Chapter 10: Electric Propulsion

Overview

Almost 60% of the world's oil production is consumed by transportation, essentially all by petrol and diesel engines. Transportation is therefore a particularly important sector of the economy in which to be looking for the introduction of clean, sustainable energy sources. The most obvious approach is to switch to electric propulsion since electricity is the most direct way of utilizing renewable energy.

In this chapter, we describe electric and hybrid versions of passenger and goods vehicles. These fall into the following five broad categories, as distinguished by the source of the electrical power.

1. Vehicles supplied directly by mains electricity; this category includes tramcars and trolleybuses, electric trains, and urban metro systems. All of these, with the exception of trolleybuses, run on tracks.

2. Diesel-electric traction in which a diesel engine drives a generator to supply electricity to a motor; this form of propulsion is employed mostly in large units such as railway locomotives and ships.

3. Battery electric vehicles (BEVs): these are predominantly small, off-road units, although there has been appreciable interest in battery electric cars and vans for urban use. Conventional submarines are also battery-powered when operating submerged.

4. Hybrid electric vehicles (HEVs): these have dual power sources, at least one of which is electric.

5. Fuel-cell vehicles (FCVs): currently, there is great interest among the automotive companies in the use of fuel cells to provide the electricity for motive power.

Electric propulsion has the overwhelming attractions of alleviating the present pollution from internal-combustion-engined vehicles (ICEVs) and of providing silent power for...