Toyota Engine Development
 

Toyota has developed more efficent engines technical designs
Toyota Develops Engines with Improved Thermal, Fuel Efficiency | TOYOTA Global Newsroom
The new engines to come will be 1.3 liter and 1.0 liter 4 cylinders
I know the current Gen 3 Prius has a 1.8 liter atkinson engine and the newer design for hybirds may be (not for sure) the 1.3 liter. There will 14 different finish product line.

Wonder if the 1.3L engine will end up in the 2015 Prius?