The diesel fuel injection system is equipped with an exhaust gas recirculation system (EGR system), to reduce the concentration of toxic nitrogen oxides (NOx) in exhaust gases. At the same time, part of the exhaust gases is returned to the combustion chambers of the engine in order to reduce the combustion temperature and reduce the concentration of toxic substances in the exhaust gases.
The system is controlled by the DDE control unit, which links the injected fuel quantity and the signals from the accelerator pedal position sensor, speed sensor, atmospheric pressure sensor and coolant temperature sensor to each other. The control unit accordingly regulates the vacuum pulse to the EGR valve via the vacuum control valve and ensures the correct dosage of the amount of recirculated exhaust gases. The EGR valve is located in the intake manifold. At low coolant temperatures and high engine loads, exhaust gas recirculation does not occur. The exhaust gas recirculation system is maintenance free.