Effect of induction on exhaust gas recirculation and hydrogen gas in compression ignition engine with simarouba oil in dual fuel mode

Biofuels extracted from non-edible oil is sustainable and can be used as an alternative fuel for internal combustion engines. This study presents the performance, emission and combustion characteristic analysis by using simarouba oil (obtained from Simarouba seed) as an alternative fuel along with hydrogen and exhaust gas recirculation (EGR) in a compression ignition (CI) engine operating on dual fuel mode. Simarouba biofuel blend (B20) was prepared on volumetric basis by mixing simarouba oil and diesel in the proportion of 20% and 80% (v/v), respectively. Hydrogen gas was introduced at the flow rate of 2.67 kg/min, and EGR concentration was maintained at 30% of total air introduction. Performance, combustion and emission characteristics analysis were examined with biodiesel (B20), biodiesel with hydrogen substitution and biodiesel, hydrogen with EGR and were compared with neat diesel operation. Results indicate that BTE of the engine operating with biodiesel B20 was decreased when compared to neat diesel operation. However, introducing hydrogen along with B20 blend into the combustion chamber shows a slight increase in the BTE by 1%. NO_x emission was increased to 18.13% with the introduction of hydrogen than that of base fuel (diesel) operation. With the introduction of EGR, there is a significant reduction in NO_x emission due to decrease in in-cylinder temperature by 19.07%. A significant reduction in CO, CO_2, and smoke emissions were also noted with the introduction of both hydrogen and EGR. The ignition delay and combustion duration were increased with the introduction of hydrogen, EGR with biodiesel than neat diesel operation. Hence, the proposed biodiesel B20 with H₂ and EGR combination can be applied as an alternative fuel in CI engines.     

Effect of hydrogen enrichment in the intake air of diesel engine fuelled with honge biodiesel blend and diesel

In the current investigation, the enrichment of hydrogen with the honge biodiesel blend and diesel is used in a compression ignition engine. The biodiesel is derived from the honge oil and mixed with diesel fuel by 20% (v/v). Thereafter, hydrogen at different volume flow rates (10 and 13 lpm) is introduced into the intake manifold. The outcomes by enrichment of hydrogen on the performance, combustion and emission characteristics are investigated by examining the brake thermal efficiency, fuel consumption, HC, CO, CO₂, NOₓ emissions, in-cylinder pressure, combustion duration, and rate of heat release. The engine fuelled with honge biodiesel blend is found to enhance the thermal efficiency, combustion characteristics. Compare to diesel, the BTE increased by 2.2% and 6% less fuel consumption for the HB20 + 13H₂ blend. Further, reduction in the emission of exhausts gases like CO and HC by 21% and 24%, respectively, are obtained. This is due to carbon-free structure in hydrogen. Moreover, due to high pressure in the cylinder, there is a slight increase in oxides of nitrogen emission compare to diesel. The combustion characteristics such as rate of heat release, combustion duration, and maximum ₂rate of pressure rise and in-cylinder pressure are high due to hydrogen.     

Utilization of pyrolytic oil and hydrogen enriched syngas from single feedstock (delonix regia) through pyrolysis process and its influence on performance and emission characteristics in CI engine

The main objective of the present investigation is to conduct the performance, combustion and emission analysis of CI engine operated using hydrogen enriched syngas (pyrolytic gas) and biodiesel (pyrolytic oil) as dual fuel mode condition. Both the pyrolytic oil and syngas is obtained from single feedstock delonix regia fruit pod through pyrolysis process and then pyrolytic oil is converted into biodiesel through esterification. Initially biomass is subjected to thermal degradation at various pyrolysis temperature ranges like 350–600 °C. During the pyrolysis process syngas, pyrolytic oil and char are produced. The syngas is directly used in the CI engine and pyrolytic oil is converted into biodiesel and then used in the CI engine. The pyrolytic oil and syngas is subjected to FTIR and GC/TCD analysis respectively. The syngas analysis confirms the presence of various gases like H₂, CH₄, CO₂, CO and C₂H₄ in different proportions. The various proportions of the syngas is mainly depending upon the reactor temperature and moisture content in the biomass. The syngas composition varies with increase in the temperature and at 400 °C, higher amount of hydrogen is present and its composition are H₂ 28.2%, CO is 21.9%, CH₄ is 39.1% and other gases in smaller amounts. The biodiesel of B20 and syngas of 8lpm produced from the same feedstock are considered as test sample fuels in the CI engine under dual fuel mode operation to study the performance and emission characteristics. The study reveals that BTE has slight increase than diesel of 1.5% at maximum load. On the another hand emission like CO, HC and smoke are reduced by 15%,25% and 32% respectively at full load condition, whereas NO_x emission is increased at all loads in the range of 10–15%. Therefore B20+syngas of 8lpm can be used as an alternative fuel in CI engine without any modification and major products from pyrolysis process with waste biomass is fully used as fuel in the CI engine.     

Effect of hydrogen and ethanol addition in cashew nut shell liquid biodiesel operated direct injection (DI) diesel engine

In this experimental research, the hydrogen gas at a different flow rate (4 lpm, 8 lpm, & 12 lpm) is introduced into the intake port of a diesel engine fueled with B20 (20% CNSL (Cashew nut shell liquid) + 80% diesel) biodiesel blend to find out the best H₂ flow rate. Then, ethanol-blended (5%, 10%, and 15% by volume) B20 blend along with the best H₂ flow rate are tested in the same engine to examine the engine performance. The experimental results showed that B20 with 8 lpm H₂ flow gives the maximum brake thermal efficiency and subsequently reduces the BSFC. Furthermore, by blending ethanol with the B20 blend, the BTE of the engine is improved further. The 10% ethanol blended B20 blend with 8 lpm hydrogen flow gives the maximum BTE of 37.9% higher than diesel whose values are 33.6% at full load. Also, this fuel combination led to the maximum reduced levels of CO and HC emissions with an increase in exhaust gas temperature and NOx emissions. From the results, the 10% ethanol blended B20 blend with 8 lpm H₂ flow dual-fuel configuration is recommended as an alternative to sole diesel fuel.     

Effect of natural antioxidant additive on hydrogen-enriched biodiesel operated compression ignition engine

The environmental degradation and depletion of fossil fuel, urges the need of renewable fuel for IC engines. Among the renewable fuel, biodiesel are widely used as alternative fuel but for recent years hydrogen is also considered as alternative fuel because of zero emission but it possess higher auto ignition temperature. In order to reduce the self-ignition temperature of hydrogen and another liquid fuel is mixed and operated as a dual fuel mode condition in CI engine. The current investigation aims to analyse the impact of natural antioxidant additive on hydrogen-enriched biodiesel operation in a diesel engine. During the experimentation process hydrogen is admitted at the intake manifold and B20 blend of juliflora biodiesel is injected in combustion cylinder. The three test fuel samples are used for the experimentation process such as diesel, B20 and B20 with hydrogen in different flow rates such as 8, 10, 12, 16,20lpm. B20 with hydrogen shows an increment of brake thermal efficiency (BTE). Among the test fuels B20 + 16lpm and B20 + 20lpm blends have better improvement of BTE of 28.815% and 28.32%, which is higher than the conventional engine at maximum load CO, HC emission is also lower for B20 + 16lpm and B20 + 20lpm than other blends but the NO_x emission increases of 26 and 28% than diesel respectively. In order to minimize the NO_x emission, natural antioxidant additive Melia Azedarach (MA) of 1000 ppm is added to B20 + 16lpm and found that B20 + 16lpm with MA shows an improvement of BTE 2.17% higher than B20 + 16lpm without additive and the NO_x emission for B20 + 16lpm with additive is 1079 ppm, which is 21.9% lower than B20 + 16lpm without additives. Therefore B20 + 16lpm with additive is superior than other test blends.     

Effect of hydrogen enrichment and TiO2 nanoparticles on waste cooking palm biodiesel run CRDI engine

In this study, we deal with the production and utilization of waste-cooking palm biodiesel (WCB) and.evaluated the influence of the addition of titanium dioxide (TiO₂) nanoparticles in hydrogen-enriched single-cylinder CRDI diesel engine. XRD, SEM, and EDX decide the structure and morphology of TiO₂ nanoparticles. The TiO₂ nanoparticles were dispersed in the tested fuels at a dosage of 50–75 ppm with the aid of ultra-sonication. Based on the oxidation stability study, the B20 + 75 ppm (TiO₂) fuel blend is the pilot fuel for the engine test. Further, the engine is enriched with a hydrogen (H₂) flow of 10 lpm. Results revealed that the performance parameters were improved with the addition of H₂ enrichment and TiO₂ nanoparticles compared to D. The brake thermal efficiency of the engine was improved by 8.21%. In comparison, brake-specific fuel consumption decreased by 42.86%. Furthermore, adding nanoparticles also reduced CO and HC emissions by 74% and 27.27%, respectively, whereas the NO_x emission was slightly increased. Thus, the findings demonstrated that hydrogen-enriched nanoparticles added to biodiesel might be considered a substitute for fossil fuels and report a positive impact on diesel engine performance without requiring significant modifications.     

Effects of oxyhydrogen on the CI engine fueled with the biodiesel blends: A performance,combustion and emission characteristics study

The main purpose of this study is to analyse the effects of oxy hydrogen (HHO) along with the Moringa oleifera biodiesel blend on engine performance, combustion and emission characteristics. HHO gases were generated using the typical electrolysis process using the potassium hydroxide solution. The experiments were performed under various engine loads of 25%, 50%, 75%, and 100% in a constant speed engine. Biodiesel from the M. oleifera was prepared by the transesterification process. Further, the procured biodiesel blends mixed with neat diesel at the concentration of 20% (B20) and 40% (B40). In addition to above, the HHO gas flow rate to the engine chamber maintained at the flow rate of 0.5 L^-1. The use of the 20% and 40% blends with HHO reported less BTE compared to the neat diesel. However, B20 reported marginal rise in the BTE due to the addition of the HHO gas. On the other hand, addition of HHO gas to the blends significantly dropped the brake specific fuel consumption. With regard to the emissions, addition of the biodiesel blends reduced the concentration of the CO, HC, and CO₂. Nevertheless, no reduction reported in the formation of the NO. However, adding the HHO to the biodiesel reduced the average NOx by 6%, which is a substantial effect. Overall, HHO enriching biodiesel blends are the potential replacement for the existing fossil fuels for its superior fuel properties compared to the conventional diesel.     

Comparative performance analysis of diesel engine fuelled with hydrogen enriched edible and non-edible biodiesel

In the present study, a comparative analysis of enrichment of hydrogen alongside diesel fuel and two different sources of biodiesel namely rice bran oil is an edible oil, and karanja oil being non-edible is tested. Hydrogen at a fixed flow rate of 7 lpm is inducted through the intake manifold. A total of six fuel samples are considered: diesel (D), hydrogen-enriched diesel (D + H₂), hydrogen-enriched 10, and 20% rice bran biodiesel blend (RB10 + H₂ and RB20 + H₂), and hydrogen-enriched 10 and 20% karanja biodiesel blend (KB10 + H₂ and KB20 + H₂). Results indicate that enrichment of hydrogen improves combustion and results in 2.5% and 1.6% increase in the brake thermal efficiency of diesel fuel and rice bran biodiesel, respectively. For karanja biodiesel the increment is negligible. Fuel consumption of the D + H? is 6.35% lower and for RB10 + H? and KB10 + H? it is decreased by 2.9% and 1.3%, respectively. The Presence of hydrogen shows the 4–38% lower CO emissions and 6–14% lower UHC emission due to better combustion. The blends RB10 + H? and KB10 + H? produce up to 6–13% higher NOx emission and that for the blends RB20 + H? and KB20 + H? it goes up to 25%. Overall rice bran oil is found to provide better performance than karanja biodiesel.     

Influence of surfactants on quaternary emulsion blend and experimental investigations on the influence of hydrogen enriched quaternary blend in DICI engine

In this research work, phase behaviour of the synthesized Schizochytrium algae biodiesel, diesel and octanol was studied with water in oil emulsions (Quaternary blend). The effects of different hydrophilic lipophilic balance were investigated by varying the ratio of Span 80 and Tween 80 (20–100%) in the quaternary blend to find an optimum HLB number. The optimum fuel blend of HLB number 12 (Span 20%: Tween 80%) showed no phase separation for 25 days. The influence of hydrogen addition in quaternary blend (QB20) and biodiesel blend (B20) under variable hydrogen flow rates (1 l/min and 2 l/min) was investigated to improve the engine parameters using dual fuel mode of operation. The dual fuel mode of operation increased the brake thermal efficiency from 29.71% for quaternary blend to 32.01% with the addition of 2 l/min hydrogen. In terms of emission, UHC was reduced by 30% and 5% for QB20 + 1 l/m H2 and QB20 + 2 l/m H2, respectively. The maximum of 11% CO emission was reduced by the hydrogen inducted QB20 + 2 l/m H2 blend.     

The characteristics of waste-cooking palm biodiesel-fueled CRDI diesel engines: Effect hydrogen enrichment and nanoparticle addition

The influence of iron nanoparticle (INP) addition (75 ppm) and hydrogen enrichment (10 lpm) with waste cooking palm biodiesel blend (WCB) on a CRDI diesel engine is evaluated. A blend of 20% WCB and 80% diesel is used, and the dosing level of INP has been kept at 75 ppm, which has been decided based on the oxygen content of biodiesel. Results indicate that the combination of H₂ enrichment and INP addition improves the BTE and BSFC of biodiesel blends as that of diesel. A maximum improvement of BTE of 7.1% than that of diesel is obtained at 90% loading. The combined impact of better hydrogen combustion characteristics and improved air-fuel mixing with nanoparticles reduces CO and HC emissions by 37.5% and 41.8%, respectively, for the WCB fuel sample. However, NO_X emission shows an elevation of 27.4% compared to diesel. Combustion parameters, namely ICP (80.1 bar) and HRR (89.5 J/˚CA) indicate an improvement of 5.3% and 6.7% compared to diesel for WCB + INP + H₂. This is owing to the combination of hydrogen's rapid flame speed and INP-added biodiesel's increased thermal conductivity.     

Performance and emission study on the effect of oxygenated additive in neat biodiesel fueled diesel engine

This work presents the effect of the Di-tetra-butyl-peroxide (DTBP) as an oxygenated additive on neat used mustard oil biodiesel (B100) to evaluate the emission and performance engine characteristics. Four fuels, namely, diesel, biodiesel (Mustard biodiesel), a blend of B100-10percentage, and 20% by volume of DTBP (BD90DTBP10 and BD80DTBP20) are prepared and tested on a single cylinder, constant speed diesel engine. Experimental outcomes revealed that 20% of DTBP reduces 7.3% CO, 5.1% HC, and 4.6% NOx and 3.2% smoke emissions of B100. From this study, further, it is inferred that BD80DTBP20 blend could be utilized as an alternative fuel for a CI engine with no modifications in engine design.     

Partial hydrogenation and hydrogen induction: A comparative study with B20 operation in a turbocharged CRDI diesel engine

Numerous studies explored the possibility and effective strategies for supplementing hydrogen along with fossil or biofuels on internal combustion engines. Hydrogen is also being employed for formulating fuels such as hydrogen compressed natural gas in the gaseous form and hydrogenated biofuels in the liquid form. The present study evaluates (i) hydrogen usage on the fuel formulation and (ii) investigates the engine operation of an automotive turbocharged diesel engine operated with karanja biodiesel blended diesel (B20) as a reference fuel. Existing literature outlines that biodiesel blends possess lower energy content and emit higher nitric oxide (NO) emission than fossil diesel. The present research paper partially hydrogenates karanja biodiesel using an autoclave reactor with a palladium catalyst to increase the saturation levels and mitigate the biodiesel-NO penalty. Besides, the drop in energy release of B20 is compensated through the provision of hydrogen induction along the intake manifold. The hydrogen flow rates to the turbocharged engine are maintained at a fixed energy share of 10%. Both biodiesel and hydrogenated biodiesel were blended on a volume basis (20%) with fossil diesel (80%) and are designated as B20 and HB20, respectively. The test results reveal that HB20 effectively mitigates the biodiesel-NO penalty with a maximum reduction of 29.8% compared to B20. Further, hydrogen induction yielded a significant improvement (23.7%) in fuel consumption with HB20 relative to B20 without hydrogen addition. The compounding effect of hydrogen usage on the engine operation and fuel formulation exhibited a better performance and emission trade-off at mid load conditions.     

Effect of ethanol blending with biodiesel on engine performance and exhaust emissions in a CI engine

The use of biodiesel as an alternative diesel engine fuel is increasing rapidly. However, due to technical deficiencies, they are rarely used purely or with high percentages in unmodified diesel engines. Therefore, in this study, we used ethanol as an additive to research the possible use of higher percentages of biodiesel in an unmodified diesel engine. Commercial diesel fuel, 20% biodiesel and 80% diesel fuel, called here as B20, and 80% biodiesel and 20% ethanol, called here as BE20, were used in a single cylinder, four strokes direct injection diesel engine. The effect of test fuels on engine torque, power, brake specific fuel consumption, brake thermal efficiency, exhaust gas temperature, and CO, CO₂, NO_x and SO₂ emissions was investigated. The experimental results showed that the performance of CI engine was improved with the use of the BE20 especially in comparison to B20. Besides, the exhaust emissions for BE20 were fairly reduced.     

Environment effect of La2O3 nano-additives on microalgae-biodiesel fueled CRDI engine with conventional diesel

In this present work, corn oil biodiesel with La₂O₃ was used as an additive with neat diesel fuel and blends were prepared. La₂O₃ nanoparticles are dispersed in the emulsions with different dosage levels of 50, 75, and 100 ppm. A single-cylinder, four-stroke CRDI diesel engine is made to run on different fuel concentrations to study the effect of emission characteristics of the fuel. The test engine was operated under constant engine speed (1500 rpm) and different engine load test conditions. According to the experimental results, fuel blends with biodiesel fuel emission increases CO₂ and NOx and reduces the CO, HC, and smoke emissions compared with the B20 fuel.     

Performance,emission and combustion characteristic of a multicylinder DI diesel engine running on diesel–ethanol–biodiesel blends of high ethanol content

Feasibility of using high percentage of ethanol in diesel–ethanol blends, with biodiesel as a co-solvent and properties enhancer has been investigated. The blends tested are D70/E20/B10 (blend A), D50/E30/B20 (blend B) D50/E40/B10 (blend C), and Diesel (D100). The blends are prepared to get maximum percentage of oxygen content but keeping important properties such as density, viscosity and Cetane index within acceptable limits. Experiments are conducted on a multicylinder, DI diesel engine, whose original injection timing was 13° CA BTDC. The engine did not run on blends B and C at this injection timing and it was required to advance timing to 18° and 21° CA BTDC to enable the use of blends B and C respectively. However advancing injection timing almost doubled the NO emissions and increased peak firing pressure. The P–θ and net heat release diagrams shows that the combustion process of these blends delayed at low loads but approaches to the diesel fuel at high loads. The comparison of blend results with baseline diesel showed that brake specific fuel consumption increased considerably, thermal efficiency improved slightly, smoke opacity reduced remarkably at high loads. NO variation depends on operating conditions while CO emissions drastically increased at low loads. Blend B which replaced 50% diesel and having oxygen content up to 12.21% by weight has given satisfactory performance for steady state running mode up to 1600 RPM however, it does not showed any benefit on peak smoke emission during free acceleration test.     

Inhibition of NO emission by adding antioxidant mixture in <Emphasis Type="Italic">Jatropha</Emphasis> biodiesel on the performance and emission characteristics of a C.I. engine

In this paper, the effect of adding an antioxidant mixture in Jatropha biodiesel as fuel, in a single cylinder, direct injection compression ignition engine was experimentally investigated and the level of pollutants in the exhaust and performance characteristics of the engine were analyzed. Nine test fuels were prepared with three antioxidants, namely, Succinimide (C₄H₅NO₂), N,N-dimethyl-p-phenylenediamine-dihydrochloride (C₈H₁₄Cl₂N₂), and N-phenyl-p-phenylenediamine (C₆H₅NHC₆H₄NH₂) added to neat biodiesel at 500 parts per million (ppm), 1000 ppm and 2000 ppm and the observed experimental results were compared with those of neat biodiesel and neat diesel as base fuels. The comparison showed that NO emission was reduced drastically for the test fuels with the antioxidant addition of 2000 ppm. The maximum reduction of 10% of NO emission was observed for the antioxidant mixture in neat biodiesel, with a slight increase in unburned HC, CO and smoke opacity. In addition, the obtained experimental results reveal that the addition of two antioxidants as mixture in neat biodiesel caused improved NO emission reduction for all test fuels.     

Hydrogen dual-fuelling of compression ignition engines with emulsified biodiesel as pilot fuel

Dual-fuel compression ignition (CI) engine operation with hydrogen is a promising method of using hydrogen gas in CI engines via high-cetane pilot fuel ignition. However, hydrogen dual-fuel operation with neat pilot fuels typically produce: high NO_x emissions; and high combustion chamber pressure rise rates (leading to increased “Diesel knock” tendencies). While water-in-fuel emulsions have been used during normal CI engine operation to cool the charge and slow combustion rates in an effort to reduce NO_x emissions, these water-in-fuel emulsions have not been tested as pilot fuels during hydrogen dual-fuel combustion. In this work two water-in-biodiesel emulsions are tested as pilot fuels during hydrogen dual-fuel operation. Hydrogen dual-fuel operation generally produces at best comparable thermal efficiencies compared with normal CI engine operation, while the emulsified biodiesel pilot fuels generally increase thermal efficiencies when compared with the neat biodiesel pilot fuel during dual-fuel operation. There is also a clear reduction in NO_x emissions with emulsified pilot fuel use compared with the neat pilot fuel. The thermal efficiency increase is more apparent at higher engine speeds, while the NO_x reduction is more apparent at lower speeds. This is due to two conflicting effects (exclusive to emulsified pilot fuel) that occur in tandem. The first is the cooling effect of water vapourisation on the charge, while the second is the microexplosion phenomenon which enhances fuel-air mixing. The NO_x emission reduction is due to the emulsified pilot fuel lowering pressure rise rates compared with the neat pilot fuel, while the efficiency increase is due to a more homogeneous charge resulting from the violent microexplosion of the emulsified pilot fuel. Smoke, CO, HC and CO₂ emissions remain comparable to neat pilot fuel tests. Overall, emulsified pilot fuels can reduce NO_x emissions and increase thermal efficiencies, however not at the same instance and under different operating conditions. The general trends of reduced power output, reduced CO₂ and increased water vapour emission during hydrogen dual-fuel operation (with neat pilot fuels) are also maintained.     

Hydrogen addition to tea seed oil biodiesel: Performance and emission characteristics

Compression ignition engines are the dominant tools of the modern human life especially in the field of transportation. But, the increasing problematic issues such as decreasing reserves and environmental effects of diesel fuels which is the energy source of compression ignition engines forcing researchers to investigate alternative fuels for substitution or decreasing the dependency on fossil fuels. The mostly known alternative fuel is biodiesel fuel and many researchers are investigating the possible raw materials for biodiesel production. Also, hydrogen fuel is an alternative fuel which can be used in compression ignition engines for decreasing fuel consumption and hazardous exhaust emissions by enriching the fuel. In this study, influences of hydrogen enrichment to diesel and diesel tea seed oil biodiesel blends (B10 and B20) were investigated on an unmodified compression ignition engine experimentally. In consequence of the experiments, lower torque and higher brake specific fuel consumption data were measured when the engine was fuelled diesel biodiesel blends (B10 and B20) instead of diesel fuel. Also, diesel biodiesel blends increased CO₂ and NO_x emissions while decreasing the CO emissions. Hydrogen enrichment (5 l/m and 10 l/m) was improved the both torque and brake specific fuel consumption for all test fuels. Furthermore, hydrogen enrichment reduced CO and CO₂ emissions due to absence of carbon atoms in the chemical structure for all test fuels. Increasing flow rate of hydrogen fuel from 5 l/m to 10 l/m further improved performance measures and emitted harmful gases except NO_x. The most significant drawback of the hydrogen enrichment was the increased NO_x emissions.     

A study on the effect of hydrogen enriched intake air on the characteristics of a diesel engine fueled with ethanol blended diesel

This work aims to replace conventional diesel fuel with low and no carbon fuels like ethanol and hydrogen to reduce the harmful emission that causes environmental degradation. Pursuant to this objective, this study investigated the performance, combustion, and emission characteristics of the diesel engine operated on dual fuel mode by ethanol-diesel blends with H₂ enriched intake air at different engine loads with a constant engine speed of 1500 rpm. The results were compared to sole diesel operation with and without H₂ enrichment. The ethanol/diesel was blended in v/v ratios of 5, 10, and 15% and tested in a diesel engine along with a 9 lpm H₂ flow rate at the intake manifold. The results revealed that 10% ethanol with 9 lpm H₂ combination gives the maximum brake thermal efficiency, which is 1% and 4.8% higher than diesel with and without H₂ enrichment, respectively. The brake specific fuel consumption of the diesel-ethanol blends with H₂ flow increased with increasing ethanol ratio in the blend. When the ethanol ratio increased from 5 to 10%, in-cylinder pressure and heat release rate were increased, whereas HC, CO, and NO_x emissions were decreased. At maximum load, the CO and HC emission of 10% ethanol blend with 9 lpm H₂ case decreased by about 50% and 28.7% compared to sole diesel. However, NO_x emission of the same blend was 11.4% higher than diesel. From the results, the study concludes that 10% ethanol blended diesel with a 9 lpm H₂ flow rate at the intake port is the best dual-fuel mode combination that gives the best engine characteristics with maximum diesel replacement.     

Combustion and emission characteristics of an off-road diesel engine fuelled with biodiesel–diesel blends

In this work, the combustion and emission characteristics were studied in a 186FA diesel engine fuelled with biodiesel–diesel to examine the effect of the percentage of biodiesel in the blends, and the experimental investigation was conducted with various blending ratios of biodiesel under different operating conditions. In addition, the combustion noise of the diesel engine fuelled with biodiesel–diesel was analysed, and then the emission characteristics of NO_x and soot were studied through simulation analysis where the formation rate and distribution of NO_x and soot for pure diesel and B20 fuel were described. Based on the simulation data of the original diesel engine fuelled with B20 fuel, the swirl ratio and fuel injection timing were optimised and the technical measures were suggested to reduce the two different emissions simultaneously. The simulation results showed the emission characteristics were optimal when the swirl ratio was 2.7 and fuel injection timing was 7.5° degree of crank angle before top dead centre respectively.