Vezir Ayhan

New method to reduce NOx emissions of diesel engines: electronically controlled steam injection system

In this study, the electronically controlled water steam injection (ESI) system was introduced as a new method to reduce NOx emissions. In this system, the energy required for obtaining steam was supplied from exhaust gases. Throttling by injector, pressured and heated water, which is in the form of saturated liquid, becomes superheated steam; thus, the corrosion problem caused by condensation is prevented. It was determined in full load condition engine tests that NOx emissions reduce up to 33%, power and moment increase up to 3% and specific fuel consumption decrease up to 5%. When a steam injection system was tried in engine running with 20% biodiesel, it was determined that all the emission parameters, also including NOx, reduced. As a result, the ESI system is considered to be an important method that can be adapted easily in cruise ships, ferries sailing in continental waters and merchant ships in order to reduce NOx emissions.

The Effects of Different Fuels on Wear between Piston Ring and Cylinder

In internal combustion engines, mechanical friction occurs between engine components in contact with each other, leading to wear and important loss of efficiency. Mechanical energy absorbed by piston ring-cylinder pair in piston engines accounts for the largest portion of efficiency losses due to mechanical friction. Different engine lubrication regimes significantly affect wear and friction. In addition to selection of compatible materials, improvement of operational conditions and the properties of lubricants and fuels are of great importance to minimize wear. This study investigated the effects of oil, diesel fuel, oil + diesel fuel, and two different biodiesel fuels (SOME: sunflower oil methyl ester and TSOME: tobacco seed oil methyl ester) as engine lubricants and their effects on wear in piston ring-cylinder pair. The tests were carried out at different engine speeds and loads. Minimum wear occurred when using engine oil as lubricant, and maximum wear occurred when using diesel fuel as lubricant. The use of SOME and TSOME lubricant resulted in half the amount of engine wear, on average, compared to diesel.

Application of Taguchi’s methods to investigate factors affecting emissions of a diesel engine running with tobacco oil seed methyl ester

Different kinds of vegetable oils and their methyl/ethyl esters have been tested in diesel engines. However, studies reporting the effects of tobacco seed oil and Tobacco Seed Oil Methyl Ester (TSOME) on emissions of diesel engines are limited. One of the most important issues is to investigate parameters that affect the yield of biodiesel and their interactions on emissions of a diesel engine. The Taguchi method is a useful tool for this purpose. Two different catalysts (KOH and NaOH), four different blends (B10, B20, B50 and B100) and four engine speeds were used during full-load tests. Optimal catalyst type, engine speed and TSOME blends on exhaust emissions were determined using Taguchis technique. The Taguchi design method revealed that choosing right catalyst and the blend rate are important two factors in view of minimisation of pollutant emissions.

Effects of tobacco seed oil methyl ester on performance and exhaust emissions of diesel engine

Tobacco seed oil (TSO) was considered as a potential alternative fuel for compression ignition engines as the tobacco plant has high ecological tolerance and its farming can be realised on five different climatic regions in Turkey. In this study, the effects of TSO methyl ester (TSOME) on the performance and exhaust emissions of a single cylinder water cooled four-stroke diesel engine were experimentally investigated at full load conditions. The TSOME is mixed with diesel fuel in the mass rates of 10, 20, 50 and 100% (B10, B20, B50 and B100), and all the results tested with TSOME blends were compared with those of the standard diesel fuel. Comparing TSOME with standard diesel fuel, both the brake torque and the power of the engine were found higher 2·5% at B50. Hydrocarbon, CO and smoke emissions are measured lower, whereas the NOx emissions are found high.

Effects of water steam injection on direct injection diesel engine operating with partial loads

In the present study, a new method named ‘water steam injection’ is introduced as a measure to reduce NOx emissions. Required energy for producing water steam has been obtained from exhaust energy via the heat exchanger which was mounted to exhaust line of the engine. Main advantages of this method over the fumigation and emulsified fuel techniques, corrosive side effects of water on metallic surface have been eliminated by changing the phase of compressed hot water at 300 kPa and 133°C to superheated vapour conditions at 101·325 kPa and inlet temperature. Optimum steam rate was obtained as 20% from the performance and the exhaust emissions points of view. The test results obtained from the partial load conditions are given comparatively. In a wide speeds and engine loads intervals, while the effective brake power and the efficiency increased, specific fuel consumption and NOx emission decreased.

Design and Implementation of the Control System of an Internal Combustion Engine Test Unit

Accurate tests and performance analysis of engines are required to minimize measurement errors and so the use of the advanced test equipment is imperative. In other words, the reliable test results depend on the measurement of many parameters and recording the experimental data accurately which is depended on engine test unit. This study aims to design the control system of an internal combustion engine test unit. In the study, the performance parameters of an available internal combustion engine have been transferred to computer in real time. A data acquisition (DAQ) card has been used to transfer the experimental data to the computer. Also, a user interface has been developed for performing the necessary procedures by using LabVIEW. The dynamometer load, the fuel consumption, and the desired speed can easily be adjusted precisely by using DAQ card and the user interface during the engine test. Load, fuel consumption, and temperature values (the engine inlet-outlet, exhaust inlet-outlet, oil, and environment) can be seen on the interface and also these values can be recorded to the computer. It is expected that developed system will contribute both to the education of students and to the researchers’ studies and so it will eliminate a major lack.

Dietil Eter-Dizel Karışımlarının Direkt Enjeksiyonlu Bir Dizel Motorunun Performans ve Emisyonlarına Etkisi

Dietil eter (DEE) dizel motorlarinda kullanilabilecek yenilenebilir, yuksek setan sayili, makul seviyede enerji yogunlugu, yuksek oksijen icerigi, dusuk atesleme sicakligi ve yuksek ucuculuga sahip alternatif yakitlardan biridir. Bu calismada tek silindirli, direkt enjeksiyonlu (DI), su sogutmali bir dizel motorunda DEE-Dizel karisimlarinin motor performans ve emisyon karakteristiklerine etkisi deneysel olarak incelenmistir. DEE-dizel karimlari karisimlari kutlesel olarak, DEE3 (%3 DEE+%97 Dizel), DEE5 (%5 DEE) ve DEE7 (%7 DEE) hazirlanmistir. Deneysel calismalar dizel yakiti ve 3 farkli DEE-Dizel karisimlari motorda kullanilarak tam yuk sartlarinda 1000, 1300, 1600, 1900 ve 2000 d/d motor hizlarinda gerceklestirilmistir. Calismalar sonucunda motorda DEE karisimlari kullanildiginda standart motor verilerine gore motor dondurme momenti ve efektif gucunde azalma, ozgul yakit sarfiyati ve efektif verimde ise iyilesmelerin oldugu tespit edilmistir. Dizel motorlari icin buyuk problem olan NOx ve Is emisyonlarinda ise kayda deger oranda azalmalarin meydana geldigi saptanmistir.

Duvar akışlı bir partikül filtresindeki basınç kaybının deneysel ve nümerik incelenmesi

Dizel motorlarda yanmanin tam verimle gerceklesmemesi sonucunda zararli gazlar ve partikul madde cevreye atilmaktadir. Dizel motorlar fakir karisimda calistiklarindan dolayi azot oksit ve partikul madde emisyonlari fazladir. Dizel motorlarda, partikul madde emisyonlarini kontrol altina almak icin partikul filtreleri kullanilmaktadir. Partikul filtresi, icerisinde egzoz gazlarinin capraz akis yapmasini saglayarak kati ve sivi partikul madde emisyonlarini biriktirmek icin tasarlanmistir. Bu calismada, dizel partikul filtresinin basinc kaybi kurulan deney duzenegi uzerinde olculmustur. Olcumler sonucunda partikul filtresine ait gecirgenlik ve icsel kayip katsayisi hesaplanmistir. Sonlu elemanlar yazilimi kullanilarak basinc kaybi analizi gerceklestirilmistir. Calisma sonunda deneysel ve numerik sonuclar karsilastirmali olarak verilmistir.

HAVACILIKTA SERTİFİKASYON GEREKSİNİMLERİ VE 16G İLERİ DİNAMİK ÇARPIŞMA TESTİ

Uluslararasi hava sahasinda hizmet vermek isteyen firmalar, o ulkelerin cesitli guvenlik kriterlerini saglamakla yukumludurler. Bu sebeple, uretmis olduklari hava araclarini veya arac donanimlarini gereksinimlere gore cesitli testlere tabi tutarak sertifikasyon sureclerini tamamlamak zorundadirlar. Havacilik sektorunde basari, ucus guvenliginin diger bir degisle insan guvenliginin maksimum seviyede saglanmasiyla olculmektedir. Sektorde koltuk sertifikasyonu, ucagin acil inis sartlari altinda koltuga gelen cesitli yukleri karsilayabilme yetkinligine gore degerlendirilir. Bu calismada, sonlu elemanlar analizi yapilmis bir koltugun tasarim dogrulama aktivitesi yapilmistir. Federal Havacilik Idaresi ve Avrupa Hava Guvenligi ajansinin ortaklasa belirledikleri kriterlere gore uretilen koltuk icin tasarim dogrulama aktivitesi olan carpisma testlerinden birisi olan 16g ileri dinamik test kosullarinda gerceklestirilmistir. Elde edilen bulgular standartlarda tanimlanmis sinir degerlerle karsilastirilmistir.