Direct Injection Diesel Engine Research Articles

Oxidation-induced variations in the physical and fragmentation characteristics of exhaust soot from DMC-diesel blend: Effect of NO presence in the air atmosphere

This study investigated the changes in physical properties (including morphology, primary particle diameter, fractal dimension, and nanostructure) and fragmentation characteristics of exhaust soot from a modern direct injection diesel engine fueled with diesel (D100) and its blend with 7 vol% of dimethyl carbonate (DMC7) during oxidation processes in air and air-NO atmospheres. Soot particles (D100 soot and DMC7 soot) with specific oxidation degrees (0%, 20%, 50%, and 80%) were produced using a thermogravimetric analyzer, then applied to a high-resolution transmission electron microscopy to generate images. The results exhibited that the morphology for D100 soot and DMC7 soot transformed similarly through oxidation, experiencing an increase in fractal dimension, and a decrease in primary particle diameter, while the introduction of NO to the air accelerated these transformations. Additionally, the nanostructure of both soot particles was gradually ordered through oxidation, as evidenced by longer fringe length, narrower separation distance, and lower tortuosity, while DMC7 soot showed lower order degree compared to D100 soot. Interestingly, the ordering processes of soot nanostructure were decelerated as NO was involved in the oxidation process. Furthermore, the aggregate fragmentation rate for both soot particles declined over the oxidation process, while the possibility for primary particle fragmentation increased overall. Moreover, DMC7 soot exhibited significantly lower aggregate fragmentation rate and higher possibility for primary particle fragmentation than D100 soot at the same oxidation stage. This suggests that DMC7 soot is more susceptible to internal oxidation compared to D100 soot. Furthermore, the presence of NO in the air promoted aggregate fragmentation, while reducing the possibility of primary particle fragmentation.

Effects of Blended Diesel-Biodiesel Fuel on Emissions of a Common Rail Direct Injection Diesel Engine with Different Exhaust Gas Recirculation Rates.

The aim of the study was to investigate the exhaust gas emissions and fuel consumption of a common rail direct injection (CRDI) diesel engine using mixed diesel (B10) and biodiesel (B20-B100) fuels. The study's primary objective was to determine the effects of blended diesel-biodiesel fuel on CRDI emissions based on different exhaust gas recirculation (EGR) rates, including carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2), nitrogen oxide (NOx), and hydrocarbon (HC) emissions, smoke opacity, exhaust gas temperature, and fuel consumption. The CRDI experiments involved adjusting the different engine speeds (1400-3000 rpm) and EGR rates (0 and 12.5%), which were analyzed to determine their impact on these parameters for both blended diesel and biodiesel fuels. The results showed that under the conditions of no EGR (0%), the CO and HC emissions and the smoke opacity were lower than those with a 12.5% EGR rate for all fuel types and all cases. With 12.5% EGR rate, the O2 emissions and the EGT of the CRDI diesel engine decreased, which resulted in significantly lower NOx emissions because of EGR into the combustion chamber. For the maximum engine speed of 3000 rpm and with no EGR, the CO and HC emissions and the smoke opacity were lower than those with a 12.5% EGR rate for all fuel types. With a 12.5% EGR rate at 3000 rpm, the O2 emissions and the exhaust gas temperature were reduced by 0.07% and 2.27%, respectively, and the NOx emissions were reduced by 2.54%. However, with EGR, the CO and HC emissions and the smoke opacity increased by 7.70%, 18.61%, and 0.4%, respectively. Furthermore, the fuel consumption of pure biodiesel (B100) at 3000 rpm with a 12.5% EGR rate was reduced by 2.81% compared to that with a 0% EGR rate. Because the temperature in the combustion chamber is high enough for the engine to run, the EGR reuses a portion of the exhaust gases and can help to minimize the quantity of fuel in the combustion chamber. As a suggestion based on these observations, biodiesel fuel should not exceed B80 because the viscosity and density of fuel that are too high may affect the fuel injection system, both the injectors, and the pressure pump, causing the injectors to be unable to work correctly. These findings can contribute to the development of strategies and technologies for reducing emissions and improving fuel efficiency in CRDI diesel engines.

Energy, exergy, emissions and sustainability assessment of hydrogen supplemented diesel dual fuel turbocharged common rail direct injection diesel engine

The present investigation involves the study of Mahindra & Mahindra Supro BS VI Twin Cylinder Turbocharged CRDI Diesel Engine modified to operate under dual fuel mode utilizing hydrogen as a secondary fuel and neat diesel as a pilot fuel. The tests were carried out at constant speed of 2200 rpm (±20 rpm) under three different loading conditions i.e. BMEP values of 1.38 bar, 3.47 bar and 5.6 bar using H2 enrichment of 0%, 10%, 20%, 30% and 40% respectively along with neat diesel. The performance characteristics of the engine are evaluated using energy-exergy and emissions-based approach along with sustainability studies. The results show that turbocharging significantly improves volumetric and indicated thermal efficiency of engine. At BMEP of 5.6 bar, D + H2 (40%) exhibited highest energy efficiency of 28.94% and exergy efficiency of 28.41% compared to baseline diesel fuel. The irreversibilities due to combustion, mixing, friction and unaccounted reasons was found to be the minimum for D + H2 (40%) at higher BMEP values. Emission analysis revealed that trade-off takes place between nitrogen oxides and smoke opacity (%) with hydrogen substitution to baseline diesel fuel. The sustainability analysis revealed that, D + H2 (40%) has the highest exergy performance coefficient and sustainability index compared to all other cases. From the results, it can be concluded that D + H2 (40%) is the most suitable fuel combination for the Twin Cylinder Turbocharged CRDI Diesel Engine.

Comparative assessment of the effects of higher alcohols/diesel blends on performance and emissions of a direct-injection diesel engine

Comparative assessment of the effects of higher alcohols/diesel blends on performance and emissions of a direct-injection diesel engine

Screening nano additives for favorable NOx/smoke emissions trade-off in a CRDI diesel engine fueled by industry leather waste fat biodiesel blend

The depletion of petroleum reserves and increasing environmental concerns prompted significant research into alternative fuels. This work, biodiesel, is extracted from the byproduct of industrial leather waste fat to generate beneficial energy.The main objective of this study is to enhance common rail direct injection (CRDI) diesel engine outcome characteristics by substituting industrial leather waste fat biodiesel (ILWFB) with the mixing of aluminium nitrate (Al (NO3)3) nanoparticles and graphene oxide nanoplates (GONPS) in the proportion of 50 ppm (parts per million) as catalysts to enhance ignition process. This research found that with the mixing of Al (NO3)3 nanoparticles and GONPS 50 ppm into the ILWFB blend, the in-cylinder pressure increased by 0.463% and 1.5%, and the heat release rate (HRR) improved by 4.19% and 12.04% than diesel and ILWFB blend at maximum load circumstances. Brake thermal efficiency (BTE) increased by 3.1% and 5.27%, and brake specific fuel consumption (BSFC) decreased by 3.57% and 7.14% in D50ILWFB50+Al (NO3)3 50 ppm blend and D50ILWFB50+GONPS 50 ppm blend related to diesel fuel. The carbon monoxide (CO), hydrocarbon (HC), and smoke emissions were reduced by 26.84%, 13.11%, and 5.75% in D50ILWFB50+Al (NO3)3 50 ppm blend and 38.94%, 21.31%, and 9.12% decreased in D50ILWFB50+GONPS 50 ppm blend than diesel fuel. Oxides of nitrogen (NOx) emissions marginally increased by 3.66%, 5.42%, and 8.94% in ILWFB blend, D50ILWFB50+Al (NO3)3, and D50ILWFB50+GONPSrelated to pure diesel at peak load conditions. This work concluded that the nano additives effectively enhanced BTE and decreased BSFC, CO, HC, and smoke emissions in diesel engine applications.

Experimental investigations of CI engine performance using ternary blends of n-butanol/biodiesel/diesel and n-octanol/biodiesel/diesel

This study explored the ternary blends of biodiesel-diesel-n-butanol and biodiesel-diesel-n-octanol on common rail direct injec-tion (CRDI) diesel engines. The compositions of fuels, which varied from 0% to 100%, were altered by up to 5%. On the basis of their properties, these blends were chosen, with various concentrations of alcohol at 5% and 10%, 5% diesel, and the remainder being biodiesel. Two ternary fuel blends of waste cooking oil biodiesel (90–85%), diesel (5%), and butanol (5–10%), namely BD90D5B5 and BD85D5B10, and subsequently, another two ternary similar blends of waste cooking oil biodiesel (90–85%), diesel (5%), and octanol (5–10%), namely BD90D5O5 and BD85D5O10, were used to conduct the experiments. The experiments were done with varying injection pressure from 17° to 29° crank angle (CA) before top dead centre (bTDC). The optimum con-dition for the blends is achieved at 26°CA bTDC for 80% loading. So, the engine trials were conducted on 26°CA bTDC to attain the results. The BD90D5O10 blend achieved the lowest brake specific fuel consumption (BSFC) reading of 0.308 kg/kWh while operating at full load. The maximum brake thermal efficiency (BTE) was 31.46% for BD90D5B5. The maximum heat release rate (HRR) achieved with BD85D5O5 fuel blend was 58.54 J/°CA. The quantity of carbon monoxide that BD85D5B10 created was the lowest (25.86 g/kWh). BD85D5B10 had a minimal unburned hydrocarbon emission of 0.157 g/kWh while operating at full load. Oxides of nitrogen (NOx) were emitted in the maximum quantity by BD85D5O10, which was equal to 6.01 g/kWh. This study establishes the viability of blends of biodiesel and alcohol as an alternative for petro-diesel in the future to meet the growing global energy demand.

Adaptation and Validation of Injection Rate Predictive Model for Solenoid Type Injectors with Different Nozzle Geometry

The present research analyses the injection rate of a direct rail injection diesel engine, focusing specifically on the influence of the nozzles and various operating conditions from real road tests on the rate of injection. A diesel injector test bench was used for feedback with real data from the test vehicle under real road conditions. An analysis of the behaviour of the injection rate was carried out using the zero-dimensional model. This model generated a predictive model that incorporated the five variables identified through a developed multivariate analysis of variance, showing a high correlation of dependence between variations in injection pressure, the diameter of the holes, and the number of holes with greater representativeness. The results obtained showed that the nozzle geometry and the physical properties of the fuel had a direct effect on the injection rate. This analysis enriches the understanding of fuel injection and its effects on diesel engine performance by providing an analysis of the system components that influence the injection rate and generating a simple tool to feed thermodynamic diagnostic models. The proposal model may be used as an input in thermodynamics predictive models and reduce the simulation load in computational fluid dynamics predictive models.

Numerical and experimental investigation of performance and emission characteristics of hydrogen enrichment with prosopis juliflora biodiesel in CI engine using RSM and ANN optimization

IC engines need renewable fuel due to environmental degradation and fossil fuel depletion. Biodiesel was a popular alternative fuel. However, hydrogen has zero emissions and a higher auto ignition temperature. This study examines diesel engine operation with hydrogen-enriched juliflora biodiesel/diesel blend (B20). The 4-Stroke, direct injection diesel engine (KIRLOSKAR-AV1) produces 5.2 kW at 1500rpm. A B20 compound was injected into the combustion cylinder via the intake manifold during testing. Hydrogen was supplied through the intake manifold. Diesel (D0), B20, and B20 with hydrogen are tested on 6 lpm, 9 lpm, and 12 lpm respectively. Increase in hydrogen concentration with B20 blend will increased brake thermal efficiency. The mixture B20 at a flow rate of 12 L per minute increased the BTE by 27.51%, which is a 4.88% improvement compared to the original B20. Similarly, this concentration exhibit an 18.75% reduced Brake Specific Fuel Consumption (BSFC) compared to the B20 combination. CO and HC emissions decreases and increased in NOx emissions while increasing H2 flow. Further, to develop the RSM and ANN predicted model for optimization of CI engine characteristics responses. The RSM model analyzed the lower mean square error (MSE) and actual relative error (ARE) for the engine responses compared to the ANN model.

Optimization and impact of modified operating parameters of a diesel engine emissions characteristic utilizing waste fat biodiesel/di-tert-butyl peroxide blend

This study comprehensively investigated the transesterification process of converting waste pork fat oil into biodiesel as a fuel for the common rail direct injection (CRDI) diesel engine. In addition, Di-tert-butyl peroxide (DTBP) is used as an ignition enhancer to minimize exhaust gas emissions. The test fuels are diesel and diesel-waste pork fat biodiesel (WPFB)-DTBP blend (B20DTBP10 by volume), were used to analyze the engine outcome parameters with modified engines operating conditions like various compression ratios (CRs 16, 17.5, and 19) and injection pressures (IPs 400, 500 and 600 bar) at maximum load. The experiment results revealed that higher CRs and IPs, the heat release rate (HRR) and cylinder pressure increased. The brake thermal efficiency (BTE) is enhanced by increasing CRs and IPs but lowered than neat diesel. Smoke opacity decreased while increasing CRs and IPs. At CR 19 and IP 600 bar, smoke opacity decreased by 18.29%, related to baseline diesel. Increasing CRs and IPs lowered HC and CO emissions, but increasing IPs increased both emissions. HC and CO emissions were lowered in CR 19 and IP 500 bar by 21.73% and 28.49% more than neat diesel. The lower CRs and IPs, the oxides of nitrogen (NOx) emissions decreased, but further increasing CRs and IPs, the NOx emissions increased. Compared to baseline diesel, NOx emissions decreased in CR 16 and IP 400 bar by 15.49%. It was discovered that with increasing CRs and IPs, the emissions decreased with a minor rise in NOx emissions. Furthermore, the experimental results matched the predictions of an artificial neural network (ANN) model. The research concluded that the blend B20DTBP10 with modified engine operating conditions CRs and IPs suits diesel engine operation.

0/1 and 3 - dimensional cold flow analysis of a diesel engine: A case study

Gas motion in the engine cylinder plays a critical role in diesel engines' air-fuel mixing and combustion processes. Moreover, it influences the engine's performance, emissions, and heat transfer. The intake air motion regulates the main phases of the flow in the cylinder, which is characterized by swirl, squish, and turbulence. Inducing swirl and tumble in the intake process provides high turbulence levels at ignition, resulting in more effective flame speeds and better combustion for lean air-fuel ratios or with EGR. Computational fluid dynamics (CFD) software is used to enhance in-cylinder flow characteristics. In this study, a cold flow simulation of a naturally aspirated, direct injection diesel engine was conducted with different piston bowls using AVL Fire M R2022.2. Swirl, tumble, and TKE parameters were investigated to make a detailed analysis of the in-cylinder flow for the relevant engine. Contrary to the expectation, the swirl ratio for the Piston B configuration is less than that for the original piston configuration. It causes a decrement of swirl ratio compared to the initial piston geometry and the maximum decrement is about 19%. In both cases, the second peak of TKE corresponding to the reverse-squish is around at the -30 CA and the difference between the curves is about ±8%.

Integrated optimization of common rail direct injection diesel engine input parameters with linseed biodiesel: A hybrid approach using grey relational analysis and genetic algorithm techniques

In the pursuit of improved productivity and efficiency, the search for alternative fuels that reduce dependence on fossil fuels is of utmost importance. This research study aims to investigate the influence of process parameters, namely blend percentage, fuel injection pressure, exhaust gas recirculation (EGR) rate, and engine load, on various engine performance parameters such as torque, brake thermal efficiency (BTE), brake mean effective pressure (BMEP), hydrocarbon emissions (HC), and mechanical efficiency. The experiments are conducted following the Taguchi orthogonal array (L25) design of experiments. Additionally, grey relational analysis, a multi-objective optimization technique, is applied to identify the optimal levels of the process variables that optimize all the response parameters. The optimal values obtained through grey relational analysis are determined as 0% blend, 600 bar fuel injection pressure, 12% EGR rate, and 12 kg engine load. Moreover, the Genetic Algorithm-based Multi-Objective Genetic Algorithm (MOGA) is employed for multi-objective optimization of the engine input variables, yielding optimal levels of 19.45% blend, 594.35 bar fuel injection pressure, 14.12% EGR rate, and 12 kg engine load. Furthermore, multivariable regression models are developed to predict the response variables within the experimental domain. These models are validated through a confirmation test. The findings of this study provide insights into the optimization of process variables for enhanced engine performance, with the developed models serving as valuable tools for future predictions and optimization.

Vibration analysis using wavelet transformation technique and performance characteristics of a diesel engine fueled with tamarind biodiesel-diesel blends and diverse additives

This study investigates the combustion, performance characteristics, and emission levels of diesel and tamarind biodiesel mixtures (B20, B30, B40, and B100) in a single-cylinder, four-stroke, direct injection (DI) diesel engine. Further, two fuel additives, namely Butylated Hydroxytoluene (BHT) (an antioxidant) and Diethyl ether (DEE) (a cetane improver), were separately added to B20 to enhance the engine characteristics. In addition, Wavelet Transform and Wavelet Packet algorithms were used to investigate the vibration behaviour of the tested fuels. The results demonstrate that the B20 blend improved the performance and generated less emission than the other blends. Moreover, the brake thermal efficiency (BTE) and brake-specific fuel consumption (BSFC) for B20+BHT were 3.8% higher and 4.1% less than B20, respectively. B20+DEE combustion showed lower CO and smoke pollutants by 51% and 19% compared to B20, respectively. The NOx emissions for the blends containing BHT and DEE were decreased by 16% and 9%, respectively. The engine vibration analysis showed almost the same frequency with fuel blends B20 and B30, which were similar to the diesel fuel values. The results concluded the tamarind biodiesel/diesel mixtures with BHT and DEE improved the performance and emissions behaviors of DI diesel engine and could be considered a potential alternative biofuel for such engines. Wavelet analysis of the engine was accurately employed to extract the prominent features of the vibrations.

Studies on CRDI diesel engine performance and emissions using waste plastic oil and fly ash catalyst

Fossil fuels are quickly draining on a daily basis, causing fuel product prices to increase throughout the world. There is a crucial need to develop new alternate fuels from various sources that meet our daily requirements, like industries, mining, building construction, transportation, electric power generation from rural areas, etc. In the present study, mono-use low density polyethylene (LDPE) was successfully transformed into a liquid form of hydrocarbon fuel with fly ash-supported catalytic pyrolysis. The ratio of 0.1 with reference to catalyst-to-feedstock was fixed for the preparation of waste plastic oil (WPO) using batch-type pyrolysis reactors. About 180 °C was the temperature at which the extracted crude oil was segregated. The diesel fuel’s properties and those of the WPO fuel were compared and evaluated. Experiments were carried out using diesel-WPO mixed fuel (10%, 20%, 30%, and 40%) in a multi-cylinder, water-cooled Common Rail Direct Injection (CRDI) diesel engine. Additionally, the impact of the compression and mixing ratios on performance, emission characteristics, and combustion was studied. We observed significant improvement in the results of BTE and BSFC for the tested fuel blend, D80WPO20, compared to other blends. Additionally, it has been demonstrated that the emissions of CO, HC, and NOx rise with an increasing fuel mixing ratio. Based on the analysis carried out on performance and emissions, it was determined that D80WPO20 was the best combination.

A novel approach to enhance the combustion quality of C5 alcohol with 2-Ethylhexyl nitrate as a cetane enhancer in common rail direct ignition diesel engine

The purpose of this investigation is to explore the effect of 1-Pentanol and 2-Ethylhexyl nitrate (2-EHN), on the characteristics of a common rail direct injection (CRDI) diesel engine. The major feedstock for the production of 1-pentanol (bio-alcohol) is non food biomass waste. The conversion of waste biomass into useful energy contributes to the cleaner production of fuel and its utilization. The trial was conducted in a 2-cylinder CRDI test rig. The engine was fuelled with diesel, 40P60D (40% 1-Pentanol & 60% diesel v/v) and then 500, 1000 and 2000 ppm of 2-EHN was doped to 40P60D. The addition of 1-Pentnaol showed a slight negative effect on combustion at low and medium loads. Furthermore, an extension in the delay period (DP) and combustion duration (CD) was seen for 1-Pentanol blend. The doping of 2-EHN, enhances the cetane count and leads to improvement in the combustion parameters and a reduction in DP and CD was noted. The 1000 ppm of 2-EHN doped blend showed 8.7% of higher BTE and 8.61% lower BSEC compared to 40P60D, also 1.89% and 50% lower HC and CO at 80% load and 36.9% lower NO at 60% load in contrast to diesel. Among all the concentrations 1000 ppm of 2-EHN showed satisfactory results. It is concluded that 40% of 1-Pentanol with 1000 ppm of 2-EHN can be used as an alternative fuel to pure diesel without compromising in performance of the engine.

Effect of Alumina and Bio‐Based Calcium Oxide Nanoadditives on Reduction of Emissions and Performance Improvement in a Common Rail Direct Injection Diesel Engine Fueled with B20 Blend of Waste Cooking Oil Biodiesel

This experimental study investigates the performance, combustion, and emission characteristics of a common rail direct injection diesel engine running on used cooking biodiesel prepared through transesterification. The nanoparticles calcium oxide (CaO) and alumina (Al2O3) are mixed with the B20 blend using an ultrasonicator to create a homogeneous mixture. The following five fuel series are used in the study: a B20 blend with three different nanoparticle ppms are blended to form Al2O3CaO 90 ppm, Al2O3 + CaO 60 ppm, and Al2O3 + CaO 30 ppm. The enhanced surface area to volume ratio of nanoparticles enhances the degree of mixing and chemical reactivity during combustion. Also, the characteristics of diesel engines result in reduced specific fuel consumption. The test fuel B20 + 90 ppm (90 ppm nanoparticles dispersion) results 9% and 11% increase in brake thermal efficiency compared to diesel and B20, respectively. The presence of nanoparticles in biodiesel has initiated the combustion slightly earlier due to its improved ignition qualities that permit catalytic combustion and a shorter ignition delay. In comparison to diesel and B20, the Al2O3CaO90 ppm fuel blend lowers NOx emissions by 18% and 21%, carbon monoxide emissions by 40% and 43%, hydrocarbon emissions by 35% and 40%, and smoke emissions by 24% and 29%, respectively.

Experimental investigation on biodiesel–diesel blends in a single-cylinder DI diesel engine

The present study analyses the utilisation of biodiesel–diesel blends in a single-cylinder diesel engine. Biodiesel is prepared via conventional transesterification with standard conditions (60°C reaction temperature, 1% by wt. catalyst, 7.5:1 molar ratio and 120 min reaction time). The test engine utilised is a single-cylinder naturally aspirated direct injection diesel engine. The test engine is operated at 100% load with different engine speeds ranging from 1000 to 2400 rpm. Performance, combustion and emission characteristics were analysed at different engine speeds. The MB10 blend (10% biodiesel + 90% diesel) has resulted in higher brake power of 7.43%, lowered brake-specific fuel consumption and carbon dioxide by 7.49% and 7.6%, respectively. Also, it can be concluded that the MB10 blend lowered the smoke by 24% and hydrocarbon by 10.34% with respect to neat diesel. The MB20 blend resulted in a lowered CO profile than the CO profile of diesel fuel by about 0.84%. However, the MB10 blend’s average CO profile is improved by 1.97% than mineral diesel. These results are compromised with higher CO and NOx profiles of 2.4% and 8.9%, respectively.

Performance of a single cylinder diesel engine fuelled with emulsified residual oleins and standard diesel fuel

Emulsified residual oleins and standard diesel fuel were evaluated. The engine tests for the fuels analyzed were performed in a Petter single cylinder direct injection diesel engine under steady state conditions at fixed torque values (20 Nm and 34 Nm) and the engine speeds (n) between 1300-1700 rpm. Power output, specific fuel consumption, ignition delay and exhaust composition were evaluated. The emulsified residual oleins (ERO) shown lower power output joint to a higher specific fuel consumption related to the lower heating value of residual oleins compared to diesel fuel. A shorter ignition delay was observed for the ERO. Decreases in NOx emission were obtained for ERO compared to diesel fuel. The use of ERO in order to be a partial or full alternative to the use of diesel fuel for energy production was achieved.

Engine performance of a single cylinder direct injection diesel engine fuelled with blends of Jatropha Curcas oil and standard diesel fuel

Blends of Jatropha Curcas oil and standard diesel fuel were evaluated (without pre-heating). The engine tests for the blends were performed in a Petter single cylinder direct injection diesel engine under steady state conditions at high loads. Engine speeds between 1300-1700 rpm were selected for the engine tests. Torque, power output, specific fuel consumption, in cylinder pressure, ignition delay, rate of heat released and exhaust composition were evaluated. The tested blends between 10-20% of oil shown lower effective torque and power output joint to a higher specific fuel consumption related to the lower heating value of Jatropha oil compared to diesel fuel. Lower pressure peaks and rates or pressure rises were observed when Jatropha blends are used. A decrease in the rate of heat released and shorter ignition delay were observed for the blends. Decreases in HCand CO emissions were observed for blends compared to diesel fuel. Both alternatives assessed shown that the differences observed compared to diesel fuel, can be partially restored with engines regulation. The use of Jatropha oil in order to be a partial or full alternative to the use of diesel fuel for energy production was achieved.

ENHANCING PERFORMANCE OF BIODIESEL-HYDROGEN BLENDS OPERATED DI DIESEL ENGINE USING VARIABLE INJECTION TIMING

The study aimed to investigate the effect of injection timing (IT) on the combustion, emission, and performance characteristics of a single-cylinder, four-stroke, direct injection (DI) diesel engine. The engine was run on different fuel blends, namely, pure diesel, diesel blended with 20% mahua oil methyl ester (B20) with three hydrogen flow rates of 20, 22.5, and 25 liters per minute (lpm). The experiment was carried out at a rated speed of 2000 rpm. Four different injection timings (ITs) were applied, namely, 19°, 23°, 27°, and 31° bottom top dead center (BTDC), relative to the standard IT of 23° BTDC. The results showed that the optimal IT was 27° BTDC for B20-hydrogen (22.5 lpm) dual-fuel mode operation. This condition delivered the highest brake thermal efficiency (BTE) between 24.4 and 34.3% , the lowest brake-specific fuel consumption (BSFC) between 0.25 and 0.41 kg/KWh, and the minimum unburnt hydrocarbon (HC) emissions between 8 and 32 ppm, and carbon-monoxide (CO) emissions ranging between 0.002 and 0.389% . However, the concentration of nitrogen-oxides (NOx) emissions was slightly increased, ranging between 24 and 53 ppm compared to B20. Further modifications in the IT resulted in decreased brake thermal efficiency ranging between 13 and 31% , increased hydrocarbon emissions between 25 and 28% , and increased CO emissions between 70 and 96% for both 4° BTDC advancements and retardations. Moreover, both modifications reduced NOx emissions by 8-19% . Hence, based on this study's findings, employing an IT of 27° BTDC for 22.5 Ipm of hydrogen with a B20 dual-fuel mode of operation for the DI diesel engine to achieve optimal performance, combustion, and emission characteristics is recommended.

Performance evaluation of direct injection diesel engine fueled with diesel-ZnO nanoparticles blends

Present experimental study focused on investigating the effects of diesel-zinc oxide nanoparticles blends on the performance evaluation of a four stroke two-cylinder direct injection diesel engine. Two blends were employed to analyze engine combustion and performance parameters at various engine loads and constant speed (1500 rpm) conditions. Blends were prepared by dispersing zinc oxide nanoparticles with diesel fuel in different dosing levels through the ultrasonication process. One blend has 30 ppm zinc oxide nanoparticles per liter of diesel (D100ZnO30) and another has 60 ppm zinc oxide nanoparticles per liter of diesel (D100ZnO60). It was found that combustion and performance characteristics improved at higher engine loads for all blends. Present experimental results revealed that blending of zinc oxide nanoparticles in diesel fuel enhance engine performance due to better in-cylinder combustion. Combustion characteristics like maximum cumulative heat release, maximum net heat release rate and peak rate of pressure rise of diesel engine were promoted due to nanoparticles additive. Percentage increase of 9.09 and 10.09 in duration of combustion of D100ZnO30 and D100ZnO60 blends respectively than diesel was recorded at full load. At full load conditions, brake thermal efficiency was improved by 2.63 % and 0.36 % for D100ZnO30 and D100ZnO60 blends respectively as compared to diesel. Moreover, brake specific fuel consumption of D100ZnO30 and D100ZnO60 blends also improved significantly than diesel. Hence, it can be stated that zinc oxide nanoparticles in lower concentration would be an effective approach to significantly improve diesel engine combustion and performance parameters.