Seminal petrol-electric hybrid hatch applies plug-in technology to its latest generation in a bid to show that original is still best
Ten years ago, a group of engineers at Toyota’s japanese HQ had a daydream – and it has just led to this: the second- generation Prius Plug-in petrol-electric hatchback. “The idea that inspired us,” says chief engineer Shoichi Kaneko, who worked on the first Prius Plug-in before leading his team to produce its replacement, “was to come up with an electric vehicle that charged itself.”
Two decades earlier, a similarly simple idea had become the driving force behind the original Prius hybrid: ‘the EV you could drive like a normal car’. Only a Japanese car maker, surely, could pioneer a powertrain so complex that it would take the rest of the car industry decades to catch up, and then use it to deliver on such a beautifully pure vision as that one.
“It’s a clever car with some very neat features, chief among them the solar roof panel”
Twenty years on from the launch of the hybrid hatch that changed the world, though, Toyota finds its Prius sub-brand under attack. It needs another reinvention; another light bulb moment. So is the Prius Plug-in that spark? Not quite, I fear. It’s a clever car with some very neat features, chief among them a solar roof panel that could put enough power into its drive battery for a 90% charge in little more than a week.
But this new Prius Plug-in quite plainly isn’t the car to restore Toyota’s reputation as the rightful owner and keeper of the petrol- electric playbook. I’m afraid it’s a sideshow; a tangent; a car that fulfils its own limited brief and will work well enough as a bridging platform for a few thousand very particular European customers who aren’t quite ready to take the plunge with a full EV.
But compared with the hybrid state of the art – the latest- generation petrol-electric offerings from the European car makers who’ve spent two decades trailing in Toyota’s wake but are now in a position to go toe to toe with it – it’s weedy and one-dimensional.
So much is already obvious after just a few hours in the car, as well as after very recent and useful acquaintance for this tester with many of its direct competitors.
What the Prius Plug-in is, under the softened, massaged styling that moves it discreetly away from the more visually arresting regular Prius and Mirai, is a fourth- generation Prius whose electrical powertrain has been quite widely overhauled. An 8.8kWh lithium ion battery is housed under the boot floor in place of the standard Prius’s much smaller nickel-metal-hydride one, alongside a more sophisticated high-voltage electrical system to shuffle power in and out of it.
Toyota claims a big gain in real-world performance and drivability for the car by virtue of fitting its first ‘dual-motor’ hybrid powertrain. In fact, the company has simply made the Prius’s existing motor hardware work harder. There’s a new one-way gear between the car’s 1.8-litre Atkinson-cycle petrol engine and the smaller motor/generator of the Prius’s two-motor hybrid drive set-up. This allows both of the Prius Plug-in’s electric motors to work together to drive the car when it’s running in EV mode, upping electric-only oomph from 71bhp to a combined 102bhp.
The increase in performance is also made possible by that new 352V lithium ion drive battery, which gives the Prius Plug-in a top speed of 84mph when running in zero- emissions mode as well as a claimed zero-emissions range of 39 miles. But what that new battery can’t do is create greater peak system power and performance oft he sort that you only get with the main electric drive motor and piston engine running in tandem. And so, in outright terms, the Prius Plug-in is actually no more powerful or faster-accelerating than a standard Prius, while exceeding the price of the latter by some 40%.
You get 121bhp and 0-62mph in 11.1sec for almost the same price that BMW asks for the 249bhp 330e, which is capable of 0-62mph in just 6.1sec, and both cars are rated in the same benefit-in-kind tax band.
But let’s not overstate the importance of power and pace to com mend ably virtuous Prius buyers. To them, the Prius Plug-in may be more than exciting enough – and virtuous enough, no doubt, given that it’s rated at just 22g/km of CO2 and for NEDC combined fuel economy of a frankly absurd-sounding 283mpg. And besides the modified hybrid drive system and the solar panel roof, this is a car with an innovative new gas-injection heat pump air conditioning system and a battery warming system, both of which boost its zero-emissions driving range and efficiency.
If plug-in hybrids, or PHEVs, are to have a future after the correction to the laughable way they’re emissions-tested by the EU, and after the government-funded incentives to buy one finally dry up, it seems to me that they need to become two cars in one: they need the refinement, response, ease of use and zero-emissions capability of an EV around town as well as the longer- legged authoritative pace, range and drivability of a combustion-engined car on longer journeys.
It may have been different before, but with credible 250-mile battery- powered cars emerging onto the market at affordable prices, duality will become absolutely key to the appeal of a good PHEV. Right now, most of them are better at one side of the equation or the other – and the Prius Plug-in is the same, as we’ll get on to in more detail in a moment.
But first,the cabin: it’s almost identical to that of a regular Prius except for the two-seat-only second row. Its boot is smaller than that of its sister car on account of its battery positioning, too. On both fronts, with the likes of the Volkswagen Passat GTE available at a similar price point, we’ve reason to expect better material quality and practicality.
Away from its attention to the hybrid powertrain, Toyota’s efforts have been spent on making the Prius Plug-in a more comfortable and refined car to drive than the regular hybrid. Noise and vibration insulation measures have been added under the bonnet, inside the front wings, under the cabin carpet and around the rear wheel arches, and the suspension springs, damper and anti-roll bars have been retuned for greater compliance.
The gains are just about noticeable, although you wouldn’t call this a refined car to drive in outright terms. It rides with more suppleness than the regular Prius but the chassis can still thump and rumble a bit over poorer surfaces. And although the powertrain is predictably quiet under electrical power, the petrol engine’s tendency to rev away noisily to its redline when you use anything more than about 50% of the accelerator travel remains a nannyish bugbear.
Up to about 50mph, progress feels strong in EVmode. The Prius Plug-in has more than enough power and torque to keep its combustion engine quiet and responds to the pedal in the super-keen, linear proportion you want from an electrified option. The brake pedal feel is the familiar muddled jumble of regenerative force and sudden apparent friction that makes slowing the car smoothly an exercise in guesswork. Yet you can still enjoy the car’s hushed flit around urban roads – while it lasts. Toyota’s 39-mile electric range claim isn’t to be believed. Repeated testing suggests that it’s more like 25 miles, which is good but not exceptional.
Once the lithium ion drive battery is depleted and you’re beyond the bounds of the city, the Prius Plug-in takes on a dynamic character indistinguishable from that of a regular Prius, albeit one with an extra 130kg to lug around.
On A-roads and dual carriageways, it’s slow and somewhat alienating under acceleration. Along twistier stretches, it handles competently but with familiar remoteness, those standard 15in wheels and 65-profile economy tyres running out of grip quite frequently, and quite suddenly, if you try to keep up a head of steam. Drive more conservatively, as Prius converts undoubtedly will, and your reward is hybrid-mode fuel economy in the high-60s – a far sight better than most PHEVs will return, but also only about 5mpg better than you’d get from a regular Prius.
All up, that may be enough to convince a minority of buyers that Toyota offers the best plug-in hybrid, but it’ll do little to endear the breed to a wider audience. It has taken Toyota four model generations and 20 years to bring the regular Prius to a point where you might say it’s finally good enough, in almost every way that matters, to seamlessly replace a conventional £24,000 hatchback for the average driver.
By adding £10,000 to its price and beefing up its electrical reserves but doing little to the rest of the car, Toyota has promoted the Prius way beyond its abilities and stretched its credibility as a product too far. For the next 10 years, we’d suggest less daydreaming and more benchmarking might serve the company better.
Engine: 4-cyls, 1798cc, petrol, plus dual-motor hybrid assist
Power: 121bhp @ 5200rpm
Kerb weight: 1550kg
Top speed: 101mph
Economy: 283mpg (claimed)
CO2/tax band: 22g/km, 9%
Rivals: BMW 330e, Volkswagen GOLF GTE
Effective as an urban EV but not the template on which we hope the plug-in hybrid of the future will be based