Performance,emission and combustion characteristics of CI engine fuelled with diesel and hydrogen

Hydrogen (H₂) is being considered as a primary automotive fuel and as a replacement for conventional fuels. Some of the desirable properties, like high flame velocity, high calorific value motivate us to use hydrogen fuel as a dual fuel mode in diesel engine. In this experiment, hydrogen was inducted in the inlet manifold with intake air. The experiments were conducted on a four stroke, single cylinder, water cooled, direct injection (DI), diesel engine at a speed of 1500 r/min. Hydrogen was stored in a high pressure cylinder and supplied to the inlet manifold through a water-and-air-based flame arrestor. A pressure regulator was used to reduce the cylinder pressure from 140 bar to 2 bar. The hydrogen was inducted with a volume flow rate of 4l pm, 6l pm and 8l pm, respectively by a digital volume flow meter. The engine performance, emission and combustion parameters were analyzed at various flow rates of hydrogen and compared with diesel fuel operation. The brake thermal efficiency (BTE) was increased and brake specific fuel consumption (BSFC) decreased for the hydrogen flow rate of 8l pm as compared to the diesel and lower volume flow rates of hydrogen. The hydrocarbon (HC) and carbon monoxide (CO) were decreased and the oxides of nitrogen (NO_x) increased for higher volume flow rates of hydrogen compared to diesel and lower volume flow rates of hydrogen. The heat release rate and cylinder pressure was increased for higher volume flow rates of hydrogen compared to diesel and lower volume flow rates of hydrogen.     

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。     

Effect of hydroxy gas enrichment on vibration,noise and combustion characteristics of a diesel engine fueled with Foeniculum vulgare oil biodiesel and diesel fuel

Gaseous fuels can be used in diesel engines to improve combustion and obtain more favorable emission. Vibration and noise formation in diesel engines is a rather complex phenomenon which is created during combustion of fuels and leads to a reduction in vehicle comfort. Although there are studies in the literature that examine the noise and vibration of the diesel engine using different biofuels, there is no study that thoroughly examines the effect of combined utilization of Foeniculum vulgare oil biodiesel (FVB) and hydroxy gas (HHO) on vibration, noise and combustion characteristics. Therefore, this study aimed to explore the effects of FVB, a promising biodiesel feedstock, and HHO dual fuel operation on vibration, noise and exhaust emissions of a diesel engine. The vibration, noise and emission data obtained by the use of diesel fuel were taken as a reference and the effects of FVB and HHO mixture utilization on vibration, noise and emission formation were examined. The results show that the total vibration and noise generated by the engine was decreased by the use of FVB. In addition, the utilization of HHO together with biodiesel further reduced the engine vibration and noise according to experimental data. According to exhaust emission formation measurements, the minimum carbon monoxide values were obtained when the engine was fueled with HHO and FVB mixtures. However, CO₂ and NO_X emissions increased with the combination of HHO and FVB usage.     

船用直喷式天然气发动机喷射策略的优化

利用CONVERGE软件基于L23/30DF型船用天然气发动机建立了双天然气喷嘴、双引燃柴油喷嘴的直喷天然气发动机的缸内燃烧过程的CFD计算模型,计算了不同的柴油和天然气喷射时刻和间隔下发动机缸内燃烧和排放过程.结果 表明:引燃柴油的喷射时刻及其与天然气喷射时刻的间隔,对直喷式天然气发动机燃烧和排放性能有重要影响.当喷...     

Influence of cetane number improver on performance and emissions of a common-rail diesel engine fueled with biodiesel-methanol blend

In this paper, the effect of cetane number (CN) improver on performance and emissions, including particulate number concentration and size distribution, of a turbocharged, common-rail diesel engine fueled with biodiesel-methanol were studied. Two volume fractions (0.3% and 0.6%) of CN improver were added to BM30 (30% of methanol in the biodiesel-methanol blend) in the experiment. The results show that, compared with those of biodiesel-methanol blend, the peak value of cylinder pressure increases, the second peak of heat release rate decreases, the start of second heat release are advanced, and the fuel economy and thermal efficiency are improved when CN improver is added to biodiesel-methanol blend. Besides, CO and HC emissions decrease, NO_x emission varies little and smoke emissions increase slightly. Moreover, exhaust particles of BM30 mainly distribute in nano-size range. Furthermore, particle number concentration decreases and peak of size distribution profile shifts toward large size direction.     

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.     

Hydrogen energy share enhancement in a heavy duty diesel engine under RCCI combustion fueled with natural gas and diesel oil

The aim of this study is to enhance hydrogen energy share in a RCCI engine. The engine under consideration is fueled with diesel oil and natural gas enriched with hydrogen or syngas and is set to operate at 9.4 bar gross indicated mean effective pressure (Mid- Load). The syngas used in this study consists of hydrogen and carbon monoxide which are mixed together on a volumetric ratio of 80:20. A fixed amount of diesel oil is injected per cycle into the combustion chamber of the RCCI engine. Based on two different strategies, hydrogen or syngas mixed with exhaust gas recirculation are admitted gradually along with natural gas while ensuring that always the low temperature combustion concept is fulfilled. The RCCI engine operation is simulated through commercial software coupled with chemical kinetics solver. The simulation results show that without any engine diesel knock occurrence, by adding hydrogen to natural gas, the share of hydrogen energy could be increased up to 40.43% while the engine power output is reduced only by about 1%. Also, syngas addition to natural gas causes that the share of hydrogen energy could be increased up to 27.05% while improves the engine power more than 4%. At the same time, by considering two mentioned strategies, the overall hydrocarbon fuel consumption per cycle can be reduced by up to 46.60% and 33.86%, respectively. Moreover, having the gross indicated efficiency of well over 50% and significant reduction in the engine emissions compared to RCCI combustion fueled solely with natural gas and diesel oil are achievable.     

Hydrogen supplemented natural gas effect on a DI diesel engine operating under dual fuel mode with a biodiesel pilot fuel

In order to slow down the continuing environmental deterioration, regulations for pollutant emissions limitations are increasingly rigorous. The development of new alternative fuels for internal combustion engines is a very interesting solution not only to overcome the pollution problem but also because of the petroleum shortage. In this context, the present work investigates the improvement of a DI diesel engine operating at constant speed (1500 rpm) and under dual fuel mode with eucalyptus biodiesel and natural gas (NG) enriched by various H₂ quantities (15, 25 and 30 by v%). The eucalyptus biodiesel quantity injected into the engine cylinder is kept constant, to supply around 10% of the engine nominal power, for all examined engine loads. The engine load is further increased using only the gaseous fuel (NG+H₂), which is introduced with the intake air. The effect of H₂/NG blending ratio on the combustion parameters, performance and pollutant emissions of the engine is investigated and compared with those of pure NG case. An important benefit in terms of brake specific fuel consumption, reaching a decrease of 4–10% with the 25% H₂ blend compared to the pure NG case, is achieved. Concerning the pollutant emissions, NG enrichment with H₂ is an efficient solution to enhance the combustion process and hence reduce carbon monoxide, unburned hydrocarbon and soot emissions at high loads where they are important for pure NG. However for the nitrogen oxide emissions, NG blending with H₂ is attractive only at low and medium loads where their levels are lower than pure NG.     

Investigation on combustion and emission characteristics of hydrogen-enriched dual-fuel engine operated under waste frying oil biodiesel

Using nonedible waste frying oil (WFO) as biodiesel and hydrogen in the mix composition may partly replace significant quantities of diesel fuel and help reduce fossil fuel reliance. The combination of diesel fuel, waste-fired biodiesel, and hydrogen gas can improve the performance, combustion, and emissions of single-fuel and dual-fuel diesel engines. This may lead to a novel alternative fuel mix pattern and modification for diesel engines, which is the research gap. Although there has been some research on waste-fired biodiesel and hydrogen gas-powered dual-fuel engines with the goal of partly replacing fossil fuels to a larger degree, there has been very little progress in this area. As a result, the current research effort focuses on using diesel fuel (100%, 30%, and 60%), waste-fired biodiesel (at 100%, 70%, and 40%), and hydrogen gas as fuel sources (5 and 10 liters per minute [LPM]). According to the current experiment, it was perceived in both dual-fuel and single-fuel modes. Under duel-fuel mode, the engine results for WFOB70D30 + H10 fuel blend had higher 4.2% (brake thermal efficiency [BTE]), 19.72% (oxides of nitrogen [NO_x]), and 9.09% (ignition delay [ID]) with a minimal range of (in-cylinder pressure, MFB, volumetric efficiency and heat release rate [HRR]) and a dropped rate of 4.34% (brake-specific energy consumption [BSEC]), 33.33% (carbon monoxide [CO]), 39.28% (hydrocarbons [HC]), 9.43% (smoke), and 6.97% (combustion duration [CD]) related to diesel fuel at peak load. However, single-fuel powered diesel engines provide minimal performance for the WFOB40D60 fuel blend with (11.32% lower BTE and 2.04% higher BSEC) and minimal rate of combustion (lower cylinder pressure, 2.12% minimal CD, 14.72% higher ID, minimal HRR combustion, volumetric efficiency, and MFB). Emitted fewer emissions (9.09% less CO, 4.87% less HC, 0.92% higher NO_x, and 1.69% more smoke) than diesel fuel at peak load. Therefore, it was concluded that adding 10 LPM of hydrogen gas to the biodiesel under a dual-fuel condition leads to better combustion, better performance, and less pollution than the single-fuel mode of operation.     

柴油引燃天然气发动机燃烧过程的研究

对柴油引燃天然气发动机的着火过程、燃烧过程进行研究,提出了相应的数学模型,并进行了试验验证。着火模型的基本框架仍然采用Shell模型,但考虑到CH4对柴油着火过程的影响,修正了Shell模型。对CH4的均质燃烧过程,以简单的一步表观反应动力学概念的阿伦纽斯(Arrhenius)公式为基础,综合湍流脉动对化学动力学的影响,提出了一个新的燃烧模型。模拟计算借助了KIVA-3软件,修正的Shell模型和燃烧模型作为独立子程序与KIVA-3进行了耦合。研究表明,讨论的模型能够较好模拟柴油引燃天然气发动机的着火和燃烧过程。     

The influence of thermal barrier coating on an LHR engine fueled by soybean biodiesel blended with various additive spectrums: Performance,combustion, and emission analysis

The novelty of this research work deals with green synthesized nanoadditives (5% of graphene, carbon nanotubes, and carbon black), oxygenated additives (5% of n-butanol, n-heptane, and n-pentanol), and then the test fuels are prepared by blending of 20% of soybean biodiesel and 70%, 80%, and 100% of premium diesel. The experimental outcomes revealed that the Nickel Chromium Aluminum (NiCrAl-120 micron), partially stabilized zirconia, and titanium dioxide ceramic composites at about 400 microns achieve the thermal barrier coat of low heat rejection (LHR) engine parts by the air-plasma spray method. Compared with Blend B, green synthesized carbon black (5%), premium diesel (70%), and n-pentanol (5%) mixed soybean biodiesel (20%) fuel (Blend E) tested on the LHR engine achieved 4.90% higher brake thermal efficiency and 25.31% lower brake-specific fuel consumption at peak load owing to the presence of an oxygenated agent (n-pentanol) in the fuel blend, which minimizes carbon deposition. The carbon monoxide, hydrocarbon, NO_x, and smoke emissions were reduced by 25.58%, 29.41%, 5.06%, and 7.75% when compared to Blend B at peak load. Then, the in-cylinder pressure and heat release rate were found to be 4.52% and 8.87% higher for Blend E at peak load compared to Blend B. This was because the mix of oxygenated additive and carbon black bio-based nanofuels made the combustion process go faster. These fuel blends were tested on LHR diesel engines at various load conditions.     

A modified diesel engine for natural gas operation: Performance and emission tests

A diesel engine was modified for natural gas operation to optimize performance using gaseous fuel. A variation of combustion ratios (CR) including 9.0:1, 9.5:1, 10.0:1 and 10.5:1 was utilized to evaluate engine performance and emissions from the same engine over the engine speeds between 1000 and 4000 rpm. Tested engine performance parameters include brake torque, brake power, specific fuel consumption (SFC) and brake thermal efficiency. Emissions tests recorded total hydrocarbon (THC), nitrogen oxides (NO_x) and carbon monoxide (CO). The results showed that a CR of 9.5:1 had the highest thermal efficiency and the lowest SFC while a CR of 10:1 showed a high torque at low speed. THC emissions were directly proportional to the CR. NO_x emissions increased with increasing CR and then declined after a CR of 10:1.     

An experimental study of combustion and emissions in a spark-ignition engine fueled with coal-bed gas

Coal-bed gas has been considered an attractive alternative fuel for internal combustion engines due to its abundant source and low emissions. In the present study, a combustion system with a swirl chamber has been developed for a spark-ignition engine using coal-bed gas. Detailed experiments have been carried out to investigate the combustion and emission characteristics of the engine operating with three different grades of coal-bed gas. The results have shown that this combustion system allows satisfactory operation of the engine with a wide range of methane content in the supplied coal-bed gas. For all tested conditions, the CO emission has a maximum value of 0.062%, and the HC emission is less than 380 ppm. The NO emission increases with the engine load but is less than 1800 ppm, demonstrating a great advantage of coal-bed gas as a relatively clean engine fuel.     

Effect of hydrogen addition on RCCI combustion of a heavy duty diesel engine fueled with landfill gas and diesel oil

The aim of this study is to investigate the effects of hydrogen addition on RCCI combustion of an engine running on landfill gas and diesel oil. A single cylinder heavy– duty diesel engine is set in operation at 9.4 bar IMEP. A certain amount of diesel fuel per cycle is fed into the engine and hydrogen is added to landfill gas while keeping fixed fuel energy content. The developed simulation results confirm that hydrogen addition which is the most environmental friendly fuel causes the fuel consumption per any cycle to reduce. Also, the peak pressure is increased while the engine load is reduced up to 4%. Landfill gas which is enriched with hydrogen improves the rate of methane dissociation and reduces the combustion duration at the same time the engine operation would not be exposed to diesel knock. Moreover, hydrogen addition to landfill gas would reduce engine emissions considerably.     

Experimental study on thermal efficiency and emission characteristics of a lean burn hydrogen enriched natural gas engine

In order to analyze the effect of hydrogen addition on natural gas (NG) engine's thermal efficiency and emission, an experimental research was conducted on a spark ignition NG engine using variable composition hydrogen/CNG mixtures (HCNG). The results showed that hydrogen enrichment could significantly extend the lean operation limit, improve the engine's lean burn ability, and decrease burn duration. However, nitrogen oxides (NO_x)$({\text{NO}}_x)$ were found to increase with hydrogen addition if spark timing was not optimized according to hydrogen's high burn speed. Also found when spark timing was set at constant was that hydrogen addition actually increases heat transfer out of the cylinder due to smaller quenching distance and higher combustion temperature, thus is not good to improve thermal efficiency if combined with the effect of non-ideal spark timing. But if spark timing was retarded to MBT, taking advantage of hydrogen's high burn speed, _NOx${\mathrm{NO}}_x$ emissions exhibited no obvious increase after hydrogen addition and engine thermal efficiency increased with the increase of hydrogen fraction. Unburned hydrocarbon always decreased with the increase of hydrogen fraction.     

Performance and emission evaluation of a diesel engine fueled with methyl esters of rubber seed oil

Recent concerns over the environment, increasing fuel prices and scarcity of its supply have promoted the interest in development of the alternative sources for petroleum fuels. At present, biodiesel is commercially produced from the refined edible vegetable oils such as sunflower oil, palm oil and soybean oil, etc. by alkaline-catalyzed esterification process. This process is not suitable for production of biodiesel from many unrefined non-edible vegetable oils because of their high acid value. Hence, a two-step esterification method is developed to produce biodiesel from high FFA vegetable oils. The biodiesel production method consists of acid-catalyzed pretreatment followed by an alkaline-catalyzed transesterification. The important properties of methyl esters of rubber seed oil are compared with other esters and diesel. Pure rubber seed oil, diesel and biodiesel are used as fuels in the compression ignition engine and the performance and emission characteristics of the engine are analyzed. The lower blends of biodiesel increase the brake thermal efficiency and reduce the fuel consumption. The exhaust gas emissions are reduced with increase in biodiesel concentration. The experimental results proved that the use of biodiesel (produced from unrefined rubber seed oil) in compression ignition engines is a viable alternative to diesel.     

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.     

Influence of biodiesel on engine combustion and emission characteristics

This paper discusses the influence of biodiesel on the engine combustion characteristics. The considered fuel is neat biodiesel from rapeseed oil. The considered engine is a bus diesel engine with injection M system. The engine characteristics are obtained by experiments and numerical simulation. The results obtained with biodiesel are compared to those obtained with mineral diesel under various operating regimes. In this way, the influences of biodiesel usage on the injection pressure, injection timing, ignition delay, in-cylinder gas pressure and temperature, heat release rate, exhaust gas temperatures, harmful emissions, specific fuel consumption, and on engine power are analyzed. Furthermore, the relationships among fuel properties, injection and combustion characteristics, harmful emissions, and other engine performance are determined. Special attention is given to possible explanations of higher NO_x emission in spite of lower in-cylinder gas temperature.     

Emission analysis of different blends of karanja biodiesel with producer gas in a twin cylinder diesel engine in dual fuel mode

The present study demonstrates the emission analysis of different blends of Karanja biodiesel and diesel with producer gas in dual fuel mode using a twin cylinder diesel engine for two cases of operations. In case 1, a test is carried out using the above test fuels both in single mode and dual fuel mode operation with a constant gas flow rate of 21.49 Kg/h under different load conditions. Similarly, in case 2, a test is performed at a constant load of 10 kW under different gas flow rates using the same test fuels in the dual fuel mode only. The study reveals that all blended fuels show better emissions compared to diesel in both cases of operations. Dual fuel mode operation of all tested fuels shows lower smoke and oxide of nitrogen emissions compared to their single mode operation under all load conditions, whereas other emission parameters are found to be on the higher side.     

不同简化机理对高压直喷天然气船机燃烧和排放影响研究

基于三维CFD仿真软件模拟了高压直喷天然气船机的燃烧过程,探讨了四种不同简化程度机理对燃烧和排放的影响规律。结果表明：四种机理均能很好的预测高压直喷天然气船机在不同喷射时刻下的缸压和放热率。四个机理预测的燃烧相位和最高爆发压力随喷射时刻提前或推迟变化趋势一致;预测的不同燃烧相位的温度、当量比和NO_x分布存在较小差异。但35步机理和27步机理预测的碳烟排放比334步机理和250步机理高。整体上,受船机大尺度计算资源高限制,耦合简化的35步和27步机理的CFD模型预测的燃烧参数最大误差小于4.3%,预测的NO_x排放最大误差小于12.0%,能够满足船机工程开发需求。