Effects of fuel injection parameters on performance and emissions formation in a large-bore marine diesel engine

Abstract

Reductions in the emissions of nitrogen oxides (NO x ) and soot from marine diesel engines can be supported by employing multiple-injection strategies, similar to those used in automotive engines. In the present computational study, the possibility of improving the operation of a large two-stroke marine diesel engine at full load by implementing an appropriate pilot injection is explored. A KIVA-3-based computational fluid dynamics code is used, coupled with an evolutionary algorithm. Multi-objective engine optimization is performed by parameterizing the fuel injection profiles in terms of four design variables, which fully define the pilot and main injections. Two objective functions are defined: the final NO x concentration and the specific fuel oil consumption (SFOC), both normalized by the corresponding values of a reference case of continuous injection. Three problem set-ups have been considered: first, an unconstrained problem; second, a problem constrained by the maximum cylinder pressure; third, a problem constrained by both the maximum pressure and the minimum work output per engine cycle. It is found that, in both the unconstrained and the one-constraint problems, the optimum solutions are characterized by substantial improvements in the NO x emissions (of the order of 15-20 per cent) and the SFOC (of the order of 2 per cent). The improvements are less pronounced when both constraints are imposed. A detailed sensitivity analysis of the effects of each of the design variables is presented.

Nitrogen oxide emission calculation for post-Panamax container ships by using engine operation power probability as weighting factor: A slow-steaming case

“…Different types of diesel engines possess various characteristics and potentially different resulting NO x emission factors. At lower loads, the two-stroke main diesel engines tend to experience longer combustion times, lower efficiencies, and lower power outputs and therefore generate relatively large amounts of NO x per unit power, which leads to higher emission factors when compared with high-load operations (Andereadis et al 2011;Corbett and Koehler 2003). This phenomenon is more pronounced for the electrohydraulically controlled large diesel engines and common rail engines that conform to the Tier II regulations.…”

“…To increase the combustion efficiency and adhere to the emission regulations, some manufacturers elevate the maximum explosion pressure and the combustion temperature of engines to reduce fuel oil consumption at low power levels. However, such adjustments increase emissions of NO x (Andereadis et al 2011;Corbett and Koehler 2003).…”

Modelling of temporal and spatial evolution of sulphur oxides and sulphuric acid under large, two-stroke marine engine-like conditions using integrated CFD-chemical kinetics

“…Alternatively, three dimensional (3-D) computational fluid dynamics (CFD) modelling of marine engines is a promising tool to provide a more comprehensive insight into in-cylinder events [19,20]. Nonetheless, several issues have to be addressed beforehand.…”

Effects of Heavy Fuel Oil Blend with Ethanol, n-Butanol or Methanol Bioalcohols on the Spray Characteristics

“…Several commercial software such KIVA, STAR-CD, and AVL FIRE have been developed for studying injection and combustion in diesel engines. Also, many studies related to HFO injection have been conducted by these softwares (Kyriakides et al 2009;Struckmeier et al 2009;Wang et al 2014;Andreadis et al 2011). Despite of these software, open source CFD toolboxes such as OpenFOAM are currently more attractive in the field of fuel injection research.…”