Experimental investigation of gasoline fumigation in a turbocharged IDI diesel engine Z. Sahin a,⇑ , O. Durgun a , C. Bayram b a Karadeniz Technical University, Faculty of Engineering, Mechanical Eng. Dep., Trabzon, Turkey b Karadeniz Technical University, Trabzon Vocational School, Automotive Program, Trabzon, Turkey article info Article history: Received 10 June 2011 Received in revised form 14 September 2011 Accepted 19 September 2011 Available online 1 October 2011 Keywords: Gasoline fumigation NO x concentration Smoke index K Cost analysis Pre-chamber diesel engine abstract The current work examines experimentally the effects of gasoline fumigation (GF) on performance and exhaust emissions of a turbocharged indirect injection diesel engine. An elementary carburetor which main jet opening can be adjusted by a fine threaded screw was installed on the inlet pipe of the engine. Thus gasoline at desired amounts can be injected into inlet air and the engine operates mainly due to diesel principle. Results showed that effective power generally reduced and effective efficiency increased. Brake specific fuel consumption reduced and its decrement ratios are approximately at the levels of 5%. GF becomes economic for this engine and averagely 5% reduction in fuel cost was attained. NO x concen- tration decreased approximately at the levels of (5–10)%. Smoke index K reduced for up to (8–12)% GF and after this it began to increase. Its maximum reduction ratio was 20% for 8% GF at 2500 rpm. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Diesel engine, with up to 40% brake effective efficiency, is the most effective heat engine. For increasing its efficiency further and also reducing its exhaust emissions, various studies have been performed. Researches aiming to improve the combustion process constitute the most important examples of these studies. It is well known that by improving the combustion process, engine effi- ciency could be increased and exhaust emissions could be de- creased. Accordingly, recently, aiming to improve diesel engine combustion and performance, studies either on engine construc- tion or fuels have been continued. Some examples of these con- structive development are; improved combustion chambers, increased number and dimensions of valves, new injection equip- ments such as common-rail system and improved injection pro- cess, turbocharging systems especially in automotive diesel engines. As examples of studies on fuels, researches on the meth- ods of using of classical fuels more efficiently and also using of var- ious alternative fuels or fuel blends can be listed [1–3]. Various studies on the employing of the alternative fuels in die- sel engines are being continued. Alternative fuels can be used in diesel engines by applying four different methods such as blending, fumigation, dual fuel and direct using [4–6]. But of these, the meth- ods of blending and fumigation are frequently preferred. Liquid fuels such as alcohols (generally ethyl alcohol) and biodiesel are generally used by applying the methods of mixing or fumigation. There are some difficulties in the using of alcohols such as their lower cetan numbers and not mixing homogenously with diesel fuel and for these reasons mixing method is not generally preferred and some cetan improving additives are employed [4–6]. Conse- quently, for using alternative liquid fuels in diesel engines fumiga- tion method frequently applied. Here a suitable volatile light liquid fuel is simply added into intake air and it is not required to use sophisticated additional modifications and equipment. Also, by this way the inadequate effect of lower cetan number on ignition delay is prevented. Gaseous fuels, generally natural gas, are usually used by dual fuel method. In this method gaseous fuel is injected into intake air. Then this gaseous fuel–air mixture is burned by the aid of self ignition of the injected pilot diesel fuel. Here approx- imately 80% of the total heat energy is gained from gaseous fuel [7,8]. Recently di-methyl ether consists of another interesting gas- eous fuel which cetan number is higher than 45 and for this reason can be used in diesel engines by mixing method [9,10]. On the other hand, biodiesel can be employed in diesel engines either di- rectly or by mixing with diesel fuel. In the literature, usually using of 20% biodiesel–80% diesel fuel blends is recommended [11,12]. The objective of the current work is to investigate experimen- tally the effects of gasoline fumigation in an IDI diesel engine. As well known gasoline is not a renewable energy source and it con- stitutes the main conventional fuel for spark ignition engines. However it gives good results in respect of engine performance characteristics and exhaust emissions when it is used as an 0016-2361/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.fuel.2011.09.042 ⇑ Corresponding author. E-mail addresses: zsahin@ktu.edu.tr (Z. Sahin), odurgun@ktu.edu.tr (O. Durgun), bayramcoskun80@hotmail.com (C. Bayram). Fuel 95 (2012) 113–121 Contents lists available at SciVerse ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel