The catalytic converter is a fundamental component of an engine‘s emission control. Its task is to considerably lower the percentage of harmful pollutants which are a by-product of the burning of petrol. In principle, there are several types of catalytic converters. The most current models presently are the 3-way catalytic converter for petrol engines and the oxidation catalytic converter for Diesel engines. A 3-way catalytic converter reduces toxic pollutants present in exhaust gases through a 3-step “redox reaction” chemical process. During the first step nitrogen oxides are turned into nitrogen, while in the second step carbon monoxide is converted into carbon dioxide. In the third and final step, carbon hydrogen compounds are transformed into water vapour. In the case of catalytic converters for (petrol) spark-ignition engines, the 3 chemical reactions just described take all place simultaneously.
A catalytic converter consists of a stainless steel body, inside which there are substrates (supports) made of either metal or ceramic. These substrates are criss-crossed length-wise by many tiny structures, which enlarge the surface area. The substrates are coated with a highly porous layer of precious metals like platinum, palladium or rhodium, which constitute the effective catalysts. In fact, the chemical reactions, which lead to the purification of exhaust gases, take place here.
Catalytic converters: to clean or to swap
The lifespan of a catalytic converter is proportionally related to a motor vehicle’s own life cycle. In general, the precious metals are used up very slowly, and a catalytic converter undergoes a continuous process of self-cleaning. Potentially, it is possible that it might fill up with soot particles and become, therefore, completely clogged after a while. A faulty catalysing converter causes a considerable drop in performance, with emission levels being very high and the engine noise becoming louder. In many motor vehicles, a malfunctioning catalysing converter will be signalled through a little warning light in the dashboard coming on. Only a repair garage should carry out professional cleaning or a swap of this part. Nevertheless, the costs are not low and it is worth shopping around for the best deal. If a catalysing converter turns out to be indeed faulty, normally it is not possible to have it repaired. Old catalysing converters from scrapped cars represent one of the most sought-after second-hand parts, as they contain precious metals. The financial expenditure varies depending on motor vehicle type and size. Generally speaking, prices oscillate between 40 AED and 1200 AED, according to the precious metal content and the prevailing market rate.