Study of the Impact of Malfunctions of and Interferences in the Exhaust Gas Recirculation System on Selected Vehicle Characteristics

The impact of technical vehicle conditions on dynamical and emission vehicle characteristics has been of relatively little interest. Therefore, this study focuses on the impact of malfunctions of and unwarranted interferences in the exhaust gas recirculation system, known as EGR, on selected vehicle characteristics. Attention has been paid to the EGR blanking off and its permanent opening, carbon deposition in the engine’s intake manifold, and other malfunctions and interferences commonly occurring during the lifespan of vehicles. The parameters observed have included the composition of the exhaust gases, smoke opacity, engine power and torque, and others. The measurements have been performed with vehicles of different ages, different numbers of kilometers driven, and different levels of engine management. Blanking off the EGR has led to a multiple increase in the concentration of nitrogen oxides (NO_x) in the exhaust gases, and this unwarranted interference has not been recognized by the engine control unit, so a vehicle would have been assessed as roadworthy during the regular emission inspection. Clogging of the EGR system has caused a 257% increase in smoke opacity as well as a significant reduction in the engine power and torque, which can result in a reduction in the active safety of a vehicle. Since the EGR cooler has not been tight, the particulate matter (PM) and other harmful substances have been drawn into the vehicle cab. This study clearly demonstrates the importance of a properly functioning EGR system and the performing of regular technical and emission inspections for those vehicle parameters that are required by relevant legislation to lower the negative impact of road transport on the environment.

• The article is focused on the malfunctions o and unwarranted interferences in the EGR system.
• Blanking off the EGR multiplied the NO_x production, and it was not recognized by the engine control unit.
• EGR malfunction can lead to a reduction in the active safety of a vehicle.
• EGR leak leads to a serious health threat for passengers.