hydraulics instead of internal combustion engine

avemt1

i recently heard that ups is designing and testing a hydraulic system to power a torque converter for an efficient delivery system i need to know the validity of the situation and the plausibility of it being run by an electrically powered motor.

brewnog

Haven't heard or seen anything about this. Any more information?

Francis M

I cant remember where I saw the articles but I've heard of this. UPS is essentially looking at experimenting with equipping a small portion of their truck fleet with hydraulics to recapture and store energy used during braking and then use it to assist the ICE during acceleration. I have no idea if they're even past the "still talking about it" stage.

Mech_Engineer

I read about this in Pro-Sci as a next-gen hybrid system, it's not really a "hydraulic" system though, it uses compressed gas. Rather than using a generator and batteries to recapture energy (which is about 35% efficient) a company proposed using a compressor attached to the driveline that pressurizes nitrogen between a "low pressure" tank and a "high pressure" tank during braking. Then, they run the compressor in reverse during acceleration to help the IC engine. The idea is that this system for recapturing energy will be about 70% efficient.

I think I also read that UPS will be doing prototype testing. In the end it isn't a complete ICE replacement, it is a non-electric hybrid system.

LURCH

Unless it's a newer evrsion of this:
http://findarticles.com/p/articles/m..._1/ai_87847732
which is an hydraulic system used to compress a gas.

brewnog

So an accumulator? Sounds like a nice enough idea, packaging is always an issue with such things though.

What did the OP mean about it being powered electrically? Just an electric motor rather than an IC engine?

Francis M

I'm not sure. Now that I've read the OP again it does seem a little confusing.

avemt1

Are you asking about how the system UPS is looking into works or are you asking if it could be used other than with an ICE?
Please, if you could, clarify the original question so the forum can gear the answers more towards what you're expecting for information. Thanks.

Qleap1000

Yes, in the final annalysis of Recovery and Storage of energy there are many (fuzzy) ways of doing it with many ideas. The largest question always seems to be how to store the captured energy and redestribute it in a proper usable fashion.

denni89627

How do they convert the compressed air/gas into momentum? Aim it backwards and use it as a rocket?

Danger

That would be a tad inefficient (and loud!).
The gas would be used to store pressure in the hydraulic system, which can then be used to turn a hydraulic motor (which can be the pump run in reverse).

LURCH

In the first model I ever saw (which was more than 15 years ago) was being test-run in some place like Norway or perhaps Denmark. Thay were putting it in city busses, and it was a very simple mechanism. Gears connected the wheels to a piston that ran the entire length of the bus (underneath), and when hte breaks were applied the wheels pushed the piston into a cylinder that had no vent, compressing the air inside.

When the break was released and the accelerator stepped on, the gearing between the piston and the wheel was reversed, allowing the expanding gasses inside the cylinder to push the wheels in a forward direction.