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Three Way Catalytic converters (TWC's) have been in use around the world for the past 25 years or more. As the world progresses towards tighter and tighter automotive emission regulations, not only is it necessary to make catalysts more durable, but also better tests have to be developed to prove their durability. In the fresh state, catalytic converters are extremely efficient in converting the emissions going through them. However, as the vehicle and emission control system ages, the catalyst tends to degrade and lose its efficiency. Traditionally, automotive manufacturers around the world have developed customized catalyst aging cycles, which demonstrate the durability of the emission control system. In this paper, we will discuss some of the catalyst deactivation mechanisms and methods to simulate them using dynamometer-mounted engines. Methods used for testing dynamometer-aged emissions control systems will also be discussed.

The exhaust emission legislation for automotive vehicles came into effect in India from 1991. Since then, the exhaust mass emission certification tests are conducted on a prototype vehicle for emission compliance before commencing commercial production. The exhaust emission norms are reviewed and tightened after every five years. This should lead to a better emission control system in new vehicles. But the old vehicles which are designed prior to emission control era continue to emit heavily due to their inherent design and condition. The problem of in use vehicle emissions will be on the rise with the low scrappage rate of old vehicles in India. The impact of implementing tighter norms for new vehicles on ambient air quality can be felt only after a period of about 10 years. To have an effective improvement in ambient air quality levels, it is necessary to identify the gross polluters and retune them for bringing their emissions to an acceptable level.

In India, evaporative emission norms came into effect from 1st April 1996. The ARAI commissioned a Variable Temperature/Variable Volume SHED for conducting evaporative emission tests on all Passenger Cars. The present Indian evaporative emission test procedure is in line with the 91/441/EEC test procedure with the exception of Driving Cycle. As Indian Automotive Industry needs technical inputs for designing evaporative emission control systems, it was decided to collect an exhaustive data base on evaporative emissions. This paper briefly describes evaporative emission test methods adopted in different countries and different requirement of the test equipments and specifications. This paper also describes the commissioned VT/VV SHED System capabilities and its specifications.