What is the significance of octane number and cetane number of a fuel What are the structural features of hydrocarbons in petrol and diesel?
Octane number shows the ability of a fuel to resist knock (pre-ignition of the fuel) in the Gasoline Engine that needs high compression ratios. the Cetane number is measures of ignition delay. Higher the cetane number of fuel the shorter the ignition delay, the least time it take to burn.
What do you mean by octane number and cetane number write their significance?
Octane number is a value used to rate the fuel’s resistance to knocking. Cetane number is a measurement of the ignition properties of a fuel.
What is the significance of cetane number?
The cetane number (CN) is an indicator of the ignitibility of diesel fuels. It provides information about the ignition delay, i.e. the speed of self-ignition of diesel fuel when injected into hot air through the fuel injector.
What does an octane number indicate?
Octane ratings are measures of fuel stability. These ratings are based on the pressure at which a fuel will spontaneously combust (auto-ignite) in a testing engine.
What is the octane number of diesel?
Examples
| Fuel | RON | MON |
|---|---|---|
| hexadecane | < −30 | |
| n-octane | −20 | −17 |
| n-heptane (RON and MON 0 by definition) | 0 | 0 |
| diesel fuel | 15–25 |
What is the difference between cetane number and cetane index?
Cetane number is the most important and universally accepted ignition quality test. The cetane number test uses a standard single cylinder variable compression ratio diesel engine. Cetane index is a calculated value, which is derived from relatively easily measured fuel properties.
What is the difference between octane number and cetane number?
The main difference between cetane and octane ratings is that the octane rating represents how well a fuel can resist pre-ignition due to compression—ensuring the fuel ignites only from a spark from the spark plug. However, the cetane number measures the delay in the ignition time of the fuel.
What is the octane of diesel?
Diesel fuel has an octane rating of 25-40. Mixing 2% diesel fuel into gasoline will lower the overall octane rating by 1 point.
What is the difference between cetane index and cetane number?
The cetane number test uses a standard single cylinder variable compression ratio diesel engine. Cetane index is a calculated value, which is derived from relatively easily measured fuel properties. Thus, cetane index can provide a measure of fuel ignition quality without the need to run the costly cetane number test.
How does cetane number increase in diesel?
Innospec can also provide a nitrogen-free Cetane Number Improver, CI-0808. This additive can be used to increase the Cetane Number of diesel fuels without increasing the fuel nitrogen content. CI-0808 is a blend of Di-tert-butyl peroxide in solvent and is typically used at 0.05% to 0.50% volume.
Why is a high octane number good?
An octane rating is simply a measure of how heat resistant a fuel is in order to prevent knocking. In other words, octane doesn’t enhance combustion — it prevents the air-fuel mixture inside an engine from igniting before it’s supposed to. The higher a fuel’s octane, the more resistant it is to knocking.
How is cetane number of diesel calculated?
In the ASTM D613 test, the cetane number of a diesel fuel is determined by comparing its ignition delay in the standard CFR test engine with those for blends of reference fuels of known cetane number.
What is the difference between octane and cetane number?
For example, octane 92 is the fuel that is composed of 92% of isooctane along with 8% of heptane. Therefore, if the octane number is high, it is a good fuel to be used in an engine. Cetane number is the measure of the delay of the ignition of a fuel.
What is cetane number in diesel engine?
Cetane Number measures the ignition delay of the fuel in the diesel engine. When Cetane number is higher, the ignition delay is short and the fuel having high Cetane number is considered as the Ideal fuel in the diesel engine. 2. Based on Type of fuel: The higher number between both scales define high quality.
What is the octane number of n-hexadecane?
Commonly octane number of fuel ranges from 87 to 95 in gasoline fuel. Cetane rating is measured according to the ignition of the cetane. N-hexadecane consists maximum cetane number which is the hundred and 1-methylnaphthalene has minimum cetane number zero.
What is the octane number of fuel in gasoline fuel?
Commonly octane number of fuel ranges from 87 to 95 in gasoline fuel. Cetane rating is measured according to the ignition of the cetane. N-hexadecane consists maximum cetane number which is the hundred and 1-methylnaphthalene has minimum cetane number zero. It ranges from 30 to 35, fuel exceeding this number is known as poor fuel.