Influence of Diesel Fuel Injection Characteristics on Dual-Fuel Combustion Modes in a Large-Bore, Medium-Speed Engine

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Adam Klingbeil ◽  
Seunghyuck Hong ◽  
Roy J. Primus

Abstract Experiments were conducted on a large bore, medium speed, single cylinder, diesel engine to investigate operation with substitution ratio of natural gas (NG) varying from 0% to 93% by energy. In a previous study by the same group, these data were used to validate an analytical methodology for predicting performance and emissions under a broad spectrum of energy substitution ratios. For this paper, these experimental data are further analyzed to better understand the performance and combustion behavior under NG substitution ratios of 0%, 60%, and 93%. These results show that by transitioning from diesel-only to 60% dual-fuel (DF) (60% NG substitution ratio), an improvement in the NOx-efficiency trade-off was observed that represented a ∼3% improvement in indicated efficiency at constant NOx. Further, the transition from 60% DF to 93% DF (93% NG substitution ratio) resulted in additional efficiency improvement with a simultaneous reduction in NOx emissions. The data suggest that this improvement can be attributed to the premixed nature of the high substitution ratio case. Furthermore, the results show that high cycle-to-cycle variation was observed for some 93% DF combustion tests. Further analysis, along with diesel injection rate measurements, shows that the observed extreme sensitivity of the combustion event can be attributed to critical parameters such as diesel fuel quantity and injection timing. These results suggest a better understanding of the relative importance of combustion system components and operating conditions in controlling cycle-to-cycle variation of combustion process.

Author(s):  
Adam Klingbeil ◽  
Seunghyuck Hong ◽  
Roy J. Primus

Experiments were conducted on a large bore, medium speed, single cylinder, diesel engine to investigate operation with substitution ratio of natural gas varying from 0 to 93% by energy. As reported in a previous publication [1], these data were used to validate an analytical methodology for predicting performance and emissions under a broad spectrum of energy substitution ratios. For this paper, these experimental data are further analyzed to better understand the performance and combustion behavior under natural gas substitution ratios of 0%, 60% and 93%. These results show that by transitioning from diesel to 60% dual-fuel (60% NG substitution ratio), an improvement in the NOx-efficiency trade-off was observed that represented a ∼3% improvement in efficiency at constant NOx. Further, the transition from 60% dual-fuel to 93% dual-fuel (93% NG substitution ratio) resulted in additional efficiency improvement with a simultaneous reduction in NOx emissions. The data suggest that this improvement can be attributed to the premixed nature of the high substitution ratio. Furthermore, the results show that high cycle-to-cycle variation was observed for the 93% dual-fuel combustion tests. Further analysis, along with diesel injection rate measurements, show that the observed extreme sensitivity of the combustion event can be attributed to critical parameters such as diesel fuel quantity and injection timing. Results suggest a better understanding of the relative importance of combustion system components and operating conditions in controlling cycle-to-cycle variation of combustion process.


2014 ◽  
Vol 525 ◽  
pp. 227-231 ◽  
Author(s):  
Min Xiao ◽  
Chun Long Feng

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.


2017 ◽  
Vol 168 (1) ◽  
pp. 73-76
Author(s):  
Marcin WOJS ◽  
Piotr ORLIŃSKI ◽  
Jakub LASOCKI

The present study describes selected issues associated with the emission level in toxic exhaust gases and fuel injection timing. The study was focused on the following types of fuels: Diesel oil (the base fuel) and the other fuels were the mixture of fatty acid methyl ester with Camelina (L10 – diesel fuel with 10% V/V FAME of Camelina and L20 – diesel fuel with 10% V/V FAME of Camelina) was used. Fuel injection advanced angle was set for three different values – the factory setting – 12° before TDC, later injection – 7° and earlier injection – 17°. The most important conclusion is that in most measurement points registered in the same engine operating conditions, the concentration of fuel NOx in L10 and L20 increased but PM emissions decreased which is caused by active oxygen located in the internal structure of the fuel. This fact contributes to the rise in temperature during the combustion process. At the same time factory settings of the angle makes NOx emissions lower and close to reference fuel.


Transport ◽  
2018 ◽  
Vol 33 (3) ◽  
pp. 633-646 ◽  
Author(s):  
Wojciech Tutak ◽  
Arkadiusz Jamrozik ◽  
Ákos Bereczky ◽  
Kristof Lukacs

The paper presents the results of the investigation of Dual Fuel (DF) diesel engines powered by high bioethanol contain fuel – E85. The object of the investigation is a three-cylinder Compression Ignition (CI) Internal Combustion Engine (ICE) powered by diesel oil and bioethanol fuel E85 injected into the intake port as a DF engine. With the increase in the share of E85 fuel the highest intensification of the combustion process takes place in the main stage of the combustion and the ignition delay increases as well. The researchers are conducted using Computational Fluid Dynamics (CFD) method; the results of the investigation are successfully verified based on the indicator diagrams, heat performance rate and emissions. Based on CFD results the cross sections investigation of the combustion chamber it can be seen that in case of the DF engine, the flame front propagates with a higher speed. The initial phase of the combustion starts in a different location of the combustion chamber than in the classic CI engine. Replacement of diesel fuel by E85 in 20% resulted in the shortening of the combustion duration more than 2-times. With the increase of energetic share in E85 the soot emission is decreased at all ranges of the analysed operations of the engine. The oppositerelationship was observed in case of NO emission. With the increase of E85 in the fuel, the emission of NO increased.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1342
Author(s):  
Van Chien Pham ◽  
Jae-Hyuk Choi ◽  
Beom-Seok Rho ◽  
Jun-Soo Kim ◽  
Kyunam Park ◽  
...  

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.


Author(s):  
Shuonan Xu ◽  
David Anderson ◽  
Mark Hoffman ◽  
Robert Prucka ◽  
Zoran Filipi

Energy security concerns and an abundant supply of natural gas in the USA provide the impetus for engine designers to consider alternative gaseous fuels in the existing engines. The dual-fuel natural-gas diesel engine concept is attractive because of the minimal design changes, the ability to preserve a high compression ratio of the baseline diesel, and the lack of range anxiety. However, the increased complexity of a dual-fuel engine poses challenges, including the knock limit at a high load, the combustion instability at a low load, and the transient response of an engine with directly injected diesel fuel and port fuel injection of compressed natural gas upstream of the intake manifold. Predictive simulations of the complete engine system are an invaluable tool for investigations of these conditions and development of dual-fuel control strategies. This paper presents the development of a phenomenological combustion model of a heavy-duty dual-fuel engine, aided by insights from experimental data. Heat release analysis is carried out first, using the cylinder pressure data acquired with both diesel-only and dual-fuel (diesel and natural gas) combustion over a wide operating range. A diesel injection timing correlation based on the injector solenoid valve pulse widths is developed, enabling the diesel fuel start of injection to be detected without extra sensors on the fuel injection cam. The experimental heat release trends are obtained with a hybrid triple-Wiebe function for both diesel-only operation and dual-fuel operation. The ignition delay period of dual-fuel operation is examined and estimated with a predictive correlation using the concept of a pseudo-diesel equivalence ratio. A four-stage combustion mechanism is discussed, and it is shown that a triple-Wiebe function has the ability to represent all stages of dual-fuel combustion. This creates a critical building block for modeling a heavy-duty dual-fuel turbocharged engine system.


2021 ◽  
Author(s):  
Yoichi Niki

Abstract NH3 has been investigated for its use as an alternative fuel including for use in internal combustion engines. In NH3 combustion, emissions of unburned NH3 with toxicity and N2O as a combustion product with high global warming potential (GWP) are important issues. However, few researchers have investigated NH3 and N2O emissions from NH3 assisted diesel engines operated using NH3–diesel dual fuel. We investigate a combustion strategy to reduce these emissions with a single-cylinder diesel engine mixed NH3 gas into the intake air. We found that an early diesel pilot injection reduced unburned NH3 and N2O emissions while HC and CO emissions increased. It was also reported that NH3 and diesel fuel work as low and high reactivity fuel for reactivity controlled compression ignition combustion (RCCI), respectively. Our previous study reports the aspects of RCCI on NH3–diesel dual fuel engine to some extent. The injection timing of diesel fuel and the quantity of NH3 govern the emissions and performance on RCCI combustion. These effects need to be investigated to manipulate the RCCI combustion and reduce emissions. This paper reports the efficiency and emissions for the diesel pilot injection timing sweep at various NH3 supply quantities and the effects of a split injection on the emissions and a combustion phase. In addition, we estimated the reduction in GHG emissions using a NH3–diesel dual fuel engine, which applied the early diesel pilot injection, compared with the diesel only operation, considering the N2O GWP.


Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3857 ◽  
Author(s):  
Arkadiusz Jamrozik ◽  
Wojciech Tutak ◽  
Karol Grab-Rogaliński

One of the possibilities to reduce diesel fuel consumption and at the same time reduce the emission of diesel engines, is the use of alternative gaseous fuels, so far most commonly used to power spark ignition engines. The presented work concerns experimental research of a dual-fuel compression-ignition (CI) engine in which diesel fuel was co-combusted with CNG (compressed natural gas). The energy share of CNG gas was varied from 0% to 95%. The study showed that increasing the share of CNG co-combusted with diesel in the CI engine increases the ignition delay of the combustible mixture and shortens the overall duration of combustion. For CNG gas shares from 0% to 45%, due to the intensification of the combustion process, it causes an increase in the maximum pressure in the cylinder, an increase in the rate of heat release and an increase in pressure rise rate. The most stable operation, similar to a conventional engine, was characterized by a diesel co-combustion engine with 30% and 45% shares of CNG gas. Increasing the CNG share from 0% to 90% increases the nitric oxide emissions of a dual-fuel engine. Compared to diesel fuel supply, co-combustion of this fuel with 30% and 45% CNG energy shares contributes to the reduction of hydrocarbon (HC) emissions, which increases after exceeding these values. Increasing the share of CNG gas co-combusted with diesel fuel, compared to the combustion of diesel fuel, reduces carbon dioxide emissions, and almost completely reduces carbon monoxide in the exhaust gas of a dual-fuel engine.


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