what is the basic difference between bsiii and bsiv engine?
Compared to the BS4, the BS6 fuel has less sulphur and NOx. While the content of sulphur in BS4 fuel is 50ppm, it is five times lower in the BS6 fuel, which is at 10ppm. As for the nitrogen oxide, the permitted level has been reduced by 70% and 25% for diesel and petrol engines, respectively.