함정용 디젤엔진의 밀러 사이클 최적화에 관한 연구

Abstract

Since May 2005, all ocean-going vessels built after January 2000 have had to comply with the emission control regulations according to Annex Ⅵ of the MARPOL 73/78 convention. Thesse regulations set limits on exhaust gas emissions for nitrogen oxides(NOx), sulphur oxides(SOx) and particulate matter(PM) from ships.

The air pollutants as NOx, SOx, PM etc are harmful things for human health. They can be obsorbed onto the lung and cause lung disease like a lung cancer.

And they are blamed as one of the major causes of photochemical smog and acid rains.

The NOx emission is related with engine combustion process as like high peak pressure, high compression ratio, high rate of fuel delivery. In other words, the

higher combustion temperature, the grater amount of NOx formation. Much of NOx emission can be decreased by the technology today. For example the fuel injection control by CR(Common Rail) and electronic control, EGR(Exhaust Gas Recirculation), SCR(Selective Catalytic Reduction) which using ammonia or urea, Miller Cycle and 2-stage turbocharging, etc.

Miller Cycle is one of the few measures that can be applied in an internal combustion engine to simultaneously reduce NOx emission and fuel consumption.

Since all engine builders strive to meet engine emission limits without any loss of efficiency, practically every modern engine is operated today with at least moderate Miller timing.

In this study, a performance simulation about naval vessel diesel engine carried out through a mathematical modeling techniques for flow analysis of the working

gas. And the simulation results were compared with measured data to evaluate reliability of simulation. Finally we obtained reliable simulation results.

The purpose of this study is to predict effect of miller cycle for naval vessel diesel engine. By changing the intake valve closing timing and boost pressure,

the engine performance is simulated. And we found the best valve timing and proper boost pressure.