Service Catalytic converter

Service Catalytic converter

Catalytic Converter: -

The catalytic converter converts harmful pollutants in the exhaust gas into harmless gases. It is located in the exhaust system and all exhaust must flow through it.The catalyst is a material in the catalytic converter that causes a chemical change without being a part of the chemical reaction. A catalytic converter may have two different catalysts. One treats the HC and CO. The other treats NOx components. The catalyst for HC and CO encourages HC to unite with O2 to become H2O (Water) and CO2 (Carbon Dioxide). It also encourages Co to unite and form CO2 compound. It is also called as oxidizing converter. The catalyst for NOx works differently. It splits the oxygen and nitrogen. This neutralizes the Harmfulness of NOx and becomes a reducing converter.

Important: -

If leaded gasoline is used, the surface of converter becomes coated with lead and loose it effectiveness for the reason vehicles equipped with a catalytic converter must always use gasoline.

Operation of temperature catalyst: -

 “Purification Rate” is used as the measure of the proportion of the pollutants present in the exhaust gases that can be converted into pollutants. 

There are three catalytic converter system: -

 i. Oxidation catalytic system

ii. Two-way catalytic system

iii. Three-way catalytic system

Catalytic Converter Service: - Diagnosis:

Catalytic converter trouble is indicated by noise, small particles coming out of tail pipe, and rotten egg smell. Other signs are high HC, CO and NOx levels in exhaust gas and power loss due to a restricted catalytic converter. Noise could be due to loose exhaust-pipe joints, and a loose or missing converter fill plug. Small particles coming out of the tail pipe mean the converter has overheated so the pellet support has warped. Replace a damage or overheated catalytic converter. A rotten-egg smell is due to sulphur in the gasoline. The converter combines the sulphur with hydrogen to produce hydrogen sulphide which produces the smell.

Testing Exhaust Back Pressure: -

The catalytic converter on a properly-maintained engine running only on unleaded petrol should last the life of the vehicle. However, the converter may be damaged, ineffective or clogged. To check exhaust backpressure, remove the oxygen sensor and install a backpressure tester. This is low-reading pressure gauge similar to the fuel-pump pressure tester. With the engine at normal operating temperature and running at 2500 rpm, read the back pressure on the gauge. On some cars it exceeds 1.25 psi (8.62 kPa) indicated a restricted exhaust system. Other engines may have a higher allowable backpressure. Follow the specifications in vehicle service manual. 

Service: -

• The catalytic converter requires no service or maintenance in normal condition.

• Damage or overheated converters must be replaced. They are not repairable.

• The old beads can be removed and a fresh charge of beads installed.

• The vacuum pump is turned on while the vibrator and can is attached to the beads pulling out the beads which will start falling in the can.

• It is about 10 min to clear the converter.