Using less fuel and reducing exhaust emissions have always been central to the concept of the Toyota Prius. With the all-new model Toyota has undertaken comprehensive re-engineering of its hybrid system and produced a ground-breaking aerodynamic design to take its signature efficiency to new heights.
As a result, CO2 emissions for the new model are from 70g/km, with average fuel consumption from 3.0 l/100km. This compares to the 89g/km and 3.9 l/100km achieved by its predecessor.
Changes to the hybrid powertrain are central to this achievement, including development of the 1.8-litre VVT-i Atkinson cycle gasoline engine to produce a world-best 40 per cent thermal efficiency. The detailed changes to the unit have reduced friction and mechanical losses, so a greater amount of energy can be obtained from every drop of fuel.
Elsewhere in the system all the major components have been redesigned or revised to save weight and improve efficiency, including the electric motor and power control unit.
A new nickel-metal hydride (NiMH) battery has been made more compact, yet more energy-dense, giving better performance and easier packaging – it is now located entirely beneath the rear seat, avoiding any compromise in trunk space.
The new Prius’ aerodynamics also makes an important contribution. The car’s lower, sleeker styling is sharper and more eye-catching, but at the same time more aerodynamically efficient. Toyota has succeeded in further improving the coefficient of drag (Cd) from 0.25 on the current model to 0.24. Both the bodywork and the under-floor area benefit from detailed elements that help smooth the flow of air over, under and away from the vehicle, reducing fuel consumption.