Auxiliary Power Unit Starting Acceleration Fuel Flow Control Method

Abstract

The invention provides an auxiliary power unit (APU) starting acceleration fuel oil flow control method, which is used for fuel oil flow control in an APU starting acceleration process. The method aims to solve the problems that the existing control method difficultly coordinates a conflict between starting speedability and overtemperature protection, has more control law parameters and is poor in environmental suitability. The method calculates an acceleration fuel oil flow expected value by unique step by step ratio control and two exhausting temperature limiting lines are arranged. When exhausting temperature exceeds an inhibit line (red line), a fuel oil flow is forcibly set to be 0, and protective parking is triggered; if the exhausting temperature only exceeds an alarm line (yellow line), negative correction is performed on the fuel oil flow expected value calculated by an acceleration curve according to an exceeded margin so as to reduce the fuel oil flow (parking is unnecessary). The method is high in environmental suitability, considers both starting speedability and safety and can obviously improve usability and dispatch rate of the APU.

Description

technical field [0001] The invention belongs to the field of aviation power control, and relates to an auxiliary power unit (APU) control method, which is suitable for the fuel flow control during the start-up stage of the APU from successful ignition to when the speed reaches the start-steady-state speed switching point. Background technique [0002] Auxiliary Power Unit (APU) is a small gas turbine engine, which is mainly used to provide bleed air for the starting of the main engine of the aircraft and the environmental control system, and can provide shaft power for the aircraft power generation system through the accessory gearbox. When the aircraft is on the ground, the APU can replace the bulky air source vehicle and power supply vehicle; during the take-off process, the power of the main engine can be used to accelerate the climb to improve the take-off performance of the aircraft; after the aircraft lands, the main engine can be shut down in time , to save fuel and r...

AI Technical Summary

Problems solved by technology

[0006] In order to overcome the disadvantages that the traditional APU start-up acceleration fuel flow control method can not take into account the two objectives of "acceleration plan" and "exhaust temperature limit", as well as many control law parameters and poor environmental adaptability, the present invention proposes a new APU Start acceleration fuel flow control method, in order to obtain the best start acceleration performance under the premise of ensuring the safety and service life of APU, and at the same time improve the environmental adaptability of the system

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