Experimental investigation on the performance and emission characteristics of a diesel engine by varying the injection pressure and injection timing using mixed biodiesel

Biodiesel is a promising fuel for compression ignition engines instead of diesel fuel. Due to the depletion of diesel fuel, an alternative fuel can be used in an engine. The experiments were conducted on a four-stroke, single cylinder CI engine. In this present investigation, an attempt has been made to study the influence of injection pressure (IP) and injection timing (IT) on the performance and emission characteristics of diesel engines by using mixed biodiesel (Thevetia peruviana, Jatropha, Pongamia, and Azadirachta indica). The injection pressure is varied from 200 to 230 bar and the injection timing is varied from 23 to 29° bTDC at an increment of 10 bar and 2° bTDC, respectively, and the results were compared with diesel. From this study, the results showed that the brake thermal efficiency (BTE) was increased by 2.4% with an increase in injection pressure and 1.5% with an increase in the injection timing for the maximum load, but lesser than diesel. Furthermore, a reduction of 5.08% of brake specific fuel consumption (BSFC) has been noticed for the rise in IP and IT with loads but higher than diesel. The reduction was 34.17%, 53.85%, and 29.7% and 29.17%, 53.85%, and 21.95% of hydrocarbons (HC), carbon monoxide (CO), and smoke emissions, respectively, at 230 bar injection pressure and at 27° bTDC injection timing. Also, a significant increase in nitrogen oxides (NO_x) and carbon dioxide (CO₂) emissions at the maximum load was observed by increasing the injection pressure and injection timing.     

Investigation the effect of adding graphene oxide into diesel/higher alcohols blends on a diesel engine performance

ABSTRACT

This article aims to study the influence of the addition of graphene oxide nanoparticles (GO) to diesel/higher alcohols blends on the combustion, emission, and exergy parameters of a CI engine under various engine loads. The higher alcohols mainly n-butanol, n-heptanol, and n-octanol are blended with diesel at a volume fraction of 50%. Then, the 25 and 50 mg/L concentrations of GO are dispersed into diesel/higher alcohols blends using an ultrasonicator. The GO structures are examined using TEM, TGA, XRD and FTIR. The findings show that there is a reduction in p_max. and HRR when adding higher alcohols with diesel fuel. Regarding engine emission, there is a significant improvement in emissions formation with adding higher alcohols. The addition of GO into diesel/higher alcohols blends improves the brake thermal efficiency by 15%. Moreover, the p_max. and HRR are both enhanced by 4%. The CO, UHC and smoke formation are reduced considerably by 40%, 50 and 20%, respectively, while NO_x level is increased by 30% with adding GO. Finally, adding high percentages of n-butanol, n-heptanol, and n-octanol with diesel fuel with the presence of GO has the potential to achieve ultra-low CO, UHC, and smoke formation meanwhile keeping high thermal efficiency level.     

Investigation effect of hydrogen addition on the performance and exhaust emissions of Pongamia pinnata biodiesel fueled compression ignition engine

In the recent decades, the energy demand for transport and industrial sector has increased considerably. Fossil fuels which were the major fuel source for decades are no more sustainable. Biodiesel is an efficient alternative compared to depleting fossil fuels. The prospect of biodiesel as the best alternative fuel is a reliable source compared to depleting fossil fuels. Hydrogen is also considered as an attractive alternative fuel producing low emission with improved engine performance. This paper investigates the performance and emission characteristics of a single cylinder compression ignition engine using hydrogen as an inducted fuel and biodiesel, aka Pongamia pinnata as injected fuel. The experiments are conducted for different quantities of hydrogen induction through the intake manifold in order to improve the performance of the engine. The performance parameters such as brake thermal efficiency, brake specific fuel consumption, exhaust temperature and emission quantities like HC, NO_X, CO, CO₂ of biodiesel fueled CI engine with variable mass flow rate of hydrogen are investigated. The performances of biodiesel combined with hydrogen at varying mass flow rates are also compared. The 10 LPM hydrogen induction with biodiesel provided 0.33% increase of brake thermal efficiency compared with diesel and increase of 3.24% to biodiesel at 80% loading conditions. The emission of HC decreased by 13 ppm, CO decreased by 0.02% by volume and CO₂ decreased by 3.8% by volume for biodiesel with induction of hydrogen at 10 LPM to that of neat biodiesel for 80% load conditions.     

The effect of cerium oxide additive on the performance and emission characteristics of a CI engine operated with rice bran biodiesel and its blends

In this study, the rice bran oil (RBO) has been converted into methyl ester with an aid of transesterification reaction. Chemically, transesterification means conversion of triglyceride molecule or a complex fatty acid into alcohol and ester by removing the glycerin and neutralizing the free fatty acids. The B20 blend samples [80% diesel + 20% biodiesel] were prepared for each methyl ester obtained from RBO and then the cerium oxide (CeO₂) nanoparticles were added to the each B20 blend samples at a dosage of 50 ppm and 100 ppm with an aid of ultrasonicator. Moreover, in the absence of any engine modifications, the performance and emission characteristics of those blend samples have been investigated from the experimentally measured values such as density, viscosity, cloud point, pour point, and calorific value while the engine performance was also analyzed through the parameters like exhaust gas temperature (EGT), brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), exhaust emission of carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx). The experimental results reveal that the use of CeO₂ blended biodiesel in diesel engine has exhibited good improvement in performance characteristic and reduction in exhaust emissions.     

Performance of a diesel engine with water emulsified diesel prepared with optimized process parameters

An attempt has been made to produce stable water–diesel emulsion with optimal formulation and process parameters and to evaluate the performance and emission characteristics of diesel engine using this stable water–diesel emulsion. A total of 54 samples were prepared with varying water/diesel ratio, surfactant amount and stirring speed and water separation was recorded after 24 and 48 hr of emulsification. The recorded data were used in artificial neural network (ANN)-particle swarm optimization (PSO) technique to find the optimal parameters to produce water–diesel emulsion for engine testing. The predicted optimal parameters were found as 20% water to diesel ratio, 0.9% surfactant and 2200 rpm of stirrer for a water separation of 14.33% in one day with a variation of 6.54% against the actual value of water separation. Water–diesel emulsion fuel exhibited similar fuel properties as base fuel. The peak cylinder gas pressure, peak pressure rise rate and peak heat release rate for water–diesel were found higher as compared to diesel at medium to full engine loads. The improved air-fuel mixing in water–diesel emulsion enhanced brake thermal efficiency (BTE) of engine. The absorption of heat by water droplets present in water–diesel emulsion led to reduced exhaust gas temperature (EGT). With water–diesel emulsion fuel, the mean carbon monoxide (CO), unburned hydrocarbon and oxides of nitrogen (NO_x) emissions reduced by 8.80, 39.60, and 26.11%, respectively as compared to diesel.     

Effective application of ethanol in diesel engines

This work aimed to prove the effects of adding different proportions of ethanol with diesel (DE) and ethanol–water mixture with diesel (DEW) in a single-cylinder diesel engine on the performance, emissions, and combustion parameters. The blends were stabilized by tetra methyl ammonium bromide (TMAB) as the additive. The study was conducted at two operating conditions initially on a normal diesel engine and in the second case the engine piston, valves, and cylinder head coated with zirconia (ZrO₂) alumina (Al₂O₃). The results showed that the addition of 10% ethanol with diesel performed almost equivalent to neat diesel with 29.2% BTE and a 17.7% decrease in smoke and an 11.4% increase in NOx emission at peak load compared to that of the base fuel. Modified engines with thermal barrier coating (TBC) performed superior to normal engines with 4% and 5.5% increase in BTE, respectively, for DE- and DEW-type fuels with reduced exhaust emissions. A 5% addition of water with diesel–ethanol blends favors a higher proportion of ethanol to be employed in diesel engines.     

Ignition advancement study for optimized characteristics of a raw biogas operated spark ignition engine

In the current investigation, raw biogas obtained from rural sectors was used as the alternative to gasoline fuel in the spark ignition (SI) engine. The performance and efficiency are mainly dependent on the combustion phasing for which “ignition timing” is an effective tool in a SI engine. Hence, the objective of the present work is to understand the effect of “variable ignition timing” for a biogas-fueled SI engine. For this purpose, a single cylinder, 4-stroke, SI engine of rated power 4.5 kW was operated with raw biogas at a compression ratio (CR) of 10. By maintaining a speed of 1650 rpm, the engine was operated in wide open (WOT) and part throttle (PT) mode with an equivalence ratio of 0.81 and 0.83, respectively. It was observed that the biogas fueled SI engine was found to be operative only within the ignition advance (IA) range of 33–47° CA bTDC both in WOT and PT conditions. The results showed optimal brake power (BP), brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) are achieved at 45° CA bTDC. The average peak cylinder pressure, neat heat release rate (NHRR) and mean gas temperature (MGT) are also observed to be maximum while CO and HC emission at this point of IA were found to be minimum. Due to controlled and complete combustion, CO₂ and NO_x concentration in the exhaust emission were found to be higher at this point of ignition timing.     

Performance evaluation and emission characteristics of biodiesel-ignition enhancer blends propelled in a research diesel engine

This study details the effect of the Di-Methyl-Ether(DME) as a cetane improver on neat cashew nut shell biodiesel (CBD100) to assess the emission and performance engine characteristics. Four fuels, namely, diesel, biodiesel (Cashew nut shell Methyl Ester), a blend of CBD100-10% and 20% by volume of DME (CBD90DME10and CBD80DME20) are prepared and tested on a stationary research diesel engine. The experimental parameters for CBD80DME20 showed a 1.6% increase in thermal efficiency thereby reducing 4.1% of fuel consumption than the neat biodiesel at peak conditions. Experimental result exposed that 20% of DME reduces 3.4% CO, 4.2% HC and 8.8% NOx and 8.4% smoke emissions of CBD100. Based on the outcome of this work, it is clear that CBD80DME20 shall be employed as a substitute fuel for diesel engine.

Abbreviations: CI: Compression ignition; CBD100: Cashew nut shell Bio-diesel; DME: Di-methyl ether; CO: Carbon monoxide; BTE: Brake thermal efficiency; BSFC: Brake specific fuel consumption; CBD100: 100% Biodiesel; CBD90DME10: 90% biodiesel + 10% di-methyl-ether; CBD80DME20: 80% biodiesel + 20% di-methyl-ether; HC: Hydrocarbon; NO_x: Oxides of nitrogen.     

Effects of thermal barrier coating on the performance and combustion characteristics of a diesel engine fueled with biodiesel produced from waste frying cottonseed oil and ultra-low sulfur diesel

In this study, the top surfaces of piston and valves of a four-strokes and direct-injection diesel engine have been coated—with no change in the compression ratio—with a 100 μm of NiCrAl lining layer via plasma spray method and this layer has later been coated with main coating material with a mixture of 88% of ZrO₂, 4% of MgO and 8% of Al₂O₃ (400 μm). Then, after the engine-coating process, ultra-low sulfur diesel (ULSD) as base fuels and its blend with used frying cottonseed oil derived biodiesel in proportion of 20%, volumetrically, have been tested in the coated engine and data of combustion and performance characteristics on full load and at different speeds have been noted. The results, which were compared with those obtained by uncoated-engine operation, showed that thermal efficiency increased, and engine noise reduced. Cylinder gas pressure values obtained from the diesel engine which has been coated with thermal barriers have been found to be somewhat higher than those of the uncoated-engine. Also, maximum pressure values measured in both engines and under the same experimental conditions through the use of test fuel have been obtained after TDC. Moreover, heat release rate and heat release have occurred earlier in the coated-engine. NOx emissions were increased while CO and HC emissions were remained almost the same with a little bit decrease.     

对燃油征税的区域能源环境影响研究:以中国为例

控制汽柴油消费对中国的能源安全和环境保护有着重要意义.燃油税和碳税是中国近期两种主要的已经或可能施加于燃油的税收政策.以自回归分布滞后模型为核心,本研究构建了一个燃油税和碳税的区域能源环境影响评估模型.利用模型估计了我国的燃油需求价格弹性,测算了燃油需求响应,计算了在相同CO2减排目标下,提高汽油消费税、提高柴油消费税、引入碳税三种政策情景下各省份预计产生的节能效应、减排效应和税收效益.研究结果显示,在相同的CO2减排目标下,第一,在不同情景下,各省份节能程度差异均有限,但节能数量均体现出区域匹配性,燃油消费越多的省份,节能数量一般越多,且提高汽油消费税的全国节能总量最大;第二,在引入碳税情景下,各省份CO2减排比例差异最小;第三,在全国层面,三种政策情景中空气污染物(PM2.5和NOx和SO2)减排数量均为提高汽油消费税>引入碳税>提高柴油消费税,但在提高柴油消费税情景下,有4/5的省份预计PM2.5排放减少程度超过14%.除此之外,提高汽油消费税的税收收益最大.     

An experimental apparatus for testing biodiesels based on a CFR engine—setup and validation with different methyl ester blends

A cooperative fuel research (CFR) engine was modified and instrumented in order to control operating conditions and to measure engine parameters and in-cylinder pressure diagrams. Aiming at the comparison of different alternative fuels, an experimental procedure was defined, including cetane number (CN) evaluation and the definition of engine operating quantities in different working points, for fixed levels of compression ratio (CR) and injection advance. An investigation was made considering several blends of methyl-esters of rapeseed oil (RME) and of a mix of vegetable oils (VOME) with conventional diesel oil. The defined experimental procedure was applied to assess CN, engine brake thermal efficiency (bte) and exhaust emissions. Results show that the biodiesel content has a positive influence on soot emissions, with strong reduction, while thermal efficiency and NO_X emissions are negatively affected, which can be justified taking into account fuel properties and changes in combustion process. As observed outcomes are generally in line with those presented in literature, the facility proved to be a suitable tool for basic investigations on alternative fuels to be used in specific applications.     

Combustion features under different center of heat release of a diesel engine using dimethyl carbonate/diesel blend

Experiments were performed in a single cylinder common-rail diesel engine that adopts a low temperature premixed charge compression ignition (PCCI) mode. Combustion features of dimethyl carbonate (DMC)-diesel blends under various centers of heat release (COHRs) were revealed in details. With retarding of COHR, all the peaks of pressure and pressure rise rate and bulk gas temperature are postponed and declined in sequence. Normally, the crank angle of peak pressure is quite close to the COHR, while the peak of bulk gas temperature appears about 7°CA after COHR as a rule. The prolongation can be demonstrated at every stage of combustion such as q₁₀ and q₉₀ with the COHR being put backward. In addition, the heat release of diesel is completely slower than that of D10 fuel at various stages. Unfortunately, retarding of COHR implies a declining thermal efficiency of engines as well as a higher cyclic variation in general. Nevertheless, D10 blend has higher thermal efficiency than diesel thanks to high oxygen content of DMC and low boiling point that prompts better fuel atomization and complete combustion. Meanwhile, the cyclical variation of D10 is greater than diesel fuel owing to the low heat value, high latent heat of vaporization, and poor flammability of DMC. As a total, a comprehensive understanding of PCCI combustion features under different COHRs can be conducive to conducting effective management of combustion process and manipulating the subsequent emission performance to a favorable level.     

Combustion,emission, and phase stability features of a diesel engine fueled by Jatropha/ethanol blends and n-butanol as co-solvent

ABSTRACT

The main challenge of utilizing ethanol in diesel engines in blending mode is the phase separation issue. Therefore, an attempt has been performed to enhance the stability feature of ethanol/Jatropha biodiesel (JME) blends by using n-butanol as co-solvent. The 10% by volume of n-butanol is added to the mixtures of 10% and 20% ethanol and 70% and 80% JME, which is denoted as JME10Bu10E and JME10Bu20E, respectively. The phase stability of the evaluated fuels is examined employing visual approach and Thermogravimetric analysis. These methods confirm that there is no phase separation for more than 2 months under ambient conditions. Then, the combustion and emission features are investigated utilizing a diesel engine run with different loads and constant speed. The findings demonstrate that the p_max. and HRR are increased by adding ethanol. The ignition delay is extended with the addition of ethanol while the combustion period is almost the same. The bsfc is decreased by adding ethanol compared to JME fuel. The CO, UHC, and NO_x formations are reduced markedly by 40%, 40%, and 40%, respectively, with adding ethanol. Finally, using n-butanol and JME as co-solvents with ethanol supports the growth of renewable energy in the CI engine.     

Scleropyrum pentandrum (Dennst.) mabb—oil as a feedstock for biodiesel production—engine performance and emission studies

A feasibility study on utilization of non edible oil of Scleropyrum pentandrum was carried out to see its potential as a new source for biodiesel production. Nonedible oil seeds of Scleropyrum pentandrum have oil content of 55–60%. Transesterification of freshly extracted oil in the presence of anhydrous sodium hydroxide at a concentration 1% (w/v oil) and methanol-oil ratio of 40% (v/v oil) yields 90.8% methyl esters under conventional heating. Month old oil requires sulfuric acid pretreatment (esterification) before transesterification. The transesterified oil has a density 889–893 kg/m³; kinematic viscosity of 4.21–5.7 mm²/s; cetane index 46.03; pour point of ?15°C and gross calorific value of 40.135 MJ/kg and oxidative stability of 2.35 hours. The properties are well within the Indian, European and American standard limits recommended for biodiesel except the oxidation stability, which can be improved by adding antioxidant additives. The engine performance studies of B10 and B20 blends of Scleropyrum pentandrum biodiesel (SP biodiesel) with statistical inference confirmed that it can be used as a fuel in CI engines without any engine modifications. The engine exhaust emission analysis showed that the emission of hydrocarbons can be minimized by at least 15–20%, CO emission by 15%, smoke opacity by 10–12% and moderately lesser CO₂ and NOx emissions.     

Auto-adaptive Air Distribution and Structure Optimization of Ejector Burner for Biomass Alcohol Fuels

A plenty of studies on the utilization of biomass alcohol fuels have been conducted, but combustion efficiency and stability of this fuels still need to be improved. Based on biomass alcohol fuels (bio-methanol and bio-ethanol), this paper studied auto-adaptive air distribution characteristics and optimum structure parameters of an ejector burner by numerical simulation method. Also, an experiment was conducted to verify the numerical results. The results show that the mole air entrainment ratio (MAER) keeps almost constant when the ejector fuel nozzle exit locates at the segment between the ejector throat and the suction chamber entrance, but a bigger ratio α would lead to a higher MAER till the α is bigger than 8.5 for bio-methanol and 11.5 for bio-ethanol. The bio-ethanol fuel is more beneficial for air carrying role because of its big molecular weight. Operation pressure (P_w) has a little impact on MAER of the two fuels, but the rise of back pressure (P_b) would lead to rapid decrease of MAER for the two fuels. For the optimum structure burners, the MAER can be maintained at the value of theoretical complete combustion. Its changing rate is less than 2.3% for bio-methanol and 2.5% for bio-ethanol when the burner load changes from 30% to 120%, which is highly consistent with the experimental results. The optimum burner can distribute air supply automatically with the changing of burner load.     

Optimization of pretreatment conditions for enhanced sugar release

Present investigation was done to evaluate various algal genera found in water bodies of Varanasi city. The potential of any biomass for biofuels (bioalcohols, biohydrogen, etc.) production depends on the quantity of extractable sugar present in it. Acid (H₂SO₄) and alkali (NaOH) pretreatment were performed, and H₂SO₄ was chosen due to its nearly double yield as compared with alkaline pretreatment. Response surface methodology was utilized for the optimization of operating parameters such as treatment temperature, time, and acid concentration. Sugar yield up to 0.33 g/g of dry biomass was obtained using cyanobacterial biomass of Lyngbya limnetica, at 100°C, 59.19 min, and H₂SO₄ concentration of 1.63 M.     

Impact of various blends of Mimusops elengi methyl esters on performance and emission characteristics of a diesel engine

The basic objective of the research work was to study the effect of various blends of Mimusops elangi methyl ester (MEME) on engine performance, combustion, and emission characteristics of a single-cylinder direct-injection compression ignition engine, running at constant speed. The raw oil was extracted from Mimusops elangi seeds through mechanical crusher. The neat MEME was obtained through transesterification process and mixed with diesel in versatile proportions of 10% of MEME (10% MEME–90% Diesel), 20% of MEME(20% MEME–80% Diesel), 30% of MEME(30% MEME–70% Diesel), 40% of MEME(40% MEME–60% Diesel), and 100% MEME on a volume basis. Their properties were validated based on ASTM standards. Experimental investigation revealed that the 20% blend resulted in 4.18%, 5.12% more prominent performance characteristics of brake thermal efficiency, brake specific energy consumption, and superior emission diminution of 5.26% of HC, 16.6% of CO, 6.2% of smoke when compared with base diesel fuel, despite marginal penalty of 5.26% of carbon dioxide and 4.8% of oxides of nitrogen emission at full load condition. Characteristics of combustion parameters like pressure inside the cylinder and rate of the heat released were superior for 20% blend of MEME at the peak load condition.     

The use of petroleum coke as fuel in a 10 kWth chemical-looping combustor

Tests were made in a 10 kW_th chemical-looping combustor with a petroleum coke as the solid fuel and the oxygen carrier ilmenite, an iron titanium oxide. The fuel reactor is fluidized by steam and the oxygen carrier reacts with the volatiles released as well as the gasification intermediates CO and H₂. A constant fuel flow corresponding to a thermal power of 5.8 kW was introduced into the fuel reactor and a total of 11 h of operation was reached. The effects of particle circulation and carbon stripper operation on solid fuel conversion, conversion of gas from the fuel reactor and CO₂ capture were investigated. The actual CO₂ capture ranged between 60% and 75% while the solid fuel conversion was in the range of 66–78%. The low values of solid fuel conversion reflect loss of char due to low efficiency of the fuel reactor cyclone. The incomplete conversion of the gas from the fuel reactor is expressed as oxygen demand. The oxygen demand corresponds to the fraction of oxygen lacking to achieve full gas conversion and was typically 25%, due to presence of CH₄, CO and H₂ from the fuel reactor. Typical ratios of CH₄, CO and H₂ over the total gaseous carbon from the fuel reactor are respectively 5, 10 and 25%. Low loss of non-combustible fines from the system indicates very low attrition of the oxygen carrier.     

An investigation of engine and fuel system performance in a diesel engine operating on waste cooking oil

Waste cooking oil (WCO) was experimentally examined to determine whether it can be used as an alternative fuel in a 3-cylinder, 4-stroke, direct injection, 48 kW power tractor engine. The test engine was operated under full load conditions using diesel fuel and waste vegetable oil from the 2400 to 1100 rpm and performance values were recorded. Tests were performed in two stages to evaluate the effect of the waste oils on the engine life cycle. When the test engine was operated with diesel fuel and waste cooking oil; engine torque decreased between at ratio of 0.09 % and 3% according to the engine speed. While no significant difference occurs in the diesel fuel tests at the end of 100 hours of operation, an important reduction was observed in the engine torque of the WCO engine between 4.21% and 14.48% according to the engine speed, and an increase in average smoke opacity ratio was also observed. In accordance with the results obtained from the studies, it was determined that the engine performance values of waste cooking oil show similar properties with diesel fuel, but in long-term usage, performance losses increased. In the SEM analysis performed on the fuel system, there were dark deposits at the nozzle tip and stem. According to an EDX analysis at the nozzle tips, the detected elements point to engine oil ash in the combustion chamber and show coking products (C and O). The other elements (Na, S, Ca, P, Cl, and K) point to used WCO.     

Engine Performance and Emission Characteristics of Plastic Oil Produced from Waste Polyethylene and Its Blends with Diesel Fuel

The overall objective of this study was to explore the utility of waste plastics as a potential source of diesel fuel. An experimental study was conducted to evaluate the use of various blends of plastic oil produced from waste polyethylene (WPE) with diesel fuel (D). WPE was degraded thermally and catalytically using sodium aluminum silicate as a catalyst. The oil collected at optimum conditions (414°C–480°C range and 1 h reaction time) was fractionated at different temperatures and fuel properties of the fractions were measured. Plastic oil was blended with diesel fuel at the volumetric ratios of 5%, 10%, 15%, 20%, and 100%. Fuel properties of blends are found comparable with those of diesel fuel within the EN 590 Diesel Fuel standard and they can also be used as fuel in compression ignition engines without any modification. Engine performance and exhaust emission studies of 5% WPE-D (WPE5) blend were performed. Experimental results showed that carbon monoxide (CO) emission is decreased by 20.63%, carbon dioxide (CO₂) emission is increased by 3.34%, and oxides of nitrogen (NO_x) emission is increased by 9.17% with WPE-D (WPE5) blend compared to diesel fuel.