Experimental Investigation of Effects of Split Diesel-Pilot Injection on Emissions From Ammonia-Diesel Dual Fuel Engine

2021 ◽  
Author(s):  
Yoichi Niki
Keyword(s):  
Diesel Fuel ◽  
Internal Combustion Engines ◽  
Ghg Emissions ◽  
High Reactivity ◽  
Dual Fuel ◽  
N2o Emissions ◽  
Injection Timing ◽  
Pilot Injection ◽  
Reduce Emissions ◽  
And Performance

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.

A phenomenological combustion analysis of a dual-fuel natural-gas diesel engine

2016 ◽  
Vol 231 (1) ◽  
pp. 66-83 ◽  
Author(s):  
Shuonan Xu ◽  
David Anderson ◽  
Mark Hoffman ◽  
Robert Prucka ◽  
Zoran Filipi
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Heat Release ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Dual Fuel ◽  
Injection Timing ◽  
Heavy Duty ◽  
Engine System ◽  
Wiebe Function

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.

scholarly journals Assessment of late pilot injection effect in dual-fuel combustion

2020 ◽  
Vol 197 ◽  
pp. 06010
Author(s):  
Antonio Caricato ◽  
Antonio Paolo Carlucci ◽  
Antonio Ficarella ◽  
Luciano Strafella
Keyword(s):  
Injection Pressure ◽  
Dual Fuel ◽  
Injection Timing ◽  
Pilot Injection ◽  
Compression Ignition Engine ◽  
Engine Load ◽  
Pilot Fuel ◽  
Dual Fuel Combustion ◽  
Cylinder Compression ◽  
Injection Effect

In this paper, the effect of late injection on combustion and emission levels has been investigated on a single cylinder compression ignition engine operated in dual-fuel mode injecting methane along the intake duct and igniting it through a pilot fuel injected directly into the combustion chamber. During the tests, the amount of pilot fuel injected per cycle has been kept constant, while the amount of methane has been varied on three levels. Therefore, three levels of engine load have been tested, while speed has been kept constant equal to 1500rpm. Pilot injection pressure has been varied on three set points, namely 500, 1000 and 1500 bar. For each engine load and injection pressure, pilot injection timing has been swept on a very broad range of values, spanning from very advanced to very late values. The analysis of heat release rate indicates that MK-like conditions are established in dual-fuel mode with late pilot injection. In these conditions, pollutant species, and NOx levels in particular, are significantly reduced without penalization – and in several conditions with improvement – on fuel conversion efficiency.

Spray and Combustion Characteristics of Biodiesel∕Diesel Blended Fuel in a Direct Injection Common-Rail Diesel Engine

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Hyun Kyu Suh ◽  
Hyun Gu Roh ◽  
Chang Sik Lee
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Direct Injection ◽  
Injection Rate ◽  
Combustion Characteristics ◽  
Biodiesel Fuel ◽  
Injection Timing ◽  
Pilot Injection ◽  
Blended Fuel ◽  
Conventional Diesel Fuel

The aim of this work is to investigate the effect of the blending ratio and pilot injection on the spray and combustion characteristics of biodiesel fuel and compare these factors with those of diesel fuel in a direct injection common-rail diesel engine. In order to study the factors influencing the spray and combustion characteristics of biodiesel fuel, experiments involving exhaust emissions and engine performance were conducted at various biodiesel blending ratios and injection conditions for engine operating conditions. The macroscopic and microscopic spray characteristics of biodiesel fuel, such as injection rate, split injection effect, spray tip penetration, droplet diameter, and axial velocity distribution, were compared with the results from conventional diesel fuel. For biodiesel blended fuel, it was revealed that a higher injection pressure is needed to achieve the same injection rate at a higher blending ratio. The spray tip penetration of biodiesel fuel was similar to that of diesel. The atomization characteristics of biodiesel show that it has higher Sauter mean diameter and lower spray velocity than conventional diesel fuel due to high viscosity and surface tension. The peak combustion pressures of diesel and blending fuel increased with advanced injection timing and the combustion pressure of biodiesel fuel is higher than that of diesel fuel. As the pilot injection timing is retarded to 15deg of BTDC that is closed by the top dead center, the dissimilarities of diesel and blending fuels combustion pressure are reduced. It was found that the pilot injection enhanced the deteriorated spray and combustion characteristics of biodiesel fuel caused by different physical properties of the fuel.

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
Keyword(s):  
Diesel Fuel ◽  
Combustion Process ◽  
Operating Conditions ◽  
Critical Parameters ◽  
Dual Fuel ◽  
Injection Timing ◽  
Analytical Methodology ◽  
Cycle Variation ◽  
Medium Speed ◽  
Substitution Ratio

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.

Development of a Phenomenological Combustion Simulation for a Dual Fuel Engine

2001 ◽  
Author(s):  
Yafeng Liu ◽  
Stuart R. Bell ◽  
K. Clark Midkiff
Keyword(s):  
Natural Gas ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Air Entrainment ◽  
Dual Fuel ◽  
Nox Emissions ◽  
Cycle Simulation ◽  
Specific Performance ◽  
Combustion Simulation ◽  
Reduce Emissions

Abstract A phenomenological cycle simulation for a dual fuel engine has been developed to mathematically simulate the significant processes of the engine cycle, to predict specific performance parameters for the engine, and to investigate approaches to improve performance and reduce emissions. The simulation employs two zones (crevice and unburned) during the processes of exhaust, intake, compression before fuel injection starts, and expansion after combustion ends. From the start of fuel injection to the end of combustion, several, zones are utilized to account for crevice flow, diesel fuel spray, air entrainment, diesel fuel droplet evaporation, ignition delay, flame propagation, and combustion quenching. The crevice zone absorbs charge gas from the cylinder as pressure increases, and releases mass back into the chamber as pressure decreases. Some crevice mass released during late combustion may not be oxidized, resulting in emissions of hydrocarbon and carbon monoxide. Quenching ahead of the flame front may leave additional charge unburned, yielding high methane emissions. Potential reduction of engine-out NOx emissions with natural gas fueling has also been investigated. The higher substitution of natural gas in the engine produces less engine-out NOx emissions. This paper presents the development of the model, baseline predictions, and comparisons to experimental measurements performed in a single-cylinder Caterpillar 3400 series engine.

Diesel Fuel Multiple Injection Effects on Emission Characteristics of Diesel Engine Mixed Ammonia Gas Into Intake Air

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Yoichi Niki ◽  
Yoshifuru Nitta ◽  
Hidenori Sekiguchi ◽  
Koichi Hirata
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Internal Combustion Engines ◽  
Experimental Results ◽  
Exhaust Emission ◽  
N2o Emissions ◽  
Emission Characteristics ◽  
Exhaust Gas ◽  
N2o Production ◽  
Combustion Processes

This study focuses NH3 as an alternative fuel for internal combustion engines, because NH3 is known as a H2 carrier and its combustion does not produce CO2 causing global warming. On the other hand, some reports show that unburned NH3 and N2O appear in exhaust gas, when NH3 is used as fuel for compression ignition or spark ignition engines. NH3 is toxic and N2O is one of the greenhouse gases. These emissions should not be emitted. These reports point out that exhaust gas after treatments and/or injection strategies can be effective to reduce these emissions. From our previous investigations, it was confirmed that NH3 and N2O were contained in the exhaust gas of a conventional diesel engine with NH3 gas mixed into the engine intake. In this study, NH3 combustion processes in the diesel engine were investigated from the experimental results. Based on the investigations, a pilot or postinjection was conducted to reduce emissions of NH3 and N2O. In this paper, first the experimental results of the combustion and exhaust emission characteristics on the conventional diesel engine with NH3 gas mixed into the engine intake are shown. NH3 and N2O emissions are then verified by analyzing the exhaust gas. Next, NH3 combustion processes in the diesel engine are considered from the experimental results to report on the effects of a pilot and postdiesel fuel injection on NH3 and N2O production processes. The experimental results suggest that the multiple diesel fuel injections would be one of the effective measures to reduce N2O and NH3 emissions on NH3 and diesel dual-fueled engine.

scholarly journals A Numerical Study on the Pilot Injection Conditions of a Marine 2-Stroke Lean-Burn Dual Fuel Engine

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1396
Author(s):  
Hao Guo ◽  
Song Zhou ◽  
Jiaxuan Zou ◽  
Majed Shreka
Keyword(s):  
Natural Gas ◽  
Fuel Injection ◽  
Numerical Study ◽  
Pollutant Emissions ◽  
Dual Fuel ◽  
Injection Timing ◽  
Pilot Injection ◽  
Lean Burn ◽  
Injection Duration ◽  
Pilot Fuel

The global demand for clean fuels is increasing in order to meet the requirements of the International Maritime Organization (IMO) of 0.5% global Sulphur cap and Tier III emission limits. Natural gas has begun to be popularized on liquefied natural gas (LNG) ships because of its low cost and environment friendly. In large-bore marine engines, ignition with pilot fuel in the prechamber is a good way to reduce combustion variability and extend the lean-burn limit. However, the occurrence of knock limits the increase in power. Therefore, this paper investigates the effect of pilot fuel injection conditions on performance and knocking of a marine 2-stroke low-pressure dual-fuel (LP-DF) engine. The engine simulations were performed under different pilot fuel parameters. The results showed that the average in-cylinder temperature, the average in-cylinder pressure, and the NOx emissions gradually decreased with the delay of the pilot injection timing. Furthermore, the combustion situation gradually deteriorated as the pilot injection duration increased. A shorter pilot injection duration was beneficial to reduce NOx pollutant emissions. Moreover, the number of pilot injector orifices affected the ignition of pilot fuel and the flame propagation speed inside the combustion chamber.

An Experimental Investigation of the Effects of Common-Rail Injection System Parameters on Emissions and Performance in a High-Speed Direct-Injection Diesel Engine

1999 ◽  
Vol 123 (1) ◽  
pp. 167-174 ◽  
Author(s):  
P. J. Tennison ◽  
R. Reitz
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Direct Injection ◽  
Injection Pressure ◽  
Injection System ◽  
Injection Timing ◽  
Pilot Injection ◽  
Common Rail Injection System ◽  
And Performance ◽  
Emissions And Performance

An investigation of the effect of injection parameters on emissions and performance in an automotive diesel engine was conducted. A high-pressure common-rail injection system was used with a dual-guided valve covered orifice nozzle tip. The engine was a four-valve single cylinder high-speed direct-injection diesel engine with a displacement of approximately 12 liter and simulated turbocharging. The engine experiments were conducted at full load and 1004 and 1757 rev/min, and the effects of injection pressure, multiple injections (single vs pilot with main), and pilot injection timing on emissions and performance were studied. Increasing the injection pressure from 600 to 800 bar reduced the smoke emissions by over 50 percent at retarded injection timings with no penalty in oxides of nitrogen NOx or brake specific fuel consumption (BSFC). Pilot injection cases exhibited slightly higher smoke levels than single injection cases but had similar NOx levels, while the single injection cases exhibited slightly better BSFC. The start-of-injection (SOI) of the pilot was varied while holding the main SOI constant and the effect on emissions was found to be small compared to changes resulting from varying the main injection timing. Interestingly, the point of autoignition of the pilot was found to occur at a nearly constant crank angle regardless of pilot injection timing (for early injection timings) indicating that the ignition delay of the pilot is a chemical delay and not a physical (mixing) one. As the pilot timing was advanced the mixture became overmixed, and an increase of over 50 percent in the unburned hydrocarbon emissions was observed at the most advanced pilot injection timing.

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