Euro norms

Euro norm are meant for regulating vehicular emissions in Europe. The norms are expressed in terms of the weight of pollutants such as carbon monoxide (CO), hydrocarbon, oxides of nitrogen (NOx) and particulate matter emitted per kilometer of vehicular run with load. These ceilings have been fixed for various categories of vehicles. For instance, there are emission levels for petrol-driven and diesel-driven vehicles based on the capacity of the engines. The pollution measurements under engine idling conditions without application of load on the vehicles does not reflect the exact quantum of various pollution emitted by the engines in reality.

In any internal combustion engines, as the speed or acceleration is increased, the time allowed for combustion of the fuel is varied than the idling condition. This variation is different in a carburetor engine and in a fuel injection petrol or diesel engine. In a carburetor engine, the CO will be maximum at idling speed. In a diesel engine, the smoke will be maximum upon sudden acceleration. The Euro norms adopt certain specified driving cycles related with time Vs speed. During these cycles of operation of the engine, the mass of each exhaust gas component is evaluated. The mass is exhaust gas volume. Exhaust gas is generated when the vehicle is operated on a chassis dynamometer according to certain standard driving cycles which stimulate driving conditions in urban traffic.