Studies on combustion, vibration and noise in high speed diesel engine 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) water-in-oil type emulsified fuel, 4) application of ignition improver and 5) an increase in air flow quantity, an exhaust NOx level less than a 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 in combustion. 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.