Indian Evaporative Emission Test Procedure and Parametric Study of Test Variables

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. Using this test facility, a series of evaporative emission tests were conducted on different types of vehicles by varying test parameters like vehicle preconditioning, vehicle soak period, diurnal heat build cycle temperature and volume of fuel filled etc.. Efforts were also made to establish correlation between the preconditioning diurnal heat build results and the Diurnal breathing loss test results. Effect of driving cycle used, on evaporative emissions was assessed.