Rotational flow heating system for accelerating urea decomposition

Abstract

The utility model belongs to the technical field of commercial vehicle emission, and particularly relates to a rotational flow heating system for accelerating urea decomposition. The rotational flow heating system comprises an electric heater, one end of the electric heater is connected with a front air inlet round flange through a cylinder, the other end of the electric heater is connected with a mixer air inlet round flange through an air outlet round flange, a center shaft is arranged in the center of the electric heater, and one end of the center shaft is located in a turbofan. The other end of the spring penetrates through the electric heater and is locked and fixed through a locking nut; two high-temperature-resistant bearings are arranged in a central mounting hole of the turbofan and are positioned between a shaft shoulder of the central shaft and the turbofan; a bearing cover plate used for sealing the high-temperature bearing is arranged at the open end of the turbofan. According to the rotational flow heating system, the electric heater device is additionally arranged at the front end of the SCR, the air flow exhaust temperature is increased, and the problems that the exhaust temperature is insufficient (lower than 200 DEG C) under cold start, and a urea nozzle does not work are solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the commercial vehicle emission technical field, and specifically relates to a rotational flow heating system for accelerating urea decomposition. BACKGROUND

[0002] With the increasingly stringent Stage VI emission regulations for motor vehicles, the problem of urea crystallization of commercial vehicle aftertreatment products is increasing. At the same time, in order to cope with the upcoming Stage VII cold start emission limit problem, the traditional rotational flow tube assembly in the existing mixer has limited breaking capacity for urea droplets and exhaust gas, and urea droplets cannot be decomposed in time, which easily forms urea crystallization in local area, affecting engine performance.

[0003] The urea in the existing market SCR system needs to be injected when the exhaust temperature in the pipeline reaches about 200 DEG C, and participates in the catalytic reduction reaction of SCR, so it cannot meet the NOx emission limit under low temperature cold start. X In addition, due to the existence of local vortex or low gas flow area after urea injection point, urea solution spray condenses into wet wall, water evaporates under heat, forms crystals, and the crystals gradually grow, which can block the exhaust pipe or cause poor urea atomization, urea cannot be completely evaporated and decomposed, and crystals are left on the exhaust pipe wall, or large droplets reach the catalyst surface and cannot be evaporated and decomposed, forming crystals on the catalyst surface and blocking the catalyst pores. SUMMARY

[0004] The utility model aims at overcoming the shortcomings in the prior art, and provides a rotational flow heating system for accelerating urea decomposition.

[0005] To achieve the above technical purposes, the utility model embodiment adopts the technical scheme of:

[0006] A rotational flow heating system for accelerating urea decomposition, comprising an electric heater, one end of the electric heater is connected with a front air inlet circular flange through a cylindrical body, the other end of the electric heater is connected with a mixer air inlet circular flange through an air outlet circular flange, a center shaft is arranged in the center of the electric heater, one end of the center shaft is located in the inside of a vortex fan, the other end of the center shaft passes through the electric heater and is locked and fixed by a locking nut;Two high-temperature resistant bearings are arranged in the center mounting hole of the vortex fan, and the two high-temperature resistant bearings are positioned between the shaft shoulder of the center shaft and the vortex fan;The opening end of the vortex fan is provided with a bearing cover plate for sealing the high-temperature resistant bearing.

[0007] Further, one end of the cylinder body is connected with the engine through the front air inlet flange, and the other end is connected with the mixer through the mixer air inlet flange, the air inlet end of the mixer is provided with a urea nozzle, and the air outlet end is provided with a tail pipe, and the front end of the tail pipe is sequentially provided with an SCR catalyst and an ASC catalyst.

[0008] Further, the circular flange sealing gasket is arranged between the air outlet circular flange and the mixer air inlet circular flange, and the air outlet circular flange, the circular flange sealing gasket and the mixer air inlet circular flange are fixedly connected through the clamp.

[0009] Further, the periphery of the electric heater is wrapped with heat insulation cotton, and the outer side of the heat insulation cotton is provided with a heater heat insulation cover, and a hole is formed in the heater heat insulation cover, and the positive and negative electrodes of the electric heater are connected with the power supply through the hole.

[0010] Further, when the locking thread on the central shaft is a right-handed thread, the turbofan rotates counterclockwise, and when the locking thread on the central shaft is a left-handed thread, the turbofan rotates clockwise.

[0011] The beneficial effects brought by the technical scheme provided by the embodiment of the utility model are:

[0012] 1. The cyclone heating system of the utility model increases an electric heater device at the front end of the SCR, improves the air flow temperature, and makes up for the problem of insufficient exhaust gas temperature (lower than 200 DEG C) and non-working urea nozzle in cold start.

[0013] 2. The cyclone heating system of the utility model increases a turbofan structure at the front end of the electric heater, and the airflow passing through the turbofan can blow the turbofan, and the heat generated by the electric heater is concentrated and blown to the urea injection area in front of the SCR carrier.

[0014] 3. The cyclone heating system of the utility model can disturb the airflow by rotating the turbofan, increase the pressure of the urea atomization area, improve the atomization degree of the urea solution sprayed by the lifting nozzle and the exhaust gas, effectively reduce the crystallization risk, and reduce the dependence on the rear cyclone plate.

[0015] 4. The turbofan blade fixing bracket of the cyclone heating system of the utility model is shared with the electric heater support, and the manufacturing cost is saved.

[0016] 5. The turbofan and the electric heater of the cyclone heating system of the utility model are designed as a detachable structure, which is convenient for replacement and maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is the appearance view of the cyclone heating system in the embodiment of the utility model.

[0018] Figure 2 It is the main sectional view of the cyclone heating system in the embodiment of the utility model.

[0019] Figure 3 This is an exploded view of the swirl heating system in an embodiment of this utility model.

[0020] Figure 4 This is a side view of the swirl heating system in an embodiment of this utility model.

[0021] Figure 5 yes Figure 1 A schematic diagram of the central shaft in a swirling heating system.

[0022] Explanation of reference numerals in the attached drawings: 1-Inlet round flange; 2-Heater heat insulation cover; 3-Heat insulation cotton; 4-Outlet round flange; 5-Round flange gasket; 6-Mixer inlet round flange; 7-Turbine fan; 8-Bearing cover plate; 9-Lock nut; 10-Central shaft; 11-High temperature resistant bearing; 12-Cylindrical body; 13-Electric heater; 14-SCR catalyst; 15-ASC catalyst; 16-Tailpipe; 17-Urea nozzle. Detailed Implementation

[0023] In the description of this utility model, it should be understood that the directional terms such as "inner" and "outer", "upper" and "lower", "left" and "right" indicate the orientation or positional relationship, which are usually 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. Unless otherwise stated, these directional terms 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, and therefore should not be construed as limiting the scope of protection of this utility model.

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0025] Example 1

[0026] like Figures 1-5 As shown, a cyclone heating system for accelerating urea decomposition includes an electric heater 13. One end of the electric heater 13 is connected to the inlet flange 1 via a cylindrical body 12, and the other end of the electric heater 13 is connected to the inlet flange 6 of the mixer via an outlet flange 4. A central shaft 10 is provided at the center of the electric heater 13. One end of the central shaft 10 is located inside the turbofan 7, and the other end passes through the electric heater 13 and is locked and fixed by a locking nut 9. Two high-temperature bearings 11 are provided in the central mounting hole of the turbofan 7. The high-temperature bearings 11 are positioned between the shoulder of the central shaft 10 and the turbofan 7. A bearing cover plate 8 for sealing the high-temperature bearings 11 is provided at the open end of the turbofan 7.

[0027] One end of the cylinder 12 is connected with the engine through the front air inlet circular flange 1, and the other end is connected with the mixer through the mixer air inlet circular flange 6, the air inlet end of the mixer is provided with a urea nozzle 17, the air outlet end is provided with a tail pipe 16, and the front end of the tail pipe 16 is sequentially provided with an SCR catalyst 14 and an ASC catalyst 15.

[0028] The circular flange sealing pad 5 is arranged between the air outlet circular flange 4 and the mixer air inlet circular flange 6, and a clamp is arranged on the periphery to be connected. The whole mixer system is installed at the rear end of the rotational flow heating system, the exhaust gas discharged from the engine passes through the rotational flow heating system, then passes through the mixer system and the SCR catalyst and the ASC catalyst in the SCR mixing system, and finally is discharged from the tail pipe.

[0029] The periphery of the electric heater 13 is wrapped with the heat insulation cotton 3, and the outer side of the heat insulation cotton 3 is provided with the heater heat insulation cover 2, so as to reduce the heat transfer to the outside, the heater heat insulation cover 2 is provided with a hole, and the positive and negative electrodes of the electric heater 13 are connected with the power supply through the hole.

[0030] When the locking thread on the central shaft 10 is right-handed thread, the turbofan 7 rotates counterclockwise, and when the locking thread on the central shaft 10 is left-handed thread, the turbofan 7 rotates clockwise.

[0031] The turbofan 7 is U-shaped, and the open end is arranged close to the electric heater 13.

[0032] The working principle of the utility model is that:

[0033] The function of the mixer is to fully mix the tail gas and the urea solution, so as to ensure that the urea solution reacts with nitrogen oxides after decomposing ammonia, in the SCR system, the mixer can improve the uniform distribution of ammonia and reduce the risk of urea crystallization, however, the crushing capacity of the mixer for the urea solution and the tail gas is limited in the low-temperature cold start stage, and the emission requirements of future national seven cannot be met. If the urea is injected at low temperature, the risk of pipe wall crystallization will be increased, and the effective catalytic temperature range cannot be reached, and the SCR catalytic effect is poor.

[0034] The utility model discloses a heating system of accelerated urea decomposition installs in the front end of SCR mixer, when the automobile cold start, the vortex fan 7 is blown down under the exhaust gas flow, rotates by oneself, when the temperature of SCR upstream T6 and downstream T7 is less than 180 DEG C, the electric heater 13 heats with 100% power, when the temperature of SCR upstream T6 and downstream T7 is between 180-250 DEG C, the electric heater 13 heats according to the demand duty cycle of calculation, when the temperature of SCR upstream T6 and downstream T7 is greater than 250 DEG C, the electric heater 13 stops heating, and the vortex fan 7 stops working. Vortex fan 7 stirs the exhaust gas of engine discharge through rotating from the front end, discharges from the other side of vortex fan 7, and the helical airflow is heated through the electric heater 13, and the temperature is greatly improved, and the disturbed airflow also increases the pressure of urea atomization area, improves the atomization degree of urea solution and exhaust gas of urea nozzle 17, effectively reduces the crystallization risk, reduces the dependence on rear swirl plate, when using a certain length of time, when the vortex fan wheel needs to be replaced, only need to remove the heating section's front air circle flange 1 and the air outlet circle flange 4 from the front and rear assembly pipeline, and the vortex fan can be replaced.

[0035] Finally, it should be noted that the above specific embodiments are merely used to illustrate the technical solutions of the present application rather than limiting the present application. Although the present application has been described in detail with reference to the examples, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A cyclone heating system for accelerating the decomposition of urea, characterized in that, The electric heater (13) is connected with the front air inlet circular flange (1) through a cylinder (12) at one end, and connected with the mixer air inlet circular flange (6) through an air outlet circular flange (4) at the other end, and a center shaft (10) is arranged in the center of the electric heater (13), one end of the center shaft (10) is located inside a turbofan (7), the other end passes through the electric heater (13) and is locked and fixed through a locking nut (9); two high-temperature resistant bearings (11) are arranged in the center mounting hole of the turbofan (7), and the two high-temperature resistant bearings (11) are positioned between the shaft shoulder of the center shaft (10) and the turbofan (7); the opening end of the turbofan (7) is provided with a bearing cover plate (8) for sealing the high-temperature resistant bearing (11).

2. The vortex heating system for accelerating urea decomposition according to claim 1, wherein, One end of the cylinder (12) is connected with the engine through the front air inlet circular flange (1), and the other end is connected with the mixer through the mixer air inlet circular flange (6), the air inlet end of the mixer is provided with a urea nozzle (17), and the air outlet end is provided with a tail pipe (16), and the front end of the tail pipe (16) is sequentially provided with an SCR catalyst (14) and an ASC catalyst (15).

3. The vortex heating system for accelerating urea decomposition of claim 1, wherein, A circular flange sealing gasket (5) is arranged between the air outlet circular flange (4) and the mixer air inlet circular flange (6), and the air outlet circular flange (4), the circular flange sealing gasket (5) and the mixer air inlet circular flange (6) are fixedly connected through a clamp.

4. The vortex heating system for accelerating urea decomposition of claim 1, wherein, The periphery of the electric heater (13) is wrapped with heat insulation cotton (3), the outer side of the heat insulation cotton (3) is provided with a heater heat insulation cover (2), a hole is formed in the heater heat insulation cover (2), and the positive and negative electrodes of the electric heater (13) are connected with an external power supply through the hole.

5. The vortex heating system for accelerating urea decomposition of claim 1, wherein, When the locking thread on the center shaft (10) is right-handed thread, the turbofan (7) rotates counterclockwise; when the locking thread on the center shaft (10) is left-handed thread, the turbofan (7) rotates clockwise.

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