N-butanol Blends Research Articles

Investigations on N-Butanol and Biodiesel Blends Performance in Stationary Engine

Investigations on N-Butanol and Biodiesel Blends Performance in Stationary Engine

Combustion characteristics of RP-3 aviation kerosene/n-butanol blended fuel in a compression ignition engine

In order to meet the requirements of Sustainable Aviation Fuel (SAF) to achieve the imperatives of energy conservation and emission reduction. This paper compares the combustion characteristics of diesel, RP-3/n-butanol blends in terms of heat release rate, in-cylinder pressure, temperature and fuel economy in a compression ignition engine, taking into account the advantages of lightweight structure, low fuel consumption and wide range of applications of aviation piston engines. The results certified the viability of applying RP-3 and RP-3/n-butanol blends in diesel engines. Adding n-butanol prolonged the ignition delay and shorten the combustion duration. Moreover, the peak of the pressure, temperature and apparent heat release rate (AHRR) increased. In addition, the blended fuel showed obvious diffusion combustion characteristics at high load. With the n-butanol increased, the combustion instability of the blended fuels decreased significantly, at low load. At n = 2400r/min, pme = 0.53 MPa, compared with diesel, the maximum heat release rate (MHRR) of R70B30 increased by 76.6 %, improving the combustion characteristics of the blended fuel. Moreover, the equivalent specific fuel consumption (ESFC) of RP-3 is 5.56–14.83 % lower than that of diesel, and the effective thermal efficiency (ETE) of RP-3 is 2.8–13.46 % higher than that of diesel under most working conditions.

Performance and emission characteristics of novel biodiesel-diesel blends: an RSM and ANN approach

Abstract In this paper, the impact of different input variables on the performance and emission features of a pongamia pinnata and rapeseed oil biodiesel with n-Butanol additive were investigated, statistically analyzed, and optimized by employing the powerful response surface methodology (RSM) based design of experiment (DOE) techniques. The vegetable oils (pongamia pinnata and rapeseed oils) were transesterified and their corresponding methyl esters were blended with diesel and n-Butanol at blend ratios 10:84:6, 10:78:12, 20:74:6 and 20:68:12. The samples were tested on a direct injection CI engine at a rated speed of 1500 rpm and standard CR of 17.5:1 at different loads. In each test, performance and emission parameters were measured. Expert machine learning (ML) methods were used to forecast these features. In addition, polynomial equations were developed for each blend using regression techniques and compared with an artificial intelligence technique. It was observed that the engine performance increased as biodiesel and additive weight percentage increased. Regardless of the loads placed on the engine and the blend ratios, the use of PPME and RSME combined with n-Butanol blends demonstrated a clear decrease in NOx compared to diesel (7.07% for P20B12 and 6.58% for R20B12). As per the trend, it is seen that the percentage reduction in CO2 emissions is greater with high percentage increase of n-Butanol in the tested sample irrespective of loads applied on the engine (2.95% more P20B12 for as compared to P20B6). For the emission characteristics, ANN demonstrated a range of 87.92% to 98.83% prediction accuracy while that of regression varies from 81.4% to 98.8% for all the samples of PPME blended biodiesel.

Synergic effect of hydrogen and n-butanol on combustion and emission characteristics of a hydrogen direct injection SI engine fueled with n-butanol/gasoline

Hydrogen, an ideal carbon-free energy carrier with favorable combustion properties, has drawn worldwide attention as a high-expectation way to enhance fossil fuels’ combustion performance. However, currently, limited investigations are about enhancing n-butanol hybrid gasoline engines through hydrogen addition. Thus, in this paper, the hydrogen direct injection (HDI) was put forward to improve an SI engine fueled with n-butanol/gasoline, and the synergic effect of hydrogen and n-butanol on combustion and emission characteristics was studied. Experimental results indicated the favorable influence of a low n-butanol mixing ratio (νN, νN = 25%) on enhancing combustion can relatively weaken the similar promoting effect of hydrogen. And the sequential increase in hydrogen addition ratio (φH, φH = 15–20%) can compensate for the negative impact of unfavorable atomization and vaporization quality caused by higher n-butanol blending (νN = 75–100%), namely the usage amount of n-butanol in engine can be raised. Further, compared with pure gasoline, the percentage change in BMEP (brake mean effective pressure) at νN = 25% and 100% can be increased from 1.79% to 5.04% and −5.38%–2.01% respectively by φH from 0 to 20%. Besides, the HDI can also shorten the combustion duration, accelerate the heat release process and improve the combustion stability of each νN, while the amplitude of promotion exhibits a relative downtrend with the increase of φH. As for emission characteristics, the HC, CO and particulate emissions decreased monotonously with the increasing φH under all νN, but there was a visible increase in NOX emissions.

Experimental Investigation on the Effect of TiO2 Nanoparticles Emulsion in Water on Emissions and Performance Characteristics of DI Diesel Engine

The world is presently confronted with the twin crisis of resource restriction and environmental degradation. The search for solutions that promise a harmonious correlation with sustainable development, energy conservation, efficiency, and environmental preservation has become highly important. The main purpose of innovative studies on fuel refinement and combustion engines is to improve fuel properties by adding fuel additives. In this study, the impact of Titanium dioxide, TiO2, nanoparticles solution blended with diesel fuel on the performance and emission characteristics of four-stroke combustion engine OM 364 EU III, manufactured by IDEM Co and licensed by Daimler Benz, has been investigated. The selection of TiO2 nanoparticles is based on the easy access in the market and the gap recognized; in previous literature, these nanoparticles were added to biodiesel or n-butanol blends. The proposed combined fuel in this study contains 2.5 ppm TiO2 nanoparticles dissolved in 1200 [ml] water and added to 60 [Lit] base diesel fuel. The results of the aforementioned combined fuel have been compared with the base diesel fuel. It has been observed that applying nano-additives improves the mechanical performance of the diesel engine, such as power, torque, brake-specific fuel consumption, and thermal efficiency. Moreover, soot, unburned hydrocarbons, and carbon monoxide have declined by 2.78%, 3.55%, and 3.32%, respectively, due to TiO2 nanoparticles' catalytic effect on fuel combustion. However, the amount of NOx has increased up to 3.09% because of the high cycle temperature.

Numerical study on the combustion and emission characteristics of a direct injection natural gas engine ignited by diesel/n-butanol blends

Adjusting the composition of pilot fuel has been regarded as an effective method for the improvement of performance and emissions of pilot ignited direct injection natural gas engines. In this paper, the effects of employing diesel/n-butanol blends as the pilot fuel in a direct injection natural gas engine were assessed by numerical simulations. The results indicated that adding n-butanol into the pilot fuel will result in notable extensions in ignition delay and obvious reductions in combustion duration at low and medium engine loads; at high engine loads, the effects of n-butanol blending on combustion parameters are relatively small. In terms of engine performance, thermal efficiency could be improved by up to 2.3% and 6.5% by adding n-butanol into the pilot fuel at low and medium engine loads, whereas lower than 2% reduction in thermal efficiency would be induced by n-butanol addition at high engine load. With regard to emissions, more than 30% reductions in CO and soot emissions could be achieved by adjusting n-butanol blending ratio at low and medium engine loads; at low and high engine loads, blending n-butanol into the pilot fuel is favorable for the control of NOx emissions while at medium engine load, n-butanol blending could result in up to 34.7% increases in NOx emissions.

Effects of Alcohol-Blended Waste Plastic Oil on Engine Performance Characteristics and Emissions of a Diesel Engine

The current study aims to investigate and compare the effects of waste plastic oil blended with n-butanol on the characteristics of diesel engines and exhaust gas emissions. Waste plastic oil produced by the pyrolysis process was blended with n-butanol at 5%, 10%, and 15% by volume. Experiments were conducted on a four-stroke, four-cylinder, water-cooled, direct injection diesel engine with a variation of five engine loads, while the engine’s speed was fixed at 2500 rpm. The experimental results showed that the main hydrocarbons present in WPO were within the range of diesel fuel (C13–C18, approximately 74.39%), while its specific gravity and flash point were out of the limit prescribed by the diesel fuel specification. The addition of n-butanol to WPO was found to reduce the engine’s thermal efficiency and increase HC and CO emissions, especially when the engine operated at low-load conditions. In order to find the suitable ratio of n-butanol blends when the engine operated at the tested engine load, the optimization process was carried out by considering the engine’s load and ratio of the n-butanol blend as input factors and the engine’s performance and emissions as output factors. It was found that the multi-objective function produced by the general regression neural network (GRNN) can be modeled as the multi-objective function with high predictive performances. The coefficient of determination (R2), mean absolute percentage error (MAPE), and root mean square error (RSME) of the optimization model proposed in the study were 0.999, 2.606%, and 0.663, respectively, when brake thermal efficiency was considered, while nitrogen oxide values were 0.998, 6.915%, and 0.600, respectively. As for the results of the optimization using NSGA-II, a single optimum value may not be attained as with the other methods, but the optimization’s boundary was obtained, which was established by making a trade-off between brake thermal efficiency and nitrogen oxide emissions. According to the Pareto frontier, the engine load and ratio of the n-butanol blend that caused the trade-off between maximum brake thermal efficiency and minimum nitrogen oxides are within the approximate range of 37 N.m to 104 N.m and 9% to 14%, respectively.

Application of Taguchi design in optimization of performance and emissions characteristics of n-butanol/diesel/biogas under dual fuel mode

Combustion experts are in search of some alternative fuel from last few decades owing to diminishing petroleum products and unexpected variations in habitat, which are result of venomous emissions from the CI engines. The present investigation intended to assess the performance and emission parameters of a diesel engine by fueling it with pilot fuel (blends of diesel and n-butanol) and primary fuel (Biogas). Results revealed that BTE, HC and CO increases whilst NOx and smoke emissions were reduced by using the pilot and primary fuel together in relation with natural diesel. Experimentation was done using Taguchi L9 orthogonal array design. The engine load, flow rate of biogas and butanol in fuel blend percentage were selected as input parameters whereas brake thermal efficiency (BTE) and emission characteristics i.e., HC, CO, NOx and smoke were chosen as response variables. ANOVA was carried out for the responses by utilizing MINITAB software. The higher value of raw data and S/N ratio for BTE was noted with high engine load, low flow rate of biogas and butanol blend percent. For the emission characteristics i.e., HC, CO and smoke, lower raw data and high S/N ratio values were attained in the order of rank engine load > butanol blend percent > biogas flow rate while the similar values for NOx were attained in the rank engine load > biogas flow rate > butanol blend percent. Taguchi design was noted to be an effective tool for the optimization of various response parameters and the optimum levels of input parameters were calculated after analysis. Full engine load for BTE and HC, Biogas flow rate of 15 lpm for BTE, HC and CO, and 20 % of butanol blend for HC, CO and smoke were found to be the optimum conditions for the conducted experimentation.

Effect of n-Butanol Addition to Diesel Fuel on Reduction of PAH Formation and Regulated Pollutants

The primary motivation of this paper is to report the effects of n-butanol addition (5, 20 and 35% by volume) to diesel fuel on regulated and polycyclic aromatic hydrocarbon (PAH) emissions of a diesel engine. PAH samples were quantified using rigorous analytical chemistry procedures to determine total PAHs, PAH dispersion and PAH toxicity. In comparison with diesel fuel, all n-butanol blends (DBu5, DBu20, and DBu35) reduced nitrogen oxides (NOx) emissions by 6.77%, 9.59%, and 20.08% and total PAH emissions by 66.86%, 75.33%, and 80.98%. In terms of the relative distribution of PAHs, a significant decrease was recorded in higher cyclic PAHs such as Pyrene, Benzo[a]anthracene, Chrysene, Benzo[k]floranthene, Benzo[a]pyrene for all blends. Similarly, the amount of the toxicity of the PAH emissions also decreased by 11.66%, 87.53%, and 67.28% with DBu5, DBu20 and DBu35 blends, respectively. With the addition of n-butanol to the diesel fuel, total PAH emissions were detected below the Occupational Safety and Health Administration’s (OSHA)-Permissible Exposure Level. Overall, it was demonstrated that n-butanol addition to diesel fuel significantly reduced PAH formation which is helpful to prevent wet stacking, and prolong the operating time of the diesel engine especially at low loads or cold operating conditions.

Diesel blends with high concentrations of biodiesel and n-butanol: Effects on regulated pollutants and polycyclic aromatic hydrocarbons

Despite advances in alternative energy production (including electric vehicles and hydrogen fuel cells), fossil fuels remain ubiquitous and an ongoing threat to the environment. Alternative biofuels such as biodiesel and n-butanol have garnered substantial attention in recent years as additives to fossil diesel as a means to control emissions such as nitrous oxides (NOx) and carbon monoxide (CO). In addition, as biodiesel and alcohols do not contain aromatic hydrocarbons in their chemical structures, they provide potential additional advantages for reducing toxic emissions, including polycyclic aromatic hydrocarbons (PAHs); however, this is often only demonstrated for relatively low blend ratios (<20 %). In this study, the effects of neat diesel, waste oil biodiesel, and n-butanol blends on engine function, regulated, and unregulated emissions were investigated for blends containing 50/50 vol% diesel/biodiesel (D50B50), 50/25/25 vol% diesel/biodiesel/n-butanol (D50B25Bu25), and 50/50 vol% diesel/n-butanol (D50Bu50), in addition to neat standard road diesel (D100) and waste oil derived biodiesel (B100). In these blends NOx was reduced by up to 28.1 % relative to D100 for loads above idle, while increasing exhaust gas temperatures up to 33.5 % and increasing unburned hydrocarbons (HC) and CO by up to 84.2 % and 93.8 %, respectively. Measured against neat diesel, biodiesel and the diesel-biodiesel-butanol blend reduced PAH toxicity by up to 46.4 %, while diesel-biodiesel and diesel-butanol blends showed an increase up to 14.3% and 504%, respectively, due to higher concentrations of 5-ring PAHs. It has been concluded that in addition to fuel aromaticity, other factors such as fuel properties affecting the diesel combustion process (i.e. cetane number), can cause PAH formation.

Experimental and numerical study of soot volume fraction and number density in laminar co-flow diffusion flames of n-decane/n-butanol blends

Normal decane was selected as a surrogate fuel for RP-3 aviation fuel, and soot formation characteristics and effects of n-decane (D) /n-butanol (B) cofiring were investigated experimentally and numerically. Combustion experiments of six n-decane/n-butanol blends (i.e., D100, D80, D60, D40, D20, D00, indicating the volumetric fraction of n-butanol in blends) were performed on co-flow diffusion flames. The volume fraction and morphological characteristics of soot at different heights of the flame axis were obtained using thermophoretic sampling and transmission electron microscopy analysis. A newly developed n-decane/n-butanol/PAH kinetic model consisted of 73 species and 275 reactions were further applied to model the soot formation process and ascertain the effects of n-butanol blending. Experimental and simulation results showed that soot loading (soot volume fraction and number density) decreased with increasing n-butanol blending ratios. Chemical kinetic analysis suggested that n-butanol addition decreased the rate of the HACA reaction as a result of a reduction of C2H2 and C2H3 (+M) ⇄ C2H2 + H (+M), ultimately leading to a reduction of soot loading.

Combustion reaction kinetics of biodiesel/n-butanol blends: Experiments in an ultrahigh-pressure rapid compression machine

Burning oxygenated hydrocarbon biofuels in engines is a viable path for saving energy and reducing carbon emissions. N-butanol and biodiesel are two representative biofuels and have attracted widespread interest. In this study, the blends of n-butanol and biodiesel (a waste cooking oil) with different n-butanol ratios (40%, 60%, 80% by volume) were adopted to study their autoignition characteristics in a newly developed ultrahigh-pressure rapid compression machine. The ignition delay times of the blends were precisely measured under wide pressures of 10/20/40/60 bar, equivalence ratios of 0.3/0.5/1.0, and a temperature range of 700–970 K. Experimental results show that the ignition delay time decreases with the increase of pressure and equivalence ratio at the investigated conditions regardless the blending ratios. It is also found that the ignition delay time becomes slightly longer with the increasing n-butanol ratio in the blends at temperatures below 820 K. However, as the temperature further increases, the ignition delay times of different blends get closer and has a crossover tendency. The composition of the biodiesel was quantitively analyzed and a surrogate fuel was developed. An optimized mechanism was proposed based on a documented detailed mechanism with 461 species and 18,217 reactions. Simulation results show that the optimized mechanism better captures the dependence of the measured ignition delay times on temperature, pressure, and blending ratios over the entire temperature range compared to the original mechanism. In the end, species evolution and sensitivity analysis were performed sequentially with the optimized mechanism to give kinetics insight into the chemical interaction between biodiesel and n-butanol. The experimental data and modeling results reported here provide a basis for understanding the combustion reaction kinetics of biodiesel/n-butanol blending fuels.

Fuel effects on PAH formation, toxicity and regulated pollutants: Detailed comparison of biodiesel blends with propanol, butanol and pentanol

Blends of biodiesel and high-carbon alcohols have the potential to increase the rate of biofuel use in diesel engines, while reducing harmful and toxic compounds such as polycyclic aromatic hydrocarbons (PAHs). Since biodiesel and alcohols do not contain aromatic ingredients in their chemical structures, this study examined biodiesel blends with propanol, n-butanol, and 1-pentanol (5 %, 20 % and 35 % by vol.) and the effects of these aromatic-free fuels on regulated emissions, PAH formation and toxicity as compared to straight diesel fuel in a diesel engine operating at a constant speed and varying engine loads. PAH samples were meticulously processed and extensively analyzed using rigorous analytical chemistry methodology (gas chromatography–mass spectrometry (GC–MS)). Biodiesel and biodiesel-alcohol blends significantly reduced NOx emissions and the level of formation of PAHs and toxicity levels when compared to diesel fuel. Overall, adding 5 % alcohol to biodiesel decreased total PAH emissions. However, with the exception of 20 % propanol, adding 20 % and 35 % alcohol to biodiesel increased total PAH emissions as compared to neat biodiesel. In contrast, all blended fuels resulted in a decrease in the toxicity of PAH compounds (up to 70 %) and the percentage of higher-ring PAHs. Among higher alcohols, propanol blends stood out as reducing PAH formation as compared to n-butanol and pentanol blends. Overall, biodiesel-alcohol blends that emit less carcinogenic pollutants and primarily low-rings PAHs were found to be advantageous for reducing the likelihood of wetstacking in diesel engines under low load or cold operating conditions.

N-Butanol or isobutanol as a value-added fuel additive to inhibit microbial degradation of stored gasoline

Biofouling of gasoline can occur during fuel storage caused by bacteria and fungi that form a biofilm at a fuel/water interface and that produce organic acids and sulfides. Fuel additives are applied to gasoline to prevent biofouling but are relatively expensive, are not always effective against biofilms, and do not contribute to the combustibility of gasoline. Bio-isobutanol is an approved, certified advanced biofuel and is added up to 16% (v/v) in gasoline blends “iBut16”; n-butanol blends are currently under review. Microorganisms are inhibited by n-butanol or isobutanol when the aqueous concentration reaches >2-3% (w/v). We determined that n-butanol partitions into the aqueous phase of a model gasoline/water system reaching concentrations of 42 g/L and up to 48 g/L from gasoline blends at 10% and 24% (v/v), respectively. Likewise, isobutanol blended in gasoline at 10% and 24% (v/v) partitioned into an aqueous phase at 45 g/L and 53 g/L, respectively. Several bacterial and fungal strains that originate from fuel storage tanks, or are known to be solvent tolerant, were evaluated for their potential growth in a range of n- and isobutanol concentrations. Growth rates for all strains tested were reduced by 40–100% relative to untreated controls in n- and isobutanol concentrations of 1.5 and 2.0% (v/v). No observable growth occurred for any of the microorganisms in solvent concentrations at 3.0% (v/v). T amphiphilic and chaotropic properties of n- or isobutanol help them inhibit microbial growth and could serve as effective biocides during fuel storage as well as being valuable fuel additives.

Formation of polycyclic aromatic hydrocarbons and regulated emissions from biodiesel and n-butanol blends containing water

To increase the use of biofuels in diesel engines and reduce harmful emissions emitted from diesel fuel, biodiesel and higher alcohols are fuel sources at the forefront of research. The aim of this study is to understand the effect of water-containing n-butanol-biodiesel blends on regulated emissions, emphasizing nitrogen oxides (NOx) and polycyclic aromatic hydrocarbons (PAHs), which are harmful for the environment and engine durability. 10% n-butanol (B90Bu10) and 10% n-butanol-1% water (B89Bu10W1) were blended with 89% waste-oil biodiesel and tested in a diesel engine at four engine loads at a constant engine speed. PAH samples were analyzed using gas chromatography-mass spectrometry (GC-MS). Results showed B100, B90Bu10 and B89Bu10W1 blends increased break specific fuel consumption (BSFC), exhaust gas temperatures (EGT), carbon monoxide (CO) and hydrocarbon (HC) emissions. However, NOx emissions significantly decreased using butanol and butanol-water blends. Compared to diesel, biodiesel and blended fuels significantly reduced total PAHs and PAH toxicity up to 75.0%. However, B89Bu10W1 increased total PAH and PAH toxicity by 35.7%. Overall, the biodiesel-butanol blend, which emits less carcinogenic pollutants and low-cyclic PAHs than water-containing fuel, was found to reduce the risk of wetstacking in diesel engines operating under low loads.

Influence of injection timing on performance, combustion and emission characteristics of a diesel engine running on hydrogen-diethyl ether, n-butanol and biodiesel blends

In the present research, 5% hydrogen was added to 95%diesel fuel, diethyl ether (DEE), n-butanol (nB), and spirulina microalgae in this investigation (SMA). The fuels were then tested using a numerical tool and the Diesel RK-Model programme in a single cylinder CI engine. The results showed that the 5%H95%DEE blend consistently showed the highest level of specific fuel consumption (SFC) with increasing trend as the injection timings was advanced. In terms of brake thermal efficiency (BTE), all blends experienced decreasing trend except for 5%H95%nB. The addition of 5% hydrogen into 95% n-butanol gave relatively stable level of BTE for the entire injection timings. Furthermore, all blends witnessed relatively the same exhaust gas temperature (EGT) trend with only minor changes. Not much significance was observed from the most retarded to the most advanced injection timing. In terms of peak in-cylinder pressure, all the investigated blends saw increasing trend with the advancing injection timing. However, they experienced slight reduction at the most advanced fuel injection timing (FIT). Except for 5%H95%SMA, all blends show the highest peak in-cylinder pressure at 26.5 deg. before TDC. With regards to the ignition delay (ID), 5%H95%nB always gave the longest ID except at the 29.5 deg. before TDC, while the 5%H95%DEE consistently showed the shortest ID with nearly the same value for all Its at around 1.8–3.1 deg. Regarding the emissions, the use of n-butanol (5%H95%nB) consistently produced the lowest CO2, smoke, NOX, and particulate matter (PM) emissions throughout the entire injection timings.

Numerical analysis of soot emissions from gasoline-ethanol and gasoline-butanol blends under gasoline compression ignition conditions

In the present work, computational fluid dynamics (CFD) simulations of a single-cylinder gasoline compression ignition (GCI) engine were performed to investigate the impact of blending two biofuels, ethanol and n-butanol, with gasoline on the trade-off between combustion phasing and soot emissions under low load conditions. In order to represent market gasoline (RD5-87), a four-component toluene primary reference fuel (TPRF) + ethanol (ETPRF) surrogate (with 20% ethanol by mole; E20) was formulated using a neural network based octane predictor such that the surrogate had the same ethanol content, Research Octane Number (RON) and Octane Sensitivity (S). In addition, a novel skeletal kinetic mechanism for ETPRF and TPRF + n-butanol (BTPRF) blends, incorporating polycyclic aromatic hydrocarbon (PAH) chemistry, was developed. A three-dimensional (3D) engine CFD formulation employing the skeletal mechanism, adaptive mesh refinement (AMR), finite-rate chemistry approach, and hybrid method of moments (HMOM) was adopted to capture the in-cylinder combustion phenomena and soot emissions. The engine CFD model was validated against RD5-87 experimental data for a broad range of start-of-injection (SOI) timings (-21/-27/-36/-45 crank angle degrees (CAD) after top-dead-center (aTDC)), with respect to in-cylinder pressure, heat release rate, combustion phasing, and soot emissions. The closed-cycle simulation results were analyzed to elucidate the non-monotonic trend of soot emissions versus SOI timing: SOI-36 > SOI-45 > SOI-21 > SOI-27. Thereafter, the validated CFD model was employed to simulate the combustion of a gasoline-ethanol blend with 45% (by mole) ethanol (E45) and a gasoline-butanol blend with 45% (by mole) n-butanol (B45) under the same operating conditions to study the effects of fuel composition and SOI timing on combustion phasing and soot emissions. The sooting propensity followed the trend: B45 > E20 > E45 at all SOI timings. Overall, it was observed that the autoignition propensity was primarily related to fuel chemistry. On the other hand, sooting propensity showed strong coupling with both fuel chemistry and physical properties, with greater impact of fuel physical properties at advanced SOI timings.

Performance, combustion and emission characteristics investigations on a diesel engine fueled with diesel/ ethanol /n-butanol blends

In this study, a three-dimensional computational fluid dynamics (CFD) model of a diesel engine cylinder was developed by AVL-Fire software, and a chemical reaction mechanism containing 377 reactions and 81 species was established by the CHEMKIN program. The purpose of this work is to investigate the effect of diesel/ethanol/n-butanol blends on combustion and emission characteristics such as in-cylinder pressure, in-cylinder temperature, brake power, brake thermal efficiency, brake specific fuel consumption, NOx emission, CO emission and soot emission. The results showed that the diesel/ethanol/n-butanol blended fuels reduced the brake power and increased the brake specific fuel consumption of the diesel engine, but improved the brake thermal efficiency. In addition, the blend fuels reduced nitrogen oxides, carbon monoxide, and soot emissions. At 100% load, when the diesel engine fueled with E5N13, E10N5, E10N18, E15N10, E15N18, and E20N10, the brake thermal efficiencies were increased by 2.72%, 2.69%, 4.52%, 4.49%, 5.565%, and 5.53% respectively. However, the brake specific fuel consumption increased by 2.79%–5.84%, and the brake power decreased by 2.76%–5.59%. At 50% load, blended fuels with different mixture ratios reduced nitrogen oxides by 8.39%–21.81%, carbon monoxide by 12.1%–22.91%, and soot by 26.71%–48.59% compared to diesel. This is influenced by a combination of higher oxygen content, lower cetane number and calorific value of ethanol and n-butanol.

Investigation of diesel/n-butanol blends as drop-in fuel for heavy-duty diesel engines: Combustion, performance, and emissions

This study focused on the application of a single-zone combustion model together with triple Wiebe functions to analyze the impact of the diesel/n-butanol blends as drop-in fuel in a four-cylinder heavy-duty diesel engine (HDDE). Commercial diesel (EN590) was used as a reference fuel to compare combustion, performance, and emissions characteristics with n-butanol blends of 5%, 10%, and 20%, by volume (DBu5, DBu10, and DBu20) under different speed and load conditions as per the World Harmonized Steady-State Cycle (WHSC). The apparent heat release rate (AHRR) calculated from the model agrees (RMSE ≤ 6.80) with the experimental values. The results show that the DBu5 and DBu10 blend increase maximum in-cylinder pressure and maximum AHRR while the in-cylinder temperature slightly decreases, at low load, without significant changes in ignition delay and combustion duration. The DBu20 blend reduced maximum in-cylinder pressure, maximum AHRR and in-cylinder temperature in all operating conditions, in addition, increased the ignition delay and reduced the combustion duration. Brake specific fuel consumption (BSFC) increases by 0.8–6% with an increase in n-butanol content; however, the addition of n-butanol reduced the brake specific energy consumption (BSEC) by 1.7–2.3%. All n-butanol blends reduced CO and particle emissions, regardless of operating conditions, while THC and NOX emissions increased mainly at full load. DBu10 blend showed better engine performance along with combustion and emission characteristics, which makes it a promising fuel blend as per the current study.

Comparison of volatility characteristics and temperature-dependent density, surface tension, and kinematic viscosity of n-butanol-diesel and ABE-diesel fuel blends

Climate strategies and targets are impossible to meet with the continuously expanding energy and transportation sectors without renewable liquid fuels. Butanol is a potential alternative fuel, however, its production cost is currently high. Therefore, acetone-butanol-ethanol (ABE), an intermediate fermentation product, can also be used as fuel, which is economically more competitive. This paper provides temperature-dependent measurement data of material properties of various n-butanol and ABE blends with EN 590 diesel fuel. The key findings are the following. Distillation curves and initial boiling points match up to 25% volume fraction of biofuel for n-butanol and ABE blends. Initial boiling point decreases exponentially with biofuel content and has no considerable change above 25% and 50% biofuel volume fraction for n-butanol and ABE blends, respectively. Curve fitting was performed for initial boiling point, density, surface tension, and kinematic viscosity data to provide an empirical model for simulations. The simple mixing rule was applicable to density and surface tension. Nissan-Grunberg equation for viscosity is only recommended with the binary interaction parameter that is negative for n-butanol and positive for ABE blends. Ohnesorge number has a minimum at 25% n-butanol volume fraction, showing a minimum in average droplet size, which is optimal for clean operation.