EP2526268A1

EP2526268A1 - Engine system with exhaust-cooled fuel processor

Info

Publication number: EP2526268A1
Application number: EP10840265A
Authority: EP
Inventors: Jacobus Neels
Original assignee: Westport Power Inc
Current assignee: Westport Power Inc
Priority date: 2009-12-31
Filing date: 2010-12-24
Publication date: 2012-11-28
Also published as: US20120297752A1; EP2526268A4; WO2011079396A1

Abstract

An engine system comprises a fuel processor that is supplied with air and a fuel stream to produce a hydrogen-containing gas stream. The fuel processor comprises a housing, and at least a portion of the housing is located within an exhaust stream conduit from the engine. During operation of the engine, heat transfer between the fuel processor and the engine exhaust stream occurs. An exhaust after- treatment assembly is located downstream of the fuel processor and is connected to selectively receive hydrogen-containing gas stream from the fuel processor.

Description

ENGINE SYSTEM WITH EXHAUST-COOLED

FUEL PROCESSOR

Cross-Reference to Related Application(s)

[0001] This application is related to and claims priority benefits from U.S. Provisional Patent Application Serial No. 61/291 ,727 entitled "Engine System with Exhaust-Cooled Fuel Processor", filed on December 31, 2010, which is hereby incorporated by reference in its entirety.

Field of the Invention

[0002] The present invention relates to engine systems that include a fuel processor, and methods of operating engine systems that include a fuel processor for producing a hydrogen-containing gas stream, such as a syngas stream. The present apparatus and methods are particularly applicable to engine system applications where a hydrogen-containing gas is required, reduced fuel consumption is desired, and space is limited.

Background of the Invention

[0003] For engine systems in vehicular or other mobile applications where a supply of hydrogen is required, due to challenges related to on-board storage of a secondary fuel and the current absence of a hydrogen refueling infrastructure, hydrogen is preferably generated on-board using a fuel processor. The product stream from the fuel processor can be used to regenerate, desulfate and/or heat engine exhaust after-treatment devices, can be used as a supplemental fuel for the engine, and/or can be used as a fuel for a secondary power source, for example, a fuel cell.

[0004] One type of fuel processor is a syngas generator (SGG) that can convert a fuel into a gas stream containing hydrogen (¾) and carbon monoxide (CO), known as syngas. Air or other oxygen- containing streams can be used as an oxidant for the fuel conversion process. Steam and/or water can optionally be added. The SGG can be conveniently supplied with a fuel comprising the same fuel that is used to operate the engine. Alternatively a different fuel can be used, although this would generally require a separate on-board secondary fuel source and supply system specifically for the SGG. The H₂ and CO can be beneficial in processes used to regenerate exhaust after- treatment devices. For other applications, such as use as a fuel in a fuel cell, the syngas stream may require additional processing prior to use.

[0005] In vehicular or other mobile applications, an on-board SGG should generally be fuel efficient, low cost, compact, light-weight and efficiently packaged with other components of the engine system. Known methods of employing a fuel processor in an engine system include: [0006] (a) configuring the fuel processor as a separate subassembly external to the engine and/or exhaust subsystems of the engine system, as illustrated in FIG. 1 , and

[0007] (b) integrating the fuel processor "in-line" to form part of an exhaust stream conduit from the engine, and employing the exhaust stream as an oxidant reactant for the fuel processor, as illustrated in FIG. 2.

[0008] FIG.l is a simplified schematic diagram illustrating a representative prior art engine system 1 comprising an engine 2, fuel processor or syngas generator (SGG) 6, and an exhaust subsystem comprising, for example, exhaust conduit 3, exhaust after-treatment assembly 4, and exhaust conduit 5. The fuel processor is arranged separately from and external to combustion engine 2 and exhaust subsystem of the overall engine system 1. In FIG. 1, engine 2 produces an exhaust stream that exits and flows through exhaust conduit 3, exhaust after-treatment assembly 4, and exhaust conduit 5 in the exhaust subsystem before exiting into the atmosphere.

Additional devices (not shown in FIG. 1) can be employed in the exhaust subsystem including, for example, one or more turbo- compressors, heat exchangers, valves, sensors, and additional conduits. Exhaust after-treatment assembly 4 can comprise one or more devices that can reduce regulated emissions. Some or all of the devices in exhaust after-treatment assembly 4 can at least periodically be heated or regenerated by a product stream from fuel processor 6. For example, exhaust after-treatment assembly 4 can comprise a diesel oxidation catalyst device (DOC), a lean NO_x trap (LNT), a selective catalytic reduction (SCR) device and/or a diesel particulate filter (DPF). SGG 6 can be supplied with fuel reactant stream from fuel tank 7 via fuel conduit 8, and an oxidant reactant stream via air conduit 10 and air blower 9. Optionally, the oxidant reactant comprises, or consists of, at least a portion of the exhaust stream from engine 2, in which case there could be a conduit and associated valves linking exhaust conduit 3 and SGG 6. The fuel and oxidant reactant streams are converted into a product stream that is directed from SGG 6 into exhaust after-treatment assembly 4 via SGG outlet conduit 11 , diverter valve 12, supply conduit 13 and exhaust conduit 3. Diverter valve 12 can distribute the flow of the product stream to exhaust after- treatment assembly 4 and/or one or more other hydrogen-consuming devices (not shown in FIG. 1). The term "product stream" herein refers to an output stream from a fuel processor, including, for example, a hydrogen-containing stream, a syngas stream or a flue gas stream (the latter obtained through complete or almost complete combustion of the fuel within the fuel processor). In the system illustrated in FIG. 1, SGG 6 is configured separately from engine 2, exhaust conduit 3 and exhaust conduit 5, but is fluidly connected to exhaust after-treatment assembly 4. [0009] Some shortcomings associated with configuring a fuel processor as a separate assembly from the engine and/or exhaust subsystems of an engine system include, for example:

[0010] (a) lower thermal efficiency, as a substantial amount of heat produced by the fuel processor is dispersed into the atmosphere as waste heat without being utilized by the engine system;

[0011] (b) increased volume and/or footprint for the fuel

processor sub-assembly as the fuel processor and ancillary components (including, for example, reactant supply subsystems, flow diverter, conduit(s), and cooling system) occupy additional space; and/or

[0012] (c) increased pressure drop across the fuel processor subassembly as, for example, the conduits and diverter valve employed for the product stream contribute to the overall pressure drop across the assembly.

[0013] FIG. 2 is a simplified schematic drawing illustrating a prior art engine system 21 in which a fuel processor 26 is configured "inline" with the exhaust stream conduits 23 and 25, and exhaust after- treatment assembly 24 of an engine 22. Engine 22 produces an exhaust stream that exits engine 22 and flows through exhaust conduit 23, and then directly into fuel processor 26, and on into exhaust after- treatment assembly 24 before exiting into the atmosphere via exhaust conduit 25. Exhaust after-treatment assembly 24 can comprise one or more devices that can reduce regulated emissions, for example, a DOC, LNT, SCR, and/or a DPF. Some or all of the devices in exhaust after-treatment assembly 24 can at least periodically be heated or regenerated by a product stream from fuel processor 26. Some or all of the oxygen-containing exhaust stream from engine 22 is employed as an oxidant reactant in fuel processor 26. For example, engine system 21 can be configured such that substantially the entire exhaust stream from engine 22 and/or exhaust conduit 23 is directed through fuel processor 26 (as shown in FIG. 2), or so that a portion of the engine exhaust stream is directed through fuel processor 26 (for example, there could be a bypass conduit or another conduit for the remainder of the exhaust stream). When a product stream is desired from fuel processor 26, fuel from fuel tank 27 is introduced via fuel conduit 28 into exhaust conduit 23, and mixes with the exhaust stream upstream of fuel processor 26. Fuel processor 26 typically comprises a monolith with a catalytic washcoat, which can catalytically convert the combined fuel and engine exhaust stream into a product stream. The combined engine exhaust gas and/or fuel processor product stream flows into exhaust after-treatment assembly 24, where it may be employed, before flowing into exhaust conduit 25 and exiting into the atmosphere. [0014] Some shortcomings associated with configuring a fuel processor "in-line" with the exhaust subsystem, where the exhaust stream of an engine is employed as the oxidant reactant in the fuel processor, include the following:

[0015] (a) Some parameters of the exhaust stream produced by the engine, such as mass flow, pressure, temperature, composition and emission levels, vary significantly over the operating range and depend upon the operating condition of the engine. If the fuel processor employs an engine exhaust stream as the oxidant reactant, the variable parameters affect the ability to accurately and repeatedly control the air- fuel ratio of the reactants and resulting product stream output of the fuel processor;

[0016] (b) The product stream output required from the fuel processor is typically variable. The product stream is preferably generated as-needed in accordance with the variable demand from devices in the engine system, and independent of the operating condition of the engine. For example, the demand for product stream from the fuel processor may be great during periods when the exhaust stream has a reduced concentration of oxygen; [0017] (c) An in-line configuration of the fuel processor is suitable only for engine systems and operating conditions where the exhaust stream of the engine contains an appropriate level of oxygen. For example, it may be limited to lean burn engine systems where a sufficient level of oxygen is present in the exhaust stream over a large portion of the operating range of the engine; and/or

[0018] (d) The fuel processor can be operated only when the engine is producing an exhaust stream.

[0019] In the present approach a fuel processor is integrated within an engine system in such a way that at least some of the shortcomings discussed above are addressed.

Summary of the Invention

[0020] In a first aspect, an engine system comprises an engine that during operation produces an exhaust stream, an exhaust stream conduit connected to receive the exhaust stream from the engine, and a fuel processor for producing a product stream. The fuel processor further comprises a housing, an oxidant inlet conduit fluidly

connected to receive an air stream, and a fuel inlet fluidly connected to receive a fuel stream. At least a portion of the housing of the fuel processor is located within the engine exhaust stream conduit. In some embodiments the housing is entirely located within the engine exhaust stream conduit. An exhaust after-treatment assembly, for at least periodically reducing regulated emissions in the exhaust stream, can be located downstream of the fuel processor and is connected to selectively receive the product stream from the fuel processor.

[0021] In a second aspect, an engine system comprises an engine, an exhaust conduit and a fuel processor located within the exhaust conduit. The fuel processor comprises an interior reaction chamber. Preferably the interior reaction chamber is fluidly connected to receive fuel from a fuel supply subsystem and oxidant from an oxidant supply subsystem located external to the exhaust conduit and engine. An exhaust after-treatment assembly, for at least periodically reducing regulated emissions in the exhaust stream, can be located downstream of the fuel processor and is connected to selectively receive the product stream from the fuel processor.

[0022] In embodiments of any of the above-described engine systems, the fuel processor is a non-catalytic fuel processor. In embodiments of any of the above-described engine systems, the engine system can further comprise a further hydrogen-consuming device, with the fuel processor further comprising a product stream conduit to supply a hydrogen-containing product stream to the hydrogen consuming device. [0023] In a method of operating an engine system comprising an engine, an exhaust after-treatment assembly, and a fuel processor comprising an housing and an interior reaction chamber, the method comprises:

[0024] (a) operating the engine system to produce an engine

exhaust stream;

[0025] (b) directing at least a portion of the engine exhaust

stream to at least one exhaust after-treatment device in the exhaust after-treatment assembly for reducing regulated emissions in the engine exhaust stream;

[0026] (c) introducing a fuel and an air stream into the interior reaction chamber of the fuel processor and operating the fuel processor to produce a product stream; and

[0027] (d) at least periodically introducing at least a portion of the product stream into the exhaust after-treatment device, for example, for heating or regenerating the exhaust after-treatment device;

[0028] wherein during operation of the engine, at least a portion of the engine exhaust stream flows over at least a portion of the fuel processor housing. [0029] The fuel processor can be operated to produce and introduce at least a portion of the product stream into the exhaust after-treatment assembly during operation of the engine and/or after the engine has been shut off, and/or prior to starting operation of the engine and/or during start-up of the engine. For example, in some embodiments of the method, the fuel processor can be operated to produce and introduce at least a portion of the product stream into the exhaust after-treatment assembly when the exhaust after-treatment assembly is below a threshold temperature value.

[0030] In certain embodiments of the method, the fuel processor is located within an exhaust conduit of the engine; however, the fuel processor interior reaction chamber does not receive engine exhaust directly from the exhaust stream conduit.

[0031] In embodiments of the above-described method, the fuel processor can at times be operated to produce a product stream that is a hydrogen-containing gas stream, and at other times can be operated to produce a product stream that is a flue gas stream. The product stream from the fuel processor can be introduced to another hydrogen- consuming device other than, or in addition to, the exhaust after- treatment assembly. Brief Description of the Drawings

[0032] FIG. 1 is a simplified schematic diagram illustrating a conventional, prior art engine system comprising a fuel processor, where the fuel processor is configured separately from the engine and exhaust stream conduit.

[0033] FIG. 2 is a simplified schematic diagram illustrating a conventional, prior art engine system comprising a fuel processor, where the fuel processor is configured "in-line" with the exhaust stream conduit from the engine. The fuel processor is directly fluidly connected to the engine so that at least a portion of the engine exhaust stream is employed as an oxidant reactant in the fuel processor.

[0034] FIG. 3 is a simplified schematic diagram of an embodiment of an engine system comprising a fuel processor, with the fuel processor located within an engine exhaust stream conduit so that during operation of the engine heat transfer between the fuel processor and the engine exhaust stream occurs. The fuel processor employs an oxidant reactant that is supplied from an external source, for example, an air blower.

[0035] FIG. 4a is an end view showing an example of how a fuel processor can be located within an engine exhaust stream conduit in an engine system. [0036] FIG. 4b is a cross-sectional view of the fuel processor located within an engine exhaust stream conduit in an engine system, as illustrated in FIG. 4a, along section A-A.

Detailed Description of Preferred Embodiments)

[0037] In embodiments of the present system and method, in which an engine system comprises a fuel processor, such as a syngas generator, the fuel processor further comprising a housing is located within an engine exhaust stream conduit so that so that during operation of the engine, heat transfer between the fuel processor and the engine exhaust stream occurs. However, the interior reaction chamber of the fuel processor is substantially enclosed in a housing and is not fluidly connected to receive engine exhaust directly from the engine exhaust stream conduit, but rather is supplied with an oxidant reactant stream from another source separate from the exhaust stream of the engine, for example, a blower, air compressor, or engine air intake manifold, or from a supercharger or turbo-compressor of an engine. The fuel processor produces a product stream including, for example, a hydrogen-containing gas stream, syngas stream or flue gas stream, and/or sensible heat that can be beneficially employed by a downstream device or process. For example, it can be used to regenerate or enhance the performance of one or more exhaust after- treatment devices, as a supplemental fuel for an engine, as a fuel for a fuel cell, and/or in other hydrogen consuming devices. [0038] FIG. 3 is a simplified schematic diagram of a preferred embodiment of an engine system 31 comprising engine 32 that produces an exhaust stream that flows into exhaust conduit 33, through an exhaust after-treatment assembly 34 and outlet conduit 35, before exiting into the atmosphere. Engine 32 can be, for example, a lean burn combustion engine. Exhaust after-treatment assembly 34 can reduce the amount of regulated emissions in the exhaust stream and can include one or more valves, sensors, conduits, branches and/or exhaust after-treatment devices including, for example, a diesel oxidation catalyst (DOC), lean NO_x trap (LNT), selective catalytic reduction (SCR), and/or diesel particulate filter (DPF).

[0039] Engine system 31 also comprises a fuel processor, in this embodiment a syngas generator (SGG) 36. SGG 36 comprises a housing (not shown in FIG. 3) that substantially encloses an interior reaction chamber (not shown in FIG. 3) where fuel reforming and combustion reactions occur. SGG 36 is located within exhaust conduit 33 so that during operation of engine 32, heat transfer between SGG 36 and the engine exhaust stream occurs. For example, SGG is configured so that at least a portion of the exhaust stream from engine 32 flows over at least a portion of the housing of SGG 36, and so that the exhaust stream can beneficially transfer sensible heat from SGG 36 to downstream exhaust after-treatment assembly 34. Optionally one or more exhaust after-treatment devices can be located upstream of SGG 36 and/or one or more fuel processors can be located within exhaust conduit 33. Also optionally, one or more exhaust legs and/or exhaust after-treatment devices can be configured in parallel downstream of one or more fuel processors.

[0040] In the illustrated embodiment, rather than receiving at least a portion of the engine exhaust stream from exhaust conduit 33, the reaction chamber of SGG 36 is supplied with air (or another oxidant reactant stream) via an oxidant supply subsystem (located external to exhaust conduit 33) comprising oxidant conduit 40 and blower 39. Optional devices (not shown in FIG. 3) including, for example, valves, filters, sensors, metering devices, can be employed within the oxidant supply subsystem and/or along oxidant conduit 40. A fuel reactant stream from a fuel supply subsystem (comprising fuel tank 37 and fuel conduit 38) is introduced into SGG 36, via fuel conduit 38. This can be the same tank from which fuel is supplied to engine 32, or can be a separate tank. Optional devices (not shown in FIG. 3) including, for example, valves, filters, sensors, a fuel pump and/or fuel metering device, can be employed within the fuel supply subsystem and/or along fuel conduit 38. The supply of fuel and oxidant reactant streams and operation of SGG 36 are controlled by a controller 60. The product stream exits SGG 36 through an outlet port (not shown in FIG. 3), into the exhaust stream, at conditions desired for regeneration of exhaust after-treatment devices. The SGG product stream optionally combines with the engine exhaust gas stream, flows through exhaust conduit 33 into exhaust after-treatment assembly 34, where it may be employed, before flowing into outlet conduit 35 and exiting into the atmosphere. Optionally the product stream from SGG 36 can be diverted to other hydrogen-consuming devices or other components (not shown in FIG. 3) in engine system 21 via valves and conduits (not shown in FIG. 3). SGG 36 can be operated when the engine is not running or substantially independently of engine operation.

[0041] SGG 36 can reach extreme temperatures and can produce a product stream that can be hot, flammable, and hazardous. For example, SGG 36 can be a non-catalytic partial oxidation fuel processor, which during normal operation, along with the product stream, can reach temperatures up to about 1400°C. Locating SGG 36 within exhaust conduit 33 offers personnel protection from the extreme temperatures of the SGG and can act to contain leakage of potentially flammable and harmful gasses from the SGG if leakage occurs. This containment feature can reduce the requirement for flammable and/or hazardous gas sensors, enable a higher operating pressure for the SGG and/or offer the advantages of reducing the complexity, cost, weight and volume of SGG 36.

[0042] Furthermore, locating SGG 36 within exhaust conduit 33 can reduce the need for a product stream conduit and diverter valve, which can advantageously reduce the pressure drop across SGG 36, and/or reduce the power required and energy consumed to compress W

- 17 - the oxidant reactant stream supplied to SGG 36, and/or reduce the complexity, cost, weight and volume of SGG 36.

[0043] At least periodically, SGG 36 is operated to produce and introduce a product stream including, for example, a hydrogen- containing (syngas) stream or a flue gas stream, to heat or regenerate one or more components of exhaust after-treatment assembly 34. The equivalence ratio (ER) of the reactants introduced into SGG 36 can be adjusted to change the composition and temperature of the product stream, for example to produce a syngas stream or a flue gas stream. The term equivalence ratio (ER) herein refers to the ratio between the actual amount of oxygen supplied and the theoretical stoichiometric amount of oxygen that would be required for complete combustion of the fuel. An ER of greater than 1 represents a fuel lean mode (excess oxygen) that typically creates a flue gas stream, while an ER of less than 1 represents a fuel rich mode (excess fuel) that typically creates a syngas stream. SGG 36 can be operated when the engine is not running or substantially independently of engine operation.

[0044] Turning to FIGs. 4a and 4b, FIG. 4a is an end view showing an example of how a fuel processor such as a syngas generator can be located within an engine exhaust stream conduit in an engine system, while FIG. 4b is a cross-sectional view of the syngas generator arrangement illustrated in FIG. 4a, along section A-A. In FIGs. 4a and 4b, spacers 41 assist in locating and holding SGG 46 within exhaust conduit 43 and create plenum 42 where an engine exhaust stream can flow over housing 50 of SGG 46. Housing 50 encloses an interior reaction chamber 51 where fuel reforming and combustion reactions occur. Spacers 41 can also serve as heat transfer surfaces or fins. Plenum 42 is fluidly connected, for example, to an upstream engine exhaust conduit and to a downstream exhaust after-treatment assembly (both not shown in FIGs 4a and 4b). An externally supplied oxidant reactant stream, for example, an air stream supplied by a blower, is introduced into SGG 46 via oxidant conduit 44. A fuel reactant stream is introduced into SGG 46 via fuel conduit 45. The reactants are converted into a product stream (for example, a syngas or flue gas stream) within SGG 46, before exiting SGG 46, via cap 47 into plenum 42. When both the engine and SGG are operating, the product stream mixes with and is transported by the exhaust stream that flows through plenum 42, creating a mixed gas stream. The mixed gas stream flows downstream to an exhaust after-treatment assembly where it can be beneficially employed. Heat from both the product stream and SGG 46 are transferred to the exhaust stream and downstream after-treatment assembly. Port 48 and port 49 can allow for various sensing or other devices to be attached to SGG 46.

Optionally, SGG 46 can be configured so that at least a portion of the product stream can be supplied via a conduit to an external hydrogen- consuming device (not shown in FIGs. 4a or 4b), so that at least a portion of the product stream is directed away from plenum 42 and exhaust conduit 43. Also optionally, SGG 46 can be operated to produce and introduce the product stream into plenum 42 (or to an external device) without the flow of the exhaust stream (for example, when the engine is not operating).

[0045] When compared to employing an exhaust stream of an engine as the oxidant reactant for a fuel processor, employing an air stream (for example, supplied via a blower) can offer the advantages of increased and repeatable control of the reactant supply to, and operation of, the fuel processor substantially independently of the operation of the engine. The air stream can be supplied when desired, can comprise a nearly constant level of oxygen, at a desired flow rate and pressure, and at conditions that are substantially independent of the operating condition of the engine. Furthermore, employing an oxidant stream that is independent of the operating condition of the engine enables the fuel processor to be employed in engine system applications where the engine exhaust stream may not contain a sufficient level of oxygen including, for example, engines that operate with a near stoichiometric air-to-fuel ratio, or in applications where a product stream is desired also during times when the engine is not operating. Alternatives to a blower include supplying oxidant reactant to the fuel processor via an air compressor, a turbo-compressor, a supercharger, from a storage tank, or from the air intake subsystem of an engine.

[0046] Many exhaust after-treatment devices comprise catalysts and/or other materials for which the reaction or activity rates increase with increasing temperature. For example, the activity of certain oxidation catalysts increases substantially above about 150°C; and the NO_x conversion efficiency of a LNT typically increases substantially above about 250°C. Furthermore, it can be desirable to regenerate an exhaust after-treatment device at elevated temperatures. For example, the time desired to desulfate a lean NO_x trap (LNT) can decrease substantially above about 500°C; and the time desired to regenerate a particulate filter can decrease substantially above about 600°C.

Employing sensible heat released from a fuel processor as well as a hot product stream can advantageously increase the temperature of the exhaust stream and downstream exhaust after-treatment devices including, for example, during start-up or idle conditions of the engine, during operation of the engine system in cold environments and/or during a regeneration process of an exhaust after-treatment device. Utilizing sensible heat that would otherwise be released as waste heat into the atmosphere in a separately configured fuel processor, can offer the advantages of increasing the thermal efficiency, reducing the fuel penalty and/or reducing the volume of a fuel processor. The housing of the fuel processor can comprise devices and features that can increase the heat flux of the fuel processor or transfer of sensible heat from the fuel processor to the exhaust stream of the engine in the engine exhaust stream conduit. For example, the housing can comprise protruding fins that increase the surface area of the fuel processor that is in contact with the exhaust stream. Furthermore, the cooling effect of the exhaust gas stream as it transfers heat away from the fuel processor can beneficially reduce the requirement for an additional cooling system for the fuel processor, which can advantageously further reduce the complexity, cost, weight, volume and/or footprint of the fuel processor.

[0047] With the present approach, where the fuel processor is not reliant upon engine exhaust as the oxidant reaction stream, the fuel processor can be operated to produce a product stream substantially independently of the engine operation. For example, the fuel processor can be operated to produce a product stream and regenerate an exhaust after-treatment assembly while the engine is turned off. When the oxygen-containing engine exhaust stream is not flowing, a lesser amount of product stream from the fuel processor can create a fuel-rich condition desired for the regeneration process of the exhaust after-treatment assembly, resulting in advantageously reducing the fuel consumption for the regeneration process. A regeneration process for the exhaust after-treatment assembly can be programmed to occur prior to starting of the engine or after the engine has been turned off. In another example, the fuel processor can be operated to produce and introduce a product stream into an exhaust after-treatment assembly to heat the assembly if the exhaust after-treatment assembly is below a desired threshold temperature value or as a pre-programmed sequence of events including, for example, producing and introducing a product stream into the exhaust after-treatment assembly prior to and/or during the start of the engine to heat it up. The fuel processor can be operated to produce a syngas or flue gas product stream in order to heat the exhaust after-treatment assembly by reacting hydrogen in the product stream with catalyst in the exhaust after-treatment assembly and/or by transferring sensible heat from the product stream to the exhaust after-treatment assembly. Heating the exhaust after-treatment assembly when the exhaust after-treatment assembly is cold can advantageously reduce the levels of regulated emissions in the exhaust stream during a cold start of the engine or when the engine is operated in cold conditions. Once the engine is started, the attendant

advantages of heat transfer between the exhaust stream and the fuel processor accrue.

[0048] In preferred embodiments of the systems and methods described above, the fuel processor is a syngas generator that is a non- catalytic partial oxidation reformer that during normal operation is operated to produce a syngas or flue gas stream. However, the fuel processor integration into an engine system and the operating methods described herein can be implemented for various types of fuel processors including SGGs, reformers or other reactors used to produce hydrogen-containing gas streams. These can be of various types, for example, catalytic partial oxidizers, non-catalytic partial oxidizers, and/or autothermal reformers. Suitable reforming and/or water-gas shift catalyst can be employed in the fuel processor.

[0049] The fuel supplied to the fuel processor can be a liquid fuel (herein meaning a fuel that is a liquid when under International Union of Pure and Applied Chemistry (IUPAC) defined conditions of standard temperature and pressure) or a gaseous fuel. Suitable liquid fuels include, for example, diesel, gasoline, kerosene, liquefied natural gas (LNG), fuel oil, methanol, ethanol or other alcohol fuels, liquefied petroleum gas (LPG), or other liquid fuels from which hydrogen can be derived. Alternative gaseous fuels include natural gas and propane.

[0050] The fuel processor can be deployed in various end-use mobile or stationary engine system applications where a hydrogen- consuming device is employed and/or hot gas is needed. The product stream can be directed to one or more hydrogen-consuming devices for example an exhaust after-treatment device, a fuel cell, or a combustion engine.

[0051] In preferred embodiments of the systems and methods described above, the engine is a lean burn combustion engine.

However, the engine can be a near stoichiometric air-to-fuel ratio type engine. Suitable fuels supplied to the engine include, for example, diesel, gasoline, kerosene, liquefied natural gas (LNG), fuel oil, methanol, ethanol or other alcohol fuels, liquefied petroleum gas (LPG), jet, biofuel, natural gas or propane.

[0052] While particular elements, embodiments and applications of the present invention have been shown and described, it will be understood, that the invention is not limited thereto since

modifications can be made by those skilled in the art without departing from the scope of the present disclosure, particularly in light of the foregoing teachings.

Claims

What is claimed is:

1. An engine system comprising:

(a) an engine that during operation produces an exhaust

stream;

(b) an exhaust stream conduit connected to receive said

exhaust stream from said engine;

(c) an exhaust after-treatment assembly for at least

periodically reducing regulated emissions in said exhaust stream, and

(d) a fuel processor for producing a product stream, said fuel processor further comprising:

(i) a housing, and

(ii) an oxidant inlet conduit fluidly connected to

receive an air stream and a fuel inlet fluidly connected to receive a fuel stream,

wherein at least a portion of said housing is located within said exhaust stream conduit, and wherein said exhaust after- treatment assembly is located downstream of said fuel processor and is connected to selectively receive said product stream from said fuel processor.

2. The engine system of claim 1 wherein said housing is located entirely within said exhaust stream conduit.

3. The engine system of claim 1 or claim 2 wherein said air stream is supplied by a blower.

4. The engine system of any one of claims 1 to 3, said system further comprising a hydrogen-consuming device, wherein said fuel processor further comprises a product stream conduit to supply a hydrogen-containing product stream to said hydrogen consuming device.

5. The engine system of any one of claims 1 to 4, wherein said fuel processor is a non-catalytic fuel processor.

6. An engine system comprising an engine, an exhaust conduit and a fuel processor located within said exhaust conduit, said fuel processor comprising an interior reaction chamber, wherein said interior reaction chamber is fluidly connected to receive fuel from a fuel supply subsystem and an oxidant from an oxidant supply subsystem located external to said exhaust conduit.

7. The engine system of claim 6 wherein said oxidant supply subsystem is located external to said engine.

8. A method of operating an engine system comprising an engine, an exhaust after-treatment assembly, and a fuel processor comprising a housing and an interior reaction chamber, said method comprising: (a) operating said engine system to produce an engine exhaust stream;

(b) directing at least a portion of said engine exhaust stream to at least one exhaust after-treatment device in said exhaust after-treatment assembly, for reducing regulated emissions in said engine exhaust stream;

(c) introducing a fuel and an air stream into said interior reaction chamber of said fuel processor and operating said fuel processor to produce a product stream; and

(d) at least periodically introducing at least a portion of said product stream into said exhaust after-treatment device for heating or regenerating said exhaust after-treatment device,

wherein during operation of said engine at least a portion of said engine exhaust stream flows over at least a portion of said fuel processor housing.

9. The method of claim 8 wherein after said engine has been shut off, said fuel processor is operated to produce and introduce at least a portion of said product stream into said exhaust after- treatment assembly.

10. The method of claim 8 wherein, prior to starting operation of said engine, said fuel processor is operated to produce and introduce at least a portion of said product stream into said exhaust after-treatment assembly.

1 1. The method of claim 8 wherein during start-up of said engine, said fuel processor is operated to produce and introduce at least a portion of said product stream into said exhaust after-treatment assembly.

12. The method of claim 11 wherein said fuel processor is operated to produce and introduce at least a portion of said product stream into said exhaust after-treatment assembly when said exhaust after-treatment assembly is below a threshold temperature value.

13. The method of any one of claims 8 to 12 wherein said fuel processor is located within an exhaust conduit from said engine.

14. The method of any one of claims 8 to 13 wherein said fuel processor interior reaction chamber does not receive said engine exhaust stream from said exhaust conduit.

15. The method of any one of claims 8 to 14 wherein said product stream is introduced into a hydrogen-consuming device other than the exhaust after-treatment assembly.

16. The method of any one of claims 8 to 15 wherein said product stream is a hydrogen-containing gas stream.

17. The method of any one of claims 8 to 15 wherein said product stream is a flue gas stream.

18. The method of claim any one of claims 8 to 17 wherein said air stream is supplied by an air blower.