Hydrogen has recently become a primary focus as a future carbon-free fuel for transportation, especially for heavy duty commercial vehicles. The hydrogen internal combustion engine (H2 ICE) shows promise, as current manufacturing facilities and vehicle architectures can be largely maintained while keeping the initial purchase price of the vehicle relatively low. However, hydrogen combustion engines have challenges to overcome. One of the main challenges is to provide transient response on par with current diesel engines while maintaining low NOx emissions from the engine.
Previously, simulations were performed by AVL List GmbH and SuperTurbo Technologies of a mechanically driven turbocharger, the SuperTurbo, on a 13L H2 ICE. This paper covers follow on work of actual engine testing of the H2 ICE with the SuperTurbo in an effort to reproduce the simulation results with engine test data. The primary focus of the engine testing was to demonstrate low engine out NOx emissions through transient operation comparable to current diesel engines, as well as demonstrating engine out NOx emissions below 0.4 g/kWh on the WHTC transient cycle. These goals were achieved in testing, and additionally similar low NOx emissions were demonstrated on the NRTC and FTP transient cycles. Following the engine testing, modifications to the model were made to better match the engine data, matching the IMEP and fuel efficiency through the cycles more accurately. Additional simulations were performed to estimate future improvements that could be made to the H2 ICE engine system utilizing the SuperTurbo boosting system.