N-butanol Blends Research Articles

Combustion performance and emission characteristics of a diesel engine burning biodiesel blended with n-butanol

The combustion and emission characteristics of a four-cylinder direct injection diesel engine fueled with 0%, 10%, 20% or 30% blends of n-butanol and biodiesel were characterized at the loads of 0.13–1.13 MPa brake mean effective pressure (BMEP) and the speed of 1800 rpm. With the main injection time and rotation speed constant in the bench test, the cylinder pressure, heat release rate, ignition delay and the regulated or unregulated emissions were measured. The peak of HRR maximized at 0.38 MPa BMEP. The ignition delay period was prolonged in the case of n-butanol. But the combustion duration was shorten with the rising of n-butanol ratio. When n-butanol was added, more HC, NOx and acetaldehyde and less CO, 1,3-butadiene and benzene were emitted. For soot emissions, the addition of n-butanol would reduce the formation of soot. In conclusion, the addition of n-butanol improves the combustion performance while there has different changes about emission characteristics.

Effects of using alcohols on the performance and emissions of a diesel engine

Addition of renewable alcohols to diesel is being investigated extensively to reduce greenhouse gas emissions. The objective of this study was to examine the suitability of such renewable alcohols. In this study, emissions and performance characteristics of alcohol/diesel blends were evaluated for a four stroke single cylinder diesel engine test rig. n-octanol and n-butanol were the alcohols considered. Experiments were conducted at different loads up to 4 kW and for alcohol contents from 10% to 40% by volume. The results indicated that the alcohol/diesel blends exhibited similar performance characteristics to that possessed by diesel. A slight drop in brake power was observed in all the blends compared to pure diesel. The brake thermal efficiency and brake specific fuel consumption increased in all alcohol blends at almost all the loads considered in the study. The emission analysis was also conducted using the AVL DI Test. The results revealed that CO and NO emissions decreased compared to pure diesel. However, HC emissions increased for n-butanol blends but they decreased in case of n-octanol blends. Results are a clear indication that these blends have an excellent potential and detailed investigations in real life conditions can lead to commercial usage.

Study of the influence of alcohols addition to gasoline on the distillation curve, and vapor pressure

Abstract The properties of gasoline change as a result of blending with an alcohol. The aim of this paper is to report new experimental data on distillation curve and Reid vapor pressure of pseudo-binary blends of a catalytic reforming gasoline with ethanol, i-propanol and n-butanol, respectively. Gasoline blend with ethanol was used as reference for discussing properties of isopropanol and respectively, n-butanol blends with gasoline. The main conclusion is that alcohol addition to gasoline affects the relevant characteristics of the blend that influence engine operation. Gasoline+i-propanol blends have intermediate behavior between gasoline+ethanol and gasoline+n-butanol blends.

An investigation on performance and combustion characteristics of pure n-butanol and a blend of n-butanol/ethanol as fuels in a spark ignition engine

The n-butanol, an alcohol with chemical characteristics similar to gasoline, was evaluated experimentally in a spark ignition (SI) engine and through two-zone computer modelling. To do so, n-butanol was burned as a pure fuel and compared to hydrous ethanol, and a blend of n-butanol/ethanol was compared to a blend of gasoline/ethanol in order to evaluate combustion characteristics and engine performance. Experimental results have shown that n-butanol performed worse than hydrous ethanol, especially due to its lower octane number, which at 13.5:1 compression ratio and 7 bar BMEP tested gave advantage to the second alcohol fuel properties due to knock limitation. At the same test conditions, n-butanol blend showed similar engine efficiency parameters, such as indicated power, when compared to the gasoline blend, indicating that n-butanol is a potential surrogate for gasoline when blended with ethanol. In order to evaluate auto-ignition occurrence, an ignition sweep was done at a 9.5:1 compression ratio and 6 bar BMEP, showing that pure n-butanol had its performance rather limited by knocking combustion and cyclic variability, while its blend with ethanol was able to avoid sporadic knock, achieving a desired performance with stable combustion.

Execution Analysis of Four Stroke C.I. Engine by Utilizing the N-Butanol Blend Diesel Fuel and Exhaust Emission

As the world population increases, the availability of fossil fuel decreases day-to-day, in this scenario we must deploy new alternative sources of energy and available sources can be used more efficiently. This study has discussed the diesel fuel mix with n-butanol in the four-stroke C. I. engine. This fuel contains n-butanol. Hence it controls atmospheric exhaust emission compared to take pure diesel fuel. N-butanol is the good cooling specialist by the mixing of n-butanol the Nitrous Oxide will be decreased. For this mixing, the brake thermal efficiency, exhaust emission and brake specific fuel consumption characteristics are investigated. The gas emissions of carbon monoxide, carbon dioxide (CO2), Nitrous Oxide and hydrocarbons (HC) are estimated by the utilization of AVL smoke meter. A mixture of Biodiesel and diesel was prepared in standard Butanol05, Butanol 10, Butanol 15, Butanol 20 and Butanol 30. Butanol05 means the mixture of 05% n-butanol and the remaining 95% volume of diesel. An experiment was performed with the pure diesel and Butanol 05, Butanol10, Butanol15, Butanol20 and Butanol30 fuel. The performance parameters evaluated included brake thermal efficiency for this blended fuel, exhaust emission characteristics and brake specific fuel consumption, Results was compared with Diesel mixing with n- butanol fuel and pure Diesel fuel. The experiment performed on single cylinder Compression Ignition Engine.

Performance and emission characteristics of diesel engine fueled with rice bran biodiesel and n-butanol

Due to the depletion of petroleum products and fatal emissions from the tailpipe of diesel engines it has become a need to seek for the alternative of petroleum products for long-term use. Currently, researchers and experts have come to the conclusion that biodiesel along with higher alcohols can be an appropriate substitute for this situation. Former investigations have presented that biodiesel and higher alcohol can help in improving the performance and depreciating harmful exhaust gases in a diesel engine. In the current investigation blends of diesel, rice bran biodiesel and n-butanol were prepared to check its effect on performance and emission characteristics of a diesel engine. Biodiesel was prepared by single stage alkaline transesterification process in this study and after that blends of diesel–biodiesel and diesel–biodiesel-n butanol were prepared as B10, B20, B10 nb10 and B20 nb20. Then these blends were tested in a single cylinder, small utility diesel engine with a rated power output of 3.73 kW to compare them with baseline diesel. Experimental investigation demonstrates that blends of rice bran biodiesel and n-butanol can be used as a fuel in a diesel engine without any change in the engine.

Experimental studies of a diesel engine run on biodiesel n-butanol blends

In this study, initially, n-butanol at low proportions viz. 5%, 10%, 15%, and 20% is blended with Karanja methyl ester (KME) respective proportions, and the blends are characterized. The blends are denoted as KBB5, KBB10, KBB15 and KBB20 where the numeric value followed by KBB indicates the percentage of n-butanol in the blends. The blends are used as test fuels in a single cylinder, four-stroke, direct injection (DI) diesel engine producing power of 4.4 kW at a constant speed of 1500 rpm. The combustion, performance and emission characteristics of the engine are evaluated and compared with the diesel engine operation. Further, an oxygenated additive: diethyl ether (DEE) in small quantities is added with the optimum blend to examine the reduction of unburnt hydrocarbon (UHC) emission from the engine when it is run with a biodiesel n-butanol blend. Among all the four KME n-butanol blends examined in this study, KBB15 exhibits good performance and less emissions. The results are presented in this paper.

Effect of n-butanol/diesel blends and piston bowl geometry on combustion and emission characteristics of CI engine.

The present study describes the experimental and numerical analysis of the combustion and emission characteristics of CI engine operated with diesel-butanol blends. Experiments were carried with neat diesel fuel (i.e., Bu00) and its blends of n-butanol, 10%, 20% and 30% by volume (Bu10, Bu20 and Bu30) at a constant speed and rated load. From the experimental results, it is observed that CO, NOx and smoke emissions decreased, whereas the unburned hydrocarbon (UBHC) emission increased with increasing butanol content, as compared to Bu00. From the experimental analysis, it is also observed that Bu20 blend gives higher brake thermal efficiency (BTE) and lower brake specific energy consumption (BSEC) as compared to Bu00, Bu10 and Bu30, but produces higher UBHC. In order to decrease the UBHC emission, different piston bowl geometries were analysed using simulation studies. The combustion and emission characteristics of the CI engine operating with Bu20 blend for three different piston bowl geometries viz., hemispherical combustion chamber (HCC), shallow combustion chamber (SCC) and toroidal combustion chamber (TCC), were studied using CONVERGE CFD code. The simulation model was validated with experimental results of the baseline engine configuration (HCC) for diesel fuel as well as Bu20 blend. The results showed that there is a significant reduction in UBHC and improvement of performance for SCC and TCC piston geometry compared to HCC piston geometry. However, a slight increment of NOx emissions was observed.

Experimental and chemical kinetic study of the impact of n-butanol blending on the gross engine performance of a CRDI engine

The effect of different fuel injection strategies for a CI internal combustion engine running on n-butanol/diesel blends is reported in this study. n-Butanol was blended in proportions of 5%, 10% and 20% (by vol.) and engine performance was compared with those obtained from commercially available diesel fuel. The effects of fuel injection pressure [FIP], start of injection [SOI] and split injection ratios were explored in this work. A single cylinder common rail direct injection engine running at a speed of 1050 ± 30 rpm was used for performance analysis. Initially, a baseline set of experiments were performed for all the fuel blends with the engine operating at 800 bars fuel injection pressure [FIP], 9° BTDC SOI, 3.48 BMEP and with 0% split injection. In-cylinder pressure, heat release rate, exhaust gas temperature and NOx emission were recorded for all the experiments. Additionally, for the base case, indicated gross engine performance parameters like BSFC and BTE were also determined. Subsequently, a parametric study of three different injection strategies was performed and variations in the indicated parameters and NOx emissions were thoroughly analysed. Significant reduction in NOx emission due to n-butanol blending, retarded start of injection and split injection were observed and reported as part of this work. A skeletal n-dodecane/n-butanol mechanism was used to investigate the causes for NOx emissions decrease due to the addition of n-butanol to diesel fuel. Qualitative insights gained from combustion kinetics simulations in an idealized homogeneous combustion model are discussed.

Chemical Kinetic Modeling Study on the Influence of n-Butanol Blending on the Combustion, Autoignition, and Knock Properties of Gasoline and Its Surrogate in a Spark-Ignition Engine

The ability of a mechanism describing the oxidation kinetics of toluene reference fuel (TRF)/n-butanol mixtures to predict the impact of n-butanol blending at 20% by volume on the autoignition and knock properties of gasoline has been investigated under conditions of a strongly supercharged spark-ignition (SI) engine. Simulations were performed using the LOGEengine code for stoichiometric fuel/air mixtures at intake temperature and pressure conditions of 320 K and 1.6 bar, respectively, for a range of spark timings. At the later spark timing of 6° crank angle (CA) before top dead center (BTDC), the predicted knock onsets for a gasoline surrogate (TRF) and the TRF/n-butanol blend are higher compared to the measurements, which is consistent with an earlier study of ignition delay times predicted in a rapid compression machine (RCM; Agbro, E.; Tomlin, A. S.; Lawes, M.; Park, S.; Sarathy, S. M. The influence of n-butanol blending on the ignition delay times of gasoline and its surrogate at high pressures. Fue...

Experimental Study on the Influence of n-Butanol Blending on the Combustion, Autoignition, and Knock Properties of Gasoline and Its Surrogate in a Spark-Ignition Engine

The impact of n-butanol blending on the combustion, autoignition and knock properties of gasoline has been investigated under supercharged spark ignition engine conditions for stoichiometric fuel/air mixtures at intake temperature and pressure conditions of 320 K and 1.6 bar, respectively, for a range of spark timings. A toluene reference fuel (TRF) surrogate for gasoline containing toluene, n-heptane and iso-octane has been tested experimentally in the Leeds University Ported Optical Engine (LUPOE) alongside a reference gasoline and their blends (20 % n-butanol and 80 % gasoline/TRF by volume). Although the gasoline/n-butanol blend displayed the highest burning rate, and consequently the highest peak pressures compared to gasoline, TRF and the TRF/n-butanol blend, it exhibited the least propensity to knock, indicating that addition of n-butanol provides an opportunity for enhancing the knock resistance of gasoline as well as improving engine efficiency via the use of higher compression ratios. The anti-knock enhancing quality of n-butanol on gasoline was however observed to weaken at later spark timings. Hence, whilst n-butanol has shown some promise based on the current study, its application as an octane enhancer for gasoline under real engine conditions may be somewhat limited at the studied blending ratio. As expected based on previous ignition delay studies, the TRF showed an earlier knocking boundary than the rest of the fuels, which may possibly be attributed to the absence of an oxygenate (ethanol or n-butanol) as present in the other fuels and a lower octane index. Overall, the TRF mixture gave a reasonable representation of the reference gasoline in terms of the produced knock onsets at the later spark timings for the pure fuels. However, on blending, the TRF did not reproduce the trend for the gasoline at later spark timings which can be linked to difficulties in capturing the temperature trends in ignition delays around the negative temperature coefficient region observed in previous work in a rapid compression machine (Agbro et al., Fuel, 2017, 187:211-219).

A comparative analysis of n-butanol/diesel and 1-pentanol/diesel blends in a compression ignition engine

The use of alcohols in diesel engines is an alternative way of reducing dependence on diesel fuel. Specifically, higher alcohols such as n-butanol (nB) and 1-pentanol (Pn), which consist of high carbons and can be produced from mainly non-edible sources, can directly be mixed with diesel fuel which in return provides significant promise from economic and environmental stand points. For this reason, the examination of the use of such high-carbon alcohols in diesel engines has become significantly important in recent years. In this work, six different binary (D-nB and D-Pn) fuel mixtures were obtained by mixing the diesel fuel with n-butanol and 1-pentanol at low and high mixing ratios (5%, 25% and 35% alcohol by volume) and basic fuel properties were examined. The test fuels were tested at four different loads (0, 3, 6 and 9 kW) at a constant engine speed (1800 rpm) in a direct injection diesel engine with diesel as the reference fuel. Fuel properties of the binary fuels were in compliance with the European Norm (EN590) and all of the fuels exhibit a steady phase without any indication of phase separation. Compared to diesel fuel’s engine characteristics, brake specific fuel consumption (BSFC) increased by 14.02% in binary blends, resulting in a 7.36% reduction in brake thermal efficiency (BTE). However, exhaust gas temperature (EGT) increased by an average of 47.55%. The addition of 1-pentanol to diesel had a significant impact on the decrease of oxides of nitrogen (NOx) emissions as an average decrease of 14.27% was observed. On the other hand, the higher latent heat of evaporation (LHE) of n-butanol and 1-pentanol had multiple disadvantageous outcomes such as a cooling effect in-cylinder, lower combustion efficiency and slightly higher carbon monoxide (CO) and hydrocarbon (HC) emissions as compared to diesel. The results indicated that the binary blends with 35% alcohol content happened to be a promising alternative for lower NOx emissions at the expense of increasing CO and HC emissions. Overall, it is concluded that n-butanol and 1-pentanol blends can be safely used in diesel engines without any engine modification or any additive.

Experimental and modelling study of the impacts of n-butanol blending on the auto-ignition behaviour of gasoline and its surrogate at low temperatures

The study investigates the impacts of n-butanol addition to a reference gasoline (RON 95, MON 86.6) and a gasoline surrogate on ignition delay times at various blending ratios (10%, 20%, 40% and 85% vol n-butanol) in a rapid compression machine, through experimental measurements and numerical modelling (T = 678–916 K, P = 2 MPa, stoichiometric conditions). The surrogate measurements are used to evaluate a recent chemical mechanism describing the combustion of the blends. The toluene reference fuel (TRF) surrogate showed adequate performance in replicating the ignition response of gasoline for all conditions tested, with closest agreement for the 85% blends. Some discrepancies existed within the negative temperature coefficient (NTC) region, suggesting that better matching of both MON and RON or additional surrogate components may be required. At low temperatures, increasing n-butanol concentration led to increases in ignition delay times. Here, n-butanol acted as an octane enhancer even at low concentrations, with marginal additional effects for blends above 40%. A brute force sensitivity analysis of the surrogate model suggested that the main reaction inhibiting ignition at low temperatures is H abstraction from the α-site of n-butanol, even for the 10% blend. At higher temperatures, the chain branching routes from H abstraction by OH from the γ-site of n-butanol, and from the α-site by HO2, become more dominant, promoting ignition. For the lower blends, the largest discrepancies between simulations and experiment were seen in the NTC region where a larger number of reactions contributed to the uncertainty in predicting τign. For the higher blends, the largest discrepancies were noted at low temperatures, indicating that uncertainties within the low temperature n-butanol chemistry need to be resolved. Accurate, temperature and pressure dependent reaction rates for site specific H abstraction by OH and HO2 for each of the fuel blend components are necessary to improve agreement between simulations and experimental data.

Study on combustion characteristics and particulate emissions of a common-rail diesel engine fueled with n-butanol and waste cooking oil blends

Biodiesel is a promising alternative fuel because of its renewability and extensive source of raw materials. Butanol can be blended in biodiesel to reduce the kinematic viscosity and promote the fuel atomization. In this respect, biodiesel was blended with 10% and 20% n-butanol, and the combustion characteristics and particulate emissions of the fuel blends were tested in a turbocharged, 6-cylinder, common rail diesel engine at a constant speed of 1400 rpm under seven engine loads. The experimental results show that under various engine loads, all of the butanol and biodiesel fuel blends provide faster combustion than diesel due to the higher oxygen content of n-butanol and the lower cetane number of butanol which results in stronger premixed combustion. The addition of butanol is beneficial to concentrating the heat release and thus shorten the combustion duration. With an increased proportion of butanol, soot emissions of butanol and biodiesel fuel blends decrease, the number concentration and volume concentration of ultrafine particles (UFPs) reduce noticeably. Meanwhile, the geometric mean diameters of UFPs decrease with an increase in butanol. With an increase of the engine loads, the number concentration peaks of UFPs gradually transfer from the size range of nucleation mode particles (NMPs) to the size range of accumulation mode particles (AMPs) due to the elevated combustion temperatures and high equivalence ratios. Moreover, biodiesel and fuel blends exhibit a higher percentage of NMPs as compared to diesel because of the fuel-bound oxygen, zero aromatics, and low sulfides.

Effect of gasoline/n-butanol blends on gaseous and particle emissions from an SI direct injection engine

N-butanol has shown potential as an alternative fuel to mitigate the energy crisis and reduce emissions. The emission and combustion characteristics of a spark ignition (SI) engine fed with gasoline/n-butanol blends under direct injection are studied in this paper. The experiments are conducted using different excess air ratios (λ) and n-butanol blending volume ratios (NBr). The results indicate that the indicated mean effective pressure (IMEP) and engine torque (Ttq) show small changes following n-butanol addition. The NOx and CO emissions decline continuously with increasing NBr. The n-butanol addition can help reduce HC emissions compared to neat gasoline when the NBr is below 40%; specifically, the HC emissions reach the lowest value at 20% NBr. As for particle emissions, the addition of n-butanol shows a very significant effect on the reduction of accumulation mode particle number, especially at rich-fuel mixture conditions, for which a decrease by about 52% is achieved. On the contrary, the nucleation mode particle number and peak particle diameter increase constantly with increasing NBr. Overall, the addition of 20% NBr to the blends reduces both particle and gaseous emissions. This work therefore presents a procedure to optimize the control of particle and gaseous emissions from gasoline/n-butanol blends, thus reducing the impact of the use of fossil fuel.

Effect of intake oxygen concentration on diesel–n-butanol blending combustion: An experimental and numerical study at low engine load

The blends of n-butanol and diesel are easy to achieve the premixed low-temperature combustion (PLTC) without larger exhaust gas recirculation (EGR) rate to maintain combustion stability and reduce emissions. Engine experiment and numerical modeling coupled with a new reduced mechanism were used to investigate both combustion and emission characteristics of D100 (pure diesel) and B30 (30% n-butanol and 70% diesel) under different intake oxygen concentrations (IOCs: 21%, 19%, 17%, and 15%). With the decrease in IOC, the maximum heat release rate (HRR) of D100 increased, while the maximum HRR of B30 first increased and then decreased. NOx emissions of two fuels differed slightly and both significantly decreased. Soot emission of D100 increased, while that of B30 first increased and then decreased. Moreover, under the same IOC, soot emission of B30 was less than that of D100. The chemical kinetic analysis shows that the addition of n-butanol consumed a certain amount of OH, slowed down the oxidation of n-heptane and toluene, and finally prolonged the ignition delay period. Additionally, decreasing in IOC suppressed the low-temperature O2-addition reactions of n-heptane and n-butanol to retard the reaction processes, prolonging the ignition delay. The numerical results show that as the decrease in IOC, the combustion rate decreased, the timings taken for the complete consumption of reactants and the formation of important intermediate products (CH2O, CO, H2O2, and OH) as well as soot precursors (C2H2, A1, and A4) were significantly delayed. Besides, the maximum mass fractions of CH2O, CO, and H2O2 increased, while the maximum OH mass fraction decreased. The formation of soot precursors exhibited similar trends, and reached the maximum mass fraction at an IOC of 17%. Specifically, the increase in soot emission of B30 was caused by the decrease in oxidation, while the decrease was mainly induced by the decrease in formation.

Cold- and warm-temperature emissions assessment of n-butanol blends in a Euro 6 vehicle

Alcohols produced from waste or lignocellulosic materials with advanced production techniques constitute a sustainable alternative as diesel fuel component. With respect to ethanol, the higher heating value of n-butanol together with its better miscibility with diesel fuel and lower hydrophilic character suggest that butanol is a better option as blending component for diesel fuels. A Euro 6 Nissan Qashqai 1.5 dCi light-duty vehicle was tested following the NEDC (New European Driving Cycle) on a chassis dynamometer located in a climatic chamber with different blends of diesel and n-butanol. Room temperatures were set at 24 °C and −7 °C. Butanol blends up to 16% (volume basis) showed benefits in particle number and particulate matter emissions upstream of the DPF at any ambient condition, this implying a reduction in the frequency of regeneration. Benefits in engine efficiency were observed at cold ambient temperature (−7 °C), just when the efficiency is poorest. Increases in NOx emissions were observed only at cold ambient temperature (−7 °C), while increases in CO and hydrocarbon emissions were found at any temperature. Blends with n-butanol content above 13% led to startability problems at cold ambient conditions. In general, including n-butanol as a blend component is beneficial for both performance and particulate emissions, but the blend concentration is limited by startability problems at very low ambient temperature.

Enhancement in the performance of a diesel engine fuelled with Pongamia methyl ester and n-butanol as oxygenated additive

ABSTRACTThe present paper investigates the performance and emission characteristics of a single-cylinder, four-stroke diesel engine fuelled with Pongamia methyl ester (PME) and n-butanol, at different loading conditions. Two blends of n-butanol–PME (10% and 20% n-butanol with PME on a volumetric basis) were prepared. The experimental results showed a significant improvement in the brake thermal efficiency of the engine with the blends and were found to increase with increasing percentage of n-butanol in the blends. The blended fuels also show lower emission such as carbon monoxide (CO), oxides of nitrogen (NOx) and smoke opacity. However, unburned hydrocarbon (HC) emission was found to be slightly increased. Thus, it is concluded that the biodiesel with 20% n-butanol blend showed better results with respect to efficiency and emissions point of view compared with biodiesel.

Experimental investigation on combustion, noise, vibrations, performance and emissions characteristics of diesel/n-butanol blends driven genset engine

Several emerging economies, including India, use diesel widely to produce electric power. This is accomplished through millions of small or medium sized generators driven by diesel engines. These engine-alternator combinations, or gensets, are extremely noisy, generate vibrations, and pollute air. There is a pressing need to find alternatives to diesel for such applications. Diesel-alcohol blends (diesohols) could be such alternatives. However, not much effort has been made till so far to evaluate their noise, vibration, emissions, performance, and combustion characteristics. This work fills such a gap by comprehensively investigating the efficacy of four different diesel/n-butanol blends. For this, a single-cylinder 4-stroke naturally aspirated direct injection diesel genset engine was operated at a fixed rpm and at six different load conditions. Detailed measurements of combustion noise, exhaust noise, total noise from the engine, engine vibrations, emissions (NOx, HC, CO, and smoke), engine pressure, and fuel consumption were made. Data from these measurements were used to establish inter-relationships between engine’s noise, vibration, emission, combustion and performance parameters. Linkages between these parameters, and key physical and chemical properties of test fuels were explored. Results show that noise and vibration characteristics of test diesohols are somewhat better especially at lesser loads. However, this trend reverses at higher loads. Analyses of results show strong correlation between combustion noise, rate of pressure rise, and vibration characteristics of test fuels. This work provides a detailed phenomenological explanation for such correlations in terms of fuel properties. Diesohols were also found to perform better for CO, NOx, and smoke emissions. However, the same may not be said for hydrocarbon emissions and engine efficiency particularly for diesohols with high n-butanol content. Finally, this work establishes that blends of n-butanol and diesel are viable alternatives for diesel for genset applications.

LTC (low-temperature combustion) analysis of PCCI (premixed charge compression ignition) with n-butanol and cotton seed biodiesel versus combustion and emissions characteristics of their binary mixtures

Abstract Direct injection (DI) of cotton seed biodiesel (CS100) with port fuel injection (PFI) of n-butanol was used for producing Premixed Controlled Compression Ignition (PCCI) to achieve low-temperature combustion (LTC) and obtain lower gaseous emissions in comparison to ULSD#2 (ultra-low sulfur diesel). PFI engine operation was compared to the combustion of binary mixtures of the same fuels reflecting the same weight ratio of high reactivity (CS100) and low reactivity (n-butanol) fuels. The supercharged engine was operated at constant speed and load with 20% exhaust gas recirculation (EGR). When compared to ULSD#2 reference, the ignition delay of 50% n-butanol and 50% CS100 binary mixture increased by 12% while the 50% n-butanol PFI with 50% CS100 DI led to a 17% decrease in ignition delay. Emissions of soot and nitrogen oxides were simultaneously improved using the PCCI strategy, reducing by 84% and 17%, respectively, given lower peak in-cylinder temperatures and increased oxygenation of the mixture. Carbon monoxide (CO) and unburned hydrocarbons (UHC) increased by several orders of magnitude as a downside of dual fuel injection; ringing intensity, however, improved, decreasing by 30% when using 50% n-butanol PFI in comparison to the ULSD#2 baseline given a smoother pressure gradients. Energy specific fuel consumption for CS50Bu50 (50% ULSD-50% n-butanol blend) increased by 4.5% compared to ULSD#2. The mechanical efficiencies and the coefficient of variation (COV) of IMEP were maintained at 70% and 2.5% respectively, during PCCI, indicating stable operation with renewable fuels.