EV Power Generation, Beyond Regenerative Braking

"davesaddiction @ opposite-lock.com" (davesaddiction) 09/08/2020 at 12:15 • Filed to: None

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Came across this interesting article on The Drive about a Mercedes system that produces electricity over rough roads. Made me think about what other energy could be harvested. Solar’s a bust - not enough surface area, but wind seems like it could make sense for drivers with a decently long commute on the highway. Now, of course, you’d be adding drag and therefore losing efficiency, but would the power you’d produce make up for the losses (and enough to make it worth it)?

!!! UNKNOWN CONTENT TYPE !!!

In order to investigate energy-saving efficiency, a wind turbine of 400w was mounted to the front bumper of vehicle. In the experiment, there are two choices of charge types for vehicle. An electromagnetic clutch was designed for cutting charge system by wind turbine with a button in the car. Fuel consumption can be reduced using wind turbine. Generator is driven by engine pulley system when vehicle starts, it will be occupied about 30% fuel consumption by this type generally. The generator can be switched driven by wind turbine while the vehicle moves at a stable speed on road, fuel consumption can be reduced about 15% by the wind turbine. The charge type can be set to wind turbine system when car speed is higher than 50kilometers, and the higher, the more efficiency. While wind turbine system will self-stop when wind speed is too high at car speed more than 120 kilometers for safety. The road experiment results revealed that proposed vehicle wind turbine system saved about 15% fuel consumption when car speed is higher than 80 kilometers.

https://ieeexplore.ieee.org/document/8394544

What other energy can we harvest?

I still want a “boost” button - KERS for my little hot hatch!

ZHP Sparky, the 5th > davesaddiction @ opposite-lock.com 09/08/2020 at 12:21

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Put bicycle pedals at all the passenger seats and market it as a workout while you travel. 

ZHP Sparky, the 5th > ZHP Sparky, the 5th 09/08/2020 at 12:27

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Sorry, just being a smart ass. The suspension sounds like a great idea in theory - wonder how complex/effective it would be.

Doesn’t the new Hyundai Sonata have a solar roof option that supposedly saves a couple of miles of gas a day? It’s not much, but could be a great backup/why not as the tech gets cheaper over time . We recently got a small 60W solar charger panel for camping - it’s crazy seeing that thing drawing 50W on a regular basis to charge up our devices.

DasWauto > davesaddiction @ opposite-lock.com 09/08/2020 at 12:50

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First law of thermodynamics: Conservation of Energy: Energy cannot be created or destroyed. Which is to say that the energy it would take to push the turbine through the air is at least equal to the energy the turbine can generate (ignoring friction losses).

One could argue that you could deploy a wind turbine while braking, in effect another sort of regenerative braking but I doubt it’d be worthwhile.

After re-reading the quote many times (terrible grammar) , it seems to be suggest having the alternator driven by a wind turbine rather than the engine when the car is at speed. Interesting idea, but I’d seriously doubt a 15% reduction in fuel consumption being anywhere near achievable. Read: I don’t think the alternator draw accounts for 1 5% of fuel consumption at those speeds. I can believe 30% at idle if it’s charging fully but I don’t think that’s constant (not sure how the charging system in a car is controlled/programmed). 

Spanfeller is a twat > davesaddiction @ opposite-lock.com 09/08/2020 at 13:01

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Adding devices to capture energy loss from every mobile part in a car
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Making a car lighter and simpler so that the energy loss does not present such a significant impact.

Thank you for joining my TED talk. 

facw > DasWauto 09/08/2020 at 13:05

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Yep I don’t see how those claims are possible except by using it to increase wind resistance when the care is stopping, but it’s not clear why that would work any better than regenerative braking.

davesaddiction @ opposite-lock.com > Spanfeller is a twat 09/08/2020 at 13:19

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I enjoyed it.

Future next gen S2000 owner > davesaddiction @ opposite-lock.com 09/08/2020 at 13:23

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Solar panels are a good idea for AC type stuff. It wouldn’t add any meaningful amount of range but ancillary stuff.

I have my suspicions about that wind turbine. I wonder how they controlled for head winds versus tailwinds. It seems, per the snippet, that they are getting a positive net energy when drag is taken into account which doesn’t seem likely.

davesaddiction @ opposite-lock.com > DasWauto 09/08/2020 at 13:34

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So, you’re already using a large amount of energy to move the car at highway speeds. What if a system was created that barely increased drag, but routed airflow internally where there were turbines that would be turned? Now, I realize that the turbines would have to be connected to a battery which would increase resistance...

In a hydroelectric system, you’re removing kinetic energy from the flowing water. Wind farms removes kinetic energy from passing wind (possibly causing warming?). In the scenario we’re discussing, assuming zero natural wind, the “wind” is created by the car passing through it, but since it was going to pass through anyway, is much of the kinetic energy in the “wind” just lost to turbulence in the car’s wake (think of the massive energy coming off of a tractor trailer as you pass by)? Is there a way to capture some of it that does not significantly increase the energy it takes to move the car at those speeds in the first place?

davesaddiction @ opposite-lock.com > Future next gen S2000 owner 09/08/2020 at 13:36

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Yeah, you could use it to run a small fan to vent the interior on a hot day so the AC doesn’t have to work as hard to cool the cabin.

I’m not sure either - see DasWauto’s comment and my reply.

WRXforScience > davesaddiction @ opposite-lock.com 09/08/2020 at 14:07

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Drag is the primary force a car at highway speeds has to overcome, marginal increases in drag result in dramatic increases in fuel/energy consumption.

Drag is direct ly proportional to the cross-sectional area of the object; however, with a spinning prop eller the drag also has to include the parasitic losses in the propeller system (friction of the bearings as well as the drag the propeller blades experience which will be greater than their stationary drag since the drag is also proportional to the speed of the object and the propeller tips will be moving quite fast).

davesaddiction @ opposite-lock.com > ZHP Sparky, the 5th 09/08/2020 at 14:07

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The suspension is a cool idea, but probably not really worth it for the cost/complexity/benefit.

I’m looking forward to solar systems getting better & cheaper . The back of our roof is south-facing and I’ve been considering more and more.

fintail > Spanfeller is a twat 09/08/2020 at 14:14

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S-class becoming simpler? That’d be a first. Maybe some weight loss between 140-220 and maybe even 116-126, but that too isn’t a thing.

I just hope this ages better than 220/ABC suspensions.

Spanfeller is a twat > fintail 09/08/2020 at 14:17

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I understand that in some areas the gains are superior to the losses ; specially considering regulations are sometimes shortsighted and meeting them is probably the most important goal . I trust the engineers made many complicated calculations I’d struggle to understand in order to justify that equipment...

TorqueToYield > davesaddiction @ opposite-lock.com 09/08/2020 at 14:18

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EV power generation you say?

https://www.cnet.com/roadshow/news/chinese-company-tests-turbine-driven-electric-super-car/

fintail > Spanfeller is a twat 09/08/2020 at 14:20

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I don’t know if the S gets better with each versio n - many argue against that (I am not a fan of the touchscreens/ICE in the new one), but you know how Germans like it, complexity for the sake of complexity, just because you can.  Showing off is part of the justification, no doubt.

davesaddiction @ opposite-lock.com > TorqueToYield 09/08/2020 at 14:26

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a turbine is much more efficient than an internal combustion engine, at least when used as a generator. The turbine in the TREV spins at 96,000 rpm, and Techrules has built one using gasoline and one using aviation fuel

Cool!

BigBlock440 > davesaddiction @ opposite-lock.com 09/08/2020 at 19:49

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I don’t see how adding a wind turbine would be any different than strapping an alternator to the axle

DasWauto > davesaddiction @ opposite-lock.com 09/08/2020 at 21:30

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Internal or external you’ll be adding drag. That added drag will never take less energy to overcome than can be generated by a turbine. Unfortunately, the laws of thermodynamics are as inconvenient as they are accurate.