2014 regulations introduce even more downgraded engines. New ones will be 1.6 litre V6 turbo (now it is 2.4, V8, but not turbo), revs will be limited to 15k rpm (now 18k).
I have read that the engines will probably rev to around 12.5k in 2014. Although they will be allowed to rev higher, fuel flow rates will be regulated to a maximum of ~ 100KG/hour. Keeping the revs lower will also decrease the friction which will allow for higher output per KG of fuel. Previously they optimized for max output / CC of engine displacement.
The turbo engines will also have a motor/turbine on the turbo, allowing them to charge the battery from the turbo shaft. They will be able to use the battery power to directly drive the wheels, or spin up the turbo more quickly to the 100k rpm max speed of the turbo.
There is also a plan in 2014 regulations that cars can only use electric engine when in pits. However, this can be delayed because teams are reluctant to it. Besides electric only engine is quiet so it could lead to some accidents in pit-lane.
The turbo engines will also have a motor/turbine on the turbo, allowing them to charge the battery from the turbo shaft. They will be able to use the battery power to directly drive the wheels, or spin up the turbo more quickly to the 100k rpm max speed of the turbo.