Priority Data [0001] The present application is a continuation-in-part of U.S. Patent Application Serial No. 10/213,890, filed August 6, 2002, published May I52003 as US 2003- 0079520 Al (pending), incorporated herein by reference. Field of the Application [0002] The present application relates to a method and apparatus for producing simulated alternative fuel exhaust using a non-engine based test system. Background [0003] Exhaust components, such as catalytic converters, are designed to treat exhaust produced when an internal combustion engine burns one or more specific fuel—typically gasoline or diesel fuel. Where the exhaust component will treat exhaust from the combustion of alternative fuel(s), the simulated exhaust must be produced by burning the alternative fuel(s). In order to produce a simulated alternative fuel exhaust using a bench engine, the bench engine generally must be modified to burn the alternative fuel. [0004] Apparatus and methods are needed to accurately and cost effectively produce simulated alternative fuel exhaust. Summary [0005] The present application provides a method for testing one or more test components. The method comprises: providing a non-engine based test system comprising a combustor in fluid communication with the one or more test components and supplying air and fuel to the combuslor al an air to fuel ratio (AFR) and under feed conditions effective to produce a feedstream flowpath. The fuel comprises one or more alternative fuel which is gaseous at ambient conditions comprising atmospheric pressure and a temperature of about 20° C or higher. Supplying air and fuel comprises feeding the one or more alternative fuel to a pressure regulator to produce one or more pressure regulated alternative fuel and feeding the one or more pressure regulated alternative fuel to the combustor. The method comprises combusting at least a portion of fuel in the feedstream flowpath under combustion conditions effective to produce an exhaust product comprising one or more alternative fuel exhaust, and exposing the one or more test components to the exhaust product under test conditions effective to produce one or more treated components. [0006] The application also provides a test system comprising a non-engine combustor in fluid communication with a fuel supplier, an air supplier, and a test component, the fuel supplier comprising one or more pressurized fuel container in fluid communication with one or more pressure regulator in fluid communication with the combustor. Brief Description of the Figures [0007] Figure 1 shows a schematic diagram of one embodiment of the system. [0008] Figure 2A is a drawing of a preferred embodiment of a burner suitable for use with the present application. [0009] Figure 2B is a close up view of the circled portion of the burner. [0010] Figures 3 A is a frontal view of a swirl plate which imparts the desired swirling motion to the air entering the combustion section of the burner. [0011] Figure 3 C is a rear view of the swirl plate of Figure 3 A. [0012] Figures 3B, 3D, and 3E are cross sections through the swirl plate of Figures 3 A and 3 C. [0013] Figure 4A is an exploded view of one embodiment of an air assisted fuel spray nozzle suitable for use in the apparatus. [0014] Figure 4B is a frontal view of the flanged end of the male fitting of the air assisted fuel spray nozzle of Figure 4 A illustrating an arrangement of air injection openings. [0015] Figure 4C is a frontal view of the opposed end of the air assisted fuel spray nozzle of Figure 4B. [0016] Figure 4D is an illustration of a preferred air assisted fuel spray nozzle. [0017] Figure 4E is a frontal view of the flanged end of the male fitting of the air assisted fuel spray nozzle of Figure 4D. [0018] Figure 4F is a frontal view of the opposed end of the air assisted fuel spray nozzle of Figure 4D. [0019] Figure 5 is a box diagram of a system for performing hot vibration testing. Brief Description [0020] Exhaust aftertreatment devices, such as catalytic converters, perform optimally when treating exhaust produced burning specific fuel(s). Bench engines typically burn gasoline or diesel fuel to produce simulated exhaust for that specific fuel. In order to burn a different fuel, the bench engine may need to be modified, for example, to supply an adapter for feeding a gaseous fuel. See U.S. Patent No. 5,713,336; 5,592,924; or 6,382,182, incorporated herein by reference. Other features of a bench engine that may require modification in order to burn alternative fuel(s) include but are not necessarily limited to spark timing, compression ratio, intake throttle, cooling, and engine structure itself. [0021] The use of a bench engine to burn one or more fuel(s) other than its target fuel may cause autoignition, coking and/or cracking prior to injection, poor atomization, vaporization, and/or mixing of the fuel. For example, fuels with low viscosities may not provide sufficient lubrication for the precision fit of fuel injection pumps or injector plungers, resulting in leakage or increased wear. Fuel atomization also is affected by fuel viscosity. [0022] The present application provides a non-engine based exhaust component rapid aging system (NEBECRAS) adapted to produce exhaust using one or more alternative fuels. Non-engine Based Exhaust Component Rapid Aging System [0023] An exemplary NEBECRAS is the FOCAS® rig. FOCAS® is a registered trademark of the Southwest Research Institute. The FOCAS® rig was developed to perform aging tests, i.e., to evaluate the long term effects of individual variables on the long term performance of a catalytic converter. The FOCAS® rig is capable of producing an exhaust product with a composition and temperature corresponding to that produced by the internal combustion engine of a motor vehicle burning the same fuel(s). [0024] The NEBECRAS, such as the burner system in the FOCAS® rig, can be used to supply the heat required to perform a variety of other tests, including, but not necessarily limited to design verification tests and durability tests. Although the FOCAS® rig, described in detail below, is a preferred NEBECRAS, it will be apparent to persons of ordinary skill in the art that any functional and effective NEBECRAS could be adapted for use in accordance with the principles described herein. [0025] The burner system in the FOCAS rig may be used to generate stoichiometric, rich, and lean hot gas conditions without substantial damage to the combustor. In a preferred embodiment, the combustor comprises a feed member comprising a swirl plate which is effective even at a stoichiometric air to fuel ratio (AFR) of producing a feedstream flowpath comprising an air shroud effective to prevent flame from attaching to a feed member during combustion of fuel. The feedstream flowpath also preferably prevents flame from remaining in constant contact with an inner wall of the combustor during combustion of fuel. [0026] Preferably, the NEBECRAS provides an oil free exhaust from combustion of gasoline or other fuel, such as gasoline; synthetic gasoline; diesel; liquefied fuel produced from coal, peat or similar materials; methanol; compressed natural gas; or liquefied petroleum gas. The NEBECRAS provides precise air to fuel ratio control, and preferably a separate oil atomization system for definitive isolation of the effects of fuel and of lubricant at various consumption rates and states of oxidation. The NEBECRAS preferably is capable of operating over a variety of conditions, allowing various modes of engine operation to be simulated, for example cold start, steady state stoichiometric, lean, rich, cyclic perturbation, etc. [0027] The FOCAS® rig may be deactivated, the system may be cooled to ambient conditions in a matter of minutes, and then immediately after cooling (if desired), the system can be used to perform additional testing. The FOCAS® rig offers improved repeatability and reduced cool down time. The FOCAS® rig also offers relatively easy maintenance compared to internal combustion engines, which require periodic maintenance (oil changes, tune-ups) and time consuming repairs. The FOCAS® rig is relatively simple (with less moving parts and friction areas) and can operate with improved fuel economy when operated lean. These advantages make it highly desirable as a research and development tool. [0028] In a preferred embodiment, the NEBECRAS comprises: (1) an air supply system to provide air for combustion to the burner, (2) a fuel system to provide fuel to the burner, (3) a burner system to combust the air and fuel mixture and provide the proper exhaust product constituents, (4) a heat exchanger to control the exhaust product temperature, and, (5) a computerized control system. In one embodiment, the NEBECRAS further comprises an oil injection system. -The Air Supply System [0029] Referring now to the drawings and initially to Figure 1 for purposes of illustration, a schematic diagram of a FOCAS® rig modified for use herein is shown. An air blower 30 draws ambient air through an inlet air filter 20 and exhausts a pressurized stream of air. The air blower 30 and the mass air flow sensor 50 may be of any conventional design which will be well known to a person of ordinary skill in the art. In a preferred embodiment the air blower 30 is an electric centrifugal blower, such as a Fuji Electric Model VFC404A Ring Blower, and the mass air flow sensor 50 is an automotive inlet air flow sensor such as a Bosh Model Number 0280214001 available from most retail automotive parts stores. The volume of air supplied is set by adjusting a bypass valve 40 to produce a desired flow rate of air, which is measured by a mass flow sensor 50. -The Fuel Supply System [0030] Figure 1 illustrates a standard FOCAS® rig (a preferred NEBECRAS) which has been modified to include an additional fuel container 400 for providing alternative fuel. The FOCAS® rig includes a standard automotive fuel pump 10 for pumping fuel through the fuel line 12 to an electronically actuated fuel control valve 14 then to the burner 60. A variety of burn ratios may be simulated, including but not necessarily limited to substantially continuous stoichiometric combustion of fuel, rich-burn (insufficient oxygen concentration to fully combust the fuel) and lean-burn (more oxygen than is required to fully combust the fuel). Under typical test conditions, the FOCAS® rig is programmable to produce exhaust that is passed directly to the exhaust component. If desired, the FOCAS® rig provides substantially continuous and effective stoichiometric combustion for 200 hours or more without the need for maintenance. In a preferred embodiment, the burner may run substantially continuously at stoichiometric for at least 1500 hours with minimal maintenance. [0031] In a preferred embodiment, the feed system is adapted to meter and supply at least one alternative fuel(s). At least one supplemental fuel container 400, preferably a pressure cylinder 400 is provided in fluid communication with the fuel injector. In one embodiment, the pressure cylinder 400 is adapted to maintain the alternative fuel at greater than atmospheric pressure, such as at a pressure effective to maintain the material contained in the pressure cylinder as a fluid other than a gas, such as a liquid. [0032] Although other types of control valves may be used, a preferred fuel control valve 14 is a solenoid valve that receives a pulse width modulated signal from the computer control system and regulates the flow of fuel to the burner in proportion to the pulse width. The electronically actuated solenoid valve 14 may be of a design which will operate with a pulse modulated signal which will be well known to a person of ordinary skill in the art. In a preferred embodiment the electronically actuated fuel control valve 14 is a Bosch frequency valve model number 0280 150 306-850 available from most retail automotive parts suppliers. From the fuel control valve IA the fuel is piped to the air assisted fuel spray nozzle 16 in the burner assembly (described below). [0033] In one embodiment, the NEBECRAS burns only gaseous fuel. In this embodiment, the fuel pump 10 and liquid fuel supply is replaced by a high pressure cylinder 400, a high pressure fuel line 402, the pressure regulator 404, and a reduced pressure fuel line 406 which feeds directly to the fuel injector 16. [0034] In a preferred embodiment, the NEBECRAS comprises more than one fuel container, with at least one fuel container comprising a pressure cylinder adapted to deliver a gaseous feed. In this embodiment, the NEBECRAS is adapted to burn alternative fuel and/or liquid fuel. The pressure container preferably communicates with the combustor via a pressure regulator and is suitable to deliver either gas or compressed gas to the combustor. In this embodiment, the NEBECRAS includes the fuel pump 10 and the liquid fuel supply. The reduced pressure fuel line 406 fluidly communicates with the fuel line 12 downstream of the fuel pump 10. The fuel, whether reduced pressure alternative fuel, liquid fuel, or a combination thereof, flows through the fuel line 12 to the fuel injector 16. [0035] The operation of the NEBECRAS using an alternative fuel will be described with reference to compressed natural gas (CNG). However, the description also is applicable to other alternative fuels. Where the alternative fuel is CNG, the high pressure cylinder 400 is adapted to maintain the CNG at a pressure of from about 2400 to about 3600 psi. The CNG travels from the high pressure cylinder 400 through the high pressure fuel line 402 to a pressure regulator 404. Although it is preferred to provide a pressure regulator, a pressure regulator is not required to feed uncompressed gaseous material. Where the alternative fuel is compressed, as with CNG, the pressure is reduced, preferably to a reduced pressure of about 60-70 psi or less. The reduced pressure alternative fuel travels through a reduced pressure line 406 to a fuel line 12. -The Burner [0036] The burner is specially fabricated, as described below to produce stoichiometric combustion of the fuel and air. In a preferred embodiment, the burner 60 is a swirl stabilized burner capable of producing continuous stoichiometric combustion of automotive fuel. [0037] Referring now to Figure 2, in a preferred embodiment the burner comprises a plenum chamber 200 and a combustion tube 210. A swirl plate 18 separates the plenum chamber 200 from the combustion tube 210. The combustion tube 210 is constructed of material capable of withstanding extremely high temperatures. Preferred materials include, but are not necessarily limited to INCONEL or stainless steel, and optionally can be equipped with a quartz tube in place of the INCONEL tube for visual observation of the resulting flame pattern. [0038] The air and fuel are separately introduced into the burner 60. Air from the mass flow sensor 50 is ducted to the plenum chamber 200 (Fig. 2) then through the swirl plate 18 into the burner tube. The swirl plate 18 is equipped with a fuel injector 16. -The Fuel injector [0039] In a first embodiment, an air assisted fuel spray nozzle 16 is engaged using conventional means at the center of the swirl plate 18 inside of the plenum chamber 200 (Fig. 2). Fuel from the fuel supply line 14 is fed to the air assist fuel spray nozzle 16, where it is mixed with compressed air from air line 15 and sprayed into the combustion tube 210 (Fig.2). The compressed air line 15 provides high pressure air to assist in fuel atomization. [0040] Fig. 4A is one embodiment of the air assisted fuel spray nozzle 16. As seen from Fig. 4A5 the air assisted fuel spray nozzle 16 comprises male and female flanged fittings which are engaged with the swirl plate 18. A variety of suitable methods of engagement are known to persons of ordinary skill in the art. The female fitting 250 has a flanged end 252 and a substantially tubular extension 251. A male fitting 254 comprises a flanged end 256 and a substantially cylindrical extension 253 having an opposed end 268. The cylindrical extension fits within the tubular extension of the female fitting along its length. In a preferred embodiment, the clearance 270 between the inner wall 259 of the tubular extension 251 and the outer wall 263 of the tubular extension 253 is preferably about 1/8." The clearance creates a circumferential groove 257 for injection of fuel, which communicates with the fuel injection hole 264. [0041] Air injection bores 262 (preferably about 1/16") extend through the flanged end 256 and substantially parallel to the axis of the tubular extension 253 of the male fitting to a bore 260, which interfaces with the swirl plate 18. Fuel injection bores 264 extend from the outer wall 263 adjacent to the air injection bores 262 and radially inward. The air injection bores 262 are engaged with the air line 15 in any suitable manner. The fuel injection bores 264 are engaged with the fuel line 12 in any suitable manner. [0042] Fig. 4B is a frontal view of the flanged end 254 of the male fitting illustrating an arrangement of air injection bores 262. As seen in Fig. 4B, five air injection bores 262a-d and 265 are arranged similar to the numeral "5" on a game die. Specifically, a line drawn through the center of the central air hole 265 and through the center of any one of the corner air holes 262 a-d will have 45° angle when compared to a line drawn along 5x-5x in Fig. 4B. In other words, the center of the corner air holes 262a-d are found at the four corners of a square drawn around the central air hole 265. [0043] A frontal view of the opposed end of all parts of the air assist nozzle 16 when engaged is shown in Fig. 4C. In this "bulls-eye" view: the inner circle is the bore 260 of the female fitting; the next concentric ring is the opposed end 268 of the tubular extension 253 of the male fitting; the next concentric ring is the annular groove 270 formed by the clearance between the tubular extension 251 of the female fitting and the extension 253 of the male fitting; and, the outermost ring is the flange 252 defining a port 255. [0044] In a preferred embodiment of the fuel injector 16 (Fig. 4D-F), like parts are given like numbering as in Figs. 4A-4C. Referring to Fig. 4D, the air injection bores 262 are angled to direct the fuel into the air shroud for mixing and protection, while shearing the fuel fed through fuel injection bores 264 with injected air that passes directly through the fuel jet. The fuel injection bores 264 preferably are pointed directly into the air shroud for mixing and protection. The injection angles maximize fuel atomization within the space requirements and work with the swirl plate 18. The air assisted fuel spray nozzle 16 is engaged using conventional means at the center of the swirl plate 18. The air assisted fuel spray nozzle 16 comprises a flanged male fitting 252 adapted to mate with the a central bore 244 (Fig. 3C) in the swirl plate 18. In a preferred embodiment, the concentric clearance 270 between the outer wall 254a of the air assisted spray nozzle and the wall 281 of the central bore of the swirl plate 18 is preferably from about 0.2" to about 0.75", most preferably about 0.25". The air assisted fuel spray nozzle 16 defines air injection bores 262 having a longitudinal axis represented by line Y-Y'. Line Y-Y' forms angles x, x' relative to line 5F-5F, drawn along the inner wall 280 of the swirl plate. The angles x, x' preferably are from about 65° to about 80°, preferably about 76°. The air injection bores 262 may have substantially any configuration. In a preferred configuration, the air injection bores 262 are cylindrical bores. [0045] The air injection bores 262 extend from a supply end 298 to an injection end 299, and have an inner diameter effective to permit a suitable flow of fuel. In a preferred embodiment, the air injection bores 262 have an inner diameter of from about 0.060" to about 0.080", preferably about 0.070". The air injection bores 262 extend from supply end 298 to the combustion tube 210 (Fig. 2) on the injection end 299. [0046] The air assisted fuel spray nozzle 16 comprises a first flanged end 252a adapted to mate with the outer wall 282 of the swirl plate 18. The alignment of the first flanged end 252a and the outer wall 282 may take a number of configurations, such as complimentary grooves, complimentary angles, or other types of mated machine fittings. In a preferred embodiment, the first flanged end 252a and the outer wall 282 are substantially flat and parallel to one another, abutting one another along a line substantially perpendicular to longitudinal axis A-B. In a preferred embodiment, the first flanged end 252a extends radially outward from the longitudinal axis, illustrated by line A-B, to a distance of from about 0.38" to about 0.65", preferably to a distance of about 0.38" therefrom. [0047] A second flanged end is not entirely necessary; however, in a preferred embodiment, the air assisted spray nozzle 16 further comprises a second flanged end 252b extending radially outward from the longitudinal axis defined by line A-B to a distance of from about 0.3" to about 0.45", preferably about 0.38" therefrom. [0048] As shown in Fig. 4D, the first flanged end 252a and the second flanged end 252b define a flow chamber 297 comprising a port 255 at the supply end 298. The configuration and size of this port 255 is not critical provided that the port 255 permits the flow of an adequate amount of fuel through the flow chamber 297 to the fuel injection bores 264 defined by the air assisted spray nozzle 16. The injection end 299 of the air assisted spray nozzle 16 defines the fuel injection bores 264, which extend from the flow chamber 297 to an opening 291 in the air injection bores 262. [0049] The fuel injection bores 264 may have substantially any configuration as long as they deliver an adequate flow of fuel. The fuel injection bores 264 have a longitudinal axis represented by the line R-R', which forms angles z, z' relative to the line 5F-5F. In a preferred embodiment, the fuel injection bores 264 are cylindrical and have a diameter of from about 0.020" to about 0.040", preferably about 0.031". Preferably, angles z,z' are from about 60° to about 80°, preferably about 73°. [0050] In operation, fuel flows through the port 255, through the flow chamber 297, and through the fuel injection bores 264 and opening 291, and is injected into the air injection bores 262, which results in a concurrent injection of air and fuel at the injection end 299 of the air assisted fuel spray nozzle 16. Fuel collides with air at opening 291, resulting in flow jets effective to collide with the air shroud. Materials of construction and dimensions for all components of spray nozzle 16 will vary based on the process operating conditions. [0051] As shown in Fig. 4E, the air injection bores 262 comprise openings 262a-d at the injection end 299 which are arranged like the numeral "4" on a game die. The openings 262 a-d preferably are spaced at approximately 90° angles relative to one another, as illustrated by AB and A'B'. [0052] Fig. 4F is a frontal view of the supply end 298 of the air assisted fuel spray nozzle 16. In this "bulls-eye" view: the inner circle is the bore 260 and the remaining concentric rings comprise the outer face 261 of the second flanged end 252b. Fuel flows from the fuel line 12 to the spray nozzle 16 through the port 255, into the fuel flow chamber 297 and through the fuel injection bores 264 to the air injection bores 262. -The Swirl plate [0053] In a preferred embodiment the swirl plate 18 is capable of producing highly turbulent swirling combustion, as shown in Figures 3 A-E so as to provide a complex pattern of collapsed conical and swirl flow in the combustion area. The flow pattern created by the swirl plate 18 involves the interaction of a number of swirl jets 242 and 242a-c, 253 and 253a-c and turbulent jets 248 and 248a-c, 249 and 249a-c, and 250 and 250a-c. The interaction of these jets creates a swirling flow that collapses and expands, preferably at intervals that are substantially equivalent in length to the inner diameter of the combustion tube 210. In a preferred embodiment, the inner diameter of the combustion tube 210 is 4 inches, and the intervals at which the swirling flow collapses and expands is every 4 inches. The pattern clearly defines flow paths along the wall of the combustion tube 210, which define the location of the igniters 220 along the combustion tube 210. In the embodiment described herein, the igniters are located at the first and second full expansions along the path of inner swirl jets (253 a,b,c). [0054] In a preferred embodiment, shown in Figures 3 A-3E, the swirl plate 18 is a substantially circular disc having a thickness sufficient to fix the air flow pattern and to create an "air shroud" that is effective to protect the fuel injector. The thickness generally is about 1A inch or more. The swirl plate 18 has a central bore 255. The air assisted spray nozzle 16 is fitted to the swirl plate 18 at this central bore 255 using suitable means. In the described embodiment, the swirl plate 18 has bores 240 therethrough for attachment of the air assisted spray nozzle 16. The swirl plate 18 is made of substantially any material capable of withstanding high temperature, a preferred material being stainless steel. [0055] The central bore 255 is defined by a wall 244. Generally speaking, each type of jet located at a given radial distance from the longitudinal axis of the swirl plate has four members (sometimes called a "set" of jets) spaced apart at approximately 90° along a concentric circle at a given distance from the central bore 255. Three sets of turbulent jets 248, 249, and 250 direct the air toward the central bore 255. The inner and outer sets of swirl jets 242, 253, respectively, direct the air from the outer circumference 256 of the swirl plate 18 and substantially parallel to a line 3C-3C or 4E-4E (Fig. 3C) through the diameter the swirl plate in the respective quadrant in the direction of the burner. [0056] The precise dimensions and angular orientation of the jets will vary depending upon the inner diameter of the burner, which in the embodiment described herein is about 4 inches. Given the description herein, persons of ordinary skill in the art will be able to adapt a swirl plate for use with a burner having different dimensions. [0057] The orientation of the jets is described with respect to the front face of the swirl plate 257, with respect to the longitudinal axis 241 of the swirl plate 18, and with respect to the lines 3C-3C and 4E-4E in Fig. 3C, which divide the swirl plate 18 into four quadrants. Six concentric circles 244 and 244 a-e (Fig 3C) are depicted, beginning at the interior with the wall 244 defining the central bore 255 and extending concentrically to the outer circumference 244e of the swirl plate 18. In the embodiment described herein, the central bore has an inner diameter of 1.25 inches, or an inner radius of 0.625 inches. A first concentric circle 244a is 0.0795 inches from the wall 244; a second concentric circle 244b is 0.5625 inches from the wall 244; a third concentric circle 244c is 1.125 inches from the wall 244; a fourth concentric circle 244d is 1.3125 inches from the wall 244; and, a fifth concentric circle 244e is 1.4375 inches from the wall 244. [0058] A set of outer swirl jets are labeled 242, and 242a,b,c. A set of inner swirl jets are labeled 253 and 253 a,b,c. The outer swirl jets 242 and 242a-c and the inner swirl jets 253 and 253 a-c have the same angle z (Fig. 3B) relative to the surface 257 of the swirl plate 18, preferably an angle of 25°. In a preferred embodiment, both the outer swirl jets 242 and 242a-c and the inner swirl jets 253 and 253a-c have an inner diameter of 5/16." The outer swirl jets 242 direct air from an entry point 242x along the outer circumference 256 of the swirl plate 18 on the fuel injection side 59 to an exit point 242y along circle 244b on the burner side 60. The longitudinal axis of the outer swirl jets 242 is parallel to and spaced 0.44 inches from lines 3C-3C and 4E-4E in their respective quadrants. The inner swirl jets 253 extend from an entry point along the circle 244b on the fuel injection side 59 to an exit point on the burner side 60 along the central bore 244. The longitudinal axis of the inner swirl jets 253 also is parallel to lines 3C-3C and 4E-4E in the respective quadrants. [0059] The air shroud jets 250 direct air from a point along the circle 244b directly inward toward the center of the central bore 255. The longitudinal axis of the air shroud jets 250 runs along the lines (3C-3C and 4E-4E). The angle a (Fig. 3D) of the longitudinal axis 251 of the air shroud jets 250 with respect to the longitudinal axis 241 of the swirl plate 18 is 43.5°. The air shroud jets 250 preferably have an inner diameter of about 1A inch. The exit points 242y of the outer swirl jets 242 on the burner side 60 of the swirl plate 18 preferably are aligned longitudinally, or in a direction parallel to the longitudinal axis 241 of the swirl plate, with the entry points of the air shroud jets 250 on the fuel injection side 59 of the swirl plate 18. [0060] The air shroud jets 250 are primarily responsible for preventing the flame from contacting the air assisted spray nozzle 16. The air flowing from the air shroud jets 250 converges at a location in front of the fuel injector 16 (Figs. 1 and 2) and creates a conical shroud of air which results in a low pressure area on the fuel injection side 59 (Fig. 1) of the swirl plate 18 and a high pressure area on the burner side 60 of the swirl plate 18. The low pressure area on the fuel injection side 59 helps to draw the fuel into the combustion tube 210 while the high pressure area on the burner side 60 prevents the burner flame from attaching to the face of the air assisted spray nozzle 16, and prevents coking and overheating of the nozzle 16. In a preferred embodiment, the air shroud jets 250 converge from about 0.5 cm to about 1 cm in front of the nozzle 16. [0061] The combustion tube 210 is equipped with several spark igniters 220 (see Figure 2). In a preferred embodiment, three substantially equally spaced igniters 220 are located around the circumference of the combustion tube in the gas "swirl path" created by the swirl plate 18. In a preferred embodiment these igniters 220 are marine spark plugs. [0062 J In an alternate embodiment, suitable for combustion of low volatility fuels, the combustion tube 210 is further equipped with ceramic foam located about one foot downstream from the spray nozzle 16. Substantially any suitable foam may be used, preferably 10 pore/inch SiC ceramic foam commercially available, for example, from Ultra-Met Corporation, Pacoima, CA 91331. -Interaction of fuel injector and swirl plate [0063] The burner 60 and the fuel injector 16 work together to provide substantially continuous and "effective stoichiometric combustion." As used herein, the term "effective stoichiometric combustion" refers to stoichiometric combustion which maintains the integrity of the wall of the combustion tube without substantial coking of the fuel injector. As a result, the burner may run substantially continuously at stoichiometric for at least 200 hours without the need for maintenance. In a preferred embodiment, the burner may run substantially continuously at stoichiometric for at least 1500 hours with minimal maintenance. By minimal maintenance is meant spark plug changes only. [0064] The design of the fuel injector 16 (above) takes into account the primary features of the swirl plate 18, namely: [0065] 1 ) The outer turbulent jets 248 and 249 (shown in Section 3C-3C) keep the flame from remaining in constant contact with the interior wall of the combustor tube 210. Because the burner 60 operates continuously, and for extended times at stoichiometric (the hottest air/fuel ratio operating point), it is necessary to maintain the integrity of the wall of the combustion tube 210. Currently, the INCONEL combustion tube 210 lias been exposed to over 1500 hours of operation, without showing evidence of deterioration. This feature does not substantially affect fuel injection. [0066] (2) The inner swirl jets 242 set-up the overall swirl pattern in the burner. Air exiting the inner swirl jets 242 impacts the interior wall of the combustor tube 210 about 3 inches downstream of the swirl plate 18, and directly interacts with the spray of fuel from the fuel injector 16. [0067] (3) The inner turbulent jets 250, are sometimes referred to as the 'air shroud' jets. Air exiting the inner turbulent jets 250 converges 0.75 inches in front of the fuel injector 16. This feature provides two very important functions. The point of convergence creates a high pressure point in the burner 60, which prevents the burner flame from attaching to the fuel injector 16 (preventing coking). The second function, which interacts directly with fuel injection and impacts flame quality, is that it shears the remaining large fuel droplets as they enter the burner flame. [0068] The exhaust from the burner 60 is routed to a heat exchanger 70. The heat exchanger 70 may be of any conventional design which will be well known to a person of ordinary skill in the art. The exhaust product is next routed to an optional oil injection section 110 (Fig. 1). The oil injection section provides an atomized oil spray comprising oil droplets with a sufficiently small diameter to vaporize and oxidize the oil before it reaches the catalyst. The oil injection system may be located anywhere downstream from the burner. [0069] A data acquisition and control system suitable for use with the NEBECRAS is provided. The system preferably provides a means to control ignition, air assist to the fuel injector, auxiliary air, fuel feed, blower air feed, oil injection, etc. (discussed more folly below). An example of a suitable control system would be a proportional integral derivative (PID) control loop, for example, for controlling fuel metering. [0070] The NEBECRAS data acquisition and control software controls test parameters simultaneously throughout operation, and is programmable to simulate any desired set of test conditions. In a preferred embodiment the data acquisition and control system is also capable of controlling a number of parameters, including controlling the lube oil injection and burner systems. The software program uses measured data to calculate total exhaust flow and burner air to fuel ratio, and to check conditions indicative of a system malfunction. The burner air to fuel ratio may be controlled as either open or closed loop, maintaining either specified fuel flow or specified air to fuel ratio. Air to fuel ratio control is achieved by varying the rate of fuel delivered to the burner (modifying the pulse duty cycle of a fixed frequency control waveform). Open loop control can be activated allowing the operator to enter a fixed fuel injector pulse duty cycle. Closed loop control can be activated in which the actual burner air to fuel ratio is measured and compared to the measured value of the air to fuel setpoint and then adjusting the fuel injector duty cycle to correct for the measured error. The front panel of the program is used to allow the user to input a preferred test cycle, and to run the test using a single screen. Alternative Fuel(s) and Testing Using Alternative Fuels [0071] The FOCAS® rig or other NEBECRAS preferably uses an air atomized, orifice type injector, which can inject a variety of fuels. Substantially any test may be run using exhaust gas produced using alternative fuel(s) or a combination of alternative fuel(s) and liquid fuel(s). Examples of such tests include, but are not necessarily limited to aging, cold start simulation, drive cycle simulation, air-fuel ratio sweeps, light off tests, vibration tests, temperature profile tests, thermal stress tests, quench tests, shell deformation tests, and thermal cycle tests. The test conditions for the foregoing types of tests are described in more detail below. In order to perform such tests, the NEBECRAS generally is installed in place of a bench engine in a known test rig. [0072] The NEBECRAS may be used to perform various tests on substantially any component. Preferred components are automotive components, preferably vehicle exhaust system components. A preferred component is a catalytic converter. Other such components include, but are not necessarily limited to EGR valves, EGR coolers, oxygen sensors, exhaust tubing, mufflers, turbochargers, and exhaust manifolds. [0073] The FOCAS® rig is designed to burn gasoline (a liquid fuel) to produce exhaust gas. However, the FOCAS® rig also may be used to burn one or more alternative fuels, or a combination of alternative fuels, alone, or in combination with one or more liquid fuel(s) including, but not necessarily limited to gasoline and diesel fuel. [0074] For purposes of the present application, the phrase "alternative fuels" refers to fuels which are gaseous at atmospheric pressure and at typical ambient temperatures. Atmospheric pressure is understood to be about 101.33 kilopascals and ambient temperature generally is from about 20° C to about 25 0C. "Alternative fuels" include, but are not necessarily limited to fuels in gaseous form and fuels in compressed gaseous form. Examples of alternative fuels include, but are not necessarily limited to natural gas, methane, ethane, propane, refinery gas, butane, natural gas liquid(s) (NGL), including but not necessarily limited to liquefied 00

petroleum gas (LPG), liquified natural gas (LNG), compressed natural gas (CNG), and renewable fuels. [0075] Refinery gas is a mixture of hydrocarbon gases (and often some sulfur compounds) produced in large-scale cracking and refining of petroleum, and typically comprises a mixture of several of hydrogen, methane, ethane, propane, butanes, pentanes, ethylene, propylene, butenes, pentenes, and small amounts of other components, such as butadiene. [0076] A typical composition of CNG is: (Typical Composition of CNG (% Volume) Methane I 91.9 Ethane [Carbon Dioxide 2.0 Propane 1-2 i-Butane 0.4 i-Pentane 0.2 Nitrogen j 0.2 n-Butane ! o.i

[0077] Natural gas liquids (NGL 's) include, but are not necessarily limited to natural gasoline, typically comprising ethane or pentane and heavier components of the natural gas stream. LPG' s are a subcategory of NGL' s that are produced along with and extracted from natural gas. LPG's also are produced from the refining of crude oil. Commercial LPG generally comprise propane, butane, and butane-propane mixtures. Accelerated aging tests-"Rat-A Cycle Conditions" [0078] The method and apparatus herein is useful for accelerated aging using one or more alternative fuel(s). Thermal aging of a catalytic converter can be efficiently accelerated because the rate at which thermal deactivation of a catalytic converter occurs can be increased by operating at higher catalyst temperature. "Accelerated aging conditions" generally involve combinations of elevated catalyst inlet temperatures, chemical reaction-induced thermal excursions (simulating misfire events), and average air/fuel ratio's (AFR' s) effective to accelerate aging of a test component. The "RAT-A cycle" refers to the combination of conditions in the General Motors "Rapid Aging Test Cycle." One hundred hours of aging on the GM RAT-A cycle is generally understood to demonstrate a level of durability. [0079] The RAT-A cycle is characterized mainly by steady-state, stoichiometric operation with short thermal excursions. The thermal excursions are created by operating rich, to generate about 3 percent carbon monoxide (CO), while injecting secondary air (about 3 percent oxygen, O2) in front of the catalyst. The excess reductants and oxidants react in the catalyst, releasing the chemical energy in the form of heat. The catalyst inlet temperature and exhaust gas flow rates are also used to specify the test cycle setup. The flow is specified in standard cubic feet per minute (scfm), typically 75 scfm. C. Webb and B. Bykowski, "Development of a Methodology to Separate Thermal from Oil Aging of a Catalyst Using a Gasoline- Fueled Burner System" SAE 2003-01-0663, incorporated herein by reference. [0080] On the engine, adjusting engine speed sets up the flow specification. The gas temperature at the inlet to the catalyst is achieved by adjusting engine load (throttle position) during the steady-state, stoichiometric portion of the cycle. The thermal excursion is created by adjusting engine operating AFR during the rich

portion of the cycle, and adjusting air injection to achieve the 3 percent CO and Q?

specification. The table (below) provides the setup conditions for the cycle. It

should be noted that the catalyst inlet temperature is specified during the

stoichiometric portion of the cycle, but that the exhaust gas concentrations to create

the exotherm (and not catalyst inlet temperature) are specified during the thermal

excursion portion of the cycle. The two specifications create a thermal profile within

the catalyst.

Aging Cycle Specifications:

-Drive Cycle Simulation Tests "FTP-75 Conditions" [0031] The method and apparatus also is useful to perform drive cycle tests using one or more alternative fuels. During drive cycle conditions, all of the following conditions are varied to simulate actual driving: exhaust flowrate, exhaust gas temperature, and exhaust gas stoichiometry. FTP-75 conditions include: 1) varying the exhaust flowrate, preferably in the range of from 0 to about 200 standard cubic feet per minute (scfm), to simulate the exhaust flowrates of the test vehicle throughout the FTP; 2) varying the exhaust gas temperature, preferably in the range of from about 20 to about 900 0C, to simulate the exhaust gas temperatures at the catalyst inlet throughout the FTP; and, 3) varying the exhaust gas stoichiometry, preferably in the range of from about 10 to about 40 AFR, more preferably from about 10 to about 20 AFR, to simulate the exhaust gas stoichiometry of the vehicle throughout the FTP. The system exhaust gas mixture ideally contains similar concentrations of hydrocarbons, carbon monoxide, and oxides of nitrogen as seen in the vehicle exhaust at any time during the FTP test. Simulated Cold-Start [0082] The system also is useful to perform simulated cold-start using alternative fuel(s). To perform the simulated cold-start, the test component preferably is a catalytic converter, and the catalyst is at a temperature sufficiently low to simulate cold start. Suitable temperatures are 100 0C or less. Preferably, the simulation either is begun with the catalyst at a bed temperature of about 700C or less, preferably less than 70 0C, or is cooled to such a temperature using any suitable cooling arrangement known to persons of ordinary skill in the art. In a preferred embodiment, the catalyst is cooled using an air blower. In order to efficiently cool the catalyst using an air blower, the air blower is set at an initial flow rate effective to cool the catalyst to the desired temperature within a reasonable period of time. Preferably, the air blower is set at an initial flow rate of 40 standard cubic feet per minute (scfm) or more, more preferably 50 scfm. The air flow is directed onto the catalyst until the desired temperature is reached. [0083] With the burner off and the blower on, raw oil is injected from about 2 to about 15 seconds, preferably about 4 seconds. The burner is then lit, and preferably programmed into a rich warm-up mode. A rich warm-up mode for most engine types is an aiπfuel ratio (AFR) of from about 9:1 to about 14:1, preferably about 13.75:1. Thereafter, oil injection is continued for a period of time effective to simulate the flow of lubricating oil to the catalytic converter upon cold start of the given engine type, preferably about 20 seconds or more, more preferably about 22 seconds. Thereafter, oil injection is halted and the rich warm-up mode is continued for a period of time effective to prevent excess build-up of unburned oil on the face of the catalyst, preferably for about 20 seconds or more, more preferably for about 60 seconds. The targeted oil injection rate during the cold start simulation is from about 10 to about 40 grams/hour, preferably from about 28 to about 30 grams/hour. The cycle preferably is repeated a sufficient number of times to simulate the effect of cold start aging. In a preferred embodiment, the number of cycles is from about 1 to about 60,000, preferably from about 35,000 to about 40,000. [0084] If the catalyst is in a cool state (preferably 70 0C or less), then it is not necessary to cool the catalyst. However, if the catalyst is at a higher temperature, the catalyst is cooled before initiating cold start simulation. In order to accomplish this cooling, the air blower suitably is set at an initial flow rate of 40 scfin or more, preferably 50 scfm, until the catalyst is cooled to about 70 °C or less. Once the catalyst is at the desired initial temperature, preferably about 70 0C or less, oil is injected into the blowing air for several seconds. The oil injection system control can be programmed into the computer. The system also can be programmed to inject more or less oil, depending upon the system to be simulated. The targeted oil injection rate in the cold start simulation procedure is from about 10 to about 40 grams/hour, preferably from about 28 to about 30 grams/hour. [0085] After the burner is lit, oil injection at the targeted oil injection rate is continued for about 20 seconds or more, preferably for about 22 seconds, while a fuel rich mode is simulated. Thereafter, oil injection is halted. [0086] The burner is lit after the initial, relatively cool oil injection sequence of several seconds. The burner preferably is programmed into a fuel rich mode. A fuel rich mode generally comprises an AFR of 12.5: 1 or more, preferably 13.75: 1. After the burner is lit, oil injection is continued for about 20 seconds or more, preferably 22 seconds. Thereafter, oil injection is halted and the fuel rich mode is permitted to continue for a period of time effective to prevent excess build-up of unburned oil on the face of the catalyst. The fuel rich mode generally is continued for a period of time of about 20 seconds or more, preferably for about 60 seconds. [0087] During cold start simulations, the spark igniters are activated after the initial "cold" injection of raw lubricating oil is complete. The computer can be programmed to assure proper ignition time substantially immediately after the initial oil injection flow of from about 2 to about 15 seconds, preferably about 4 seconds. Once lit, the burner 60 and the fuel injector 16 work together to provide substantially continuous and effective stoichiometric combustion. Other Tests [0088] The NEBECRAS also may be used to perform other tests using alterative fuel(s). Such tests generally comprise: (a) varying one or more operating condition selected from the group consisting of temperature, time interval between changes in temperature, air- fuel ratio, and combinations thereof; and, (b) varying one or more other conditions while maintaining substantially constant one or more operating conditions selected from the group consisting of temperature, air-fuel ratio, and combinations thereof. The following is a specific description of a number of tests falling in categories (a) and (b). The description is illustrative only, and should not be construed as limiting the claims to preferred embodiments: a) Varying an operating condition selected from the group consisting of temperature, time interval between changes in temperature, air- fuel ratio, and a combination thereof: [0089] Tests in category (a) include, but are not necessarily limited to design verification tests, including durability tests. Such tests may comprise one or more different parameter compared to accelerated aging and drive cycle testing. Examples of a "different parameter" include, but are not necessarily limited to parameters selected from the group consisting of reduced maximum temperature, shorter intervals between temperature cycles, enhanced magnitude temperature cycling, multiple repetitions of the foregoing types of cycling, and combinations thereof. In a preferred embodiment, the reduced maximum temperature is 850 0C or less, preferably 500 0C or less. [0090] Specific examples of tests in category (a) include, but are not necessarily limited to shell deformation testing, temperature profile testing, thermal cycling, light- off testing, and air-fuel ratio sweeps. The foregoing tests are described in more detail below: -Shell Deformation Testing [0091] A catalytic converter generally is constructed such that a catalyst carrier is encased within a shell. The monolithic catalyst carrier generally is formed of ceramic, which is brittle and tends to be readily damaged. In order to prevent damage, the catalyst generally is elastically supported within the shell. [0092] The present application provides a method for evaluating the tendency of the shell to expand, generally called shell deformation tests, using a non-engine based test system operated using one or more alternative fuel(s). In a shell deformation test, a catalytic converter (330 in Fig. 1) comprising a container in fluid communication with the hot exhaust gas generated by the NEBECRAS, preferably a FOCAS® rig, is exposed to several heat-up and cool-down periods. In other words, the alternate stress conditions comprise exposing the component to exhaust gas at a first temperature for a first period of time and exposing the component to exhaust gas at a second temperature for a second period of time. The first temperature is sufficiently different than the second temperature to evaluate the dynamic and permanent response of the component (preferably comprising a catalytic converter and shell) to the first and second temperature. -Temperature Profile Testing [0093] Temperature profile testing entails exposing the component(s) to high- temperature (steady-state) step increases, preferably under steady AFR and flow rate conditions, in order to acquire internal (catalyst) and external (can surface) thermal gradient information. The alternate conditions generally comprise incrementally increasing the temperature of the exhaust product to produce the thermal gradient conditions, although the temperature also may be incrementally decreased. In other words, the catalytic converter is exposed to exhaust product comprising alternative fuel exhaust at a first temperature for a first period of time, then at a second temperature for a second period of time, then at a third temperature for a third period of time, and so on. The component is evaluated using known methods to determine the external and internal impact of exposure to the resulting thermal gradient. -Thermal Cycling [0094] The present application also uses a NEBECRAS to generate exhaust product comprising alternative fuel exhaust for thermal cycling tests. [0095] Thermal cycling severely stresses the test component by rapidly and repeatedly changing the test component temperature. The test component, preferably a catalytic converter, is exposed to exhaust product comprising alternative fuel exhaust at a first temperature for a first period of time, and then at a second temperature for a second period of time, and so forth. The first temperature and the second temperature are sufficiently different to thermally stress the component. [0096] Thermal cycling also tests the durability of a monolithic catalyst when exposed to exhaust product comprising alternative fuel exhaust. Conventional ceramic monolithic catalysts generally consist of a ceramic support with a coating upon which the catalyst is actually deposited. In order to obtain substantial density and strength, the ceramic material normally must be fired at a high temperature. Such high-temperature firing necessarily sinters the ceramic material, producing a very small surface area. Consequently, the ceramic must be coated with another material having a higher surface area, as well as specific chemical characteristics required for deposit of the catalyst. The high surface area coating or "washcoat" and the underlying ceramic material generally have different thermal expansion coefficients. When the component is exposed to the foregoing thermal cycling, the high surface area coating may tend to flake off of the underlying ceramic support. Air-Fuel Ratio Sweeps [0097] The application provides a method in which a NEBECRAS is used as the exhaust gas generator and heat source during air-fuel ratio sweeps using alternative fuel(s). In order to assess catalytic conversion at different AFR's, exhaust components are measured while the AFR is adjusted from lean to rich (or vice versa). In stepped AFR sweep tests, each AFR is maintained until steady-state operation is achieved. In continuous AFR sweep tests, AFR is continuously adjusted at a predetermined rate. (b) Varying one or more other conditions while maintaining substantially constant one or more operating conditions selected from the group consisting of temperature, air-fuel ratio, and combinations thereof; [0098] Tests in category (b) typically are durability tests, which evaluate the physical integrity of the component(s) exposed to exhaust gas produced using alternative fuel(s). In such tests, the alternate conditions generally comprise heat, via the exhaust gas, and comprise additional stress conditions other than thermal stress. Examples of additional stress conditions include, but are not necessarily limited to, exposure to liquid, exposure to vibration, exposure to acceleration or acceleration force, change In component orientation, repetitive exposure to any of the foregoing, and combinations thereof. Hot vibration testing and quench testing are exemplary, and are described in more detail below: -Hot Vibration Testing [0099] In hot vibration testing, the FOCAS® rig or other NEBECRAS is substituted for a gasoline engine or other heating apparatus in a known hot vibration testing rig, such as that described in U.S. Patent No. 6,298,729, incorporated herein by reference. Referring to Fig. 5, the exhaust product comprising alternative fuel exhaust generated by the NEBECRAS 300 fluidly communicates with the test fixture 320 via plumbing 310. The apparatus is in mechanical communication with a vibration generator 330, preferably via a slip joint 340. The components) 330 are placed in the test fixture 320 in mechanical communication with the vibration generator 330, preferably a vibration table, which fluidly communicates 310 with the hot exhaust gas generated by the NEBECRAS, preferably a FOCAS® rig. In a preferred embodiment, the test component(s) are fastened to a shaker table which is sealingly engaged with exhaust gas plumbing 310 via a slip joint 340. The shaker table and/or fixtures appended thereto are adapted to provide vertical, horizontal, and angled component orientations. The component(s) are subjected to extended periods of exposure to vibration and steady-state or transient hot exhaust gas flow. [00100] In a preferred embodiment, the component is fixed to a shaker table and exposed to exhaust product comprising alternative fuel exhaust. The vibration table is activated to vibrate at a predetermined vibration frequency and amplitude, and the acceleration of the component is determined by a detector in rigid attachment to the component (not shown). The amplitudes of the excitation energy simulate the range of motion that the component would encounter on an actual vehicle. The input amplitudes of the applied vibration may be increased to accelerate test severity, and the frequency distribution of the vibration may be set to match exhaust system vibration conditions for a particular motor vehicle or for particular vehicle operating conditions. [00101] The forces transferred across the component are detected by a load cell and collected and analyzed as testing progresses. In general, the forces transmitted to the component during each test will decrease over time in approximate proportion to the number of vibration cycles to which the component is exposed. [00102] The vibration generator may have any suitable structure. See, e.g., U.S. Patent No. 6,672,434; U.S. Patent Application Publication 20040025608, incorporated herein by reference. -Water Quench Testing - [00103] Water quench testing simulates conditions when the catalytic converter of a vehicle is exposed to water as, for example, when the vehicle drives through a puddle or a flooded area. In water quench tests, the component is exposed to exhaust product comprising alternative fuel exhaust at relatively constant temperature, but the component surface is rapidly cooled with water. The water may be fresh or saltwater, and may comprise contaminants. [00104] The rig used to perform water quench tests will include a liquid feed member in fluid communication with a source of liquid and with the test component surface, preferably a catalytic converter surface. The liquid feed member is activated during the test to expose the surface to the water, either a single time or repeatedly. In a preferred embodiment, the liquid feed member, preferably a nozzle or manifold apparatus, is effective to spray the surface of the component with water. The component is then evaluated using known methods to assess the impact of the surface cooling on the component. [00105] As seen above, preferred alternate conditions include, but are not necessarily limited to repetitive heating and cooling periods, stepwise temperature increases, rapid changing of temperature, exposure to external water, sweep tests using gradually increased air to fuel ratios, and combinations thereof. [00106] Persons of ordinary skill in the art will recognize that many modifications may be made to the present application without departing from the spirit and scope of the application. The embodiment described herein is meant to be illustrative only and should not be taken as limiting the application, which is defined in the claims.