ANDERSON ANDY M
WEBB CYNTHIA C
BYKOWSKI BRUCE B
US4651524A | 1987-03-24 | |||
US6490858B2 | 2002-12-10 |
We claim: L A method for simulating at least one drive cycle of a vehicle using a non-engine based test system, the method comprising: providing a non-engine based test system comprising a combustor in fluid communication with a catalytic converter from said vehicle; supplying fuel and air to said combustor at an air to fuel ratio (AFR) and under conditions effective to produce a feedstream flowpath; substantially stoichiometrically combusting at least a portion of said fuel in said feedstream flowpath under conditions effective to simulate at least one drive cycle of said vehicle and to produce a simulated drive cycle exhaust product for said vehicle, said conditions being effective to prevent substantial damage to said combustor; and collecting and analyzing said simulated drive cycle exhaust product. 2. The method of claim 1 wherein said supplying fuel and air occurs through a component which produces a feedstream flowpath comprising an air shroud effective to prevent flame from attaching to said component during said combusting. 3. The method of claim 1 wherein said supplying fuel and air produces a feedstream flowpath effective to prevent flame from remaining in constant contact with an inner wall of said combustor during said combusting. 4. The method of claim 2 wherein said supplying fuel and air produces a feedstream flowpath effective to prevent flame from remaining in constant contact with an inner wall of said combustor during said combusting. 5. The method of claim 1 wherein said drive cycle is a nonrepetitive drive cycle covering 7.5 miles in 1372 seconds with an average speed of 19.7 mph. and a maximum speed of 56.7 mph. 6. The method of claim 2 wherein said drive cycle is a nonrepetitive drive cycle covering 7.5 miles in 1372 seconds with an average speed of 19.7 mph. and a maximum speed of 56.7 mph. 7. The method of claim 3 wherein said drive cycle is a nonrepetitive drive cycle covering 7.5 miles in 1372 seconds with an average speed of 19.7 mph. and a maximum speed of 56.7 mph. 8. The method of claim 4 wherein said drive cycle is a nonrepetitive drive cycle covering 7.5 miles in 1372 seconds with an average speed of 19.7 mph. and a maximum speed of 56.7 mph. 9. The method of claim 1 wherein said drive cycle consists essentially of: a cold-start, 505-second, cold transient phase effective to produce a phase I product; followed by an 864-second stabilized phase effective to produce a phase II product; followed by a 10 minute soak phase; followed by a hot-start, 505-second, hot transient phase effective to produce a phase III product. 10. The method of claim 3 wherein said drive cycle consists essentially of: a cold-start, 505-second, cold transient phase effective to produce a phase I product; followed by an 864-second stabilized phase effective to produce a phase II product; followed by a 10 minute soak phase; followed by a hot-start, 505-second, hot transient phase effective to produce a phase III product. 11. The method of claim 4 wherein said drive cycle consists essentially of: a cold-start, 505-second, cold transient phase effective to produce a phase I product; followed by an 864-second stabilized phase effective to produce a phase II product; followed by a 10 minute soak phase; followed by a hot-start, 505-second, hot transient phase effective to produce a phase III product. 12. The method of any of claims 1-10 and 11 wherein said analyzing said simulated drive cycle exhaust product comprises: diluting and mixing said simulated drive cycle exhaust product with filtered background air to a known constant volume flowrate to produce a dilute exhaust product; analyzing a proportional sample of said dilute exhaust product for emissions; and, mathematically weighting said emissions to represent weighted emissions for each simulated trip from cold start to hot start. 13. The method of any of claims 1-10 and 11 wherein said drive cycle simulates a distance of 11.04 miles at an average speed of 21.2 miles per hour. 14. The method of claim 12 wherein said drive cycle simulates a distance of 11.04 miles at an average speed of 21.2 miles per hour. 15. The method of claim 1-10 and 11 further comprising cooling said non-engine based test system to ambient conditions; and substantially immediately after said cooling, combusting fuel in a subsequent air and fuel mixing feedstream under conditions effective to simulate at least one subsequent drive cycle, producing a subsequent simulated drive cycle exhaust product; and collecting and analyzing said subsequent simulated drive cycle exhaust product. 16. The method of claim 12 further comprising cooling said non-engine based test system to ambient conditions; and substantially immediately after said cooling, combusting fuel in a subsequent air and fuel mixing feedstream under conditions effective to simulate at least one subsequent drive cycle, producing a subsequent simulated drive cycle exhaust product; and collecting and analyzing said subsequent simulated drive cycle exhaust product. 17. The method of claim 14 further comprising cooling said non-engine based test system to ambient conditions; and substantially immediately after said cooling, combusting fuel in a subsequent air and fuel mixing feedstream under conditions effective to simulate at least one subsequent drive cycle, producing a subsequent simulated drive cycle exhaust product; and collecting and analyzing said subsequent simulated drive cycle exhaust product. 18. The method of claim 1-10 and 11 further comprising combusting at least a portion of said fuel while varying: exhaust flowrate within a range of from 0 to about 200 standard cubic feet per minute (scfm); exhaust gas temperature within a range of from about 20 to about 900 0C; and, exhaust gas stoichiometry within from about 10 to about 40 AFR, thereby simulating at least one drive cycle, producing a simulated drive cycle exhaust product for said vehicle; and collecting and analyzing said simulated drive cycle exhaust product. 19. The method of claim 18 further comprising varying said exhaust gas stoichiometry within from about 10 to about 20 AFR. 20. The method of claim 16 further comprising combusting at least a portion of said fuel while varying: exhaust flowrate within a range of from 0 to about 200 standard cubic feet per minute (scfm); exhaust gas temperature within a range of from about 20 to about 900 0C; and, exhaust gas stoichiometry within from about 10 to about 40 AFR, thereby simulating at least one drive cycle, producing a simulated drive cycle exhaust product for said vehicle; and collecting and analyzing said simulated drive cycle exhaust product. 21. The method of claim 20 further comprising varying said exhaust gas stoichiometry within from about 10 to about 20 AFR. 22. A method for simulating at least one drive cycle of a vehicle using a non-engine based test system, the method comprising: providing a non-engine based test system comprising a combustor in fluid communication with a catalytic converter from said vehicle; supplying fuel and air to said combustor under conditions effective to produce an idealized simulated exhaust gas and to simulate operation of said vehicle during at least one drive cycle, producing a simulated drive cycle exhaust product for said vehicle; and, collecting and analyzing said simulated drive cycle exhaust product. 23. The method of claim 22 wherein said idealized simulated exhaust gas comprises NOx. 24. The method of claim 22 wherein said supplying fuel and air to said combustor occurs via a component which produces a feedstream flowpath comprising an air shroud effective to prevent flame from attaching to the component during combustion of the fuel and to prevent flame from remaining in constant contact with an inner wall of the combustor tube during combustion of the fuel. 25. The method of claim 23 wherein said supplying fuel and air to said combustor occurs via a component which produces a feedstream flowpath comprising an air shroud effective to prevent flame from attaching to the component during combustion of the fuel and to prevent flame from remaining in constant contact with an inner wall of the combustor tube during combustion of the fuel. 26. The method of claim 22 further comprising substantially continuously and effectively stoichiometrically combusting said fuel. 27. The method of claim 24 further comprising substantially continuously and effectively stoichiometrically combusting said fuel. 28. The method of claim 25 further comprising substantially continuously and effectively stoichiometrically combusting said fuel. 29. The method of claim 28 wherein said drive cycle is a nonrepetitive drive cycle covering 7.5 miles in 1372 seconds with an average speed of 19.7 mph. and a maximum speed of 56.7 mph. 30. The method of claims 22-28 and 29 wherein said drive cycle consists essentially of: a cold-start, 505-second, cold transient phase effective to produce a phase I product; followed by an 864-second stabilized phase effective to produce a phase II product; followed by a 10 minute soak phase; followed by a hot-start, 505-second, hot transient phase effective to produce a phase III product. 31. The method of claim 30 wherein said drive cycle simulates a distance of 11.04 miles at an average speed of 21.2 miles per hour. 32. The method of claim 30 wherein said analyzing said simulated drive cycle exhaust product comprises: diluting and mixing said simulated drive cycle exhaust product with filtered background air to a known constant volume flowrate to produce a dilute exhaust product; analyzing a proportional sample of said dilute exhaust product for emissions; and, mathematically weighting said emissions to represent weighted emissions for each simulated trip from cold start to hot start. 33. The method of claim 32 further comprising cooling said non-engine based test system to ambient conditions; and substantially immediately after said cooling, combusting fuel in a subsequent air and fuel mixing feedstream under conditions effective to simulate at least one subsequent drive cycle, producing a subsequent simulated drive cycle exhaust product; and collecting and analyzing said subsequent simulated drive cycle exhaust product. |
[0019] The non-engine based test system software controls all of the above parameters simultaneously throughout the simulated FTP, and is programmable to simulate any desired set of test conditions. [0020] Throughout the test cycle, the exhaust is collected, diluted, and thoroughly mixed with filtered background air to a known constant volume flowrate using a positive displacement pump. This procedure is known as Constant Volume Sampling (CVS). A proportional sample of the dilute exhaust is collected in a sample bag for analysis at the end of the test. The emissions are mathematically weighted to represent the average of several 7.5 mile trips made from cold and hot starts. A summary of suitable cycle duration, driving distance, and average speed is given in the following Table:
Exhaust emissions from the FTP cover the effects of vehicle and emission control system warm-up as the vehicle is operated over the cycle. The "stabilized" phase produces emissions from a fully warmed up or stabilized vehicle and emission control system. "Hot-start" or "hot transient" phase emissions result when the vehicle is started after the vehicle and emission control systems have stabilized during operation, and are then soaked (turned off) for 10 minutes. [0021] Weighted total emissions from the FTP at 680F to 860F ambient temperature conditions are regulated by the EPA. The only regulated pollutant for the FTP at cold conditions (2O0F) is carbon monoxide (CO). Tier 1 cold-CO level for passenger cars is 10.0 g/mile. The California LEVII emissions standards for 2004 light-duty passenger cars, intermediate life - 50,000 miles (the standards which the test vehicle was certified to) are: NMOG: 0.04 g/mile CO: 1.7 g/mile NOx: 0.07 g/mile The weighted total mass equivalent emissions for the EPA FTP-75 are calculated as required in the U.S. EPA regulations (40 CFR 86.144-90) using the following equation: Weighted g/mile = 0.43 x Phase 1 grams + Phase 2 grams Phase 1 miles + Phase 2 miles
+ 0.57 x Phase 3 grams + Phase 2 grams Phase 3 miles + Phase 2 miles
[0022] The non-engine based test system, preferably a FOCAS ® system, can be used for thermal aging. As a result, the burner may be deactivated at a predetermined age, the system may be cooled to ambient conditions in a matter of minutes, and then immediately after cooling, the system can be used to perform multiple simulated FTP's. The non-engine based test system can then be returned to aging, making the entire emissions test procedure very time-efficient. These advantages make it highly desirable as a research and development tool. [0023] 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.