Etanol.nu

Forum för föreningen etanol.nu
Aktuellt datum och tid: tor 18-07-19 16:38

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InläggPostat: mån 14-06-02 13:02 
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Blev medlem: fre 14-05-09 07:33
Inlägg: 47
Inte en ny studie som ni ser i trådtiteln, en del av er kanske redan har läst den (å andra sidan, inte den enklaste att hitta) men väldigt informativ och ett klart steg upp från "jag hörde" eller "etanol borde... ".

Tänker bara citera några av de intressantare delarna eftersom det är så mycket, men ni finner länkar till samtliga tester och resultat här nere:
http://www.mda.state.mn.us/renewable/et ... sults.aspx
Citat:
E20 Test Results

Results of drivability and compatibility tests by the State of Minnesota have found that motor vehicles operating on a 20-percent blend of ethanol fuel will perform as well as those running on 10-percent ethanol or gasoline. The tests also found that using the higher E20 ethanol blends did not cause significant problems for a wide range of materials, including metals, plastics, rubbers and fuel pumps used in vehicle fuel systems.

The study used nationally recognized standards and protocols to ensure research quality. It was conducted at Minnesota State University Mankato and the University of Minnesota, with cooperation from the State of Minnesota, including the Minnesota Departments of Agriculture and the Pollution Control agency, and the Renewable Fuels Association. The study included input from fuel refiners, automakers and small-engine manufactures, and funding support from the Minnesota Corn Growers Association and the Council of Great Lakes Governors.


Executive Summary (PDF: 48 KB / 6 pages)
Drivability Study (PDF: 615 KB / 63 pages)
An Examination of Fuel Pumps and Sending Units During a 4000 Hour Endurance Test in E20 (PDF: 1.08 MB / 24 pages)
Effects of E20 on Automotive Fuel Pumps and Sending Units (PDF: 500 KB / 13 pages)
Effects of E20 on Plastics used in Automotive Fuel System Components (PDF: 241 KB / 22 pages)
Effects of E20 on Metals used in Automotive Fuel System Components (PDF: 299 KB / 16 pages)
Effects of E20 on Elastomers used in Automotive Fuel System Components (PDF: 634 KB / 35 pages)
Ethanol E20 Durability Study (PDF: 960 KB / 24 pages)

Utdraget från metodik-delen:
Citat:
The fuels represent both commercially acceptable fuels, but also represent the least desirable fuel properties for compatibility with fuel system components.
These fuel mixtures are selected to initiate compatibility interactions and were utilized throughout the various test protocols. The three test fuels
included:
• Surrogate gasoline (C) – ASTM fuel C, 50/50 toluene, isooctane mixture (500ml toluene, 500ml
iso-octane)
• E10 Fuel [C(E10)A] – 90 percent Fuel C + 10 percent aggressive ethanol(450ml toluene, 450ml
iso-octane, 100ml aggressive ethanol)

• E20 Fuel [C(E20)A] – 80 percent Fuel C + 20 percent aggressive ethanol (400ml toluene, 400ml iso-octane, 200ml aggressive ethanol)
Aggressive Ethanol – synthetic ethanol 816.00g, de-ionized water 8.103g, sodium chloride 0.004g, sulfuric acid 0.021g, glacial acetic acid 0.061g.


Med andra ord, the baddest stuff de kunde blanda ihop och ändå vara "inom specifikation". Har man följt svensk media i år vet man ungefär vad man har att förvänta sig, eller? :wink:

Fuel Pump och Sending Units endurance studien är intressant:
Citat:
CONCLUSIONS
This study tested and compared the effects of E20 to that of E10 and gasoline on eight fuel pump models and three sending unit models in three different fuels for a total of 24 fuel pumps and 9 sending units.
Both the pumps and sending units were subjected to a 4000-hour dynamic endurance test.

Throughout the test, the cleansing effect of the ethanol fuels was very apparent.
The pumps, sending units, and test fixtures immersed in gasoline were coated with a grayish-black residue while the same items in E10 or E20 displayed little to no residue.
It was noticed that some pumps tested in E20 had light surface corrosion, but not to the extent to
affect their function.


In terms of performance, fuel flow and current draw, four pumps either completely failed or could not develop sufficient pressure at the end of the study.
Two of these were in gasoline and two were in E10.
No clear trends in pump performance between any of the fuels were found.
A clear trend in commutator wear was found between gasoline, E10, and E20. The commutators of
several of the pumps tested in gasoline wore substantially
more than in either ethanol fuel.
This wear was significant enough that if the test would have continued longer, several of the pumps tested in gasoline would have stopped because their commutator would have worn through.

Overall, E20 did not cause any greater negative effects than gasoline or E10 on the fuel pumps tested.

By the end of the study all of the sending units tested had failed, regardless of which fuel they were in. All exhibited excessive resistance changes along with regions of signal drop out (opens). Visual differences were noted between the sending units tested in E10 and E20 when compared to gasoline, but these did not affect the functionality.
No significant differences in performance or in failure were noted between the sending units in any of the three fuels.


Lite bilder från Fuel Pump och Sending Units endurance test studien:
BildBild
BildBild
Bild

Från plast-studien:
Citat:
ABSTRACT
The focus of this study was to compare the effects of E20 versus E10 and gasoline on plastic materials found in automotive and small engine fuel system components.
Plastic samples were prepared using SAE and ASTM standards and exposed to blends of ASTM
Fuel C; 90% Fuel C and 10% aggressive ethanol (E10); and 80% Fuel C with 20% aggressive ethanol (E20) at an elevated temperature of 55 °C for 3024 hours.
The fuel was changed in weekly intervals for the 18-week study.

CONCLUSIONS
Using industry-recognized standards, this study tested eight different plastics found in automotive and small engine fuel systems to determine if they performed significantly different when immersed in
Fuel C, E10, or E20.

The study found that four of the materials, PA 6, PA 66, PET, and PEI, were compatible with the three fuels.
The other four materials, ABS, PUR, PVC, and PBT, were affected by all three fuels to varying degrees.

The ABS specimens failed after less than one week of immersion in all three fuels. The specimens turned to a jelly-like mass in the bottom of the jars.
This material was not compatible with any of the fuels.
Finally, no automotive or small engine fuel system applications of ABS could be located, quite possibly due to its incompatibility with fuel.

PVC (flexible version) demonstrated significant changes in mass and volume in all three fuels but to a higher degree in ethanol fuels. The PBT data also showed significant changes in impact resistance in all three fuels but to a greater extent in the ethanol blends. PUR (55D-90A durometer hardness)
was deemed incompatible with both E10 and E20 due to cracking and changes in mass, volume, tensile strength, and elongation.
In each case with PVC, PUR, and PBT both E10 and E20 caused large enough changes to raise a concern. Because of this, these materials would be a poor choice for use with either E10 or E20. Finally, no fuel system components made of either PUR or PVC could be located.

Different degrees of discoloration were observed in many of the other test samples, slight yellowing of plastics occurred on a few samples with E20 causing more yellowing. Samples were marked with an engraver for identification purposes.
All can still be easily read with the exception of the PUR sample immersed in E20.
Discoloration does not mean a failure in an automotive fuel system component.


Metall-studien:
Citat:
ABSTRACT
The focus of this study was to compare the effects ofE20 versus E10 and gasoline on metal materials found in automotive, marine, and small engine fuel system components. Metal samples were prepared using SAE and ASTM standards and exposed to blends of Fuel C; Fuel C and 10% aggressive ethanol; and Fuel C with 20% aggressive ethanol at an elevated temperature of 45°C for 2016 hours.
The fuel was changed in weekly intervals with photo images and mass loss/ gain data recorded at the 1st, 3rd, 6th, and 12th week.

CONCLUSIONS
This study tested and compared the effects of E20 to that of E10 and Fuel C on 19 different metals used in automotive, marine, and small engine fuel systems and fuel dispensing equipment. Eighteen of the nineteen metals were found to be compatible. One metal, Zamak 5, exhibited unacceptable levels of corrosion in both E10 and E20.
It was deemed unacceptable in both fuels because of pitting and the formation of loose corrosion by-products that could clog fuel system components. Zamak 5 also exhibited an excessive mass loss when exposed to E20. Again, it should be noted that the Zamak 5 samples used in this study were not plated, which could be the reason that the corrosion problems found in this study with E10 are not seen on automobiles currently being used with E10.
Different degrees of discoloration were observed in many of the other materials. While many of the materials yielded higher discoloration as the ethanol concentration increased, they did not show signs of pitting, loose corrosion by-products in the test fluid, or have a mass loss that exceeded a rate that would cause a failure within a 20-year life cycle.


Så sammanfattat, om era fordon inte är byggda med bränsle-system av Zamak 5, Magnesium och ABS/PVC/PUR-plast så borde det gå rätt bra, kanske rentav bättre än med bensin.

Vad är Zamak 5? "a base metal of zinc and alloying elements of aluminium, magnesium, and copper."
Vart används den i bilar? "an alloy used in some carburetors", dvs inte aktuellt i bilar med fuel injection. Men även från studien:
Citat:
It should be noted that Zamak 5 is often plated to make it more corrosion resistant for fuel applications and the samples used in this study were not plated.


Citat:
Magnesium AZ91D is a die casting alloy that is commonly used in carburetors and diaphragm pumps
blev uppkäkat av samtliga bränslen, men inte snabbt nog för en 20-års livscykel.

Hoppas det här är informativt.


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InläggPostat: mån 14-06-02 15:04 
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Blev medlem: lör 06-12-23 09:31
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Hoppas det här är informativt.


Verkligen, tack! Skule vara intressant att se hur en pumpar som enbart körs i E85 skulle sett ut, kanske lika bra som med E20?

_________________
Komplettera gärna data om dit piggybacksystem här: http://www.editgrid.com/user/aryan/E85_piggyback_system och här viewtopic.php?f=10&t=6352


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InläggPostat: tis 14-06-03 14:58 
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Blev medlem: fre 14-05-09 07:33
Inlägg: 47
Kanske, men det är bra mycket större skillnad i andelen etanol jämfört med E10 till E20 (eller E0 till E20 för den delen). Etanolens kemiska egenskaper blir tydligare (inte direkt oväntat).

Från det jag har läst så blir det ungefär som jämförelsen i studien här, renare men påverkan på de plaster och metaller som är "svaga" för etanol blir större/tydligare. Sen om det faktiskt påverkar delens funktion är inte sagt (se studie nedanför för ett exempel).

Tyvärr är det bristfälligt med utförliga studier (eller studier alls) när det kommer till olika etanolblandningar (speciellt kontra bensin).

Här finns en studie som specifikt tittar på aluminium (etanol > aluminium, som vi vet) delar till en motorcykel med E20, E85 och E100 (motorcyklar är vanligtvis inte rekommenderade att tankas med höga koncentrationer etanol eftersom dom inte byggs lika etanol-vänliga som bensinbilar):
http://www.material.chula.ac.th/Journal ... 0WIROT.pdf
Citat:

The goal of this study is to assess the corrosion value of two cast aluminum parts in a motorcycle, which are cylinder head and carburetor.
Sample specimens were prepared from the two aluminum parts, then immersed in three different ethanol fuel blends, containing ethanol at 20 (E20), 85 (E85), and 100 (E100) vol.%, testing at two different temperature levels (room and 50°C). Based on the immersion test results, corrosion was observed on the surface of the specimens, and determined to be a pitting corrosion type. The weight loss and depth of pit were measured after 1, 2 , and 4 weeks.
From the measurement results, higher weight loss and deeper pit depth values were found in the case of fuel blends with a higher ethanol content (E100> E85> E20) and at a higher temperature level (50°C>25°C).
As time progressed, the corrosion also continued on (i.e., higher weight loss and deep pit depth), but at a slower rate (i.e., lower weight loss and pit depth occurred during a later week).
This slower rate may have been caused by the formation of oxide film at the surface of the specimen
s, which acts as a protective film and prevent further corrosion into the material.
Nonetheless, the weight loss and pit depth values on both aluminum parts under the selected testing
conditions used in this study were still within an acceptable range for the utilization of these parts with ethanol fuel blends in a motorcycle.


CONCLUSIONS
Finally, the corrosion appeared to be more severed in Al320.0 (cylinder head) than in Al383.1 (carburetor) under the same testing condition. Nevertheless, based on the weight loss and depth of pit values from both cast aluminum parts under the selected testing conditions used in this study , it can be concluded that the pitting corrosion that occurred on these parts were still within an acceptable range; and thus, these parts should be able to be safely used with ethanol fuel blends or even pure ethanol (E100).


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InläggPostat: tis 14-06-03 15:33 
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Jag har kört E85 i motorer med förgasare av aluminium/zink? legeringar mässing spridare och alumiumtoppar och har inte heller sett någon påverkan som är större/värre än med bensin.

_________________
Komplettera gärna data om dit piggybacksystem här: http://www.editgrid.com/user/aryan/E85_piggyback_system och här viewtopic.php?f=10&t=6352


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InläggPostat: ons 14-06-04 12:00 
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Blev medlem: fre 14-05-09 07:33
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Ja, det är lite vad studien pekade på. Det sker en reaktion (inte oväntat, basic kemi) men det betyder inte att det går fort (nog).

1) Dessa experiment använder "aggressiv" blandning av etanol (med tillsatser som angivet ovan) och gärna i högre temperaturer (speciellt över 60 grader så börjar aluminium brytas ner fortare), men som studien också visar så avtar korrosionstakten med tiden när det byggs upp skyddande legeringar (inte så insatt i hur det fungerar med mässing eller bly jämfört med aluminium rent kemiskt).
Den aggressiva blandningen är till för att simulera Worst-Case som kan uppstå vid en pumpstation om någon tankbil t.ex. inte rengjort ordentligt så att föroreningar tillförs tanken. Tuffare etanol och högre

2) I riktiga fordonskomponenter som använder dessa utsatta metaller så brukar det finnas något sorts skydd inbyggt (den kemiska reaktionen är inte okänd för fordonstillverkare!). Det brukar skilja sig väldigt lite mellan komponenterna flexifuel bil och vanlig bil

3) Ibland tillsätts även korrosionsinhibitor till bränslet i sig (bensin som etanol-bränsle), beroende på land, lagkrav och bränsleproducentens egen bedömning (om det nu inte finns något lagkrav).

4) Vatteninnehållet kan påverka bränslets egenskaper. Lite mer vatten (0,5%>) hjälper tydligen till att skydda aluminium jämfört mot väldigt torr etanol (<0,1% vatten)! Detta varierar från pumpstation till pumpstation.

Så även om det rent kemiskt sker en nedbrytning så betyder det inte att det sker i en takt som är märkbar vid normalt bruk (om det är när 20+ år har passerat så är det inte många som lär märka det), men det kan variera från fall till fall (måndagsexemplar etc). Som du säger är det inte omöjligt för bensin att också påverka, och delar går som bekant sönder även till "vanliga" bilar oavsett bränsleval (vilket gör vetenskapliga studier svårt).

Skadorna som etanol skulle orsaka verkar därmed inte vara något som skulle ha någon *praktisk* effekt i de flesta fall, kan vi konstatera (men sen finns det alltid undantag).


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