Butanol-diesel Blends Research Articles

Performance, emission, and combustion characteristics of twin-cylinder common rail diesel engine fuelled with butanol-diesel blends.

Nitrogen oxides and smoke are the substantial emissions for the diesel engines. Fuels comprising high-level oxygen content can have low smoke emission due to better oxidation of soot. The objective of the paper is to assess the potential to employ oxygenated fuel, i.e., n-butanol and its blends with the neat diesel from 0 to 30% by volume. The experimental and computational fluid dynamic (CFD) simulation is carried out to estimate the performance, combustion, and exhaust emission characteristics of n-butanol-diesel blends for various injection timings (9°, 12°, 15°, and 18°) using modern twin-cylinder, four-stroke, common rail direct injection (CRDI) engine. Experimental results reveal the increase in brake thermal efficiency (BTE) by ~4.5, 6, and 8% for butanol-diesel blends of 10% (Bu10), 20% (Bu20), and 30% (Bu30), respectively, compared to neat diesel (Bu0). Maximum BTE for Bu0 is 38.4%, which is obtained at 12° BTDC; however, for Bu10, Bu20 and Bu30 are 40.19, 40.9, and 41.7%, which are obtained at 15° BTDC, respectively. Higher flame speed of n-butanol-diesel blends burn a large amount of fuel in the premixed phase, which improves the combustion as well as emission characteristics. CFD and experimental results are compared and validated for all fuel blends for in-cylinder pressure and nitrogen oxides (NOx), and found to be in good agreement. Both experimental and simulation results witnessed in reduction of smoke opacity, NOx, and carbon monoxide emissions with the increasing n-butanol percentage in diesel fuel.

Spray flame soot sampling and morphology analysis of butanol–diesel blends

To investigate soot formation, concentration and morphology differences affected by adding butanol to diesel, an experimental study was performed to compare in-flame soot morphology of diesel and butanol–diesel blends in a constant volume combustion chamber. Direct thermophoretic soot sampling was conducted in single-shot spray flame of pure diesel and 30% butanol-70% diesel blends. Soot samples were observed with a Transmission Electron Microscope, and soot morphology was analyzed and compared by subsequent image processing. Spray flame combustion process was recorded by a high-speed digital schlieren optical diagnostic system. Flame status variance of adding butanol was discussed and connected with soot formation and morphology differences. The result indicates that blending butanol could promote fuel atomization, optimize fuel-air mixing, delay ignition, accelerate combustion, and restrain soot formation. In butanol diesel blending spray flame, soot number and mass concentration are significantly smaller, and average size is smaller than that of pure diesel fuel, soot geometry and morphology are also changed.

Comparative evaluation of the effect of butanol–diesel and pentanol–diesel blends on carbonaceous particulate composition and particle number emissions from a diesel engine

This study was undertaken to comparatively evaluate the effects of blending butanol and pentanol with ultralow sulfur diesel (ULSD) at 10% and 20% by volume on engine performance, emissions of particulate mass and counts, and carbonaceous particulate components from a single cylinder, direct injection diesel engine. The engine was operated at a constant engine speed and at three engine loads. The results indicate a marginal change in the brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE). Compared to diesel fuel, both the blended fuels can effectively reduce the particulate mass and elemental carbon (EC) emissions, and also total counts of volatile and solid particles. Moreover, with the same proportion of butanol or pentanol in the blended fuels, the butanol–diesel blend shows a higher potential to inhibit EC formation and a higher emission reduction in solid and volatile particles in terms of their counts than that of the pentanol–diesel blend. However, both of the blended fuels show a slight decrease in organic carbon (OC) emissions, a significant increase in water-soluble organic carbon (WSOC) emissions and therefore high OC/EC and WSOC/OC ratios. In addition, the reduction of total particle number emissions with the addition of both butanol and pentanol is a result of a significant reduction in the number of particles larger than 50nm. However, the blended fuels show a slight increase in or no significant change in particles of less than 50nm while the number of particles with diameter less than 20nm increases for 20% butanol and pentanol blends at low engine load.

Numerical Study of the Formation of Soot Precursors during Low-Temperature Combustion of a n-Butanol–Diesel Blend

To study the soot precursor emission characteristics of a n-butanol–diesel blend during low-temperature combustion (LTC), a model of n-heptane, n-butanol, polycyclic aromatic hydrocarbons (PAHs), and toluene was chosen. Computational fluid dynamics (CFD) software was used to establish a three-dimenisonal (3D) numerical model and to couple it with the chemical kinetics mechanism. The factors studied on soot precursor production were n-butanol blending ratio, exhaust gas recirculation (EGR) rate, injection timing, and intake pressure. The results showed that the formation of four types of soot precursors benzene (A1), naphthalene (A2), phenanthrene (A3), and pyrene (A4) was delayed and the final amount of precursor produced decreased with increasing the n-butanol blending ratio. The delay in formation of these precursors and the reactions mostly occurred during the premixed combustion stage and with increasing the EGR rate. The final amount of A1 produced increased with the EGR rate; however, those of A2, A...

Effect of Fuel Injection Pressure & Fuel Supply Advance Angle on Characteristics of Butanol Diesel Blend Engine

The paper studied the effect of fuel injection pressure and fuel supply advance angle on characteristics of butanol diesel blend engine.First,the results shows that when the volume ratio of butanol diesel is constant ,the fuel consumption and HC emission are the least under 20°CA.With increase of fuel supply advance angle ,the exhaust smoke emission and CO emission decreased largely under high load, but NOX emission increased largely. When the fuel supply advance angle is constant ,with the increase of volume ratio of butanol diesel ,the fuel consumption increased gradually, the exhaust smoke emission decreased largely, HC emission increased clearly, CO emission decreased largely but NOX emission increased.Third,with increase of fuel injection pressure,the exhaust smoke emission decreased largely ,NOx emission changed a little ,CO and HC emission increased largely.

Comparative behavior of gasoline–diesel/butanol–diesel blends and injection strategy management on performance and emissions of a light duty diesel engine

Biodiesel or oxygenated fuel from renewable sources set a challenge to the engine technology to design relevant systems for keeping high efficiency and low environmental impact. The objective of this paper was to investigate the influence on combustion and emissions in a Euro 5 light duty diesel engine fueled with gasoline–diesel, butanol–diesel and commercial diesel fuels. Engine tests were carried out 2500 rpm and 0.8 MPa of brake mean effective pressure. The investigation was focused on the management of injection strategy for different combustion phasing under two oxygen concentrations at intake.The main results showed that the longer ignition delay and better volatility provided by the gasoline and butanol blends activated a premixed combustion mechanism for the single injection strategy, which helped to enhance the air/fuel mixing with benefits on smoke and NOx (nitrogen oxides) emissions. For the butanol-diesel blend, favorable effects on soot were also strengthened by the presence of O2 within the butanol molecule that plays a positive role on the reduction of local rich fuel regions and on soot formation and oxidation. The butanol–diesel blend gave lower UHC (unburned hydrocarbons) emissions than the diesel and gasoline–diesel blend because of the positive role played by the oxygen on the oxidation process.

Reducing emissions of persistent organic pollutants from a diesel engine by fueling with water-containing butanol diesel blends.

The manufacture of water-containing butanol diesel blends requires no excess dehydration and surfactant addition. Therefore, compared with the manufacture of conventional bio-alcohols, the energy consumption for the manufacture of water-containing butanol diesel blends is reduced, and the costs are lowered. In this study, we verified that using water-containing butanol diesel blends not only solves the tradeoff problem between nitrogen oxides (NOx) and particulate matter emissions from diesel engines, but it also reduces the emissions of persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons, polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, polychlorinated diphenyl ethers, polybrominated dibenzo-p-dioxins and dibenzofurans, polybrominated biphenyls and polybrominated diphenyl ethers. After using blends of B2 with 10% and 20% water-containing butanol, the POP emission factors were decreased by amounts in the range of 22.6%-42.3% and 38.0%-65.5% on a mass basis, as well as 18.7%-78.1% and 51.0%-84.9% on a toxicity basis. The addition of water-containing butanol introduced a lower content of aromatic compounds and most importantly, lead to more complete combustion, thus resulting in a great reduction in the POP emissions. Not only did the self-provided oxygen of butanol promote complete oxidation but also the water content in butanol diesel blends could cause a microexplosion mechanism, which provided a better turbulence and well-mixed environment for complete combustion.

Pollutant emissions from New European Driving Cycle with ethanol and butanol diesel blends

In this study, regulated gaseous emissions, smoke opacity and particle concentration derived from diesel fuel and two blends with alcohols (10% of ethanol and 16% of butanol) have been studied. A turbocharged, direct injection (DI), diesel engine equipped with common rail, injection system and EGR strategy was tested in test bench with road load simulation (RLS) during the New European Driving Cycle (NEDC). The tests were carried out always measuring upstream of the diesel particle filter (DPF). Results show slight increases in NOx and THC emissions with alcohol blends whereas CO emissions were reduced with these fuels. Particle mass (PM) was estimated from both the smoke opacity and particle size distributions. In both cases, important benefits are observed with alcohol blends.

Spray-combustion process characterization in a common rail diesel engine fuelled with butanol-diesel blends by conventional methods and optical diagnostics

The target of a sustainable mobility has led to investigate advanced combustion modes and fuels technologies. On the other side, the increasing global energy demand and the decreasing fossil-energy resources are enhancing the interest in the use of renewable alternative fuels for compression ignition engines with the target of near-zero emission levels. Although performance and emissions of alternative-fuel within light-duty diesel engines have been extensively investigated, results of fuel chemical composition impact on combustion by integrated optical methodologies are lacking. In order to meet this challenge, one of the main objectives of the research efforts is to characterize the combustion and species evolution. In this investigation, conventional tests and optical diagnostics were employed to enhance the comprehension of the combustion process and chemical markers in a common rail compression ignition engine powered by butanol-diesel blends. The investigation was focused on the effect of the injection strategy and blend composition on in-cylinder spray combustion and soot formation, through UV-visible digital imaging and natural emission spectroscopy. Experiments were performed in an optically accessible single cylinder high swirl compression ignition engine, equipped with a common rail multi-jets injection system. UV-visible emission spectroscopy was used to follow the evolution of the combustion process chemical markers. Spectral features of OH were identified and followed during the spray combustion process examining different pilot-main dwell timings. Soot spectral evidence in the visible wavelength range was correlated to soot engine out emissions. In this work, conventional and optical data related to diesel fuel blended with 40 % of n-butanol will be presented.

Spray-combustion process characterization in a common rail diesel engine fuelled with butanol-diesel blends by conventional methods and optical diagnostics

The target of a sustainable mobility has led to investigate advanced combustion modes and fuels technologies. On the other side, the increasing global energy demand and the decreasing fossil-energy resources are enhancing the interest in the use of renewable alternative fuels for compression ignition engines with the target of near-zero emission levels. Although performance and emissions of alternative-fuel within light-duty diesel engines have been extensively investigated, results of fuel chemical composition impact on combustion by integrated optical methodologies are lacking. In order to meet this challenge, one of the main objectives of the research efforts is to characterize the combustion and species evolution. In this investigation, conventional tests and optical diagnostics were employed to enhance the comprehension of the combustion process and chemical markers in a common rail compression ignition engine powered by butanol-diesel blends. The investigation was focused on the effect of the injection strategy and blend composition on in-cylinder spray combustion and soot formation, through UV-visible digital imaging and natural emission spectroscopy. Experiments were performed in an optically accessible single cylinder high swirl compression ignition engine, equipped with a common rail multi-jets injection system. UV-visible emission spectroscopy was used to follow the evolution of the combustion process chemical markers. Spectral features of OH were identified and followed during the spray combustion process examining different pilot-main dwell timings. Soot spectral evidence in the visible wavelength range was correlated to soot engine out emissions. In this work, conventional and optical data related to diesel fuel blended with 40 % of n-butanol will be presented.

Physicochemical and toxicological characteristics of particulate matter emitted from a non-road diesel engine: Comparative evaluation of biodiesel-diesel and butanol-diesel blends

Combustion experiments were conducted to evaluate the effects of using blends of ultralow sulfur diesel (ULSD) with biodiesel or n-butanol on physicochemical and toxicological characteristics of particulate emissions from a non-road diesel engine. The results indicated that compared to ULSD, both the blended fuels could effectively reduce the particulate mass and elemental carbon emissions, with butanol being more effective than biodiesel. The proportion of organic carbon and volatile organic compounds in particles increased for both blended fuels. However, biodiesel blended fuels showed lower total particle-phase polycyclic aromatic hydrocarbons (PAHs) emissions. The total number emissions of particles ≤560nm in diameter decreased gradually for the butanol blended fuels, but increased significantly for the biodiesel blended fuels. Both the blended fuels indicated lower soot ignition temperature and activation energy. All the particle extracts showed a decline in cell viability with the increased dose. However, the change in cell viability among test fuels is not statistically significant different with the exception of DB-4 (biodiesel–diesel blend containing 4% oxygen) used at 75% engine load.

Influence of butanol–diesel blends on particulate emissions of a non-road diesel engine

Ultralow sulfur diesel (ULSD) fuel was blended with 5%, 10%, 15% and 20% of butanol by volume. The effects of these blended fuels on physicochemical characteristics of particulate emissions and the cytotoxicity of particulate extracts from a single cylinder, direct injection stationary diesel engine were investigated with the engine working at a constant speed of 3000 revolutions per min (rpm) and at 25%, 50% and 75% of its maximum output power. The results indicated a decrease in particulate mass and elemental carbon (EC) emissions, while an increase in the proportion of organic carbon (OC) in the particles with an increase in butanol in the fuel. Compared to the ULSD, the total number concentrations of volatile and non-volatile particles were reduced significantly for blended fuels, whereas the number of particles with diameter less than 15nm increased for 15% and 20% butanol blends at low engine load. The increased total polycyclic aromatic hydrocarbons (PAHs) emissions, as well as their carcinogenic potency was also observed when the blends contained 15% and 20% butanol. In general, all the particle extracts showed a decline in cell viability with their increased dose and with the increased engine load while maintaining the same dose, based on the MTT assay.

On-Road Particulate Emission Characteristics of a Diesel Vehicle with Butanol-Diesel Blends

To study the applicability of alternative fuels, a TSI EEPS-3090 on-board vehicle particle emission test system is used on a diesel vehicle with a inline four-cylinder, electronic unit injectors, high pressure direct injection, turbocharging, 1.9L output volume engine, to investigate the on-road particulate emission characteristic burned with pure diesel, 10% and 20% by volume of n-butanol blend with pure diesel. Comparing the emission characteristics of different fuels, the study revealed that the butanol-diesel blend have a good effect of thinning the particle size without modifying and recalibrating the engine. In different types of roads and different VSP, the PN and PM of Bu10 and Bu20 are all less than that of D100; At same working conditions with the same kind of fuels, the particle size distribution are nearly the same; Compared with D100, Bu10 and Bu20, at different working conditions ,the particle size distribution are all bimodal, but Bu10 and Bu20 trend to be unimodal; At the same working conditions, the nucleation mode PN of Bu10 and Bu20 are obviously higher than that of D100, and the accumulation mode PN of Bu10 and Bu20 are obviously lower than that of D100; The peak of accumulation mode PN of Bu10 and Bu20 trend to be at smaller particle size.

Study on performance and emissions of a passenger-car diesel engine fueled with butanol–diesel blends

In this work, the commercially available diesel fuel (Bu00), butanol(20%)–diesel(80%) (by vol.) (Bu20), butanol(30%)–diesel(70%) (Bu30), and butanol(40%)–diesel (60%) (Bu40) fuels were tested. Experiments were conducted on a high-speed direct injection (DI) diesel engine for passenger-car application for varied loads at two representative engine speeds. The results showed that butanol–diesel blends slightly increased combustion pressure and accelerated burning rate. As fueled by the Bu40 blend, the maximum power output of the engine cannot be affected. Besides, butanol–diesel blends increased BSFC and brake thermal efficiency. Moreover, the effects of butanol addition on diesel engine exhaust emissions were varied with loads. Under low-load conditions, CO emissions obviously increased while NOx emissions decreased as butanol blending ratio increased. Under high-load conditions, on the contrary, CO emissions decreased but NOx emission increased. For the 40% butanol–diesel blend, in addition, HC emissions were higher than the neat diesel and lower percentage of butanol–diesel blends, especially at low-load. It is interesting that smoke decreased significantly at all conditions with the use of butanol–diesel blends, and the more butanol blending ratio the less smoke. Overall butanol is a potentially promising biofuel, which could be used conveniently up to high blending ratio with diesel fuel in diesel engines.

Butanol-Diesel Blends for Partially Premixed Combustion

Partially Premixed Combustion has shown the potential of high efficiency, emissions of nitrogen oxides (NOx) and soot below future emissions regulations, and acceptable acoustic noise. Low-octane-number gasoline fuels were shown to be most suitable for this concept, with the reactivity determining the possible load range. Other researchers have used several refinery streams, which might be produced by a refinery if they were required to do so without additional investment. Some of refinery streams are, however, not expected to be commercially available on the short term. For the present investigation, n-butanol (BuOH) has been selected as a blend component in diesel, and is used from 50 – 100%. The blends then have a reactivity range similar to the refinery streams, so single-cylinder engine tests for their emission and efficiency performance can also be used to determine their applicable load range. The current paper presents a summary of the performance of such BuOH-diesel blends with respect to emissions and efficiency in the Partially Premixed Combustion regime. Besides a presentation of the sensitivity to injection strategies, dilution levels and fuel pressure, emission performance is compared to upcoming legislated emission levels. The effect of the blend ratio on load ranges is shown and conventional diesel combustion benchmarks are used to show improvements in indicated efficiency. Butanol-diesel blends are shown to be a viable approach to partially premixed combustion, with its high soot reduction potential and stable operation. EURO VI emission levels can therefore be achieved, with moderate or slightly increased fuel pressure. Combustion efficiency is shown to be very reasonable over the whole load range, similar to that of conventional diesel combustion. Combined with an improved thermal efficiency a moderate butanol-diesel blend is shown to have an average gross indicated efficiency of 50% over the whole load range.

Finding Synergies in Fuels Properties for the Design of Renewable Fuels – Hydroxylated Biodiesel Effects on Butanol-Diesel Blends

This article describes the effects of hydroxylated biodiesel (castor oil methyl ester - COME) on the properties, combustion, and emissions of butanol-diesel blends used within compression ignition engines. The study was conducted to investigate the influence of COME as a means of increasing the butanol concentration in a stable butanol-diesel blend. Tests were compared with baseline experiments using rapeseed methyl esters (RME). A clear benefit in terms of the trade-off between NOX and soot emissions with respect to ULSD and biodiesel-diesel blends with the same oxygen content was obtained from the combination of biodiesel and butanol, while there was no penalty in regulated gaseous carbonaceous emissions. From the comparison between the biodiesel fuels used in this work, COME improved some of the properties (for example lubricity, density and viscosity) of butanol-diesel blends with respect to RME. The existence of hydroxyl group in COME also reduced further soot emissions and decreased soot activation energy.

Experimental study of n-butanol addition on performance and emissions with diesel low temperature combustion

Compared with ethanol or methanol, butanol has higher heating value and higher miscibility. Because of lower cetane number of butanol, butanol-diesel blends are more suitable for diesel low temperature combustion (LTC). In the paper, experimental study was carried out on a modified single cylinder heavy duty diesel engine to investigate the effects of n-butanol and EGR on diesel engine's combustion and emission characteristics. CA50 timing was fixed at 8 °CA ATDC and two different volume fractions (20% and 40%) of n-butanol were blended into diesel fuel. The results showed that with the increase of n-butanol fraction, ignition delay prolonged, (dp/dφ)max increased and indicated thermal efficiency (ITE) had a slight increase. Fuel properties had little effects on NOx emission, but NO proportion decreased and NO2 proportion increased with higher n-butanol fraction. With n-butanol addition, CO and THC (total hydrocarbon) emissions decreased at higher EGR levels, soot emissions reduced greatly and soot-bump was almost eliminated. With the increase of EGR rate, CH4 proportion increased, but n-butanol addition could decrease CH4 proportion.

A Study on a Passenger Car Diesel Engine Fueled with Butanol-Diesel Blend under Typical Operating Condition

The effects of butanol-diesel blending ratio, injecting timing and pilot injection quantity on combustion and emissions were experimentally investigated for a passenger car diesel engine. The results showed that under the typical operating condition of 2000r/min engine speed and 0.2MPa BMEP engine load, the engine’s combustion phase retarded, the peak combustion pressure and maximum in-cylinder mean temperature decreasing with the delay of the main injection timing using both the neat diesel and diesel-butanol blends. And the engine smoke level increased, while the NOx and CO emissions decreased. However, at the same main injection timing, with the increase of the butanol in the blends, the ignition delay of the combustion prolonged, the burn rate and brake specific fuel consumption increased, NOx and soot emissions decreased, and HC and CO emissions increased, while the peak in-cylinder pressure was slightly influenced. The results of this study indicate that the selection of the butanol-diesel blend ratio and injection timing should consider the engineering balances among the engine’s fuel economy and emissions.

Pollutant emissions from engine starting with ethanol and butanol diesel blends

The starting is a special transient process of engine operation, which is included in the New European Driving Cycle of light duty vehicles (NEDC). This is a critical operation mode of diesel engines with respect to pollutant emissions and to stability of the combustion process. In this work, a turbocharged, direct injection (DI), diesel engine equipped with common rail injection system and EGR strategy was tested during the starting. The engine was tested at relatively cold and warm start. Pollutant emissions (HC, NOx, smoke opacity and particle size distributions), in-cylinder pressure and operating parameters such as rotation speed, relative fuel–air ratio and EGR valve position were registered during the tests. The engine was fueled with a pure low sulfur diesel fuel, and blended with ethanol and butanol. Fuel blends were prepared with the same oxygen content (~3.3% in mass). The results show that alcohol diesel blends lead to a positive effect on the reduction in the smoke opacity and particle concentration during warm engine start with similar nitrogen oxide (NOx) emissions. At cold start, blends tested produced combustion instabilities. This fact, jointly with inefficient operation of the diesel oxidation catalyst, produced an increase of all regulated pollutant emissions.

The Effects of EGR and Injection Timing on the Engine Combustion and Emission Performances Fueled by Butanol-Diesel Blends

The Effects of EGR and Injection Timing on the Engine Combustion and Emission Performances Fueled by Butanol-Diesel Blends