Emission Control Systems: Description and Operation

In order to reduce exhaust emissions, these vehicles utilize a deceleration control system, an evaporative emission control system, exhaust gas recirculation system, positive crankcase ventilation system, three way catalytic converter and electronic gasoline injection.

EVAPORATIVE EMISSION CONTROL SYSTEM (EVAP)

The evaporative emission control system stores fuel vapor generated in the fuel tank in the canister when the engine is not running. The fuel vapor is stored in the canister until it is drawn into the dynamic chamber and burned when the engine is started.

EXHAUST GAS RECIRCULATION SYSTEM (EGR)

The exhaust gas recirculation system introduces exhaust gas into the intake manifold to reduce NOx in the in the exhaust gas. It operates depending on engine load, engine speed, and coolant temperature.

POSITIVE CRANKCASE VENTILATION SYSTEM (PCV)

The PCV valve is operated by intake manifold vacuum. When the engine is running at idle, the PCV valve is opened slightly and a small amount of blow-by gas is drawn into the engine. At higher engine speeds, the PCV valve is further opened and a larger amount of blow-by gas is drawn into the engine.

THREE WAY CATALYTIC CONVERTER (TWC)

The catalytic converter is used to reduce CO, HC, and NOx. To accomplish this, the three-way converter is filled with a compound of platinum and rhodium.