直喷柴油机燃用生物柴油/柴油混合燃料适应性研究

在AVL标准试验台架上研究了掺混不同比例生物柴油混合燃料对DW10TD四缸电控柴油机动力性、经济性及排放性的影响.研究结果表明,发动机在不作任何改动的前提下,可实现稳定运转;发动机燃用B10的动力与原柴油机相当,燃用B20,B30时动力与燃用B0时相比下降幅度在3%以内.随着柴油中生物柴油添加比例的增大,发动机有效燃油消耗率增大,但发动机燃烧有效热效率有所改善.发动机燃用掺混生物柴油混合燃料对发动机碳烟排放有显著的改善作用;CO和NOx排放在中小负荷与原柴油机相当,大负荷时CO排放随着混合燃料中生物柴油添加比例的增高而减少,而NOx排放则随着生物柴油添加比例的增大而升高;THC排放在中小负荷随着生物柴油添加比例升高而下降.大负荷下燃用各种燃料THC排放基本相当.     

非直喷式增压柴油机燃用生物柴油的性能与排放特性

研究了非直喷式增压柴油机燃用柴油一生物柴油混合燃料的性能和排放特性。未对原机作任何调整和改动,研究了不同生物柴油掺混比例的混合燃料对功率、油耗、烟度和NOx排放的影响。结果表明：非直喷式柴油机燃用生物柴油后柴油机功率略有下降,油耗有所上升,烟度大幅下降,NOx排放增加明显。油耗、烟度和NOx的变化均与生物柴油掺混比例呈线性关系,合适的生物柴油掺混比例即可以保持柴油机的性能,又可有效地降低碳烟排放,且不引起NOx排放的显著变化。对于该增压柴油机,掺混生物柴油对外特性下的排放影响最大,影响最小的为标定转速下的负荷特性。不论是全负荷还是部分负荷,燃用生物柴油时低速下的烟度降低和NOx上升幅度均比高速时大,而同转速下高负荷时烟度降低和NOx上升更为明显。     

掺混含氧燃料对柴油机氧化催化器+催化型柴油机颗粒捕集器氧化及再生特性的影响

为了研究掺烧含氧燃料对柴油机排放及柴油机氧化催化器(DOC)耦合催化型柴油机颗粒捕集器(CDPF)后处理系统低温氧化特性与再生特性的影响,基于一台4缸高压共轨柴油机,选取国五柴油、15%生物柴油-柴油(D85B15)、15%正戊醇-柴油(D85P15)、20%正戊醇-柴油(D80P20)作为燃料,在1 900m海拔环境下进行了试验。研究表明:在外特性工况下,与柴油相比,燃用D85B15和D85P15的柴油机动力性略有下降,燃用D85P15的柴油机有效热效率最高。燃用D85B15的NO_x排放略低于柴油,最高降低3.33%;而D85P15的NO_x排放有所增加,最高增加2.85%。在低负荷工况下燃用国五柴油时DOC+CDPF对CO的转化效率明显高于燃用D80P20时,2 000r/min时燃用柴油时CO转化效率高达96.8%,而D80P20只有36.9%。低速高负荷工况下燃用国五柴油与D80P20时,DOC对排气温度的提升作用均比较明显,平均提升41.8℃和42.5℃。燃用D80P20时DOC+CDPF压差升高较慢,压差最高比燃用国五柴油低6kPa,DOC后端平均温度比燃用国五柴油高10℃。柴油机燃用D80P20在高负荷尤其是低转速高负荷时可有效降低颗粒物排放,降低DOC+CDPF压差。     

柴油机燃用生物柴油的经济性与排放特性试验研究

在DL190-12单缸柴油机上进行了燃用生物柴油与纯柴油的经济性与排放特性对比试验研究。试验结果表明:柴油机燃用生物柴油时,有效燃油消耗率升高约11%~15%,当量燃油消耗率中小负荷时略高于纯柴油水平,大负荷时趋近于纯柴油水平;NOx排放量在中小负荷时趋于纯柴油水平,而大负荷时的排放量较纯柴油升高约14%~20%;CO排放量低于纯柴油水平,最高下降幅度约为11%;THC排放量低于纯柴油水平,下降幅度约18%~47%,燃用生物柴油的炭烟排放较纯柴油大幅度下降,最高下降幅度约50%。     

直喷式轿车柴油机燃用生物柴油的排放特性

在直喷式柴油机和装有该型号柴油机的轿车上燃用柴油/生物柴油混合燃料,未对原机作任何调整,研究了不同生物柴油掺混比例的混合燃料对烟度、CO、THC、NOx和CO2排放的影响.结果表明,直喷式柴油机和轿车燃用生物柴油后,烟度大幅下降,THC排放明显减少;烟度和THC的变化均与生物柴油掺混比例呈线性关系.柴油机CO排放在小于20%负荷下,随着生物柴油的比例增高逐渐增加;在大于20%负荷时,CO排放随着混合燃料中生物柴油的比例增高而减少;在轿车上,只有低比例掺烧(10%)的CO排放有所下降.柴油机上的NOx排放在低比例掺烧(10%)时下降,而在较高比例掺烧(30%)时,NOx排放升高;在轿车上,NOx排放都有所升高.在柴油机上,燃用生物柴油混合燃料后,CO2排放的总体趋势在减少,但减少比例随生物柴油掺混比例的不同而不同;在整车上,只有低比例掺烧(10%)时CO2排放降低,而较高比例掺烧(30%)时CO2排放升高.     

重型车用柴油机燃用乳化柴油的燃烧与排放特性试验研究

在不改变发动机任何参数的情况下,对高压共轨重型车用柴油机分别燃用柴油和乳化柴油的燃烧与排放特性进行了对比试验研究。试验结果表明:与纯柴油相比,乳化柴油在试验工况下着火滞燃期延长,瞬时放热率峰值提高,燃烧持续期变短;缸内最高压力在低负荷时较柴油高,但在高负荷时较柴油低;在全负荷下,相比于柴油,燃用乳化柴油有效功率平均降低了16.90%,但发动机有效热效率平均提高了2.42%;燃用乳化柴油在常用转速1 800 r/min的负荷范围内时,NOx和碳烟排放分别比柴油平均降低了12.77%和58.90%,改善了NOx和碳烟排放的权衡曲线关系;高负荷时,燃用乳化柴油的CO排放减少,但HC排放增加。     

柴油机单环芳香烃类污染物的试验研究

在直喷式柴油机上,采用活性炭吸附-溶剂解吸/气相-质谱联用的方法,测量了燃用柴油、生物柴油及其调和油B50(体积比为50%生物柴油和50%柴油)排气中的单环芳香烃类污染物(MAHs)。研究结果表明:燃烧柴油时,苯和MAHs排放的平均浓度分别为0.53μg/L和5.51μg/L。与柴油相比,燃烧生物柴油可大幅降低MAHs排放的平均浓度,降低幅度为76%。燃烧柴油时,苯、甲苯等污染物的排放浓度随着负荷的增大而降低,中负荷时达到最低值,随着负荷进一步增大,其排放浓度明显增大,二甲苯排放浓度随负荷变化不明显。燃烧生物柴油和生物柴油调和油时,苯、甲苯和乙苯的排放浓度随负荷变化规律与燃烧柴油时基本一致。     

在直喷式柴油机上燃用低比例生物柴油和柴油的试验研究

在原直喷式柴油机结构和参数不做任何改变情况下,燃用低比例生物柴油和高比例柴油的混合燃料进行试验研究.试验结果表明:发动机燃用20%生物柴油和80%柴油的混合燃料与柴油相比较,在外特性下,B20功率和扭矩均比柴油低,当量油耗率低速时要低,高速时高.在外特性和1800 r/min负荷特性下,混合燃料碳烟、CO和HC排放均降低,NOx排放(除少数工况外)略有增加.该混合燃料对降低柴油机碳烟、C0和HC排放十分有利.     

低配比GTL柴油和生物柴油的燃烧颗粒排放特性

以一台电控高压共轨柴油机为样机,研究了柴油机分别燃用低配比天然气合成油(GTL柴油)、低配比生物柴油混合燃料的颗粒排放特性。所用燃料分别为纯柴油、GTL柴油体积掺混比为10%的燃料(G10)、生物柴油体积掺混比10%的燃料(B10)。研究了该机燃用这三种燃料的烟度、颗粒数量及粒径分布特性。研究结果表明:柴油机燃用G10燃料、B10燃料的排气烟度均低于纯柴油,B10燃料的排气烟度低于G10燃料;柴油燃用三种燃料的排气颗粒数量大多呈明显的单峰或者双峰对数分布。B10燃料的核态颗粒数量在各工况下均为最高,G10燃料在各负荷下全粒径范围内聚集态颗粒与核态颗粒的数量几乎均为最低。随负荷增加,柴油机颗粒总数量呈总体上升趋势。各工况下,柴油机燃用B10燃料的颗粒总数量最高,G10燃料的颗粒总数量最低,核态颗粒数量的差异在其中占主导地位。     

增压柴油机燃用生物柴油的排放特性

通过对比实验研究了增压柴油机燃烧生物柴油和普通柴油对发动机动力性、经济性和排放特性的影响,研究结果表明：对于实验发动机,在对喷油泵不做任何调整时,直接燃烧生物柴油对柴油机动力性的影响小于5％;无论在全负荷还是在部分负荷工况下,燃用生物柴油均能大幅度降低柴油机的排气可见污染物、PT、CO和HC排放,但会引起NOx排放量的上升,通过适当推迟喷油提前角能明显降低燃用生物柴油时发动机的COx排放,同时还能保留排气可见污染物低、PT、CO和HC排放低的优点,但对发动机动力性的影响却不大,研究表明生物柴油是理想的可再生清洁燃料。     

共轨柴油机燃用不同配比生物柴油的性能与排放特性

对某共轨柴油机燃用石化柴油、生物柴油及其混合燃料的动力性、经济性和排放特性进行了研究.在未对原机做任何改动的情况下,分别燃用了0%、5%、10%、20%和100%的5种不同体积配比的餐饮废油制生物柴油与石化柴油的混合燃料,分析比较了不同生物柴油配比对发动机功率、燃油消耗率,以及CO、HC、NO_x和烟度排放的影响.研究表明:共轨柴油机燃用生物柴油与石化柴油混合燃料后,功率略有下降,燃油消耗率有所上升;烟度、CO和HC排放减少,且随着生物柴油掺混比例的升高而降低;NO_x排放上升,且随着生物柴油掺混比例的升高而增加.     

推迟供油提前角对生物柴油发动机燃烧和排放性能的影响

在直喷式增压柴油机上进行了供油提前角对生物柴油发动机动力性、经济性和排放性能影响的研究。试验结果表明:与柴油相比,推迟供油提前角后生物柴油的动力性下降,燃油经济性恶化,NO_x和烟度排放均有不同程度的降低。推迟供油提前角对生物柴油的喷油压力和滞燃期影响不大,但喷油始点和燃烧始点均迟于柴油。与柴油相比,推迟供油提前角后最高气缸压力下降,放热峰值出现时刻提前,指示热效率降低。燃烧始点与NO_x排放的相关性最大,喷油始点和放热峰值出现时刻也与NO_x排放呈弱相关性。     

一种新型生物柴油的探讨

利用乙二醇乙醚和精制大豆油合成出一种新型生物柴油——乙二醇乙醚豆油单酯,并利用单缸机研究了这种新型生物柴油对发动机动力性、经济性和排放性能的影响,结果表明：燃烧这种新型生物柴油后,柴油机动力性几乎不变,耗油率有所增加;排气烟度、CO和HC排放水平大幅度降低,而NOx排放略有增加。     

Effect of diethyl ether additive in Jatropha biodiesel-diesel fuel blends on the variable compression ratio diesel engine performance and emissions characteristics at different loads and compression ratios

An investigational analysis was performed to assess the effect of diethyl ether (DEE) that acts as an oxygenated additive in Jatropha biodiesel and diesel fuel blends on the performance enhancement and emission reduction of a variable compression ratio (CR) diesel engine. The DEE (10% vol) is added to different concentration levels of Jatropha biodiesel (B5, B10, and B20). The Jatropha biodiesel (JME) is prepared by the transesterification reaction and DEE is prepared through acid distillation of ethanol. The various tests were conducted by varying the loads at 25%, 50%, 75%, and 100% (3, 6, 9, and 12 kg). The DEE was entirely miscible with diesel and Jatropha biodiesel, the addition of DEE increases the cetane and calorific value, kinematic viscosity of the fuel blends compared with neat diesel or Jatropha biodiesel. The results illustrate that at higher loads and CRs, the engine performance parameters such as brake thermal efficiency enhances and reduces the brake-specific fuel consumption for DEE-Jatropha biodiesel-diesel fuel blends. Blend A3 (10% DEE + 20% JME + 70% diesel) demonstrated an overall improvement in the engine performance parameters and emission characteristics compared with A1, A2, and diesel fuel blends. It is concluded that the DEE-JME-diesel fuel blend is a promising source of fuel for diesel engine at maximum load.     

A study on the performance and emission of a diesel engine fueled with Jatropha biodiesel oil and its blends

Biodiesel either in neat form or as a mixture with diesel fuel is widely investigated to solve the twin problem of depletion of fossil fuels and environmental degradation. The main objective of the present study is to compare performance, emission and combustion characteristics of biodiesel derived from non edible Jatropha oil in a dual fuel diesel engine with base line results of diesel fuel. The performance parameters evaluated were: brake thermal efficiency, brake specific fuel consumption, power output. As a part of combustion study, in-cylinder pressure, rate of pressure rise and heat release rates were evaluated. The emission parameters such as carbon monoxide, carbon dioxide, un-burnt hydrocarbon, oxides of nitrogen and smoke opacity with the different fuels were also measured and compared with base line results. The different properties of Jatropha oil after transestrification were within acceptable limits of standards as set by many countries. The brake thermal efficiency of Jatropha methyl ester and its blends with diesel were lower than diesel and brake specific energy consumption was found to be higher. However, HC, CO and CO₂ and smoke were found to be lower with Jatropha biodiesel fuel. NO_x emissions on Jatropha biodiesel and its blend were higher than Diesel. The results from the experiments suggest that biodiesel derived from non edible oil like Jatropha could be a good substitute to diesel fuel in diesel engine in the near future as far as decentralized energy production is concerned. In view of comparable engine performance and reduction in most of the engine emissions, it can be concluded and biodiesel derived from Jatropha and its blends could be used in a conventional diesel engine without any modification.     

6BTA 5.9 G2-1 Cummins engine performance and emission tests using methyl ester mahua (Madhuca indica) oil/diesel blends

Neat mahua oil poses some problems when subjected to prolonged usage in CI engine. The transesterification of mahua oil can reduce these problems. The use of biodiesel fuel as substitute for conventional petroleum fuel in heavy-duty diesel engine is receiving an increasing amount of attention. This interest is based on the properties of bio-diesel including the fact that it is produced from a renewable resource, its biodegradability and potential to exhaust emissions. A Cummins 6BTA 5.9 G2- 1, 158 HP rated power, turbocharged, DI, water cooled diesel engine was run on diesel, methyl ester of mahua oil and its blends at constant speed of 1500 rpm under variable load conditions. The volumetric blending ratios of biodiesel with conventional diesel fuel were set at 0, 20, 40, 60, and 100. Engine performance (brake specific fuel consumption, brake specific energy consumption, thermal efficiency and exhaust gas temperature) and emissions (CO, HC and NOx) were measured to evaluate and compute the behavior of the diesel engine running on biodiesel. The results indicate that with the increase of biodiesel in the blends CO, HC reduces significantly, fuel consumption and NOx emission of biodiesel increases slightly compared with diesel. Brake specific energy consumption decreases and thermal efficiency of engine slightly increases when operating on 20% biodiesel than that operating on diesel.     

Emission and engine performance analysis of a diesel engine using hydrogen enriched pomegranate seed oil biodiesel

The aim of this study is to determine the availability of pomegranate seed oil biodiesel (POB) as an alternative fuel in diesel engines and evaluate engine performance and emission characteristics of pure hydrogen enriched POB using diesel engine. For this purpose, the intake manifold of the test engine was modified and hydrogen enriched intake air was supplied throughout the experiments. Physical properties of POB and its blend with diesel fuel were also determined. The results showed that measured physical properties of POB are comparable with diesel fuel. According to engine performance experiments, although POB utilization has slight undesirable effects on some engine performance parameters such as brake power output and specific fuel consumption, it can be used as alternative fuel in diesel engines, by this way CO emission can be improved. Finally, hydrogen enrichment experiments indicated that pure hydrogen addition causes a slight improvement in both engine performance and exhaust emissions.     

Biodiesel production from inedible animal tallow and an experimental investigation of its use as alternative fuel in a direct injection diesel engine

In this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NO_x), sulphur dioxide (SO₂) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NO_x emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification.     

The effects of turbocharger on the performance and exhaust emissions of a diesel engine fuelled with biodiesel

This paper investigates the effects of turbocharger on the performance of a diesel engine using diesel fuel and biodiesel in terms of brake power, torque, brake specific consumption and thermal efficiency, as well as CO and NO_x emissions. For this aim, a naturally aspirated four-stroke direct injection diesel engine was tested with diesel fuel and neat biodiesel, which is rapeseed oil methyl ester, at full load conditions at the speeds between 1200 and 2400 rpm with intervals of 200 rpm. Then, a turbocharger system was installed on the engine and the tests were repeated for both fuel cases. The evaluation of experimental data showed that the brake thermal efficiency of biodiesel was slightly higher than that of diesel fuel in both naturally aspirated and turbocharged conditions, while biodiesel yielded slightly lower brake power and torque along with higher fuel consumption values. It was also observed that emissions of CO in the operations with biodiesel were lower than those in the operations with diesel fuel, whereas NO_x emission in biodiesel operation was higher. This study reveals that the use of biodiesel improves the performance parameters and decreases CO emissions of the turbocharged engine compared to diesel fuel.