100 miles per gallon?

[Eagle43]

Since we have some engineering/computer wizards on this forum, here's a question: Could we not routinely get 100 mpg in our vehicles, even the big ones? If not, why not? Microprocessors can do everything else, why not build an engine and a computer that burns the gas drop by drop? Or one that reuses the waste coming from the burning of the fuel.

These hybrid autos seem to be ok, but they're just a start.

Maybe we've fooled around with oil so long that the answer is hydrogen or something else not even thought of.

I suspect that the answer lies in costs. It would cost way more than oil does and until oil gets up high enough to make it profitable, we won't see it? About the time we have same fuel costs as Europe, expect a breakthrough in technology.

 

[cute fuzzy bunny]

You've hit the nail on the head: costs.

Consider the cost to convert all of the oil burning vehicles in the world to something else. Many busses, trucks and other vehicles have 20+ year service lives and were just bought.

Hydrogen is very expensive to produce. Solar costs are very high but becoming cheaper. A lot of coal and oil is available but costs too much to extract or refine the impurities from.

Electric seems delightful, but a few electric car owners might be dismayed to find that the nice clean electricity they're zapping into their electric cars was produced by throwing a few extra pieces of high sulfur coal into a furnace somewhere a few hundred miles away. Nice job, einstein.

The good news is that technology will create more viable alternatives and reduce costs, bringing more energy offerings to the table at the right price.

I'm more concerned with the pollutants than long term energy options. In 40-50 years when we've decided we've done enough studies to determine that there is a problem with pollution, we'll all be enjoying some fairly disgusting air and water.

 

[Patrick]

I think the answer is methanol. The gas-fueled vehicles we currently have on the road could easily be converted to run on it. The distribution system we have in place can be used for it. And, it's renewable. We just need to get those farmers growing more corn and build a few hundred more distillation plants.

 

[Marshac]

Having gone to WWU, I have a few friends who went through the VRI (Vehicle Research Institute http://vri.etec.wwu.edu/), and have had a few discussions with them on this.

First off, most modern cars with fuel injection basically do burn fuel in the way you mentioned, and direct fuel injection is right around the corner. PCV and EGR basically accomplish what you described by recycling unburned fuel.

Electric cars (like the EV1) really aren't the solution to air quality concerns as most of the US is still powered by coal fired plants, and charging your car actually produces more pollution than a modern 4-cycle gas engine.

Hydrogen powered cars really aren't viable at the moment due to adequate H2 storage capacity (or lack thereof). Hybrids are great for city driving, but you will see the mpg drop off when doing highway driving. The mpg is still good, but keep in mind that they usually have a very small lean-burning engine, so they aren't gos hogs anyways (compare the Prius' 1.5L 51 mpg to the 1.7L Civic HX's 44mpg... not a big difference).

If oil prices maintain their current levels, look for biodiesel to rapidly come onto the scene. Right now you can produce biodiesel for about what petrol diesel costs, but with a $.01 *%*gal tax credit, a producer could possibly gain a $1/gallon tax credit for producing the stuff, allowing biodiesel to be sold at a fairly competitive price.

Regardless, Americans have already proven that they don't care about mpg, and would rather complain about it than buy a more efficient car. How many SUVs do you see driving down the freeway with one occupant? How many guys do you know own a F350, but have never towed anything in their lives? Once attitudes change, you will begin to see real changes in the mpg of cars.

 

[charlie]

Patrick, I read somewhere that methanol has a
negative energy efficiency. That is it takes more
energy to plant, harvest and produce methanol
than you get out. If my recollection is correct
the negative margin is slight, however.

OTOH, there is a root of some kind grown in Canada
that is more efficient .... time to invade Canada?

Cheers,

Charlie

 

[Spanky]

How about a bike? No gas, electricity, coal or any other natural resources are required. It does not pollute the air. It does not take up a lot of room (space or road). It is a good way to exercise.

 

[laurence]

Very good points, all. I would love it if we got into mass transit and bycycles as our main means of transportation, but unfortunately America's love affair with the car has led to communities being built in such a way that you need a car. If you live in suburbia 45 minutes from work, catching the bus might make the commute time two hours, and you can forget about biking unless you are Lance Armstrong. Europeans will have it easier, I think.

 

[cute fuzzy bunny]

Patrick, I read somewhere that methanol has a
negative energy efficiency.  That is it takes more
energy to plant, harvest and produce methanol
than you get out.  If my recollection is correct
the negative margin is slight, however.  

OTOH, there is a root of some kind grown in Canada
that is more efficient .... time to invade Canada?  

Cheers,

Charlie

You are correct, sir! It does take a bit more energy to make ethanol/methanol than you get in energy output returned. Add to that that these fuels offer only about 78-82% of the 'bang' of gas, which usually translates to lower gas mileage in an unmodified engine, and you get less than bupkus.

No free lunch. Yet.

I vote we sell Canada to the highest available bidder. Probably cut off half the deficit in one swell foop.

 

[JohnP]

100 mpg - I don't think so, not even in the small ones! SUVs have driven down the fleet average mileage considerably. Auto manufacturers have worked the technologies hard to get the current mpg rates with the increases in vehicle weight and engine sizes. Leaving driving styles out of the equation, it would be a major advance to just double the mpg levels assuming similar size vehicles.

Improvements to mpg would require changes in technology, yes, but those would bring their own cost and reliability penalties. I find it hard to conceive of going to the gaseous fuels (hydrogen, propane, etc) since you need pretty large volumes to give one the desireable ranges between fillups. Those fleet propane trials (1980 vintage) worked fine for local travel but there were safety and practical range limitations.

I like the hybrid technology and am surprised that it has been relatively slow to catch on. I have driven a friend's Honda Insight (2 seat hybrid) and was pleased with the drivability; he gets disapointed when the mileage is below 60 mpg, but to do that Honda had to practically make everything on the car aluminum. The new Civic and Toyota based hybrids use more steel and as a result are not as fuel efficient (40-55 mpg). GM keeps claiming that they will make available a full sized hybrid truck that will get 20 mpg; I suspect it will have a slight advantage in torque due to beefy electric motors integrated in the system.

The main technologies that help hybrids are the battery systems. There are some pretty competitive battery systems that can store the needed watts in a small enough volume to use in these vehicles.

There are not miracles available now but there may be that '...light at the end of the tunnel'.

JohnP

 

[Marshac]

I saw a photo of a hybrid BMW X5 burning out its tires awhile back.... something like 700 ft-lb or torque. They were investigating the technology for performance, not efficiency.

I just googled for you-

http://www.autoexpress.co.uk/previews/38421/bmw_x5_hybrid.html

 

[Spanky]

If you live in suburbia 45 minutes from work, catching the bus might make the commute time two hours

I used to live only 4 miles from work, but it took almost 2 hours if I took the bus because of its routing system. The bus transit system provided routes between the suburban areas to downtown of its metropolitan city only. If you had to travel from one city to another city even though it might be only a couple of miles away, it would take a while. For example, I took the bus to downtown St. Paul, transferred to another bus to downtown Minneapolis, and transferred again to arrive at work (which is 4 miles away from my apartment). It was no fun at all especially in the winter when temperature fell into the single digits.

Spanky

 

[cute fuzzy bunny]

I used to take the train into Boston from the 'burbs. Was nice, I lived a few minutes walk from the train station and a few minutes downtown to my office. Cost was 1/4 what I'd have paid just to park.

Unfortunately I had to be up at 6am to catch a 6:50 train to get to work by a few minutes past 8, and I didnt get home until almost 7:30 after catching the 6:30 train out of town. I definitely caught up on my reading and it was a very peaceful, low stress period in my life. After about a year though I lost it and had to start driving in. I 'gained' over an hour of time back in my day, although the stress of driving in and out of "I'll kill you for changing lanes!" town was very high.

Tried the bike when I moved to the SF Bay Area in '92. I lived 2 miles away from work. Was great except for the days when it rained torrentially, which is December through March. The bike thing wouldnt have worked out too well for me back in Boston either.

I imagine we can already see the future. Little european-like skateboard cars that get 50-60mpg and are driven when you have to get some where, not for pleasure trips. Hell, I take my dogs for a ten minute ride around the neighborhood on days when we dont go anywhere else, just to get them their 'car fix'. If gas was $5 a gallon...I might just open the front door and tell them to come on back when they're done.

 

[Eagle43]

Since I had lived in Europe a little, and wanted to save money, I thought about biking to Mega-Corp. Had I done so, I would be pushing up daisies today. No bike lanes, and no respect from Texas drivers, and would have had to shower after arriving.

My one sure trip each day since retirement is to the gym. I'd ride my bike there, (only couple miles) except someone would steal it. If gas keeps climbing though, I might try to store it in the locker room while exercising. Or, since it's only a couple of miles, just walk there and back. Trim exercise routine accordingly.

We are not bike friendly here in USA, although I hear that Portland, Oregon is, and I hear they have a quality public transportion system. Anybody been on it?

 

[JohnP]

Marshac - Thanks for the link to the BMW hybrid article. The best mileage in any engine is obtained when the engine is allowed to run at a fixed optimum engine rpm. The idea of hybrids is to take a smaller conventional engine and run it within an efficient rpm range; then when extra power is needed you can kick in the electric motor for the typically short duration to pass or get out of the way of a truck. The electric motor in the small Hondas are 15-20 horsepower which can be delivered with a lot of torque especially at low rpms where conventional internal combustion motors cannot supply much torque. So there is an opportunity to combine two engines/motors to even, in the case of the BMW, enhance performance with enhanced mileage.

BMW must have a higher HP electric motor to get the wheels to smoke. It is really only a matter of sizing of the motor and the battery pack (and the capacitor pack in the case of the BMW). You can engineer virtually any level of hybrid power - the only real limit is the weight, cost, and power tradeoffs that are traditional. Actually, the hybrid motors and battery systems can be pretty light because of the technology available today.


JohnP

 

[Marshac]

I really think that battery technology is holding up the show somewhat too. It wasn't that long ago that your only hope for high Wh batteries was lead acid... not great for the environment (unless recycled properly), and very heavy. Lithium batteries have come a long way in the past decade, and I'll bet money that we will see injectible lithium polymer batteries in the near future (think car body panels that are actually batteries). A few years ago people were talking about ultracaps, but I haven't heard much lately.

If you couple the Li battery advances with some of the exciting photovoltaic research, you come up with some nifty possibilities.... imagine an electric car with solar panels embedded into the car that could soak up enough juice during the workday to get you back home.... obviously not for AK residents, but cool nonetheless.

 

[MJ]

After 9/11, I wanted to do my own liberal patriotic bid to limit my gas consumption that has made "our" oil friends super super rich, so I started riding my bicycle again in a big way, averaging about 5k a year. This included commuting to work in NYC traffic 20 miles RT which gives me a 90 minute daily aerobic workout and it only added an additional 15 minutes to my commute. Since I am single, I also do my shopping by bike as well. I really love riding my bike.

MJ

 

[JohnP]

Interesting dreams, Marshac! Let me add a couple of tidbits here.

Fifteen horsepower has always been a sort of personal benchmark for me; that is the power level that a vehicle uses on-average to get 15 miles per gallon (using fuel heating value, engine efficiencies, etc) - if you want to double your MPG, you simply half your horsepower requirements (change Aerodynamics, engine efficiency, etc). Not an easy task!

Electric motors as a primary power source for a vehicle are a real challenge; 15 hp or greater continuous-duty electric motors are pretty big and heavy. The battery system to support even only a couple hour range is big, as can be seen in the EV1.

On the other hand, 15 hp or greater intermittent duty (as in 5 or less minutes per hour duty) electric motors can be significantly smaller with correspondingly smaller battery systems. Add a small 15+ hp intermittant duty electric motor to an auto with a conventional internal combustion engine and you can get good improvements in mileage without losing acceleration properties.

That is what ConsumerReports discovered (Apr 2005 issue) in comparing acceleration on the new Accord hybrid compared to the conv Accord. You're not going to make a hybrid-based NASCAR 200 or Indy 500 car but you would get an in-town driveable vehicle.

JohnP

 

[indymom]

Not being an engineer, does this mean that the hybrids are a good idea? I hope so...it would be so great not to have to depend on oil for so much.

 

[Marshac]

Not being an engineer, does this mean that the hybrids are a good idea? I hope so...it would be so great not to have to depend on oil for so much.

Hybrids excel in stop-and-go city traffic. Anything to reduce oil consumption is a good thing IMO.

 

[JohnP]

Indymom - The short answer is - Hybrids Rock!

1. The technologies are available now.

2. Demo vehicles have been on the road for several years.

Best Regards

JohnP