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Efficiency? Think Racing Cars, Not Hybrids
Gordonjcp writes "A renowned racing car designer has said that car manufacturers should be looking at making cars lighter to improve efficiency, rather than adding complex drive trains. In this article on the BBC News website, Professor Gordon Murray explains that a weight saving of 10% in a normal car would make more difference than switching to a hybrid engine and motor combination. Could this be the next nail in the SUV's coffin?"
Cars need to be lighter and more aerodynamic. The drag on a standard automobile is just ridiculous. Rear ends today are typically vertically flat! Who are these designers that aren't familiar with the teardrop shape?
Developers: We can use your help.
Lighter SUVs flip over easier. How could you prefer any SUV when it's far less safe? Minivans and station wagons at least have better crumple zones to protect you in a crash. Even those half-SUV/half-car things use car frames with proper crumple zones and have a lower center of gravity.
Developers: We can use your help.
Safety devices in cars are the major reason that fuel efficiency hasn't significantly improved since the 70s. Since the 70s and 80s up to 500 kg have been added to cars in the form of safety devices. For example, a 1979 Honda Civic had a curb weight of 680 kg. A 2008 Honda Civic has a curb weight of 1180 kg. A 1980 Toyota Camry had a curb weight of 1000 kg. A 2008 Toyota Camry has a curb weight of about 1500 kg. This 500 kg rule applies across a broad range of vehicles.
The original Lotus Elise got almost 30 mpg with 1.8l, 120 hp, and it was a high-performance car.
Put a little 1 liter, 60 horsepower engine in there and it'll probably get 50 mpg, but have regular car performance.
The secret? Weighing only about 1,650 lbs.
Because basically a long time ago, someone discovered that you can cut off the tail of that teardrop, and the air flow will still be largely the same. Only this time without the added mass and drag of that teardrop tail.
And especially if you read the RTFA, weight is a big problem. Increasing the car's weight with a useless tail would negate any aerodynamic benefits anyway. If you save, say, 0.5 litre per 100 km in aerodynamic drag with a tail, but pay 1 litre per 100 km to move that extra weight, it's not worth it.
A polar bear is a cartesian bear after a coordinate transform.
I don't know about most American cities, but where I live gas would have to be $10 a gallon for years before it would be concievable to move close enough to work to walk or ride a bicycle. American cities are failing to provide the infrastructure to do anything like that and the few people who might be interested are far outweighed by the majority. Further, companies are more than willing to send their employees to other locations ad hoc with little regard to their personal needs. I was once next to a man on a plane who took an 8 hour flight to work every monday and flew back every friday because his was a specialized field and the company wanted him to work somewhere far from home.
A truncated teardrop with a flat back (like the Prius or the Insight) is actually more aerodynamic than the teardrop. It's called a Kammback, and it's named for the gentleman who noticed that if you chop off the back of the teardrop, the air keeps flowing the same way, except without the drag of sliding along the surface of the parts of the teardrop you just chopped off.
A good example of this is an F1 car - they are designed with crashes in mind. They have strong central component to protect the driver with everything else breakable to take energy away from the tub that the driver sits in. Take Robert Kubica's accident in the 2007 Canadian Grand Prix, for example, After contact with Jarno Trulli, his car hit a bump, lifting it and rendering him unable to steer. His car hit a safety wall at approximately 28G decelaration and then tumbled down the track, finally coming to rest against another safety wall on its side. Most of car was strewn along the track, but the tub protected the driver. He not only lived to race again, but suffered little injury.
Noted, these are very, very expensive cars, are single seaters, don't have doors (making the carbon-fiber tub that the driver sits in much easier) and not really designed to run on the street, but the concept of sheddable body around a strong central area still could apply
Of course this makes the car more costly to fix which will annoy insurers and leaves a nasty very sharp mess on the street if you use the baked carbon fiber that they use on F1 cars, but if you want to make cars lighter and still protect the driver and passengers, it's worth looking at...
Amory Lovins, in his excellent TED Talk on Winning the Oil Endgame, makes an argument that weight savings need not lead to descreased safety. An example that he cites is a hand-built McLaren that has a couple of woven carbon-composite cones in the front that absorb the energy of a crash. Well worth a listen.
The "cue the foo posts in 3, 2, 1..." posts will commence with no subsequent foo posts in 3, 2, 1...
Unfortunately it's not a myth, and it wasn't created by marketing.
The crash compatibility topic (big car vs. small car) was first brought up by the Insurance Institute for Highway Safety in a 1998 news release that stated:
The basic findings reinforce whatâ(TM)s long been known about vehicle size and occupant death rates. As vehicle weight decreases, the number of occupants killed in crashes increases.
and
Lighter vehicles have higher occupant death rates in two-vehicle crashes, and within each weight class, cars and pickups have similar occupant death rates.
Here is the link http://www.iihs.org/news/1998/iihs_news_021098.pdf
These comments are my own and do not necessarily reflect the views or opinions of my employer or colleagues...
Worth mentioning.... the aforementioned McLaren was designed by Gordon Murray... the author of the article. He's also been a very successful designer in Formula One.
And of course you're inferring a causal relation from a correlation. None of those quoted statements take into account specific circumstances. Do people speed more in smaller cars than in large SUVs, thus leading to more accidents? Are people more likely to switch lanes more quickly in smaller cars than in large ones? Smaller cars also accelerate faster than SUVs, so at intersections the small cars will be the first into the intersection after a light turns green. None of these things are taken into account.
Gas prices increasing to the point where driving a light, efficient car is the only option is not going to happen you say? I beg to differ. Here in The Netherlands, it's already happening. There has been an extreme increase in gas pricing the past year. You now pay E 1.65 per liter, which is about $ 9.21 per gallon. Yes, you read that right. For a full tank in a small to medium sized car (40 liters), you easily spend over 60 euros. That's $ 100 for a tank of gasoline.
Over here, even in the rich suburbs people are selling their SUV's and buying small cars like Mini's and Fiat Panda's. The number of SUVs sold is dropping rapidly. It was recently in the news that last year, the amount of SUV's sold was only 1/5 of the year before that.
Pretty good is actually pretty bad.
No. Diesel is popular in Europe because it gets better mileage. Every company and their brother has a diesel vehicle in Europe, if you don't you're SOL in the market. Manual transmission too.
I have a 1998 Jetta VW that can haul 4-5 people. A weekend of luggage and still get 45 MPG. Even with diesel pushing $5/gallon it's still cheaper per mile than any gasser OF THE SAME SIZE.
"Heavier Diesel". You talk about it like it adds 2 tons to the vehicle. A diesel engine may add a few hundred pounds at most.
VW has a PRODUCTION car that they sold that got 78 miles per US gallon. There is nothing more frustrating than hearing about the 'amazing' 30 MPG that some small cars get while in Europe they're doing double that.
SUV are much, much worse at avoiding collisions, and are more likely to be involved in accidents per driver miles.
..........FULL STOP.
The crash statistics alone indicate that feeling safer in an SUV is a false sense of security. Could have something to do with many soccer moms not being able to see over the dashboard. That and the tendency to roll over when driven like a sports car.
Mod parent up! Not only is the 12-year-old McLaren F1 still one of the quickest and fastest cars ever built, it does it without resorting to 4 turbos and 1,001 horsepower simply by being lighter.
Not only that, but Murray also worked to finalize the design of the (already nearly complete) Caparo T1, which is even quicker (0-60 in 2.5 seconds), and with less horsepower than the F1. How? It weighs about half a ton.
The difference between spam and poop is that you don't have to dig through septic tanks looking for real food. -- Me
I remember a lecture from one of my profs who used to work with the NTSB. He mentioned crash fatality studies where moving from a car-car collision to a car-suv collision made little change on the probability of death to the SUV driver, but significantly increased the probability of death to the car driver. thus, according to that metric, the bigger vehicle only serves to increase the other person's chance of dying without making you any safer.
Current hybrids include storage batteries that weigh a lot. They can be replaced with a much lighter flywheel that also has a higher efficiency than batteries, at storing and releasing energy (and also works with regenerative braking). Do not confuse this with other decades-old ideas of using flywheels to fully replace the car engine; we cannot make them strong enough to hold energy for 300 miles of travel. But we can easily make them able to hold enough energy for a few bursts of rapid acceleration. The only reason a smallish car has a 100HP engine is to get rapid acceleration. Any hybrid can replace that with a much lighter 15-20HP engine, which produces plenty for cruising at a fixed speed, plus some extra to charge up the storage unit for the desired rapid acceleration. A hybrid that uses a flywheel might weigh about the same as the ordinary car, but it will get better gas mileage because of the smaller engine.
Cyclists should be riding on the sidewalks. The relative momentums of bike riders and pedestrians are much closer than bike riders and multi-ton vehicles. The traffic laws for bicycles seems to hearken back to the days when an automobile's average speed was 15mph.
In case anyone actually believes this: http://en.wikipedia.org/wiki/Waterpowered_car Sorry to spoil your fun.
-Xoltri
On a real track or road, with full aerodynamic gear, an F1 car would smoke the Bugatti. For an idea of what an F1 can do, see this comparison of Formula 1 Car vs Ferrari 550 Maranello vs Fiat road car.
"When I first heard Daydream Nation it quite frankly scared the living shit out of me." -- Matthew Stearns
You do realize that all the "entry level" cars, such as the Hyundai Elantra, Toyota Corolla, Honda Civic, etc. all come with manual transmissions standard, right? On all these cars, getting an automatic transmission is an option that adds to the cost of the car.
We all know what to do, but we don't know how to get re-elected once we have done it
When was the last time you bought a car? I bought my '07 Hyundai Elantra last year, and I can tell you that there were at least as many manual on the lot as there were automatics. I shopped Toyota Corollas and Honda Civics too (not as extensively), and they too had plenty of manuals on the lots.
As for incentive packages, I don't think I've ever seen an incentive package for one of these cars that said "You have to get the automatic version", in the fine print.
We all know what to do, but we don't know how to get re-elected once we have done it
My Geo Metro has a 51Hp engine, gets 50 MPG, and cruses at 75 MPG on the highway. I live at 9000 ft elevation and commute down a mountain to 4500 at steep grades. It goes as fast as you'd want to on mountain roads with 3-4 passengers. Yes its no drag racer, but it goes from pt. A to B efficiently and reliably. Besides it cost me 1/10th of a hybrid and gets the same milage. We love it.
Now imagine making it lighter and hybrid. No Doubt 20 Hp is sufficient.