original question: Which engine category has sub-categories like [Pulsejet]?
answer: reaction engine
answer type: Engine category.
auxiliary information: A pulsejet engine is a type of jet engine in which combustion occurs in pulses. Pulsejet engines can be made with few or no moving parts, and are capable of running statically. Pulsejet engines are a lightweight form of jet propulsion, but usually have a poor compression ratio, and hence give a low specific impulse. One notable line of research of pulsejet engines includes the pulse detonation engine which involves repeated detonations in the engine, and which can potentially give high compression and good efficiency.
[Pulsejet] is a sub-category belonging to which engine category?