In February 1999, the International Academy of Engineering convened an expert panel to select the technologically outstanding achievements of the 2O” century & its no surprise that the I.C. Engine Technology topped the list. But, Pollution concerns, global warming and shrinking fossil fuel reserves have focused world attention on how engines generate electrical and mechanical power in a better way.

“The free piston engine is an attempt to combine the high thermal efficiency of a reciprocating engine with high power/weight ratio of a rotary turbine. It is a combination of a reciprocating engine and a rotary turbine.

The quest for increased power from a given cylinder size has resulted in a long process of development. Important steps in this process of development are improvements in the fuels used and in the design of various components for higher efficiencies and lower cost and weight. However, a different approach in the direction of using different cycles of operation or modifications of existing cycle, has also been pursued with great interest.”

In a step towards exploiting existing power cycles, scientists at the U.S Department of Energy’s Los Alamos National Laboratory have developed a remarkably simple, energy-efficient engine which works on Stirling Cycle and has no oscillating pistons, oil seals or lubricants, known as the

“Thermoacoustic Stirling Engine”.

Sound waves in “thermoacoustic” engines can replace the pistons and cranks that are typically built into conventional engines & hence in true sense thermoacoustic stirling engine can be termed as advancement in free piston engines.