高原地区柴油机燃用生物柴油混合燃料排放特性研究

在高原环境（81kPa）下,对4100QBZL型柴油机燃用不同配比生物柴油混合燃料后的排放特性进行了实验研究。实验结果表明：与燃用柴油相比,各工况下,HC、CO和碳烟的排放均有不同程度的降低（分别平均下降4．5％～38．4％、15．4％～43．9％和12．5％～65．5％）,高负荷低转速工况下效果尤为明显;NOx的排放也得到明显改善,只有纯生物柴油的NO。排放较柴油上升了0％～2．1％,其他指标均下降（平均下降4．4％～4．9％）。综合考虑,燃用掺混比为30％以内的生物柴油混合燃料,能同时有效地降低HC、CO、NOx和碳烟的排放。     

不同大气压力和生物柴油/柴油掺混比对柴油机噪声的影响

使用大气模拟试验台进行了直喷式柴油机在高原环境不同大气压下燃用不同体积掺混比生物柴油/柴油混合燃料的噪声测量对比试验研究。结果表明：噪声声功率随着大气压力和生物柴油掺混比的增加而减小;怠速工况时,在101kPa和81kPa大气压下分别燃用掺混比为70%和80%的混合燃料噪声值最小;在630～2000Hz噪声主要贡献频带上,各个测试点燃用B100油时声压级较B0油小;在高原环境下使用生物柴油可有效地降低柴油机整机噪声。     

Investigation on emission characteristics of alcohol biodiesel blended diesel engine

The present study analyzes the emission pattern of Decanol combined Jatropha biodiesel (JBD100) fueled diesel engine and compared with conventional diesel fuel (D100). Experiments were conducted in a single-cylinder, 4-stroke naturally aspirated diesel engine with an eddy current dynamometer at a constant speed of 1800 rpm. Modified fuel was prepared using a mechanical agitator, in which the Decanol concentration was varied from 10 to 20% to JBD100. The physicochemical properties of Decanol combined biodiesel are within ASTM limits. JBD100 promotes a lower level of carbon monoxide (CO) hydrocarbon (HC), and smoke emissions with notable increases in NO_x and carbon dioxide (CO₂) emissions. An inclusion of 20% Decanol in JBD100 reduces the NO_x, Smoke, CO, and HC emission by 7.4%, 4.4%, 5.7%, and 5.9%, respectively, under full brake power.     

Numerical simulation of biodiesel fuel combustion and emission characteristics in a direct injection diesel engine

The effect of the physical and chemical properties of biodiesel fuels on the combustion process and pollutants formation in Direct Injection (DI) engine are investigated numerically by using multi-dimensional Computational Fluid Dynamics (CFD) simulation. In the current study, methyl butanoate (MB) and n-heptane are used as the surrogates for the biodiesel fuel and the conventional diesel fuel. Detailed kinetic chemical mechanisms for MB and n-heptane are implemented to simulate the combustion process. It is shown that the differences in the chemical properties between the biodiesel fuel and the diesel fuel affect the whole combustion process more significantly than the differences in the physical properties. While the variations of both the chemical and the physical properties between the biodiesel and diesel fuel influence the soot formation at the equivalent level, the variations in the chemical properties play a crucial role in the NO_x emissions formation.     

The experimental study on the performance,combustion and emission characteristics of a diesel engine using diesel – biodiesel – diethyl ether blends

ABSTRACT

In the present research work, the experimental analysis has been executed to investigate the influence of diethyl ether as an oxygenated additive to the diesel-biodiesel blend on the performance, combustion and emission characteristics of a diesel engine. The biodiesel (Frying oil methyl ester) was prepared by the transesterification process, and the biodiesel was added (40% by volume) to the diesel fuel to prepare the diesel-biodiesel blend (D60FME40). The diethyl ether was added to the diesel-biodiesel blends D60FM35 (diesel 60% + biodiesel 35% by volume) and D60FM30 (diesel 60% + biodiesel 30% by volume) with suitable volume proportions of 5% and 10% respectively to form diesel-biodiesel-diethyl ether blends ((D60FM35DEE5) & (D60FM30DEE10)). Initially, the test was conducted with diesel fuel to obtain the baseline reference reading. Then, the reading was compared with results taken from the engine using a diesel-biodiesel blend (D60FME40) and diethyl ether blends (D60FM35DEE5) & (D60FM30DEE10). The results reveal that the maximum brake thermal efficiency was obtained with diesel fuel and it was higher than the diesel-biodiesel blend and diethyl ether blends. The peak in-cylinder gas pressure and heat release rate in the premixed stage was less for the diesel-biodiesel blend, but it was increased with the addition of diethyl ether to the blend. The diesel-biodiesel-diethyl ether blends show less carbon monoxide and hydrocarbon emissions except for NO_X emission as compared to the diesel and diesel-biodiesel blend, especially at the engine rated power.     

Performance of multi-cylinder diesel engine fueled with mahua biodiesel using Selective Catalytic Reduction (SCR) technique

India is mainly an agricultural country. For irrigation, the farmers are primarily dependent on diesel engines which run on immaculate diesel. In order to reduce the consumption of diesel, oxygenated fuel additives seem to be a good proposition. In this connection, biodiesel is one of the best choices and this study is an attempt in that direction. Of the various non-edible vegetable oils available for making biodiesel, Mahua oil (Madhuca Indica) is preferred since it is widely available across the country. The problem with biodiesel is the higher emission of oxides of nitrogen (NO_x). NO_x emissions can be controlled with Ad-Blue (Urea) solution. Fortunately, for the irrigation sector, it may be considered as a blessing in disguise since, Urea which is used to control the NOx emissions is used as a fertilizer. In this work an experimental study has been carried out to assess the suitability of selective catalytic reduction (SCR) technique in reducing NO_x. To arrive at accurate results, property characterization has been carried out for various blends. Tests were conducted on a multi-cylinder water cooled diesel engine at 2400 rpm. For loading an eddy current dynamometer was used. The injection nozzle opening pressure (NOP) was set to 220 bar with constant static injection timing (SIT) of 18° before top dead center (bTDC). This study presents the results at full load, employing SCR technique. The results were compared with conventional engine results under same operating condition where no reduction technique was employed. It was found that there was a significant reduction in NO_x (around 3.91%) when the engine was operated with 25% biodiesel, thereby saving 25% diesel. This study establishes that SCR technique with 25% biodiesel addition as a viable option without any modification in the engine and without any compromise on the engine performance. Therefore, this option can be considered as sustainable one in agricultural operation.     

Experimental investigations on combustion, performance and emissions characteristics of neat karanji biodiesel and its methanol blend in a diesel engine

The increased focus on alternative fuels research in the recent years are mainly driven by escalating crude oil prices, stringent emission norms and the concern on clean environment. The processed form of vegetable oil (biodiesel) has emerged as a potential substitute for diesel fuel on account of its renewable source and lesser emissions. The experimental work reported here has been carried out on a turbocharged, direct injection, multi-cylinder truck diesel engine fitted with mechanical distributor type fuel injection pump using biodiesel-methanol blend and neat karanji oil derived biodiesel under constant speed and varying load conditions without altering injection timings. The results of the experimental investigation indicate that the ignition delay for biodiesel-methanol blend is slightly higher as compared to neat biodiesel and the maximum increase is limited to 1 deg. CA. The maximum rate of pressure rise follow a trend of the ignition delay variations at these operating conditions. However, the peak cylinder pressure and peak energy release rate decreases for biodiesel-methanol blend. In general, a delayed start of combustion and lower combustion duration are observed for biodiesel-methanol blend compared to neat biodiesel fuel. A maximum thermal efficiency increase of 4.2% due to 10% methanol addition in the biodiesel is seen at 80% load and 16.67 s⁻¹ engine speed. The unburnt hydrocarbon and carbon monoxide emissions are slightly higher for the methanol blend compared to neat biodiesel at low load conditions whereas at higher load conditions unburnt hydrocarbon emissions are comparable for the two fuels and carbon monoxide emissions decrease significantly for the methanol blend. A significant reduction in nitric oxide and smoke emissions are observed with the biodiesel-methanol blend investigated.     

Direct injection diesel engine performance,emission, and combustion characteristics using diesel fuel,nonedible honne oil methyl ester,and blends with diesel fuel

Honne oil methyl ester (HOME) is produced from a nonedible vegetable oil, namely, honne oil, available abundantly in India. It has remained as an untapped new possible source of alternative fuel that can be used for diesel engines. The present research is aimed at investigating experimentally the performance, exhaust emission, and combustion characteristics of a direct injection diesel engine (single cylinder, water cooled) typically used in agricultural sector over the entire load range when fuelled with HOME and diesel fuel blends, HM20 (20% HOME + 80% diesel fuel)–HM100. The properties of these blends are found to be comparable with diesel fuel conforming to the American and European standards. The combustion parameters of HM20 are found to be slightly better than neat diesel (ND). For other blend ratios, these combustion parameters deviated compared with ND. The performance (brake thermal efficiency (BTE), brake‐specific fuel consumption, and exhaust gas temperature) of HM20 is better than ND. For other blend ratios, BTE is inferior compared with ND. The emissions (CO and SO) of HM20–HM100, throughout the entire load range, are dropped significantly compared with ND. Unburned hydrocarbon emissions of HM20–HM40, throughout the entire load range, is slightly decreased, whereas for other blend ratios, it is increased compared with ND. NO_x emissions of HM20, throughout the entire load range, is slightly increased, whereas for other blend ratios, it is slightly decreased. The reductions in exhaust emissions together with increase in BTE made the blend HM20 a suitable alternative fuel for diesel fuel and thus could help in controlling air pollution. Copyright © 2011 John Wiley & Sons, Ltd.     

Effect of nanoparticle on emission and performance characteristics of a diesel engine fueled with cashew nut shell biodiesel

High-rise in the air pollution levels due to combustion of the fossil fuel gives us the opportunity to discover environmentally friendly and clean fuels for the engines. Biodiesel originated from cashew nut shell oil through transesterification process can be blended or used as a neat fuel in unmodified engines. This work investigates the effect of alumina nanoparticles on emission and performance characteristics of cashew nut shell biodiesel. Neat cashew nut shell biodiesel prepared by conventional transesterification is termed as BD100 and biodiesel prepared by modified transesterification with the addition of alumina nanoparticles is termed as BD100A. Experimental results on unmodified diesel engine revealed that emission parameters such as CO, HC, NOx, and smoke were decreased by 5.3%, 7.4%, 10.23%, and 16.1% for BD100% and 8.8%, 10.1%, 12.4%, and 18.4% for B100A, respectively, compared to diesel fuel. At full load conditions, compared to diesel fuel, the BTE dropped by 1.1% and 2.3%, whereas the BSFC increased by 3.8% and 5.1% for B100A and B100 correspondingly.     

Combustion characteristics of CI engine fueled with WCO biodiesel/diesel blends at different compression ratios and EGR

The present study investigated the effect of compression ratio (CR) with the use of exhaust gas recirculation (EGR) technology on the performance of combustion characteristics at different CRs and engine loads; the brake thermal efficiency (BTE), specific fuel consumption (SFC), volumetric efficiency (VOL.EFF), exhaust gas temperature, carbon dioxide emission (CO₂), hydrocarbons (HC), nitrogen oxides (NOx), and oxygen content (O₂). The single-cylinder, four-stroke compression ignition engine was run on a mixture of diesel and biodiesel prepared from Iraqi waste cooking oil at (B0, B10, B20, and B30). A comparison has been achieved for these combustion characteristics at different blends, load, and CRs (14.5, 15.5, and 16.5) at 1500 rpm constant engine speed. The transesterification process is used to produce biodiesel and ASTM standards have been used to determine the physical and chemical properties of biodiesel and compare them to net diesel fuel. The preliminary conducting tests indicated that engine performance and emissions improved with the B20 mixture. Experimental test results showed an increase in BTE when CR increased by 17% and SFC increased by 23%. It also found a higher VOL.EFF by 6% at higher pressure ratios. A continuous decrease in BTE values and an increase in SFC were sustained when the percentage of biodiesel in the mixture was increased. Emissions of carbon dioxide, HC, and NOx increased by 12%, 50%, and 40%, respectively, as CR reached high values. NOx increased with the addition of biodiesel to 35%, which necessitated the use of EGR technology at rates of 5% and 10%. The results indicated that the best results were obtained in the case of running the engine with a mixing ratio of B20 with the addition of 10% EGR, NOx decreased by 47% against a slight increase in other emissions.     

Combustion characteristics of a direct-injection diesel engine fueled with Fischer-Tropsch diesel

Fischer-Tropsch (F-T) diesel fuel is characterized by a high cetane number, a near-zero sulphur content and a very low aromatic level. On the basis of the recorded incylinder pressures and injector needle lifts, the combustion characteristics of an unmodified single-cylinder direct-injection diesel engine operating on F-T diesel fuel are analyzed and compared with those of conventional diesel fuel operation. The results show that F-T diesel fuel exhibits a slightly longer injection delay and injection duration, an average of 18.7% shorter ignition delay, and a comparable total combustion duration when compared to those of conventional diesel fuel. Meanwhile, F-T diesel fuel displays an average of 26.8% lower peak value of premixed burning rate and a higher peak value of diffusive burning rate. In addition, the F-T diesel engine has a slightly lower peak combustion pressure, a far lower rate of pressure rise, and a lower mechanical load and combustion noise than the conventional diesel engine. The brake specific fuel consumption is lower and the effective thermal efficiency is higher for F-T diesel fuel operation. Translated from Journal of Xi’an Jiaotong University, 2006, 40(1): 5–9 [译自: 西安交通大学学报]     

Performance characteristics of a low heat rejection diesel engine operating with biodiesel

Vegetable oils are a promising alternative among the different diesel fuel alternatives. However, the high viscosity, poor volatility and cold flow characteristics of vegetable oils can cause some problems such as injector coking, severe engine deposits, filter gumming, piston ring sticking and thickening of lubrication oil from long-term use in diesel engines. These problems can be eliminated or minimized by transesterification of the vegetable oils to form monoesters. These monoesters are known as biodiesel. The important advantages of biodiesel are lower exhaust gas emissions and its biodegradability and renewability compared with petroleum-based diesel fuel. Although the transesterification improves the fuel properties of vegetable oil, the viscosity and volatility of biodiesel are still worse than that of petroleum diesel fuel. The energy of the biodiesel can be released more efficiently with the concept of low heat rejection (LHR) engine. The aim of this study is to apply LHR engine for improving engine performance when biodiesel is used as an alternative fuel. For this purpose, a turbocharged direct injection (DI) diesel engine was converted to a LHR engine and the effects of biodiesel (produced from sunflower oil) usage in the LHR engine on its performance characteristics have been investigated experimentally. The results showed that specific fuel consumption and the brake thermal efficiency were improved and exhaust gas temperature before the turbine inlet was increased for both fuels in the LHR engine.     

Improving combustion characteristics of diesel and biodiesel droplets by graphite oxide addition for diesel engine applications

Graphite oxide (GO) is an important member of the graphene family of carbon nanomaterials with remarkable physical, chemical, and thermal properties. We conducted an experimental investigation on the combustion characteristics of diesel and biodiesel droplets dosed with 0.1% GO. The fuels were tested by a single droplet combustion experiment in which the temporal variation in the burning behavior of a suspended droplet was captured using a high‐speed camera. Numerical analysis of the combustion data suggests that the addition of GO in both fuels resulted in shortened ignition delay (by up to 38.2%), increased burn‐rate constant (by up to 29.4%), lowered peak temperature (by up to 7.8%), and shortened burning period (by up to 11.6%). To illustrate, the burn‐rate constant increased from 0.68 to 0.88 mm²/second, and the burning period reduced from 2.7 to 2.2 seconds when GO was dosed in diesel. By contrast, the ignition delay and peak temperature both decreased from 1.6 to 1.4 seconds and 659 to 611 K, respectively, when GO was added in biodiesel. Our results suggest that the fuel additive–induced benefits could effectively reduce emissions and improve fuel consumption for diesel engine applications.     

An experimental investigation on the application potential of heterogeneous catalyzed Nahar biodiesel and its diesel blends as diesel engine fuels

From the inception of commercialization of biodiesel, feedstock scarcity is a major issue to be pondered upon in developing countries. In this study, an attempt has been made to use an abundantly available underutilized high oil content (67% of Nahar seed kernel) feedstock derived biodiesel in a compression ignition engine. The experimental investigation on diesel engine reveals slightly reduced brake thermal efficiency and excellent exhaust emissions up to 40% blending of Nahar biodiesel with conventional diesel fuel. At full load, compared to diesel fuel, the BTE dropped by 1.64% and 1.83%, whereas the BSFC increased by 5.07% and 6.76% for B30 and B40 blends, respectively. The tested emission parameters such as CO, HC, NOx, and smoke were decreased by 12.66%, 17.99%, 8.31%, and 10.61% for B30 and 4.87%, 12.76%, 7.98%, and 11.78% for B40, respectively, compared to diesel fuel.

Abbreviation: BD: Biodiesel; DF: Diesel fuel     

Performance of a stationary diesel engine using loofah (Luffa cylindrica,L.) biodiesel

A stationary diesel engine using loofah ethyl ester (biodiesel) was studied and evaluated. Loofah biodiesel was obtained by reacting loofah oil with ethanol in a two-step transesterification process. The loofah biodiesel produced from ethyl esters was blended with automotive gas oil at 0–20% mix with 5% increment of loofah ethyl esters. The performance of a constant speed, stationary 2.46 kW diesel engine was evaluated using loofah biodiesel at five loading conditions (0%, 25%, 50%, 75% and 100% of full load). The engine torque, speed, exhaust gas temperature, brake-specific fuel consumption, the brake thermal efficiency and fuel equivalent power ranged from 1.47 to 8.47 Nm, 1300–1500 rev/min, 65–420 °C, 526.24–684.99 g/kWh, 21.91–27.1% and 51.35–33.24%, respectively, when using all the loofah biodiesel samples at all loading conditions. Loofah biodiesel is suitable to fuel a diesel engine.     

Performance of biodiesel/higher alcohols blends in a diesel engine

Alcohols extensively used in internal combustion engines are important renewable and sustainable energy resources from environmental and economical perspectives. Besides, bio production of alcohols decreases consumption of fossil‐based fuels. Although there are many studies with regards to the use of lower alcohols such as methanol and ethanol in internal combustion engines, there are a limited number of investigations with higher alcohols. Higher alcohols such as propanol, n‐butanol, and 1‐pentanol are part of the next generation of biofuels, given they provide better fuel properties than lower alcohols. Biodiesel–higher alcohol blends can be used in diesel engines without any engine modification but need to be tested under various engine conditions with long periods in order to evaluate their impacts on engine performance and environmental pollutants. The objective of this study was to evaluate the effect of using propanol, n‐butanol, and 1‐pentanol in waste oil methyl ester (B100) on engine performance and exhaust emissions of a diesel engine running at different loads (0, 3, 6, and 9 kW) with a fixed engine speed (1800 rpm). Test fuel blends were prepared by adding propanol, n‐butanol, and 1‐pentanol (10 vol.%) into waste oil methyl ester to achieve blends of B90Pr10, B90nB10, and B90Pn10, respectively. According to engine performance and exhaust emissions results, the addition of propanol, n‐butanol, and 1‐pentanol to B100 had the effect of increasing brake specific fuel consumption and exhaust gas temperatures. The brake thermal efficiency (BTE) decreased for B90Pr10 and B90nB10, while B90Pn10 showed a slight increase in BTE as compared with B100. When compared with B100, B90Pr10, B90nB10, and B90Pn10 decreased carbon monoxide emissions at lower loads while it increased slightly at 9 kW load. The decrement in oxides of nitrogen emission was observed at whole loads for B90Pr10, B90nB10, and B90Pn10 compared with B100. When considering all loads, B90Pn10 presented the best mean hydrocarbon emission with a reduction of 45.41%. Copyright © 2016 John Wiley & Sons, Ltd.     

Comparison of fuel characteristics of green (renewable) diesel with biodiesel obtainable from algal oil and vegetable oil

To fulfill the need of renewable, sustainable, and cleaner form of fuel, scientists are attracted toward biodiesel and hydrotreated vegetable oil or green (renewable) diesel. Biodiesel is generally obtained from vegetable oil by the process of transesterification while green diesel is obtained by hydrogenation. However, chemically both are completely different and thus their physical properties are highly affected. In present work, authors have compared the important properties of Pongamia biodiesel, algal biodiesel and hydrotreated vegetable oil. It is observed that both the biofuels may be blended for use in diesel engines as this will complement their fuel characteristics.     

Exergy analysis of small DI diesel engine fueled with waste cooking oil biodiesel

ABSTRACT

This study investigates the merits of exergy analysis over energy analysis for small direct injection (DI) diesel engine using the blend of waste cooking oil biodiesel and petroleum diesel. Taguchi’s “L’ 16” orthogonal array has been used for the design of experiment. The engine tested at different engine speeds, load percentages, and blend ratios, using the waste cooking oil biodiesel. Basic performance parameters and fuel input exergy, exergetic efficiency (second law efficiency), exergy associated with heat transfer, exergy associated with the exhaust gas and destruction of exergy are calculated for each blend of waste cooking oil biodiesel and diesel. Results show that the optimum operating conditions for minimum brake-specific fuel consumption (BSFC) and exergy destruction are achieved when engine speed at 1900 rev/min, load percentage is 75%, and the engine is fueled with B40.     

Emission analysis of diesel engine fueled with soybean biodiesel and its water blends

The present study is carried out to formulate stable water-in-soybean biodiesel emulsion fuel and investigate its emission characteristics in a single cylinder diesel engine. Four types of emulsion fuels, which consist of a different percentage of water (5%, 10%, 15%, and 20%) in soybean biodiesel, were prepared with suitable surfactant and properties were measured. The physicochemical properties are on par with EN 14214 standards. The experimental result of test fuels indicates that the soybean biodiesel promotes a lower level of hydrocarbon (HC), carbon monoxide (CO) and smoke emissions compared to base diesel except for nitrogen oxide (NOx) emission. Increase in water concentration with soybean biodiesel significantly reduces the NOx emission and smoke opacity. The HC and CO emissions are further reduced with emulsified biodiesel up to 10% water concentration and beyond that limit, marginal increases are recorded. Overall, it is observed that inclusion of water with soybean biodiesel reduces the HC, CO, NOx and smoke emissions when compared to base diesel and soybean biodiesel, and 10% water in soybean biodiesel is an appropriate solution to reduce the overall emissions in the soybean-fuelled diesel engine.     

Application of response surface methodology to optimize diesel engine parameters fuelled with pongamia biodiesel/diesel blends

ABSTRACT

In the present scenario, the rate of fossil fuel consumption is very high and increasing rapidly which lead to a further increase in air pollution levels. Due to an increase in pollution level, researchers are striving to discover some cleaner and environment-friendly fuels for the diesel engines. This study was focused on the optimization of the input parameters of the diesel engine running on pongamia biodiesel for improvement in the engine performance. The input parameters selected for optimization were fuel injection pressure, fuel injection timing, pongamia biodiesel blends, and engine load with respect to BTE, BSFC, exhaust gas temperature, and P_max. An experimental analysis was performed according to the response surface methodology technique. The best engine input parameters setting for getting optimum performance was found at fuel injection timing 25 bTDC, fuel injection pressure 226 bar, 40% of pongamia biodiesel blending, at 74% of maximum rated engine load. Experimental and optimized results of the output responses at optimum input parameters were compared and found in the suggested error range.