Basic explanaition of Internal combustion Engines, to the detriment of the high-mileage carbuerator

The university of Wisconsin ^ | 10-12-02 | Paul U

[pbu4him]

I am posting this to inform everyone about how cars work, so they don't buy into scams about some product that claims to increase the gas mileage of a car.

From the University of Wisconsin: Scientists have calculated the average amount of potential energy stored in various types of fuels used by humans as an energy source. Conversion factors:

1 gallon of fuel oil = 145,000 BTU 1 cubic foot of natural gas = 1,031 BTU 1 kilowatt hour of electricity = 3,412 BTU 1 cord of wood = 20,000,000 BTU 1 gallon gasoline = 125,000 BTU End quote

As you can see, 1 gallon of gas has 125,000 British thermal units of energy available in it. This is equal to 36.63 Kw-hours, 131881 KJ, 97271157 ft-lb, or 31499470 calories.

Now that you know how much engery is at your disposal, you just have to figure out what you need to use it for. We are trying to find out miles per gallon in the end. So, for instance, it you wanted to do work, you need to find out how much energy it takes to do that work. Then you can see directly from the conversions above how many gallons of gas it took to do the work.

Lets begin. The work we want to do is moving a car. Lets assume the car is already moving, that gets rid of the inertia losses. Theoretically, once your car gets moving, it should never stop, That would mean you get a gazillion miles per gallon. But there are losses due to friction, and heat going out of your system (the car). So, we have to find out: 1. How much work could be done by the engine. 2. How much work is done by the engine.

From another academic site, I found the following information for #2: "A piece of buttered toast contains about 315 kilojoules of energy. With that energy you could:

Jog for 6 minutes Bicycle for 10 minutes Walk briskly for 15 minutes Sleep for 1-1/2 hours Run a car for 7 seconds at 80 kilometers per hour (about 50 miles per hour) " 7 seconds is .0019444444 hours. That means for 315 KJ you run the car for 7 seconds. so that is how much work we need to do just to keep the car moving on a flat road at 50 MPH. Therefore you can get 3240 KJ / mile.

Using our 131881 KJ per gallon of gas, that means we get 40 Miles per gallon! This is the best MPG rating you can get out of this car, because you used all the energy in the gas and put it right into doing your work. Your work included rolling resistance, air resistance, grating electrical power for auxilliary devices, etc.

for #1: Now lets take a look at our car. The work you need to do is various: accelerate, the car, overcome rolling resistance, etc. but you need 213514 Newtons of force to be pushing on your car to get it up to speed. WE know KE = 1/2 mass*Velocity squared. We will account for that, the energy it takes to move the car that fast. assuming the car is 4000 lbs, you are using 5280000000ft^2-lb/s^2 to move it. Thats 5.428 ft/s^2 per gallon of gas you could theoretically get out. You need 48000 ft*lb/s^2 each time you go from stop to start. Do the math, and you will come out with your car being about 1/4 as efficient as it could be.

[pbu4him]

Scientists have calculated the average amount of potential energy stored in various types of fuels used by humans as an energy source. Conversion factors:

1 gallon of fuel oil = 145,000 BTU 1 cubic foot of natural gas = 1,031 BTU 1 kilowatt hour of electricity = 3,412 BTU 1 cord of wood = 20,000,000 BTU 1 gallon gasoline = 125,000 BTU

[mvpel]

There's something amiss here, because my Acura 3.2 TL gets about 25-28MPG, not 10MPG.

[RobRoy]

Well both of my Rolls' get less than ten mpg, and my Dino Farrari gets 12. But BOTH my Hummers get 14. Go figure.

I don't bother checking the mileage for my Cesna Citation. My pilot does all that for me. I know it takes more gas than any of my cars, though.

But it goes faster than even the Ferrari.

[RobRoy]

Just kidding.

My bicycle is least efficient but most fun - if I've carbo loaded correctly anyway.

[zeromus]

I am posting this to inform everyone about how cars work, so they don't buy into scams about some product that claims to increase the gas mileage of a car

Do the math, and you will come out with your car being about 1/4 as efficient as it could be.

So my car is not as efficient as it could be; therefore i should ignore any advertising that claims to increase its efficiency?

[prisoner6]

Hmmm...and theoretically bees can't fly.

Actually I'm pretty familier with allt he conversion factors you listed. Cord wood varies greatly of course, and most other fuels do for a variety of reasons as well - contamination, etcetera.

IC engines keep getting more efficient, and other factors - like weight, areodynaics and others, have generally been improving too. So cars ARE getting better gas milage than they did years ago.

But remember the old Mobil Economy Runs? Fairly BIG cars were getting 80+mpg.

And the absolute best economy I ever saw in one of my cars was in a Renault R5 Le Car. It consistantly had 54 highway 48 city. That was with old technology and back in the late 70's -early 80's.

Of course being a French Automobile it made a better lawn ornament than passenger car, but I was comfotable enought with it to take my family on several LONG trips ov a couple thousand miles each time.

Heck even back in the 60's I had a Renault R16 that gave 26-32 mpg. And in the early 70's I drove a rotary engine RX2 ( that's NOT a misprint!) that was as fast as my 67 289 Mustang and still returned 20-28 mpg while the Mustang struggled to top 14mpg.

Sure there's a top limit eventually, but I think there's lots of room to improve. BUT being a conservative I DON'T believe MANDATING mpg standards.

prisoner6

[JoeSixPack1]

The amount of ERG's one expends reading this useless stuff can be bottled and sold at the rate of 1/24th the daily allotment if calculated on a 24 hour basis. But if a water injector system is attached at the hairline and the solar rays have diminished intensity the 60@1/24=1 erg hour can be expotentialy expanded to compensate for inefficient heat dispersion through persperation and hydro-electric energy retention is multiplyed by a factor of 3.

This works well if you force your wife to mow the lawn on Sunday. However, nourishment for Sunday afternoon is also reduced by a factor of 2.

But expending further erg's by physically dialing Guido's Pizza can reduce fuel reliance of any vehicle in your driveway.

[Sgt_Schultze]

Maybe these "scientists" could help a little by telling us how much energy can be found in a sunbeam. Then they could stop the weenies from calling for tons of cash to be spent chasing rainbows and solar energy and help us find more oil and gas.

[ATOMIC_PUNK]

[A Vast RightWing Conspirator]

I believe that scientists also demonstrated that a bumblebee can't possibly fly.

[cinFLA]

Any gun experts out there?

What has buttered toast have to do with automobiles? Oh, yeah. They both have "carbs".

[Ken522]

Nice picture - that's an aircraft engine, isn't it?

[Consort]

Here's the total energy used since the creation of the universe:

[Hunble]

Cool, will YOU certify this with the FAA so that I can use it on my airplane?

Why do I have a feeling that if I install this on my airplane, the need to find emergency landing locations will be required?

[Hunble]

This works well if you force your wife to mow the lawn on Sunday. However, nourishment for Sunday afternoon is also reduced by a factor of 2.

I plead guilty your Honor!

Actually, after my wife's auto accident that left her crippled 2 years ago, mowing the lawn is her best rehabilitation method.

Unfortunatly, I have to look at my neighbors as they watch my crippled wife mowing the lawn.

[cinFLA]

To increase efficiency, use the hybrid gas-battery system. Install wind vane generators on the roof to capture the wasted wind energy and feed that back into the batterys.

[lavaroise]

Well both of my Rolls' get less than ten mpg, and my Dino Farrari gets 12. But BOTH my Hummers get 14. Go figure.

I don't bother checking the mileage for my Cesna Citation. My pilot does all that for me. I know it takes more gas than any of my cars, though.

But it goes faster than even the Ferrari.

I'm no business genius, but I'll invest in your money before I'll invest in the fake paper money and politics of bicycle riding advocates (most of whom never ride their bicycles to work anyway) :-)

[Criminal Number 18F]

Your Acura is an efficient car which is probably lighter than the example. Unfortunately this post fails at the intended goal, probably because the original author spends all his time around fellow math/physics/engineering types and isn't aware of just how little science and math the average American knows -- or wants to.

Popular culture is bitterly antiscientific, to the point that scientists are only portrayed in popular entertainments if they can be shown as mad or at least extremely weird. Not surprizing that kids, most of whom are raised by TV, don't pursue challenging and rewarding work in science or engineering, and leave the field to the immigrants (if you don't believe me, attend a university commencement).

The author's point is that a gallon of motor gasoline (one of the most efficient fuels available, in terms of energy contained by weight and by volume) only contains X amount of energy. That's why the differences between different cars' fuel consumption are matters of degree instead of matters of orders of magnitude.

My Corvette with many performance modifications gets about 21 miles per gallon in mostly fast highway driving. It probably weighs more than your Acura, so it's certainly less efficient. Still, they are close when you consider that one is a practical all-round car, and the other throws practicality to the winds but still gets 70-odd percent of the mileage.

The best mileage right now is provided by the Toyota and Honda hybrids, which don't even double the mileage of your Acura and which make some pretty major sacrifices. Like being able to get out of the way of a speeding tractor-trailer, or keep the humans inside alive if one hits you.

The most efficient vehicles are motorcycles. Because of their light weight THEY can be orders of magnitude more efficient than cars. But they are a dead-loss as far as practicality goes. TANSTAAFL.

And there's no such thing as a 150-mpg carburettor either.

d.o.l.

Criminal Number 18F

[JoeSixPack1]

Unfortunatly, I have to look at my neighbors as they watch my crippled wife mowing the lawn.

Hey, no problem. Make her mow it at night!

(Flame suit in place, fire away)------:-)

[Hunble]

Hey, no problem. Make her mow it at night!

Even my wife laughed at your reply!

ROTFLMAO