MODELING CHARGE PREPARATION AND COMBUSTION IN DIESEL FUEL, ETHANOL, AND DUAL-FUEL PCCI ENGINES

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.

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

10.1115/icef2021-66341 ◽

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.

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An Experimental Study on the Performance and Emission of the diesel/CNG Dual-Fuel Combustion Mode in a Stationary CI Engine

Energies ◽

10.3390/en12203857 ◽

2019 ◽

Vol 12 (20) ◽

pp. 3857 ◽

Cited By ~ 7

Author(s):

Arkadiusz Jamrozik ◽

Wojciech Tutak ◽

Karol Grab-Rogaliński

Keyword(s):

Diesel Fuel ◽

Carbon Dioxide Emissions ◽

Combustion Engine ◽

Combustion Process ◽

Pressure Rise ◽

Dual Fuel ◽

Maximum Pressure ◽

Stable Operation ◽

Performance And Emission ◽

Ci Engine

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

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4045344 ◽

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.

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Development of a Phenomenological Combustion Simulation for a Dual Fuel Engine

Volume 2: Large-Bore Engines, Fuel Effects, Homogeneous Charge Compression Ignition, Engine Performance and Simulation ◽

10.1115/2001-ice-413 ◽

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.

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Comparative Analysis of Combustion Stability of Diesel/Ethanol Utilization by Blend and Dual Fuel

Processes ◽

10.3390/pr7120946 ◽

2019 ◽

Vol 7 (12) ◽

pp. 946 ◽

Cited By ~ 3

Author(s):

Wojciech Tutak ◽

Arkadiusz Jamrozik

Keyword(s):

Diesel Fuel ◽

Fuel Injection ◽

Combustion Process ◽

Combustion Stability ◽

Dual Fuel ◽

Maximum Pressure ◽

Compression Ignition Engine ◽

Energy Fraction ◽

Pure Ethanol ◽

Advantages And Disadvantages

The aim of the work is a comparison of two combustion systems of fuels with different reactivity. The first is combustion of the fuel mixture and the second is combustion in a dual-fuel engine. Diesel fuel was burned with pure ethanol. Both methods of co-firing fuels have both advantages and disadvantages. Attention was paid to the combustion stability aspect determined by COVIMEP as well as the probability density function of IMEP. It was analyzed also the spread of the maximum pressure value, the angle of the position of maximum pressure. The influence of ethanol on ignition delay time spread and end of combustion process was evaluated. The experimental investigation was conducted on 1-cylinder air cooled compression ignition engine. The test engine operated with constant rpm equal to 1500 rpm and constant angle of start of diesel fuel injection. The engine was operated with ethanol up to 50% of its energy fraction.

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CFD Analysis of Diesel-Methane Dual Fuel Low Temperature Combustion at Low Load and High Methane Substitution

Volume 1: Large Bore Engines; Fuels; Advanced Combustion ◽

10.1115/icef2018-9649 ◽

2018 ◽

Cited By ~ 2

Author(s):

Andrea Aniello ◽

Lorenzo Bartolucci ◽

Stefano Cordiner ◽

Vincenzo Mulone ◽

Sundar R. Krishnan ◽

...

Keyword(s):

Low Temperature ◽

Heat Release ◽

Diesel Fuel ◽

Single Stage ◽

Dual Fuel ◽

Low Temperature Combustion ◽

Two Stage ◽

Low Load ◽

Temperature Heat ◽

Temperature Combustion

Over the last few decades, emissions regulations for internal combustion engines have become increasingly restrictive, pushing researchers around the world to exploit innovative propulsion solutions. Among them, the dual fuel low temperature combustion (LTC) strategy has proven capable of reducing fuel consumption and while meeting emissions regulations for oxides of nitrogen (NOx) and particulate matter (PM) without problematic aftertreatment systems. However, further investigations are still needed to reduce engine-out hydrocarbon (HC) and carbon monoxide (CO) emissions as well as to extend the operational range and to further improve the performance and efficiency of dual-fuel engines. In this scenario, the present study focuses on numerical simulation of fumigated methane-diesel dual fuel LTC in a single-cylinder research engine (SCRE) operating at low load and high methane percent energy substitution (PES). Results are validated against experimental cylinder pressure and apparent heat release rate (AHRR) data. A 3D full-cylinder RANS simulation is used to thoroughly understand the influence of the start of injection (SOI) of diesel fuel on the overall combustion behavior, clarifying the causes of AHRR transition from two-stage AHRR at late SOIs to single-stage AHRR at early SOIs, low temperature heat release (LTHR) behavior, as well as high HC production. The numerical campaign shows that it is crucial to reliably represent the interaction between the diesel spray and the in-cylinder charge to match both local and overall methane energy fraction, which in turn, ensures a proper representation of the whole combustion. To that aim, even a slight deviation (∼3%) of the trapped mass or of the thermodynamic conditions would compromise the numerical accuracy, highlighting the importance of properly capturing all the phenomena occurring during the engine cycle. The comparison between numerical and experimental AHRR curves shows the capability of the numerical framework proposed to correctly represent the dual-fuel combustion process, including low temperature heat release (LTHR) and the transition from two-stage to single stage AHRR with advancing SOI. The numerical simulations allow for quantitative evaluation of the residence time of vapor-phase diesel fuel inside the combustion chamber and at the same time tracking the evolution of local diesel mass fraction during ignition delay — showing their influence on the LTHR phenomena. Oxidation regions of diesel and ignition points of methane are also displayed for each case, clarifying the reasons for the observed differences in combustion evolution at different SOIs.

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A Analisis Kinerja PLTD Dual-Fuel Di PT. Indonesia Power UBP Bali

Jurnal METTEK ◽

10.24843/mettek.2019.v05.i01.p06 ◽

2019 ◽

Vol 5 (1) ◽

pp. 45

Author(s):

I Gede Kusuma Putra ◽

I Gusti Bagus Wijaya Kusuma ◽

I Made Dwi Budiana Penindra

Keyword(s):

Power Plant ◽

Fuel Consumption ◽

Diesel Fuel ◽

Gas Flow ◽

Dual Fuel ◽

Producer Gas ◽

Fuel System ◽

Gas Flow Rate ◽

Air Valve ◽

Electrical Loads

Penelitian kinerja PLTD dual-fuel berbahan bakar solar dan gas hasil gasifikasi bambu di PT. Indonesia Power UBP Bali ini bertujuan untuk mengetahui kemampuan bambu agar mampu mengurangi penggunaan bahan bakar solar yang kini ketersediaannya semakin menispis dengan menggunakan sistem dual-fuel pada pembangkit listrik tenaga diesel. Pengukuran dilakukan dengan mengukur laju alir udara pembakaran dengan bukaan 0%, 50% dan 100%, laju alir gas produser (syngas), konsumsi bahan bakar spesifik, dan daya genset, serta rasio beban listrik yang diberikan 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% dengan kapasitas genset 40 kW. Data yang didapatkan menunjukkan daya yang dihasilkan dari mode dual-fuel lebih besar yaitu 36,6 kW, dan konsumsi bahan bakar yang lebih sedikit yaitu 6,55 L/jam dengan 100% bukaan valve udara pembakaran.Substitusi penggunaan bahan bakar syngas terhadap bahan bakar solar mampu mengurangi total penggunaan bahan bakar solar sebesar 47,3%. Research on the performance of dual-fuel diesel power plant with diesel fuel and bamboo gasification gas in PT. Indonesia Power UBP Bali aims to determine the ability of bamboo to be able to reduce the use of diesel fuel which is now the availability is running low, by using a dual-fuel system in a diesel power plant. Measurements were made by measuring the combustion air flow with openings of 0%, 50% and 100%, producer gas flow rate (syngas), specific fuel consumption, and generator power, and the ratio of electrical loads given 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, with a generator capacity of 40 kW. The data obtained shows that the power produced from the dual-fuel mode is greater at 36.6 kW, and less fuel consumption of 6.55 L/h with 100% combustion air valve openings.The substitution for the use of syngas fuel for diesel fuel is able to reduce the total use of diesel fuel by 47.3%.

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