Yoshimasa Hayashi

Analytical study on engine noise caused by vibration of the cylinder block and crankshaft

To clarify the mechanism of torsional and lateral bending vibration of the cylinder block which has a large affect on engine noise, an analysis was conducted of the influence of crankshaft torsional vibration on cylinder block vibrations. There were two main results. The first is that the lateral forced vibration of the crankshaft by the fluctuation of the lateral inertia force generated with the torsional vibration of the crankshaft directly causes the vibrations of the cylinder block. The other is that the level of cylinder block vibration varies according to the condition in which the frequency of the fluctuation of inertia force approaches the resonant frequencies of the cylinder block. Further, noise reduction can be achieved by optimizing the resonant frequency of the crankshaft torsional vibration.

The Development of Engine Evaporative Cooling System

A fundamental heat transfer study has been conducted on a new engine cooling system in which heat is removed from the engine through the boiling process in the water jacket and is radiated to the air through a condenser. By carrying out a basic experiment using a model boiler as a substitute for the cylinder heat water jacket and a real engine experiment, the following cooling system characteristics were found: First, a good heat transfer coefficient can be obtained up to an order of 10/sup 3/ kw/m/sup 2/ heat flow with only a small coolant flow. Second, it is possible to obtain a more uniform temperature distribution over the engine structure by making use of the cooling by boiling characteristics which remove more heat from hotter surfaces than from cooler ones. Third, the good response of this systems variable temperature control procedure greatly reduces knocking, which in turn increases power.