Toyota Prius Plug-in - First Drive

The hybrid pioneers hit back at their competitors with a plug-in version of the Prius

David Wilkins
Tuesday 11 September 2012 11:41

Hear the word hybrid and the chances are that the first car manufacturer you’ll think of is Toyota. The Japanese company was a hybrid pioneer and its Prius became a fashionable hit with Hollywood stars, as well as achieving huge popularity with Londoners as one of the first cars to beat the Congestion Charge, thanks to its low emissions. Toyota later went on to put the Prius drivetrain, or something like it, into the Auris and the Lexus CT200h.

But its competitors weren’t just standing idly by. Honda, also among the first to offer hybrid technology, came up with the Insight, a car broadly comparable with the Prius, and the smaller, sportier CR-Z. The CR-Z was appealing because it offered a hybrid drivetrain incorporating a manual gearbox; that made it more interesting to drive than the Prius, which uses a continuously variable transmission (CVT), a type that works very well in stop-start urban traffic but which can feel very uninspiring in open road driving as the engine drones away at constant revs. And that was just the start of it. Peugeot came along with a diesel hybrid and Volvo topped that by showing off prototypes of its forthcoming diesel-based V60 hybrid, which is a plug-in as well, able to travel much longer distances than a normal hybrid in “electric only” mode after a charge from the mains. BMW’s ActiveHybrid cars, built around a turbocharged straight six petrol engine paired with an electric motor, showed that hybrids could be exciting, while several manufacturers started offering smooth, quiet electric cars, most notably Nissan with the impressive Leaf. And then, to cap it all, Chevrolet came up with the Volt, a range extender, or plug-in electric car that uses a charge from the mains for an initial 30 or 40 miles before an on-board petrol engine kicks in to generate enough electricity for hundreds more miles.

Now, though, Toyota is hitting back with a plug-in version of the Prius. The new car retains the petrol engine and hybrid drivetrain of the standard car but also uses a new lithium-ion battery pack and the option to charge from the mains in order greatly to expand the Prius’ envelope of electric-only operation. In fact, Toyota reckons it should be able to cover about 15.5 miles on power from the mains, rather than petrol from the pump, which could produce big savings if you do a lot of shorter trips. At the same time, thanks to its petrol engine, the plug-in Prius can also complete occasional longer journeys in hybrid mode, scoring a big advantage over pure electric cars such as the Leaf.

Drivers can choose from a variety of settings in order to modify the plug-in Prius’ behaviour. In HV (or hybrid vehicle) mode, it should provide a similar driving experience to a normal Prius, with the petrol engine cutting in and out when required. In EV (electric vehicle) mode, the plug-in Prius feels very similar to a pure EV such as the Leaf, with smooth and strong acceleration from rest and very low noise levels. Even with a full charge from the mains and EV mode selected, though, the plug-in will occasionally draw upon the petrol hybrid part of its drivetrain if you really put your foot down, but in normal driving you will just be running on battery power. This is in strong contrast to, say, BMW’s hybrids, which call upon their petrol engines very readily if you give the accelerator pedal more than the lightest tickle. A third mode, EV-City, allows even heavier use of the accelerator before the petrol engine comes into play, and an Eco programme can be selected in conjunction with any of the three modes in order to improve economy by dulling the car’s responses to the accelerator and adjusting the operation of the air conditioning.

In normal driving, without attempting to maximise battery range, I got just under fourteen miles out of the plug-in’s mains charge, and found the transition from EV to hybrid mode was very smooth. According to the car’s on-board computer, I achieved about 119 miles to the gallon over a test route of about 20 miles, but like the official PHEV figures given in the table, this is an impressive, but somewhat artificial result, as it depends heavily on the proportion of EV running you are able to achieve rather than the car’s underlying efficiency/economy – which, as the HV figures show, is pretty good too. Like every other Prius that ever turned a wheel, the plug-in offers a full range of geeky displays that allow you to monitor how its drivetrain is operating, including a readout for the all-important “EV Driving Ratio”, which tells you what proportion of a journey has been covered on electric power.

For me, though, what was almost as interesting as how the plug-in Prius behaved in electric-only mode was how it performed when the juice from the mains ran out and it reverted to working as a normal hybrid. When this happens, the plug-in should behave much as a normal Prius would but I thought it was a lot nicer than the last standard version of the car that I drove. It seemed altogether quieter, drastically reducing the annoyance factor from the CVT transmission - although that may also partly have been a by-product of the gentle, semi-urban route which Toyota had set up for testing. And while the plug-in still crashed a bit over bumps, its ride seemed rather better than that of previous Priuses as well, perhaps helped by the fact that it carries a little more weight, thanks to its larger battery, and rides on 15-inch steel wheels rather than big fancy alloys with big tyres to match.

At £28,345 (after allowing for the government’s £5,000 plug-in car grant) the plug-in Prius looks a bit pricey against mainstream diesels, but isn’t much more expensive than the standard car; that tops out at £24,910 if you opt for the most expensive T Spirit trim level, which provides a similar equipment list to the plug-in. It’s also a bit cheaper than the Chevrolet Volt. The sums probably won’t work if your pattern of driving is unsuitable, but if you mainly do short trips and also value the option of tackling occasional longer journeys in your main car, the likable plug-in Prius could be an attractive option.

Engine: 1.8-litre Atkinson cycle petrol engine combined with electric motor in hybrid drivetrain

Transmission: electric CVT

Power (petrol engine): 98BHP at 5,200rpm

Torque (petrol engine): 142Nm at 4,000rpm

Power (electric motor): 81BHP

Torque (electric motor): 207Nm

Fuel consumption (combined cycle, PHEV): 134.5mpg

Fuel consumption (combined cycle, HV): 84.0mpg

CO2 emissions (PHEV): 49g/km

CO2 emissions (HV): 84g/km

Top speed: 112mph

Acceleration (0-62 mph): 11.4 seconds

Price: £28,345 (after £5,000 plug-in vehicle grant)

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