NOVELTY - The system (100) has a cryogenic engine including a first motive power output element. A power generation apparatus includes a second motive power output element. A transmission system receives motive power inputs from the first and second motive power output elements. A transmission output is operably connected for receiving motive power from the transmission system. A controller controls operation of the cryogenic engine and the power generation apparatus. The output elements comprise drive shafts. Driven wheel sets are operably connected to the transmission system.    USE - Parallel hybrid cryogenic engine system for driving or powering a vehicle i.e. bus, from ambient temperature heat generated from waste source e.g. IC engine and fuel cell. Can also be used for a static power unit (all claimed).    ADVANTAGE - The system reduces fuel consumption directly through use of the cryogenic engine to convert wasted heat into shaft power and through use of IC engine running more often. The IC engine does not have to supply entire peak power requirements such that the IC engine can be downsized, thus increasing likelihood of the IC engine operating at an efficient point and reducing capital cost. The cryogenic engine can be used to provide power across a broader range of operating scenarios than an organic rankine cycle, thus providing high yield, and hence providing more significant fuel saving and engine downsizing benefit. The system provides hybridization arrangement to limit the IC engine to a small range of operating conditions in an extreme case, single speed operation, thus providing increased efficiency.    DETAILED DESCRIPTION - The power generation apparatus is an internal combustion (IC) engine.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block diagram of a parallel hybrid cryogenic engine system.    Working fluid storage tank (12)    Heat exchange fluid tank (14)    Cryogenic engine block (16)    Working fluid pump (20)    Working fluid injector (22)    Parallel hybrid cryogenic engine system (100)