Pressure-wave　supercharger　(PWS)　is　a　technical　way　to　raise　engine　intake　pressure.　In　this　research,　a　compression-ignition　(CI)　engine　is　boosted　by　COMPREX　PWS　and　the　performance　of　the　engine　was　tested.　In　order　to　improve　the　power　of　the　PWS　diesel　engine,　the　Grey　Relational　Analysis　was　completed.　The　analysis　results　show　that　two　factors,　the　intake　air　flow　and　the　exhaust　gas　temperature,　have　the　most　important　influences　on　the　PWS　engine　power.　Thus　the　volume　of　the　intake　manifold　is　enlarged　to　increase　intake　air　flow　while　the　exhaust　manifold　is　wrapped　by　asbestos　with　an　iron　cover　to　preserve　the　high　exhaust　gas　temperature.　Consequently,　the　final　experimental　results　show　that　both　the　power　and　the　torque　have　been　built　up　as　well　as　excellent　fast　response　to　various　load.　Together　with　experimental　test,　the　Computational　fluid　dynamic　(CFD)　simulation　was　completed　based　on　a　three-dimensional　(3D)　model　of　the　PWS　rotor　channel.　The　CFD　simulation　shows　that　the　inner　exhaust　gas　recirculation　(EGR)　phenomenon　happens　especially　at　middle　PWS　rotational　speed　with　30%　of　full　load.　The　test　results　demonstrate　that　the　PWS　diesel　engine　performs　better　with　less　NOx　and　soot　emissions.　(C)　2009　Elsevier　Ltd.　All　rights　reserved.