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Publication Date: 2015-Dec-11
Document File: 4 page(s) / 77K

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Optimised Fuel Transfer Control System


Typically on long flights the weight of the fuel on board is significant to the total aircraft weight. Generally, on larger aircraft fuel is stored in multiple locations. Due to the differential locations of the fuel, overall centre of gravity of the aircraft is also affected. Thus fuel has a major impact on the movement of aircraft centre of gravity location, during the course of the flight as fuel is consumed. From aircraft performance point of view it is desirable to have the aircraft centre of gravity as aft as possible within the allowed envelope. The more aft the centre of gravity, the lesser the drag and fuel consumption on the aircraft. Close management is required to ensure  the transition of fuel between the tanks guarantees that the centre of gravity is held at the targeted location for the particular flight. Typically, larger aircraft would generally be equipped with multiple fuel tanks of varying size and installation location. The problem is to find an optimal fuel transfer scheme to maintain the centre of gravity and also to minimise power consumed for the transfers, and time taken to achieve the target centre of gravity. The complexity arises due to the multiple number of transfer schemes possible and then to find an optimal scheme among the various possibilities.

The disclosed invention tries to manage the centre of gravity by initiating transfer of fuel between tanks with the optimal scheme by considering the constraints of time to readjust centre of gravity and also total power consumed for transfers.

Summary of Invention:

Typical fuel systems are comprised of fuel tanks, pumps for fuel transfer and their control systems which are commanded by control computers. The disclosed invention is intended to be part of the control computer which will deduce the optimal scheme of fuel transfers and make use of the pump control systems to achieve the transfers. Also multiple tanks are considered for centre of gravity targeting instead of a single trim tank. On larger aircraft the centre of gravity of respective tanks are also at significant distances from each other so centre of gravity readjustment could also be achieved using these tanks.

Figure 1: Optimised Fuel control system architecture

Figure 2: Optimal fuel transfer logics for centre of gravity readjustment

The proposed invention comprises of methods to –

·         Readjust aircraft centre of gravity by initiating fuel transfers from tanks on the wings and if required from the tanks on the horizontal stabiliser.

·         Optimised control system optimised for time taken for centre of gravity readjustment.

·         Optimised control system targeting minimum power consumption for the total transfer of fuel.

The problem is fuel transfer from multiple tanks is formulated as an optimisation problem. Power consumed and times taken for centre of gravity readjustment are the variables to be optimised with the constraint being the centre of gravity t...