Toyota Prius Prime Gets The Plug-in Hybrid Right, Now About That Design


2017 Toyota Prius Prime

Ok, let’s immediately deal with the elephant in the room. The Toyota Prius Prime is not an attractive vehicle. In fact, to my eyes, it’s quite homely. Now that we have that out of the way, I’ll leave the aesthetic judgements to your own tastes and move on to how Toyota’s sophomore effort at a plug-in version of its icon works. While the first-generation Prius PHV was a bit of a swing and a miss, the functionality this time is in most respects a home run.

As we all know by now, so far Toyota hasn’t been a huge proponent of plug-in electric vehicles, preferring instead to continue refining its Hybrid Synergy Drive system and commercialize fuel cell technology. However, a decade ago, a sizable chunk of the Prius faithful began adding more battery to their trusty hybrids along with a plug. This green hardware hacking community grew to the point that a number of shops in California were doing a brisk business in these installations and a couple of companies sprang up with turnkey kits.

2017 Toyota Prius Prime

Seeing that there was at least some demand in the market and the state of California was pushing hard for plug-in vehicles. After the third-gen Prius debuted, Toyota basically replicated what the aftermarket had been doing. They swapped the nickel metal hydride battery for a larger capacity 4.4-kWh lithium ion unit, added a plug and charger and basically called it a day.

Unfortunately, while the Prius had an EV mode button, the hybrid system really wasn’t optimized for true EV operation. While the Toyota hybrid system has always had two motor-generators, only one was used for propulsion while the other was used for regenerative braking and as the ground for the continuously variable ratio transmission. This meant that in order to drive electrically, you needed an exceptionally light touch on the accelerator. Anything more would quickly bring the engine in to help.

2017 Toyota Prius Prime

Even on the EPA drive cycles that use exceptionally low acceleration rates, the Prius PHV was still using the engine in blended mode and got a range rating on the EPA fuel economy label of 11 miles. If you could manage to keep it running without firing the engine, you might get about five to six miles.

When it came time create the Prius Prime for 2016, Toyota took the task much more seriously. While Toyota frequently derided the powertrain concept behind the Chevrolet Volt back in 2007 and 2008 when I was writing about it for Autoblog, they seemed to actually take some lessons from it for the Priime. The battery has grown to 8.8-kWh and the drive unit has been changed. Where previous Toyota Hybrids have only used motor-generator 2 (MG2) for propulsion, the prime now has a clutch that couples MG1 and MG2 together.

While the implementation details are probably different, the premise is probably much like the Volt. At higher load conditions or speeds, the coupled motors can provide more power and torque and they can be kept closer to their optimal efficiency range. The result is that you can now drive a Prius Prime as an EV without really trying very hard. According to the EPA certification, the Prime can get up to 25 miles without using a drop of gas and it will happily run on electrons at highway speeds. In my week with the Prime, I averaged almost 27 miles per charge, although the moderate temperatures in the upper 60s and low 70s meant I didn’t need to use air conditioning most of the time. If you are going to do some highway driving which will consume the battery more quickly, you can use a hold mode to preserve the battery charge for later in the trip and use standard hybrid mode at higher speeds.

2017 Toyota Prius Prime

The current generation of Prius including this Prime edition is the first of the breed to actually exhibit what could be described as reasonably engaging driving dynamics. The TNGA platform which now also underpins the latest Camry is a pretty decent setup with struts at the front and a double-wishbone independent layout at the rear replacing the old torsion beam. Even the steering is nicely weighted if not necessarily brimming with feedback.

Going through corners, the Prime feels reasonably well balanced and car is relatively responsive to steering inputs until you approach its limits. Sadly, physics being what they are, those limits aren’t particularly high thanks to the low rolling resistance tires that aid fuel efficiency. Once you do hit the limits, the 195/65R15 tires at the front wheels pretty much give up entirely and the Prius exhibits some pretty horrendous understeer.

2017 Toyota Prius Prime

This is a car for covering ground while using the absolute minimum amount of energy, not setting autocross records. That’s not a criticism, just an observation. There are plenty of cars out there far better suited to autocrossing, that’s the beauty of a competitive marketplace.

The other main complaint I have about the Prius Prime is the same I’ve had about every Prius, the instrumentation and infotainment system. Specifically, that the former exists in a thin strip across the center of the dashboard. It’s not far from my peripheral vision but I still prefer it directly ahead of me, especially when there isn’t a heads up display.

2017 Toyota Prius Prime

The other main distinguishing feature of the Prime from non-plug Priuses is the central display screen. The Prime gets a larger 11-inch, portrait oriented display flanked by some capacitive touch buttons for volume and tuning. I am of the strongly held opinion that until cars can fully drive themselves, predominantly touch controls that you have to look at don’t belong in cars.

Unlike the standard Prius, all of the main climate and audio controls here are in the menus within the touch interface. While the interface is relatively free of lag and not too convoluted, you do still have to divert your eyes from the road. With a lane departure assist system that provides almost no noticeable assist, I’d prefer that Toyota stuck with the base system. At least Toyota upgraded the Prime to a much improved display that is actually visible through polarized sunglasses unlike the truly awful unit in other Priuses.

2017 Toyota Prius Prime

Despite being rather homely overall, the Prime does have some interesting details such as the compound curvature glass in the hatchback. It’s presumably there to help manage the airflow coming off the back of the car. Given the steep angle of the back glass and that curvature, I wouldn’t have been surprised to see the image in the rear view mirror be severely distorted, but somehow Toyota managed to make it completely clear and straight. The hatch that holds the glass is also interesting, being one of the first affordable car applications of carbon fiber. We’re not just talking about some carbon scraps used as trim, but the whole hatch is made from the composite material to help offset the added weight of the battery. Unfortunately, those fancy curves in the glass do preclude the use of a rear wiper so you might have some degraded visibility in the rain or snow.

So the Prius Prime isn’t very attractive overall and doesn’t have a whole lot of performance. It is however spacious with plenty of head room front and back. It’s also remarkably fuel efficient. During my week with Prime, I had several commutes of 50 to 60 miles round trip that used up the battery capacity. However, factored over the total distance, gas mileage averaged out to an impressive 88 mpg. With a base price of $27,100 and $29,685 delivered for the Premium trim I drove, this car is a pretty impressive value. If you’re looking something with enough range to handle most people’s daily commuting needs without the worries of finding a place to charge on a road trip, this is an amazing choice. Just keep your eyes closed as you walk up to it.

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