hydrogen fuel

Just a little bit I remember from the chemistry class in my high school days.
In the fuel burning process, one of the waste products is water vapour.
In the chemistry class, we did the calculalions of the formula of the chemical reaction of the burn process using octane as a fuel.
We were surprised to discover more water in volume was produced than fuel in volume used at standard temperature and pressure (which was 20 degrees celcius at one atmosphere I think).

Praxis, let us know when you have installed the kit.

Quote: "FWIW. My 109 with 2.25P averaged 17 L/100 (fitting an overdrive made no significant difference to fuel consumption IME). 20% less than that is 13.6 L/100, which I could easily achieve by having a light right foot."

Now you do surprise me... High on my wish list is an overdrive.......is there really no reason to install one of those either?

Is 13 L/100 really achievable with a 2 1/4 L?
Dave

Quote:

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Originally Posted by Mick_Marsh

Praxis, let us know when you have installed the kit.

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I certainly shall, Mick....although it is not a kit as such - NDM install the whole lot and retune the engine to suit the lean burn, etc. Also, at the price, it may take a while!
Dave:(

Quote:

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Originally Posted by praxis

Quote: "FWIW. My 109 with 2.25P averaged 17 L/100 (fitting an overdrive made no significant difference to fuel consumption IME). 20% less than that is 13.6 L/100, which I could easily achieve by having a light right foot."

Now you do surprise me... High on my wish list is an overdrive.......is there really no reason to install one of those either?

Is 13 L/100 really achievable with a 2 1/4 L?
Dave

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As bee-utey said - 0-5% improvement is probably the right ballpark for an overdrive. This is probably usually offset by you sitting on a higher speed with the OD engaged.

13 L/100 is possible - (almost) unladen, driving like a granny at ~85km/h with a well tuned engine and good tyre pressure.

Quote:

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Originally Posted by praxis

I certainly shall, Mick....although it is not a kit as such - NDM install the whole lot and retune the engine to suit the lean burn, etc. Also, at the price, it may take a while!
Dave:(

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That sounds slightly worrying... Leaning the engine out will cut most emissions (except NOx), but will increase EGTs. The levels of H2 these systems add is less than a 1% of the fuel being used.

It would be interesting to see what he does if he fits one of these systems to an EFI diesel or petrol, which cannot be "tuned" by most mechanics.

There is a Mechanical Engineer (with a degree), whose hobby is to debunk fuel saving gadgets. A link to the hydrogen generators section of this site is below.

Fuel saving gadgets - a professional engineer's view

Some interesting links on this page are below (watch the video) and explore the other links.

Real HHO information

And if you want to punish your brain there is this

Real HHO information

Now the hydrogen cell HAS received a lot of attention from various parties, BUT nobody has been able to SCIENTIFICALLY demonstrate that it works!

I guess the need for a free lunch is so strong that it defies all logic.

Why is it that all these alternative fuel ideas seem to be fitted to big yank tanks? Why not fit one to a little car and run it for next to nothing. That would be a better market to aim for.....If it worked!

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Originally Posted by stealth

Why is it that all these alternative fuel ideas seem to be fitted to big yank tanks? Why not fit one to a little car and run it for next to nothing. That would be a better market to aim for.....If it worked!

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Let's just imagine that one of them actually worked and produced a 10% reduction in fuel consumption.

On a big Yank tank using 20 litres/100km, that would save around 20 litres of fuel on a trip from Brisbane to Sydney.

On an economical car using 5 litres/100km, it would save around 5 litres on the same trip.

It takes a lot longer to pay for itself (if it works) in a economical vehicle. It pays for itself a lot quicker in a gas guzzler.

A question for the experts; am I correct in thinking that an internal combustion engine will be most efficient when exhaust gas temperature is lower, ie fuel energy has been used to move the pistons not just create hot exhaust? In this manner of thinking I wonder if water injection (if it does help at all) would work by taking combustion heat energy and turning the injected water into steam that in turn increases the pressure on the top of the piston and you get movement and a cooler exhaust? Feel free to point out any deficiencies in this logic as it is something I have wondered about for some time.

Quote:

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Originally Posted by John W

A question for the experts; am I correct in thinking that an internal combustion engine will be most efficient when exhaust gas temperature is lower, ie fuel energy has been used to move the pistons not just create hot exhaust? In this manner of thinking I wonder if water injection (if it does help at all) would work by taking combustion heat energy and turning the injected water into steam that in turn increases the pressure on the top of the piston and you get movement and a cooler exhaust? Feel free to point out any deficiencies in this logic as it is something I have wondered about for some time.

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It depends if you are talking petrol or diesel... Since petrol engines are the ones which can readily combust hydrogen:

Optimum efficiency actually occurs leaner than stoichiometric. This actually means the EGTs will be higher. However, if you lean an engine out too much the EGTs can be harmful/damaging, plus you will get very high NOx levels (but low CO and unburnt HC levels).

Water/steam injection can potentially reduce EGTs, therefore minimising NOX and also preserving the engine. Hopwever there are other flame speed/detonation issues to consider.

The holden Ecotec V6 engines (if you remember those?) were set up to burn leaner than the previous V6, thereby saving fuel.

Quote:

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Originally Posted by John W

A question for the experts; am I correct in thinking that an internal combustion engine will be most efficient when exhaust gas temperature is lower, ....

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Not exactly. The answer is yes, provided nothing else is changed, but of course, to get the lower exhaust temperature, something else has changed! Exhaust temperature is to some extent a symptom of efficiency, but is also a symptom of other factors.

The major factors that affect engine efficiency are:-

1. Combustion efficiency. This is the one that hydrogen fuel is claimed to improve. But in any modern engine, it is already very close to 100%, so any possible improvement is very, very small.

2. Thermal efficiency. (using this in a restricted sense, and is the largest loss of efficiency). This depends on the loss of heat through the cylinder walls (mainly depends on engine geometry and running temperature, both supposed to be fixed), compression ratio (fixed - this has the largest impact on exhaust temperature, and is why diesels have cooler exhaust), and combustion timing.Water injection can allow this to be advanced, and is the major area where hydrogen can improve efficiency - but the effect for the amount usually provided will not be measurable.

3. Mechanical efficiency. This comprises strictly mechanical losses (fixed), and losses due to gas flow (depends on geometry and valve timing, both usually fixed). Overall also dependent on rpm, lubrication, and operating temperature, all of which depend mainly on the driver/owner.

And of course, the major effect on fuel consumption that is not fixed by vehicle design is what we can call driving efficiency. This can be measured by the energy lost in heat from air turbulence, heat build up in tyres, and heat dissipated by brakes. This heat loss can be reduced by (respectively) lower speed to reduce loss to the air, higher tyre pressures and more suitable tyres to reduce tyre loss, and driving so as to avoid braking (look ahead and reduce speed by easing off on the throttle early, avoid slowing where this is safe). And then of course, before opening the driver's door, think for a moment - is this trip necessary?

John