device converting energy into mechanical work
types: internal combustion (gasoline, diesel), electric motor, steam, jet, rocket
internal combustion: fuel-air mixture ignites in cylinders, drives pistons and crankshaft
electric motor: electromagnetic interaction between stator and rotor, high efficiency
steam engine: heat boils water, expanding steam drives piston or turbine
jet engine: continuous combustion, thrust from exhaust gas acceleration
efficiency measured as ratio of useful work to input energy
powers transport, pump systems, generators, industrial machinery
electrification of engines is the core transition of the 21st century energy system
battery and semiconductor controls enable modern electric drivetrains