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Bose Electromagnetic Suspension
September 20, 2007 6:54 PM   Subscribe

"The grand finale was something out of a Matrix-style movie. A two-by-six piece of wood was placed on edge and the Bose car drove toward it at moderate speed and then leapt over the board as elegantly as a cat, touching down softly." Edmunds reviews the new Bose electromagnetic automobile suspension.
posted by mr_crash_davis (91 comments total) 5 users marked this as a favorite

 
Kit, engage turbo boost!
posted by spikeleemajortomdickandharryconnickjrmints at 6:59 PM on September 20, 2007


That's "Kitt, not "Kit".
posted by spikeleemajortomdickandharryconnickjrmints at 6:59 PM on September 20, 2007


So... Bose makes a quality product? That is news.
posted by revmitcz at 7:01 PM on September 20, 2007 [8 favorites]


Wow. That video clip really is spectacular. No more speed bumps!
posted by Kraftmatic Adjustable Cheese at 7:03 PM on September 20, 2007


Wow. I want to know how it feels to drive with that.
posted by blacklite at 7:05 PM on September 20, 2007


Just what we need ... something that lets drivers zoom down my back street, ignoring the speed bumps ...
posted by woodblock100 at 7:09 PM on September 20, 2007


God damn.
posted by middleclasstool at 7:14 PM on September 20, 2007


ausgezeichnet!
posted by localhuman at 7:16 PM on September 20, 2007 [1 favorite]


woodblock100 says what I'm thinking, but middleclasstool says what I feel.
posted by Alvy Ampersand at 7:17 PM on September 20, 2007 [2 favorites]


That is extremely cool, but it must use insane amounts of electricity.
posted by Pastabagel at 7:19 PM on September 20, 2007


Leave it to Bose to take all the fun out of hard driving.

The EVO don't need no Bose suspension... Tripod mode, w00t!
posted by BeerFilter at 7:21 PM on September 20, 2007


Dayum.

The wonders this could do for my P.O.S. 1989 Dodge Ram.
posted by Kickstart70 at 7:22 PM on September 20, 2007


Sweet. I wonder if it jumps spike strips? That would make the ultimate get away vehicle.
posted by Mr_Zero at 7:29 PM on September 20, 2007 [2 favorites]


So long to hit'n switches and getting front and back and side to side...
posted by wfrgms at 7:29 PM on September 20, 2007


@Pastabagel

It uses the same principles of regenerative braking to get most of it's own power back, minimizing overall efficiency losses.

They say it uses 1/3 of a standard air conditioners power. I wouldn't expect it to lower total power efficiency by more than 1%-2%.

One could argue that the overall benefit (which is really amazing to see in person) far outweighs the cost.

Replace the alternator with a high-output model ($50-$60 on eBay - right now!) and there is no significant strain added to the electrical system.

This is very significant and a version of this (either from Bose or a copycat) will probably show up in high-end luxury sedans in a couple of years. Trickle down to something like Civic might show up in 10-15 years.
posted by astern at 7:36 PM on September 20, 2007


Trickle down to something like Civic might show up in 10-15 years.

Which means it will make it into American built cars in 25-30 years.
posted by Mr_Zero at 7:38 PM on September 20, 2007 [2 favorites]


Too bad the real cars won't have the boost button they used to jump over the board at the end.
posted by smackfu at 7:40 PM on September 20, 2007


...touching down softly.

Well, then, this is not an eponysterical post!

But hey hey hey! How 'bout that Nissan independent suspension, eh? Eh? Now that's what I'm talking about! (maybe NSFW...)
posted by flapjax at midnite at 7:43 PM on September 20, 2007 [3 favorites]


Bose obsoletes the speed bump, the traffic calming half-circle and rumble pavers.
posted by stbalbach at 7:45 PM on September 20, 2007


@Mr_Zero

Most domestic small economy cars are built on global platforms that are actually reliable and worlds better than what you might think GM, Ford or Chrysler would normally produce.

This is not your father's Nova...
posted by astern at 7:47 PM on September 20, 2007


All I could think of was this, especially the first 15 seconds.
posted by peeedro at 7:55 PM on September 20, 2007


I CAN HAS CONTROL SYSTEMS?
posted by TheOnlyCoolTim at 7:55 PM on September 20, 2007 [1 favorite]


This is very significant and a version of this (either from Bose or a copycat) will probably show up in high-end luxury sedans in a couple of years. Trickle down to something like Civic might show up in 10-15 years.

Probably not. Mercedes has had self-leveling penumatic suspension as an option on the S-class for 30 years now. The Bose system will suffer from the same problem - extremely expensive maintenance.
posted by b1tr0t at 8:00 PM on September 20, 2007


How long until the rally world cup either incorporates or bans this?

One (potential) disadvantage I can see of this system is that it removes yet another source of driver feedback - first power steering disconnected you from the 'feel' of the tire grip, now this active supension will disconnect you from an indicator of the car's grip. People may try and howl through the traffic calming half-circles, but their tires won't have anymore grip than they did before.
posted by anthill at 8:08 PM on September 20, 2007


So... Bose makes a quality product? That is news.

Oh no, you've got it wrong.


Bose makes a quality product and doesn't charge double for it to pay for rampant advertising (yet)?

Now that's news...

In all seriousness, I am torn between the awesomeness of such a great suspension system and the anesthesizing effect on those drivers who already think that traction control features are a free license to drive 50MPH in blowing snow on top of ice.

Give me a test spin in my Outback wagon and I'll let you know if it's better than Subaru AWD...
posted by rollbiz at 8:17 PM on September 20, 2007


anthill, while I agree with you, wasn't this a very similar argument that fighter pilots made when they started using computers to control flight (and fighters are now so non-naturally flyers they need a computer to keep it airborne)?
posted by porpoise at 8:17 PM on September 20, 2007


Active suspension isn't exactly a brand new notion, but I guess this is probably the first fully implemented electromagnetic suspension. It certainly is an impressive demonstration!

Bose obsoletes the speed bump, the traffic calming half-circle and rumble pavers.

If the speed bump is taller than the suspension travel, going over it at speed will mess up the car no matter the technology (I'm not sure how suspension travel is designed relative to ground clearance though.. Certainly if you designed the car around typical speed bump heights, you could do it). I'm not sure what you mean about the half circles - just that it can corner faster? And, I don't think it would be designed to filter out rumble strip type vibration, which is very high frequency compared to anything you would normally run into on a road.

Anyway, I bet it uses a lot more energy than they are willing to admit. Sure, you can use Class-D amplification to keep the power supply efficient, but the electromagnets are still going to be coils of copper..
posted by Chuckles at 8:21 PM on September 20, 2007


extremely expensive maintenance


yup - first time you get a quote @ $1200 per strut out they come and in go the plain jane $98 specials.
posted by CynicalKnight at 8:26 PM on September 20, 2007 [1 favorite]


It uses the same principles of regenerative braking to get most of it's own power back

Ya.. The energy use is interesting to think about. It is the straight level driving that will use the most. I can't think of any way you could lock it off, the response time would be ruined. So, you will always be powering the electromagnets with enough current to support the cars weight (doing no 'work', but consuming a lot of energy :P).

Other than the steady state power consumption, regenerative suspension would actually be more efficient than normal, of course, which is pretty cool!
posted by Chuckles at 8:30 PM on September 20, 2007


Active suspensions, similar to this one, were all the rage in F1 during the early 90's until they were banned. The main benefit for them was the ability to control ride height independent of aero load. obviously, Bose is going for the shock and vibe isolation vs precise ride height control. and the Bose system won't have the high speed sled failure mode of the old F1 suspensions because there is actually a spring holding the vehicle up that the active system overrides or assists depending upon which way the wheel needs to move.

Maintenance shouldn't be a big issue with these because it's just a big linear motor, one moving part and the power electronics should be reliable. The real question is how does it behave when the bump height exceeds suspension travel (hello bumpstop), and how far down that bumpy road can you drive before the coils overheat and your driving a completely undamped car thats sprung softer than a Caddilac.

As for the comments about removing driver feedback, the amount of body roll and pitch movement can be programmed into the controls software, it doesn't have to completely block out any body movement, in fact it really shouldn't eliminate all of it just so unskilled drivers have some feedback before they go sliding off into a ditch or roll over their SUV.
posted by TheJoven at 8:32 PM on September 20, 2007


[Bose is known for] expensive but worth-the-cost systems for the home

Bose usually sounds okay, but their products are cheaply made and vastly overpriced. You can usually get much better sound for the same price, or equivalent sound a lot cheaper. There's a reason why Bose products are virtually never set up so that you can do a proper A/B test with other equipment; Bose won't allow it. You can infer who would be likely to lose such comparisons.

Bose is a marketing-driven company; their primary function is to convince you that their products sound better. Actually making products that DO sound better is almost entirely irrelevant. They usually sound okay, and if you can actually set up a true A/B listening test with several different flavors of speaker, and you like the Bose the best, by all means buy them. But don't if you can't properly compare. Because auditory memory is so short, the only way to do it is with an instant switch between sound sources. A blind test is even better, but those are hard to set up before you actually own the equipment.. a straight, sighted A/B is usually the best you can manage.

As far as this new suspension goes... let's just say that if I were buying cars in this market, I don't think I'd be an early adopter. Marketing-driven suspension scares me.
posted by Malor at 8:34 PM on September 20, 2007 [3 favorites]


I want it. But I want to be able to turn it off at will; sometimes it's nice to feel the road.

The whole maintaining a perfectly level vehicle over rough ground thing is really reminding me of Charlie from Bruce Sterling's Heavy Weather.
posted by quin at 8:39 PM on September 20, 2007


there is actually a spring holding the vehicle up that the active system overrides or assists depending upon which way the wheel needs to move.

Ya, that should have been obvious... I mean, like cars don't already do that :P   D'oh!
posted by Chuckles at 8:46 PM on September 20, 2007


>So... Bose makes a quality product? That is news.

Amusingly, the selling point is presumably how low quality this suspension is supposed to be.
posted by johnjoe at 9:03 PM on September 20, 2007


Here's a beautiful ad from the 1980 ad for the Isuzu Gemini. Some gorgeous choreography and amazing jumps. I'm not normal keen on cars, but they don't normally jump like salmon.
posted by sebastienbailard at 9:57 PM on September 20, 2007 [4 favorites]


for some reason, this video linked from the youtube video convinces me that current suspension technology may be good enough (may be NSFW)
posted by jeffmik at 10:22 PM on September 20, 2007


Bose marketed this system as "ready" a few years ago too. Seems like he's had no takers from the auto manufacturers. Presumably it's not quite ready for prime time.
posted by Harald74 at 11:45 PM on September 20, 2007


The 'review' reads like a Bose press release. The video looks impressive.

At this point, all seeming objectivity on the matter has come from to me through the comments in this thread. I'm curious if anyone not currently in a romantic relationship with the developers will report on this soon.
posted by Bokononist at 12:53 AM on September 21, 2007


What Malor said, above.

Bose today isn't about hi-fi. At one time it was, but not anymore, not in the consumer market - and no one uses Bose speakers in the pro market.

There's a couple of kinds of vintage Bose pro-audio PA and a couple of monitors that are quite, quite nice as far as clarity and warmth - but it's still not worth paying a premium for. Picking them up used and cheap, sure, but not at a premium.

You'd be better off buying modern speakers, like the nearly bullet-proof and relatively affordable Mackie High Resolution Near Field series for studio monitors.

But those super pricey "cube" Bose home theater systems? You'd be better off buying an off-the-shelf home-theater-in-a-box from someone like Yamaha or even Sony, dollar for dollar. Bose is way overpriced and underpowered.
posted by loquacious at 1:40 AM on September 21, 2007 [2 favorites]


Crap, the next time I have an idea like this, I should maybe think about patenting it, instead of sitting on it for years until someone else comes up with it. On second thought, they probably have been working on it for ten years or more anyway.
posted by BrotherCaine at 1:52 AM on September 21, 2007


Onkyo HTIBs have a very good reputation in the geek sound community. I don't have any of their speakers, but I have had several of their receivers, and they have been uniformly excellent. I'd suggest checking them out if you're in the market.
posted by Malor at 2:14 AM on September 21, 2007


Doesn't being this compliant over bumps cause for less tire contact? Wouldn't that affect braking? I'd also be interested in seeing how it would handle if the driver were taking a curve at high speed, then hit bumps in the middle of the apex.
posted by SteveInMaine at 3:08 AM on September 21, 2007


Crap, the next time I have an idea like this, I should maybe think about patenting it, instead of sitting on it for years until someone else comes up with it. On second thought, they probably have been working on it for ten years or more anyway.

I know how you feel. Since I was about 14 I've thought about how cool it would be, specifically with regard to speed bumps, to put a distance sensor just under the front bumper facing down, and tie that in with a speed sensor in order to calculate the height of an upcoming speed bump and move the wheels up and down with it.

This is much, much cooler.
posted by odinsdream at 4:23 AM on September 21, 2007


Crap, the next time I have an idea like this, I should maybe think about patenting it, instead of sitting on it for years until someone else comes up with it.

You probably wouldn't have been the first one anyway. People (definitely not just Bose) have been thinking about active electromagnetic suspension systems so much, there is even a European Patent Classification category just for that kind of idea.

One thing is to think of the basic concept (done a long time ago). Another thing is to solve the basic engineering problems to get a working prototype (what Bose, and probably quite a few others have done now), and finally an even more difficult thing is to solve the manufacturing, cost and maintenance problems to bring it to production. Apparently, we are not quite there yet (but getting closer).
posted by Skeptic at 4:52 AM on September 21, 2007 [2 favorites]


That is a neat video, but I'd still go with conventional suspension. I like feeling the changes in the road (and the rumble strips if I'm going off the highway late at night . . .).
posted by schroedinger at 5:29 AM on September 21, 2007


With great power comes great responsibility.

Assuming this does get truly productized, and people can easily ignore speedbumps and rumble strips, it's only a matter of time before the speedbumps get made so tall they overcome even an active suspension. Which will be even more annoying for those without an active suspension.
posted by tommasz at 6:32 AM on September 21, 2007


This is just one step away from the reactive spoke wheels of Neal Stephensons Snow Crash.

Personally, I'll wait for the wheels, Let the early adopters of these shock pay for the development costs.

Who whooda thunk Bose...
posted by djrock3k at 6:37 AM on September 21, 2007


What loquacious said above about what Malor said above that.

And, just a little tip, those interested in some damn good speakers with some seriously true and uncolored sound with, like, no masking are urged to check out some of the products from the German company ADAM.
posted by flapjax at midnite at 6:55 AM on September 21, 2007


Finally, modern suspension design begins to catch up with the Dukes of Hazzard.
posted by sfenders at 7:03 AM on September 21, 2007


As far as this new suspension goes... let's just say that if I were buying cars in this market, I don't think I'd be an early adopter. Marketing-driven suspension scares me.

I hope you don't want to drive any of the (externally developed *cough*) Subaru special editions then (P1, etc), as the marketing department were the principle deciding factor in the suspension on that (pissed the proper suspension boys off no end). The 'feeling fast' element over actual maximising of grip was the deciding factor of the end product.

Man, the arguments I heard from insiders on that was seriously heated...

Active suspension is a hugely old concept. I've seen videos of this type from 20 years ago. Just doing it more cost effectively is the recent advance. As mentioned, F1 had active suspension in the mid to late 80's (Lotus developed it in 1981...) and even Citroen's self levelling in the DS of 1955-75 is essentially active suspension.

It is purely the concept of keeping the body level and so the weight on all wheels constant. The perceived 'loss of feel' is also moot. The car moves and transfers weight - you don't feel grip like that, you feel it through the tyres. Modern racing cars hardly move anyway (we're talking sub 10 mm of suspension travel - much less in F1) yet the drivers don't have any trouble feeling the limit of the grip - the car moving just gives you a big red flag as to when that is going to be.

People's ideas of how a car feels and their ability to drive it with those inputs is just familiarity. If you didn't know a car moved before losing grip, you'd never need it. It's just what you are used to.

The jump at the end is a gimmick. The car is unable (from reading the article on the sensors and the like that it has) to predict and jump an obstacle, as it is a reactive system, not a magic carpet. They just set it up to do an extreme weight transfer that allowed the system to pick the wheels up as much as it could (it used the brakes and power for weight transfer too) and stuck a suitably sized obstacle underneath it for demonstration purposes. The car didn't 'just jump a block of wood'.
posted by Brockles at 7:05 AM on September 21, 2007 [2 favorites]


I want to know how it handles when driven hard, at the limits of adhesion. It actually would have more total grip than a convention suspension, because it's allowing the unloaded tires -- inside tires in cornering or rear tires under braking -- to do more work. (Similar to why a stiffly spring car corners well or a rear-weight-biased car, e.g. Porsche 911, brakes well.) Hell, if they wanted, they could make the car lean INTO corners, like a motorcycle.

I suspect, however, that it'd be damn near impossible to control the Bose car at the limit with each corner continuously reconfiguring itself X times a second. Driving a car fast is all about managing weight transfer, and if the car is doing that itself, that'd be really hard to keep on top of. But who knows? The suspension can be anything at any time.

I can imagine sliding through a corner, car's understeering a bit so I back off the throttle a little to transfer weight forward... no, but WAIT, the front suspension has gotten "softer" to compensate by itself, so now I've way over-corrected and the tail is loose... countersteer... car tightens up the rear... DAMMIT snap spin!!

Give it to the guys at Grassroots Motorsports -- or at least Car & Driver, Automobile, whatever -- for some subjective feedback after a few hot laps around a race track.
posted by LordSludge at 7:18 AM on September 21, 2007 [1 favorite]


I can imagine sliding through a corner, car's understeering a bit so I back off the throttle a little to transfer weight forward... no, but WAIT, the front suspension has gotten "softer" to compensate by itself, so now I've way over-corrected and the tail is loose... countersteer... car tightens up the rear... DAMMIT snap spin!!

I had the same issue with the diff/power control on the Daft-powered Supra of 10 years ago, but driving fast is about getting the best from the car. In all aspects of driving you have to, at some point, just trust the car to sort itself out (you do so every time it goes over a bump, for instance). With the active diffs in Supras and Evos and the like, you just have to move your point of trust, keep your foot and the steering still and let the car do it...

After all, the system can react a damn sight faster than you can. It's just a scary thought.

Hell, if they wanted, they could make the car lean INTO corners, like a motorcycle.

The active F1 cars used to do that, but that is a whole new ballgame. Active suspension in road cars must be reactive with a slight lag I imagine. To lean a car into a corner and not know (the system can't predict) that the corner is actually a chicane rather than a simple right or left hander means it may be unbalanced for the next corner. Moving too far from equilibrium means a slower reaction time for the next required position. F1 cars could do this safely, because you know the corner radius and how long you have between them. They even used to drop down on the straights for aero drag reduction and then pop back up to dynamic ride heights for the slower corners...
posted by Brockles at 7:33 AM on September 21, 2007


Driving a car fast is all about managing weight transfer

Whilst I would fundamentally agree, you as a driver are doing it on a massively slower level of input than suspension is.
posted by Brockles at 7:35 AM on September 21, 2007


With all these technical advances in automotive engineering, how come it's so difficult to find a car that gets over 40mpg on the highway?

As recently as the 1980s, it was pretty easy. Now, your options are pretty limited.

I think the reason has to do with stuff like this. Advances in engine design allowed for more efficient engines, so in theory we should have lots of cars with fantastic mileage. But instead those same advances have been used to get more power, so instead we have cars with much higher power to weight ratios. So a 2007 Yaris won't get as much mileage as a 1985 Starlet, but it will outrun it six ways from Sunday.

As established, this won't have a significant impact on mileage, probably, but it's the attitude that it reveals that's telling: You've got to have MORE, all the time. More, more, more... that's why the Prius got so much heavier and doesn't get the kind of mileage it should: The thing had to have MORE. More power, mostly, but more luxury and features. I understand teh marketing thinking behind the decisions, and from a marketing standpoint I think they were right, but it still makes me sad.
posted by lodurr at 7:42 AM on September 21, 2007


Yes, pilot induced oscillations.

Naively, there is this notion of piloting/driving - I want to go here, along this path, at this speed - now just follow the line at arbitrary speed. The real task, on the other hand, involves many hours of practical experience learning about what the vehicle can do, and again practical experience learning how to design a track that challenges the limits of the car, and etc..

Reading about helicopter dynamics, I noticed a lot of discussion in the area of 'good handling characteristics'. Determining the mapping between mathematical representations of vehicle dynamics and driver/pilot opinion isn't simple when the environment and the tasks are simple. When you are trying to push the boundaries...
posted by Chuckles at 7:44 AM on September 21, 2007


lodurr, what you are saying sounds right enough, but for practical purposes, the dominant factor for highway driving efficiency is wind resistance, aka speed. Cut the speed and you improve the mileage. A lot.

Who knows what marketing departments are thinking when they draw up specifications, but when it comes to real world testing, I wonder if we've seen a subtle increase in tested speeds along with a subtle increase in actual highway speeds that I think have happened (not a driver - aren't I right in saying that US speed limits went down to 55mph in the 70s, and back up to 65mph at some point - then there are, or aren't, changes in actual highway speeds for average drivers).
posted by Chuckles at 7:55 AM on September 21, 2007


Advances in engine design allowed for more efficient engines, so in theory we should have lots of cars with fantastic mileage.

Don't forget that emissions requirements have massively increased in that time. Creating no emissions isn't necessarily a logical progression from burning less fuel (which is kind of odd, but true). Emissions stuff like Exhaust Gas Recirculation systems strangle engines.

Cars have needed to be more powerful for marketing as well as practical reasons. As cars get more luxurious and convenient (air con, better seats, heavy sound proofing and glass) more power is required to push them along. And a bit more than the necessary increase sells, innit?
posted by Brockles at 7:55 AM on September 21, 2007


Cars have needed to be more powerful for marketing as well as practical reasons.

The marketing reasons were precisely my point.

Cars today are much more powerful. Yes, some of that probably has to do increased weight. But don't just look at the horsepower: Look at the acceleration numbers. Cars are just much quicker than they were 10 or 20 years ago.

That's marketing, not "need."

Do I expect auto manufacturers to make grim econoboxes with no features that plug along like a 2cv6? Of course not. I'm just pointing out the trends, and saying they make me sad.

Oh, and regarding weight and features versus mileage: Of the small, light Honda FiT or the slightly larger, more up-market Civic, which do you think gets better highway mileage?

That's right: The bigger and heavier Civic.

Again, I think I understand why in the larger sense (I think it's because the parts that make the Civic more efficient also make the unit cost higher, so Honda is preserving its margin), and it didn't stop me from buying a FiT. But it does indicate that you can get good mileage if you want it. Put that drivetrain in a FiT, and you'd probably crack 40 on the highway no sweat.
posted by lodurr at 8:08 AM on September 21, 2007


What Woodblock100 and Tommasz said.

My immediate reaction is to say that no urban centre should allow a vehicle with this kind of suspension within their downtown core.

I'm serious.
posted by poweredbybeard at 8:32 AM on September 21, 2007


It pisses me off to no end that F1 has to ban these awesome technologies. ABS, Traction control, active suspension, all banned or restricted to reduce cornering speeds. Hell even the tires are de-rated to avoid killing drivers.

After the next DARPA Grand Challenge, I'd be surprised if nobody starts a robotic racing league. Automated control, the only limits you have are an intake restriction and a weight floor, everything else is fair game. How fast can car makers make a car go around a track when they don't have to worry about politics and driver safety? Hell, even add a "simulated human load" like the initial SS1 launches to simulate a passenger carrying vehicle.

VW is already doing similar things with a robotically controlled Golf GTI. When you can program and repeat a given maneuver infinitely, development becomes a lot easier. You can remove human imperfection from the testing process and test just the car.

That video lies a bit, the robot-driven car isn't substantially faster than even a mediocre driver, but it's perfectly consistent.
posted by Skorgu at 8:37 AM on September 21, 2007 [1 favorite]


That's a bit witch burning, isn't it?

So you want to ban any car that can't have its speed forcibly controlled by speed bumps from a potentially speed bump 'controlled' area?

Despite the fact that it is only passenger comfort that actually makes speed bumps any kind of deterrent at all (up to about 15-20mph above the limit when potential damage occurs) and that between the bumps there is no means of controlling speed?

The idea that speed bumps and their archaic inefficiency and pollution-adding 'control' methods should be the presiding factor for vehicle development and/or access to urban areas smacks of caveman engineering and using hammers to fix a problem because a decent/cost effective one can't be found. I hope no-one in legislation feels like you and sees new technology in a similarly blinkered way...
posted by Brockles at 8:39 AM on September 21, 2007


Lodurr has a point that I've been thinking about: new cars are pigs. And most people don't realize it. Quick, which weighs more: a 2007 Camry or 1955 Chevy? Every '55 chevy model, including the station wagon, weighs less than the xle camry. The lightest chevy model (the one I have, a utility sedan) weighs 200 lbs. less than the lightest camry. And this is in spite of the fact that the chevy has no aluminum or plastic components.
posted by 445supermag at 8:40 AM on September 21, 2007


Hey guys i think your all forgetting a major factor why cars are getting fatter and heavier.

SAFETY!!!

Check this video out, a small modern hatchback against a mid 90s volvo 940, quite a large beastie stationwagon.

I dont want to give too much away so go watch it and come to your own conclusions about vehicles getting heavier due just to marketing gimmicks.
posted by ItsaMario at 8:40 AM on September 21, 2007 [2 favorites]


Of the small, light Honda FiT or the slightly larger, more up-market Civic, which do you think gets better highway mileage?

According to the EPA, it's the Fit that does (slightly) better (2007 models). I assume you're thinking of the hybrid Civic, which is considerably more efficient for double the price. Calling the Fit smaller is a bit misleading too; although it's lighter and more compact, it does have rather more interior volume than the Civic coupe. Which is exactly why, because of the aerodynamics, it doesn't have more of an advantage in fuel efficiency. Yeah, I bought one too.

Speaking of which, I'm surprised that the active suspension uses more power than it saves on a bumpy road. You'd think moving the wheels takes a whole lot less energy than bouncing the whole car up and down.
posted by sfenders at 8:56 AM on September 21, 2007


Hey guys i think your all forgetting a major factor why cars are getting fatter and heavier.

SAFETY!!!


A full roll cage like race cars have weighs only 100-200 lbs. (and only costs a couple hundred dollars retail).
posted by 445supermag at 8:56 AM on September 21, 2007


Roll cages are only half the story. You have crash helmets on, full 6 point belts and proper, bolted in seats. And children aren't allowed to get in competition cars.

Crash safety is about road cars is about crumple zones and reducing the peak g-loading in the impact. This is absorbed by the car so that the occupants experience as little of it as possible. In competition cars, the seats and belts and helmet do a lot of the work (HANS devices etc) that lack of crumple zone create. Any low speed crash in a roll cage car (ie much stiffer) means that more of the crash impulse gets transmitted to the occupants. It doesn't make it safer, just shifts the speed that the crumpling is effective in to a much higher level.
posted by Brockles at 9:11 AM on September 21, 2007


Im sure a full roll cage is a practical option for the majority of people who use a car to get to A to B in a practical manner.

I can just see 60 year old menopausal women climbing through a maze of metal tubing to access the drivers seat.

while were at it how bout we make 3 point safety harness, flame retardant overalls and a helmet standard too, so your 2 minute trip up to the shops to buy milk at midnight will take u half an hour once you have climbed into your car and strapped yourself in tight and made sure you spent time getting into the appropriate clothing.

If only it were as easy as fitting a roll cage into every road going car then surely it would have be done already. A lot of time, money and effort goes into making small cars safe so somehow i don't think automotive engineers have decided to overlook such a solution for a road going vehicle.
posted by ItsaMario at 9:17 AM on September 21, 2007


ahhh brockles you beat me to it...
posted by ItsaMario at 9:19 AM on September 21, 2007


What people are perhaps totally missing is that roll cages are just additional structure with no respect to aesthetics. The car itself is already a structure and strengthening it with invisible (to the naked eye) internal gussets and material thickness (while still retaining aesthetic and practical elements) is exactly the same as adding a roll cage.
posted by Brockles at 9:20 AM on September 21, 2007


Itsamario: I TYPE LIKE TEH WIIIIND!
posted by Brockles at 9:20 AM on September 21, 2007


Golf clap for you sir...

*ques music*
posted by ItsaMario at 9:25 AM on September 21, 2007


According to the EPA, it's the Fit that does (slightly) better (2007 models). I assume you're thinking of the hybrid Civic...

No, I was thinking of the numbers on the window sticker at the dealer. As I recall, according to that sticker, the Civic was EPA rated at about 5MPG better on highway. The sales guys were well acquainted with the difference and had accommodating patter.
posted by lodurr at 9:28 AM on September 21, 2007



Im sure a full roll cage is a practical option for the majority of people who use a car to get to A to B in a practical manner.

My point was that even over the top safety only weighs a couple hundred pounds. Go to a junkyard and look inside a modern car, in stead of a tube across the door like a roll cage, they have a corrogated strip of metal inside the door that serves the same purpose, but doesn't weigh more.
Crumple zones are weakening in specific spots, again doesn't cause extra weight.
posted by 445supermag at 9:29 AM on September 21, 2007


Um, if you're not wearing a helmet, having a roll cage is more dangerous than having none.

Most traffic fatalities are due to head injuries. One day, Sweden (just a guess) will enact a mandatory motorist helmet law, Americans will laugh at them, but then they'll cut traffic deaths by 80%. Then Americans will start wearing them.

After spending a weekend sliding through corners in a race car at 100+mph, but in full safety gear, I feel downright naked and vulnerable stepping into a street car.
posted by LordSludge at 9:31 AM on September 21, 2007


Um, if you're not wearing a helmet, having a roll cage is more dangerous than having none.

(plus all the rest of it), but yes.

A roll cage adds strength. It doesn't necessarily add safety. Safety comes from crumple zones and reducing the g-spike of the accident and any intrusion into the passenger cell.
posted by Brockles at 9:36 AM on September 21, 2007


btw brockles that was an appreciative golf clap i meant to give before.

anyone here know if roll cages would be any good in an offset accident where energy is directed at its weaker points such as joints?
posted by ItsaMario at 9:43 AM on September 21, 2007


No, I was thinking of the numbers on the window sticker at the dealer.

Sorry, I didn't look closely enough. Strangely, it seems there's a bigger difference with the automatic transmission, and the manual versions have the same number.

The jump at the end is a gimmick.

Yeah, but it's a more appealing gimmick that some of the crap that sells, like in-car DVD players. You know someone's eventually going to be using this technology to put a big red "jump" button on the dashboard, the market will demand it.
posted by sfenders at 10:28 AM on September 21, 2007


ItsaMario, was that video supposed to show that heavier cars are safer? Because it showed a smaller car with modern safety features kicking the crap out of a bigger, older car.

About 10 years ago I saw a video of a head-on crash between a Smart car and a big Mercedes sedan. The Smart did a 480 degree pirouette and had its front end completely obliterated, but the cabin was intact and airbags deployed all around, and the dummies showed only minor injuries.

OT, I swear I saw a demonstration exactly like this about 15 years ago. At the end, they had the car climb stairs.
posted by bjrubble at 10:29 AM on September 21, 2007


bjrbubble: It was supposed to show that a small car becoming heavier has allowed it to compete (in terms of safety) with a much heavier one. Showing that 'biggest car wins' (as always used to be the case) only works if they are of the same era.

Technological advances are better than just using mass to help you out in a crash, but these have a weight penalty for any given size of car.
posted by Brockles at 10:35 AM on September 21, 2007


anyone here know if roll cages would be any good in an offset accident where energy is directed at its weaker points such as joints?

They'll prevent injury by cabin intrusion, but they (generally) do nothing to dissipate impact energy or to prevent the secondary impact of the occupants with the car's interior. For that, you need a 5-point harness, helmet, and HANS device.
posted by LordSludge at 10:45 AM on September 21, 2007


anyone here know if roll cages would be any good in an offset accident where energy is directed at its weaker points such as joints?


You need to define 'good'. They'll be great in a crash for maintaining the integrity of the safety cell, just not so hot on reducing crash force impulse. A properly welded and fitted cage will rarely fail at the joints, they are usually stronger than the individual tubes (through gusseting and the size of the joins).
posted by Brockles at 11:01 AM on September 21, 2007


I'm disappointed that the jump is a gimmick. I had visions of a pro-active suspension with forward looking radar.

Whilst I would fundamentally agree, you as a driver are doing it on a massively slower level of input than suspension is.

No, a driver can anticipate with forward vision + experience upcoming turns and bumps and compensate ahead of time. For example, one can shift the weight briefly onto the front axle by tapping the brakes before a turn. One can even ameliorate the discomfort of hitting a speed bump at speed by tapping brakes then accelerator early enough so that the bump is hit just as the front bumper comes up from its dip.
posted by BrotherCaine at 1:47 PM on September 21, 2007


Why did the car in the linked video leap over the 2x6, anyway? How did it know it was coming? Does it have a sensor, or did the driver have to do something manual (press "Turbo Boost," maybe?) to make it do that?

I don't speak French, so I couldn't understand the guy's explanation.
posted by ikkyu2 at 3:03 PM on September 21, 2007


Nothing so complicated ikkyu2, the suspension system has an irrational fear of 2x6 lumber and will do everything in it's power to not have to touch it.
posted by quin at 3:10 PM on September 21, 2007 [1 favorite]


No, a driver can anticipate with forward vision + experience upcoming turns and bumps and compensate ahead of time.

You misunderstand my point. Doing it earlier doesn't make your input faster, just earlier. I was referring to the speed of input/output feedback loop. A computer is a teensy bit faster in reacting to inputs (ie bumps) than you are. Avoiding the bump doesn't make your reactions any quicker...

How did it know it was coming? Does it have a sensor, or did the driver have to do something manual (press "Turbo Boost," maybe?) to make it do that?

The car 'jumped' as part of (I am guessing) a pre-programmed demo to show exactly how much the system can affect the car. They just put the plank in the right place and timed the leap. The car in no way reacted to the plank.
posted by Brockles at 4:32 PM on September 21, 2007


Brockles, technology moves on. If you would bypass the EGR system on a modern car, you would actually lose power.

Not to mention the management system on your direct injection petrol engine which would throw a fit.
posted by Djinh at 5:05 PM on September 21, 2007


Dinjh: Only and purely because the ECU is mapped to account for it being there. So the carefully controlled mixture gets all kinds of screwed up if you remove or change parameters without telling the 'brain'. It is a closed system. If you unplug the water temp sensor, you'll lose power, too. Or the Air flow meter. You are changing a system in a way that the ECU cannot compensate for.

Not one single racing engine has EGR. It is not in any way a power help, it is purely for emissions and technology is relevant in that it has allowed EGR to be incorporated whilst decreasing the overall power loss impact of having to do so.
posted by Brockles at 5:36 PM on September 21, 2007


... as part of (I am guessing) a pre-programmed demo ...

In the final shot, it looked to me as though the presenter has a remote control that he uses to cue the car's "bow". I expect they rigged it up to do tricks just like that at dog and pony shows. So the "turbo boost" explanation is, I expect, substantially correct: The driver pressed a button on the remote labeled "jump" at a carefully marked point on the course.

After watching, it occurs to me how much a system like this could do if it actually did have reactive characteristics. If Bose is smart, they'll sponsor a DARPA Grand Challenge car and do something clever with it...

As for human-triggered use: The possibilities for lowriders are endless....
posted by lodurr at 4:02 AM on September 22, 2007


anthill, while I agree with you, wasn't this a very similar argument that fighter pilots made when they started using computers to control flight (and fighters are now so non-naturally flyers they need a computer to keep it airborne)?

Trust me, the pilots feel connected to the aircraft dynamics. The argument was losing the direct mechanical links to the surfaces and therefore direct control of the aircraft. Trusting your life to the supplier with the lowest-cost solution for the flight control software can be unnerving.
posted by Doohickie at 9:08 AM on September 22, 2007


I'm afraid this whole discussion is going rather awry. People are mistaking the general concept of active suspension with Bose's particular electromagnetic active suspension.

Active suspension is not new at all. Very expensive cars (Maybachs, Rolls-Royces, top-level Bimmers and Mercs, Maseratis, etc.) have been featuring active pneumatic suspensions for a while now. Citro├źn has had hydropneumatic active suspension in its top-end models since the mid-90s (the original 50s hydropneumatic suspension was nifty, but not actively controlled). What all these active suspensions have in common is that a microprocessor actively pilots the stiffness and damping characteristics of the suspension for a better ride. In this they are indeed similar to fly-by-wire systems in aircraft.

The reason why current active suspension systems are so expensive is that in this happens through expensive and delicate precision electrovalves letting fluid in and out the hydraulic and pneumatic elements.

The solution, of course, would be to substitute the hydraulic or pneumatic actuators with direct electromagnetic actuators like those developed by Bose. The trouble is that such actuators can't match so far the reaction times of hydraulic/pneumatic actuators at those force levels.

In aircraft there is very much the same problem: plane makers would love to get rid of those heavy, expensive and failure-prone hydraulics for the flight controls, but they haven't been able so far to find adequate electromagnetic actuators that are both strong and quick.

That's why the jump in the Bose demonstration is significant...
posted by Skeptic at 12:34 PM on September 23, 2007


I guess I don't get it, then: The jump, as shown, isn't that quick. It seems to me that the rumble-strip test is a much better one to illustrate that property.
posted by lodurr at 2:58 AM on September 24, 2007


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