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.     

Performance of a common rail diesel engine using biodiesel of waste cooking oil and gasoline blend

High viscosity, high pour point and low volatility are the major application blocks for biodiesel. In this study gasoline is mixed with biodiesel and they can be soluble with each other at any proportion. Combustion and emission characteristics are investigated on a turbocharged, in-line 6-cylinder, common rail diesel engine. Results showed that pour points, viscosities and distillation temperatures obviously decrease with gasoline ratio. Peak combustion pressures of biodiesel/gasoline blend fuels increase slightly. Ignition delays, peak heat release rates and combustion temperatures increase at partial and medium loads. HC and CO emissions increase at partial and medium loads and drop at high loads. NO_X emissions of blend fuels grow by 4.2% and 6.7% compared with biodiesel averagely at 1400r/min, while soot emissions decline by 31.6% and 38.6%. For ultrafine particles (<220 nm), diameters to peak number concentration of blend fuels are smaller than that of biodiesel. Number concentrations decrease by 30% and 49% averagely compared to biodiesel. Especially, gasoline plays a significant reduction role on ultrafine particles at low and medium loads and soot emissions at high loads.     

相同氧含量醇类混合燃料燃烧和排放特性差异研究

对一台4缸发动机燃用相同氧浓度的不同醇类混合燃料进行了试验研究,以对比不同三元燃料柴油机在相同转速不同负荷情况下的燃烧特性和常规排放的差异。试验结果表明:甲醇混合燃料在醇类混合燃料中获得最高的燃烧压力,而丁醇混合燃料的热释放率最高。与普通柴油相比,戊醇混合燃料在不同混合物中具有相对最佳的CO和未燃碳氢排放,甲醇混合燃料可获得最优的氮氧化物排放;乙醇混合燃料减小颗粒物效果明显,最大可以减少22.4%～55.6%的颗粒物数量浓度和3.4%～12.8%的颗粒物粒径,其中乙醇混合燃料的核态颗粒物和聚集态颗粒物排放量也最低,戊醇混合燃料达到最高(除高负荷外)。     

煤制-石化柴油的排放特性研究

在CA4DF3R-13高压共轨柴油机上研究了欧Ⅲ石化柴油、煤制-石化混合柴油和煤制柴油(CTL)的排放性能,以及添加不同剂量的润滑改进剂和十六烷值改进剂对煤制-石化柴油排放性能的影响,结果表明,CTL比油耗比石化柴油略高,排放基本相同,添加十六烷值改进剂可以改变比油耗,添加润滑改进剂可以改变排放。     

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.     

Effects of variable O2 concentrations and injection pressures on the combustion and emissions characteristics of the petro-diesel and hydrotreated vegetable oil-based fuels under the simulated diesel engine condition

This experimental research investigates the effects of variable O₂ concentrations and injection pressures on the combustion and emissions characteristics of the diesel (B7) and the hydrotreated vegetable oil (HVO)-based fuels. The O₂ concentrations included 21%, 15% and 10% O₂, while the injection pressures were 80 and 120 MPa. The experimental fuels were the diesel fuel (B7), the neat HVO, the 20%, 50% and 80% HVO (by mass fraction) blended with the diesel. The experiments were carried out in a rapid compression-expansion machine (RCEM) under the direct injection (DI) diesel combustion condition. The analysis was undertaken using the two-color method. The experimental results indicated that the ignition delay, the heat release rate, the flame temperature, the soot density-KL factor, the NO_x and soot-out emissions were inversely correlated to the HVO fraction in the blend. In addition, the findings revealed the similar flame profiles in which the higher flame temperature region and the darker KL density were concentrated around the spray flame upstream, regardless of the HVO mixing ratio. Besides, the decrease in the O₂ concentration resulted in the lower heat release rate, integral heat release, flame temperature, KL factor and NO_x emissions but the longer ignition delay and higher soot concentration, with the highest soot concentration observed under the 15% O₂ environment. Nevertheless, the higher pressure differential (i.e. between the injection pressure and the ambient pressure) contributed to the shorter ignition delay, higher heat release rate, early peak of the flame temperature, wider combustion area, faster soot oxidation rate and higher NO_x production.     

十六烷值对柴油机冷起动和排放影响的试验探讨

柴油的十六烷值对柴油机冷起动和排放有一定影响。本文通过在柴油内加入不同品种和数量的添加剂形成的五种不同十六烷值的柴油进行试验，比较了十六烷值对发动机的最高气缸压力、放热率、冷起动性能、尾气中碳氢化合物和液态与固态微粒排放的影响。     

二甲醚均质压燃燃烧过程的试验研究

在一台单缸直喷柴油机上进行了二甲醚(DME)均质压燃(HCCl)燃烧过程的试验．研究结果表明，进气中加入30％的惰性气体CO2,发动机实现HCCl运转的负荷范围从0．05MPa扩展到0．35MPa．二甲醚在HCCl模式下表现出明显的双阶段着火特性，增加惰性气体的浓度，第一阶段着火始点滞后，燃烧放热峰值降低，燃烧持续期延长．排放测试表明，HCCl模式下发动机的NOx排放接近于零，可实现无碳烟排放，但CO和HC排放较高．     

利用实测放热规律研究十六烷值改进剂对柴油机着火特性和燃烧过程的影响

通过基础油和加剂油实测放热规律的对比,就自行研制的ｃ－ＲＯＮＯ２柴油十六烷值改进剂对柴油机着火和燃烧过程的影响进行了深入的分析。结果表明,十六烷值改进剂能加速柴油的氧化过程,缩短着火滞燃期,使预混合燃烧期和扩散燃烧期的放热百分经得到合理分配,从而改善了柴油机的着火和燃烧特性。     

喷射参数对二甲醚PPCCI发动机燃烧与排放特性的影响

在一台6缸增压电控共轨二甲醚发动机上进行试验,研究了预喷时刻、预喷燃料量、喷射压力、主喷时刻等喷射参数对二甲醚部分预混合充量压缩燃烧(PPCCI)发动机燃烧与排放特性的影响。试验结果表明:随预喷时刻提前,缸内压力峰值降低,二甲醚发动机缸内燃烧由两阶段放热转变为PPCCI三阶段放热,氮氧化物(NOx)排放显著降低,HC和CO排放升高;随预喷射燃料量增加,缸内压力峰值及预混合燃烧的冷焰反应和热焰反应速率明显增大,NOx排放逐渐降低,HC和CO排放显著升高;随喷射压力降低,预混合燃烧热焰反应速率增加,主喷扩散燃烧始点推迟,扩散燃烧放热率峰值和NOx排放明显降低,HC和CO排放升高;随主喷时刻推迟,预喷预混合燃烧几乎没有变化,主喷扩散燃烧延后,缸内压力峰值和放热率峰值降低,NOx排放显著降低,HC和CO排放升高。     

Experimental evaluation of hydrogen enrichment in a dual-fueled CRDI diesel engine

The influence of hydrogen enrichment on the dieselengine fueled with diesel and palm biodiesel blend (P20) is investigated in this study. The hydrogen is injected into the intake manifold at different flow rates of 7 lpm and 10 lpm for each loading condition of 30%, 60%, 80%, 90%, and 100%, respectively. Hydrogen enrichment improves the BTE and BSEC due to its high calorific value and decreases emissions like HC, CO, and CO₂ due to its carbon-free structure. However, due to a rise in EGT, NO_x emission has increased. With the addition of hydrogen, combustion properties such as in-cylinder pressure (ICP), heat release rate (HRR), and ignition delay (ID) improve while the combustion duration (CD) drops. Compared to P20 fuel,P20 + 10H₂ has a 28% increase in BTE and a 20% decrease in BSEC at 90% load. Similarly, HC, CO, and CO₂ emissions decrease by 16%, 35%, and 12%, while NO_x emission increases by 13% compared to P20. At full load, P20 + 10H₂increasesin-cylinder pressureand heat release ratebyupto 1–5%, while CD decreases by 12.5% compared to the P20 blend.     

一种新型含氧燃料燃烧与排放性能研究

开展了柴油机燃用柴油／乙二醇单丁醚混合燃料的燃烧与排放性能研究。试验结果表明：在柴油机中加入一定比例的乙二醇单丁醚（NBE）,柴油机热效率得到明显提高,着火略有延迟,燃烧速度加快,燃烧持续期缩短。烟度和CO排放大幅度降低。加入159／5～25％NBE时,烟度下降43．9％～759／5,CO排放在高负荷下降46．5％～56％,HC排放也不同程度降低,NOx排放稍有下降。试验结果显示了柴油机燃用乙二醇单丁醚在降低排放方面的优越性。     

Effect of diethyl ether and ethanol additives on the combustion and emission characteristics of biodiesel-diesel blended fuel engine

An experimental investigation is conducted to evaluate the effects of using diethyl ether and ethanol as additives to biodiesel/diesel blends on the performance, emissions and combustion characteristics of a direct injection diesel engine. The test fuels are denoted as B30 (30% biodiesel and 70% diesel in vol.), BE-1 (5% diethyl ether, 25% biodiesel and 70% diesel in vol.) and BE-2 (5% ethanol, 25% biodiesel and 70% diesel in vol.) respectively. The results indicate that, compared with B30, there is slightly lower brake specific fuel consumption (BSFC) for BE-1. Drastic reduction in smoke is observed with BE-1 and BE-2 at higher engine loads. Nitrogen oxide (NOx) emissions are found slightly higher for BE-2. Hydrocarbon (HC) emissions are slightly higher for BE-1 and BE-2, but carbon monoxide (CO) are slightly lower. The peak pressure, peak pressure rise rate and peak heat release rate of BE-1 are almost similar to those of B30, and higher than those of BE-2 at lower engine loads. At higher engine loads the peak pressure, peak pressure rise rate and peak heat release rate of BE-1 are the highest and those of B30 are the lowest. BE-1 reflects better engine performance and combustion characteristics than BE-2 and B30.     

EGR对生物柴油/异丁醇混合燃料燃烧与排放的影响

在一台四缸四冲程水冷高压共轨柴油机上研究了生物柴油/异丁醇混合燃料在不同EGR率下的燃烧及排放特性.试验结果表明:随EGR率的升高,缸内压力和放热率峰值降低,燃料滞燃期延长,燃烧持续期先缩短后延长,NO排放与核模态颗粒物数密度降低;当EGR率小于6%时,CO和HC污染物的排放都保持在较低水平.相较于生物柴油,燃用混合燃料降低CO污染物的排放;随异丁醇掺混比例的增加,缸内压力与放热率峰值逐渐升高,CO排放降低,但HC与NO的排放逐渐升高,核模态颗粒物数密度升高,积聚态颗粒物数密度和颗粒物质量浓度有不同程度的下降.     

Preparation,characterization, engine combustion and emission characteristics of rapeseed oil based hybrid fuels

In this study, hybrid fuels consisting of rapeseed oil/diesel blend, 1% aqueous ethanol and a surfactant (oleic acid/1-butanol mixture) were prepared and tested as a fuel in a direct injection (DI) diesel engine. The main fuel properties such as the density, viscosity and lower heating value (LHV) of these fuels were measured, and the engine performance, combustion and exhaust emissions were investigated and compared with that of diesel fuel. The experimental results showed that the viscosity and density of the hybrid fuels were decreased and close to that of diesel fuel with the increase of ethanol volume fraction up to 30%. The start of combustion was later than that of diesel fuel and the peak cylinder pressure, peak pressure rise rate and peak heat release rate were higher than those of diesel fuel. The brake specific fuel consumption (BSFC) of hybrid fuels was increased with the volume fraction of ethanol and higher than that of diesel. The brake specific energy consumption (BSEC) was almost identical for all test fuels. The smoke emissions were lower than those for diesel fuel at high engine loads, the NO_x emissions were almost similar to those of diesel fuel, but CO and HC emissions were higher, especially at low engine loads.     

聚甲氧基二甲醚-甲醇混合燃料的燃烧与排放特性研究

将甲醇按体积比0、10%、20%、30%分别掺混到聚甲氧基二甲醚(polyoxymethylene dimethyl ethers,PODE)中制备出PODE-甲醇混合燃料,并依次标记为M0、M10、M20和M30,在一台高压共轨发动机上研究了最大转矩转速不同负荷下混合燃料的缸内燃烧过程和排放性能。结果表明:在PODE中添加甲醇后,各负荷下缸内压力降低,滞燃期逐渐延长,放热始点推迟。低负荷和中负荷时甲醇体积比的增加会使放热率峰值先增加后减小,而高负荷下放热率峰值却逐渐升高。甲醇体积比较低时,各负荷下燃烧持续期缩短;当甲醇体积比为30%时,中低负荷下燃烧持续期延长,各负荷下燃烧重心(CA50)推迟。掺烧甲醇可以降低NO_x浓度,M30较M0降低幅度为28.1%;而随甲醇体积比的增加,各负荷下HC和CO排放量均呈上升趋势,烟度则先减小后增大。甲醇的低温氧化使混合燃料的甲醛排放量上升,同时NO_2排放量及NO_2占NO_x比例随甲醇体积比的升高而增加,与纯PODE相比,低负荷下M30的NO_2排放量和NO_2占NO_x比例增幅分别为65%和107%。     

Effect of ethanol–diesel blend fuels on emission and particle size distribution in a common-rail direct injection diesel engine with warm-up catalytic converter

In this study, the exhaust gas from a common-rail direct injection diesel engine was investigated both upstream and downstream warm-up catalytic converters (WCC). Three different types of ultra-low sulfur fuels (ethanol–diesel blend, ethanol–diesel blend with cetane improver and pure diesel) were tested in this study. The objective of the work was to study the engine performance and the formation of THC (total hydro carbon), CO (carbon monoxide), NO_x (nitrogen oxides), smoke and PM (particulate matters) when using these fuels. THC and CO emissions of the ethanol–diesel blend fuels were slightly increased, and about 50–80% mean conversion efficiencies of THC and CO on catalysts were achieved in the ECE R49 13-mode cycle. Smoke was decreased by more than 42% in the entire ECE 13-mode cycles. From the measurement of scanning mobility particle sizer (SMPS) for the particle size range of 10–385 nm, the total number and total mass of the PM of the ethanol–diesel blend fuels were decreased by about 11.7–15% and 19.2–26.9%, respectively.     

Effect of different volume fractions of ammonia on the combustion and emission characteristics of the hydrogen-fueled engine

Hydrogen internal combustion engines (ICE) will play an important role in reducing carbon emissions, but low power density and abnormal combustion problems are the main obstacles restricting the promotion of hydrogen ICE. Ammonia is a low-reactivity renewable fuel. The purpose of this study is to study the effect of different ammonia-added volume fractions on hydrogen ICE. In this experimental study, the combustion and emission characteristics of an engine fueled by a hydrogen/ammonia mixture were evaluated at part-load operating conditions. The experiment was carried out on a modified engine, the engine speed was 1300 rpm, the absolute pressure of the manifold was 61 kPa, and the volume fraction of ammonia added was 5.2%, 7.96%, and 10.68%, respectively. The test results show that the addition of ammonia changes the combustion characteristics of hydrogen. As the volume fraction of ammonia added increases, the flame development period and flame propagation period are both prolonged, and the peak heat release rate decreases. The addition of ammonia increases the power of the engine and reduces the indicated thermal efficiency. At the ignition timing of the maximum braking torque, as the volume fraction of ammonia added increases, the indicated mean effective pressure and indicated thermal efficiency increase. Adding ammonia volume fraction has little effect on Nitrogen oxides (NOx) emissions, and NOx emissions gradually increase with the delay of ignition timing.     

十六烷值改进剂对涡流室柴油机排放特性的影响

将自选研制的有机硝酸酯类十六烷值改进剂以不同浓度加到柴油中,对影响95型涡流室柴油机的排放特性进行了实验研究,结果表明,该十六烷值改进剂可明显降低柴油机NOx的排入;在适宜浓度下,对HC和CO排放没有影响;但使排气烟度有所恶化。实验还测试了该剂对燃油经济性的影响,结果表明,该剂可略微降低柴油机的有效燃油耗。     

Performance and combustion characteristics of biodiesel–diesel–methanol blend fuelled engine

An experimental investigation was conducted to evaluate the effects of using methanol as additive to biodiesel–diesel blends on the engine performance, emissions and combustion characteristics of a direct injection diesel engine under variable operating conditions. BD50 (50% biodiesel and 50% diesel in vol.) was prepared as the baseline fuel. Methanol was added to BD50 as an additive by volume percent of 5% and 10% (denoted as BDM5 and BDM10). The results indicate that the combustion starts later for BDM5 and BDM10 than for BD50 at low engine load, but is almost identical at high engine load. At low engine load of 1500 r/min, BDM5 and BDM10 show the similar peak cylinder pressure and peak of pressure rise rate to BD50, and higher peak of heat release rate than that of BD50. At low engine load of 1800 r/min, the peak cylinder pressure and the peak of pressure rise rate of BDM5 and BDM10 are lower than those of BD50, and the peak of heat release rate is similar to that of BD50. The crank angles at which the peak values occur are later for BDM5 and BDM10 than for BD50. At high engine load, the peak cylinder pressure, the peak of pressure rise rate and peak of heat release rate of BDM5 and BDM10 are higher than those of BD50, and the crank angle of peak values for all tested fuels are almost same. The power and torque outputs of BDM5 and BDM10 are slightly lower than those of BD50. BDM5 and BDM10 show dramatic reduction of smoke emissions. CO emissions are slightly lower, and NO_x and HC emissions are almost similar to those of BD50 at speed characteristic of full engine load.