In anticipation of a conclusive comparison of different propulsions, the diagrams above compare the delivery maps of various powerplants.
The steam engine has an almost ideal delivery map. An additional map conversion is superfluous here. This explains the significant role played by the steam engine as a drive concept for a long time. Locomotive drives have to fulfill identical requirements as in the case of motor vehicles. Around the turn of century, automobiles were also equipped with steam engines. Electrical drives also indicate a favorable delivery map. The map of a diesel engine, however, seems to be only slightly suitable for motor vehicle applications. The following chapters will deal in detail with necessary torque and speed conversion.