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In this study, the biodiesel obtained from the waste olive oil by transesterification method has been mixed with a 30% of diesel fuel as volume and tested with a single cylinder direct injection diesel engine. The main purpose of this study is to obtain purer biodiesel from waste olive oil using methyl alcohol (CH3OH) and sodium hydroxide (NaOH) as catalyst in the transesterification method and research performance, combustion and emission characteristics in detail in a direct injection diesel engine. The combustion, engine performance and exhaust emission values have been also compared with diesel fuel. The test engine was operated at a constant speed of 2200 rpm and different engine loads such as 3.25 Nm, 7.5 Nm, 11.25 Nm, 18.75 Nm. According to the experimental results, the thermal efficiency of biodiesel is lower by about 1% to 5% than diesel. CO is lower about 37.5 % with biodiesel than that of diesel at 18.75 Nm. CO2 is higher 41% with biodiesel than diesel at 11.25 Nm. NOx was measured 9.5% higher than diesel fuel at 18.75 Nm. Soot emissions decreased by 37.5% compared to diesel.

In this numerical study, the effects of the premixed ratio, intake manifold pressure and intake air temperature on a four-cylinder, four-stroke, direct injection, low-compression-ratio gasoline engine, operated in reactivity-controlled compression ignition (RCCI) combustion mode at a constant engine speed of 1000 rpm, were investigated using Converge CFD software. The results of numerical analyses showed that the maximum in-cylinder pressure and heat release rate (HRR) increased and the combustion phase advanced depending on the rise in both intake manifold pressure and intake air temperature. The CA50 shifted by 18.5 °CA with an increment in the intake air temperature from 60 °C to 100 °C. It was observed that the combustion duration dropped from 44 °CA to 38 °CA upon boosting the intake manifold pressure from 103 kPa to 140 kPa. Moreover, a delay in the combustion phase occurred at a constant intake air temperature with an increasing premixed ratio. The maximum value of in-cylinder pressure was recorded as 36.15 bar (at 11 °CA aTDC) with the use of PRF20. Additionally, as the content of iso-octane in the fuel mixture was increased, combustion delay occurred, and the maximum value of in-cylinder temperature obtained was 11 °CA aTDC using PRF20 fuel at the earliest point. While HC and CO emissions reached the highest values at a 60 °C intake air temperature, NOx and soot emission values were detected at quite low levels at this temperature. The values of all these emissions increased with rising intake manifold pressure and reached their highest values at 140 kPa. In addition, while the highest HC and CO emission values were observed with the use of PRF60 fuel, the results revealed that the control of the combustion phase in the RCCI strategy is notably affected by the premixed ratio, intake manifold pressure and intake air temperature.

Additives are added to conventional fuels to ensure complete combustion of fuels, increase engine performance and reduce harmful emissions from vehicles. Hydrogen and oxygen-containing fuel additives added to fossil-based internal combustion engine fuels improve the properties of the fuels and reduce vehicle-related emissions. Evaluation of mixed fuels created by adding different types of alcohol and nano-sized additives to motor fuels as an alternative fuel in motor vehicles is among the most researched scientific studies recently. In this study, alcohol-gasoline fuels (E5, M5), NaBH4-alcohol-gasoline fuels (ES5, MS5), and pure gasoline were tested in a gasoline engine. Fuels used in engine tests; E5 fuel (5% by volume ethanol 95% gasoline blend), M5 fuel (5% by volume methanol 95% gasoline blend), ES5 fuel (5% by volume NaBH4-ethanol solution 95% gasoline blend), MS5 fuel (5% by volume NaBH4-methanol solution 95% gasoline mixture) and pure gasoline. In the experiments, brake thermal efficiency, engine torque, specific fuel consumption, and exhaust gas temperature were measured and compared with pure gasoline. Compared to gasoline, the exhaust gas temperatures of all blended fuels decreased. On the other hand, there was an increase in engine torque values, except for ES5 fuel. At the same time, there was an increase in both specific fuel consumption and brake thermal efficiency. When the CO and HC emission values of the blended fuels are compared with the gasoline fuel values, the highest reduction in CO emissions occurred in ES5 blended fuel with 65.53%, while the highest decrease in HC emission was realized in E5 fuel with 19.09%. On the other hand, when NOx and CO2 emissions of E5, M5, ES5, MS5 mixed fuels are compared with gasoline, NOx emissions are 12.63%, 28.37%, 19.65%, respectively; decreased by 36.03% but CO2 emissions increased by 8.51%, 30.46%, 34.48%, 25.95% respectively. © 2022 Elsevier Ltd

İçten yanmalı motorlarda güç bir milden alınmakta ve motor hareketi bu milin açısal hareketi ile tanımlanmaktadır. Bu hareket krank mekanizmalı motorlarda krank açısı adını alırken rhombic mekanizmalı motorlarda dişli açışını ifade etmektedir. Bu çalışmada, buji ile ateşlemeli dört zamanlı tek silindirli bir motor için krank hareket mekanizması ile buna alternatif olabilecek rhombic hareket mekanizmasının termodinamik olarak karşılaştırılması yapılmıştır. Hem rhombic hem de krank mekanizmasında maksimum silindir basıncı 371o’de elde edilmiştir. Krank mekanizmalı motorda maksimum silindir basıncı 63,1 bar iken rhombic mekanizmalı motorda maksimum silindir basıncının 64,5 bar olduğu görülmektedir. Rhombic mekanizmalı motorda bir çevrimde silindir duvarından kaybedilen ısı miktarı 15,27 J iken bu değer krank mekanizmalı motorda bir çevrim için 13,68 J olarak hesaplanmıştır.

The main disadvantages of HCCI engines are the knocking tendency at high engine loads, the challenge of the start of the combustion, control of the combustion phase, and the narrow operating range. In this study, we aimed to control the combustion processes in HCCI engines and to expand their working range by improving the fuel properties of fusel oil by the addition of diethyl ether. Thus, the variations in the in-cylinder pressure, rate of heat release, indicated mean effective pressure, start of combustion, combustion duration, CA50, indicated thermal efficiency, mean pressure rise rate, hydrocarbon and carbon monoxide emissions were investigated. It was observed that the in-cylinder pressure and rate of heat release were taken into advance and the test engine could be operated for a wider range by increasing the diethyl ether ratio in the blend. The indicated mean effective pressure increased by 67.5% with DEE40 fuel compared to the DEE80. Under the same operating conditions, HC and CO emissions decreased by 41.6% and 56.2%, in use of DEE40. Furthermore, the highest indicated thermal efficiency was obtained as 42.5% with DEE60 fuel. Maximum hydrocarbon and carbon monoxide emissions were observed with DEE80 fuel as 0.532% and 549 ppm, respectively.

Homojen dolgulu sıkıştırma ile ateşlemeli (HCCI) motorların yüksek termik verimleri ve düşük NOx emisyonları sebebiyle buji ile ateşlemeli (SI) ve sıkıştırma ile ateşlemeli (CI) motorlara göre önemli üstünlükleri bulunmaktadır. Ancak HCCI motorlarda yanma başlangıcının kontrol edilmesi oldukça zordur. Bu çalışmada, dört silindirli SI motordan dönüştürülmüş olan bir HCCI motoru kullanılmıştır. 373 K hava giriş sıcaklığı için, emme manifold basıncının HCCI yanma üzerine etkileri deneysel olarak incelenmiştir. Deney yakıtı olarak RON0, RON20 ve RON40 kullanılmıştır. Manifold basıncının artmasıyla yanma başlangıcının avansa alındığı gözlenmiştir. Ayrıca oktan sayısının değişiminin de yanma başlangıcı üzerine önemli etkileri olduğu gözlenmiştir. En yüksek indike termik verim RON40 yakıtı kullanımında, 120 kPa manifold basıncında %46,38 olarak kaydedilmiştir. Manifold basıncının artırılmasına bağlı olarak volümetrik verimin de artması maksimum silindir içi basınç ve ısı yayılımında artış sağlamıştır.

Çevresel kirlenmenin yol açtığı endişelerin giderek artması, içten yanmalı motorlarda daha temiz ve yenilenebilir yakıtların kullanımını arttırmıştır. Biyodizel pek çok ülkede dizel motorlarda alternatif yakıt olarak kullanılmaktadır. Bununla birlikte, dizel yakıtı ile karşılaştırıldığında biyodizelin yüksek viskozitesi ve buna bağlı olarak daha kötü atomizasyon karakteristiği kullanım alanının sınırlı kalmasına neden olmaktadır. Biyodizelin bu özelliklerinin iyileştirilebilmesi amacıyla çeşitli katkı maddeleri kullanımı üzerine araştırmalar gerçekleştirilmiştir. Bu çalışmada, karbon nanotüp katkı maddesinin, biyodizel-dizel yakıtı ile çalışan tek silindirli direkt enjeksiyonlu bir dizel motorunda performans ve emisyon karakteristiklerine etkileri incelenmiştir. Tam yükte motor hızına bağlı olarak gerçekleştirilen deneylerde, termik verim, motor gücü ve torku ile egzoz emisyonları incelenmiştir. Maksimum tork devrinde silindir içi basınç ve ısı dağılım oranı da analiz edilmiştir. Karbon nanotüp katkı maddesinin yanma başlangıcını öne aldığı ve termik verimi iyileştirdiği belirlenmiştir. Maksimum termik verim 100 ppm karbon nanotüp katkısı kullanıldığında %39,3 olarak elde edilmiştir. Karbon nanotüp katkı maddesinin CO, HC ve is emisyonlarını azalttığı ancak motor performansının iyileşmesine bağlı olarak NOx emisyonlarını arttırdığı belirlenmiştir. 100 ppm karbon nanotüp katkısının NOx emisyonlarını yaklaşık %11 arttırdığı, buna karşın CO, HC ve is emisyonları %20, %26 ve %7,9 oranında azalttığı tespit edilmiştir.

Homogeneous Charge compression ignition (HCCI) combustion mode is a very interesting new combustion model with high efficiency, low nitrogen oxide (NOx), and soot emissions. In the present investigation, the performance of an HCCI engine operated with three fuel ratios, i.e., 40% diethyl ether and 60% fusel oil (D40F60), 60% diethyl ether and 40% fusel oil (D60F40), and 80% diethyl ether and 20% fusel oil (D80F20), at different lambda values and engine speeds was assessed from exergy indicators. The results indicate that the lambda variation allows observing the best performance zones when operating with fuel blends. From the comparison of the exergy indicators, it is concluded that the highest engine efficiency is obtained when operating with D40F60 at a lambda between 2.1 and 2.2. However, it was determined that the increase of diethyl ether in the blend decreases the HCCI engine performance. Also, greater stability of performance was recorded when operating with D80F20. A higher exergy destruction rate is observed between lambda 3.4 and 3.9 when operating with D80F20. The exergetic efficiency values varied from 5.34% to 23.85%. According to the results obtained, the lowest and highest value of exergy efficiency was recorded for the D80F20 and D40F60, respectively.