Anti-crystallization device for urea of SCR (Selective Catalytic Reduction) system

Abstract

The utility model discloses an SCR (Selective Catalytic Reduction) system urea anti-crystallization device which comprises a multi-layer structure wrapped on an exhaust pipeline, the multi-layer structure comprises a heat conduction layer, a heating layer, a heat storage layer and a heat preservation layer from inside to outside, and the heat conduction layer is connected with the heat storage layer to ensure the temperature of the exhaust pipeline when an engine runs. Therefore, the influence of urea crystallization on the quality of the exhaust pipeline is effectively reduced.

Description

Technical Field

[0001] This utility model belongs to the field of automotive exhaust gas treatment technology, and more specifically relates to a urea anti-crystallization device for an SCR system. Background Technology

[0002] SCR systems are crucial in diesel vehicles. They typically use a urea solution to catalytically reduce nitrogen oxides in diesel engine exhaust into nitrogen and water, thus reducing diesel pollution. Specifically, urea is atomized and sprayed into the exhaust pipe to participate in the reaction. However, when the urea spray comes into direct contact with the high-temperature exhaust, especially during engine startup or prolonged idling, the exhaust temperature is low, leading to a low exhaust pipe temperature. This causes the atomized urea solution to evaporate slowly or not easily, resulting in it adhering to the inner wall of the exhaust pipe. After the water evaporates, crystals form. Excessive crystals can clog the exhaust pipe, increasing exhaust resistance, leading to decreased vehicle power and increased fuel consumption. Furthermore, high concentrations of urea can corrode metals, potentially damaging the exhaust pipe.

[0003] Devices to prevent urea crystallization are usually placed on the urea solution nozzle, as crystallization is more likely to occur at the nozzle, but there is a lack of preventative measures for the exhaust pipe. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a urea anti-crystallization device for an SCR system. This device is a multi-layered structure installed on the exhaust pipe to ensure the temperature of the exhaust pipe during engine operation and reduce urea crystallization.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a urea anti-crystallization device for an SCR system, comprising a multi-layer structure wrapped around an exhaust pipe, consisting of a heat-conducting layer, a heating layer, a heat storage layer, and a heat insulation layer from the inside out, wherein the heat-conducting layer and the heat storage layer are connected.

[0006] Furthermore, the heat-conducting layer includes a heat-conducting sleeve that is attached to the outer circumference of the exhaust pipe, and the heat-conducting sleeve is provided with a plurality of heat-conducting fins that extend into the heat storage layer.

[0007] Furthermore, the heating layer is a spiral electromagnetic coil sleeved on the outer circumference of the heat-conducting sleeve, and the plurality of heat-conducting fins form a continuous spiral shape, with the electromagnetic coil inserted inside the heat-conducting fins.

[0008] Furthermore, the outer circumference of the electromagnetic coil is wrapped with an insulating sleeve.

[0009] Furthermore, the gap between the heat-conducting sleeve and the exhaust pipe is filled with heat-conducting grease or heat-conducting adhesive, and the seal between the heat-conducting fins and the heat storage layer is filled with heat-conducting grease or heat-conducting adhesive.

[0010] Furthermore, the distance between two adjacent heat-conducting fins is less than the width of the heat-conducting fins.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: When the temperature inside the exhaust pipe is low, such as during the initial start-up of a diesel engine or when it is idling for a long time, the power supply of the electromagnetic coil can be turned on to heat the metal exhaust pipe, thereby effectively preventing urea crystallization. When the diesel engine is running normally, the temperature of the exhaust pipe is high. At this time, the heat is transferred to the heat storage layer through the heat-conducting layer and heat-conducting fins. The heat storage layer absorbs the heat, and when the diesel engine starts idling, the heat storage layer can transfer heat back to the exhaust pipe to maintain the temperature of the exhaust pipe and prevent urea crystallization. In this way, by setting a multi-layer structure outside the exhaust pipe, the temperature of the exhaust pipe during engine operation is guaranteed, thereby effectively reducing urea crystallization and affecting the quality of the exhaust pipe. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the urea anti-crystallization device in the SCR system of this utility model;

[0013] Figure 2 for Figure 1 Enlarged view of section A.

[0014] Reference numerals: 1. Exhaust pipe; 2. Heat-conducting layer; 3. Heating layer; 4. Heat storage layer; 5. Insulation layer; 6. Heat-conducting sleeve; 7. Heat-conducting fins; 8. Electromagnetic coil; 9. Insulation sleeve. Detailed Implementation

[0015] In the description of this utility model, it should be noted that the directional terms such as "center", "horizontal (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this utility model.

[0016] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature. In the description of this utility model, "several" or "a number" means two or more, unless otherwise explicitly specified.

[0017] Reference Figure 1 and Figure 2 The present invention will be further described below.

[0018] A urea anti-crystallization device for an SCR system includes a multi-layer structure wrapped around an exhaust pipe 1, comprising a heat-conducting layer 2, a heating layer 3, a heat storage layer 4, and a heat insulation layer 5 from the inside out, wherein the heat-conducting layer 2 is connected to the heat storage layer 4.

[0019] Specifically, the insulation layer 5 can prevent the heat from being lost from the heat storage layer 4.

[0020] Specifically, a drive mechanism can be connected to the insulation layer 5. When the temperature of the exhaust pipe 1 is too high, the insulation layer 5 can be opened through the drive mechanism to expose the heat storage layer 4 and realize the heat dissipation of the exhaust pipe 1.

[0021] Specifically, the insulation layer can be divided into two semi-cylindrical tubes, and a telescopic device, such as an electric telescopic rod, can be connected to the two semi-cylindrical tubes. For trucks or vans with specific pneumatic systems, cylinders can be used.

[0022] Specifically, the multi-layer structure can be set near the urea solution injection mechanism on the exhaust pipe 1, and the two ends of the multi-layer structure are covered by the extension of the two ends of the insulation layer 5.

[0023] Specifically, the heat storage material used in the heat storage layer 4 is relatively heavy, so the heat storage layer 4 can be connected to the main body of the vehicle frame, such as by using a connecting rod to lift the heat storage layer 4.

[0024] like Figure 2 As shown in the example, the preferred embodiment of this example includes a heat-conducting sleeve 6 that is attached to the outer circular surface of the exhaust pipe 1. The heat-conducting sleeve 6 is provided with a plurality of heat-conducting fins 7, which extend into the heat storage layer 4 to improve the heat transfer efficiency from the exhaust pipe 1 to the heat storage layer 4.

[0025] like Figure 2 As shown, in this example, preferably, the heating layer 3 is a spiral electromagnetic coil 8 sleeved on the outer circular surface of the heat-conducting sleeve 6, and the plurality of heat-conducting fins 7 form a continuous spiral shape, with the electromagnetic coil 8 inserted inside the heat-conducting fins 7.

[0026] like Figure 2 As shown in this example, preferably, the outer surface of the electromagnetic coil 8 is wrapped with a heat insulation sleeve 9, which insulates the electromagnetic coil 8 from a certain amount of heat, thus preventing excessively high temperatures from affecting the operation of the electromagnetic coil 8.

[0027] In this example, preferably, the gap between the heat-conducting sleeve 6 and the exhaust pipe 1 is filled with heat-conducting grease or heat-conducting adhesive, and the seal between the heat-conducting fins 7 and the heat storage layer 4 is filled with heat-conducting grease or heat-conducting adhesive.

[0028] like Figure 1 As shown, in this example, preferably, the distance between two adjacent heat-conducting fins 7 is less than the width of the heat-conducting fin 7.

[0029] like Figure 1 and Figure 2 As shown, in the initial stage of diesel engine startup, the temperature inside the exhaust pipe 1 is low. At this time, the power supply of the electromagnetic coil 8 is turned on, causing it to generate a high-frequency electromagnetic field, thereby heating the metal exhaust pipe and rapidly raising its temperature. This effectively prevents urea crystallization on the inner wall of the exhaust pipe 1 during the initial stage of vehicle startup. When the diesel engine is idling, the temperature of the exhaust pipe 1 will decrease. At this time, the electromagnetic coil 8 can also heat the exhaust pipe 1 to avoid urea crystallization. When the diesel engine is operating normally, the temperature of the exhaust pipe is high. In this state, no additional heating is required. Instead, the heat is transferred to the heat storage layer 4 through the heat-conducting layer 2 and the heat-conducting fins 7. The heat storage layer 4 absorbs the heat. When the diesel engine starts idling, the heat can be transferred back to the exhaust pipe 1 through the heat storage layer 4. At this time, the electromagnetic coil 8 is not required for heating.

[0030] By setting a multi-layer structure on the outside of the exhaust pipe 1, the temperature of the exhaust pipe 1 during engine operation is guaranteed, thereby effectively reducing urea crystallization and affecting the quality of the exhaust pipe 1.

[0031] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A urea anti-crystallization device for an SCR system, characterized in that: It includes a multi-layer structure wrapped around the exhaust pipe, consisting of a heat-conducting layer, a heating layer, a heat storage layer, and a heat insulation layer from the inside out, with the heat-conducting layer and the heat storage layer connected together; The heat-conducting layer includes a heat-conducting sleeve that is attached to the outer circular surface of the exhaust pipe. The heat-conducting sleeve is provided with a plurality of heat-conducting fins that extend into the heat storage layer. The heating layer is a spiral electromagnetic coil sleeved on the outer circumference of the heat-conducting sleeve. The plurality of heat-conducting fins form a continuous spiral shape, and the electromagnetic coil is inserted into the heat-conducting fins.

2. The SCR system urea anti-crystallization device according to claim 1, characterized in that: The outer circular surface of the electromagnetic coil is covered with an insulating sleeve.

3. The SCR system urea anti-crystallization device according to claim 1, characterized in that: The gap between the heat-conducting sleeve and the exhaust pipe is filled with heat-conducting grease or heat-conducting adhesive, and the seal between the heat-conducting fins and the heat storage layer is filled with heat-conducting grease or heat-conducting adhesive.

4. The SCR system urea anti-crystallization device according to claim 1, characterized in that: The distance between two adjacent heat-conducting fins is less than the width of the heat-conducting fins.

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