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Publishers Letter

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 electric vehicle?

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 load.

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.

Leo Simpson

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