Category Archives: Automotive History

Which is Cheaper: Gasoline or Ethanol?

ethanolmolecule

Gasoline versus Ethanol

Shown above is a molecule of ethyl alcohol, also known as ethanol.  If you ignite it with a spark, it will burn. This is not rocket science.  (Come to think of it, though, if you use it as rocket fuel, then it is rocket science.)  Gasoline (or petrol, as our friends across the pond like to call it) is a mixture of molecules, most of which look very similar to the one above. If you ignite it with a spark, it will also burn. The difference, however, is the “O“. Gasoline doesn’t have any oxygen atoms. To burn it, you need to supply all of the oxygen from another source. Fortunately, that’s easy to do, since we live in an atmosphere consisting partly of oxygen, and it’s free for the taking.

But this means that for a given amount of fuel, the ethanol will have less energy content: If you burn gasoline, you can use the free oxygen that is floating around. If you use ethanol, then you are paying for some of the oxygen, which you could have gotten for free.

For this reason, I’ve heard many people explain that you shouldn’t use ethanol as fuel, because your fuel mileage will be lower. But that’s not the end of the discussion: If you’re like me, you are really concerned about saving money, and your main concern is which fuel is cheaper.

A Real World Comparison Test

MSPEscanabaI’ve heard many persons express their opinion as to the relative fuel economy, but I’ve never heard anyone actually test it, so I decided to do so myself. I recently had to drive from St. Paul, MN, to Escanaba, MI, to do an FCC Great Lakes Ship Radio Inspection. I drove eastbound using e85, a mixture of approximately 85% ethanol and 15% gasoline, and drove westbound with gasoline (which is actually e10, 90% gasoline and 10% ethanol). For the nitpickers, here are the conditions of the test:

To make sure I was able to purge almost all of the E85 from the system before the return trip, I tested the mileage from St. Paul, MN, to Marinette, WI, short of my final destination. I started with a full tank, and upon arriving in Marinette, I checked the cumulative mileage and then added about 6 gallons. I also added a few gallons in Escanaba, MI, about 56 miles away. When I arrived back in Marinette, I was down to about a quarter tank, at which point I filled with gasoline (actually, e10) for the trip home. So almost all of the e85 had been purged from the system for the trip home.

My vehicle is a 2014 Dodge Journey with the 3.6 liter 6 cylinder engine. The EPA estimated highway mileage is 25 MPG with gasoline, and 18 MPG with e85. The two endpoints have similar elevations (795 feet in St. Paul, versus 594 in Marinette). Winds on the day of my trip were light, and whenever I did see flags moving in the breeze, the prevailing wind seemed to be from the north. So there should be no effect from a headwind or tailwind. I took an identical route both directions, mostly over four lane freeways, but a small portion over county highways suggested by Google. In other words, the driving conditions both directions were more or less identical. The average mileage reading was taken from the car’s computer, which was reset after each fill-up.

The average mileage using e85 was 21.6 MPG. The average mileage using gasoline (actually e10) was 26.4 MPG. As noted above, the mileage with ethanol was lower, since the fuel has a lower energy content. The real question is which fuel is cheaper.

To make the comparison fair, I’ll use the prices at the same station, the one where I bought the e85: The e85 cost $2.229 per gallon. In other words, it cost me $2.229 to drive 21.6 miles, or 10.32 cents per mile. (I actually used a loyalty card, which brought the cost down to $2.029 per gallon, or 9.4 cents per mile).

The gasoline I bought for the return trip cost $3.239 per gallon, since one gallon allows me to drive 26.4 miles, that means I spent 12.3 cents per mile. But in fairness, if I had bought that gas for the eastbound trip at the same place where I bought the e85, it would have cost $3.099 per gallon, which works out to 11.7 cents per mile.

In other words, it was cheaper to drive using the e85: 10.3 cents per mile versus 11.7 cents per mile. In other words, the e85 is 12% cheaper than using gasoline.

It should be noted that these figures are based upon the price at one particular station, a Holiday gas station.  You can view the current prices at this station at this link.  Some gas stations sell e85, but at a much smaller discount over the price of regular gasoline. In fact, I’ve occasionally seeing a station inexplicably selling e85 for more than the price of regular gasoline. Obviously, it makes no sense to buy to buy there. To be economical, the price of e85 needs to be below 21.6/26.4 = 82% the price of regular gas. In my case, the price of e85 was 74% the cost, and thus a clear bargain.

Other Considerations

There are a couple of other factors to keep in mind. Even though the name of the fuel is “e85” the exact blend can vary. During the winter months, the gasoline content is higher, and I have noticed that stations do not adjust the price based upon the exact mix. So during the winter, the e85 might be an even greater bargain.

Also, I have not measured it, but I have noticed that when I have a mixture that is around 50% ethanol and 50% gasoline, I don’t notice much mileage difference between it and 100% gasoline. So even though the energy content is lower, the actual effect on mileage might not be linear. It would be interesting to repeat this experiment with different blends.

I’m not sure of this, but I suspect that for applications requiring more power (such as towing), gasoline would have a greater advantage. But again, I’ve not tested this hypothesis.

And you will certainly have more range using gasoline than you would ethanol. So if cost isn’t an issue, but you need to drive as far as possible before refueling, then you will be able to drive 22% further by using gasoline.

I suspect that ethanol might have a greater cost advantage for high altitude driving. The reason why there is a lower energy content is because the fuel contains oxygen, which is available at no cost from the atmosphere. At higher elevations, the additional oxygen in the fuel might be an advantage.

Precisely because it has a lower energy content, ethanol also increases the octane rating of the fuel, so it is an inexpensive option for use in high compression engines.

Ideas for Young Scientists

If students are looking for an interesting science fair project, I hope my little experiment has given you some ideas. Even if you don’t have a driver’s license, you can recruit your parents to keep track of mileage when driving, and compare different fuels, or different types of driving, to see which is the most economical.

Interestingly, I exceeded the EPA mileage estimates for both fuels. There was a time when the EPA estimates were overly optimistic, but I guess those days are gone.

But Ethanol Will Clog My Fuel Filter!

Someone will invariably claim that ethanol clogs fuel filters, and I want to explain what is really happening.  Alcohol can mix with both water and gasoline.  Water, by itself, cannot mix with gasoline.  If you have 100% gasoline in your tank and some water is added, it is heavier than gasoline and will settle to the sump at the bottom of the tank, which is below the point where it can be drawn out by the fuel pump.  It doesn’t do any harm there, as long as it stays below the level of the fuel intake.  But it does dissolve dirt, and that dirt has nowhere to go but stay in the water.

Eventually, if water keeps getting added, it will continue to collect.  If it ever gets up to the level of the intake, then this will be a problem, since water mixed with dirt will be going to the engine rather than gasoline.  The fuel filter will clean out the dirt, but the engine will try to burn the water, and water doesn’t burn.

When ethanol was first added to gasoline in the U.S., this meant that it found its way, for the first time, into cars with water in the bottom of the tank.  The alcohol allowed the water and dirt to mix with the gasoline.  The dirt, which may have collected since the car was new, went into the fuel filter, as the filter was designed to do.  This is how ethanol got a reputation for clogging fuel filters.

But now, virtually all gasoline sold in the U.S. contains at least 10% ethanol, and virtually every car on the road has been burning 10% ethanol for years.  Water never gets a chance to build up in the tank.  If there is dirt in the tank, it comes out constantly.  Unlike the time the car got its first tank of ethanol, years’ accumulation of dirt is not coming out all at once to suddenly clog the filter.  So after that initial shock, ethanol actually corrects the problem, and also prevents gas line freeze.  In the days before ethanol fuel, in cold climates, people bought a product called Heet to prevent fuel line freezing.  This consisted either of ethanol or isopropyl alcohol.  Since ethanol is now included in the fuel, this is no longer necessary, and you rarely hear of gas lines freezing.



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Electronic Route Guidance System (ERGS) 1971

1971SepElemElecFifty years ago this month, the September 1971 issue of Elementary Electronics carried a feature describing a proposed system known as Electronic Route Guidance System (ERGS). While it was apparently never adopted, the system was tested in the Washington, D.C. area, and amounted to an early prototype of Google Maps.

ERGS1he system would provide directions to your destination as you drove. It was ultimately envisioned as a nationwide system. The user would enter a 6-digit alphabetical code into the car’s unit. This code could be looked up in a directory (or provided by a person at the destination) and would represent one of up to four million destinations. As he or she drove along, the system would continually give directions of whether to go straight, turn right, or turn left. In many cases, the instructions would alert the driver to take the second right or the third left. Directions would be given on a heads-up display, such as shown at left, or on a unit mounted on the dashboard, as shown above.

This was all done long before the advent of GPS, and the position locating and storage of directions were elegantly simple. To service four million destinations, up to 200,000 intersections would have installed loop antennas under the pavement. Each loop antenna would be connected to a receiver and 2-watt transmitters operating on 170 and 230 kHz. Cars would be equipped with a similar system. As a car drove over a loop, a 230 kHz signal from the pavement would be detected by the car, and this would trigger the car to transmit its destination, in the form of a 25-bit binary code, on 170 kHz. This would be received by the pavement antenna. For each of the 4,000,000 possible destinations, the system would then have locally stored the proper direction to go to get to that destination. The pavement antenna would then transmit that information as a 16-bit signal, which would be displayed on the 16-element display shown at right.  Only the needed segments would be lighted, allowing a wide variety of messages. ERGS2The entire process would take 21.0-24.3 milliseconds. The system used on-off keying with a data transmission rate of 2000 bits per second. When the driver passed over the station closest to the final destination, the display would indicate “END.”

More technical details of the system can be found in this 1969 report of the Federal Highway Administration.

If a driver missed a turn, the system would be automatically self-correcting.  At the next intersection equipped with a loop antenna, the system would show directions to the programmed destination, from that location.



Iowa Scouts Build Car: 1921

1921AprPM2Shown here, in the April 1921 issue of Popular Mechanics are members of Boy Scout Troop 2 of Maxwell, Iowa. While it probably wouldn’t comply with the current edition of the Guide to Safe Scouting, the scouts put together this automobile.

The gears, frame, and axles came from different makes of cars, but they managed to put them together in a perfectly serviceable fashion. The power plant was a damaged stationary engine (or we should say, formerly stationary) which they acquired for $10. The engine was bolted to an old automobile wheel, which transmitted the power to a long shaft, which was in turn geared to a normal drive shaft.

“Speed was sacrificed in favor of reliability,” and the vehicle was capable of 10 miles per hour. The car had recently made a round trip to the Iowa State Fair, where it was said to have created a sensation.



1941 Prices: Western Auto

1941WesternAutoHere’s a snapshot of the cost of living from 80 years ago, on the eve of World War 2, from the April 16, 1941, issue of the Pittsburgh Press, courtesy of this ad for Western Auto Stores.  (For a larger image, from most browsers, click twice on the image.)

According to this inflation calculator, one dollar in 1941 was the equivalent of $18.02 in 2021 dollars. Here are some representative prices, with the modern equivalent in parenthesis:

Western had its own brand of radios, Truetone. A portable, which could operate on battery or household current, sold for $14.45 ($260.39), not including the battery. A single-unit car radio, with pushbutton tuning, could be had for the same price. A three-piece unit sold for $27.95 ($503.66), which included installation. The six-tube set had a chassis that mounted out of the way, with separate control unit and speaker.  Whichever car radio someone bought in 1941, there’s a good chance that they would be taking it inside to listen to when gas rationing meant the car spent most of its time in the garage.

Spark plugs would set you back a quarter ($4.50), but they were guaranteed for 10,000 miles. Fan belts started at 34 cents ($6.13). A new battery for the car would be $4.45 ($80.19) and was guaranteed for two years. A bicycle was $18.75 ($338), but if you needed just a tire, that was $1.62 ($29.20). Tires for the car started at $6.44 ($116.05), but they included a free tube. If you wanted to go fishing, a complete outfit could be had for just 98 cents ($17.66).



1921 Recreational Vehicles

1921MarPM1This early proto-recreational vehicle was shown a hundred years ago in the March 1921 issue of Popular Mechanics. The magazine notes that this vehicle, called an “auto-bungalow” was “the culmination of a movement which had been growing ever since the motor car became a reliable means of transportation. It ancestor was the two-wheeled homemade camp trailer, designed to carry the tents, bedding, and other simple requisites of a two-weeks period of “roughing it” in the woods or at the shore.”

The early RV shown above was not cheap. According to the magazine, the total cost was $16,000. According to this inflation calculator, that would work out to almost a quarter million in today’s money, a figure that’s not surprising, since many top-end RV’s are available today in that price range. The vehicle, including the rear porch, had an overall length of 30 feet. As is apparent, it required an abnormally long overhang at the rear, but the magazine pointed out that this was an advantage, since it put most of the weight on the rear axle, providing better traction and making steering easier. The interior living quarters measured a respectable 8 by 20 feet, which included a kitchenette with ice box, stove, hot water tank, and fireless cooker. It included toilet facilities and 22 incandescent lights powered by battery and generator.

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As is the case today, not everyone could afford such a top-of-the-line luxury RV, and the magazine pointed out a number of options for the more budget conscious. For example, the “20th century prairie schooner” shown at left was constructed at reasonable cost by a Kansas City resident. It was built on the chassis of a popular make of light car, with the wheelbase extended several inches. The even simpler equipment shown to the right 1921MarPM3was designed by a Maine resident at a total cost of $312, including two new tires. This family of six cooked most of their meals on campfires.

 

Modern tent trailer for motorcycle or small car. Amazon photo.

The tent trailer shown below is similar in concept to some modern motorcycle camping trailers. According to the magazine, a number of such trailers, with either two or four wheels, were readily available for purchase, for the benefit of those with “neither the leisure nor the ingenuity to originate and build outfits.”

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1930 Car Radio

1930JanPMIn 1930, this gentleman, Popular Mechanics writer Allen C. Forbes, was undoubtedly the first on his block to have a car radio in his 1929 Nash. It took him two years of experimentation to finally succeed, but succeed he did, and he reported that the set furnished pleasure to himself during the day and to his family when out for an evening ride.

He reported that the biggest problems were ignition noise and lack of a good antenna and ground. Ignition noise was solved by suppressors in the ignition line and a well shielded set. For an antenna, he settled upon a screen mounted under the car’s fabric roof. He reported that with a set of six or more tubes, he could get good loudspeaker volume 100-150 miles away from a station.

Grounding was very difficult, because he used the car’s battery as the A battery, but the car had a positive ground, while the radio had negative ground. The set’s ground connection was not used, and the set was mounted with great care so that no part of the metal chassis or case touched the car chassis. The B and C batteries were mounted in an extra battery box. A plug-in cable was fabricated to facilitate easy removal of the radio from the car.

The radio was an Atwater-Kent model 35 with 3 RF stages, detector, and 2 audio stages. He noted that it was essential that a set with a metal cabinet be used, and that the set needed plenty of RF stages to offset the short antenna. Tet was mounted in the car upside down, and he noted that it was a good idea to solder the tubes into their sockets, especially if the car wasn’t equipped with shock absorbers.

The article appeared in the January 1930 issue of Popular Mechanics.



1961 Philips Norelco “Auto Mignon” Record Player

1961JanEISixty years ago this month, the January 1961 issue of Electronics Illustrated showed this automotive record player, the Norelco “Auto Mignon” (sold in Europe under the Philips name).

The set played 45 RPM records, which were loaded from the front with a “trap door,” not unlike how CD’s are loaded into most car players. The set played through the car radio, and ran off either 6 or12 volts. It retailed for $57.50

You can see a well preserved specimen of the model in this video:

 



1939: No Car Too Old for Radio

1939AugRadioRetailingEighty years ago this month, the August 1939 issue of Radio Retailing offered this suggestion for marketing car radios. By this time, it was natural to have a new radio in a new car. But the creative dealer could create a market by selling new radios to put in old cars.

The demonstration shown here was put together by dealer Crest, Incorporated, in St. Louis. To show that no car is too old for a radio, they installed the latest 1940 pushbutton model in this 1909 Ford. “And out into both commercial and residential districts went the car, attracting crowds by the very contrast between its own ancient appearance and the ultra-modern styling and performance of its accessory.”

The car cost the dealer ten dollars per day, which included the driver, gas, and oil. The canvas sign cost another ten dollars.



1938 Mobile Generator

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From the October 1938 issue of Popular Science, this photo is self-explanatory: For a convenient source of electric power, all you need is a generator on the rear bumper, hooked to the drive wheel with a belt and pulley. It can be used in motion, or when stopped, simply by jacking up the rear wheel.



1968 Police Dash Cam

1968OctPMFifty years ago this month, the October 1968 issue of Popular Mechanics shows this early rendition of a police dash cam.  According to the magazine, the Connecticut State Police had just started using the system shown here. The Sony camera was mounted on the dash, with a small microphone hanging around the officer’s neck. The back seat was taken up by the video recorder and monitor. The system ran entirely on 12 volts, at a cost of “less than $2000.”

The article quoted Sgt. Nelson Hurlburt, who reported that he simply let the tape keep running while on patrol. The tape had 30 minutes of recording time, so if he didn’t catch anything at the end of that time, he rewound the tape and started over. The lens was adjusted three times, at the beginning of his shift, again at 10:00 AM, and then again at dusk. The camera could automatically adjust to changing light levels during the day.

The magazine noted that the videotape evidence made a compelling case to the driver who was pulled over or, if necessary, in court.