Does a 100 mpg car really make sense?

[Roxanne Appleby]

California congressman Dan Lungren asks in an op-ed, "What would happen if the United States were to offer a $1-billion prize for the first American automaker to sell 60,000 midsized sedans that could travel 100 miles on one gallon of gasoline? It wouldn't be a panacea for our energy problems, but it would stimulate the development of viable technologies to reduce oil consumption while we develop alternatives to petroleum. Competition for a prestigious prize is far more likely to get results than government programs aimed at anticipating and funding 'winners.' Although occasionally effective . . . all too often such subsidies are given to the politically influential, not the meritorious. But prize money is paid out only when the goal is achieved."

I believe that Lungren has a poor understanding of both markets and technology. Current internal combustion engines extract just shy of 40 percent of the chemical energy that exists in a gallon of gas. Marginal improvements can be expected in the future, but the laws of thermodynamics prohibit reaching 100 percent.

That said, it is possible today to build 100 mpg car. It would be very small and aerodynamic, weigh under 1,000 lbs, and be capable of going 70 mph or so running flat out. It would get blown around in strong winds, and would not really be safe sharing the road with today's big trucks.

Given these facts, it is silly to discuss a $1 billion prize. We could have these cars right now with no prize. We could adopt a system that relies more on rail and less on trucks for long distance freight, so those cars could use the roads safely. If gas was $6 or $10 a gallon and there was no alternatives we probably would have such a system. It's actually kind of an "elegant," aesthetically satisfying scenario. But that is just my opinion, not some "metaphysical constant."

For example, it might make more a lot more sense to replace gas stations with "battery-change stations," where electric cars that look just like current cars (instead of 100 mpg cars) would pull in every 150 miles or so, pull out one battery, leave it for recharging and insertion later into another car, and insert a newly recharged battery someone else had dropped off earlier. This could all happen automatically – you back up the changer-thingie and it does all the work. The electricity would come from abundant, increasingly efficient and safe nuclear plants, or possibly some other centralized source capable of providing the magnitudes of energy required by an industrial civilization.

This is a plausible future model that requires no technological leap, just a different infrastructure. There may be others. If the future ends up looking anything like this, people will look back and smile at the quaintly misguided congressman who offered $1 billion of the taxpayers' money chasing a chimera.

 

[dr_mabeuse]

This is a plausible future model that requires no technological leap, just a different infrastructure. There may be others. If the future ends up looking anything like this, people will look back and smile at the quaintly misguided congressman who offered $1 billion of the taxpayers' money chasing a chimera.

Well, they had that prize for man-powered flight across the English Channel and someone accomplished that, but you're right. This isn't a solution.

But then I don't think it's supposed to be a solution. It's a publicity stunt to suggest that there might be a better way for the government to help solve the energy crisis than by just putting Big Oil in charge of policy and letting the Almighty Marketplace work its magic.

A billion dollars is about what it costs to maintain our troops in Iraq for 6 weeks. Call me a dreamer, but I'd rather see that money spent on alternative energy research at home. Let the government do it and fuck the marketplace already. They've had 30 years to come up with an alternative and haven't done squat.

 

[capecodmercury]

The annoying thing is that viable alternative energy sources and methods are available now which could greatly reduce our dependency on the Middle East powder keg. Did anyone see that 60 minute piece on sugar cane based ethanol a few months ago? Here is a link to a transcript. http://www.e85fuel.com/news/050706-60minutes.php
The Brazilian government made a concerted effort years ago to wean Brazil from foreign oil and managed to do it by building up an infrastructure to support flex fuel vehicles. Today they are sitting pretty while oil worries ravage our economy and my savings account.

I know we are not Brazil and have a much bigger oil dependency, but the one truth that comes out of this story is that we are never going to imporve the situation until we get off our hands and start to take action. An idea to help may not be perfect, but the question that needs to be asked is whether it will improve the situation to any measurable degree. If the answer is yes, then we need to start implementing them while the perfect solution is sought.

 

[impressive]

My hybrid self-charges its battery using the energy generated from the heat of braking.

*shrug*

The spouse, who works for the the U.S. Dept. of Energy, tells anyone who'll listen that the industry is simply not going to change its infrastructure until every last bit of fossil fuel is gone.

 

[rgraham666]

The spouse, who works for the the U.S. Dept. of Energy, tells anyone who'll listen that the industry is simply not going to change its infrastructure until every last bit of fossil fuel is gone.

And then, of course, it will be too late.

 

[Roxanne Appleby]

My hybrid self-charges its battery using the energy generated from the heat of braking.

*shrug*

The spouse, who works for the the U.S. Dept. of Energy, tells anyone who'll listen that the industry is simply not going to change its infrastructure until every last bit of fossil fuel is gone.

Your hybrid can only reclaim a small portion of the energy that is used accellerating up to speed, and none of the energy it used cruising along once it was up to speed. It's a neat, worthwhile feature, but only a marginal increase in efficiency.

We won't "pump every last bit of fossil fuel." We may pump every last bit that is very easy to pump, which is not more than half. At that point the cost per barrel gets high enough so that alternative scenarios like the one I describe become more cost effective. And thus more profitable for the companies that adopt them, which very likely will have names like "Exxon," "Shell," and "BP." Maybe Westinghouse and Edison, too (nuke plant builders and operators). (Why do people always assume that big corporations are brainless and will just keep walking into brick walls like some comedy scene automaton? They [managers and stockholders] don't care how they make money, so long as they make money. I'm talking about transitions that happen over a few decades.)

To put that another way, the marketplace is indeed almighty, and will provide a solution without any assistance from wise and benevolent politicians who know best how to solve all the world's problems. (Please pardon my sarcasm.)

"Every individual necessarily labours to render the annual revenue of the society as great as he can. He generally neither intends to promote the public interest, nor knows how much he is promoting it... he intends only his own security; and by directing that industry in such a manner as its produce may be of the greatest value, he intends only his own gain, and he is in this, as in many other cases, led by an invisible hand to promote an end which was no part of his intention. Nor is it always the worse for society that it was no part of his intention."

I have much more faith in this dynamic than any that involves politicians and rent-seeking "research entities," described by the sentence that concludes this quote: "I have never known much good done by those who affected to trade for the public good."

 

[impressive]

Your hybrid can only reclaim a small portion of the energy that is used accellerating up to speed, and none of the energy it used cruising along once it was up to speed. It's a neat, worthwhile feature, but only a marginal increase in efficiency.

I wasn't claiming it's the be-all-and-end-all, but I do consider it more than a "marginal" increase in efficiency when I've nearly tripled my gas mileage & can travel over 500 miles on a (10-gallon) tank of gas.

There are other sources of heat which could be used to charge a battery and add to the amount reclaimed by breaking -- if we'd just take advantage of them.

As for the fossil fuels -- industry is going to maximize its investment in the current infrastructure before converting to something else, even if that means depleting our resources.

 

[Roxanne Appleby]

I wasn't claiming it's the be-all-and-end-all, but I do consider it more than a "marginal" increase in efficiency when I've nearly tripled my gas mileage & can travel over 500 miles on a (10-gallon) tank of gas.

There are other sources of heat which could be used to charge a battery and add to the amount reclaimed by breaking -- if we'd just take advantage of them.

As for the fossil fuels -- industry is going to maximize its investment in the current infrastructure before converting to something else, even if that means depleting our resources.

All the innovative marginal increases in efficiency are wonderful, but they must be kept in perspective.

Yes, industry will maximize its investment. It (we) will pump (deplete) all the easy-to-get oil. It takes massive new investments to pump and refine the hard-to-get stuff (which includes more than half of all the world's oil). Decisions to make those investments or not will be balanced off against investing in alternatives, like the one I describe, or some other one that can provide the magnitudes of energy needed at a competitive price. New investments will be made in the one that delivers the best return over the life of the investment. The transitions will happen over a few decades.

 

[R. Richard]

As has been pointed out, hybrids are not really all that efficient. In addition, the batteries in a hybrid will not last forever. The replacement cost for a new set of batteries will send a lot of hybrid cars to the junkyard rather early on.

The same thing will happen with electric cars. The idea of a "recharging station" is wonderful, until you realize that some of the batteries the recharging station pulls out will not be reusable. The "cheap" electric power will suddenly become rather expensive.

There is no way that anyone is going to build a 1000 pound mid sized sedan. There are 1200 pound Porsche Spyder replicas currently on the road. The replicas can be home built for $20K to $30K, but they have wind stability problems at high speeds. There are $500K and up cars that have no problems at up to 200 MPH. HOWEVER, the air management that allows the high speeds does not come cheap.

The fans of public transportation have obviously never ridden a subway system, such as the NYC subways. Such systems are reasonably efficient and cheap. However, they are uncomfortable and dangerous. Some of the people who ride the public transportation systems need to be in a nental hospital, not roaming about.

 

[Roxanne Appleby]

As has been pointed out, hybrids are not really all that efficient. In addition, the batteries in a hybrid will not last forever. The replacement cost for a new set of batteries will send a lot of hybrid cars to the junkyard rather early on.

The same thing will happen with electric cars. The idea of a "recharging station" is wonderful, until you realize that some of the batteries the recharging station pulls out will not be reusable. The "cheap" electric power will suddenly become rather expensive.

There is no way that anyone is going to build a 1000 pound mid sized sedan. There are 1200 pound Porsche Spyder replicas currently on the road. The replicas can be home built for $20K to $30K, but they have wind stability problems at high speeds. There are $500K and up cars that have no problems at up to 200 MPH. HOWEVER, the air management that allows the high speeds does not come cheap.

The fans of public transportation have obviously never ridden a subway system, such as the NYC subways. Such systems are reasonably efficient and cheap. However, they are uncomfortable and dangerous. Some of the people who ride the public transportation systems need to be in a nental hospital, not roaming about.

R, the costs of the "unuseable" batteries will all be included in the total. I'm talking about a whole new model here. The batteries would be standardized. I do expect marginal increases in battery technology and this will lower costs and increase range, but the system I describe is possible without these.

You can build a 1,000 lb sedan, but as I say it does not look anything like today's 3,000 lb + cars. Picture a 150 cc motorcycle drivetrain with a very lightweight body and interior build around it. Lots of synthetics, fairly spartan, aerodynamic, etc. At 70 mph the motor is running flat out. In airplane terms it would look more like an ultralight-on-steroids than a Piper Aztek. Not quite as skeletal and spartan as an ultralight, but that image points you in the right direction.

 

[oggbashan]

European and Japanese car makers have built cars that could run at 100 miles per Imperial gallon with careful driving.

In the 1960s the RAC (Royal Automobile Club) used to organise events on public roads to find cars that could do high miles per gallon. The drivers were specialists that, with help from specialist tuners, could make a normal car with an average consumption of say 35 mpg do 55 mpg over a 1000 mile course. Small cars such as the original Mini of 848cc would record 75 mpg in these events. The Citreon 2CV with the small engine could beat that with the right driver.

I think that the Daihatsu 3 cylinder diesel Charade could achieve 65mpg without the tuning or special driving skills. The Honda 360 produced nearly as good figures.

BUT... speed, comfort and acceleration were inadequate compared with normal cars. Driving solely to achieve high mpg would irritate almost every other road user. Cruising speeds were in the low 40s in a high gear and all cars were stick shift because automatic boxes add drag, weight and were/are less efficient at matching vehicle speed to fuel consumption than a trained human driver.

There are a number of ways to increase a standard car's fuel consumption. The most obvious are higher than normal tyre pressures; reducing weight wherever possible e.g. don't carry luggage nor a spare wheel and tools, enrolling driver and passengers with WeightWatchers; reducing drag (no roof rack, no extra lights, keeping all windows shut); and NO aircon which adds weight and uses fuel to operate.

The effort put into preparing any one NASCAR auto could be used to produce a US 100mpg vehicle from a small sedan now.

Og

EDITED FOR PS:

I checked the UK's data tables for cars available to purchase here:

This diesel car has the best fuel consumption tested at 83.1 miles per Imperial gallon on the extra-urban cycle:
Citroen C1 HDi

I think, with anyone driving carefully on a flat Interstate, that car could achieve 100 miles on a US gallon and you can buy it now.

Og

 

[dr_mabeuse]

(Why do people always assume that big corporations are brainless and will just keep walking into brick walls like some comedy scene automaton? They [managers and stockholders] don't care how they make money, so long as they make money. I'm talking about transitions that happen over a few decades.)

To put that another way, the marketplace is indeed almighty, and will provide a solution without any assistance from wise and benevolent politicians who know best how to solve all the world's problems. (Please pardon my sarcasm.)

Which is why the drug companies prefer to sell the expensive treatments for diseases rather than put their research money into finding the cheaper preventions.

All the diseases that have been wiped out by modern medicine have been wiped out by government programs, not by the marketplace. "Public good" isn't always synonymous with "private profit."

I'm one of those people who believes that government can be as much a force for good as private industry, and that there are values beyond Self-Interest and the Profit Motive. One of government's roles is to step in when there's a problem that private industry is unwilling or unable to handle.

I'm no longer in the energy business (I was, at Argonne National Laboratory, where the government did research on nuclear energy and safety that private industry wasn't willing to do), but as far as I can see, all the oil companies have done so far concerning research into alternative energy is make commercials about it. They're making record profits right now. Why should they want to kill the goose that's laying their golden eggs?

 

[Antfarmer77]

When I was a kid, this was back in the mid to late 70's, we were in Canada visiting family, and I remember a newspaper article and the picture with the story was a young man standing between like a '67 Chevelle, all rusted and dented and a patchwork of different colors of paint and a brand new Lincoln MK4. He was a highschool dropout that had been a mechanic all his life ( he was 24-ish as I remember) and the Chevelle was the car he drove to work and the Lincon was the car he had bought, for cash, with some of the money from some big oil company that had purchased the carborator (sp) plans he had developed that got 100+ mpg on the Chevelle. Ok now a '67 Chevelle is no lightweight, and if I remember right, it still had the stock V8. If a four cylinder engine can me made that will propel a car 200+ mph, then surely a 6 cyl. can be produced that can squeeze 100 miles out of a gallon of gas. But then again, you do the math, if the average car gets 20-25 mpg and gas is $3.00/gal, what will it cost per gallon if a 100 mpg car is mass produced? Big Oil isn't going to lose any money.

 

[R. Richard]

BUT... speed, comfort and acceleration were inadequate compared with normal cars. Driving solely to achieve high mpg would irritate almost every other road user. Cruising speeds were in the low 40s in a high gear and all cars were stick shift because automatic boxes add drag, weight and were/are less efficient at matching vehicle speed to fuel consumption than a trained human driver.
Og

Og:
What you have stated is the real key. Yes, a very small car [one or two passenger] with no luggage space and VERY few amenities can produce very high mileage figures. However, that car is not a sedan which would carry at least four passengers. If you add four passengers to a small car, you add perhaps 800 pounds of weight. An additional 800 pounds of weight will impact even level road gas mileage and will KILL acceleration.

It is actually dangerous to drive a very underpowered car on the public highways. First, other drivers bcome annoyed and take stupid risks. Second, a 1,000 pound sedan with four 200 pound passengers will simply not climb a long, steep hill in anything other than a first type gear ratio. Third, a 1,000 pound sedan with four 200 pound passengers will simply not be able to accelerate in a reasonable manner once it is forced to slow down.

The problem that many do not see is torque. A 150cc engine is about nine cubic inches. A nine cubic inch passenger car engine might produce 10 foot pounds of torque. A motorcycle that weighs 250 pounds with rider can produce fairly sprightly performance, mainly because it can be geared way down and then use the ability of such a small engine to rev so that road speeds are maintained. If the motorcylce weight goes up to 350 pounds because of a 250 pound rider, the performance dies! A sedan with an all up weight of say 1,800 pounds is a very slow moving road block.

I am an engineer by training and I know what I am talking about here.

 

[oggbashan]

The Polish are no joke:

Beskid 106

What if this had been developed by a major auto manufacturer?

Og

 

[Roxanne Appleby]

Which is why the drug companies prefer to sell the expensive treatments for diseases rather than put their research money into finding the cheaper preventions.

All the diseases that have been wiped out by modern medicine have been wiped out by government programs, not by the marketplace. "Public good" isn't always synonymous with "private profit."

I'm one of those people who believes that government can be as much a force for good as private industry, and that there are values beyond Self-Interest and the Profit Motive. One of government's roles is to step in when there's a problem that private industry is unwilling or unable to handle.

I'm no longer in the energy business (I was, at Argonne National Laboratory, where the government did research on nuclear energy and safety that private industry wasn't willing to do), but as far as I can see, all the oil companies have done so far concerning research into alternative energy is make commercials about it. They're making record profits right now. Why should they want to kill the goose that's laying their golden eggs?

Mab, I'm skeptical about your claim regardging drug development; also, the government is deeply enmeshed in drug research of all kinds so I'm not sure that a meaningful claim can be made one way or the other about it - it's kind of like figuring out which cars are "domestic" given all the mixed content.

On your broader point about the ability to do good, the problem is that government is not run by philosopher kings who can predict all the answers. Unlike markets, effective self-correcting mechanisms do not exist. "Rent seeking" is rife; self-interest is just as determinative of goverment action as of private sector action (Public Choice theory), but it masquerades behind a facade of altruism and "public good."

Regarding oil companies researching alternative energy, see my posts above. Of course they want to maximize the return on existing investments, but those won't last forever. New investments will be needed. But the existing sources won't run out tomorrow, either, and there is a lot of uncertainty regarding alternative technologies. It may well be premature to make huge investments in alternatives, given that the existing resources and technologies will suffice for the next 40-80 years. The change will come gradually as described in my previous posts, over a few decads. During that period all the alternatives will be weighed and the ones that promise the most return will be adopted. Not coincidentally, given a competitive free enterprise system, those will also be the ones that deliver the best value to customers. On what other basis would you want to see decisions made? Would you rather pay more or less for a product, whether it's food or housing or transporation? To the extent government has a role it will be the traditional one of ensuring that the costs of any of the competing new systems are not "externalized," the competition gives the correct and honest best solution for our energry future.

 

[oggbashan]

Og:
What you have stated is the real key. Yes, a very small car [one or two passenger] with no luggage space and VERY few amenities can produce very high mileage figures. However, that car is not a sedan which would carry at least four passengers. If you add four passengers to a small car, you add perhaps 800 pounds of weight. An additional 800 pounds of weight will impact even level road gas mileage and will KILL acceleration.

It is actually dangerous to drive a very underpowered car on the public highways. First, other drivers bcome annoyed and take stupid risks. Second, a 1,000 pound sedan with four 200 pound passengers will simply not climb a long, steep hill in anything other than a first type gear ratio. Third, a 1,000 pound sedan with four 200 pound passengers will simply not be able to accelerate in a reasonable manner once it is forced to slow down.

The problem that many do not see is torque. A 150cc engine is about nine cubic inches. A nine cubic inch passenger car engine might produce 10 foot pounds of torque. A motorcycle that weighs 250 pounds with rider can produce fairly sprightly performance, mainly because it can be geared way down and then use the ability of such a small engine to rev so that road speeds are maintained. If the motorcylce weight goes up to 350 pounds because of a 250 pound rider, the performance dies! A sedan with an all up weight of say 1,800 pounds is a very slow moving road block.

I am an engineer by training and I know what I am talking about here.

I understand what you are saying.

However tax regimes (and high gas costs) in Europe have favoured very light cars for over 80 years.

The Austin Seven of 1922 was designed for two adults and two children with a 750cc engine. There were jokes about 'what adults are that light?' but Austin 7s frequently carried four adults. The consequence was that the wheelbase altered as it rolled in a corner and the brakes might stop it eventually but in the 1920s no one had heard of Ralph Nader.

The Citroen 2CV had the crash resistance of a wet cardboard box but carried French families and their luggage for generations with very little fuel use per mile.

Both cars were BETTER than some of their competitors that were even lighter and flimsier. The Goliath 'Kommisbrot' was a three wheeler with a wickerwork body. The German-assembled Austin 7 killed it.

Most European cars are smaller than US compacts yet carry families. The Mini used to carry 4 adults. I had an 848cc Austin Minivan. On one occasion I carried myself, no lightweight, and five student nurses for 35 miles at an average speed of 50 mph, up and downhill with no trouble except slightly more frequent gearchanging than would have been required if I had been on my own. Conservation of momentum up and down hills, engine designed to be high revving, and the driver matching gear to load conditions can mean a reasonable speed with a load.

Og

 

[R. Richard]

I understand what you are saying Og. It is possible to have a light car with a small engine and it will function and even carry more weight than the designers intended.

However, a light, small engined car with a heavy load is frequently unsafe and a road hazard. In addition, the same light. small engined car with a heavy load does not get anywhere near 100 miles per gallon [no, we are not talking about your Imperial gallons here, but the smaller US gallons.] It is not impossible to ride a 600cc motorcycle very conservatively and get perhaps 60 MPG, but that is just one passenger.

A very long time ago, I read of an event called the Woods River Mileage Marathon. Cars were able to achieve mileage over OVER 100 MPG. How it was done was with ultra light weight cars, tire pressures over 100 PSI and very strange driving tactics. A car was accelerated up to maybe 25 MPH in top gear at full throttle. Then the car was allowed to coast down to maybe 15 MPH and then accelerated at full throttle again up to maybe 25 MPH in top gear. It did produce mileage over over 100 MPG, but you would die in a traffic accident if you tried it on public roads.

 

[oggbashan]

The Citroen C1 is designed to carry four people:

Review

There is a deliberate error in the review. The wheelbase is 3.4 metres, not 34!

The RAC road trials produced remarkably high mpg. If a diesel version of the Citroen C1 was driven as if for those trials I think it could get close to the 100 miles from a US gallon, possibly even four up. At what speed? Probably about a steady 55 mph because most European cars are designed to be at their most fuel-efficient at that speed to meet European fuel consumption tests.

The C1 Diesel is the most fuel-efficient car sold in the UK. In other European markets and Japan there are cars with even better figures but we Brits won't buy them.

Og

 

[oggbashan]

...[no, we are not talking about your Imperial gallons here, but the smaller US gallons.] It is not impossible to ride a 600cc motorcycle very conservatively and get perhaps 60 MPG, but that is just one passenger.

I have a 1957 BSA Bantam 125cc motorcycle. With my 17 stone on it I get 95 to 100 mpg. I had a 1955 Ariel 350cc Red Hunter. I used to get 85 mpg and better on a steady run at 50 to 60 mph. One of my daughters had a Honda moped. She is much lighter than I am. In London traffic she averaged 110 to 120 mpg but was limited to 30 mph, the speed limit in the built up areas she crossed. All those figures are for the Imperial gallon of 4.54litres.

One aim of UK motor manufacturers in the 1950s was to build a small car, a modern version of the Austin Seven, that would carry two adults and two children at fifty miles per hour using petrol at 50 mpg. The Morris Minor, Standard 8, and Austin A30/35 all came close to that standard with the lower octane fuels then available here.

The Polish Beskid 106 mentioned above would have been much better than the Citroen.

Og

 

[rgraham666]

Um, Roxanne. There is a way that governments can be controlled, at least here in the West.

It's called 'voting'.

 

[impressive]

Um, Roxanne. There is a way that governments can be controlled, at least here in the West.

It's called 'voting'.

The people who cast the votes decide nothing. The people who count the votes decide everything. (~ Stalin, attributed)

 

[R. Richard]

I have a 1957 BSA Bantam 125cc motorcycle. With my 17 stone on it I get 95 to 100 mpg. I had a 1955 Ariel 350cc Red Hunter. I used to get 85 mpg and better on a steady run at 50 to 60 mph. One of my daughters had a Honda moped. She is much lighter than I am. In London traffic she averaged 110 to 120 mpg but was limited to 30 mph, the speed limit in the built up areas she crossed. All those figures are for the Imperial gallon of 4.54litres.

I used to ride motorcycles myself. First, as you have pointed out, your mileage figures are for the Imperial gallon, the US gallon is some .833 of an Imperial gallon. I don't know how traffic is in the UK, but if a US rider mainatains a steady speed of 50/60 MPH, he has suicdal tendencies. Here in the colonies it is necessary to move faster than the traffic so that the rider choses the risk. Mileage does not benefit from higher speeds and the sometimes necessary hard acceleration necessary to keep out of trouble.

One aim of UK motor manufacturers in the 1950s was to build a small car, a modern version of the Austin Seven, that would carry two adults and two children at fifty miles per hour using petrol at 50 mpg. The Morris Minor, Standard 8, and Austin A30/35 all came close to that standard with the lower octane fuels then available here.
Og

I drive a 1957 Porsche Speedster. The engine is a VERY non-stock VW unit. I can still get mileage in the mid 30 MPG, if I can drive for long periods at around 30 MPH. The only reason I would ever drive for a long period of time at 30MPH is that I am trying to convince some young lady to stop at a motel along the way. [OK, OK! Most of the broads I drive with do not begin to merit the title lady, but I am working for a goal here.] A light, steamlined car, with an engine set up for mileage could possibly achieve 50 MPG [US gallons] at low, steady speeds. However, 100 MPG, no way!

 

[oggbashan]

First, as you have pointed out, your mileage figures are for the Imperial gallon, the US gallon is some .833 of an Imperial gallon.

... A light, steamlined car, with an engine set up for mileage could possibly achieve 50 MPG [US gallons] at low, steady speeds. However, 100 MPG, no way!

The figures for the Citroen C1 diesel, using your figure of .833 of a UK gallon, work out at 68 mpg for Extra-Urban driving.

What I am trying to say is that average European family cars are already designed to achieve much higher mpg than the average US model.

There are two reasons:

1. The cost of gas (petrol) over here is so much higher and has been for years so it is a good selling point for a car to have good mpg.

2. The size, weight and engine capacity of the average European car are much smaller than the average US car yet the people carrying capacities are comparable and the speed is similiar or faster.

I appreciate that European and US driving conditions/distances are different yet we get and expect much higher mpg than you do because fuel costs so much. Tax regimes here have almost always been against the use of large engines. The tax on a Hummer in the UK is high. In some European countries the annual tax difference between a small engined car and a Hummer would buy another car in about three years...

The various governments in Europe make fuel economy attractive with tax breaks for the owners.

Og

 

[Weird Harold]

That said, it is possible today to build 100 mpg car. It would be very small and aerodynamic, weigh under 1,000 lbs, and be capable of going 70 mph or so running flat out. It would get blown around in strong winds, and would not really be safe sharing the road with today's big trucks.

Actually, I don't believe that it is possible to build a 100MPG car today -- at least not one that will meet the safety and pollution requirements imposed by the various governments!

The safety features in modern cars -- crumple zones, soft bumpers, air-bags, seat-belts, etc -- all add weight to the minimum possible weight of a car; ranging from a few ounces for airbags to a few hundred weight for sogft bumpers. Seatbelts add more than the weight of the belt alone, BTW -- the anchor points have to be reinforced and that adds dozens of pounds to the structure.

Emission Control regulations and Efficiency (MPG) regulations are conflicting requirements for the most part -- when the first required emission controls were added to cars in the sixties, average milage was reduced by almost 50%. If the government truly wants 100 MPG cars on the road, the quickest way to get them is to repeal the safety and emissions requirements!

I don't think the public would stand for a repeal of safety or pollution controls, though -- safety and low emissions are bigger selling points than milage for most people.