As you would expect from a plug-in hybrid, this is not a car to be hustled. From the very first mile, the plug-in exhibits the same characteristics as its Ioniq siblings: it's laid-back and hushed, and it always seems to be caught by surprise when asked for maximum acceleration. But this relaxed demeanour won’t have come by accident, given that many buyers in this segment opt for electrified models for that very reason.
When fully charged, the car defaults to EV mode, where the motor does all of the work and the petrol engine only comes into life under heavy acceleration. It’s a shame that you can’t opt to stick with electric power for longer, because the engine kicks in earlier than seems necessary. But even with its occasional intervention, it's still easy to achieve an average miles per gallon that far exceed the trip computer’s 99.9mpg maximum readout. Hyundai claims that the batteries can offer 39 miles of range in this mode, although our urban test brought that figure closer to 30.
When left to make its own decisions in HEV mode, the electric motor does all the work when pulling away, before the petrol engine gently contributes as the speedo rolls into double digits. With gentle throttle applications it’s a seamless process, but ask for more power and the engine’s contribution can suddenly jolt acceleration with a gruff note to match. Keep the throttle pressed and the dual-clutch gearbox, despite being quick-shifting, does noticeably break apart acceleration, making the Ioniq Plug-in feel more conventional than the uninterrupted progress of the similar Prius. Drive with the flow of traffic and you’ll be rewarded with urban economy of around 55mpg.
Switch the gearlever across into Sport mode and the digital instrument cluster ahead turns red and swaps a speedo for a rev counter, with the speed displayed digitally beneath. The instant response of the electric motor does make the car feel quicker than the 0-62mph time suggests, but once you're rolling, progress remains at best steady. This, coupled with the car’s roly-poly suspension that still manages to vibrate over road imperfections, emphasises the car’s eco character.
As you'd expect, the satisfaction in driving the Ioniq Plug-in comes not from straining its hybrid powertrain, but from chasing high fuel economy and maximising range. The car’s digital instrument cluster permanently displays where energy is moving, showing when charge is being gathered by the regenerative system and when it’s being depleted under acceleration. Even when you're coasting the system can collect energy – we noticed a notch of extra battery charge reappeared when coasting down a hill for 20 seconds – showing how eco-friendly driving can have a significant impact on fuel usage in the Ioniq Plug-in.
Venture onto the motorway and road noise can get rather loud, especially over concrete surfaces, although the impact of this is perhaps heightened thanks to the lack of drivetrain noise. The fitment of adaptive cruise control and lane-keeping assist makes the scenario effortless, from a driver’s point of view, and we averaged more than 80mpg on a run at outside lane pace.
And what of the passengers? They certainly aren't short of space, with plenty of knee room in the back. Although, like in the Prius Plug-in, space for a middle rear passenger is narrow.