Hmmm, this is really odd.
Normally Airbus is not stupid at all.
But the reasoning behind this patent given in the description is really strange. They want to reduce thrust and size of the under wing engines. And hope to compensate most of the additional weight of the third engine by this reduction in size.
That leaves still somewhat more weight and less efficient smaller engines.
So: Where is the benefit?
Is it an approach to be able to use very high bypass ratio engines with relatively low thrust for a given diameter ? Geared Turbo Fans / Propfans ?