Optimization of Turbocharger Characteristics for Personal Watercraft

A suitable turbocharger for PWC 4-stroke engine has been developed by comparing performance tests of various turbocharger components such as turbine sizes, turbine types, and with or without a waste gate. Moreover, to gain higher power at low altitudes while avoiding the overrun of turbocharger, the supercharge pressure at high altitude was controlled by lowering the target supercharge pressure from altitude that overrun occurrence is assumed. The turbocharger characteristics have been achieved suitable for PWC. Indicated Mean Effective Pressure was improved by 40% compared to normally aspirated models and the developed engine realized the compatibility of environmental conformity and higher engine performance.