In-cylinder fuel and lubricant effects on gasoline

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The purpose of the research reported in this thesis was to investigate the viability and quantify the potential gains of improving fuel economy of the gasoline engine through strategic application of additives. An increased awareness of the link between greenhouse gas emissions and global warming means that there is a desire to reduce carbon dioxide emissions from transportation. There is therefore a growing emphasis on improving the fuel economy performance of vehicles. The addition of friction modifier additives to the fuel is one way to achieve this. Using bespoke in-cylinder sampling techniques, an understanding of the operation of the piston assembly, a system responsible for much of the power loss in the internal combustion engine, is developed. Validation is given to the hypothesis that fuel economy gains can be achieved through the application of friction modifier administered to the engine via the gasoline. Results show gasoline administered friction modifier additive can accumulate in the piston assembly lubricant at levels 77 times greater than the initial fuel treatment level. The performance of a large number of friction modifier additives were uniquely screened in a novel bench-top test which simulated the arduous in-cylinder conditions found in a firing gasoline engine. The test generated vast amounts of information which led to high performance formulations capable of reducing the friction coefficient in both the boundary and mixed lubrication regimes by around 50% when compared with the result for the base oil alone. Surface analysis techniques were also employed 0!l engineering surfaces coated with friction modifier additives and add to the knowledge of their mechanism of action. Finally a series of engine tests were conducted which prove the effectiveness of friction modifier administered to the engine via the gasoline. A fuel economy improvement of approximately 2% was seen where friction modifier gasoline was employed. Application of successful technology such as this is shown to correspond to the projected saving of around 502 million litres of gasoline and 388,000 tonnes of carbon (C02) per year in the UK alone.

https://core.ac.uk/download/pdf/18451944.pdf
 
Some observations:

MoDTC doesn't work without a healthy dose of ZDDP or won't work for long. The reduction in zddp in todays oils is likely why we see less MoDTC aswell.

MoS2 in colloidal form does work in reducing fuel consumption
Quote:
The research explains that the technology of stable dispersions of solid lubricants, including MoS2, was at an advanced stage by the 1960's although the motorist found it difficult to quantitatively assess the 3% saving in fuel consumption resulting from the addition of MOS2 to crankcase oil.


Quote:
In the early 2000's, work conducted by the same authors shows the experimental technique was accurate enough to begin to differentiate between organic and Mo based friction modifiers, and research suggests that the Mo-type friction modifiers were about 0.5% more effective than their purely organic counterparts (Tseregounis and McMillan 2001).
 
texaco did some research aswell:

Quote:
Research showed the system to be instantaneously effective at reducing friction and that the friction reduction increased with time. The fuel economy benefits were independent of engine age or mileage, deposit level, model or brand although a decreased benefit was seen where engine oil friction modifiers were already employed and where high viscosity engine oils were used. Maximum fuel economy benefits of 4.66% were quoted to be achievable through the application of this type of additive technology.


They don't disclose what was used, but the additive was administered with the fuel. Key seems to be that the additive needs to have a higher mass than the fuel so it gets flung to the cilinder walls.
 
Originally Posted By: Colt45ws
Wow! 2% would be awesome! Where can I buy some? :p


It's a doctorate's thesis, they're not selling anything.
 
Originally Posted By: Jetronic
Originally Posted By: Colt45ws
Wow! 2% would be awesome! Where can I buy some? :p


It's a doctorate's thesis, they're not selling anything.

It was a joke. Hence, the ":p" at the end.
 
Originally Posted By: Jetronic
Originally Posted By: Colt45ws
Wow! 2% would be awesome! Where can I buy some? :p


It's a doctorate's thesis, they're not selling anything.


Maybe not literally, but the abstract comes over as a bit of a "pitch"

"strategic application of additives"

"bespoke in-cylinder sampling techniques"

"uniquely screened"

"vast amounts of information"

...strike me as marketing jive rather than academic language. Doesn't mean the results are [censored] though.
 
Originally Posted By: Jetronic
texaco did some research aswell:

Quote:
Research showed the system to be instantaneously effective at reducing friction and that the friction reduction increased with time. The fuel economy benefits were independent of engine age or mileage, deposit level, model or brand although a decreased benefit was seen where engine oil friction modifiers were already employed and where high viscosity engine oils were used. Maximum fuel economy benefits of 4.66% were quoted to be achievable through the application of this type of additive technology.


They don't disclose what was used, but the additive was administered with the fuel. Key seems to be that the additive needs to have a higher mass than the fuel so it gets flung to the cilinder walls.


You mean it separated from the fuel centrifugally? Doesn't seem very likely, since if it did that it'd settle out in the tank.

Presumably its less volatile than the fuel so maybe its left in the liquid phase as the fuel vapourises.
 
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Originally Posted By: Jetronic
it'll be more dense at the time.... which could be due to less volatility, but they did mention swirl and heavier...


Shannows link above says the same thing, more explicitly.

"However, but because fuel additives do not tend to change direction as quickly as gasoline, the additives still impinge on the cylinder wall,"

Still don't believe it, (and not only because illiteracy, as in "However, but" undermines credibility). Assuming the lube and fuel are miscible, they are both going to be present in mixed droplets and will travel together. They'll only separate by fuel vaporisation (and subsequent combustion).

I've just read through the dissertation literature review, to the start of the actual report "This thesis describes a seminal piece of research" (Seriously? Aren't OTHER people supposed to say that?)

That's as far as I got, but thus far there appears to be a bit of an elephant in the room (and maybe in the literature, if the review is representative)

"Compared to other areas of lubricant additive study, literature on organic
friction modifiers for automotive use is relatively scarce"

Oh yeh? Why are Castrol called Castrol then?

It could of course be that the literature doesn't reflect practice, but, as touched on above, this kind of thing is what 2-strokes do, and have done for a long time.

Surely there must have been SOME scientific investigation into how they do it?
 
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Some of the issues he mentions with fuel dilution on startup could be addressed by using gas (as in actual gas, not liquid fuel) for enrichment, so that's what I'm looking at this morning.

Model 1 off



Model 1 on



That volume of gas probably isn't going to make much difference to a car (though I have a 125cc motorcycle...?) so now I'll have to scale it up a bit.

giant-lighter.jpg


Note that I havn't described this as bespoke, unique or seminal (though if I use a giant lighter it'll be novelty-based) but y'all feel free.
 
Ducked,
look at this video, there's plenty of ideas that you can adapt here from butane to BBQ gas to propane.
 
Well, I tried it on the car



I decided to leave the clips and wing nut off so an explosion was "only supposed to blow the blahdy lid orf".

It isn't running at all well and probably needs the carb stripped and cleaned, which I'm putting off. It'll start on the lighter if its left long enough (gas probably pools in the intake) but then needs accelerator to keep it going. I suspect the idle circuit is blocked, so expecting it to actually run on a disposable lighter was a bit unrealistic.

VERY unrealistic if the sums I belatedly attempted are correct-ish

1 volume of n-Butane requires 6.5 volumes of Oxygen

http://www.bh-f.com/products/airgas.html

air is 21% oxygen (say 20%)

1L engine at 1000 rpm.

4 stroke so its pumping 0.25% of its capacity/rev ie 250mls.

So in a minute it shifts 250X1000 mls of air

i.e. 250 litres

a fifth of that is oxygen, ie 50L

So stochiometric combustion requires 50X1/6.5 L of butane a minute.

7.692 litres of butane

Model1a delivers 11cc in 20 seconds, so 33cc in a minute.



so it needs scaled up by a factor of 769/33, or 233X

Motorcycle only needs scaled up by 29X, and its idle circuit isn't blocked (or wasn't last I checked) so it doesn't need to actually run on it. Dunno how to calculate required volume to richen it though, so maybe just trial and error.

Am I off topic (and/or banned for life) yet?
 
Originally Posted By: Ducked
Originally Posted By: Jetronic
texaco did some research aswell:

Quote:
Research showed the system to be instantaneously effective at reducing friction and that the friction reduction increased with time. The fuel economy benefits were independent of engine age or mileage, deposit level, model or brand although a decreased benefit was seen where engine oil friction modifiers were already employed and where high viscosity engine oils were used. Maximum fuel economy benefits of 4.66% were quoted to be achievable through the application of this type of additive technology.


They don't disclose what was used, but the additive was administered with the fuel. Key seems to be that the additive needs to have a higher mass than the fuel so it gets flung to the cilinder walls.


You mean it separated from the fuel centrifugally? Doesn't seem very likely, since if it did that it'd settle out in the tank.

Presumably its less volatile than the fuel so maybe its left in the liquid phase as the fuel vapourises.


Bit more on this.

After I graduated, a long, long time ago, I worked as a research assistant in molecular biology, then in a period of rapid progress which I'm afraid I didn't contribute to at all.

One of the procedures used was buoyant density separation of DNA, which involved putting DNA in a solution of Caesium Chloride and spinning it in an ultracentrifuge for a very long time. The g force generates a density gradient in the Caesium Chloride, and the DNA concentrates in a layer corresponding to its density.

The centrifuge was spinning at 120,000 rpm for, IIRC, 36 hours.

Thats the sort of thing you have to do to use g-force for separation at the molecular level, and I don't believe anything remotely like it is happening in an engine.
 
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I tried turning the lighter upside down, thinking it might deliver liquid gas that way, but it doesn't seem to make any difference to delivery rate.

Meanwhile, back in the review.

Any comment on the surprising (to me anyway) lack of mention of the long history with castor and 2-stroke oils?

It could be:-

(a) oversight/doesn't see the relevance

(b) nothing in the literature (I think I've seen some, but I'm too busy [censored] about to search now)

(c) it would detract from the "seminal" pitch a bit.

Or a combination of the above.
 
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Originally Posted By: Ducked
Originally Posted By: Jetronic
Originally Posted By: Colt45ws
Wow! 2% would be awesome! Where can I buy some? :p


It's a doctorate's thesis, they're not selling anything.


Maybe not literally, but the abstract comes over as a bit of a "pitch"

"strategic application of additives"

"bespoke in-cylinder sampling techniques"

"uniquely screened"

"vast amounts of information"

...strike me as marketing jive rather than academic language. Doesn't mean the results are [censored] though.


It is a pitch. He's trying to get a doctorates degree. He's selling himself and his paper to get a degree.

I found a few things I don't quite approve in this paper aswell, but it does make a case for fuel borne friction modification.

Castor oil hashad a lot of attention, but it's definitely not suitable for continued use in passenger cars. Invariably, castor oil leads to gummed up rings.
 
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