Cummins Intros More Efficient Diesels for 2021

Oct. 19, 2020

Cummins Inc. says its 2021-model heavy-truck diesels will deliver greater fuel economy and offer extended oil-drain intervals than current engines. In a virtual press conference on Oct. 13, executives also said mechanical improvements make the diesels quieter at idle and generally more efficient to own and operate.

The economy improvements pertain to Cummins’ X15 Efficiency engines, which are already in production and are getting up to 3.5 percent better fuel economy than previous engines, said Kris Ptasznik, manager for heavy-duty on-highway products. Those with so-called EX ratings can gain an additional 1.5 percent economy. EX engines are paired with Eaton Endurant automated manual transmissions which shift themselves.

Some fleet operators using EX engine-transmission components are reporting mile-per-gallon fuel economy figures in the 8s, 9s and 10s, said RaNae Isaak, power train and cost-of-ownership consultancy leader. Those are achieved when drivers use Smart Coast and other features which let the engine turn in maximum efficiency.

Cummins currently provides an oil-drain interval of up to 75,000 miles for operators achieving 7 or more miles per gallon with the X12 and X15 Efficiency engines. In 2021, customers averaging between 5 and 7 mpg will see their drain intervals with X15 Performance series engine extended by 10,000 miles. New extended-range oil filters allow them to go as long as the oil, so oil and filters can be changed at the same time. Ptasznik said Cummins offers an oil analysis service for customers wanting to establish long but safe intervals.

The 2021 X15 Performance series, which are popular with owner-operators and heavy haulers, will newly offer some powertrain features that were previously unavailable above 500 horsepower, Ptasznik said. Features like SmartCoast, Predictive Cruise Control and Predictive Road Speed Governor will be available for customers with automated manual powertrains in 2021. Many of the powertrain-operating features also work with manual transmissions. Customers can visit the new cloud-based PowerSpec tool via for help with vehicle spec’ing, feature descriptions, and more.

The 2021 engines will be quieter at idle, thanks to a resonator on the X12’s air compressor mount, and certain internal refinements to the X15, Ptasznik explained. Most exhaust aftertreatment equipment is the same, though some slight changes have been made to the X12’s system.

2021-model engines meet reduced oxides of nitrogen limits dictated by the federal Environmental Protection Agency, executives explained. Updated X12 and X15 Performance series engines will go into full production on January 2 and will appear in trucks soon thereafter, while X15 Efficiency engines got the changes early this year.  There will be some minor price increases on the ’21 products as outlined in long-term agreements with truck builders.