With the exception of the Japanese domestic market (and limited production run) GRMN Turbo Edition, there's nothing exciting about the series production Toyota Yaris sold on either side of the Atlantic, but there sure is something special about the new Yaris Hybrid R Concept heading to September's Frankfurt Motor Show.
The study comes with a hybrid powertrain combining a 300hp 1.6-liter turbocharged four-cylinder gasoline racing engine that complies with the rules of the International Automobile Federation (FIA) and drives the front wheels, with a pair of 60hp electric motors sourced from the production Yaris Hybrid, each independently powering one of the rear wheels.
The two electric motors act as electric generators during the braking phase, and complement the petrol engine during the accelerating phases. The level of power delivered depends on the duration of energy delivery desired. For example, in road mode, the total power of the two electric motors is reduced to 40hp for maximum duration of 10 seconds per charge, while in track mode, the two motors reach a combined maximum power of 120hp for up to 5 seconds per charge.
In addition to providing power, the rear electric motors can improve the Yaris Hybrid R's handling characteristics during cornering by altering the distribution of torque between the left and right rear wheels, essentially achieving the same effect as an intelligent torque vectoring differential.
But that's not all as there's also a third 60hp electric motor mounted between the engine and the 6 gear sequential transmission, which 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.
According to Toyota, "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."
Together, the hybrid powertrain develops a total system output of up to 420 hp. Toyota didn't say if it plans to use this new system on racing or future production cars.