An engine helps things move. 
An engine makes power to move things. 


An internal combustion engine makes power by burning fuel. 



An internal combustion engine is a machine that turns fuel into movement. 

There are different ways these engines work depending on their design. In a reciprocating engine, parts like pistons move back and forth. 
Many clever people helped invent and improve these machines over many years. 
Today, we see these engines being used in many different places. 

If you look under the hood of a car, you are seeing an engine block. 
An internal combustion engine (ICE) is a heat engine that converts chemical energy into kinetic energy. 

In a reciprocating engine, the movement is based on parts sliding back and forth. The base of these engines is the engine block. 

Inside the cylinder, a piston acts as the primary moving part. The piston is a short cylindrical component that seals one end of the cylinder. It must seal against the high pressure of the combustion products. To prevent leaks, rings are fitted around the piston's circumference. These rings keep gases from escaping into the crankcase. The gas pressure hits the piston crown, which is the top surface. This force is transferred through the piston web to a gudgeon pin. The pin connects the piston to a connecting rod, which turns the motion into useful work. 
Engineers classify these machines by how they ignite the fuel and how they move. One major group is reciprocating engines, which include two-stroke and four-stroke designs. For example, the Otto cycle is a four-stroke process. Some engines use spark-ignition (SI), which is common in gasoline engines. Others use compression-ignition (CI), which is common in diesel engines. 
History shows a long timeline of discovery for these machines. In 1791, John Barber developed the gas turbine. In 1807, Nicéphore Niépce and Claude Niépce ran a prototype called the Pyréolophore. This engine used controlled dust explosions to power a boat on the Saône river. In 1808, François Isaac de Rivaz invented a hydrogen-based engine using an electric spark. 
Internal combustion engines are used in many different ways today. Most are used in mobile applications like cars, aircraft, and boats. These are often called internal-combustion-engine vehicles (ICEV). In the air, planes might use reciprocating engines or jet engines. Helicopters often use turboshafts, which are gas turbines optimized for torque. On land, engines drive motorcycles, cars, and even locomotives.
Fuel choice is a major part of how these engines function. Most rely on hydrocarbon-based fuels like gasoline, diesel, or natural gas. They can also use renewable fuels. For example, biodiesel is used in compression ignition engines. Bioethanol is used in spark ignition engines. As early as 1900, Rudolf Diesel used peanut oil to run his engines. 
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