Direct injection of hydrogen main fuel and diesel pilot fuel in a retrofitted single-cylinder compression ignition engine

Up to 90% hydrogen energy fraction was achieved in a hydrogen diesel dual-fuel direct injection (H2DDI) light-duty single-cylinder compression ignition engine. An automotive-size inline single-cylinder diesel engine was modified to install an additional hydrogen direct injector. The engine was operated at a constant speed of 2000 revolutions per minute and fixed combustion phasing of ?10 crank angle degrees before top dead centre (°CA bTDC) while evaluating the power output, efficiency, combustion and engine-out emissions. A parametric study was conducted at an intermediate load with 20–90% hydrogen energy fraction and 180-0 °CA bTDC injection timing. High indicated mean effective pressure (IMEP) of up to 943 kPa and 57.2% indicated efficiency was achieved at 90% hydrogen energy fraction, at the expense of NO_x emissions. The hydrogen injection timing directly controls the mixture condition and combustion mode. Early hydrogen injection timings exhibited premixed combustion behaviour while late injection timings produced mixing-controlled combustion, with an intermediate point reached at 40 °CA bTDC hydrogen injection timing. At 90% hydrogen energy fraction, the earlier injection timing leads to higher IMEP/efficiency but the NO_x increase is inevitable due to enhanced premixed combustion. To keep the NO_x increase minimal and achieve the same combustion phasing of a diesel baseline, the 40 °CA bTDC hydrogen injection timing shows the best performance at which 85.9% CO₂ reduction and 13.3% IMEP/efficiency increase are achieved.     

Experimental investigations on the effect of fuel injection parameters on diesel engine fuelled with biodiesel blend in diesel with hydrogen enrichment

Fuel injection pressure and injection timing are two extensive injection parameters that affect engine performance, combustion, and emissions. This study aims to improve the performance, combustion, and emissions characteristics of a diesel engine by using karanja biodiesel with a flow rate of 10 L per minute (lpm) of enriched hydrogen. In addition, the research mainly focused on the use of biodiesel with hydrogen as an alternative to diesel fuel, which is in rapidly declining demand. The experiments were carried out at a constant speed of 1500 rpm on a single-cylinder, four-stroke, direct injection diesel engine. The experiments are carried out with variable fuel injection pressure of 220, 240, and 260 bar, and injection timings of 21, 23, and 25 °CA before top dead center (bTDC). Results show that karanja biodiesel with enriched hydrogen (KB20H10) increases BTE by 4% than diesel fuel at 240 bar injection pressure and 23° CA bTDC injection timing. For blend KB20H10, the emissions of UHC, CO, and smoke opacity are 33%, 16%, and 28.7% lower than for diesel. On the other hand NOx emissions, rises by 10.3%. The optimal injection parameters for blend KB20H10 were found to be 240 bar injection pressure and 23 °CA bTDC injection timing based on the significant improvement in performance, combustion, and reduction in exhaust emissions.     

Effect of pilot fuel injection pressure and injection timing on combustion,performance and emission of hydrogen-biodiesel dual fuel engine

The present study highlights the influence of fuel injection pressure (FIP) and fuel injection timing (FIT) of Jatropha biodiesel as pilot fuel on the performance, combustion and emission of a hydrogen dual fuel engine. The hydrogen flow rates used in this study are 5lit/min, 7lit/min, and 9lit/min. The pilot fuel is injected at three FIPs (500, 1000, and 1500 bar) and at three FITs (5°, 11°, and 17?bTDC). The results showed an increase in brake thermal efficiency (B_th)from 25.02% for base diesel operation to 32.15% for hydrogen-biodiesel dual fuel operation with 9lit/min flow rate at a FIP of 1500 bar and a FITof17?bTDC. The cylinder pressure and heat release rate (HRR) are also found to be higher for higher FIPs. Advancement in FIT is found to promote superior HRR for hydrogen dual fuel operations. The unburned hydrocarbon (UHC) and soot emissions are found to reduce by 59.52% and 46.15%, respectively, for hydrogen dual fuel operation with 9lit/min flow rate at a FIP of 1500 bar and a FIT of 11?bTDC. However, it is also observed that the oxides of nitrogen (NO_X) emissions are increased by 20.61% with 9lit/min hydrogen flow rate at a FIP of 1500 bar and a FIT of 17?bTDC. Thus, this study has shown the potential of higher FIP and FIT in improving the performance, combustion and emission of a hydrogen dual fuel engine with Jatropha biodiesel as pilot fuel.     

Effect of fuel opening injection pressure and injection timing of hydrogen enriched rice bran biodiesel fuelled in CI engine

Fuel opening injection pressure and injection timing are important injection parameters, and they have a significant influence on engine combustion, performance, and emissions. The focus of this work is to improve the performance and emissions of single-cylinder diesel engines by using injection parameters in engines running with rice bran biodiesel 10% blend (RB10+H₂) and 20% blend (RB20+H₂) with a fixed hydrogen flow rate of 7 lpm. In addition, hydrogen and biodiesel are excellent alternatives to conventional fuels, which can reduce energy consumption and strict emission standards. The investigation is conducted for three different opening injection pressure of 220, 240, 260 bar, and four different injection timings of 20°, 22°, 24°, and 26° bTDC. Results indicate that the sample ‘RB10+H₂’ provides 3.32% higher BTE and reduces the fuel consumption by 13% as diesel fuel. The blend RB10+H₂ attributes a maximum cylinder pressure of 68.7 bar and a peak HRR value of 49 J/ºCA. Further, compared to diesel, RB10+H₂ blend emits lower CO, HC, and smoke opacity by 17%, 22%, and 16%, respectively. However, an almost 12% increase of nitrogen oxides for the RB10+H₂ blend is observed. However, with advanced injection timing and higher opening injection pressure, NOx emissions is slightly increased.     

Optimization of hydrogen-enriched diesel/n-Amyl alcohol-fueled engine to meet emission standards through varying nozzle opening pressure and static injection timing

Important injection parameters such as fuel injection timing (FIT) and fuel injection pressure (FIP) on different piston bowl geometries substantially impact the performance, emissions, and combustion characteristics of a common rail direct injection engine. The aim of this study deals with the effects of piston bowl geometry (hemispherical bowl [HSB], troded bowl [TRB], and re-entrant bowl [REB]), FIP (200, 220, and 240 bar), and variable FIT (20, 24, and 28°bTDC) with hydrogen-diesel/1-pentanol (B20) (80% diesel and 20% pentanol) with a constant flow rate of hydrogen at 12 Lpm. Furthermore, to decrease emission standards and energy consumption, biodiesel and hydrogen are the ideal substitutes for conventional fuels. REB outperforms HSB and TRB in terms of brake thermal efficiency (5.67%) and hydrocarbon (8% reduction), increasing the FIP at full load (240 bar). However, with the increase in the FIP in the REB, a slight reduction in nitrogen oxide (NO_x) emissions (2%) is observed. With an increase in FIP in the case of REB, net heat release rate, peak pressure (in-cylinder), and rate of pressure rise all rise significantly by 3.4%, 4.2%, and 2.3%. NO_x emissions are marginally enhanced with higher FIP and advanced FIT. It is found that changing the piston shape and FIP simultaneously is a potential alternative for improving engine performance and lowering emissions.     

Influence of advanced injection timing on the performance and emissions of CI engine fueled with ethanol‐blended diesel fuel

Ethanol has been considered as an alternative fuel for diesel engines. On the other hand, injection timing is a major parameter that sensitively affects the engine performance and emissions. Therefore, in this study, the influence of advanced injection timing on the engine performance and exhaust emissions of a single cylinder, naturally aspirated, four stroke, direct injection diesel engine has been experimentally investigated when using ethanol‐blended diesel fuel from 0 to 15% with an increment of 5%. The original injection timing of the engine is 27° crank angle (CA) before top dead center (BTDC). The tests were conducted at three different injection timings (27, 30 and 33° CA BTDC) for 30 Nm constant load at 1800 rpm. The experimental results showed that brake‐specific energy consumption (BSEC), brake‐specific fuel consumption (BSFC), NO_x and CO₂ emissions increased as brake‐thermal efficiency (BTE), smoke, CO and HC emissions decreased with increasing amount of ethanol in the fuel mixture. Comparing the results with those of original injection timing, NO_x emissions increased and smoke, HC and CO emissions decreased for all test fuels at the advanced injection timings. For BSEC, BSFC and BTE, advanced injection timings gave negative results for all test conditions. Copyright © 2008 John Wiley & Sons, Ltd.     

Utilization of unattended Putranjiva roxburghii non-edible oil as fuel in diesel engine

The search for alternative sources of energy has been driven by the increased cost and depletion of supply of fossil fuels. The alternatives are mainly vegetable oils. Putranjiva roxburghii, a non-edible vegetable oil can be used in diesel engine for its fuel properties which are comparable with diesel. Blends (10%, 20%, 30%, and 40% v/v) of pure Putranjiva oil and diesel are used in Ricardo Variable Compression Diesel Engine to study the performance and emission characteristics at various brake power. Putranjiva oil blends yield better performance at 45° CA bTDC injection timing in comparison to 40° CA bTDC timing for diesel. Maximum 30% blend of Putranjiva oil with diesel can be used as an alternative fuel in diesel engine for it differs very little from diesel in performance and is better than diesel with regard to emissions.     

Effect of manifold injection of hydrogen gas in producer gas and neem biodiesel fueled CRDI dual fuel engine

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 (NO_x) 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 NO_x, respectively.     

Emission and performance estimation in hydrogen injection strategies on diesel engines

Recently, the increasing demand for energy requires the use of alternative fuels, especially in fossil fueled power systems. As a promising alternative fuel for next-generation diesel engines that utilize fossil fuel, hydrogen fuel is one step ahead due to its positive properties. In this study, the effects of hydrogen on the performance of a diesel engine have been numerically investigated with respect to different injection ratios and timings. The numerical results of the study for 25% load conditions on a single-cylinder, four-stroke diesel engine have been validated against experimental data taken from literature and good agreement has been observed for pressure results. Emission parameters such as NO_x, CO and performance parameters such as cylinder temperature, pressure, power, thermal efficiency and IMEP are presented comparatively.The results of numerical analyses show that the maximum pressure, temperature and heat release rate are observed with injection ratio of H15 and early injection timing (20° CA BTDC). Besides that, engine power, thermal efficiency and IMEP are greatly improved with increasing injection ratio and early injection timing. Although combustion chamber performance parameters improve with rising the hydrogen injection ratio, higher NO_x emissions have also been detected as a negative side effect. Furthermore, while early injection timing increases diesel engine performance, it also causes an increase in NO_x emissions. Therefore, precise determination of injection timing together with the optimum amount of hydrogen has revealed that it brings crucial improvement in engine performance and emissions.     

An experimental investigation on manifold‐injected hydrogen as a dual fuel for diesel engine system with different injection duration

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 (NO_X) 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.     

Experimental investigation on a DI dual fuel engine with hydrogen injection

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. NO_X 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.     

Numerical and experimental investigation of hydrogen enrichment in a dual-fueled CI engine: A detailed combustion,performance, and emission discussion

An effort has been made to simulation a compression ignition engine using hydrogen-diesel, hydrogen-diethyl ether, hydrogen-n-butanol and base diesel fuel as alternatives. The engine measured for the simulation is a single cylinder, four stroke, direct injection, diesel engine. During the simulation the injection timing and engine speed are kept constant at 23°bTDC and 1500 rpm. Diesel-RK, a piece of commercial software employed for this project, can forecast an engine emission, performance and combustion characteristics. The examination of the anticipated outcomes reveals that adding hydrogen to diesel leads in a small increase in efficiency and fuel consumption. With the usage of hydrogen-blend fuels, the majority of dangerous pollutants in exhaust are greatly decreased. The shortest ignition delay was consistently given by 5H295DEE. The lowest CO₂ (578.61 g/kWh) was given by 5H295nB at CR 19.5. Hydrogen blends increase NOx emissions more than base diesel fuel. In the case of smoke and particulate matter emission, the reduce tendency was seen.     

The effect of biodiesel oxidation on engine performance and emissions

Biodiesel is an alternative fuel consisting of the alkyl monoesters of fatty acids from vegetable oils or animal fats. Previous research has shown that biodiesel-fueled engines produce less carbon monoxide, unburned hydrocarbons, and particulate emissions compared to diesel fuel. One drawback of biodiesel is that it is more prone to oxidation than petroleum-based diesel fuel. In its advanced stages, this oxidation can cause the fuel to become acidic and to form insoluble gums and sediments that can plug fuel filters. The objective of this study was to evaluate the impact of oxidized biodiesel on engine performance and emissions. A John Deere 4276T turbocharged DI diesel engine was fueled with oxidized and unoxidized biodiesel and the performance and emissions were compared with No. 2 diesel fuel. The neat biodiesels, 20% blends, and the base fuel (No. 2 diesel) were tested at two different loads (100 and 20%) and three injection timings (3° advanced, standard; 3° retarded). The tests were performed at steady-state conditions at a single engine speed of 1400 rpm. The engine performance of the neat biodiesels and their blends was similar to that of No. 2 diesel fuel with the same thermal efficiency, but higher fuel consumption. Compared with unoxidized biodiesel, oxidized neat biodiesel produced 15 and 16% lower exhaust carbon monoxide and hydrocarbons, respectively. No statistically significant difference was found between the oxides of nitrogen and smoke emissions from oxidized and unoxidized biodiesel.     

Application of response surface methodology to optimize diesel engine parameters fuelled with pongamia biodiesel/diesel blends

ABSTRACT

In the present scenario, the rate of fossil fuel consumption is very high and increasing rapidly which lead to a further increase in air pollution levels. Due to an increase in pollution level, researchers are striving to discover some cleaner and environment-friendly fuels for the diesel engines. This study was focused on the optimization of the input parameters of the diesel engine running on pongamia biodiesel for improvement in the engine performance. The input parameters selected for optimization were fuel injection pressure, fuel injection timing, pongamia biodiesel blends, and engine load with respect to BTE, BSFC, exhaust gas temperature, and P_max. An experimental analysis was performed according to the response surface methodology technique. The best engine input parameters setting for getting optimum performance was found at fuel injection timing 25 bTDC, fuel injection pressure 226 bar, 40% of pongamia biodiesel blending, at 74% of maximum rated engine load. Experimental and optimized results of the output responses at optimum input parameters were compared and found in the suggested error range.     

Comparitive investigation of performance and emission features of methanol,ethanol, DEE,and nanopartilces as fuel additives in diesel-biodiesel blends

The usage of biodiesel blends is restricted due to its low fuel consumption and high thermal NOx. The current study exhibits the usage of four different fuel additives methanol, ethanol, diethyl ether, and NiO nanoparticles in Neem biodiesel blend (NB25) to shore up the usage of neem oil methyl ester. Performance and emission experimentation of a compression-ignition engine fueled with NB25 having fuel additives were conducted at varying injection opening pressures (180, 210, and 240 bar) and static injection timings (19°, 23°, and 27° bTDC). The results indicate that when NiO fuel additives were doped in the NB25 blend, high peaks of NOx were found with betterment in performance features with a lower CO and HC emission.     

Effect of manifold and port injection of hydrogen and exhaust gas recirculation (EGR) in dairy scum biodiesel - low energy content gas-fueled CI engine operated on dual fuel mode

In this current work, exhaustive research work is conducted in three phases, in the initial phase, WFO was used for producing WFO treated biomass and in the second phase, influence of PFIP and PFIT has been examined. Further in the successive phase, effect of hydrogen HMI, HPI and EGR on the combustion and emission characteristics of CRDI diesel engine operated on dual-fuel mode using DiSOME and PG combination is evaluated. In the current study, in a CRDI engine, PFIT was employed ranging from 0 to 15°CA bTDC and changed in steps of 5 and PFIP was used from 600 to 1000 bar and varied in successive steps of 200 bar. Further flow rate of hydrogen was kept 8 L/min constant and HMIT was employed in the range from TDC to 15°aTDC and changed in stages of 5. Correspondingly, HID was varied from 30 to 90°CA with 30°CA dwell and EGR was used in the range from 0 to 15% by vol. and varied in steps of 5. Outcome of the work showed that, DiSOME-PG operation with 10°bTDC PFIT, 800 bar PFIP, 10°aTDC of HMI, 60°CAHID and 5% EGR rate showed lower BTE by 5.8% and increased smoke levels by 10.8%, HC by 8.6%, CO by 6.5% and marginally decreased NOx by 6.4% was observed in comparison to the same fuel blend with zero EGR at 80% load. Further, marginally amplifiedID and CD with loweredCP and HRR has been noticed. Study revealed thatH₂addition to low calorific value gas (PG), method of pilot fuel addition and EGR is affected dual fuel engine performance, but provided drastic reductions in smoke and NOx emissions.     

Investigating the effects of injection and induction modes of hydrogen addition in a CRDI pilot diesel-fuel engine with exhaust gas recirculation

This work compares the outcomes of different flow rates of hydrogen added by induction and injection methods in three different flow rates (3, 9, and 15 LPM) through the intake manifold of a constant speed CRDI diesel engine operated at 1500 rpm. The premixed air and hydrogen mixture was ignited by injecting diesel fuel at 23? bTDC. Hydrogen addition reduced CO, HC, and smoke in both the techniques, but efficiency was decreased at a higher percentage of hydrogen induction, whereas it increased with the injection technique. The higher calorific value and flame velocity helped proper combustion and improved brake thermal efficiency by 7%, and the brake-specific energy consumption was reduced by 10.7%. In addition, CO, UHC, and Smoke were decreased by 15.8, 29.7, and 15% compared with neat diesel at full BMEP. Nitrogen oxides decreased by 5.6% for 15 LPM of hydrogen injection compared to the induction method with the same flow rate but higher than diesel fuel by 35.9%. Three different EGR percentages (5, 7.5, and 10%) were used to reduce the higher NOx emission. Though the injection process was complex compared to the induction method, the injection process can provide promising results even at higher hydrogen flow rates.     

高压直喷点燃式发动机燃用航空煤油掺混乙醇对燃烧性能优化的试验研究

为提高航空煤油在点燃式发动机中的燃烧热效率,改善发动机爆震及拓宽发动机负荷范围,以3号航空煤油(RP3)为基础燃料,以乙醇为辅助燃料,基于一台单缸水冷、压缩比可调、四冲程点燃式发动机结合高压共轨缸内直喷技术,开展了不同负荷、不同乙醇和航空煤油掺混比、不同喷射压力、不同喷射时刻下航空煤油燃烧特性的试验研究。结果表明,在压缩比为7的条件下,由于爆震的限制,发动机负荷仅能达到原机的72.0%。而乙醇具有较强的抑制爆震的能力,随着乙醇在航空煤油中掺混比例的增加,发动机负荷区间不断拓展,当乙醇的掺混比为10%时发动机可实现全负荷工作。继续增大乙醇的掺混比例,可进一步提升功率并降低油耗。为探究喷油时刻对动力性、经济性的影响,试验测定了5种喷油时刻对燃烧性能的影响。当喷油时刻为压缩上止点前300°时,发动机具有较好的动力性;当喷油时刻为上止点前360°时,发动机具有较好的经济性。     

Ignition delay of dual fuel engine operating with methanol ignited by pilot diesel

An investigation on the ignition delay of a dual fuel engine operating with methanol ignited by pilot diesel was conducted on a TY1100 direct-injection diesel engine equipped with an electronic controlled methanol low-pressure injection system. The experimental results show that the polytropic index of compression process of the dual fuel engine decreases linearly while the ignition delay increases with the increase in methanol mass fraction. Compared with the conventional diesel engine, the ignition delay increment of the dual fuel engine is about 1.5° at a methanol mass fraction of 62%, an engine speed of 1600 r/min, and full engine load. With the elevation of the intake charge temperature from 20°C to 40°C and then to 60°C, the ignition delay of the dual fuel engine decreases and is more obvious at high temperature. Moreover, with the increase in engine speed, the ignition delay of the dual fuel engine by time scale (ms) decreases clearly under all engine operating conditions. However, the ignition delay of the dual fuel engine increases remarkably by advancing the delivery timing of pilot diesel, especially at light engine loads.