2017 Toyota Prius Prime Plug-In Hybrid

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.

Faster to 40 mph Without the Four-Banger

Toyota has teased us with a few more facts and numbers to bolster that impression: It says the Prime accelerates more quickly to 40 mph in its EV mode than it does in normal hybrid mode with the engine running. And it will accelerate to 60 mph, in either its EV or hybrid modes, in about the same time as the standard Prius—a claimed 10.6 seconds. In our tests, we’ve seen a Prius Four Touring get to 60 mph in 10.4 seconds, while a Prius Two Eco did it in 9.6. So call it a 10-second car.

Total system output is the same 121 horsepower as other Prius models, Toyota says. Due to gearing and the way its power and torque curves map out, the Prius Prime’s EV mode is the quicker one at low speed, while Hybrid mode becomes stronger and quicker above about 60 mph. Top speed in EV mode is 84 mph, which makes it more usable than the former Prius Plug-In’s (mostly theoretical) 62-mph top end in EV mode.

Customer deliveries of the Prius Prime aren’t due to start until November at the earliest, but Toyota allowed us an early, limited drive of development prototypes on a closed circuit in Japan (one Toyota prefers we don’t name). During that drive, we briefly eased up toward an indicated 84 mph on the speedometer without hitting a hard limiter. Toyota says the car can keep cruising at that speed using only its electric motors until it nears the bottom of the battery capacity set aside for EV mode. Toyota employs an 8.8-kWh lithium-ion battery in the Prime, more than 12 times the nominal capacity of the Prius Eco’s 0.7-kWh lithium-ion battery.

About those modes: The Prime will default to EV mode when it starts if the battery’s state of charge (SOC) is sufficient to allow electric driving. Hybrid mode is what it defaults to after the SOC drops below a certain threshold, or it can be selected at startup to reserve the electric power for later use, employing a (small) portion of battery capacity for hybrid driving. And then there’s the EV Auto mode. Engage it after startup and this mode judiciously juggles power sources to maximize efficiency, so long as there is enough juice in the battery to allow electric driving.

Toyota wouldn’t let us try driving the car in this EV Auto setting yet; officials say that it’s similar to the main operating mode of the previous Plug-In model, although where that car might fire its gas engine at one-third of the accelerator pedal’s travel, the Prime will allow the use of two-thirds before starting the four-cylinder. Within each mode, the driver can choose Normal, Eco, and Power settings that change the accelerator response noticeably without altering maximum output or any of the hybrid system’s operating parameters.

With the added battery cells and related hardware, Toyota claims that the Prius Prime weighs just 77 pounds more than a standard Prius, identically equipped. Much of the credit goes toward a special carbon-fiber hatch (manufactured by Toyota, not an outside supplier) and two-place back seats rather than the usual three-person bench.

Embracing the Freak Scene

There’s a concerted effort here to make the Prime look different from the rest of the (already different-looking) Prius lineup. In addition to front and rear styling details that seem far better coordinated than those on the non-plug-in models (the thin, low headlamps might be an exception), there’s one detail that some will find groovy and others will see as strange: The wavy rear window, as opposed to slightly convex conventional glass, has a concave center section, which does not affect aerodynamic drag, as it turns out. All we can say is that it doesn’t distort the view out the back all that much.

Inside, Toyota installs a huge, 11.6-inch vertically oriented touchscreen, loaded with additional efficiency apps and tools (such as a charging-station finder and remote management of charging functions). The driver does have to look down from the road a bit to see some of the screen features, although there’s an available head-up display.

We didn’t get a chance to play with those elements, but we did get a feel for ride and handling. In a back-to-back drive with a standard Prius, the Prime showed better body control through a series of test-track esses and, from what we could tell, a more refined ride. The project’s chief engineer, Koji Toyoshima, confirmed that the Prime has entirely different suspension tuning—and most noticeably, more rebound damping, helping it feel more secure over heaves.

After it has exhausted its battery charge, the Prime will return the same 52 mpg combined EPA rating as the standard version, Toyota says. That’s a claimed 10 mpg better than the charge-exhausted Volt.

Emerging from this first contact with the Prius Prime, we’re convinced that this model will be the best-driving Prius yet—especially for those who consider strong and silent to be a better soundtrack than the groan-and-thrum of a gasoline engine.

Staying on the grid

We remain less convinced about Toyota’s decision to offer just 22 miles of electric driving range. Yes, the automaker doubled energy-storage capacity from Plug-In to Prime—from 4.4 to 8.8 kWh—but realistically it’s still inadequate for Americans unless they have a charging station to plug into midday, perhaps at work. That’s not something most of us can rely on, so far. The Volt’s 53-mile all-electric range, on the other hand, easily accommodates the vast majority of round-trip daily commutes while saving the charging sessions for overnight. Chrysler is targeting 30 all-electric miles for its plug-in Pacifica hybrid, and even the Hyundai Sonata PHEV will go about 24 miles on electron power. Hyundai says it has targeted “over 25 miles” of electric range for the plug-in variant of its 2017 Ioniq range.

Toyoshima has hinted that the Prime was conceived to accept batteries with higher energy density when they become available (or cost effective). If Toyota could increase its range to 45 or 50 miles, the Prime would better fit the current market reality, which is that buyers place real dollar value on all-electric range. The Prius Prime will need to hit a narrow price window, above the standard 2016 Prius’s starting price of $25,035 but below the 2017 Volt’s $34,095 MSRP. Narrowing Toyota’s calculation is that the Prime’s battery capacity qualifies it for a $4500 federal tax credit, while the Volt’s 18.4-kWh battery qualifies for the full $7500 credit.

For now, we can say that the dorkiest Prius is shaping up to be the best one. And that, at Toyota as elsewhere, the nerds are definitely exacting their revenge.