The Toyota RAV4/Suzuki Accross ICE unit uses the Atkinson Cycle (it has been designed to use even a lower grade of fuel than E10) rather than the more common Otto cycle, it design to simulate the original Atkinson engine, the Atkinson cycle opens the inlet valves much later than Otto cycle despite being a 2500cc it only draws 1600cc/1700cc on the inlet cycle, the exhaust cycle is a conventional Otto cycle thus giving a cleaner burn for the next cycle.
As a comparison our previous Mitsubishi Outlander PHEV 2400cc ice unit use a variable valve timing using both the Atkinson and Otto cycle, using E10 as opposed E5 on that vehicle made a 2 mpg difference.
Excuse my grammar I have a brain injury.
Unfortunately I have suffered a brain injury and occasionally I get confused and often say the wrong thing.