Dual Fuel Diesel Engine Research Articles

The Effect of Biodiesel, Ethanol, and Water on the Performance and Emissions of a Dual-Fuel Diesel Engine with Natural Gas: Sustainable Energy Production through a Life Cycle Assessment Approach

Diesel fuel (DF) is a significant power supply in agricultural, industrial, and transportation applications. Establishing sustainable and renewable fuel substitutes for diesel has become increasingly common due to the rising expense of petroleum resources and the pollution rate crises. A biodiesel-DF mixture in a dual-fuel (DuF) diesel engine (DE) can bring favorable environmental results. In the present study, three rates of ethanol (0, 2, and 4%), two rates of biodiesel (0 and 5%), and four rates of water (0, 0.3, 0.6, and 0.9%) were blended with DF. All these samples were considered pilot fuel (PF) in the DuF combustion process with an 80% natural gas (NG) replacement percentage. The combustion process was investigated from engine emissions and performance, power cost, and life cycle assessment (LCA) to obtain a sustainable fuel formulation. As a result, water, ethanol, and the combination of water-ethanol and NG can enhance the DE’s performance by rising the inside pressure of the cylinder. The presence of oxygen content in ethanol can improve the combustion process by pushing the combustion towards complete combustion. The optimum engine performance point at full load was obtained with a fuel sample containing 1.57% biodiesel, 4.38% ethanol, 1.1% water, and 80% NG. In optimum condition, the brake power (BP) was 24.16 kW, and the brake-specific fuel consumption (BSFC) was 60.64 g/kWh. This fuel sample produces 0.46, 364.08, 1.66, and 1088.29 g/kWh of BSCO, BSCO2, BSNOx, and BSO2, respectively. At this point, the energy production cost was $0.783/kWh. The environmental impacts of the combustion process at optimal fuel formulation were 0.34249, 1.00 E + 02 , 1.53 E + 00 , and 1.94 E − 06 , respectively, for ecosystem quality (EQ) (PDF ∗ m2 ∗ yr), resources (R) (MJ primary), climate change (CCh) (kg CO2 eq), and human health (HH) (DALY). Accordingly, the best fuel combination was selected to be NG+B1.5E4.3W1.1.

Penggunaan bahan bakar terbarukan (biodiesel-hydrogen) pada mesin Diesel Dual Fuel untuk mendukung Energy Transition di Indonesia

Increasing demand for oil as a fuel and declining production in refineries led to a nationwide fuel oil shortage. Hence compelling academics to develop answers, renewable energy is one of the proposed options. Compression ignition machines utilize renewable fuels such as biodiesel, crude palm oil (CPO), and hydrogen gas. Using biodiesel without modifying the engine can result in decreased thermal efficiency and increased smoke emissions. The addition of modest volumes of hydrogen gas can enhance the performance of diesel engines. The purpose of this investigation is to investigate the performance and emissions of diesel dual-fuel engines. In this investigation, a one-cylinder diesel engine with direct injection was operated at a constant 2000rpm with a 50 percent load. Flow variations of 2.5, 5, 7.5, and 10 liters per minute of hydrogen. Compared to biodiesel fuel, the results of this study indicate that a 10LPM hydrogen flow can boost thermal efficiency by 29.85% and a 7.5LPM hydrogen flow can increase power by 0.78 %. Moreover, the use of hydrogen gas reduces exhaust pollutants. Reduced HC, CO, and CO2 emissions by 26ppm, 0.01%, and 2.60%, respectively, for a 10LPM hydrogen flow.

Co-gasification of waste triple feed-material blends using downdraft gasifier integrated with dual fuel diesel engine: An RSM-based comparative parametric optimization

Biomass has promising potential as feed material for gasification and subsequent power generation, whereas these sources are seasonal and scattered in the country. Therefore, the consistency of feed material availability and supply chain may be hard to maintain. Gasification with multiple feedstocks, such as biomass-coal-briquette blends, could be one of the practical solutions to mitigate the availability and supply chain problems. Therefore, the present study aims to experiment on an air-downdraft gasifier and use generated producer gas (PG) (, a mixture of gases such as hydrogen, carbon monoxide, carbon dioxide, and nitrogen produced by incomplete combustion of coal/biomass) for power generation through a dual-fuelled mode CI engine. The three input operating conditions for the gasification-engine experiment were GER (0.1–0.43), engine load (0–100%), and compression ratio (CR) 16–18, with output parameters such as engine brake power (BP), brake thermal efficiency (BTE), brake specific energy consumption (BSEC), gas substitution rate (GSR), engine emission (CO, CO2, HC, NOx), and sound. Further optimization using Response Surface Methodology (RSM) was used to obtain the optimal operating conditions with the goal of maximizing engine performance while minimizing emissions. Based on 48 experimental data sets, ANOVA analysis and RSM-based optimization has been conducted. RSM optimization showed the optimum operational conditions of 0.43 GER, 16 CR, and 100% engine load. The respective performance responses were BP 3.52 kW, BSEC 34.16 MJ/kWh, BTE 21.02%, sound intensity 90.21 db, CO 0.0918% vol., HC 17.41 ppm vol., CO2 2.05 %vol., and NOx 4.55 ppm. The average values obtained for R2 were 95–99% and a 0.72 coefficient of determination. Further, the developed model predicted the output response very closely with the experiment, found to be a 4.4% maximum error. Thus, gasification with triple feed material (biomass-coal-briquette) with engine integration could partially substitute diesel fuel with optimum exhaust emission and noise.

Mechanical engineering advantages of a dual fuel diesel engine powered by diesel and aqueous ammonia blends

With the assistance of Diesel-RK software, the volumetric replacement of aqueous ammonia (NH4OH) with original diesel is being investigated in a dual-fuel diesel engine. Three volumetric percentages of ammonia solution are used along with diesel according to the scenario: (40% NH4OH + 60% Diesel), (50% NH4OH + 50% diesel), and (60% NH4OH + 40% diesel). The numerical analysis is based on a multizone combustion model. In the zone-based approach, the governing equations for each zone are solved as open systems. Comparing diesel fuel with ammonia solutions, the results show that adding ammonia solutions decreases combustion pressure and heat release and increases Sauter diameter and ignition delay. Generally, the use of aqueous ammonia drops engine performance regardless of the percentage of NH4OH used. Since 40%, 50%, and 60% of NH4OH have lower heating values than diesel, BSFC is reduced by 7.15, 10.4%, and 15.38%, respectively. Since the addition of ammonia reduces combustion temperature significantly, a noticeable reduction in NOx emissions is achieved, reaching up to 61.75% in the case of 60% NH4OH. The results highlighted a remarkable reduction in soot emissions (43.4% for 40% NH4OH, 51.04% for 50% NH4OH, and 49% for 60% NH4OH) because the diesel was replaced with no carbon fuel, hence the engine produced less smoke compared to with the baseline case (pure diesel).

Experimental and numerical study of using of LPG on characteristics of dual fuel diesel engine under variable compression ratio

In this work, an experimental and numerical investigation are carried out to study the impact of adding Liquefied Petroleum Gas (LPG) on the characteristics of diesel engine. New injection control system (ICS) is designed to manage an LPG injector on intake manifold a single-cylinder diesel engine. The engine test rig is powered with traditional diesel fuel to generate the base line data for comparison. Different conditions of load (0%, 25%, 50%, 75%, and 100%) in terms of brake power with three compression ratios of 14.5, 15.5 and 16.5 at constant engine speed of 1500 rpm. LPG is tested in four rates (5 L/min, 10 L/min, 15 L/min, and 20 L/min). The numerical analysis is performed with the help of Diesel-RK simulation software. The multizone combustion model is adopted. Same operating conditions in the experimental work are followed in the numerical simulation. The obtained results revealed that brake thermal efficiency (BTE) and exhaust temperature are reduced while brake specific fuel consumption (BSFC) is increased as the rate of LPG increased. Inducting LPG with (5,10,15,20) L/min reduced carbon monoxide (CO) by 16.6%, 14.7%, 20.3%, and 18.8% respectively. The maximum reduction in hydrocarbon emission (HC) is 8% at the rate of 15 L/min compared to diesel. The volumetric efficiency and NOx emissions are decreased with the use of LPG. As the compression ratio increases, BTE increases and BSFC decreases because of increasing combustion temperature and pressure which decreases delay period, ignites fuel fast and produces more power in small time. The impact of increasing compression ratio reported significant reduction in, CO, HC while NOx are increased. The experimental findings are compared to the results of the Diesel-RK software, as well as with the results of other researchers and good harmony among them is noticed.

Dynamic response of the performance and emissions of an LPG diesel dual-fuel engine with water injection

This paper evaluated the dynamic response of the compression ignition engine's performance parameters and emissions when water was injected into the intake manifold at different water ratios. This technique effectively decreased NOx emissions and mitigated knock intensity when the engine ran at dual fuel mode. With a WR = 143 %, NOx emissions were reduced by 52 % at 100 % diesel operation, whereas with a WR = 132 %, NOx emissions were reduced by 57 % at dual fuel mode operation. The knock intensity decreased from 1.52 V to 1.12 V using a water ratio of 133 % when the engine operated with a substitution of diesel by LPG of 50 % on a mass basis. The results also revealed that water injection increased HC emissions from 220 ± 1 ppm to 430 ± 1 ppm, whereas the Particle Matter (PM2.5) increased from 42.4 μg/kWh to 127.3 μg/kWh at 100 % diesel operation. When the engine operated at dual fuel mode PM2.5 increased from 42.4 μg/kWh to 84.3 μg/kWh. Finally, two First Order plus Dead Time models were deduced through the system identification technique to simulate the dynamic response of Knock Intensity when a step change of water ratio was made. These models play a key role in tuning system controllers for knock suppression.

Performance and Combustion Process of a Dual Fuel Diesel Engine Operating with CNG-Palm Oil Biodiesel

Efforts to build and develop a low-emission transportation system have been carried out, one of which is by applying biodiesel and gas to dual-fuel diesel engines. Biodiesel is an oxygenated, low-sulfur, and high flash point alternative diesel fuel. In the dual fuel mode, CNG is used as a substitute fuel and palm biodiesel as a combustion pilot which is injected directly into the combustion chamber at 13 °CA BTDC. CNG injection timing was 110 °CA ATDC and the CNG injection duration was gradually increased. Performance and combustion processes in single-fuel mode and dual-fuel mode are compared. The engine was kept at a constant speed of 2000 rpm at all load conditions. The results show that the dual fuel mode at low and medium loads produces in-cylinder pressure and the heat release rate is lower than the single fuel mode, but at high loads, it produces in-cylinder pressure and the heat release rate is 5.14% greater. CO and HC emissions produced by the dual fuel mode are higher than the single fuel mode at all loads. conversely, the dual-fuel mode produces 95.58% lower smoke emissions than the single-fuel mode at all loads.

Investigations on a novel fuel water hyacinth biodiesel and Hydrogen-Powered engine in Dual-Fuel Model: Optimization with I-optimal design and desirability

Hydrogen is one of the most promising green fuels. The present study explores the potential of novel water hyacinth biodiesel as pilot fuel as well as investigates the influence of the injection pressure of pilot fuel on the performance of hydrogen running a dual-fuel diesel engine. For experimentation, a 4.8 kW research test engine was considered. Three fuel injection pressure (FIP) of the pilot fuel, namely 220 bar, 240 bar, and 260 bar were considered at a ratio of compression as 17.5 and standard injection timing of 23° before Top Dead Centre (bTDC) for different loading conditions were considered. The peak brake thermal efficiency (BTE) under dual fuel mode (DFM) was observed as 26.77%, 28.11%, and 27.21% for FIP of the pilot fuel of 220 bar, 240 bar, and 260 bar, respectively in comparison to 25.11% for biodiesel mode at 100% load. The maximum drop in carbon monoxide (CO) and hydrocarbon (HC) emissions was found to be 15.48%, and 35.7%, respectively for the FIP of the pilot fuel of 240 bar under DFM in comparison to biodiesel mode. The fall in Oxides of Nitrogen (NOX) emission under DFM was found to be 23.66% for the FIP of the pilot fuel of 220 bar under DFM compared to biodiesel mode. Based on the performance and emission analysis, the optimum FIP of the pilot fuel is found to be 240 bar. For the same FIP, the maximum liquid fuel replacement of 85% was obtained. The experimental study’s data were evaluated using analysis of variance (ANOVA) to create models in the form of mathematical expressions for each outcome. The desirability approach was employed to optimize the operating settings for maximum performance while emitting the least amount of emission. According to the desirability-based optimization research, ideal operating conditions were 83.61% engine load and 242 bar FIP, resulting in engine performance of 26.5% of BTE, 80.47% of LFR, and 51.82 bar peak cylinder pressure. The emission levels were 191.19 ppm of NOX, 106.41 ppm of HC, and 130.95 ppm of CO at this setting. A model validation test found that the model-predicted values were within 6% of the observed values.

Effect of vibration and pressure on the air-bioCNG mixture inside the manifolds of dual-fuel diesel engines

Abstract The vibration generated by diesel engines may influence air and gaseous fuel mixing in dual-fuel mode. This study is performed on the manifolds of single and twin-cylinder engines in diesel-bioCNG dual-fuel mode. It examines the effect of the engine vibration and variable manifold pressure on the flow behaviour of the air-bioCNG mixture. The objective is to observe the flow inside the manifolds and mixture quality at the outlet. The mentioned work has found little attention till date. The computational comparison of the flow characteristics inside the intake manifold of the single-cylinder engine is done for an F-shape manifold of the twin-cylinder engine during suction stroke. The experiments are conducted to record both the engines' vibration signature and cycle data. For this, the same operating parameters are maintained: compression ratio of 16.5, engine speed of 1500 rpm, engine load range (0 Nm to 34 Nm) and 80% bioCNG substitution. It employs the boundary conditions, such as the vibration amplitude along three axes, variable manifold pressure, and the mass flow rates of air and bioCNG. The parameters to analyse the mixture flow are pressure, velocity, turbulence, helicity and mass fraction of CH4. The mixture at the manifold outlet of the single-cylinder engine improved to average uniformity index of 0.9924, indicating better homogeneity. Further, the manifold of twin-cylinder engine attained the indexes of 0.1484 and 0.2401 for its two cylinders, showing non-homogeneity.

Predication of performance and emissions characteristics adual fuel engine energized with liquid and gaseous materials by Artificial neural network

The current study investigates the use of Artificial Neural Network (ANN) modelling for prediction of performance and emission characteristics biogas fuelled compression ignition engine under dual fuel mode. The biogas flow rate was varied from 1.2 to 3.2 kg/h while diesel fuel was injected as ignition source. The ANN model was developed to predict Brake Power (BP), Brake Specific Energy Consumption (BSEC), Brake Thermal Efficiency (BTE), Brake Specific Fuel Consumption (BSFC), Carbon Monoxide (CO), Carbon dioxide (CO2), and Hydrocarbons (HC) based on experimentation performed by varying load and biogas flow rates. In this study, ANN based models have been developed in the MATLAB2012a environment using the Neural Network toolbox, Back propagation algorithm, Levenberg- Marquardt Back propagation (TRAINLM), was used for the ANN structure for prediction of performance and emissions characteristics. There was a high correlation between the predicted values by the ANN model and the measured values resulted from experimental tests. The correlation coefficient was 0.99956 in the analysis of whole network when biogas and diesel were used, which implies that the model succeeded in prediction of the generator performance. It is found that the ANN modelling are good tools for prediction of performance and emission characteristics of biogas operated dual fuel diesel engine with varying engine operating loads and flow rates.

Effect of methane supplementation on the performance, vibration and emissions characteristics of methane-diesel dual fuel engine

The increasing energy demands, especially in transportation sector, and the challenges of excess pollution and environmental degradation caused due to the conventional fuels, as well as their limited availability has highlighted the need to look for alternative fuels to sustain future needs. Methane is capable of catering to these demands due to its wide availability, both in renewable and non-renewable energy sources. The present work explores the effect of methane supplementation on the performance and emission characteristics as well as the vibrations in internal combustion engines. A four-stroke compression ignition engine is modified to run as a methane-diesel dual fuel engine where methane is inducted through intake manifold and diesel is directly injected into cylinder. Tests are performed by varying engine load and methane energy levels up to 75%. Our study shows that the participation of methane at lower load conditions is weak due to its higher auto ignition temperature and higher calorific value. The emissions, particularly CO and NO, are observably higher at 75% load conditions due to the efficient combustion and higher temperature at higher load conditions. The vibration studies on the dual fuel combustion indicates that the introduction of methane also suppresses the frequency spectrum of combustion noise and reduces the ringing intensity level of vibration for complete spectrum of engine loads, with the effect being prominent at higher loads. Overall, our results suggests that combustion of methane in dual fuel diesel engine shows distinct characteristics at contrasting load conditions.

The combustion characteristics and performance of a Diesel Dual-Fuel (DDF) engine fueled by palm oil biodiesel and hydrogen gas

Investigation on the use of biodiesel produced from palm oil and hydrogen gas in diesel engines has been carried out. A single-cylinder diesel engine can be operated directly on palm oil biodiesel, and the manifold is then field with hydrogen at a flows of 2.5, 5, 7.5, and 10 lpm respectively. In this study, a single-cylinder diesel engine with a light load and a constant speed of 2000 rpm is used with a direct injection system. Therefore, this study aims to examine the combustion and performance characteristics of diesel engines, fueled by hydrogen gas and palm biodiesel. The cylinder pressure, the heat release rate, ignition delay, and knocking are explored as aspects of combustion. Additionally, thermal efficiency and fuel consumption are both factors that contribute to overall engine performance. The results at lower load showed that small hydrogen flow produced the lowest ignition delay at Diesel Dual-Fuel (DDF) of BH 2.5 lpm, and the lowest knocking at 10 lpm hydrogen flow. In addition, there was an average 27.38% increase in BTE and an average 47.61% decrease in Specific Fuel Consumption (SFC) compared to biodiesel.

Nitrogen Oxides and Ammonia Removal Analysis Based on Three-Dimensional Ammonia-Diesel Dual Fuel Engine Coupled with One-Dimensional SCR Model

Ammonia, as an alternative fuel for internal combustion engines, can achieve nearly zero carbon emissions. Although the development of the pure ammonia engine is limited by its poor combustion characteristics, ammonia–hydrocarbon mixed combustion can effectively improve the combustion of ammonia fuel. With the increase in the ammonia fuel proportion in the fuel mixture, a large number of nitrogen oxides (NOX) and unburned ammonia may be discharged, which have a poor impact on the environment. In this study, the performance of selective catalytic reduction (SCR) aftertreatment technology in reducing NOX and ammonia emissions from ammonia–diesel dual-fuel engines was investigated using simulation. A good cross-dimensional model was established under the coupling effect, though the effect of a single-dimensional model could not be presented. The results show that when the exhaust gas in the engine cylinder is directly introduced into the SCR without additional reducing agents such as urea, unburned ammonia flowing into SCR model is in excess, and there will be only ammonia at the outlet; however, if the unburned ammonia fed into the SCR model is insufficient to reduce NO, the ammonia concentration at the outlet will be 0. NOX can be 100% effectively reduced to N2 under most engine conditions; thus, unburned ammonia in exhaust plays a role in reducing NOX emissions from ammonia–diesel dual-fuel engines. However, when the concentration of unburned ammonia in the exhaust gas of an ammonia–diesel dual-fuel engine is large, its ammonia emissions are still high even after the SCR. In addition, the concentrations of N2O after SCR do not decrease, but increase by 50.64 in some conditions, the main reason for which is that by the action of the SCR catalyst, NO2 is partially converted into N2O, resulting in an increase in its concentration at the SCR outlet. Adding excessive air or oxygen into the SCR aftertreatment model can not only significantly reduce the ammonia concentration at the outlet of the model without affecting the NOX conversion efficiency of SCR, but inhibit N2O production to some extent at the outlet, thus reducing the unburned ammonia and NOX emissions in the tail gas of ammonia–diesel dual-fuel engines at the same time without the urea injection. Therefore, this study can provide theoretical guidance for the design of ammonia and its mixed-fuel engine aftertreatment device, and provide technical support for reducing NOX emissions of ammonia and its mixed fuel engines.

Development and validation of a reduced MF/biodiesel mechanism for diesel engine application

The 2-methylfuran (MF) is widely used as a surrogate fuel for internal combustion engines. However, the chemical kinetics model of MF for engine combustion simulations remains scarce. In this paper, a reduced MF/biodiesel mechanism consisting of 82 species and 226 reactions was proposed and used to simulate the combustion process of MF and biodiesel dual-fuel diesel engine. First, a detailed chemical reaction mechanism of MF was selected and then mechanism reduction methods were used to reduce the detailed mechanism under engine conditions. Second, the reduced MF mechanism was coupled with a biodiesel mechanism to form a four-component chemistry mechanism, consisting of MD, MD9D, n-heptane, and MF. Third, the combined mechanism was optimized by using rate of production analysis and sensitivity analysis. Finally, the proposed four-component mechanism was verified by comparing the calculated values of ignition delay and species concentrations with the experimental values. Meanwhile, a new dual-fuel diesel engine test was carried out, and the experiments were used to evaluate the reliability of the combination mechanism. Overall, the simulated results of the proposed four-component mechanism in this paper are basically consistent with the experimental results.

A review on performance and emission characteristics of a diesel engine fueled with gaseous & liquid fuels

There is a growing need for alternative fuels because of growing concerns about the environmental harm caused by the usage of fossil fuels. In an effort to reduce energy use, a number of research have been conducted. It is widely accepted that biofuels derived from biomass are a viable alternative to petroleum-based fuels. Biogas, a biomass-derived fuel, is suitable for use in internal combustion engines due to its superior air mixing ability and clean burning qualities. In comparison to other secondary fuels, biogas is less costly and emits fewer pollutants because of anaerobic digestion of a variety of organic materials like kitchen trash, agricultural waste, municipal solid waste and so on, being the process through which it is produced. As part of this investigation, biogas usage is reviewed in case of dual fuel engines. Diesel & biogas dual fuel diesel engines have been proven to emit less hydrocarbons (HC), smoke and particulate matter than conventional diesel engines. A complete literature study is conducted for establishing emission, combustion & performance characteristics for biogas combustion for CI engines.

TEMPERATURE EXHAUST GAS ANALYSIS ON THE SHIP ENGINE

Dual-fuel diesel engine is an engine with the use of two fuels in the combustion process to get labor on the engine. The types of fuels used include methane gas and marine gas oil fuels. Methane is produced from vapor cargo tank liquified natural gas. The purpose of this study was to determine what causes high exhaust gas temperatures on the performance of the dual-fuel diesel engine using the fault tree analysis data analysis method. From the analysis of the research data, several problems were formulated, namely, the factors that could cause high exhaust gas temperatures in the dual fuel diesel engine were the lack of combustion air supply in the engine combustion chamber, incompatible combustion composition between oil and gas fuel, and the engine room that is extremely hot. The impact caused is damage to the machining components and decreased performance of the dual-fuel diesel engine. To overcome the decrease in work on the dual fuel diesel engine is to carry out maintenance and repair on every component of the engine that has problems and damage in accordance with standard procedures.

천연가스 이중연료 디젤엔진의 모드별 유해배출가스 성능에 관한 연구

Emission data were acquired during sailing in order to demonstrate the emission reduction of dual fuel diesel engines mounted on ships in this study. CO, CO2 and NOx were acquired while sailing Cheonghwa 2 of the Korea Marine Environment Management Corporation in diesel mode and gas mode, and acquisition data was compared and reviewed with the data of the NOx Technical File. As a result, NOx was emitted slightly less while CO2, CO and THC were emitted more on sailing than NOx Technical File data. Comparing the diesel mode and the gas mode, CO2 and NOx were less emitted, while CO and THC were emitted more in the gas mode. In the future, it is necessary to continuously secure data according to the age.

Investigation on the performance and emissions of tri-ethylene glycol mono methyl ether with hydrogen as a secondary fuel in dual fuel diesel engine

The utilization of hydrogen as a gaseous fuel in CI engines in dual fuel mode, has gained significant interest due to its clean-burning nature, high energy share, and higher availability in nature. In this experimental study, hydrogen was used as a secondary fuel along with tri-ethylene glycol mono methyl ether (TGME) as a fuel additive in diesel to investigate the effects on the engine performances and emissions using a modified duel fuel diesel engine (power of 3.5 kW at 1500 rpm). It revealed that addition of hydrogen (30–35%) enhanced the brake thermal efficiency of the engine at each load conditions, but in accordance it also reduces with the lower hydrogen (15–25%). Reduction in oxides of nitrogen was observed with the hydrogen insertion up to 50% load while carbon mono oxide, carbon dioxide and un-burnt hydrocarbon were significantly reduced at entire load conditions. Further, the addition of fuel additive (TGME) enhanced the brake thermal efficiency at each loads. A reduced ignition delay was also observed by the inclusion of TGME and hydrogen due to pre-ignition of the fresh charge. Moreover, this study concluded that addition of 1% fuel additive in diesel with 25% of hydrogen at 30% load, performance and emissions were optimum.

Effects of piston shape and nozzle specifications on part-load operation of natural gas–diesel dual-fuel RCCI engine and its application to high load extension

• Effects of piston shape and multi-angle nozzle were evaluated for DF RCCI operation. • Enhanced air utilization w/multi-angle nozzle reduced combustion and HT losses. • The highest GIE of RCCI improved as 51.8 % by hardware modifications. • Intake air amount could be increased by lowering CR (from 17 to 15) at the maximum load. • The maximum load of RCCI could be extended from 81 (reference) to 101 kW of BP. In this study, the effects of modifications of both the piston shape and injector nozzle are experimentally investigated for high load extension of a natural gas–diesel dual-fuel reactivity-controlled compression ignition (RCCI) engine. First, a bathtub shape with a reduced compression ratio is applied to the modified piston which was reported to improve the flame propagation in squish volume, the cooling loss, and the air induction rate under the same limit of in-cylinder pressure from previous studies. In addition, a multiangle two-layer injector is used to extend the maximum load, which has been proven to be effective for unburned hydrocarbon emissions and gross indicated efficiency in part-load operation in our previous study. The experiments are conducted under both 1200 rpm part-load operation (approximately 1950 J/cylinder per cycle of fuel input energy) and 1800 rpm maximum load operation. The objectives are to comprehensively evaluate the effects of the modifications on natural gas–diesel RCCI operation and verify the effects of all load conditions. The experimental results reveal that the changes in the piston—reduction in the compression ratio and a bathtub piston shape—are effective for both NOx and smoke emissions as the diesel injection timing is advanced. Although the multi-hole double layer (combined narrow and wide injection) has less effect on emissions compared to that of the change in piston, it affects the mixing process inside the cylinder, thus retarding the combustion phasing, prolonging the combustion duration, and eventually reducing the cooling loss. Both modifications are highly effective for advanced diesel injection timing corresponding to RCCI operation, which extends high-load operation from 80.9 to 101 kW of brake power, relatively 24.8 % increase, by adopting both the piston and injector modifications. Based on the modifications, the mass fraction of natural gas is suggested to be approximately 80 %. A higher fraction causes the variation in the maximum in-cylinder pressure to be extremely sensitive to allow robust operation. In contrast, if it is lower, the amounts of both NOx and smoke emissions exceed the emission standard levels (0.4 g/kWh and 15 mg/kWh for NOx and smoke emissions, respectively, corresponding to Stage-V of non-road engine operation).

A Study on LPG injection based speed regulator for dual fuel diesel engine

Diesel engines are popularly interested due to their great economic efficiency and the high amount of harmful emissions released. The conversion of using multi-fuel engines aims to reduce emissions, and diversifying alternative energy sources to replace diesel fuel, is a potential solution. This paper presents a method to convert the fuel system of the DI-diesel engine type Vikyno RV125 to LPG-diesel dual combustion mode and preliminarily evaluate performance characteristics operating with the LPG injection-based speed regulator. An LPG injector controller circuit was actuated to operate the engine with different load modes up to 5.0kW at corresponding engine speeds. The air intake manifold was modified to calibrate the air-mass flow to effective performance. The experimental result revealed that the changed system could operate in LPG-diesel dual combustion mode. The operating stability of the engine was recognized at speeds up to 1600rpm. A study on engine exhaust emissions will be performed in the next research stage.