Dynamics and Control of a Free-Piston Diesel Engine

Free-piston diesel engines are characterized by freely moving pistons without any crankshaft or camshaft connected to the pistons. This allows a compact and efficient engine design, but requires automatic control of the piston motion. This paper present a dynamic mathematical model of a free-piston diesel engine, and a control oriented dynamic analysis leading to a piston motion control structure. Experimental results using a full scale test cylinder are included and show feasibility of the suggested control approach.