SCR stands for Selective Catalytic Reduction and DPF stands for Diesel Particulate Filter. The aim of the combination of SCR and DPF is to reduce two types of harmful emissions produced by diesel engines: particulate matter (PM) and oxides of nitrogen (NOx). The DPF part of the system is responsible for capturing and removing particulate matter from the engine’s exhaust system. The DPF is a device that is located in the exhaust system and works by capturing particulate matter as it flows through it. Over time, the DPF can become clogged with particulates, which can reduce engine performance and increase emissions. To prevent this, the DPF periodically undergoes an active or passive regeneration process. Part of the SCR system is responsible for reducing NOx emissions. It works by injecting a urea-based solution (also known as DEF or AdBlue) into the exhaust gas stream. This solution reacts with the NOx in the exhaust gas, converting it into harmless nitrogen and water vapour. The combined SCR and DPF systems work together to ensure that diesel engines meet the increasingly stringent emission regulations i.e. Stage V.
