Etanol.nu

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InläggPostat: mån 07-06-11 11:57 
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From:
http://www.turbofast.com.au/racefuel2.html

Citat:
This is a fuel with a large cooling effect provided by part of it evaporating after it has reached the combustion chamber and so tending to cool the valves, piston and so on.

Some may well get into the combustion chamber as liquid, due to the reduction in temperature of the induction system, pipes, carburetor, etc., and so extending the cooling effect, in the process counteracting the effect of the high internal temperature.

In view of this amount of fuel entering the chamber, with possibly some of it in liquid form, the ignition system must be beyond reproach since if the spark is weak the mass of fuel will just soak the plug and then at once ignition troubles arise affecting starting in particular.

Owing to the use of alcohol a higher compression ratio can be used with this fuel as compared with petrol, another consideration is the type of plug used which will be a hotter type than used before with petrol.

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InläggPostat: tis 07-06-12 22:20 
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I tend to agree with Volvo-Berti that the evaporation heat of ethanol is not important in making an engine run cooler on E85 than on gasoline. For gasoline the evaporation heat is about 0,74% of the heating value of the gasoline. For E85 it is 2,75% of the heating value. Such small values cannot explain the observed effects. The reason for running cooler on E85 is the lower irradiation losses from the less luminescent flame compared to the gasoline flame.

In high power operation with rich fuel mixtures it is the non complete burning causing large amounts of CO (carbon monoxide) instead of CO2 (carbon dioxide) wich lowers the temperature but instead increases the number of gas molecules produced per original oxygen molecule in the air which enables the higher power without overheating.

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InläggPostat: ons 07-06-13 12:57 
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aryan skrev:
Another less theoretic way to see that the engine burns cooler is to measure the time it takes before the engine obtains normal working temperature, this takes longer time unfortunately it also takes longer time after start before the catalist starts to work becasue of the lower exhaust temperature.

no, it seems to me that my car even reach the normal temp faster, since i drive with alcohol. (the water temp instrument shows that)

aryan skrev:
Another obvious proof of lower exhaust temperatures in winter is that the exhaust gasses condensate in the tailpipe (much longer after cold start) and in winter you always see the white steam coming out of the exhaust where petrol/gasoline driven cars have hotter exhaust gasses and no visible condensation of the exhaust gasses.

the reason for that is the higher water part in the exhaust gas. just simple: driving alcohol = more fuel consumption = more exhaust gas, combined with more water steam parts. :wink:

aryan skrev:
I think this condensation might shorten the lifespan of the exhaust pipe somewhat (unless it is stainless steel) although you will get hardly get any agressive sulfuric acids in the exhaust gasses from ethanol, but on the other hand the levels (much milder) acetic acids will be much higher from an ethanol engine./Aryan

yeah, this is what i suspect, too. But until now my exhaust pipe is in a good condition after driving two winters under ethanol. so those acetic acid is not a problem, even no sulfuric acids. these ones will not only attac the exhaust pipe, but the engine's oil. during the cold start phase the burning (esp. in winter months) is not complete, means that not only CO2 and H2O are burning products!
if we use methanol instead of ethanol, there could be a drift of formic acid into the oil, which is a much bigger problem than the low acids in the exhaust pipe.
so Ford gives a hint in the manual of their FFV to change the oil every 10.000 km, in not FFV the intervall is 15.000 or 20.000 km.

karlmb skrev:
I know of the E-marking.
But I'm not sure that it's needed anymore......Maybe the German authorities are more strict.
yes, they are. :roll:
karlmb skrev:
Can you please point us to the authority in charge of this matter in Germany so we can clear it out thoroughly?

hm, i just do not completely understand....i try: you want a link to read the german laws to get information? okay...
main site lists all laws and orders of "traffic law": http://www.verkehrsportal.de/gesetze/gesetze.php

this site describes the condition of a car must have in Germany, if you will drive it
the ABE wich i meant is §20, the §22 is about the "operating licence for parts" and 22a "construction licence for parts"

sorry, but i cannot translate that very compllicated material into English :(

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Volvo V70 II on 30% E85 (just for starts) and LPG
Berti
http://www.ethanol-tanken.com
http://www.spritmonitor.de/de/detailansicht[url]/349366.html[/url]


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GL skrev:
I tend to agree with Volvo-Berti that the evaporation heat of ethanol is not important in making an engine run cooler on E85 than on gasoline. For gasoline the evaporation heat is about 0,74% of the heating value of the gasoline. For E85 it is 2,75% of the heating value. Such small values cannot explain the observed effects. The reason for running cooler on E85 is the lower irradiation losses from the less luminescent flame compared to the gasoline flame.

In high power operation with rich fuel mixtures it is the non complete burning causing large amounts of CO (carbon monoxide) instead of CO2 (carbon dioxide) wich lowers the temperature but instead increases the number of gas molecules produced per original oxygen molecule in the air which enables the higher power without overheating.


A known fact is that the cooling effect from the fuel is very important.
This can be understood if you try to run any std petrol car or a two-stroke on too lean mixture at high power output (no problem with ethanol..).
There is a fine line between enough cooling of the most critical parts as piston crown and valves, and a disaster.
With ethanol as a fuel, according your own figures, the cooling effect is 2,75/0,74 = 371% larger when the same heat energy is burned.

Ofcourse this is positive when it comes to protect the engine and exhaust parts.

About the CO-production from ethanol, where did you see this explained?

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karlmb skrev:
A known fact is that the cooling effect from the fuel is very important.

The interesting thing is just what makes rich fuel/air mixtures burn cooler, especially for gasoline the evaporation heat is simply too small to be of importance.
Citat:
This can be understood if you try to run any std petrol car or a two-stroke on too lean mixture at high power output (no problem with ethanol..).
There is a fine line between enough cooling of the most critical parts as piston crown and valves, and a disaster.
With ethanol as a fuel, according your own figures, the cooling effect is 2,75/0,74 = 371% larger when the same heat energy is burned
Ofcourse this is positive when it comes to protect the engine and exhaust parts.

371% sounds a lot but the absolute value is still too small. The much more important factor when running at high power with lean mixtures is the lower flame speed, at least for gasoline. This could make the burning extend too far into the exhaust phase leading to overheating of the exhaust valves.

Citat:
About the CO-production from ethanol, where did you see this explained?

I did not see it anywhere special I just used the wellknown fact for example from "Bilprovningen" that lower lambda than 1 gives more CO in the exhaust gases.

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InläggPostat: tor 07-06-14 08:04 
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So these guys got it all wrong?:


From:
http://www.turbofast.com.au/racefuel2.html

Citat:
This is a fuel with a large cooling effect provided by part of it evaporating after it has reached the combustion chamber and so tending to cool the valves, piston and so on.

Some may well get into the combustion chamber as liquid, due to the reduction in temperature of the induction system, pipes, carburetor, etc., and so extending the cooling effect, in the process counteracting the effect of the high internal temperature.

In view of this amount of fuel entering the chamber, with possibly some of it in liquid form, the ignition system must be beyond reproach since if the spark is weak the mass of fuel will just soak the plug and then at once ignition troubles arise affecting starting in particular.

Owing to the use of alcohol a higher compression ratio can be used with this fuel as compared with petrol, another consideration is the type of plug used which will be a hotter type than used before with petrol.


Citat:
I did not see it anywhere special I just used the wellknown fact for example from "Bilprovningen" that lower lambda than 1 gives more CO in the exhaust gases.


Can it have to doo with the lower performance of the catalyst at non-lambda 1...? The same result will come from lean mixture.
In reality all engine-out (before catalyst) emission with one exception (NOx at only slightly lean) are lower on lean running than on stoichometric.

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InläggPostat: tor 07-06-14 08:17 
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See also "Ethanol Fuel Cooling Allows 30% Fuel Efficiency Increase"
http://www.futurepundit.com/archives/003834.html

@Volvo-Berti: It is strange that you notice a faster rising of the engine temp on higher ethanol blends. This is oposite of my experiences with ethanol converted engines. But these are optimised for efficiency with higher compression ratio and/or more advanced ignition so the heat losses would be smaller. And an energy efficient engine produces less heat.

Could it be that your engine is running on a too lean fuel mixture and/or too late ignition which results in less efficiency and more heat losses?

/Aryan


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aryan skrev:
See also "Ethanol Fuel Cooling Allows 30% Fuel Efficiency Increase"
http://www.futurepundit.com/archives/003834.html

@Volvo-Berti: It is strange that you notice a faster rising of the engine temp on higher ethanol blends. This is oposite of my experiences with ethanol converted engines. But these are optimised for efficiency with higher compression ratio and/or more advanced ignition so the heat losses would be smaller. And an energy efficient engine produces less heat.

Could it be that your engine is running on a too lean fuel mixture and/or too late ignition which results in less efficiency and more heat losses?

/Aryan


Bear in mind that Volvo:s temperature gauges are the most faking instruments ever made..
Some idiot at Volvo cars thinks that a correct showing of the engine temperature will lead to too many complaints since stupid customers tend to complain if the needle is moving at all during use of the car.
(As a comparison, a Mercedes always shows the temperature actually measured, without any damping or "correction", the temperature indicated can therefore vary betwen thermostat temp and up to 100 deg C or even above in normal (queing and long time idle in hot days) operation, just as in reality)
This has (since the 760) led to a design where a very large temperauture span of the water will lead to a "normal" reading, a horizontal needle in the instrument panel.
I wouldn't count too much in from readings from equpiment like that.

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InläggPostat: tor 07-06-14 16:44 
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I can confirm this design of the engine thermometer of Volvo 700 and 900 series. Some months ago, i studied the circuitry of the instrument block of a '1985 Volvo 740.

There is a ridiculously complicated circuit behind the engine thermometer - four operational amplifiers, some transistors and so on.
Anyway, the instrument needle will begin rising at about 35-40 °C of engine temperature. At 65-75 °C it reaches mid position and remains there until about 110 °C when it rapidly continues rising. It reaches full scale at 120-125 °C. There is an adjustable resistor for setting the high temperature response of the instrument, but it does not affect the response at lower temperatures or the fixed mid position of the needle at "normal" temperatures.

According to loose rumors, there is said to be two different vendors of instrument blocks for Volvo 700 and 900: VDO and Yazaki. However, i have only encountered VDO instrument blocks.

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karlmb skrev:
So these guys got it all wrong?:


From:
http://www.turbofast.com.au/racefuel2.html

No they did not get it wrong but you did. On the second line in the link it is stated that they are talking of metanol (Methyl alcohol). The ratio of evaporation heat and burning of a stoichiometric mixture for methanol is 5,5% and in rich mixtures as they recommend for racing the ratio is closer to 7% which really is important.
-----

Citat:
Citat:
I did not see it anywhere special I just used the wellknown fact for example from "Bilprovningen" that lower lambda than 1 gives more CO in the exhaust gases.


Can it have to doo with the lower performance of the catalyst at non-lambda 1...? The same result will come from lean mixture.
In reality all engine-out (before catalyst) emission with one exception (NOx at only slightly lean) are lower on lean running than on stoichometric.

It has nothing to do with the catalyst it is all about what happens during burning of a rich mixture in the cylinder.

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aryan skrev:
See also "Ethanol Fuel Cooling Allows 30% Fuel Efficiency Increase"
http://www.futurepundit.com/archives/003834.html


------

The guy who wrote this article really got it all wrong when he explains the 30% power increase with the cooling effect alone.

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Citat:
No they did not get it wrong but you did. On the second line in the link it is stated that they are talking of metanol (Methyl alcohol). The ratio of evaporation heat and burning of a stoichiometric mixture for methanol is 5,5% and in rich mixtures as they recommend for racing the ratio is closer to 7% which really is important.


They also talk in general terms about alcohols, not only Methanol.
More is better ofcourse but it cannot lead to higher temps (than petrol) with a smaller amount of a similar cooling fuel (as ethanol is).


Citat:
It has nothing to do with the catalyst it is all about what happens during burning of a rich mixture in the cylinder.


???So the Bilprovningen results are from before the catalyst..?
Don't think so.
Any (almost) effect from wrong lambda is a result from what's takes place in the catalyst.
Since the reduction of all species measured by a simple gasanalysator as they use at bilprovningen (smog check) are converted to harmless gases by more than 90% in the catalyst, a change in engine-out emissions is hard to measure at all after a working catalyst.

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karlmb skrev:
Citat:
No they did not get it wrong but you did. On the second line in the link it is stated that they are talking of metanol (Methyl alcohol). The ratio of evaporation heat and burning of a stoichiometric mixture for methanol is 5,5% and in rich mixtures as they recommend for racing the ratio is closer to 7% which really is important.


They also talk in general terms about alcohols, not only Methanol.
More is better ofcourse but it cannot lead to higher temps (than petrol) with a smaller amount of a similar cooling fuel (as ethanol is).

If you look on their listing of properties of the components of racing fuels only methanol is mentioned. Regarding temperature in the exhaust the ignition timing and flame speed are probably more important than the difference in evaporation heat between ethanol and gasoline.

Citat:
Citat:
It has nothing to do with the catalyst it is all about what happens during burning of a rich mixture in the cylinder.


???So the Bilprovningen results are from before the catalyst..?
Don't think so.
Any (almost) effect from wrong lambda is a result from what's takes place in the catalyst.
Since the reduction of all species measured by a simple gasanalysator as they use at bilprovningen (smog check) are converted to harmless gases by more than 90% in the catalyst, a change in engine-out emissions is hard to measure at all after a working catalyst.

If an engine runs on a rich mixture consuming all the oxygen in the air there is nothing the catalyst can do about the carbon monoxide. I only mentioned "bilprovningen" as a wellknown source of data on CO in relation to the lambda values among us interested in cars. Otherwise there is more or less common "chemical" sense that CO rather than CO2 is formed in burning processes with oxygen deficiency. This is used in generator gas production "Gengas" for example.

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aryan skrev:
See also "Ethanol Fuel Cooling Allows 30% Fuel Efficiency Increase"
http://www.futurepundit.com/archives/003834.html


------

The guy who wrote this article really got it all wrong when he explains the 30% power increase with the cooling effect alone
.


Although I haven't read the whole article I saw that in the first lines he explainad that the gain in fuel-efficiency came from injecting ethanol at high loads in an engine otherwise fueled with petrol.

It even says so in the heading (rubrik): "boost conventional gasoline fuel enfine efficiency by xx%"

As I understand it, they claim that a "half-size" engine (in Sweden that would mean about 1000 cc) would perform as well as an engine twice 's size with (maybe among other things), injection of ethanol from a separate tank when needed...


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GL: I find this debate stupid, It is well known by race-engineers that you can use both methanol and ethanol to get more power out of your engine.

It is also well described by SAAB for instance that ethanol is a wonderful fuel which has shown even better possibilities than expected when it come to power outtake and in the end downsizing.
SAAB has shown on the possibility to in fact reduce the engine sixe by half. Are you really saying that this would have been possible with petrol too if only octanboosters where added?

It is also reported from tunig people that the exhaust temperetures are about 100 deg lower on ethanol than on petrol.

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