디젤엔진의 압축천연가스/디젤 혼합율과 커먼레일압력에 따른 배기특성 분석

Abstract

Today, regulations on air pollution are gradually being strengthened. For diesel engines, EURO 6 regulates a nitrogen oxides (NOx), carbon dioxide (CO2), and particulate matter (PM). Currently commercialized diesel engines must be used in accordance with this regulation, so research on diesel engines using dual fuels is more active than diesel engines using single fuel. In this experiment, a 2000 cc four-cylinder diesel engine was operated at 11,7 kW, 23.4 kW and 35.1 kW engine loads, and the common rail pressure at each load was changed to 50 MPa, 60 MPa, 70 MPa and 80 MPa to study the exhaust characteristics according to the mixing ratio of compressed natural gas and diesel oil. As a result of the experiment, the maximum heat release rate and the maximum pressure in the cylinder showed a proportional relationship with the increase in the natural gas mixing rate, and the post-combustion period increased as the natural gas mixing rate increased at each load. The ignition time was advanced as the common rail pressure increased at each load. There was no significant change in the amount of NOx generated when natural gas was mixed than that of diesel, but the amount of CO2 was significantly reduced. When the natural gas mass ratio increased, the amount of CO generated tended to decrease, and the amount of THC generated increased only at 11.7 kW and did not change significantly at other loads. In the change of the common rail pressure, the higher the common rail pressure, the higher the NOx and CO2 generation was at 23.4 kW than 11.7 kW, but the CO generation was 11.7 kW and 23.4 kW. The amount of CO2 generated was slightly higher when the common rail pressure was higher than when it was low. The amount of THC generated was hardly affected by the common rail pressure.