Technical Paper
A Simple Test Method to Monitor Emission Control Operating State Space (Emission Control Failure & Defeat Device Recognition)
2016-10-17
2016-01-2324
Modern light-duty vehicles require well-controlled engine-out feed-gas and very high catalyst efficiencies to meet the US Environmental Protection Agency (EPA) Tier 2 & 3 standards. When a vehicle with either a gasoline or diesel engine is operating within its controlled state-space the exhaust emissions present at the tailpipe are extremely low. When it is not operating within its controlled state-space the combustion process and therefore its exhaust emissions characteristics will be different. This may occur when an emission control device fails or if a defeat device is employed. Moreover, different control technologies each have unique characteristics or signatures that could assist in identifying either emission control device failure or an existing defeat device.
