Based on the structure characteristics of the ROTAX914 carburetor piston aviation engine

a single-cylinder low pressure air-assisted direct injection aviation testing engine was developed. The influences of different controlling parameters

including injection timing

injection duration

injection pressure

ignition advance angles

on the combustion characteristics of the engine were investigated. The results show that: the engine combustion efficiency gets higher and the combustion cyclic variations get lower at the optimal start injection. With the increase of engine speed and load

the optimal start of injection is advanced accordingly. With the decrease of the direct injection duration and the injection pressure

the peak cylinder pressure and the rate of pressure rise are reduced

the rapid combustion period is extended and the combustion cyclic variations get higher. With the advancing of the ignition time

the peak cylinder pressure and the rate of pressure rise are increased

the combustion phase gets earlier and the combustion cyclic variations are reduced.