To replace the existing diesel powertrain with an engine operating on renewable hydrogen with equal performance requirement, requires an engine with a higher boost pressure or larger displacement volume which would lead to violation of the maximum cylinder pressure and engine size. A two-stroke engine operated on hydrogen could generate similar power-density as the conventional diesel engine without suffering from the typical disadvantages of diesel two-stroke engines such as CO2 and e.g., particulate emissions. Obtaining similar power-density in a heavy-duty engine operating on a carbon-free, renewable fuel, compared to diesel fuel without compromising on engine efficiency and emissions. We intend to reach that goal using an innovative solution, operating an engine with a fully variable valve timing system on hydrogen fuel in two-stroke operating mode. A CFD analysis will be performed to investigate the two-stroke engine performance. A full engine full cycle simulation is required to understand the in-cylinder flow phenomenon, turbulence, and combustion for different operating parameters. So, a high-performance computing is needed to perform the CFD simulation. The project is a collaboration effort between Chalmers university of technology (main applicant) and Volvo Group AB. The project will be executed over two years.