LTC (Low Temperature Combustion)
Background: Internal Combustion Engines are primary power sources of the commercial vehicles. But its hazardous emissions threaten our health. Especially in diesel engines, high level of nitrogen oxides (NOx) and particulate matter (PM) emissions are serious problems which should be solved. Therefore, recent researches about diesel engines have been ?focused on low temperature combustion (LTC), which simultaneously reduces NOx and PM emissions.
Basic concept of LTC
Exhaust gas recirculation (EGR) was widely used to reduce NOx emission by diluting the intake air. However, it caused relatively higher PM emissions. (Trade-off between NOx and PM)
Recently, Akihama et al. reported that simultaneous reduction of NOx and PM can be achieved at low temperature combustion regions. Low temperature combustion can be realized when the high level of EGR is supplied to the combustion chamber.
LTC has some problems to be commercialized. These problems are high level of CO and HC emissions compared to the conventional diesel engines and the limitation of high load driving.
▲ Fuel spray characteristics according to the fuel injection equipment (FIE)
- spray pattern
- spray characteristics(penetration, angle, atomization)
- injection rate
▲ Power output, Exhaust emission, Fuel economy characteristics according to the engine operating conditions in 5-cylinders and direct injection (DI) diesel engine
- Injection timing
- Injection pressure
- EGR rate