OK, so that’s Ubuntu. And here’s why the open source car people are full of bologna.
What they are calling open source means they provide CAD/CAM drawing of the car, and these drawings and plans are open source. That’s dumb. Open source cannot be applied to the tangible. Open source is a response to closed source. Closed source = intangible. You can’t open source the tangible. If you can put a tape measure on something a measure it, by it’s mere tangible existence its already “open source”
You can open source software because it’s code is intangible. You can open source the die of a microchip because blueprinting the die is so bloody difficult it rates as intangible.
You catagorically cannot “open source” something you can blueprint quickly and easily.
Further, remember that Linux was developed by brilliant professionals doing what normal folk cannot. Normal people CAN make car bodies. Fiberglass + Bondo + elbow grease = car body.
The hard part of car design, the things you really need professional help for is emissions and crash standards. To control emissions you need software running on an Power Control Module (PCM.) There is one open source PCM available and it cannot be used on emission control vehicles because it has not been EPA approved.
Crash standards can be suggested by computational anysis but require regirous testing. Once a basic chassis granted DOT approval the blueprints of that chassis could be open sourced.
But without EPA stamp on the PCM and engine, plus DOT approval of the chassis, the car is dead in the water.
The active community of users with wikis and forums and blogs is development of an effective product, not the cause of it. The open source car, as it stands is a joke.
Finally, since cars do not reproduce flawlessly like software, a certify agency will have to put a stamp of approval on cars to show that they are open source compatable, and therefore, EPA and DOT approved, as well as sharing parts interchangability with other certified cars.
I wish I could buy an Ubuntu car.
Now, there are people out there working on what they call an open source car, but I’m not super impressed with any of them yet. Further, it think their basic premise is flawed, or frankly, stupid.
Open source is a response to closed source. Had closed source not started it all, open source would not have had a reason to exist. Let’s look at the cause of open source, Microsoft.
Microsoft wrote DOS. DOS lets people talk to the computer, but DOS is still pretty obtuse. Microsoft makes a bunch of pretty pictures than normal people can use, and those pictures can talk to the DOS to talk to the computer. That’s windows. Windows was really popular, and computer code is easy to reproduce. Microsoft, like all good companies was interesting in making profit for its owners so it took steps to make it hard to sell and reproduce the code that many thousands of Microsoft programmers had worked very hard on and need to be paid for.
Linux was created as a substitute for DOS, not for windows. Essentially a guy named Linus re-wrote a old operating system for mainframes (Unix) into a new operating system for PCs. He did it because he thought computers were a force of capital G Good in the world, and he didn’t want Microsoft’s bottom line to get in the way of people being able to use computers.
Later, just as Microsoft developed a graphic user interface for DOS, a graphic interface would be developed for Linux. If fact many would be developed, the most popular is called Ubuntu.
Ubuntu is the most popular because it is, for all practical purposes, NOT Linux. Though Linus’s original code is buried in Ubuntu, it has been improved by thousands of highly skilled programmers working tens of thousands of hours. Further, Ubuntu contains a whole bundle of pre-packed goodies that make it a functional windows replacement. Those goodies were all developed by yet more thousands of programmers working tens of thousands of hours.
Despite the fact that Ubuntu was developed for free, it was not developed by amuteures. It was developed by some of the best programmers in the world over a period of years, and in some parts of the source code, decades. (The original Unix kernal was written in 1969.)
What the programmers did was what you cannot do. They did the very hardest parts, the most esoteric parts that take the greatest level of technical proficiency.
Finally, Ubuntu has a tremendous support network. Wikis and forums which explain each step in plain detail. If you can’t handle that, often in the forums, there are links to blogs which will explain tiny steps in stupefying detail.
So people seem to believe that the chronology of mass produced suspension designs relates directly to suspension quality. The usual theory goes, beam axle, swing axle, McPherson, wishbone. First let’s look at the proviso “mass produced”. Define mass produced. Is it 100 units? 100,000 units? Beam axles were the first mass produced in the sense that they were produced en mass since around 1000 BC. But you can’t just say they were the first mass produced in cars just because the Model T had them. The Model T began production in 1908. By that time, Decauville’s indpendent front suspension patents had already expired, and they had been making a car with independent front suspension for a decade, beginning in 1898.
Further, equal length wishbones are usually seen as a post McPherson strut development. Actually, they were proposed in a 1934 technical paper by Maurice Olley. The McPherson strut was not invented until ’49, but mid 1920’s technical papers by FIAT would show that they invented the concept then. So here to set you straight is the Israel Walker “real story” of suspension history.
Remember, there are four parts to suspension: axle, linkage, springs, and shocks, and you need all four. A brilliant axle with poor linkages, crappy springs, and lousy shocks will be crappy suspension. Let’s look at Model T as a baseline.
First off, there is nothing wrong with a Model T’s suspension. The roads the T was made to run on were crap. So the T had to have tall wheels. The tires available were skiny so it had to have narrow wheels. If you have tall skinny wheels clawing over rough terrain you need a huge amount of articulation. The motors available are heavy and weak, so the car (and suspension) has to be light. A modern engineer, given those requirements would give you the exact same suspension Henry did.
Beam axles get a bad rap. This site has a pretty standard Pros/Cons list for beam axles. They’re simple, and strong, with good camber control, but have high unsprung weight, gyro stability issues (the fact they have two rotating masses on a stick causes weird vibrations) bump steer (up and down make the wheels turn left and right), take up to much space, and poor road holding.
This is where critical thinking comes in. Simple compared to what? Strong in reference to what? High unsprung weight compared to what? Gyro stabilizing issues compared to what? Large compared to what? And some research about bump steer and road holding.
The problem here is that they there is more difference between Model T’s beam axle suspension and a modern high end beam suspension than there is between a kitten and tiger. Strong in reference to what? Weight. They carry more load with less component weight than any other system. This is why semis have them. And if they are the strongest referenced to weight, that means that they are one of the lightest systems, not the heaviest. Yes, they do have gyrostability issues if they have weak or poorly designed linkages. ALL suspensions have stability problems if they have weak or poorly designed linkages. The bump steer is fixable. Road holding is fantastic, if properly designs. As is the case with all suspension designs, road holding is poor if the overall execution is poor. Finally, the “too big” one is a plain lie. Most minivans use beam axle suspension in the rear precisely because of how little space it takes up, allowing more cargo space in the back of the vehicle.
I think what they meant, was it takes up the wrong kind of space. Beam axles must run in a line from wheel to wheel, meaning that you can’t put, say ,an engine, in the space between them. The original reason that GM went to independent front suspension in the 30’s was to mount the engine between the wheels instead of behind them. It was a stylistic and not an engineering decision. This was reflected in the fact that early GM IFS ate the heck out of tires.
We must compare apples to apples. It’s not fair to say that the beam axle suspension of a 1908 model T designed to conquer roads that would have appalled the Romans and do so for as cheaply as humanly possible, compares unfavorably 21st century dual wishbone designed for glass smooth roads and with cost no object. We never learn anything from comparisons of maximized systems to un-maximized systems. If we want to set high performance as the baseline, than lets look to racing.
The first Indianapolis 500 was raced in 1909. The last time a car with beam axle front suspension would win? 1962, at 150 mph. Sprint cars, racing 1200lb vehicles with 800HP engines on dirt tracks still use them, again at around 150 mph. Further, they are the preferred axle of choice for many extreme motor sports, like rock climbing. The Humvee has has been troubled by it’s lack of beam axle suspension. It’s wide articulation, fully independent suspension is far more weight sensitive than beam suspension. As such, the Humvee becomes dangerous to drive when overloaded by say, improvised amour.
Beam axle is far more simple. As such, it costs less to maximize, and more importantly, has less fail points. In the crushing loads incountered in racing, rock climbing, and warfare, the beam axle wins. Tune in next time, for a bit less detail about the swing axle, the wishbone, the McPherson strut and double wishbone, and more.
So, I don’t write many car posts. I am a freak about cars, so I know a lot about cars. I don’t just know about the cars themselves, but the companies, the people that designed them, the engineering, etc. I take cars very seriously, and having the position of knowledge that I’ve worked for over the years, I say things that people without my background don’t understand, and they think that I and not they, am the moron. (There’s two approaches to this. One, I can explain everything from start to finish. By the time I’ve given them the background to actually know what I am talking about, my point is lost. Alternately, I can make my point, have them tell me how stupid I am, and then spend an extra hour on the lecture defending every single point, since they already know the final point and don’t want to agree with it.) I am going to spin this into a critical thinking post in the next installment, so I am doing it anyway.
OK, some basic physics. Cars are heavy. In physics terms, this means cars have a large mass. Mass resists being moved, and once moved, resists being stopped. Roads are not flat. They go up and down, so anything going accross them goes up and down. When a car goes up, the wheels aren’t sticking to the road. When it goes down it the wheels are diving into the road really hard. Also this isn’t good for the car. A car is made of many pieces, if they are all made flexible, they bend and rub each other till they break. Make the car rigid, and the constant force without flex to absorb it will also break it. So we we make suspension.
Springs in the form of wood have been used on chariots since Egypt. By the 19th century, they were steel. Cars inherited these steel springs. The problem was that cars went faster than horses, so something had to link the axle to the car besides the springs, to keep the springs from just bending out of the way. This is called linkage. As cars got faster still, on new problem was found. The car would bounce on the springs so fast that it would vibrate the car to pieces, so the shock absorber was invented. The shock absorber lets the spring bounce but slows it down, like the difference between swinging your arm in water instead of air.
So, their are 4 parts to suspension. Axle (what the wheel spins with or around), springs (which connect the axle to the car), linkages (which keep the spring from flexing right out of from between the car and axle) and shocks (which keep the spring from bouncing excessively.) Whether we are talking about a Model T, or a Formula 1 racer, that’s it: 4 basic parts consisting of axle, springs, linkages, and shocks.
The truly astute will notice that we have not solved the first problem, just make it smaller. Remember that moving the car horizontally causes vertical motion. Mass resists moving, and once moving resists stopping. Now, it is the much lower mass of the suspension doing the vertical movement while the car pretty much floats over. This car is mounted on springs, thus is “sprung mass”. The wheel and axle are not, thus “unsprung mass” (Some parts are both, the part of the spring which is fixed against the car is sprung and the part attached to the bouncing axle is unsprung. So we figure 1/2 the mass of the spring is unsprung mass.)
But cars don’t just go straight. They turn. Remember that an object in motion wants to stay in motion and that the car is heavier than the suspension? When you make a hard right, the lighter suspension pretty happily changes direction. The rest of the car wants to follow the old path of motion, now to the left. It tries do slide to the left, and pushes against the suspension, so it “rolls” left, squishing the left springs and stretching out right springs. If the body rolls enough it will pick up the right-side wheels off the road. Sometimes this is no big deal. Sometimes you die in horrible agony. Depends on the road, and the car. Anyway…
So, to recap so far: The suspension has one job, to keep the tires on the road. It must keep the tires on the road when the road tells the wheel to pull away, or when the cars body roll pulls the wheel away. It does this with 4 parts: axles, springs, linkages, and shocks.
Totally unrelated to the problem of keeping the rubber in the road is the task of passenger comfort. And totally unrelated to that is the production engineering. Bearing that in mind, here is the normal time line of front suspension development. (For reasons I’m not going to explain, new technology goes into the front end first, then is translated into the rear suspension.)
Ok, so first is the beam axle. Its a big pole with wheel on each side. Then comes the swing axle which is the same thing with a pivot in the middle. Then comes the McPherson Strut, then the equal length wish bone, then unequal length wishbone.
The problem is? That’s crap. Despite the fact that absolutely everyone says that the time line, it’s not. And it doesn’t go from bad handling to good handling in good order, which is it’s usually presented: a timeline with improving ability with each development.
So, a kind of battery is being developed called the nanowire lithium battery. I’m not much on electrochemistry, so I can’t tell you why having more lithium in the right place makes it work better, but I can tell you how. The chemical relationship of silicone to lithium is such that a little bit of silicone chemically holds onto a lot of lithium. They tried making silicone wires, but they cracked when electricity was passed through them, no small problem for a rechargeable battery. Dr. Cui made nanowires of silicone bonded to stainless steel wire. This gets around the cracking problem and allows 10 times more power density than is currently available from lithium-ion (li-on) cells.
He hopes it will be mass market ready by around 2013. One likely application is electric vehicles. I’m excited about it. Electric cars have enourmous benefits compared to normal cars running normal engines. Namely, mechanical simplicity. A battery electric vehicle needs a motor, a battery pack, and a controller. The controller is complicated at a microlevel, as it’s a large quantity of integrated circuits, but to the auto manufacturer or mechanic, it’s a just a brick. Moving electrons beat precision moving parts every time. Also, electric vehicles take the emissions problem from 100,000 engines built to wear out in 5 years dumping into 100,000 tail pipes and put it all into one power plant with every part designed to give the best performance dumping into one easy-to-monitor smoke stack.
The problem with electric cars is one of energy storage. The lithium ion nanowire battery (hereby called the Lionwire) has an energy density of 2.6 MJ per kilogram. (Don’t know what a MJ is? Megajoule, or 1 million joules. Joules are a universal measure of energy that can be used to measure, heat, electricity, etc. Handy thing to compare different energy densities because it’s universal between all types of energy. A joule is very small, so MJ are the most convenient here.) Anyway, the lionwire battery has 2.6 MJ/KG. Gasoline has 46.4 MJ/KG.
That’s not quite as bad as it looks. A good electric car will be able to get 80% of the power that goes in down to the road. A good gasoline engined car, 17%. 80% of 2.6 is 2.24. 17% of 46.4 is 7.89. So, gasoline still holds 350% more energy per pound than the lionwire cell.
Well, with all the support systems for the gasoline engine out, don’t we get some extra weight allowance? Yes. The engine and transmission are gone, replaced by a advanced AC or DC motor. No cooling system is needed, and no fuel system. To actaully run this, we will need some real numbers.
Using the example of a Ford Focus, we can remove the engine (400 lbs with alternator and oil) the transmission (135 lbs with fluid) the radiator and coolant (15 lbs) and fuel system (100 lbs) We took 650lbs out. We do need to put in a motor and controller. I’ll use the Advanced DC FB1-4001A with a Curtis 1231C-8601, which has a 100HP peak rating same as the Focus OEM engine. Unlike the OEM part, however, it weighs just 200 lbs including the electronic controller. So we have 450lbs left over, or 204 kilograms.
The Focus has a 13.2 gallon tank, thats right around 80 lbs of gas, or 36 kg. 36kg times the post powertrain energy density of 7.89 is 284 MJ. The original energy storage of the car is 284MJ. However, 204 kg surplus gained by removing the engine and its support systems times 2.24 is 457 MJ. That’s gain of 160%!
That’s right, ladies and gentleman. We finally have a battery that will yield equal or greater systemwide power densities than gas!!! It’s not perfect, recharging still much slower than filling a tank of gas, and they will probably cost much more for awhile, but the days of the internal combustion engine car are numbered!
In 1816, the Reverend Robert Stirling invented a engine. From time to time an astute reader will hear about this engine as the solution to the world’s problems in general, and as the perfect candidate for automotive hybrids specifically. Pure bunk and here’s why.
First, you have to know a little about hot gas. (Gas like air or CO2, not like gasoline.) When gas is heated, it wants to get bigger (ie. increase in volume). When it has its heat removed (cooled), it wants to decrease in volume. If it is in a sealed container, it can’t increase its volume, so it presses against the walls of the container all the harder when heated (pressure). That’s why aerosol cans say to not expose to temperatures of more than 120 degrees. They are full of gas at a certain pressure and if they get too hot, the pressure gets too high and they pop. (Also, if you have a weak container, like an empty closed pop bottle and stick it in the freezer, it will collapse. The removal of the gas’s heat causes a reduction in volume, which reduces the pressure, meaning the air pressure on the outside is higher, and it squishes in.) There are mathematical formulas that describe these relationships of pressure, volume and temperature called gas laws.
A man named Carnot (above) put all of the gas laws together and drew some rational conclusions. He performed a thought experiment about the perfect heat engine. (An engine being a device for turning heat energy into mechanical energy.) The perfect heat engine would be made out of a magic material which would let heat in but not out at one point, and out but not in at another. It would have no friction, and would never leak. That way, any energy flow could be controlled and monitored.
(1.) Heat would be added perfectly instep with the expansion of the gas, so that no energy was wasted. (Heat is added but the temperature doesn’t increase, because it’s expanding instep.) It expands while taking heat, pushing the piston down.
(2.)The heat in the gas is then “used up” as the gas continues to expand without new heat. It expands while cooling, still pushing the piston down.
(3.)The heat is then removed from the gas, causing the gas to shrink (reduce in volume), pulling the piston in.
(4.) Now the piston is pushed in (further reduced in volume), raising the temperature of the gas back to the temperature it was before the heat was added in step 1.
For various reasons deduced from the gas laws, Carnot’s engine is the most efficient on earth. Since we know what perfect is, we know the best way to design any engine on earth.
Though every part of Carnot’s cycle is right, none of them are true, and therein lies the problem. There is no material which can conduct heat only in one direction, give us choice of direction, and switch direction at whim. There is no gas which behaves exactly as the gas laws say they should, though hydrogen approaches it. There is no material that is totally frictionless and perfectly sealing at the same time. Carnot’s engines says the key to efficiency is the difference between the temperature of the heat input in step (1) and the heat removed in step (2).
Material science is the kicker. The engine’s material must be a good conductor of heat or the heat in it will build up until it melts. But it must not be too good a conductor of heat or it will take heat out of the engine which the engine is supposed to be making power out of. It must allow a tight seal for the piston but without to much friction.
Long story short, the engine must be all at once: a good conductor, insulator, bearing surface, and pressure vessel. Due to the properties of combustion, it must do all of this while white hot and resistant to corrosion.
In the case of the Otto engine (the kind most likely in your car), you can add to all of those challenges this: the heat is not made outside the engine, but in it, and the gas not heated by an outside source, but within the cylinder itself by flame. Furthermore, there are the complexities of piping the gas in and out.
At this point one might cry, “Wait a moment! Do you mean to tell me that the efficiency of an engine is based of the difference between the temperatures at the beginning and end of the cycle? My exhaust manifold GLOWS red! I must be throwing away a huge amount of energy!” Yup.
And that’s a very good thing. The reason you can afford a car is because the Otto cycle, with all its oddities of valves and spark plugs and not reusing the working gas, dumps excess heat out the exhaust stream. If it didn’t, the engine block would need to be made of the same alloys that jet engines are made of, instead of cast aluminum or cast iron.
So, here’s the danger of a little information. (And full circle back to the Stirling engine.) The Stirling engine does not burn inside the engine, it burns outside of it. Its gas is sealed away inside. Of all the engines in the world, Sterling comes the closest to Carnot’s imaginary engine in its cycle. Only in its cycle. Remember that Carnot’s engine is imaginary and made of unobtanium? Carnot’s cycle only has meaning as a thought experiment because you can’t make an engine out of magic alloys which do not exist.
People read that the Stirling engine is theoretically the most efficient heat engine and assume they don’t have one under their hood because it was simply never maximized. Actually it is not that it has not been maximized but that it CANNOT be maximized. Though combustion creates temperatures of thousands of degrees, the Otto engine need not operate at that temperature. If a Stirling was going to operate at that temperature the heat would have to move through the engine and then into the gas. So the engine block, under full power generating stress, must be hotter than the low stress exhaust pipes of an Otto cycle.
Though invented in 1816 to save people from the danger of boiler explosions, the Stirling was never widely used. Steam engines are also external combustion engines, but they have the boiling of water to serve as a temperature regulator. Stirlings do not have this, and a frequent and persistent complaint is burnt out parts.
Another HUGE misunderstanding about Stirling engines is their ability to use very low temperature differentials; that is to say, freakishly small differences between input temperature and output temperature. It’s true. In a 72 degree room, a small Stirling can run off the heat of your palm. These tiny engines create just enough power to overcome their own friction. What would happen if you scaled it up? You would have an enormous engine with equally enormous bearings. Again, the engine would create just enough power to overcome its own friction.
But just for the sake of argument, let’s say you had a truly enormous engine, one the size of a house. The hot part is in the sunshine, and the cool part is in the shade. The low temperature difference would be overcome by the truly enormous amount of energy available, right?
A qualified no. The smaller the temperature difference, the greater amount of gas the engine has to pump around to get the same amount of power. There’s no free lunch. For the same amount of power, high temp = small working mass, low temp = large working gas. The losses to pumping all that gas through the small passages necessary for heat reclaiming mount up very quickly. For this reason, efficiencies are very low. While low efficiencies with free power (like solar) are OK, it’s a niche application.
Another route to efficiency is high pressure. Reverend Robert made his Stirlings low pressure and large (For instance, about a cubic foot of displacement per horsepower, or 172,800% larger than an Otto cycle of the same HP.). The modern trend is to make them high pressure and small. But then they must be filled with inert gas and sealed just so, because if air and lube oil are pressurized and heated the Stirling engine becomes a bomb. This is also why Rev. Stirling could make his engines with a foundryman and bricklayer and modern engines are “lab queens” in college physics departments.
Finally, another story that pops up now and then is Ford’s Stirling research in the 1970’s. Yes, they made a Stirling engine. No, they didn’t produce it. They didn’t produce it for the exact same reason Chrysler didn’t produce its turbines nor GM its Wankle. Material science could not mass produce certain key components at low enough cost to get enough people buying. This, in turn, means mass production could not be used, further raising the price and decreasing the market in a vicious catch-22.
Don’t get me wrong. I think Stirlings are cool. I think they have applications to green science. But we will never see one in a car produced by market forces. Further, if you want to invest in expensive technologies, fuel cells have higher real world efficiencies than Stirling’s theoretical ones.