Analysis of the Impact of Split Injection on Fuel Consumption and NOx Emissions of Marine Medium-Speed Diesel Engine

Vladimir Pelić,Tomislav Mrakovčić,Marko Valčić,Radoslav Radonja

doi:10.3390/jmse8100820

Vladimir Pelić, Tomislav Mrakovčić

Open Access

https://doi.org/10.3390/jmse8100820

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Abstract

The medium-speed diesel engine in diesel-electric propulsion systems is increasingly used as the propulsion engine for liquefied natural gas (LNG) ships and passenger ships. The main advantage of such systems is high reliability, better maneuverability, greater ability to optimize and significant decreasing of the engine room volume. Marine propulsion systems are required to be as energy efficient as possible and to meet environmental protection standards. This paper analyzes the impact of split injection on fuel consumption and NOx emissions of marine medium-speed diesel engines. For the needs of the research, a zero-dimensional, two-zone numerical model of a diesel engine was developed. Model based on the extended Zeldovich mechanism was applied to predict NOx emissions. The validation of the numerical model was performed by comparing operating parameters of the basic engine with data from engine manufacturers and data from sea trials of a ship with diesel-electric propulsion. The applicability of the numerical model was confirmed by comparing the obtained values for pressure, temperature and fuel consumption. The operation of the engine that drives synchronous generator was simulated under stationary conditions for three operating points and nine injection schemes. The values obtained for fuel consumption and NOx emissions for different fuel injection schemes indicate the possibility of a significant reduction in NOx emissions but with a reduction in efficiency. The results showed that split injection with a smaller amount of pilot fuel injected and a smaller angle between the two injection allow a moderate reduction in NOx emissions without a significant reduction in efficiency. The application of split injection schemes that allow significant reductions in NOx emissions lead to a reduction in engine efficiency.

Highlights

Energy efficiency and environmental friendliness are the basic criteria when choosing the optimal technology in any industry, so this is the case with the transport of goods
Marine propulsion systems are required to be as energy efficient as possible and to meet environmental protection standards
This paper analyzes the impact of split injection on fuel consumption and NOx emissions of marine medium-speed diesel engines

Summary

Introduction

Energy efficiency and environmental friendliness are the basic criteria when choosing the optimal technology in any industry, so this is the case with the transport of goods. While the research in these papers describes in detail different models of internal combustion engines to simulate nitrogen oxide emissions, few or no investigate the impact of split fuel injection with application to marine medium-speed diesel engines of 5000 kW and more. The aim of this paper is to examine the impact of different split fuel injection schemes on the specific fuel consumption and nitrogen oxide emissions of a marine medium-speed diesel engine using a two zone combustion numerical model

Numerical

Mass Conservation Law

Energy Conservation Law

Indicated Work

Heat Exchange

Heat Release

Change in Mass And Excess Air in The Cylinder

Working Medium Exchange in A 4-Stroke Engine Cylinder

Turbocharger

Effective Engine Power

Two-Zone Numerical Sub-Model

Formation