How Does AdBlue Work?

AdBlue is a high purity aqueous urea solution used in SCR (selective catalytic reduction) diesel systems to reduce nitrogen oxide emissions. AdBlue is stored separately from the vehicle's diesel supply and works through a sensor located in the vehicle's exhaust system. The sensor measures the amount of solution injected into the vehicle's SCR system to ensure the emissions are safely converted into nitrogen and water.

The injection rate depends on the vehicle’s after-treatment system but is commonly 2 to 6 percent of diesel consumption volume. An electronic control unit measures and adjusts the addition of fluid relative to the engine’s operating speed and temperature.

SCR systems are common in thermal and fossil fuel power stations, gas turbines, large marine power vehicles and locomotive diesel engines. Combustion is optimized in these applications by achieving improved performance with a direct reduction of harmful emissions. Post-treatment stems from the basic principle that the chemical between nitrogen oxides and ammonia produce two relatively harmless substances: nitrogen and water vapor.

AdBlue contains 32.5 percent aqueous urea solution. AUS32 is nonflammable, nonexplosive and nontoxic. AdBlue is neither a fuel nor a fuel additive. It is a light colorless solution that reduces harmful emissions from diesel vehicles. AdBlue was developed to reduce the amount of harmful gases emitted from industrial or heavy goods vehicles.