The Prius has been the mpg leader—a title it has earned yet again with its 2010 model. A low (0.25) coefficient of drag is where the efficiency starts, but the real secret is in the refinements to Toyota’s hybrid system. The 1.5-liter engine has been replaced with a torque-rich 1.8-liter unit that still operates with the late-intake-valveclosing Atkinson cycle. More low-end torque means the engine doesn’t have to work as hard. The hybrid system uses the same planetary continuously variable transmission (CVT) as before, but with a new twist. The main electric motor drive was downsized and produces less torque (153 lb-ft versus 295). But a reduction gearset that connects it to the gearbox allows that motor to spin faster. Consequently, it makes 80 peak hp, 13 more than before.
The nickel-metal-hydride battery pack has a more effective cooling system too, which allows peak output to rise from 25 kilowatts to 27. And now, finally, Prius owners can hit an EV button and cruise for about a mile locked in electric drive. On a recent test, the car delivered a thrifty 52 mpg in the city—even better than the EPA’s 51-mpg rating.
Toyota’s hybrid system remains the benchmark. But the tech extends beyond the drivetrain with optional solar ventilation, radar-based cruise control and intelligent parking. Yet it’s the driving dynamics that make the Toyota appealing to a wider audience. This is the first Prius that’s actually fun to drive.
interesting....keep it up
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