In February, I had the privilege of attending the 12 Hours of Sebring, an American Le Mans Series (ALMS) race. The ALMS series isn't as familiar to people in the US as NASCAR, the series that originally got me interested in cars. Drivers in both series have accents; however, in NASCAR, you're distinguishing the Virginians from the North Carolinians, while in ALMS, you have to be careful about confusing the Spanish, Mexicans and the Brazilians or the Australians and the Brits. (And then there are the 'citizens of the world', but that's a story I will tell later).
In comparing the two types of racing (stock cars vs. sports cars), NASCAR is like hockey and ALMS is more like baseball. At a NASCAR race, you constantly scan the track to see where the action is. Except at superspeedways and road courses, you really can't hold a conversation because of the noise. You have to wait for cautions to communicate with your seat mates (or text them).
ALMS tracks are longer: three to five miles compared to the typical half-mile to two-and-a-half mile NASCAR track. When you go to an ALMS race, you position yourself near your favorite turn. The cars run past, then you have a minute or so to talk before they come back around again. Drinking while watching racing is common (if not mandatory); however, NASCAR's official alcoholic beverage is Coors Lite, while ALMS's is Patron Tequila. I'm a sucker for good tequila and a British accent, so I had a lotof fun at Sebring. Besides, where else are you going to see an Aston Martin sponsored by Lowes?
ALMS is a good platform for automotive industry companies pursuing greener products. The Michelin Green X Challenge, which rewards the fastest and most energy efficient cars, considers only gasoline usage at the moment, but as the series evolves, they will likely expand to include another major contributor to petroleum use in cars: oil. One of the series' sponsors, G-Oil, is a motor oil with animal origins. One of the principles of "green racing" is to minimize petroleum usage to lessen our dependence on foreign energy sources, so using a domestically available source for motor oil certainly addresses that point.
Oil plays many roles in the engine, including protecting metal parts from wear due to friction and carrying heat away from the engine. A typical passenger car uses about 5 quarts of oil. Changing the oil every 5,000 miles means you go through about 100 quarts of oil in 10 years. That doesn't sound like much, but multiply that by the number of cars in the country and the number of people who don't recycle used oil. The Environmental Protection Agency (EPA) says that two hundred million gallons of used oil are improperly disposed of each year. So not only are we increasing our dependence on petroleum, the used oil can contaminate groundwater and kill vegetation.
Gasoline and petroleum-based oil come from the same source: crude oil. Crude oil contains a veritable zoo of hydrocarbons - chains (or rings) of carbon atoms with hydrogen atoms attached to any free carbon bonds. The number of carbon atoms in each molecule ranges from 1 to 80 or more. The chart below gives you an idea of how many carbons are in the molecules that make up various petroleum products. Red lines represent gases, blue lines represent liquids and green lines represent solids. The darker blue tells you where the majority of the molecules in the substance come from.
The same length carbon chain molecules can be used for different things, depending on how the atoms are attached within the molecule. Isomers are molecules with the same atoms, but different arrangements of those atoms. For example, there are 355 isomers of C12H26 (a molecule containing 12 carbon atoms and 26 hydrogen atoms). So even though a narrow range of carbon number is present in gasoline, There may be as more than 500 different molecules involved.
A barrel of oil is 42 gallons, with a typical barrel providing about 19.5 gallons of gasoline, 9 gallons of fuel oil, and 4 gallons of jet fuel. The remainder is used in a wide variety of products, including grease, kerosene, bitumen (the binder in asphalt), crayons and plastics. Motor oils are about 90% base oil (the 'motor oil') you see in the chart above, and the other 10% are additives to decrease friction, increase viscosity, prevent corrosion and oxidation, etc.
Saturated and unsaturated fats are just as important for cars as they are for our bodies. (The general agreement as far as nomenclature is that fats are solid and oils are liquids.) Each carbon atom can make four bonds. Hydrogen can make just one. Saturated fats - like animal fats - have single bonds between carbon atoms, and single bonds between each carbon and hydrogen atom, as shown in the top part of the figure below.
Unsaturated fats (or oils ) have a double bond between the carbon atoms and each double bond decreases by one the number of hydrogen atoms in the molecule. Unsaturated fats have fewer hydrogen atoms than saturated fats. If there's one double bond, the fat is unsaturated, and if there is more than one double bond, the fat is poly-unsaturated.(Thanks to Juan for pointing out that the original in this figure violated the most fundamental laws of chemistry!)
Double bonds are more exposed than single bonds, making them more likely to react. A particular challenge is oxidation, which cleaves the carbon chain at double bonds. The extra reactivity of unsaturated fats means that the human body can break them down faster and easier. Unsaturated and polyunsaturated fats are used more quickly in the body’s metabolism, while saturated fats hang around and clog up your arteries.
In your car's engine, hanging around is what you want. Motor oils use saturated fats because they are more stable. You've probably never had motor oil go rancid on you, have you? Saturated fats stay in their fatty form far better than unsaturated fats. Saturated oils are good for your car, even if they are not so good for you. One of the problems with double bonds, though, is that they are much more likely to oxidize, which cleaves the double bond and produces two shorter molecules, neither of which has as much protective ability as the original long-chain molecule. The propensity for oxidation increases with temperature, and engines get very hot.
The desirable properties of the oil come from the particular molecules that are present. Motor oils are usually somewhere around 16-20 carbons per molecule. It doesn't really matter where the oil comes from: it can be separated out of crude oil or, in the case of G-Oil, it can come from animal fat.
G-Oil is made from beef tallow - tallow was historically used for candles, as it was cheaper than wax. Oil obtained from refining crude oil is obtained by separating out different components from the crude oil. Animal or plant fats offer some advantages in terms of processing because they contain high levels of triglycerides.
Triglyceride is a very large molecule composed of one glycerol molecule and three fatty acids. The fatty acids are represented R1, R2 and R3 in the picture to the left. The triglycerides go through a process called transesterification, which frees the fatty acids from the glycerol. Remember learning about how the pilgrims made soap from animal fats and ash? This is exactly what they were doing. The glycerol is used in soap and the fatty acids that were left were used to make candles or other products. This is also the first step you would use to make biodiesel from fat.
It turns out that the fatty acids in beef tallow have very high proportions of carbon chains in the C16-C18 range, which is the target range for motor oil. Green Earth Technologies, the company making G-Oil, has a patent pending process that converts the fatty acids into the types of chains needed for motor oil applications.
You might wonder why they don't use plant fats, and that's just because the animal fats are closer to the right composition of molecules. Plant oils have a much larger fraction of unsaturated hydrocarbons. The G-Oil website points out that grape seed oil is rich (70-80%) in Omega-6, an 18-carbon chain with two double bonds. These molecules degrade much faster than those in the animal fats. The end message is that the plant fats are better for use by people and the animal fats are better for use by cars. Green Earth Technologies points out that the amount of beef tallow they use is a small percentage of what is already being produced as a by-product of meat processing.
The oil -- and all of it's additives that protect it from oxidation, ash production, etc. -- are biodegradable, meaning that it breaks down within about a month when in contact with common environmental bacteria. Which means that, no, the oil will not biodegrade in your engine. I guess if you are a committed vegetarian, you might choose not to use this produce because it is animal-based, but other than that, this is pretty nifty idea.
Perhaps most importantly, you don't have to sacrifice performance for being green. The oil was tested against a couple leading synthetic and crude-oil-based motor oils and G-Oil compares very favorably. The ALMS series believes that motorsports is a good platform in which to test things that eventually could appear in passenger cars, as is noted on the hauler set up of Drayson Racing (shown below). Lord Drayson, the co-owner of the team with his wife, is the UK's Minister of Science and Innovation, a very cool guy who actually tries to explain what is going on in Science and Engineering to the public via twitter. I wonder what U.S. Secretary of Energy Paul Steven Chu drives...?
I haven't explained the role of nanotechnology in lubrication: that will be coming in my next post because it turns out the solution is bigger than I originally thought!