What Is AdBlue and How Does It Work?

AdBlue is a specially formulated solution used to reduce harmful nitrogen oxide (NOx) emissions in diesel exhaust. It is neither a fuel nor a fuel additive and is stored in a completely separate tank in the vehicle.

What Does It Contain?

AdBlue consists of 32.5% high-purity urea and 67.5% deionized (purified) water by weight. This precise ratio lowers the freezing point to -11°C, optimizing the solution for winter use.

How Does It Work (SCR System)?

When a diesel engine is running, AdBlue is automatically injected into the exhaust line just before the SCR catalyst. The heat of the exhaust converts the urea in AdBlue into ammonia.

Inside the SCR catalyst, this ammonia reacts with nitrogen oxides (NOx). The reaction converts harmful NOx into harmless nitrogen (N2) and water vapor (H2O), which are then released through the exhaust.