A Numerical Study on Combustion and Emission Characteristics of a Medium-Speed Diesel Engine Using In-Cylinder Cleaning Technologies

Abstract

Abstract:In order to clarify the potential of internal purification methods on medium speed diesel engines to meet the IMO Tier III nitrogen oxide (NOx) emission regulations, combined 1-D engine working cycle simulation and 3-D CFD simulation were conducted to predict the performance and emissions of the engine under different valve close timings, geometric compression ratios, injection timings, and Exhaust Gas Recirculation (EGR) rates. The numerical results show that, as the inlet valve close timing is advanced, NOx is reduced by as much as 27%, but the peak of premixed combustion heat release rate is increased; this can weaken the ability to reduce NOx with the Miller cycle. Moreover, the peak of premixed combustion heat release rate is reduced when the geometric compression ratio is increased to 15.4, and linking with injection timing by delaying 6°CA can further reduce NOx by 55.3% from the baseline. Finally, over 80% NOx reduction can be achieved when the above schemes are combined with over 15% EGR. The NOx and soot can be reduced simultaneously by using moderate Miller cycle combination with moderate EGR, and the results show a large reduction of NOx and moderate reduction of soot. This can be a feasible technical solution to meet Tier III regulations.

Effects of a Dual-Loop Exhaust Gas Recirculation System and Variable Nozzle Turbine Control on the Operating Parameters of an Automotive Diesel Engine

“…Other aspects are related to the integration of EGR circuits with the main engine sub-assemblies, such as fuel injection equipment [8,9] and turbocharging systems [10], either in a single-stage configuration fitted with variable nozzle turbine (VNT) [11] or according to two-stage concepts [12]. Moreover, other available cleaning options have to be matched to EGR, such as Miller cycle [13] or advanced combustion processes [14,15], extending its use to the whole range of ICEs, such as in marine and stationary applications. Finally, the growing interest in alternative fuels, is leading to further issues to be deepened [16][17][18].…”

A 1D–3D Approach for Fast Numerical Analysis of the Flow Characteristics of a Diesel Engine Exhaust Gas

“…The 1D CFD model used AVL Boost software to simulate the engine working cycle, and the 3D CFD model used AVL Fire software. The method of combining 1D and 3D used a function built into the software [15]. Millo et al analyzed the gas flow in the cylinder of the diesel engine by combining the 1D commercial code GT-SUITE and the 3D commercial code CONVERGE CFD.…”

Parametric investigation of pre-injection on the combustion, knocking and emissions behaviour of a large marine four-stroke dual-fuel engine

“…However, fewer studies have been conducted on the laws of influence of pre-injection parameters on knock, combustion and emissions, and methods to optimize pre-injection parameters, especially in the field of marine medium speed large-bore DF engine [31,34]. Due to the large size of marine DF engines, it is difficult to carry out relevant experiments [27,35,36]. The numerical simulations have been widely accepted as the best way and partial alternative to the research of large marine engines [3,37].…”