Petrol or Gasoline, in technical terms, is called Motor Spirit (MS) or Automotive Gasoline. Petrol is normally produced by Refineries by the fractional distillation of crude oil, with further treatment including the addition of multifunction additives to enhance its Octane rating (number) and other properties. Technically, it is a complex mixture of hydrocarbons that are balanced to deliver a satisfactory engine performance over a wide range of operating conditions.

A key parameter for Petrol is the octane number, which is a measure of its resistance to knock. In a spark-ignition engine, the air-fuel mixture gets heated during the compression cycle and is thereafter triggered by the spark plug to burn rapidly, as per the engine design requirements. Higher compression ratios enable the engine to extract more mechanical energy from a given mass of air-fuel mixture, leading to higher thermal efficiency.

With regard to the fuel, gasoline engines with higher design compression ratios typically require fuels with a higher octane rating. Use of petrol with a lower than prescribed octane number may cause the air-fuel mixture to prematurely self-ignite before the ignition system sparks, with a characteristic "knocking" or "pinging" sound, which is undesirable as it may damage engine components due to higher pressures.

Automotive OEMs optimize their individual engine design based on various factors which include fuel efficiency, engine compression ratio, components engineering design, specifications of the fuel etc., Widely used automobile brands in India require Petrol of minimum 91 Octane rating, which is available throughout HPCL’s Retail Outlet Network in India. High-performance cars and motorcycles use higher octane petrol like poWer 99 – India’s highest octane Petrol.

Petrol sold at HPCL Retail Outlets is directly delivered into the automobile fuel tank, as per regulatory requirements. The Petrol marketed by HPCL meets the Indian Standard governing the properties of motor gasoline & gasoline – oxygenate blends IS 2796 : 2017.

The government’s policy guidelines also cover the fuel specifications required to meet emission standards BS-VI standards. HPCL’s Retail Outlet network market fuels meeting the progressively more stringent standards, as per the policy timelines for the geographical region.

An oxygenate, ashless organic compound (such as alcohol or ether) can also be used to supplement the petrol. In relation to the National Policy on Biofuels issued by the Ministry of New & Renewable Energy (Government of India), BIS has published specifications for “Petrol with 10% Ethanol”. As the ethanol molecule contains oxygen, it allows the engine to more completely combust the fuel, resulting in fewer emissions and thereby reducing the occurrence of environmental pollution.

Filter Paper Test (Petrol), Density Test (Petrol & Diesel), Quantity Check.