Cummins Inc. and Navistar International Corp. recently extended its partnership through the next two emission cycles, with Cummins being selected as Navistar’s preferred supplier of medium-duty and heavy-duty big bore engines for International Trucks and IC Buses in the U.S. and Canada.

Cummins launched the 2021 greenhouse-gas-compliant X15 Efficiency Series engine this past year, making the 15L engine available to International Truck customers.

The Cummins B6.7 and L9 engines will continue to power International MV and HV Series trucks, as well as Navistar’s IC Bus CE and RE Series school buses.

“The extension of our partnership allows both companies to optimize future research and development investments in existing technologies as well as the flexibility to invest in advanced technologies,” said Phil Christman, president of operations at Navistar.