Exhaust Gas Recirculation (EGR system) (BMW 7 Series E32)

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 the exhaust gases. In this case, part of the exhaust gases are returned to the combustion chambers of the engine 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 amount of fuel injected and the signals from the accelerator pedal position sensor, the speed sensor, the atmospheric pressure sensor and the coolant temperature sensor. The control unit regulates the vacuum pulse to the EGR valve accordingly 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.

(This article is based on information from the website: www.bmwman.ru)