The link to the mentioned ICCT report is here:
Naturally aspirated gasoline engines and cylinder deactivation
Published Tue, 2016.06.21
Summary: Profiles and evaluates recent developments in naturally aspirated gasoline engine technologies, and compares them to the projections made by EPA and NHTSA for the 2025 CAFE regulation.
Naturally aspirated gasoline engines and cylinder deactivation | International Council on Clean Transportation