An experimental study on the working characteristics of a single piston hydraulic free-piston diesel engine

The working characteristics of the principle prototype of a single piston hydraulic free-piston diesel engine (HFPDE) are studied. The results indicate that the piston dynamics of HFPDE differs from those of conventional engines, and the frequency of piston movement can be controlled and hence the power can be adjusted by changing the dwelling time of piston at the bottom dead center. The main combustion phase in HPFDE is rapid combustion phase, in which most of the fuel burns, resulting in higher rate of heat release. The responsibility of suction and discharge valves in pump chamber has certain effects on the building up process of pump chamber pressure. Raising their responsibility can improve combustion, increase hydraulic power output and enhance the efficiency of HFPDE.