Cetane is becoming commonly heard, but many people still ask; ‘What is Cetane? Why do I want Cetane?’ Let’s consider three aspects of cetane to answer these questions.
WHAT IS CETANE NUMBER?
The Cetane Number or CN is a measurement of the length of time from fuel injection until the combustion process begins. It is NOT a measurement of fuel economy, power or combustion smoothness.
HOW DOES CETANE WORK?
Cetane improvement reduces the ignition delay period between the first fuel injection into the cylinder and start of combustion. In short, the higher CN, the easier fuel will combust in a compression setting (such as a diesel engine). The characteristic diesel ‘knock’ occurs when fuel that has been injected into the cylinder ignites after a delay - causing a late shock wave. Minimizing this delay results in less un-burned fuel in the cylinder and a less intense ‘knock’. Therefore higher CN fuel usually causes an engine to run smoother and quieter.
WHY DO I WANT HIGHER CETANE IN MY DIESEL FUEL?
By increasing the cetane number of your fuel you improve cold starts and reduce engine noise. By reducing the ignition delay cetane causes a more complete burn. Because of this it’s very common to see a MPG increase with a higher CN.
Generally, diesel engines operate well with a CN from 40 to 55. As mentioned earlier, fuels with a higher cetane number have shorter ignition delays, providing more time for the fuel combustion process to be completed. Hence, higher speed diesel engines operate more effectively with higher CN fuels. Interestingly many countries, such as Iceland, Norway, Switzerland and many other countries in Europe, require a minimum cetane rating of 51. Premium diesel fuel can have a CN as high as 60. The U.S. however, has a minimum CN rating at 40 and Premium diesel fuels are not required to have a higher cetane rating - it is left to the discretion of the supplier.
With these facts in mind Opti-Lube provides a number of diesel additives ranging from a 3-9 point cetane increase to help you ‘blend’ your way to premium diesel. See your diesel vehicle running at peak efficiency and grab some higher MPG today with Opti-Lube Diesel Fuel Additives.
