Electricity generating Shock absorbers

[JanGeo]

MIT has come up with an energy conserving device for vehicles. They have turned the shock absorber into a hydralic pump to power a turbine and use it to generate electricity to power the electrical system of the vehicle instead of the alternator. Seems about 1000 watts is available on the typical SUV size vehicle just from the bumps in the road. Big trucks would generate more power to drive cooling systems etc.

The idea is not new . . . 6/13/06
http://tech.groups.yahoo.com/group/ETList/message/6195

[bobc455]

Pretty clever. Otherwise the energy just goes toward making the shock absorber hot, might as well recover the energy as electricity.

-BC

[slurp812]

That is so cool. We need more tings like this in all cars, like solar panel roofs, etc.

[GasSavers_TomO]

When I first read the title I had thought that the shock absorbers were using static electricity to create the charge, lol.

Good idea. Perhaps combining this system with the thermal-electric converters in the exhaust would be a great step towards removing the alternator from the automobile.



Someday they will make an electric powered alternator to go a long with the electric power steering, A/C, and water pumps...











Ok, sorry, j/k about the electric driven alternator.

[dkjones96]

I have a problem with all electric accessories. The more efficient way to run the accessories is directly off the crank. This does, however, lead to inefficiencies as they are run all the time regardless of being needed or not. I would like to see accessories run off the belt but, instead of traditional pulleys, using electromagnetic torque converters like the Prius uses in its 'cvt'. If permanent magnets are used, any time the accessory is in use it's also acting as a generator. You apply more load to it to bring the accessory up to speed and as engine rpm changes the ac compressor or power steering pump can be run at a constant speed by varying the 'clutch'.

I've actually wanted to build one of these to replace the thermostatic clutch on the Durango and use it with a variable speed electric fan controller.

The only problem I can see with the shock absorber generators is that it can't replace an alternator in the majority of those large vehicles. Anything used as a work truck will, in general, be subjected to long durations of idle. Heck, even my cars get that, especially at night when I need light and power from the car to work on something.

[theholycow]

Hmm....what about using shock absorber energy to feed hydraulic power into Gary's hydraulic hybrid pressure storage? That should be cheap and easy, probably using off-the-shelf hydraulic rams in place of shock absorbers...

[trollbait]

The more efficient way to run the accessories is directly off the crank.

Considering the loss of energy conversion of the alternator on a traditional car, this is true. But when you start generating electric with other sources, like these shocks or regenerative brakes, then it becomes possible to improve fuel economy by removing their parasitic load. Volvo, and I believe BMW, are doing this with their eco trims.

Plus, electric accessories are more flexible. They can be placed anywhere with regards to the drive train, and they allow continued functionality with auto-start systems.

[R.I.D.E.]

Yes HC it would add efficiency. My system is properly understood when you consider that no matter what you think the primary source of propulsion will be in the future (electric, hydrogen, diesel, gasoline etc), the hydraulic accumulator and in wheel regenerative drives will be the best means of applying energy to the vehicle. Another consideration with shock absorber created energy is you have no need for the electrical conversion.

Imagine what that kind of shock absorber would cost!!!!!!!!

No electric hybrid will ever approach the efficiency my design will produce, once the pump efficiency has been verified. Current design are at 78 %, easily twice any hybrid electric electric vehicle. I am hoping my design will raise this to 80-85%. Thats regeneration efficiency, which means you have to go from wheel to accumulator, then back to wheel.

Depending on RPM the best available bent axis pump-motors peak at 93%, at higher displacements. They suck at low displacements. The best accumulators are 99%. At low speeds I would like to see 95+% on my design. High speeds will not be necessary since wheel speeds should never exceed 1000 RPM. The competition bent axis pump drops off to about 75% at 3000 rpm which kills your highway mileage.

We all know you double the engines efficiency when you operate it only in its sweet spot on the BSFC map. Storage of only max efficiency engine operation can double mileage, just like the best hypermilers can achieve, but it would be even better because although you are pulsing the engine, the vehicle speed remains constant (eliminating the exponentially higher total drag at the peak of your pulse). This is accomplished by constantly increasing the wheel-motor displacement as accumulator pressure decreases. You have the ability to apply the exact same amount of power regardless of accumulator pressure (less displacement at higher pressure, more at lower pressure-infinitely variable and controllable).

The argument about the weight of the accumulator itself is also fallacious. If we spent a millionth of the money we have on battery technology, we could easily make accumulators that would have maximum pressures of 12000 PSI, almost 3 times the operating pressure of typical current designs. This requires no new technology. America's Cup Racers already use 12k PSI accumulators, the only drawback is the cost. The UPS trucks work on under 5K PSI, need 82 gallons of hydraulic fluid, but they weigh about 13 tons.

In a 1 ton car that would mean you would need only 1/13 of 82 gallons. If you double the pressure, you only need 1/26th of the fluid, or about 3 gallons. You would save that same weight with your less than 4 gallon fuel tank, at least within 20 pounds.

regards
gary

[dkjones96]

You have to be really careful about a lot of movement in the suspension system. If you start letting the wheels move a lot because you need the power you'll end up with very bad handling and lots of worn out suspension parts.

Gary, if you're wanting to build that system into a vehicle for testing I'd recommend a 4x4 SUV with manual hubs(or none at all like the durango). That'll make building a working prototype a heck of a lot easier and faster than in a car. Maybe a little Suzuki Samurai or something.

[theholycow]

Originally Posted by R.I.D.E.

Imagine what that kind of shock absorber would cost!!!!!!!!

As I envisioned it, it should cost the same as average decent shock absorbers. It would be simpler than them, instead of having a gas chamber and valves, it would have a hydraulic hose coming out the top or side. It wouldn't be as complex or expensive as a modern hydraulic shock absorber used to lift a vehicle on-demand (but, come to think of it, could do that job too).

As you go over a bump, the bump pushes the piston into the cylinder, forcing hydraulic pressure into the lines, the opposite of how a common hydraulic ram is used in a jack or snowplow or backhoe. The energy is received at the accumulator. I don't know how the accumulator works, so maybe it would get complicated trying to receive the energy without making a harsh ride.