This article first appeared as part of the White Hat Inventions & Innovations Newsletter - 21st October 2008
One hundred years ago, Henry Ford created what is justly regarded as one of the century’s engineering design classics – the Model T. To celebrate the centenary, Ford issued a challenge for students in selected universities across America and the world to design a Model T for the 21st century. In an outstanding achievement, the joint winners were a team from Deakin University in Geelong and a team from Aachen University of Cologne, Germany.
The specifications of the challenge reflected the virtues of the original Model T. The car had to be robust and capable of being produced cheaply (target price of US$7,000) and assembled without access to a large complex factory, thus making it suitable for third world countries. It also needed to be easy and inexpensive to repair. Other requirements included the capability of carrying at least two people, a range of at least 200km and have low emissions.
The Deakin car was dubbed the ‘T2’ (T-Squared). White Hat was invited to attend the launch of the T2 and pester the designers with numbers of technical questions and was particularly impressed with the quality of the team and innovation displayed in all aspects of its design. It’s a pity that the mainstream media didn’t, as far as we could discern, find the project interesting enough to send a representative but, then again, that’s why you subscribe to the White Hat newsletter. So here are some of the aspects of that design.
It is powered by compressed air so the emissions are – air. (Well, not always, but more of that later.) The compressed air powers the wheels using locally designed motors which virtually eliminate internal wear and friction. This remarkable motor and its even more remarkable and delightful inventor is a story in itself so we will tell that story in a future newsletter.
But why motors – surely you only need one motor? Stay with me on this – we’re getting there, but I can see that some of you are getting nervous about that cylinder of compressed air. Won’t that thing blow up if you have a serious prang? (For overseas readers, a ‘prang’ is a form of motor accident that is twice as bad as a ‘bingle’.) Well, we used to think the same about LPG tanks but technology has moved on and they are now regarded as being at least as safe as a petrol tank, which is a comforting thought.
The chassis and bodywork are made from light weight but extremely strong materials thus reducing the energy requirements to move it around. The development of such materials has been a specialty of Deakin University. Light cars can tip easily so this danger was minimised by integrating the compressed air cylinder into the chassis design and keeping the centre of gravity low and forwards.
The T2 has three wheels – two fixed wheels at the front and one capable of turning at the back. “Ha. Nothing innovative about that, it’s been around for yonks. A three-wheeler with the back wheel doing the steering . . ” I hear you say. Well, no; it’s more sophisticated than that, and this is where the two motors come in. There is one directly attached to each of the front wheels. We have all seen the little bobcats on building sites which ‘steer’ by having the fixed wheels on one side travel faster than those on the other side. For most of the time the T2 uses the two independent motors on the fixed front wheels to do the steering using the bobcat principle while the third wheel trails along like the back castors (did you know that the Shepherd's Castors are an Australian invention) on a supermarket trolley. “Great!” I hear you say. “They’ve created a car with all the elegance and handling capabilities of a bobcat mated with a supermarket trolley.” Just hold your fire. The trailing wheel is damped at medium to high speeds so it can’t do the supermarket trolley jitterbug. Then at low speeds the back wheel can be engaged as an active part of the steering allowing for amazing manoeuvrability and ease of parking. In fact the T2 is capable of turning 360° on itself which means that even granny can do a doughnut slowly and safely.
Now to the next concept of the design which the team call ‘drive by wire’. Instead of using mechanical linkages all controls are performed through an electrical bus or sort of local area network. This means that when your clumsy parking means you dint that big Merc you can leave a note on the windscreen saying “sorry, the LAN was down” before taking off at high speed. Did we tell you that the compressed air motors chosen give you maximum power at low revs when you need them? If you are parked in against the kerb there is no use saying “this model develops so many kilowatts in third gear”. You need it now from scratch to mount that kerb and that is what this compressed air motor delivers. But getting back to the electronics. The steering, brake, accelerator and other information is all conveyed electronically to where it is needed rather than through bulky mechanical linkages. This cuts down enormously on weight, moving parts that can go wrong, energy loss through gearbox and transmission, etc. Hence the concept of ‘driving by wire’.
This concept has significant implications for upgradability. As better versions of things become available they can simply be swapped in and out of the ‘wire’. To take an example, consider the situation of a physically handicapped driver. In a conventional car, all sorts of mechanical alterations will have to be made to cater for that disability. In a ‘drive by wire’ system, all that has to be done is to patch in a controller system suited to that driver. In theory you could drive it using an X-Box controller and the ‘fire’ buttons could be connected up to . . but I’m getting ahead of myself; the important thing is that this design makes the T2 much more upgradable and adaptable than conventional design of car which over the years has built obsolescence into its design. The electronics are powered by a battery which uses regenerative braking on the back wheel to keep it charged.
But let’s get back to the sustainability issues. Compressed air was chosen because the infrastructure for ‘refuelling’ is easier to provide than for say, hydrogen powered cars. After all, most service stations provide compressed air for pumping up your tyres. All you need is a bigger compressor and you can ‘refuel’ your zero emissions car in about five minutes. “Aha” I hear you say “It’s all very well . .” O.K, I hear what you say. The car may have zero emissions but if the compressed air (or for that matter, the hydrogen) has been produced by using ‘dirty’ electricity then you are just transferring the carbon emissions out of sight in the same way that Melbourne electric tram travellers can’t see the smokestacks in the Latrobe Valley that are propelling them on their way. Perhaps this concept should be called ‘zeapu’ – zero emissions at point of use. I suppose the principle and only partially satisfactory answer to the charge of greenwashing through zeapu, is that at least the option is open for that compressed air to be produced by solar, wind, tidal or some other form of renewable energy which is something that can’t be said about using fossil fuels. There is nothing to stop you from setting up a personal scuba diving compressor (available off the shelf) in your garage and running that on solar powered electricity - unless of course you come from a place where the sun never shines.
Then for the T2 there was the problem of having the required range of the Challenge which was 200km. One cylinder of compressed air was not capable of achieving this. Never mind. As you remember that Mr Boyle told you in year 10 (or was it Mr Charles?) if you heat the air it will increase its pressure. The air released from a compressed air cylinder is very cold and if it is heated it will increase in pressure and give you ‘more bang for your buck’. Thus the T2 introduced a heater powered by natural gas which stretches one compressed air cylinder to the 200km range. This of course produces some greenhouse emissions but you only have to use the burner and sacrifice your zeapu if you want the extra range.
Finally, there is the issue of whole-of-life carbon footprint. This involves the greenhouse emissions involved in the building, running and eventual disposal or repurposing of the vehicle. The Deakin team has factored these in and tried to minimise them. In particular, the design which allows for continuous upgrades rather than built-in obsolescence prolongs its usable life and therefore reduces its yearly carbon footprint.
Congratulations to all involved with the design of the T2.