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 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.     

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 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 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.     

Optimization of diesel engine input parameters running on Polanga biodiesel to improve performance and exhaust emission using MOORA technique with standard deviation

Fast exhausting fossil fuel reserves and high rise in the air pollution levels due to combustion of these fuels bound us to discover some cleaner and environment-friendly fuels for the engines. Biodiesel from edible and non-edible seed oils has been identified as a better alternate of the diesel fuel in engines with a little sacrifice in terms of power output but with an improvement in exhaust emissions. The aim of the present research work is to optimize the input parameters of diesel engine running on Polanga biodiesel to improve performance and exhaust emissions. The input parameters selected for optimization are fuel injection timing, fuel injection pressure, Polanga biodiesel blend, and engine load with respect to brake thermal efficiency, brake specific fuel consumption, hydrocarbon emission, smoke opacity, and emission of nitrogen oxides. Relative weights of the response variables were calculated by standard deviation. The optimum combination of input parameters was obtained by Taguchi-based Multi-Objective Optimization by Ratio Analysis. Experiments were performed according to Taguchi’s L₁₆ orthogonal array in a random manner in which three replicates of each experiment were noted. The optimum combination of input parameters for maximum performance and minimum exhaust emissions found to be as fuel injection timing 27° bTDC, fuel injection pressure –? 220 bar, biodiesel blend –? B40, and engine load –? 60%. The optimum values of the response variables, at the obtained optimum combination of input parameters, were predicted by Taguchi method and then verified experimentally and a good relation was found between them. These optimum values found to be as brake thermal efficiency –? 36.351%, brake specific fuel consumption –? 0.322 kg/kW-h, hydrocarbon emission –? 2.193 ppm, smoke opacity –? 80.925 HSU, and NO_x emission –? 690.987 ppmv.     

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.     

Influence of 1-pentanol as the renewable fuel blended with hydrogen on the diesel engine characteristics and trade-off study with variable injection timing

Biofuels are considered as one of the best viable and inexhaustible alternatives to conventional diesel fuel. Alcohols have become very important and popular in the present scenario due to their characteristic fuel properties and production nature. This study examines the influence of 1-pentanol and hydrogen on various performance characteristics of CRDI diesel engines. The experiment was carried out with a load range of 25%–100% in 25% percent increments, at 1500 rpm constant engine speed. The influence of injection-timing at 9°, 12°and 15°bTDC was first investigated using 30% 1-pentanol as fuel to observe the effect on engine parameters in comparison with base fluid. Compared to conventional and retarded injection timings, 1-pentanol displayed better emission and performance characteristics at higher injection timings. Additionally, at 15°bTDC, 30% 1-pentanol was used with 12 LPM hydrogen in a dual fuel mode. Compared to plain diesel, the hydrogen-enriched fuel resulted in a 1.50% lower HRR (heat release rate) and 6.77% higher cylinder pressure at 75% load. Thus, it is evident that hydrogen enrichment at 75% load effectively reduces hydrocarbon and nitrogen oxide emissions by 6.66% and 10%, respectively, and improves thermal efficiency by 5%. The experiment revealed that 1-pentanol performs effectively at higher injection timings and that hydrogen improved the performance even further. Furthermore, the long-term viability of hydrogen and 1-pentanol as an energy source is well demonstrated in future scenarios.     

Prediction of performance,combustion and emission characteristics of diesel-thermal cracked cashew nut shell liquid blends using artificial neural network

This paper explores the use of artificial neural networks (ANN) to predict performance, combustion and emissions of a single cylinder, four stroke stationary, diesel engine operated by thermal cracked cashew nut shell liquid (TC-CNSL) as the biodiesel blended with diesel. The tests were performed at three different injection timings (21°, 23°, 25°CA bTDC) by changing the thickness of the advance shim. The ANN was used to predict eight different engine-output responses, namely brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), exhaust gas temperature (EGT), carbon monoxide (CO), oxide of nitrogen (NO _x ), hydrocarbon (HC), maximum pressure (P _max) and heat release rate (HRR). Four pertinent engine operating parameters, i.e., injection timing (IT), injection pressure (IP), blend percentage and pecentage load were used as the input parameters for this modeling work. The ANN results show that there is a good correlation between the ANN predicted values and the experimental values for various engine performances, combustion parameters and exhaust emission characteristics. The mean square error value (MSE) is 0.005621 and the regression value of R ² is 0.99316 for training, 0.98812 for validation, 0.9841 for testing while the overall value is 0.99173. Thus the developed ANN model is fairly powerful for predicting the performance, combustion and exhaust emissions of internal combustion engines.     

Study of the oxidation stability and exhaust emission analysis of Moringa olifera biodiesel in a multi-cylinder diesel engine with aromatic amine antioxidants

In this study, the two most effective aromatic amine antioxidants N,N′-diphenyl-1,4-phenylenediamine (DPPD) and N-phenyl-1,4-phenylenediamine (NPPD), were used at a concentration of 2000 ppm. The impact of antioxidants on the oxidation stability, exhaust emission and engine performance of a multi-cylinder diesel engine fuelled with MB20 (20% Moringa oil methyl ester and 80% diesel fuel blend) were analysed at varying speed conditions at an interval of 500 rpm and a constant load. It was observed that, blending with diesel enhanced the oxidation stability of the moringa biodiesel by approximately 6.97 h, and the addition of DPPD and NPPD to MB20 increased the oxidation stability up to 34.5 and 18.4 h, respectively. The results also showed that the DPPD- and NPPD-treated blends reduced the NOx emission by 7.4% and 3.04%, respectively, compared to the untreated blend. However, they do have higher carbon monoxide (CO) and hydrocarbon (HC) levels and smoke opacities, but it should be noted that these emissions are still well below the diesel fuel emission level. The results show that the addition of antioxidant with MB20 also improves the engine's performance characteristics. Based on this study, MB20 blends with amine antioxidants can be used in diesel engines without any modification.     

A nonlinear regression based multi-objective optimization of parameters based on experimental data from an IC engine fueled with biodiesel blends

This study reports the results of an experimental investigation of the performance of an IC engine fueled with a Karanja biodiesel blends, followed by multi-objective optimization with respect to engine emissions and fuel economy, in order to determine the optimum biodiesel blend and injection timings complying with Bharat Stage II emission norms. Nonlinear regression has been used to regress the experimentally obtained data to predict the brake thermal efficiency, NO_x, HC and smoke emissions based on injection timing, blend ratio and power output. To acquire the data, experimental studies have been conducted on a single cylinder, constant speed (1500 rpm), direct injection diesel engine under variable load conditions and injection timings for neat diesel and various Karanja biodiesel blends (5%, 10%, 15%, 20%, 50% and 100%). Retarding the injection timing for neat Karanja biodiesel resulted in an improved efficiency and lower HC emissions. A tradeoff relationship between the NO_x and smoke emissions is observed, which makes it difficult to determine the optimum blend ratio. The functional relationship developed between the correlating variables using nonlinear regression is able to predict the performance and emission characteristics with a correlation coefficient (R) in the range of 0.95-0.99 and very low root mean square errors. The outputs obtained using these functions are used to evaluate the multi-objective function of optimization process in the 0-20% blend range. The overall optimum is found to be 13% biodiesel-diesel blend with an injection timing of 24°bTDC, when equal weightage is given to emissions and efficiency.     

Effect of diethyl ether additive in Jatropha biodiesel-diesel fuel blends on the variable compression ratio diesel engine performance and emissions characteristics at different loads and compression ratios

An investigational analysis was performed to assess the effect of diethyl ether (DEE) that acts as an oxygenated additive in Jatropha biodiesel and diesel fuel blends on the performance enhancement and emission reduction of a variable compression ratio (CR) diesel engine. The DEE (10% vol) is added to different concentration levels of Jatropha biodiesel (B5, B10, and B20). The Jatropha biodiesel (JME) is prepared by the transesterification reaction and DEE is prepared through acid distillation of ethanol. The various tests were conducted by varying the loads at 25%, 50%, 75%, and 100% (3, 6, 9, and 12 kg). The DEE was entirely miscible with diesel and Jatropha biodiesel, the addition of DEE increases the cetane and calorific value, kinematic viscosity of the fuel blends compared with neat diesel or Jatropha biodiesel. The results illustrate that at higher loads and CRs, the engine performance parameters such as brake thermal efficiency enhances and reduces the brake-specific fuel consumption for DEE-Jatropha biodiesel-diesel fuel blends. Blend A3 (10% DEE + 20% JME + 70% diesel) demonstrated an overall improvement in the engine performance parameters and emission characteristics compared with A1, A2, and diesel fuel blends. It is concluded that the DEE-JME-diesel fuel blend is a promising source of fuel for diesel engine at maximum load.     

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.     

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

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

Biodiesel fuel in diesel micro-turbine engines: Modelling and experimental evaluation

Many performance and emission tests have been carried out in reciprocating diesel engines that use biodiesel fuel over the past years and very few in gas turbine engines. This work aims at assessing the thermal performance and emissions at full and partial loads of a 30 kW diesel micro-turbine engine fed with diesel, biodiesel and their blends as fuel. A cycle simulation was performed using the Gate Cycle GE Enter software to evaluate the thermal performance of the 30 kW micro-turbine engine. Performance and emission tests were carried out on a 30 kW diesel micro-turbine engine installed in the NEST laboratories of the Federal University of Itajubá, and the performance results were compared with those of the simulation. There was a good agreement between the simulations and the experimental results from the full load down to about 50% of the load for diesel, biodiesel and their blends. The biodiesel and its blends used as fuel in micro-turbines led to no significant changes in the engine performance and behaviour compared to diesel fuel. The exhaust emissions were evaluated for pure biodiesel and its blends and conventional diesel. The results revealed that the use of biodiesel resulted in a slightly higher CO, lower NO_x and no SO₂ emissions.     

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.     

Biodiesel production from waste chicken fat based sources and evaluation with Mg based additive in a diesel engine

In this study, chicken fat biodiesel with synthetic Mg additive was studied in a single-cylinder, direct injection (DI) diesel engine and its effects on engine performance and exhaust emissions were studied. A two-step catalytic process was chosen for the synthesis of the biodiesel. Methanol, sulphuric acid and sodium hydroxide catalyst were used in the reaction. To determine their effects on viscosity and flash point of the biodiesel, reaction temperature, methanol ratio, type and amount of catalyst were varied as independent parameters. Organic based synthetic magnesium additive was doped into the biodiesel blend by 12 μmol Mg. Engine tests were run with diesel fuel (EN 590) and a blend of 10% chicken fat biodiesel and diesel fuel (B10) at full load operating conditions and different engine speeds from 1800 to 3000 rpm. The results showed that, the engine torque was not changed significantly with the addition of 10% chicken fat biodiesel, while the specific fuel consumption increased by 5.2% due to the lower heating value of biodiesel. In-cylinder peak pressure slightly rose and the start of combustion was earlier. CO and smoke emissions decreased by 13% and 9% respectively, but NO_x emission increased by 5%.     

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.     

Comparative evaluations of injection and spray characteristics of a diesel engine using karanja biodiesel–diesel blends

The injection and spray characteristics of a diesel engine with 7.4‐kW rated power output for use of different karanja biodiesel blends (B10 and B20) are studied for identifications of further scope of performance improvement and emission reduction. The dynamic injection timing advanced for the biodiesel blends resulting in higher NOx emission, which increased from 2.94 g/kW‐hour with base diesel to 3.40 g/kW‐hour with B20. At the rated load, the dynamic injection timing advanced from 9.2 deg. crank angle before top dead centre (CA BTDC) with base diesel to 9.3 and 9.4 deg. CA BTDC for B10 and B20, respectively. The in‐line injection pressure increased from 460 bar with base diesel to 480 bar with B20, and in‐cylinder injection duration also increased from 9.5 deg. CA with base diesel to 10.2 deg. CA with B20. The penetration distance increased from 33.37 mm with base diesel to 34.80 mm and 34.25 mm with B10 and B20, respectively. Sauter mean diameter (SMD) increased from 11.39 µm with base diesel to 12.71 and 17.09 µm for B10 and B20, respectively, at the rated load. Air entrainment increases for the biodiesel blends, and it enhances the mixing rate of injected fuel with surrounding hot air. Vaporization time of biodiesel droplets increases because of larger SMD. However, increase in over penetration distance, large SMD and high vaporization time for the biodiesel blends would lead to deteriorated performance and emission characteristics of diesel engines. The remedial measures of spray characteristics for further performance improvement and emission reduction also are highlighted in the paper. Copyright © 2011 John Wiley & Sons, Ltd.