Parameters coupling designation of diesel free-piston linear alternator

This research presents a novel parameters coupling designation method of diesel free-piston linear alternator. The relationship between the main parameters of linear alternator and free-piston engine is built up based on the energy conservation relationship between these two devices. An iterative procedure is carried out among the zero-dimensional numerical simulation of the free-piston linear alternator, CFD calculation of the gas exchanging process and combustion process of the free-piston engine to define the main geometric dimensions of the free-piston engine. A starting method of using the resonance characteristics of free-piston engine is simulated with different relatively small constant thrust forces and the designed free-piston engine could be started by the linear alternator. The results indicate that the load of the linear alternator is primarily associated with the bore of the engine, and the maximum electromagnetic force is approximately proportional to the square of the bore; the effective stroke length is associated with the optimum working point of free-piston linear alternator which could be defined using the numerical simulation program.

► Parameters coupling relationship of FPE and linear alternator is built up.
► The main dimensions of FPE is defined using an iteration procedure.
► The max. electromagnetic force is almost proportional to the square of the bore.
► The FPLA can be started with small starting force using its resonance characteristic.
► Long effective stroke helps increase the compression ratio and efficiency of FPE.