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Field endurance testing in New Delhi and surrounding area roads demonstrates the potential of catalytic devices for delivering long term reductions of HC + NOx and CO emissions from 2-wheel vehicles. Typically, catalytic performance is monitored periodically using chasis dynamometer mass emission test procedures. Unfortunately, mass emission testing is resource and time consuming. However, there is a relatively simple method for semi-continuously monitoring changes in catalyst performance during road aging. This relatively simple method of catalyst performance monitoring is discussed in this paper. In addition, the impact of extended vehicle operation during field testing and dynamometer endurance runs on catalyst performance is assessed for both 2 and 4 stroke motorcycles. Results examining catalyst deactivation mechanisms are examined for 2-wheel vehicles equipped with these 2 and 4 stroke engines.

Scooters and motorcycles are favoured as economical forms of transportation throughout much of Asia. This is particularly true of vehicles with 2-stroke powerplants, thanks to the high specific output produced by this simpler, less costly engine. However, a serious disadvantage of these vehicles is that they emit considerably higher volumes of gaseous pollutants per driven kilometer than do other automobiles. Reductions of greater than 50% in these gaseous emissions can be effected through the use of catalysts to treat the exhaust from these engines. In this paper, important aspects of the operating conditions and durability requirements which must be factored into the design of durable, active catalyst formulations for these vehicles will be described.

While often treated as separate entities, there is a significant interaction between engine operating parameters and the catalytic aftertreatment system in determining overall performance. The impressive gains in vehicle emissions and durability required for such marketplaces, as California and Europe provide excellent examples of this interrelationship. Similarly, the Indian marketplace can expect to follow these technology progressions in engine as well as catalyst application design. To progress from an unregulated emissions environment to the first level of catalyzed aftertreatment of relatively simply designed carbureted engines, and then to more sophisticated engines with fuel injection, India can take advantage of what has been learned in other marketplaces worldwide.