Cummins is testing hydrogen injection engines in the USA. The tests include both 6,7 liter and the 15 liter engines. Cummins has a lot of experience with gas engines and the idea is now to have them ready for production in 2025.
Other engine producers like Paccar are also developing H2o combustion engines for the future. The biggest advantage is that these engines can deliver instant power when needed. With a fuel cell electric truck that is not possible without extra battery’s. The biggest question is however which technology is the most efficient in a truck. Both Paccar and Cummins do not comment on that question because that is one of the things that is going to be tested.