How Cars Work

Currently the most common propulsion system in an automobile is the internal combustion engine (ICE). ICEs burn fuel in a combustion chamber inside the engine. Examples include the four-stroke, two-stroke, rotary, and gas turbine engines. The four-stroke internal combustion engine (also known as the Otto cycle, named after Nikolaus Otto) is the most common type used in automobiles. In a four-stroke engine the piston makes reciprocating (back and forth or up and down) movements to convert the chemical energy of fuel into mechanical energy of motion (kinetic energy). Spark ignition engines are fueled by gasoline, propane, natural gas, or gasoline/alcohol blend. Compression ignition engines are fueled by diesel. This section focuses on: