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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?"
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?
It doesn't mean much now, it's built for the future.
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.
Not a typewriter
I did a UI course back in 2002 and we happened to be talking about steering wheels as the UI input device. The prof happened to be a Psychology/Comp. Sci. cross, and he went off on a tangent wrt a certain thought experiment:
The hypothesis says: the higher the chance of death, the lower your speed. If the chance of death in a moving car were 100%, no one would drive. If the chance of death were 0, then everyone would drive as fast as the car could go.
What happens if you put a spear sticking out of the steering wheel aimed at your chest?
Odd - slashdot managed to eat my post during preview.
In any case, here's the equation you want: E=0.5m*v^2. Know that the weight of a Miata is 940 Kg and that of an excursion is 3261kg. For the Miata to have the same kinetic energy as the Excursion at 30 mph, the Miata has to drive at 55 mph.
Who is the idiot who is driving 55 in a 30 mph zone?
Those who can, do. Those who can't, sue.
I work in London, UK. Gas is $10 a gallon.
Our public transport is OK, not great, but it costs $15/day and takes 45 mins on the train, compared with $35 fuel, $15 congestion charge and $25 parking to drive - for 1 hour 50 mins.
(And the housing beyond insane - you could not buy a home of any sort for less than $1 million within 30 miles of my office)
You will get this eventually in your big US cities. LA is the size of London, and starting to run of space to build 10 lane highways. New York is probably already like it.
"Those who cast the votes decide nothing; those who count the votes decide everything." (attrib. Joseph Stalin)
This is the reason flywheel energy storage is not used in vehicles. The flywheels turn at super-high rpms, amplifying this issue. AFS Trinity (formerly American Flywheel Systems, I think...) worked on the AFS-20 as a prototype flywheel car back in the mid 90s. They never got it working. The problem is that when you are driving, and you turn, precession causes a large amount of friction against your flywheel bearings as it resists the turn.
Last I heard, they were working on magnetic bearings, instead of physical ones, but there's been little progress released to the public so far.
The main advantage of a flywheel is that it can handle rapid charge / discharge, but ultracapacitors are another way to gain that benefit without the disadvantages of flywheels.