Diesel Exhaust Fluid (DEF), a key component in Auto Scr systems, is a non-toxic solution of 32% automotive-grade urea and 68% purified water. This fluid plays a crucial role in reducing harmful emissions from diesel engines. Understanding DEF, its usage, and proper handling is essential for maintaining your diesel vehicle’s performance and compliance with environmental regulations.
Auto SCR Systems and DEF Availability
DEF is readily available across a nationwide distribution network, from bulk suppliers to retail stores, online vendors, and most diesel fuel stations. It’s commonly sold in various container sizes, from bulk containers to smaller jugs and bottles, ensuring convenient access for all types of diesel vehicle owners. The American Petroleum Institute rigorously tests all DEF to guarantee adherence to industry quality standards. In Europe, DEF is often referred to as AdBlue.
Example of DEF fill port location on a pickup truck.
DEF Tank Location and Filling Procedures in Auto SCR
Onboard DEF tanks typically hold between 5 and 22 gallons, easily identifiable by their blue caps and “DEF ONLY” labeling. In pickup trucks and SUVs, the DEF filler port is usually located near the fuel filler nozzle. Heavy-duty trucks often have the DEF tank beside the diesel fuel tank, near the driver’s side door. Off-road equipment, due to design variations, may have different DEF tank and filler locations. The DEF tank opening is designed to accept only a DEF nozzle, preventing accidental contamination with diesel fuel. Diesel nozzles are physically incompatible with DEF tank openings, and the distinct blue cap further differentiates the DEF tank from the diesel tank, which typically has a yellow or green cap.
DEF Consumption and Refill Intervals in Auto SCR
DEF refill frequency varies depending on the vehicle type and usage. Light-duty vehicles often require DEF refills around the same time as oil changes. Heavy-duty vehicles and off-road machinery have variable refill needs depending on operating conditions, hours of use, mileage, load factors, and other variables. A general guideline is that DEF consumption is approximately 3% of diesel fuel consumption. For instance, a vehicle consuming 100 gallons of diesel would require about 3 gallons of DEF.
Importance of DEF in Auto SCR Systems
DEF is crucial for the proper functioning of the auto SCR system. Low DEF levels trigger a series of warnings, escalating from visual and audible alerts to engine derating, speed limitations, and eventually, engine starting lockout. Maintaining sufficient DEF levels is essential to avoid these operational disruptions. Proper storage is also critical, as DEF freezes below 12 degrees Fahrenheit. Most DEF tanks and dispensing systems are equipped with heating mechanisms to prevent freezing.
Future of Auto SCR and DEF
The U.S. Environmental Protection Agency (EPA) is continuously striving for stricter emission standards for commercial vehicles through initiatives like the Clean Trucks Initiative. Ongoing advancements in SCR technology, including dosing strategies, catalyst improvements, and placement, are expected to play a significant role in meeting future emissions regulations. This continued focus on emission reduction underscores the long-term importance of DEF in auto SCR systems.
