Kia to launch three-cylinder engine, DCT

The upcoming Geneva Motor Show will see the launch of Kia Motor's new three-cylinder 1-litre T-GDi Kappa engine as well as the company's first double-clutch transmissions (DCT).

 Kia claims the engine embraces the industry trend towards smaller capacity, higher efficiency units which consume less fuel and emit fewer emissions - while still delivering responsive performance.

The first car to benefit from Kia's new 1-litre T-GDi engine will be the new cee'd GT Line range. In this application, the new Kappa engine will develop 120PS and 172Nm torque. It has been engineered to deliver lower CO₂ emissions than the 1.6-litre GDi engine found in other cee'd models, pending homologation. In contrast, the Audi three-cylinder TFSI at this stage looks conservative as it develops 95PS and 160nm torque. But in terms of bhp/litre, Ford is up there among some others reaching for the stars with its latest Focus and a 2-litre EcoBoost engine of 125bhp/litre, as well as the 4x4 Focus RS with a 2.3-litre four-cylinder unit pushing out 139bhp/litre. Ford's 1-litre EcoBoost delivers 125bhp, which suggests how far some have yet to travel.

The new 1-litre T-GDi engine will be made available on a range of other Kia models in future.

The new power unit is the first of Kia's upcoming range of downsized engines to make its debut in Europe, and has been developed in-house by Kia's powertrain development team at its Namyang, Korea R&D centre.

Engineers' key aims throughout development were to provide immediate engine response, highly-efficient combustion and access to maximum torque from low engine speeds. These represent the cornerstones of Kia's wider strategy to develop downsized engines for its global model line-up.

Throughout the T-GDi's development, Kia's R&D teams have aimed for a 10 to 15 per cent improvement in fuel efficiency compared to the brand's current 1.6-litre GDi engine.

The new downsized engine features a newly-developed laser-drilled injector, with six individual holes. Instead of consistently injecting the fuel-air mixture onto certain points within the combustion chamber, the laser-drilled holes, laid out in a pyramid shape, provide a more even spread of fuel and air throughout the cylinder, according to Kia.

Backed by a high pressure pump, the new laser-drilled injectors are able to provide fuel injection pressure of up to 200 bar.

The adoption of a straight air intake port – instead of the gently curved port in Kia's existing 1.6-litre GDi engine – is said to further improve air flow to the combustion chamber for improved fuel efficiency.

The T-GDi's single-scroll turbocharger is paired with an electric waste-gate motor, which improves the turbocharger's performance with an efficient air scavenging strategy. As well as scavenging clean air for the engine to re-use for combustion, it is able to open the waste-gate at the same time to improve waste air flow.

This allows for greater low-end torque, more immediate engine response from any throttle position, and improved fuel economy under higher engine loads, according to Kia.

In the Kia cee'd GT Line, the engine's maximum 172 Nm torque is available across a wide 1,500-4,100 rev/min range, with maximum power arriving at 6,000 rev/min.

The engine is also fitted with an integrated exhaust manifold, which lowers the economy, lower temperatures also result in cleaner emissions by allowing the catalytic converter to operate more effectively.

The engine's temperature is regulated by a new dual-thermostat split cooling system. This allows the engine block and cylinder heads to be cooled independent of one another, the main thermostat controlling the flow of engine coolant to cylinder heads above 88°C to reduce knocking, and an engine block thermostat shutting off coolant flow above 105°C to reduce mechanical friction and aid efficiency.

  

                                         Double-clutch transmission

Kia engineers have also developed a double-clutch transmission, further following in the footsteps of Audi/Volkswagen.

The new DCT will be paired with the cee'd GT Line's 133PS 1.6-litre CRDi diesel engine. Capable of handling larger torque outputs than Kia's existing six-speed torque converter automatic (up to 300 Nm), the DCT's fast-shifting nature is suited to the new cee'd GT Line's sporty image.

Kia notes that drivers will benefit from faster gear changes than a traditional torque converter automatic transmission, as well as lower running costs.

Kia also anticipates that the new DCT will offer lower emissions and higher fuel economy, pending European homologation tests later in 2015. It will be made available on a wider range of Kia models in the future.

The new transmission is the first of its type from the brand, and like the three-cylinder engine, has been developed in-house by Kia's research and development teams at its Namyang, Korea R&D centre.

More fuel efficient than Kia's existing six-speed automatic transmission, the new DCT has been engineered with low fuel consumption and a sporty driving feel when in manual mode, and with comfort and smoothness when left in automatic mode.

Throughout its development, Kia's R&D teams targeted a three to five per cent improvement in acceleration (0 to 100 km/h) and five to seven per cent improvement to fuel efficiency, depending on model.

The DCT is made up of two dry clutches, each fitted with electric motor-driven clutch actuator to improve responsiveness, and an innovative hollow double-gear input shaft.

The hollow shaft allows the system to quickly engage even gears, while a solid shaft that runs through the centre operates odd gears.

This crossed gear shifting enables continuous power delivery and more efficient packaging, two development cornerstones for the engineering teams behind the project.

Kia claims the hollow shaft mechanism lets the DCT operate sequentially, the car anticipating the next gear that the driver is likely to need next under acceleration or braking, or jump immediately to any of its seven forward gears (and reverse). This is particularly useful under kick-down or heavy braking, allowing the driver to remain in control of the vehicle at all times.

The continuous power delivery of the DCT helps to minimise torque loss and forward motion by the powertrain during gear shifts, resulting in more decisive acceleration and a smoother drive.

Combined with a modest increase in power from 128 to 133 PS, the DCT's seven gears allow the GT Line's diesel engine to operate at its most efficient speeds. With the engine's torque increased from 265 to 285 Nm, the new DCT is engineered to effectively manage outputs of up to 300 Nm, achieving a better balance between the engine's improved, more effortless performance and potential for greater fuel economy.

Reduction of noise, vibration and harshness (NVH) has also been another area of focus for the development team. They devised an external damper to offer higher levels of refinement.

The cee'd GT Line will go on sale across Europe in Q4 2015, after which the new seven-speed DCT will be made available on a range of other Kia models.