The non-engine based rapid aging method comprises combusting fuel with air to produce exhaust gas; controlling a temperature of said exhaust gas; supplying said exhaust gas to said exhaust component; and analyzing a composition of said exhaust gas.
[0001] This application claims the benefit of the filing date of U.S. Provisional application Ser. No. 60/200852, filed May 1, 2000, which is incorporated herein in its entirety.
[0002] Catalytic converter performance in an automobile will deteriorate over time due to such things engine misfire, a faulty oxygen sensor, poisoning, or prolonged high temperature operation. Deterioration of the catalytic converter in turn affects the catalyst's effectiveness for preventing the emission of undesired exhaust gases such as carbon monoxide (CO), nitrogen oxides (NO
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[0004] Shell
[0005] Support mat
[0006] The composition of the catalyst is well known in the art and is typically disposed on the substrate
[0007] The catalyst material comprises a multitude of passageways for reacting and converting byproduct exhaust gases.
[0008] However as a catalytic converter ages with use, pores
[0009] Further, a recent trend in legislation of automobile exhaust emissions is being focused on reducing emissions throughout the whole term of usage. To meet emission regulations, an automobile must have a catalytic converter which meets a certain requirement. That is, after 100,000 miles of running, the catalytic converter should maintain its performance of removing undesired emission gases in an optimum level which is required in a related regulation.
[0010] Therefore, it is useful to measure the degradation of a catalyst's performance as it ages. To gauge the aging performance, one method of practice has been to test catalysts by aging the catalysts using road testing with an automobile. However, this method of testing is both costly and time consuming.
[0011] An alternative method has been to modify an engine to artificially age the catalyst in order to avoid the necessity of road testing. As such, attempts have been made to alter the operation of the engine and artificially accelerate the aging process. The purpose of modifying the engine operating conditions is to assure that, after exposure to the accelerated aging, the catalyst reacts to emission gases in a similar manner as the catalysts which have been actually aged on a vehicle.
[0012] To simulate a field aged catalyst, prior methods include placing a catalyst on engine dynamometers and inducing various levels of misfire in order to degrade catalyst performance to the required threshold level. However, under steady state conditions, it is difficult to achieve the necessary temperatures to degrade or age the catalyst to a desired efficiency level within a reasonable time. Also, considerations about the availability of engine dynamometers and other resources required to meet the demand for threshold catalyst hardware with the misfire method may be limited.
[0013] As an alternative method, there has been an oven aging. Catalyst bricks are removed from the converter shell assembly and baked in an oven at temperatures ranging between 1,000 and 1,350° C. for 2-32 hours. After aging, the bricks are recanned and installed onto the vehicle. The vehicle is then usually driven for a few hundred miles to provide for a stabilization or break-in period prior to emission testing. However, it is difficult to determine the appropriate aging time and temperature required to degrade the catalyst performance to a specified level for a given vehicle.
[0014] A non-engine based exhaust component rapid aging system comprises a combustor in fluid communication with an air and a fuel supply; and a first emission analyzer in fluid communication with said combustor, wherein said first emission analyzer and said combustor are further capable of being disposed in fluid communication with an exhaust component; and wherein said non-engine based exhaust component rapid aging system is capable of operation at an air to fuel ratio of about 7 to about 16.
[0015] The non-engine based rapid aging method comprises combusting fuel with air to produce exhaust gas; controlling a temperature of said exhaust gas; supplying said exhaust gas to said exhaust component; and analyzing a composition of said exhaust gas.
[0016] The above-discussed and other features will be appreciated and understood by those skilled in the art from the following detailed description and drawings.
[0017] Referring now to the drawings, which are meant to be exemplary, not limiting:
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[0030] The catalyst rapid aging system described herein can be used to age a catalyst converter, or other test specimen utilizing a feed stream of gases that are of a similar composition, temperature, and mass flow rate as those of a spark ignition engine such as an automobile engine.
[0031] Referring to
[0032] The rapid aging system comprises a combustor
[0033] Following the heat exchanger, a laminar flow element
[0034] The combustor
[0035] By using one or more emission analyzers, the system can be controlled so as to accurately provide exhaust gases to age the test converter
[0036] In
[0037] Thereafter, the exhaust gas flow is directed through the heat exchanger
[0038] After treatment by the rapid aging system, the exhaust gas is fed to the test converter
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[0041] Using the system as shown in
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[0043] Finally,
[0044] As described above, the rapid aging system is non-engine based system. By using the non-engine based rapid aging system, the efficiency of a catalytic converter can be projected throughout its lifetime more accurately and consistently as compared with an engine-based system.
[0045] The non-engine based exhaust component rapid aging system provides advantages of simplifying a catalytic converter test (or other exhaust component) and a testing hardware. This is achieved by eliminating the need for spark ignition engine, e.g., automobile engine, which thereby reduces the costs associated with converter aging and testing. Another advantage is the reduction of testing variability due to the improved controllability of the exhaust gas composition. Pressure, mass flow and temperature of the exhaust gas can be controlled as well. The reduction in testing variability provides better data for design of products such as catalytic converters, oxygen sensors, particulate traps, and the like.
[0046] This system allows for a lean air to fuel testing arrangement, which thereby allows for rapid changes between different products for testing and aging. This is achieved by changing the system control program and test sample. Further, unlike engine based aging systems which operate around stoichiometric air to fuel ratios (12 to about 16.7), this non-engine based system is capable of operating at an air to fuel ratio of about 10 or less, with about 7 or less and even about 2 or less possible. Air to fuel ratios exceeding about 15.5 are similarly possible, with ratios of about 17 and even about 18 or greater possible.
[0047] Since the combustor of the rapid aging system can produce temperatures similar to an engine, performance testing and aging can be accomplished. Further, when the optional heat exchanger is employed, aging time can be diminished and better controlled than with an engine based test rig. In addition to temperature control, the system enables contaminant control by allowing the introduction of, or increased concentration of contaminants, e.g., sulfur, nitrogen oxides, and the like, prior to the exhaust component.
[0048] The non-engine based rapid aging system is highly portable and can be made in a small unit. Also, the system is very safe compared with engine-based systems. It is very simple to control the system, thus, aging variability can be minimized and aging process can be expedited.
[0049] While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.