N-butanol Gasoline Research Articles

Performance optimization of gasoline engine fueled with ethanol/n-butanol/gasoline blends using response surface methodology

In this research work, the effect of adding oxygenates, ethanol and n-butanol, on the performance and emission characteristics of a multi-point fuel ignition (MPFI) engine is analyzed. The test engine was operated at 20 Nm load with speed between 1600 and 2800 rpm. The performance, combustion and emission characteristics of the engine were analyzed for different oxygenates (ethanol and n-butanol) and gasoline blends (EB5, EB10, EB15, EB20). A response surface methodology (RSM) model was developed using experimental data. The desirability function approach was used to predict the optimum values of the engine performance and emissions. The predicted optimum values of blend, load and speed are 20%, 20 Nm and 2702 rpm, respectively. For the optimum predicated values, the experiments found 20.9%, 0.46 kg/kWh, 0.0145%, 136.45 ppm, 4587 ppm for Brake thermal efficiency (BTE), Brake specific fuel consumption (BSFC), Carbon monoxide (CO), Hydrocarbon (HC) and Oxides of nitrogen (NOx), respectively. The study found less than 5% variation between the experimental and predicted results for the engine performance and emissions. The study also found that the ethanol/n-butanol/gasoline (EB–gasoline) blends produced better performance and emission results as compared to n-butanol–gasoline (B–gasoline) blends. The EB–gasoline blends displayed 1.8% higher efficiency as compared to B–gasoline blends.

A novel analysis of n-butanol–gasoline blends impact on spark ignition engine characteristics and lubricant oil degradation

ABSTRACT Butanol emerges as a potential biofuel for energizing modern automobiles. Its impact on engine performance and emission characteristics was investigated by many researchers. However, a research gap exists for its effect on lubricating oil deterioration. Therefore, n-butanol–gasoline blends were prepared with 6% and 12% by volume of alcohol (B6 and B12) and compared with pure gasoline (B0) in terms of engine performance, emissions, and lube oil condition. The engine performance along with exhaust gas temperature increased with an increasing ratio of butanol in the fuel blend. CO and HC emissions were the lowest in the case of B12 followed by B6 and B0. Furthermore, lubricating oil properties were determined to monitor its deterioration rate. The kinematic viscosity at 100°C and flash point temperature showed a minimum reduction in the case of B12, i.e., 22% and 16%, respectively, as compared to fresh oil. The highest concentration of wear elements in lube oil was detected for B12 fuel, which included Al (11 × 10−6), Fe (27 × 10−6), Cr (4 × 10−6), and Cu (13 × 10−6). Similarly, the additive counts for Ca, Mg, and Zn were found to be 1665 × 10−6, 7.3 × 10−6, and 730 × 10−6, respectively, in lubricating oil for B12. Therefore, advanced lubricating oil should be developed for alternative fuels to improve its lifecycle.

Comparisons of Using Ternary and Dual Gasoline–Alcohol Blends in Performance and Releases of SI Engines

Ternary mixed biofuels are receiving increased scientific attention, and recently, researchers proposed different biofuel mixtures under dissimilar engine conditions; each researcher argued that his/her proposed one is the next generation alternative. Accordingly, such ternary biofuel mixtures are extremely needed to be compared against each other under the same engine conditions to provide the best/most promising one(s) as coming fuel alternative(s) for SI engines. In the current study, comparing of using ternary bio-methanol–iso-butanol–gasoline (MiB), bio-ethanol–n-butanol–gasoline (EnB), and bio-methanol–n-butanol–gasoline (MnB) fuel mixtures in pollutant releases and behavior/performance of SI engines is carried out for the first time. The ternary alcohol–gasoline combined fuels were also compared against dual alcohol–gasoline fuel mixtures. In particular, MiB is compared against iso-butanol–gasoline (iB) and bio-methanol–gasoline (M) fuel mixtures; EnB is compared against n-butanol–gasoline (nB) and bio-ethanol–gasoline (E) fuel mixtures; MnB is compared against nB and M fuel mixtures. The comparisons of all combined fuels (ternary and dual bases) are carried out experimentally at the same biofuel mixtures rates and engine working conditions and also compared against pure fossil–gasoline. The results showed that the behavior/performance of MiB, MnB, and EnB are all lower than the pure fossil–gasoline, except for pressure inside cylinder for MiB. The highest behavior/performance among all ternary biofuel mixtures is introduced by MiB. Comparisons of pollutant releases (CO, UHC, and CO2) showed that MiB has the lowest levels, while MnB showed the highest levels, among all ternary mixtures. Comparisons to pure fossil–gasoline, the MiB and EnB ternary mixtures introduced lower, but MnB showed higher pollutant releases than the pure fossil–gasoline fuel.

Combustion and emission characteristics of n-butanol-gasoline blends in SI direct injection gasoline engine

N-butanol is a valuable renewable fuel that has been extensively studied. In this paper, the effect of n-butanol-gasoline blends on combustion and emissions performance of direct injection gasoline engine under urban conditions (throttle opening is 10% and 35%) is studied by using GT-Power simulation software. By comparing the several fuels, we find a fuel that is more suitable for the engine to operate in urban conditions. This is of great significance for reducing China's dependence on oil. The simulation results show that adding n-butanol into gasoline can significantly reduce the peak in-cylinder temperature (Tmax), improve the brake thermal efficiency (BTE) of the engine. It is advantageous for the engine to operate under urban conditions. By comparison, it is found that Bu40 is the most suitable fuel. When the throttle opening is 10%, high engine speed operation will reduce brake power (BP), brake torque (BT) and BTE, and increase CO emissions. In terms of emissions, n-butanol gasoline blends can reduce CO and NOx emissions, but HC emissions increase. Finally, the results show that n-butanol-gasoline blends can be used in SI direct injection gasoline engine instead of pure gasoline.

Investigation on Blending Effects of Gasoline Fuel with N-Butanol, DMF, and Ethanol on the Fuel Consumption and Harmful Emissions in a GDI Vehicle

The effects of three kinds of oxygenated fuel blends—i.e., ethanol-gasoline, n-butanol-gasoline, and 2,5-dimethylfuran (DMF)-gasoline-on fuel consumption, emissions, and acceleration performance were investigated in a passenger car with a chassis dynamometer. The engine mounted in the vehicle was a four-cylinder, four-stroke, turbocharging gasoline direct injection (GDI) engine with a displacement of 1.395 L. The test fuels include ethanol-gasoline, n-butanol-gasoline, and DMF-gasoline with four blending ratios of 20%, 50%, 75%, and 100%, and pure gasoline was also tested for comparison. The original contribution of this article is to systemically study the steady-state, transient-state, cold-start, and acceleration performance of the tested fuels under a wide range of blending ratios, especially at high blending ratios. It provides new insight and knowledge of the emission alleviation technique in terms of tailoring the biofuels in GDI turbocharged engines. The results of our works showed that operation with ethanol–gasoline, n-butanol–gasoline, and DMF–gasoline at high blending ratios could be realized in the GDI vehicle without any modification to its engine and the control system at the steady state. At steady-state operation, as compared with pure gasoline, the results indicated that blending n-butanol could reduce CO2, CO, total hydrocarbon (THC), and NOX emissions, which were also decreased by employing a higher blending ratio of n-butanol. However, a high fraction of n-butanol increased the volumetric fuel consumption, and so did the DMF–gasoline and ethanol–gasoline blends. A large fraction of DMF reduced THC emissions, but increased CO2 and NOX emissions. Blending n-butanol can improve the equivalent fuel consumption. Moreover, the particle number (PN) emissions were significantly decreased when using the high blending ratios of the three kinds of oxygenated fuels. According to the results of the New European Drive Cycle (NEDC) cycle, blending 20% of n-butanol with gasoline decreased CO2 emissions by 5.7% compared with pure gasoline and simultaneously reduced CO, THC, NOX emissions, while blending ethanol only reduced NOX emissions. PN and particulate matter (PM) emissions decreased significantly in all stages of the NEDC cycle with the oxygenated fuel blends; the highest reduction ratio in PN was 72.87% upon blending 20% ethanol at the NEDC cycle. The high proportion of n-butanol and DMF improved the acceleration performance of the vehicle.

Combustion performance of dual-injection using n-butanol direct-injection and gasoline port fuel-injection in a SI engine

In this study, combustion performance of dual-injection using n-butanol direct-injection (DI) and gasoline port fuel-injection (PFI) was evaluated. Dual-injection with various mass fraction of gasoline PFI and n-butanol DI were examined in a single cylinder SI engine operating at 1500 r/min, wide-open-throttle and stoichiometric air-fuel ratio (λ = 1). Indicated mean effective pressure (IMEP), knock behaviors, cylinder pressure and fuel consumption performance of dual-injection were compared with those of gasoline single-injection. At maximum brake torque (MBT) spark timings, dual-injections can produce higher engine IMEP when compared with gasoline PFI single-injection. Due to the increased engine IMEPs, dual-injections of 80% gasoline PFI-20% n-butanol DI (G80B20) and 50% gasoline PFI-50% n-butanol DI (G50B50) exhibited higher knock propensity and heavier knock intensity. When the mass fraction ratio of n-butanol DI reached to 80%, in-cylinder cooling effects of n-butanol vaporization dominated and led to a decrease of knock occurrence. Through in-cylinder pressure measurement, relatively high maximum combustion pressure with earlier crank angle were observed under dual-injection modes. Increase of the mass fraction of n-butanol DI, dual-injections resulted in higher fuel consumption rates. Nevertheless, comparisons of the indicated specific energy consumption rates of each injection mode indicated that n-butanol gasoline dual-injection had superior fuel conversion efficiencies.

An artificial neural network developed for predicting of performance and emissions of a spark ignition engine fueled with butanol–gasoline blends

The engine experiments require multiple tests that are hard, time-consuming, and high cost. Therefore, an artificial neural network model was developed in this study to successfully predict the engine performance and exhaust emissions when a port fuel injection spark ignition engine fueled with n-butanol–gasoline blends (0–60 vol.% n-butanol blended with gasoline referred as G100-B60) under various equivalence ratio. In the artificial neural network model, compression ratio, equivalence ratio, blend percentage, and engine load were used as the input parameters, while engine performance and emissions like brake thermal efficiency, brake-specific fuel consumption, carbon monoxide, unburned hydrocarbons, and nitrogen oxides were used as the output parameters. In comparison between experimental data and predicted results, a correlation coefficient ranging from 0.9929 to 0.9996 and a mean relative error ranging from 0.1943% to 9.9528% were obtained. It is indicated that the developed artificial neural network model was capable of predicting the combustion of n-butanol–gasoline blends due to a commendable accuracy.

Experimental investigation on the knocking combustion characteristics of n-butanol gasoline blends in a DISI engine

n-Butanol is a very competitive alternative biofuel for spark ignition (SI) engines given its many advantages. Current researches are mainly concentrated on the overall combustion and emissions performance concerning the feasibility of n-butanol gasoline blends in SI engines. In this work, focus was given on the knocking combustion characteristics of operation with pure n-butanol as well as a blend fuel with 20% volume content of n-butanol (Bu20), which was investigated experimentally in a direct-injection spark ignition (DISI) single cylinder engine. Operation condition is fixed at a constant engine speed of 1500r/min, using three throttle openings with stoichiometric air–fuel ratio. Spark timing was swept to achieve different knocking levels. The results of n-butanol and Bu20 were benchmarked against those obtained by the research octane number (RON) 92 commercial gasoline. Compared with the baseline fuel gasoline, neat n-butanol shows better anti-knock ability with more advanced knock limited spark timing, whereas slightly deteriorative knock resistance can be found for Bu20. It is hypothesized Bu20 has higher end gas temperature due to its higher brake mean effective pressure (BMEP) and faster burning rate compared with gasoline, which indicates the knock tendency depends not only on the fuel octane number, but also on the factors that affect the end gas thermodynamic state. The heavier knock propensity of Bu20 is furthermore confirmed by its more advanced knock onset and higher peak oscillation pressure. Results of fast fourier transform (FFT) indicate the knocking oscillation frequencies are mainly determined by the combustion chamber resonance modes. Statistics probability distribution and cumulative distribution are applied to evaluate the knock intensity variation for each fuel.

Experimental studies on simultaneous injection of ethanol–gasoline and n-butanol–gasoline in the intake port of a four stroke SI engine

Two separate injectors were used to simultaneously inject ethanol and gasoline in the intake port of a single cylinder SI engine. The relative amounts of the two fuels on mass basis and the spark timing were changed using a real time controller. Neat gasoline could be used till 35% throttle beyond which higher thermal efficiency and torque could be obtained by switching to 30% ethanol. This system can be used to provide sufficient margin for knock free operation. Efficiency and torque were better at a mass ratio of 1:1 (50% of ethanol and 50% of gasoline) due to faster combustion as a result of better mixture preparation as compared to conventional pre-blended injection of gasoline and ethanol. However, NO and HC were slightly elevated. This dual injection system can allow the use of ethanol only when needed while permitting stoichiometric operation even under high torque conditions by adjusting the proportion of ethanol. Ethanol–gasoline and n-butanol–gasoline were compared in terms of performance and emission with dual injection strategy. The amount of n-butanol has to be increased with increase in torque conditions for better performance and low emission. The benefit of using ethanol with gasoline is significant at high torque conditions.

Experimental study of dual n-butanol and iso-butanol additives on spark-ignition engine performance and emissions

The effect of using dual alcohols (n-butanol and iso-butanol) blended into gasoline fuel on spark-ignition (SI) engine performance and pollutant emissions is experimentally investigated. Three blend rates are applied (3, 7 and 10vol.% iso-butanol and n-butanol) as well as the neat gasoline as a base fuel; such dual blends are thought the first of their kind in internal combustion engines. The engine performance (brake power, BP, torque, Tq, volumetric efficiency, VE, pressure inside cylinder, P, and exhaust gas temperature, EGT) and pollutant emissions of CO, UHC (unburned hydrocarbons) and CO2 were examined at engine speeds of 2600–3400r/min for each blend rate and base fuel. In addition, engine performance and pollutant emissions of dual alcohols/gasoline blends were compared with those of single alcohol/gasoline blends, e.g., iso-butanol–gasoline and n-butanol–gasoline blends. Results demonstrate a higher performance and lower emissions when engine operated with dual alcohols/gasoline blends, compared to single ones. Dual alcohols with 10vol.% of n-butanol/iso-butanol blended in gasoline monitored the best performance and emissions among all the fuel blends (single or dual alcohols). However, results showed also a decrease in VE, BP, Tq, P and EGT when engine operated with the dual alcohols compared to base fuel. Nevertheless, performance of the dual alcohols can exceed those of the base fuel by increasing the blend rate value. Besides, dual alcohols burn cleaner than regular gasoline and produce slighter CO, CO2 and UHC pollutants by about 4.3%, 40% and 11%, respectively, compared to base fuel.

Experimental investigation on SI engine using gasoline and a hybrid iso-butanol/gasoline fuel

Experimental investigation on pollutant emissions and performance of SI engine fueled with gasoline and iso-butanol–gasoline blends is carried out. Engine was operated at speed range of 2600–3400r/min for each blend (3, 7 and 10vol.% iso-butanol) and neat gasoline. Results declare that the CO and UHC emissions of neat gasoline are higher than those of the blended fuels for speeds less than or equal to 2900r/min; however, for speeds higher than 2900r/min, we have an opposite impact where the blended fuels produce higher level of CO and UHC emissions than the gasoline fuel. The CO2 emission at using iso-butanol–gasoline blends is always lower than the neat gasoline at all speeds by up to 43%. The engine performance results demonstrate that using iso-butanol–gasoline blends in SI engine without any engine tuning lead to a drop in engine performance within all speed range. Without modifying the engine system, overall fuel combustion of iso-butanol–gasoline blends was quasi-complete. However, when engine system is optimized for blended fuels, iso-butanol has significant oxygen content and that can lead to a leaner combustion, which improves the completeness of combustion and therefore high performance and less emissions would be obtained. Finally, the performance and emissions of iso-butanol–gasoline blends are compared with those of n-butanol–gasoline blends at similar blended rates and engine working conditions. Such comparison is directed to evaluate the combustion dissimilarity of the two butanol isomers and also to emphasize which isomer is a superior fuel for SI engines.

Comparison of combustion characteristics of n-butanol/ethanol–gasoline blends in a HCCI engine

As a sustainable biofuel, n-butanol can be used in conventional spark ignition (SI) and compression ignition (CI) engines in order to reduce the dependence on fossil fuel. Homogeneous charge compression ignition (HCCI) is a novel combustion to improve the thermal efficiency of conventional SI engines at part loads. To understand the effect of alcohol structure on HCCI combustion under stoichiometric conditions highly diluted by exhaust gases, the combustion characteristics of n-butanol, ethanol and their blends with gasoline were investigated on a single cylinder port fuel injection gasoline engine with fixed intake/exhaust valve lifts at the same operating conditions in this study. The results show that autoignition timing for alcohol–gasoline blends is dependent on alcohol types and its concentration in the blend, engine speed and intake valve opening (IVO)/exhaust valve closing (EVC) timing. In the operating conditions with the residual gases more than 38% by mass in the mixture, alcohol–gasoline blends autoignite more easily than gasoline. Autoignition timing for n-butanol–gasoline blend is earlier than that for ethanol–gasoline blend with the same alcohol volume fraction at 1500rpm in most cases while the autoignition timings for the blends with alcohol are relatively close at 2000rpm at the same IVO/EVC timing. Combustion stability is improved with advanced EVC timing at a fixed IVO timing, which is benefit for the improvement in the thermal efficiency in the case of alcohol–gasoline blends. In addition, n-butanol–gasoline blends autoignite earlier than their ethanol–gasoline counterparts with identical oxygen mass content in the blend at the same IVO/EVC timings regardless of engine speeds. For alcohol–gasoline blends, the effect of IVO/EVC timing on the thermal efficiency of the HCCI engine is dependent on autoignition timing, fuel types and engine speeds. However, advanced autoignition timing for the blends with alcohol worsens the thermal efficiency of the HCCI engine in most cases.

Experimental study on emissions and performance of an internal combustion engine fueled with gasoline and gasoline/n-butanol blends

In this paper, exhaust emissions and engine performance have been experimentally studied for neat gasoline and gasoline/n-butanol blends in a wide range of working speeds (2600–3400r/min) without any tuning or modification on the gasoline engine systems. The experiment has the ability of evaluating performance and emission characteristics, such as break power, torque, in-cylinder pressure, volumetric efficiency, exhaust gas temperature and concentrations of CO2, CO and UHC. Results of the engine test indicated that using n-butanol–gasoline blended fuels slightly decrease the output torque, power, volumetric efficiency, exhaust gas temperature and in-cylinder pressure of the engine as a result of the leaning effect caused by the n-butanol addition; CO, CO2 and UHC emissions decrease dramatically for blended fuels compared to neat gasoline because of the improved combustion since n-butanol has extra oxygen, which allows partial reduction of the CO and UHC through formation of CO2. It was also noted that the exhaust emissions depend on the engine speed rather than the n-butanol contents.

Combustion and emission characteristics of a HCCI engine fuelled with n-butanol–gasoline blends

Biobutanol, i.e. n-butanol, is a promising alternative fuel or fuel blend to gasoline to reduce the consumption of fossil fuel and carbon dioxide emissions from spark ignition (SI) and homogeneous charge compression ignition (HCCI), also known as controlled autoignition (CAI), engines. In this work, investigation was conducted on a single cylinder port fuel injection four-stroke HCCI/CAI engine fuelled with gasoline (Bu0), the blend containing 30% n-butanol and 70% gasoline by volume (Bu30), and pure n-butanol (Bu100). The HCCI/CAI operation was achieved by the negative valve overlap strategy through variable exhaust and intake valve timing and lift devices. The results show that independent of engine speeds at a given exhaust valve closing (EVC) timing, the onset of the autoignition occurs earlier and combustion duration becomes shorter when an increasing amount of n-butanol is used in place of gasoline. The increase in the engine speed also advances the autoignition timing. However, indicated mean effective pressure (IMEP) decreases with increasing n-butanol in the blends and engine speeds. Furthermore, the effect of n-butanol on the emissions was studied, including oxides of nitrogen, formaldehyde, acetaldehyde, ethanol and aromatics in the engine exhaust.