Hydraulic Hybrid Cars: No Batteries Required

Design News ^ | April 28, 2008 | Joseph Ogando

[saganite]

This article is a little dated but informative about where hybrid technology is headed and it's not electric. I've been following this for a while and rumors that Ford was going to announce a hydraulic hybrid F-150 truck this year seem to be delayed. However, in a few years we might get a chance to buy one. Double the city driving mileage without the complication of batteries!

[ken21]

if it’s viable, i have no idea,

ford needs to get moving.

[saganite]

Read the entire article. It’s more than viable, they’re ironing out the engineering kinks now.

[xcamel]

two problems:
accumulators don’t work well below 20F
accumulators can explode with enough force to rip a car to pieces.

[oneolcop]

Let’s do it!

[weezel]

Farm equipment, combines for certain, have hydraulic motors propelling them. They have forever.

[DoughtyOne]

It seems to me that carrying around that much water at in excess of 3,000 pounds PSI, would weigh a considerable amount. It would also seem that this water would be waste water upon release from the pressure tank. If it wasn’t, there would have to be a fairly significant capture tank. If the water were turned to waste, it would amount to quite a sum of wasted water if all vehicles were using this system.

Perhaps I’m not quite understanding the process fully, but these problems would seem to preclude water being used as the driving force this article seems to promote.

[Right Wing Assault]

500 kW/kg

How does that work? 500 kW is almost 700 hp. Per kg?

[Moonman62]

However, in a few years we might get a chance to buy one. Double the city driving mileage without the complication of batteries!

And replace it with the complication of hydraulics. I bet there's a reason why this old technology isn't already on the market.

[bvw]

What kind of accumulators are you talking about?

200 Bar is not super high pressure. Should be able to wind a tank with kevlar strands piano-wire style and an outer blast absorbtion layer and still keep the tank light weight. Jetting, or rocketing of the tank or hoses at that pressure is another consideration.

[InABunkerUnderSF]

Ever seen what happens when a 3000 psi air tank explodes?

Me neither but scuba tanks occasionally explode at considerably lower pressures. Here is a photo of the inside of a scuba fill station after an explosion. The red stuff being blotted up by the insulation is the operator's blood.

If we're going to go tooling around with 3000 psi pressurized tanks in our cars we should consider lowering speed limits considerably.

[mountainlion]

I would rather drive a 59 GMC truck.

[bvw]

Not water, hydraulic fluid and a gas separated by a rubber-type bladder. The gas is usually nitrogen, but it could be something else. The fluid could be a petroleum based oil, or it could be a water-oil mixture, or some exotic fluid.

[InABunkerUnderSF]

Farm equipment, combines for certain, have hydraulic motors propelling them

Yes but the hydraulic motors on farm equipment are driven by diesel or gasoline engines, not compressed air. Hydraulic fluid is generally safe but compressed air can be very dangerous.

[kidd]

I’ve always wondered why this wasn’t being done. This would be especially useful in city driving (frequent stop/start cycles).

Use the energy wasted by braking to get the car moving again. Extends the life of the brake pads as well.

[saganite]

Gasoline can explode with enough force to rip a car to pieces and to my knowledge hydraulic accumulators have been functioning in aircraft for decades.

[Old Professer]

bump

[xcamel]

They aren't real tanks - they are cylinders - like large (in some cases) hydraulic pistons with a collector tank. They can operate up to 15,000 PSI. The most common application is "ride control" devices for backhoes to smooth out the "hobby horse" effect when driving down a road.

[DoughtyOne]

Looks like I’m going to have to study up more on this one. Thanks for the mention.

[saganite]

I read the entire article and didn’t see a mention of water but maybe I missed it. To my knowledge they are compressing a gas, nitrogen I think but could be wrong, and that is how the energy is stored. The fluid (if that’s what you’re referring to) is hydraulic fluid, not water.