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1.
《International Journal of Hydrogen Energy》2022,47(62):25913-25928
The high flammability of hydrogen gas gives it a steady flow without throttling in engines while operating. Such engines also include different induction/injection methods. Hydrogen fuels are encouraging fuel for applications of diesel engines in dual fuel mode operation. Engines operating with dual fuel can replace pilot injection of liquid fuel with gaseous fuels, significantly being eco-friendly. Lower particulate matter (PM) and nitrogen oxides (NOx) emissions are the significant advantages of operating with dual fuel.Consequently, fuels used in the present work are renewable and can generate power for different applications. Hydrogen being gaseous fuel acts as an alternative and shows fascinating use along with diesel to operate the engines with lower emissions. Such engines can also be operated either by injection or induction on compression of gaseous fuels for combustion by initiating with the pilot amount of biodiesel. Present work highlights the experimental investigation conducted on dual fuel mode operation of diesel engine using Neem Oil Methyl Ester (NeOME) and producer gas with enriched hydrogen gas combination. Experiments were performed at four different manifold hydrogen gas injection timings of TDC, 5°aTDC, 10°aTDC and 15°aTDC and three injection durations of 30°CA, 60°CA, and 90°CA. Compared to baseline operation, improvement in engine performance was evaluated in combustion and its emission characteristics. Current experimental investigations revealed that the 10°aTDC hydrogen manifold injection with 60°CA injection duration showed better performance. The BTE of diesel + PG and NeOME + PG operation was found to be 28% and 23%, respectively, and the emissions level were reduced to 25.4%, 14.6%, 54.6%, and 26.8% for CO, HC, smoke, and NOx, respectively. 相似文献
2.
The internal combustion engines have already become an indispensable and integral part of our present day life style, particularly in the transportation and agricultural sectors [Nagalingam B. Properties of hydrogen. In: Proceedings of the summer school of hydrogen energy, IIT Madras, 1984]. Unfortunately the survival of these engines has, of late, been threatened due to the problems of fuel crisis and environmental pollution. Therefore, to sustain the present growth rate of civilization, a nondepletable, clean fuel must be expeditiously sought. Hydrogen exactly caters to the specified needs. Hydrogen, even though “renewable” and “clean burning”, does give rise to some undesirable combustion problems in an engine operation, such as backfire, pre-ignition, knocking and rapid rate of pressure rise [Srinivasa Rao P. Utilization of hydrogen in a dual fueled engine. In: Proceedings of the summer school of hydrogen energy, IIT Madras, 1984; Siebers DL. Hydrogen combustion under diesel engine conditions. Hydrogen Energy 1998;23:363–71]. The present investigation compares the performance and emission characteristics of a DI diesel engine with gaseous hydrogen as a fuel inducted by means of carburation technique and timed port injection technique (TPI) along with diesel as a source of ignition [Swain N, Design and testing of dedicated hydrogen-fueled engine. SAE 961077, 1996]. In the present study the specific energy consumption, NOx emission and the exhaust gas temperature increased by 6%, 8% and 14%, respectively, and brake thermal efficiency and smoke level reduced by 5% and 8%, respectively, using carburation technique compared to baseline diesel. But in the TPI technique, the specific energy consumption, exhaust gas temperature and smoke level reduced by 15%, 45% and 18%, respectively. The brake thermal efficiency and NOx increased by 17% and 34%, respectively, compared to baseline diesel. The emissions such as HC, CO, and CO2 is very low in both carburation and TPI techniques compared baseline diesel. 相似文献
3.
Fast depletion of fossil fuels is demanding an urgent need to carry out research work to find out the viable alternative fuels for meeting sustainable energy demand with minimum environmental impact. In the future, our energy systems will need to be renewable and sustainable, efficient and cost-effective, convenient and safe. The technology for producing hydrogen from a variety of resources, including renewable, is evolving and that will make hydrogen energy system as cost-effective. Hydrogen safety concerns are not the cause for fear but they simply are different than those we are accustomed to with gasoline, diesel and other fossil fuels. For the time being full substitution of diesel with hydrogen is not convenient but use of hydrogen in a diesel engine in dual fuel mode is possible. So Hydrogen has been proposed as the perfect fuel for this future energy system. The experiment is conducted using diesel–hydrogen blend. A timed manifold induction system which is electronically controlled has been developed to deliver hydrogen on to the intake manifold. The solenoid valve is activated by the new technique of taking signal from the rocker arm of the engine instead of cam actuation mechanism. In the present investigation hydrogen-enriched air has been used in a diesel engine with hydrogen flow rate at 0.15 kg/h. As diesel is substituted and hydrogen is inducted, the NOx emission is increased. In order to reduce NOx emission an EGR system has been developed. In the EGR system a lightweight EGR cooler has been used instead of bulky heat exchanger. In this experiment performance parameters such as brake thermal efficiency, volumetric efficiency, BSEC are determined and emissions such as oxides of nitrogen, carbon dioxide, carbon monoxide, hydrocarbon, smoke and exhaust gas temperature are measured. Dual fuel operation with hydrogen induction coupled with exhaust gas recirculation results in lowered emission level and improved performance level compared to the case of neat diesel operation. 相似文献
4.
《能源学会志》2020,93(1):129-151
There are some challenges about NOX emissions exhausted from diesel engines fueled with biodiesel. Due to increasingly stringent emission regulations, the different methods such as varying the engine operating parameters, treatment with antioxidant additive and blending fuels have been adapted to reduce emissions of biodiesel combustion. One of the effective methods is the combustion of dual or blending fuels. Various fuels such as gasoline, hydrogen, natural gas, biogas, different types of alcohols and also fuel additives have been used to reduce biodiesel disadvantages. This study reviews the potential of the different fuels as an additive in biodiesel fuel in correspond to reduce NOX emissions. The general reduction of NOX has been observed with the presence of gasoline, biogas and alcohols in biodiesel blends. The reduction of NOX in biodiesel-hydrogen, biodiesel-diesel or biodiesel–CNG combustion has not been observed through all engine conditions. Moreover the retarding injection timing, the lower injection pressure, EGR higher than 30% can result in the reduced NOX emissions. However it seems the decrease in NOX emissions can be achieved by the use of most fuels in blending with biodiesel under all engine operating conditions, if only the proper injection parameters and blending proportions of fuels are set. 相似文献
5.
Stringent emission norms and rapid depletion of petroleum resources have resulted in a continuous effort to search for alternative fuels. Hydrogen is one of the best alternatives for conventional fuels. Hydrogen has both the benefits and limitation to be used as a fuel in an automotive engine system. In the present investigation, hydrogen was injected into the intake manifold by using a hydrogen gas injector and diesel was introduced in the conventional, mode which also acts as an ignition source for hydrogen combustion. The flow rate of hydrogen was set at 5.5 l min?1 at all the load conditions. The injection timing was kept constant at top dead center (TDC) and injection duration was adjusted to find the optimized injection condition. Experiments were conducted on a single cylinder, four stroke, water‐cooled, direct injection diesel engine coupled to an electrical generator. At 75% load the maximum brake thermal efficiency for hydrogen operation at injection timing of TDC and with injection duration of 30°CA is 25.66% compared with 21.59% for diesel. The oxides of nitrogen (NOX) emission are 21.7 g kWh?1 for hydrogen compared with diesel of 17.9 g k Wh?1. Smoke emissions reduced to 1 Bosch smoke number (BSN) in hydrogen compared with diesel of 2.2 BSN. Hydrogen operation in the dual fuel mode with diesel exhibits a better performance and reduction in emissions compared with diesel in the entire load spectra. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
6.
Over the past two decades there has been a considerable effort to develop and introduce alternative transportation fuels to replace conventional fuels, gasoline and diesel. Environmental issues are the principal driving forces behind this effort. To date the bulk of research has focused on the carbon-based fuels such as reformulated gasoline, methanol and natural gas. One alternative fuel to carbon-based fuels is hydrogen which is considered to be low polluting fuel. In the present experimental investigation hydrogen was injected into the intake manifold by using an injector. Using an electronic control unit (ECU) the injection timing and the duration were controlled. From the results it is observed that the optimum injection timing is at gas exchange top dead center (GTDC). The efficiency improved by about 15% with an increase in NOX emission by 3% compared to diesel. The smoke emission decreased by almost 100%. A net reduction in carbon emissions was also noticed due to the use of hydrogen. By adopting manifold injection technique the hydrogen–diesel dual fuel engine operates smoothly with a significant improvement in performance and reduction in emissions. 相似文献
7.
《International Journal of Hydrogen Energy》2022,47(26):13157-13167
The impact of dual fuel (diesel/hydrogen) on different performance aspects of CRDI diesel engines is investigated in this study. Amongst the fuel alternatives for IC (internal combustion) engines, the research described in this study recommended hydrogen as the least polluting and renewable in the long term. A CNG-LPG injector feeds hydrogen into the intake manifold, while diesel injectors pump pilot diesel to a DI engine adapted to hydrogen and diesel (dual-fuel mode). By maintaining 5.2 KW of consistent IP (Indicated Power) and engine speed at 1500 ± 10 rotations per minute (RPM), the hydrogen energy was varied in the dual fuel at 0% (100% diesel), 6%, 12%, 18% and 24%. With the increase in H2 energy proportion, a decrease (5.2% decrease at 24% HES) in the BSEC (brake specific energy consumption) and the engine's BTE (brake thermal efficiency) is improved (7.85% increase at 24% HES). When emissions are considered, indicated NOx increased (3.42%) while indicated CO2 (3.61%), CO (2.84%), and smoke (4.85%) decreased with an increase in the proportion of hydrogen. Along with this, it was noted that the peak HRR (heat release rate) of 69.8 J/deg and in-cylinder pressure of 80.8 bar which increased significantly with the increase in hydrogen rate. 相似文献
8.
Chandra Bhushan Kumar D.B. Lata Dhaneshwar Mahto 《International Journal of Hydrogen Energy》2021,46(14):9595-9612
Today, the world faces a number of challenges on global level. The optimum replacement for fossil fuels is one of these challenges. Hydrogen in the past has been and continues to be used by numerous researchers in diesel engines. However, high NOx emissions and low replacement of hydrogen fuel are the concern with many researchers. In the present study, di-tert butyl peroxide (DTBP) has been used as an additive in diesel fuel, to investigate the performance and exhaust emissions of the diesel engine working on dual fuel mode by using hydrogen as secondary fuel. At low, medium and high load conditions, the maximum increase in brake thermal efficiency was observed to be 87.50%, 14.68% and 5.89% respectively for 1%, 3% and 5% of additive (DTBP) by 40% of hydrogen fuel substitution, as compared to diesel fuel operation. Moreover, by addition of 4% di-tert butyl peroxide (DTBP) in diesel engine working on dual fuel mode showed 33.82%, 10.27% and 29.27% reduction in NOx emission at low, medium and high load conditions respectively at 40% hydrogen substitution, as compared to dual fuel operation using hydrogen as secondary fuel without additives. By addition of 5% additive (DTBP) at 69% load condition and 40% hydrogen substitution, reduces CO emissions by 38.66% as compared to dual fuel operation, using hydrogen as secondary fuel. 相似文献
9.
Midhat Talibi Paul Hellier Robert Morgan Chris Lenartowicz Nicos Ladommatos 《International Journal of Hydrogen Energy》2018,43(18):9046-9058
The co-combustion of diesel fuel with H2 presents a promising route to reduce the adverse effects of diesel engine exhaust pollutants on the environment and human health. This paper presents the results of H2-diesel co-combustion experiments carried out on two different research facilities, a light duty and a heavy duty diesel engine. For both engines, H2 was supplied to the engine intake manifold and aspirated with the intake air. H2 concentrations of up to 20% vol/vol and 8% vol/vol were tested in the light duty and heavy duty engines respectively. Exhaust gas circulation (EGR) was also utilised for some of the tests to control exhaust NOx emissions.The results showed NOx emissions increase with increasing H2 in the case of the light duty engine, however, in contrast, for the heavy duty engine NOx emissions were stable/reduced slightly with H2, attributable to lower in-cylinder gas temperatures during diffusion-controlled combustion. CO and particulate emissions were observed to reduce as the intake H2 was increased. For the light duty, H2 was observed to auto-ignite intermittently before diesel fuel injection had started, when the intake H2 concentration was 20% vol/vol. A similar effect was observed in the heavy duty engine at just over 8% H2 concentration. 相似文献
10.
Diesel engines are the most trusted power sources in the transportation industry. They intake air and emit, among others, the pollutants NOX and particulate matter. Continuous efforts and tests have tried to reduce fuel consumption and exhaust emissions of internal combustion engines. Alternative fuels are key to meeting upcoming stringent emission norms. We study hydrogen as an air-enrichment medium with diesel as an ignition source in a stationary diesel engine system to improve engine performance and reduce emissions. Stationary engines can be operated with less fuel than neat diesel operations, resulting in lower smoke levels and particulate emissions. Hydrogen (H2)-enriched air systems in diesel engines enable the realization of higher brake thermal efficiency, resulting in lower specific energy consumption (SEC). NOX emissions are reduced from 2762 to 515 ppm with 90% hydrogen enrichment at 70% engine load. At full load, NOX emission marginally increases compared to diesel operation, while both smoke and particulate matter are reduced by about 50%. The brake thermal efficiency increases from 22.78% to 27.9% with 30% hydrogen enrichment. Thus, using hydrogen-enriched air in a diesel engine produces less pollution and better performance. 相似文献
11.
Development of variable timing fuel injection cam for effective abatement of diesel engine emissions
Fossil fuel run diesel engines are being favored in light, medium and heavy duty applications as they exhibit higher fuel conversion efficiencies. Direct injection diesels are still facing challenges to obtain trade-off between oxides of nitrogen and particulate emissions. There are sophisticated strategies such as common rail direct injection, particulate filters with associated sensors and actuators but limited to expensive comfort vehicles. In the present experimental study, a mechanically operated simple component, variable timing fuel injection cam, is designed for a 510 cc automotive type naturally aspirated, water-cooled, direct injection diesel engine. Modifications in the fuel injection cam and gear train are carried out to suit the existing engine configuration. Variable speed tests are carried out for testing the efficacy of component on both engine and chassis dynamometers for performance and emissions. It is observed that the engine which is already retarded could further be retarded with variable timing fuel injection cam. Significant reductions in NOx and smoke emission levels are achieved. Combined effect of VIC with 7% EGR could reduce CO by about 88%, HC + NOx by 37% and PM emissions by 90%. The Engine incorporated with the designed component and EGR, successfully satisfied the existing emission norms with improved power and specific fuel consumption. 相似文献
12.
《International Journal of Hydrogen Energy》2020,45(33):16874-16889
The prime intention of this work is to provide a maximum replacement for diesel using hydrogen in a common rail direct injection equipped diesel engine. The experiment was conducted upto 5.2 kW brake power constant speed water-cooled engine. In the combustion chamber, diesel fuel was injected at a crank angle of 23⁰ bTDC, making it an ignitor for the premixed mixture of hydrogen and air. Hydrogen is injected at 6 different proportions ranging from 6 to 36 liter per min (LPM). The air and hydrogen gas were mixed homogeneously using the timed manifold injection technique, which was controlled through the in-house PC based data acquisition (DAQ) program developed on data factory. The electronic control unit helps to induct the hydrogen for a period of 211⁰ CA during the suction stroke. Performance, emission and combustion studies were made with the different levels of hydrogen injection, which proves that the 30 LPM of hydrogen provide the best results. Further, 30.65% improvement was achieved in brake thermal efficiency with 23.48% decreased brake specific energy consumption. This also helped to reduce the harmful emissions like CO, CO2, UHC and smoke by 22.3%, 14%, 32.74% and 43.86%, respectively. However, oxides of nitrogen emission level was increased by 7.3% compared to that of the diesel fuel at its maximum power output setting. The duration of the combustion also reduced due to the higher flame speed character of hydrogen. Thus, the overall results conclude that the addition of hydrogen improved the performance factors and reduced all the emission values of the common rail direct injection diesel engine at an optimum level of 30 LPM. 相似文献
13.
《International Journal of Hydrogen Energy》2020,45(11):7098-7118
During the past decades, the diesel engine has been through times of upheaval, boom and bust. At the beginning of the century, almost 50% of the new vehicle registrations in the European market were diesel-powered. However, the news of deadly diesel NOx emissions supported by the diesel emission scandals caused a shock to the diesel engine market, and the sustainability of the diesel engine is currently in dispute.Recently major automotive manufacturers announced the development of diesel-powered vehicles with negligible NOx emissions. Moreover, the NOx emissions production is of lower concern for heavy-duty, marine or power generations applications where the implementation of advanced aftertreatment systems is feasible. However, despite the tackle of NOx emissions, the decarbonisation of the automotive, marine and power generation markets is mandatory for meeting greenhouse gas emissions targets and limiting global warming.The decarbonisation of the diesel engine can be achieved by the implementation of a carbon-free fuel such as ammonia. This paper provides a detailed overview of ammonia as a fuel for compression ignition engines. Ammonia can be combusted with diesel or any other lower autoignition temperature fuel in dual-fuel mode and lead to a significant reduction of carbon-based emissions. The development of advanced injection strategies can contribute to enhanced performance and overall emissions improvement. However, ammonia dual-fuel combustion currently suffers from relatively high unburned ammonia and NOx emissions because of the fuel-bound nitrogen. Therefore, the implementation of aftertreatment systems is required. Hence, ammonia as a compression ignition fuel can be currently seen as a feasible solution only for marine, power generation and possibly heavy-duty applications where no significant space constraints exist. 相似文献
14.
Diesel engines are indispensable in daily life. However, the limited supply of petroleum fuels and the stringent regulations on such fuels are forcing researchers to study the use of hydrogen as a fuel. In this study, a diesel engine is operated using hydrogen–diesel dual fuel, where hydrogen is introduced into the intake manifold using an LPG-CNG injector and pilot diesel is injected using diesel injectors. The energy contents of the total fuel, 0%, 16%, 36% and 46% hydrogen (the 0% hydrogen energy fraction represents neat diesel fuel), were tested at 1300 rpm of constant engine speed and 5.1 kW of constant indicated power. According to test results, the indicated thermal efficiency of the engine decreases and the isfc increases with an increasing hydrogen energy fraction. Additionally, indicated specific CO, CO2 and smoke emissions decrease with an increasing percentage of hydrogen fuel. However, indicated specific NOx emissions do not change at the 16% hydrogen energy fraction, in other words, with an increase in the hydrogen amount (36% and 46% hydrogen energy fraction of total fuel), a dramatic increase (58.8% and 159.7%, respectively) is observed. Additionally, the peak in-cylinder pressure and the peak heat release rate values increase with the increasing hydrogen rate. 相似文献
15.
《International Journal of Hydrogen Energy》2023,48(51):19713-19732
The use of hydrogen in internal combustion engines is pointed out as an alternative to reduce greenhouse gas emissions. In applications that require high levels of torque and low engine speeds, compression ignition (CI) engines are more appropriate. However, because of the high auto-ignition temperature of hydrogen, its use in these engine types is more suitable when the dual-fuel concept is applied. This study comprehensively investigates, through experimental techniques, the use of hydrogen port-injection in a four-stroke single-cylinder CI engine operating with the renewable diesel-like fuels hydrotreated vegetable oil (HVO) and farnesane, in comparison to fossil diesel dual-fuel operation. In this sense, the present work aims to fill a gap in the literature by performing a novel analysis of dual-fuel operation with hydrogen, considering different substitution fractions, and using groundbreaking biofuels, such as HVO and farnesane. The results showed that in-cylinder pressure and temperature were increased with H2 enrichment for every pilot fuel, but green diesel fuels presented lower values than those for diesel operation. Furthermore, hydrogen port injection slightly delayed the start of combustion and increased the ignition delay, but a reduction in both premixed and diffusion combustion duration was observed. Reductions in PM, CO, and CO2 emissions were reported during H2 addition for every pilot fuel, while increased NOx was observed. Despite this increase, both HVO and farnesane decreased the emissions of this pollutant in single and dual-fuel operations, compared with fossil diesel. In addition, both renewable diesel fuels presented higher BTE than diesel for every studied H2 mass flow. 相似文献
16.
Exhaust gas recirculation, EGR, is one of the most effective means of reducing NOx emissions from IC engines and is widely used in order to meet the emission standards. In the present work, experimental investigation has been carried out to study the NOx reduction characteristics by exhaust gas recirculation in a dual fueled engine using hydrogen and diesel. A single cylinder diesel engine was converted to operate on hydrogen-diesel dual fuel mode. Hydrogen was injected in intake port and diesel was injected directly inside the cylinder. The injection timing and injection duration of hydrogen were optimized initially based on the performance and emissions. It was observed that start of injection at 5° before gas exchange top dead center (BGTDC) and injection duration of 30° crank angle gives the best results. The flow rate of hydrogen was optimized as 7.5 lpm for the best start of injection and injection duration of hydrogen. Cold exhaust gas recirculation technique was adopted for the optimized injection parameter of hydrogen and flow rate. Maximum quantity of exhaust gases recycled during the test was 25% beyond this the combustion was not stable resulting in increase in smoke. 相似文献
17.
Gregory K. Lilik Hedan Zhang José Martin Herreros Daniel C. Haworth André L. Boehman 《International Journal of Hydrogen Energy》2010
Hydrogen assisted diesel combustion was investigated on a DDC/VM Motori 2.5L, 4-cylinder, turbocharged, common rail, direct injection light-duty diesel engine, with a focus on exhaust emissions. Hydrogen was substituted for diesel fuel on an energy basis of 0%, 2.5%, 5%, 7.5%, 10% and 15% by aspiration of hydrogen into the engine's intake air. Four speed and load conditions were investigated (1800 rpm at 25% and 75% of maximum output and 3600 rpm at 25% and 75% of maximum output). A significant retarding of injection timing by the engine's electronic control unit (ECU) was observed during the increased aspiration of hydrogen. The retarding of injection timing resulted in significant NOX emission reductions, however, the same emission reductions were achieved without aspirated hydrogen by manually retarding the injection timing. Subsequently, hydrogen assisted diesel combustion was examined, with the pilot and main injection timings locked, to study the effects caused directly by hydrogen addition. Hydrogen assisted diesel combustion resulted in a modest increase of NOX emissions and a shift in NO/NO2 ratio in which NO emissions decreased and NO2 emissions increased, with NO2 becoming the dominant NOX component in some combustion modes. Computational fluid dynamics analysis (CFD) of the hydrogen assisted diesel combustion process captured this trend and reproduced the experimentally observed trends of hydrogen's effect on the composition of NOX for some operating conditions. A model that explicitly accounts for turbulence–chemistry interactions using a transported probability density function (PDF) method was better able to reproduce the experimental trends, compared to a model that ignores the influence of turbulent fluctuations on mean chemical production rates, although the importance of the fluctuations is not as strong as has been reported in some other recent modeling studies. The CFD results confirm that temperature changes alone are not sufficient to explain the observed reduction in NO and increase in NO2 with increasing H2. The CFD results are consistent with the hypothesis that in-cylinder HO2 levels increase with increasing hydrogen, and that the increase in HO2 enhances the conversion of NO to NO2. Increased aspiration of hydrogen resulted in PM, and HC emissions which were combustion mode dependent. Predominantly, CO and CO2 decreased with the increase of hydrogen. The aspiration of hydrogen into the engine modestly decreased fuel economy due to reduced volumetric efficiency from the displacement of air in the cylinder by hydrogen. 相似文献
18.
Numerous studies have demonstrated the advantages of hydrogen as a fuel for Otto Cycle engines due to high thermal efficiency and low exhaust pollutant levels. Characteristic of hydrogen engine operation using premixed intake charge formation is a problem of pre-ignition resulting in an intake manifold “backfire”. Additional problems include high NOx production when using certain equivalence ratios and power output degradation due to low fuel energy/volume density.Techniques for direct and port fuel injection are discussed as means for overcoming these problems. Emphasis is placed on the need for total engine control, integrating control of fuel injection, ignition timing, intake air throttling, and vehicle subsystems within a central electronic unit. An electronically actuated fuel injection valve and a prototype electronic control system are developed. These are applied in port and direct injection system geometries, and evaluated in engine testing. System effectiveness and feasibility are discussed. 相似文献
19.
Diesel fuelled engines emit higher levels of carbon dioxide and other harmful air pollutants (such as noxious gases and particulates) per litre of fuel than gasoline engines. This fact, combined with the recent diesel emission scandal and the rumours of more widespread cheating by automotive manufacturers have initiated a long discussion about the future and sustainability of diesel engines.Improving the compression ignition engine is a direct way of going green. Reducing the harmful emissions can be achieved by future developments in the engine technology but also the implementation of alternative fuels. Hydrogen is a renewable, high-efficient and clean fuel that can potentially save the future of diesel-type engines. The evolution of high-efficiency renewable hydrogen production methods is the most important path for the start of a new hydrogen era for the compression ignition engine that can improve its sustainability and maximum efficiency.This paper provides a detailed overview of hydrogen as a fuel for compression ignition engines. A comprehensive review of the past and recent research activities on the topic is documented. The review focuses on the in-cylinder combustion of hydrogen either as a primary fuel or in dual fuel operation. The effects of injection strategies, compression ratio and exhaust gas recirculation on the combustion and emission characteristics of the hydrogen fuelled engine are fully analysed. The main limitations, challenges and perspectives are presented. 相似文献
20.
Over the past two decades considerable efforts have been undertaken to develop and introduce new alternative fuels for the conventional gasoline and diesel. Many alternative fuels, both liquid and gaseous, have been experimented and some have even been commercialized such as ethanol, natural gas, etc. Hydrogen has been considered as an excellent fuel to replace the petroleum‐based fuels due to its clean burning characteristics. In the present experimental investigation, hydrogen was injected in the intake manifold and diesel fuel was injected inside the engine cylinder in the conventional manner. Hydrogen injection parameters such as injection timing, injection duration and quantity of hydrogen injected were optimized based on the performance and emission characteristics. Exhaust gas recirculation (EGR) technique was adopted to reduce the oxides of nitrogen emission. From the results it was observed that for hydrogen diesel dual fuel (DF) engine, the optimal operating parameters for hydrogen injection were start of injection at gas exchange top dead centre with injection duration of 30° crank angle with the hydrogen flow rate of 7.5 litres per minute (lpm). With EGR the optimized condition was found to be 20% for the entire load. The brake thermal efficiency with 20% EGR increases by 16% at 75% load as compared with diesel, while at full load it reduces by 8% due to the recirculation of exhaust gases that results in a reduction of intake oxygen concentration compared with part load. NOX emission decreases by five and half times, while other emissions increase by 1.4 times as compared with DF engine. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献