Performance and emission studies on port injection of hydrogen with varied flow rates with Diesel as an ignition source

Automobiles are one of the major sources of air pollution in the environment. In addition CO₂ emission, a product of complete combustion also has become a serious issue due to global warming effect. Hence the search for cleaner alternative fuels has become mandatory. Hydrogen is expected to be one of the most important fuels in the near future for solving the problems of air pollution and greenhouse gas problems (carbon dioxide), thereby protecting the environment. Hence in the present work, an experimental investigation has been carried out using hydrogen in the dual fuel mode in a Diesel engine system. In the study, a Diesel engine was converted into a dual fuel engine and hydrogen fuel was injected into the intake port while Diesel was injected directly inside the combustion chamber during the compression stroke. Diesel injected inside the combustion chamber will undergo combustion first which in-turn would ignite the hydrogen that will also assist the Diesel combustion. Using electronic control unit (ECU), the injection timings and injection durations were varied for hydrogen injection while for Diesel the injection timing was 23° crank angle (CA) before injection top dead centre (BITDC). Based on the performance, combustion and emission characteristics, the optimized injection timing was found to be 5° CA before gas exchange top dead centre (BGTDC) with injection duration of 30° CA for hydrogen Diesel dual fuel operation. The optimum hydrogen flow rate was found to be 7.5 lpm. Results indicate that the brake thermal efficiency in hydrogen Diesel dual fuel operation increases by 15% compared to Diesel fuel at 75% load. The NO_X emissions were higher by 1–2% in dual fuel operation at full load compared to Diesel. Smoke emissions are lower in the entire load spectra due to the absence of carbon in hydrogen fuel. The carbon monoxide (CO), carbon dioxide (CO₂) emissions were lesser in hydrogen Diesel dual fuel operation compared to Diesel. The use of hydrogen in the dual fuel mode in a Diesel engine improves the performance and reduces the exhaust emissions from the engine except for HC and NO_X emissions.     

推进特性试验下生物乳化柴油对柴油机性能的影响

在柴油机上进行柴油、三种生物乳化柴油(E10、E15和E20)和生物柴油的推进特性试验,就其燃烧特性、动力性、经济性及常规排放特性进行对比。试验结果显示:高转速时,生物乳化柴油的缸内燃烧压力和放热率略低于柴油,缸内燃烧温度有所降低;动力性相比柴油略有下降,仅E10的燃油消耗率比柴油低,B100最高;烟度和NOx排放均有显著降低,且随水和丁醇掺混比例增加而降低; CO和HC排放与柴油基本无差别,整体增加不多。表明:生物乳化柴油作为替代燃料能保证柴油机运行的稳定性,可同时降低柴油机的烟度和NOx排放,具有良好的环境效益和经济效益。     

Investigation on performance,combustion and emission characteristics of biodiesel - Ethanol blends with hydrogen in CI engine

The current research work focus on the utilization of hydrogen as a fuel in CI engine has been increased tremendously, since it is a zero-emission fuel. But higher self-ignition temperature than conventional fuel, makes to operate in dual fuel mode condition in CI engine. The diesel or biodiesel along with hydrogen in a CI engine results in the improvement in the performance but increase of NO. In order to minimize the NO emission, addition of ethanol with jamun B20 biodiesel blend (biodiesel-diesel-ethanol) and two ternary blends such as B20E05 and B20E10 are formed. In the present study, biodiesel along with H₂ is admitted in the CI engine. Ethanol addition reduces combustion temperature and act as cetane improver for the biodiesel. This induces better combustion of the fuel and reduce NO. The biodiesel production from jamun seed is carried out through transesterification process. H₂ of 4 lpm is allowed at the air inlet and jamun B20 blend is injected through the fuel injector. Improvement of brake thermal efficiency and increase in the NO are observed for the hydrogen with biodiesel operated CI engine. The performance and emission behaviors of CI engine done for the test samples. At full load condition (ternary blend) B20E05 assisted H₂ shows the drastic reduction of NO emission of 8.2% than B20 assist H₂ blend. In other hand emission like hydrocarbon, carbon monoxide and smoke opacity show a notable reduction for B20E05 blend assist H₂ than other test sample fuel. The thermal efficiency is 30.98% for B20E05 assist H₂ and it is 7.55% and 4.7% higher than B20 and B20E05 assist H₂ blend respectively.     

Influence of fuel additives on performance of direct-injection Diesel engine and exhaust emissions when operating on shale oil

The article presents the comparative bench testing results of a naturally aspirated four stroke, four cylinder, water cooled, direct injection Diesel engine when running on shale oil that has been treated with multi-functional fuel additives. The purpose of the research is to evaluate the effectiveness of the fuel additives Marisol FT (Sweden) and SO-2E (Estonia) as well as to verify their ability to increase energy conversion and reduce brake specific fuel consumption, contamination and smoke opacity of the exhausts when fuelling the Diesel engine with shale oil.Test results show that application of these additives could be a very efficient means to improve Diesel engine performance on shale oil, especially when operating at the light load range. The brake specific fuel consumption at light loads and speeds of 1400–2000 min⁻¹ reduces by 18.3–11.0% due to the application of the Marisol FT. The additive SO-2E proves to produce nearly the same effect.The total NO_x emission from the fully loaded Diesel engine fuelled with the treated shale oil reduces by 29.1% (SO-2E) and 23.0% (Marisol FT). It is important that the lower NO_x is obtained due to reducing both harmful pollutants, NO and NO₂. The CO emission at rated power increases by 16.3% (SO-2E) and 48.0% (Marisol FT), whereas the smoke opacity of the exhausts increases by 35% and over 2 times, respectively. The effect of the fuel additives on the HC emission seems to be complicated and ambiguous.     

柴油引燃乙醇均质混合气的二元燃料燃烧特性

在一台单缸增压中冷试验柴油发动机上,研究了不同转速和负荷下乙醇在进气道形成均质混合气,然后在气缸内由柴油引燃的二元燃料燃烧特性.结果发现:采用柴油引燃乙醇混合气的二元燃料燃烧方式,在高负荷时预混燃烧量明显增加,扩散燃烧大幅度减少;在低负荷以及整个低速工况下都实现了单峰快速放热.另外,采用这种燃烧模式能够降低绝大部分工况的最高燃烧温度,并缩短高温持续时间.研究还发现,这种二元燃料燃烧大部分工况的最高爆发压力和压力升高率都比原机高,燃烧持续期短于原机,在中高负荷时能大幅度地减少柴油消耗并提高发动机热效率.与原柴油机相比,采用二元燃料燃烧的指示热效率最高提高了11.09%.     

Performance,emission and combustion characteristics of a compression ignition engine operating on neat orange oil

Biomass derived fuels are preferred as alternate fuels for I.C Engines due to their abundant availability and renewable nature. Fuels such as methanol and ethanol have proved to be suitable alternate fuels in the transport sector. In the present work the performance, emission and combustion characteristics of a single cylinder, constant speed, direct injection diesel engine using orange oil as an alternate fuel were studied and the results are compared with the standard diesel fuel operation. Results indicated that the brake thermal efficiency was higher compared to diesel throughout the load spectra. Carbon monoxide (CO) and hydrocarbon (HC) emissions were lower and oxides of nitrogen (NO_x) were higher compared to diesel operation. Peak pressure and heat release rate were found to be higher for orange oil compared to diesel fuel operation.     

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.     

Performance and emission study of preheated Jatropha oil on medium capacity diesel engine

Diesel engines have proved its utility in transport, agriculture and power sector. Environmental norms and scared fossil fuel have attracted the attention to switch the energy demand to alternative energy source. Oil derived from Jatropha curcas plant has been considered as a sustainable substitute to diesel fuel. However, use of straight vegetable oil has encountered problem due to its high viscosity. The aim of present work is to reduce the viscosity of oil by heating from exhaust gases before fed to the engine, the study of effects of FIT (fuel inlet temperature) on engine performance and emissions using a dual fuel engine test rig with an appropriately designed shell and tube heat exchanger (with exhaust bypass arrangement). Heat exchanger was operated in such a way that it could give desired FIT. Results show that BTE (brake thermal efficiency) of engine was lower and BSEC (brake specific energy consumption) was higher when the engine was fueled with Jatropha oil as compared to diesel fuel. Increase in fuel inlet temperature resulted in increase of BTE and reduction in BSEC. Emissions of NO_x from Jatropha oil during the experimental range were lower than diesel fuel and it increases with increase in FIT. CO (carbon monoxide), HC (hydrocarbon), CO₂ (carbon dioxide) emissions from Jatropha oil were found higher than diesel fuel. However, with increase in FIT, a downward trend was observed. Thus, by using heat exchanger preheated Jatropha oil can be a good substitute fuel for diesel engine in the near future. Optimal fuel inlet temperature was found to be 80 °C considering the BTE, BSEC and gaseous emissions.     

Use of palm oil-based biofuel in the internal combustion engines: Performance and emissions characteristics

Palm oil (PO) was treated using different methods in order to use and test it as fuel in Compression Ignition (CI) engines. The treatments include PO preheated and preparation of PO/diesel oil blends, using mixtures of PO with waste cooking oil (WCO), which are converted into esters by a transesterification process. The purpose of this study is to evaluate the potential of the palm oil-based biofuels to replace diesel oil in CI engines.Tests were conducted in a single cylinder, four-stroke, air-cooled, direct injection diesel engine (no engine modifications were required). Experiments were initially carried out with diesel oil for providing baseline data. All the tested fuels have a low heating value compared to diesel fuel. A high fraction of PO in diesel fuel decreases the heating value of the blend. The brake thermal efficiency increases for the PO/Diesel blends. HC emissions for all those fuels except for the PO/Diesel blends are found lower, while CO emissions rise for all types of fuels. NO_x emissions are higher at low load, but lower at full load, for the engine fueled with PO and lower both at middle and full load for the engine fueled with the esters.     

低硫燃油在船用中速柴油机上的应用

针对2020年IMO全球船舶限硫令生效,以及国内排放控制区升级,介绍了现行船用燃油的标准和理化特性;使用低硫燃油对发动机的影响及应对措施。开展了低硫燃油和高硫重油的燃油系统平台试验,发现:燃用低硫燃油偶件泄漏量增大,导致高压燃油系统效率下降。基于一船用中速柴油机开展了低硫燃油和高硫重油的发动机台架性能试验,结果显示:燃用低硫燃油较高硫重油在全负荷范围燃油喷射压力降低;高负荷时排温、最高燃烧压力相当,但中低负荷时最高燃烧压力降低,排温和油耗率升高。还介绍了低硫燃油的生产与市场供给、政府监管和油品企业的最新动态。指出远洋船舶中低速柴油机使用低硫油+SCR将成为解决排放问题的优选技术路线之一。     

Comparison between blended mode and fumigation mode on combustion,performance and emissions of a diesel engine fueled with ternary fuel (diesel-biodiesel-ethanol) based on engine speed

According to the literature, there is in lack of a comprehensive study to compare the combustion, performance and emissions of a diesel engine using diesel, biodiesel and ethanol fuels (DBE) in the blended mode and fumigation mode under various engine speeds. This study was conducted to fill this knowledge gap by comparing the effect of blended, fumigation and combined fumigation + blended (F + B) modes on the combustion, performance and emissions of a diesel engine under a constant engine load (50% of full torque) with five engine speeds ranging from 1400 rpm to 2200 rpm. A constant overall fuel composition of 80% diesel, 5% biodiesel and 15% ethanol, by volume % (D80B5E15), was utilized to provide the same fuel for comparing the three fueling modes.According to the average results of five engine speeds, the blended mode has higher peak heat release rate (HRR), ignition delay (ID), brake thermal efficiency (BTE), brake specific nitrogen monoxide (BSNO) and brake specific nitrogen oxides (BSNO_X), but lower duration of combustion (DOC), brake specific fuel consumption (BSFC), brake specific carbon dioxide (BSCO₂), brake specific carbon monoxide (BSCO), brake specific hydrocarbon (BSHC), brake specific nitrogen dioxide (BSNO₂), brake specific particulate matter (BSPM), total number concentration (TNC) and geometric mean diameter (GMD), and similar peak in-cylinder pressure compared to the fumigation mode. In addition, for almost all the parameters, results obtained in the F + B mode are in between those of the blended and fumigation modes. In regard to the effect of engine speed, the results reveal that the increase in engine speed causes reduction in peak in-cylinder pressure, BTE, BSHC, BSNO_X, BSNO and BSNO₂, but increase in peak HRR, ID, DOC, BSFC, BSCO₂, BSPM and TNC, and similar BSCO and GMD for almost all the tested fueling modes. It can be inferred that the blended mode is the suitable fueling mode, compared with the fumigation mode, under the operating conditions investigated in this study.     

Use of HOT EGR for NOx control in a compression ignition engine fuelled with bio-diesel from Jatropha oil

Environmental degradation and depleting oil reserves are matters of great concern round the globe. Developing countries like India depend heavily on oil import. Diesel being the main transport fuel in India, finding a suitable alternative to diesel is an urgent need. Jatropha based bio-diesel (JBD) is a non-edible, renewable fuel suitable for diesel engines and is receiving increasing attention in India because of its potential to generate large-scale employment and relatively low environmental degradation. Diesel engines running on JBD are found to emit higher oxides of nitrogen, NO_x. HOT EGR, a low cost technique of exhaust gas recirculation, is effectively used in this work to overcome this environmental penalty. Practical problems faced while using a COOLED EGR system are avoided with HOT EGR. Results indicated higher nitric oxide (NO) emissions when a single cylinder diesel engine was fuelled with JBD, without EGR. NO emissions were reduced when the engine was operated under HOT EGR levels of 5–25%. However, EGR level was optimized as 15% based on adequate reduction in NO emissions, minimum possible smoke, CO, HC emissions and reasonable brake thermal efficiency. Smoke emissions of JBD in the higher load region were lower than diesel, irrespective of the EGR levels. However, smoke emission was higher in the lower load region. CO and HC emissions were found to be lower for JBD irrespective of EGR levels. Combustion parameters were found to be comparable for both fuels.     

燃油温度对船用柴油机喷雾及燃烧特性影响的仿真研究

以某型船用柴油机为研究对象,通过对不同燃油温度下喷油嘴内部的流动仿真分析,对喷嘴内部的流动和空穴现象进行了研究,得到合理的喷孔出口处油滴的初始状态;通过喷雾和缸内燃烧的耦合计算,分析不同的燃油温度对柴油机燃烧及排放特性的影响规律。研究结果表明:燃油进机温度直接影响燃油喷雾、破碎、蒸发及燃烧过程,对NOx排放影响更为明显;燃油进机温度须作为柴油机燃烧系统开发试验时的试验基准之一。     

Dual fuel mode operation in diesel engines using renewable fuels: Rubber seed oil and coir-pith producer gas

Partial combustion of biomass in the gasifier generates producer gas that can be used as supplementary or sole fuel for internal combustion engines. Dual fuel mode operation using coir-pith derived producer gas and rubber seed oil as pilot fuel was analyzed for various producer gas–air flow ratios and at different load conditions. The engine is experimentally optimized with respect to maximum pilot fuel savings in the dual fuel mode operation. The performance and emission characteristics of the dual fuel engine are compared with that of diesel engine at different load conditions. Specific energy consumption in the dual-fuel mode of operation with oil-coir-pith operation is found to be in the higher side at all load conditions. Exhaust emission was found to be higher in the case of dual fuel mode of operation as compared to neat diesel/oil operation. Engine performance characteristics are inferior in fully renewable fueled engine operation but it suitable for stationary engine application, particularly power generation.     

Experimental study on the role of ethanol on performance emission trade-off and tribological characteristics of a CI engine

An experimental study of engine combustion, performance and emission characteristics using diesel–ethanol blends along with investigation of tribological effects of ethanol on engine oil was done in present work using 1-butanol as emulsifier. Thorough observations of diesel–ethanol miscibility resulted that 25% v/v ethanol is miscible with diesel using only 3% v/v emulsifier. Tribological effects of ethanol on engine oil were investigated by analyzing the engine oil samples through FT-IR (Fourier Transform Infrared Spectroscopy). Overall experimentation re-evaluated the potential of ethanol in reduction of NO_x, Soot and in-cylinder temperature with slight penalty for HC, CO and BSEC prominently at low load. All fuels produced more NO but lesser NO₂ at higher load satisfying Zeldovich mechanism. A comparative trade-off analysis was done in between NHC, Soot and BSEC to reflect the performance and emission characteristics at a time. Trade-off study revealed D78E20B02 (78% diesel 20% ethanol 2% butanol) as optimal blend among all fuels used in present work. FT-IR analysis depicted negligible variation in the compounds in engine oil samples for the specified operational period. Statistical analysis showed larger Coefficient of variation for D78E20B02 blend due to higher absorbance of a particular compound.     

用扩散及准均质混合气压燃的组合燃烧降低柴油机碳烟与NOx排放的研究

在柴油机的一部分工况采用现有的扩散燃烧方式，另一部分工况采用柴油引燃醇燃料均质混合气的组合燃烧方式，利用醇燃料的高汽化潜热和含氧的特性，达到同时降低柴油机碳烟及氮氧化物(NOχ)的目的，并且避免在小负荷燃烧醇燃料带来的高醛类排放问题。在一台4缸水冷直喷式发动机上采用上述组合燃烧法进行试验，从发动机进气管处喷进乙醇形成均质混合气，然后由柴油引燃。由电控装置控制乙醇喷入量及其喷入时刻。试验结果表明，与原机相比，碳烟和NOχ排放分别减少了50％和30％，同时燃料的消耗率也有大幅度降低。     

Hydrogen–ethanol blending as an alternative fuel of spark ignition engines

The performance and pollutant emission of a four-stroke spark ignition engine using hydrogen–ethanol blends as fuel have been studied. The tests were performed using 2, 4, 6, 8, 10 and 12 mass% hydrogen–ethanol blends. Gasoline fuel was used as a basis for comparison. The effect of using different blends of hydrogen–ethanol on engine power, specific fuel consumption, CO and NO_x emission was studied. Operating test results for a range of compression ratio (CR) and equivalent ratio are presented. The results show that the supplemental hydrogen in the ethanol–air mixture improves the combustion process and hence improves the combustion efficiency, expands the range of combustibility of the ethanol fuel, increases the power, reduces the s.f.c., and reduces toxic emissions. The important improvement of hydrogen addition is to reduce the s.f.c. of ethanol engines. Results were compared to those with gasoline fuel at 7 CR and stoichiometric equivalence ratio.     

Experimental study of combustion and emission characteristics of ethanol fuelled port injected homogeneous charge compression ignition (HCCI) combustion engine

The homogeneous charge compression ignition (HCCI) is an alternative combustion concept for in reciprocating engines. The HCCI combustion engine offers significant benefits in terms of its high efficiency and ultra low emissions. In this investigation, port injection technique is used for preparing homogeneous charge. The combustion and emission characteristics of a HCCI engine fuelled with ethanol were investigated on a modified two-cylinder, four-stroke engine. The experiment is conducted with varying intake air temperature (120–150 °C) and at different air–fuel ratios, for which stable HCCI combustion is achieved. In-cylinder pressure, heat release analysis and exhaust emission measurements were employed for combustion diagnostics. In this study, effect of intake air temperature on combustion parameters, thermal efficiency, combustion efficiency and emissions in HCCI combustion engine is analyzed and discussed in detail. The experimental results indicate that the air–fuel ratio and intake air temperature have significant effect on the maximum in-cylinder pressure and its position, gas exchange efficiency, thermal efficiency, combustion efficiency, maximum rate of pressure rise and the heat release rate. Results show that for all stable operation points, NO_x emissions are lower than 10 ppm however HC and CO emissions are higher.     

Performance and emissions characteristics of Jatropha oil (preheated and blends) in a direct injection compression ignition engine

The scarce and rapidly depleting conventional petroleum resources have promoted research for alternative fuels for internal combustion engines. Among various possible options, fuels derived from triglycerides (vegetable oils/animal fats) present promising “greener” substitutes for fossil fuels. Vegetable oils, due to their agricultural origin, are able to reduce net CO₂ emissions to the atmosphere along with import substitution of petroleum products. However, several operational and durability problems of using straight vegetable oils in diesel engines reported in the literature, which are because of their higher viscosity and low volatility compared to mineral diesel fuel.In the present research, experiments were designed to study the effect of reducing Jatropha oil’s viscosity by increasing the fuel temperature (using waste heat of the exhaust gases) and thereby eliminating its effect on combustion and emission characteristics of the engine. Experiments were also conducted using various blends of Jatropha oil with mineral diesel to study the effect of reduced blend viscosity on emissions and performance of diesel engine. A single cylinder, four stroke, constant speed, water cooled, direct injection diesel engine typically used in agricultural sector was used for the experiments. The acquired data were analyzed for various parameters such as thermal efficiency, brake specific fuel consumption (BSFC), smoke opacity, CO₂, CO and HC emissions. While operating the engine on Jatropha oil (preheated and blends), performance and emission parameters were found to be very close to mineral diesel for lower blend concentrations. However, for higher blend concentrations, performance and emissions were observed to be marginally inferior.