This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Developmental Status of Internal Combustion-Hydrostatic Storage Power Systems for City Bus Lines
Technical Paper
785137
Sector:
Language:
German
Abstract
Various regenerative power systems have been hypothesized for
vehicle use; the most promising are the internal combustion
engine-flywheel and the internal combustion-hydrostatic storage
designs. The paper reviews the latter.
Hydrostatic storage encompasses compression of gas~usually
nitrogen~during periods of energy storage, powered either by the
primary combustion circuit or recouped from braking processes. Low
losses provide high conversion efficiency (e.g., 99% for energy
storage) although energy storage per weight ratios are lower than
those of flywheel systems. Automatic controls facilitate regulation
of energy conversion processes; the paper correlates these
processes with different driving operations.
Passenger bus frames are well suited for the system's
spatial requirements. A trial bus completed 4500 km of suburban
operations. Fuel savings amounted to 20%; since fuel costs
represent 5% of a conventional bus's total costs, the
additional equipment costs were not offset. Increase of energy
storage concentration values is considered crucial for economic
feasibility