One of the most important aspects of the new Kenworth K220 will be its driveline and whether it retains enough of that traditional Cummins/Eaton secret sauce, which has made the model so popular. There is something about the feel of driving a Kenworth which shouldn’t be changed, too much.
The vital ingredients are there. The drive line consists of a Cummins engine and an Eaton transmission. Although there are now two alternatives on both counts, two types of engine and two types of gearbox.
The combination of Kenworth, Cummins and Eaton has changed with the increasing integration of systems between the three, making the new combination much more like the integrated proprietary driveline offered by the brand’s main rivals.
The Cummins X15 and Eaton AMT have a common electronic platform, ADEPT, which also communicates, and is integrated, with the new Kenworth electronic architecture. The set up in the K220 is a culmination of a series of innovations which we have seen in recent models.
The new X 15 is a major step forward for the Cummins brand. There are now two alternative engines included. Truck buyers have a choice between the Efficiency Series and the Performance Series.
This gives Cummins the opportunity to keep more traditional, performance oriented truck buyers happy, but also offer something to the fleets which have become much more fuel economy oriented in the past few years.
These engines do not use EGR at all, but instead have a single module after-treatment system, which includes the SCR unit and a DPF, with improved servicing intervals. The ADEPT electronic engine control is said to be capable of a six per cent improvement in fuel economy, over the current product.
The Efficiency Series of this engine is available from 550 to 580 hp (410-432kW), while developing 2800Nm (2050 ft lb) of torque. These engines also include something called Hill Climb Assist, which uses an inclinometer to detect when the truck is heading up a grade and changes the shifting strategy on the AMT to suit the conditions and maximise the power available.
Meanwhile, the Performance Series is much more like the traditional X15 with power outputs from 525hp to 625hp (391-466kW) and with torque ratings from 2508 to 2779Nm (1850-2050 ft lb).
The big difference between the two is the fact that the Efficiency model is only available with the Eaton Endurant XD Pro AMT and the engine performance characteristics have been designed to integrate precisely with the control systems on the transmission, with the aim of minimising fuel burn.
The arrival of the 18-speed Endurant XD Pro is a timely one for Kenworth. The advance of AMTs fitted in the brand’s competitors have meant the Eaton Ultrashift used in the K200 could never match its rivals in terms of speed of changes and smoothness of operation.
For Eaton this new transmission is a game changer, on the evidence of a relatively brief test drive. The performance of the transmission is a match for its finely tuned European competitors. The AMT is responsive and intuitive, a performance which means the driver doesn’t have to think about which gear is needed, and when.
This kind of performance from an AMT is likely to push the percentage of Kenworths coming out of the Bayswater plant fitted with an AMT well over 40 per cent, compared to the low thirties it is today. The Endurant XD Pro does have the capability to go right up to the highest GCM rating, but will be rated up to 97 tonnes for now with higher masses being allowed when the brand has more experience with the product.
