inspection opening, is an access point to the emissions reduction module, Equipped with, The electric heating element is positioned to be removable from the casing and accessible when the inspection cover and the emissions reduction module are removed.

[0009] This allows for easy access to the electric heating element in the exhaust aftertreatment unit, enabling its maintenance or replacement. Thus, an exhaust aftertreatment unit is provided with a simple configuration that allows for easy access to the electric heating element while mitigating the disadvantage of the exhaust gas being at a low temperature due to the electric heating element. This provides an improved exhaust aftertreatment unit in which exhaust gas emissions can be removed very efficiently by heating the exhaust gas with at least the electric heating element, while reducing the additional complexity of the electric heating element by allowing easy access when removing the inspection cover. Furthermore, by positioning the electric heating element upstream of the emissions reduction module, the emissions reduction module can be heated by the electric heating element. Additionally or alternatively, any other components (e.g., the secondary catalyst described later) positioned between the emissions reduction module and the electric heating element can also be heated by the electric heating element.

[0010] According to at least one exemplary embodiment, the emissions reduction module comprises a first end portion (or downstream end portion) having a first end face (or downstream surface) facing downstream of the flow path within the exhaust aftertreatment unit, and a second end portion (or upstream end portion) on the opposite side having a second end face (or upstream surface) facing upstream of the flow path, wherein the electric heating element is positioned upstream of the second end portion. For example, the electric heating element faces the second end face. According to at least one exemplary embodiment, the inspection cover is positioned facing the first end portion and the first end face. That is, when the emissions reduction module is positioned inside the casing, the first end portion is positioned facing the inspection cover, and the second end portion is positioned upstream of the first end portion.

[0011] According to at least one exemplary embodiment, the emissions reduction module, i.e., DPF and / or DOC, is removably located inside the casing and can pass through an inspection opening when the inspection cover is removed. It should be noted that the emissions reduction module may comprise a mounting member that is incorporated into and securely attached to the casing and an insert member that is removably located within the mounting member. In such embodiments, the insert member is removably located inside the casing and can pass through an inspection opening when the inspection cover is removed. Thus, throughout this specification, the emissions reduction module refers to the emissions reduction module or an insert member of the emissions reduction module.

[0012] According to at least one exemplary embodiment, the electric heating element is located on the opposite side of the inspection cover of the emissions reduction module. That is, the inspection cover and the electric heating element are located on both sides of the emissions reduction module. Such a configuration is advantageous because the electric heating element and any electrical connections used to supply power to the electric heating element are located away from the inspection cover and inspection opening, for example, when the emissions reduction module is removed. That is, since the emissions reduction module is located in a removable manner relative to the casing and is accessible when the inspection cover is removed, the emissions reduction module can be accessed and / or removed from the casing without interference with the electric heating element. For example, if only the emissions reduction module is to be serviced or replaced, the emissions reduction module can be accessed and / or removed from the casing independently of the electric heating element.

[0013] According to at least one exemplary embodiment, (for example, during use of the exhaust aftertreatment unit) the electric heating element is located inside the casing, and (for example, during maintenance of the exhaust aftertreatment unit) after the emissions reduction module and inspection cover have been removed, the electric heating element can be removed from the casing through an inspection opening. This allows for easy access to the electric heating element through the inspection opening. For example, maintenance of the electric heating element can be performed through the inspection opening, or maintenance of the electric heating element can be performed on the removed electric heating element. Thus, and according to at least one exemplary embodiment, the electric heating element can be removed from the casing through an inspection opening for maintenance and / or replacement of the electric heating element. Thus, the inspection cover serves both as an inspection cover for the electric heating element and as an inspection cover for the emissions reduction module.

[0014] The emission reduction module is a diesel particulate filter (DPF) configured to remove particulate matter, such as diesel particulate matter or soot, from the exhaust gas and / or a diesel oxidation catalyst (DOC) configured to convert carbon monoxide and hydrocarbons into carbon dioxide. Thus, according to at least one exemplary embodiment, the emission reduction module is a combined DPF / DOC, for example, in which the DOC is located upstream of the DPF. According to at least one exemplary embodiment, the emission reduction module is a DPF. According to at least one exemplary embodiment, the emission reduction module is a DOC. When the emission reduction module is a combined DPF / DOC, the DPF and DOC do not necessarily have to be combined in the same unit, but may be contained in separate units, in which case these separate units may be separated from each other by a gap. Thus, the exhaust gas enters the DOC, emission reduction takes place in the DOC, and then exits the DOC into the gap. After this, the exhaust gas enters the DPF from the gap, emission reduction takes place in the DPF, and then exits the DPF. According to one exemplary embodiment, two separate units may be connected to each other, for example, by a connecting element extending from the DPF to the DOC through a gap. However, according to at least one exemplary embodiment, the DPF and DOC of a combined DPF / DOC are contained within the same unit.

[0015] According to at least one exemplary embodiment, the casing comprises a mounting socket for housing an emissions reduction module and an electric heating element.

[0016] This allows the emission reduction module and the electric heating element to be satisfactorily positioned inside the casing. During use of the electric heating element, it is preferable that it be positioned and configured to maintain the temperature inside the mounting socket between 180°C and 300°C.

[0017] According to at least one exemplary embodiment, the emissions reduction module and the electric heating element are detachably positioned relative to the mounting socket. Therefore, the electric heating element may be detachably positioned relative to the casing by being detachably positioned relative to the mounting socket. Similarly, the emissions reduction module may be detachably positioned relative to the mounting socket. It is preferable that it be positioned in a way that allows it to be removed from the casing.

[0018] The mounting socket is preferably positioned inside the casing such that the inspection cover faces the opening or port of the mounting socket. Therefore, when the inspection cover is removed, the emissions reduction module can be removed from the casing and mounting socket through the opening or port of the mounting socket, and then through the inspection opening. That is, the inspection opening and the opening or port of the mounting socket are preferably coaxial. This allows access to the electric heating element through the inspection opening and the opening or port of the mounting socket. Subsequently, the electric heating element can be removed from the casing and mounting socket through the opening or port of the mounting socket, and then through the inspection opening.

[0019] According to at least one exemplary embodiment, the geometric shape of the mounting socket is adapted to the geometric shape of the emissions reduction module. This allows the emissions reduction module to be efficiently positioned inside the mounting socket. According to at least one exemplary embodiment, the mounting socket is geometrically shaped in an open cylindrical or tubular form. Similarly, the emissions reduction module is preferably shaped in a cylindrical form. According to at least one exemplary embodiment, the geometric shape of the electric heating element may be adapted to the geometric shape of the mounting socket. For example, the electric heating element may be geometrically shaped in a round or circular form, or, for example, in a coil form.

[0020] According to at least one exemplary embodiment, the mounting socket is incorporated into the casing and securely attached. Note that the mounting socket is a mounting component of the emission reduction module described above. Alternatively, the mounting component of the emission reduction module may be incorporated into the mounting socket of the casing and securely attached.

[0021] According to at least one exemplary embodiment, the electric heating element is powered by at least one electrical connection extending from the outer surface of the casing into an upstream mounting socket of the electric heating element.

[0022] This provides a means to access the emissions reduction module without interfering with the electric heating element and / or to remove the emissions reduction module from the casing. The outer surface of the casing through which the electrical connections pass is sometimes referred to as the outer surface of the casing, and is typically located on the side opposite the inspection cover of the casing. Thus, and according to at least one exemplary embodiment, the inspection cover and the outer surface of the casing (through which the electrical connections pass) are located on both sides of the casing. By extending the electrical connections through the outer surface of the casing into the upstream mounting socket of the electric heating element, the electrical connections do not interfere with or interact with the inspection cover and / or inspection opening. This provides a favorable means for supplying power to the electric heating element. Typically, at least one electrical connection passes through at least the outer surface of the casing; that is, at least one electrical connection extends from outside the casing through the outer surface of the casing into the upstream mounting socket of the electric heating element. Typically, the casing has a specific wall thickness, which is defined as the distance from the outer surface (or outer portion) of the casing to the corresponding inner surface (or inner portion) of the casing. This inner surface or inner portion typically faces the mounting socket and the electrically heated element located within the mounting socket.

[0023] According to at least one exemplary embodiment, the electrical connection is detachably mounted on the outer surface of the casing.

[0024] According to at least one exemplary embodiment, at least one electrical connection part includes at least two electrical connection lines, namely a power line (or phase line) and a neutral line, and is configured such that when power is supplied to the electric heating element, current flows between the power line and the neutral line.

[0025] According to at least one exemplary embodiment, the exhaust aftertreatment unit further includes at least one guide element for guiding an electrical connection part through the outer surface of the casing, and the electric heating element and at least one electrical connection part are removably attached to the guide element, or the electric heating element, at least one electrical connection part, and the guide element are removably attached to the outer surface of the casing.

[0026] Thereby, at least two solutions are provided to enable the electric heating element to be removably disposed with respect to the casing while sufficiently extending the electrical connection part from the outside of the casing to the electric heating element inside the casing.

[0027] According to at least one exemplary embodiment, the electric heating element and at least one electrical connection part are removably disposed with respect to the casing by a mounting structure disposed on the outer surface of the casing. Thereby, the electric heating element and at least one electrical connection part can be separated from the casing by accessing the mounting structure on the outer surface of the casing. Accordingly, the method may include separating the electric heating element from the casing by the mounting structure on the outer surface of the casing.

[0028] According to at least one exemplary embodiment, the electrical connection part has airtightness. For example, at least one guide element provides airtight characteristics.

[0029] According to at least one exemplary embodiment applicable to at least one electrical connection detachably attached to an electrically heating element and a guide element, the guide element comprises at least one tube (or one tube per electrical connection wire, e.g., two tubes) penetrating the outer surface of the casing. The at least one tube may be mounted and securely attached to the outer surface of the casing, for example, by an end plate welded to the outer surface. One end of the at least one tube has threads, and a nut (constituting the mounting structure) is fitted onto the threads. The nut may, if possible, have one or more inner cones that interact with the electrical connection by compression (i.e., by so-called compression fitting). When the electrical connection is removed from the tube, the compression is released by simply removing the nut from the tube.

[0030] According to at least one exemplary embodiment applicable to an electrically heated element, at least one electrical connection, and a guide element detachably mounted to the outer surface of a casing, the guide element comprises at least one flange, which is typically securely attached to the electrical connection of the electrically heated element. The flange may have a plurality of screw holes and be detachably mounted to the outer surface of the casing by screws (constituting the mounting structure) that are screwed into the screw holes. When removing the guide element (as well as the electrical connection and the electrically heated element) from the outer surface of the casing, the guide element can be detached from the casing simply by unscrewing the screws from the screw holes. Optionally, a gasket may be used.

[0031] According to at least one exemplary embodiment, the electric heating element is removably positioned at at least one electrical connection. This provides an alternative method for removing the electric heating element from the casing. In such an embodiment, the electrical connection and any guide elements are securely mounted to the casing, and the electric heating element is removably positioned at the electrical connection by, for example, screws or other fastening means. Thus, the electric heating element is typically separated from the electrical connection inside the mounting socket. According to at least one exemplary embodiment, the electric heating element is integrated within the outer surface of the casing.

[0032] According to at least one exemplary embodiment, the mounting socket extends along its long axis, and at least one electrical connection extends inward from the mounting socket in a direction along or parallel to the long axis.

[0033] This facilitates the removal of the electric heating element from the casing because the electrical connection extends in the same direction as the removal of the electric heating element. That is, the mounting socket extends along its long axis, and the electric heating element is removed from the casing by passing it through the mounting socket in a direction along or parallel to its long axis. Therefore, the fact that the electrical connection extends in the same direction as the removal of the electric heating element from the casing facilitates the removal of the electric heating element from the casing. For example, the risk of the electrical connection interfering with the inner surface of the mounting socket and potentially becoming immobile relative to the mounting socket is reduced. Similarly, the emissions reduction module is removed from the casing by passing it through the casing in a direction along or parallel to its long axis. Focusing on the first and second end portions of the emissions reduction module, the module is configured to be removed axially from the mounting socket with the first end portion first. Similarly, the emission reduction module is configured to be inserted axially into the mounting socket with the second end portion leading.

[0034] According to at least one exemplary embodiment, the electric heating element is attached to the emissions reduction module and is removably mounted to the casing together with the emissions reduction module.

[0035] This allows the electric heating element to be removed from the casing through an inspection opening when the emissions reduction module is removed. That is, the electric heating element may be attached to the DPF and / or DOC. In embodiments where the emissions reduction module is a combined DPF / DOC, the electric heating element is typically attached to the DOC. In embodiments where the electric heating element is attached to the emissions reduction module, the electric heating element is preferably attached to a second end portion of the emissions reduction module.

[0036] According to at least one exemplary embodiment, the emissions reduction module and the electric heating element are mounted on an inspection cover and are detachably positioned relative to the casing together with the inspection cover. This allows the electric heating element to be removed from the casing through an inspection opening when the inspection cover is removed.

[0037] According to at least one exemplary embodiment, the exhaust aftertreatment unit further comprises a secondary catalyst positioned between an emission reduction module and an electric heating element.

[0038] This allows the electric heating element to heat the secondary catalyst. Therefore, the electric heating element may be positioned upstream of the emissions reduction module and / or the secondary catalyst to improve the performance of the emissions reduction module and / or the secondary catalyst. The secondary catalyst is preferably positioned within a mounting socket. According to at least one exemplary embodiment, the secondary catalyst may be positioned to be removable from the casing and to be removable through an inspection opening in the casing when the inspection cover is removed, typically when the emissions reduction module is removed. This allows the inspection cover to share its function with the electric heating element, the emissions reduction module, and the secondary catalyst. According to at least one exemplary embodiment, the secondary catalyst is a secondary SCR catalyst.

[0039] According to at least one exemplary embodiment, the electric heating element is used in conjunction with the upstream injection of hydrocarbons, for example, fuel. That is, the upstream injection of such hydrocarbons is carried out upstream of the electric heating element. This can further enhance the heat dissipation of the electric heating element and / or DOC.

[0040] According to at least one exemplary embodiment, the inspection cover is removably positioned in the casing by a removable fastener, such as a clamp.

[0041] According to at least one exemplary embodiment, the exhaust aftertreatment unit further comprises an injector configured to inject a reducing agent to supply ammonia to an SCR catalyst, the injector being located upstream of the SCR catalyst and downstream of the emissions reduction module.

[0042] This allows the electric heating element to heat the exhaust gas passing through the electric heating element and the emission reduction module, and the heated exhaust gas then heats the injected reducing agent. As a result, the reducing agent produces ammonia by hydrolysis. Therefore, the electric heating element is positioned upstream of the injector. Thus, during use, the electric heating element heats the exhaust gas before it reaches the location of the injected reducing agent, and the heat transferred from the electric heating element to the exhaust gas heats the injected reducing agent. This reduces or eliminates the fouling caused by the injected reducing agent.

[0043] According to at least one exemplary embodiment in which the secondary catalyst is a secondary SCR catalyst, the exhaust aftertreatment unit further comprises a secondary injector configured to inject a reducing agent to supply ammonia to the secondary SCR catalyst, the secondary injector being located upstream of the secondary SCR catalyst. Optionally, the secondary injector is located upstream of the exhaust aftertreatment unit.

[0044] According to at least one exemplary embodiment, the reducing agent is at least one of anhydrous ammonia, aqueous ammonia, urea, aqueous urea, and diesel exhaust liquid. According to at least one exemplary embodiment, the reducing agent is urea or aqueous urea, hereinafter generally referred to as urea. Thus, the electric heating element supplies the necessary heat to the urea via the heated exhaust gas, thereby causing the urea to evaporate and produce ammonia by hydrolysis. Depending on the operating power of the electric heating element, the heated exhaust gas may further heat the SCR catalyst.

[0045] According to at least one exemplary embodiment, the SCR catalyst is located downstream of the emissions reduction module. The SCR catalyst converts nitrogen oxides (NOx) into diatomic nitrogen (N), water, and / or carbon dioxide (CO2) through catalytic action. During use, an injected reducing agent (or ammonia produced thereby) reacts with the catalyst.

[0046] According to at least one exemplary embodiment, the exhaust aftertreatment unit includes a control device configured to control various exhaust gas parameters for controlling the NOx concentration in the exhaust gas, such as the introduction of a reducing agent injected into the exhaust gas flow path as a function of NOx temperature and pressure. The exhaust gas parameters may be measured by various sensors at various locations within the exhaust aftertreatment unit. For example, NOx sensors may be located at or near the inlet and outlet of the exhaust aftertreatment unit. Temperature sensors and / or pressure sensors may be located before and after the electric heating element or SCR catalyst.

[0047] It should be understood that an electric heating element is a heating element configured to be heated by electricity. According to at least one exemplary embodiment, the electric heating element comprises a coil or plate configured to be heated by electricity passing through the coil or plate. The electric heating element may be arranged so that during use, exhaust gas is heated by passing circumferentially through the coil or across the coil or plate. The electric heating element may be in other shapes, for example, in the form of a flat or curved heating plate, or may consist of a different form, for example, a heating element of resistance foam. According to at least one exemplary embodiment, the electric heating element is an element based on a positive temperature coefficient PTC. According to at least one exemplary embodiment, the electric heating element may be called an induction heating element based on induction heating.

[0048] Therefore, during use, the exhaust gas flows through the exhaust aftertreatment unit and is guided to pass through an electric heating element, thereby heating the exhaust gas. The electric heating element typically comprises a heating surface positioned within the flow path of the exhaust aftertreatment unit, and during use, the exhaust gas in the flow path flows over or across this heating surface.

[0049] According to at least one exemplary embodiment, the operating power of the electric heating element is between 300W and 15000W or between 1000W and 15000W. According to at least one exemplary embodiment, the operating voltage of the electric heating element is 12V, 24V, or 48V.

[0050] For example, the electric heating element is configured to maintain the temperature of the exhaust gas flowing through the downstream channel between 180°C and 300°C. Additionally or alternatively, the electric heating element is configured to maintain the temperature within the SCR catalyst between 180°C and 300°C.

[0051] According to at least one exemplary embodiment, the electric heating element is controlled to begin heating the exhaust gas depending on whether the measured temperature upstream or downstream of the electric heating element (e.g., upstream or downstream of the emissions reduction module and / or any secondary catalyst) is below 180°C. According to at least one exemplary embodiment, the electric heating element is controlled to begin heating the exhaust gas depending on whether the measured temperature of the emissions reduction module and / or any secondary catalyst is below 200°C or below 180°C.

[0052] A second aspect of the present invention provides a method for handling a vehicle exhaust aftertreatment unit. The exhaust aftertreatment unit comprises an emissions reduction module which is a DPF and / or DOC; a selective catalytic reduction SRC catalyst; an electric heating element located upstream of the emissions reduction module; a casing housing at least the emissions reduction module and the electric heating element; and an inspection cover which is removablely arranged to cover an inspection opening in the casing, and through the inspection opening, the emissions reduction module is accessible. This method provides a method for handling a vehicle exhaust aftertreatment unit. -Steps to remove the inspection cover, - The step of removing the emission reduction module in order to access the electric heating element, - Steps to remove the electric heating element from the casing and Includes.

[0053] This allows for easy access to the electric heating element, enabling its removal from the casing for maintenance and / or replacement. According to at least one exemplary embodiment, the method includes the step of performing maintenance or replacement of the electric heating element. Thus, the method may also be referred to as a method for inspecting an exhaust aftertreatment unit. The electric heating element is positioned to be removable from the casing and accessible through an inspection opening when an inspection cover is removed. As described with reference to a first aspect of the present invention, the casing may be positioned to house the electric heating element and the emissions reduction module within a mounting socket. Thus, the step of removing the emissions reduction module to access the electric heating element may include removing the emissions reduction module from the casing by removing the emissions reduction module from the mounting socket. Similarly, the step of removing the electric heating element from the casing may include removing the electric heating element from the mounting socket. It should be understood that the term “remove from casing” means, for example, removing a component from its position inside the casing to its position outside the casing by separating the component from its mounting socket.

[0054] According to at least one exemplary embodiment, the exhaust aftertreatment unit to which the method of the second aspect of the present invention applies is the same as the exhaust aftertreatment unit described in the first aspect of the present invention. Accordingly, the effects and features of the exhaust aftertreatment unit in the second aspect of the present invention are substantially the same as those described above in relation to the first aspect of the present invention. Embodiments described in relation to the first aspect of the present invention are generally interchangeable with the exhaust aftertreatment unit in the second aspect of the present invention.

[0055] According to at least one exemplary embodiment, the electric heating element is removed from the casing by passing it through an inspection opening.

[0056] According to at least one exemplary embodiment, the electric heating element is attached to an emissions reduction module, and the steps of removing the emissions reduction module and removing the electric heating element are performed simultaneously.

[0057] This provides a simple and effective method for removing the electric heating element from the casing. Thus, the emissions reduction module is detachably positioned relative to the casing together with the electric heating element, and the electric heating element can be removed from the casing when the emissions reduction module is removed.

[0058] According to at least one exemplary embodiment, the emissions reduction module and the electric heating element are mounted on an inspection cover, and the steps of removing the inspection cover and removing the emissions reduction module and the electric heating element are performed simultaneously.

[0059] This provides a simple and effective method for removing the electric heating element from the casing. Thus, the inspection cover is detachably positioned relative to the casing together with the electric heating element (and emission reduction module), and the electric heating element can be removed from the casing when the inspection cover is removed.

[0060] According to at least one exemplary embodiment, the exhaust aftertreatment unit further comprises a secondary catalyst positioned between an emission reduction module and an electric heating element, and the electric heating element is attached to the secondary catalyst, the method is as follows: - The step of removing the electric heating element and the step of removing the secondary catalyst from the casing simultaneously. It also includes.

[0061] This provides a simple and effective method for removing the electric heating element from the casing. Thus, the secondary catalyst is detachably positioned relative to the casing together with the electric heating element, and the electric heating element can be removed from the casing when the secondary catalyst is removed. That is, the secondary catalyst is positioned to be detachable through the inspection opening of the casing when the inspection cover and emission reduction module are removed. Thus, maintenance or replacement of the secondary catalyst can be performed. Embodiments of the secondary catalyst have been described with reference to the first aspect of the present invention and will not be repeated here.

[0062] According to at least one exemplary embodiment, the electric heating element is configured to be powered via at least one electrical connection, as described with reference to the first aspect of the present invention. Thus, the electrical connection extends from the outer surface of the casing into an upstream mounting socket for the electric heating element. Furthermore, the exhaust aftertreatment unit may further include at least one guide element for guiding the electrical connection through the outer surface of the casing, wherein the electric heating element and at least one electrical connection are detachably mounted to the guide element, or the electric heating element, at least one electrical connection, and the guide element are detachably mounted to the outer surface of the casing.

[0063] Therefore, the method may include a step of separating the electric heating element from the casing (or mounting socket) by removing the electric heating element and at least one electrical connection from the guide element. This separates the electrical connection from the guide element, and then allows the electric heating element and electrical connection to be removed from the casing (and mounting socket). Alternatively, the method may include a step of separating the electric heating element from the casing (or mounting socket) by removing the electric heating element, at least one electrical connection, and the guide element from the outer surface of the casing. This separates the electrical connection and the guide element from the outer surface of the casing, and then allows the electric heating element, electrical connection, and guide element to be removed from the casing (and mounting socket).

[0064] Therefore, this method may include a step of separating or detaching the electrical connection from the guide element, or separating or detaching the guide element from the outer surface of the casing.

[0065] According to at least one exemplary embodiment, the method is - The step of attaching the electric heating element to the casing, - Steps to attach the inspection cover to the casing and It also includes.

[0066] This allows the inspected or serviced electric heating element to be removably reattached to the casing, or a new electric heating element to replace an old one to be removably attached to the casing. The step of attaching the electric heating element to the casing may include inserting the electric heating element into the casing by moving it through the inspection opening and, if possible, into the mounting socket. Thus, the inspection cover is attached to the casing after the step of attaching the electric heating element to the casing (or simultaneously with the step of attaching the electric heating element to the casing if the electric heating element is attached to the inspection cover). Typically, the inspection cover is attached to the casing by covering the inspection opening.

[0067] According to a third aspect of the present invention, an electric heating element used in an exhaust aftertreatment unit according to the first aspect of the present invention is provided.

[0068] The effects and features of the third aspect of the present invention are largely the same as those described above in relation to the first aspect of the present invention. Embodiments described in relation to the first aspect of the present invention are generally interchangeable with those of the third aspect of the present invention.

[0069] Accordingly, the exhaust aftertreatment unit comprises an emissions reduction module which is a DPF and / or DOC; a selective catalytic reduction (SCR) catalyst; an electric heating element positioned upstream of the emissions reduction module; a casing housing at least the emissions reduction module and the electric heating element; and an inspection cover removablely positioned in an inspection opening of the casing, the inspection cover allowing access to the emissions reduction module through the inspection opening. The electric heating element is removablely mountable to the exhaust aftertreatment unit, for example, by allowing access through the inspection opening, and is preferably removablely positioned inside the casing, preferably in a mounting socket. Typically, the electric heating element is shaped and sized to be positioned upstream of the emissions reduction module, preferably in a mounting socket.

[0070] A fourth aspect of the present invention provides the use of an electric heating element in an exhaust aftertreatment unit according to the first aspect of the present invention.

[0071] The effects and features of the fourth aspect of the present invention are largely the same as those described above in relation to the first, second, and third aspects of the present invention. The embodiments described in relation to the first, second, and third aspects of the present invention are generally interchangeable with the fourth aspect of the present invention.

[0072] According to a fifth aspect of the present invention, a vehicle is provided that is equipped with an exhaust aftertreatment unit according to a first aspect of the present invention.

[0073] The effects and features of the fifth aspect of the present invention are largely the same as those described above in relation to the first aspect of the present invention. Embodiments described in relation to the first aspect of the present invention are generally interchangeable with the fifth aspect of the present invention.

[0074] The order of the method steps described in the second aspect of the present invention is not limited to the order described herein. Unless otherwise specified, one or more of the steps may be performed in a different order or in a different order without departing from the scope of the invention. However, according to at least one exemplary embodiment, the method steps are performed in the order described in the second aspect of the present invention.

[0075] Further advantages and features of this disclosure are disclosed and discussed in the following description and accompanying drawings.

[0076] Exemplary embodiments of the present invention will be described in further detail below with reference to the attached drawings. [Brief explanation of the drawing]

[0077] [Figure 1] This is a schematic side view of a vehicle equipped with an exhaust aftertreatment unit according to an exemplary embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view of an exhaust aftertreatment unit according to an exemplary embodiment of the present invention. [Figure 3] This figure schematically illustrates an example of removing an electric heating element from a casing, which is applicable to exemplary embodiments of the present invention. [Figure 4A] This figure schematically illustrates an example of attaching an electrically heated element, applicable to exemplary embodiments of the present invention, to a casing via an electrical connection, and removing the electrically heated element from the casing. [Figure 4B] This figure schematically illustrates an example of attaching an electrically heated element, applicable to exemplary embodiments of the present invention, to a casing via an electrical connection, and removing the electrically heated element from the casing. [Figure 5A] This is a schematic cross-sectional view of a different exemplary embodiment of the exhaust aftertreatment unit of the present invention. [Figure 5B] This is a schematic cross-sectional view of a different exemplary embodiment of the exhaust aftertreatment unit of the present invention. [Figure 6] This flowchart shows the steps of a method according to one exemplary embodiment of the present invention. [Modes for carrying out the invention]

[0078] Referring to Figure 1, a vehicle 1 is shown which is embodied as a heavy-duty truck 1 to which the type of exhaust aftertreatment unit 20 described herein is advantageously applied. However, the exhaust aftertreatment unit 20 may be incorporated into other types of vehicles, such as buses, light trucks, passenger cars, marine applications, etc. The vehicle 1 in Figure 1 is equipped with an engine 10, specifically a diesel engine 10, but the vehicle may be a hybrid vehicle further comprising an electromechanical unit (not shown) according to at least one exemplary embodiment. The diesel engine 10 is typically powered by diesel fuel contained in a fuel tank, and any electromechanical unit is typically powered by electricity supplied from at least one energy storage or energy conversion device, such as a battery or fuel cell.

[0079] In Figure 1, vehicle 1 is equipped with an exhaust aftertreatment unit 20 for purifying exhaust gas from at least the diesel engine 10. The exhaust aftertreatment unit 20 comprises at least an emissions reduction module 30 which is a DPF and / or DOC, and a selective catalytic reduction catalyst 32 (hereinafter referred to as SCR catalyst 32) located downstream of the emissions reduction module 30. The emissions reduction module 30 is configured to remove particulate matter, i.e., diesel particulate matter or soot, from the exhaust gas of the diesel engine 10, and / or to convert carbon monoxide and hydrocarbons into carbon dioxide. The SCR catalyst 32 is configured to convert nitrogen oxides, also known as NOx, into diatomic nitrogen N2, water, and / or carbon dioxide CO2 through the action of the catalyst. A reducing agent, typically anhydrous ammonia, aqueous ammonia, urea, aqueous urea, or diesel exhaust fluid, is added to the engine exhaust gas and absorbed by the catalyst in the SCR catalyst 32. The exhaust aftertreatment unit 20 may be included within the vehicle's exhaust aftertreatment system, which may further include components such as piping and other emission reduction components.

[0080] In Figure 2, the exhaust aftertreatment unit 20 of Figure 1 is shown in more detail. The exhaust aftertreatment unit 20 comprises an inlet 22 for receiving exhaust gas, an outlet 24 for discharging at least partially purified exhaust gas from the exhaust aftertreatment unit 20, and a flow path 26 for transferring the exhaust gas from the inlet 22 to the outlet 24. The exhaust aftertreatment unit 20 further comprises an emissions reduction module 30 comprising a DPF (diesel particulate filter) 30A and a DOC (diesel oxidation catalyst) 30B, and an SCR catalyst 32 located downstream of the emissions reduction module 30. In Figure 2, the DPF 30A and DOC 30B are units separated from each other by a gap 30C. However, the DPF 30A may be located in the same unit as the DOC 30B, and / or may be firmly attached to each other by a connecting element bridging the gap 30C. Furthermore, in order to supply ammonia to the SCR catalyst 32, the exhaust aftertreatment unit 20 comprises an injector 34 for injecting a reducing agent, as described above. The reducing agent may be, for example, urea. The exhaust aftertreatment unit 20 further comprises a secondary catalyst 35 located upstream of the exhaust reduction module 30. In Figure 2, the secondary catalyst 35 is attached to the DOC 30B. The secondary catalyst 35 may be, for example, a secondary SCR. Furthermore, an electric heating element 38 is located upstream of the exhaust reduction module 30 and, in Figure 2, upstream of the secondary catalyst 35. Thus, the secondary catalyst 35 is located between the exhaust reduction module 30 and the electric heating element 38. The exhaust reduction module 30, the SCR catalyst 32, the secondary catalyst 35, and the electric heating element 38 are housed in a casing 40.

[0081] The exhaust aftertreatment unit 20 is typically operated as follows: Exhaust gas (to be purified) from the diesel engine enters the exhaust aftertreatment unit 20 via the inlet 22 and is heated through the electric heating element 38. The exhaust gas then passes through the secondary catalyst 35 and then through the emission reduction module 30 in the order of DOC 30B, gap 30C, and DPF 30A. Thus, the fact that the exhaust gas is heated improves the performance of the emission reduction module 30 and the secondary catalyst 35 before the exhaust gas flows continuously along the flow path 26 to the point where urea is injected by the injector 34. The injected reducing agent is then mixed with the heated exhaust gas, and it is desirable that the heat supplied by the electric heating element 38 is sufficient to evaporate the urea and produce ammonia by hydrolysis. The ammonia and exhaust gas then enter the SCR catalyst 32 for catalytic reduction of NOx, and the purified exhaust gas is then discharged from the exhaust aftertreatment unit 20 via the outlet 24.

[0082] In Figure 2, the casing 40 includes a mounting socket 41 that houses at least some components of the exhaust aftertreatment unit 20, namely the emission reduction module 30, the secondary catalyst 35, and the electric heating element 38. This allows the components 30, 35, and 38 to be satisfactorily arranged inside the casing 40. The mounting socket 41 is shaped tubular or cylindrical in Figure 2 and extends along its long axis L. Furthermore, the electric heating element 38 is powered by at least one electrical connection C that extends from the outer surface 43 of the casing 40 into the mounting socket 41 upstream of the electric heating element 38. The electrical connection C comprises two electrical connection lines, namely a power line (or phase line indicated by [+]) and a neutral line (indicated by [-]), but will hereafter be simply referred to as the electrical connection C. The electrical connection C extends into the mounting socket in a direction along the long axis L or in a direction parallel to the long axis L, as will be further discussed below. In Figure 2, the electrical connection C penetrates the casing 40 and the outer surface 43 via guide elements 45 (typically, one guide element is provided for each electrical connection wire, as shown in Figure 3). Thus, the guide elements 45 guide the electrical connection C through the casing 40 and the outer surface 43.

[0083] For various reasons, it is desirable that the emissions reduction module 30, the secondary catalyst 35, and / or the electric heating element 38 be accessible. Therefore, the casing 40 is provided with an inspection opening 42 through which at least the emissions reduction module 30 can pass (when removed from the casing 40). This allows the emissions reduction module 30 to be removed from the casing 40 for maintenance or replacement, and / or inserted into the casing 40 for installation. The inspection opening 42 can be closed by a removable inspection cover 44. In other words, the inspection cover 44 is removablely positioned to cover the inspection opening 42. Therefore, the inspection cover 44 is considered a separate component from the casing 40.

[0084] The electric heating element 38 is detachably positioned relative to the casing 40 by being detachably positioned relative to the mounting socket 41, for example, by being separable from the mounting socket 41 and / or the casing 40. Similarly, the emissions reduction module 30 (i.e., DPF 30A and DOC 30B in the example of Figure 2) is detachably positioned relative to the casing 40 by being detachably positioned relative to the mounting socket 41, for example, by being separable from the mounting socket 41 and / or the casing 40. Furthermore, typically, the secondary catalyst 35 is detachably positioned relative to the casing 40 by being detachably positioned relative to the mounting socket 41, for example, by being separable from the mounting socket 41 and / or the casing 40. Thus, the electric heating element 38 is positioned inside the casing 40 and inside the mounting socket 41, so as to be accessible through the inspection opening 42 when removing the inspection cover 44, the emissions reduction module 30, and the secondary catalyst 35. This allows the electric heating element 38 to be removed from the casing 40 and mounting socket 41 for replacement and / or maintenance.

[0085] The procedure for handling the exhaust aftertreatment unit 20 shown in Figure 2 will be briefly described below with reference to Figure 3. This method is sometimes referred to as the method for accessing the electrically heated element 38 in the casing 40 and / or mounting socket 41. First, the inspection cover 44 is removed from the casing 40, as shown in Figure 3. Next, the emissions reduction module 30 is removed from the casing 40 and mounting socket 41 by first removing the DPF 30A and then the DOC 30B. In the embodiment of Figure 3, since the DOC 30B is attached to the secondary catalyst 35, the secondary catalyst 35 is removed from the casing 40 and mounting socket 41 together with the emissions reduction module 30 and the DOC 30B. This allows access to the emissions reduction module 30 and the secondary catalyst 35 for maintenance or replacement, for example. However, it should be noted that the secondary catalyst 35 is optional and may be omitted from the exhaust aftertreatment unit 20. Furthermore, either the DOC 30B or the DPF 30A may be omitted from the exhaust aftertreatment unit 20. Therefore, the exhaust aftertreatment module 30 may simply be a DPF or a DOC.

[0086] Once the emissions reduction module 30 and the secondary catalyst 35 are removed from the casing, the electric heating element 38 can be accessed through the inspection opening 42. In the embodiment shown in Figure 3, the electric heating element 30 is attached to the electrical connection C and is therefore removably positioned relative to the casing 40 together with the electrical connection C. More specifically, the guide element 45 comprises a first guide element 45A for guiding one of the two electrical connection wires and a second guide element 45B for guiding the other of the two electrical connection wires. The electric heating element 38 and the electrical connection C having the two electrical connection wires are removably attached to the first and second guide elements 45A and 45B. Therefore, following the removal of the emissions reduction module 30 and the secondary catalyst 35, the electric heating element 38 can be removed from the casing 40 and mounting socket 41 through the inspection opening 42 by separating the electrical connection C from the guide elements 45A and 45B. This allows access to the electric heating element 38 for maintenance or replacement, for example. As shown in Figure 3, since the electrical connection C extends inward into the mounting socket 41 in a direction along the long axis L or parallel to the long axis L (or rather, since the first and second electrical connection wires extend in a direction along the long axis L or parallel to the long axis L), the electric heating element 38 can be removed axially by passing it outward through the casing 40 and mounting socket 41 in a direction along the long axis L or parallel to the long axis L, so that the electrical connection C can pass through the first and second guide elements 45A and 45B. Therefore, interference between the electrical connection C and the inner surface of the mounting socket 41 during removal of the electric heating element 38, which may cause it to become immobile, is avoided.

[0087] In another embodiment shown in Figures 4A and 4B, the electric heating element 38', at least one electrical connection C, and guide element 45' are removably mounted to the outer surface 43 of the casing. Here, the guide element 45' comprises at least one flange 46' that is securely attached to the electrical connection C of the electric heating element 38'. Furthermore, the flange 46' is configured to be attached to the mounting portion 43' of the outer surface 43 by screws 60. Thus, the flange 46' has multiple screw holes and is removably mounted to the mounting portion 43' of the outer surface 43 by screwing screws into the screw holes. This allows the electric heating element 38 to be removed from the casing and outer surface 43 together with the guide element 45' and electrical connection C by unscrewing and detaching the flange 46' from the mounting portion 43', as shown in Figure 4B. Therefore, as explained with reference to Figure 3, the electric heating element 38' can be removed axially by passing it outward through the casing 40 and mounting socket 41 in a direction along the long axis L or in a direction parallel to the long axis L.

[0088] Figure 5A shows an exhaust aftertreatment unit 120 according to an alternative embodiment. The exhaust aftertreatment unit 120 is very similar to the exhaust aftertreatment unit 20 in Figures 2-3, and the same reference numerals are used to refer to the same or corresponding components. Below, only the differences between these embodiments will be described in detail (only the differing parts of the exhaust aftertreatment unit 120 are shown in Figure 5A). In the embodiment of Figure 5A, the exhaust aftertreatment unit 120 comprises an emissions reduction module 130 and a secondary catalyst 135. The emissions reduction module 130 is a DPF and / or DOC and is separated from the secondary catalyst 135 inside the mounting socket 41 of the casing 40. Furthermore, in Figure 5A, an electric heating element 138 is mounted or incorporated within the secondary catalyst 135. This allows the electric heating element 138 to be removed together with the secondary catalyst 135 from the casing 40 and mounting socket 41. Therefore, the secondary catalyst 135, the electric heating element 138, and the electrical connection part C can be separated from the first and second guide elements 45A and 45B, and these components can be removed axially by passing them outward through the casing 40 and mounting socket 41 in a direction along the long axis L or in a direction parallel to the long axis L.

[0089] Figure 5B shows another embodiment of the exhaust aftertreatment unit 220. The exhaust aftertreatment unit 220 is very similar to the exhaust aftertreatment unit 20 in Figure 2-3, and the same reference numerals are used to refer to the same or corresponding components. Below, only the differences between these embodiments will be described in detail (only the differing parts of the exhaust aftertreatment unit 220 are shown in Figure 5B). In the embodiment of Figure 5B, the exhaust aftertreatment unit 120 includes an emissions reduction module 230 (the secondary catalyst is not located upstream of the emissions reduction module 230 within the mounting socket 41). The emissions reduction module 230 is a DPF and / or DOC and is located inside the mounting socket 41 of the casing 40. Furthermore, in Figure 5B, an electric heating element 238 is attached to the emissions reduction module 230. This allows the electric heating element 238 to be removed together with the emissions reduction module 230 from the casing 40 and mounting socket 41. Therefore, the emissions reduction module 230, the electric heating element 238, and the electrical connection part C can be separated from the first and second guide elements 45A and 45B, and these components can be removed axially by passing them outward through the casing 40 and mounting socket 41 in a direction along the long axis L or in a direction parallel to the long axis L.

[0090] It should be noted that the secondary catalysts 35, 135 and the emission reduction modules 30, 130, 230 are structurally and functionally distinct from each other, as are the guide elements 45, 45A, 45B, 45'. Therefore, the exhaust aftertreatment units 20, 120, 220 may or may not include the secondary catalysts 35, 135, and / or the guide elements 45, 45A, 45B, 45'. Furthermore, the DPF 30A and DOC 30B are structurally and functionally distinct from each other and may be combined as DPF 30A / DOC 30B within the emission reduction modules 130, 230 in Figures 5A-5B, or one may be included within the emission reduction module 30 in Figure 2 without the other.

[0091] Referring to the flowchart in Figure 6, the steps of a method for handling or inspecting a vehicle exhaust aftertreatment unit are schematically shown. Exhaust aftertreatment units include, for example, the exhaust aftertreatment unit 20 in Figures 2-3 (which may have the configuration of the electric heating element 38' in Figures 4A-4B), the exhaust aftertreatment unit 120 in Figure 5A, and the exhaust aftertreatment unit 220 in Figure 5B. Thus, the exhaust aftertreatment unit comprises an emissions reduction module which is a DPF and / or DOC, a selective catalytic reduction SCR catalyst, an electric heating element located upstream of the emissions reduction module, a casing housing at least the emissions reduction module and the electric heating element, and an inspection cover which is removablely positioned to cover an inspection opening in the casing, allowing access to the emissions reduction module through the inspection opening.

[0092] In step S1, the inspection cover is removed. This allows access to at least the emissions reduction module for maintenance and / or replacement.

[0093] In step S2, the emissions reduction module is removed to access the electric heating element. The emissions reduction module is removed from the casing, thereby allowing for maintenance or replacement.

[0094] In step S4, the electric heating element is removed from the casing. This allows for maintenance or replacement of the electric heating element.

[0095] Typically, since the electric heating element and the emissions reduction module are located within a mounting socket, step S2 for removing the emissions reduction module includes removing the emissions reduction module from the mounting socket, and step S4 for removing the electric heating element includes removing the electric heating element from the mounting socket.

[0096] Furthermore, as described with reference to the exhaust aftertreatment units 20,120 in Figure 2,5A, the exhaust aftertreatment unit may include a secondary catalyst positioned between the emission reduction module and the electric heating element. Thus, in the optional step S3, the secondary catalyst is removed from the casing.

[0097] In one exemplary embodiment, the electric heating element may be attached to the emissions reduction module. Thus, the steps of removing the emissions reduction module (S2) and removing the electric heating element (S4) may be performed simultaneously. Additionally or alternatively, the electric heating element may be attached to the secondary catalyst. In this case, the steps of removing the secondary catalyst from the casing (S3) and removing the electric heating element (S4) may be performed simultaneously. According to at least one exemplary embodiment, the electric heating element is attached to the emissions reduction module and the secondary catalyst, and the steps of removing the emissions reduction module (S2), removing the electric heating element (S4), and removing the secondary catalyst (S3) are performed simultaneously.

[0098] Therefore, step S1 may be a first procedure S1, for example, as shown in Figure 3 (where the inspection cover is removed before step S2, which removes the emissions reduction module), and therefore step S2 may be a second procedure S2. Alternatively, steps S1 and S2 may be performed simultaneously, in which case the inspection cover is removed together with the emissions reduction module. Furthermore, step S3 may be a third procedure or a procedure after step 2. In this case, the secondary catalyst is removed from the casing after the second procedure S2 or after the combined steps S1 and S2. Furthermore, step S4 may be a fourth procedure or a procedure after step S2 or S3. In this case, the electric heating element is removed from the casing following the second procedure S2 or the third procedure S3. In a further alternative where the secondary catalyst is not located upstream of the emissions reduction module within the casing, the inspection cover is attached to the electric heating element via the emissions reduction module, and steps S1 (removing the inspection cover), S2 (removing the emissions reduction module), and S4 (removing the electric heating element) are performed simultaneously.

[0099] In the optional step S5, the electric heating element is either attached to the casing or reattached to the casing. Thus, such an optional step S5 is performed at least following step S4, which involves removing the electric heating element S4. For example, the electric heating element may be inserted into the casing and mounting socket.

[0100] In the optional step S6, the inspection cover is attached to the casing. If an electric heating element is attached to the inspection cover, for example via an emissions reduction module, the optional step S5 may be performed simultaneously with the optional step S6.

[0101] It should be understood that the present invention is not limited to the embodiments shown in the drawings. Rather, those skilled in the art will recognize that many changes and modifications can be made within the scope of the appended claims. For example, the exhaust aftertreatment unit may be used to purify the exhaust gas of engines other than diesel engines. For example, this exhaust aftertreatment unit may be used to purify the exhaust gas by converting NOx emissions from the exhaust of an internal combustion engine based on CNG (compressed natural gas), LPG (liquefied high-pressure gas), DME (dimethyl ether), and / or H2 (hydrogen).

[0102] In addition, the modifications of the disclosed embodiments will be understood and will influence those skilled in the art in embodying the concept of the invention as claimed from the drawings, disclosures, and appended claims. In the claims, the term “comprising” does not preclude other elements or steps, and the indefinite articles “a, an” do not preclude plurals. Although several means are described in different dependent claims, this is merely a fact and does not imply that no advantages can be obtained by using a combination of these means.

Claims

1. An exhaust aftertreatment unit (20, 120, 220) for purifying exhaust gas, comprising: - An emissions reduction module (30, 130, 230) that is a diesel particulate filter DPF (30A) and / or a diesel oxidation catalyst DOC (30B); - A selective catalytic reduction SCR catalyst (32); - An electric heating element (38, 38', 138, 238) disposed upstream of the emissions reduction module; - A casing (40) that houses at least the emissions reduction module and the electric heating element; - An inspection lid (44) removably disposed to cover an inspection opening (42) of the casing, the inspection lid (44) allowing access to the emissions reduction module through the inspection opening; characterized in that: The electric heating element is disposed on the side opposite to the inspection lid of the emissions reduction module, is removably disposed with respect to the casing, and is disposed so as to be accessible when the inspection lid and the emissions reduction module are removed. The exhaust aftertreatment unit (20, 120, 220).

2. The exhaust aftertreatment unit (20, 120, 220) according to claim 1, wherein the casing includes a mounting socket (41) that houses the emissions reduction module (30, 130, 230) and the electric heating element (38, 138, 238).

3. The exhaust aftertreatment unit (20, 120, 220) according to claim 2, wherein the electric heating element is powered by at least one electrical connection part (C) that extends from the outer surface (43) of the casing into the mounting socket upstream of the electric heating element.

4. The exhaust aftertreatment unit (20, 120, 220) according to claim 3, further comprising at least one guide element (45, 45A, 45B, 45') for guiding the electrical connection part through the outer surface of the casing, wherein the electric heating element (38, 138, 238) and the at least one electrical connection part (C) are removably attached to the guide element (45, 45A, 45B), or the electric heating element (38'), the at least one electrical connection part (C), and the guide element (45') are removably attached to the outer surface of the casing.

5. The mounting socket (41) extends along the major axis (L), and the at least one electrical connection part (C) extends inside the mounting socket in a direction along the major axis or a direction parallel to the major axis. The exhaust post-treatment unit (20, 120, 220) according to claim 3.

6. The exhaust emission reduction module and the electric heating element are removably arranged with respect to the mounting socket. The exhaust post-treatment unit (20, 120, 220) according to claim 2.

7. The electric heating element (238) is attached to the exhaust emission reduction module (230), and is removably arranged with respect to the casing (40) together with the exhaust emission reduction module. The exhaust post-treatment unit (220) according to claim 1.

8. The exhaust post-treatment unit ( ２０，２２０）。

9. The exhaust post-treatment unit (20) according to claim 1, further comprising an injector (34) configured to inject a reducing agent to supply ammonia to the SCR catalyst, wherein the injector is arranged upstream of the SCR catalyst and downstream of the exhaust emission reduction module.

10. A method for handling an exhaust post-treatment unit for a vehicle, the exhaust post-treatment unit comprising an exhaust emission reduction module which is a DPF and / or a DOC, a selective catalytic reduction SCR catalyst, an electric heating element arranged upstream of the exhaust emission reduction module, a casing for housing at least the exhaust emission reduction module and the electric heating element, and an inspection cover removably arranged to cover an inspection opening of the casing, the inspection cover allowing access to the exhaust emission reduction module through the inspection opening, and the electric heating element being arranged on the side of the exhaust emission reduction module opposite to the inspection cover. The method comprises: - a step (S1) of removing the inspection cover; - a step (S2) of removing the exhaust emission reduction module to access the electric heating element; - a step (S4) of removing the electric heating element from the casing; The method including.

11. The method according to claim 10, wherein the electric heating element is attached to the emission reduction module, and the step (S2) of removing the emission reduction module and the step (S4) of removing the electric heating element are performed simultaneously.

12. The exhaust aftertreatment unit further comprises a secondary catalyst disposed between the emission reduction module and the electric heating element, the electric heating element is attached to the secondary catalyst, and the method comprises: - a step (S3) of removing the secondary catalyst from the casing simultaneously with the step (S4) of removing the electric heating element The method according to claim 10, further comprising.

13. - a step (S5) of attaching the electric heating element to the casing; and - a step (S6) of attaching the inspection cover to the casing The method according to claim 10, further comprising.

14. A vehicle (1) comprising an exhaust aftertreatment unit (20, 120) according to any one of claims 1-9.

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