廃食油バイオディーゼル燃料の直噴式ディーゼル機関適用化研究

―第1報機関性能および燃焼・排気特性

抄録

The combustion and emission characteristics for two waste cooking oils were investigated in detail. One fuel was the methyl esters in waste cooking oil. This fuel is in routine use in Kyoto City for a garbage collection vehicle with DI diesel engine (B100) and a city bus (B20; 80% by volume gas oil is mixed into B100) as an alternative fuel for gas oil. The other is fuel created by removing impurities from raw waste cooking oils. In order to improve the fuel properties, kerosene is mixed 70% by volume in this fuel. The mixed fuel (i-BDF) is used in several trucks in Wakayama City.
In the experiments, the engine performance and exhaust emissions were investigated in a single-cylinder, direct injection diesel engine. As a result, NO_x emissions are similar for both fuels. PM emissions are lower for waste cooking oil methyl esters than for other fuel at a wide range of engine loads. The combustion characteristics in the cylinder were investigated by an optical method. The luminous intensity, which might correspond to soot, near the injection nozzle was reduced for the waste cooking oil methyl esters operation.