Toyota Prius Showcases Cutting-Edge Hybrid Tech

Toyota Prius Showcases Cutting-Edge Hybrid Tech

Toyota Kirloskar Motor recently hosted a special preview of the 2017-model Prius, which the company plans to launch in India in Q1, 2017. At the 'Toyota Caravan' event held at the Jawaharlal Nehru Stadium in New Delhi last month, TKM reiterated its commitment towards cleaner, greener and more sustainable mobility for India and the Prius preview was a part of that initiative. Toyota, which launched the Camry Hybrid in India back in 2013, has sold more than nine million hybrid cars globally and currently sells as many as 33 hybrid car models in more than 90 global markets. With the Camry already doing well in India, TKM hopes to further increase the uptake of hybrid cars with the launch of the 4th generation Prius in India next year. Let's take a closer look at this cutting-edge hybrid vehicle and see what it offers in terms of technology.

POWERPLANT AND TRANSMISSION

Toyota was the first of all global manufacturers to take the lead with production-spec hybrid cars with the launch of the first-generation Prius, which happened twenty years ago. Now in its 4th generation, the Prius is available in as many as eight different versions in different markets worldwide and with its amazing real-world mileage figure of up to 24 km/l, the Prius takes the lead with car manufacturers' push for boosting efficiency.

The new, India-bound Prius is equipped with Toyota's 'Hybrid Synergy Drive,' which combines a 1.8 l four-cylinder petrol engine with two electric motors, with power going to the front wheels via an electronically controlled planetary-type continuously variable transmission (CVT). As befits the high-tech Prius, its CVT uses shift-by-wire technology, which is fully computer controlled and is fine-tuned to maximise efficiency during all driving conditions. However, for those who cannot do without shifting gears on their own, this CVT offers the option of using dash-mounted shift paddles for manual shifts, using pre-determined 'gear ratios.'

Coming back to its hybrid powerplant, the 4th generation Prius uses hybrid components that are lighter and smaller than components used in earlier versions. Also, new, more powerful lithium-ion hybrid batteries have replaced the earlier car's nickel-metal hydride batteries (on all models of the Prius except the standard-grade Prius Two). The new battery's smaller size allows it to be positioned under the rear seat rather than beneath the luggage area, which provides more luggage space for the user.

The Prius' hybrid powerplant boasts a total system output (from the petrol engine plus twin electric motors) of 121 hp and 142 Nm of torque, which is more than enough for most driving circumstances. The car lets the driver choose between 'Normal' and 'Power' driving modes. Normal mode provides the best balance between fuel economy and power delivery, while Power mode gives top priority to performance, hence providing stronger acceleration. Remarkably, the car's 2ZR-FXE 1.8 l petrol engine achieves more than 40 % thermal efficiency, which is due to reduced internal friction, improved combustion and Toyota's Exhaust Gas Recirculation (EGR) system, which quickly brings up engine coolant temperature to optimum levels. Toyota claims that this engine not only provides unprecedented efficiency, but also has reduced NVH characteristics compared to the older unit found on earlier Prius models. Increasing overall efficiency even further, the Prius' regenerative braking system conserves energy when the vehicle is slowing down. It does this by switching the electric motor into a generator, to recover the wheels' kinetic energy as electrical power and then storing it in the battery.

pg-52-55 atrDec16 2

CHASSIS AND SUSPENSION

The Prius makes use of Toyota's 'New Global Architecture' (TNGA), which incorporates a high-strength body structure, independent double-wishbone rear suspension, and a lower centre of gravity for better handling. Indeed, according to Toyota, the TNGA platform's structural strength has made a significant contribution to the new Prius' improved ride quality, steering response and handling prowess.

Hot-stamped, high tensile steels that allow for complex forms, which are lightweight and strong, are used extensively throughout the Prius' body. While innovative fastening methods like laser screw welding and advanced adhesives contribute to structural strength, Toyota has also worked hard towards reducing the vehicle's weight, with aluminium components like the hood, rear doorframes and brake callipers helping with the car's weight loss program. Along with the independent MacPherson strut suspension with stabilizer bar at front, the new double wishbone rear suspension, which replaces the earlier car's torsion beam type setup, also helps improve handling, while the car's 17-inch alloy wheels, shod with low-rolling-resistance tyres, provide sufficient stability and grip at higher speeds.

COMMITMENT TO SAFETY

While the Prius is one of the most fuel efficient cars around, it's also one of the safest. The Japanese company's 'Toyota Safety Sense P' (TSS-P) driver assist technology is now standard on all versions of the Prius, and uses millimetre-wave radar and a monocular camera sensor to help detect pedestrians, vehicles, and lane markers in the car's operating environment. TSS-P is designed to identify such obstacles in the car's path, and in the absence of driver-initiated action, automatically applies the brakes if necessary, in order to avoid a collision. TSS-P includes the Pre-Collision System with pedestrian detection, lane departure alert with steering assist, and dynamic radar cruise control.

Braking has been made safer, too. Step on the brake pedal in the Prius, and in place of the conventional cable, an electronically controlled system interprets braking pressure into electrical signals and applies an appropriate amount of braking force through an active hydraulic brake booster. This system also coordinates between the hybrid system's regenerative braking and hydraulic brake force to provide optimal performance and feel.

A full array of SRS airbags, including driver and front passenger airbags, driver and front passenger side airbags, full-length curtain airbags, a driver's side knee airbag, and a front passenger seat cushion airbag, mean that the Prius cabin is one of the safest places to be in the unfortunate event of an accident.

pg-52-55 atrDec16 1

DESIGN AND INSTRUMENTATION

Toyota engineers have made the Prius as aerodynamic as possible and its 0.24 coefficient of drag (Cd) is among the lowest of all current production cars. This has been achieved with the vehicle's shape as well as by using detail touches like an automatic-shutter front grille (which reduces drag by closing, when airflow to the radiator is not required) and stabilising fins on the underfloor covers.

The Prius also features new Bi-LED headlamps, with automatic headlamp levelling, which keeps the beams focused on the road and helps reduce or eliminate inconvenience to drivers in oncoming vehicles. The vehicle's new, larger, rear door glass, larger fixed rear quarter windows and a full-width glass panel beneath the rear spoiler provide better visibility from the cabin, while a backup camera, standard on all versions of the Prius, provides useful assistance while reversing.

Inside, the new Prius gets high-tech digital instrumentation, with dual 4.2-inch full-colour TFT multi-information displays, which can be controlled via buttons mounted on the steering wheel. The display has driving mode-dependent colour themes (red for Power mode, blue for Normal mode) and information displayed includes vehicle speed, fuel remaining, drive mode selected, outside temperature, odometer functions and driving range. The driver can also choose to have the system display additional information like fuel economy and hybrid battery state of charge.

NVH reduction and near-silent operation was a key focus area for Toyota engineers and the Prius' interiors feature a special sound-insulating laminated windshield, as well as multiple sound absorbers in the dash structure which reduce noise intrusion into the cabin. Some variants also get sound-insulating laminated front door glass, carpeting backed by a thick silencer pad, a urethane-based headliner, and ribbed structure for the front pillar trim, all of which absorb sound almost completely, leaving the car's occupants in a silent, safe and peaceful cocoon.

A car's air-conditioner is of utmost importance in the Indian context, and the Prius' unit is smarter than most cars' ACs. The AC unit, which uses a quiet electric compressor for maximum efficiency, directs airflow only to seated occupants, which conserves energy and maximises comfort. Some versions of the Prius also get heat-insulating IR-cut windshield glass, which substantially reduces the intrusion of infrared rays inside the cabin, enhancing comfort and reducing the air-conditioning system's workload.

CONNECTIVITY AND DRIVER ASSISTANCE

As you might expect, the Prius offers full smartphone connectivity and even offers wireless charging for compatible devices. There's an AM/FM/CD player with six speakers, USB 2.0 port, advanced voice recognition, hands-free phone capability, phone book access and music streaming via Bluetooth.

Some versions of the new Prius also get HD radio, HD predictive traffic and weather overlay, 8-speaker JBL audio system and Intelligent Parking Assist (IPA), which uses ultrasonic wave sensors for automatic parallel parking. Toyota's Intelligent Clearance Sonar (ICS) system provides audio-visual warnings if the driver gets too close to detected obstacles on the vehicle's sides, which is useful in tight parking spaces.

SUMMARY

Given its high-tech hybrid powerplant, that uses a fuel-efficient 4-cylinder petrol engine along with twin electric motors (one primarily for propulsion, the other for generating electricity, which charges the batteries), the Prius is no ordinary vehicle. The car represents cutting-edge hybrid vehicle technology – the best that Japan can currently offer. It's not just a car, the Prius is also a preview of things to come in the near future, as electric power gradually takes over from the IC engine.

Whether or not India is ready to for an advanced hybrid vehicle, and whether the Prius' excellent fuel economy is enough to offset its initial purchase price (no official word on the exact price yet, but we it's likely to be stratospheric!) remains to be seen. Then again, maybe these things don't even matter. For those who want a best-of-the-breed hybrid and for whom cost is not a constraint, the Prius showcases current state-of-the-art hybrid technology like few other vehicles on this planet can. And for that reason alone, we wholeheartedly welcome the Prius to India.

TEXT: Sameer Kumar