CN220319653U - Prevent cryogenic urea liquid feeding device - Google Patents

Abstract

The utility model provides a prevent cryogenic urea liquid feeding device, includes module body, urea liquid feed pump, urea liquid level sensor, urea liquid temperature sensor, heating defrosting circulating water pipe, water inlet connector, play water connector, the feed pump is equipped with at least one gas space and pressure release device, and when the volume expansion is frozen to the working liquid, gas space and pressure release device are used for resisting the expansion of liquid icing to the spalling circulating water system when preventing that water is frozen.

Description

Prevent cryogenic urea liquid feeding device

Technical Field

The utility model belongs to the field of engine emission control, and particularly relates to a urea solution supply metering system of an engine exhaust selective reduction (SCR) technology.

Background

With the increasing prominence of environmental problems, energy conservation and emission reduction have become ever-endless demands for vehicles and engines, and for this reason, a series of vehicle emission standards are being put out in various countries, and are becoming more and more strict. For this purpose, internal combustion engine powered vehicles require the installation of an exhaust aftertreatment system in order to meet the emission requirements. For example, SCR (Selective Catalytic Reduction) technology, which is mainly used for catalytic treatment of pollutants such as NOx in diesel engine exhaust gas, has become a technology that is required for diesel vehicles and the like.

SCR technology requires the quantitative injection of NOx reduction reagent into the diesel exhaust, which has a 32.5% strength by weight aqueous urea solution (also called diesel exhaust treatment solution def= Diesel Exhaust Fluid, or blue addition solution AdBlue), or ammonia. In the catalytic treatment process of SCR exhaust, DEF treatment liquid is quantitatively injected into diesel engine exhaust, and is decomposed into ammonia gas at high temperature through the exhaust, and the ammonia gas is mixed with the exhaust and then enters an SCR catalytic converter, and under the action of a catalyst, the ammonia gas and NOx and the like in the engine exhaust are subjected to catalytic reduction reaction, so that the NOx is decomposed into harmless N2 and H2O. If the amount of DEF injected does not match the NOx content in the exhaust gas or the urea solution quality is not satisfactory, either the NOx cannot be fully reduced and decomposed, the emission is increased, or a large amount of ammonia remains to be discharged to the atmosphere, causing secondary pollution.

However, the quality of the urea aqueous solution as an important reagent is often controlled only at the time of shipment or inspection, and a device capable of detecting the quality of the urea aqueous solution is not provided in many post-treatment systems. In order to reduce the use cost, a plurality of vehicle users use an inferior urea solution or add an aqueous solvent into the urea solution, so that the quality of the urea solution is uneven, the treatment effect of tail gas NOx is seriously affected, and the SCR is similar to a dummy. Therefore, it is necessary to provide a sensor in the device that can detect the urea quality.

In addition, due to the characteristics of the urea aqueous solution, after the injection is finished, the urea mixed solution remained in the closed urea system and the closed urea system pipeline may be frozen below the freezing point (-11-12 ℃) of the urea solution, so that the urea injection is interrupted, and the urea injection system is damaged due to expansion of the urea solution volume during the freezing. Most of the existing SCR technology considers that an auxiliary heating device is additionally arranged to ensure that the system works normally. However, the existing devices for providing a spray power source are too bulky or otherwise difficult to integrate into the DEF tank, and often require a complex design of the ice melting device, which makes the system more bulky and difficult to deploy, and the more complex the system is, the higher the cost will be. Particularly for an injection system arranged in a urea pump, the urea pump is often arranged close to the bottom of the box body, the urea pump does not have defrosting capacity, and the urea pump needs to thoroughly defrost the system to start working, so that the thawing time and arrangement space of the system are limited. For example, US20090301067A1 discloses a metering jet device and a method thereof. The metering and injection device is a solenoid-driven plunger pump nozzle mounted on the exhaust pipe, requiring the addition of a low pressure pump to provide working fluid from the DEF reservoir, and is not able to function properly without the assistance of a special ice melting and nozzle cooling device. Additionally, U.S. patent No. 8356471B2 discloses an operation, system and method for SCR metered injection that provides a pump-nozzle tip separate control scheme. In addition to the stringent requirements for temperature control of the device and for the deicing of the pipeline, the metering accuracy thereof also needs to be precisely controlled.

For the whole urea injection device, a gas space is reserved at the top of the urea box, and the space not only can ensure the normal exhaust of each execution part, but also can ensure that the urea box has enough expansion space when the urea solution freezes. The urea can not be accurately judged when being filled, the existing structure is commonly additionally provided with a pipeline communicated with the atmosphere, but is in the way of the dirt bearing capacity of the system, and a filtering device is required to be additionally arranged, so that the complexity and the cost of the system are further increased.

In summary, the precision and stability of NOx Selective Catalytic Reduction (SCR) technology, whether it is a simplified construction and application, or its metering injection system, is a very valuable research effort.

Disclosure of Invention

The present utility model aims to solve the above problems, and an object of the present utility model is to provide a urea solution supply device that has a simple structure, good adaptability, stable operation, and low cost.

In order to achieve the above purpose, the present utility model adopts the following technical scheme: a urea solution supply device comprises a urea solution supply pump, a metering nozzle, a module body, a urea solution liquid level sensor, a urea solution temperature sensor, a urea solution quality sensor and a urea solution heating and thawing circulating water pipe.

When the liquid in the urea liquid supply pump freezes to generate an expansion volume, one part of the expansion volume is released by compressing the gas in the gas space, and the other part of the expansion volume is discharged by the pressure release device, so that the damage of parts caused by freezing of the liquid is prevented.

The gas space may also be a closed hollow volume made of a soft, thin-walled material, which is compressed to release the volume when the ambient pressure increases. The closed hollow volume is made of rubber material.

The gas space of the supply pump and the pressure relief device are arranged on the same side, and when the volume of the allowable liquid released by the gas space for icing and expanding is insufficient, the pressure relief device is opened under pressure, and the solution is discharged.

In the above structure, when the temperature is returned to defrost, the peripheral pressure is reduced due to the discharge of the liquid, and the hollow volume of the gas space is deformed.

The module body is further provided with a urea liquid outlet connector, a liquid return connector, an internal liquid outlet channel and a liquid return channel, the heating defrosting circulating water inlet and outlet connectors and a mounting buckle for mounting and fixing the module into the urea box after the module is inserted into the urea box from the upper part of the urea box.

The liquid supply pump comprises a liquid inlet and a liquid outlet, wherein the liquid inlet is provided with a primary filter screen, and urea solution enters the supply pump after being filtered by the primary filter screen under the action of self gravity. The primary filter screen is provided with a vertical air exhaust bubble pipe, in addition, the middle part of the liquid supply pump is provided with a transverse air exhaust bubble pipe, and the two air exhaust bubble pipes are connected through a tee joint pipe and then lead to a space above the bottom plane of the module installation buckle. The tee joint part is provided with a part of primary filter screen so that when the urea solution is thawed after frozen ice, the part of primary filter screen which is thawed earliest can feed liquid into the urea solution supply pump.

Above-mentioned urea pump liquid outlet is connected with a drain pipe, and this drain pipe is the shaping pipe to the mode design of defrosting circulating water pipe is unfreezed in the heating as close as possible, the drain pipe stretches into inside and inside liquid channel intercommunication of module body, and leads to out the liquid and connect the mouth. A sealing gasket is arranged between the liquid outlet pipe and the liquid outlet channel, so that sealing and shock absorption are performed.

The following technical solutions further define or optimize the present utility model.

The beneficial effects of the utility model are as follows: when adopting simple structure installation and arrange convenient straight barrel type exhaust mixing pipe, reduce the crystallization risk in the engine blast pipe, improve reactant and exhaust mixing degree of consistency, can reduce SCR system cost simultaneously.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of a low-temperature-freezing-preventing urea solution supply device provided by the utility model.

Fig. 2 is a schematic diagram of a urea solution supply apparatus for preventing low-temperature freezing according to a second embodiment of the present utility model.

Fig. 3 is a schematic diagram of a third embodiment of a urea solution supply apparatus for preventing low-temperature freezing according to the present utility model.

FIG. 4 is a partial cross-sectional view of a gas space structure provided by the present utility model.

FIG. 5 is a second partial cross-sectional view of a gas space structure provided by the present utility model.

Fig. 6 is a schematic structural diagram of a pressure relief device according to the present utility model.

Detailed Description

The utility model is further described below with reference to the drawings and examples.

The first embodiment of the present utility model is schematically shown in fig. 1, and the urea solution supply device includes a urea tank 13, a urea solution supply pump 12, a metering nozzle 11, a module body 10, a urea solution level sensor 43, a urea solution temperature sensor 44, a urea solution quality sensor 38, a urea solution heating and thawing circulating water pipe 45, and a urea cleaning device 14.

The module body 10 is provided with a urea solution outlet nozzle 20, a liquid return nozzle 25, water inlet and outlet nozzles (46, 47) of the heating and thawing circulating water pipe 45, a secondary urea solution filtering device 52 arranged at the upstream of the outlet nozzle 20, and a mounting buckle 16 for mounting and fixing the module 15 to the urea tank 13 after the module 15 is inserted into the urea tank 13 from the upper part of the urea tank 13. In addition, the module body 10 itself includes an internal drain channel 57 and return channel 26, an internal access channel (as shown in fig. 4, taking the access channel 300 as an example), and a circumferential array of trapezoidal steps 58. The mounting buckle 16 comprises a limit hole 54a matched with a step 58 of the module body 10, a protrusion 54 matched with a limit step 59a of the urea tank 13 and a through hole 55 allowing each pipeline of the urea liquid supply device 15 to pass through, the mounting buckle 16 is fixed on the module body 10 in a clasping manner, simultaneously limits each pipeline leading to the inside of the body and each sensor pipeline, ensures the stability of each mounting component, and mounts the module 15 in the urea tank mounting hole 59 through the protrusion 54.

The secondary urea solution filter 52 is located upstream of the outlet nozzle 20 and includes a chamber 52a with a threaded cap 52b and an inner filter cartridge 52 disposed within the chamber 52 a. The cavity 52a is communicated with the inner liquid outlet channel 57, and urea liquid is filtered by the filter element 52 and then output. The filter element 52 can be replaced periodically with a higher filtering precision than the primary filter screen 32 to ensure proper operation of the downstream metering nozzle 11 and to increase the service life of the system.

The liquid supply pump 12 comprises a liquid inlet 60 and a liquid outlet 29, the liquid inlet 60 is provided with a primary filter screen 32, and urea solution enters the liquid supply pump 12 after being filtered by the primary filter screen 32 under the action of self gravity. The primary screen 32 is clamped onto the feed pump 12 by means of a snap 31, on which a vertical exhaust bubble tube 33 is provided. In addition, a transverse bubble discharging pipe 30 is arranged in the middle of the feed pump 12, and the two bubble discharging pipes (30, 33) are connected through a three-way connecting pipe 41 and then lead to an air gap space above the bottom plane of the module mounting buckle 16. The three-way connection pipe 41 is partially provided with a partial primary filter screen 41a so that the urea solution supply pump 12 can be fed with liquid through the partial primary filter screen 41a which is thawed earliest when the urea solution is thawed after frozen ice.

Further, as shown in fig. 5 and 6, the liquid outlet 29 of the feed pump 12 includes a step 401 with a flange 400, a pressing cover 403 cooperating with the step, and the pressing cover 403 includes a barb 404. The barb 404 is clamped on the flange 400, and a sealing cavity 406 is formed by the sealing ring 402, and a gas space 405 is arranged in the cavity 406. The gas space 405 is a closed hollow volume made of a soft thin-walled material, which may be rubber.

The gas space 405 is arranged on the same side as the pressure relief device 407, and the pressure relief device 407 is used for counteracting the volume of the expansion part and balancing the pressure. The pressure relief device 407 is a single valve structure, and includes a pressure relief flow passage 414, a base 413, a valve element 410, a sealing seat 412, and a valve spring 415. In a normal working state, the pressure relief device 407 is closed, when the internal working liquid freezes at a low temperature, the internal volume expands, the pressure causes the check valve to open, and the fluid is discharged from the pressure relief flow passage 414.

The gas space 405 and the pressure relief device 407 may also be present separately.

The metering nozzle 11 comprises a liquid inlet end 23 and a liquid return end 24, the liquid inlet end 23 is connected with the liquid outlet nozzle 20 through a liquid supply pipe 21, the liquid return end 24 is connected with the liquid return nozzle 25 through a liquid return pipe 22, and the other end of the liquid return nozzle 25 is communicated with a liquid return channel 26 and is led to a certain depth inside the urea tank 13 through the liquid return channel 26.

The liquid outlet 29 is connected with the liquid outlet channel 57 in the module body 10 through a liquid outlet pipe 28, the liquid outlet pipe 28 is a forming pipe, and is designed in a manner of being close to the heating defrosting circulating water pipe 45 as much as possible, a sealing gasket 56 is arranged between the liquid outlet pipe 28 and the liquid outlet channel 57, so that sealing and shock absorption are performed, and the liquid outlet channel 57 in the module body is led to the liquid outlet nozzle 20.

The urea solution supply pump 12 and the urea solution quality sensor 38 are positioned at the bottom of the module 15 and are fixed on a urea solution heating and thawing circulating water pipe 45 so as to be arranged in a manner of being beneficial to thawing ice. The urea solution heating and thawing circulating water pipe 45 is a bottom L-shaped pipe, and a platform 34 with a positioning hole 35 is arranged between the L-shaped pipes, so that the urea solution supply pump 12 and the urea solution quality sensor 38 are fixed at the same height position of the module 15, and can be inserted into the bottommost part of the urea tank 13 through a module mounting hole 59 of the urea tank 13. The quality sensor 38 includes a step 40 of threaded holes 40a corresponding to the positioning holes 35, and is fixed to the platform 34 by bolts 36. The urea solution level sensor 43 and the urea solution temperature sensor 44 are fixed by the module 15 and extend into the urea tank 13 close to the urea solution feed pump 12.

As shown in fig. 4, the heating and thawing circulating water pipe 45 is connected to the water inlet and outlet connectors (46, 47) of the heating and thawing circulating water pipe through a water inlet and outlet channel (for example, a water inlet channel 300) in the module body 10. On the water inlet and outlet channel 300 inside the module body 10, a gas space 301 is provided to prevent the spalling of the circulating water system when water is frozen. The end part of the heating and thawing circulating water pipe 45 is provided with a water pipe sleeve 302 and a damping sleeve 304, which are used for fixing and protecting the heating and thawing circulating water pipe 45, and the circulating water pipe 45 is sealed with the module body 10 through a sealing ring 303.

The urea cleaning device 14 comprises a diaphragm air pump 49 and a cleaning line 17. The module body 10 includes a gas path channel 48. The cleaning pipeline 17 comprises an air inlet channel 49a and an air outlet channel 51, and the air inlet channel 49a is communicated with the upper air space of the urea box 13 through the air channel 48 of the module body 10. The air outlet channel 51 is provided with a one-way valve 50 and is in one-way communication with the liquid outlet pipe 28. When necessary, the air pump 49 is started to suck air from the urea tank 13, pressurize the air, open the one-way valve 50, and make the pressurized air pass through the air inlet 49a, the liquid outlet 28, the liquid supply pipe 21 and the liquid return pipe 22 in sequence, and can pump most of the urea liquid in each pipeline back to the urea tank 13.

Fig. 2 is a schematic structural diagram of a second embodiment of the present utility model, which is different from the first embodiment of the present utility model in that: the module body 10 is provided with a urea pumping back device 18, which comprises a pumping back valve 100 and a pumping back pipeline 18a. The back-pumping pipeline 18a comprises an injection cavity 101, a drainage channel 104 which is communicated with the urea box 13 at a certain depth, a liquid inlet channel 103 and a liquid outlet channel 102. The back suction valve 100 is a one-way valve opened by electromagnetic force, and the injection cavity 101 is a space which is favorable for urea liquid to flow back from the drainage channel 104 quickly under the opened state of the back suction valve 100, and meanwhile, the space is favorable for liquid in the liquid outlet pipe 28 to enter the drainage channel 104. The urea back-pumping device 18 is connected in series with the internal liquid outlet channel 57 through the liquid inlet channel 103 and the liquid outlet channel 102, and in a normal injection state, urea liquid in the internal liquid outlet channel 57 directly reaches the liquid outlet nozzle 20 through the liquid inlet channel and the liquid outlet channel (102 and 103) of the urea back-pumping device 18 and is then output. When the pipeline cleaning is required, the back-pumping valve 100 is started, urea liquid enters the guide channel 104 through the liquid inlet channel 103 at a certain speed, so that the injection cavity 101 generates a certain vacuum degree, and most of the urea liquid in the liquid supply pipe 21 and the back-liquid pipe 22 is pumped back to the urea tank 13.

With the structure described in this embodiment, the extension section of the liquid return channel 26 inside the module is disposed in the gas space above the urea tank 13, so as to ensure that no suck-back phenomenon occurs in the pipeline during the suck-back process.

Fig. 3 is a schematic structural diagram of a third embodiment of the present utility model, which is different from the first embodiment of the present utility model in that: the module body 10 is provided with a urea box 13, an atmospheric pipeline 200 and a connector 201. The urea tank 13 is connected with the connector 201 at one end of the atmospheric pipeline, and the other end of the atmospheric pipeline extends into the urea tank 13 to a certain depth H, so that on one hand, when the filling port of the urea tank 13 is higher than the module body 10, excessive filling is prevented, and the urea liquid level is higher than a set position, and on the other hand, the atmospheric pressure in the urea tank 13 is balanced. In this embodiment, the air inlet 49a of the cleaning device can be directly connected to the atmosphere to simplify the design of the pipeline.

The above examples are only for illustrating the essence of the present utility model, but do not limit the present utility model. Any modifications, simplifications, etc., which do not depart from the principles of the utility model, are intended to be included within the scope of the utility model.

The utility model is not related in part to the same as or can be practiced with the prior art.

Claims (5)

1. The utility model provides a prevent low temperature freezing's urea liquid feeding device, includes module body, urea liquid feed pump, urea liquid level sensor, urea liquid temperature sensor, heating defrosting circulating water pipe, water inlet connector, play water connector, the inside circulating water runner that is provided with of module body, heating defrosting circulating water pipe passes through the circulating water runner with heating defrosting circulating water pipe water inlet connector is linked together, its characterized in that, be equipped with gas space and pressure relief device on the urea liquid feed pump, when the liquid freezes in the urea liquid feed pump and produces the expansion volume, a part is released the volume by the compression of gas in the gas space, and another part is discharged by pressure relief device to lead to the part damage when preventing that liquid freezes.

2. The urea solution supply apparatus according to claim 1, wherein the gas space is provided near the outlet to meet expansion space requirements after freezing of the working fluid in the module.

3. Urea solution supply device according to claim 2, characterized in that the supply pump gas space is arranged on the same side as the pressure relief device, which is pressurized to open and discharge the solution when the volume of the allowed liquid ice expansion released by the gas space is insufficient.

4. A urea solution supply apparatus according to claim 3, wherein the gas space is a closed hollow volume made of a soft thin-walled material, which is compressed to release the volume when the ambient pressure increases, and which is deformed when the ambient pressure decreases due to the discharge of the liquid during thawing at the return temperature.

5. The urea solution supply apparatus according to claim 4, wherein the closed hollow volume is made of a rubber material.