2013 Frankfurt MS: Fuel cell
DEDICATED TO MAXIMISING DRIVING PLEASURE
Making its World Premiere at the 2013 Frankfurt Motor Show, the Yaris Hybrid-R concept car combines the advanced technology of the compact volume seller Toyota Yaris Hybrid with high-performance engineering inspired by Toyota's racing prototype, the TS030 HYBRID, which participated at Le Mans and in the World Endurance Championship. The result is a highly focused concept car dedicated to maximising driving pleasure on road and on track.
Hybrid technology is still young - with the first generation Toyota Prius appearing in 1997, just 16 years ago. As such, it still has its future ahead and a great potential to evolve in many different directions. Only recently, hybrid technology has started to appear in racing programs, but is not yet fully established in people minds as a performance oriented solution. The Yaris Hybrid-R concept car is a clear showcase of possible ideas for the development of hybrid technology for maximum performance and increased driving pleasure.
The Hybrid powertrain
Based on the Yaris 3-door, the Yaris Hybrid R concept hybrid powertrain configuration, employs a powerful and highly tuned 1.6l petrol engine combined with two powerful electric motors to provide an 'intelligent' electric four-wheel drive capability.
The front wheels are driven by a 300hp 4-cylinder 1.6 turbo engine with direct injection specifically developed by Toyota Motorsport GmbH (TMG) according to the rules of the International Automobile Federation (FIA) for a Global Race Engine to be utilised in different motorsport disciplines.
At the rear, each wheel is individually powered by a 60hp electric motor — the same as those used in the standard Yaris Hybrid. The hybrid powertrain system develops a total system output of 420 hp.
The two electric motors work as electric generators during the braking phase, and supplement the petrol engine during the accelerating phases.
Just like in the TS030 HYBRID, the energy recovered during the braking phase is stored in a super capacitor. In the Yaris Hybrid-R it is located under the rear seat, where the Yaris Hybrid battery is usually positioned. Compared to the standard NiMh hybrid battery, the super capacitor has a higher power density and a fast power charge / discharge speed. It is perfectly suited to the requirements of sporty driving on track, which requires brief and immediate bursts of power.
A 3rd 60hp electric motor, located between the engine and the 6 gear sequential transmission, operates as a generator in two different cases: during deceleration to feed the super capacitor and during acceleration to directly power the rear electric motors.
The latter will only happen when the engine power and torque exceed the grip potential of the front wheels. The generator behaves like an advanced traction control system, redirecting the torque as electric energy to the rear wheels, to boost the acceleration and improve the handling rather than to simply limit the engine power.
A resolutely sporty design
The Yaris Hybrid-R features a more aggressive and emotional interpretation of the design language that characterises recent Toyota models. The Keen Look and Under Priority design philosophy is reinforced by the adoption of newly designed headlights, a wider front grille and black and blue details that contrast with the white body colour.
The specific bumper design incorporates two large air intakes and blue LED daytime running lights. The intakes greatly contribute to the front brake cooling, while the shape of the lower lip is designed to centrally channel underbody air flow.
The flared fenders house bespoke 18-inch TRD wheels fitted with 225/40 R18 Michelin Pilot Sport Cup tyres featuring an asymmetrical tread design to complement the Yaris Hybrid-R sporty philosophy. Ideally suited for a mixed use on the road and on the track, this choice of high-performance tyre is a symbol of the fruitful cooperation between Michelin and our racing team involved in the World Endurance Championship series.
Grooved and perforated brake discs are gripped by six-piston callipers in the front and four-piston callipers in the rear. Located on the rear pillar, a quick opening fuel cap makes easier a quick refuel in the pits.
At the rear, Yaris Hybrid specific LED lights maintain the link with the production car. An exclusive spoiler is mounted on the roof and the redesigned bumper incorporates a large diffuser, with an exhaust pipe framed by two air extractors.
A racing cockpit
Matching the colours outside, the dual tone Recaro bucket seats feature black leather side bolsters and blue Alcantara®. The same blue Alcantara® covers part of the door panels and the dashboard to give the interior a more cohesive, racing-inspired feel.
Ideally located high and close to the driver's right hand, the shift lever of the sequential gearbox is set up to quickly change down gears by pushing the lever forwards, and to change up by pulling it back.
The sport steering wheel wrapped in Alcantara® welcomes a racing inspired push button to select, at rest, either the "Track" or "Road" mode, or while driving , the "Boost" function.
The driving position is ideally completed by a set of GT 86 sport pedals.
A 'Road' mode for day-to-day driving
The 'Road' mode is characterized by a reduction of the engine output and an appropriate management of the amount of energy the super capacitor can distribute to reduce fuel consumption and CO2 emissions. Accordingly, the turbo compression ratio of the 1.6l engine is reduced and the injection / ignition mapping adjusted.
The hybrid system works seamlessly with the 1.6 turbo petrol engine, especially during start-up phase at low rpms when the efficiency of the conventional engine not yet optimum. The super capacitor can release the energy recovered under braking for a maximum duration of 10 seconds, while the total power of the two electric motors is limited to 40 hp. To maintain a sufficient state of charge in the super capacitor, the third electric motor can be used at any time as a generator.
Depending on the state of charge of the battery, the Yaris Hybrid-R may also operate in full electric mode for short distances, especially during parking operations.
A 'Track' mode for track days
The 'Track' mode makes full use of the maximum system output of the engine and a performance oriented energy management. The 1.6 turbo engine develops 300 hp and provides maximum torque of 420 Nm, while the rear electric motors can reach a combined maximum power peak of 120 hp for up to 5 seconds.
At low speeds, or in a curve, when the engine power and torque exceed the grip potential of the front wheels, the third electric motor can directly power the rear electric motors. The generator behaves like an advanced traction control system, redirecting the petrol engine extra amount of torque as electric energy to the rear wheels.
Rear electric motors - one per wheel — can greatly influence the Yaris Hybrid-R handling characteristics during cornering by altering the distribution of torque between the left and right rear wheels.
Each engine can be used independently as a generator or a motor to achieve the same effect as an intelligent torque vectoring differential.
Depending on the radius of the curve, the system can send more torque to the outside rear wheel allowing higher cornering speeds into the corner (middle-speed curves), apply more braking force to the inside wheel (fast curves), or even brake and accelerate each wheel independently (slow curves) to adjust the yaw effect for a better line, to limit steering angle, and understeer.
With the particularly high system output of its hybrid powertrain, an energy management system strongly oriented towards the reach of maximum performance and the utilisation of the engines for better handling, the Yaris Hybrid-R concept indicates a potential direction for the development of hybrid technology towards more driving pleasure. t