The Story on Cetane

03 Mar 2020, Posted by McPherson Oil in Industry Information

What is cetane?

The cetane number (CN) of diesel fuel is a measure of the ignition quality of the fuel based on the ignition delay in an engine. Ignition delay measures the time between the start of injection and the start of combustion. In order for diesel fuel to ignite, it must go through the following steps:

  1. Diesel injection into the engine
  2. Atomization
  3. Vaporization
  4. Fuel – air mixing
  5. Ignition & combustion processes

The higher the cetane number of diesel fuel, the shorter the time it takes for the fuel-air mixture to ignite.

Limited Benefits in Today’s Engines

Having a diesel fuel with higher cetane comes with some limited benefits:

  • Better cold start in cold weather
  • Reduced noise from the engine

The benefits of higher cetane fuels are limited in modern diesel engines for many reasons.

  • Diesel engines in the U.S. are calibrated and optimized for ASTM D975 diesel fuel (≥40 CN)
  • Modern diesel engines with high-pressure common rail systems have multiple injection capability, which minimizes the impact of shorter ignition delay
  • Heavy-duty diesel engines run at lower engine speeds and are less sensitive to ignition delay
  • No performance or fuel efficiency impact after warm-up


Proven Benefits of Mobil Diesel Efficient

Today’s diesel engines have sophisticated fuel systems that rely heavily on clean injectors. Deposit-laden injectors will have a negative impact on the efficiency and emissions of an engine throughout its whole operating cycle – not just at start-up on a cold winter day!

While it does not contain a cetane improver, the patented technology in Mobil Diesel Efficient™ fuel is engineered to clean up existing deposits and prevent deposit formation that may adversely impact engine performance. By restoring the injector function, your engine is able to operate more efficiently, burn less fuel, protect the critical fuel system components, and reduce unplanned maintenance.

Mobil Diesel Efficient™ fuel helps improve fuel system performance in both on- and off-highway applications. The advanced fuel has been engineered to improve diesel fuel economy and boost engine performance and has been tested in multiple real-world applications.

Ready to get started? McPherson Oil is one of only 7 distributors in the nation currently carrying this new fuel from ExxonMobil.  Contact us today to learn more about the benefits and how you can save on money and downtime.