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MIT Team Creates Shock That Recharges Your Car
An anonymous reader writes "If you had a GenShock, you may not mind those potholes in the road any longer because this new prototype shock actually harvests energy from bumps in the road to save on fuel. A team of students at MIT have invented a shock absorber that harnesses energy from small bumps in the road, generating electricity while it smooths the ride more effectively than conventional shocks. Senior Shakeel Avadhany and his teammates say they can produce up to a 10 percent improvement in overall vehicle fuel efficiency by using the regenerative shock absorbers. They also already have a lot of interest in their design, specifically the company that builds Humvees for the army are already planning to install them in its next version of the Humvee."
Looks like MIT just gave us a little picklet, will we repair our roads or use the potholes to power our cars?
Is this actually legal since it hurts the oil industry ?
I hope you are being silly. The most efficient way to travel would be a perfectly smooth road, one that didn't suck energy out of the vehicle, in the form of a bump, in the first place.
To truly express the dilemma, you have to weigh the amount of energy used to maintain a smooth road versus the new found energy return from these shocks.
Recharging the batteries using movement of the shock absorbers is ingenious!
That they would smooth the ride more than conventional shock-absorbers is bullshit. You can get all kinds of traditional shock-absorbers. American ones for instance are typically softer than European which leads to poor handling and increased fuel consumptions. European ones are harder, and sports-models even harder yet, given the cars better handling at the expense of ride comfort.
If the new absorbers are smoother than traditional ones, it just means the car can't corner, and rides like a pimp car.
Which is why this makes sense for off-road vehicles, such as military hummers.
But I agree that poor road maintenance is not just a suck on fuel efficiency, but results in increased costs on the upkeep of vehicles as a whole. (and it takes energy to make and ship those new sway-bar struts that I had to have replaced because of hitting too many bumps)
Build it, and they will come^Hplain.
should s/shock/shock absorber/ so we know WTF you're talking about right away.
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E pluribus sanguinem
This is pretty good.
In their testing so far, the students found that in a 6-shock heavy truck, each shock absorber could generate up to an average of 1 kW on a standard road.
The total insolation at the equator is about 1kW per square meter, so if your solar cells are 20% efficient that's the equivalent of 30 square meters of solar panels.
("up to an average", though... wtf does that actually mean? Oh well, your solar cells only get "up to an average" of 1kW too...)
I take it you don't live in a cold weather climate or in a large city. Snow/ice + salt + plows = pot holes. Large cities have notoriously bad roads, it's too hard to repair them with so much traffic.
And it's not just bumpy roads that shocks help with. Every time you turn a corner the shocks are used to keep the car stable.
Personally, I think it's a brilliant idea. The easiest way to become more efficient is to turn the wasted energy into something useful.
"Action without philosophy is a lethal weapon; philosophy without action is worthless."
I've been saying for 5 years now that we should use all the available energy to power electric cars. Shock absorbers are one step, but combining it with solar cells, small wind generators deployed while coasting, regenerative braking, coupled with supercapacitors and a plug to recharge when necessary, that would be truly innovative.
I think that this is the way of the future, and MIT did one step.
Cars are brought back to their parents on prom night with a full tank of gas.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
Bose admitted to pre-tuning their magnetic suspension specifically for each demonstrated feat. Changing one without changing the other would destroy the so-called "advantage".
Also, the system is hideously expensive, impractical and performs poorly compared to conventional equipment. A bit like every single other crappy product Bose has ever made, really.
Eat the rich.
Generally speaking you have more handling and fuel performance issues with having too *little* air in the tires. 27% of cars, according to the US DOT, have at least one underinflated tire.
http://www.dot.gov/affairs/nhtsa4601.htm
So what's the problem? Well, as you say, you get a harsher ride from an overinflated tire, but you get far many more problems with underinflation, which is probably far more common. Some of those problems include poor braking, slow steering, poor handling/road grip, and worse fuel economy... worse than can be made up by funky new regenerative shocks.
http://www.straightdope.com/columns/read/225/could-we-conserve-gasoline-by-putting-more-air-in-our-tires
I know lots of people made fun of Barack Obama during the Presidential campaign for his plea to check the tire pressures, but the reality is that drivers the world over could save millions of gallons of oil annually by simply keeping tires inflated properly. In cold climates this also means double checking the pressures when the outside temperature drops by 10 degrees.
Better to pump up the tires than not.
This post brought to you by your friendly neighborhood MBA.
I wouldn't be surprised to see tractor-trailers going hybrid soon. Fuel economy is a HUGE factor for trucking, and they require large engines to maintain speed up large inclines. Additionally, all that weight is very hard to slow down on declines -producing a lot of wear on brakes and power-train (engine breaks). Trains already do it, trucks are next.
"Knowledge is the only instrument of production that is not subject to diminishing returns" -Journal of Political Econom
I'll take the "poorly modified" up-armored vehicles over a canvas passenger compartment on my patrol of Baghdad any day. When we were in Iraq in 2004-5 my brigade lost a few soldiers, but at least as many and probably more were saved by vehicle armor as were lost. The armor provided some maintenance headaches for sure, but I'd rather (and the mechanics, would rather, especially since they ran in the same vehicles when they went outside) the mechanics have to work a bit harder than having the fatality rate double. Would it have been better if we have an existing light armored fighting vehicle deployed to all of our troops? Yeah. Was the solution a damn sight better than the problem it fixed? Ohh yeah.
I don't need a million points of light, just two points of multi-mode fiber and a 10 Gig-E router.
At first glance this sounds like a good idea, but let's do the math.
Assume you're driving over an evenly and heavily potholed road, such that all four wheels are rising and falling four inches four times a second. That's a very generous assumption. And assume a rather pudgy 400 pounds of unsprung weight. To move that stuff 1.33 feet per second takes 900 ft-lbs.sec of power, about 1.5 horsepower. But you don't want to absorb all that power or the whole point of a flexible suspension is lost. Let's guess we want a Q-factor of about 3, that is, we absorb 1/3 of the energy per cycle. We're down to 0.5 horsepower, and that is under optimally bumpy conditions. And small random jiggles are hard to capture as electricity. Overall it does not seem to be worth harvesting.
If one is going to be driving on such surfaces a lot, it makes a whole lot more sense to fit the vehicle with larger flotation-type tires. Those tend to flex and span potholes, so the car and passengers don't jiggle at all.
You do realize that this will only effect hybrid or electric cars right?
Here is some things to consider, in 2006there were a little over 135 million registered passenger cars in the US. Now that's not counting pickup trucks that had to be registered as commercial vehicles but are still used as personal vehicles. Since 2000, not more then 2.5-3 percent of new car registrations have been to hybrid vehicles or electric vehicles until 2007 which saw around 5%. This means that this can effect less then 10% of the passenger vehicles on the road and more likely that number is much lower.
The second thing is, if these shocks produce a gain of around 10% in energy recovered, then we can do some math on the economics of it. If a hybrid electric car gets 60 MPH, Some say on 40, and they travel an average of 1500 miles a month, then we can find how much 10% is worth. So 1500/60 and 1500/40 respectivly come out to 25 and 37.5 gallons of fuel. At $2.00 a gallon, that would be about $50 a month for the 60MPH and $75 a month for the 40MPG. A 10% savings of them would be $5 and $7.50 per month savings. Regular shocks wear out after about 5 years or so of driving, some last around 10 years before they are noticeably shot. So $5 * 12 months * 10 years means this device would only save about $600 and $900 over ten years. That's the price point they have to beat in order for there to be a savings. If they can't get the cost of this stuff under those dollar figures, then they are probably costing more then any savings.
My guess is that their effectiveness is going to go as the shock absorption abilities go and will only be effective for that typical 5 years then severely degrade after that like regular shocks and struts seem to do. The concept doesn't seem to be much different then a wave generator but applied to an existing gas or oil filled cylinder instead of hydraulic pistons connecting floats. This means that they will have to create a valve system and generator and a way to connect it to the cars power inputs. They might be able to do that for less then $6-900 every ten years. But I doubt it.
(My father in law drove an 18 wheeler at one point).
So much of the 18 wheeler relies on moving air around pneumatically. The two basic forces in an 18 wheeler are positive pressure and vacuum. If you do away with the engine (or otherwise turn it off), you lose the boost/vacuum economy which makes those accessories work. While you could probably come up with some weird stopgap - they already use compressed air tanks as a backup - the retrofit to make it work with existing trailers would far outweigh the savings from a hybrid cab. Add to this that the truckers rent or own their own cabs as part of the business and there's little incentive for anyone to innovate or upgrade in a direction that would hurt their prospects for hauling.
http://en.wikipedia.org/wiki/Joint_Light_Tactical_Vehicle
The next military truck might not even be from the company that makes the HMMWV. BTW, most of the JLTV entrants (if not all? It might be a program requirement...) are hybrids. The military wants increased fuel efficiency for logistical purposes.
retrorocket.o not found, launch anyway?
Wonder if I can have this on my bed.
Honey, I know you have a headache, but think of the planet.
I did a ton of shock development as part of my race car engineering job.
We had sensors on the suspension to directly measure suspension travel, with a view towards measuring suspension velocity as part of shock development.
Even on what feels like a perfectly smooth track, there's still a lot of humping and bumping going on.
See http://farnorthracing.com/autocross_secrets6.html for example graphs of suspension velocity pulled right off the car.
DG
Want to learn about race cars? Read my Book
OTOH, if you're running low on fuel/power, just cruise up onto the sidewalk and mow down a few unsuspecting pedestrians. *KaThumpKaThump* *KaThumpKaThump* Presto! Enough juice to make it home (after a quick run through the carwash, of course). Thanks, MIT!!
"a shock absorber that harnesses energy from small bumps in the road"
It doesn't create energy, it only recovers a certain percentage that would have been lost otherwise.
As such, it'll only be practical on rough terrain, poor quality roads, or when you intentionally drive over potholes . . .
You do realize that this will only effect hybrid or electric cars right?
Given the specific mention of military hummers, which are most certainly NOT hybrids or electic, it must have some benefit for non-hybrids.
Then again, how difficult would it be to replace the starter and alternator with a motor/generator capable of putting power to the drivetrain? Even if it's only a 5hp sustained, that'd be more than enough to take the 1kw each of the six shocks is capable of putting out(1hp=746W). Switch out the lead battery for a LiIon/NiMH of substantially more capacity. Increased cost, but probably actually lighter than traditional systems. For cold areas, there are LiIon that perform *as rated* at -40C. Not the 'put a bigger battery than you could possibly need in warm weather so you still have enough power to start when the oil is like jelly and the battery has 10% capacity left'.
You'd end up with a mild hybrid that can do stuff like shut off the engine at stops. Oh and stick the energy gained from the shocks back into moving the vehicle.
If they can't get the cost of this stuff under those dollar figures, then they are probably costing more then any savings.
The only problem I see with your figures is that they're explicity talking about trucks and other heavy vehicles. So you might want to redo your figures for 12-20 mpg ranges. Their test mule was a heavy truck with six shocks. Indeed, they also mention that it provides a better ride than traditional shocks, so there's a possible selling point there.
20 mpg/15,000 miles=750 gallons. Save 75 gallons a year(10%), that'd be $150@$2 gas, $300@$4 gas. Ten year timeframe? Could save them $3k, more if they've got a really heavy truck or are driving on particularly bumpy roads.
Then again, I've said numerous times that it makes more sense to make trucks and SUVs hybrid before you start making sub-compact hybrids. More fuel to save, more room to put the components, components end up being a lower percentage of the cost of the vehicle, etc...
I mean, look at the typical UPS/FEDEX panel van. Consider it's usage - stop and go traffic all day in the city for most of them. Right now they have a diesel engine that doesn't get turned off when they stop. How much fuel can be saved if you turn the truck into a hybrid? As a bonus, the heavy battery pack in the bottom of the vehicle would help mitigate the tipping hazards of a tall vehicle like that.
My guess is that their effectiveness is going to go as the shock absorption abilities go and will only be effective for that typical 5 years then severely degrade after that like regular shocks and struts seem to do.
Might last longer due to the nature of the energy absorbtion, but you're right. A lot of cost and durability issues need to be resolved.
I don't read AC A human right
Let's respond point by point.
...your 2nd paragraph yields number of cars affected...
You do realize that this will only effect hybrid or electric cars right?
Yes. This will only affect some present and most future cars. Sorry to have disturbed you with it.
Ok, let's agree on less than 10% of passenger cars today. I can add that it affects zero% of my car(s) -- an equally irrelevant fact.
The second thing is, if these shocks produce a gain of around 10% in energy recovered, then we can do some math on the economics of it.
We sure can, and the bottom line is that for 5% of the cost of a $20K car, you can get 10% better fuel economy. [2.5% of a $40K car, 1% of a $100K car, 0.1% of one of these] This "spend 5%, get 10%" thing should already be a clue but here is a back-of-the-envelope calculation anyway: over 150,000 miles, a 25mpg car will use 6,000 gallons of fuel. 10% of that is 600 gallons. At today's price, that is about $1,200, FTW. 5 or 10 years from now it will be higher.
Also, 10% more energy translates to a savings in weight somewhere else. For example, the batteries can be 10% smaller, and a 10% battery weight savings could lead to a further 10% gain. Yes, adding a small "Shock Energy Recovery System" to each wheel would add weight, but most likely not equal to 10% of 68KG. And those 68KG only take a Prius for about 5 miles (currently). The next gen is going for 11 miles of electric-only range, so scale the battery weight accordingly. And that is the point -- if you scale the battery range to 50 miles for example, the weight goes to 680KG, and the SERS savings becomes 68KG since it is not necessary to scale the size/weight/cost of the SERS system.
My guess is that their effectiveness is going to go as the shock absorption abilities go and will only be effective for that typical 5 years then severely degrade after that like regular shocks and struts seem to do.
Bad guess -- electrical systems last vastly longer than purely mechanical systems like a shock absorber. SERS could be an induced system, without physical contact, and thus without wear.
And how about just having an extended vehicle range? If you live 5.5 miles from work, your present day Prius will still have to fire up its gas engine. Add SERS and you don't need the gas. If you presently change the oil every 6 months, now you change it every 6.6 months. And unlike engines, and batteries, the SERS can be designed to not wear out at all -- so you extend the total life of your car, bringing further savings.
I think I'd like to let the marketplace decide, rather than choosing to not offer this product because it might just break even in some initial/present day cases. If SERS causes excitement and optimism, people will want to move toward electric and electric/hybrid systems even more -- and that would bring lower prices and more savings.
The future is in plastics, and SERS-like systems. I find your post well reasoned...for a 1900s buggy whip manufacturer.
I come here for the love
What about cutting out the hydraulic middle man and just have a coil of wire on the shock moving through a magnetic field?
In fact it will have a net negative effect on your gas mileage. If you put an electric (re)generator on a shock absorber, and hook it up to an electrical load (to capture the energy) then the generator will fight back when the shock absorber tries to react to the pothole. In effect, it will directly reduce the "shock absorbing" capability of the shock absorber, giving you both a rougher ride and slowing your car down more.
Since there are always losses in energy transfer, the amount you "recover" will always be less than the amount put into the system by you having to use more gas as a result of the harder bump.
It's called Back EMF, basic high school physics.
Beware the Wikipedia article on Back EMF, it loosely covers the concept but the article links to a "serious" entry about a perpetual motion machine called Perepiteia, which also would violate the laws of thermodynamics.
The "inventor" "doesn't understand how it works" and yet worked "8-12 hour days on it" making a transformer 7000% efficient!
Sigh..
Bavarian Purity Law of Rice Krispie Squares: Rice Krispies, Marshmallows, Butter, Vanilla.
The military is all about electric drivetrains. Stuff isn't necessarily deployed, but they burn a lot of diesel and carry around generators, so they are very interested in things that save diesel or put a generator in every truck.
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TROLL FIGHT!
My sig can beat up your sig.
Might last longer due to the nature of the energy absorbtion, but you're right. A lot of cost and durability issues need to be resolved.
Think along the lines of the shake-charged flashlights. The only things added to a regular shock are a coil and a magnet. The magnet isn't going to wear out in any reasonable time-frame, and a properly insulated and protected coil won't either (unless the temperature starts to affect the insulator - unlikely, and can be mitigated with engineering). I suspect they would last about as long as regular shocks unless they completely replace the standard shock-absorption part. That seems unlikely - a wire breaks (or nothing needs to be powered) and your shocks turn into springs. The mechanical parts will wear out faster than the electrical parts.
The other thing the GP forgot to mention is, current-technology shocks aren't free. They can be more expensive than current shocks, so long as they pay for themselves in a reasonable time-frame, say 2 to 5 years or their lifespan, whichever is shorter.
Sure I'm paranoid, but am I paranoid enough?
will be on the lookout for new shocking disc-recoveries?
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