HHO Gas Cars

[Meta menardi]

With the inspiration of this thread, I popped out and got all the wood ash from the back garden, and now I have a magnificent oak dining table.

[Jim Ford]

Brilliant - and in the process you've sequestrated some carbon from the atmosphere, helping save The Planet!

Jim

[eeyore]

Originally Posted by Meta menardi

With the inspiration of this thread, I popped out and got all the wood ash from the back garden, and now I have a magnificent oak dining table.

and for his next trick, a visit to the local sewage works to prepare a meal for 4

[gonrod]

Ok, there is a heck a lot of confusion here quite obviously. But first let's get two things straight. First water can be used to improve the efficiency of an internal combustion engine, second it's got nothing to do with the HHO scam.

Let's look at some facts.

First to separate the oxygen and hydrogen in a water molecule takes energy. That energy comes from somewhere, and in electrolysis it's from electricity.

When you perform electrolysis on water or anyhting else, part of the enegry goes into a number of other unavoidable processes which among other things make the water warm! So even if you burn all the hydrogen, you won't get all the energy back.


Also, energy has been lost heating the wires that delivered the electricity to your house, and there have been losses involved with burning the fuel at the power station, and most of those burn fosil fuels anyway.

However, looking at the efficency of large electricity generating plants, that is a more efficient way of burning fuel, but that does not mean you will save money, because you still have to deal with the appalingly low efficiency of the internal combustion engine.

In theory, if we had perfect engineering materials available, and we could totally eliminate friction, then a four stroke engine has a theoretical maximum of about 70%. In the real world it's more like 17% A huge loss to friction, you might think, but of course the average engine in practice departs somewhat from the theoretical ideal!

So rather than changing to a different fuel, which will have no effect on the efficiany of the engine, you rather need to look at making the engine more efficient in some way. This is where water comes in.

The theory which tells us that the engine can only be 70% efficient at best shows us that a big part of the problem is waste heat. 30% of the fuel's energy is thrown away as hot exhaust gases. If we could get that back, it would help quite a bit.

There are a number of engine desings in laboratories that use the exhaust heat to boil a mist of water in an extra power stroke. Thermodynamically speaking we have reduced the exhaust heat by lowering the temeprature of the exhaust gases by a couple of hundred degrees. From the typical three or four hundred degrees centigrade to one hundred degrees. That means more energy has been extracted. (Porvided it's not just vented off as waste steam etc. But that would be another 'exhaust' you would need to account for!)


In effect they are a hybrid petrol/steam engine. They still suffer the same sort of frictional losses but they can make a marked difference to the energy extracted from the fuel.

It is probably the existence of this type of experimental engine which is used to confuse the issue. Water using engines do exist in the lab, they are more efficient, but they do not burn water, and do not improve fuel combustion. Just make use of stuff we are currently throwing away.

So why are we not seeing them in new cars? Well basically there are two problems.

First no one has figured out a way of getting water pure enough that it does not furr-up the injectors, and which does not use as much energy as has been saved to purify it Second the materials that we understand well enough to build an engine that will not fall to bits in a relatively short time will corrode when exposed to liquid water. (The high operating temperatures of engines is too high for water to exist in liqid form in the places which are nmost vulnerable to water damage.)

Injecting water into your air intake over an extended period will damage your engine for much the same reasons. Though is should be noted, that spraying water into a running engine can sometimes be partially effective in removing combustion chamber deposits. If anyone has seen any improvement in engine performance by doing this, that would be the reason. That is to say your engine is in serious need of a de-coke, and running even more inefficiently than normal. So get the spanners out!


Another problem is that most engines which use the steam generation technique involve an extra cylinder, and are more expensive to make. But some just require a new type of cylinder head and camshaft as the steam is generated on an extra stroke. But the corrosion probelm still persists.

Interstingly there has been an engine around for over a hundred years which without using water also utilises the exhaust heat to increase efficiency, achieving theoretical efficiencies in excess of 90%. It's called a Stirling engine.

Unforunatley the stirling engine uses a complicated arrangement of cranks, and concentric pistons etc, to achieve a complicated operating cylcle. Not really a practical proposition for a car engine, although static sterling engines have been built. (We had a small demo ennine at school which would happily chug away on the amount of heat generated by a small torch bulb!)

So much for the thermodynamics, but that's not the only story.


A heck of a lot of energy is wasted in friction. Not just by way of parts rubbing together, but oil needs to be forced through narrow pasages in the engine, at considerable pressure, which uses an apreciable amount of power in fluid friction, and other systems also suck power from the engine system. By far however the biggest loss is due to friction between the pistons and cyliner walls.

If you think about this for a moment, you have a large lump of alloy, with a large surface area rubbing up against a large iron (usually) surface which is the cylender wall. As if this was'nt enough there is a considerable side force coming from the angled conecting rod pushing the piston against the cylinder wall!

Racing engines use very short pistons, which reduce the surface area and hence friction to reduc this loss, but we all know that these engines need to be stripped and re-built after only a few hundred miles, or they blow up. Not rally a practical solution for the everyday car. (Though some 'boy racers' do it, but exactly what good it does in a 73' ford cortina I have no idea!)

There is a new engine design however that the inventors claim to eliminate most of the side force by eliminating the crank shaft, and replacing the conrod with a rigid beam. The linear motion of the piston is transferred to the shaft by means of two counter rotating multi-lobed cams working against a pair of rollers fitted to the piston beam, arranged so that the recation tourque of one cam is balanced exactly by the other.

This it is claimed virtually eliminates side thrust, and so reduces the friction by an enourmous amount. Also they piont out that the piston now requires no skirt at all to keep it straight in the cylinder bore and to spread the side thrust load, further reducing friction.

This engine they claim burns only 60% to 70% of the fuel of a conventional piston engine, (which is about 50% more mpg in road terms.) and requires no special materials of manufacturing teqniques. It is also pointed out that as they can choose the cam profile, the piston motion can be bery accurately controlled so as to provide a much closer approximation to the theoretical ideal, or conversely, trade efficiency for power, or engine longevity etc.

Having said all of the above, it won't make a tad of difference if people will insist on buying the biggest heaviest vehicle they can afford! Lugging un-necesary weight around, and pushing more air out of the way than you really need to in order to get around, is a great way of reducing the efficency of any mode of transport.

Let's face it, if it's jut you getting your bod about town quickly, you can do 25Mph on a level road on a pushbike, and when did your average town driving speed average that?

Personally I drive a Citroen AX, on which I just rebuilt the cylinder head and gave it a proper de-coke. It's now driving like a new car, and getting 50Mpg on an urban cycle. On motorways, I'm told (I haven't tested this one out yet!) I can get 80Mpg if I don't insist on caning it. And in truth it does not seem to matter how I have driven in the past, on UK motorways an average of 50Mph is about the best you can usually hope for, and going much over 60Mph just gets you to the next traffic jam that bit sooner.


So doing stuff with electricity to your water will not make your petrol burn better. It's pretty well completely burnt already, and what you get for your trouble is at best a bigger electricity bill (more per KW.hr than petrol gets you) and if you are unlucky a serioulsy wrecked engine.

So don't go there. It's a scam, snake oil, whatever you want to call it, it does not work!

[loruschorus]

That's got to be about the longest post I've ever seen, gonrod - it's quite good though! With respect to the HHO nonsense, the closest I've ever heard of was shown on the BBC website I'd guess about 6 weeks ago. Essentially, a gentleman had created a port-a-loo sized water->hydrogen device, that would give about 30 miles worth of hydrogen a day. A pity then that he didn't have a hydrogen fuel-celled car in which to put it - I believe it was a design that he hopes to market as these cars become common.

As a point of interest, an internal combustion engine can be made to run on hydrogen rather than petrol as demonstrated on the American television series 'Mythbusters', where they blew hydrogen gas directly into the carburettor. It ran for several seconds before the excess hydrogen in the engine bay ignited.

Jeff

[Jim Ford]

Originally Posted by gonrod

Personally I drive a Citroen AX

Hmm, you show that you know quite a bit about thermodynamics and reciprocating engine design, but then let yourself down by revealing that you own a Citroen - a car that bears the name of a type of lemon!
;^)

Jim

[Meta menardi]

Originally Posted by Jim Ford

Hmm, you show that you know quite a bit about thermodynamics and reciprocating engine design, but then let yourself down by revealing that you own a Citroen - a car that bears the name of a type of lemon!
;^)

Jim

"Citroen" is French for magic carpet. A lemon is a Pamplemousse, but only if it is a grapefruit.

Oh and by the way, Gonrod, a very hearty welcome to the home of all wisdom that the members know about.

[Jim Ford]

Originally Posted by Meta menardi

"Citroen" is French for magic carpet

We're in England - and it's a lemon!
:^)

Jim

[gonrod]

En français, le mot pour le "Lemon" est le "Citron".

Citroën – named after André-Gustave Citroën (1878-1935), a French entrepreneur of Dutch descent. He was the fifth and last child of the Dutch Jewish diamond merchant Levie Citroen and Mazra Kleinmann (of Warsaw, Poland). The Citroen family moved to Paris from Amsterdam in 1873 where the name changed to Citroën.


As for why I drive a Citroen?

Well, unlike many drivers who buy first and rationalise an excuse later, I sat down and spent a couple of weeks researching exactly what car would best suit my purposes. I live in Brightin, where parking is a nightmare, and regulary have to attend auctions, and the cars are usually wedged in three or four deep, with no room for manuever. Citroën AX is a good foot narrower than most cars, and is built like a mini-estate too. (It's amazing how much stuff you can get in the back with the seat down!)

When the engine is nice and clean, and has been (properly run in which mine has!) you get 50Mpg urban, and more on long-haul journeys. (Over 250 miles per stint) Ok at 60Mph, but as I said in my earlierr post, I have found that the difference between a steady 55Mph, and 85Mph in terms of journey time is minimal on UK motorways. A few minutes at most. Also the engines start first time, always, (Provided you have an injected model!) and with the all alloy engines are lightweight, and very nippy in towns and great for country roads too.

Not to forget they are corrosion proofed at the factory, and if mine is typical this is very well done, not showing any significant corrosion at all, despite spending 90% of it's 16 years at the seaside!

Downsides.

OK the trim is basic, and a bit flimsy but to be honest, that's not high on my list of priorities. The bodywork is also a bit on the lightweight side, and bumpers are prone to fall off under impact. (But cable ties will hold a loose bumper very reliably!) A plus on the weight side is that if yiu get "sideswiped" the car tends to get out of the way rather than crumple. Someone did this to me not so long back, and despite ruining a perfectly good rim, (and knocking both bumpers off!) the car survived virtually unmarked. (And the bloke drove off, without giving details. The police tell me that the owner claims his mate was driving, of course his mate deny's this. Not that it will matter to the insurance companies!)

Engine wise, mine's got the 1125cc wet-liner single point injector. These have a tendency to leaky head gaskets, especially if you try and run the thing on cheap supermarket petrol and let it get badly coked. On the other hand, you get lots of warning, and you don't end-up with a sump-full of mayonnaise, which does the engine bearings no good whatever. So an extra 1p a liter is worth the extra just to avoid the hassle.

(If you need to get the cylinder head gasket replaced it's easy enough to do yourself, and better. The garage will set you back about £400 and will not do anything other than just replace the gasket. (and probably skim the head.) Doing it yourself, will cost about £150, including most of the tools you will need, a full top-end gasket kit (including new valve-stem seals), the price of a "dressing skim" (About a thou, just to remove any pitting due to corrosion cause by exhaust getting into to coolant. £25 cash at your local motor engineers), and you can give it a good de-coke so that the engine will perform better, and reduce the risk of a repeat performance in the next three or four years. Tip...Make sure the gasket has separate fire rings. The cylinder liners are not always exactly the same hieght, and liners with a continuous fire-ring don't have as much "give" in them and so tend not to seat as well.)

Other than that, its cheap to run, just make sure you use the right coolants, change the oil regularly (I use a fully synthetic. More expensive but the car loves it!), and lay of the cheap liqour and you should be fine. If you develop a bad pink, expect gasket failure in the next year or so. Mine does not pink at all since de-coking!

And, it cost £350 to buy, with a new MOT, and road tax almost two years ago. After selling the totally excessive in car sound system, I reckon that I actually paid about £110 for it.

On the subject of running a car on Hydrogen.

I didn't say you couldn't. Hydrogen makes an excellent fuel, but...

First, you have fuel storage prolems. Hydrogen needs to be under considerable pressure in order to get enough into a reasonably small tank. So a heavy tank is required, and you would not want it to rupture in an accident!

Second, we have no idea what the result of hydrogen 'spillage' will do to the atmosphere, and if every car in the world were running on it, the amount of inevitable spillage would be considerable. Don't forget we thought CFC's were completely inert, and therefore totally safe until the ozone layer developed a big hole. We know that hydrogen is not inert. We should be cautious before jumping on the hydrogen waggon.

(Ok, it produces no carbon dioxide at the tailpipe, which is the green bogeyman gas. But if we burn fossil-fuels to make the hydrogen then all we ar doing is moving the carbon dioxide release to a different place. More efficient turbines can burn less fossil fuel for the sme power output, but then as I said before, we cripple this by then using it to produce a hydrogen, which is then inefficiently burned in a car engine. So we introduce an extra loss at the hydrogen plant, and use more energy for the same number of miles travelled!)


Third, it is not cheaper than pertol. Certianly you can build a hydrogen electrolysis plant at home, but that won't get you cheap motoring.

Lets do a quick calculation.

If we assume your hydrogen generator will use all of it's input energy into separating the oxygen and hydrogen. (It will not but let's just assume it does.) Then each Kwh will produce enough hydrogen to provide one Killowatt of power for one hour. Your average small car running in it's most efficient mode (55Mph continuous speed.) will run at around 45Kw. So after 55 miles you will have used 45Kwh of energy.


We can equate that to energy cost by looking at our electricity bill. My last bill shows I paid 11.78p (cheap rate) for each Kwh. So that equates to 11.78 x 45 = 530p or £5.30 . Petrol is costing me £1.11 per liter, and so I get 4.78 litres for that amount of money. A UK gallon is 4.454 liters so that's 1.07 gallons.

Now in my car, that get's me something close to 75 miles under the same driving conditions. So I get 75-55= 20 miles more out of my petrol, than by electrolysing water to get the hysdrogen. And that's if I'm running with a 100% conversion factor from electricity to hydrogen.

Ok, so I get a more Mpg out of my car than most. But that does not mean a thing. If you have a car which gets fewer Mpg, then you will burn more hydrogen per mile too. I just used my car as an example.

Of course, if the price of electricity came down to arounf 8p pew Kwh you could argue that there was a break even point, but again I stress, that this calculation assumes 100% conversion efficiency. In reality the best you can expect is 50%. Even the latest experimental conversion equiment can only achieve about 80% at ver low yields, and not practical for generating the amount required for runing a car on a daily basis.

Also, the hydrogen has to be comressed, or liquified before you can cram enough into the tank for any practical use. Compression requires power, and so does cooling.

Ok, if you live somewhere cold, the waste heat produced by these processes could be used to heat your home, or provide hot water, but I'm willing to bet few people are going to go that far, and of course not many people live in places cold enough for that to be practical all year round!

So allowing for a real practical converson efficiency, that £5.30 is more like £10.60and you are only getting 55 miles from that, and that's in my car runing under ideal conditions. If a large SUV gets say, 25Mpg under the same condiditons, then you can multilpy that by a factor of three.

The fact is that fossil fuels are really dirt cheap, and have historically seemed plentiful. Governments worldwide all realise that in reality the available reserves of oli and gas are limited (whatever they say) and realise that one day pretty soon they are going to run out. When I say run out I mean literally run out. No amount of technology is going to be able to extract oil that is not there.

Before that however, what oil remains is going to cost more and more to get out of the ground, and relying on simple free market economics to take care of the problem will not work. That's because free markets do not generate investment until after the prices have increased naturally. That's not fast enough, and has the obvious problem that before anything happens, we won't be able to afford it in any case. (So a strong risk of total energy market collapse, etc.) So not good.

So getting people to think now about the cost of energy before we end up in a lose-lose situation, I think is a sensible approach. Artificially increasing the cost of petrol to a point where unit for unit the various forms of energy delivery cost roughly the same, is one way of ensuring that what people concentrate effort on is improvements in efficiency, or 'free' energy tecnologies. (Such as solar or wind generation.) This is dome by taxation.

Don't let yourself be fooled by the notion of the greedy tax-man either. Governments well know that you can only extract so much tax, and realise the importance of transport in any economy. So you should rather think about why the tax on petrol is so high in terms of what they are trying to convince us to do, rather than in terms of lining the chancellors pocket.

(And no I don't like paying taxes either, or necesarily agree with all the ways it is spend. I don't expect other people to agree with some of the things I think tax money should be spent on either. It's called civilised society!)

It is interesting to note that many of the people who really seriously try and say there is plenty of oil to last the human race, are christian fundamentalists who also beleive that the apocalypse is just around the corner. By their calculations there is just enough oil to last until judjement day, probably calculated as sometime around 3Pm next Wednesday!

[Jim Ford]

Originally Posted by gonrod

I live in Brightin

Taxi drivers know a thing or two about reliable, long lasting cars that are cheap to run. What cars are most favoured by taxi drivers in Brighton?

Jim