2016 Toyota Prius longer, leaner, and more efficient

The 2016 Toyota Prius will be longer, leaner, and more efficient than its predecessor when it hits dealers, according to the Japanese automaker.

The Prius' completely redesigned 1.8-litre engine has a 40 per cent improvement in thermal efficiency, which is partially attributed to a large-volume exhaust gas recirculation (EGR) system and improvements in combustion efficiency.

The transaxle and electric motor have also been redesigned, and are lighter—Toyota won't say by how much—while delivering a 20 per cent reduction in mechanical losses through friction compared to the previous model.

Toyota said the planetary gear arrangement in the reduction gear has been replaced with parallel gears, which further helps loss reduction.

A loss-reduction device in the power control unit cuts losses by about 20 per cent, and can now be positioned directly above the transaxle, keeping the overall size to a minimum, while the energy density of the available lithium-ion and nickel-metal hydride batteries has been boosted.

All told, Toyota expects a 10 per cent improvement in EPA-estimated fuel economy, with an Eco model that will "achieve an even greater improvement."

The 2016 Prius, built on the Toyota New Global Architecture (TNGA), delivers 60 per cent more torsional rigidity compared to the outgoing version, while the amount of high-tensile strength steel used in the car has increased from three per cent to 19 per cent.

Overall, the Prius' height has been reduced by 20 millimetres, while the high point of the roof has been moved forward by 170 millimetres.

The nose height has also been dropped by 70 millimetres.