A novel hybrid-electric powertrain debuting on the 2017 Kia Niro subcompact CUV targets sub-90 g/km CO2 emissions and combined highway/city 50 mpg fuel economy.
“Niro’s combination of gasoline direct injection, Atkinson cycle, and cooled exhaust gas recirculation engine technologies along with a dual clutch transmission — all electrified — is an industry first,” said Steve Kosowski, Kia Motors America’s Manager of Long Range Strategy.
Kosowski and other Kia product development officials spoke with Automotive Engineering following the all-new Niro’s world debut at the 2016 Chicago Auto Show. They explained that Niro was designed from a clean sheet as a hybrid vehicle, with a plug-in version coming at a later date. Niro shares its Hyundai engineered 1.6-L Kappa-family 4-cylinder engine and its six-speed DCT with the Hyundai Ioniq. It also shares that new sedan's 103-in (2616-mm) wheelbase and track widths.
According to Kosowski, Niro's IC engine delivers 103 hp (77 kW) at 5200 rpm, and achieves 40% brake-thermal efficiency. The DCT is unique among four-door hybrids, including the 2016 Toyota Prius and Ford C-Max, which use continuously variable transmissions. Fitted in the P2 position between Niro's engine and transmission is a 43-hp (32-kW) permanent magnet AC synchronous motor. It's powered by a 240-V lithium-ion polymer battery with a rated power density of 42 kW and an energy capacity of 1.56 kW·h. The combination motor-engine produces an estimated 146 hp (108 kW) and 195 lb-ft of torque (264 N·m).
In another interesting technology move, the lithium battery pack also provides power for the headlights, windshield wipers, and other traditional 12-V battery tasks, according to Orth Hedrick, Kia Motors America’s Vice President of Product Planning. “The power control module and the energy control module essentially act as a transformer to step down the battery power that’s needed to drive the 12-volt circuits on the vehicle,” explained Hedrick.
Elimination of the conventional 12-V lead-acid battery saved weight as did other mass management initiatives. Advanced high strength steel accounts for 53% of Niro’s body structure, including roof rails, and A- and B-pillar reinforcements. The lightweight steel is also used for the seat frames. The hood, tailgate, front bumper, and many suspension parts are aluminum, while the foot park brake pedal is made of fiberglass reinforced plastic.
Niro’s Eco-DAS (Driver Assistance System) spotlights Kia’s first application of Predictive Energy Control. According to Hedrick, the vehicle’s three-dimensional navigational system and the cruise control system are used in tandem to anticipate and react to topographical roadway changes.
“The system knows the elevation changes on your chosen destination, so it can anticipate when to use the battery and when to use the traction motor as much as possible to get a higher mileage benefit,” said Hedrick, noting a potential 3% fuel economy boost.
Kosowski said Eco-DAS can apply energy management logic during uphill drives—a unique Kia feature, he claimed. "There are systems on some German luxury vehicles that can manage the powertrain response in downhill driving, but not in uphill driving. Kia’s system can apply the traction motor’s regenerative braking captured kinetic energy while going uphill to save fuel,” Kosowski noted.
Concept Niro debuted at the 2013 Frankfurt Motor Show as a two-door, B-segment CUV. The four-door production Niro is a C-segment vehicle styled by Kia’s design centers in California and South Korea. Lead product development work was done in South Korea with contributions from U.S. engineering teams.
All-wheel drive Niro’s 25.5 ft3 (722 L) of cargo space is larger than that of the Ford C-Max Hybrid and the Toyota Prius, according to Hedrick, “thanks to efficient packaging of the battery beneath the rear seat.”
Estimated combined city/highway U.S. fuel economy is 50 mpg. Actual fuel economy and pricing will be announced closer to the production launch. The 2017 Kia Niro hybrid utility vehicle arrives in dealerships outside the U.S. sometime in 2016 with the U.S. arrival anticipated in early 2017.