A decade ago, Toyota’s efficiency virtuoso, the Prius, was the green vehicle; Americans wore their Priuses out in public as if they were merit badges for civic responsibility. While the Prius recently has lost some of its command over those crowds, the new 2017 Prius Prime stands to earn its way back into the hearts of the nerdy, efficiency-focused motorists who embraced the original more than 15 years ago.
To give credit where due: The extended-range plug-in wizardry of the Chevrolet Volt, the entirely gasoline-free operation of the Nissan Leaf, and the Cult of Tesla have likely forced Toyota to what sounds a bit like a crisis of faith. Although Toyota continues to balk about the worth of a high-volume all-electric model—touting hydrogen as the future—it also understands market realities.
It also seemed odd that, in 2012, the king of hybrids produced its first Prius Plug-In with the weakest, most timid all-electric mode among competing plug-ins. Realistically, it was a model that could be plugged in each night, using power from the grid to supplement the standard model’s Hybrid Synergy Drive powertrain, to return far better fuel-economy numbers. But as its lackluster sales testify, that wasn’t what the so-called “efficiency enthusiasts” wanted. In 2012, just as other carmakers seduced these buyers with all-electric cars and plug-in hybrids boasting ranges of about 20 miles, Toyota finally offered them a Prius that had a charging port. But it was capable of just 6 miles of electric range—and that was only when it was driven as if an egg were under your right foot.
To instill more “EV experience” into the Prius Prime, Toyota started with essentially the same planetary gearset and the same two motor/generators, known as MG1 and MG2, down to the part numbers. But with fresh software controls and the use of a one-way sprag clutch, which is like the freewheel on your bicycle, the Prius Prime’s smaller MG1 can be connected with the crankshaft to propel the car in concert with what’s otherwise a Prius’s sole traction motor, the larger MG2.
That new configuration allows the Prius Prime to, finally, shut down the engine to allow driving the car in a pure EV mode. It’s quiet and quick at low speed, you don’t have to worry about juicing the accelerator pedal too much, and it isn’t in any way sluggish at highway speeds.
