Abstract: In order to improve the reliability of the main-fuel control unit，a new design scheme has been proposed. In this scheme the pump switching module and metering switching valve are added，the pump switching module is connected with the metering subsystem with the guide vane actuating subsystem and the metering switching valve is connected with the main fuel electro-hydraulic servo valve with the heat fuel return control electro-hydraulic servo valve. Both pump source and metering control backup functions are realized. The mathematical AMESim model of the main-fuel control unit is used to analyze the dynamic performance of the backup switching ability of the new added modules，especially to focus on the parameters fluctuation such as pressure and flow rates during the backup switching period. Simulation results show that the flow rate fluctuations caused by the metering switching process and the pump switching process resume instantly，which only use 0.3s and 1s， respectively, and the actuation subsystem，which works properly，has little effect on the metering system during the single pump working condition.

Key words: Aero-engine；Main-fuel control unit；Backup functions；AMESim modeling

摘要： 为了提高主燃油控制装置的可靠性，在设计方案中增加了泵转换单元和计量转换活门。泵转换单元连接燃油计量子系统和导叶作动子系统，计量转换活门连接主燃油电液伺服阀与热计量电液伺服阀，实现了泵源备份和计量控制备份功能。通过AMESim建立的主燃油控制装置的数学模型对两个新增备份转换装置及功能进行了性能仿真，重点分析了备份切换过程中压力、流量等参数的波动情况。仿真结果表明:泵备份切换和计量备份切换过程引起的燃油波动都能在较短时间内恢复，分别为0.3s和1s。主燃油控制装置在单泵源状态工作时，导叶作动子系统工作正常，对计量燃油子系统的影响极小。

关键词: 航空发动机；主燃油控制装置；备份功能；AMESim建模