Indian Journal of Engineering & Materials Science Vol. 21, April 2014, pp. 200-206 Investigation of the effects of civil aviation fuel Jet A1 blends on diesel engine performance and emission characteristics Hamit Solmaz a *, Hasan Yamık b , Yakup İçingür a & Alper Calam c a Automotive Engineering Department, Faculty of Technology, Gazi University, 06500, Teknikokullar, Ankara, Turkey b Engineering Faculty, Bilecik University, 06570, Bilecik, Turkey, c Automotive Technology Program, Atatürk Vocational High School, Gazi University, Ankara, Turkey Received 14 November 2012; accepted 10 January 2014 Study on use of aviation fuels in the internal combustion engines in road vehicles has been conducted for a long time. After the JP-8 is accepted as a single fuel on land and in the air (single fuel concept) by the North Atlantic Treaty Organization (NATO), the majority of these studies have focused on JP-8. For this reason, there is hardly any study on using the Jet A1, which is structurally very similar to the JP-8, in the internal combustion engine. However, in obligatory cases such as in periods of war, using the Jet A1 in the same way as the JP-8 in internal combustion engines may be required. In cold climates especially, the Jet A1 may gain strategic importance due to its very low freezing point. In this study, both the effects of the diesel and Jet A1 blends on engine performance and exhaust emissions in both the single cylinder, and the direct injection diesel engine have been examined. As a result, it has been determined that use of Jet A1 reduces engine torque to 5.85% and increases the specific fuel consumption to 8.77%. In addition, while there is an increase in smoke and carbon monoxide (CO) emissions 82% and 71.9%, respectively, there is a decrease in nitrogen oxide (NO x ) emissions by 29%. In conclusion, there is no positive effect in using the Jet A1 in the diesel engine except for the reduction of NO x emission and the decrease of the freezing point. Keywords: Jet A1, Aviation fuel, Diesel engine, Emission, Engine performance The process in the development of aviation fuels has continued for many years. Many studies have been conducted on aviation fuels in order to reduce costs, ease supplies, reduce the dependence on foreign oil supplies, and ensure reliability in military applications. For this purpose, using non-petroleum based energy sources such as coal; natural gas and biomass energy as aviation fuel have been investigated 1 . Jet engines are powered by kerosene, which consists of complex hydrocarbon mixtures with a boiling point of 145-300 o C. Jet fuels have a similar petroleum fraction to diesel and fuel oil. The most common aviation fuel for military engines is jet propulsion fuel 8 (JP-8), and for the civil aviation jet engines is Jet A1 2 . In 1988, NATO made a joint decision to use a single fuel in military aircraft and all land motor vehicles and equipment 3 . This idea is called a single fuel concept (SFC). The main purposes of this decision are elimination of the logistical problems in case of war and ensuring the more effective use of the NATO pipeline in peacetime. JP-8 military jet fuel, which is very similar to civil aviation fuel Jet A1, was chosen as the single fuel 3,4 . Diesel and JP-5 showed similar fuel consumption, with diesel consumption increasing at high engine loads. Ternary blends showed similar behavior. The blends with lower biodiesel content showed lower volumetric fuel consumption. Fuel sulfur content has an undesirable effect on smoke opacity 5 . The rapid development of today's modern diesel engines has enabled the use of diesel engines in general aviation vehicles. Diesel engine-powered aircrafts are reliable because of known fuel properties, low fuel consumption and high thermal efficiency relative to the gasoline engine. The main drawbacks of a diesel- engined aircraft are weight, cost, and appropriate fuel supply and fuel injection for a convenient diesel engine combustion characteristic. The fuel to be used in an aviation diesel engine is expected to have a good low temperature performance, sufficient lubrication properties, and an acceptable level of cetane number 6 . The selection of the JP-8 as a single fuel on land and air vehicles by NATO began the investigations related to using the JP-8 on diesel engine rather than diesel fuel. The diesel engines that had a mechanical distributor type —————— *Corresponding author (E-mail: hsolmaz@gazi.edu.tr)