Because of EXlink’s linkage structure, increased engine friction might seem to be an issue. EXlink, however, features technologies that help reduce engine friction and prevent fuel efficiency losses.
In a conventional engine, when the combusting air-fuel mixture puts the piston under pressure during the expansion stroke, side forces act on the cylinder wall, generating a large amount of friction. Since the amount of side force is in large degree determined by the
connecting rod angle, EXlink has been designed so that the connecting
rod is nearly parallel to the cylinder walls during the expansion
stroke. As a result, the friction loss due to piston side forces is less
than half that of a conventional engine.
Even with its extra linkage expansion parts, EXlink has the same amount of engine friction as a conventional engine, thereby reaping the full fuel efficiency benefit of the Atkinson cycle.