Points of Interest | Green Energy News

March 28, 2004 – Vol.9 No.1

POINTS OF INTEREST.

A weekly collection of websites worth visiting.

There’s more than one way to build a hybrid vehicle. There’s the kind already available, a conventionally-powered vehicle with an Electric assist motor energized with a Battery.

Then there’s the other kind, not yet commercially available, a conventionally-powered vehicle with an assist motor energized with an Energy Storage Device.

See the difference? Removal of the word Electric opens up a wide, new, range of technological possibilities, as does the term Energy Storage Device in place of the word Battery.

Two companies, Permo-Drive of Australia and Torvec of the U.S. make variations on hydraulic hybrid vehicle systems.

Though there are certainly proprietary differences in the technologies, both capture the energy of braking to pump hydraulic fluid into a device known as an accumulator, which is really an Energy Storage Device. Internally an accumulator has a bladder, diaphragm, or piston that puts pressure on the hydraulic fluid inside. (The fluid itself can’t be compressed, of course.)

When needed, such as for acceleration or hill climbing, a valve opens and hydraulic fluid forced out under pressure to power a hydraulic motor which, in turn, assists the conventional internal combustion engine to propel the vehicle.

The advantage, besides improved fuel economy and less wear and tear on brakes, is that the lost energy of braking is captured easily. In a hybrid electric vehicle, such as those now available, recapturing energy involves recharging a battery pack, always a slow, inefficient, procedure.

The technology being developed by Permo-Drive is for truck applications. Torvec’s main focus seems to be developing an all terrain vehicle drive system it dubs Fast Tracked Vehicle. The hydraulic hybrid drive is barely mentioned on the company’s website.

Another company, Maxwell Technologies, a maker of ultracapacitors, would like to see its technologies used in place of batteries in hybrid vehicles. The use of ultracapacitors has the same advantage as hydraulic accumulators: The energy of braking is captured almost immediately, no waiting for a battery to recharge. Maxwell’s technologies, like Torvec and Permo-Drive would be more efficient at energy capture, in other words.

The disadvantage of ultracapacitors may be cost, but the company seems to working on that. Maxwell has just introduced an ultracapacitor with the same dimensions as a D-cell. As food for thought, the battery pack in Honda’s hybrids is comprised of dozens of D-cells. We’ll see if Honda attempts to replace its nickel metal hydride batteries with Maxwell’s D-cell-sized ultracapacitors - at least for an experiment - for even better fuel economy.

Visit Torvec at http:www.torvec.com/ , Permo-Drive at http://www.permo-drive.com/ and Maxwell at http://www.maxwell.com/