CN213088097U

CN213088097U - Novel anti-freezing SCR system

Info

Publication number: CN213088097U
Application number: CN202020559702.4U
Authority: CN
Inventors: 郑远师; 乐起奖; 陈锐
Original assignee: Fuai Electronics Guizhou Co ltd
Current assignee: Fuai Electronics Guizhou Co ltd
Priority date: 2020-04-16
Filing date: 2020-04-16
Publication date: 2021-04-30
Anticipated expiration: 2030-04-16

Abstract

The utility model provides a novel anti refrigerated SCR system, includes a urea case, a urea liquid feed pump, an SCR module body, a filter, a urea nozzle, a scavenging pump, the module body includes liquid outlet channel and returns the liquid passageway, the urea liquid feed pump is including supplying the liquid mouth, the urea nozzle includes feed liquor mouth and returns the liquid mouth, the liquid outlet channel one end of SCR module body is connected through a feed pipe to the liquid supply mouth, the liquid outlet channel other end is connected to the feed liquor mouth of urea nozzle through a high-pressure tube, forms urea solution supply flow channel, the liquid mouth that returns of urea nozzle is connected to the liquid passageway one end that returns of SCR module body through a liquid return pipe, return the liquid passageway other end and connect the urea incasement portion, form urea solution and return the liquid flow channel. The cleaning pump sucks the gas in the upper space of the urea box, blows in the urea solution supply channel, returns to the urea box through the urea solution backflow channel and brings out the residual urea solution in the pipeline.

Description

Novel anti-freezing SCR system

Technical Field

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

Background

Scr (selective Catalytic reduction) technology is currently a necessary technology for Diesel engine Exhaust treatment, and requires that a NOx reduction reagent, which is an aqueous urea solution with a concentration of 32.5% by weight (also called Diesel Exhaust Fluid DEF = Diesel Exhaust Fluid, or additive blue), or ammonia gas, be quantitatively injected into Diesel engine Exhaust. In the SCR exhaust gas catalytic treatment process, DEF treatment liquid is injected quantitatively into diesel engine exhaust gas, decomposed into ammonia gas by the exhaust gas at high temperature, mixed with the exhaust gas, and then introduced into an SCR catalytic converter, and the ammonia gas and NOx in engine exhaust gas undergo catalytic reduction reaction under the action of a catalyst, so that NOx is decomposed into harmless N2 and H2O.

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 pipeline is likely to freeze below the freezing point (-11-12 ℃) of the urea solution, which not only can cause the urea injection to be interrupted, but also can cause the urea injection system to be damaged due to the expansion of the urea solution during the freezing.

In the existing SCR technology, an auxiliary heating device is mostly considered to be additionally arranged to ensure the normal work of a system. However, the existing devices for providing a source of injection power are too bulky or otherwise difficult to integrate system components into the DEF reservoir, often requiring complex design of ice melting devices, which makes the system more bulky and difficult to deploy, and at the same time, the more complex the system, the higher the cost. Especially for the built-in injection system of urea pump, the urea pump is arranged and is often pressed close to the bottom of the box, and self does not have the ability of unfreezing, needs the system of thoroughly unfreezing just can begin to work, leads to the system all to receive the restriction on unfreezing time and arrangement space.

The other system adopts a back suction mode, and the system has the problems of long working time and incomplete back suction no matter the system generates vacuum to lead and cause backflow under the condition that a liquid supply pump continuously supplies liquid through a reversing valve or directly pumps back through the back suction pump, so that residual urea solution in a pipeline damages the system or influences the working effect due to icing and expansion.

In addition, a small amount of systems adopt a purging mode, but due to the space limitation of the systems, reasonable management design cannot be matched, so that residual urea solution in the systems cannot be cleaned up, and a purging pump is usually used as a common diaphragm pump and is easy to generate large noise.

In summary, the Selective Catalytic Reduction (SCR) technology is a very valuable research work, both in terms of simplified structure and application, and also in terms of accuracy and stability of its metered injection system.

Disclosure of Invention

The present invention is directed to solving the above problems, and an object of the present invention is to provide a urea solution supply module which has a simple structure, good environmental adaptability, stable operation and low cost.

In order to achieve the purpose, the invention adopts the following technical scheme: the device comprises a urea box, a urea liquid supply pump, an SCR module body, a filter and a urea nozzle.

The SCR module body comprises a liquid outlet channel and a liquid return channel. The urea liquid supply pump is a solenoid plunger pump driven by electromagnetic force and comprises a liquid supply nozzle. The urea nozzle is a measurable nozzle driven by electromagnetic force and comprises a liquid inlet nozzle and a liquid return nozzle.

The urea liquid supply pump is arranged at the bottom of the urea box, the liquid supply nozzle is connected with one end of a liquid outlet channel of the SCR module body through a liquid supply pipe, and the other end of the liquid outlet channel is connected with a liquid inlet nozzle of the urea nozzle through a high-pressure pipe. The liquid supply pipe, the liquid outlet channel and the high-pressure pipe form a urea solution supply flow channel. And the solution in the urea box is pumped out by a urea solution supply pump, conveyed to a urea nozzle through a supply flow channel and sprayed to an exhaust pipe by the urea nozzle, and the residual tail gas is treated.

The liquid return nozzle of the urea nozzle is connected to one end of a liquid return channel of the SCR module body through a liquid return pipe, and the other end of the liquid return channel extends into the urea box. The liquid return pipe, the liquid return channel and the liquid return channel extension section form a urea liquid return flow channel. And during the working process of the urea nozzle, the generated backflow liquid returns to the urea box again through the liquid return flow channel.

The filter is arranged on the supply flow passage and used for filtering urea solution at the front end of the urea nozzle so as to ensure the normal work of the urea nozzle. In a preferred embodiment, the module body includes a cartridge cavity, and the filter is mounted in the cartridge cavity. The filter element cavity is connected in series with a liquid outlet channel of the SCR module body and comprises a liquid inlet and a liquid outlet. The liquid outlet sets up in filter core chamber bottom position, the liquid outlet sets up in filter core chamber top position, and the sectional area of liquid outlet is far less than the sectional area of filter core chamber cavity to be favorable to cleaning the time filter core intracavity liquid discharge.

The novel anti-freezing SCR system comprises a scavenging pump, wherein the scavenging pump is a self-suction type air blowing pump. One end of the cleaning pump is connected with the liquid supply pipe, and the other end of the cleaning pump is connected with the gas space at the upper part of the urea box. The downstream of the scavenging pump comprises a liquid-isolating one-way valve which is connected in series with a pipeline between the liquid supply pipe and the scavenging pump, so that pressure liquid is prevented from entering the scavenging pump to cause damage. When the system finishes working and needs to clean the pipeline, the cleaning pump starts working to suck gas on the upper part of the urea box and generate air pressure, and the air flow enters the supply flow channel through the liquid isolating one-way valve, comprises the filter element cavity and then enters the liquid return flow channel through the urea nozzle to take out residual urea solution in the pipeline and the cavity.

A further refinement of the new anti-freeze SCR system described above provides that the urea solution feed pump comprises an expansion space and a pressure relief valve. The expansion space is arranged at a position close to the liquid supply nozzle and is a space body capable of deforming according to pressure, and a cavity of the expansion space is communicated with the liquid supply nozzle channel. When the freezing volume of the circulating water or the working liquid expands, the gas in the gas space is compressed to release the volume, so that the damage of parts caused by the freezing of the liquid is prevented, and the total volume of the gas space is more than or equal to the expansion volume of the liquid in the supply module when the liquid freezes.

The pressure relief valve is a one-way valve which is opened by pressure and is arranged near the liquid supply nozzle. The pressure release valve is a ball valve and comprises a valve ball, a valve seat and a valve spring, one end of the pressure release valve is communicated with the outside (in the urea box), and the other end of the pressure release valve is connected with a cavity of the expansion space or a liquid supply channel. When the liquid pressure is increased to be larger than the opening pressure of the pressure relief valve due to the blockage of a certain section of the supply flow channel, the pressure relief valve is opened to relieve the pressure, the pressure in the flow channel is maintained to be normal, and the pipeline is prevented from being damaged due to the continuous increase of the pressure.

The following technical solutions further define or optimize the present application.

Drawings

FIG. 1 is a schematic diagram of a novel anti-freezing SCR system according to the present invention.

FIG. 2 is a schematic diagram of a urea solution supply pump of the novel anti-freezing SCR system provided by the present invention.

Detailed Description

The invention is further described below with reference to the figures and examples.

The structural schematic diagram of the SCR system provided by the present application is shown in fig. 1, and includes a urea tank 4, a urea liquid supply pump 8, an SCR module body 1, a filter 109, a urea nozzle 2, a scavenging pump 5, and a liquid-proof check valve 6. The filter 109, the cleaning pump 5 and the liquid-isolating check valve 6 are arranged on the SCR module body 1, the urea liquid supply pump 8 is arranged at the bottom of the urea tank 4, and the urea nozzle 2 is mounted on an exhaust pipe (not shown).

The SCR module body 1 comprises a liquid outlet channel 108, a liquid return channel 110, a filter element cavity 115, a circulating cooling water pipe 7 arranged inside the urea box 4, a liquid level sensor 102, a temperature sensor 103 and a quality sensor 101. The filter element cavity 115 is connected in series in the liquid outlet channel 108, and the filter 109 is installed in the filter element cavity 115 and used for filtering the urea solution output to the urea nozzle 2. The filter element cavity 115 comprises a liquid inlet 104 and a liquid outlet 107, the liquid inlet 104 is arranged at the bottom of the filter element cavity 115, the liquid outlet 107 is arranged at the top of the filter element cavity 115, and the sectional area of the liquid outlet 107 is far smaller than that of the filter element cavity 115, so that liquid in the filter element cavity 115 can be discharged when cleaning is facilitated. The filter 109 is mounted in a cartridge chamber 115 and is secured and sealed by a threaded cap 105 with a gasket 106.

The urea solution supply pump 8 is a solenoid plunger pump driven by electromagnetic force and comprises a liquid supply nozzle 100, the urea solution supply pump 8 and the circulating cooling water pipe 7 are arranged on the same side, and the urea solution supply pump 8 is close to the circulating cooling water pipe 7 in a mode of being beneficial to melting ice.

Further, the urea liquid supply pump 8 is provided with a separate antifreeze structure, as shown in fig. 2, including an expansion space 8a and a relief valve 8 b. The expansion space 8a is disposed near the liquid supply nozzle 100 and communicates with the liquid supply passage 100a of the liquid supply nozzle 100 through a cavity passage A206. The expansion space 8a comprises a step 211 with a flange 204, a gland 201 cooperating with the step 211, said gland 201 comprising a barb 200. The barb 200 is clamped on the flange 204 and forms a sealed cavity with a gas space 203 by means of a sealing ring 202. The gas space 203 is a closed hollow volume made of a soft thin-walled material, which may be rubber. The pressure release valve 8B is a one-way valve that opens by pressure, and is disposed near the liquid supply nozzle 100, with one end leading to the outside (inside the urea tank 4), and the other end connected to the cavity of the expansion space 8a through a cavity passage B207. The pressure relief valve 8b is a ball valve, and includes a valve ball 209, a valve seat 208, and a valve spring 210. The spring force of the valve spring 210 acts on the valve ball 209 to ensure that the relief valve 8b is closed in a normal state, and the opening pressure of the relief valve 8b can be set by adjusting the spring force of the valve spring 210. When the liquid pressure is increased to be larger than the opening pressure of the pressure relief valve 8b due to the blockage of a certain section of the supply flow channel (116, 108 and 114), the pressure relief valve 8b is opened to relieve the pressure, so that the pressure in the flow channel is maintained to be normal, and the pipeline is prevented from being damaged due to the continuous increase of the pressure.

The urea nozzle 2 is a metering nozzle driven by electromagnetic force, and comprises a liquid inlet nozzle 113 and a liquid return nozzle 112.

The liquid supply nozzle 100 is connected to one end of a liquid outlet channel 108 of the SCR module body 1 through a liquid supply pipe 116, and the other end of the liquid outlet channel 108 is connected to a liquid inlet nozzle 113 of the urea nozzle 2 through a high pressure pipe 114. The liquid supply pipe 116, the liquid outlet passage 108 and the high-pressure pipe 114 constitute a urea solution supply flow passage (116, 108, 114). The solution in the urea tank 4 is pumped by the urea solution supply pump 8, is delivered to the urea nozzle 2 through the supply flow channels (116, 108, 114), and is sprayed to the exhaust pipe (not shown) from the urea nozzle 2 for exhaust gas treatment.

The liquid return nozzle 112 of the urea nozzle 2 is connected to one end of a liquid return channel 110 of the SCR module body 1 through a liquid return pipe 111, and the other end of the liquid return channel 110 extends to the inside of the urea tank 4. The liquid return pipe 111, the liquid return channel 110 and the liquid return channel extension section 110a form a urea liquid return flow channel (111, 110 a). The return liquid generated during the operation of the urea nozzle 2 returns to the urea tank 4 through the return liquid flow passage (111, 110 a).

The scavenging pump 5 is a self-suction type air blowing pump. One end of the cleaning pump 5 is connected with the liquid supply pipe 116, and the other end is connected with the upper gas space 203 of the urea box 4. The downstream of the scavenging pump 5 comprises a liquid-isolating one-way valve 6 which is connected in series with a pipeline between the liquid supply pipe 116 and the scavenging pump 5 to prevent pressure liquid from entering the scavenging pump 5 to cause damage.

The operation of the novel anti-freezing SCR system is as follows.

The system judges whether the injection is required to be executed according to the condition of the engine and the condition of data input by each sensor (101, 102, 103), when the condition is met, the system drives the urea liquid supply pump 8 to work to generate pressure urea solution, fills the liquid supply nozzle 100, the expansion space 8a and the cavity of the pressure relief valve 8b, then enters the liquid supply pipe 116 through the liquid supply nozzle 100, is filtered by the liquid outlet channel 108 and the filter 109 in the filter element cavity 115 and then is conveyed to the high-pressure pipe 114, the urea solution in the high-pressure pipe 114 reaches the urea nozzle 2, and the urea nozzle 2 starts to work and injects the urea solution. Part of the returned liquid is returned to the urea tank 4 through a return flow path (111, 110 a).

When the system finishes working and needs to clean the pipeline, the cleaning pump 5 executes working to suck gas on the upper part of the urea box 4 and generate air pressure, the air flow enters a supply flow channel including a filter element cavity 115 through the liquid isolating one-way valve 6 and then enters a liquid return flow channel (111, 110 and 110 a) through the urea nozzle 2 to take out residual urea solution in the pipeline and the cavity.

For the urea solution in the urea solution supply pump 8, when the urea solution is frozen at low temperature, the gas space 203 of the expansion space 8a is compressed, and a space required for allowing the liquid in the urea solution supply pump 8 to be frozen to increase in volume is released, so that the urea solution supply pump 8 is prevented from being damaged due to the expansion of the liquid volume. When the urea liquid supply pump 8 receives the instruction work, if partial pipeline thawing abnormity occurs, the urea liquid supply pump 8 generates liquid pressure which is continuously increased, and the pressure relief valve 8b is opened at the moment, so that the pipeline is prevented from being damaged due to high pressure.

The above examples are only for illustrating the essence of the present invention, but not for limiting the present invention. Any modifications, simplifications, or other alternatives made without departing from the principles of the invention are intended to be included within the scope of the invention.

The present invention is not concerned with parts which are the same as or can be implemented using prior art techniques.

Claims

1. A novel anti-freezing SCR system comprises a urea box, a urea liquid supply pump, an SCR module body, a filter and a urea nozzle, wherein the module body comprises a liquid outlet channel and a liquid return channel, the urea liquid supply pump comprises a liquid supply nozzle, the urea nozzle comprises a liquid inlet nozzle and a liquid return nozzle,

the urea solution supply pump is arranged in the urea box, the liquid supply nozzle is connected with one end of a liquid outlet channel of the SCR module body through a liquid supply pipe, the other end of the liquid outlet channel is connected with a liquid inlet nozzle of the urea nozzle through a high-pressure pipe to form a urea solution supply flow channel, the filter is arranged on the supply flow channel,

the liquid return nozzle of the urea nozzle is connected to one end of a liquid return channel of the SCR module body through a liquid return pipe, the other end of the liquid return channel is connected with the inside of the urea box to form a urea liquid return flow channel,

the cleaning device is characterized by comprising a cleaning pump, wherein one end of the cleaning pump is connected with a liquid supply pipe, the other end of the cleaning pump is connected with a gas space on the upper part of a urea box, the cleaning pump sucks gas in the space on the upper part of the urea box, blows in a urea solution supply flow channel, returns to the urea box through a urea solution return channel and takes out residual urea solution in a pipeline.

2. A novel anti-freeze SCR system according to claim 1, wherein the urea solution supply pump comprises an expansion space and a pressure relief valve, the expansion space and the pressure relief valve being arranged near the liquid outlet nozzle, the expansion space being a space body which can deform according to the pressure.

3. The novel anti-freeze SCR system of claim 2, wherein the pressure relief valve is a pressure-dependent one-way valve.

4. The novel freeze resistant SCR system of claim 1, wherein the SCR module body comprises a filter cartridge chamber, the filter being disposed within the filter cartridge chamber.

5. A novel freeze-resistant SCR system as recited in claim 4, wherein the filter chamber includes an inlet and an outlet, the filter chamber being connected in series with the outlet passage of the SCR module body via the inlet and the outlet.

6. A novel freeze resistant SCR system as recited in claim 5, wherein said inlet is located at the bottom of the filter element chamber and said outlet is located at the top of the filter element chamber, the cross-sectional area of the outlet being substantially smaller than the cross-sectional area of the filter element chamber to facilitate fluid drainage during cleaning.