The use of natural gas in spark ignition engines and performance tests

Bu çalışmada benzin motorlarında alternatif yakıt olarak doğal gazın kullanılabilirliği araştırılmıştır. Dört silindirli bir benzin motoru doğal gaz motoruna dönüştürülmüş, deneyler benzin ve doğal gazla tam gaz kelebeği açıklığında, değişik yüklerde yapılmış, doğal gaz ve benzin kullanımının motor performansına etkileri incelenmiştir. Araştırma sonuçları doğal gazın benzin motorlarında alternatif yakıt olarak kullanılabileceğini göstermiştir.In this study, the use of natural gas by internal combustion engines as an alternative fuels was investigated. A four-cylinder spark ignition engine was modified to use natural gas and performance tests were conducted at the fully opened throttle position. The same tests were carried out by using gasoline and comparison is made. The results of study indicates that natural gas is able to be as an alternative fuel

EXAMINATION OF THE EFFECTS OF N-HEPTANE ADDITION TO THE CANOLA METHYL ESTER ON ENGINE PERFORMANCE AND COMBUSTION CHARACTERISTICS

Dizel motorları yüksek yüksek döndürme momenti, dayanıklılık ve ekonomik yakıt tüketimini sağlayan karayolu, tren, tarım, askeri, inşaat, madencilik, denizcilik, tahrik ve sabit elektrik üretimi gibi sektörlerde sıklıkla kullanılmaktadır. Petrol rezervlerinin azalması, sıkı emisyon düzenlemeleri, sera gazı emisyonlarını azaltmak ve içten yanmalı motorların verimini arttırabilmek için alternatif temiz ve yenilenebilir kaynaklar üzerinde çalışmalar yapılmaktadır. Bunların arasında biyodizel alternatif yakıtlardan birisidir ve motorda herhangi bir değişiklik olmadan kullanılabilmektedir. Daha iyi motor performansı için dizel yakıtı içine farklı katkı maddeleri harmanlanarak alternatif yöntemler denenmektedir. Biyodizelin yakıt kalitesini arttırmak için yakıt katkıları kullanılabilmektedir. Çünkü dizel motorlarının performansını, hem püskürtme sistemi özellikleri hem de püskürtülen yakıtın kalitesi önemli ölçüde etkilemektedir. Bu çalışmada; rafine edilmiş kanola yağından transesterifikasyon yöntemi ile biyodizel üretilmiş, üretilen biyodizele belirli oranlarda n-heptan katılmış ve motor deneyleri yapılmıştır. Yapılan deneyler sonucunda KYME-H4 yakıtında maksimum moment artışı %3.25 olurken maksimum güç artışı %2.48 olmuştur. Tüm yakıtlar için maksimum silindir gaz basınçları ve maksimum ısı yayılımı hemen hemen aynı krank açısında oluşmuştur. Çalışmada %4 n-heptan karışımı motor performans ve yanma özellikleri bakımından en iyi sonucu vermiştir.The diesel engines are widely used in industries like road transport, railway, agriculture, military, mining, construction, maritime and fixed electricity production for provide the high torque, durability and low fuel combustion.The reduction of oil reserves and strict emission regulations have led many researchers to work on alternative, clean and renewable sources in an effort to reduce greenhouse gases for emissions and to increase the efficiency of internal combustion engines. Among these, biodiesel is one of alternative fuels, and can be used without any changes in the engine. For a better performance of the engine, alternative methods are used by adding different additive substances to the diesel fuel. Because both features of injection systems and quality of injected fuel significantly affect the performance of diesel engine. In this study; refined rapeseed oil was produced from biodiesel by transesterification method, certain n-heptane was added to the produced biodiesel and the engine tests were performed. As a result of these conducted experiments; while maximum torque increase on the fuel KYME-H4 was 3.25%, the maximum power increase was 2.48%. Maximum gas pressure and maximum heat release for all fuel are formed in almost the same crank angle. In the study, 4% n-heptane mixture has given the best results in terms of engine performance and combustion characteristics

An experimental investigation on combustion and performance characteristics of supercharged HCCI operation in low compression ratio engine setting

This study investigates the effects of boost pressure on combustion and performance of an early direct injection homogenous charge compression ignition (HCCI) engine at a low compression ratio (CR). A 2.0 L, four-cylinder, four-stroke, gasoline direct injection engine was converted to operate in early direct injection HCCI mode. In addition, a supercharger unit was developed for engine boosting. The experiments were performed at different intake manifold absolute pressures (MAP) from 1.0 to 1.6 bar at different engine loads using n-heptane fuel. The effects of boost pressure were investigated on HCCI combustion and engine performance characteristics using volumetric efficiency, in-cylinder pressure, heat release rate (HRR), maximum in-cylinder pressure and gas temperature, CA50 (crank angle by which 50% of the fuel is burnt), combustion duration, apparent combustion efficiency, indicated mean effective pressure (IMEP), brake mean effective pressure (BMEP), friction mean effective pressure (FMEP), indicated thermal efficiency (ITE), brake thermal efficiency (BTE), heat loss, exergy of heat loss, coefficient of variation of IMEP (COVIMEP), maximum pressure rise rate (MPRR) and ringing intensity (RI). The experimental results showed that high-efficiency HCCI operation is feasible at an engine compression ratio as low as 9.2 once the engine variables are properly optimized and an appropriate level of supercharging is utilized. An increase in indicated thermal efficiency was seen as boost pressure increased. In addition, combustion phasing advanced by increasing boost pressure or increasing air–fuel equivalence ratio values. Combustion events with CA50 2–3 °CA aTDC show the highest thermal efficiency especially at low boost pressure conditions. In addition, the pressure rise rate and ringing intensity increased by increasing air–fuel equivalence ratio and MAP. The test results also showed that HCCI operating range can be extended with the increase of intake manifold pressure especially at high load limits