Due to complete combustion
Due to incomplete combustion
Due to excess air supplied
Due to atmospheric mixture
Combo of PCV and EGR
Combo of EGR and SCR
Combo of PCV and 3 way catalytic connection
Combo of DPF and EGR
To prevent pressure build up
To prevent temperature build up
To increase the blow by gas
To reduce the combustion leak
Use of back pressure to increase efficiency
HC present in blow by drawn out
HC present in the blow by reused
Increase the crank case dilution
Exhaust system and intake system
Crank case and intake system
Crank case and exhaust system
Exhaust system and catalytic converter