Diesel Exhaust Fluid (DEF) is an essential component of modern diesel engines, which helps to reduce the amount of harmful emissions released into the atmosphere. However, if DEF is not managed properly, it can lead to component failures, especially in winter conditions. One of the crucial aspects of DEF management is allowing the system to purge before shutting off the power. In this article, we will explore why it is essential to allow the DEF system to purge and how failing to do so can cause component failures.
DEF is a mixture of 32.5% high-purity urea and 67.5% deionized water. When DEF is injected into the exhaust stream, it reacts with a catalyst to break down harmful nitrogen oxide (NOx) emissions into nitrogen and water. The DEF system is designed to provide precise dosing of DEF into the exhaust stream, which is crucial for proper engine operation and emissions reduction. The DEF system is comprised of several components, including the DEF tank, pump, injector, and control module.
In winter conditions, DEF can crystallize and freeze, which can cause the system to malfunction. The DEF tank is equipped with a heater and a temperature sensor that ensure the DEF stays within the proper temperature range. However, if the vehicle is parked in extremely cold temperatures for an extended period, the DEF can freeze, and the system may not be able to thaw it out quickly enough. This can lead to blockages in the lines and injector, which can cause the engine to go into derate mode or shut down entirely.
To prevent this from happening, it is essential to allow the DEF system to purge before shutting off the power. Purging involves running the DEF pump for a few minutes after shutting off the engine to clear out any remaining DEF in the lines and injector. This ensures that any remaining DEF does not have a chance to freeze and cause blockages. Some vehicles are equipped with a DEF system purge function that automatically runs the pump for a set amount of time after the engine is turned off. However, if your vehicle does not have this feature, it is essential to manually run the pump before shutting off the engine.
In conclusion, allowing the DEF system to purge before shutting off the power is a crucial step in proper DEF management. Failing to do so can cause component failures, especially in winter conditions, where DEF can freeze and crystallize. By purging the system, any remaining DEF is cleared out, preventing it from freezing and causing blockages. So, make sure to follow this simple step to keep your DEF system functioning correctly and your engine running smoothly.