Hydrogen engine powertrains are considered as a potentially attractive solution for future life cycle and well-to-wheel CO2 neutral mobility, following a technology open approach and complementary to hydrogen fuel cells. A hybrid powertrain application with hydrogen engines can provide additional functional benefits. Within a joint research project, Aramco Overseas Company, Hyundai Motor Company, Hyundai Motor Europe Technical center, Bosch and Umicore explore the potential of such a hydrogen engine hybrid powertrain for a passenger car application.

The base engine, a Hyundai 1.6 l T-GDI gasoline engine, was modified into a H2 TC DI engine using a hydrogen ECU hard- and software and low pressure hydrogen direct injection from Bosch. In this paper results are presented on the development of a dedicated exhaust gas aftertreatment system and the applied calibration for a lean burn hydrogen engine in a hybrid powertrain in transient operation. Specially designed catalysts and a particulate filter from Umicore as well as a DeNOx system and EGT sensors from Bosch have been specified and implemented. Engine parameters in stationary and transient engine operation were optimized as well as the urea dosing strategy of the dedicated aftertreatment system, pursuing a system approach. In warm transient engine operation such as RDE driving cycles, low engine-out and zero-impact tailpipe emissions are achieved on the engine dyno, affirming the potential of hydrogen engine hybrid powertrains as an attractive solution for CO2 neutral mobility with negligible contribution to ambient emissions in future passenger cars.