Wanting info on Hydrogen engine conversion

[fivebob]

Mmm, 2 sides to every coin.

In this case they're both heads

No matter what way you toss it up you cannot break the first law of thermodynamics. There is absolutely no way to obtain more energy out of a system than you put in. Given losses are inherent in any system you will actually be less fuel efficient, or drain your battery.

[MAGN1T]

If you're petrol engine is only 10% efficient at road cruising speed , then if you were able to increase it's thermodynamic efficiency to say 12% by tuning it for lean burn and advancing the ignition, then you'd make large overall savings.

Steve

[fivebob]

How do you plan on doing that?

You need energy to create Hydrogen, that energy is created by the inefficient engine. Even if that allowed the engine to run leaner, by utilising the hydrogen generated as a replacement for the fuel ,you cannot get the same HP as you would without the hydrogen. So for the same HP level you will burn more fuel.

It's quite simple really, there is no free lunch.

[MAGN1T]

. So for the same HP level you will burn more fuel.

It's quite simple really, there is no free lunch.

Only if you're unable to increase the thermodynamic eficiency.

You're looking at it from a one eyed physics point of view when you should also be looking at it from a chemistry point of view.

Every litre of hydrogen oxygen mix will displace 1 litre of air which is nearly 80% nitrogen which does nothing but get in the way.

It's changing the chemistry of combustion.

[Adamal]

It's quite simple really, there is no free lunch.

That took me back to 5th form Physics. My teacher ALWAYS said that!
(In a Scottish accent) "Theres no such thing as a free lunch"

[fivebob]

Only if you're unable to increase the thermodynamic eficiency.

You're looking at it from a one eyed physics point of view when you should also be looking at it from a chemistry point of view.

I'm not looking at it from any view except the one that says it isn't practical either chemically or physically to get more power out than you consume producing the hydrogen.

Every litre of hydrogen oxygen mix will displace 1 litre of air which is nearly 80% nitrogen which does nothing but get in the way.

Not quite correct. That one litre displaces on litre of of combustion mixture, it will also generate less gas volume so contribute less to the combustion pressure.

It's changing the chemistry of combustion.

Still doesn't change the physics of combustion, and, unless you can change the way the fuel burns to get more energy from the petrol that is burnt, it doesn't change the chemistry either. Regardless of what way you look at it you still produce less energy that you use to generate the hydrogen in the first place.

[MAGN1T]

Maybe you should read up on lean burn technology.

[fivebob]

Maybe you should read up on lean burn technology.

Maybe you shouldn't assume that I haven't

[fivebob]

Ok here's a few numbers for you to consider.

It takes 3.55Kwh of energy at 100% efficiency to convert 1 litre of water into approx 1870 litres of Hydrogen & Oxygen mixture.

12v at 10 amps draw will produce approx 63l of this mixture per hour.

At 2000rpm a 2 litre engine with 100% volumetric efficiency will consume 120,000l of air fuel mixture per hour.

If you used the 2H2 + O2 mixture at the rate it was produced that would mean that it accounted for 0.05% of the combustion mixture.

So someone please explain to me how you get 10-20% improvement in fuel efficiency from a component that only makes up 0.05% of the combustion mixture.

Ok then lets draw a few more amps, problem is that water has a high resistance so you have to add something like salt to lower it's resistance. Even if you could up the current draw to 100amps that's still only 0.5% of the combustion mixture.

[MAGN1T]

Starting off with wrong assumptions always gives wrong answers.

When it comes to economy at part throttle, VE is veyy small, maybe less than 10%.

Steve

[sergei]

Starting off with wrong assumptions always gives wrong answers.

When it comes to economy at part throttle, VE is veyy small, maybe less than 10%.

Steve

Still it requires about ~10kW to cruise at 100kph (no gradient). say you spend 0.5kW on making brown gas that would be still only 5%.
That is at 100% efficiency.
Burning hydrogen/oxygen mix will only have ~20% efficiency (read about Carnot cycle). Making electricity from crack will have ~70-80% efficiency.
Basically you will only make 10-15% out of those 0.5kW spent on making the gas. let me put it in numbers: 10% out of 0.5kW is 0.05kW or 50W.
Your spot lights take more power than that. Your car stereo takes probably 4 times as that when it is cracking (assuming you don't have an amp and subs). Your heater fan takes 4 times, that is just the fan, no A/C.
And A/C... god knows how much it takes, I would assume at least couple of kilowatts...
You are far better turning all of that unnecessary equipment, it will make far larger impact (well it will have at least a positive impact unlike the negative result from HHO).

EDIT: I forgot to account for electrolysis inefficiency, so lower that number to 5% or 20W from 500W spent .
Note: humans can produce ~200W of mechanical energy at relatively sustained rate (after some practising) so you far better of installing flinstone propulsion system than using that HHO

[barryogen]

Note: humans can produce ~200W of mechanical energy at relatively sustained rate (after some practising) so you far better of installing flinstone propulsion system than using that HHO

sustained for a while maybe, but any more than 2 or so hours and you'd be shagged well and truly.

[sergei]

Note: humans can produce ~200W of mechanical energy at relatively sustained rate (after some practising) so you far better of installing flinstone propulsion system than using that HHO

sustained for a while maybe, but any more than 2 or so hours and you'd be shagged well and truly.

Sorry about russian humour.

[fivebob]

Starting off with wrong assumptions always gives wrong answers.

When it comes to economy at part throttle, VE is veyy small, maybe less than 10%.

True, but I left the conversion at 100% efficient too, I don't notice you complaining about that

VE doesn't changes as much as you imagine at light throttle openings it may get down to 30-50%. Lowest manifold pressure I've seen in the hundreds of hours of logs I have occurs when the throttle is completely shut and the engine is on overrun, even then the manifold pressure only goes down to about 20kPa at 2000rpm.

Typical manifold pressure I've seen is around 67kPa at 10% throttle, dropping to around 35kPa at 5% throttle. So 50% VE is probably more accurate. 50% VE and 50% conversion efficiency cancels each other out.

The premise remain true. However lets just for a moment assume your 10% VE is correct and conversion is 100% effective, that's still only 0.5% of the combustion mixture, how can that give you a 10-20% better economy???

Not really possible especially when you consider that light throttle, low rpm is where the engine is currently using the least fuel (my logs tell me that at 5% throttle injection duty cycle is around 2.5% rising to about 6.5% at 10% throttle openings). If you recalculate for the situation where there is more fuel to be saved, say 3000rpm and 80-110% VE it gets much worse for the water to hydrogen conversion case.

[Trls250s]

The thing is so rediculiously easy to build.

Why not try it and see rather then discuss theory.

Also cambell live neither disproved or concluded that this worked. The Thermodynamics professor on the show said that a fuel savings of 30 - 40% was rediculious, but he stated he saw no reason why you wouldnt get some fuel savings from the device, just not as high as everyone is claiming.

I got some questions for the theory guys, these are genuine out of interest.

If i ran a 100Watt amp and a big sub woofer would that decrease the HP of my car and put more load on the alternator?

Would a car with a full sound install (excluding the weight of the stuff) would consume more petrol then a car without a sound system as it draws more electricity?

Or does an alternator over generate power, ie creates more power then the battery can store, therefore wasting some of the mechanical energy converted from the heat engine process?

[pc]

The thing is so rediculiously easy to build.

Why not try it and see rather then discuss theory.

If I told you that a standard 1600cc corolla would do 350kph if you took enough of the interior out would you believe me?... I would hope that the answer is no.
This hydrogen electrolosis in the car using the car's power and making the car more economical is just as absurd. There is no need to discuss it because it is that absurd....
It is just as unachievable as a standard 1600cc corolla doing 350kph without being dropped from orbit.

Yes putting any load on a car electrical system will make the car less economical in Km/L. It might not ever be noticable because there are so many other factors that have a bigger bearing on fuel economy, but the effect will be there.

[Heylin]

A company in NZ OctaFuel installs Hydrogen Fuel Cells in cars for around $4000 and claims 20 - 40% savings.

Not sure if its the same as the glass jar or a more effiecient system but even at 20% it would take 2 - 3 years to pay back the cost, and your not gauranteed that the fuel cell will be as efficient (or even working) at the end of that period of time.

Im sure as catalyst and plate technolgy gets better cells will last longer, require less servicing and produce more hydrogen for a given current draw.

[sergei]

If i ran a 100Watt amp and a big sub woofer would that decrease the HP of my car and put more load on the alternator?

yeah it decrease the power by little bit more than 100W (if that is running at full blast)

Would a car with a full sound install (excluding the weight of the stuff) would consume more petrol then a car without a sound system as it draws more electricity?

yeah

Or does an alternator over generate power, ie creates more power then the battery can store, therefore wasting some of the mechanical energy converted from the heat engine process?

Alternator only loads as much as it takes (obviously there is some loss of 10-20%).

But in this example the weight of the sounds will affect a lot more than current drawn by alternator.
If the car makes 100kW, 1kW is not much, while 100kg extra in 1000kg is a lot more.

[sergei]

A company in NZ OctaFuel installs Hydrogen Fuel Cells in cars for around $4000 and claims 20 - 40% savings.

Not sure if its the same as the glass jar or a more effiecient system but even at 20% it would take 2 - 3 years to pay back the cost, and your not gauranteed that the fuel cell will be as efficient (or even working) at the end of that period of time.

Im sure as catalyst and plate technolgy gets better cells will last longer, require less servicing and produce more hydrogen for a given current draw.

Catalyst???
http://en.wikipedia.org/wiki/Catalyst

As far as I know decomposition of water is endothermic reaction, catalyst as by definition is something that lowers threshold energy required to trigger exothermic reaction.

[sergei]

as for real fuel cells, they take hydrogen(fuel) and oxygen(oxidiser) and convert to electricity and by-products (heat and water in hydrogen case).