Electric vehicles might be a technological dead-end
This month we have two reports on electric vehicles. The first,
on the General Motors’ Chevy Volt, is about a state-of-the-art electric vehicle
which is slated to go into production in two years’ time. The second, our report
on the AEVA field day at Rouse Hill in Sydney during October, shows developments
at the do-it-yourself end of the electric vehicle scene.
Neither report really gives many clues as to what sorts of cars
we will be driving in 10 years’ time or further into the future. For a start,
the majority of the cars we are driving right now will probably still be on the
road in 10 years’ time. Second, it is by no means certain that the prototype
electric cars presently being touted by the major car manufacturers will go into
production in their present form. In fact, it is by no means certain that
General Motors in the USA will even survive their current financial woes without
substantial government assistance and restructuring.
In any case, if it does ahead, it appears as though the motor
and batteries finally employed in the Chevy Volt could be quite different to the
concept car seen at the Sydney Motor show. We have also stated in a past issue
that we thought the Chevy Volt was a "pretend electric car" in that it has
fairly limited battery capacity and a small internal combustion engine to
provide long range trip capacity. Given that GM has prior experience in
producing the ill-fated EV-1, you would think they would take a better approach.
Or is it because car dealers can see that electric cars will require little
after-sales service and there won’t be much money to be made from a pure
What does seem certain is that more hybrid electric cars will
be available in years to come. Toyota’s Prius and the Lexus hybrid range of cars
have already been a big sales success and you can expect more of the same from
Toyota, Honda and the other Japanese manufacturers. There is even a Commodore
hybrid planned for release in a year or so.
However, it must be said that none of the existing hybrids from
Toyota or Honda really push the envelope in getting the really high fuel economy
which is potentially available. Already, the Toyota Prius has been modified by
DIY enthusiasts to get claimed economy down below 2.5l/100km. How much better
could it be if Toyota pushed the technology as far as it could? The good news is
that diesel hybrids being developed by some of the European car manufacturers
(eg, the VW TwinDrive) are planned to do much better and will have an electric
only range of 50km or more, comparable with the Chevy Volt.
But just because hybrid electric vehicles may seem more
practical at the moment, this does not mean that particular technology will
necessarily dominate in the long term. Other hybrid vehicles could take the
spot-light. What do I mean by that? At present there is quite a lot of research
into diesel hybrid vehicles with hydrostatic transmissions – no electric motors
would be involved. If that seems outlandish, consider that the vast majority of
earth-moving vehicles, from the humble Bobcat right up to huge mining machines,
use hydrostatic transmissions. They run at very high hydraulic pressures
(typically 21,000kPa or 3000 psi) and they use a hydraulic accumulator which is
driven by a relatively small diesel engine working at more or less constant
Furthermore, a vehicle with a hydrostatic transmission can
provide very effective regenerative braking – much more effective than electric
motor regeneration. Another big advantage of a diesel hydrostatic vehicle is
that it does not have a large investment in batteries which have long-term
consequences for the environment. In reality, such vehicles would not represent
a drastic change from technology available right now.
So what sort of vehicle are you likely to be driving in 10 or
15 years’ time? It might be a diesel hydrostatic.