Unrepentant Geek (matthew) wrote,
Unrepentant Geek

Thoughts on vehicles and effeciency

I've been watching a good bit of Top Gear lately. It's an amusing show and I do like cars and whatnot but something has started to nag at me. All of the cars they showcase from 50 mpg economy cars to super-cars that get as little as 2 miles per gallon are all insanely wasteful of the energy we put into them. Even the Prius only manages to make slightly better use of the wasted energy. We are driving around thinking that we are doing great at 50mpg when all we are really doing ultimately is converting fossil fuels into waste heat. We even have specialized systems on the vehicles to cool the engine and the brakes where we 'generate' it all.

I'm tired of it.

I want a car that is efficient. I'm not talking about 50 mpg. I'm not talking about 100 mpg. I'm talking about a car that uses only as much energy as is required to change my altitude from origin point to destination plus a bit to deal with friction.

Robert Heinlein made an astute observation about technology in his novel The Rolling Stones:

Every technology goes through three stages: first a crudely simple and quite unsatisfactory gadget; second, an enormously complicated group of gadgets designed to overcome the short comings of the original and achieving thereby somewhat satisfactory performance through extremely complex compromise; third, a final proper design therefrom.

This three stage theory applies itself well to a large number of technological fields. Unfortunately for many we're still stuck at stage two. Look at space flight. The shuttle is an amazingly complex piece of equipment. I think that for computers and communication we are actually making our way into stage three. Sure, a computer is a frighteningly complex machine, but we are constantly simplifying the user interface.

The one place that we're solidly stuck at phase two is cars. In fact, we just keep pushing the level of complexity further and further. Heinlein described the internal combustion engine thusly:

These unbelievable museum pieces were for their time fast, sleek and powerful--but inside their skins were assembled a preposterous collection of mechanical buffoonery. The prime mover for such a
juggernaut might have rested in one's lap; the rest of the mad assembly consisted of afterthoughts intended to correct the uncorrectable, to repair the original basic mistake in design--for automobiles and even the early aeroplanes were "powered" (if one may call it that) by "reciprocating engines."

A reciprocating engine was a collection of miniature heat engines using (in a basically inefficient cycle) a small percentage of an exothermic chemical reaction, a reaction which was started and stopped every split second. Much of the heat was intentionally thrown away into a "water jacket" or "cooling system," then wasted into the atmosphere through a heat exchanger.

What little was left caused blocks of metal to thump foolishly back-and-forth (hence the name "reciprocating") and thence through a linkage to cause a shaft and flywheel to spin around. The flywheel (believe it if you can) had no gyroscopic function; it was used to store kinetic energy in a futile attempt to cover up the sins of
reciprocation. The shaft at long last caused the wheels to turn and thereby propelled this pile of junk over the countryside.

This was published in 1952. In the intervening 57 years we have just continued to refine this design further. A modern car still has lumps of metal thumping back and forth and dumps all that energy as wasted heat. Heinlein continues:

The prime mover was used only to and to overcome "friction"--a concept
then in much wider engineering use. To decelerate, stop, or turn the
heroic human operator used his own muscle power, multiplied
precariously through a series of levers.

Despite the name "automobile" these vehicles had no autocontrol
circuits; control, such as it was, was exercised second by second for
hours on end by a human being peering out through a small pane of
dirty silica glass, and judging unassisted and often disastrously his
own motion and those of other objects. In almost all cases the
operator had no notion of the kinetic energy stored in his missile and
could not have written the basic equation. Newton's Laws of Motion
were to him mysteries as profound as the meaning of the universe.

Nevertheless millions of these mechanical jokes swarmed over our home
planet, dodging each other by inches or failing to dodge. None of them
ever worked right; by their nature they could not work right; and they
were constantly getting out of order. Their operators were usually
mightily pleased when they worked at all. When they did not, which was
every few hundred miles they hired a member of a social class of
arcane specialists to make inadequate and always expensive temporary

Despite their mad shortcoming, these "automobiles" were the most
characteristic form of wealth and the most cherished possessions of
their time. Three whole generations were slaves to them."

Sadly all true. We've even surpassed three generations.

Now don't get me wrong. I'm totally a gear-head. I've got a bunch of tools and even spent a good chunk of today adjusting some bits of metal that thump back and forth. I love the engineering that went into creating such a device. To me they are truly are fantastic machines. However...

They lack elegance.

A truly elegant solution to a given problem is usually the simplest. It's pretty clear that today's cars are not simple. You can't even work on them yourself anymore without computer interfaces and huge toolboxes filled with all sorts of precision machines (trust me, I've bought most of them!) What we need are simple vehicles. There's just one thing holding us back: electrical storage. Electric cars really are the best. They are simple, efficient and quiet. We have had a perfect motor since 1882 so that's taken care of. In the last few decades advances in transistor fabrication have brought us both cheap micro-controllers and inexpensive heavy duty power transistors. What we lack is good power storage. Batteries have only marginally improved in the last few decades. Lithium ion batteries (0.54 MJ/Kg) are the latest and greatest and yet still have a far lower energy density than gasoline (~55 MJ/Kg). The current crop of ultra-capacitors is even worse at about 0.02 MJ/Kg. EEstor has patented a capacitor that beats LiOn at 1.0 MJ/Kg. That should be dense enough to get us going with electric cars... if it works.

Once we sort out the storage we'll be on our way. Cars will recover 90%+ of the energy used in braking. They will be efficient. They'll even be fun to drive. I can't wait til the guys on Top Gear get a real electric car to play with. I don't think that the Tesla Roadster is quite there yet, but once we get the power storage problem solved those three yahoos will be humming a different tune, though I'm sure they'll complain that the cars don't make the noises that they love.

I just wish I could build that car. Maybe one day I will at least get to work on one.
Tags: cars, electronics

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