A sampling system with a variable pressure check valve was designed to investigate the combustion efficiency of pulse detonation combustion process on the basis of the pulse detonation engine(PDE) operating principle analysis.With the designed sampling system

the combustion efficiencies of the pulse detonation combustion processes using gasoline as fuel and compressed air as oxidizers at operating frequency of 5 Hz were measured both at conditions that the steady and fully developed detonation waves were formed and not formed.The experimental results indicate that the pulse detonation combustion efficiency can be measured successfully using the designed sampling system.The combustion efficiency where the detonation waves have fully developed is higher than that of not fully developed. The highest combustion efficiency is up to 99.6%.