Petrol engine exhaust emissions contain harmful gases such as Carbon Monoxide (CO), Hydro Carbons (HC) and Nitrogen (NOx) the by - product of incomplete combustion in the engine and their concentration, depends mainly on the temperature developed in the combustion chamber, during the process of combustion which takes place inside the engine in the cylinder head during the firing stroke.
Inside the catalytic converter, the toxic elements and the exhaust gas are rendered innocuous.
The electronic injection system makes it possible to feed the engine with the required measure of air and petrol in all operating conditions, through the air flow sensor. The lambda sensor serves to monitor the correct oxygen content in the exhaust gas, which is important if the catalytic converter is to function efficiently, signaling any defects or excesses to the electronic injection computer controlled unit.
By C L Liyanasuriya, Headquarters Engineer, AAC