Due to the EU’s Global Data Protection Regulation, our website is currently unavailable to visitors from most European countries. We apologize for this inconvenience and encourage you to visit www.motortrend.com for the latest on new cars, car reviews and news, concept cars and auto show coverage, awards and much more.MOTORTREND.COM
Cetane Numbers: How diesel fuel’s biggest unknown affects your truck Photo Gallery
SPECIAL REPORT: What Is Cetane?
Bruce W. Smith –
Apr 11, 2017
Photo 1/8 | Cetane Fueling Diesel Close Hand Lead
Photo 2/8 | Cetane Winter Fueling Cold Starts Lw
Photo 3/8 | 002 Cetane Two Diesels Towing Performance | Today’s diesel-powered pickups are primarily used for towing, which places a lot of stress on the engines and fuel systems. Engines made by U.S. manufacturers are designed to run on the lowest cetane number mandated by the EPA, which is 40 CN.
Photo 4/8 | 003 Cetane Tanker Shell Station Commingling | Diesel’s cetane number can change from the time it leaves the refinery to the time it reaches your truck’s fuel tank due to the mixing of fuels during transport and storage.
Photo 5/8 | 004 Cetane Diesel Gas Pump Selectors | Gasoline has octane ratings that are clearly displayed at the pump. In contrast, diesel has no such indicators for its cetane number (CN). Diesel’s CN can vary from 40-59 depending on how and where it is produced and the city, state, or federal EPA requirements for that region.
Photo 6/8 | 007 Cetane Attendant Fueling Diesel | Don’t sweat the CN of the diesel going into your truck’s tank. It’s more important to think of the other aspects of the fuel’s quality and use an additive that addresses those factors (lubricity, detergents, anti-gel, and such) to keep both the engine and fuel system operating at peak efficiency.
Photo 7/8 | 006 Cetane Sidebar Additive Use | It’s smart to use a diesel-fuel additive on a regular basis. When adding a product that includes a cetane improver, follow the instructions closely for the amount needed per gallon. Using more is just a waste of money, and overdosing can lead to reducing the fuel’s density. Raising the CN doesn’t improve horsepower, torque, or mpg, according to engine manufacturers.
Photo 8/8 | 005 Cetane Diesel Kleen Angle Studio | Many diesel-fuel additives include “cetane improvers,” which is typically 2-Ethylhexyl nitrate (EHN). Increasing the CN improves cold starts and reduces emissions, but it has no other meaningful benefit to performance, according to diesel-engine manufacturers and petroleum refiners.