Diesel Fuel Glossary
Every diesel fuel term a fleet manager needs to know — from CFPP to combustion catalysts. Plain-language definitions with fleet-specific context.
CFPP (Cold Filter Plugging Point)
CFPP is the lowest temperature at which diesel fuel can pass through a standard filter without clogg...
Diesel Fuel Gelling
Diesel fuel gelling occurs when paraffin wax crystals in diesel fuel solidify at low temperatures, t...
Cloud Point
The cloud point is the temperature at which wax crystals first become visible in diesel fuel, giving...
Pour Point
The pour point is the lowest temperature at which diesel fuel will flow under gravity. Below the pou...
Anti-Gel Additive
An anti-gel additive is a fuel treatment that prevents diesel fuel from gelling (solidifying) in col...
Winter Diesel / Winterized Diesel
Winter diesel (also called winterized diesel or #1 diesel) is diesel fuel blended or treated for col...
Cetane Number
The cetane number measures diesel fuel's ignition quality — how quickly it ignites after injection. ...
ULSD (Ultra-Low Sulfur Diesel)
Ultra-Low Sulfur Diesel is diesel fuel with a maximum sulfur content of 15 parts per million (ppm), ...
Demulsifier
A demulsifier is a chemical that separates water from fuel by breaking the emulsion that holds water...
Biodiesel Blend (B5-B20)
Biodiesel blends mix petroleum diesel with biodiesel made from vegetable oils, animal fats, or recyc...
Lubricity Additive
A lubricity additive is a fuel treatment that restores the natural lubricating properties removed du...
DPF Regeneration
DPF (Diesel Particulate Filter) regeneration is the process of burning off accumulated soot from the...
NOx Emissions
NOx (nitrogen oxides) are harmful pollutants produced during diesel combustion when nitrogen and oxy...
DEF (Diesel Exhaust Fluid)
DEF is a urea-water solution (32.5% urea, 67.5% deionized water) injected into the exhaust stream of...
EGR (Exhaust Gas Recirculation)
EGR systems reduce NOx emissions by recirculating a portion of exhaust gas back into the intake mani...
Fuel Polishing
Fuel polishing is the process of filtering and cleaning stored diesel fuel to remove water, sediment...
Microbial Contamination in Diesel
Microbial contamination — commonly called 'diesel bug' — occurs when bacteria, fungi, and algae grow...
Fuel Stability
Fuel stability refers to diesel fuel's ability to resist chemical degradation over time. Unstable fu...
CP4 Injection Pump
The Bosch CP4 is a high-pressure common rail injection pump used in many modern diesel engines (GM D...
Injector Coking
Injector coking is the buildup of carbon deposits on diesel fuel injector tips, which disrupts the f...
Common Rail Injection
Common rail injection is the dominant fuel injection system in modern diesel engines. It uses a sing...
Fuel Dilution
Fuel dilution occurs when unburned diesel fuel enters the engine oil, reducing oil viscosity and lub...