Makine Mühendisliği Bölümü Koleksiyonu

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https://hdl.handle.net/20.500.13055/47

Listeleniyor 1 - 20 / 42

Extreme lean hydrogen combustion in SI engines: NOx emissions and exergy destruction analysis
(Inderscience Enterprises Ltd., 2026) Karagöz, Yasin; Pusat, Şaban; Teksan, A. Emre; Tunçer, Erdal; Tetik, Tuğba
This study examines the effects of excess air coefficient (lambda) and late ignition timing on NOx emissions and exergy destruction in a hydrogen-fuelled internal combustion engine converted from a conventional diesel engine. Experiments are conducted at 1,500 rpm and 3.5 kW using two ignition timings [10 degrees and 0 degrees before top dead centre (BTDC)] and three excess air coefficients (lambda = 1.05, 2.15, and 3.75). Results indicate that late ignition (0 degrees BTDC) and ultra-lean operation (lambda = 3.75) significantly reduce NOx emissions. The impacts on brake thermal efficiency (BTE), brake specific energy consumption (BSEC), and exergy destruction are also evaluated.
Computational fluid dynamics-based aerodynamic performance evaluation of naca 64A206 airfoil using ansys fluent
(Euroasia Journal of Social Sciences & Humanities, 2026) Taş, Kerem Ali; Tanrıver, Kürşat; Ay, Mustafa
Aerodynamic performance evaluation of aircraft wings is a critical stage in aircraft design due to its direct influence on lift generation, flight stability, and overall efficiency. Computational Fluid Dynamics (CFD) methods provide an effective approach for predicting flow characteristics around airfoil geometries before experimental testing. Therefore, the objective of this study was to numerically investigate the aerodynamic behavior of the NACA 64A206 airfoil using ANSYS Fluent by evaluating velocity distribution, pressure variation, and lift coefficient characteristics.
Experimental investigation of a diesel engine fueled with diesel–DME blends and hydrogen/acetylene port injection: Energy, exergy, emission, and enviroeconomic analysis
(Elsevier, 2026) Demir, Usame; Özer, Salih; Gülcan, Halil Erdi; Tunçer, Erdal
This study experimentally evaluated the performance, emissions, energy, exergy, environmental, and envir oeconomic characteristics of a single-cylinder diesel engine fueled with diesel–dimethyl ether (DME) blends and port-injected acetylene and hydrogen. Experiments were conducted at 1800 rpm under loads of 3.2, 6.4, 7.9, and 12.8 Nm. Diesel was used as the reference fuel, while DME was blended with diesel at 10%, 20%, and 30% by volume. Acetylene and hydrogen were supplied individually or together at 5 and 10 L/h. Results showed that DME addition reduced fuel energy input by 12–28% and exergy destruction by 35–68%. Exergy efficiency increased from 13 to 14% for diesel to 26% with D70DME30 and to 28–30% in gas-assisted modes. Soot, CO, and HC emissions decreased significantly, while NO x increased moderately by 8–18%. Annual CO emissions and enviroeconomic impacts were reduced by up to 60%, demonstrating a viable transition strategy for cleaner and more efficient existing diesel engines.
Effects of sunflower oil biodiesel blends on diesel engine performance and emissions
(International Researcher Association, 2026) Tunçer, Erdal; Kaya, Yalçın; Akal, Dinçer
The environmental impacts and limited reserves of fossil fuels have increasingly highlighted the importance of alternative fuel sources. In this study, the effects of a sunflower oil biodiesel–diesel blend on the performance, fuel consumption, and exhaust emissions of a single-cylinder diesel engine were experimentally investigated. During the tests, pure diesel fuel (B0) and a blend containing 90% diesel and 10% sunflower biodiesel (B10) were evaluated under various load conditions. After the engine reached steady-state operating temperature, power output, fuel consumption, and exhaust emissions were measured. The findings indicate that the biodiesel blend does not adversely affect engine power and provides performance comparable to pure diesel at all load levels. While fuel consumption was similar at low and medium loads, a measurable reduction was observed at high loads when using the biodiesel blend, which is attributed to the improved combustion associated with the fuel’s higher oxygen content. Regarding exhaust emissions, the addition of biodiesel resulted in reductions in CO and HC emissions, whereas a slight increase in NOₓ emissions was observed. This increase is attributed to higher combustion temperatures and is considered manageable through appropriate emission-control strategies. In conclusion, the sunflower biodiesel blend enhances fuel efficiency while maintaining engine performance and offering environmental benefits; however, additional measures may be required to mitigate elevated NOₓ emissions.
Double materiality and SWOT analysis: A practical framework for environmental impact and sustainability assessment
(Inderscience, 2026) Yurtsever, Özlem; Çelik, Mustafa Cem; Uyar, Tanay Sıdkı
Double materiality is becoming a necessity in sustainability reporting, as it is essential for aligning organisational strategies with ESG priorities. This study proposes a framework to embed SWOT analysis within sustainability reporting, focusing on double materiality. By positioning SWOT as a bridge, the framework enables a holistic evaluation of internal capabilities and external ESG-related risks and opportunities. It encourages periodic updates to question sets, supporting an evolving, stakeholder-inclusive process aligned with annual reporting cycles. This approach offers organisations a practical reference to develop transparent, credible, and adaptable sustainability disclosures, reinforcing their strategic decision-making and compliance with increasingly complex reporting standards.
Effect of agricultural waste-derived biomethanol use on the performance and emission characteristics of a diesel engine
(Pen Academic Publishing Journals, 2026) Tunçer, Erdal
This study investigates the effects of wheat straw-derived biomethanol–diesel blends on the performance and emission characteristics of a diesel engine. Four fuel blends were tested: pure diesel (D100) and biomethanol blends at volumetric ratios of 5%, 10%, and 15% (B5, B10, B15). Experiments were conducted on a single-cylinder diesel engine under four load conditions (25%, 50%, 75%, and 100%). The results show that although the lower heating value of biomethanol increased specific fuel consumption (from 308 g/kWh to 346 g/kWh at full load), its high oxygen content and latent heat of vaporization significantly improved key emission parameters. Under full load, the B15 blend reduced exhaust gas temperature by 29 °C, soot emissions by 25%, and CO emissions by approximately 21% compared to D100. Conversely, nitrogen oxide (NOx) emissions increased from 2165 ppm to 2420 ppm, attributed to the ignition delay characteristics of biomethanol. Overall, blending biomethanol with diesel is an effective strategy for reducing soot and CO emissions; however, further optimization is required to address the trade-off between NOx emissions and fuel consumption.
The effect of swot analysis on the sustainability approach of a leading Turkish maritime construction company
(Renewable Energy Association of Turkey, 2026) Özil, Eralp; Yurtsever, Özlem; Çelik, Mustafa Cem; Uyar , Tanay Sıdkı; Saydam, Alper
The EU’s mandatory Corporate Sustainability Reporting Directive (CSRD) is based on the widely used GRI framework but significantly introduc es the concept of “dual materiality”, which requires companies to report both their impacts on society and the environment, and how sustainability issues af fect the company itself. This study practically demonstrates the importance of a SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis to be applied at the initial stage to reveal this “double materiality” when preparing a sustaina bility report for a company. In the context of the application in question, the de sign of the SWOT analysis, the objectives of the questions, the interpretation of the analysis results, and the effects of the findings on the sustainability report study and sustainability goals are presented.
Performance and emission characteristics of a single-cylinder diesel engine fueled with a 10% olive pomace oil– diesel blend
(Trakya University, 2025) Tunçer, Erdal; Kaya, Yalçın; Akal, Dinçer
This study investigates the effects of using a 10% olive pomace oil–diesel blend on the performance and emission characteristics of a single-cylinder diesel engine under varying load conditions. The blend was prepared by volumetrically mixing 10% olive pomace oil with standard diesel fuel. The engine was tested under four different load conditions: 25%, 50%, 75%, and 100% of full load capacity.The experimental results revealed that the engine power output decreased by a maximum of only 0.1 kW across all load conditions when compared to standard diesel. This minor reduction indicates that the blend maintains comparable engine performance. Fuel consumption increased by a maximum of 16 ml/h, which is a relatively small difference and within acceptable limits for alternative fuel use. In terms of emissions, carbon monoxide (CO) levels decreased slightly—by approximately 0.01%—across all load conditions, suggesting improved combustion efficiency. However, the reduction in CO was minimal. On the other hand, nitrogen oxides (NOₓ) emissions showed an increase, particularly at higher loads. A maximum increase of 160 ppm was recorded at 75% load, while other conditions showed moderate increases ranging from 55 to 65 ppm. Despite the slight rise in NOₓ emissions, the findings suggest that blending olive pomace oil with diesel at a 10% volumetric ratio can be a viable and sustainable alternative fuel option for diesel engines, with minimal impact on performance and moderate changes in emissions.
Experimental and thermodynamic analyses of a two-stroke UAV engine operated with gasoline–methanol blends
(Elsevier, 2026) Tunçer, Erdal
This study delineates experimental investigations and thermodynamic analyses conducted on a two-cylinder, two-stroke, air-cooled engine-standard for uncrewed aerial vehicles (UAVs)-oper ated with various gasoline–methanol fuel blends. Performance and emission metrics were ob tained at five thrust levels (5, 10, 15, 20, and 26 kg) utilizing five distinct fuel blends (M0, M10, M20, M30, and M40). The acquired data facilitated comprehensive evaluations of energy, exergy, and sustainability. At lower thrust levels, the minimal fuel consumption was observed with M0; at higher thrust levels, the minimum was recorded with M40. An increase in the methanol content within the fuel blends resulted in a notable reduction in CO2 emissions; for instance, at a thrust of 26 kg, CO2 emissions were 5.65% for M0 and 3.91% for M40. The highest efficiencies in terms of energy and exergy were achieved at a thrust of 15 kg across all fuel blends. Correspondingly, the maximum sustainability index was determined to be 1.39 for M40 at a thrust of 15 kg.
Energy, exergy and exergoeconomic analysis of a CI engine fuelled with waste frying oil biodiesel blended with waste tyre pyrolysis oil and higher alcohols (Heptanol and Octanol): A waste-to-energy approach
(Elsevier, 2026) Gülcan, Halil Erdi; Demirci, Oğuz Kürşat; Erol, Derviş; Tunçer, Erdal
This study evaluates a waste-to-energy diesel concept that co-valorises waste cooking oil and end-of-life tyres by formulating biodiesel–tyre pyrolysis oil blends with small additions of higher alcohols (1-heptanol and n-octa nol). Five fuels (B100, B90T10, B85T10H5, B85T10O5 and B80T10H5O5) were tested in a single-cylinder diesel engine. Engine performance, emissions and combined energy–exergy–exergoeconomic indicators were used to assess thermodynamic and economic viability. The quaternary blend B80T10H5O5 achieved the highest mean energy and exergy efficiencies (26.5 % and 24.6 %) and reduced brake-specific fuel consumption by about 5 % relative to neat biodiesel, owing to improved volatility and fuel oxygenation. This benefit was accompanied by higher NOx emissions and the largest specific exergy cost (≈1430 USD GJ− 1 ) at full load. By contrast, the binary blend B90T10 preserved biodiesel-like efficiency while lowering the specific exergy cost of shaft power by roughly 10 %, emerging as the most cost-effective option. Overall, modest shares of tyre pyrolysis oil (10 %) and long-chain alcohols (≤5 %) in waste-oil biodiesel can provide an attractive compromise between energy effi ciency, emissions and exergy-based cost, supporting circular-economy-oriented diesel combustion.
Techno-economic and environmental analyses of the use of ammonia-diesel dual fuel in compression ignition engines
(Elsevier, 2025) Karagöz, Yasin; Pusat, Şaban; Tunçer, Erdal; Teksan, A. Emre
In this study, a single-cylinder diesel engine, normally running on diesel fuel, was converted to ammonia-diesel dual fuel. The effects of ammonia fuel at different energy content levels (0 %, 5 %, 10 %, 15 %, and 20 %) were investigated on thermal efficiency, CO, THC, NOx, and smoke emissions. Subsequently, GWP (Global Warming Potential) emission values and tax calculations were performed. Furthermore, economic and exergy analyses were performed using the present value method for converting the engine to ammonia-diesel dual fuel. Finally, the economic analysis was re-conducted by calculating the carbon tax based on the GWP emission value. Based on the results, the lowest GWP emission values were obtained with the addition of ammonia at 10 % energy content.
Effects of blending different ratios of cottonseed oil with diesel fuel in a single-cylinder diesel engine
(AGBIOL, 2025) Tunçer, Erdal
The persistent reliance on internal combustion engines, particularly within the transportation sector, continues to pose significant environmental challenges due to the emission of exhaust gases. This issue has intensified global efforts to identify and develop alternative fuels that can mitigate greenhouse gas emissions associated with fossil fuel consumption. Concurrently, the gradual depletion of petroleum reserves and volatility in fuel prices have introduced economic sustainability concerns. In this experimental study, the impact of blending conventional diesel fuel with 10% and 20% cottonseed oil by volume on engine performance and exhaust emissions was evaluated using a single cylinder direct injection diesel engine. The results demonstrated that the addition of cottonseed oil did not significantly affect engine power output or brake specific fuel consumption. However, a notable decrease in carbon monoxide (CO) emissions was observed, accompanied by an increase in nitrogen oxides (NO) emissions with higher biodiesel ratios. These findings indicate that cottonseed oil–diesel blends up to 20% by volume can be considered a technically viable partial substitute for conventional diesel fuel in compression ignition engines, with tradeoffs in emission characteristics.
Kalıcı mıknatıslı senkron motorun modellemesi ve kontrolü
(Yıldız Teknik Üniversitesi, 2025) Miran, Ömer Faruk; Bayraktar, Meral; Tunçer, Erdal
Elektrikli araçlar (EV’ler), enerji verimliliği, çevreci ulaşım ve performans beklentilerini karşılamak amacıyla içten yanmalı motorlara alternatif olarak gelişmiştir. Kalıcı mıknatıslı senkron motorlar (PMSM), yüksek verimlilik, kompakt yapı ve geniş hız aralığı avantajları sayesinde EV uygulamalarında tercih edilmektedir. Tesla Model 3’te kullanılan İçten Mıknatıslı PMSM (IPMSM) yapısı, düşük hızda yüksek tork ve yüksek hızda verimli çalışma imkânı sunmaktadır.
Energy and exergy analysis of a cycle‑skipping strategy in an HCCI engine fueled with natural gas
(Springer Nature Link, 2025) Atak, Nisa Nur; Tunçer, Erdal; Doğan, Battal; Ünal, Kenan
Homogeneous charge compression ignition (HCCI) engines have attracted considerable interest due to its incorporation of features from both gasoline and diesel engines. In this study, the effects of cycle-skipping strategies on engine perfor mance, efficiency, and emissions in a natural gas-fired HCCI engine were investigated experimentally. Experiments were conducted under constant engine speed, at 25, 50, and 75% load levels, in the Normal, 3 Normal-1 Skip (3N1S), 2 Normal-1 Skip (2N1S), and 1 Normal-1 Skip (1N1S) cycle modes. Emissions, fuel consumption, energy–exergy flow, thermal losses, irreversibilities, entropy generation, thermal, and exergy efficiencies were calculated based on the experimental data. Under 50% engine load, the NOx emission in the 3N1S operating mode was measured at 1594 ppm, whereas it increased by 52.5% to 2431 ppm in the 2N1S mode. The correlation between cycle-skipping tactics and thermal efficiency was determined to be contingent upon engine load. In Normal and 3N1S modes, thermal efficiency generally improves with elevated engine loads, while the 2N1S and 1N1S modes provide superior performance at low to medium loads. At a constant 50% load, heat effi ciency in the 2N1S mode increased by 7.84% to reach 28.34% compared to the Normal mode. Additionally, thermodynamic analyses revealed that the 1N1S mode has the lowest entropy generation and the least irreversibility, at 0.021 kW/K. These results demonstrate that cycle-skipping strategies can be an effective tool for optimizing engine performance based on load.
Effect of adding soybean oil to diesel fuel on engine characteristics
(Trakya University, 2024) Akal, Dinçer; Tunçer, Erdal; Kaya, Yalçın; Beşer, Necmi; Efendioğlu, Ayşegül; Acar, Mustafa
Biodiesel fuels are seen as an important resource due to the environmental damage caused by exhaust emissions from the use of fossil fuels, the increase in global warming and the rise in oil prices. As an alternative, the use of biodiesel by blending certain percentages of biodiesel into diesel fuel is preferred due to both sustainability and some advantages. In this study, 10% soybean oil was added to the fuel used in a single-cylinder diesel engine and the changes in engine power, fuel consumption and exhaust emissions were experimentally investigated. According to the results of the study, it was observed that the engine power was almost the same with the addition of soybean oil to the diesel fuel, but there was an increase in exhaust emissions with some increase in fuel consumption. For this reason, it is clear that further experimental studies should be carried out by adding soybean oil with different characteristics and proportions to be used in diesel engines.
Enhancing the aerodynamic performance of a biomimetic wing with topography optimization
(Springer India, 2025) Çalışkan, Mehmet Erman; Sabırlı, Muhammet Üsame; Oruç, Emre; Karagöz, İrfan
This paper presents the optimization of the external shape of a model wing obtained from samara (maple seed) by means of biomimicry in order to improve its aerodynamic performance. Samaras, winged seeds of maples, have drawn attention in biomimetic design because of their high lift and low drag properties and autorotation capability. This makes them ideal for winged structures, which can operate in a wide range of wind conditions. This study aims to demonstrate that a samara wing can be modified using mathematical modelling, and different surface geometries can be created by making desired changes in the design parameters. Optimization of the topography of a samara wing model is presented using the results of computational fluid dynamics (CFD). The model wing was divided into three regions, and topography optimization was performed in five steps. Intermediate forms and final forms of the model are presented together with the CFD results. The final form of the model provided an aerodynamic performance increase of up to 28% depending on the angle of attack. In addition, as a result of these improvements, the biomimetic wing has simpler design parameters and a more applicable structure. These results suggest that aerodynamic performance can be enhanced by topography study on a biomimetic wing.
The effect of adding hydrogen peroxide to an engine used in unmanned aerial vehicles on fuel consumption, energy, exergy, and sustainability parameters
(Springer Nature Link, 2026) Özer, Salih; Tunçer, Erdal; Arslan, Ahmet; Doğan, Battal; Vural, Erdinç; Arslan, Ömer
This study explores the use of hydrogen peroxide solution—a novel additive not previously used in UAV engines—to improve the energy efficiency of commercially available unmanned aerial vehicles (UAVs). Different hydrogen peroxide ratios were blended with JP-8 fuel, a common UAV fuel, to boost engine performance and optimise operating conditions. The effects of these fuel blends on engine performance and emissions were thoroughly analysed at various UAV thrust levels (5 kg, 10 kg, 15 kg, 20 kg, and 25 kg). Energy, exergy, and sustainability assessments were conducted based on the findings. It was found that increasing engine thrust with the same fuel mixture resulted in higher system disorder and entropy production. For instance, at 5 kg thrust with the P20 fuel mixture, entropy generation was 0.046 kW/K, rising to 0.112 kW/K at 25 kg thrust. The study indicates that adding hydrogen peroxide to JP-8 fuel in UAVs decreases energy and exergy efficiencies. Specifically, at 15 kg thrust, JP-8's energy and exergy efficiencies were 18.54% and 17.37%, respectively. These values dropped to 15.50% and 14.59% with the P30 fuel blend. The sustainability index ranged from 1.226 to 1.070 across all fuel types.
Kalıcı mıknatıslı senkron motorun modellemesi ve kontrolü
(Yıldız Technical University Publishing, 2025) Miran, Ömer Faruk; Bayraktar, Meral; Tunçer, Erdal
Bu çalışmada, Tesla Model 3’te kullanılan İçten Mıknatıslı Senkron Motorun (IPMSM) matematiksel modeli oluşturulmuş ve alan yönlendirmeli kontrol (FOC) algoritması uygulanmıştır. Motorun kontrolü için klasik PI kontrol yapısı ve SVPWM (Space Vector PWM) modülasyonu kullanılarak hız ve akım regülasyonu gerçekleştirilmiştir.
Regülatör ağırlıklarının motor performansına etkisi
(Zenodo, 2025) Gündemin, Nevin; Aydoğdu, Ervanur; Tunçer, Erdal; Doğan, Battal
Dizel motorlar, yakıt dönüşüm verimlilikleri ve yüksek tork kapasiteleri sebebiyle farklı sektörlerde birincil güç kaynağı olarak tercih edilmektedir (Pachiannan ve diğ., 2025). İçten yanmalı motorlarda genellikle hidrokarbon içeren yakıt ile havanın yanması sonucunda enerji açığa çıkmaktadır (Görmez, 2020). Bu yanma olayı kumandalı (kontrollü) yanma, tutuşma gecikmesi ve ani yanma olarak 3 farklı aşama halinde ele alınmaktadır. Yanma aşamasının başlamasını sağlayan önemli parametrelerden biri ateşleme gecikmesidir (Miron ve diğ., 2021). Yakıtın püskürtülmeye başladığı zamandan silindir basıncının yüksek hızda arttığı zamana kadar geçen süreye ateşleme gecikmesi denilmektedir.
Motor püskürtme avansının motor performansına etkisi
(Zenodo, 2025) Uçkan, İrfan; Doğan, Battal; Tunçer, Erdal; Yılmaz, Gülten; Aydoğdu, Ervanur; Gündemin, Nevin
Sıkıştırma ateşlemeli motorların orta ve büyük araçlarda güç kaynağı olarak kullanılmasının sebepleri güç çıkışlarının, güvenilirliklerinin ve termal verimliliklerinin yüksek olmasıdır (Chen ve diğ., 2023). Sıkıştırma ateşlemeli bir motorda motor performansının, yanma safhalarının ve egzoz emisyonlarının oluşumunu etkileyen önemli parametrelerden birisi de ateşleme gecikmesinin süresidir (Kumar ve diğ., 2024). Enjeksiyonun başlamasıyla yanmanın başladığı zaman aralığı ateşleme gecikmesi olarak ifade edilmektedir. Enjektör iğnesinin yuvasından kalktığı noktadaki zaman genellikle enjektör başlangıcı olarak ele alınmaktadır. Yanmanın tam olarak nerede başladığını tespit edebilmek kolay değildir. Yanmanın başlangıcını tespit edebilmek için başvurulabilecek en iyi yöntem silindir basıncı için elde edilen verileri kullanarak krank açısına göre ısı yayma hızının eğimindeki değişimi gözlemlemektir (Kumar ve diğ., 2020).

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