The actual European projects on HDV (Heavy Duty Vehicles) emission factors are almost finalized, providing results for EURO 0 to EURO 3 based on a large number of measured engines and vehicles, while the emissions of EURO 4 and 5 are based on assumptions only. The emission behavior of the modern HD engines measured in the projects as well as the emission factors calculated showed that real world emission levels can differ significantly from the type approval levels. Mainly NOx emissions proved to be higher in real world cycles than in the R 49 or ESC from EURO 2 on. This is due to the trade-off between fuel consumption and NOx emissions. Since engines have to be robust and fuel efficient to be competitive on the market, engines are optimized towards low fuel consumption whenever possible. This resulted in rather high NOx-emissions outside of the type approval tests. Even an ideal type approval system for actual technologies may soon have gaps for future technologies. Thus in-use tests based on real world driving with the complete vehicle using on board emission measurement equipment or roller test bed measurements may be an important tool in future when low emissions shall be guaranteed. Such in-use tests could also check the durability of the new technologies introduced with EURO 4 and EURO 5. Such tests would have to be performed in time to be able to react as long as the vehicles are still produced. This means that such a program has to be started immediately. Such in-use tests could also be used to feed the emission factor model PHEM (Passenger car and Heavy duty vehicle Emission Model) with data for easy updates if the test program is designed correspondingly. In ARTEMIS WP 300 it has been shown that the model PHEM can transfer instantaneous emission measurements from transient cycles on the roller test bed into useful engine emission maps to produce emission factors. Such a method could lower the costs for updates significantly since measurements on the engine test bed for in-use EURO 5 HDV may become very expensive due to the complex technology. Even more, engine tests without special engine control units may become quite impossible for future HD engines, thus new methods are necessary if tests independent from the manufacturers shall be preformed.
Emissions from heavy duty vehicles
Emissionen aus Schwerlastfahrzeugen
incl. COST 346 - Final Conference, Transport and Air Pollution, International Symposium, 14 ; 211-220
2005
10 Seiten, 6 Bilder, 11 Quellen
Aufsatz (Konferenz)
Englisch
Exhaust Emissions from Heavy Duty Vehicles
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