By Sam Moses [NewCarTestDrive]
For 2010, the new four-cylinder engine goes from 1.5 to 1.8 liters,
and horsepower increases from 76 to 98. Combined with the electric
motors, there's a total of 134. The larger engine provides more torque,
allowing the Prius to maintain freeway speeds at lower rpm, boosting
fuel mileage. It's an Atkinson Cycle engine (different valve timing and
breathing). CO2 emissions have been reduced from a score that already
tops the charts.