The process of starting the chemical reaction of a fuel-air mixture to release thermal energy. In spark-ignition engines, this requires a high-voltage electrical arc across a spark plug. In compression-ignition engines, it occurs spontaneously when fuel is injected into highly compressed, superheated air.
Heard on the job
We have fuel and air, but no ignition, so check the coil packs.
Related terms
Cylinder
The tubular chamber in which a piston travels to compress a fluid or convert fluid pressure into mechanical work.
Two-stroke
Describing an engine that completes a power cycle in just one upward and one downward piston movement.
Power
The rate at which work is done or energy is transferred over time.