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

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.

Marine Power Systems

“…Pelić et al [4] discussed the medium-speed diesel engine in diesel-electric propulsion systems, which is increasingly used as the propulsion engine for liquefied natural gas (LNG) ships and passenger ships. The main advantage of such systems is their high reliability, better maneuverability, greater ability to optimize and significant decrease in the engine room volume.…”

“…Although maritime transport is pointed to as an energy-efficient mode of transportation, its emission of GHGs is still high despite new technologies that have been adopted [1]. Optimization and the use of new fuels with new technologies for power generation of such systems are always tasks that are necessary in order to improve efficiency of the power generation system and to reduce GHG emissions [2][3][4][5][6].…”

Comparative Assessment and Parametric Optimisation of Large Marine Two-Stroke Engines with Exhaust Gas Recirculation and Alternative Turbocharging Systems

“…With the development of electronically controlled injection systems for diesel engines, multiple injections, as well as the precise control of injection timings and injected fuel amounts, have been realised [9]. Several studies have focused on the optimisation of injection strategies such as pilot injection [10,11], split injection [12,13], injection timing [14,15], and injection pressure [16]. Their results demonstrate that the fuel injection strategy optimisation is not sufficient to enable the engine to meet the TIII limits due to its limited capability of NOx emissions reduction.…”

Impact of Compressed Natural Gas (CNG) Fuel Systems in Small Engine Wood Chippers on Exhaust Emissions and Fuel Consumption

“…This fuel in maritime transport is a transitional fuel in the decarbonisation of maritime transport [19]. In ship engine designs, the use of LNG fuel may limit NO x [20]. However, the level of NO x emission is strongly related to the efficiency level of the drive unit [20].…”

“…In ship engine designs, the use of LNG fuel may limit NO x [20]. However, the level of NO x emission is strongly related to the efficiency level of the drive unit [20]. Other studies on LNG-powered ships show a reduction in fuel consumption, CO 2 and NO x emissions compared to traditional fuel (diesel), while at the same time causing higher HC emissions than traditional fuels [21].…”