Influence of Octane Number Rating on Performance, Emission and Combustion Characteristics in Spark Ignition Engine

Yew Heng Teoh; Heoy Geok How; Kok Hwa Yu; Hun Guan Chuah; Wai Loon Yin

Authors

Yew Heng Teoh School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus,14300 Nibong Tebal, Penang, Malaysia
Heoy Geok How Department of Engineering, School of Engineering, Computing and Built Environment, KDU Penang University College, 32, Jalan Anson, 10400 Georgetown, Penang, Malaysia
Kok Hwa Yu School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus,14300 Nibong Tebal, Penang, Malaysia
Hun Guan Chuah Department of Engineering, School of Engineering, Computing and Built Environment, KDU Penang University College, 32, Jalan Anson, 10400 Georgetown, Penang, Malaysia
Wai Loon Yin Department of Engineering, School of Engineering, Computing and Built Environment, KDU Penang University College, 32, Jalan Anson, 10400 Georgetown, Penang, Malaysia

Keywords:

RON, combustion , NOx, SI engine

Abstract

Recently, the world crude oil price grows continuously and the increase in gasoline price is affected the gasoline consumer. In Malaysia, the gasoline fuel price per litre for RON 97 and RON 100 are higher than RON 95 at all times. In general, the influence of different research octane number (RON) fuels on engine performance remains unknown to the public. This research aimed to experimentally study the effect of RON of the commercially available gasoline fuels on the performance, emission and combustion characteristic of a spark ignition (SI) engine. Gasoline fuels with RON 97 and RON 100 were tested and benchmarked with RON 95 as baseline on a single-cylinder, air cooled, four-stroke spark-ignition gasoline engine. The engine speed was varied from 1600 to 3200 rpm with 400 rpm increment under full throttle conditions. Generally, the results indicated that higher octane fuel reduced the emission of CO and HC, while lower octane fuels caused a lower emission of CO2 and NOx. Besides, a higher cylinder pressure and heat release rate were achieved with lower octane fuel of RON95. Overall, the experimental results suggested that a moderate octane number fuel of RON 97 is a good candidate for operating on this engine with consideration is being focused on the balance between performance, emissions and combustion characteristics.