KR20140034143A - Miniature regeneration unit - Google Patents

Abstract

The system for controlling the temperature of the exhaust stream from the engine at an upstream position from the exhaust aftertreatment device includes a main exhaust passage adapted to receive the exhaust stream from the engine. The side branch is in communication with the main exhaust passage. The regeneration unit is located in the side branch for the combustion of fuel and the heating of the exhaust gas flowing through the main exhaust passage. The ion sensor can be operated to output a signal indicative of the pressure of fuel combustion. The controller optionally operates the regeneration unit to increase the exhaust temperature. The controller may be operable to control the supply of fuel to the regeneration unit based on the ion sensor signal.

Description

Miniature Regeneration Unit {MINIATURE REGENERATION UNIT}

The present invention generally relates to a system for treating exhaust gases. More specifically, miniature regeneration units for increasing the exhaust gas temperature are discussed.

In an attempt to reduce the amount of nitrogen oxides and particulate matter released to the atmosphere during internal combustion engine operation, a number of exhaust gas aftertreatment devices have been developed. The need for exhaust aftertreatment systems arises especially when the diesel combustion process is implemented. Common aftertreatment systems for diesel engine exhaust include one or more diesel particulate filters (DPFs), selective catalytic reduction (SCR) systems, hydrocarbon injectors (HC injectors), and diesel oxidation catalysts (DOCs). Can be.

During engine operation, diesel particle filters collect soot emitted by the engine and reduce emissions of particulate matter. Over time, the diesel particulate filter begins to load and become clogged. Periodic regeneration or oxidation of the gums collected in the diesel particle filter is necessary for proper operation. In order to regenerate the diesel particle filter, relatively high exhaust temperatures in combination with a sufficient amount of oxygen in the exhaust stream are needed to oxidize the gums collected in the filter.

Diesel oxidation catalysts are generally used to generate heat to regenerate diesel particulate filters that are full of gums. When hydrocarbons are sprayed onto the diesel oxidation catalyst at or above a particular light-off temperature, the hydrocarbons will oxidize. This reaction is highly exothermic and the exhaust gases are heated during activation. The heated exhaust gases are used to regenerate the diesel particle filter.

However, under many engine operating conditions, the exhaust gas is not hot enough to achieve a diesel oxidation catalyst active temperature of approximately 300 ° C. As such, diesel particle filter regeneration does not occur passively. In addition, nitrogen oxide adsorbers and selective catalytic reduction systems generally require a minimum exhaust temperature for proper operation.

Burners may be provided to heat the exhaust stream upstream of the various aftertreatment devices. Known burners successfully increase the exhaust temperature of internal combustion engines for automotive use. Some original equipment manufacturers have opposed the implementation of previous burners because of their size and cost. Besides. Other applications, including diesel locomotives, stationary power plants, ships, and the like, can be equipped with relatively large diesel compressor engines. The mass flow rate of the exhaust gas from a large engine can generally be at least ten times the maximum flow rate provided to the burner. It may be possible to increase the size of the burner to account for the increased exhaust gas mass flow rate, but concerns about the cost, weight, and packaging associated with this solution would not be acceptable. Thus, there may be a need for a compact regeneration unit to increase the temperature of the exhaust output from the engine while minimizing the cost, weight, size and performance of the exhaust system. It is also desirable to have minimal impact on the pressure drop and / or back pressure associated with the use of the burner.

This section provides a general summary of the invention and is not an exhaustive disclosure of its full scope or all of the features.

The system for controlling the temperature of the exhaust stream from the engine at an upstream position from the exhaust aftertreatment device includes a main exhaust passageway adapted to receive the exhaust stream from the engine. A side branch is in communication with the main exhaust passage. The regeneration unit is located in the side branch for the combustion of fuel and the heating of the exhaust gas flowing through the main exhaust passage. An ion sensor can be operated to output a signal indicative of the pressure of fuel combustion. The controller optionally operates the regeneration unit to increase the exhaust temperature. The controller may be operable to control the supply of fuel to the regeneration unit based on the ion sensor signal.

A system is provided for controlling the temperature of the exhaust stream from the engine at an upstream position from the exhaust aftertreatment device. The system includes a main exhaust passage adapted to receive an exhaust stream from the engine. A blind side branch is in communication with the main exhaust passage. The regeneration unit is located in the side branch for the combustion of fuel and the heating of the exhaust gas flowing through the main exhaust passage. The regeneration unit includes a housing located in the side branch of the side branch and away from the side wall, a nozzle for injecting fuel into the chamber defined by the housing, and an igniter for initiating combustion of the fuel in the housing. The controller optionally operates the regeneration unit to increase the exhaust temperature.

Another scope of applicability will become apparent from the description provided herein. The description and specific embodiments of this summary are for purposes of explanation and are not intended to limit the scope of the invention.

The drawings described herein are for purposes of illustration only and are not all possible implementations of the selected embodiments, and are not intended to limit the scope of the invention.
1 is a schematic diagram of a system for controlling the temperature of exhaust gas from an engine.
2 is a cross-sectional view of a portion of the exhaust aftertreatment system shown in FIG. 1 including a small regeneration unit.
3 is a cross-sectional view of an alternative regeneration unit.
4 is a cross-sectional view of an alternative regeneration unit.
5 is a cross-sectional view of an engine aftertreatment system including a flow diverter.
6 is a background of a post-processing system including a flow diverter.
7 is a partial background view of another alternative playback unit.
8 is a partial cross-sectional view of another alternative regeneration unit.
9-13 are background views showing alternative inlet tube portions of a regeneration unit.
14 is a sectional view of yet another alternative exhaust aftertreatment system.
Corresponding reference numerals indicate corresponding parts throughout the several views.

The preferred embodiments will now be described more fully with reference to the accompanying drawings.

1 shows an exhaust gas aftertreatment system 10 for treating the exhaust output by the preferred engine 12 to the main exhaust passage 14. An intake passage 16 is coupled to the engine 12 to provide combustion air therein. Turbocharger 18 includes a drive member (not shown) located in the exhaust stream. During engine operation, the exhaust stream causes the drive member to rotate and provide compressed air to the intake passage 16 before entering the engine 12.

The exhaust aftertreatment system 10 also includes a small regeneration unit 26 located upstream from the turbocharger 18 and upstream from a number of exhaust aftertreatment devices. In the preferred aftertreatment system shown in FIG. 1, the aftertreatment devices include a hydrocarbon injector 28, a diesel oxidation catalyst 30 and a diesel particle filter 32.

The regeneration unit 26 is located in the side branch portion 34 of the system in communication with the main exhaust passage 14. The regeneration unit 26 may be used to heat the exhaust gas passing through the passage 14 to a high temperature to improve the efficiency of the diesel oxidation catalyst 30 and allow regeneration of the diesel particle filter 32.

Regeneration unit 26 may include one or more injectors 36 for injecting appropriate fuel and oxygenator. Injector 36 may be configured as a combined injector for injecting both fuel and oxygen supply, as shown in FIG. 1, or may include separate injectors for fuel and oxygen supply (FIG. 11). Control to monitor and control the flow through the injector 36 and the ignition of fuel by the first igniter 42 using any suitable processor (s), sensors, flow control valves, electrical coils, and the like. Module 38 is provided.

The regeneration unit 26 includes a housing 50 that is configured as a multi-piece assembly of prefabricated metal parts. The housing 50 includes an inlet tube 52, a cylindrical body 54, and an outlet tube 56. An inlet header 58 is secured to the inlet tube 52. The inlet header 58 is fixed to the side branch portion 34 and surrounds one of its ends. Other single or multi-purpose inlet assemblies are also contemplated as being within the scope of the present invention. An annular volume 62 is present in the space between the inner surface 65 of the side branch portion 34 and the outer surface of the housing 50.

An injector mount is secured to the inlet tube 52 and / or the inlet header 58 to provide an attachment mechanism for the injector 36. The nozzle portion 66 of the injector 36 may comprise an inlet tube (such as in which atomized fuel can be injected at least partially into the primary combustion chamber 68 defined by the inner cylindrical surface 70 of the body 54). 52) Expand into. Injector 36 includes fuel inlet 72 and air inlet 74. The fuel inlet 72 is in communication with a fuel delivery system 76 including a fuel block 84 that is connected to each other by a fuel tank 78, a fuel filter 80, a fuel pump 82, and a fuel line 86. do. Operation of the components of the fuel delivery system 76 optionally provides hydrocarbons to the injector 36.

Secondary air system 90 includes a secondary air filter 92 and a Mass Air Flow (MAF) sensor 94. The compressor 96 receives air that has passed through the secondary air filter 92 and the intake air amount sensor 94. The compressor 96 may comprise part of a supercharger, a turbocharger or a standalone electric compressor. The air inlet 74 is provided with an output from the compressor 96. When exhaust gas heating is desired, fuel is injected via fuel inlet 72 and an oxygen supply is provided via air inlet 74 to inject a stream of atomized fuel. The first ignition device 42 is mounted to the side branch portion 34 downstream of the inlet header 58 and is operated to burn fuel provided by the injector 36 in the primary combustion chamber 68.

The side branch portion 34 intersects the exhaust passage 14 at an angle A of approximately 30 degrees. The flame produced by the regeneration unit 26 extends into the exhaust passage at approximately the same angle.

An elongate aperture 110 extends through the pipe 112 defining the main exhaust passage 14. A portion of the body 54 and the outlet tube 56 are located in the exhaust passage 14. The exhaust gas provided from the engine 12 affects the housing 50 and cools it during operation of the regeneration unit 26. In addition, since the housing 50 is minimally violated in the passage 14, the exhaust gas back pressure is also increased to a minimum. It should also be understood that the side branch portion 34 and the injector 36 extend radially outwardly from the pipe 112 to the minimum. Such an arrangement allows a custom branded manufacturer to more easily pack a small recycling unit on a vehicle.

In the aftertreatment system of the present invention, the first ignition device 42 also includes an ion sensor 44 coupled to the coil 46. Ion sensor 44 is in the form of an electrode located within combustion chamber 68. A voltage can be applied to the ion sensor to create an electric field from the sensor to ground, such as housing 50. When a voltage is applied, the electric field is released from the sensor to ground. If free ions are present in the electric field, a small ion current can flow. The magnitude of the ion current provides an indication of the density of the ions. The control module 38 detects and receives a signal from the ion sensor 44 to determine the presence or absence of a flame. Ion sensor 44 also determines if ignition device 42 is contaminated.

Contamination may occur through deposition of gum, oil, or other contaminants. When the ignition device 42 is contaminated, no proper combustion can occur. The control module 38 is operated to provide and stop the supply of fuel to fuel inlet 72, air to air inlet 74, and electrical energy to ignition 42. Prior to commencing provision of fuel and air to injector 36, control module 38 determines whether ignition 42 is contaminated via the signal provided by ion sensor 44. If it is determined that the ignition is ready for operation, the control module will determine the engine speed, ambient temperature, vehicle speed, engine coolant temperature, oxygen content, intake air volume, pressure differential across the diesel particulate filter 32, and various other factors. Many engines and vehicles can be described, such as vehicle parameters. If the control module 38 determines that an increase in air in the exhaust gas temperature is desirable, fuel and secondary air are provided to the injector 36. Coil 46 supplies electrical energy to ignition device 42 to initiate combustion in primary combustion chamber 68.

The control module 38 also includes the combustion and temperature of the exhaust gas in the passage 14 at a position downstream from the regeneration unit 26 to determine when to stop supply of fuel and air to the injector 36. Many other parameters can be evaluated. For example, control module 38 may be within regeneration unit 26, side branch 34, or main passage 14 to effect closed loop control by operating the regeneration unit to maintain the desired temperature at a particular location. Signals may be received from one or more temperature sensors located within. If combustion ends unexpectedly, the control module 38 stops supplying fuel. Other control schemes also exist within the scope of the present invention.

3 shows an alternative regeneration unit 26a coupled to the side branch portion 34. The regeneration unit 26a is substantially similar to the regeneration unit 26 except that the reduced or necked-down outlet tube portion of the housing 50 has been removed. As such, the same components will be identified with the "a" suffix. The main body portion 54a includes a substantially constant diameter ending at the outlet opening 53a.

4 shows another alternative playback unit identified with reference 26b. The regeneration unit 26b is substantially similar to the regeneration unit 26 except that the length L has been increased to cause a larger portion of the housing 50b to be located in the exhaust passage 14. . The same components will include a "b" suffix. The position of the ignition device 42 has been changed to be further from the end of the nozzle 66.

5 and 6 show yet another alternative arrangement comprising a diverter plate 140 located in a pipe 112 upstream of the small regeneration unit 26. The diverter plate 140 includes a D-shaped hole 142 that extends through it. The diverter plate 140 is positioned at an angle as shown in FIG. 5 to force exhaust flowing through the passage towards the housing 50 and around the housing 50. The diverted exhaust stream transfers heat from the regeneration unit 26 to the exhaust flowing through the pipe 112.

7 shows a part of another alternative playback unit identified with reference 26c. The regeneration unit 26c is substantially similar to the regeneration unit 26 except that the length of the outlet tube 56c includes a plurality of holes 144 that extend and extend therethrough. The extended outlet tube length and holes 144 ensure that the combustion flame is properly maintained and regulated during operation of the regeneration unit 26c. As the exhaust flows through the passage 14, a portion of the exhaust passes through the holes 144 which create a mixing effect that results in a more desirable temperature distribution, flame stability and flame quality.

8 shows another alternative playback unit identified with reference 26d. Regeneration unit 26d includes an additional housing portion 145 that defines secondary combustion chamber 146 as well as components of regeneration unit 26. The second ignition device 148 extends into the secondary combustion chamber 146. The plurality of holes 149 extend through the second housing 145 to allow exhaust gas to enter the secondary combustion chamber 146. Improved exhaust heating and mixing can be achieved through the use of the regeneration unit 26d.

9-13 illustrate alternative inlet tube configurations that may be used instead of the inlet tube 52. Each modified inlet tube includes a plurality of circumferentially spaced holes 150 that extend through the end wall 152. The holes 150 allow exhaust gas flowing through the passage 14 to enter the primary combustion chamber 68. By providing oxygen through the holes 150 into the primary combustion chamber, the pressure of the secondary air provided by the compressor 96 to the injector 36 will be reduced. The cost and size of the compressor 96 will also be reduced.

The inlet tube 52e shown in FIG. 9 includes a plurality of flaps 156e attached at one end to the end wall 152e. The flaps 155e are arranged to induce swirling of the gas passing through the holes 150e. FIG. 10 shows rectangular holes 150f without flaps. 11 includes a plurality of flaps 156g attached to the radially inner range of the holes 150g. The flaps 156g extend obliquely with respect to the exhaust flow in the radially outward direction. 12 relates to another alternative inlet tube assembly 52h having a plurality of holes 150h and a plurality of flaps 156h. Flaps 156h extend radially inward.

13 shows a plurality of circular holes 150i spaced circumferentially apart from each other. No flap partially blocks the holes. Each of the arrangements shown in FIGS. 9-13 provide a flow distribution in the primary combustion chamber 68 that is substantially similar.

Any of the described small regeneration unit arrangements that also include holes 150 may be moved secondary air inlet to inject compressed air into the annular volume 62 at a relatively low pressure, as shown in FIG. 14. It is contemplated that an injector 36j may be provided 74j. The fuel inlet 72j is positioned to inject the atomized fuel in the primary combustion chamber 68j, as previously described. Some of the air injected into the annular volume 62j passes through the holes 150i and the remaining portion of the secondary air passes over the outer surface of the housing 50j to cool the miniature regeneration unit 26j.

The description of the previous embodiments has been provided for the purpose of explanation. It is not intended to be exhaustive or to limit the invention. The individual components and features of a particular embodiment are generally not limited to that particular embodiment, but where applicable, although not specifically shown or described, replacement is possible and can be used in the selected embodiment. It can also vary in many ways. Such modifications are not to be considered outside the scope of the present invention, and all such modifications are intended to be included within the scope of the present invention.

10: Exhaust gas aftertreatment system
12: engine
14: main exhaust passage
16: intake passage
18: turbocharger
26: compact playback unit
28: hydrocarbon injector
30: diesel oxidation catalyst
32: diesel particle filter
34: side branch section
36: Injector
38: control module
42: first ignition device
44: ion sensor
46: coil
50: Housing
52: inlet tube
54: body
56: outlet tube
58: inlet header
62: illusion volume
65: inner surface of the side branch section
66: nozzle part of the injector
68: primary combustion chamber
70: inner cylindrical surface of the body
72: fuel inlet
74: air inlet
76: fuel delivery system
78: fuel tank
80: fuel filter
82: fuel pump
84 fuel block
86: Fuel Line
90: secondary air system
92: secondary air filter
94: intake air volume sensor
96: compressor
110: hole
112: pipe
140: diverter plate
142, 144 holes
145: second housing
146: secondary combustion chamber
148: second ignition device
150: hole
152: end wall
156e, 156g: flap

Claims (20)

A system for controlling the temperature of an exhaust stream from an engine at an upstream position from an exhaust aftertreatment device,
A main exhaust passage adapted to receive the exhaust stream from the engine;
A side branch in communication with the main exhaust passage;
A regeneration unit located in the side branch for burning fuel and heating exhaust gas flowing through the main exhaust passage;
An ion sensor operative to output a signal indicative of the presence of fuel combustion; And
And a controller, selectively operable to increase exhaust temperature, the controller operable to control the supply of fuel to the regeneration unit based on the ion sensor signal.
The system of claim 1, further comprising supplying a secondary source of oxygen to the control unit.
3. The system of claim 2, wherein the regeneration unit further comprises a housing defining a primary combustion chamber, wherein the secondary source of fuel and the oxygen is supplied directly to the primary combustion chamber.
4. The system of claim 3, wherein the housing includes a reduced diameter portion at the free distal end.
4. The housing of claim 3, wherein the housing includes a first end supported by the side branch and an unsupported second end, wherein the first end extends therethrough to receive a portion of the exhaust gas stream. System comprising a.
4. The system of claim 3, wherein the housing extends at least partially into the main exhaust passage to cool the housing.
4. The fuel cell of claim 3, wherein the regeneration unit further comprises a housing defining a main combustion chamber, the fuel is supplied directly to the primary combustion chamber, the secondary source of oxygen is supplied to an outer surface of the housing, And the housing allows a portion of the secondary source of oxygen to enter the primary combustion chamber.
The apparatus of claim 1, further comprising a diverter plate located in the main exhaust passage upstream from the regeneration unit, wherein the diverter plate comprises a hole shaped and positioned to direct exhaust gas flow towards the regeneration unit. System characterized in that.
9. The system of claim 8, wherein the aperture is substantially in the form of the letter D.
2. The system of claim 1, wherein the controller stops supplying fuel when the ion sensor signal indicates unexpected disappearance of fuel.
The system of claim 1 wherein the side branch crosses the main exhaust passage at approximately 30 degrees.
2. The system of claim 1, wherein the side branch has a distal end that extends into a main exhaust passage that is free of exhaust gas.
A system for controlling the temperature of an exhaust stream from an engine at an upstream position from an exhaust aftertreatment device,
A main exhaust passage adapted to receive the exhaust stream from the engine;
A blind side branch in communication with the main exhaust passage;
A housing located within the side branch and located within the side branch of the side branch and away from the side wall for combusting fuel and heating the exhaust gas flowing through the main exhaust passage, the fuel to a chamber defined by the housing A regeneration unit including a nozzle for injection, and an ignition device for initiating combustion of the fuel in the housing; And
And a controller for selectively operating the regeneration unit to increase the exhaust temperature.
14. The system of claim 13, further comprising supplying a secondary source of oxygen to the control unit.
15. The system of claim 14, wherein the housing includes a reduced diameter portion at the free distal end.
16. The housing of claim 15, wherein the housing includes a first end supported by the side branch and an unsupported second end, wherein the first end extends therethrough to receive a portion of the exhaust gas stream. System comprising a.
14. The system of claim 13, wherein the housing extends at least partially into the main exhaust passage to cool the housing.
14. The system of claim 13, further comprising a secondary air source supplied to the region between the housing and the side wall.
15. The apparatus of claim 13, further comprising a diverter plate located in the main exhaust passage upstream from the regeneration unit, wherein the diverter plate comprises a hole shaped and positioned to direct exhaust gas flow towards the regeneration unit. System characterized in that.
20. The system of claim 19, wherein the aperture is substantially in the form of the letter D.

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