Petrol engine

A petrol engine is an internal-combustion engine that burns petrol, usually igniting a compressed air–fuel mixture with a spark plug. Its common four-stroke cycle draws in, compresses, ignites, and expels gases.

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Four-stroke engine: An internal-combustion engine cycle with intake, compression, power, and exhaust strokes. This cycle is the standard operating sequence for most petrol car engines.
Internal combustion engine: An engine that releases chemical energy by burning fuel inside a working chamber. A petrol engine is one fuel-specific form of this broader engine family.
Diesel engine: An internal-combustion engine that ignites fuel through compression heating rather than a spark plug. Its compression-ignition process contrasts with the petrol engine’s spark ignition.
Catalytic converter: An exhaust device that converts harmful pollutants into less harmful gases using catalytic reactions. Petrol vehicles use it to reduce carbon monoxide, hydrocarbons, and nitrogen oxides.
Automobile: A road vehicle designed primarily to carry people and powered by an onboard propulsion system. Petrol engines powered most automobiles for much of the twentieth and early twenty-first centuries.
Spark-ignition engine: An internal-combustion engine that ignites its air–fuel charge using an electric spark. Petrol engines are the most common type of spark-ignition engine.
Cylinder (engine): A chamber in which an engine piston moves and, in many engines, fuel combustion occurs. Each cylinder contains the changing volume where the charge is compressed and burned.
Compression ignition: Combustion initiated when injected fuel meets air heated by compression. Petrol engines normally use a spark instead of relying on compression to ignite fuel.
Turbocharger: An exhaust-driven compressor that forces more air into an engine’s cylinders. It can raise a petrol engine’s power without increasing its displacement.
Petroleum: A naturally occurring mixture of hydrocarbons refined into fuels and chemical feedstocks. Petrol engines depend on refined petroleum as their principal fuel source.