Abstract: In order to study the modeling method of the digital control FMU(fuel metering unit) driven by stepping motor and characteristics of all components of it，the AMESim/Matlab software platform was used to build a co-model. The hydraulic assembly model and the stepping motor model of this unit were established in AMESim and Matlab/Simulink，respectively. An interface was designed for data-sharing between these two models. Entering the parameters of a certain type of FMU，characteristics of all components and the metered flow rate at the working points can be obtained through simulation calculation，and the results are compared with the experimental data of the unit. Results show that an error no more than 6 percent metered fuel flow rate exits between the co-model and the experiments and indicate that the co-model has higher steady precision and can describe the actual dynamic properties of the unit. Using this co-model，the fuel flow rate can be controlled well and the characteristics of the FMU can be obtained accurately，and it can be used for optimization of component structure and the controlling function of the FMU in the stage of engine control system design.

Key words: Fuel metering unit；Stepping motor；AMESim/Matlab；Co-modeling；Fuel flow rate

摘要： 为了研究步进电机驱动的数控燃油计量装置建模方法和其各部件特性，采用AMESim/Matlab联合建模的方法，对液压组件和步进电机分别用AMESim和Matlab/Simulink建立了各自的模型，完成了联合仿真接口设计，实现了模型间的数据共享。在输入计量装置的参数后，通过仿真计算获得了各工作点燃油流量，并与该装置的试验数据对比研究。结果表明，在工作范围内联合模型仿真的燃油流量与试验值误差在6%以内，联合模型稳态精度高并可反映装置的实际动态性能。采用该模型可以较好地控制燃油流量和获得较为准确的燃油计量装置工作特性，能够在发动机控制系统设计阶段，用于对燃油计量装置部件结构以及其控制性能的优化设计。

关键词: 燃油计量装置；步进电机；AMESim/Matlab；联合建模；燃油流量