100 MPG

  • Thread starter Thread starter Anonymous
  • Start date Start date
back up the page someone was talking about eliminating the plugs and suing compression-ignition, it's been done, called Homogonized Charge Compression Ignition (HCCI)

http://www.bourkeengine.net/

Also, and this part gets a little "witch-hunty", i've been using 3oz acetone/10gal gasoline for a little while now, and I must say the car really likes it, and my mileage has picked up a bit. before, i never saw over 30mpg on my '95 626 2.0 ATX, now i havn't seen under 30mpg.
just a heads-up.
Ern
 
Alvor315 you are right about gas coming out of suspension under pressure. Think about it though. In low throttle situations there is not much air let in to the cylinder so the pressure will not be high. When the pressure is high(full throttle), heat is added via compression pressure. The extra heat could keep things in a gaseous state. If not, it at least would be well mixed since it was probably mixed well when in a gaseous state.
 
Couldnt you just wrap a good steel fuel line near your exhaust manifold to pre heat your fuel? You would probably need to use brake lines since they are double walled.
 
Since the there is a lot of wasted energy from not burning the mixture completely maybe a very minute amount of nitros would complete the burn faster. If it were metered well it might extract enough extra energy to offset the added cost.

N2O has always been used to get HP but it has the desired effect of acelerating the burn rate.
 
BigPhill":3l5h1tpw said:
Couldnt you just wrap a good steel fuel line near your exhaust manifold to pre heat your fuel? You would probably need to use brake lines since they are double walled.
Click to expand...
thats roughly what some of us here are considering, the only problem is controlling the temp that the fuel reaches. too hot and itll burn as soon as it hits air in the manifold, not hot enough and itll leave residue. its a very precise balance
 
I guess we'd need to find the section of exhaust that is near the end point. obviously, the closer to the head would be the hottest, so maybe a foot or two away?
 
At work we have a piece of equipment that uses heated oil (600 degrees)
We are not currently useing it because it wouldn't run fast enough. If you would like I can see what type of oil/fluid it uses since it would work at the right heat without cooking the oil.
 
Stubby":29nixzg7 said:
At work we have a piece of equipment that uses heated oil (600 degrees)
We are not currently useing it because it wouldn't run fast enough. If you would like I can see what type of oil/fluid it uses since it would work at the right heat without cooking the oil.
Click to expand...
ive looked around and havent found anything capable of more than 3 or 400 degrees. if you could find out what fluid that it, that'd be great!
--josh
 
The fuel may be heated by the exhaust by constructing a valved diverter in the exhaust system. The valve would regulate the amount of exhaust gasses that heat the fuel, and could be controled by the fuel temperature and fuel flow.

Using electric or fuel fired heaters would be counterproductive to maximizing efficiency.
 
well, well, well - a couple weeks ago we got the electric heater instaled and fired up. it took several hours to heat it up to operating temp :( followed by an immense temperature spike and a pile of solder on teh ground. S**T...but that got us lookign around a little more...the solder we used has a melting point of 212*F - and the new plan is to use solder as teh liquid to conduct the heat. also, the heating assembly will be smaller and simpler, as the original was intended to be water-heated and now we're trying an electric-fired unit. looks like a great idea from here, i'm pursuing it
--josh
 
Most interesting subject! Being a Chemical Engineer and a bit of a car buff I have always thought through a few ideas to improve fuel economy. As yet I haven't had the opportunity to test them out but my knowledge of petrochemicals and the some of the reference texts I have may be of use here. I can find a diagram for you that gives the volume vaporised against temperature for a motor fuel, if you like. And will list some of the data points when I get the chance. I can also give you the vapour pressure curves for the most common hydrocarbons. One of the reference texts I have contains a LOT of information of the various species, such as butane, pentane, hexane, heptane, octane.....and so on.

One problem is that, as pointed out, most fuels will be a mixture of thousands of components. There will be a few that will make up the majority, but the cracking reactions at the refineries create a myriad of different rearrangements of the hydrocarbon chains.

If there are specific questions you would like to ask me, as a Chemical Engineer who believes MUCH greater fuel economy is and should be possible, then fire away. I'm not sure 100mpg is possible, but at the same time, it should not be discounted. I have read, and had email dialogs with one inventer here in Australia who claims to have achieved 50-60 mpg with a 1998 Falcon. I have no doubt to not believe his claims, and he even sent me a CD with a lot of his photo's and infomation on it. I'm still sifting through it but it all seems to be plausible.

Regards,

Teddy :)
 
Here some volatility data I dug out of one of my texts in regards to percent volatility against temperature.

% Volitility : Temp (°F)
0 : 60
5 : 110
10 : 135
15 : 155
20 : 165
25 : 170
30 : 180
35 : 188
40 : 195
45 : 200
50 : 208
55 : 215
60 : 222
65 : 230
70 : 240
75 : 255
80 : 275
85 : 295
90 : 320
95 : 355
100 : 400

Now if you plot this data in something like Excel, with the %Volatile on the x-axis and the temperature on the y-axis, you will see a curve that rises fast (the light fraction of the fuel) steadies to a constant rise then rises sharply at the end (the heavy fraction of the fuel). Keep in mind that this is only a guide. Each fuel from the refineries will be different, and the fuel "signature" curve will also change over time. The fuel from 10 years ago wont neccesarily have the same curve today, even if its from the same refinery. The refineries make fuel to set standards, as long as they meet those standards, by whatever fraction of hydrocarbons they have, they're OK. This particular data will be over 10 years old, but I would still expect the general trend to remain. With a bit of simple equipment, it wouldn't be too hard to actually make up your own %volatility versus temperature curve for any fuel you can get your hands on. Only thing is, you must be very careful because the hydrocarbon vapours are extremely flammable, and in the right set of conditions, you could form a fuel air explosive device.....not something to take lightly.

Anyway, hope the above info might be of some use, even if only to demonstrate some of the general natures of the fuels we deal with.

Regards,

Teddy :)
 
It looks like if you heat the fuel with coolant(200 - 220 degrees) your guarenteed to have at least 50% of the fuel vaporized by the temperature alone. Of course for a carb this would probably a vapor lock issue. Where the heating would seem to help the most would be in fuel injection where the fuel is pressurized and there for more likely to stay a liquid until released at the injector. If the incoming intake air is the same or higher pressure, it seems that much of the fuel will vaporize simply because of the temperature. The rest would atomize as it normally does in an injection setup. The most bang for the buck on an injection system may be to run the metal fuel lines through coolant on its way to the radiator. This would be the hottest point in the coolant flow.

ASmart
 
I have seen some designs for a fuel heater using engine coolant, before it is fed into the carby. By restricting the coolant flow, you can limit how hot your fuel gets. One reference I've seen said you could heat the fuel to 150-160 °F before vapor lock started causing problems, but that sometimes you would have to limit that to 120 °F. IIRC during the winter months the refineries will (or used too) purposely add in some of the lighter fuel fractions to help in the starting and running of vehicles in general. That need may not be so pronounced now that fuel injection technology rules the roost, so-to-speak. Any sort of heating is bound to improve the running of the motor and improve the fuel economy.

One of the reasons I have seen put forward as to why there are such persistant rumours of extremely high milage from days gone by is that for the fuel produced back then, it was true. The fuel produced 50-60 years ago was quite different than now. Back then there was a lot of straight-run, straight-cut?, gasoline, which means there was a lot less variation in the boiling temperatures of the fuel. As my last post showed, there is quite a range of boiling temperatures in modern gasoline. But in the past, a vapour carburetor would have worked well because the boiling temps were less broad, so that depending on how things were set up, heating the fuel to temperature X meant that you could still meter it through a carb, but that the vacuum it experienced after that point resulted in produced a vapour. Lets face it, if you could extract a very tight boiling range of hydrocarbons out of normal gasoline, you would heat it just enough to give you the best running without vapour lock becoming a problem. As it stands, anything we do in heating the fuel (for a carby set-up that is) will be a compromise.

Appologies that my posts have been rather long, not meaning to swamp the thread with information. I'll shut up now and listen for a while. But given that the price of oil is starting to climb again, I think this discussion thread is going to be of huge intrest to many others out there.

Regards,

Teddy :)
 
I built a fuel heater, using engine coolant as the heat source, to try to separate light ends from heavy. I used a 195 thermostat to maximize heat. What i found mirrors the numbers posted. At that temperature I was able to vaporize about half of the fuel.

I ran the vapors through a condensor and then to a tank. I was going to then run through a standard carburetor, preheating the air to 200+ degrees.

I was hoping for a much higher percentage of vaporization. If I put the vaporization chamber under vacuum, say 15", would it have a significant effect on the percentage of fuel vaporized?

My goal was to lower the endpoint of the gasoline to achieve faster burn. Also, running a higher compression to take advantage of the lower endpoint while creating a still faster burn.

Does the 200 degree end point fuel I end up with now somewhat resemble the fuel of days gone by when guys were claiming to get 100 mpg? I'm wondering, with this fuel and an engine with a compression ratio of somewhere around 12 - 14:1, and reduced advance on the timing to take advantage of the faster burn, can I get fuel mileage results to make it worth while? Including a 50 percent loss in fuel?
 
the main problem with using coolant as a heat source is that, because it is not hot enough to vaporize the heaviest parts of the fuel, those heavy parts will build up as a residue and clog your heating system. some of my past posts have described teh system that is in process here, but i will briefly describe it again s we're all on teh same page.
the system was an oven with a coil of copper tube inside, which carried the fuel that is to be vaporized. the problem with this system was that air is a very poor conductor of heat, so it took several hours to reach the desired temp of about 475F. but we got it up to temp, after waiting all day, and then the temp spiked. FIRE (inside). what happened is the solder connecting the tubing melted, releasing fuel into hte air in the oven, and in the presence of a red-hot heating element, it flashed.
this produced teh question of the solder's melting point. 212F. thats low - thats where water boils!! now we had always wanted to have a liquid to help with heat transfer, but couldnt find anything capable of the temps. well it was right before our eyes the whole time. solder.
so now we have to find a way to make all this work

the system has always been intended to heat the fuel in teh absence of air, thus limiting any fire hazard to being within the intake manifold.
also, the fuel delivery will be some form of mechanically-controlled throttle body injection. in other words, the carby becomes a throttle body with a link to the fuel valve, which enters a vacuum port on the manifold.

i apreciate the data, and as for the length of your posts, in this forum i consider it a good thing.
--josh
 
My intent was for the heavy ends to remain a liquid. I wanted to separate them out. I thought that a much higher percentage of fuel would evaporate at 195 degrees.

A question for Teddy, or anyone else who has the answer. Why is it that only 50 percent , more or less, will evaporate at 195 degrees, but an open jar of gasoline will evaporate until nothing but varnish is left?
 
dcook":3uh4odgc said:
My intent was for the heavy ends to remain a liquid. I wanted to separate them out. I thought that a much higher percentage of fuel would evaporate at 195 degrees.

A question for Teddy, or anyone else who has the answer. Why is it that only 50 percent , more or less, will evaporate at 195 degrees, but an open jar of gasoline will evaporate until nothing but varnish is left?
Click to expand...

The reason that all of the fuel will evaporate is a two-fold effect. First, even the heavy ends of the fuel have a reasonable high vapour pressure at moderate temperatures, ie. there is always some of that hydrocarbon in a vapour above the main liquid. Say that at ambient temperature, the vapour pressure of a particular hydrocarbon was 1" of mercury ( 1 atmosphere is approx. 30" of mercury.....its just a measurement unit). In a sealed container, the atmosphere will approximately contain 1/30 th of the hydrocarbon. But in the sealed container (fuel tank), it can't go anywhere. This is the second part. The vapour above the hydrocarbon liquid always wants to remain in equilibrium with the liquid. The amount of vapour above the liquid is dependant on temperature mostly. In an open jar, the gasoline vapours can escape into the air and be completely removed from the liquid. However the system always trys to maintain the equilibrium, so, more hydrocarbon will evaporate to try and compensate. In this way the liquid will eventually be completely evaporated.

Although you evaporate half of the fuel at 195°F, you are effectively dealing with a sealed system, so the vapours (unless you allow them to) can't escape. But you can bet your bottom dollar that if the vapours from the heavy ends can find an escape route to the atmosphere, you'll lose the heavy ends to evaporation also.

Hope this isn't too technical and that you followed it OK.

dcook":3uh4odgc said:
Does the 200 degree end point fuel I end up with now somewhat resemble the fuel of days gone by when guys were claiming to get 100 mpg? I'm wondering, with this fuel and an engine with a compression ratio of somewhere around 12 - 14:1
Click to expand...

Be careful! At those compressions you may have serious detonation problems. The one advantage of modern fuel is that it is a lot more knock resistant than fuels of days gone by. The many different branched hydrocarbons in our fuels are better for resisting knock in a motor. The straight cut gasoline of 50-60 years ago may only of had an octane rating of 60-70 RON (bit of a guess, but it was certainly lower than today)



dcook":3uh4odgc said:
I was hoping for a much higher percentage of vaporization. If I put the vaporization chamber under vacuum, say 15", would it have a significant effect on the percentage of fuel vaporized?
Click to expand...

Vacuum would help, would have to look a some numbers to know how much. I should reiterate at this point that I know and have had conversations with an inventer here in Australia who used exhaust heat to fully vapourise the fuel. The whole air/fuel charge was heated so that the fuel was fully vaporised and the heated air meant that the fuel remained as a vapour. Mileage was in the 50-60 mpg range for an 1998 Falcon.

One idea I have been toying with is very similar to your idea, that is to use the engine coolant to split the fuel into different fractions. The light fractions could then be recondensed and used as is, the heavy fraction would then be used in conjunction with heating before they ended up in the carby. With the light ends, requiring minimal heating, they should vapourise well once through the carby into the higher vacuum of the manifold. The heavy ends will need to be heated. But if you've already split them at about 195°F, then you know that you can use engine coolant to heat the heavy ends as much as possible, and there shouldn't bee too much problem with vapour lock. Once the hot heavy ends hit the vacuum of the manifold, they too would hopefully turn to vapour. The way you get to use all the fuel, not just 50%.

Oh dear, it appears I've rambled on a bit here again, time for me to be quite again for a while. (can you tell I enjoy this sort of topic :lol: :lol: )

Regards,

Teddy :)
 
1. I am not sure I understand why the seperation or the heavy 1/2 and the light 1/2 helps. If you condense the ligh 1/2 and using that, aren't you reverting back to the same state as it was before you seperated it?

2. I was thinking that if you used fuel injection, the heated fuel would be under pressure. If it is 200 degrees, at least 1/2 of the fuel will be at a temperature that would be vaporized at atmospheric pressure. The pressure in the fuel line would be above that so iall the fule would likely be a liquid still. This would allow the FI to work as it normally would with no modifications. When the heated fuel hit the manifold it would be entering an environment that was below atmospheric condotions. That would mean the light 1/2 plus some of the heavier 1/2 would likely vaporize due to the temperature and the below atmospheric pressure. This would be especially true at part throttle. The rest would "atomize" and be drawn down the intake as a mist. The worst case would be some puddling of fuel on the intake floor as with a carb or throtyle body injection. The puddling would be minimized due to the 200 degree fuel. Lessen the chance of puddling with hot intake air and a hot intake.

"fuel for thought"
 
In my first experiment the pressure in the fuel heater was at atmospheric, or slightly above. What I am planning to do next is to use a mechanical fuel pump that also has a vacuum pump, from the old days of vacuum wipers. I plan to use the vacuum pump to draw the vapors out of the fuel heater, through a condensor, to the vacuum pump and then to a tank.

The reason for condensing the vapors is this - others have tried to vaporize the fuel and then deliver it straight to the engine. There is a metering problem. By condensing the fuel, and then running it through a conventional carburetor, I can effectively meter the fuel. By heating the incoming air to above 200 degrees, I am assuming the the fuel will again vaporize as it enters the venturi and the intake.

As for compression ratios, eliminating the heavier ends in the gasoline and the faster burn 'should' make it do-able.

I have everything to put this together. But my confidence in the theory wavers, so my motivation suffers. I think my compression will be more in the 11 or 12:1.
 
You must log in or register to reply here.
Back
Top