1. The effects of research octane number and fuel systems on the performance and emissions of a spark ignition engine: A study on Saudi Arabian RON91 and RON95 with port injection and direct injection systems Saud Bin Juwair, Taib Iskandar Mohamad, Ahmed Almaleki, Abdullah Alkudsi, Ibrahim Alshunaifi Water and Energy Research Institute, King Abdulaziz City of Science and Technology, P.O. Box 6086, Riyadh 11442, Saudi Arabia

2. The internal combustion engine, powering 90% of world vehicles, is the main driver in the transportation sector from which 20% of total world energy is consumed. The engine performance, thermal efficiency and pollutant emissions have a significant impact extending to the environment. Emissions from the transportation sector are considered a cause of Green House Gases (GHG’s) and account for more than 30% of global CO 2 emissions while consuming 63% of petroleum products. Motivations Local and global environmental concerns include increased emitted concentrations of carbon dioxide (CO 2 ), carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOX) that are threats to air quality and contribute to climatic warming.

3. Experimentally analyze the performance and emissions of a single cylinder, four-stroke spark ignition (SI) engine : Fuelled by two grades of gasoline used in Saudi Arabia, Research Octane Numbers (RON91 and RON95). Operated by two fuel delivery systems; port injection (PI) and direct injection (DI). Our research aims to :

4. Experimental setup

5. Lotus Single Cylinder Research Engine (SCRE) Lotus SCRE cylinder head Experimental setup Schematic diagram of experimental setup

6. Test procedures

7. A series of experiments were carried out using two gasoline fuels under varying engine speed from 1500 to 3500 rpm with 500 rpm increment at two engine loads 2.7 bar and 3.7 bar and for two fuel injection systems DI and PI. A series of experiments were carried out using two gasoline fuels under varying engine speed from 1500 to 3500 rpm with 500 rpm increment at two engine loads 2.7 bar and 3.7 bar and for two fuel injection systems DI and PI. In the PI system, fuel is injected at 2.3 bar and the start of injection timing (SOI) was at 360° BTDC. While in the DI system, the injection pressure was 100 bar and SOI was at 340° BTDC. Injection timing was controlled to maintain a stoichiometric mixture, and in both systems homogeneous mixture was formed In the PI system, fuel is injected at 2.3 bar and the start of injection timing (SOI) was at 360° BTDC. While in the DI system, the injection pressure was 100 bar and SOI was at 340° BTDC. Injection timing was controlled to maintain a stoichiometric mixture, and in both systems homogeneous mixture was formed Engine out data were recorded with maximum brake torque (MBT), that were achieved with ignition timings between 16° and 27° BTDC. Engine out data were recorded with maximum brake torque (MBT), that were achieved with ignition timings between 16° and 27° BTDC. The engine speed and load were set and measured. The engine speed and load were set and measured. Brake power, BSFC, brake thermal efficiency were computed. Brake power, BSFC, brake thermal efficiency were computed. The engine speed and load were set and measured. The engine speed and load were set and measured. Brake power, BSFC, brake thermal efficiency were computed. Brake power, BSFC, brake thermal efficiency were computed. Emission parameters of CO, THC, NOX and the exhaust gas temperature were recorded using the Horiba gas analyzer. Emission parameters of CO, THC, NOX and the exhaust gas temperature were recorded using the Horiba gas analyzer. The in-cylinder pressure was recorded for 100 cycles at a crank angle resolution 0.5°. The in-cylinder pressure was recorded for 100 cycles at a crank angle resolution 0.5°. Testprocedures Test procedures Prior to operating the engine with the tested fuels, the engine was operated using the new fuel for sufficient time to ensure the previous fuel was removed from the fuel system. Prior to operating the engine with the tested fuels, the engine was operated using the new fuel for sufficient time to ensure the previous fuel was removed from the fuel system.

8. Results Results Engine performance Engine performance Engine exhaust emissions Engine exhaust emissions

9. Engine performance

10. Variation of brake power against engine speed for RON91 and RON95 at two loads for PI and DI systems

11. Variation of thermal efficiency with engine speed for RON91 and RON95 at two loads for PI and DI systems

12. Variation of BSFC against engine speed for RON91 and RON95 at two loads for PI and DI systems

13. Combustion duration (10-90% MBF)

14. Engine exhaust emissions

15. Variation of NOx emissions with engine speed for RON91 and RON95 for RON91 and RON95 at 2.7bar load with PI and DI systems Variation of NOx emissions with engine speed for RON91 and RON95 for RON91 and RON95 at 3.7bar load with PI and DI systems

16. Variation of THC emissions with engine speed for RON91 and RON95 at 3.7 bar load for RON91 and RON95 at 3.7 bar load with PI and DI systems

17. The concentrations of CO emissions with engine speed for RON91 and RON95 at 3.7 bar load with PI and DI systems

19. Future work

20. Thank you