- By Jin-seung Lim Automatic Transmission Design Team
Hello! Cerato (known as Forte in some markets) has released a hatchback model to complete its full lineup along with the Cerato Sedan and Cerato Koup. In this posting, you’ll find more info about the 6-speed automatic transmission that improves Cerato’s fuel efficiency and acceleration.
The Gamma front-wheel drive 6-speed automatic transmission, to be installed in the 2011 Cerato, is a compact transmission of world class standards developed using Kia Motors’ unique layout.
It employs a wide range of new technologies to significantly enhance performance, fuel economy and environment friendliness over the existing 4- or 5-speed transmissions. It boasts superior qualities that put it at the forefront of the world’s automatic transmission market.
Compared to the 4-speed automatic transmission, the 6-speed produces an 8% improvement in fuel efficiency, 15% faster zero to 100kmh acceleration time (seconds) and 17% quicker 60kmh to 100khm passing time (seconds).
The 6-speed transmission also weighs 5kg less than the existing 5-speed, features 62 fewer parts and is 6mm shorter in length. This results in improved fuel efficiency, performance and lighter weight.
About 300 basic patents have been acquired related to the unique layout featuring three planetary gearsets, two clutches and three brakes. In line with our plans to match performance with our design-led vehicles, Kia plans to develop basic technologies for a rear-wheel drive 8-speed transmission and a front-wheel drive 8-speed transmission to secure greater competitiveness in the automatic transmission market.
Additionally, Kia applied a Transmission Control Unit (TCU) with integrated input, control and output units to maintain optimal fuel consumption and performance levels. The input unit receives information related to input/output revolution, oil temperature, number of engine revolutions and engine torque, while the control unit assesses driving conditions and makes calculations to determine the transmission gear and control the oil pressure/damper clutch.
The solenoid valve operates on signals from the control unit and adjusts the oil pressure to control the transmission. In effect, this means that the 6-speed automatic transmission was developed to respond nimbly and accurately to various vehicle data and the driver’s intention, much like a manual transmission.
Meanwhile, the torque converter which relays the engine’s power to the vehicle is more compact and lightweight while offering higher capacity. The seal-type 2-pinion differential provides 50% improved durability while the hydraulic deviation adjustment valve body enhances the shift feel to deliver a smoother ride.
The lubricant grooves of friction materials of the clutch were optimized to enhance oil flow between clutches while shifting gears, thereby enhancing the shift quality. The stacked planetary gear carrier allows for a shorter length and simplified structure. As for the gear ratio, the first gear ratio is set approximately 11% higher than in previous transmissions for improved hill climbing acceleration while the sixth gear is set 2.5% lower to improve fuel economy, raise the top speed and increase durability.
I hope you all have a chance to discover the joyful experience of our new 6-speed transmission with the Cerato.