Toyota's next-generation Prius eco-car is targeting advances well beyond improved fuel economy with greater emotional styling, a much more rewarding driving experience, and enhanced safety and driver assistance aids*.
Prius introduces the world's most thermally efficient petrol engine and the adoption of hybrid components that have been redesigned and relocated to make them more efficient, compact and lighter.
In a first for Prius, the Toyota New Global Architecture (TNGA) concept delivers a vehicle platform that results in a low centre of gravity and an increase in body rigidity of 60 per cent, securing much greater driving quality, ride comfort and quietness.
The hybrid battery is now stowed under the rear seat which, along with the new space-efficient double-wishbone rear suspension and the relocation of the standard 12V battery to the engine bay, has expanded luggage space to a maximum of 502 litres - equivalent to a mid-size car.
Petrol engine with world-leading thermal efficiency
Engineers have significantly improved the 1.8-litre VVT-i petrol engine, increasing its already high level of thermal efficiency to a world-leading 40 per cent, a figure comparable to a diesel engine.
Key developments include a Toyota-first dual cooling system, which automatically reduces the coolant flow volume in the engine to enable faster engine warm-up and the adoption of a low-viscosity oil to reduce friction between moving parts.
New piston and air intake port designs create greater tumble swirl inside the cylinder, and the volume of the exhaust gas recirculation has been increased, which further helps combustion performance.
Smaller, lighter hybrid components
The transaxle and motor have been redesigned, delivering a reduction in their combined weight. The motor itself is considerably more compact and gains a better power-to-weight ratio. Notably there is about a 20 per cent reduction in mechanical losses through friction compared with the previous model.
The transaxle has been made shorter by locating the drive motor and electric motor/generator over multiple axles, instead of the previous single axle. The planetary gear arrangement in the reduction gear has been replaced with parallel gears, which further helps to reduces losses.
The use of a loss-reduction device in the power control unit cuts losses by about 20 per cent. With a more compact design, the unit can now be positioned directly above the transaxle.
The nickel-metal hydride (NiMH) battery in Prius, considered by Toyota to be the optimum choice to meet market requirements, is more compact. The battery has been relocated beneath the rear seat, avoiding any intrusion in cargo space.
Australian homologated fuel consumption and emissions data will be announced closer to the vehicle's arrival in local dealerships from February next year.
The new Prius displays cutting-edge styling that has been designed to evoke a stronger emotional response. The TNGA chassis allows for lower lines, while retaining the signature Prius triangular silhouette.
The low horizontal axis flows back from the Toyota emblem at the front of the car, along the sides to the rear, emphasising the low centre of gravity and the upward sweep of the bodywork's curves. The forward-leaning belt lines and the unity of form generated between the cabin and the body add a sense of power and forward motion to the exterior.
Maximum body height has been reduced by 20mm and the high point of the roof has been moved 170mm forward, ensuring plenty of headroom for front seat passengers while also contributing to excellent aerodynamics and a class-leading 0.24 coefficient of drag (Cd).
The lower centre of gravity has also allowed the nose height to be brought down by 70mm and the rearmost section of the bonnet by 62mm, improving the driver's forward view.
Available new bi-LED headlamps use a single lens for both high and low beam operation. The units have a striking appearance that adds character and emphasis to the front of the car. The curved, triangular LED clearance lights also make a strong impression.
The rear of the car is another area in which the emotional quality of the new Prius design is evident, with defining lines extending from the rear spoiler through the combination lamps to meet the edges of the bumper. The result is both distinctive and aerodynamic.
The guiding principle for the interior design of the new Prius has been to combine the human sensibilities that have always characterised the model with a new sense of progressiveness and warmth. This can be witnessed in the overall openness of the cabin and the enveloping comfort provided for all occupants.
The new instrument panel has a slim, sculpted form, with optimum positioning of the gauges, displays and controls. White accents on the steering wheel and front console tray add to the impact and advanced quality of the design.
New seats have been created to provide more comfort and support and ease the strain of long journeys. The springs in the front seats have been set at the ideal angle to support the back and pelvis, reducing the burden on back muscles. Innovations in the materials and thicknesses used for the cushion pads help take the strain off the hips and create a more comfortable, snug feel for passengers.
Improvements have also been made to the cushioning of the rear seats and the seating area has been made wider, in order to match the higher comfort levels achieved in the front seats. Although the car's height has been reduced, this is not at the cost of space; in fact an innovative ceiling design has increased headroom compared to previous models.
Greater driving rewards, comfort and quietness
A lower centre of gravity and increased body rigidity deliver a safe and secure drive. Passengers enjoy a smooth, comfortable ride, with minimal roll.
The increase in body rigidity of more than 60 per cent, compared with the outgoing model, is achieved by using a ring-shaped, cyclical frame, laser screw welding (with a greater number of weld points) and structural adhesives. Together these contribute to achieving a more stable ride.
New Prius also uses a higher proportion of high-tensile strength steel in its construction in addition to high-strength, lightweight hot-stamp materials, achieving rigidity of 980Mpa and higher. The content of this quality of steel in the vehicle has increased from three to 19 per cent. Furthermore, the use of advanced Global Outstanding Assessment brings the benefits of light weight, stability and excellent collision safety performance.
The driving experience has been improved with better acceleration feel, achieved through an upgrade of the hybrid system control unit thanks to optimal use of the battery and electric motor.
The new Prius benefits from a drive assist system to provide a more responsive driving experience. When the driver selects the "power" mode, the adaptive system continuously monitors the vehicle's G-forces to understand driver behaviour and habits. The hybrid system responds to the driver's desire for more sporty performance, adjusting engine braking performance and throttle response.
The car's regenerative braking system has also been improved, with a new active hydraulic booster which gives quiet performance and controllability together with a natural braking feel.
Advanced safety and driver assistance systems
The new Prius will make a significant advance in active and preventive safety measures, including improvements to the adaptive cruise control, pre-collision and intelligent park assist systems as well as the introduction of blind-spot monitor and rear cross-traffic alert.
A new, intelligent parking sensor system will help avoid the kind of bumps that can happen during low-speed parking manoeuvres, regardless of accelerator and brake operation. It will also mitigate damage if contact does occur.
New features for on-board information and comfort
Toyota has improved the look and performance of the multi-information display in the driver's instrument binnacle. Data and images are now presented in full colour with high-resolution graphics on two 4.2-inch displays. The right-hand section presents speed, fuel level and other basic data and the left section is a multi-display where the driver can select preferred content using a switch on the steering wheel.
There is also a new colour head-up display which projects essential vehicle data and alerts on to the lower section of the windscreen, making information instantly and easily readable without the driver having to take their eyes off the road ahead.
The automatic air conditioning system uses an S-FLOW function to improve efficiency. It detects whether the front and rear passenger seats are occupied and adjusts ventilation and heating performance accordingly, minimising air flow around any empty seats. In addition to making the cabin environment more comfortable, this also improves fuel efficiency.