3.2.4. Free piston compressor

<BR>The free piston compressor belongs to the family of displacement compressors.

It is a compressor with an integrated two-stroke diesel engine.

Compressed air acts on the raised pistons and pushes them back inside, thereby starting the compressor. The combustion air thus compressed in the engine cylinder drives the pistons apart again upon combustion of the injected fuel. The enclosed air is compressed. After letting out the necessary scavenging air the greater part of the compacted air is pushed out through a pressure holding valve. Any remaining air is pushed back in by the piston for the new cycle. The induction valves draw in new air again.
Fig. 3.9: Op. diagram of free piston compressor
    • Highly efficient.
    • Smooth-running.
    • Simple principle, but seldom used.
      In practice, the piston movements need to be synchronised and extensive control equipment fitted.