Measuring Vehicle Performance on Road & on Dynamometer

Automobiles are the major source of atmospheric pollution international causing various health and environmental related risks. Regardless of the importance, the exhaust automotive emissions are inefficiently understood and enumerated. The increasing sizes of urban areas, increasing vehicle population and increased driving distances have led to serious pollution levels in many cities. With reduction in the emission limits the air quality, has not improved considerable as prophesied, mainly intended for NOx emissions. One of the main causes for the gap is the emission measurement under the legislative test cycles and their efficacy during the actual driving conditions. A vehicular emission needs to be modelled and derived from the actual driving conditions rather than the legislated drive cycle data. For commercial vehicles the main gap lies in the repeatedly used engine speeds that these falls outside the range presently experienced under the type approval testing. India follows a dual fuel policy and dieselization of India’s automobile with subsidies for diesel fuel increasing the particulate matter emissions. Realistic exhaust emissions rests largely on elements such as dynamic driving pattern, atmospheric circumstances, fuel quality, road conditions, altitude variation and vehicle aging. Major pollutants like NOX, CO, PM and VOC differ under dynamic condition than those under the steady state. India is following European emission standards, besides the road conditions and vehicle specifications are not up to those standards. This study aims to identify the emission gap on the base of evaluation and assessment of operating circumstances underneath legislative test cycles and the actual driving conditions in the normal traffic. The vehicle was equipped for logging of various engine and vehicle related parameters. The operating conditions were divided into three parts rural, urban and highway.