Exhaust system cleaning: The remedy for crystallization problems in the SCR system

Exhaust system cleaning: The remedy for crystallization problems in the SCR system

The standard for vehicle emissions

Since 2014, the new regulation to limit the NOx emissions to a maximum of 0.08 g/km has been introduced. Vehicle manufacturers were therefore forced to develop new exhaust gas cleaning systems and to install them in modern vehicles. The most famous system is the SCR (Selective Catalytic Reduction) system. In this system, a urea fluid – AdBlue® – is injected in this system to reduce nitrogen oxide emissions, which consists of 32.5 % of urea and 67.5 % of demineralized water. The system consists, among other things, a tank, control unit, catalyst, pump, injector, NOx sensor and exhaust gas temperature sensor. The exhaust gas- AdBlue® mixture is heated in the catalyst, which releases ammonia. Ammonia reacts with the nitrogen oxides and converts them into harmless nitrogen and water vapor.

Why can the SCR system cause problems?

Since AdBlue® tends to freeze at low outside temperatures due to its composition, the manufacturers use heaters that protect the system from freezing cold. These heaters start as soon as the engine is started. Even low motor loads, frequent stopping or longer downtimes mean that the exhaust gas temperature is not sufficient for a complete reaction of the urea fluid. AdBlue® changes again to the liquid state of aggregate, but crystals from cyanismic acid are formed, which gradually clogen, tank, lines and dosing valves. This crystallization can lead to damage and malfunction of the level sensor in the tank. This is noticeable by fueling AdBlue®, but the sensor does not register the filling and spends the message “Tank empty”. In this case, the system and vehicle are no longer functional. Clogging of the SCR catalyst can also lead to considerable damage to the entire system or to error messages (e. g. P20E8). The control lamp lights up red and the engine moves into neutral. Expensive repairs are inevitable.

The solution for crystallization in the SCR system

To prevent crystallization, we have developed a special product that optimizes the freezing point of the urea fluid.

This eliminates clogging of the system. Our “SCR System Clean and Protect (SCRSC) – P6400” not only prevents crystal formation, but also reliably cleans and protects contaminated urea injectors and SCR catalysts. Power loss or engine malfunctions can thus be prevented.

Properties of SCRSC

• Can be used in all engines with SCR exhaust gas aftertreatment starting from the Euro 4 exhaust gas standard.
• Use in short -haul operation for e.g. city buses, taxis, construction machines, tipping trots, tractors and agricultural machines etc.
• Optimizes the freezing point of the urea fluid (AdBlue®) even at high freezing levels.
• Preventive solution that protects SCR systems from pollution and crystal formation and thus ensures optimal operation of the SCR unit.
• Mixed with urea fluid (AdBlue®)

Areas of application:

For use in urea dosing systems and SCR catalysts