Automotive Engineer

Low running costs play a big part in why consumers buy small cars. Fuel consumption and carbon emissions are relatively low, which is why more people – globally – are downsizing into the B-segment. But Europeans in particular value ride and handling too. If a vehicle is dull to drive, it’s going to be a hard sell, no matter how efficient it is. 

Kia has been successfully rebranding itself. Instead of being seen as a manufacturer of inexpensive vehicles, the firm wants to be known for making ones that perform as well as those from established OEMs in Europe.

Kia’s latest model is the B-segment Rio. To ensure that the fourth-generation model can compete with class benchmarks such as Ford’s Fiesta, the chassis was developed by vehicle dynamics engineers at the Rüsselsheim R&D centre in Germany.

“The Rio was tuned as a safe handling car with good ride comfort,” says Michael Lugert, Kia’s manager of steering and suspension for vehicle test and development. “Everybody wants good handling but nobody likes really stiff cars – a good compromise is needed.”

Much of the core engineering for Hyundai and Kia vehicles is done at the Namyang R&D centre in Korea, but an increasing share of development work is done at Rüsselsheim. It’s the OEM’s centre of excellence for diesel but is also expanding its activities in chassis, and the number of vehicle dynamics engineers is growing as the product portfolio expands.

Global reach

“Most of our models are sold all over the world but requirements for the domestic market or for the US are, of course, different to the European market,” says Lugert. “And that’s why our Korean colleagues, for example, work on the same projects but with different targets.”

Kia wants the Rio to be among the class-leaders, so benchmarking took in a selection of the most successful models in the B-segment and those highly rated by the press. Evaluation used a mix of objective and subjective measurements on the proving grounds and on the kinematics and compliance rigs at Rüsselsheim. Two models stood out.

“We always look to the best, and in this case we think the VW Polo and Ford Fiesta are very good cars,” Lugert says. “We don’t want to copy them, but to create our own character. And in the future – we’ve already started – create a DNA for our cars.

“I think the Polo is a very well-balanced car: we found a good compromise between ride and handling, and also steering. The Fiesta is more agile; that means more handling-oriented. It’s maybe a little bit too quick in response, so that is something that I didn’t want so much for our cars.”

The Rio’s basic platform is shared with its sister model the Hyundai i20. Both cars use the class-standard MacPherson strut front and torsion-beam rear suspension. To improve the ride over the outgoing model, Kia increased the wheelbase by 70mm to 2,570mm; the Ford and VW measure 2,489 and 2,470mm respectively.

Further improvements came from the rear-axle bushes – subtle changes can have a big effect on how the vehicle performs. B-segment vehicles work to strict cost targets – fluid-filled mounts were too expensive – so refinements to the longitudinal and lateral stiffnesses as well as damping properties and the design of the voids were needed.