er.02.2018.01.07

Aircraft engines worldwide rely on 100 low lead (100LL) aviation gasoline (AVGAS) for its safe operation. AVGAS basically contains high levels of tetraethyl lead (TEL) which boost its octane ring and assist in anti-knocking. Knock or detonation refers to the rapid explosion of the fuel instead of burning smoothly within the engine cylinders which can cause serious damage to the engine. The 100LL AVGAS is mainly utilized in aircraft engines in order to minimize the occurrence of this event. However, the leaded AVGAS is one of the major reasons for lead emission into the atmosphere. It contributes to serious health impacts among humans. The only solution for this problem is to make unleaded motor gasoline (MOGAS) as the substitute for leaded AVGAS for the use in reciprocating aviation engines as MOGAS is capable of giving a comparable performance to the AVGAS. However, the unleaded MOGAS has relatively lower octane rating compared to leaded AVGAS. This increases the tendency of the gasoline to ignite instantaneously during combustion stroke of the engine which increases the probability for the occurrence of engine detonation. Therefore, a research is carried out to study on the anti-knocking characteristics of these fuels. In this study, the full-scale engine detonation performance of the locally available unleaded MOGAS fuels are determined and compared to typical leaded AVGAS fuel. This is done by performing a full-scale Lycoming O-320-B2A reciprocating engine performance test to obtain comprehensive data on engine detonation. The fuels tested in this study are 100LL AVGAS, RON100 MOGAS, RON97 MOGAS and RON95 MOGAS. Each of these fuels is tested at a time in the Lycoming O-320-B2A engine and the knock data are recorded. From the experiment conducted, it can be concluded that the 100LL AVGAS has the best anti-knocking characteristics followed by RON100 MOGAS, RON97 MOGAS and lastly RON95 MOGAS.