KR20120100633A - Fuel injection device and exhaust aftertreatment apparatus including the same - Google Patents

Abstract

PURPOSE: A fuel jetting apparatus and an exhaust gas post-processing system equipped with the same are provided to activate catalysts with increasing the purification efficiency. CONSTITUTION: A fuel jetting apparatus(100) comprises a housing(200), a fuel supply unit(300), an air supply unit(400), a heater unit(500), and a spraying nozzle(600). The fuel supply unit injects sprays liquid fuel to the housing by mixing the fuel with air The fuel supply unit comprise a fuel nozzle(310) and a mixing nozzle(320). The mixing nozzle is extended from the fuel nozzle, and mixes the fuel with the air. The air supply unit is connected to the fuel supply unit. The heater unit generates a mixture of vaporized gas by heating the fuel and air sprayed from the fuel supply unit. The spraying nozzle is connected to the housing to spray the mixture of gas to an exhaust pipe.

Description

Fuel Injection Device and Exhaust Aftertreatment Apparatus Including The Same}

The present invention relates to a fuel injection device, and more particularly, to a fuel injection device for injecting fuel into an exhaust pipe for exhaust gas aftertreatment of an automobile, and an exhaust gas aftertreatment system having the same.

In general, the exhaust gas of an automobile refers to the exhaust gas from the engine, in which the mixer combusted is released into the atmosphere through the exhaust pipe. Exhaust gas includes air pollutants, which include gaseous substances such as CO, CO ₂ , NOx, HC, and particulate matter (PM, Particulate Matter) such as Soot, SOF, Soluble Organic Fraction, and Sulfate.

Gasoline engines can remove most of the gaseous substances such as CO, HC, and NOx (called three-way) by using three-way catalysts using platinum, palladium, and rhodium as catalysts, and contamination by particulate matter is minimal.

However, diesel engines have a problem in that the amount of NOx and particulate matter is increased due to the use of excess air because it is difficult to form a uniform mixer. In particular, as the demand for diesel vehicles has soared, air pollution by vehicles has caused problems in various fields. At present, the air pollution in our country has reached a very serious level. Accordingly, the exhaust gas regulation of automobiles is being tightened.

Recently, gasoline vehicles equipped with a gasoline direct injection (GDI) engine, which directly injects fuel such as a diesel vehicle and enables combustion at a thin air-fuel ratio, have been released. However, the GDI engine vehicle has the advantage of high fuel economy, but there is a problem that the generation of NOx increases.

Accordingly, the vehicle is provided with a particulate matter removal filter for separately collecting and removing particulate matter in the exhaust gas, and an exhaust gas aftertreatment system such as a NOx reduction catalyst for nitrogen oxide removal. Exhaust gas after-treatment systems include particulate matter removal filters such as DPF (Disel Particulate Filter) and NOx reduction catalysts such as Selective Catalytic Reduciton (SCR) and Lean NOx Trap (LNT).

DPF, a representative type of particulate removal filter, collects particulate matter generated in exhaust gas of diesel engine in catalyst filter with porous wall installed between exhaust pipes without discharging it out of the vehicle. It is a device to remove the collected particulate matter by raising the temperature. When the particulate matter collected in the catalyst filter is collected for a predetermined amount or more, the collected particulate matter is burned and reused without replacing the filter so that the ventilation of the exhaust gas is not lowered. The regeneration of the filter in the DPF consists of raising the temperature of the exhaust gas through post-fuel injection to raise the inside of the particulate filter above the ignition temperature, and to burn the soot accumulated at the target temperature reached.

The NOx reduction catalyst is an exhaust gas purification catalyst mainly for purifying NOx in the exhaust gas. The NOx passing through the exhaust pipe is occluded through a catalyst, and then the NOx stored in the regeneration process is reduced to harmless N ₂ for purification. In particular, the technology using LNT uses a hydrocarbon (HC) -based fuel as a reducing agent to reduce NOx. When driving in an area where the air-fuel ratio of the engine is lean, the NOx is stored in the LNT catalyst. When NOx is saturated, NOx is reduced to N ₂ by using fuel as a reducing agent.

As such, technologies using particulate matter removal filters such as DPF and NOx reduction catalysts such as LNT, which use fuel as a reducing agent, are used in the hydrocarbon (HC) series such as gas oil or gasoline (GDI) to oxidize particulate matter or reduce NOx. Has a system for injecting liquid fuel into the exhaust pipe.

The present invention is to solve the various problems including the above problems as a fuel injection device that can improve the exhaust gas purification efficiency by increasing the degree of atomization of the liquid fuel injected into the exhaust pipe even under the low temperature of the exhaust gas And an exhaust gas aftertreatment system having the same. However, these problems are exemplary and do not limit the scope of the present invention.

According to an aspect of the invention, the housing; A fuel supply unit which receives a liquid fuel and mixes it with air to inject it into the housing; An air supply unit communicating with the fuel supply unit to mix air with the liquid fuel; A heater unit for heating the fuel and air injected from the fuel supply unit to form a vaporized mixer; And a spray nozzle coupled to the housing such that the mixer is sprayed into the exhaust pipe.

The fuel supply unit includes a fuel nozzle injecting the fuel in the liquid state; And a mixing nozzle extending from the fuel nozzle and mixing the fuel and air.

The air supply unit may include an air nozzle communicating with the mixing nozzle to supply air to the mixing nozzle.

The heater unit may include a heating rod mounted inside the housing to be connected to the spray nozzle.

The heating rod has a spiral groove helically recessed in the outer peripheral surface along the longitudinal direction, the mixing nozzle of the fuel supply portion may be adjacent to the spiral groove.

The housing may include a first housing in which the fuel supply unit and the air supply unit are mounted, and a second housing connected to the spray nozzle while communicating with the first housing.

The housing has a through hole for communicating the first housing and the second housing, and the heating rod may be mounted to the first housing and the second housing through the through hole.

A cross section of the through hole and the heating rod may have a circular shape, and the heating rod may be disposed in a central region of the through hole so that the heating rod and the through hole are spaced apart from each other to form a flow path.

It may further include a temperature sensor for sensing the temperature of the heater unit, a pressure sensor for detecting the pressure of the fuel supply unit.

The air supply unit may be connected to a compressor mounted on the vehicle to compress and supply the atmosphere.

The fuel supply unit may be connected to a fuel tank or a separate fuel tank for supplying fuel to the engine.

On the other hand, according to another aspect of the present invention, there is provided an exhaust gas aftertreatment apparatus including at least one of the above fuel injection devices.

According to the fuel injection device and the exhaust gas after-treatment system having the same according to the embodiment of the present invention made as described above, the atomization occurs smoothly even in a low exhaust gas temperature and the spray area is expanded, so that the activity of the catalyst and the exhaust gas The purification efficiency of can be improved together.

The effects of the present invention are not limited to those mentioned above, and other effects, which are not mentioned above, will be clearly understood by those skilled in the art from the following description.

1 is a schematic diagram of an exhaust gas aftertreatment system of the present invention.
FIG. 2 is a perspective view of an embodiment of the fuel injection device shown in FIG. 1.
3 is a cross-sectional view of the housing shown in FIG. 2.
4 is an enlarged view illustrating main parts of the heating rod illustrated in FIG. 2.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, Is provided to fully inform the user. Also, for convenience of explanation, the components may be exaggerated or reduced in size.

In the following examples, the term mixer is used to include a substance in a vaporized state while a mixture of air and liquid fuel is heated.

1 is a schematic configuration diagram of an exhaust gas aftertreatment system of the present invention, FIG. 2 is a perspective view of an embodiment of the fuel injection device illustrated in FIG. 1, and FIG. 3 is a view of the housing illustrated in FIG. 2. FIG. 4 is an enlarged view illustrating main parts of the heating rod shown in FIG. 2.

As illustrated in FIG. 1, the exhaust gas aftertreatment system of the present embodiment includes a fuel tank 10 in which fuel is stored, and a fuel injection device 100 for injecting fuel stored in the fuel tank 10 into the exhaust pipe 50. It is made, including. The fuel tank 10 and the fuel injection device 100 may be connected by a fuel supply line. The fuel stored in the fuel tank 10 may flow into the fuel injection device 100 while moving in the left arrow direction along the fuel supply line, and some may flow back into the fuel tank 10 as in the right arrow direction. The fuel supply line may be equipped with a regulator 20 as a pressure regulator for maintaining a constant charging pressure of the fuel, the amount of fuel supplied to the fuel injection device 100 can be adjusted appropriately.

The fuel tank 10 may be installed in the vehicle to supply fuel to the engine and may be provided separately for the exhaust gas aftertreatment system. The fuel tank 10 may store gasoline or diesel in a liquid state. For example, diesel fuel is stored in diesel fuel tanks that use hydrocarbon (HC) -based fuels as reducing agents, such as DPF (Disel Particulate Filter) and LNT (Lean NOx Trap), and GDI (Gasoline Direct Injection) engine is installed. Gasoline may be stored in the fuel tank of the gasoline vehicle.

The fuel injection device 100 may receive fuel from the fuel tank 10 through a fuel supply line and inject fuel into the exhaust pipe 50. Fuel injected into the exhaust pipe 50 through the fuel injection device 100 is atomized, and HC contained in the atomized fuel is used as a reducing agent for reducing exhaust gas.

More specifically, as shown in FIG. 2, the fuel injection device 100 includes a housing 200 in which the mixer is accommodated, a spray nozzle 600 for atomizing the atomizer by injecting the mixer into the exhaust pipe 50, and a housing ( A heater unit 500 for heating 200, a fuel supply unit 300 for supplying fuel to the housing 200, and an air supply unit 400 for supplying air to the fuel supply unit 300 may be provided.

The housing 200 may have an inner space in which the mixer is accommodated, and the mixer 200 is supplied to the spray nozzle 600. The housing 200 may have a variety of shapes, the first housing 210 and the first housing 210 in which the fuel supply unit 300 and the air supply unit 400, which will be described later, are provided on the upper portion as in the present embodiment, and communicate with the first housing 210. The second housing 220 may be provided below the first housing 210 so as to be connected to the spray nozzle 600.

The first housing 210 may be formed in a rectangular parallelepiped shape with a bottom surface 211 having a rectangular shape and an empty inside. The fuel supply unit 300 may be mounted at one corner of the first housing 210, and the air supply unit 400 may be mounted at one side of the first housing 210. Of course, the air supply unit 400 may be mounted on one side edge area of the first housing 210, and the air supply unit 400 may be mounted on one side of the first housing 210.

The second housing 220 may be formed in a hollow pipe shape having an inner space having a circular cross section. A circular through hole 215 corresponding to the cross-sectional shape of the second housing 220 is formed under the first housing 210, that is, the bottom surface 211, and the second housing 220 extends from the through hole 215. It may have a form. That is, the first housing 210 and the second housing 220 communicate with each other by the through hole 215, and the through hole 215 may serve as a flow path through which the mixer flows.

Spray nozzle 600 is coupled to the housing 200, the atomizer is sprayed into the exhaust pipe 50 to be atomized. If the atomization of the fuel injected in the exhaust pipe 50 is made well, it can be quickly mixed with the exhaust gas, thereby improving the purification efficiency of the exhaust gas while preventing the performance and fuel efficiency of the catalyst. In this aspect, the spray nozzle 600 increases the atomization degree in the exhaust pipe 50 by injecting two fluids, a gaseous fuel and a liquid fuel having a small and evenly decomposed liquid size. do. Spray nozzle 600 may be mounted to the exhaust pipe 50 through a separate fixing device as shown in FIG.

On the other hand, the housing 200 may be heated by the heater unit 500. The heater unit 500 forms a temperature around the housing 200 at a temperature in which it is easy to vaporize, so that the fuel in the liquid state is quickly vaporized. That is, the heater unit 500 promotes vaporization of the liquid fuel injected into the housing 200 through the fuel supply unit 300 by heating the housing 200. Therefore, the gaseous fuel vaporized and the liquid fuel not vaporized may be mixed in the housing 200.

The heater unit 500 may heat the housing 200 from the outside, but preferably includes a heating rod 510 mounted inside the housing 200 to be connected to the spray nozzle 600. Efficient heat transfer can be achieved internally.

The heating rod 510 is inserted into the through hole 215 and is mounted to both the first housing 210 and the second housing 220. That is, one end of the heating rod 510 is coupled to the first housing 210 and the other end is coupled to the spray nozzle 600 to form the housing 200 and the spray nozzle 600 at a temperature suitable for vaporization.

The heating rod 510 may be formed in a bar shape having a polygonal cross section, such as a circle or a triangle. For example, as described above, since the cross section of the through hole 215 formed in the housing 200 has a circular shape, the heating rod 510 inserted into the through hole 215 may have a rod shape having a circular cross section. The heating rod 510 may be spaced apart from the through hole 215 while the cross section is made smaller than the size of the through hole 215. The heating rod 510 is a central region of the through hole 215 so that the gaseous fuel and the liquid fuel can be smoothly moved to the spray nozzle 600 through the spaced space between the through hole 215 and the heating rod 510. Can be placed in.

On the other hand, the heating rod 510 may have a spiral groove 520 recessed in a spiral shape on the outer peripheral surface along the longitudinal direction. As shown in FIG. 4, the spiral grooves 520 may have a shape recessed in a streamlined shape from the surface of the heating rod 510, and may be arranged in a spiral shape along a length direction to form a flow path. The spiral groove 520 may increase the surface area of the heating rod 510 to increase the heat transfer area to the housing 200. Accordingly, the heating rod 510 may more quickly and efficiently promote vaporization of the mixture of the liquid fuel and air to generate a mixer having a reduced droplet size and send the spray nozzle 600 to the spray nozzle 600.

Unlike the foregoing, the spiral groove 520 may be recessed in the surface of the heating rod 510 in a shape other than streamlined as needed, or may have a shape protruding from the surface of the heating rod 510 to increase the heat transfer area. There will be. The helical groove 520 is injected into the liquid fuel mixed with air from the fuel supply unit 300, which will be described later, the helical groove 520 is guided so that the mixture of the fuel in the liquid state mixed with air is heat evaporated Can play a role.

The spiral groove 520 may be formed in the entire longitudinal direction of the heating rod 510 but may be formed from a position corresponding to the injection position of the fuel supply unit 300 as shown in FIG. 2.

The fuel supply unit 300 may receive the liquid fuel from the fuel tank 10 and mix the mixture with air to inject the inside of the housing 200. In detail, the fuel supply unit 300 may include a fuel nozzle 310 and a mixing nozzle 320 extending with the fuel nozzle 310.

The fuel nozzle 310 is injected in a liquid state, and may be disposed above the first housing 210 to be inclined at an angle in the vertical direction. One end of the mixing nozzle 320 may extend from the fuel nozzle 310 and the other end thereof may be disposed adjacent to the spiral groove 520 of the heating rod 510. In this case, since the lower end of the fuel nozzle 310 communicates with the air nozzle 410 of the air supply unit 400 to be described later, air and fuel may be primarily mixed in the mixing nozzle 320. The mixing nozzle 320 injects fuel mixed with air into the spiral groove 520 of the heating rod 510.

As such, the fuel supply unit 300 primarily mixes fuel and air in a liquid state and injects the heating rod 510.

The air supply unit 400 may use the air as it is, but may be connected to a compressor mounted on the vehicle to supply high pressure air to the fuel supply unit 300. As described above, the air supply unit 400 may include an air nozzle 410 communicating with the fuel nozzle 310 of the fuel supply unit 300. Accordingly, the fuel nozzle 310, the air nozzle 410, and the mixing nozzle 320 form a Y-shaped flow path, and the air supply unit 400 mixes air with liquid fuel injected from the fuel nozzle 310. The mixer with the reduced droplet size is sprayed into the mixing nozzle 320.

On the other hand, the fuel injection device 100 may include a temperature sensor 40 for detecting the temperature of the heater unit 500, and a pressure sensor 30 for detecting the pressure of the fuel supply unit 300.

When the heating rod 510, which promotes vaporization of the fuel in the liquid state and reduces the size of the liquid droplet, is heated to an excessive temperature as in this embodiment, deposits of fuel may occur on the surface of the heating rod 510. The temperature sensor 40 may measure the temperature of the heating rod 510, for example, to control the temperature of the heating rod 510 to maintain 180 ~ 260 ℃ when gasoline fuel is used.

In addition, the air supply unit 400 may inject air for a predetermined period after the fuel injection is finished to discharge the remaining fuel remaining in the mixing nozzle 320 and the heating rod 510 of the fuel supply unit 300 to prevent deposition. .

The pressure sensor 30 may be used for monitoring the fuel supply unit 300 to inject a quantity of fuel, or may be used to measure the air pressure of the air supply unit 400 or the pressure of the spray nozzle 600. In FIG. 1, reference numeral 60 denotes a cooling device for maintaining an appropriate temperature when the exhaust gas temperature is high.

As such, the liquid fuel is injected into the housing 200 through the fuel supply unit 300 in a state in which the droplet size is primarily reduced while being mixed with air by the air supply unit 400. In addition, since the mixer in the state in which evaporation is further promoted by the heating rod 510 located inside the housing 200 is supplied to the spray nozzle 600, the liquid state and the gas of the droplets are further finely and evenly injected. Since two fluids of the fuel in the state are injected into the exhaust pipe 50, the degree of atomization is remarkably improved, whereby the spray area can be expanded.

Therefore, according to the fuel injection device and the exhaust gas after-treatment apparatus having the same according to the embodiment of the present invention, since atomization occurs smoothly even under low exhaust gas temperature, the activity of the catalyst and the purification efficiency of the exhaust gas can be improved together. .

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: fuel injection device 200: housing
210: first housing 220: second housing
300: fuel supply unit 310: fuel nozzle
320: mixed nozzle 400: air supply
410: air nozzle 500: heater
510: heating rod 520: spiral groove
600: spray nozzle

Claims (12)

housing;
A fuel supply unit which receives a liquid fuel and mixes it with air to inject it into the housing;
An air supply unit communicating with the fuel supply unit to mix air with the liquid fuel;
A heater unit for heating the fuel and air injected from the fuel supply unit to form a vaporized mixer; And
A spray nozzle coupled to the housing such that the mixer is sprayed into the exhaust pipe;
Fuel injection device comprising a. The method of claim 1,
The fuel supply unit includes a fuel nozzle injecting the fuel in the liquid state; And a mixing nozzle extending from the fuel nozzle and mixing the fuel and air. The method of claim 2,
And the air supply unit includes an air nozzle communicating with the mixing nozzle to supply air to the mixing nozzle. The method of claim 1,
The heater unit comprises a heating rod mounted inside the housing to be connected to the spray nozzle, fuel injection device. 4. The fuel injection device according to claim 3, wherein the heating rod has a spiral groove helically recessed on an outer circumferential surface along a longitudinal direction, and the mixing nozzle of the fuel supply portion is adjacent to the spiral groove. The method of claim 1,
The housing includes a first housing in which the fuel supply unit and the air supply unit are mounted, and a second housing connected to the spray nozzle while communicating with the first housing. The method of claim 6,
The housing has a through hole for communicating the first housing and the second housing, the heating rod is mounted to the first housing and the second housing through the through hole, the fuel injection device. The method of claim 7, wherein
Cross section of the through hole and the heating rod is made of a circular, the heating rod and the heating rod is disposed in the center region of the through hole so that the heating rod is spaced apart from each other to form a flow path. The method of claim 1,
And a temperature sensor for sensing a temperature of the heater unit and a pressure sensor for sensing a pressure of the fuel supply unit. The method of claim 1,
And the air supply unit is connected to a compressor mounted on the vehicle to compress and supply the atmosphere. The method of claim 1,
The fuel supply unit is connected to a fuel tank or a separate fuel tank for supplying fuel to the engine, the fuel injection device. An exhaust gas aftertreatment system comprising the fuel injection device of claim 1.

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