There are not many vehicles that can claim being “game-changers” like the Toyota Prius can. The Prius was the first hybrid to be mass-produced when it was launched in Japan in 1997, making hybrid technology readily available to the car market. However, it was only with the launch of the second-generation Prius in 2005 that South Africa first tasted hybrid technology.
In keeping with the Prius name – which means “front runner” in Latin – the new-generation marvel continues to build on its green car credentials and now comes with even more technical breakthroughs to reaffirm its status as the world’s best-loved hybrid. In fact, Toyota had sold more than 3.5 million Prius hybrids before the launch of the fourth-generation model. In the past three generations each Prius had a defined role to play.
For example, the first-generation Prius created the hybrid vehicle market, the second generation raised the model’s popularity with a more advanced image, and the third generation secured mass-market success, helping Toyota progressively roll out hybrid power to its mainstream model ranges.
The new Prius is the first model to use a chassis based on Toyota New Global Architecture (TNGA). It will also underpin other future models and will be joined by further platforms suitable for different vehicle applications, from compact sports cars to SUVs.
The TNGA platform plays a defining role in the Prius’s essential fun-to-drive quality, giving the car a lower centre of gravity compared to the current model, and securing a more engaging driving position and more precise and responsive handling, with less body roll. This means better handling can be achieved directly from the quality of the chassis and body without having to use firmer suspension settings, or compromising ride and comfort.
It makes a big contribution to the improved driving dynamics – beyond what might be expected of an eco-car.
The new Prius is not simply “another green car,” its design and high quality throughout give it greater emotional appeal and a powerful, desirable presence, underpinned by the fundamental strengths of the new TNGA platform. As Toyota’s most advanced hybrid, it is appropriate that it is an image leader and the intention has been to produce a design that makes an immediate impact.
The new Prius has a unique aerodynamic treatment to the rear section of the roof, which supports the clean flow of air over and away from the vehicle. The length and angle of the rear spoiler have been precisely calculated and the bodywork tapers towards the rear corners, helping smooth airflow and reduce drag. The low roof and rear pillars are distinctively integrated using blacked-out panels that are shaped to draw air around the side windows to the rear of the car.
Other aerodynamic aids include graduated vertical channels each side of the windscreen that direct airflow and rain water up and over the roof without generating wind noise. Aero stabilising fins are featured on the front quarter light trim and rear combination lamp housings, which control air turbulence along the side of the car. The new TNGA platform is also designed for the smoothest possible airflow beneath the car.
In combination, the car’s low wind resistance features secure a world-class 0.24 coefficient of drag.
The rear end design flows strongly from the rear spoiler down through the bumper, with the wheel placement further emphasising the car’s firmly planted stance. The slim, striking combination lamps have been moved to the outer edge of the car, following a sharp angle that is accentuated by the distinctive, unbroken line of the red LED tail lights.
The cabin has a strong design that is advanced, functional and makes a big visual impact. It inherits the intuitive concept of previous Prius generations by consolidating operational functions closest to the driver and placing the information functions further away. The functionality of this approach can be seen in the layered construction of the dashboard with distinct control and display zones.
The dashboard wraps gently around the driver and flows almost seamlessly into the door panels. The number of different parts that make up the instrument panel has been reduced, for example the piano black section is now a single unit. This creates a strong visual contrast with the areas of the dashboard and door panels, finished in a high-quality white material that is scratch-resistant.
The dominant centre cluster has a silver-finish frame and a “floating” design, created using a sculpted and near-invisible rear mounting. The seven-inch touchscreen panel is designed like a tablet and allows intuitive operation of the audio, including “flick” actions to scroll through the displays. The standard six-speaker audio package gives rich and clear sound quality.
The instrument cluster features dual 4.2-inch full colour TFT (thin film transistor) LCD screens with easy to read displays. The screen nearest to the driver presents vehicle speed and ancillary information such as fuel level, odometer, trip meter, driving range, average fuel consumption, outside temperature and drive mode. The background colour changes according to the drive mode selected: blue for ECO, grey for Normal and red for Power. The second screen provides information about the hybrid system and eco-driving tips and performance, together with multimedia and climate control system details and driver assistance alerts.
There is plenty of standard safety kit too, including rear-view camera with dynamic guidelines and no fewer than seven airbags (curtain, front, side and a driver knee airbag). Convenience features include customisable dual Multi-Information Display screens and seat heaters for driver and front passenger. The new Prius also boasts a Toyota-first full-colour Heads Up Display (HUD) projected directly to the windscreen.
A reduction in the steering column angle from 24 to 21 degrees, a lowering of the driver’s hip point by 59mm and a new seat design all help create a more natural and engaging driving position. The range of tilt adjustment has been increased, to accommodate a wider range of driver heights.
The front seats have been completely redesigned to offer more comfort while at the same time saving weight and space. They offer a snugger fit, with better body holding that helps reduce fatigue on long journeys. The rear seats have also been revised for greater comfort and benefit from an improved armrest and cup holder.
The New Prius introduces the next generation of Toyota’s signature hybrid powertrain, the first in a new family of powertrains that builds on the two pillars that have made Toyota hybrids popular with drivers across the globe: on the one hand their fuel efficiency, and on the other the relaxed and carefree drive that they provide.
Toyota has focused its efforts on making this next generation of hybrids even easier and more intuitive to drive. The system has been set up so that it gives a natural, immediate, but smooth response to any accelerator pedal input.
The new hybrid battery offers higher energy density. At the same time as maintaining power output, its size has been reduced by 10%. Furthermore, it can now absorb 28% more energy in the same amount of time, which means that it is faster charging. The electric motors are smaller in size, yet also provide a better power-to-weight ratio, and the thermal efficiency of the petrol engine – at 38.5% already very high on the current Prius – is increased to 40% – a world’s best for a petrol unit.
As in the current model, Prius’s hybrid system features a 1.8-litre VVT-i Atkinson cycle petrol engine. However, the unit has been completely re-engineered to deliver significantly better fuel economy. The engine’s maximum output of 72kW is delivered at 5,200rpm, with peak torque of 142Nm at 3,600rpm.
The new Prius has a redesigned transaxle that offers more efficient performance and packaging and reduced weight. Its smaller dimensions, notably a 60mm decrease in length, have allowed the auxiliary battery to be relocated to the engine compartment.
The transaxle houses four components: two electric motor-generators (MG1 and MG2); a single planetary gear; and a reduction gear to the final drive. MG1 serves primarily as a generator, converting any surplus power from the petrol engine into electricity, which can be stored in the HV battery. It also serves as the engine’s starter motor. MG2 is the electric drive motor, which also acts as a generator when the car is in regenerative braking mode. It drives the car from start-up, at low speed and in EV (electric vehicle) mode and is the sole propulsion method when the vehicle is in reverse.
Updates to the hybrid system software allow the new Prius to draw more on its electric drivetrain, allowing it to accelerate in a low engine rev range. It has also permitted the speed range of the electric motor to be increased by 60%, compared to the current model. This means there is less dependency on the petrol engine at higher speeds, improving fuel economy.
The two motor-generators are all-new and are smaller and lighter than before to suit the new multi-shaft transaxle design, with no negative effect on fuel economy.
Higher motor speed and new forced water-convection cooling in place of air cooling improve the efficiency of the electric-drive motor (MG2), which delivers 53kW of power and 163Nm of torque.
The nickel-metal hydride (NiMH) battery is more compact, so can be located entirely beneath the rear seats, avoiding any intrusion in the load space.
Every aspect of the hybrid system has been made more efficient and these improvements deliver about half the gain that’s been realised in fuel efficiency. The petrol engine uses less fuel; the electric motor-generators are smaller, lighter and more efficient; mechanical losses in the transaxle have been cut by 20%; the power control unit is more efficient; and the nickel-metal hydride HV battery is lighter and more efficient. Further gains have been made by reducing the energy load of the air conditioning system, improving the rolling resistance performance of the tyres and creating a more aerodynamically efficient vehicle design.
The driving experience has been improved with better acceleration feel, achieved through an upgrade of the hybrid system control unit. Optimal use of the battery and electric motor have minimised the “rubber band” feeling when accelerating – the sense of a delay in acceleration when you press the throttle.
The new Prius accelerates from 0-100km/h in 10.6 seconds. Highway overtaking acceleration from 80 to 120km/h can be accomplished in just 8.3 seconds and the top speed is 180km/h.
The new hybrid system’s output – petrol engine and electric motor combined – is 90kW, and the drivetrain now delivers its power in a more user-friendly manner. The new Hybrid System allows the system to draw more on its electric power, which means that acceleration feels more natural with the engine revs building up gradually as the car picks up speed.