By Tyler, Geoff
Management Services , Vol. 38, No. 2
The use of electricity to power road vehicles is as old as the internal combustion engine to which it lost out. Apart from the few decades of trolley buses--which my old uncle Alf tells me from experience were lethal things to drive--electric vehicle propulsion went the route of trams and trains plus, comparatively recently, works vehicles like stacker, forklift and tow trucks.
We therefore have two reasons to be interested in what is happening in the development of electric vehicles.
* The works vehicles we use today are those I just mentioned plus personnel carriers used around large complexes and in the leisure and travel industries. Lower running costs, better performance etc will improve the opportunities for efficiency in our use of them.
* The electric motor car will become as much a member of the family as the internal combustion model though may well force changes (for better and worse) in our motoring habits.
Only with the environmental movement has interest once again focussed on electric propulsion. Cynics will argue that rapid development must await the sad day when fossil fuel supplies are so low as to be far too scarce to burn and must be reserved for such things as essential plastics for the medical world.
Being an optimistic sort of chap, I choose to believe that the infant trickle toward finally beating the technical barriers to viable electric propulsion will progress rather that die out because politicians make themselves popular by encouraging it, because companies find publicity of their green development work is good public relations, but above all because motor manufacturers' research has now identified a market ready to buy electric cars once they can get acceptably close to the 'fuel tank' range and speeds of internal combustion cars.
That sentence of Dickensian proportions hinges on the term 'acceptably close' to internal combustion cars. Electric vehicles can do over 100 miles per hour and can have a 200 plus miles range on one battery charge--but not at the same time on the same vehicle.
In the case of works vehicles speed and range limitations would not seem to matter so much. But that is largely because, I submit, we have accepted their shortcomings as a fact of life. If a forklift works a reasonably busy day with an overnight charge we accept it. But how much better to have one forklift which can cope with two or more shifts? What advantages could we obtain from smaller and cheaper power packs? Forklifts need the weight anyway, but light goods and personnel transports would be more economical and faster with less of it.
Some industrial vehicle manufacturers are doing well with the technology available, squeezing performance and design improvements out of that technology wherever possible. Five or six hours' continuous working from fully charged state is now common, for instance.
Surprisingly, the main problems do not lie with the electric motors themselves--in a works vehicle context they are more than capable of the speeds and power asked of them and even electric car manufacturers regard the outstanding challenges as minor. The problems lie in motor control and batteries.
John Lott, general manager of electric vehicle makers John Bradshaw Ltd points out that in a works context, vehicles driven by electric motors actually have an advantage over internal combustion models.
'As work demand on an electric motor increases and the motor slows, horse power and amps increase--in short, the power unit gets stronger as the job gets tougher. Likewise, as the job gets easier, the motor runs laster and amps decrease.'
Werner Harbauer head of Siemens division for electric vehicle drives, has objective views on motor types:
'Rapid acceleration necessitates a motor with high torque, an inverter and control system with high-level current and appropriate control algorithms...and an efficient heat dissipation system. …