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?"

In the US no one wants to buy light cars

Because they're afraid they'll be crushed to a fine pulp when they get hit by a big honking SUV.

Re:In the US no one wants to buy light cars

And their fears aren't exactly unfounded. Only way to get the majority of people to stop driving heavy cars is to increase gas prices to the point where lighter cars are the only option, or having a flag day where everybody agrees to switch, i.e. not gonna happen in the near future :)

Re:In the US no one wants to buy light cars

Amory Lovins, in his excellent TED Talk on Winning the Oil Endgame [ted.com], 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.

Re:In the US no one wants to buy light cars

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.

Re:In the US no one wants to buy light cars

Not necessarily, if you design the cars in the right way - with a strong inner shell and everything else disposable.

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...

Re:In the US no one wants to buy light cars

Because with greater vehicular mass should come greater driver responsibility.

Re:In the US no one wants to buy light cars

It seems to me that there's got to be a reason that pedestrians have the right of way. Maybe it's that in exchange for being granted the privilege of driving an automobile on a public road these drivers assume responsibility for remaining in control of their vehicles and are accountable for the consequences of failing to do so.

You get in a Mazda Miata, drive off the road at 30mph, you run through a mailbox and crash into a light pole. You do the same thing in a Ford Excursion at 30mph, you go through the mailbox, pole, the two kids in their plastic wading pool, grandma whose watching them from a lawn chair, and crash in to the house, maiming mom and dad who were watching tv sitting against the wall you just drove through.

Bigger car = more potential for harming others.

Re:In the US no one wants to buy light cars

I bike commute to work, the only close shave I've had is with a school bus. But then again we are both speaking with anecdotal evidence.

Re:I am also an avid cyclist...

I bike commute to work, and the only close shave I've had is with the new Gillette Fusion(r) Power razor. Truly, the best a man can get.

Re:In the US no one wants to buy light cars

I used to bike commute, and my only wreck was with a tow truck. But it was my own stupid fault, not his, and if you're going to go over your handlebars, I highly recommend doing it onto the flatbed part of a flatbed tow truck. Saves the long fall back to the pavement.

Re:In the US no one wants to buy light cars

The flaw in your argument is that these days almost NOBODY gives a flying fuck about anyone but themselves. It's not restricted to SUV owners.

Re:In the US no one wants to buy light cars

Sadly you can remove "these days" from that claim. Your point would still be accurate and as a bonus it wouldn't come out as "Get of my lawn!".

Re:In the US no one wants to buy light cars

As an avid motorcyclist, i can say that a large majority of the time I've been nearly turned to a small spot on the road is due to morons driving cars who are on cell phones.

These morons (or cagers as we motorcyclists car eto call them) come in all shapes and sizes and so do their vehicles.

in fact i can provide anectodatal evidence of everythign from a fucking little college girl who ran a buddy off the road while merging off an off ramp, to the time a farmer pulled his combine onto the road directly in front of a group of 20 bikes.

None of that means a shit to anybody but the people who were there, yet i can say that i'd much rather we prosecute idiots who arent paying attention than go after a specific type of vehicle.

FYI, this isnt exactly a new situation for motorcyclists. We've been complaining about this longer than SUV's have been a mainstream vehicle.

How about instead of trying to lump people by the type of vehicle, we instead start issuing "distracted driver" tickets to all those morons deserving of them.

I'm fairly certain every state in the union has a distracted driving law on the books.

Re:Why the safety assumption?

The SUV safety myth was created by marketing pure and simple.

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 [iihs.org]

It's a question of weight ratios

... but how many coconuts can an SUV carry?

Re:It's a question of weight ratios

American or Japanese?

What about 10% weight savings in the driver's seat

I'm just saying...

It might be helpful.

Surprising

So aerodynamics and weight make a difference when trying to propel an object?!

This is going to revolutionize everything!

Maybe if we drove cars in space we wouldn't have those pesky problems.

Who knew?

Lighter cars use less gas? What's next? Telling people that they shouldn't live 200 miles from where they work? I heard a kind of a funny fact this morning on BBC, average energy consumption per capita in North America is double that in Europe. It's not like the standard of living or climate is that much different, it's all about the culture.

Lotus Elise

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.

Regenerative Brakes

Hybrids get their benefits in two ways: reclaiming power that would otherwise be lost during braking, and the fact that electric motors have a flat torque band. You generally can't do either that with an internal combustion engine alone.

However, there are a few ways to do both the above without an electric motor. One way is to have a flywheel connected to a CVT on the drive shaft. When you hit the brakes, the flywheel spins up. You can then release that power again when you accelerate. The flywheel will also act as a gyroscope, so you need to have some way of tilting it so you can go through corners with it spun up (which has the side effect of increasing handling). This method is being put on F1 cars soon.

The other way is to have an air compressor, which again is run off the drive shaft when you hit the brakes. On acceleration, the compressed air could either run the drive shaft, be dumped into the intake to increase boost, or dumped into the exhaust manifold to eliminate turbo lag. This is probably easier to design than a tilting-flywheel system, though it won't make handling better.

The compressor could also run off turbines using inlets around the car's body that are opened when braking. This particular use is probably illegal for F1 and other types of race cars (which often ban variable body shape systems), but could easily be used in road cars.

Both the above don't require any particularly exotic materials (though carbon fiber or nanotubes would be nice for the flywheel), and shouldn't be as heavy as an electric motor/battery system.

Re:Two things

Cars need to be lighter and more aerodynamic [aptera.com]. 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?

Well, the teardrop shape is less space efficient than a box, and most vehicles don't go fast enough often enough to make use of quality aerodynamics. If it's just a mom driving her kids to school, and around town, she's rarely going to get over 35mph and likely not waste much fuel in wind resistance. But the fact the vehicle is boxy means she can get more kids / stuff in the back end and much easier. To have the same space but a slopey backend would required adding several feet to the overall length of the vehicle.

Kammback

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 [wikipedia.org], 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.

Re:Partially right...

I like being able to see OVER traffic.

This amuses me to no end, and I've heard it repeated from people at the Budget rental place as well as talking heads on TV. What possible use is seeing over traffic if you're still stuck in it? Are you following too closely and not paying attention to your surroundings or something?

Re:Partially right...

Most people drive SUVs because they like the way they look, and then they rationalize it by coming up with other reasons.

Most smaller cars have a lot more head and foot room, especially for the driver, than you give them credit for. I'm 6'2" and drive a 2001 Toyota Corolla. I have plenty of head room without slouching over or anything, and leg room is not an issue either. Heck, I have two kids and they fit just fine in the back seat of the thing, so the hauling kids excuse is silly too unless you happen to have 5 kids or more. It makes me crazy when people with 2 kids say they need an SUV to "haul the family around".

As for seeing over traffic, I have no problem seeing the traffic ahead of me so long as I keep a safe distance between me and the person in front of me (2 second rule, remember?), and have only even been close to having an accident (which I was able to maneuver to avoid) once in my 15 years of driving.

The hauling stuff excuse may be valid for some people, but you have to ask yourself how often do you really need to haul around so much stuff that you require an SUV. Most people haul stuff like that so rarely it would be far more cost effective to simply rent a pickup truck when they need to do that rather than spend all that money on the SUV full-time. Even small cars like mine can fit a surprisingly large amount of stuff in them.

I wish people would just admit that they really wanted an SUV, so they came up with reasons why they should get one, rather than insisting that no other type of car could possibly work for them.