Many components have been shrunk and lightened by as much as 20% to aid the car's quest for economy. The battery pack is the only largely unaltered part of the powertrain.
Toyota is sticking with nickel-metal hydride batteries, because it remains to be convinced of the safety and long-term reliability of the lithium-ion packs favoured by other manufacturers working on hybrids and all-electric cars. Once again, the Prius recharges its batteries on the move.
Using a continuously variable automatic transmission again, the Prius now offers three operating modes: EV, which puts it onto battery power alone; Eco, which helps the driver get maximum economy; and Power, for greater throttle sensitivity. There's a multi-information display in the instrument cluster, giving details of fuel consumption, energy flow and how the hybrid system is functioning at any given time.
From the air-conditioning system to the lights, Toyota has looked at ways of minimising the power drain on the engine and batteries to eke out maximum fuel economy and cut CO2 emissions. Exhaust gases are used to help warm the engine to its most efficient operating temperature more quickly, while there are no power-sapping belts driving off the engine.
The air-conditioning system is the first in the world to work on battery power alone, and even the water pump is electrically operated.
One of the options is a 'moonroof' with solar panels to keep the batteries charged. It can provide enough power to drive a fan that will keep the cabin at a constant temperature even when the car is parked.
Low-energy LED dipped-beam, tail- and stop lamps are also available.