What is D.E.F.? Basically it is a 32-67% mix of high purity urine and de-ionized water.
How is it used? This solution is sprayed into the exhaust fumes leaving a diesel engine following combustion. It acts on the exhaust gases and particulates chemically to help eliminate smoke and pollution.
The amount of D.E.F. sprayed into the exhaust stream is based on operating temperature of the exhaust gases and speed. This is all electronically controlled.
Interestingly, if the D.E.F. reservoir is allowed to fall below a certain level, the vehicle automatically is slowed down. This can be very inconvenient for the driver who is trying to get to the destination on time.
Large penalties await anyone interfering with the workings of the D.E.F. system.
Bottom Line per Shellbourne Fuels:
"D.E.F. (diesel emission fluid) usage will vary from one manufacturer to another. The industry average for volume of fluid burned is approximately 2% of fuel usage. But, the urea and distilled water (D.E.F.) consumption varies based upon the reading generated by the exhaust systems sensors.
Shellbourne Fuels fuel enhancers have reduced the quantity of exhaust fluid used by approximately 9% due to reduced exhaust temperatures along the entire exhaust route. We have been very consistent with regards to the D.E.F. usage and every savings these days with constant increases in fuel costs and decreased maintenance and operating costs is vital."