It involves matching of reciprocating engine to rotary compressor and turbine of Turbocharger.
- Impellor of compressor is chosen to provide desired airflow at engine power 80 - 90% MCR , thus taking into account.ie (a) Operating temperature and Engine room pressure (b) Pressure drop across air cooler.
- Once impellor output is fixed , diffuser is chosen which will provide compressor efficiency high , but ample surge margin.
- When compressor side design is final , turbine power requirements are known.
- The main variable on the turbine side is nozzle size and this is matched to provide required compressor work and minimum restriction to exhaust gas flow.
- Smaller nozzle area: (a)Work output increase (b) T\C speed increase (c) Air delivery pressure increase