What is it?
Volvo’s people call this XC90 a Twin Engine, but if they really wanted to be that pedantic, they should have called it a Triple Engine.
This is the plug-in hybrid version of the new XC90, Volvo’s large SUV, and it arrives in early 2016, about six months behind the D5 diesel and T6 conventional petrol.
Like those versions it has a four-cylinder, 2.0-litre engine under the bonnet. Here it’s supercharged, for low-rev response, and turbocharged, for higher-rev response, and is engine number one. It drives the front wheels through an eight-speed automatic gearbox.
Engine number two is the one at the back. It sits neatly within the rear subframe and is an 81bhp electric motor driving the rear wheels.
It’s powered by a battery pack stored in the transmission tunnel, where there’s space because, unlike in other XC90s, there’s no propshaft. Plugging in the XC90 charges the batteries.
How engine two delivers its power is flexible. You can choose to drive on electric mode alone, where the range will be 24 miles. Or you can opt not to use it and save the battery power for later. Or ask for maximum input. Or choose a specialist 4wd mode for best traction off-road. Or, as is most likely, just let it sort it out itself.
If you want to get pernickety, there’s a third motor: a 25bhp starter motor/generator between the petrol engine and gearbox. It’s not much of an engine but it does pitch in from time to time, to smooth the transition between the different drive methods and fill any torque gaps.
What's it like?
Good, but there’s work still to be done. Volvo knows it, to be fair, and says it has time to sort what is, at the moment, sometimes jerky progress. The worst of it is extremely poor brake pedal feel, as it slips between regenerative braking and conventional braking.
It shows promise, though, and is brisk. What it lacks is the aural quality to match big, vee-shaped engines, but if you’re a sucker for a big engine, Volvo is content to admit that maybe it’s not the brand for you.
What is impressive is the 59g/km return on the official combined cycle - an anomaly of the current legislative cycle, as with most plug-in hybrids. Our route was too short to determine a realistic fuel return, but as usual, it’ll depend how you use the car. Commute 15 miles across town every day and you’ll never use a drop of petrol. Never plug it in and I’d be surprised if it bettered 30mpg.
What’s equally impressive on the T8 as other XC90s, though, is its interior, which is fantastically plush and comfortable, and still has decent accommodation in the two rearmost boot-placed seats, because the batteries sit in the transmission tunnel rather than under the boot floor as they do on some rivals.
Should I buy one?
It’ll take a specific set of circumstances for this XC90 to be the one for you, especially given how good the regular D5 is.
As is often the way with a plug-in hybrid, it’s the financial advantages or fuel benefits for a specific set of customers where it appeals most. But if the drivetrain is tuned properly between now and when it goes on sale, there’s no reason this XC90 shouldn’t be as good as the rest – and it’s an exceptionally good car.