Experimental and RSM-based Analysis of Hydrogen-enriched Microalgae Biodiesel Combustion in a CI Engine

Biodiesel is considered to be a promising alternative option to diesel fuel. The main contribution of the current work is to improve compression ignition engine performance, fueled by several biodiesel blends. Three metrics were used to evaluate the output performance of the compression ignition engine, as follows: brake torque (BT), brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE), by varying two input parameters (engine speed and fuel type). The engine speeds were in the 1200–2400 rpm range. Three biodiesel blends, containing 20 vol.% of vegetable oil and 80 vol.% of pure diesel fuel, were prepared and tested. In all the experiments, pure diesel fuel was employed as a reference for all biodiesel blends. The experimental results revealed the following findings: although all types of biodiesel blends have low calorific value and slightly high viscosity, as compared to pure diesel fuel, there was an improvement in both BT and brake power (BP) outputs. An increase in BSFC by 7.4%, 4.9%, and 2.5% was obtained for palm, sunflower, and corn biodiesel blends, respectively, as compared to that of pure diesel. The BTE of the palm oil biodiesel blend was the lowest among other biodiesel blends. The suggested work strategy includes two stages (modeling and parameter optimization). In the first stage, a robust fuzzy model is created, depending on the experimental results, to simulate the output performance of the compression ignition engine. The particle swarm optimization (PSO) algorithm is used in the second stage to determine the optimal operating parameters. To confirm the distinction of the proposed strategy, the obtained outcomes were compared to those attained by response surface methodology (RSM). The coefficient of determination (R2) and the root-mean-square-error (RMSE) were used as comparison metrics. The average R2 was increased by 27.7% and 29.3% for training and testing, respectively, based on the fuzzy model. Using the proposed strategy in this work (integration between fuzzy logic and PSO) may increase the overall performance of the compression ignition engine by 2.065% and 8.256%, as concluded from the experimental tests and RSM.

Alternative fuels can be produced from both non-edible feedstocks and edible crops. The higher production costs and contaminating nature of vegetable biofuels, which cause engine component failure, make it conceivable to encourage the synthesis of biodiesel from non-edible sources. One of the most widely utilized alternative fuels is Jatropha biofuel, which has performance levels comparable to diesel fuels and can be used with CI (Compression Ignition) engines without any modifications. However when it comes to oxidative stability properties that impact shelf life and commercialization, the majority of biodiesels—including Jatropha—are lacking. Therefore, the objective of this study was to enhance the oxidative stability and other physicochemical parameters, such performance and emission characteristics, of Jatropha biodiesel with diesel blends by adding additives like DEE (diethyl ether) and MA (moringa oleifera antioxidant). The seeds of jatropha and moringa were harvested by hand and then mechanically extracted with a screw press. A conical flask containing the precisely weighed amount of oil is filled with 50 mL of neutral alcohol. The combination is then heated for an hour using a water condenser over a bath. Using phenolphthalein indicator, the contents are titrated with KOH solution after cooling. Weight of oil taken (w)/volume of KOH used (mL) × normality of KOH is the formula used to determine the acidity value of jatropha oil. It is therefore below the minimum level set by ASTM D 675, which is 2.5 mg KOH/g. Methanol was used in the transesterification process to produce biodiesel, and potassium hydroxide (KOH) was used as a catalyst. Then, using 5 % DEE and 10 % MA additives, the physicochemical properties of jatropha biodiesel—such as density, kinematics viscosity, calorific value, and oxidative stability—were characterized. The percentage of improvement of the biodiesel's mentioned properties with these additives was 0.68 %, 2.8 %, 0.73 %, and 33.8 %, respectively. The brake thermal efficiency (BTE) of B40MA10DEE05D45 increased by 8.52 % whereas the brake specific fuel consumption (BSFC) of B50MA10DEE05D35, which is Made up of 44 % diesel, 50 % jatropha biodiesel, 5 % DEE, and 10 % MA fuels, declined by 5.14 %. As a result of these additions, the blended fuel's CO, HC, and NOx emissions were reduced by 3.51 %, 2.25 %, and 8.64 %, respectively. Therefore, a 20 % blend of Jatropha biodiesel and diesel containing antioxidants from Moringa can be used in compression ignition engines without the need for engine modifications and with high oxidation stability.

This study investigates the potential of green-synthesized nanoparticles (NPs) doped with a 20% biodiesel blend to enhance the performance and emissions characteristics of a compression ignition (CI) engine. The green synthesis of NPs offers an environmentally friendly alternative to conventional methods, while the addition of biodiesel provides a renewable fuel source. Experimental trials were conducted using various concentrations of NP-doped biodiesel blends in a CI engine. Performance parameters such as brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), and exhaust gas temperature (EGT) were measured. Additionally, emissions profiles, including smoke intensity, carbon monoxide (CO), oxides of nitrogen (NOx), and unburned hydrocarbons (HC), were analyzed. The results demonstrated that the incorporation of NP-doped biodiesel blends led to significant improvements in engine performance. A reduction in BSFC and an increase in BTE were observed, indicating enhanced fuel efficiency. Furthermore, the NP-doped blends contributed to a substantial decrease in smoke, NOx and other harmful emissions, suggesting a positive environmental impact. This research highlights the promising potential of green-synthesized NPs and biodiesel blends as a sustainable and efficient fuel alternative for CI engines.

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

LHV predication models and LHV effect on the performance of CI engine running with biodiesel blends

To reduce the amount of carbon dioxide released from transportation the EU has implemented legislation to mandate the renewable content of petrol and diesel fuels. However, due to the complexity of the combustion process the addition of renewable content, such as biodiesel and ethanol, can have a detrimental effect on other engine emissions. In particular the engine load can have a significant impact on the emissions. Most research that have studied this issue are based on steady state tests that are unrealistic of real world driving and will not capture the difference between full and part loads. This study aims to address this by investigating the effect of renewable fuel blends of diesel, biodiesel and ethanol on the emissions of a compression ignition engine tested over the World Harmonised Light Vehicle Test Procedure (WLTP). Diesel, biodiesel and ethanol were blended to form binary and ternary blends, the ratios were determined by Design of Experiments (DoE). The total amount of emissions for CO, CO2 and NOx as well as the fuel consumption, were measured from a 2.4 L compression ignition (CI) engine running over the WLTP drive cycle. The results depicted that percentages smaller than 10% of ethanol in the fuel blend can reduce CO emissions, CO2 emissions as well as NOx emissions, but increases fuel consumption with increasing percentage of ethanol in the fuel blend. Blends with biodiesel resulted in minor increases in CO emissions due to the engine being operated in the low and medium load regions over the WLTP. CO2 emissions as well as NOx emissions increased as a result of the high oxygen content in biodiesel which promoted better combustion. Fuel consumption increased for blends with biodiesel as a result from biodiesel’s lower heating value. All the statistical models describing the engine responses were significant and this demonstrated that a mixture DoE is suitable to quantify the effect of fuel blends on an engine’s emissions response. An optimised ternary blend of B2E9 was found to be suitable as a ’drop in’ fuel that will reduce harmful emissions of CO emissions by approximately 34%, NOx emissions by 10% and CO2 emissions by 21% for transient engine operating scenarios such as the WLTP drive cycle.

In this study, the response surface methodology (RSM) optimization technique was employed for investigating the impact of hydroxy gas (HHO) enriched diesel on performance, acoustics, smoke and exhaust gas emissions of the compression ignition (CI) engine. The engine was operated within the HHO flow rate range of 0–10 L/min and engine loads of 15%, 30%, 45%, 60% and 75%. The results disclosed that HHO concentration and engine load had a substantial influence on the response variables. Analysis of variance (ANOVA) results of developed quadratic models indicated the appropriate fit for all models. Moreover, the optimization of the user-defined historical design of an experiment identified an optimum HHO flow rate of 8 L/min and 41% engine load, with composite desirability of 0.733. The responses corresponding to optimal study factors were 25.44%, 0.315 kg/kWh, 117.73 ppm, 140.87 ppm, 99.37 dB, and 1.97% for brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), CO, HC, noise, and smoke, respectively. The absolute percentage errors (APEs) of RSM were predicted and experimental results were below 5%, which vouched for the reliable use of RSM for the prediction and optimization of acoustics and smoke and exhaust emission characteristics along with the performance of a CI engine.

The rise of crude oil price and the implications of exhaust emissions to the environment from combustion application call for a new reliable alternative fuel. A potential alternative fuel for compression ignition (C.I.) engine is the compressed natural gas (CNG). For C.I. engines to operate using CNG, or to be converted as a retrofitted CNG engine, further modifications are required. Previous works reported loss in brake power (BP) and increase in hydrocarbon (HC) emission for C.I. engine retrofitted with CNG fuelling. Verification of performance characteristics for CNG retrofitted engine through experimental analysis requires high cost and is very time consuming. Thus, a 1-Dimensional simulation software, GT-Power, was introduced in this study to reduce the experimental process and setup. A 4-cylinder medium duty C.I. engine (DE) and CNG retrofitted engine (RE) GT-Power models were used in this simulation work over various operational conditions: low, medium and high load conditions. As compared with DE model, results from RE model showed that RE model achieved an average 4.9% improvement for brake specific fuel consumption (BSFC) and loss in BP by 37.3%. For nitrogen oxides (NOX) and carbon dioxides (CO2) RE model predicted reduction of 48.1% (engine mode 1-9) and 33.4% (all engine modes), respectively. Moreover, RE produced 72.4% more carbon monoxide (CO) and 90.3% more HC emission.

The optimization of biodiesel production by using response surface methodology and its effect on compression ignition engine

The compression ignition and small displacement spark-ignition engines play an important role in the urban air pollution. In particular, vehicles equipped with compression ignition engines are widely used because of their higher performance and fuel efficiency with respect to the spark-ignition ones. Nevertheless, spark-ignition engines with low displacements are even more wide-spreading because of the lower fuel consumption and emissions. They are also used for two-wheeled vehicles, whose easier navigation makes them widely used in heavily congested areas. Their contribution on urban pollution is worsened by the fact that these vehicles have to comply with the Euro 3 standard; light vehicles have, instead, to fulfill the more restrictive Euro 6, which for the compression ignition and gasoline direct injection engines indicates for particle emissions also a number-based regulation. This article aims to characterize the effects of biofuels on engine emissions and performance of compression ignition and spark-ignition engines. The investigation was carried out on different class of engines. Direct injection and a port fuel injection spark-ignition engines fueled with ethanol and its blends, 10 v/v%, 50 v/v% and 85 v/v% of ethanol in gasoline. The compression ignition engine was equipped with a common rail injection system and was fueled with pure rapeseed methyl ester, representative of fatty acid methyl ester, and its blends in diesel, 20 v/v% and 50 v/v%. The gaseous emissions and the particle concentration were measured at the exhaust by means of conventional instruments. Particle size distribution function was measured in the range from 5.6 to 560 nm by means of an engine exhaust particle sizer. A comprehensive characterization of the particulate carbon was performed by means of optical diagnostics in the combustion chamber. In particular, two-dimensional images of flame evolution were detected and processed by two-color pyrometry technique to assess the in-cylinder soot formation and oxidation processes. For both the investigated spark-ignition and compression ignition engines, the use of biofuels shows a partial increase in the specific fuel consumption and a reduction of the soot particles emission. Nevertheless, a further effort on engine technology should be paid to balance the mass with the size and number of the particles.

Environmental pollution and depleting fossil fuel reserve is a matter of apprehension throughout the world. biodiesel is a potential renewable fuel which can be used as a replacement to diesel. Many researchers have found that the emission of nitrogen oxide (NOx) from biodiesel fuelled vehicle is more than that of conventional diesel fuelled vehicle. This NOx emission from the motor vehicles can be suitably reduced within the permissible limits using exhaust gas recirculation (EGR) technique. The current article is a review of biodiesel fuelled compression ignition (CI) engine with and without the use of EGR. It particularly emphasizes upon the performance, emission, and combustion characteristics. It reveals that use of biodiesel with exhaust gas recirculation reduced carbon monoxide (CO), hydrocarbon (HC), soot emission, and also NOx emission from CI engine. The brake thermal efficiency (BTE) is increased, and brake specific fuel consumption (BSFC) decreased slightly with exhaust gas recirculation implementation. In addition, the exhaust gas temperature is found to reduce significantly with EGR use.KeywordsVegetable oilBrake specific fuel consumptionBrake thermal efficiencyExhaust gas recirculationEmissions

The importance of biodiesel as a renewable and economically viable alternative to fossil diesel for applications in compression ignition (CI) engines has led to intense research in the field over the last two decades. This is predominantly due to the depletion of petroleum resources, and increasing awareness of environmental and health impacts from the combustion of fossil diesel. Biodiesel is favoured over other biofuels because of its compatibility with present day CI engines, with no further adjustments required to the core engine configurations when used in either neat or blended forms. Studies conducted to date on various CI engines fuelled with varying biodiesel types and blends under numerous test cycles have shown that key tailpipe pollutants, such as carbon monoxide, aromatics, sulphur oxides, unburnt hydrocarbons and particulate matters are potentially reduced. The effects of biodiesel on nitrogen oxides emission require further tests and validations. The improvement in most of the diesel emission species comes with a trade-off in a reduction of brake power and an increase in fuel consumption. Biodiesel’s lubricating properties are generally better than those of its fossil diesel counterpart, which result in an increased engine life. These substantial differences in engine-out responses between biodiesel and fossil diesel combustion are mainly attributed to the physical properties and chemical composition of the fuels. Despite the purported benefits, widespread adoption of biodiesel usage in CI engines is hindered by outstanding technical challenges, such as low temperature inoperability, storage instabilities, in-cylinder carbon deposition and fuel line corrosion. It is imperative that these issues are addressed appropriately to ensure that long-term biodiesel usage in CI engines does not negatively affect the overall engine durability. Possible solutions range from biodiesel fuel reformulation through feedstock choice and production technique, to the simple addition of fuel additives. This calls for a more strategic and comprehensive research effort internationally, with an overarching approach for co-ordinating sustainable exploitation and utilisation of biodiesel. This review examines the combustion quality, exhaust emissions and tribological impacts of biodiesel on CI engines, with specific focus on the influence of biodiesel’s physico-chemical properties. Ongoing efforts in mitigating problems related to engine operations due to biodiesel usage are addressed. Present day biodiesel production methods and emerging trends are also identified, with specific focus on the conventional transesterification process wherein factors affecting its yield are discussed.

A hybrid power generating system comprising a down draft gasifier and 5.5 kW diesel engine coupled to a 5 KVA AC generator was evaluated with biodiesel and high speed diesel (HSD) blend (B10) as well as producer gas and B10 in dual fuel mode (B10PG). The producer gas and biodiesel were produced from wood chips and jatropha oil, respectively. The performance and emission parameters of the system such as brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), overall efficiency of the system (OES), CO and CO2 were measured at variable loads (0, 50, 75 and 100% of load corresponding to load at maximum power) maintaining the rated engine speed (1500 rpm). Minimum BSFC and maximum BTE were observed at 100% engine loading and were 269.95 g/kWh, 31.86%; 346.57 g/kWh, 24% and 279.29 g/kWh, 31% for B10, B10PG and HSD, respectively. Reduction in calorific value of B10PG could be the reason for higher BSFC and lower BTE. The maximum OES was found to be 25.49%, 19.18% and 24.43% for B10, B10PG and HSD, respectively. As compared to HSD, CO and CO2 emissions for B10PG were found to be 18% higher and 6% lower, respectively whereas for B10, both these emissions were reduced by 9 and 2%, respectively. The increased CO emission with B10PG was due to less oxygen availability, which led to incomplete combustion. The developed system was found operating satisfactorily with dual fuel mode and on an average 70% of HSD replacement was possible.

In the present study, biodiesel is produced from neem oil by two-step esterification process. The neem oil ethyl ester (NOEE)–diesel blends are prepared by blending 10 to 100% NOEE with diesel. The blends containing 10 to 100% ester have their kinematic viscosity, cloud and pour point and flash and fire point compatible with diesel. The performance test of 4.4-kW diesel engine on fuel blends of neem oil biodiesel and diesel has carried out in terms of brake power, fuel consumption, brake-specific fuel consumption (BSFC) and brake thermal efficiency. Brake power of all the blends was found comparable with diesel, whereas fuel consumption, BSFC and brake thermal efficiency of 100% NOEE were found higher than the diesel. NOEE20 as fuel the brake thermal efficiency is found to be highest, and BSFC was found to be lowest on this blend. NOEE100 could be used as fuel with some modification in engine. Performance of NOEE20 is better than other blend so it could be used as future fuel.

Hydrogen enrichment effects on performance and emission characteristics of a diesel engine operated with diesel-soybean biodiesel blends with nanoparticle addition