Catalytic Converter: Description and Operation

Fig. 10 Exhaust System:

PURPOSE AND OPERATION
The 4.0L engine utilizes ceramic monolith converters fitted in the exhaust system to reduce carbon monoxide (CO) and hydrocarbon (HC) emissions. One of these (downpipe converter) is close to the engine and a pair are under the vehicle. Platinum and rhodium are commonly used as catalysts to stimulate reactions which reduce exhaust gases to carbon dioxide and water vapor.

To achieve optimum converter operation, the computerized engine management system continuously monitors exhaust gas oxygen content with an oxygen sensor and adjusts air/fuel ratio as required.