Dual Fuel Research Articles

Experimental analysis on the influence of compression ratio, flow rate, injection pressure, and injection timing on the acetylene - diesel aspirated dual fuel engine.

The predicted scarcity, increasing cost of petroleum fuels, and environmental degradation are encouraging researchers to search for alternative fuels throughout the world. Hence, it is intended to utilize acetylene-based DF in the compression ignition (CI) engine with minor modifications. An engine of 5 Hp, four stroke, single-cylinder, water-cooled operated in dual-fuel (DF) mode (acetylene gas-diesel), aiming to reduce the emissions, was deployed to investigate its characteristics. In DF mode, gaseous fuel is injected through intake air manifold with 2, 4, and 6 lpm constantly. According to the research findings, the gas rate of 6 lpm provides the best results, having a superior BTE of 30.7%. Various compression ratios (16:1, 18:1, and 20:1) were used to determine the optimal compression ratio (CR) under a volume flow rate of 6 lpm with diesel. Fuel injector pressure (200, 220, and 240bar) with injector intervals (19°, 23°, and 27°bTDC) were changed consecutive sequence while adjusting CR, and the best outcomes for improved CI fuel efficiency were determined. From the investigational analysis, the peak in-cylinder pressure and net HRR (heat release rate) are assessed for being better by the increment in CR in DF mode of operation with an acetylene gas of 6 lpm at all operating settings. At a 240bar injection pressure, the BTE is recorded highest (35.1%), and smoke was decreased. An IT of 23obTDC, the CO and HC were found as to be minimum as 28ppm and 0.04ppm.

Development Procedure for Performance Estimation and Main Dimensions Calculation of a Highly-Boosted Ethanol Engine with Water Injection

The management of the global energy resources has stimulated the emergence of various agreements in favor of the environment. Among the most famous are the Conference of Parties (COP) and Route 2030, which aim to limit global warming to 1.5 °C by reducing the energy consumption and global emission levels. In order to comply with the international standards for energy consumption and pollutant emissions, the Brazilian government has been promoting the expansion of biofuels in the national energy matrix. Considering this scenario, the development of a novel internal combustion engine for the exclusive use of ethanol as a fuel, equipped with state-of-the-art technologies and employing modern design concepts, consists of an innovative and promising pathway for future Brazilian mobility, from both environmental and technological outlooks. In this sense, this work presents a method to determine the main engine dimensions as part of the initial process for a new ethanol prototype engine development. The Brazilian biofuel was selected due to its physicochemical properties, which allow the engine to achieve higher loads, and also due to its large availability as a renewable energy source in the country. Furthermore, a port water injection system was fitted to the engine in order to assist the combustion process by mitigating the knock tendency. The predicted overall engine performance was obtained by carrying out a GT-PowerTM 1D-CFD simulation, whose results pointed to a maximum torque of 279 Nm from 2000 to 4000 rpm and an indicated peak power of 135 kW at 5500 rpm. With a maximum water-to-fuel ratio of 19.2%, the engine was able to perform its entire full load curve at the MBT condition, a fact that makes the WI approach along with the ethanol fuel a very attractive solution. As a result of the specific design and optimization of each geometric parameter for this unique ethanol engine, a maximum indicated fuel conversion efficiency of 45.3% was achieved. Moreover, the engine was capable of achieving over 40% of the indicated fuel conversion efficiency in almost its entire full load curve.

Experimental Assessment of the Impact of Replacing Diesel Fuel with CNG on the Concentration of Harmful Substances in Exhaust Gases in a Dual Fuel Diesel Engine

The problem of global warming and related climate change, as well as rising oil prices, is driving the implementation of ideas that not only reduce the consumption of liquid fuels, but also reduce greenhouse gas emissions. One of them is the use of natural gas as an energy source. It is a hydrocarbon fuel with properties allowing the reduction of CO2 emissions during its combustion. Therefore, solutions are being implemented that allow natural gas to be supplied to means of transport, which are trucks of various categories and purposes. This article presents the results of tests of an engine from a used semi-truck, to which an innovative compressed natural gas (CNG) supply system was installed. This installation (both hardware and software), depending on the engine operating conditions, enables mass replacement by natural gas (up to 90%) of the basic fuel—diesel oil. During the tests, on the basis of the obtained results, the influence of the diesel fuel/CNG exchange ratio under various engine operating conditions on the concentration of toxic CO2, CO, NO, NO2, CH4, C2H6, NMHC, NH3 and exhaust smoke was assessed. The test results confirm that, compared to conventional fueling, the diesel/CNG-fueled engine allows for a significant reduction in CO2 concentration even in a car operated for several years with diesel fuel and with high mileage. The use of a non-factory installation significantly increased the concentration of methane CH4, nitrogen dioxide NO2 and carbon monoxide CO in the exhaust gas. It was found that the smoke content and the temperature of exhaust gases did not decrease with increasing ratio of fuel replacement. The concentration of CO, NOX, CH4 and NMHC was increased, while the concentration of CO2, C2H6, NH3 and the consumption of diesel fuel by the engine, decreased significantly. The innovation of the research is based on the use of a modern and unique engine gas fuel system control system where the original fuel supply system with unit pumps is able to reduce diesel oil consumption by up to 90%.

HCCI combustion of methanol along with diesel through novel injection strategies and its potential over conventional dual fuel combustion

In this experimental work Homogenous Charge Compression Ignition of methanol along with direct injection of diesel (HCCI-DI) was achieved by adapting novel injection strategies for controlling the charge homogeneity and ensuring proper combustion in a single cylinder common rail water cooled research engine run at a constant speed of 1500 rpm. Methanol was port injected while the diesel was injected as two pulses – an early first pulse (during start of suction) for enhancing the charge homogeneity and a late second pulse for controlling ignition. The effects of methanol energy share (MES), start of injection of the first and second pulses (SOI-F and SOI-S) and first pulse injected quantity (FIQ) at different loads were studied. The SOI-S of diesel had to be advanced with load for best thermal efficiency. At full load, it had to be retarded to limit knocking. Heat release analysis indicated that higher FIQs resulted in slow combustion as the charge was more homogeneous while lower FIQs formed a stratified mixture that enhanced the thermal efficiency, reduced THC and unregulated emissions while elevating the NOx levels. The thermal efficiencies were higher by about 2.9 and 1.9% compared to the Conventional Dual Fuel (CDF) operation at 75% and 50% loads. The MES that could be tolerated was higher than the CDF mode. Soot was significantly reduced as compared to the CDF mode by 94%, 87.6%, 80.3% while the NOx was reduced by 77.5%, 65.2% and 29.9% at the IMEPs of 5.1, 6.2 and 7.5 bar respectively. However, emissions of unburnt hydrocarbons, carbon mono-oxide, methanol and formaldehydes were higher than the CDF mode. On the whole the methanol diesel HCCI-DI mode has the potential for operation with higher efficiency, lower NOx and soot emissions than the CDF mode.

Investigation on the effects of blending hydrogen-rich gas in the spark-ignition engine

In order to improve the energy efficiency of the internal combustion engine and replace fossil fuel with alternative fuels, a concept of the methanol-syngas engine was proposed and the prototype was developed. Gasoline and dissociated methanol gas (GDM) were used as dual fuels and the engine performance was investigated by simulation and experiments. Dissociated methanol gas is produced by recycling the exhaust heat. The performance and combustion process was studied and compared with the gasoline engine counterpart. There is 1.9% energy efficiency improvement and 5.5% fuel consumption reduction under 2000r/min, 100 N ⋅ m working condition with methanol substitution ratio of 10%. In addition, the engine efficiency further improves with an increase of dissociated methanol gas substitution ratio because of the increased heating value of the fuel and effects of hydrogen. The peak pressure in the cylinder and the peak heat release rate of the GDM engine are higher than that of the original gasoline engine, with a phase closer to the top dead center (TDC). Therefore, blending hydrogen-rich gas in the spark-ignition engine can recycle the exhaust heat and improve the thermal efficiency of the engine.

EXAMINING THE IMPACT OF FUTURE ALTERNATIVE FUELS ON NAVAL VESSELS

Emissions regulation aimed at reducing air pollution, particularly carbon dioxide emissions, is driving commercial research into alternative fuels such as ammonia, methanol and hydrogen. Whilst naval ships, being government owned vessels, are exempt from this regulation, the ability to operate on such fuels may become a requirement for future combatants. This paper describes an ongoing study to examine the impact of alternative fuels over a range of naval vessel designs and sizes, using the ZEOLIT early-stage ship tool. The initial stage has examined an OPV, as this is a relatively simple type of vessel, which has already seen the adoption of dual fuelling with LNG in some navies. Three future fuels have been investigated: methanol, ammonia and a Liquid Organic Hydrogen Carrier. The findings so far indicate that, for an OPV, these fuels lead to an increase in displacement, but not one that would render the ship impractically large.

Electrooxidation reactions of methanol and ethanol on Pt–MoO3 for dual fuel cell applications

Pt–MoO3 was synthesized by microwave-assisted chemical reduction. The physicochemical characterization showed that the electrocatalyst contained nanoparticles of Pt and clusters of MoO3. The average particle size of the catalytic material was 2.5 nm. The electrochemical results showed that the Pt–MoO3/C was suitable to carry out the electrooxidation reactions of ethanol and methanol indistinctly, avoiding CO poisoning. It was possible to compare the results with commercial Pt/C. The synthesized material showed a better electrochemical performance. Different simulations were performed using the Nernst equation to evaluate the influence of temperature, internal resistance, and the current density losses as a function of the fuel used. The theoretical results indicated that the electrical power of the mono-cell improves by 21.5% when the energy vector is changed from methanol to ethanol at the maximum power point, obtaining an electrical potential change ΔE = 87.02 mV and a variation of the electric power of Δp = 114.14 mW cm−2. The use of dual fuels could improve the performance of experimental fuel cells.

Experimental Study on the Effect of Injection Timing on a Dual Fuel Diesel Engine Operated With Biogas Derived From Food Waste

Abstract The present work emphasizes the effects of injection timing on the characteristics of a 5.2-kW powered four-stroke diesel engine using biogas and its heat loss analysis. The biogas is obtained from food waste consisting of methane (CH4)—88.1% and carbon dioxide (CO2)—11.8% as the composition. The biogas (BG) is selected by mass basis ranging from 20% to 60% with 10% increments and is used to operate the engine by dual-fuel mode. The effect of three injection timings such as 25.5 deg (retarded), 27.5 deg (actual), and 29.5 deg (advanced) before top-dead center (bTDC) under dual-mode operation to enhance the properties of the engine is studied, and the results are compared with diesel mode at actual injection timing. Maximum brake thermal efficiency of 30.1% was observed for BG20 operated at 29.5-deg bTDC injection timing (IT). The dual mode operated at the injection timing of 29.5-deg bTDC showed an increase in cylinder pressure compared to diesel by 11.9% at full load conditions, whereas carbon monoxide emission was lower by 5.2% at 29.5-deg bTDC IT than diesel, and nitrogen oxide emission was lower at 25.5 deg bTDC IT than diesel mode by 45%. Besides, at 75% engine load, the least amount of heat losses was observed for BG50 exhibiting effective conversion of fuel energy into equivalent work higher than that of diesel by 2.2%, respectively.

Computational investigation of a venturi-type mixer for gaseous fuel application in a dual-fuel engine

The combined application of biogas (BG) and producer gas (PG) in diesel engines is a challenge and has scarcely been addressed so far. The present contribution focused on designing a venturi-type mixer to regulate the flow of these gases in a diesel engine under the dual-fuel (DF) mode. The mixer is simulated using CFD software (ANSYS 15.0) with five combinations of BG-PG flow, viz. 80-20%, 60-40%, 50-50%, 40-60% and 20-80% to analyse the flow behaviour, distribution and mixing quality of these gases with the air. The results indicated significant pressure drops at the throat section, which increases the velocity and turbulence inside the mixer to achieve a homogeneous mixture of gases in the divergent section. Moreover, the study resulted in lean air–fuel mixture for all flow combinations in 1.23–1.51. The proposed mixer seem to be suitable for DF engine operation with the combined application of BG and PG.

The viability of retro-fitting a re-liquefaction plant onboard a 150,000m3 DFDE LNG carrier

Changes in the type of LNG trading has resulted in an increased demand for vessels with greater operational flexibility and efficient propulsion plants. This has led to the demand for the capability to re-liquefy boil-off-gas (BOG) and return it the cargo-tanks and sell it as cargo or burn BOG or fuel oils depending on the relative costs at the time. This allows energy companies to divert LNG to markets with high seasonal peak demand and take advantage of highest prices, yet still meet long-term SPA's. The research in this paper was conducted by means of qualitative data collection and subsequent analysis using market management tools to ascertain the technical viability. From this point, the data was fed into economic analysis to produce quantitative data that allowed for a determination for a final investment decision for a number of market scenarios. LNG carriers with re-liquefaction capability are positively differentiated from those without it. They are capable of greater operational flexibility, and as a result, their competitive position is improved. They can demand higher charter rates as the increase in cargo quantity offloaded results in increased revenue. They present a lower environmental footprint as there is no requirement to thermally oxidise excess BOG in a GCU. The analysis shows it is technically viable to retrofit a re-liquefaction plant onboard 150,000 m3 Dual Fuel Diesel Electric (DFDE) LNG carriers. The economic viability is more complicated, situation-dependent, and influenced by market forces, environmental legislation, and political interference.

Experimental Probe Into a Biogas Run Dual Fuel Diesel Engine Using Oxygenated Ternary Blends at Optimum Equivalence Ratio and Under the Effect of Intake Charge Preheating

AbstractThe key challenge of dual fuel mode (DFM) of a compression ignition (CI) diesel engine is to improve the engine performance, and to reduce primarily the carbon monoxide (CO) and unburnt hydrocarbon (HC) emissions. The gaining popularity of DFM lies with its inherent ability to curb harmful pollutants, besides offering operational flexibility to use gaseous and liquids fuels simultaneously. In addition, the use of renewable fuels in DFM is found to be highly suitable to achieve the optimum engine overall performance. In this DFM study, biogas as the primary gaseous fuel is used in a diesel engine in conjunction with ternary blends of diesel-biodiesel-ethanol (TB-E), diesel-biodiesel-butanol (TB-BT), and diesel-biodiesel-diethyl ether (TB-DEE) as the renewable pilot fuels. For each combination, the experiments are conducted at the optimum global fuel–air equivalence ratio (Φglobal) and with intake charge preheating to analyze the performance, combustion and emission characteristics of the engine. The important parameters such as brake thermal efficiency, actual diesel replacement, coefficient of variation of indicated mean effective pressure, relative cycle efficiency, cylinder mean gas temperature, ignition delay, and combustion duration are investigated. The study demonstrates the optimum performance of the DFM engine with TB-DEE.

Effects of hydrogen enrichment and turbulence intensity on the combustion mode in locally stratified dual-fuel mixtures of n-dodecane/methane

In dual-fuel (DF) engines, a high-reactivity fuel (HRF) ignites a low-reactivity fuel (LRF) premixed with air. Identification of the combustion mode after autoignition in DF engines with different fuel combinations and under various mixture stratification levels is of crucial importance since the combustion mode may affect the engine performance and emissions levels. However, to avoid expensive computational or experimental tests for different fuel combinations under various initial conditions, an analytical diagnostics tool can help identify the modes of combustion. Recently, we developed an a-priori tool (β-curve), which separates between the deflagration and spontaneous combustion modes in transient problems based on two parameters: HRF stratification amplitude and wavelength. However, the developed analysis was only evaluated for a single fuel combination and under 2D turbulent conditions. The present study extends our previous work by (1) evaluating the 1D β-curve analysis for more common fuel combinations including hydrogen, and (2) extending the combustion mode analysis to 3D turbulent combustion. First, using 1D numerical simulations, the combustion mode for a new DF combination of n-dodecane (HRF) and methane (LRF) with and without hydrogen enrichment in the LRF blend is investigated. Although hydrogen enrichment shortens the combustion duration, its role in changing the combustion mode remains subtle. Therefore, only n-dodecane/methane (no hydrogen enrichment) is considered in the 3D simulations to avoid highly expensive 3D numerical simulations with hydrogen enrichment. Second, using flame-resolved 3D numerical simulations, variations of the combustion mode for DF n-dodecane/methane mixtures at three different turbulence intensities are studied. It is observed that high turbulence levels can switch the combustion mode from deflagration to autoignition. For the first time, the diagnostic tool is evaluated compared to 3D turbulent numerical simulations and a correction factor is proposed in the β-curve equation.

Stabilization regimes and pollutant emissions from a dual fuel CH4/H2 and dual swirl low NOx burner

Burning hydrogen in gas turbines is a relevant technological solution to decarbonize power production and propulsion systems. However, ensuring low NOx emission and preventing flashback can be challenging with hydrogen. Stabilization regimes and pollutant emissions from partially premixed CH4/H2/air flames above a coaxial Dual Fuel Dual Swirl injector are investigated in a laboratory-scale combustor at atmospheric conditions for increasing hydrogen contents. The injector consists of an external annular swirler providing premixed methane/air and a central channel fed with pure hydrogen. This burner virtually removes the risk of flashback due to the late injection of hydrogen. Flame stabilization regimes, CO and NOx emissions are analyzed for different configurations of the injector and operating points. The effect of swirling the hydrogen stream is investigated together with the influence of the hydrogen injector recess, i.e. its nozzle position with respect to the backplane of the combustion chamber. It is shown that swirling the central hydrogen stream favors aerodynamically stabilized flames resulting in a low thermal stress on the injector and limited NOx emissions. The study also highlights that a small recess of the central hydrogen injector widely extends the operability range of the burner with aerodynamically stabilized flames. With a sufficient inner swirl and a small recess, flames detach from the injector rim when the hydrogen bulk velocity is large enough. In this configuration, it is found that NOx emissions remain low even for operation with pure hydrogen. Moreover, NOx emissions decrease when increasing the thermal power for a fixed equivalence ratio.

Modeling the spray characteristics of blended fuels for gasoline direct injection applications

ABSTRACT Methanol and ethanol are considered as potential candidates for alternative fuels in spark-ignited engines and flex-fuel vehicles. Alcoholic fuels have higher latent heat of vaporization (), lower boiling-point temperature and higher-octane numbers help the engine run under higher compression ratios, resulting in better efficiency and fuel economy. A numerical study is carried out to understand the spray-breakup and vaporization characteristics of binary blended fuel and ternary fuel blend compared to single-component fuel for gasoline direct injection (GDI) system. Multiple simulations were carried out by substituting individual fuel properties of isooctane with those of ethanol to understand the relative importance and effect of fuel properties on spray characteristics. The spray characteristics of pure isooctane fuel and their blends with ethanol and methanol are studied and compared, and the charge cooling effects for alcoholic fuels have been observed. The Spray G operating condition has been taken from the Engine Combustion Network (ECN) for this study. The simulated data for isooctane has been validated with the experimental data from the ECN, and a similar model setup has been used for pure and blended fuel sprays. The discrete-phase modeling (DPM) approach is carried out, and the Unsteady Reynolds-Averaged Navier–Stokes (URANS) RNG (Renormalization) k-ε turbulence model is considered in understanding the spray characterization. The blended methanol fuels have higher penetration lengths compared with ethanol ones. The penetration of the blended fuels (binary and ternary) is slightly lower than the isooctane. The ternary blends showed spray characteristics similar to those of E85, and it indicates that the ternary blended fuel has the potential to be used as a drop-in fuel for a GDI-based flex-fuel vehicle.

A Complete Assessment of Tribo-corrosive Behaviour of CI Engine Using Emulsified Dual Fuel Bio-Diesel Blend

A Complete Assessment of Tribo-corrosive Behaviour of CI Engine Using Emulsified Dual Fuel Bio-Diesel Blend

Effect of venture design on the performance of CNG and biogas operated dual fuel engine with jamun seed oil methyl ester blends

In the present work, effect of mixing gas venture (GV) on the performance of modified dual fuel (DF) engine with effective utilization of biodiesel and gaseous fuel combinations is reported. Biodiesel prepared jamun seed oil called jamun seed oil methyl ester (JAMUNME B100) and its B20 blend (JAMUNME B20) are used as pilot injected fuels while the biogas and compressed natural gas (CNG) are used as the inducted fuels in the modified DF engine. Hence, the present research focus on the enhancing of engine performance of DF engine fuelled with liquid and gaseous fuel combinations. Meanwhile, the effect of GV on modified DF engine performance is investigated. Higher brake thermal efficiency (BTE), lower carbon monoxide (CO), hydrocarbon (HC) and smoke emissions besides higher NOx emissions are observed with higher methane content gas. Combustion parameters such as ignition delay (ID), and peak pressure (PP) are analysed. The DF engine operated on renewable fuel combinations in DF mode can cover the way for partial substitution of fossil fuel along with reduction in greenhouse gas emissions. Increasing the number of orifices in GV will improve the gas-air mixing ratio.

Precise prediction of performance and emission of a waste derived Biogas–Biodiesel powered Dual–Fuel engine using modern ensemble Boosted regression Tree: A critique to Artificial neural network

The current study looks at using waste-derived biodiesel as pilot fuel and waste-derived biogas as a gaseous fuel to power a diesel engine in dual-fuel mode. A new ensemble approach called Boosted Regression Trees (BRT) was utilized to model the performance and emissions of a variable compression ratio diesel engine. The model's input parameters were selected to be load, fuel injection time, and compression ratio. The BRT-based model was created based on experimental data to predict brake thermal efficiency (BTE), Biogas Fuel Ratio (BFR), NOx, CO, and HC. As indicated by correlation values ranging from 0.9947 to 0.9997, low Theil's values (0.081), and high Kling-Gupta efficiency (>98 percent), the suggested BRT model predicted performance and emission parameters with reasonable accuracy. The BRT model was compared to an ANN model under similar operating conditions. The BRT-based model outperformed the ANN-based model on all statistical metrics. The efficacy of BRT models was demonstrated further by employing a novelmethod of comparing prediction models using Taylor's diagram.

Design and Test of Natural Gas Diesel Dual Fuel Engine Based on SolidWorks

Taking ZS1115 diesel engine as an example, on the basis of basically not changing the original structure, natural gas inlet valve, natural gas air mixer and natural gas governor are added to realize dual fuel combustion control. The model of dual fuel engine is established by using SolidWorks software, and the size and performance parameters of main mechanical structures are optimized and simulated by using modules such as simulationmotion, simulationxpress and simulationflow. The bench test results show that the dual fuel engine designed based on SolidWorks runs stably, and the power, economy and emission performance meet the design requirements.

Experimental Investigations on Enhancement of DME Energy Shares in Compression-Ignition Engine Under Dual Fuel Mode Using Reduced Compression Ratio

The effects of the compression ratio (CR), which was reduced from base (19:1) to (17:1), on the enhancement of Dimethyl Ether Energy Share (DME ES) and emissions reduction in a 5.5 kW DICI (direct injection compression ignition) engine are studied. The experimental tests were conducted on the engine with DME as main fuel and diesel as pilot fuel at 13 Nm torque and speed of 2200 rpm condition under dual fuel mode (DME-diesel). The maximum DME energy share (DME ES) enhanced drastically from 44% with base CR to 53% with the reduced CR. Smoke emission decreased to nearly zero levels with both CRs (19:1 and 17:1). CO and HC emissions significantly decreased with 53% of DME ES with reduced CR. NOx emission decreased drastically with the reduced CR (17:1). However, brake thermal efficiency is marginally droped with the reduced compression ratio. The combustion characteristics are discussed in detail.

Modeling and Optimization of the Flue Gas Heat Recovery of a Marine Dual-Fuel Engine Based on RSM and GA

Implementation of flue gas waste heat recovery is an effective way to improve the energy utilization of marine engines. This paper aims to model and optimize a marine four-stroke dual-fuel (DF) engine coupled with a flue gas waste heat recovery system. Firstly, the DF engine and waste heat recovery system were respectively modeled in GT-Power and Simulink environments and verified with experimental data. Then, a regression model was built using the response surface method, with the intake temperature, compression ratio, and pilot fuel injection timing as input parameters and parametric analysis was performed. Finally, multi-objective optimization of the waste heat recovery system was performed using a genetic algorithm. The result showed that the optimal solution is obtained when the intake temperature is 306.18 K, the geometric compression ratio is 14.4, and the pilot fuel injection timing is −16.68 °CA after the top dead center. The corresponding brake-specific fuel consumption was 155.18 g/kWh, reduced by 3.24%, and the power was 8025.62 kW, increased by 0.32%. At the same time, 280.98 kW of flue gas waste heat generation was obtained.