Performance Development on Prototype Single-Cylinder Engine: Systematic Combustion System Improvements for Optimum Engine Performance

In recent years, many four-stroke outboard motors have been developed according to the market demand. But four-stroke outboard motor tends to be heavier and larger than conventional two-stroke one due to its more complex mechanism. The outboard motor is required to be light and compact not to disturb the utility of the boat. In addition, boat load requires higher torque at mid engine speed. In such situation, knocking is one of the obstacles against power density. We tried to improve combustion for high power density on a prototype single cylinder engine using up-to-date analyzing and development technology.