新型柴油车氮氧传感器控制系统

Control System of NOx Sensor for New Diesel Vehicles

氮氧传感器在重型柴油车后处理系统中发挥着重要作用,为了提升氮氧传感器在不同气氛下检测氮氧含量的精度,减少测量误差,提出了一种改进电压定值反馈的氮氧传感器控制策略,该策略可以根据尾气中氧气浓度大小设置电压定值反馈控制中第一腔室的参考电压,以增加氮氧陶瓷芯主泵的泵氧灵活性。通过设置辅助泵的泵电流参考值,实时调整主泵两极所加电压,使辅助泵电流实际值稳定在参考值左右,可提升辅助泵泵氧效率,减少氧气泄露带来的测量误差。通过实验验证,该控制策略可以实现不同氧浓度下氮氧传感器检测氮氧浓度准确性、稳定性、可靠性。

Nitrogen and oxygen sensors play an important role in the after-treatment system of heavy-duty diesel vehicles.In order to improve the accuracy of nitrogen and oxygen content detected by nitrogen and oxygen sensors in different atmospheres and reduce measurement errors,a nitrogen and oxygen sensor control strategy with improved voltage constant value feedback is proposed.This strategy can set the reference voltage of the first chamber in the voltage constant value feedback control according to the oxygen concentration in the exhaust gas,to increase the oxygen pumping flexibility of nitrogen oxygen ceramic core main pump.By setting the reference value of the pump current of the auxiliary pump and adjusting the voltage applied at the two poles of the main pump in real time,the actual value of the auxiliary pump current can be stabilized around the reference value,which can improve the oxygen efficiency of the auxiliary pump and reduce the measurement error caused by oxygen leakage.Experiments show that the control strategy can realize the accuracy,stability and reliability of nitrogen and oxygen concentration detection by nitrogen and oxygen sensor under different oxygen concentration.