An experimental analysis of low-temperature and premixed combustion for simultaneous reduction of NO_x and particulate emissions in direct injection diesel engines

Abstract

A new combustion concept, named MK (modulated kinetics) combustion, has been developed, which reduces NOx and smoke simultaneously through high exhaust gas recirculation (EGR) and retarded injection timing. High-speed photography was employed to investigate the physical and chemical processes of MK combustion, and the results revealed that the combustion features premixed combustion and the low-temperature flames were accompanied by transparent appearances. Heat flux measurements and KIVA calculations were also made to investigate the effects of swirl, which serves to improve thermal efficiency in MK combustion. It was apparent that the swirl effectively governs the fuel distribution in the combustion chamber, suppressing HC formation and improving thermal efficiency by preventing the flames from contacting the cavity walls. Throughout these experiments, ignition delay and fuel injection duration were found to be the two key parameters that control MK combustion. Accordingly, ignition delay was prolonged by cooled EGR and fuel injection duration was shortened by high injection pressure to allow the MK combustion operation in a high load range.

Analysis of the combustion process, pollutant emissions and efficiency of an innovative 2-stroke HSDI engine designed for automotive applications

“…Previous research works on advanced combustion concepts with high degree of premixing and low oxygen concentration, such as HCCI [1], PCCI [2][3] and LTC [4] combustions, confirmed how it is possible to decrease down to near to zero values NO X and soot levels simultaneously [5].…”

“…Gas temperature at the start of injection of the pilot injection VVT Variable Valve Timing YO 2 Oxygen concentration in the cylinder YO 2 atm Atmospheric oxygen concentration YO 2 …”

Modeling of Common Rail System and Constant Volume Chamber in Biodiesel Combustion: A Review

“…However, activated combustion increases NO x and combustion noise. It was commonly believed that the purpose of high injection pressure was the reduction of PM and the injection timing was retarded so as to reduce NO x [22]. .…”

Control -Oriented Modeling and Experimental Study on Low Temperature Combustion for Diesel Engine

“…In order to meet the increasingly stringent emission regulations, the diesel engine LTC has been widely investigated in recent years [1][2][3][4]. By controlling the fuel injection, exhaust gas recirculation (EGR) and variable geometry exhaust gas turbocharger (VGT), improving the mixing rate of air and fuel, reduction of combustion temperature and intake oxygen concentration could be achieved, which could simultaneously lower the emission of nitrogen oxides (NOx) and soot.…”