Hydrogen fuelled hybrid powertrain and vehicle

A powertrain, comprising:

• a primary power generating system for generating a primary drive torque, the primary power system having a hydrogen-fuelled internal combustion engine operating with a lean hydrogen gas fuel mixture, the internal combustion engine having at least one air charge boosting device for increasing the primary drive torque;
• a secondary power generating system having at least one electric torque generating device for generating a secondary drive torque, the secondary power generating system being constructed and arranged such that the secondary drive torque complements the boosted primary drive torque;
• and
• a control system including at least one control module and configured to:
• control the at least one air charge boosting device to increase the primary drive torque over a first range of powertrain operating speeds, and
• control the secondary power generating system to boost primary drive torque over a second range of powertrain operating speeds at least a portion of which is lower than the first range of powertrain operating speeds.