Cars you won't be driving to the gym

Forget about converting food crops to ethanol to power future cars; here's a way of directly converting energy stored in the food you eat to kinetic energy.

We're not talking anything as crude as Fred Flintstone's mechanical tutu, powered by legs poking out the bottom. These are more like those mail-order dynamo-powered torches and radios.

In California, the principle has appeared in the form of the HumanCar Imagine PS Bionic E-Hybrid. Each of these elements warrants a brief explanation, because combined, they give a very good picture of the vehicle as a whole, helping to explain why it looks like an extended bobsleigh on four skinny wheels with four push-mower handles poking out the top.

E-Hybrid refers to the fact that it's not just a human-powered car but a plug-in hybrid (PHEV) with a difference. The battery pack gains most of charge from connection to a domestic power socket.

Bionic alludes to its primary difference from other PHEVs, like GM's Volt or Fisker's Karma. Instead of an internal combustion engine, it uses the human body as a source of supplemental power. Each passenger sits in a kind of rowing machine connected to a dynamo which helps charge the battery. But because of the plug-in facility and because each one seat works individually, passengers are not roped into a compulsory exercise regime. Grandpa and the baby are welcome to come for the ride.

PS stands for Power Station -- so-called for its 110V vehicle-to-grid capacities. That is, its battery is capable of feeding excess energy back into the power grid. This makes it very state-of-the-art indeed.

The car is capable of up to 100 km/h, but is governed to 40 km/h to keep it street legal in compliance with the low-speed neighbourhood electric vehicle (NEV) status it's been granted by the US Department of Transportation.

Another novelty is its lack of any kind of tiller. The Imagine's chassis is engineered for lean-in steering, like a skateboard.

The Concept goes back to 1968, to the day Silicon Valley engineer Charles Greenwood was sitting in a traffic jam full of overweight drivers inhaling toxic exhaust gases and getting no exercise. In response, he has spent the ensuing 40 years working through a series of prototypes designed to solve both problems simultaneously. The Imagine is but the latest incarnation.

The Imagine deploys a fair whack of computing power to help maximise its operating and charging efficiency and passenger fitness. Power up, cruise control and energy regeneration systems function on demand through the use of keys on the central brake lever. You can option it up with touch screen GPS and biometric data system, iPod audio, Bluetooth and a foldaway soft-top.

Meanwhile, half a globe away, Hungarian company Antro has rolled out a different take on the theme. It has unveiled a prototype of its three-seat Solo, a solar/human/petrol-electric hybrid prototype (pictured here in blue) built partly around the same principle as the HumanCar -- getting some exercise if you want, while going places.

The Solo uses a light magnesium alloy frame with carbon fibre panels, keeping its weight below 350 kg. Helped by a super-aerodynamic exterior with a drag coefficient of just .022 Cd, the result is a claimed top speed of around 140 km/h and a range of up to 960 km with fuel economy of around 2L/100km.

The Solo uses 2.3 square metres of solar roof-mounted solar panels to help keep the battery topped up. Using a 20 kW electric hub motor on each wheel, in pure electric mode it's short-haul only, good for trips of 15 to 25 km.

Regenerative braking is supplemented by regenerative suspension, using kinetic energy created in the shock absorbers on bumpy surfaces to recharge the battery. To supplement the solar and regenerative sources, there's a set of pedals on each seat connected to a generator. For when the driver is alone, passengers aren't up for the exercise and to extend the car's range, Antro is working on a 15 kW IC engine calibrated to run on petrol, vegetable oil or ethanol.

Antro claims CO2 emissions will be between 45 and 63g/km -- around half the cleanest cars currently running on Australian roads. When burning vegetable oil, alcohol, or synthetic, renewable fuels, the amount of carbon dioxide released is equal to the amount the plant already absorbed during its growth as part of the agri-energetic cycle.

Another unique facet of the car lies in its modular design -- the ability to hitch two Solos together to make a six-seat Duo. Details here are a little light-on at present, but it's an idea bound to appeal for both fuel efficiency and in keeping its space demands down in congested city traffic.

Expect more soon -- the company is aiming to put it on European roads sometime in 2012 at a hoped-for price of about $20,000.

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