Electronically controlled delivery of diesel exhaust fluid into the exhaust train
The main function of the supply module is to deliver the DEF form the tank to the dosing module via a precise solenoid membrane pump. There are two variants in the portfolio: The value line without pressure sensor and high line variant with pressure sensor. This pump operated only on demand, when DEF should be injected into the exhaust aftertreatment system. The concept has no backflow DEF line into the tank. During Start/Stop operation, the system stays pressurized. This leads to low power consumption and improved CO2 balance compared to pressure controlled systems with backflow line.
To protect the dosing module in cold condition, the pressure line is purged, when engine is turned off by ignition key. The DEF is filtered by a lifetime filter. Due to the flat design of the filter, the residual volume in the tank is below 100 ml – a big benefit for the vehicle manufacturer for tank design and usable tank volume. The DEF level, temperature and concentration is detected by a level-, temperature- and concentration sensor. In cold operation condition below -11 °C, when DEF will freeze, the integrated tank heater will thaw the necessary DEF dosing amount to fulfill OEM requirements.