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Unread 01-23-2014, 11:40 PM   #31
SchizophrenicMC
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Let's do some math! (We'll assume a perfect world with no loss to friction and for the most part, perfect conversions)


4 liters of engine at 2,000rpm (a reasonable freeway speed engine RPM) displaces 3200 liters of air per minute, give or take. (4000cc * .8 (Volumetric Efficiency) * 2000rpm = 3,200,000cc = 3200l) Given that, we can discover the following:

In order to maintain stoichiometry the engine must consume 200l of gasoline vapor every minute (3200/16 (~15 parts air + 1 part fuel = stoich) = 200) which is equivalent to 1.25l of liquid gasoline at sea level at something like 60 degrees fahrenheit or something.

The stoichiometric ratio of air to hydrogen by volume is 2.4:1, meaning for every cubic centimeter of hydrogen you introduce, you must also have 2.4cc of air. The engine can only aspirate 3,200,000cc of air/fuel per minute at 2000rpm. That's 3,000,000cc of air and 200,000cc of gasoline. To produce an efficient burn of the hydrogen, you'd need to start substituting. If you manage to add 50,000cc of hydrogen gas per minute (let's just throw a number out there) you'll need to dedicate 120,000cc of air to it. That reduces the amount of gasoline vapor you can use and maintain stoichiometry, to 180,0000cc.

So you've used less gasoline at that RPM, assuming everything is perfect and the gas generator doesn't use any energy. However, hydrogen's energy density by volume is far inferior to gasoline's. Liquid hydrogen contains 140MJ of energy per kilogram, but only 10MJ per liter. Gasoline contains about 35MJ per liter. Therefore, for every unit of gasoline you replace with hydrogen, you lose 2/3 of the available power from that unit. When you lose power, you inherently lose economy.

To tie that into our example, when you remove 20,000cc of gasoline and replace it with 50,000cc of hydrogen, assuming both are ideal gases (they're not and hydrogen is even more diffuse than gasoline in real life) you still end up losing nearly 30% of the power the gasoline you reduced could have given you, and so you have to now increase RPM, air intake, and fuel consumption in order to make up for it.

Even if you could generate hydrogen with no input energy from your engine, you would still end up worse overall.

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Unread 01-24-2014, 12:46 AM   #32
fastfreddie
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Quote:
Originally Posted by SchizophrenicMC View Post

In order to maintain stoichiometry the engine must consume 200l of gasoline vapor every minute (3200/16 (~15 parts air + 1 part fuel = stoich) = 200) which is equivalent to 1.25l of liquid gasoline at sea level at something like 60 degrees fahrenheit or something.
Typo? That's like 3.2 MPG.
I think maybe you forgot a step in your stoich equation.
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Unread 01-24-2014, 11:36 AM   #33
SchizophrenicMC
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Originally Posted by fastfreddie View Post
Typo? That's like 3.2 MPG.
I think maybe you forgot a step in your stoich equation.
I can't remember if I forgot something, but it's either I missed a huge part of the equation, or that the equation I used assumes something unrealistically. Probably the second one. That was all done at 12:30 at night after a long day of driving and buying CDs for a ZJ whose CD player, as it happens, does not work.

I think maybe the equation assumes WOT operation at 2000rpm, which would lead to peak fuel consumption and power in the assumption? And I can't remember whether that even matters, anymore. The point remains, however: it's physically impossible to generate hydrogen onboard and gain fuel economy.
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Unread 01-26-2014, 02:24 PM   #34
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Not to worry, it can be quite exasperating even at your peak daylight hour.
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Unread 01-28-2014, 09:16 PM   #35
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Quote:
Originally Posted by SchizophrenicMC View Post
I can't remember if I forgot something, but it's either I missed a huge part of the equation, or that the equation I used assumes something unrealistically. Probably the second one. That was all done at 12:30 at night after a long day of driving and buying CDs for a ZJ whose CD player, as it happens, does not work.

I think maybe the equation assumes WOT operation at 2000rpm, which would lead to peak fuel consumption and power in the assumption? And I can't remember whether that even matters, anymore. The point remains, however: it's physically impossible to generate hydrogen onboard and gain fuel economy.

As i said. There are numerous $million + rewards out there for the first person to prove physics wrong. Browns gas, the original scam, was in 1978. In almost 4 decades not a single system has claimed a penny. Most 'gains' people report happen even when the system is off (which is real funny) and only after you install all the hardware to make the computer run lean almost and sometimes past the melt down stage.

Every single time you convert matter from 1 form to another, you lose energy. Its blatantly impossible to recombine into the original state without losing twice.
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Unread 01-28-2014, 09:57 PM   #36
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As i said. There are numerous $million + rewards out there for the first person to prove physics wrong. Browns gas, the original scam, was in 1978. In almost 4 decades not a single system has claimed a penny. Most 'gains' people report happen even when the system is off (which is real funny) and only after you install all the hardware to make the computer run lean almost and sometimes past the melt down stage.

Every single time you convert matter from 1 form to another, you lose energy. Its blatantly impossible to recombine into the original state without losing twice.
Thermodynamic Entropy, ladies and gentlemen. The one irrefutable truth of the universe. That hasn't stopped people from trying to refute it.
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Unread 01-29-2014, 12:47 AM   #37
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Unread 01-30-2014, 04:08 PM   #38
skippy102595
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What's the best way to get the most out of a 1993 YJ? I'm young and I really can't afford to buy gas 3 times a week for it, but I love it so much that reluctantly, I do. 1 Tank gets me from home to school all week without refueling but once I factor in going to work I find myself refueling it around Thursdayish, plus taking out friends and girls doesn't t help much either. It's a 93 YJ 2.5 liter manual. Any tips are good if anyone has any.
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Unread 01-30-2014, 04:54 PM   #39
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Originally Posted by skippy102595 View Post
What's the best way to get the most out of a 1993 YJ? I'm young and I really can't afford to buy gas 3 times a week for it, but I love it so much that reluctantly, I do. 1 Tank gets me from home to school all week without refueling but once I factor in going to work I find myself refueling it around Thursdayish, plus taking out friends and girls doesn't t help much either. It's a 93 YJ 2.5 liter manual. Any tips are good if anyone has any.
Buy a prius(or any other tinbox on wheels) and sell/park the YJ.That is the only way.
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Unread 01-30-2014, 08:04 PM   #40
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Quote:
Originally Posted by skippy102595 View Post
What's the best way to get the most out of a 1993 YJ? I'm young and I really can't afford to buy gas 3 times a week for it, but I love it so much that reluctantly, I do. 1 Tank gets me from home to school all week without refueling but once I factor in going to work I find myself refueling it around Thursdayish, plus taking out friends and girls doesn't t help much either. It's a 93 YJ 2.5 liter manual. Any tips are good if anyone has any.
Buy a motorcycle and gear. Figure around $3,000. Enjoy 65+mpg which will add up to savings much more quickly than any car will.
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Unread 01-30-2014, 09:41 PM   #41
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Haha, you people are funny. Who in the right mind would trade for a Prius? There's no fun in that at all. Seriously though any REAL tips or advice?
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Unread 01-30-2014, 11:39 PM   #42
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Haha, you people are funny. Who in the right mind would trade for a Prius? There's no fun in that at all. Seriously though any REAL tips or advice?
See my tip, and then shut up. You'll never exceed 15mpg in a YJ. By the time you've sufficiently re-engineered the thing to do so, you'll have made it unusable offroad, and spent thousands of dollars making it into something completely different from the vehicle you like.
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Unread 01-31-2014, 11:33 PM   #43
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Hmm, very interesting. All I can add is if you have changed your tire size a re-gear can definitely help you get back to original MPG. However, the breakeven point after spending over $1000 for the new gears installed might not happen if you are not keeping the said Jeep that long.

Defrinitely no light bars above the roof line
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Unread 02-01-2014, 06:23 PM   #44
longtro
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Learm to drive super tame.. basically barely keeping up with traffic.. small (stock) tires.
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Unread 02-09-2014, 08:57 PM   #45
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Remove your spare tire reducing weight will help also a full tuneup new spark plugs, new air filter ect can help gain a few mpg
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