A Study to Assess the Effect of Octane on Vehicle Emissions

Market fuels inevitably differ in composition from the standard reference fuel used for vehicle emission validation. In South Africa, where almost half the vehicle parc operates at an altitude of about 1500 meters, the lowered volatility and octane requirement further differentiates the fuel composition. The aim of this project was to assess the impact of fuel compositional deviations and research octane number (RON) deviations on regulated vehicle emissions. The result shows that fuel RON and the fuel compositional changes associated with different RON grades do not significantly affect the regulated spark-ignited (SI) vehicle emissions.