Octane and cetane numbers measure a fuel's resistance to self-ignition or knocking. Octane numbers refer to gasoline's resistance to knocking, measured using two tests - the Research Octane Number (RON) and Motor Octane Number (MON). Cetane numbers refer to diesel fuel's ease of ignition, with higher numbers indicating easier ignition. Fuels like gasoline and diesel have different typical octane/cetane numbers and properties that affect their use in engines.

1. Octane & Cetane Numbers How they are related to fuel available commertially. Presented by – Ajit Thorat

2. Octane and Cetane number of fuel Fuel Research Octane Number (ROM) Motor Octane Number (MON) Cetane number Boiling point (ºC) Gasoline 92-98 80-90 0-5 37-205 Diesel -25 - 45-55 140-360 Methanol 106 92 5 65 Ethanol 107 89 5 79 Propane (LPG) 112 97 -2 -42.15 Methane (CNG) 120 120 0 -161.6

3. OCTANE NUMBER AND CETANE NUMBER Cetane number (diesel fuel) and octane number (gasoline) both measure the tendency of the fuel to ignite spontaneously. The cetane number refers to the eace with which desel fuel ignites easily at a relatively low temperature.

4. ROAD OCTANE NUMBER Research Octane Number (RON) and Motor Octane Number (MON) determined in single cylinder test engine in the laboratory Road Octane Number (RdON) measures anti-knock performance of multi-cylinder engine in an actual vehicle under road driving conditions

5. RON & MON Research Octane Number (RON) determined at 600 rpm engine speed with spark timing set at 13 degrees BTDC , represents mild driving conditions without consistent heavy loads Motor Octane Number (MON) determined at 900 rpm engine speed with spark timing adjusted inversely to compression ratio, represents severe, sustained high speed, high load driving.

6. CETANE NUMBERS Higher cetane related with: improved combustion improved cold starting reduced noise, white smoke, HC, CO and particulate emissions.

7. The most common type of automotive fuel Gasoline Diesel Fuel Diesel fuel contains more heat energy than gasoline by volume

8. Gasoline Octane Rating Measurement of the fuel’s ability to resist ignition caused by pressure and heat resists knock or ping Octane numbers give the antiknock value of gasoline

9. Gasoline Octane Rating

10. Cetane Rating Indicates the cold starting ability of diesel fuel Most automakers recommend a cetane rating of about 45 High cetane rating means the fuel will ignite easily from heat and pressure and burn quickly

11. Cetane Rating

12. Fuel Ignition Quality The ignition characteristics of the fuel affect the ignition delay. The ignition quality of a fuel is defined by its cetane number. 1) For low cetane fuels 2)For high cetane fuels