Studies on combustion, vibration, and noise in high-speed diesel engines through newly developed measuring instruments

The authors have been conducting studies on the reduction of exhaust emissions using a high-speed diesel engine. By applying composite countermeasures consisting of five items: (1) timing retard, (2) optimization of fuel injection system, (3) waterin- oil type emulsifiedfuel, (4) application of ignition improver, and (5) an increase in airflow quantity, an exhaustNO_x level less than half of the original was attained while retaining the original low levels of fuel consumption, smoke density, and engine noise. The authors developed new measuring instruments in order to grasp the true nature of combustion, especially to clarify the delicate change incombustion. By using these instruments, the combustion phenomena were analyzed accurately, speedily, and synthetically on various aspects such as combustion mode, vibration, noise, thermal loading, heat balance, etc. The complicated combustion behavior in the cylinder has been clarified in part by simultaneous measurement of cylinder pressure at several points.