Adaptive control of exhaust gas recirculation at nonroad vehicle diesel engine

At diesel engines with fuel direct injection, the problems with toxic exhaust compounds concern mainly nitrogen oxides (NOx) and Particulate Matter (PM). For reduction of the NOx's, the exhaust gases are feedback to the combustion chamber. This results with a lower combustion temperature and decrease the emission of NOx gasses. The mass of the recirculated gases cannot be too high because it might lead to an increase in the PM emission. In nonroad vehicle engine the component responsible for the exhaust gases recirculation is most a two state (open/close) EGR Valve. Another problem in this type of combustion engines is volatility of its ecological parameters during exploitation. The reasons are various operation conditions of the engine, fuel quality ect. So, according to the proposed solutions, the engine controller must track these variations. The mass of recirculated gasses must also be corrected. In the proposed solution the EGR valve is a prototype construction of an electronically controlled EGR. The openness of the valve is freely programmable and is controlled by adaptive algorithm saved in the ECU (Electronic Control Unit). As feedback signal to control the openness of EGR valve is used an NOx sensor placed at engine outlet pipe. The paper describe an control circuit of EGR Valve and include research results of nonroad vehicle diesel emissions (NOx and PM missions). The proposed adaptive control of EGR Valve shows potential to reduce especially NOx emissions in aspect to fulfill further emission regulation TIER/Euro