基于backstepping方法的柴油机urea-SCR系统控制设计

为实现urea-SCR系统较高的NOx转化率以及较低的氨逃逸, 提出一种面向控制的urea-SCR(urea SelectiveCatalytic Reduction)模型,设计了一种基于backstepping技术的非线性控制器。将模型参数误差看作外界的干扰输入, 并在输入到状态稳定性框架内分析了该闭环系统的稳定性。同时, 研究了基于一种配有urea-SCR系统的精确enDYNA模型, 并在ECE(Economic Commission for Europe）瞬态测试循环条件下进行了测试。该控制器能调节参数可变的非线性系统, 跟踪理想的氨覆盖率, 适用于轻型车辆配备的urea-SCR系统。与传统的PID(Proportion Integration Differentiation)控制器控制效果对比实验表明, 基于backstepping控制器降低了氨逃逸量且具有更好的鲁棒性。

Design of Urea-SCR Systems Controllerfor Diesel Engines Using Backstepping

For simultaneously achieving high NOx conversion efficiency and low ammonia slip, a new control- oriented model presentation of urea-SCR systems is developed. And a novel nonlinear controller using backstepping is presented, which drives the parameter-dependent but also varying nonlinear system totrack the desired ammonia coverage ratio. Taking into account the lower vehicle weight and costs, the proposed controller was suitable for simple SCR aftertreatment system of light-duty vehicle. Model uncertainties including parameter error, etc. were also considered as additive disturbance inputs, and the closed-loop error system dynamics was analysed in the frame of input-to-state stable. Based on a validated enDYNA diesel engine model with urea-SCR aftertreatment systems, transient ECE（Economic Commission for Europe） driving cycle simulation is conducted to evaluate the effectiveness of the proposed control strategy. And comparisons with conventional PID （ Proportion Integration Differentiation） urea-SCR controller are presented to show the advantages of the proposed control strategy