Petrol – Its Composition, Octane Rating: Quick Guide

What is petrol made up of? What is its composition? What are the different octane numbers? – Here is a quick article for common know-how…

You use petrol to fill up your bike’s tank and after your tank gets empty you go back again to fill it up. All this is fine but have you ever wondered what petrol is? Probably not I guess! So, let us understand what powers our motorcycles…

A Derivative: Petrol is extracted from crude oil and there are many derivatives which are extracted from crude oil – Diesel, Kerosene, LPG, CNG, White kerosene (aviation fuel), petrol, ethanol, methanol, to name a few. International crude oil rates touched high records of $150-160 per barrel in 2008. The rates have come down ever since and currently, it is hovering around the $60 per barrel mark. The OPEC (Organisation of the Petroleum Exporting Countries) estimates that there is enough crude oil in the world to last another 70-80 years only!

what is petrol

Octane Rating: The normal unleaded petrol you use generally has an octane rating of 87 or higher. The higher octane petrols available in India are 91, 93 which are sold as premium fuels. Speed 97 is the highest rated fuel and is limited for the most high-end motorcycles and cars.

Composition: Petrol is made up of aliphatic and aromatic hydrocarbons along with toluene and benzene. In this, toluene is an explosive and it is used as TNT (trinitrotoluene) in explosives. That’s why petrol is highly inflammable and can explode when it comes in contact with fire. Benzene and Toluene are added to increase the octane rating.

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The higher the octane rating the greater is the resistance of petrol to explosion, which is why all high performance engines need high octane fuels. High performance engines have high compression ratios compared to normal engines – they produce more power and are high revving. In generic terms, the higher the compression ratio the more efficient an engine is.

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So in a nutshell, despite various alternate sources of energy that have emerged in the recent years, petrol continues to power most of the motorcycles in the world. It would be very hard to imagine life without petrol – use it carefully and judiciously and don’t waste it! Little wonder its called Liquid Gold.