Near-zero emitting diesel-electric locomotive using a high-speed diesel engine
11499459 · 2022-11-15
Assignee
- Catalytic Combustion Corporation (Bloomer, WI, US)
- Knoxville Locomotive Works, Inc. (Knoxville, TN, US)
Inventors
- James M. Wurtz, Jr. (Mokena, IL, US)
- Scott Gatewood (Knoxville, TN, US)
- Michael Thomason (Knoxville, TN, US)
- D. Todd Jacobs (Lago Vista, TX, US)
- Daniel R. Piche (Eau Claire, WI, US)
- Cody J. Molls (Chippewa Falls, WI, US)
- H. Peter Claussen (Knoxville, TN, US)
- John W. Robinson, JR. (Bloomer, WI, US)
Cpc classification
F01N3/022
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N2570/14
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N2590/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N3/035
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N2330/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N3/2892
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N2240/20
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Y02T10/12
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
F01N2610/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N2560/026
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N3/103
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N3/2066
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N3/021
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N2560/021
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F01N3/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F01N3/035
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A diesel-electric locomotive includes a diesel emissions reduction unit, including an inlet configured to receive an exhaust stream of a high-speed diesel engine; means for trapping at least a portion of diesel particulate matter contained in the exhaust stream; an aqueous NH.sub.3 dosing system including a dosing controller in communication with an electronic locomotive controller and a nitrogen oxide (“NO.sub.x”) concentration sensor and an ammonia (“NH.sub.3”) concentration sensor, at least one oxidation catalyst panel arranged to isolate the NO.sub.x concentration sensor from NH.sub.3 in the exhaust stream; mixing elements located between the dosing system and the NO.sub.x and NH.sub.3 concentration sensors to mix metered aqueous NH.sub.3 in the exhaust stream; a selective catalyst reactor bed located between the mixing elements and the NO.sub.x and NH.sub.3 concentration sensors; and an exhaust heating system in communication with at least one of the dosing and electronic locomotive controllers.
Claims
1. A diesel-electric locomotive comprising: an electronic locomotive controller (21) in communication with a diesel engine (11) having a designed operating rpm in a range of 1150 rpm to 2400 rpm; a traction generator (15) connected at one end to the diesel engine, the traction generator being at a same or a lower speed than that of the diesel engine; a diesel emissions reduction unit (30, 821) including: an inlet (825) configured to receive an exhaust stream of the diesel engine; means (31) for trapping at least a portion of diesel particulate matter contained in the exhaust stream; a dosing system (33) including a dosing controller (39) in electronic communication with the electronic locomotive controller (21) and a nitrogen oxide (“NO.sub.x”) concentration sensor (41, 111) and an ammonia (“NH.sub.3”) concentration sensor (43, 113), the dosing system configured to meter aqueous NH.sub.3 into the exhaust stream and including at least one oxidation catalyst panel (119) arranged to isolate the NO.sub.x concentration sensor from NH.sub.3 in the exhaust stream; one or more static mixing elements (35) located between the dosing system and the NO.sub.x and NH.sub.3 concentration sensors to mix the metered aqueous NH.sub.3 in the exhaust stream; a selective catalyst reactor bed (37, 823) located between the mixing elements and the NO.sub.x and NH.sub.3 concentration sensors; and an exhaust heating system (50) in communication with at least one of the dosing and electronic locomotive controllers, the exhaust heating system configured to heat the exhaust stream of the diesel engine toward the inlet of the diesel emissions reduction unit.
2. The diesel-electric locomotive of claim 1, further comprising: the means for trapping the diesel particulate matter including a diesel oxidation trap catalyst (410) comprised of a substrate (411) including one or more coated, corrugated, micro-expanded metal foil layers (413); each of said layers containing a plurality of eyes (419) with openings; a coating (421) of each said layer including a precious metal, a metal oxide, and a porous surface.
3. The diesel-electric locomotive of claim 2, the openings being in a range of 0.058 mm to 2.032 mm.
4. The diesel-electric locomotive of claim 2, the coating including a washcoat layer (423) being in a range of 80.5 g/l to 102.5 g/l and having a porous surface area in a range of 100 m.sup.2/g to 250 m.sup.2/g of the metal oxide.
5. The diesel-electric locomotive of claim 2, the precious metal being in a range of 0.071 g/l to 1.41 g/l.
6. The diesel-electric locomotive of claim 2, flow channels (427) per unit area of a face of the substrate being in a range of 15 cells/cm.sup.2 to 62 cells/cm.sup.2.
7. The diesel-electric locomotive of claim 1, further comprising: the NH.sub.3 concentration sensor located within an interior space (127) of an exhaust stack (115) of the diesel emissions reduction unit, toward an inlet end (125) of the exhaust stack; and a box (117) located within the exhaust stack, downstream and adjacent to the NH.sub.3 concentration sensor; the box including the at least one oxidation catalyst panel (119) and the NO.sub.x concentration sensor.
8. The diesel-electric locomotive of claim 7, further comprising: the NH.sub.3 concentration sensor and the NO.sub.x concentration sensor include a controller area network bus connector (C).
9. The diesel-electric locomotive of claim 7, wherein the NH.sub.3 concentration sensor and the NO.sub.x concentration sensor are mounted transverse to a longitudinal axis of the exhaust stack.
10. The diesel-electric locomotive of claim 1, further comprising, the mixing elements including: a mixing duct (800); at least two static mixer assemblies (801) located within the mixing duct, one of assemblies diverting exhaust flow in one direction and another of the assemblies diverting exhaust flow in another direction.
11. The diesel-electric locomotive of claim 1, the exhaust heating system 50 including at least one heater (51) including an electric heating element.
12. The diesel-electric locomotive of claim 11, the at least one heater connected to the traction generator.
13. A method of treating an exhaust stream of a diesel-electric locomotive, the diesel-electric locomotive including a diesel engine (11) having a designed operating rpm in a range of 1150 rpm to 2400 rpm, an electronic locomotive controller (21) in electronic communication with the diesel engine, and a traction generator (15) connected at one end to the diesel engine, the traction generator being at a same or a lower speed than that of the diesel engine; the method comprising: passing the exhaust stream into a diesel emissions reduction unit (30, 821), wherein the diesel emissions reduction unit includes: an inlet (825) configured to receive an exhaust stream of the diesel engine; means (31) to trap at least a portion of diesel particulate matter contained in the exhaust stream; a dosing system (33) including a dosing controller (39) in communication with the electronic locomotive controller (21) and a nitrogen oxide (“NO.sub.x”) concentration sensor (41, 111) and an ammonia (“NH.sub.3”) concentration sensor (43, 113), the dosing system configured to meter aqueous NH.sub.3 into the exhaust stream and including at least one oxidation catalyst panel (119) arranged to isolate the NO.sub.x concentration sensor from NH.sub.3 in the exhaust stream; one or more static mixing elements (35) located between the system controller and the NO.sub.x and NH.sub.3 concentration sensors to mix the metered aqueous NH.sub.3 in the exhaust stream; a selective catalyst reactor bed (37, 823) located between the mixing elements and the NO.sub.x and NH.sub.3 concentration sensors; and prior to the passing, heating the exhaust stream when a temperature of the exhaust stream falls below a predetermined reaction temperature.
14. The method of claim 13, wherein the means for trapping the diesel particulate matter include: a diesel oxidation trap catalyst (410) comprised of a substrate (411) including one or more coated, corrugated, micro-expanded metal foil layers (413); each of said layers containing a plurality of eyes (419) with openings; a coating (421) of each said layer including a precious metal, a metal oxide, and a porous surface.
15. The method of claim 14, wherein the openings being in a range of 0.058 mm to 2.032 mm; the coating including a washcoat layer (423) being in a range of 80.5 g/l to 102.5 g/l and having a porous surface area in a range of 100 m.sup.2/g to 250 m.sup.2/g of the metal oxide; the precious metal being in a range of 0.071 g/l to 1.41 g/l.
16. The method of claim 13, wherein: the NH.sub.3 concentration sensor is located within an interior space (127) of an exhaust stack (115) of the diesel emissions reduction unit, toward an inlet end (125) of the exhaust stack; and wherein a box (117) is located within the exhaust stack, downstream and adjacent to the NH.sub.3 concentration sensor; the box including the at least one oxidation catalyst panel and the NO.sub.x concentration sensor.
17. The method of claim 16, wherein the NH.sub.3 concentration sensor and the NO.sub.x concentration sensor include a controller area network bus connector (C).
18. The method of claim 15, wherein the NH.sub.3 concentration sensor and the NO.sub.x concentration sensor are mounted transverse to a longitudinal axis of the exhaust stack.
19. The method of claim 13, wherein the mixing elements include: a mixing duct (800): at least two static mixer assemblies (801) located within the mixing duct, one of assemblies diverting exhaust flow in one direction and another of the assemblies diverting exhaust flow in another direction.
20. The method of claim 13, wherein the heating includes at least one heater containing an electric heating element.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
(16) For the purposes of this disclosure, a specified range also discloses narrower subranges within the range, as well as individual discrete values within the range. A high-speed locomotive diesel engine is a locomotive diesel engine operating above approximately 1150 rpm to 1800 and up to-2400 rpm, there being subranges within this broader range. Horsepower rating may be in a range of about 1000 bhp (brake horsepower) to approximately 3220 bhp. A medium-speed locomotive diesel engine is a locomotive diesel engine operating in a range from 800-1150 rpm, Horsepower rating may be up to about 4800 bhp. Light engine load means when the locomotive diesel engine is idling or when the throttle control is in the first (slowest speed) position or notch, the engine exhaust temperature being below about 410° F. (210° C.).
(17) Referring to
(18) In embodiments, the high-speed diesel engine 11 may be operated to rotate a generator 15 or alternator which provides direct current electrical power that is utilized by traction motors to move the locomotive forward and reverse and 3-phase alternating current which powers auxiliary equipment such as cooling fans and blower motors. The electronic locomotive control system 20 precisely controls the diesel engine 11 in the most efficient way possible and allocates electrical power to the traction motors to move the locomotive and controls all auxiliary electrical loads. An auxiliary drive assembly (“ADA”) may contain an air compressor, an auxiliary generator and/or electric motor(s) mechanically driven at optimal speed directly by the diesel engine 11.
(19) The high-speed diesel engine 11 may be combined with a high-speed alternator (which is traditionally done in the art) or it may be combined with a lower speed alternator through a gear reduction gearbox 17 so that a lower speed traction generator 15 may be used. A control system 19 like that disclosed by Claussen may be used to dampen torsional vibration generated by the high-speed engine 11 from being transmitted to the rigidly mounted generator 15 as well as mitigating misalignment caused by engine movement.
(20) The diesel emission reduction system 30 may include one or more of the following features: means 31 to reduce DPM such as a diesel particulate filter (“DPF”) of a kind known in the art or a diesel oxidation trap catalyst (“DOTC”) of this disclosure, a dosing system 33 to precisely meter a liquid-reductant agent such as diesel exhaust fluid (“DEF”) into an injection duct of a selective catalytic reactor (“SCR”) system; mixing elements 35 configured to create a homogeneous mixture of ammonia (“NH.sub.3”) in the exhaust stream prior to an SCR catalyst 37); a closed-loop dosing control system including a controller 39 and NO.sub.x and NH.sub.3 concentration sensors 41, 43 (which may include a controller area network (“CAN”) bus connector C) arranged to prevent cross-interference of the NOx sensor 41 by excess NH.sub.3 in the exhaust stream; and an engine exhaust heating system to automatically provide the exhaust temperatures necessary for the diesel emission reduction system 30 to reduce emissions at light engine loads where native engine exhaust temperatures are not sufficient for system operations. In some embodiments, the heater 51 is powered by a traction generator 15.
Engine exhaust is routed through the diesel emission control system 30 where the diesel emissions are converted to nitrogen, water vapor and CO.sub.2. In embodiments, the electronic locomotive control system 20 and the liquid-reductant agent dosing system 33 communicate so that the emission control system will precisely inject the agent, such as DEF, appropriately based upon engine operation. Low sulphated ash engine oils of a kind known in the art may also be used.
(21) The closed loop dosing control system 39 controls the amount of liquid-reductant agent or DEF that is metered into the exhaust stream via a targeted NO.sub.x value, utilizing a NO.sub.x concentration sensor 41 to sense the amount of NO.sub.x in the exhaust stream. Oxidation catalyst panels, see e.g.
(22) In embodiments, one or more heaters 51 are integrated into the emission control system reactor and generate heat necessary for the emission reduction reactions to occur in the emission control system 30 when the engine is operating at light loads and not generating a high enough exhaust temperature to support system operation. At these loads heating system 50 may be employed to raise the native engine exhaust temperature to one that facilitates or enables the reaction temperature. In embodiments, the heating system 50 raises the temperature of the exhaust above the native engine exhaust temperature at a given load to a second higher temperature at that same load, the second higher temperature being in a reaction temperature range. By way of a non-limiting example, native engine exhaust temperatures at light loads can be below 410° F. (210° C.). At idle the native engine exhaust temperature may typically be about 350° F. (176.7° C.). In a first notch position, it may take the engine upwards of about 20 minutes or so for temperatures to reach 410° F. (210° C.). The heating system may raise the exhaust temperature to predetermined reaction temperature in a range of 400° F. to 460° F. (204.4° C. to 237.8° C.), 410° F. to 450° F. (210° C. to 232.2° C.), 415° F. to 445° (212.8° C. to 229.4° C.), 420° F. to 440° (215.6° C. to 226.7° C.), 425° F. to 435° (218.3° C. to 223.9° C.), 427° F. to 432° (229.4° C. to 222.2° C.), and 430° (221.1° C.), there being subranges within these ranges. In embodiments in which an electric heater 51 is used, the heater 51 may be powered by the traction generator 15 and jointly controlled by the electronic locomotive control system 20 and the dosing system controller 39. By way of a non-limiting example, process temperature may be provided by the dosing system controller 39 and over-temperature protection of the heater 51 may be controlled by the electronic locomotive control system 20. Process control of the heater 51 may be through the electronic locomotive control system 20 based upon engine load, process temperature, and throttle demand.
(23) Referring now to
(24) The corrugated pattern 425 may include a herringbone-style pattern that, when in use, is oriented in a longitudinal direction L of the diesel engine exhaust flow (transverse T to the eye 419), with flow impinging on the metal foil strand walls 423 surrounding the eyes 419. The micro-expanded metal foil provides small openings or eyes that, as the exhaust flow passes through the catalyst (transverse to the eye opening), DPM in the flow impinges on the surface and becomes trapped in the eyes. The density of cells of the corrugated pattern 425—defined as the number of flow channels 427 per unit area of a catalyst face 429—may be in a range of about 100 cells/in.sup.2 (15 cells/cm.sup.2) to about 400 cells/in.sup.2 (62 cells/cm.sup.2), there being subranges within this broader range.
(25) In some embodiments, the DOTC includes a substrate 411 containing one or more coated, corrugated, micro-expanded metal foil layers, each of the layers 413 containing a plurality of eyes 419 containing openings in a range of 0.020 inches to 0.080 inches (0.058 mm to 2.032 mm). A coating 421 of each layer 413 may include a precious metal, a metal oxide, and a porous surface area—as measured by the Brunauer, Emmett, and Teller (“BET”) method—in a range of 100 m.sup.2/g to 250 m.sup.2/g (488,246 ft.sup.2/lb to 1,220,616 ft.sup.2/lb) of the metal oxide, there being sub-ranges ranges within this broader range. The mass loading of the washcoat layer 421 may be about 1½ g/in.sup.3 (91.54 g/l) or in a range of 80.5 g/l to 102.5 g/l. A precious metal loading may be on top of or in addition to this washcoat loading. The precious metal may be a platinum group metal—ruthenium, rhodium, palladium, osmium, iridium, and platinum—or a platinum group metal alloy or bi-metallic catalyst. The precious metal may also comprise or include gold or silver.
(26) Referring now to
(27) Located within the mixing duct 800 is at least one static mixer assembly 801. The static mixer assembly 801 may be located downstream of a first catalyst surface, such as an oxidation catalyst of this disclosure, over or through which the exhaust gas stream may flow. A urea or ammonia injection lance 805 may be fitted upstream of the static mixer assembly 801 and configured to inject the urea or ammonia into the mixing duct 800. A dosing turndown ratio of the injection lance 805 in combination with the mixing duct 800, over a dynamic range of exhaust gas flow, may be in a range of 4:1 to 10:1. The mixed exhaust-reagent stream may then pass through a SCR catalyst bed 803.
(28) By way of a non-limiting example, in embodiments the mixing duct 800 may contain two or more static mixer assemblies 801, with one assembly 801 configured to divert flow in one direction and another assembly 801 configured to divert flow in another direction. Another of the assemblies 801 may be configured to channel flow to a certain portion of the duct 800. A mixing blade set 819 may be located downstream of the SCR catalyst bed 803 and arranged to remix all molecules just upstream of the NOx sensor and ammonia (NH.sub.3) slip sensor.
(29) In embodiments, the mixing quality achieved, as measured by root-mean-square (“RMS”) deviation for the NOx and ammonia concentration, may be less than 3%, and may be in a range or 0.25% to 2.75%. In some embodiments, the RMS deviation is no greater than 1%.
(30) Referring now to
(31) In embodiments, the control loop 110 includes an NH.sub.3 slip sensor 113 located within an interior space 127 of an exhaust stack 115 of an SCR reactor and a linear box 117 located downstream and adjacent to the NH.sub.3 slip sensor. The linear box 117 includes face panels 119 that surround and isolate the NO.sub.x sensor 111 contained within an interior space defined by the face panels 119. Two of the face panels 119B, 119T, one on an inlet flow side 121 of the box 117 and another on the outlet flow side 123, contain an oxidation catalyst. The NH.sub.3 slip sensor 113 and the NO.sub.x sensor 111 are mounted sideway to the stack 115 and may include a controller area network (“CAN”) bus connector. The NO.sub.x sensor 111 is located in the box 117, the NH.sub.3 slip sensor 113 is bolted in the stack 115, aside the linear box 117 and not in the linear box 117. The linear box 117 may be sized to handle or accommodate no more than 10%, no more than 5%, and no more than 1% of the total exhaust flow through the stack 115.
(32) Because of this arrangement, the NO.sub.x sensor 111 reading is:
NO.sub.x sensor reading=NO.sub.x real value+NH.sub.3 slip real value (Eq. 1)
Because the NH.sub.3 slip sensor 113 is located outside of the linear box 117, the sensor 113 is reading a real (true) value for the NH.sub.3 slip in the exhaust gas stream with no bias to other molecules. In other words, the NH.sub.3 slip sensor 113 may be used to make an accurate and precise bias correction in real time to the NO.sub.x sensor 111 reading. Therefore,
NO.sub.x real value=NO.sub.x sensor reading−NH.sub.3 sensor reading (Eq. 2)
This real value may then be used by the injection control system.
(33) Embodiments of using high-speed diesel engine of this disclosure significantly reduces fuel consumption and lube oil consumption compared to prior art medium-speed diesel engines for which the emission reduction and control of this disclosure is unachievable. By way of a non-limiting example, in embodiments of this disclosure fuel consumption is reduced between 10% and 50% when compared to a typical medium-speed diesel engine used in other locomotives of similar size and horsepower, there being subranges within this broader range. Oil consumption is reduced by at least 50% or more, 50% to 80%, 55% to 75%, 60% to 70%, 63% to 67%, there being subranges within this broader range. In embodiments of the diesel emission control system, emissions from the locomotive diesel engine are reduced, in comparison to EPA Tier 4 emission standards for newly built and newly re-manufactured locomotives, as follows: DPM emissions >50%; NO.sub.x emissions >85%; and CO and NMHC emissions >98%. The Tier 4 emission standards are incorporated by reference herein. The system of this disclosure may be configured to achieve more stringent emission standards, such as but not limited to, the proposed (2025) California Air Resources Board Near Zero emissions standards for NOx and DPM.
(34) While embodiments of an ultra-low emitting diesel-electric locomotive using a high-Speed diesel engine have been described, the system, apparatuses, methods of its use are capable of modification by persons of ordinary skill in the art without departing from the scope of this disclosure. The claims include the full range of equivalents to which each recited element is entitled.