Exhaust emission control components (Emission control - V8) (page 2 of 2)

The catalytic converter's housings are fabricated from stainless steel and are fully welded at all joints. Each catalytic converter contains two elements comprising of an extruded ceramic substrate which is formed into a honeycomb of small cells with a density of 62 cells / cm². The ceramic element is coated with a special surface treatment called 'washcoat' which increases the surface area of the catalyst element by approximately 7000 times. A coating is applied to the washcoat which contains the precious elements Platinum, Palladium and Rhodium in the following relative concentrations: 1 Pt : 21.6 PD : 1 Rh

Catalytic converters for NAS low emission vehicles (LEVs) from 2000MY have active constituents of palladium and rhodium only. The active constituents are 14PD: 1Rh and the palladium coating is used to oxidise the carbon monoxide and hydrocarbons in the exhaust gas.

The metallic coating of platinum and palladium oxidize the carbon monoxide and hydrocarbons and convert them into water (H₂O) and carbon dioxide (CO₂). The coating of rhodium removes the oxygen from nitrogen oxide (NO_x) and converts it into nitrogen (N₂).

CAUTION: Catalytic converters contain ceramic material, which is very fragile. Avoid heavy impacts on the converter casing.

Downstream of the catalytic converters, the exhaust front pipes merge into a single pipe terminating at a flange joint which connects to the exhaust intermediate pipe.

WARNING: To prevent personal injury from a hot exhaust system, do not attempt to disconnect any components until the exhaust system has cooled down.

CAUTION: Serious damage to the catalytic converter will occur if leaded fuel is used. The fuel tank filler neck is designed to accommodate only unleaded fuel pump nozzles.

CAUTION: Serious damage to the engine may occur if a lower octane number fuel than recommended is used. Serious damage to the catalytic converter will occur if leaded fuel is used.

Heated oxygen sensor

1 Connection cable 2 Disc spring 3 Ceramic support tube 4 Protective sleeve 5 Clamp connection for heating element 6 Heating element 7 Contact element

8 Sensor housing 9 Active sensor ceramic 10 Protective tube 11 Post-catalytic converter sensor (NAS spec. only) 12 Pre-catalytic converter sensor