2016 年 82 巻 835 号 p. 15-00542
This paper describes the results of supercharging applied for dual fuel diesel combustion using natural gas (CNG) induced from an intake pipe. The boost pressures were varied from 98 kPa (naturally aspirated condition) to 140 kPa with a Roots blower type supercharger driven by an inverter controlled motor. The influence of boost pressures on the engine performance, combustion characteristics, and emissions were investigated and are compared with ordinary diesel combustion. The results showed opposite effects of changes in the boost pressure on the emission characteristics and brake thermal efficiency for the dual fuel diesel combustion and ordinary diesel combustion. In ordinary diesel operation, the brake thermal efficiency increased remarkably with increasing boost pressures due to the significant reductions in smoke and CO emissions, specifically at high load conditions. For the dual fuel diesel operation, the brake thermal efficiency decreased with increasing boost pressures and with increasing CNG supply due to the significant increases in HC and CO emissions.
