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Questions - Answers Fuels :
	What is the role of the catalytic converter ?
	The catalytic converter reduces the emission of polluting gases into the atmosphere. The combustion inside the engine produces gases which contain highly polluting compounds such as Nox, CO and combustion residues ( HC ). The catalytic converter is a device made up of precious metals such as platinum, rhodium and palladium, it is located on the car's exhaust system . It helps start the oxidation-reduction reactions which transform the polluting molecules coming out from the engine into less harmful substances. Example : CO + ½ O2 -------> CO2
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	What are the consequences of using leaded gasoline into a car equipped with a catalytic converter?
	- The use of leaded gasoline into a car equipped with a catalytic converter damages the catalytic converter. It is said that even if the gasoline tank is filled up only once, the catalytic converter will be out of order. - Lead is like a poison for the catalytic converter. It settles on the converter's coating , totally crippling the chemical process at high temperatures and filling pores at low temperatures.
	Is it possible to use unleaded gasoline for cars without catalytic converters ?
	Yes. But the use of unleaded gasoline in old cars which are not equipped with catalytic converters bring about wear at the level of valve seats. As in old cars, lead compounds contained in gasoline lubricate valve seats and protect them against any premature wear.
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	How is combustion carried out inside a gasoline engine?
	Combustion is initiated by the spark coming from the spark plug inside the cylinder which contains the compressed mixture of air and fuel.
	How is combustion carried out inside a diesel engine ?
	Combustion is initiated by a self ignition of the fuel itself without a spark plug.