Diesel Exhaust Fluid DEF

DEF (Diesel Exhaust Fluid) is one of the key elements of the SCR (Selective Catalytic Reduction) process. It is a clear, non-toxic, non-flammable and non-hazardous organic compound consisting of 67.5% purified water and 32.5% urea. It requires no special handling.

When injected into hot exhaust as a fine mist and passed over a catalyst, DEF helps convert NOx (nitrogen oxide) into nitrogen gas and water vapor—two clean and harmless components of the air we breathe. DEF is stable, colorless and odorless, and meets accepted international standards for purity and composition.

Product Information:

Complies with ISO-22241-1 Quality Standard specification.
High purity urea solution for treatment of SCR equipped diesel engines.
Meets API Standards and carries API Certification.
Optimal storage temperature 23°F to 86°F.
Avoid direct exposure to sunlight.
Non-flammable / Non-hazardous / Non-toxic / Non-explosive
DEF is a chemical product, not a petroleum product.

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Why Use Diesel Exhaust Fluid (DEF)?

To achieve the nitrogen oxide (NOX) levels required by the EPA 2010 standard, most engine manufacturers are utilizing Selective Catalytic Reduction (SCR) systems that require the addition of DEF. Off-road engines will be impacted by similar emission standards which began in 2014.

How Many Litres of DEF Will I Use On Average?

Consumption rates vary but are usually around 5% of diesel fuel consumed. It can be expected that 5 litres of DEF fluid will be used for every 100 litres of diesel fuel.

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How Do I Know When to Refill the DEF Tank?

The EPA requires manufacturers to put measures in place to ensure that SCR equipped diesel engines do not run without DEF. In response, manufacturers have equipped both on-road and off-road SCR units with multiple step driver notification systems. Before the DEF tank runs empty, the operator is given a series of alerts on their dashboard display.

DEF notification systems vary among manufacturers but all are designed to give the operator ample opportunity to refill the DEF storage tank before any impact to full operability. However, if driver inducements are ignored and DEF levels become too low or the fluid is of poor quality, the engine is derated and ultimately speed is limited to 5mph (8kph).

How Long Can Diesel Exhaust Fluid (DEF) Be Stored?

DEF can be stored at temperatures of between 12°F (-11°C) and 86°F (30°C) for a maximum of 12 months.

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Shelf life deteriorates to 6 months when temperatures are held at a constant 95°F (35°C) or higher.

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How Does the SCR Process Work?

1. The NOX reduction process starts with an engine burning clean Ultra Low Sulfur Diesel and producing exhaust that is already much cleaner due to leaner and more complete combustion.

2. Under the control of the vehicle's onboard computer, precisely metered spray patterns of DEF are injected into the exhaust stream ahead of the SCR converter allowing the exhaust gases and atomized mist of DEF to enter the converter simultaneously. Together with the catalyst inside the converter, the mixture undergoes a chemical reaction that converts the nitrogen oxides to elemental nitrogen (N2) and water (H2O).

3. Exhaust gases are monitored via a sensor as they leave the SCR catalyst. Feedback is supplied to the main computer that adjusts the DEF flow to keep NOX levels within acceptable parameters.

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