Research Octane Number (RON) and Motor Octane Number (MON) are measures of fuel anti-knocking performance. Minimum octane limits are specified by vehicle manufacturers to avoid knocking, which, in severe cases, may lead to power loss and engine damage. The octane requirement to avoid knocking is related to the engine type and engine operating conditions.

It is a measure of the fuel's combustion quality.

Cetane is an alkaline molecule that ignites very easily under compression, so it was assigned a cetane number of 100. All other hydrocarbons in diesel fuel are indexed to cetane as to how well they ignite under compression. The cetane number therefore measures how quickly the fuel starts to burn (auto-ignites) under diesel engine conditions. Since there are hundreds of components in diesel fuel, with each having a different cetane quality, the overall cetane number of the diesel is the average cetane quality of all the components.A fuel with a high cetane number starts to burn shortly after it is injected into the cylinder; it has a short ignition delay period. Conversely, a fuel with a low cetane number resists auto-ignition and has a longer ignition delay period.

Spark knock is the sound of abnormal fuel combustion. When a spark initiates combustion in a spark-ignition internal combustion engine, the flame front should fan out from the spark plug and travel across the combustion chamber rapidly and smoothly. If the last part of the air-fuel mixture ignites spontaneously (auto-ignites) before the flame front arrives, the sudden jump in the pressure in the cylinder creates the characteristic knocking or pinking sound. Knocking occurs because the octane of the fuel is below the antiknock requirement of the engine at that moment.

Just after World War I, American engineers made their choice. Putting profit above public health was nothing new for American industry, but it had never been done on such a massive scale and with such deadly results...

Lead compounds were added to the gasoline to increase the octane rating (anti-knock quality) and lubrication between the exhaust valves and the exhaust valve seats in cars with soft valve seats. If the octane rating of the fuel drops below the recommended level specified by cars manufacturers, the car engine may experience knocking (pinking). The unleaded gasoline being

One of 17 Bayway N.J. refinery workers who were victims of severe tetraethyl lead poisoning. They died "violently insane" in October of 1924As seen by the New York Journal-American

In 1925, Ethyl officials told the Public Health Service and the news media that there were no alternatives to leaded gasoline. Yet long before this picture was taken in Lincoln, Nebraska in 1933, alcohol gasoline blends were widely marketed in the Midwest and in Europe, and Ethyl's own researchers believed alcohol was "unquestionably the fuel of the future."

http://www.radford.edu/~wkovarik/ethylwar/nation.large.html

This chart shows the direct relationship between the dramatic drop in average American blood lead levels and the decrease in leaded gasoline use (red line) between 1976 and 1980.

  

Leaded gasoline was everywhere. It was used in 90 percent of all gasoline in the US between 1930 and 1976. It was so common that even Disney World -- where this image was taken -- put these apparently harmless little signs up in their antique gas station.

Henry Ford thought ethyl alcohol auto fuel would help American farmers find new markets and maintain their way of life.

Henry Ford thought ethyl alcohol auto fuel would help American farmers find new markets and maintain their way of life.

For many years, lead compounds have been added to gasoline in order to increase the octane rating in the fuel and give better engine performance. However, it has been found that vehicle exhaust emissions containing lead and other pollutants are posing a threat to human health and have long-term harmful effects on the environment.

Removing lead from the gasoline would provide a significant health and environmental benefit to Bahrain. It would also enable the use of advanced emission technologies (catalytic converter) for new cars imported in the future. The introduction is in line with the Government and GCC directives in this respect and is compatible with global trend to harmonize fuel specifications.

Occasional light knocking will not harm an engine. Heavy or prolonged knocking can result in loss of power, overheating of parts in the cylinder, and may end up causing engine damage.

2. What happens if I use the wrong octane gasoline in my vehicle?

1. Can knocking harm my engine?

Using gasoline with lower octane RON than that required by your vehicle will cause the engine to knock or, if the engine is equipped with a knock sensor, decrease the vehicle's power and acceleration. Using a gasoline with a RON higher than that required by your vehicle is unnecessary and a waste of money.

3. What cars can use unleaded gasoline?

All modern cars are suitable for unleaded gasoline except for some older cars.

4. How do I know if my car can run on unleaded gasoline?

First consult your vehicle's Owner Manual and the list. If, after doing this, you are still unsure whether your car could use unleaded gasoline, seek advice from your local vehicle dealer.

5. What octane should I use in my vehicle? Use a gasoline with the RON recommended by your vehicle manufacturer (refer to your vehicle's Owner's Manual). Using gasoline with a RON higher than that required to prevent knock will not improve a vehicle's performance or its power.

In many modern vehicles, the driver may never hear knocking when the RON of the gasoline is lower than the octane requirement of the engine because the engine is equipped with a knock sensor which temporarily retards spark timing to prevent knock. This adjustment may result in loss of power and acceleration. In this case, switching to a gasoline with a higher RON will improve performance and increase power.

6. How do I know which grade of gasoline to use?

You should refer to your vehicle Owner's Manual or check with the vehicle dealer.

7. Does my car need to be modified to run on unleaded gasoline?

Modern cars are designed to run on unleaded gasoline. Some old cars fitted with soft exhaust valve seats, require lubricity offered by the leaded gasoline. Lead replacement additive would be added to the gasoline, thus it would provide the necessary lubricity for the cars that need it. For the cars that have soft exhaust valves and need to use the higher octane offered, the lead replacement additive would be available as an "after-market" product and sold in bottles at service stations.

Hence, in both cases, no adjustment is required. However, if your car's engine starts knocking (pinking) for prolonged period after the use of the new fuel, please refer to your car dealer, as your car may need minor adjustment of the engine sparks timing to prevent the knocking.

8. If my car requires high octane leaded gasoline, what should I use? If your car requires the high octane Gasoline, you should continue to use unleaded gasoline and buy the lead replacement additive which will be made available in bottles at the service stations.

9. What happens if I accidentally fill unleaded gasoline into a car that cannot take it?

If you have used unleaded gasoline, then there is nothing to worry about, as the additive already added to the would provide the necessary protection.

If you have used the unleaded without adding any lead replacement additive, do not panic, as the valve seat recession would only occur in older engines under sustained speed and load.

10. Can vintage and classical cars use unleaded gasoline?

Antique cars are typically exposed to such light service that they are not expected to have valve seat problems. Thus using unleaded gasoline is not a problem. The customer will always have a choice of using lead replacement additives to provide the necessary protection either in bottles or by simply using the unleaded with the additives already added to it.

11. Unleaded Gasoline suitable for motorcycles, marine outboard engines and jet-skis? Unleaded gasoline is generally suitable for most motorcycles, marine outboard engines or jet-skis, except for a few which are equipped with older types of engines. Please refer to your equipment dealer for more information.