Kia revealed its all-new mild hybrid powertrain at the Geneva Motor Show in March. The powertrain is designed to simultaneously reduce emissions and improve engine performance in Kia’s next-generation models.
Developed by Kia’s European R&D centre, the new hybrid system employs a 48V lead-carbon battery, which powers a small electric motor to increase the engine’s power output and cut exhaust emissions. The development team behind the mild hybrid powertrain selected lead-carbon batteries over lithium-ion equivalents as they require no active cooling, are more easily recyclable at the end of the vehicle’s life and can function much more efficiently in sub-zero temperatures.
Kia’s mild hybrid system will enable a car to be driven in an electric-only mode at low speeds and when cruising, while the battery is recharged under deceleration at all speeds. In heavy traffic and on urban roads, the powertrain will also feature a zero-emissions stop-start system. Using a belt-driven starter’s generator – replacing the conventional alternator – the engine is able to restart with almost no noise or vibration.
The battery also supplies energy to an electric supercharger, which increases torque and power at low engine speeds. Engineers behind the development of the powertrain see the electric supercharger supporting a larger conventional turbocharger, which would seamlessly take over to provide greater power and torque as engine speeds rise. The new hybrid system could also be fitted without the electric supercharger for a simpler powertrain layout in smaller models.
In applying the technologies to production cars, Kia engineers are targeting reductions in CO2 emissions of up to 15 percent, while the electric supercharger is designed to deliver power increases of 15 to 20 percent depending on its application. The new mild hybrid powertrain will be available on new diesel and gasoline production cars from Kia in the near future.
Kia also used this year’s Geneva Motor Show as a stage to showcase its all-new seven-speed dual-clutch transmission (DCT), pointing the way for future transmission developments from the Korean brand.
The new transmission – the first of its type from Kia – has been engineered to balance greater fuel efficiency with improved performance and to deliver a sportier driving experience. Designed as a more fuel efficient replacement for Kia’s existing six-speed automatic transmission, currently available as an option on the majority of Kia models, the new DCT combines the advantages of both manual and automatic transmissions while allowing for faster gear changes then both.
Throughout the development process, engineers have been targeting a seven percent improvement in fuel efficiency and a five percent improvement in acceleration (0-100kph) over the existing six speed DCT transmission.
The new seven-speed dual-clutch transmission will start to appear on production Kia cars in 2015.