Post-processing system and vehicle

Abstract

The utility model relates to the technical field of vehicles, in particular to an after-treatment system and a vehicle, the after-treatment system comprises a front-stage SCR, a particle trap, a rear-stage mixer and a rear-stage SCR, and the front-stage SCR is used for being communicated with a waste gas discharge outlet of an engine; the first end of the particle trap is communicated with an outlet of the preceding-stage SCR, and the interior of the first end of the particle trap is coated with a DOC coating; an inlet of the post-stage mixer is communicated with an outlet of the particle trap; and the post-stage SCR is communicated with an outlet of the post-stage mixer. According to the utility model, the weight and the cost can be reduced while the tail gas emission reaches the standard.

Description

TECHNICAL FIELD

[0001] The utility model relates to vehicle technical field especially relates to a post-processing system and vehicle. BACKGROUND

[0002] Vehicle plays a very important role in daily life traffic and logistics transportation. With the increase of vehicle ownership, the influence of vehicle exhaust emission on the environment is more and more big. In order to treat the exhaust of vehicle, the post-processing system is usually installed at the exhaust emission port of engine, and the post-processing system converts the harmful substances discharged by engine into harmless or low pollution substances through the synergistic effect of multiple technologies. In the prior art, for gasoline vehicle and light-duty diesel vehicle, a catalytic converter (three-way catalytic converter) can be used to convert carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) into carbon dioxide (CO2), water (H2O) and nitrogen (N2) through oxidation-reduction reaction. For heavy-duty diesel vehicle, selective catalytic reduction (SCR) system is used in cooperation with diesel particulate filter (DPF), urea solution (such as AdBlue) is sprayed into exhaust gas, urea is decomposed into ammonia (NH3), and NOx is reduced to nitrogen (N2) and water (H2O) under the action of catalyst, and diesel particulate filter (DPF) traps carbon particles (PM) in diesel exhaust.

[0003] The post-processing system used on the vehicle usually adopts single-stage catalytic reducer cooperating with diesel oxidation catalyst (DOC) and diesel particulate filter, and the conversion capacity of nitrogen oxides (NOx) is low, which causes that the exhaust sometimes does not meet the standard. The double-stage catalytic reducer cooperates with diesel oxidation catalyst (DOC), diesel particulate filter and mixer, which is heavy in weight and increases the cost of post-processing system.

[0004] Therefore, a post-processing system and vehicle are needed to solve the above problems. UTILITY MODEL CONTENT

[0005] The utility model aims at providing a post-processing system and vehicle, which can ensure that the exhaust emission meets the standard, and reduce the weight and cost.

[0006] To achieve this purpose, the utility model adopts the following technical scheme:

[0007] The post-processing system comprises:

[0008] The front-stage SCR is used for communicating with the exhaust emission port of engine;

[0009] The diesel particulate filter is communicated with the outlet of the front-stage SCR, and the first end of the diesel particulate filter is coated with DOC coating inside;

[0010] a rear-stage mixer, an inlet of the rear-stage mixer being communicated with an outlet of the particle trap;

[0011] a rear-stage SCR, an outlet of the rear-stage mixer being communicated with an inlet of the rear-stage SCR.

[0012] In some embodiments, a content of Pt in the DOC coating: a content of Pd is greater than 12:1.

[0013] In some embodiments, a ratio of a length of the front-stage SCR along an axial direction to a length of the particle trap along an axial direction is greater than or equal to 1 and less than or equal to 2.

[0014] In some embodiments, the front-stage SCR, the particle trap, the rear-stage mixer and the rear-stage SCR are arranged in a U shape.

[0015] In some embodiments, the rear-stage mixer and the particle trap are connected by a first clamp.

[0016] In some embodiments, the rear-stage SCR and the rear-stage mixer are connected by a second clamp.

[0017] In some embodiments, a fixing assembly is further included, the fixing assembly being arranged between the front-stage SCR, the particle trap and the rear-stage SCR, and being used for locking relative positions between the front-stage SCR, the particle trap and the rear-stage SCR.

[0018] In some embodiments, the fixing assembly includes a connecting rod, and a first fixing member and a second fixing member arranged on the connecting rod, the first fixing member and the second fixing member being arranged at intervals, one end of the first fixing member being connected with the front-stage SCR, the other end of the first fixing member being connected with the rear-stage SCR, one end of the second fixing member being connected with the particle trap, and the other end of the second fixing member being connected with the rear-stage SCR.

[0019] In some embodiments, a support frame is further included, the support frame being arranged on an outer side of the front-stage SCR away from the rear-stage SCR.

[0020] A vehicle includes a chassis, an engine and an aftertreatment system as described above, the engine being arranged on the chassis, the aftertreatment system being arranged on the chassis, and an inlet of a front-stage SCR of the aftertreatment system being communicated with an exhaust port of the engine.

[0021] The vehicle has the following beneficial effects:

[0022] The utility model provides a kind of post-processing system, front SCR is used to communicate with the exhaust port of engine, the first end of particulate trap is communicated with the outlet of front SCR, and the first end inside particulate trap is coated with DOC coating layer.Back mixer is communicated with the outlet of particulate trap, and back SCR is communicated with the outlet of back mixer.By using the double-stage SCR arrangement of front SCR and back SCR, the conversion capacity of nitrogen oxide (NOx) is improved, NH3 escape and N2O generation can be accurately controlled, so that exhaust emission is more in line with the limit value requirement of greenhouse gas N2O in standard.Moreover, redundancy design can be realized, and the reliability of exhaust treatment is improved.If one-stage SCR fails or fails due to low temperature, the other stage SCR can still maintain basic denitration function, avoiding the risk of emission exceeding standard caused by complete dependence on single-stage SCR.By coating DOC coating layer on the first end of particulate trap, the function of diesel oxidation catalyst can be played, so that carbon monoxide (CO), hydrocarbons (HC) and particulate matter (PM) in exhaust gas are reduced by catalytic oxidation.Due to the integration of DOC coating layer in particulate trap, diesel oxidation catalyst is replaced, so that the weight and cost of post-processing system are reduced while ensuring exhaust treatment performance.

[0023] The utility model provides a kind of vehicle, including chassis, engine and as described above post-processing system, can guarantee exhaust emission standard while reducing weight and cost. ACCURACY OF DRAWINGS

[0024] In order to more clearly illustrate the technical scheme in the embodiments of the utility model, the drawings needed to be used in the description of the embodiments of the utility model will be simply introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained according to the contents of the embodiments of the utility model and these drawings without creative labor for those skilled in the art.

[0025] Figure 1 It is a schematic view of the post-processing system of the utility model.

[0026] In the drawing:

[0027] 1, front SCR; 11, support frame; 2, particulate trap; 3, back mixer; 4, back SCR; 5, first clamp; 6, second clamp; 7, fixed assembly; 71, connecting rod; 72, second fixing part; 73, first fixing part. DETAILED DESCRIPTION

[0028] Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the above-described drawings.

[0029] In this application, the terms "comprise", "contain", "include", or any other variant thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without more limitations, the element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0030] In this application, the terms "connect", "combine", "couple", "mount" can be direct connection, combination, coupling or mounting, or indirect connection, combination, coupling or mounting. For example, direct connection refers to the connection of two parts or components without the need to set intermediate parts, and indirect connection refers to the connection of two parts or components with at least one intermediate part, and the two parts or components are connected through the intermediate part. In addition, "connection" and "coupling" are not limited to physical or mechanical connection or coupling, and can include electrical connection or coupling.

[0031] In this application, those of ordinary skill in the art will understand that the functions performed by the components can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by the parts can also be performed by one part, one component, or multiple parts in combination.

[0032] In this application, the terms "up", "down", "left", "right", "front", "back", and the like are described in the orientation and positional relationship shown in the drawings, and should not be understood as limiting the embodiments of the application. In addition, it should be understood in the context that when referring to one element connected to another element "on" or "under", it can be directly connected to another element "on" or "under", or indirectly connected to another element "on" or "under" through an intermediate element. It should also be understood that the terms "up", "down", "left", "right", "front", "back", and the like not only represent the positive direction, but also can be understood as the side direction. For example, the lower side can include the lower side, the lower left side, the lower right side, the lower front side, and the lower back side, etc.

[0033] In the design and manufacture of the aftertreatment system of the vehicle, in order to ensure that the exhaust emission meets the standard while reducing the weight and cost, as shown in the figure, the utility model provides a kind of aftertreatment system. Figure 1 Aftertreatment system includes front SCR1, particulate trap 2, rear mixer 3 and rear SCR4.

[0034] The front-stage SCR 1 is used for communication with the exhaust port of the engine. The first end of the particulate filter 2 is in communication with the outlet of the front-stage SCR 1, and the inside of the first end of the particulate filter 2 is coated with a DOC coating. The inlet of the rear-stage mixer 3 is in communication with the outlet of the particulate filter 2. The rear-stage SCR 4 is in communication with the outlet of the rear-stage mixer 3.

[0035] By adopting the two-stage SCR arrangement of the front-stage SCR 1 and the rear-stage SCR 4, the conversion capacity of nitrogen oxides (NOx) is improved, the NH3 escape and N2O generation can be precisely controlled, and the tail gas emission can meet the limit value requirement of the standard for greenhouse gas N2O. Moreover, redundancy design can be achieved, and the reliability of tail gas treatment is improved. If one stage of SCR fails or fails at low temperature, the other stage of SCR can still maintain the basic denitration function, avoiding the risk of emission exceeding the standard caused by complete dependence on single-stage SCR. Moreover, the two-stage SCR can cover a wider temperature range and working condition through the division of labor of the front-stage SCR 1 and the rear-stage SCR 4. For example, the front-stage SCR 1 starts the reduction reaction at a lower temperature, and the rear-stage SCR 4 further optimizes the conversion efficiency at a high temperature section, and the overall NOx conversion rate is improved by about 20%-30% compared with a single-stage system. In the two-stage SCR architecture, the waste heat of the rear-stage SCR 4 can assist the passive regeneration of the particulate filter 2, reduce the frequency of active regeneration, and thus reduce fuel consumption and secondary emissions of particulate matter.

[0036] By coating the DOC coating on the first end of the particulate filter 2, the function of the diesel oxidation catalyst can be achieved, thereby reducing carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM) in the tail gas through catalytic oxidation. Since the DOC coating is integrated in the particulate filter 2, replacing the arrangement of the diesel oxidation catalyst, the weight and cost of the aftertreatment system are reduced while ensuring the tail gas treatment performance.

[0037] In some embodiments, the content of Pt: the content of Pd in the DOC coating is greater than 12:1. The DOC coating plays a very important role in the aftertreatment system, reducing carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM) in the tail gas through catalytic oxidation. Adopting platinum and palladium (Pt and Pd) double coating as the DOC coating can significantly optimize the catalytic activity. When the content of Pt: the content of Pd in the DOC coating is greater than 12:1, the oxidation capacity of the DOC coating can be further improved, so that the oxidation of NO generates NO2, promoting passive regeneration of soot. Moreover, through the above setting, there is no need to arrange an HC injection system, thereby further reducing the weight and cost of the aftertreatment system.

[0038] In some embodiments, the ratio of the length of the front SCR 1 along the axial direction to the length of the particulate filter 2 along the axial direction is greater than or equal to 1 and less than or equal to 2. By the above arrangement, the lengths of the front SCR 1 and the particulate filter 2 can be optimized, facilitating the arrangement and being conducive to the active regeneration of the particulate filter 2. In the present embodiment, the passive regeneration is generally selected as the regeneration mode of the particulate filter 2, while the power of the engine is raised by the injection of diesel, so as to improve the temperature of the DOC and realize the active regeneration of the particulate filter 2 as a safety measure. When the particulate filter 2 is actively regenerated, the temperature sensors arranged before and after the DOC coating are used for detection, and the diesel injection amount is controlled by the difference between the two temperature sensors. Specifically, the detection of the temperature to control the diesel injection amount in the engine belongs to the prior art, and the working principle thereof will not be described in detail herein.

[0039] In some embodiments, the front SCR 1, the particulate filter 2, the rear mixer 3 and the rear SCR 4 are arranged in a U shape. By optimizing the arrangement form among the front SCR 1, the particulate filter 2, the rear mixer 3 and the rear SCR 4, the compactness can be improved, the space occupation can be reduced, and the arrangement and installation on the vehicle chassis can be facilitated.

[0040] In some embodiments, the rear mixer 3 and the particulate filter 2 are connected by the first clamp 5. By using the first clamp 5 for connection, the butt joint installation between the rear mixer 3 and the particulate filter 2 can be quickly realized. When one of the rear mixer 3 and the particulate filter 2 fails, the quick disassembly and replacement can also be facilitated, so as to ensure the convenience of maintenance.

[0041] In some embodiments, the rear SCR 4 and the rear mixer 3 are connected by the second clamp 6. By using the second clamp 6 for connection, the butt joint installation between the rear SCR 4 and the rear mixer 3 can be quickly realized. When one of the rear SCR 4 and the rear mixer 3 fails, the quick disassembly and replacement can also be facilitated, so as to ensure the convenience of maintenance.

[0042] In some embodiments, the aftertreatment system further comprises a fixing assembly 7 arranged between the front SCR 1, the particulate filter 2 and the rear SCR 4, for locking the relative positions among the front SCR 1, the particulate filter 2 and the rear SCR 4. By arranging the fixing assembly 7, the stability of the connection of the aftertreatment system can be ensured.

[0043] In some embodiments, the fixing assembly 7 comprises a connecting rod 71, and a first fixing member 73 and a second fixing member 72 fixedly arranged on the connecting rod 71, the first fixing member 73 and the second fixing member 72 are arranged at intervals, one end of the first fixing member 73 is connected with the front SCR 1, the other end of the first fixing member 73 is connected with the rear SCR 4, one end of the second fixing member 72 is connected with the particulate filter 2, and the other end of the second fixing member 72 is connected with the rear SCR 4. Through the above arrangement, the aftertreatment system is formed as a whole by the fixing assembly 7, so as to ensure the strength of the aftertreatment system and ensure the structural stability of the aftertreatment system during the driving of the vehicle, and the aftertreatment system can work effectively. In the embodiment, two groups of the fixing assembly 7 are arranged, so as to further ensure the structural stability of the aftertreatment system.

[0044] In some embodiments, the aftertreatment system further comprises a support frame 11 fixedly arranged on the outer side of the front SCR 1 away from the rear SCR 4. By arranging the support frame 11, the subsequent aftertreatment system can be conveniently connected and installed with the chassis of the vehicle.

[0045] The embodiment further provides a vehicle, which comprises a chassis, an engine and the above aftertreatment system, the engine is arranged on the chassis, the aftertreatment system is arranged on the chassis, and the inlet of the front SCR 1 of the aftertreatment system is communicated with the exhaust port of the engine. By reasonably designing the aftertreatment system, the exhaust emission can be ensured to meet the standard, and the weight and cost can be reduced.

[0046] Obviously, the above embodiments of the utility model are only examples for clearly explaining the utility model, and are not the limitation on the embodiments of the utility model. For the ordinary skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the embodiments are not required to be exhausted. Any modification, equivalent replacement and improvement made in the spirit and principle of the utility model should be included in the protection scope of the utility model claim.

Claims

1. An aftertreatment system, characterized by, Comprising: a front-stage SCR (1) for communicating with an exhaust port of an engine; a particulate filter (2), a first end of the particulate filter (2) communicating with an outlet of the front-stage SCR (1), an inside of the first end of the particulate filter (2) being coated with a DOC coating; a rear-stage mixer (3), an inlet of the rear-stage mixer (3) communicating with an outlet of the particulate filter (2); a rear-stage SCR (4) communicating with an outlet of the rear-stage mixer (3).

2. The aftertreatment system of claim 1, wherein, A content of Pt in the DOC coating is greater than 12:1 of a content of Pd.

3. The aftertreatment system of claim 1, wherein, A ratio of an axial length of the front-stage SCR (1) to an axial length of the particulate filter (2) is greater than or equal to 1 and less than or equal to 2.

4. The aftertreatment system of claim 1, wherein, The front-stage SCR (1), the particulate filter (2), the rear-stage mixer (3) and the rear-stage SCR (4) are arranged in a U shape.

5. The aftertreatment system of any of claims 1-4, wherein, The rear-stage mixer (3) and the particulate filter (2) are connected by a first clamp (5).

6. The aftertreatment system of any of claims 1-4, wherein, The rear-stage SCR (4) and the rear-stage mixer (3) are connected by a second clamp (6).

7. The aftertreatment system of claim 4, wherein, Further comprising a fixing assembly (7) disposed between the front-stage SCR (1), the particulate filter (2) and the rear-stage SCR (4) for locking relative positions between the front-stage SCR (1), the particulate filter (2) and the rear-stage SCR (4).

8. The aftertreatment system of claim 7, wherein, The fixing assembly (7) comprises a connecting rod (71) and a first fixing member (73) and a second fixing member (72) disposed on the connecting rod (71), the first fixing member (73) and the second fixing member (72) being spaced apart, one end of the first fixing member (73) being connected with the front-stage SCR (1), the other end of the first fixing member (73) being connected with the rear-stage SCR (4), one end of the second fixing member (72) being connected with the particulate filter (2), the other end of the second fixing member (72) being connected with the rear-stage SCR (4).

9. The aftertreatment system of claim 1, wherein, Further comprising a support frame (11) disposed on an outer side of the front-stage SCR (1) away from the rear-stage SCR (4).

10. Vehicle, characterized in that A chassis, an engine and an aftertreatment system as claimed in any one of claims 1-9, the engine being disposed on the chassis, the aftertreatment system being arranged on the chassis, and an inlet of a front-stage SCR (1) of the aftertreatment system communicating with an exhaust port of the engine.

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