How many units does a civil aircraft have?

Civil aviation aircraft are generally equipped with 2-4 engines, all of which work at the same time.

At present, the traditional aero-engine is developing to gear transmission engine, variable cycle engine, multi-electric engine, intercooled regenerative engine and open rotor engine. Non-traditional pulse detonation engines, transcendental ramjet engines, combined engines based on turbines, solar power generation and fuel cell power generation are also maturing. The development of these engines will make the future aircraft faster, higher, farther, more economical and more reliable, and meet the stricter environmental protection requirements, which will be superb.