Fuel Consumption Values Research Articles

Analysis of Biomass Co-firing Combustion Test using Corn Cobs at Punagaya CFPP as A Green Energy Alternative

Abstract Indonesia is determined to reduce fossil fuels by 2060 set a national renewable energy mix target of 23% by 2025 and be free of fossil fuels by 2060. One of the PLN’s (a national electrical company in Indonesia) efforts to increase carbon emissions reduction and strengthen local new renewable energy is co-firing biomass on CFPP. Indonesia, which is located in a tropical area, has a large potential for biomass resources. Corn cob, one of the biomass types, has a big potential to replace coal as fuel in CFPP especially in Jeneponto Region, South Sulawesi. By utilizing corn cobs as a fuel with a co-firing mechanism, it can generate green energy. The methodology for assessing the corn cob co-firing combustion test’s performance at Punagaya CFPP is presented in this paper. It is based on a multi-criteria assessment designed to examine the technical, financial, and environmental effects of operating parameters with a mixture composition of 95% coal and 5% corn cobs at 70 MW load for 10 hours. From the test results in terms of operational aspects, the parameters have changed but it still in the normal operating range; FEGT increased by 5.3°C, bed temperature increased by 8.9°C, air chamber pressure decreased by 0.05 kPa, and total airflow decreased by 4.5 T/h. From the financial aspect, it has benefited from a decrease in the value of Specific Fuel Consumption (SFC), which is 0.014 kg/kWh compared to 100% coal. From the environmental aspect, the overall results of emission parameters are still by environmental quality standards and have decreased for NOx and SO2 parameters.

Research on the Energy Management Strategy of a Hybrid Tractor OS-ECVT Based on a Dynamic Programming Algorithm

The multi-degree-of-freedom characteristics of the planetary gear electronic continuously variable transmission (ECVT) configuration in series-parallel hybrid tractors impose more complex requirements for energy management strategies under variable load conditions. For a high-power hybrid tractor, this paper takes the hybrid tractor output-split (OS)-ECVT configuration as the research object and describes the principles of stepless transmission and power-splitting within the configuration. In order to improve the fuel economy of high-power hybrid tractors and the running status of power components, an energy management strategy focused on ploughing conditions based on the Bellman minimum dynamic programming (DP) algorithm is proposed in this paper. Second, equivalent fuel consumption is selected as the performance index for energy-saving control, and the solving principle of the energy management strategy based on the dynamic programming algorithm is established to facilitate the resolution process of the energy management strategy. Finally, the energy-saving control simulation is completed under ploughing conditions. The results show that compared with the energy management strategy based on the optimal operating line (OOL), the energy management strategy based on DP fully utilizes the benefits of low-cost electric energy and enables the hybrid power system to have a wider range of stepless transmission performance. In addition, the hybrid power system has the advantages of enhanced decoupling of speed and torque, higher efficiency, and more economical secondary energy conversion. As a result, the whole machine has enhanced power-split performance, greatly improving the running conditions of the power components. The equivalent fuel consumption values of the energy management strategies based on DP and OOL are about 3.1238 L and 4.2713 L, respectively. The equivalent fuel consumption based on DP is reduced by about 26.87%, which effectively improves the fuel efficiency of hybrid tractors.

Natural gas-fueled HCCI engine performance and emission analysis and comparison with SI and spark-assisted operations

ABSTRACT The homogeneous charge compression ignition (HCCI) engine is a promising technology in terms of both soot and NOx emission. Natural gas (NG) is advantageous especially for HCCI engines with its single stage combustion, low C/H ratio, and high octane number. Since the main challenge of HCCI technology is stability and transient operations, using HCCI for constant speed operations may be advantageous. In this study, a CI diesel engine, which is used as a generator at constant speed, was modified and converted into an NG-fuelled, SI engine. Then, the engine was supplied with NG for SI, HCCI, and spark-assisted HCCI experiments. Spark-assisted operations were executed by using 3, 5, and 7 degree ignition advance values to assist HCCI combustion. In-cylinder pressure variations, exhaust temperature, specific fuel consumption, and emission values were investigated for comparison of different strategies. Experimental results showed that using the HCCI strategy and retardation of ignition advance of spark-assisted HCCI operations reduced maximum pressure. Therefore, these strategies improved NOx emissions, while HC emissions were slightly increased. The spark-assisted HCCI strategy improves the stability of operation while increasing CO emission. The specific fuel consumption value of HCCI was slightly higher than that of SI operation, while it was lower than spark-assisted strategies.

Runway assignment optimisation model for Istanbul Airport considering multiple parallel runway operations

Abstract The aviation industry has rapidly developed in recent years. Due to the increased number of flight operations, managing air traffic has become essential. The air traffic management system aims to reduce the air traffic control workload and use existing resources more efficiently. This study proposed a new mixed integer linear programming model to minimise the total fuel consumption during taxi operations for the runway assignment problem, comparing the actual Istanbul Airport runway assignment data. The average taxi times are calculated using the 30,000-flight operations data for each arrival and departure taxi route. Also, 47 different aircraft types are obtained using the data for the fuel consumption calculation. The International Civil. Aviation Organisation (IACO) aircraft engine emissions databank provides the fuel consumption values for each aircraft according to engine type. This approach allows our model to calculate more realistic fuel consumption for taxi operations, as each aircraft engine type has a different fuel consumption value. The proposed model is implemented at Istanbul Airport, the busiest airport in Turkey, where multiple parallel runway operations are applied. The results showed that the proposed model reduced total fuel consumption for taxi operations between 6.6% and 14.4% compared to the actual Istanbul Airport runway assignment data.

Exploring direct injection strategies for improved combustion efficiency and emissions reduction in dual-fueled RCCI/compressed natural gas engine: A experimental survey

ABSTRACT The dwindling reserves of conventional fuels have spurred research into alternative options for diesel engine, particularly given diesel’s widespread use in global public transportation. Environmental concerns, notably regarding oxide of nitrogen (NOx), and smoke necessitate a shift toward alternative fuels. Diesel’s partial replacement with compressed natural gas in CI engines has shown promise in mitigating smoke and NOx emissions. The Present research utilized an RCCI engine, and employed combinations of Diesel+CNG dual-fuel to analyze how direct injection techniques affect performance, emission, and combustion features. Under full load conditions sans exhaust gas recirculation (EGR) 6 ms and 8 ms CNG yielded superior brake thermal efficiency (BTE) of 30.5% and 29.5% surpassing diesel’s 26%, although excessive CNG induction disrupted combustion, reducing efficiency, and introducing EGR, particularly at 10% enhanced BTE, with 6 ms CNG achieving a peak of 32.5%, slightly lower at 15% EGR with 30.9%. Diesel engine showcased diminishing brake-specific fuel consumption values with CNG supplementation, further mitigated by increased CNG concentrations and EGR rates. Peak combustion pressure decreased in the RCCI engine, with promising results seen at 6 ms CNG, comparable to pure diesel. EGR introduced pressure fluctuations, signifying a dilution effect on combustion, while the net heat release rate displayed increasing trends for CNG, stabilizing with EGR. NOx emissions, peaking in diesel engine, showed reductions with 6 ms CNG, further diminished with EGR implementation.

RSM based optimization of lambda and mixed fuel concentration parameters of an LTC mode engine

In this study, the effects of lambda and premixed ratio (PR) parameters on the response parameters of an engine operating in LTC (low temperature combusiton) mode is investigated and optimized using a hybrid method. RSM (response surface method), which is a combination of experimental and statistical method, is used as hybrid method. Depending on the variable parameters of lambda and PR, an experimental set was created with CCD (central composite design) and experiments were performed. The effects of the variable parameters on the response parameters were investigated and evaluated in detail on the generated counter graphs, optimization of the variable parameters was carried out. As lambda increased, a decrease in engine torque and thermal efficiency values, and improvements in CO2 and NOx emissions were observed. As PR increased, thermal efficiency and specific fuel consumption values worsened. The optimum premixed ratio was determined as 33.619 % and lambda value as 2.576. At these conditions, the values of response parameter were obtained as torque 12.115 Nm, BSFC 346.764 g/kWh, ITE 21.447 %, CA10 3.503, CA50 8.005, CO 0.169 %, HC 191.467 ppm, CO2 5.301 %, NOx 404.564 ppm and soot 12.687 %. The optimization desirability value was determined as 0.665 and strengthened the goodness of the optimization.

The Impact of Using Dimpled Surfaces on Ahmed Body on The Flow Characteristics

Vehicle aerodynamics which directly affects fuel consumption values in vehicles has great importance in terms of vehicle stability, acceleration ability, vehicle noise, and environmental pollution. Ahmed car model is one of the most important generic models, so this popular car model is widely used in the literature on fluid mechanics and vehicle aerodynamics studies. This study investigates the effect of a passive drag reduction technique which is known as dimple surface, on Ahmed car model with a 35° slant angle. The flow control methods were applied numerically also these methods were compared with similar works. Analysis made in this study were conducted with 2.4 million cell numbers and the maximum drag reduction is 3.5 % with optimum dimple surfaces. Moreover, the applicability and manufacturability factors were also evaluated in terms of implementing the dimpling modification to today’s current road vehicles.

Experimental investigation of new combustion chamber geometry modification on engine performance, emission and cylinder liner microstructure for a diesel engine

Abstract Emission values have been limited and some levels (Tier, EPA, NRE-v/c standards, etc.) must be compatible with human health and the environment. One of the most effective ways to achieve these levels is effective piston bowl geometry. The aim in designing the new combustion chamber was to provide a multiaxial distribution of the fuel in the bowl. In the study, the new combustion chamber was compared with the standard combustion chamber. Both chambers were fitted to the engine and the performance analysis was tested at different operation conditions. Then, 100-hour tests carried out to evaluate the effect of the piston bowl geometry on the surface of the cylinder liner by analyzing its microstructure. From the obtained results, the new combustion chamber geometry reduced HC, CO and soot emissions while NO emissions slightly increased compared to the standard combustion chamber. It decreased brake specific fuel consumption values by 4%, 5.53%, 7.02%, 6.4%, 5.55% and 5.18% for 1700, 1800, 1900, 2000, 2100 and 2200 rpm, respectively. Torque values increased at all engine speeds. When the cylinder liners were evaluated as a result of long-term endurance, there were clearly fewer abrasive wear lines on the cylinder liners of NCC compared to SCC.

Does Engine Oil Type Affect Fuel Consumption in Passenger Vehicles? A Two-Year Investigation

Reducing fuel consumption to decrease CO2 emissions has become a key development factor in the automotive industry. An effective way to decrease fuel consumption is to reduce the influence of various sources of energy loss. One way to increase engine efficiency is to use low-viscosity engine oils to reduce friction losses in the engine’s tribological systems. The aim of the article was to analyze the relationship between the type of engine oil and fuel consumption in a group of 12 passenger cars. This was a homogenous group of identical cars, equipped with the same engine, operated under very similar conditions. Three groups of engine oils (Revline, Total, Orlen) were tested in vehicles and stressed with comparable workloads. The experiment was conducted over two years (two stages of research). The collected results were presented using graphs and compared using statistical tests, split into two stages of research, with four seasonal temperature groups. The study provides a detailed description of fuel consumption differences taking into account variations in ambient temperature. The analyses were focused on finding answers to two research questions: does the type of engine oil affect the variation in combustion levels, and what is the variability of fuel consumption in different seasons due to the ambient temperature variability? Briefly, in both stages of the study, vehicles using Revline oil attained the highest average fuel consumption throughout the study period. Vehicles using Total oil showed similar results to those using Revline oil, with the difference in fuel consumption not as noticeable during warmer months. Conversely, vehicles using Orlen oil demonstrated the lowest fuel consumption values during colder months, but higher levels during warmer months.

Evaluation of Field Performance and Energy Consumption of a Medium-sized Combine Harvester for Harvesting Glutinous Rice in Malaysia

A medium-sized combine harvester has been recently deployed to harvest newly introduced high-value glutinous rice in Malaysia. Thus, efficient utilisation of combine harvesters during harvest is essential to minimise operating costs and grain loss. This study evaluated a medium-sized combine harvester’s performance and energy consumption for harvesting glutinous rice. The experiment was carried out on a one-hectare paddy field with three sub-plots using a central composite design (CCD). A time-motion study was conducted during the harvesting operation to determine the combine harvester’s performance parameters, which included field operating speed (FS), field efficiency (FE), theoretical field capacity (TFC), effective field capacity (EFC), grain throughput capacity (GTC), fuel consumption (FC) and field machine index (MI). The energy expended during the operation, which included machinery energy (ME), fuel energy (FCE), human energy (HE), and total energy (TE) input, were also computed. The average FS, FE, TFC, EFC, FC, and MI values were 2.42 km/h, 59.78%, 0.56 ha/h, 0.33 ha/h, 14.89 l/ha, and 0.30, respectively. The mean values of ME, FCE, HE, and TE were 305.35, 711.69, 3.62, and 1020.66 MJ/ha, respectively. The combine harvester achieved an average grain throughput capacity (GTC) of 1796.91 kg/h, demonstrating its effectiveness in handling glutinous rice harvesting. The average time distribution for the harvesting operation, such as effective harvesting time, turning/reversing time, and unloading time, was 1.85 h/ha, 0.38 h/ha, and 1.05 h/ha, respectively. Based on the results, it is concluded that the medium-sized combine harvester is technically and economically suitable for harvesting glutinous rice.

Biodiesel production from waste cooking oil using calcium oxide derived from scallop shell waste

Abstract Biodiesel is one of the alternative forms of diesel fuel and can be obtained using the transesterification process of waste cooking oil with a catalyst to accelerate the reaction. The heterogeneous catalyst from waste scallop shells is used due to its potential for being reused in the subsequent transesterification reactions. Heterogeneous catalysts can also be recycled, contributing to their environmentally friendly nature. This study aims to identify the performance of recycling a calcium oxide (CaO) catalyst from scallop shell waste on synthesis biodiesel. The method used is the transesterification method with the basic ingredients of waste cooking oil using a CaO catalyst. Then, after the transesterification process is complete, the catalyst is separated from the biodiesel and recycled to be reused in the transesterification process up to five times. The biodiesel samples obtained are identified for yield value, physico-chemical properties, thermal properties and performance. X-ray diffraction characterization results for the CaO catalyst show that it has a crystal size of 67.83 nm. Scanning electron microscope characterization shows that it has spherical particle shapes. Fourier transform infrared characterization shows the presence of Ca–O bonds. The highest biodiesel yield value of 74.23% is obtained in biodiesel Cycle 1. The flash point value of biodiesel samples ranges from 141.2°C to 149°C. Further, all of the biodiesel samples exhibit a cetane number of 75. The highest lower heating value of 38.22 MJ/kg is obtained in biodiesel Cycle 1 and the viscosity of the biodiesel samples ranges from 5.65 to 5.88 cSt. The density of the biodiesel samples ranges from 881.23 to 882.92 kg/m3. Besides, ester functional groups (C=O) and methyl functional groups have been successfully formed in all samples, with the methyl oleate compound observed as dominating the biodiesel samples. The cloud point value of the biodiesel samples ranges from 12°C to 13°C, and their pour point value ranges from 10°C to 12°C. The lead content in biodiesel is 0.8826 mg/kg. The lowest sulphur content is obtained from biodiesel Cycles 1 and 2 at 0.005%. Performance tests show that biodiesel has lower torque and brake power values than commercial diesel fuel and higher specific fuel consumption values than commercial diesel fuel.

Engine Calibration With Surrogate-Assisted Bilevel Evolutionary Algorithm.

Engine calibration problems are black-box optimization problems which are evaluation costly and most of them are constrained in the objective space. In these problems, decision variables may have different impacts on objectives and constraints, which could be detected by sensitivity analysis. Most existing surrogate-assisted evolutionary algorithms do not analyze variable sensitivity, thus, useless effort may be made on some less sensitive variables. This article proposes a surrogate-assisted bilevel evolutionary algorithm to solve a real-world engine calibration problem. Principal component analysis is performed to investigate the impact of variables on constraints and to divide decision variables into lower-level and upper-level variables. The lower-level aims at optimizing lower-level variables to make candidate solutions feasible, and the upper-level focuses on adjusting upper-level variables to optimize the objective. In addition, an ordinal-regression-based surrogate is adapted to estimate the ordinal landscape of solution feasibility. Computational studies on a gasoline engine model demonstrate that our algorithm is efficient in constraint handling and also achieves a smaller fuel consumption value than other state-of-the-art calibration methods.

Determination of fuel and power requirement of a branch shredder for different vineyard pruning wastes

The aim of the study was to determine the fuel consumption, torque and power requirement of a shredder machine used in the shredding of vineyard pruning wastes of different grape varieties. In the study, pruning wastes of Boğazkere, Öküzgözü and Şire grape cultivars, which are widely grown in Diyarbakır region, were used for tests. The experimens were carried out at three different rotation speeds of the engine (1500, 2000, 2500 rpm) and feeding rates (kg/h). Depending on these parameters fuel consumption, moment values and power were measured. The branch shredder machine has a 15 HP powerful. There are three chopper blades on the machine. The blades are driven by gasoline engine with the a belt and pulley system. According to obtained test results, per hour fuel consumption, power requirement and moment values increased for all three cultivars depending on the increase in the number of rotation of the blades, both at unloaded and under load. The highest fuel consumption was observed in Boğazkere cultivar, followed by Öküzgözü and Şire varieties, respectively. While the highest fuel consumption value was found as 1.535 kg/h in Boğazkere cultivar, the lowest value was obtained as 0.918 kg/h in Şire cultivar. A similar situation was obtained for power values. The power also increased with the increase in the number of blade revolutions While the highest power consumption value was obtained as 5.560 kW in Boğazkere cultivar, the lowest value was obtained as 3.326 kW in Şire cultivar. Here, there was no statistical difference between Boğazkere and Öküzgözü cultivars, but there was a significant difference between these cultivars and Şire cultivar. When the moment values of the cultivars were examined, the difference between cultivars was found to be very significant (p<0.01). The highest value was obtained as 26.26 Nm in Boğazkere variety, the variety with the highest Power and Fuel consumption value, while the lowest value was obtained as 15.65 Nm in Şire variety, which also had low fuel and power requirements.

Experimental study on effects of pilot injection mass strategy on combustion, Performance and emission characteristics of CRDI Engine

This experimental work reports how different pilot masses of biodiesel-blended fuel in Common Rail Direct Injection (CRDI) engines affect engine performance, combustion, and emissions. This experiment used 20MEWCO (20 % Methyl Esters of Waste Cooking Oil + 80 % Diesel) as the test fuel. Several parameters, such as timing and injection mass, affect how the CRDI system delivers fuel. In this work, the pilot injection mass was varied by 5 %, 7.5 %, and 10 %, keeping other factors such as injection pressure at 500 bar and the timing of the pilot and main injections at 36°Crank Angle before Top Dead Centre (bTDC) and 15°Crank Angle before Top Dead Centre (bTDC), respectively. This work reveals that when pilot mass is increased in steps of 2.5%, the combustion performance parameters like cylinder pressure, heat release rate and specific fuel consumption values decrease. Also, it gave off less smoke, carbon monoxide and hydrocarbons than regular diesel with more nitrous oxide. Also, it was found that at 10 % of the pilot mass, carbon monoxide, hydrocarbon, and smoke emissions were significantly reduced, with a slight rise in oxide of nitrogen emissions at the same time, without affecting the engine performance.

Control and Optimization of Pre-Transmission Parallel Hybrid Vehicle with Fuzzy Logic Method and Comparison with Conventional Rule Based Control Strategy

In this study, a model of a pre-transmission parallel hybrid vehicle was created in MATLAB/Simulink environment. A torque control strategy has been developed for the hybrid vehicle on the created model. The hybrid vehicle's torque control is provided by fuzzy logic and conventional rule-based control strategies. The control strategies of the hybrid vehicle have been developed based on four input parameters: accelerator and brake pedal position, battery state of charge and the operating mode of the electric motor. The regenerative braking system of the pre-transmission parallel hybrid vehicle has been provided with a fuzzy logic control strategy in both vehicle structures. In the fuzzy logic torque split controller, a control algorithm has been created in which the safety, performance and fuel consumption values of the vehicle meet at the optimum point. Under different driving cycle conditions, the effects of control strategies on engine operating points have been examined and average fuel consumption values have been obtained. In the control of the parallel hybrid vehicle with fuzzy logic method, it has been obtained that it provides 12.87%, 6.62%, 2.27% and 6.23% fuel savings under FTP-75, NEDC, EUDC and ECE-15 driving cycle conditions, respectively. It has been observed that the vehicle cannot provide sufficient performance in US06 driving cycle conditions with the use of conventional rule-based control strategy.

Improving natural gas supply chain profitability: A multi-methods optimization study

Developing effective optimization models to improve pipeline network profitability in oil and gas supply chains is one of the most promising research areas in this industry. Because of the substantial advantages natural gas networks’ operations have realized, this industry has become more competitive and eager to develop robust supply optimization decision models. However, although several models and techniques have been developed to reduce natural gas consumption, only very few studies have focused on comparing the performance of these models and the implications of the distinct optimization performances. Consequently, the generalizability of the research in the area is still problematic, representing a research area not sufficiently explored. Taking this into account, this paper compares the fuel consumption values in a French gas pipeline by analyzing the Genetic algorithms (GA), Generalized reduced gradient (GRG), and Ant colony optimization (ACO) models. Overall, our findings show significant differences in gas consumption when the ACO and GA are compared with the GRG technique. Furthermore, the findings indicate that ACOs are competitive with GA and GRG in computational efficiency in finding near-global optimized solutions. The article can assist decision-makers and policymakers in discovering the most profitable operational parameters to minimize gas consumption and increase the profitability of natural gas networks.

Model for the implementation of strategies for the solar energy use in a healthcare network

The implementation of strategies for solar energy use (SSEU) such as photovoltaic (PVS) and solar thermal systems (STS) in hospitals are alternatives for reducing conventional fuels consumption and CO2 emissions of energy-intensive buildings. However, there are barriers to the deployment of renewable energies in such buildings, which focus on technology costs and economic inventiveness. Thus, there is a need for tools that address the particularities of hospitals and that can provide new information to management authorities for the development of sustainable policies. The objective of this paper is to introduce a model for SSEU implementation in a healthcare network. For this purpose, a workflow is presented that allows the analysis of 3 levels in the health sector (healthcare network, hospital, and pavilion), where the aim is to: i. Identify hospitals with solar potential in a healthcare network, ii. Sectorize suitable surfaces in potential hospitals for SSEU implementation and iii. Determine the architectural, environmental, and economic feasibility of technologies. In this case, a healthcare network located in Micro-Región del Gran La Plata (Argentina) is selected as a case study. Based on the indexes developed, it was observed that potential hospitals are those located in peripheral areas. Then, linking critical fuel consumption values with solar radiation in the building envelope made it possible to detect suitable sectors for the installation of PVS on roofs and STS on north façades. Finally, state-subsidized energy and technology costs present an economic barrier to project implementation for hospital managers. However, by shifting the subsidy to the purchase of technologies, viable results could be achieved.

Evaluation of energy-exergy performance and sustainability index of a DI engine integrated with designed electromechanical EGR cooling system

Exhaust Gas Recirculation (EGR) system is a commonly used pretreatment technique to improve pollutant emissions from modern diesel engines. Recently, the EGR cooling strategy focuses on improving combustion stability, NOx emission and fuel consumption values by controlling oxygen dilution, in-cylinder and exhaust gas temperatures. However, there are not enough studies focusing on energy and exergy analysis to improve the deterioration caused by hot EGR gas in engine performance and energy distributions. Therefore, in this study, classical and electronically controlled external EGR cooling systems are designed. The present study investigates the effect of the various EGR rates and EGRout gas temperatures on classical/electromechanics EGR cooling systems in a DI diesel engine and reveals the effects of energy-exergy distributions on each other and the sustainability index (SI) perspective. The tests are performed with various EGR rates (5%, 10%, 15%) and EGRout gas temperatures (75 °C, 90 °C, 110 °C) at 1700 and 2000 rpm. At 1700 rpm test conditions, the highest thermal-exergetic efficiencies for low and high load are recorded at 15% EGR rate-75 °C EGRout gas temperature and 5% EGR rate-75 °C EGRout gas temperature, respectively. At 2000 rpm test conditions, the highest thermal-exergetic efficiencies for low and high load are achieved at 15% EGR rate-110 °C EGRout gas temperature and 5% EGR rate-90 °C EGRout gas temperature, respectively. The main findings show that the EGR rate rather than the EGRout gas temperature has a more dominant effect on the in-cylinder combustion performance and thermal-exergetic efficiency. While the increase in the EGR rate from 5% to 15% contributes positively to the thermal-exergetic efficiency and SI performance at low engine load, the opposite is observed at high load. The study recommends that the EGR rate and EGRout gas temperature should be chosen at the optimum level for the engine performance and energy efficiency.

Experimental investigation for the different blend ratios of kerosene with diesel on the exergetic performance of a small-scale turbojet engine for UAV missions

The main purpose of this study is to experimentally analyze the exergetic performance of a small-scale turbojet engine that can be used in unmanned aerial vehicles (UAVs) when different blend ratios of kerosene with diesel are necessary, like in extraordinary situations. Comparative analysis was performed to understand the effects of the use of various diesel rates on the jet engine’s performance. To maintain air operations when refueling is required, easy-reachable fuels can help for short but important periods. In cases when there is a need for the use of a quick-reachable fuel in war conditions, diesel may be a suitable fuel. The UAV turbojet engine consists of a radial compressor, an annular combustion chamber, an axial turbine, and a propelling nozzle. The compressor, combustion chamber, turbine, and nozzle were evaluated by using the exergy analysis method. The performance parameters to evaluate the turbojet engine components were specific fuel consumption, thrust, overall exergy efficiency, and air-to-fuel ratio. The turbojet engine was operated at different throttle settings to monitor the changes in the performance parameters. As a result of using different kerosene and diesel fuel blends at different throttle settings, it was observed that the findings were consistent. Generally, the maximum exergy efficiencies took place in the turbine except for the full throttle settings. The minimum exergy efficiencies belonged to the nozzle. It was observed that irrespective of which fuel blend was used, thrust specific fuel consumption values decreased as the throttle setting increased. On the other hand, thrust values, overall exergy efficiencies, and air-to-fuel ratios had an increasing trend as the throttle setting was increased.

Investigation of ketal-acetin mixture synthesized from glycerol as a renewable additive for gasoline-ethanol fuel blend: Physicochemical characterization and engine combustion, performance, and emission assessment

Fossil fuel combustion in internal combustion engines, especially gasoline engines, leads to urban air pollution and contributes to greenhouse gas emissions and climate change. Ethanol has long been considered a promising option to replace gasoline and reduce the amount of associated pollution. Despite its advantages of improving fuel combustion and reducing pollutants, increasing nitrogen oxide emission is an environmental issue caused by using a high percentage of ethanol in fuel. Another challenge the biofuel industry faces is the crude glycerol produced as a by-product of the biodiesel production process, which requires a high-technology purification line, restricting biodiesel production capacity. Considering both challenges, the present study valorized glycerol into a fuel bio-additive, i.e., a ketal-acetin mixture, and developed gasoline-ethanol fuel formulations containing the synthesized bio-additive. To this end, the additive was synthesized through two-stage reactions, i.e., synthesizing acetin mixture using acetic acid and then ketalizing using acetone at specific reaction conditions. Afterward, different fuel samples were analyzed through a physicochemical study and tested in a spark-ignition engine setup. According to the results observed, adding a 2.5% ketal-acetin mixture to gasoline fuel containing 20% ethanol could improve brake power and thermal efficiency, especially at higher engine speeds. At higher engine speeds, there was a decrease in the brake specific fuel consumption values of the fuel sample containing a 2.5% ketal-acetin mixture. At the same time, besides maintaining the positive effects of ethanol presence in reducing engine exhaust emissions such as carbon monoxide and unburned hydrocarbons, this fuel blend reduced nitrogen oxides mean values by 34.5%.