Geneva show: Kia debuts hybrid powertrain tech
BY TIM NICHOLSON | 4th Mar 2014
The South Korean car-maker has not specified which models the hybrid system will power down the track, saying only that it will be available on new petrol and diesel production cars “in the near future”.
Kia has also used the Geneva expo to show off the full-electric version of its Soul hatch – a variant not on the agenda for Australia – and to preview its forthcoming seven-speed dual-clutch transmission that will replace its traditional six-speed torque-converter automatic across a range of models starting next year.
The new mild hybrid system was developed by Kia’s European research and development centre and features a 48-volt lead-carbon battery powering a small electric motor rather than a lithium-ion battery that is common in hybrid vehicles.
Kia says it chose this type of battery as it does not require any active cooling, can function better in sub-zero temperatures and is easier to recycle when the vehicle comes to the end of its life.
With the mild hybrid system fitted, a car can be driven in electric-only mode when driving at low speeds or cruising. The battery recharges during deceleration and braking at any speed.
Kia has also developed a new zero-emission automatic engine idle-stop system that uses a belt-driven starter generator instead of a conventional alternator to restart the vehicle with little vibration or noise.
The company says the battery supplies energy to an electric supercharger for increased power and torque at low speeds and that its engineers envisage the supercharger supporting a larger conventional turbocharger which would then take over for better power and torque at higher speeds.
Another option is for the hybrid system to be fitted without the electric supercharger for a more basic hybrid powertrain that Kia says would be ideal for smaller models in its range.
Engineers developing the system are targeting a reduction in CO2 emissions of about 15 per cent and the electric supercharger is set to increase power by between 15 and 20 per cent.
Kia produces a hybrid version of its mid-size Optima sedan range which is available in the United States, and while it is off the table for Australia at the moment, the company’s local arm has not ruled out introducing it in next-generation guise.
The mild hybrid system is likely to be suitable for cars as small as the Cerato all the way up to the new Sorento family-size SUV that is due to be replaced by the end of the year.
Also on display at Geneva is the full-electric version of Kia’s boxy Soul hatch that will go on sale in certain states in America, such as California, in the third quarter of the year.
Kia Motors Australia general manager of public relations Kevin Hepworth told GoAuto in February when the Soul EV was officially revealed that it is currently only built in left-hand drive and it was “highly unlikely” it would get a local berth due to a lack of infrastructure and low sales of EVs in Australia.
Kia’s newly developed dual-clutch transmission, on the other hand, is certain to make its way to Australia with new-generation vehicles, although it is still to be confirmed for the forthcoming redesigned Sorento due later this year.
The next likely recipient is the redesigned Optima expected here in the second half of next year.
Kia says the DCT has been developed “to balance greater fuel efficiency with improved performance and to deliver a sportier driving experience”.
The company’s engineers are pushing for a seven per cent improvement in fuel economy as well as a five per cent boost in 0-100km/h acceleration from the new transmission over the existing six-speed auto.
Engineers have also focused on improving NVH (noise, vibration and harshness) by using an external damper for greater refinement in the transmission.
The two dry clutches in the new transmission each feature an electric motor-driven clutch actuator to improve fuel efficiency and two gear input shafts for both even and odd gear ratios which allows the transmission to operate sequentially or to jump to any of the seven gears as required.
Kia claims the power delivery reduces the loss of torque during gear-shifting, making for a smoother ride. It also said the DCT will make for competitive fuel use and performance compared to rival dual-clutch transmissions.
