Performance analysis of a free piston engine

Date of Award




Degree Name

Doctor of Philosophy (Ph.D.)

First Committee Member

Michael Swain - Committee Chair


The performance of a free piston engine was evaluated and modeled using a single shot combustion experiment. The investigation was in the areas of efficiency, exhaust emissions, combustion duration, energy input required to initiate combustion, ignition temperature, ignition pressure, ignition compression ratio, and cylinder volume change during combustion. Four hundred and eighty experiments with eleven different fuels were performed. A constant volume combustion theoretical model was used to compare to the experimental results. It was found that this type of engine offers advantages in the areas of higher indicated thermal efficiency, lower exhaust emissions and is able to more closely match ideal Otto cycle performance than a conventional crankshaft engine. This research was conducted at Sandia National Laboratory and encompasses the material presented in SAND Report 99-8206 and the 1998 SAE paper 982484 Homogeneous Charge Compression ignition with a Free Piston Engine: A New Approach to Ideal Otto Cycle Performance which was awarded the 1998 SAE Horning Award for excellence in technical research. This research was supported by The Department of Energy, Office of Solar Thermal, Biomass Power and Hydrogen Technologies, and Sandia National Laboratory's Laboratory Directed Research and Development Program.


Engineering, Automotive; Engineering, Mechanical

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