The direct injection idea relates to making the engine more efficient,
in a normal petrol engine a massive amount of heat is transfered onto the cylinder walls, By injecting into a pocketed piston, similar to the diesels, the conbustion is much more efficient and it massivly cuts the losses

they also run very very lean, around 30:1 in some cases, the VWs have been doing this for quite a while, its pretty amazing stuff really.