There is no point in using solar energy to electrolyze water so that you can burn hydrogen. You are much better off using the energy directly from the solar panels or charging a battery then using the energy from the battery. Electrolysis of water is a horribly inefficient process, and hydrogen is a bitch to store in quantities that are useful.
My point is, let’s say I want to increase the mileage on my 94 Geo Prism without dumping a lot of money into it, so converting it to full electric or conventional hybrid would be cost prohibitive.
As it sits right now I get about 22 - 30. It’s a 20 mile commute from here to work so I use slightly less than a gallon each way, let’s say 2 gallons per day. At $4.00 per gallon I spend $8.00 per day or about $40 per week on gas. Add another $10 for traffic and weekend driving and I spend $2600 per year on gas. I like for things to be paid for in about a year so any modification would have to pay for itself in that time.
Let’s say I spend $100 on a modification. That modification would have to increase my MPG 3.8% to pay for itself. This takes my mileage to 22.8 - 31.4 MPG.
Harbor Freight has a 25 watt / 12 volt solar cell for $159. The conversion systems I have seen are around $50 for the plans and $60 for the parts. This makes the whole modification $269. At this price I would need a 10.3% improvement taking my mileage to 24.27 - 33.09 MPG. This would (should) lower my gas bill by $269 per year.
Although I can see where keeping my tires inflated and my engine properly tuned and serviced I might be able to get this kind of improvement anyway, it does not look too unrealistic to me. I understand the futility of using solar power to create burnable HHO for storage and exclusive use, but would using solar to create HHO on demand for an existing IC engine make a difference in overall mileage?
Would 25 watts at 12 volts be enough to produce HHO in the first place?
The “claim” that most of these sites make is around a 40% improvement. This would take my mileage to 30.8 - 42 MPG. If realistic then it would drop my overall gas bill by $1040 per year, paying for the modification 3 times and lowering my yearly gas budget to $1560 per year. I would be spending the same on gas at $4.00 per gallon as I did when it was $2.40 per gallon.
Again, I’m not suggesting to run the car on HHO exclusively, the modification would really only peak out during daylight driving and then during the brightest of days. I’m just wondering if it could help a little, at least enough to pay for itself in a year and show some returns for years to come.
FTR, I bought this 94 Geo in 97. If I swapped out cars every three or four years I could see inconvenience in swapping out the modification or repurchasing it, but I tend to drive my cars for the long run.
Gasoline contains somewhere around 125 megajoules of energy per gallon.
Your solar cell puts out 25 watts; that’s 25 Joules/sec.
Cecil says you can “turn water into hydrogen and oxygen at about 70 percent efficiency, tops.” That means you can make approximately an amount of hydrogen containing 17 Joules every second.
To make hydrogen containing 125MJ, you would need to run this thing over 7 million seconds. That’s 2040 hours, or 85 days.
You’re not proposing any storage device on your vehicle. That means you can only use it while your engine is actually running.
You’re probably in your car about an hour per day. Even if we assume it’s sunny every day, you’re only using this device about 350 days per year.
So, charitably, you can replace around 1/5 of a gallon of gas with hydrogen every year. At today’s prices, that’s 80 cents.
(Note that large amounts of hydrogen injection will change the combustion dynamics, probably requiring an engine recalibration. The resulting system may very well have a higher efficiency than a gasoline-only system. However, we’re talking such small amounts here I think we can safely ignore this effect.)
Referencing Cecil’s column, Gas is 20% - 25% efficient . Therefore, given your information that gasoline has 125 Kilojoules, a gallon of gas would deliver, say, 25 - 31 Kilojoules. At 60 mph highway, given 30 mpg highway mileage, that comes out to 2 gallons per hour (which is a reasonable assumption for my car). So the car is using 50 Kilojoules per hour, or 13.8 joules per second.
As you said, the 25 watt solar cell produces 25 joules per second.
In order to produce enough potential energy to operate the vehicle at 60 mph wouldn’t the HHO generator need to operate at 55.2%? At 55.2% I would think the HHO would be enough to meet all of the power needs for that time. If I ran this system for ½ hour every day I would think it would reduce 1 gallon of gas per day – 350 gallons per year - $1400 per year. That would be switching from gas to HHO, and then back again.
I don’t think I could save $1400 per year using this kind of a system. For one thing I could only switch it on and adjust it while operating so that the HHO is consumed as produced due to a lack of storage (I reckon HHO doesn’t store very well either, under enough pressure it would most likely convert back into water and release enough energy to blow up the storage tank). For another there is city driving where switching back and forth would make it not worth the trouble. But it seems to me, just looking at it this way I should be able to do better than $0.80 per year.
Now that I think about it, 13.8 watts seems awfully low for an automobile to run on. Again I’m either misunderstanding something or severely underestimating something. If an engine (1.8 liter 4 cylinder) powers the vehicle on 13 watts, why would I not be able to just run it on a 25 watt solar cell (other than the expense of replacing the IC engine with and electric motor and appropriate controllers)?
I see a possible source of confusion here… 
Well then, i’m only off by a factor of 1000.
So a car uses 13,888 joules per second (roughly, see above post substituting mega for kilo). At 25 watts it would take 556 of these solar cells to produce the required energy. 13,888 watts at 12 volts would be 1,157 amps of current. Now it seems excessive.
Am I still off a bit here?
Your intuition is correct, as is Noone Special. 13.8 KILOwatts is a reasonable road power requirement, and you seem to be off by a factor of 1000.
[edit: you snuck in your last post while I was composing, but I’ll let this stand.)
Setting aside the three-orders-of-magnitude thing, hydrogen would be converted into mecahnical power in your engine at roughly the same efficiency as gasoline is: 20-25%, according to Cecil.
So with my measley little 25 watt solar panel producing HHO at, say, 50% effeciency, with the rest lost to heat and such and the HHO itself combusting at 25% effeciency (heat loss, friction, etc.) then I would be adding a free 2.5 joules per second to my 13 kilojoule per second engine. An improvement of 0.0181%. This results in a net savings of…
Drumroll please…
$0.41 cents per year of my $2600 fuel bill.
Heck, if I just wire the solar panel directly to the electric system and take a little load off of the alternator I would save double that. At $0.82 per year it would still take me 193 years to just pay for the solar panel. The Geo is an incredible automobile but even I don’t have much hope of it chugging along for another two centuries.
Ignorance fought, I think I understand the futility now.
It can be useful for these comparisons to remember that a horsepower is about 700 watts. So 13,800 watts is around 20 HP. Since folks are a lot more familiar with horsepower than watts, especially in connection with automobile engines, this is a much easier number to grasp.
I read somewhere that solar panels are going to power the air conditioner in next year’s Prius.
I heard that too, but it sounds more like a gimmick than anything else. Here’s why:
I have solar panels on my house. The government/electric company paid about 2/3 the cost of the system. Even with the subsidy, the break-even time is said to be 8-10 years. Multiply that time by 3 to get the actual break-even (let’s be charitable and call it 24 years, but of course that will vary based on the part of the country - someone in Miami will break even a lot sooner than someone in Seattle). But there are other variables which make the calculation even more difficult.
First, how does the cost of generating electricity with a hybrid’s generator compare with the cost of generating electricity with natural gas (which is what they use in my area)? With gasoline prices as high as they are, let’s assume it’s triple. OK, so that brings the break-even point down to 8 years again. But then there are some more issues. The solar cells on my house generate electricity whenever the sun is out. Any excess is sold back to the power company, so there’s no waste. The Prius has minimal battery capacity (remember, it’s not a plug-in hybrid) so even if the solar cells charged the batteries when the car wasn’t in use, once the batteries were fully charged, the rest of that power goes nowhere (although I suppose it could run the A/C just to keep the car cool when it’s sitting in the driveway, but that’s of minimal usefulness). So unless you drive this car all the time when the sun is shining, I don’t see how the solar cells will ever pay for themselves (I believe most cars are designed to last about 10 years).
If the A/C unit is small enough and the solar panel big enough it could be an independant system: solar cell - extra battery - A/C unit. Not having to draw on the engine for A/C compression and fan motors would probably improve mileage.
I’ve thought about this and, while I love my A/C, at night I generally prefer 2-60 air conditioning.
Roll two windows down and drive 60 miles per hour.
Heh. Come try that here in the summer. Ever pointed a blow dryer on high at your face? And yes, it feels like that even at night.
Yes, I’m sure it could improve mileage to some extent. My point was that the amount of energy produced by the photovoltaic cell over the lifetime of the car is not enough to offset the additional costs of having said cell on the car in the first place.
forgive me for not reading everyone’s response this may be a duplication of effort…
HHO systems do not improve engine performance they improve fuel efficiency by simply supplementing the fuel with a viable* replacement.
a vehicle travels 30 MPH at 30 MPG can go 30 miles in 1 hour using 1 gallon of gas.
hydrogen can power a gas engine at some unknown efficiency. 1 gallon of hydrogen would get you X MPG.
If you introduce a system that diverts amps to create Hydrogen from water and add that to your fuel line you can gain X MPG by not using that much gas.
*Mythbusters did prove that a gas engine with a carburetor could run on pure hydrogen. I assume it could do the same with fuel injection.
No, because then you have to burn more gas to make the hydrogen in the first place. Diverting amps means that the alternator has to put out more amps in the first place, which means that it’s harder for the engine to turn it, which means the engine needs to burn more fuel.
Or, in other words, TANSTAAFL (There ain’t no such thing as a free lunch)…
It’s just a con that been around a LONG time I remember this type of thing in the mid 70s right now I spent a lot of time trying to convince people the HHO or hydrogen boost doesn’t work (on another board).
But when you use THEIR numbers to check it out it still doesn’t work, even if you assume that it works.
They claim 50% to 400% increase in fuel mile. I’ll take a not so clean 1975 car that gets 30 MPG.
In 1975 the un-burnt hydrocarbons emission was 1.5 grams per mile so to make one gallon of gasoline you would have to drive about 2,500 miles. If HHO or Hydrogen boost was able to burn the un-burnt fuel your mileage would go from 30 MPG to 30.36 or an increase of 1.2%.
Now they recommend that you replace the oxygen sensor or put on a device to lean out the engine. If they lean out the engine to 17:1 (anymore than that and you’ll start having lean misfires) that would give you an additional 15%. This will also increase the cylinder temperature and will burn out valves, pistons, and heads, as well as increase the NOx and break a few federal laws in the process.
That gives us a total of 16.2% increase. We have to make up 33.8% to 383.8% of our fuel mileage increase through increase engine efficiency. The maximum theoretical efficiency of an internal combustion engine is right at 37%, with the average engine having an efficiency rating of about 20%. So if our engine was 33.8% more efficient our 20% would increase to 26.76% and there would have to be an increase in HP by the same percentage. So for every 100 HP starting you would increase HP by 33.8 HP. If it was 383.8% more efficient our 20% would increase to 96.76%. This would also mean an increase in HP by the same percentage so a 100 HP engine would increase by 383.8 HP. That increase is more the large enough to be measured by ANY shop with a dyno.
So the only real saving you receive is to lean out the engine to the point where you will have engine damage. And when you really look at THEIR numbers you see it’s not possible to make THEIR claims.
Several of the sites selling these Brown’s gas systems now recomend buying (and are selling) a device to lean out your automobiles ECU fuel injection system. They say it allows the hydrogen to be properly combusted, but leaning out the fuel injection system is more likely to be the source of any slight improvement in fuel economy. Of course leaning out the fuel injection system without a browns gas generator would also offer an improvement in fuel mileage.
cheers
don
**postpic200 ** said:
Can a 1975 car even get 30 mpg?