Holden powers up for the future

HOLDEN has moved to capture the environmental high ground from Toyota and has wrong-footed Ford Australia by strengthening its research links with the CSIRO to develop electric power management systems for future cars.

While Toyota has successfully marketed the petrol-electric hybrid Prius in Australia, the Holden initiative lays the groundwork for electric cars of the future, whether they are hybrids or fuel cell vehicles.

The work is the next step on Holden’s path towards building production hybrid Commodores and then eventually production fuel cell-powered Commodores and all-wheel drives for Australia.

The agreement with the CSIRO revolves around a further development of supercapacitors (see below for more detail).

Both organisations believe the research will result in supercapacitors being three times more effective in delivering power to the wheels than current supercapacitors.

This is important for future cars because it means conventional rates of acceleration will be available for the electric motors that will be powering tomorrow’s vehicles.

The research paves the way for the introduction of a Holden hybrid at a time when Ford Australia is saying that it does not plan to introduce – in the short term at least – a hybrid Escape 4WD despite that vehicle already being in production for the US market.

Holden and the CSIRO first worked together on the ECOmmodore in 2000, a hybrid Commodore powered by a Family II four-cylinder engine and an electric motor.

The key to the ECOmmodore was the supercapacitor, which gave a surge of power to the electric motor to provide the equivalent acceleration of the Holden 3.8-litre V6 engine either from standstill or for overtaking.

Both Holden and the CSIRO believe additional research funded by General Motors can create a key power platform for either petrol-electric hybrids or fuel cell power sources.

It also means that Holden is not trying to pick a winner in the emerging move to electric propulsion because any developments in supercapacitor technology can be used no matter what form of electric propulsion wins out in the end.

Holden has been given this responsibility by GM because of the nature of our market.

Holden chief engineer Dr Laurie Sparke said Australians, more than in most other parts of the world, required cars with a capacity for relaxed long-distance cruising and powertrains with strong performance for towing and hill climbing.

This places special demands on electric powertrain systems that the supercapacitor overcomes.

This is especially important for the future of the Australian car industry in an electric-powered world.

Dr Sparke said Australia’s car industry was built around the manufacture of large vehicles.

The market is dominated by large cars and is moving to 4WD wagons.

"A significant consumer move away from large cars would place enormous pressure on the local manufacturing industry and the myriad industries that rely on automotive production," he said.

"One thing is certain: electric propulsion is the road ahead. It is only the fuel used to power these electric engines that is in question."

Supercapacitors explained

THE problem with batteries is that, while they can deliver plenty of energy for a long time, they take time to charge and discharge.

This creates a bottleneck in the amount of power available for sudden acceleration.

A similar bottleneck is created when they are being recharged (under regenerative braking, for example).

The reason for the sluggishness is because batteries are charged by a chemical reaction within the battery when power is applied at the terminals.

Discharge is simply the reverse of that chemical reaction producing the electric energy at the terminal.

But the chemical reaction for charging and discharging takes time.

It also places high demands on the battery that shorten its life.

This was one of the reasons the conventional electric car using banks of conventional batteries was a dead duck – its battery packs were going to need to be replaced every 30,000km at huge expense.

A capacitor has no such problem because the energy is stored by electrons sitting on the surface of material inside the device.

These electrons are pretty much available instantly and can be replaced almost instantly when charging as well.

This is ideal for high output for acceleration and for strong capacity to recharge under regenerative braking.

But capacitors have a limited amount of surface area to store the electrons so they do not hold much energy.

Their surge of power can be spent within 90 seconds.

With supercapacitors as being developed by the CSIRO and Holden (as pictured here), however, engineers have figured out how to put a high concentration of electrons on the internal surfaces.

This gives the best of both worlds in terms of power delivery and storage.

What is even more appealing is that, unlike batteries, they can be charged and discharged indefinitely, require no maintenance, last the life of the vehicle and are made from non-toxic, relatively inexpensive materials like carbon.

It also overcomes one of the dichotomies of electric cars. The more power you wanted, the more batteries you needed. The more batteries you put in, the more power you needed to drive around. You get the picture.

Using a combination of supercapacitors and batteries, the power pack can be reduced from 500kg (about half the weight of a car) to 200kg.

That is why GM, through Holden and the CSIRO, is pursuing them for future cars.