BS full form is “Bharat stage”. It is a emission standard. The main difference between the BS2and BS3 engines is to present in the catalytic converter. In the BS3 engine the catalytic converter is used to reduced the formation of the HC and CO. And in the BS2 engines the catalytic converter is does not used for the formation of HC and CO. In the BS3 engines there is no harmful emissions in the HC and CO.
The emission of these type of BS2 contains:
Sulphur – 0.5 g/kg.
Lead – 0.013 g/liter.
The emission of these type of BS3 contains:
Sulphur – 150 mg/kg for gasoline, and 350 mg/kg for diesel.
Lead – 0.005 g/liter.