Catalytic Converter: Description and Operation

Fig. 10 Exhaust System:

Catalytic converters are installed in the exhaust system to reduce the amount of CO and HC emitted into the atmosphere. Two ceramic monolith catalytic converters are mounted in the exhaust system, Fig. 10, the first in the header pipe close to the engine, and the second, mounted in the exhaust system under the vehicle.
For the converters to operate properly, it is necessary to control the oxygen concentration in the exhaust gas entering the converter. This is achieved by the engine management system which uses an oxygen sensor to constantly monitor the oxygen content of the exhaust system. From the oxygen sensor measurements, the engine management computer can adjust the amount of fuel injected into the cylinders to obtain the required oxygen content in the exhaust gases.
To prevent damage to the catalytic converters, unleaded fuel must be used in the vehicle. In order to meet this goal, the filler neck is designed to accommodate unleaded fuel pump nozzles only.