This might be a dreadful admission to make, but until late December, I'd never driven a Toyota Prius. It's not that we've ignored the hybrid in our coverage, it's just that it's always been someone other than me driving it. To rectify that error, I spent a week with a 2020 Prius Prime Limited, the $33,500* range-topping plug-in version of the car that, for a while, was a synonym for being environmentally conscious.
Not a huge amount has changed in the two years since Ars last drove a Prius Prime. It's still a plug-in hybrid EV with a 1.8L, four-cylinder internal combustion engine under the hood that generates 95hp (71kW) and 105lb-ft (142Nm). The internal combustion engine uses the more efficient Atkinson cycle; this delays closing the intake valve until the piston is already moving back up during the compression stroke, meaning that it compresses less volume than gets expanded subsequently in the power stroke. As a result, the engine has a thermal efficiency of about 40 percent, which is better than just about any other engine outside of Formula 1 or Mazda's Skyactiv-X engine.
The internal combustion engine is joined by a 71hp (53kW) permanent magnet synchronous electric motor, the two working together to drive the front wheels through a continuously variable transmission, for a total system output of 121hp (90kW). (Beware, purists: the internal combustion engine can directly drive the those front wheels when it's more efficient to do so.) The battery pack is an 8.8kWh lithium-ion unit weighing 265lbs (120kg) giving the Prius Prime a range of up to 25 miles (40km) on electric power alone. Recharging is just via AC power and takes about two hours with a 240V source or five hours connected to a 110V socket. The EPA rates it at 133mpge or 54mpg on gasoline alone.
If only you could drive further in electric silence
The point of a PHEV like this is to plug it in each night at home, and were I in a position to do that, I might only have heard and felt the gasoline engine fire up on steep hills or when I engaged "power mode." In practice, since I don't have anywhere to plug in a car, that meant quick electricity top-ups when grocery shopping or the like, and so I rarely started the day with anything approaching a full battery. In rather cold December weather here in the District of Columbia, I actually recorded closer to 45mpg over the course of a week that involved a decent mix of low-speed urban errands and a couple of longer trips with some freeway action.
Which means I agree with our earlier drive of the Prius Prime—it needs a bigger battery. Then again, that's a claim you could make about almost every PHEV out there, barring the (now deceased) Chevrolet Volt, Honda Clarity, and Polestar 1. Driving a Prius Prime with some charge in the battery is a much more pleasant experience than when you run out of electrons. The gasoline engine might be highly efficient, but it also sounds rather thrashy and buzzy, and it makes a stark contrast to the peaceful serenity you enjoy when just the electric motor is making you go.
Driving around in Auto EV mode will default to electric power as much as possible, but you can engage hybrid mode, which relies mainly on the gasoline engine and uses the electric motor as support. The car will also switch to this mode if you deplete the battery. (The battery actually maintains a certain state of charge so that it will always work as a hybrid like the not-plug-in Prius.) On the other hand, in power mode I discovered that a Prius can actually be quite fun to drive. With narrow, low rolling resistance tires, front grip is absolutely finite, but the key to a smile is maintaining momentum. Driven that way, expect to get about 37mpg. But driving a Prius like that seems like it's completely missing the point.
Design-wise, the Prius Prime has changed little since its first appearance back in 2017. So yes, it still looks like two different cars have crashed into each other. I did like the fetching Blue Magnetism paint, although I failed at photography, so most of the photos you see above are Toyota's, which is why that car is Supersonic Red (a $425 option).
The changes are on the inside
The interior of the Prius Prime is where you'll find the tweaks for MY2020. There are lots of shiny black plastic trim, which is very on-trend, but I'm increasingly convinced that's going to get dated, quickly. As in every other car that goes for the piano black look, fingerprints and dust become more apparent. The mix of materials in the cabin is a little maddening. Some of the plastics definitely feel like they were chosen because they were cheap, but then you touch or operate either of the column stalks (for the lights and wipers), they're so good I specifically made a note to mention them. (Honestly, they feel like they belong in a car twice or three times the price.)
The infotainment system has a large, 11.6-inch portrait screen (in both Limited and $29,500* XLE trims, but not the $27,600* LE). It's better than some other Toyotas, but the UI still feels so unpolished compared to some of its competitors. Now, it finally offers Sirius XM, Apple CarPlay (but not Android Auto), as well as Amazon Alexa integration. The back seat is where you'll find the other changes for MY2020. It will now seat three, instead of just two, and there are a pair of 2.1A USB (type A) sockets to keep two-thirds of your rear occupants charged on the move.
Happily, Toyota isn't gating most of the advanced driver assists and safety features in the more expensive trim levels. All Prius Primes are fitted with Toyota Safety Sense, which bundles together forward collision warning and automatic emergency braking with pedestrian detection, lane-departure warnings and lane keeping, adaptive cruise control, and automatic high-beam headlights. However, you will need to spring for the Limited if you want blind-spot monitors with rear cross-traffic alerts, a heads-up display, or ultrasonic parking sensors.
*All trims of the Prius Prime qualify for a $4,502 IRS tax credit based on battery size.