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An Eaton Cummins Endurant automated transmission and GPS-enabled predictive features are required for EX ratings, which the 2021 X12 offers thanks to a new ECM. (Cummins)

Cummins unveils EPA-compliant 2021 heavy-duty diesels

The X12 and X15 Performance Series follow the already-launched X15 Efficiency Series to offer a range of efficiency-boosting predictive technologies.

Cummins reserved its first virtual press event since the pandemic onset to reveal details of its EPA 2021 emissions-compliant X12 and X15 Performance Series engines. Built upon the architecture of their EPA 2017 predecessors, the diesel power units follow to market the 2021-compliant X15 Efficiency Series that was launched earlier in 2020 and has demonstrated up to 3.5% better fuel economy (FE) compared to the 2019 engine. “When you look at the engines, you might notice some slight external modifications, but the bulk of what’s changed was internal components,” said Kris Ptasznik, Heavy-Duty On-Highway Product Manager at Cummins, during a virtual walkaround of the new engines.

In 2021, the X15 Efficiency with EX ratings (which requires an Eaton Cummins Endurant HD automated transmission and GPS-enabled predictive features) could see an additional 1.5% FE improvement. Class 8 truck customers requiring more than 500 hp (373 kW) and selecting the X15 Performance Series, which ranges from 525 to 605 hp (392 to 451 kW), can receive FE gains up to 2% compared to the EPA 2017 version. Features previously unavailable above 500 hp – SmartCoast, Predictive Cruise Control and Predictive Road Speed Governor – will be available for 2021 X15 Performance engines with an automated manual.

Suitable for regional haul, vocational and intermodal truck applications, the 350- to 500-hp (261- to 373-kW) X12 will offer an up to 2.5% potential FE gain in the base engine and possibly 4% overall with the EX rating. Limited-production build for both engines had already begun in mid-October, and full production is set to begin at Cummins’ Jamestown Engine Plant in New York on January 1, 2021. Ptasznik provided technical details and fielded questions from editor Ryan Gehm and other journalists during the launch event.

What are the main improvements to X12?
We were able to identify some components through long-hour and high-abuse testing where material modifications reduce the likelihood of a failure. The primary one is the camshaft material changed to a different alloy of steel – that actually was a 2021 product change that was adopted early in the current product. The X12 [is] lightweight at just 2,050 lb (930 kg) – these changes did not add any weight to the product.

We’ve also improved engine breathing, increased compression ratio and reduced frictional losses through modified ring packs to improve overall efficiency. The EX ratings will be available to customers with the 2021 X12 thanks to our new electronic control module (ECM). Also available in 2021 is the Cummins connectivity module called Acumen. It offers customers another path to Cummins’ connectivity features and can provide the ‘look-ahead data’ needed for the EX ratings. And we’ve created the option to reduce engine noise in operation and at idle through an air compressor resonator, which the X15 typically has had.

How about for the X15 Performance Series?
The X15 is a global platform. While not all product updates are needed for North America, design enhancements like a larger thrust bearing required for overseas operation will enhance product durability for all global customers including North American on-highway. We also updated some of the air handling characteristics for the engine, including leveraging EGR [exhaust gas recirculation] flow for engine brake assistance.

We improved the air handling system for better compression ignition and engine efficiency. At the same time, we focused on reducing parasitic and frictional losses by improving the power cylinder, reducing the water pump speed and resizing some critical components. For driver comfort, we reduced engine noise at idle [by 3 dB] and made enhancements to engine shutdown. It’s quieter through improved geartrain finishes and profile designs. Like the X12, the X15 comes with a new ECM and the available Acumen module.

Can you provide more details on the Acumen module?
Acumen is a secondary connectivity module that we’ve released, [essentially] a cellular connection to our engine. It’s not a part of the ECM; it’s remote mounted. It’ll be in the Freightliner Cascadia underneath their dash and we’ll have a proprietary data link going through the firewall directly into our module so that we can connect to our engine wirelessly.

It truly is a data logger that’s in there and we can collect a lot of data, [much] of it for future reliability – How can we be agile if something does happen? How do we make it better? To collect data on emerging issues as fast as possible and fix it as fast as possible. We also have our suite of connected features that typically come through a service provider like Connected Diagnostics, Connected Adviser, and over-the-air calibration updates. [Acumen is not intended to be a replacement for the telematics service provider’s device on the truck, Cummins noted, and the customer must consent before the data can be collected and sent regardless of whose device it is.]

Any insights from fleets on the X15 Efficiency since it’s been out for a while?
Feedback’s been positive. On-Ramp Boost, Predictive Engine Braking, Predictive Gear Shifting, they all make the driver’s job easier. Some of the OEMs are selling nearly 50% of their Efficiency hardware with these features default-spec from the factory. That speaks volumes. There are some additional features coming geared more towards fuel economy that are being released over the next several years, and I’ll leave you on a teaser note with those.

Can you explain the differences between the Efficiency and Performance hardware?
It’s essentially a completely different engine. Turbo size to support greater airflow needed to create the additional horsepower the Performance hardware offers. Pistons, piston cooling nozzles, oil cooler elements, EGR cooler, and cylinder head – all different. Essentially other than the crank and block, consider it a different engine. There’s a lot of parts there to accommodate that increased power demand – not just for how do we make more power, but how do we make more power reliably and still be compliant from an EPA standard? It’s really difficult for somebody to re-rate a 500-hp to a 525-hp, just in the amount of hardware that’s needed. So, everything 500 hp and below (Efficiency) shares a common hardware set, and everything above 500 hp (Performance) shares a common hardware set.

How many of these enhancements translate to an engine with a manual transmission?
Several of the features that are coming out, we don’t have control over the transmission, so they don’t work. Predictive Gear Shifting, for example. We try to make things as compatible as we can across the board with both manual and automatic transmissions, as we have the communication to get there. Things like Predictive Cruise Control work regardless of the transmission. Predictive Engine Braking does command a downshift, so that requires a transmission that we can command to get that to work. So, it just depends, but obviously we want to deliver the most value to as many customers as possible, so we try not to limit unless it’s a hardware limitation.

Any adjustments to the aftertreatment systems?
By and large they’re very similar products. The only big [adjustment] that comes to mind is the DEF mixer for the X12, and that’s just having multiple suppliers to make sure we can keep up with production demands. Performance in a test cell though, they’re fairly identical, so it should be a transparent change.

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