Contrary to what you may have seen or heard, a real “Atkinson Cycle” engine is not used in any motor vehicle sold today. LIVC stands for ‘Late Intake Valve Closing.’ It is the valve train and induction system that mimics, to some degree, what the Atkinson system was doing. LIVC is used in many, but not all, hybrid and plug-in hybrid models. LIVC is also used in conventional cars and trucks as well. We will use “LIVC” and not “Atkinson Cycle” when referring to these gasoline engines.
When Toyota was creating the Prius in the early 1990s, they had one big advantage that allows them to develop a new concept based on the old “Atkinson Cycle” engine. They designed a powerful electric motor inside the transmission that allowed the use of a low torque ICE with a high torque electric motor both powering the wheels. This was the first modern hybrid built for mass production.
Bigger Gasoline Engine gets better Fuel Economy
When the Prius was redesigned for the M/Y 2010 (known as “Gen III” is the USA), the internal combustion engine was completely new. It has grown from 1.5 liters to 1.8 liters, but used less fuel on the highway. How is this possible, one might ask? When Toyota increased the displacement, the torque curve had more low-end power. Using their eCVT, the road speed was matched with a lower rpm but the same amount of torque. Less fuel is needed at lower rpms so a larger engine improved the highway mileage.