Example 4

“Hybrid Vehicle”

A hybrid vehicle uses two or more distinct types of power, such as internal combustion engine+electric motor,^[1] e.g. in diesel-electric trains using diesel engines and electricity from overhead lines, and submarines that use diesels when surfaced and batteries when submerged. Other means to store energy include pressurized fluid, in hydraulic hybrids.

Heavy vehicles

Hybrid power trains use diesel-electric or turbo-electric to power railway locomotives, buses, heavy goods vehicles, mobile hydraulic machinery, and ships. A diesel/turbine engine drives an electric generator or hydraulic pump, which powers electric/hydraulic motor(s) – strictly an electric/hydraulic transmission (not a hybrid), unless it can accept power from outside. With large vehicles conversion losses decrease, and the advantages in distributing power through wires or pipes rather than mechanical elements become more prominent, especially when powering multiple drives — e.g. driven wheels or propellers. Until recently most heavy vehicles had little secondary energy storage, e.g. batteries/hydraulic accumulators — excepting non-nuclear submarines, one of the oldest production hybrids, running on diesels while surfaced and batteries when submerged. Both series and parallel setups were used in WW2 submarines.