CN112065538B - Thermal management device of diesel engine aftertreatment system - Google Patents

Thermal management device of diesel engine aftertreatment system Download PDF

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CN112065538B
CN112065538B CN202010987909.6A CN202010987909A CN112065538B CN 112065538 B CN112065538 B CN 112065538B CN 202010987909 A CN202010987909 A CN 202010987909A CN 112065538 B CN112065538 B CN 112065538B
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diesel
nozzle
gas
oil
assisted
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CN112065538A (en
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孙金辉
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F01N11/002—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
    • F01N11/005—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus the temperature or pressure being estimated, e.g. by means of a theoretical model
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/011—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more purifying devices arranged in parallel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
    • F01N3/025—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
    • F01N3/025—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust
    • F01N3/0253—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust adding fuel to exhaust gases
    • F01N3/0256—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust adding fuel to exhaust gases the fuel being ignited by electrical means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2250/00—Combinations of different methods of purification
    • F01N2250/02—Combinations of different methods of purification filtering and catalytic conversion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

A heat management device of a diesel engine exhaust treatment system comprises a gas-assisted diesel nozzle, an igniter, a diesel metering pump, an air compressor (or a compressed air source), a pumpback device and a controller, which are arranged in the diesel engine exhaust treatment system comprising at least one particulate matter filter (DPF) and a Selective Catalytic Reduction (SCR), the gas-assisted diesel oil nozzle is provided with diesel oil by an electromagnetic-driven linear electric pump and compressed air by an air compressor, the compressed air breaks the diesel oil in the nozzle to form an oil-gas mixture which is sprayed into the exhaust of an engine, the igniter ignites the oil-gas mixture to raise the exhaust temperature and realize the cleaning of the exhaust treatment system, the controller adjusts the oil quantity of the electric metering pump through a pulse-modulated (PWM) driving electric signal, compresses air flow, forms an air/fuel ratio suitable for ignition, and ensures ignition reliability. The engine exhaust treatment heat management device is good in spraying and atomizing performance, high in control precision, simple in structure and reliable in work, and can effectively control particulate matter emission and nitrogen oxide (NOx) emission of an engine.

Description

Thermal management device of diesel engine aftertreatment system
Technical Field
The invention belongs to the technical field of diesel engine exhaust aftertreatment, and particularly relates to a thermal management device of an exhaust particulate filter (DPF) and a Selective Catalytic Reduction (SCR) of a diesel engine and a control technology thereof.
Background
Diesel engines are the most important prime mover in the world today due to their high thermal efficiency and low carbon dioxide emissions, and are widely used in road and non-road vehicles, construction machinery, stationary power equipment, and the like. However, diesel engine combustion is accompanied by the production of a variety of pollutants that pollute the atmosphere and are harmful to biological health, including nitrogen oxides (NOx), Particulate Matter (PM), Hydrocarbons (HC), carbon monoxide (CO), and the like. With the increasing prominence of the human environmental problems, a plurality of countries have legislation to limit the discharge amount of environmental pollutants of various power plant products, and especially the discharge limit value of vehicles, engineering machinery, power generation equipment and the like is continuously increased.
The known main means for solving the emission problem of diesel engines is to adopt the technology of diesel exhaust treatment, including various catalytic converters and traps arranged in the exhaust pipeline, such as diesel exhaust oxidation catalysis
(DOC: Diesel Oxidation Catalyst) device, Particulate Oxidation (POC: Particulate Matter Oxidation Catalyst) device, Selective catalytic Reduction (SCR: Selective Catalyst Reduction) device, Diesel Particulate Filter (DPF: Diesel Particulate Filter), and the like.
In the Diesel Exhaust aftertreatment technology, the SCR and the DPF require special heat management devices, and the SCR needs to supply a reducing agent quantitatively, for example, Diesel Exhaust Fluid (DEF) is quantitatively injected into an Exhaust pipe, namely, 32.5% urea aqueous solution (called as AddBlue in europe) is quantitatively injected into the Exhaust pipe, and if the urea aqueous solution cannot be pyrolyzed rapidly into ammonia gas, solid byproducts are formed on the surfaces of a urea nozzle, a mixer and an SCR carrier, so that the NOx conversion rate is reduced, the engine back pressure is increased, and the engine performance is deteriorated. When the particulate matter trapped by the DPF reaches saturation or the allowable maximum value, special measures need to be taken to clean the trapped particulate matter without pollution, otherwise the trapped particulate matter blocks the DPF, which also causes the increase of the exhaust back pressure of the engine and deteriorates the performance of the engine. Thermal management devices are therefore necessary and critical.
The DPF purging techniques for diesel particulate filter traps can be divided into passive regeneration and active regeneration. Passive regeneration is the combustion of trapped particulate matter using exhaust conditions created by high load conditions that occur during normal engine operation. However, since the mode of use of the engine by the user is uncertain, this approach cannot eliminate the risk of DPF clogging, and therefore requires the deployment of active regeneration devices. Active regeneration is a special device for regenerating a DPF by generating exhaust gas at a temperature higher than a temperature at which DPF particulates can be ignited at any time according to a monitored operating state of the DPF. The temperature at which DPF particulates can ignite can also be effective to burn off urea crystallization byproducts. Therefore, designing a reasonable and effective thermal management system is the key to the success of DPF and SCR technology.
There are two main ways to actively regenerate a DPF: the main fuel injection system of the engine injects diesel oil in an injection mode or injects oil in an exhaust pipe in an expansion or exhaust stroke, and the regeneration mode of improving the exhaust temperature through DOC chemical reaction is adopted; the fuel is injected into the exhaust pipe, and the ignition combustion heats the exhaust gas.
The regeneration mode of in-cylinder oil injection is injected to the wall surface of a cylinder due to oil injection in an expansion or exhaust stroke, so that the engine oil of a crankcase is easily diluted, and the running reliability of an engine is threatened; the regeneration mode using the exhaust pipe diesel injection requires an additional diesel injection device. The regeneration mode of raising temperature by DOC chemical reaction needs calibration and engine performance calibration together, has higher calibration cost, low reliability and narrow operation range, and generates very high maintenance cost if DOC fails due to misuse of high-sulfur diesel. But is generally used because of its low cost.
The regeneration mode of injecting oil in the exhaust pipe and heating exhaust by ignition combustion effectively avoids the problems. U.S. Pat. No. 7849682B2 discloses a DPF regeneration combustion device, which is complex in structure and high in cost. Chinese patent (CN105597379B) discloses a DPF regeneration combustion apparatus, which has a complicated nozzle structure and high injection pressure, and may have a reliability problem due to the lack of the function of emptying the nozzle.
Disclosure of Invention
In order to solve the technical problems, the invention adopts the following technical scheme that the diesel engine exhaust treatment system comprises at least one particulate filter and a selective catalytic reduction device, and a gas-assisted diesel nozzle, an igniter, a back-pumping device, a controller, a metering pump and a compressed air source which are arranged on the diesel engine exhaust treatment system; the gas-assisted diesel oil nozzle comprises an oil inlet hole, an air inlet hole, a mixing chamber and an outlet hole, and diesel oil and compressed air are mixed in the mixing chamber and then sprayed out of the outlet hole; the gas-assisted diesel nozzle and the igniter are arranged in the precombustion chamber; the pumping-back device is one of a switch valve structure, an injection valve structure and a diaphragm valve structure; the gas-assisted diesel nozzle is provided with diesel oil by an electromagnetically driven linear electric pump, compressed air is provided by a compressed air source, the diesel oil is crushed and mixed by the compressed air in the gas-assisted diesel nozzle, an oil-gas mixture sprayed out of the gas-assisted diesel nozzle is ignited by an igniter, the ignited oil-gas mixture is sprayed out of the precombustion chamber and enters exhaust gas discharged by an engine, residual oxygen in the exhaust gas is utilized to be continuously combusted, the precombustion chamber (internally provided with the gas-assisted diesel nozzle and the igniter) is arranged in an inlet end cover of the DPF of the particulate filter, and the air source pressure required by the gas-assisted diesel nozzle and the outlet pressure of the diesel metering pump are determined by the internal structure of the nozzle and are not higher than 0.4 MPa; the back-pumping device is used for back-pumping the diesel oil in the nozzle to an oil supply pipeline or an oil tank after the gas-assisted diesel oil nozzle stops injecting; the controller controls the oil quantity of the electric pump and the air quantity of the air compressor through a driving electric signal of pulse modulation (PWM) to form an air fuel ratio suitable for ignition, the igniter ignites and increases the oil injection quantity to reach the gas temperature (generally more than 550C) required by DPF active regeneration and SCR crystal removal, and the metering pump, the control valve and the compressed air source are controlled to be closed to realize back pumping after the injection is stopped.
Preferably, the pumping-back device is of a switch valve structure, the switch valve is respectively connected with the metering pump, the oil tank, the gas-assisted diesel nozzle and the controller, and the compressed air source is connected with the gas-assisted diesel nozzle; in the injection state, the switch valve is closed, and diesel output by the metering pump enters the gas-assisted diesel nozzle; in the pumping-back state, the metering pump stops supplying oil, the switch valve is opened to communicate the oil tank and the gas-assisted diesel nozzle, and the pressure of the compressed air in the mixing chamber in the nozzle pushes the diesel in the nozzle back to the oil tank.
Preferably, the back-pumping device is of an injection valve structure, the injection valve is respectively connected with the metering pump and the gas-assisted diesel nozzle, the injection valve is connected with the oil tank through an electromagnetic switch valve, the electromagnetic switch valve in the injection valve is connected with the controller, and the controller is connected with the metering pump; when in the injection state, the electromagnetic switch valve closes a loop connected with the oil tank, and diesel oil from the metering pump enters the nozzle through the injection valve; when in a pumping-back state, the electromagnetic switch valve is opened and connected with a loop of the oil tank, diesel oil from the metering pump is sprayed into the injection valve and enters the oil tank through the electromagnetic switch valve, and negative pressure generated by the injection valve sucks back the diesel oil in the auxiliary gas-diesel oil nozzle.
Preferably, the pumping-back device is of a diaphragm valve structure, the diaphragm valve structure comprises a valve body, a spring and a diaphragm, the spring and the diaphragm are arranged in the valve body, a valve body cavity on one side where the spring is located is a lower cavity, the opposite side of the valve body cavity is an upper cavity, the oil tank is connected with the gas-assisted diesel nozzle through a metering pump, an electromagnetic switch valve and the lower cavity, and a compressed air source is respectively connected with the upper cavity and the gas-assisted diesel nozzle; the withdrawing means is realized by a diaphragm valve structure, the diaphragm valve structure is composed of an air cavity and a liquid cavity, the air cavity is an upper cavity of the patent claim, the liquid cavity is a lower cavity of the patent claim and is separated by an elastic diaphragm, and the liquid cavity is provided with a spring to push the diaphragm to the air cavity; in the spraying state, the liquid pressure and the spring force are greater than the gas pressure, and the diaphragm is pushed to the gas cavity; when the pumping-back state is realized, the metering pump and the electromagnetic switch valve are closed firstly, the gas pressure is greater than the spring force through the spring design, the diaphragm is pushed to the liquid cavity, the extruded liquid enters the exhaust through the gas-assisted diesel nozzle, then the air compressor is closed, the gas pressure disappears, the spring force pushes the diaphragm to the gas cavity, and the liquid in the nozzle is sucked back to the liquid cavity, so that the pumping-back function is realized. .
Preferably, the ignition device comprises a precombustion chamber, the gas-assisted diesel nozzle and the igniter are arranged in the precombustion chamber, the diameter of an outlet of the precombustion chamber is smaller than the inner diameter of a cavity of the precombustion chamber, part of spray is sprayed to the wall surface to form flow guide so that the spray whirls, local turbulence is generated at the igniter, and ignition reliability is guaranteed.
Preferably, the spray of the gas-assisted diesel nozzle is in a sector shape, and the sector is vertical to a gas flow passage in the DPF carrier, so that the oil-gas mixture is mixed with the exhaust gas of the engine in a larger space.
Preferably, the ignition control system comprises an exhaust temperature sensor which is positioned near the outlet of the precombustion chamber and is used for monitoring the exhaust temperature of the engine and the temperature of the precombustion chamber so as to ensure the reliability of ignition control.
Preferably, the device comprises a mixer which is positioned in an inlet end cover of the DPF and between an inlet and a DPF carrier, wherein the mixer consists of one or more spiral guide vanes, so that an oil-gas mixture sprayed from a precombustion chamber is further mixed with the exhaust of an engine, the uniform temperature distribution and the uniform air flow distribution are realized on the inlet surface of the DPF carrier.
Preferably, the linear electric pump comprises a driving device, a plunger assembly, a return spring, a pump end and an output end shell; the plunger assembly comprises a sleeve, a plunger, a liquid inlet valve and a liquid outlet valve; the air compressor comprises a direct current driving motor, an eccentric wheel, a connecting rod, a diaphragm, an air inlet valve and an air outlet valve; the igniter is a spark plug, the controller controls the spark plug to be electrified, and the spark plug is positioned at the spraying edge of the nozzle, so that the sprayed oil-gas mixture or steam generated by the oil-gas mixture can reach the spark plug.
Preferably, the igniter is a glow plug, the controller controls the glow plug to be electrified, and the glow plug is positioned at the edge of the spray of the nozzle, so that the sprayed oil-gas mixture or steam generated by the oil-gas mixture can reach the glow plug.
Preferably, the particulate filter is not sprayed with a catalyst or is sprayed with a catalyst which has no oxidation effect on urea and ammonia, and a selective catalytic reduction device is arranged at the downstream of the particulate filter.
Preferably, the device comprises a urea nozzle which is positioned in the DPF inlet end cover and downstream of the airflow of the precombustion chamber, and the urea spray and the diesel spray share a mixer to realize uniform distribution of ammonia in the DPF carrier inlet plane.
Preferably, the urea nozzle is an air-assisted nozzle, the spray opening of the urea nozzle is in a fan shape, the spray opening forms a linear opening on the surface of the urea nozzle, the fan-shaped inner wall of the spray opening is perpendicular to the inner flow channel of the DPF carrier, the spray sprayed by the urea nozzle is in a fan shape, and the fan shape is perpendicular to the inner flow channel of the DPF carrier, so that the urea-air mixture is mixed with the exhaust gas of the engine in a larger space.
When the diesel oil extractor works, the metering pump extracts diesel oil from the oil tank, and the diesel oil is provided to the diesel oil inlet of the nozzle through the switch valve and the oil extractor; the air compressor obtains filtered air from an air filter, and supplies the filtered air to the gas inlet of the nozzle through a single valve; the air and the diesel oil are mixed and atomized in a mixing chamber inside the nozzle, and the compressed air is sprayed into the exhaust of the engine; through the special design of the nozzle, the spray is in a fan shape and is more effectively mixed with the exhaust of the engine; the air and the diesel oil are mixed in the nozzle, so that high atomization quality can be realized under lower gas and diesel oil pressure, and the outlet pressure of the metering pump and the air compressor does not exceed 0.4 Mpa; the igniter ignites the spray, the metering pump increases the oil supply amount, the exhaust temperature is raised to exceed 550 ℃, and particles and urea crystallization byproducts accumulated in the DPF are burnt. The nozzles in other patents (us 7849682B2, chinese CN105597379B, european patent EP3517749B1, german patent DE102016221428) inject only diesel fuel, which is mixed with air outside the nozzle.
In order to avoid the blockage of the nozzle caused by the high-temperature coking of exhaust gas when diesel oil is retained in the nozzle after the injection of the nozzle is stopped, a pumpback is arranged between the metering pump and the nozzle. The back-pumping device is realized by an injection reflux valve, when in an injection state, the injection reflux valve is closed, and diesel oil output by the metering pump enters a nozzle through an injection cavity; when the diesel oil is in a pumping-back state, the injection backflow valve is opened, the diesel oil output by the metering pump returns to the oil tank through the injection cavity, negative pressure is generated in the injection cavity, and the diesel oil in the nozzle is pumped back to the oil tank.
The pumping-back device can also be realized by a diaphragm valve structure, wherein the diaphragm valve consists of an air cavity and a liquid cavity which are separated by an elastic diaphragm, and the liquid cavity is provided with a spring for pushing the diaphragm to the air cavity; the inlet of the liquid cavity is connected with the metering pump, and the outlet is connected with the liquid inlet of the nozzle; the gas cavity is connected with a gas path between the air compressor and the one-way valve; in the spraying state, the liquid pressure and the spring force are greater than the gas pressure, and the diaphragm is pushed to the gas cavity; when the pumping-back state is realized, the metering pump is closed firstly, the gas pressure is greater than the spring force through the spring design, the diaphragm is pushed to the liquid cavity, the extruded liquid enters the exhaust through the nozzle, then the air compressor is closed, the gas pressure disappears, the spring force pushes the diaphragm to the gas cavity, and the liquid in the nozzle is sucked back to the liquid cavity, so that the pumping-back function is realized.
The pumping-back device can also be realized by a switch valve structure, the switch valve is respectively connected with the metering pump, the oil tank, the gas-assisted diesel nozzle and the controller, and the compressed air source is connected with the gas-assisted diesel nozzle; in the injection state, the switch valve is closed, and diesel output by the metering pump enters the gas-assisted diesel nozzle; in the pumping-back state, the metering pump stops supplying oil, the switch valve is opened to communicate the oil tank and the gas-assisted diesel nozzle, and the pressure of the compressed air in the mixing chamber in the nozzle pushes the diesel in the nozzle back to the oil tank.
In order to avoid coking of diesel fuel in the nozzle, us 7849682B2 empties the nozzle by introducing compressed air into the nozzle diesel fuel inlet line after the injection is completed and blowing the diesel fuel in the nozzle into the exhaust. Other patents (CN105597379B, european patent EP3517749B1, german patent DE102016221428) do not mention the nozzle emptying function.
The igniter of the aftertreatment thermal management device of the present invention comprises a spark plug or glow plug controlled by the controller. The diesel auxiliary nozzle and the igniter are not directly exposed to the exhaust of the engine, but are arranged in a precombustion chamber, and the outlet of the precombustion chamber is connected with the exhaust of the engine. The size of the outlet of the precombustion chamber is smaller than that of the cavity of the precombustion chamber, so that the spark plug is not influenced by the exhaust airflow of the engine, local turbulence is generated, the optimal ignition air-fuel ratio is realized by controlling the metering pump and the air compressor, and the ignition reliability is ensured. After ignition is successful, the controller increases the oil supply amount through the metering pump according to the exhaust amount and load of the engine and the preset DPF regeneration temperature, the sprayed oil-gas mixture finds oxygen in the exhaust of the engine and continuously burns, and if enough oxygen exists in the exhaust of the engine, the flow of the compressed gas can not be increased any more. In the prior art, fuel injection, air and engine exhaust gases are mixed in a main combustion chamber (similar to the mixing chamber of the present invention), ignited, and combusted (U.S. Pat. No. 7849682B2, european patent EP3517749B1, german patent DE 102016221428). The temperature sensor is arranged at a position near the outlet of the precombustion chamber, and is used for measuring the exhaust temperature of the engine when the thermal management device does not perform jet combustion and is used for aftertreatment control; the prechamber temperature can be measured at the time of injection combustion by the heat management arrangement for ignition control.
According to the technical scheme, the Diesel Particulate Filter (DPF) is not sprayed with a catalyst or is sprayed with a catalyst without functions of urea oxidation and ammonia gas, so that a urea nozzle can be moved forward to the upstream of the DPF. Compared with a common diesel engine post-treatment system, the system cost is reduced due to the removal of a DOC device, a DPF catalyst, an air inlet throttle valve and a combined urea mixer-burner mixer; because the control requirement of DOC catalytic reaction is not needed, the air inlet throttle valve can be removed, the control and calibration of the engine are simplified, and the reliability of the engine and the post-processing system is effectively improved.
The main fuel injection system of the engine adopts a heat management mode that the diesel oil is injected in a cylinder (or the diesel oil is injected in an exhaust pipe) in an expansion or exhaust stroke to improve the exhaust temperature through DOC chemical reaction, and a urea nozzle is required to be arranged at the downstream of a DPF and the upstream of an SCR (selective catalytic reduction) because the DOC catalyst and the DPF catalyst have oxidation on urea and ammonia. The present invention does not use DOC and DPF without catalyst, so there is no problem of urea oxidation by DPF, so the urea nozzle can be placed at the upstream of DPF. The mixer is positioned between an inlet of a DPF end cover and a DPF carrier, and consists of one or more spiral flow guide vanes, so that an oil-gas mixture sprayed out of the precombustion chamber is further mixed with the exhaust of an engine, the uniform temperature distribution and the uniform airflow distribution are realized on the inlet surface of the carrier. One feature of the present invention is to place the urea nozzle also in the DPF inlet cover, downstream of the precombustor in the air stream, so that the urea spray and the diesel spray share a mixer, while achieving a uniform distribution of ammonia in the DPF carrier inlet plane. For exhaust gas flow in the end cover, the igniter and the temperature sensor are located at the upstream of the gas-assisted diesel nozzle, and the urea nozzle is located at the downstream of the gas-assisted diesel nozzle, so that corrosion of urea to the igniter is avoided.
The patents retrieved (us 7849682B2, chinese CN105597379B, european patent EP3517749B1, german patent DE102016221428) do not mention the placement of the urea nozzle upstream of the DPF.
The aftertreatment thermal management device of the present invention may further comprise: an exhaust back pressure sensor mounted on the exhaust pipe upstream of the filter or a differential pressure sensor communicating the inlet and outlet of the filter. With the sensor, the controller can determine the amount of accumulated DPF particles, determine whether to initiate a DPF regeneration sequence, detect whether regeneration is normal during regeneration, whether regeneration is effective, and whether the trapped particulate matter has been completely burned off.
Drawings
FIG. 1 is a schematic illustration of a prior art thermal management device for a diesel aftertreatment system of the present invention;
FIG. 2 is a schematic layout of a thermal management device for a diesel aftertreatment system of the present invention;
FIG. 3 is a schematic view of the overall configuration of a thermal management device for a diesel aftertreatment system of the invention;
FIG. 4 is a schematic diagram of a system integration of a thermal management device of a diesel engine aftertreatment system of the present invention.
FIG. 5 is a schematic structural diagram of a switching valve of a thermal management device of a diesel engine aftertreatment system.
FIG. 6 is a schematic structural view of an injection valve of a thermal management device of a diesel engine aftertreatment system of the invention.
FIG. 7 is a schematic diagram of a diaphragm valve structure of a thermal management device of a diesel aftertreatment system of the invention.
FIG. 8 is a schematic diagram of a pre-chamber configuration of a thermal management device for a diesel aftertreatment system of the present invention.
FIG. 9 is a schematic view of a gas-assisted diesel nozzle of a thermal management device of a diesel aftertreatment system of the invention.
The system comprises a gas-assisted diesel nozzle, an igniter, a pumpback, a controller, a particulate matter filter, a selective catalytic reducer, a diesel exhaust treatment system, a pre-combustion chamber, a metering pump, a fuel tank, a compressed air source, a S switch valve, a Y injection valve, a diaphragm valve structure, an MS. upper chamber, a MX. lower chamber, a mixer, a DPF inlet end cover, a DPF carrier, a spiral guide vane, an A-D urea nozzle, a CS exhaust temperature sensor, a T1 electromagnetic switch valve, a T2 filter, an air filter, a T3 urea supply system, a T5 pressure sensor, a T6 air inlet, a T7 diesel inlet, a T8. mixing chamber and a T9. outlet.
Detailed Description
For the purpose of enhancing the understanding of the present invention, a thermal management device for exhaust gas treatment of a diesel engine according to the present invention will be described in further detail with reference to the following examples and the accompanying drawings, which are only used for explaining the present invention and are not to be construed as limiting the scope of the present invention.
As shown in fig. 1 to 9, a thermal management device for treating exhaust gas of a diesel engine comprises a diesel engine exhaust treatment system 7 comprising at least one particulate filter 5 and a selective catalytic reduction device 6, a gas-assisted diesel nozzle 1, an igniter 2, a back-pumping device 3, a controller 4, a metering pump 9 and a compressed air source 12 which are arranged on the diesel engine exhaust treatment system 7; the gas-assisted diesel nozzle 1 and the igniter 2 are arranged in the precombustion chamber 8; the back-pumping device 3 is one of a switch valve structure, an injection valve structure and a diaphragm valve structure; the pumping-back device 3 is of a switching valve control structure, a switching valve S is respectively connected with the metering pump 9, the oil tank 10, the gas-assisted diesel nozzle 1 and the controller 4, and the compressed air source 12 is connected with the gas-assisted diesel nozzle 1; the back-pumping device 3 is of an injection valve structure, an injection valve Y is respectively connected with the metering pump 9 and the gas-assisted diesel nozzle 1, the injection valve Y is connected with the oil tank 10 through an electromagnetic switch valve, and the electromagnetic switch valve is connected with the controller 4 and the controller 4 is connected with the metering pump 9; the pumping-back device 3 is a diaphragm valve structure M, the diaphragm valve structure M comprises a valve body, a spring and a diaphragm, the spring and the diaphragm are arranged in the valve body, a lower cavity MX is formed in the valve body at one side where the spring is located, an upper cavity MS is arranged at the opposite side of the spring, an oil tank 10 is connected with the gas-assisted diesel nozzle 1 through a metering pump 9 and the lower cavity MX, and a compressed air source 12 is respectively connected with the upper cavity and the gas-assisted diesel nozzle 1; the particulate filter 5 is a particulate filter which is not sprayed with a catalyst or is sprayed with a catalyst which has no oxidation effect on urea and ammonia, and a selective catalytic reactor 6 is arranged at the downstream of the particulate filter 5; the gas-assisted diesel nozzle 1 is provided with diesel oil by an electromagnetically-driven linear electric pump, the air compressor is used for providing compressed air, the diesel oil is crushed and mixed by the compressed air in the gas-assisted diesel nozzle 1, an oil-gas mixture sprayed by the gas-assisted diesel nozzle 1 is ignited by the igniter 2, the gas-assisted diesel nozzle 1 and the igniter 2 are installed in the precombustion chamber 8, the precombustion chamber 8 is internally installed in a DPF inlet end cover 51 of the particulate filter 5, the air source pressure and the diesel metering pump outlet pressure required by the gas-assisted diesel nozzle 1 are determined by the internal structure of the nozzle and are not higher than 0.4MPa, the pumpout 3 pumps the diesel oil in the nozzle back into an oil supply pipeline or an oil tank after the gas-assisted diesel nozzle 1 stops spraying, the controller 4 controls the oil mass of the electric pump and the air quantity of the air compressor through a driving electric signal of Pulse Width Modulation (PWM) to form an air fuel ratio suitable for ignition, the metering pump 9, the control valve and the compressed air source 12 are closed to realize back pumping after the injection is stopped; the gas-assisted diesel nozzle 1 comprises an oil inlet, an air inlet, a mixing chamber and an outlet, wherein diesel and compressed air form mixed gas in the mixing chamber and are sprayed into the exhaust of an engine by the pressure of the compressed air; the mixer H is positioned between a DPF inlet end cover 51 and a DPF carrier 52 and consists of one or more spiral guide vanes 22, so that an oil-gas mixture sprayed from a precombustion chamber is further mixed with engine exhaust, the uniform temperature distribution and the uniform airflow distribution are realized on the inlet surface of the carrier; the device comprises urea nozzles A-D, wherein the urea nozzles A-D are positioned in an inlet end cover 51 of the DPF and downstream of airflow of a precombustion chamber 8, and urea spray and diesel spray share one mixer H to realize uniform distribution of ammonia in an inlet plane of a DPF carrier 52; the device comprises an exhaust temperature sensor CS which is positioned at the outlet of the precombustion chamber 8 and is used for monitoring the exhaust temperature of the engine and the temperature of the precombustion chamber, so that the ignition reliability control is ensured.
When in work, the metering pump 9 pumps diesel oil from the oil tank 10, and the pumping-back device 3 provides the diesel oil inlet T7 of the gas-assisted diesel oil nozzle 1 through the switch valve T1; the compressed air source 12 takes filtered air from an air filter T3 and supplies it to the air inlet T6 of the air-assisted diesel nozzle 1 via a one-way valve; the air and the diesel oil are mixed and atomized in the gas-assisted diesel oil nozzle 1, and the compressed air is sprayed into a diesel engine exhaust treatment system 7; the gas-assisted diesel nozzle 1 sprays to form a sector, so that the sprayed combustion mixed gas is more effectively mixed with the engine exhaust; the air and the diesel oil are mixed in the nozzle, so that high atomization quality can be realized under low gas and diesel oil pressure, and the jun between the outlet pressure of the metering pump 9 and the outlet pressure of the air compressor is not more than 0.4 MPa. The igniter 2 ignites the spray to raise the exhaust temperature to over 550 ℃, thereby burning off the particles and urea crystallization by-products accumulated in the DPF. The gas pilot nozzle 1 is shown in fig. 9 below.
In order to avoid the blockage of the nozzle caused by exhaust high-temperature coking when diesel oil is retained in the nozzle after the gas-assisted diesel oil nozzle 1 stops injecting, a pumping-back device 3 is arranged between a metering pump 9 and the gas-assisted diesel oil nozzle 1. The back-pumping device 3 is realized by an injection valve Y, when in an injection state, the injection valve Y is closed, and diesel oil output by the metering pump 9 enters the gas-assisted diesel oil nozzle 1 through the injection cavity; in a back-pumping state, the injection valve Y is opened, the diesel oil output by the metering pump 9 returns to the oil tank 10 through the injection cavity, negative pressure is generated in the injection cavity, and the diesel oil in the gas-assisted diesel oil nozzle 1 is pumped back to the oil tank 10.
The pumping-back device is realized by a control structure of a switch valve S, the switch valve S is respectively connected with a metering pump 9, an oil tank 10, a gas-assisted diesel nozzle 1 and a controller 4, and a compressed air source 12 is connected with the gas-assisted diesel nozzle 1; in the injection state, the switch valve S is in the closed state, and diesel oil output by the metering pump 9 enters the gas-assisted diesel oil nozzle 1; in the pumping-back state, the metering pump 9 stops supplying oil, the switch valve S is opened to communicate the oil tank 10 and the gas-assisted diesel nozzle 1, and the pressure of the compressed air source 12 in the mixing chamber in the nozzle pushes the diesel oil in the nozzle back to the oil tank 10.
The pumping-back means 3 can also be realized by a diaphragm valve structure M consisting of a gas chamber MS and a liquid chamber MX separated by an elastic diaphragm, the liquid chamber MX being provided with a spring to push the diaphragm towards the gas chamber MS; one end of the liquid cavity is connected with the metering pump 9, and the other end is connected with a liquid inlet of the gas-assisted diesel nozzle 1; the gas cavity MS is connected to a gas path between the compressed air source 12 and the one-way valve; in the spraying state, the liquid pressure and the spring force are greater than the gas pressure, and the diaphragm is pushed to the gas cavity MS; in a pumping-back state, the metering pump 9 is closed, the gas pressure is greater than the spring force through the spring design, the diaphragm is pushed to the liquid cavity MX, the extruded liquid enters exhaust gas through the gas-assisted diesel nozzle 1, then the compressed air source 12 is closed, the gas pressure disappears, the spring force pushes the diaphragm to the gas cavity MS, and the liquid in the nozzle is sucked back to the liquid cavity MX, so that the pumping-back function is realized; it should be noted that the gas chamber MS is equivalent to the upper chamber described above, and the liquid chamber MX is equivalent to the lower chamber described above.
The igniter of the aftertreatment thermal management device of the present invention comprises a spark plug or glow plug controlled by the controller 4. The diesel auxiliary nozzle 1 and the igniter are not directly exposed to the engine exhaust gas, but are arranged in a precombustion chamber 8, and the outlet of the precombustion chamber 8 is connected with the engine exhaust gas. The size of the outlet of the precombustion chamber 8 is smaller than that of the cavity of the precombustion chamber, so that the spark plug is not influenced by the exhaust airflow of the engine, local turbulence is generated, the air-fuel ratio for realizing optimal ignition is controlled by the metering pump 9 and the compressed air source 12, and the ignition reliability is ensured. After ignition is successful, the controller 4 increases the fuel supply by the metering pump 9 according to the engine exhaust gas amount, load and predetermined DPF regeneration temperature (e.g. 600C), and the injected diesel oil finds oxygen in the engine exhaust gas outside the pre-combustion chamber 8 and continues to burn, at which time the compressed gas flow rate may not increase any more. A temperature sensor is arranged at the outlet accessory of the precombustion chamber 8, and the exhaust temperature of the engine is measured when the thermal management device does not spray oil for combustion, so that the exhaust temperature is used for aftertreatment control; the prechamber temperature can be measured during the fuel injection combustion of the heat management device for ignition control.
The thermal management device of the diesel engine after-treatment system in the prior art is shown in figure 1, and the technical scheme of the invention comprises that a Diesel Particulate Filter (DPF) is not sprayed with a catalyst or is sprayed with a catalyst with the functions of non-oxidized urea and ammonia gas, so that urea nozzles A-D can be moved forward to the upstream of the DPF. Compared with a common diesel engine post-treatment system, the system cost is reduced due to the removal of the DOC device, the DPF catalyst, the air inlet throttle valve and the combination of the urea mixer and the combustor mixer; because the control requirement of DOC catalytic reaction is not needed, an air inlet throttle valve of the engine can be removed, the control and calibration of the engine are simplified, and the reliability of the engine and an aftertreatment system is effectively improved.
The main fuel injection system of the engine is adopted to inject diesel oil in a cylinder (or inject oil in an exhaust pipe) in an expansion or exhaust stroke, and a heat management mode of improving exhaust temperature through DOC chemical reaction is adopted. The present invention does not use DOC and DPF without catalyst, so there is no problem of urea oxidation by DPF, so urea nozzles a-D can be placed upstream of DPF. The mixer H is positioned between an inlet of a DPF end cover and a DPF carrier, and consists of one or more spiral flow guide vanes, so that an oil-gas mixture sprayed out of the precombustion chamber 8 is further mixed with engine exhaust, the uniform temperature distribution and the uniform airflow distribution are realized on the inlet surface of the carrier. One feature of the present invention is that urea nozzles a-D are placed in the DPF inlet closure downstream of the gas stream in the pre-combustion chamber 8, so that the urea sprays a-D share a mixer H (as shown in fig. 3) with the gas-assisted diesel nozzle 1, while achieving a uniform distribution of ammonia in the DPF carrier inlet plane. With respect to the exhaust gas flow in the end cap, the igniter 2 and the temperature sensor are located upstream of the gas-assisted diesel nozzle 1, and the urea nozzles a-D are located downstream of the gas-assisted nozzles, so as to avoid corrosion of the igniter 2 by urea.
The DPF regeneration device includes an exhaust back pressure sensor installed on the exhaust pipe upstream of the filter T2 or a differential pressure sensor communicating with the inlet and outlet of the filter to measure the amount of particulate accumulation in the DPF.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein. The invention takes a diesel engine as an example, and is also applicable to an exhaust gas treatment system which comprises a DPF and an SCR and is used for a natural gas engine and a gasoline engine.

Claims (10)

1. A diesel exhaust treatment thermal management device, comprising: the diesel engine exhaust gas treatment system (7) comprises at least one particulate filter (5) and a selective catalytic reduction device (6), and an air-assisted diesel nozzle (1), an igniter (2), a back-pumping device (3), a controller (4), a metering pump (9) and a compressed air source (12) which are arranged on the diesel engine exhaust gas treatment system (7);
the gas-assisted diesel nozzle (1) comprises an oil inlet hole (T7), an air inlet hole (T6), a mixing chamber (T8) and an outlet hole (T9), wherein diesel oil and compressed air are mixed in the mixing chamber (T8) and then are sprayed out from the outlet hole (T9);
the gas-assisted diesel nozzle (1) and the igniter (2) are arranged in the precombustion chamber (8); the diameter of the outlet of the precombustion chamber is smaller than the inner diameter of the cavity of the precombustion chamber, so that part of spray is sprayed on the wall surface to form diversion so as to lead the spray to swirl, and local turbulence is generated at the igniter, so that the ignition reliability is ensured;
the pumping-back device (3) is one of a switch valve structure, an injection valve structure and a diaphragm valve structure, the pumping-back device (3) is respectively connected with the controller (4), the metering pump (9), the oil tank (10) and the gas-assisted diesel nozzle (1), and the gas-assisted diesel nozzle (1) is connected with the compressed air source (12).
2. The diesel exhaust treatment thermal management device of claim 1, wherein: the pumping-back device (3) is of a switch valve structure, the switch valve (S) is respectively connected with the metering pump (9), the oil tank (10), the gas-assisted diesel nozzle (1) and the controller (4), and the compressed air source (12) is connected with the gas-assisted diesel nozzle (1).
3. The diesel exhaust treatment thermal management device of claim 1, wherein: the back-pumping device (3) is of an injection valve structure, an injection valve (Y) is respectively connected with the metering pump (9) and the gas-assisted diesel nozzle (1), the injection valve (Y) is connected with the oil tank (10) through an electromagnetic valve switch (T1), the electromagnetic valve switch in the injection valve (Y) is connected with the controller (4), and the controller (4) is connected with the metering pump (9).
4. The diesel exhaust treatment thermal management device of claim 1, wherein: pumpback device (3) diaphragm valve structure (M), diaphragm valve structure (M) include the valve body, establish spring and diaphragm in the valve body, and the valve body chamber of one side at spring place is lower cavity room (MX), and one side is last cavity (MS) relative to it, and oil tank (10) are connected with gas-assisted diesel nozzle (1) through measuring pump (9), lower cavity room (MX), and compressed air source (12) are connected respectively with last cavity, gas-assisted diesel nozzle (1).
5. The diesel exhaust treatment thermal management device of claim 1, wherein: the particulate filter (5) is a particulate filter which is not sprayed with a catalyst or is sprayed with a catalyst which has no oxidation effect on urea and ammonia, and a selective catalytic reduction device (6) is arranged at the downstream of the particulate filter (5).
6. The diesel exhaust treatment thermal management device of claim 1, wherein: the spray from the gas-assisted diesel nozzle is in a sector shape, and the sector is vertical to the inner flow channel of the DPF carrier, so that the oil-gas mixture is mixed with the engine exhaust in a larger space.
7. The diesel exhaust treatment thermal management device of claim 1, wherein: the mixer (H) is positioned between a DPF inlet end cover (51) and a DPF carrier (52), and consists of one or more spiral guide vanes (22), so that an oil-gas mixture sprayed from a precombustion chamber is further mixed with engine exhaust, the uniform temperature distribution and the uniform air flow distribution are realized on the inlet surface of the carrier.
8. The diesel exhaust treatment thermal management device of claim 1 or 5, wherein: the device comprises a urea nozzle which is positioned in a DPF inlet end cover (51) and at the downstream of the airflow of a pre-combustion chamber (8), and urea spray and diesel spray share a mixer (H) to realize the uniform distribution of ammonia in the inlet plane of a DPF carrier (52).
9. The diesel exhaust treatment thermal management device of claim 1, wherein: the ignition control system comprises an exhaust temperature sensor (CS), wherein the exhaust temperature sensor (CS) is positioned at an outlet of the precombustion chamber (8), and is used for monitoring the exhaust temperature of an engine and the temperature of the precombustion chamber, so that the ignition control reliability is ensured.
10. The diesel exhaust treatment thermal management device of claim 8, wherein: the urea nozzle is an air auxiliary nozzle, the jet orifice of the urea nozzle is in a fan shape, a linear opening is formed in the surface of the urea nozzle by the jet orifice, the fan-shaped inner wall of the jet orifice is perpendicular to the inner flow channel of the DPF carrier, the spray sprayed by the urea nozzle is in a fan shape, and the fan shape is perpendicular to the inner flow channel of the DPF carrier, so that the urea-air mixture is mixed with the exhaust gas of the engine in a larger space.
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