CN216130978U - A diesel national six exhaust aftertreatment system - Google Patents

Abstract

The utility model relates to a diesel national VI tail gas post-processing system. The technical proposal is that a diesel National VI after-treatment system includes a National VI post-processor and a reducing agent supply system, and an active particle filter regeneration device is arranged in the National VI after-processor. The beneficial effect of the utility model is that the active regeneration device of the particle filter is provided, which can periodically completely remove the PM particles accumulated in the National VI post-processor, improve the durability of the treatment system while meeting the emission standard, and greatly reduce the cost of pollution. The failure rate of the exhaust gas treatment system and the engine ensures the performance of the vehicle, avoids frequent maintenance, reduces maintenance costs, and at the same time the vehicle is more durable and improves economic efficiency.

Description

Diesel oil state six tail gas after-treatment system

Technical Field

The utility model relates to the field of automobile accessories, in particular to a diesel oil national six-tail gas post-treatment system.

Background

With the advance of the national six standards, in order to control the pollutant emission of heavy commercial diesel vehicles, a new standard, namely 'pollutant emission limit and measuring method of heavy commercial diesel vehicles' is issued, and compared with the previous generation standard, the new standard changes the pollutant emission limit, increases the particle number emission limit, improves the durability requirement and the like.

Because the emission limit value of the particle quantity is increased by the standard, the existing exhaust after-treatment system of the heavy diesel vehicle can not treat PM particles in the exhaust or can not meet the standard requirement, and is gradually eliminated; patent document CN212838031U discloses a linear type domestic six diesel engine exhaust purification post-treatment device, which proposes to add a oxidation catalysis unit (DOC) and a particle capture filter (DPF) in front of the existing Selective Catalytic Reduction (SCR) for capturing PM particles, but in the technical scheme, with the use of the device, PM particles are accumulated in the DPF, resulting in increase of exhaust back pressure of the engine, when the exhaust back pressure exceeds a certain value, not only the DPF will fail, but also the working condition of the engine will obviously deteriorate, seriously affecting the vehicle performance, and exceeding the emission standard, the durability requirement will not reach the standard, the maintenance or replacement of the DPF is very complicated and the cost is very high; meanwhile, the defects of large occupied space and easy crystallization of the urea catalyst at low temperature exist.

Disclosure of Invention

The utility model provides a diesel exhaust aftertreatment system capable of regenerating a particulate filter, aiming at the problems that PM particles are easy to accumulate in a DPF of the conventional diesel exhaust aftertreatment system and the durability is poor.

In order to solve the problems, the technical scheme adopted by the utility model is that the diesel oil national six tail gas post-treatment system comprises a national six post-processor and a reducing agent supply system, wherein a particle filter active regeneration device is arranged in the national six post-processor. Set up particulate filter active regeneration device, can clear away the PM granule in six postprocessors of state regularly, when satisfying the emission standard, improve processing system's durability, greatly reduced the fault rate of tail gas treatment system and engine, guarantee the vehicle performance, avoid frequent maintenance, the vehicle is more durable when reducing cost of maintenance, improves economic benefits.

Preferably, the six post-processors comprise an oxidation catalyst, a particle filter and an SCR assembly which are sequentially connected according to the flowing sequence of the tail gas, the SCR assembly comprises a selective catalytic reduction device and an ammonia gas catcher, and the active regeneration device of the particle filter is arranged at the air inlet of the oxidation catalyst. The active particulate filter regeneration device is capable of removing PM particulate from the particulate filter.

Preferably, the active regeneration device of the particulate filter is an oil injection type gas pipe, the oil injection type gas pipe is arranged at an air inlet of the oxidation type catalyst, an injection unit is arranged on the oil injection type gas pipe and communicated with a metering unit, the metering unit can take oil from a fuel oil pipeline of a vehicle, a particulate filter temperature sensor and a PM sensor are further arranged on the particulate filter, the PM sensor is used for detecting the particle accumulation amount inside the particulate filter, and the PM sensor can control the injection unit and the metering unit. When the PM sensor detects that the PM particles are excessively accumulated, controlling the injection unit to inject fuel oil into the oil injection type gas transmission pipe, burning the tail gas mixed with the fuel oil in the oxidation type catalytic converter and the particle filter to generate high temperature of 600 +/-50 ℃, and burning the accumulated PM particles until the carbon carrying amount is zero; the system can automatically detect and regularly carry out active regeneration, remove accumulated PM particles and improve the durability of the tail gas aftertreatment system.

Preferably, the injection unit is provided with an injection unit cooling bellows, and the injection unit cooling bellows is filled with engine coolant. The spraying unit is close to high temperature tail gas, through setting up cooling bellows, can cool down it, improves the durability.

Preferably, the particulate filter is further provided with a differential pressure sensor for detecting an exhaust back pressure of the particulate filter, and the differential pressure sensor is capable of controlling the injection unit and the metering unit. A plurality of parameters are measured through a plurality of sensors, the active regeneration process is controlled in a mutually matched mode, and the control effect is better.

Preferably, the reducing agent supply system comprises a urea tank and a flow guide chamber, an air outlet of the particle filter is connected with an air inlet of the flow guide chamber, an air outlet of the flow guide chamber is connected with an air inlet of the SCR assembly, an integrated water valve and a urea pump are arranged on the urea tank, a urea nozzle is arranged on the flow guide chamber, the integrated water valve is connected with a liquid absorption end of the urea pump through a pipeline, a liquid outlet end of the urea pump is connected with the urea nozzle through a pipeline, a urea nozzle cooling corrugated pipe is arranged on the urea nozzle, engine cooling liquid is communicated into the urea nozzle cooling corrugated pipe, and a liquid level sensor is further arranged on the integrated water valve and used for detecting the liquid storage amount in the urea tank. And fully mixing the oxidized and particle-removed tail gas with a urea solution in a flow guide chamber, and then carrying out catalytic reduction and ammonia gas removal.

Preferably, the connecting pipeline between the integrated water valve and the urea pump is an electric heating urea pipe, and the connecting pipeline between the urea pump and the urea nozzle is an electric heating pressure pipe. The urea solution in the pipe can be heated at low temperature, and crystallization is avoided.

Preferably, still be equipped with urea case heating inlet tube and urea case heating wet return on the integrated water valve, urea incasement portion is equipped with heating circulating water pipe, heating circulating water pipe's both ends are connected in urea case heating inlet tube and urea case heating wet return respectively, be engine coolant liquid among the heating circulating water pipe, engine coolant liquid is drawn forth from the engine by urea case heating inlet tube to get back to the engine through urea case heating wet return, switching on of urea case heating inlet tube and urea case heating wet return is controlled by the integrated water valve. The urea solution to urea incasement preheats, can avoid the urea crystallization on the one hand, and on the other hand can make the cooling of engine coolant liquid, improves the cooling effect of engine, and the heat that make full use of coolant liquid carried reduces whole car energy consumption.

Preferably, the national sixth post-processor is of a double-tank structure, the first tank comprises an oxidation type catalytic converter and a particle filter, the second tank is an SCR assembly, the first tank and the second tank are arranged in parallel, an air inlet of the oxidation type catalytic converter and an air outlet pipe are arranged in parallel, and an air outlet of the particle filter and an air inlet of the SCR assembly are arranged in parallel. The processor occupies less space.

Preferably, a temperature sensor and an upstream nitrogen-oxygen sensor before the SCR are arranged at an air inlet of the SCR assembly, a temperature sensor and a downstream nitrogen-oxygen sensor after the SCR are arranged at an air outlet of the SCR assembly, and the temperature sensor, the upstream nitrogen-oxygen sensor, the temperature sensor after the SCR and the downstream nitrogen-oxygen sensor before the SCR are matched to control the reducing agent supply system. The reaction temperature of the SCR assembly and the nitrogen and oxygen content before and after treatment are reflected more accurately through a plurality of sensors.

According to the technical scheme, the active regeneration device of the particle filter has the advantages that the active regeneration device of the particle filter is arranged, PM particles in the particle filter can be automatically and actively removed when the PM particles are accumulated to a certain amount along with high-temperature reaction, the accumulated PM particles are thoroughly removed through high-temperature combustion, the particle filter is always in the best working condition, the durability of an exhaust gas post-treatment system is greatly improved, frequent maintenance of the treatment system is avoided, and the vehicle meets the emission standard and improves the economic benefit; meanwhile, the reducing agent supply system is provided with a plurality of heating functions, urea crystallization at low temperature is avoided, the tail gas treatment effect is ensured, and heat is fully utilized by using engine cooling liquid; a plurality of sensors are arranged for monitoring and controlling together; the whole occupied space is smaller, and the installation and the use are convenient.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description will be briefly introduced, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

Fig. 1 is a first schematic structural diagram of an embodiment of the present invention.

Fig. 2 is a second structural schematic diagram of the embodiment of the utility model.

Fig. 3 is a schematic structural diagram of a chinese six post-processor according to an embodiment of the present invention.

In the figure: 1. the device comprises a national sixth postprocessor, 2, a urea box, 3, a urea pump, 4, a urea nozzle, 5, an integrated water valve, 6, a urea box heating water inlet pipe, 7, a urea box heating water return pipe, 8, an electric heating pressure pipe, 9, an electric heating urea pipe, 10, a urea nozzle cooling corrugated pipe, 11, an injection unit oil inlet pipe, 12, an injection unit, 13, a metering unit, 14, an injection unit cooling corrugated pipe, 15, an oxidation type catalyst temperature sensor, 16, a particle filter temperature sensor, 17, an SCR front temperature sensor, 18, an SCR rear temperature sensor, 19, an upstream nitrogen-oxygen sensor, 20, a differential pressure sensor, 21, a PM sensor, 22, a downstream nitrogen-oxygen sensor, 23, an oil injection type gas pipe, 24, an oxidation type catalyst, 25, a particle filter, 26, a flow guide chamber, 27, an SCR assembly and 28, an air outlet pipe.

Detailed Description

In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the present embodiment, and it is apparent that the embodiments described below are only a part of embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the scope of protection of this patent.

As shown in fig. 1-3, a diesel oil national six tail gas post-treatment system comprises a national six post-treatment device 1 and a reducing agent supply system, wherein the national six post-treatment device 1 comprises an oxidation type catalytic converter 24, a particulate filter 25 and an SCR assembly 27 which are sequentially connected according to a tail gas flowing sequence, the SCR assembly 27 comprises a selective catalytic reduction device and an ammonia gas catcher, and an air outlet pipe 28 is arranged on the SCR assembly; the six post-processors 1 in China are provided with a particle filter active regeneration device which is an oil injection type gas conveying pipe 23.

The oil injection type air delivery pipe 23 is arranged at an air inlet of the oxidation type catalytic converter 24, the oil injection type air delivery pipe 23 is provided with an injection unit 12, the injection unit 12 is connected with a metering unit 13 through an injection unit oil pipe 11, the metering unit 13 can take oil from a fuel fine filter of an engine of a vehicle, the particulate filter 25 is also provided with a particulate filter temperature sensor 16, a PM sensor 21 and a differential pressure sensor 20, the differential pressure sensor 20 is used for detecting exhaust back pressure of the particulate filter 25, the PM sensor 21 is used for detecting particle accumulation amount in the particulate filter 25, each sensor is in signal connection with an engine control unit and can control the injection unit 12 and the metering unit 13, and when triggering conditions (such as set particle accumulation amount, pressure value and time) are reached, regeneration is actively carried out; because the injection unit 12 is close to the oxidation type catalytic converter and is in a high environment temperature, the injection unit 12 is further provided with an injection unit cooling corrugated pipe 14, two ends of the injection unit cooling corrugated pipe 14 are communicated with an engine cooling liquid loop, and the injection unit cooling corrugated pipe 14 is filled with engine cooling liquid.

Besides active regeneration, the device can also carry out dynamic regeneration along with tail gas treatment, the oxidation catalyst 24 has a dynamic regeneration function while providing a catalytic oxidation function per se, the oxidation catalyst 24 is provided with an oxidation catalyst temperature sensor 15, the oxidation catalyst temperature sensor 15 is used for measuring the internal temperature of the oxidation catalyst 24, the internal temperature of the oxidation catalyst 24 in normal work is not lower than 250 ℃, and nitrogen dioxide generated by the oxidation catalyst can oxidize PM particles under the temperature condition.

The reducing agent supply system comprises a urea box 2 and a flow guide chamber 26, wherein an air outlet of a particle filter 25 is connected with an air inlet of the flow guide chamber 26, an air outlet of the flow guide chamber 26 is connected with an air inlet of an SCR assembly 27, an integrated water valve 5 and a urea pump 3 are arranged on the urea box 2, a urea nozzle 4 is arranged on the flow guide chamber 26, the integrated water valve 5 is connected with a liquid absorption end of the urea pump 3 through an electric heating urea pipe 9, and a liquid outlet end of the urea pump 3 is connected with the urea nozzle 4 through an electric heating pressure pipe 8; the integrated water valve 5 is also provided with a urea box heating water inlet pipe 6 and a urea box heating water return pipe 7, a heating circulating water pipe is arranged inside the urea box 2, two ends of the heating circulating water pipe are respectively connected with the urea box heating water inlet pipe 6 and the urea box heating water return pipe 7, engine cooling liquid is filled in the heating circulating water pipe, the engine cooling liquid is led out from an engine cooling loop through the urea box heating water inlet pipe 6 and returns to the engine cooling loop through the urea box heating water return pipe 7, the opening and closing of the urea box heating water inlet pipe 6 and the urea box heating water return pipe 7 are controlled by the integrated water valve 5, and the integrated water valve 5 is also provided with a liquid level sensor which is used for detecting the liquid storage amount in the urea box; because the urea nozzle 4 contacts high-temperature tail gas, the urea nozzle 4 is also provided with a urea nozzle cooling corrugated pipe 10, two ends of the urea nozzle cooling corrugated pipe 10 are communicated with an engine cooling liquid loop, and engine cooling liquid is introduced into the urea nozzle cooling corrugated pipe 10; the air inlet of the SCR assembly 27 is provided with an SCR front temperature sensor 17 and an upstream nitrogen-oxygen sensor 19, the air outlet of the SCR assembly 27 is provided with an SCR rear temperature sensor 18 and a downstream nitrogen-oxygen sensor 22, and the four sensors are in signal connection with an engine control unit and are matched with a reducing agent supply system and the SCR assembly in monitoring and controlling.

As shown in fig. 3, the sixth postprocessor 1 has a double-tank structure, the first tank includes an oxidation catalyst 24 and a particulate filter 25, the second tank is an SCR assembly 27, the first tank and the second tank are arranged in parallel, a diversion chamber 26 is arranged at one side of the two tanks, an air outlet of the particulate filter 25 is arranged in parallel with an air inlet of the SCR assembly 27 and is connected with one side surface of the diversion chamber 26, and an air inlet of the oxidation catalyst 24 is arranged in parallel with an air outlet pipe 28.

The working process of the system is as follows: tail gas exhausted by an engine enters a national sixth postprocessor through an oil injection type gas conveying pipe, in an oxidation type catalytic converter, carbon hydrogen, carbon monoxide and nitrogen monoxide in the tail gas are oxidized, a particle filter collects PM particles in the tail gas, meanwhile, nitrogen dioxide generated by the oxidation type catalytic converter oxidizes the PM particles in the particle filter at the temperature of not lower than 250 ℃, the PM particles are oxidized while being accumulated to achieve dynamic balance, and the tail gas enters a diversion chamber after being treated by the oxidation type catalytic converter and the particle filter;

when particle capture and dynamic regeneration are carried out, an engine control unit monitors the carbon carrying amount (reflected as the accumulation amount of PM particles) of a particle filter through a PM sensor, monitors the exhaust back pressure through a pressure difference sensor, judges whether active regeneration needs to be carried out or not according to a time condition (interval time from the last active regeneration), after the active regeneration condition is reached, a metering unit takes oil from a fuel fine filter of the engine, the oil is conveyed to an injection unit through an oil inlet pipe of the injection unit, the injection unit injects the oil into an oil injection type gas conveying pipe, the oil is mixed with tail gas and is ignited at high temperature, the combustion temperature is increased to 600 +/-50 ℃, and PM particles accumulated in the particle filter are completely combusted and oxidized until the carbon carrying amount is reduced to zero;

the operating condition information of the oxidation type catalytic converter and the particulate filter and the accumulation state of PM particles are monitored and controlled in real time through the mutual cooperation of the oxidation type catalytic converter temperature sensor, the particulate filter temperature sensor, the pressure difference sensor and the PM sensor, closed-loop control is realized, and the working state and the regeneration process are accurately controlled;

the urea pump pumps the urea aqueous solution out of the urea tank, the urea aqueous solution passes through the integrated water valve, the electric heating urea pipe, the urea pump and the electric heating pressure pipe, and is sprayed into the flow guide chamber by the urea nozzle, fully mixed with the tail gas, atomized and evaporated, enters the SCR assembly in a rotational flow mode for catalytic reduction, and the tail gas is converted into ammonia gas and other nontoxic components and is discharged by the gas outlet pipe after being absorbed by the ammonia gas; when the temperature is low, the engine control unit sends a signal to the integrated water valve, the urea box heating water inlet pipe is communicated with the urea box heating water return pipe, engine cooling liquid enters the heating circulating water pipe through the urea box heating water inlet pipe, the engine cooling liquid absorbs heat of the engine to heat, the urea solution in the urea box is heated by the heat, the engine cooling liquid is cooled, the engine cooling liquid flows back to an engine cooling system through the urea box heating water return pipe to continue cooling the engine, and meanwhile, the electric heating urea pipe and the electric heating pressure pipe are heated, so that the temperature of the urea solution is kept not to be frozen in the conveying process;

in the process of carrying out catalytic reduction and ammonia absorption on the SCR assembly, the SCR front temperature sensor, the SCR rear temperature sensor, the upstream nitrogen-oxygen sensor and the downstream nitrogen-oxygen sensor are matched to monitor the working temperature of the SCR assembly and the nitrogen-oxygen content before and after treatment in real time, and control and adjustment of the working states of the SCR assembly and the reducing agent supply system are carried out.

The active regeneration device of the particle filter has the advantages that the active regeneration device of the particle filter is arranged, PM particles in the particle filter can be removed in real time along with high-temperature reaction, the active removal can be automatically performed when the PM particles are accumulated to a certain amount, the accumulated PM particles are completely removed through high-temperature combustion, the particle filter is ensured to be in the best working condition constantly, the durability of an exhaust gas post-treatment system is greatly improved, frequent maintenance of the treatment system is avoided, and the vehicle meets the emission standard and improves the economic benefit; meanwhile, the reducing agent supply system is provided with a plurality of heating functions, urea crystallization at low temperature is avoided, the tail gas treatment effect is ensured, and the urea is heated by using the engine cooling liquid, so that the heat is fully utilized; a plurality of sensors are arranged for monitoring and controlling together; the whole occupied space is smaller, and the installation and the use are convenient.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the utility model. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. The diesel oil national six tail gas post-treatment system is characterized by comprising a national six post-treatment device (1) and a reducing agent supply system, wherein a particle filter active regeneration device is arranged in the national six post-treatment device (1);

the national six post-processor (1) comprises an oxidation type catalytic converter (24), a particle filter (25) and an SCR assembly (27) which are sequentially connected according to a tail gas flowing sequence, wherein the SCR assembly (27) comprises a selective catalytic reduction device and an ammonia gas catcher, and an active regeneration device of the particle filter is arranged at an air inlet of the oxidation type catalytic converter (24).

2. The six-phase diesel exhaust aftertreatment system according to claim 1, wherein the active particulate filter regeneration device is an oil injection type gas delivery pipe (23), an injection unit (12) is disposed on the oil injection type gas delivery pipe (23), the injection unit (12) is communicated with a metering unit (13), the metering unit (13) can take oil from a fuel pipeline of a vehicle, a particulate filter temperature sensor (16) and a PM sensor (21) are further disposed on the particulate filter (25), the PM sensor (21) is used for detecting an accumulation amount of particulates inside the particulate filter (25), and the PM sensor can control the injection unit (12) and the metering unit (13).

3. The diesel engine six-phase exhaust aftertreatment system according to claim 2, wherein the injection unit (12) is provided with an injection unit cooling bellows (14), and the injection unit cooling bellows (14) is filled with engine coolant.

4. The diesel exhaust aftertreatment system according to claim 2, wherein a differential pressure sensor (20) is further provided on the particulate filter (25), the differential pressure sensor (20) being configured to detect an exhaust gas backpressure of the particulate filter (25), the differential pressure sensor (20) being configured to control the injection unit (12) and the metering unit (13).

5. The six tail gas aftertreatment system of diesel engine according to any one of claims 1-4, wherein the reducing agent supply system comprises a urea tank (2) and a diversion chamber (26), an air outlet of the particulate filter (25) is connected with an air inlet of the diversion chamber (26), an air outlet of the diversion chamber (26) is connected with an air inlet of the SCR assembly (27), an integrated water valve (5) and a urea pump (3) are arranged on the urea tank (2), a urea nozzle (4) is arranged on the diversion chamber (26), the integrated water valve (5) is connected with a liquid suction end of the urea pump (3) through a pipeline, a liquid outlet end of the urea pump (3) is connected with the urea nozzle (4) through a pipeline, a urea nozzle cooling bellows (10) is arranged on the urea nozzle (4), and engine cooling liquid is introduced into the urea nozzle cooling bellows (10), and a liquid level sensor is further arranged on the integrated water valve (5), and the liquid level sensor is used for detecting the liquid storage amount in the urea box (2).

6. The diesel exhaust aftertreatment system according to claim 5, wherein the connecting pipeline between the integrated water valve (5) and the urea pump (3) is an electrically heated urea pipe (9), and the connecting pipeline between the urea pump (3) and the urea nozzle (4) is an electrically heated pressure pipe (8).

7. The six tail gas aftertreatment systems of diesel oil country according to claim 5, characterized in that still are equipped with urea case heating inlet tube (6) and urea case heating wet return (7) on integrated water valve (5), urea case (2) inside is equipped with heating circulating water pipe, heating circulating water pipe's both ends respectively in urea case heating inlet tube (6) with urea case heating wet return (7) are connected, be the engine coolant liquid in the heating circulating water pipe, the engine coolant liquid by urea case heating inlet tube (6) are drawn forth from the engine, and pass through urea case heating wet return (7) get back to in the engine, the switching on of urea case heating inlet tube (6) and urea case heating wet return (7) receive the control of integrated water valve (5).

8. The diesel oil country six tail gas aftertreatment system according to any one of claims 1 to 4, characterized in that the country six aftertreatment device (1) is a double-tank structure, a first tank includes the oxidation catalyst (24) and the particulate filter (25), a second tank is the SCR assembly (27), the first tank and the second tank are arranged in parallel, an air inlet of the oxidation catalyst (24) is arranged in parallel with an air outlet pipe (28) of the SCR assembly (27), and an air outlet of the particulate filter (25) is arranged in parallel with an air inlet of the SCR assembly (27).

9. The six tail gas aftertreatment system of diesel oil according to any one of claims 1-4, characterized in that a temperature sensor (17) before SCR and an upstream nitrogen-oxygen sensor (19) are arranged at an air inlet of the SCR assembly (27), a temperature sensor (18) after SCR and a downstream nitrogen-oxygen sensor (22) are arranged at an air outlet of the SCR assembly (27), and the temperature sensor (17) before SCR, the upstream nitrogen-oxygen sensor (19), the temperature sensor (18) after SCR and the downstream nitrogen-oxygen sensor (22) cooperate to control the reducing agent supply system.

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