The Story of Peak Whiskey

The comment I got on yesterday's post about the 150th birthday of oil makes me think I have to talk about it one more time. The comment says the idea that the Earth will stop producing oil is nonsense. And the comment is right. The Earth will not stop producing oil. Except that is not the problem either.

Let me tell the story of peak whiskey. A hundred or so million years ago some guys set up a still that can make 1 barrel of whiskey per day. Then they build a giant glass to hold all this whiskey with a spigot down on the side to get it out. But something happens and it never gets used. Just stays locked up somewhere with the still on. Each day for a hundred million years that still pumps another barrel into the glass.

Until now. Now is when a down on his luck barkeep finds that giant glass of whiskey, holding billions of barrels of whiskey and that old still churning out another barrel every day. So he sets it up in the attic of his bar. When he opens the spigot just a little bit, a geyser of whiskey comes shooting out. Remember that the fuller a tank, the higher the pressure at the bottom and the more liquid will come out per second from a spigot.

So that old barkeep starts selling whiskey on the cheap. It is good whiskey but he has more supply than he can sell, so he sets the price low. People come and buy that whiskey up. Every year there are more and more people wanting that cheap whiskey. Now two things happen. As the demand goes up, the amount coming out the spigot per day is not enough. So the barkeep just cracks the spigot a bit wider and he meets the demand again. But over the decades as the whiskey glass starts to drain, the pressure at the bottom drops and the rate out the spigot drops too. But again the barkeep just cracks it a bit wider to compensate.

Decades go by. The pressure slowly drops more and more as the level in the glass goes down. The demand keeps going up and up. The spigot opens wider and wider. Until one day, the old barkeep goes to open it up a little more, and he can't. The spigot is already open all the way, far as it can go. The still up top is still pumping in a barrel a day. But the demand is now 80 million barrels a day, so the production rate is just too small to even notice. There is still lots of whiskey in the glass. It is about half full, so there are still billions of barrels of whiskey in there. It is just that he can't get it out faster than 85 million barrels a day.

His customers start wanting 90 million barrels a day. And every day the pressure is slowly going down. He has a bigger and bigger demand, and his supply per day is dropping. So what does he do? You got it. He raises the price. Because now he is not in a market where the supply is way more than the demand. Now there is more demand in the market than supply. Over the next decades, there is still whiskey to be had, millions and millions of barrels a year, but not enough to satisfy everybody. So the price just goes up and up and up.

Now the situation with oil is about the same. The Earth is still making oil as fast as ever, but that is only barrels a day. May as well be zero. We have billions and billions of barrels of oil still in the ground. But the rate we can get it out is flattening and will probably begin going slowly down. We will extract 80 million barrels a day for a good while still.

Now the idea is this: beginning about now, the supply of barrels per day is not going up any more. It will probably start going down. At the same time, China, India, Brazil and the rest of the world want to use more of it. A lot more. The result is going to be like with the whiskey: higher prices for oil and therefore gas. Even though the Earth will not stop making it and we still have billions of barrels of it. The shortage we are going to have is extraction rate.

These phases are common. Once you get a little older, you see that things come and go. A good example is with computer speed. Fifty years ago there were no computers. Then they invent them, and for about 30 years they got faster and faster. Remember in the 80's fast machines were a couple of Megahertz? That constant increase lasted a long time, but now it has stopped. Have you noticed how for about the last 5 years the speed hasn't gone much above 3 GigaHertz? That's because the engineers hit a wall ... making chips much faster than 3 GHz is not technically feasible right now.

But notice what happened. The computer industry changed course. When they couldn't make their chips faster, they made them smaller and put more than one together. Now you can buy quad core chips. Four chips, all at the same 3 GHz speed of five or six years ago. The lesson here for the auto industry is that times can change and they do change. The times of cheap oil and gas are on their way out. But that doesn't have to mean the end of the auto industry.

They have to adapt to the new course, like the computer industry did when chip speed stopped increasing. Any software company in the year 2000 that was developing a program that would only run on a 10 GHz single core chip would be out of business, because they were wedded to a course that stopped running. I think that is what is happening to Detroit. Detroit has always played by the rules that oil is cheap, and those rules are changing. If Detroit can't adapt to the new rules, they will vanish like the software company that needed 10 GHz single cores.

Happy 150th, Oil! So Long, and Thanks for Modern Civilization

August. 27, 1859 the first oil well in the world was sunk in Pennsylvania. Over the following 150 years, the energy provided by oil has allowed the development of cars, highways, plastics and and modern agricultural revolution. Now we are facing the end of that era. It looks like global oil production is now at an all time high - a phenomenon known as peak oil. From now on, the total oil produced every day will go down. Whether the decline is fast or slow remains to be seen, but down it will go. This means we will be forced to find a different path for the future. Either we must find new energy sources or learn to use less. In a time of concern over rising carbon dioxide levels we must make sure that any future change in energy sources is not a big CO2 producer.

I think the recently passed 150th birthday of oil is something we should all be aware of. The role that oil and modern fuels play in our lives is enormously important and despite that it is all to easy to not be aware of their impact. Better to at least know by name what you depend on!

NItrogen in Your Tires

The picture shows liquid nitrogen being poured ... that super cold stuff you see in science demos. Air is about 80% nitrogen. Why would you want it in your tires, and how would you get it in there?

Both nitrogen and oxygen as found in the atmosphere form biatomic molecules. However nitrogen molecules are larger than oxygen molecules. The idea is this causes nitrogen to leak more slowly meaning you can go longer between tire refills without problems. Also because natural air has water in it and pure nitrogen does not, the nitrogen filled tires are effected less by heat. Finally, the oxygen in air can over time degrade the tires.

It is possible to find tire shops that offer pure nitrogen fills if you just look. To read more about nitrogen in your tires, follow the link!

Guest Post: Adventures in Hypermiling

Hello everybody! I´m Gen.

Geoff had to deal with an unexpected power outage and subsequent disasters so he asked me to do a guest post. I hope you all bear with me, because I´m not the expert that Geoff is. In fact I´m pretty much an all-around car disaster, as you´re about to see.

This is the story of the first (and last?) time I ever hypermiled.

I was 16 years old and plain old crazy just like all 16 year-olds get when they first get their driver´s license. My dad lent me the car to go to band practice but I decided to visit my best friend instead. Of course Dad probably knew that I would be tempted to step out and run away from band after signing the attendance sheet, but as the tank was basically on empty he thought he could trust me. Little did he know to what extent I was prepared to go.

The first couple of miles I tried to go really easy on the gas pedal, but that meant that the car went Slow, way to slow for a girl on the move like me. Teenagers do not like to go slow. Slow is neither cool nor gratifying.

Then I came upon the insight that coasting through intersections would really cut down on the stopping and starting. It worked like a dream for the first few stop signs in a quiet residential neighborhood. The highlight of my ride was when I successfully stared down an elderly lady driving a minivan. She might have technically had the right of way, but I obviously ruled the road.

The next tactic I tried was shifting into neutral and coasting down some hills. That was good but it didn´t really save that much gas, and by now the gas gage was alarming. So I turned off the engine on the next hill. Now that was gratifying. Thanks to the rolling hills in my home town I was able to coast for almost a minute before turning on the car.

A mile before my friend´s house I had to turn off onto a steep gravel road. Everything was working fine, and it looked like I would be able to reach my destination before the tank ran out. I should have counted my blessings and left it at that. But teenagers never do.

Inspired by my god-like powers of fuel economy, and gifted with a mpg that would make hybrids weep, I tried coasting down the gravel road with the engine turned off. To my credit it did work until the first switchback turn, when I used up the hydraulic pressure in the brakes. Then I tried to start the car, and the engine wouldn´t turn on. Then I had to take another switchback turn and realized that the steering wheel didn´t work so well with the engine turned off.

Fortunately the crash wasn´t so bad for me, the car or the tree. With the help of my best friend, her brother and his friends we managed to get me and the car home. However, explaining to my Dad how on earth I managed to get wood chips into the front bumper and why there were pine needles in the back seat was quite a task.

To summarize I highly recommend that all of Geoff´s readers think twice before using advanced hypermiling techniques, especially on switch-backed gravel roads.

TTFN!

Aerodynamic Wheel Covers

Fancy wheel covers with swirls or spinny things can look nice, but they have a fuel economy cost. At higher speeds, the dominant friction force that your vehicle has to spend gas fighting against is air resistance. Cars with big open wheel wells or wheel covers that are not smooth and flat are generating extra turbulence and drag. If your car already has pretty smooth covers, replacing them may not make much difference, but if you have something tricked out and drive fast a lot, you could improve your fuel economy a couple of percent by switching to something smoother. This thread has a fellow claiming a 4% improvement after replacing his wheel covers with large pizza pans!

Check Your Tire Pressure

Try to always keep your tires inflated to the recommended pressure. Under inflated tires will suffer premature wear and need to be replaced sooner. They will degrade the handling (and thus safety) of your vehicle. And of course, they will lower your fuel economy. This video clip from Edmunds shows how you can easily keep an eye on your own tire pressure. The most important lesson? You can't tell by looking if your tire pressure is slightly too low. You have to check the pressure using the right gauge.

Could a Motorcycle Be an Option?

If you are looking to save on gas, why not consider a motorcycle? Due to their low weight, they have potential to use much less fuel. Two things working against motorcycle fuel economy are the fact that most have very high power to weight ratios and run their engines at RPMs much too high to be efficient. Also motorcycles have a bad aerodynamic profile. But if you get a bike with a small engine (say 50cc) and drive it slowly to avoid air resistance, you can easily get close to 1.00 gallon per hundred miles.

They are riskier to drive though. According to the National Highway Traffic Safety Administration in 2006 the fatality rate per mile was 3 times higher for motorcycles than cars. Also the cargo and passenger capacity is much less. There is also the inconvenience of uncomfortable weather, like rain or extreme cold.

If you find yourself making a lot of solo trips without cargo or passengers in good weather and calm traffic you might be able to save a lot on gas by making them driving slowly on your small bike. You could buy the bike in addition to maintaining your old vehicle. You have lots of used scooter and small bike options for under $3000. Why not think about it?

Smaller Vehicles Designed for Maximum Utility

We are at the last in our series. The purpose of a car is to move passengers and their cargo. If we can design the smallest, lightest car that does this, we will get better fuel economy. However to meet standards of comfort and provide sufficient cargo capacity it is not possible to just miniaturize everything. The idea is to rearrange the interior space of the car to make the space inside as usable as possible while keeping the overall shape as tightly fit to the interior as possible. Some of the techniques that can be used are illustrated in the Mazda Washu concept.

The Washu has features such as steer by wire, which allows reduction of the steering column. Additionally the steering wheel can stow away to provide even more space when parked. The beltline is widened outwards to give more interior space. The feel of roominess is enhanced by putting windows everywhere possible. The rearmost seats can be efficiently folded down to carry long cargo. The rear cargo door consists of a combination of a hatchback and a tailgate that slides straight down vertically (instead of swiveling on a hinge to be parallel with the ground) to make it as easy as possible to load bulky freight. The cabin roof is arched to open up a little more volume.

Design attention like this can open up more space for passengers and cargo without needing to make the overall vehicle larger. This means that there is less structure per usable functionality, and that in turn means carrying around less metal with you. The result is a savings on gas.

Lighter Construction with Composites and Lighter Metals

Here is number six in our series looking at fuel economy technologies. If a vehicle can lower its weight it will be able to run with less fuel. There are two main reasons for this. One is that the mechanical friction suffered by the vehicle is proportional to the weight. A heavier vehicle has to spend more fuel fighting more friction. Note that this does not apply to the aerodynamic air resistance friction that begins to really bite at higher speeds. The air resistance does not increase with vehicle weight, assuming the shape of the body stays the same. The other is the investment in kinetic energy to speed up the vehicle. The amount of kinetic energy needed to reach a given speed is proportional to the mass. So to speed up a heavier car, you have to burn more fuel. Then when the car slows down or stops, all of this energy is lost, mainly as heat in the brakes. Heavier car equals greater loss in this way.



The video above explains the Rocky Mountain Institute's Hypercar concept. It is a car made of only fourteen panels of carbon fiber composite. The carbon fiber has half the mass of steel. Because there are only 14 pieces the overall strength of the body is greater than if it were made of steel. The result is a much more fuel efficient vehicle.

NuVinci Continuously Variable Planetary Transmission

The transmission is the connection between the speed of the engine and the speed of the vehicle. Conventional transmissions provide a series of gears. Each gear has a fixed ratio between engine speed and vehicle speed. If you wish to go at a given speed and your transmission has for example five gears the engine has to run at one of five speeds. Each engine is most fuel efficient at exactly one specific RPM. If none of the five speeds is at that RPM, your engine will not be able to drive you at your chosen speed as efficiently as possible.

Continuously variable transmissions provide a range of ratios between engine RPM and driveshaft rotation (vehicle speed). This allows the engine to always run at its most fuel efficient RPM. Changing vehicle speed is accomplished by changing the transmission gearing ratio instead of the engine RPM.



There have been many implementations of continuous variable transmissions using a variety of techniques. Good old Wikipedia has a list of automobiles using them. Although automakers have only really been getting serious about their use in the last five years or so. Fallbrook Technologies has recently been developing a new type : the NuVinci. Watch the video above to see how it works. I think it is an ingenious mechanical system. This is a planetary continuously variable transmission. The name comes from Leonardo da Vinci, who first invented continuously variable transmissions 500 years ago. And Detroit has only seen the value about 5 years ago. Oh well, better late then never.

Turbo-Compounding

We have come to number four in our series. Turbo compounding is a method for recovering otherwise lost energy from the exhaust of a normal internal combustion engine (ICE). The design puts a turbine in the exhaust manifold which collects the kinetic energy (energy of motion) of the escaping exhaust gas. This turbine then transfers the power it generates to the crankshaft. The transfer is usually made by a hydrodynamic linkage, like in a transmission.

There are two basic types of turbines that operate by extracting energy from either the velocity (kinetic energy) of the working fluid or the pressure of the working fluid. In the case of pressure turbines there must be a large pressure drop across the rotor blades. This type is not used in turbo compound engines because the pressure drop restricts exhaust outflow, smothering the engine. Instead of pushing exhaust out against atmospheric pressure, the engine has to push it out against atmospheric pressure plus the turbine pressure drop. Using kinetic turbines avoids this problem.

Note that this is different from a turbocharger. In turbocharged engines there is a turbine powered by the flow of exhaust gases, but instead of adding this power to the driveshaft of the engine directly it is used to run a compressor which pressurizes the intake air. This results in a density boost, filling the cylinders with more air (and thus more oxygen) per charge. Since the ultimate limit on the energy you can get out of the combustion is set by the amount of oxygen present, turbochargers also increase power output. The mechanism is different though.

Turbo compounding allows for more power output given the same fuel input because it captures energy that would otherwise escape as exhaust gas velocity. However, the power per weight ratio is lower due to the turbine. The engine is also bulkier. But it is possible to greatly increase either the power available or the fuel economy or a mixture of both.



Although some World War II era aircraft before the development of turboprops used turbo compounding the technology has not been used by automakers. That is now changing. For example, the Daimler Trucks Detroit Diesel DD15 uses turbo compounding. The video above talks about the turbo compounding at about the 3:10 minute mark. Note there is also a turbocharger on this engine. Once again, turbo compounding and turbocharging are two different methods for recovering energy from the exhaust gas.

Perhaps someday soon car engines will also feature turbo compounding.

Variable Displacement Engines

Here is number three in our series of posts. The displacement of an engine refers to the total volume covered by the piston stroke inside the cylinders. Note that it does not include the heads. This is because the thermodynamic work done by the engine happens when the piston is forced down under the pressure of the hot combustion products.

Variable displacement technologies use mechanisms that can change this active piston swept volume according to the power demanded of the engine. When the engine needs less power the displacement is reduced and when the engine needs more power it is increased. It is more efficient to run a smaller engine at normal power output than to run a big engine at a bare idle. This is because the big engine has to be throttled way back and it suffers heavy frictional losses trying to suck in air. The energy lost while sucking air into the engine and pushing it back out on the intake and exhaust strokes is known as pumping loss.

The conventional way to reduce the displacement is to shut off some of the cylinders. For example, the 2008 Honda Accord V6 three, four or all six cylinders depending on the load. A management computer directs the switchover between different numbers of cylinders in use.

More advanced non-conventional techniques also exist. The Hefley engine controls the displacement by moving the average position of the pistons up and down the cylinder. To be able to do this required a complete redesign of the engine layout.

According to Wikipedia the first variable displacement engine was built over a hundred years ago (although it was a stationary engine). The first try at commercial use in cars was by Cadillac in the 1980s but failed due to mechanical breakdown being too common. Only as recently as 2004 was there mass commercial deployment of this technology. One cannot help but wonder if this fuel saving tech might have been developed and deployed a decade or two earlier if Detroit had made it a priority.

Variable Valve Timing

This is the second in our series of seven fuel economy technologies Detroit could have pursued but did not. Although almost all of the world's automakers have made at least one engine with variable valve timing within the last 10 years, before that time they were rare. Even today the majority of engines have fixed timings.

The video illustrates the idea. Basically, the fuel-air intake valves and the exhaust valves open a certain distance and stay open for a certain time. Also the location in the piston cycle at which they are open is important. At a given RPM, the engine has to open the valves different amounts at different positions for different times to get maximum efficiency. If the valves have fixed timings, the engine will only be at its top efficiency at one narrow RPM band. However, if the valves can modify their timing, the engine can reach high efficiency over a wider band of RPM.

In normal operation, there is a moment near the end of the exhaust stroke when the exhaust valve and the intake valve are both open. Also the exhaust valve stays open a little while into the intake stroke. This time when both valves are open is known as the overlap, and is one of the most important variables to control. At low RPM, the overlap should be low. This is because at low RPM the airflow is fast relative to the engine speed. At high RPM, the engine is moving so fast relative to the air that it is better to open the intake valve early so that the air has a better chance to enter.

The first vehicles with variable valve timing technology were not introduced to the US market by Detroit. Instead Alfa Romeo, Nissan and Honda blazed the trail. One more chance missed by Detroit.

Miller Cycle

Today is the first of our seven fuel economy technologies that might have been deployed by Detroit on a mass scale but were not. The standard 4 stroke engines we have in our cars today use the Otto cycle. The Miller cycle was developed by Ralph Miller in the '40s and is also a 4 stroke cycle. It has been used commercially: the Mazda Millenia S had an engine using it. This Mazda engine was a 2.3 liter V6 that generated 210 horsepower and got 3.57 GPHM (Gallons Per Hundred Miles) highway driving.

The difference between a Miller cycle and an Otto cycle is in the compression stroke. The other 3 strokes are the same. In the Miller cycle, the intake valve is left open during the first 20% or so of the piston's rise up the cylinder. That means during the first part of the compression stroke, there is actually no compression. The fuel-air charge is forced back out of the intake valve instead of compressing. Then the intake valve closes and the remainder of the compression stroke does compress the charge. So that is the difference in the Miller cycle. The Miller cycle has unequal expansion and compression factors. The expansion phase uses the whole cylinder, while the compression phase uses only 80% or so of it.

If we build a Miller cycle engine so that it has the same size compression stroke as an Otto engine, it will be bigger. This is because the 80% of the cylinder that is used for compression in the Miller engine will have the same size as the whole 100% of the Otto cylinder. Looking at the diagram, the shaded area on the right shows the extra work that can be extracted from the Miller engine. The basic idea is that by lengthening the expansion stroke we give the engine extra time to extract useful work from the explosion that drove the piston down. By maintaining the same compression ratio, we do not have to worry about higher temperatures or pressures. But there is the problem of increased cylinder length. Miller cycle engines have the intrinsic disadvantage of lower power to mass ratios.

In practice, what is done is to build a Miller engine that is the same overall size as an Otto engine which means that for the same compression ratio the volume of cylinder that holds fuel air charge will be smaller. So for the same size, a Miller engine will be more efficient, but have less power, because there is less fuel-air mix to burn on each cycle. To compensate for this, it is common to add a supercharger to the Miller engine.

A supercharger precompresses the input fuel-air mixture, meaning it is denser. Although only 80% of the cylinder volume is useful for holding the fuel-air charge (because 20% got blown out) the denser charge means that the total amount of fuel is the same. Superchargers use some of the engine output power to run themselves, but even so a supercharged Miller engine can provide the same power output as a equal sized Otto engine while remaining about 15% more efficient.

So the question now is why has Detroit not invested in the Miller cycle? I think it is because of the costs and technical complications involved with the supercharging system. If Detroit wants to build Miller engines of the same size as their Otto engines, they need superchargers to get the same power output. The supercharger is the solution to the power to weight penalty Miller engines have. Until recently, the 15% gain on fuel economy was not worth the trouble and expense of including the superchargers. We will see if that begins to change in the future.

Could we Have Had Better Fuel Economy?

The average fuel economy of the US vehicle fleet is not very good. Sure, this is because until recently oil and gasoline were cheap like water. Now that is starting to change. With countries like China and India beginning to reach high standards of living the demand on global resources is set to soar. And at the same time, some of those resources are going past their peak, like for example oil. The result is that in the future fuel economy will be something to care about.

Look at this abstract and you can see that in the whole history of the automobile in the US, the fuel economy has been poor. I didn't buy the paper, so I am going to quote only the abstract below, but it gets the idea across. Also note that I converted the MPG numbers in the quote to GPHM, so it is not a straight quote.

This article documents and analyzes the changes in fuel efficiency of vehicles on US roads between 1923 and 2006. Information about distances driven and fuel consumed was used to calculate the on-the-road fuel efficiency of the overall fleet and of different classes of vehicles. The overall fleet fuel efficiency decreased from 7.14 GPHM in 1923 to 8.40 GPHM in 1973. Starting in 1974, efficiency increased rapidly to 5.92 GPHM in 1991. Thereafter, improvements have been small, with efficiency reaching 5.81 GPHM in 2006.

So the vehicle fleet considered en masse went from 7.14 gallons per hundred miles in 1923 down to 5.81 gallons per hundred miles in 2006. That is an improvement, but it doesn't seem like much considering that we are talking about 83 years. Of course in that time we added more weight to our vehicles, drove them at higher speeds and added all kinds of powered comforts like air conditioning. In fact, most of the technical advances in cars and trucks are in these other areas because fuel economy was never a concern.

But what if fuel economy had been a concern? Could Detroit have followed a different path and left us today with better fuel economy? I think the answer is yes, and so do other people. Here is a comment giving a list of changes Detroit could supposedly make to improve fuel economy by 40%. The list is copied here:

• Miller cycle
• variable valve timing
• variable displacement
• turbo-compounding
• NuVinci-style CV transmission
• lighter construction with composites and lighter metals
• smaller vehicles, designed for maximum utility

The next 7 posts here on Save on Gas will look at each of these technologies to see what advantages it could provide and speculate on why it has not been widely deployed by Detroit.

How Can GPHM (Gallons Per Hundred Miles) Help?

Using MPG (Miles Per Gallon) to measure the fuel economy of a vehicle can lead to some wrong impressions. It is not that there is anything wrong with MPG itself, just that it measures something that we don't normally use. Much better is to think about fuel economy in GPHM (Gallons Per Hundred Miles). Here is an example that shows how easy it is to be confused with MPG.

Assume you have a car that gets 10 MPG in the city and 20 MPG on the highway. Now this car goes on a trip that is 10 miles in the city and 10 miles in the highway. Over this 20 mile trip, what is the average MPG that you got? If you said 15 MPG you are mistaken. It looks like it should be 15 because 15 is the average of 10 and 20. But unfortunately MPG does not work that way. Let us see why not.

Over the first 10 miles in the city your car used 1 gallon of gas because it went 10 miles and gets 10 miles per gallon. Over the next 10 miles on the highway, you car used 0.5 or one half gallon of gas because it went 10 miles and gets 20 miles per gallon. This means your car used 1 gallon plus one half gallon or 1.5 gallons for the whole trip. The total mileage of the trip was 20 miles. This means the MPG for the trip was 20 miles per 1.5 gallons or 13.3 MPG! Not 15 MPG.

What happens if we use Gallons Per Hundred Miles or GPHM instead? To convert MPG to GPHM divide 100 by the MPG rating. The car gets 10.0 GPHM in the city and 5.00 GPHM on the highway. If we average 10 GPHM and 5 GPHM we get 7.50 GPHM. Is that the right answer? If we convert the 13.3 MPG we found before, it comes out to be 7.50 GPHM on the nose.

So you can average out GPHM ratings and you can't average out MPG ratings. This is a perfect example of why we would be better off using Gallons Per Hundred Miles (GPHM) and not MPG when we talk about fuel economy. GPHM works out like we expect, but MPG can be tricky and you can easily fool yourself.

Why does this happen? Well, it is because the two measures are thinking about taking different things as givens or fixed. With miles per gallon (MPG) you are thinking about using a fixed amount of gas and seeing how far you can go. The idea is to talk about the range you can get with a given amount of gallons.

With gallons per hundred miles (GPHM) you are talking about going a fixed distance and seeing how much gas it will use up doing it. Here you are talking about the fuel usage that it will take you to cover a fixed distance.

Now we can see the root of the problem when we try to use MPG for fuel economy. MPG assumes that you are going to use a fixed amount of gas and tells you about the different ranges different cars could get. But assuming you will use a fixed amount of gas is wrong. We want to go a certain distance. We don't say "I will drive until my car uses up 10 gallons." We say "I will drive to work (which is a distance of 10 miles away)." We should use GPHM to talk about fuel economy because the whole point of saving on gas is not to use a fixed amount of gas, but to change the amount and make it lower.

If you want to read more about this, I wrote about it before and the experts explain it really well here. As always, Wikipedia has useful information. And here is a handy calculator you can use to make conversions.

Run Your Diesel on Used French Fry Oil

Watch as the Mythbusters take used vegetable oil that had been frying up French Fries. Then they do nothing to this oil except filter it to remove chunks. Then they put it in a diesel car with a stock, unmodified engine. The car not only ran, but it got 3.33 GPHM! The same car with normal diesel fuel got a slightly better 3.00 GPHM. Don't believe it? Watch the video!

How to Change Your Own Oil Filter

Your car's engine depends on three filters: the oil filter, the air filter and the gasoline or fuel filter. These keep the engine's "lifebloods" of gas, air and oil clean. Dirty clogged oil filters will result in a bigger pressure drop across them, lowering the oil pressure in the engine. If the pressure loss is too great, oil filters are designed with a bypass value that opens and lets unfiltered oil through. Why? Because dirty oil is better than not enough oil. Loss of sufficient oil pressure can destroy the whole engine. The pressure drop across the oil filter goes up with engine RPM. At very high RPM, say around 4000 RPM, the bypass valve will normally be open due to the large pressure drop at this RPM. Dirtier filters have lower RPM thresholds for opening the bypass. Thus with a dirty filter, every time you rev up your engine you may be letting a shot of dirty oil through.

Dirtier oil is more viscous and the particles of debris in it may wear directly against the moving metal in the engine. This increases engine friction, which lowers fuel economy. So clean oil filters can help get better mileage. You can change your own oil filter and save some money. It is really easy. The video shows how. Watch and learn!

The video below has the part about changing the oil filter. The video above is the introduction and also shows how to change your own oil. If you want, go ahead and buy a K&N HP-1010 Oil Filter from Amazon now!

What Does Engine Oil Do?

The picture shows that sometimes we need friction so we don't go sliding out of control. One place where we do not want friction is in our engines. Engine oil is there to lubricate the metal surfaces and get rid of friction. In a properly working engine, a thin layer of oil separates all metal parts so that there is no metal-metal contact. Instead we find metal-oil-metal contacts. But reduce friction is not all that oil does.

Oil also helps to cool the engine. There are places where the water cooling system just can't reach, like down in the crankcase. Oil gets in these areas and removes the heat. Another role of oil is to help the piston ring seal the combustion chamber or head off from the crankcase. Oil also scavenges tiny metal particles which are worn off when engine surfaces work against each other. These particles are then removed from the oil by the oil filter. Acids can be formed by chemical processes occurring in the combustion of fuel. All gasoline has at least a small amount of sulfur in it. This sulfur can react with water (brought in with the air) to produce sulfuric acid. The sulfuric acid is dissolved in the oil, which has acid neutralizers in it.

IEA Economist Warns about World Oil Supply

Ever wondered if maybe oil prices and therefore gas prices will stay high forever? Today is not like 10 years ago: gas is expensive. The International Energy Association is warning us that gas may never be cheap again. In fact, it could get worse. This is due to a phenomenon known as peak oil. Due to the fact that all of the best oilfields are now used up, we have to get out oil from lower quality ones. The result is not that we are running out of oil, but that the rate we can get it up from the ground is going to go down. Imagine that you have a huge tank of water so there is no trouble with the amount. Now imagine that you can only get the water out through a pinhole. Although you have an unlimited supply, the tiny amount available per day will cause problems. The same thing might be about to happen with the world's oil. We will have huge, practically unlimited amounts of oil in the ground, but we will only be able to pump up a trickle each day.

Turn the Gas Nozzle to Get Every Last Drop

Here is a tip about how to get a little bit of free gas every time you are at the pump. The idea is to turn the gas nozzle upside down before and after filling up to make sure that you drain out any leftover gasoline. It won't save you much more than a cup or two of gas, but you may as well get everything you can.

Brickley Engine - Less Friction, Better Mileage

Friction in the engine itself lowers your car's gas mileage. Instead of begin converted to useful work, some of the energy in the fuel is wasted in the form of heat or noise. Mainly heat. The Brickley engine design aims to rearrange the cylinders and crankshaft arms to reduce this friction. A Brickley engine is an internal combustion engine with specially connected pistons that move along paths to a very high tolerance. Because the piston stroke is defined to a couple thousands of an inch, the piston skirts can be eliminated or reduced. So far this engine exists only as a patent. I doubt there are working models. Not to say I doubt they will work, just that there is still no prototype. Apparently the Brickley design can eliminate 35% of the engine friction. This could give a 15% to 20% increase in vehicle mileage.

One other interesting bit of information was a list of components and their contribution to friction in a typical engine. Here is the breakdown of engine friction by part according to Mike Brickley, the engine designer:

Research attributes the following approximate amounts to the various components: crankshaft 18%, connecting rods 15%, accessories 10%, camshaft 15%, piston rings 21%, piston skirts 21%.

Engine Friction Breakdown

Component	Friction
Piston Rings	21%
Piston Skirts	21%
Crankshaft	18%
Camshaft	15%
Connecting Rods	15%
Accessories	10%

Nissan Leaf Electric Car

Nissan recently announced their new no emissions electric car. Called the LEAF, it is scheduled to be launched in late 2010 in Japan, the United States and Europe. It is a medium-sized hatchback and can seat five adults. Lithium ion cells deliver 100 horses to the electric motor giving a driving range of 100 miles on a full charge with a top speed of 90 mph. Charging time takes approximately 8 hours on a standard 200V outlet. The US market price is expected to be about $30,000 so not a cheapie.

Solar Golf Cart Conversion Kit

Ever wanted to convert a golf cart to use solar power? Here is a kit you can use to do just that. It seems that putting a solar panel on the roof of a golf cart increases the range by 30%. So if you ever wanted to do the commute in to work by golf cart but ran out of charge 70% of the way there, here is your big chance!

Lightning Hybrids

I found these pictures of a futuristic amphibious car that adjusts its wheels for driving on land, ice or water. Following up on it, I found Lightning Hybrids an automotive research and development company that is designing two high fuel economy models, the tricycle LH3 and the normal quad wheelbase LH4. This company is an example of the future that Detroit should have taken.

The LH4 will get 100 miles per gallon. That is 1.00 GPHM or 1 gallon per hundred miles. Read this website to learn about why GPHM is better than using MPG for fuel economy numbers. It is a sporty little number, able to go 0 to 60 in 5.9 seconds. There is room to seat four people. The price tag will be in the $40,000 to $60,000 range, so they are not exactly what you would call cheap. According to the plan, they will be on sale in 2010.

Gas Guzzler Tax

Cars in the US that do not get at least 22.5 miles per gallon have to pay a Gas Guzzler Tax. This tax is the Fed's way of incentivizing the automakers to improve fuel economy. The tax was established in the Energy Tax Act in 1978. It only effects cars. SUVs, pickup trucks and minivans are exempt. You do not have to pay this tax. The automaker (or importer, in the case of foreign vehicles) normally pays the IRS directly. The fuel economy sticker on the window of new vehicles will show the amount of the tax, in case you are interested. The image included with this post demonstrates the Gas Guzzler Tax in the sticker. It is the number located in the lower left.

Remove Side Mirrors for Better Aerodynamics

I found this video at ecomodder.com. They have a website that has interesting ideas on modifications you can make that will save on gas and help the environment. Aerodynamic drag created by the side mirrors protruding out from the car body can be significant. Here you can see how the side mirror has been replaced by a digital video camera! The video says all of the parts needed were bought on eBay. There are step by step instructions for how to do the replacement. Talk about clever. This gives sleek aerodynamics without giving up the ability to see behind you!

Gallons per Hundred Miles or GPHM

Have a look at this New York Times Year in Ideas article, which talks about a new and better way to measure the fuel economy of our vehicles. They suggest we use gallons of gas used to go a hundred miles instead of the traditional miles per gallon. The old way (MPG) tells us how far we can go on a certain amount of gas. The new way (GPHM) tells us how much gas we use to go a certain distance. So why the change? What is wrong with the old way?

Well, there is nothing wrong with it, but it can be very misleading. Basically the old system (MPG) is set up for calculating the range of a vehicle given the amount of gas available. You multiply the amount of gas you have by the MPG number to get the miles you can go. But in the world of fuel economy, we want to ask the opposite question. We want to know how much gas a vehicle will use to go a known distance. Using MPG as a fuel economy rating can give surprising results.

For example, consider a family (call them the Jones') that has a Ford F150 pickup truck that gets 10 miles per gallon. Their neighbors (the Smiths) have a Prius that gets 40 miles per gallon. We pretend that the two families drive these vehicles exactly 10 000 miles in the year 2008. How much gas did each family use up? The Jones' burned through 1000 gallons of gas while the Smiths used 250 gallons.

Okay, now imagine that each family tries to improve the gas mileage of their vehicle. They maintain the tire pressure at the correct value, replace the air filters and have a four-wheel alignment done. As a result, they each enjoy a 3 MPG increase in mileage. Now the Jones' get 13 MPG with their F150, and the Smiths get 43 MPG. In 2009 they again each put 10 000 more miles on their vehicles. How much gas did they burn up in 2009? The Jones family used 769 gallons while the Smith family used 233 gallons. Year over year, the Jones family saved 231 gallons but the Smith family only saved 17 gallons!

This is the problem with using miles per gallon (MPG) to measure fuel economy: the same increase in MPG (in our example 3 MPG more) does not mean the same amount of gas saved. The amount of gas saved depends on both the MPG number and the change in the MPG. Having to think about both the number and the change is unnecessarily complex. Using gallons per hundred miles lets us use just one number again. Let's see the example again, but this time using GPHM.

In 2008, the Jones' Ford F150 used 10 GPHM, and the Smith's Prius used 2.5 GPHM. After the mechanical tuneups, in 2009 the numbers were 7.7 GPHM for the Jones' and 2.33 GPHM for the Smiths. Now you can see the big drop (2.3 GPHM) for the Jones' compared to the tiny (0.17 GPHM) gain made by the Smiths.

So think about fuel economy in gallons per hundred miles (GPHM) instead of miles per gallon (MPG) and you will have a better idea of what is really going on!

Cash for Clunkers Ford's Hero

General Motors has received a lot of scorn for converting itself into "Government Motors" but we must remember that Ford has also needed Federal help to stay afloat. Whatever you think of the Cash for Clunkers program, the beancounters at Ford like it. This is the quote that says it all (from the article in the link):

We were having a good month — and Ford's been having some good months lately — but the (clunkers) program really put us over the top for sure.

The bottom line is that the US auto industry is suffering all around. Without the Feds stepping in to save the day, all Detroit would be underwater. If you ask why, I will tell you that one of the biggest mistakes Detroit made was ignoring fuel economy. The oil price spike was big news, but over the last years we have seen consistently high gasoline prices. It looks like this will be a constant problem in the future. The price of oil is still historically high and could easily go higher. Detroit has to wake up and start making cars that sip gas at a rate that people can afford to pay.

Is Premium Gas Worth Premium Price?

Here is another analysis from MoneyTalksNews on the issue of using a high octane gasoline and paying extra for it. Here at Save on Gas we think the take home message is found at the 44 second mark in the video "Using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit". Watch and see for yourself!

If It Is Possible to Get Better Mileage, Why Don't the Automakers Do It?

Here is a video which asks the question if it is so easy to improve gas mileage, why aren't the big automakers already doing it? The video says it is because the automakers have a stake in the big oil companies. So they work something like the laser printer industry. They sell the cars (or printers) but also make money on the gas (or refills). Anyway, watch and see for yourself.

Whatever you think about the automakers and big oil, one thing is for sure: don't let this be an excuse for not trying to save on gas!