scholarly journals A Numerical Study on the Combustion Process and Emission Characteristics of a Natural Gas-Diesel Dual-Fuel Marine Engine at Full Load

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1342
Author(s):  
Van Chien Pham ◽  
Jae-Hyuk Choi ◽  
Beom-Seok Rho ◽  
Jun-Soo Kim ◽  
Kyunam Park ◽  
...  
Keyword(s):  
Natural Gas ◽  
Combustion Process ◽  
Simulation Software ◽  
Dual Fuel ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Cylinder Pressure ◽  
Marine Engine ◽  
Full Load ◽  
Simulation Results

This paper presents research on the combustion and emission characteristics of a four-stroke Natural gas–Diesel dual-fuel marine engine at full load. The AVL FIRE R2018a (AVL List GmbH, Graz, Austria) simulation software was used to conduct three-dimensional simulations of the combustion process and emission formations inside the engine cylinder in both diesel and dual-fuel mode to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results were then compared and showed a good agreement with the measured values reported in the engine’s shop test technical data. The simulation results showed reductions in the in-cylinder pressure and temperature peaks by 1.7% and 6.75%, while NO, soot, CO, and CO2 emissions were reduced up to 96%, 96%, 86%, and 15.9%, respectively, in the dual-fuel mode in comparison with the diesel mode. The results also show better and more uniform combustion at the late stage of the combustions inside the cylinder when operating the engine in the dual-fuel mode. Analyzing the emission characteristics and the engine performance when the injection timing varies shows that, operating the engine in the dual-fuel mode with an injection timing of 12 crank angle degrees before the top dead center is the best solution to reduce emissions while keeping the optimal engine power.

scholarly journals Effects of Various Fuels on Combustion and Emission Characteristics of a Four-Stroke Dual-Fuel Marine Engine

2021 ◽  
Vol 9 (10) ◽  
pp. 1072
Author(s):  
Van Chien Pham ◽  
Beom-Seok Rho ◽  
Jun-Soo Kim ◽  
Won-Ju Lee ◽  
Jae-Hyuk Choi
Keyword(s):  
Alternative Fuels ◽  
Numerical Study ◽  
Combustion Process ◽  
Simulation Software ◽  
Dual Fuel ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Marine Engine ◽  
Adjustment Method ◽  
Simulation Results

A numerical study was carried out to investigate the effects of methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), and dimethyl ether (DME) on the combustion and emission characteristics of a four-stroke gas-diesel dual-fuel (DF) marine engine at full load. Three-dimensional simulations of the combustion process and emission formation inside the engine cylinder in the diesel and DF modes were performed using the AVL FIRE R2018a simulation software to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results agreed well with the measured values reported in the engine shop test technical data. The simulation results showed reductions in the in-cylinder peak pressure and temperatures, as well as the emission formations, in the DF modes in comparison to the diesel mode. The DF mode could significantly reduce nitric oxide (NO) emissions (up to 96.225%) of DME compared to the diesel mode. Meanwhile, C3H8 and CH4 fuels effectively reduced the soot (up to 82.78%) and carbon dioxide (CO2) emissions (by 21.33%), respectively, compared to the diesel mode. However, the results also showed longer ignition delay times of the combustion processes when the engine operated in the DF mode, particularly in the DME-diesel mode. The combustion and emission characteristics of the engine were also analyzed when varying the injection timing; the results showed that applying the injection timing adjustment method could further address NO emission problems but led to a decrease in the engine power. Therefore, it is necessary to consider the benefits and disadvantages of adopting the injection timing adjustment strategy to address certain engine emission problems. This study successfully analyzed the benefits of using various gas fuels as alternative fuels and the injection timing adjustment method in DF marine engines to meet the International Maritime Organization (IMO) emission regulations without the use of any emission after-treatment devices.

scholarly journals Effects of the Multiple Injection Strategy on Combustion and Emission Characteristics of a Two-Stroke Marine Engine

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6821
Author(s):  
Ju-Hwan Seol ◽  
Van Chien Pham ◽  
Won-Ju Lee
Keyword(s):  
Single Injection ◽  
Simulation Software ◽  
Emission Characteristics ◽  
Cylinder Pressure ◽  
Multiple Injection ◽  
Injection Strategy ◽  
Marine Engine ◽  
Injection Mode ◽  
Double Injection ◽  
Simulation Results

This paper presents research on the effects of the multiple injection strategies on the combustion and emission characteristics of a two-stroke heavy-duty marine engine at full load. The ANSYS FLUENT simulation software was used to conduct three-dimensional simulations of the combustion process and emission formations inside the engine cylinder in both single- and double-injection modes to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results were then compared and showed good agreement with the measured values reported in the engine’s sea-trial technical reports. The simulation results showed reductions in the in-cylinder pressure and temperature peaks by 6.42% and 12.76%, while NO and soot emissions were reduced up to 24.16% and 68%, respectively, in the double-injection mode in comparison with the single-injection mode. However, the double-injection strategy increased the CO2 emission (7.58%) and ISFOC (23.55%) compared to the single-injection. These are negative effects of the double-injection strategy on the engine that the operators need to take into consideration. The results were in line with the literature reviews and would be good material for operators who want to reduce the engine exhaust gas emission in order to meet the stricter IMO emission regulations.

Simulation Research on Combustion Process in a Natural Gas-Diesel Dual-Fuel Marine Engine

2014 ◽  
Vol 525 ◽  
pp. 227-231 ◽  
Author(s):  
Min Xiao ◽  
Chun Long Feng
Keyword(s):  
Natural Gas ◽  
Total Energy ◽  
Combustion Process ◽  
Power Reduction ◽  
Dual Fuel ◽  
Injection Timing ◽  
Simulation Research ◽  
Injection Duration ◽  
Medium Speed ◽  
The Right

In order to solve the problem of Diesel natural gas dual fuel engine, such as power reduction, low charging efficiency, the conception of diesel engine fueled with pilot-ignited directly-injected liquefied natural gas is put forward. On the basis of this theory, a medium speed diesel of the marine is refitted into dual fuel engine, in order to keep original power, decrease the temperature of combustion and reduce emission. The LNG injection timing, duration of LNG injection and the different ratios the pilot diesel to total energy are studied the method of AVL FIRE software. Conclusions are as follows: When the different ratios pilot diesel to total energy is 0.5%, the engine can not work; Delaying the LNG injection timing, shortening the LNG injection duration and choose the right ratios pilot diesel to total energy can reach the indicated power of original machine, and the NOx emissions level will be greatly reduced.

scholarly journals Effect of hydrogen addition in diesel/natural gas dual-fuel combustion with late injection

2021 ◽  
Vol 312 ◽  
pp. 08005
Author(s):  
Antonio Caricato ◽  
Antonio Paolo Carlucci ◽  
Antonio Ficarella ◽  
Luciano Strafella
Keyword(s):  
Natural Gas ◽  
Conversion Efficiency ◽  
Early Stage ◽  
Combustion Process ◽  
Pollutant Emission ◽  
Dual Fuel ◽  
Injection Timing ◽  
Pilot Injection ◽  
Fuel Conversion ◽  
Hydrogen Addition

In a previous work, the effectiveness of late pilot injection on improving combustion behaviour – in terms of fuel conversion efficiency and pollutant emission levels – in a diesel/natural gas dual-fuel engine was assessed. Then, an additional set of experiments was performed, aiming at speeding up the combustion process possibly without penalizing NOx levels. Therefore, hydrogen was added to natural gas in a percentage equal to 10%. Results show that hydrogen addition has a significant effect on the combustion development specially during the early stage of combustion: ignition delay is shortened and combustion centre is advanced, while the combustion duration increases when pilot injection timing is set to conventional values, while remains basically unchanged for late timings. Fuel conversion efficiency is only slightly penalized when hydrogen is added. Moreover, it was confirmed that, in general, combustion strategy with late pilot injection timing does not penalize fuel conversion efficiency; indeed, in some cases, it actually increases. Concerning regulated emission levels, it is again proven that late pilot injection does not penalize pollutant production: the hydrocarbons and carbon monoxide reduce as pilot injection is delayed, probably due to the higher temperatures reached into the cylinder during most part of the expansion stroke. Moreover, adding hydrogen always reduces their levels. Concerning NOx, they are drastically reduced delaying pilot injection; as expected, hydrogen addition promotes NOx formation, but the increase, evident with conventional pilot injection timings, becomes marginal with late injection strategy. Therefore, combustion strategy performance with late pilot injection in dual-fuel diesel/natural gas combustion conditions can be further improved with 10% hydrogen addition to natural gas.

Experimental Studies of Biogas in a Single Cylinder Diesel Engine by Dual Fuel Mode of Operation

2019 ◽  
Vol 895 ◽  
pp. 109-114 ◽  
Author(s):  
C. Jagadish ◽  
Gumtapure Veershetty
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Experimental Studies ◽  
Experimental Result ◽  
Dual Fuel ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Single Cylinder ◽  
Full Load ◽  
Injection Water

The aim of this work is to examine the performance, combustion as well as emission characteristics of diesel engine performed for various mixtures of methane-enriched biogas (95% CH4). Experiments were performed on a single cylinder, four-stroke constant speed, direct injection, water-cooled diesel engine. The engine is operated by means of dual fuel mode using diesel and different mixtures of methane-enriched biogas (BG) like BG10, BG20, BG30, and BG40 mixed with the air (i.e. BG40-40% of CH4 by volume respectively) for different loads and at injection timing of 27.5° before top dead centre (bTDC). The performance, combustion and emission characteristics of the engine operated by dual fuel mode were experimentally analyzed, and compared with respect to diesel mode. The experimental result reveals that better performance and lower emissions were observed for BG40 compared to other mixtures. The brake thermal efficiency of BG40 is lower by 2.43% compared to diesel at full load. The cylinder peak pressure for dual fuel mode is higher by 6.55% when compared with diesel mode. NOx emission reduced by 2.6 % and CO emission increased by 3.3% compared to diesel at full load respectively. Keywords: Biogas, Energy, Combustion, Emission, Injection timing, dual fuel mode

Dual-Fueling of a Prechamber Diesel Engine With Natural Gas

1985 ◽  
Vol 107 (4) ◽  
pp. 914-921 ◽  
Author(s):  
S. Song ◽  
P. G. Hill
Keyword(s):  
Energy Consumption ◽  
Diesel Engine ◽  
Natural Gas ◽  
Consumption Rate ◽  
Dual Fuel ◽  
Combustion Mechanism ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Energy Consumption Rate ◽  
Diesel Operation

The feasibility of dual-fuel operation with natural gas in a prechamber diesel engine was studied with special emphasis on fuel consumption and cylinder pressure development. The effects of air restriction, pilot diesel flow rate, and injection timing were also investigated. Near full load the fuel energy consumption rate was close to that of straight diesel operation though at part load (in the absence of air restriction) the fuel energy consumption rate was relatively high. In the absence of injection timing adjustment the maximum power output of dual-fuel operation was severely limited by the maximum cylinder pressure. Retarding the injection timing is effective in reducing the maximum cylinder pressure to a safe level. The analysis of apparent energy release indicates the differences in combustion mechanism between auto-ignition of diesel fuel in straight diesel operation and propagation of flame fronts in dual-fuel operation.

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