The Prius Plug-in can reach 84mph in electric-only mode and drive up to 39 miles, which is more than double the 14-mile range of its predecessor.
Officially, the new car can return 283mpg and emits just 22g/km of CO2 - the best figures yet achieved by any PHEV.
The car's lithium ion battery now has twice the capacity of the previous Prius Plug-in's, at 8.8kWh. This sends power through Toyota's new Dual Motor Drive System - one motor 22.5kW, one 53 - which represents an 83% boost in EV power over the old system.
This electric drive system works in conjunction with an 97bhp version of Toyota’s 1.8-litre four-cylinder petrol engine. A new exhaust gas recirculation system and improvements to its combustion make it, according to Toyota’s claims, the world's most efficient mass-produced petrol engine. With the electric motors, overall power is 120bhp.
Charging times have also been improved, thanks to an increase in the maximum power the car is capable of handling, from 2.0 to 3.3kW. The battery takes just two hours to charge up to 65% of capacity with a Type II Mennekes connector, or three hours and 10 minutes with a home plug socket.
Revealed at last year's New York motor show, the new Prius Plug-in looks little different to the regular Prius, but has a longer rear overhang, a higher rear spoiler and new LED lights front and rear. The car is 165mm longer than its predecessor, 15mm wider and 20mm lower with an impressive aerodynamic drag factor of 0.24, delivered by such sophisticated measures as a double-bubble rear window and an automatic radiator shutter which closes when cooling air isn't needed by the engine.
A gas injection heat pump system keeps the air conditioning working when the car is being driven in battery-only mode, while Business Plus models are available with optional solar panels on the roof that charge the battery when the sun shines - including when the car is parked and turned off.
‘More engaging’ driving position
Toyota is at pains to portray the Plug-in as a true driver’s car. It gets what designers call a “more engaging” driving position, a high centre console and the cabin layout of a luxury coupé, with a “dominant” centre cluster featuring 4.2in TFT screens and a wireless phone charging tray.
The driver-orientated theme continues with “more precise and responsive handling” thanks to a new double wishbone rear suspension, revisions to the familiar Prius’s MacPherson strut front end and a lower centre of gravity, which also reduces body roll, improves stability and sharpens the steering. The car is exceptionally quiet, Toyota says, helped by a new sound-insulating laminated screen and special front window glazing.
The plug-in Prius has never sold as well in the UK against the regular Prius, and the recent announcement of a reduction in the government subsidy for PHEVs won’t help this new model. But Toyota bosses believe demand could change “in a heartbeat” if CO2 outputs for cars in cities were dramatically cut, which they see as a realistic prospect.