Is Ethanol "Losing Its Clout"?

[ionbeam]

...Fred.... huh? I thought by definition, C/R was the ratio of the volume of the combustion chamber at BDC compared to TDC.

It is correct that the static compression ratio is is a ratio of the cylinder volume measured with the piston at the bottom of the stroke (BDC) and the volume measured at the top of the stroke (TDC). The dynamic compression ratio looks how much content there is in the cylinder and what the final cylinder pressure is. Over filling the cylinder will cause a larger volume to be compressed into the static space, thereby causing a higher cylinder pressure. It is true that the cylinder swept volume hasn't changed, but the higher cylinder pressure acts like the swept volume was greater. There are multiple benefits of higher compression and having cylinders filled >100%, with a few significant drawbacks. If positive pressure isn't well designed as a system, parts will start to bend, develop cracks and holes resulting in sudden, dramatic power loss

Air is elastic, has mass, velocity and inertia when being inducted into an engine. A good engine design team can use these characteristics to tune an engine so that the cylinders can fill >100% with no other tricks. In fact it is possible to get up to 117% filling by exploiting the properties of air. Unfortunately, this makes for a very peaky engine. Positive pressure from super charging, even with the parasitic losses gives a great engine power curve. Turbocharging, even with the heating of the intake charge gives great engine power. Chilling the intake charge with NO2 along with an enrichment of oxygen gives great engine power but only in short bursts due to the massive consumption of NO2 depleting the supply and it is effective only with the throttle wide open.

 

[garyahouse]

But fuel mileage is the least of my concerns. I posted this link earlier, but I'll post again. It's the best article I've seen about while this national experiment has failed.https://news.yahoo.com/secret-dirty-cost-obamas-green-051200204.html

Interesting (though long) article. Some amazing stuff that I didn't know. Thanks for posting.

Gary

 

[Fred W]

Two questions:
1. Does anyone know if any metal parts of the fuel system (including the inside of the tank) have a coating on them that will inhibit the corrosive effects of Ethanol that remains stagnant? My Yamaha outboard boat motor (carbureted) does not and as such, ethanol is a known problem if the boat is not used regularly, and/or the carb bowls drained after each use.

This seems to be one those internet factoids that, after being repeated often enough is taken as being a being true, but... What exactly about ethanol is so corrosive to metal? I would suggest, nothing. Ethanol does negatively effect rubber and certain plastic parts, but metal?

The main reason that carbs get all gummed up after storage is the fuel evaporates and leaves behind a hard varnish that plugs up jets and such. But this always happened with non-oxygenated fuels too. I suppose that the ethanol laden fuel sitting in the float bowls for a long time would effect the gaskets and seals, but that would be true if the bike was just sitting or being used and fresh ethanol was constantly being introduced.

The idea that ethanol is hygroscopic and therefore absorbed H2O will corrode the metal fuel tank isn't quite right either. Consider that any water that is absorbed in the fuel would have been in the fuel tank anyway (the alcohol didn't make it come in there) but if the fuel was straight gas with no alcohol the water would be in a separate state. And we know that water is highly corrosive to metals. Having alcohol in the fuel actually allows the water present to be absorbed and then burned (vaporized) along with the fuel. Yeah that doesn't help get rid of it when the tank is being stored, but neither does straight gas.

2. "...Of course since naturally aspirated engines do not have variable compression ratios (unlike turbo or super charged engines)..."
Fred.... huh? I thought by definition, C/R was the ratio of the volume of the combustion chamber at BDC compared to TDC.

Yup, that formula is correct... for a normally aspirated engine. Forced induction (turbo or blower) jams several PSI of air (and fuel) into the cylinder during the intake stroke, thereby increasing the effective compression ratio. IOW, the intake is already pre-compressed, so the total compression ratio is greater.

Modern turbochargers are really a thing of technical beauty and elegance. Yes, just strapping an intake compressor onto an engine not designed for the increased power it can generate can easily cause problems. But when a powerplant has been designed for the added torque of a high compression turbo blower it is the best way to achieve power when needed and still maintain reasonable economy when the power is not needed.

As I've mentioned in the past, I have been rather a big fan of SAAB autos for quite some time. Their design engineers were some of the first to truly embrace turbocharged forced induction as a design tenant, and they had pretty much perfected them before their recent demise. It was too bad that GM purchased a controlling share and then proceeded to run the company into the ground with traditional bad American business management practices. But the good news is that the marque has been resurrected and will live on in Trolhatten, Sweden. Whether we ever see any new SAABs here in the USA again is up in the air right now.

The limiting factor on how high you can pre-compress the intake air (called the boost) for most modern turbo or supercharged engines is the octane value of the fuel. If the boost is too high it will cause detonation and the engine will fragment. Inter-coolers have become commonplace on turbocharged cars and trucks to offset the heat generated during the pre-compression and reduce the likelihood of detonation. They are basically just an air to air heat exchanger (radiator) that the intake passes through after the blower compresses it but before induction.

Even with engines that have dimensionally low compression cylinders, any decent turbo can create too much boost. How much is too much is critical to engine health and entirely dependent on the fuel octane in the tank. Turbo engines generally have a knock sensor to sense the onset of detonation and will automatically reduce the boost levels when knocking is sensed. That allows you to run lower grades of fuel without destroying your engine, albeit at lower power levels due to the reduced boost.

There are some new design ideas that would use direct ethanol injection, substituting it for a fraction of the regular gasoline fuel injection, just during high boost situations as a means to allow even higher boost levels without knocking or detonation. Of course just running a higher percentage ethanol fuel would have the same effect but with negative consequences on fuel economy when you were not on high boost.

 

[hppants]

Fred: (Respectfully)

I've worked on quite a few carbed outboard motors and motorcycles. I've personally seen the difference between a carb body/bowl that has been treated with an anti-corrosion coating (Most Mercury Opti-max motors pre-2008-ish for example) and one that has not (my Yami-C90 triple, for example). There is a visible coating that can be observed and felt. I've also seen my share of varnish in all kinds of carbs. Perhaps it's some kind of amazing coincidence, but carbs I've worked on running ethanol with the coating are not simply not corroded. Varished? Sure, but not corroded like carbs without the coating. Of course, marine engines by nature may be more susceptible to water related issues. But alcohol - even a 10% dilution - is hydroscopic, and water is corrosive on untreated metals. There's no mystery in that.

Secondly, much thanks for your comments on turbochargers. Obviously you are well read on the subject. However, I still fail to understand how increasing the pressure on the intake side of the engine somehow changes the volume of the combustion chamber? Of course the pistons don't mysteriously move closer to the cylinder head when the boost is cranked up. Perhaps I'm not familiar with the term effective compression ratio, but regardless, I think that term is confusing and mis-leading. Increasing the intake pressure on the motor makes the air/fuel mixture more dense, more efficient, and gives it the potential to make more potent explosions and thusly, more power. But it doesn't change the compression ratio.

 

[huron52]

Whether or not you like this ethanol added to gasoline doesn't really matter. It is the way of the world. There is only so much down there and when it's done it's done. As to how long it will last maybe anyone's guess.

If cost a consideration we wouldn't have electricity made from Solar or Wind! We would create electricity by coal.

I remember when unleaded gasoline came out and they dropped premium gasoline all together for a while.At that time I remember buying a lead adidtive to the gasoline I put in my boat. After a while I just gave up doing that. Did the engine die? no. My boat mechanic couldn't believe that the motor never had a wrench put to it, 30 years later!

Personal findings with ethanol and small motors. I only use my gasoline powered lawn mower to cut up leaves in the fall. 2 gallons (9 liters) last me two years. Last years ethanol gasoline fired up my mower just fine this year. Maybe it's a new plug that makes the differenece? no! the plug is about 5 years old. Maybe I am doing something right. My generator has ethanol gasoline in it . What I do there is a run it dry everytime I shut it down so there is very little if any in the float bowl.

 

[ionbeam]

Dunno if it will help, but read this previous post.

 

[FJReady]

Oh my effing God. I can believe the intestinal fortitude of you nuts guys. 4 pages?? PMS must be settling in big time. Otherwise you'd be out pouring whatever came out of the pump at some gas station somewhere and enjoy every minute of burning it. This sounds like a reading of the call for white papers at some petroleum engineers 'get a life' convention in Tulsa. Nothing personal, Tulsa.

 

[Redfish Hunter]

Wow. Zilla actually started something interesting and intellectually stimulating.

Ethanol is an excellent solvent. When it hit the ONLY fuel dock in Leeville, Louisiana it was a disaster. The ethanol "cleaned" the storage tank at the fuel dock. That suspended gunk was then pumped into all the boats that bought their fuel from there. Then, it cleaned the individual tanks in those boats. This garbage then plugged all the fuel filters on all of those outboard motors. EVERY Yamaha powered charter boat in Leeville was dead in the water due to plugged fuel filters. We collectively bought every Yamaha fuel filter available and still could not keep our engines running. That dock has since sold nothing but "pure" gasoline.

I have seen the white powdery corrosion inside Yamaha marine fuel systems after ethanol use. I cannot argue with Fred's logic, but I know there is more corrosion now than we had before.

The compression ratio does not change with turbocharging. The combustion chamber pressure goes up with turbocharging. hppants you are pretty knowledgeable concerning hot rod engines, you do know that for a turbocharged engine you want a lower compression ratio? My Duramax diesel is only running a 16.8:1 compression ratio. This is possible due to the variable vane turbo boosting combustion chamber pressure. This 403 c.i.d. V-8 has 25 psi of positive pressure on the intake side at 3100 rpm. Compare that to the distinctive intake honk of the old Quadrajet carbs we ran in our younger days.

Edit: Many of you said that your FJRs were not affected (noticeably) by the E-10 fuel. I have no theories as to why this is so but E-10 does affect my ST1300 more than it affects Dad's FJR. Since there are so many variables involved from one tank to the next it is often impossible to accurately say what caused the changes in MPG. However, when the two bikes are fueled up together over and over on a trip it is easy to tell when one is suddenly using more fuel than the other.

 

[yamafitter]

Chilling the intake charge with NO2 along with an enrichment of oxygen gives great engine power but only in short bursts due to the massive consumption of NO2 depleting the supply and it is effective only with the throttle wide open.

Most of the power gains from using Nitrous Oxide (N2O not NO2) comes from the chemical breakdown of the gas forming free oxygen atoms to aid combustion. This allows the introduction of more fuel to be injected into the combustion chamber that can be completed ignited. The power gains are therefore a product of the extra fuel being burned by the additional oxygen being supplied by the breakdown of the N2O. Early automotive applications use solenoid valves to control the injection at only full throttle due to the risk of an extremely lean condition at partial throttle due to disrupted fuel flow.

The newest systems have stage valving which allows better control of the N2O injection and increased power gains over a range of throttle positions rather than the old all or nothing system. There may also be some small gains from chilling the air/fuel mix increasing the mixture density but most of the power gain comes from increasing the amount of oxygen available to support the larger fuel charge.

Nitrous Oxide link

 

[ionbeam]

...Nitrous Oxide (N2O not NO2)...

I normally know the difference between nitrogen dioxide and nitrous oxide, I don't know why I typed NO2 this time. Several of my friends run N2O in their cars and it proves to be a PITA almost every time they need it to work for a full day at the track. A few years ago one guy at New England Dragway had a tank heater stick on and didn't know it, the resulting explosion was like a box of dynamite going off. Among the successful power adders N2O is at the bottom of the list for user friendliness.

 

[RossKean]

N2O is at the bottom of the list for user friendliness.

Sounds like a bit of an adrenaline rush!

Nitromethane is a little friendlier as a means of getting a bit of additional combustion potential into the cylinders. My experience with high-alcohol (methanol) and nitromethane (up to 30%) is confined to model airplane engines. Those little motors can make a bunch of power but fuel consumption is a little high!

This is almost as much fun as an oil thread!

 

[FJR Flyer]

The compression ratio does not change with turbocharging. The combustion chamber pressure goes up with turbocharging. hppants you are pretty knowledgeable concerning hot rod engines, you do know that for a turbocharged engine you want a lower compression ratio? My Duramax diesel is only running a 16.8:1 compression ratio. This is possible due to the variable vane turbo boosting combustion chamber pressure. This 403 c.i.d. V-8 has 25 psi of positive pressure on the intake side at 3100 rpm. Compare that to the distinctive intake honk of the old Quadrajet carbs we ran in our younger days.

First off, I hate that ethanol is shoved down our throats (or into our tanks). I use Startron, Stabil, Techron, etc. Hasn't really affected the FJR, but the FJ doesn't like it.

Anyway, wrt chamber pressure, I remember while growing up, my best friend's dad built several street rods. All of them were blown. And he always used pistons with low compression ratios to allow the blower to do its business. FWIW.

 

[hppants]

Looking back over this thread - it appears that my crappy day yesterday bled through in my writing. I am kind of a stickler for terminology - it's part of the Anal Package I signed up for at birth. Still, I get the principles and I didn't mean to pick a fight. Apologies all around.

It's the weather. We gulf coasterners get really cranky when the temperature dips below 50.

 

[Fred W]

But alcohol - even a 10% dilution - is hydroscopic, and water is corrosive on untreated metals. There's no mystery in that.

Actually, also being a stickler for terminology, alcohol is hygroscopic.

While water is highly corrosive to certain metals, once absorbed by the alcohol it is no longer water. The oxygen in alcohol is somewhat corrosive (can cause some oxidation), more so in greater concentrations of alcohol, and is more corrosive to metals than gasoline, but not nearly as corrosive as as the water that it absorbed which would have remained separated from the gasoline fuel if it had no alcohol.

It is a matter of degrees of corrosiveness. Would you rather have pure gas and highly corrosive water in the tank? Or have the water molecules absorbed (and diluted) by the alcohol which is mildly corrosive. It's why they used to sell dry gas in the winter months. Water will find its way into your tank. The alcohol provides a means to absorb those water molecules and get rid of them through combustion.

edit - Alcohol is a solvent. Gasoline is also a solvent. So is water. They just will dissolve different materials.

However, I still fail to understand how increasing the pressure on the intake side of the engine somehow changes the volume of the combustion chamber?

Of course, forced induction doesn't change those dimensions. And I do understand that the term "compression ratio" has historically been used as a ratio of those dimensions. But the reason that we even care about those dimensions is because they affect the pressure at TDC.

What forced induction does is to increase the maximum pressure in the combustion chamber at TDC as compared to ambient atmospheric pressure, which is really the entire point of having a compression stroke to begin with. More pressure at TDC = more potential power during the combustion stroke.

So, a definition of "effective compression ratio" would be the ratio of the pressure at TDC vs. atmospheric pressure. Or restated, a ratio of the effective compression.

FWIW there have been engines designed that do change the dimensional compression ratio. SAAB engineered an engine that had a split block that allowed it to actually move the cylinder and head in reference to the crankshaft to vary those dimensions. Of course that design project was killed by GM when it took over control of SAAB back at the turn of the century. Probably something to do with the "Not Invented Here" syndrome.

 

[C&C]

One other denominator is the fuel system itself; most/more of the ethanol problems occur with open/vented systems, i.e. carburetored engines, where water (as in water vapor) can more easily enter the system. Closed systems, i.e. fuel injected engines with evaporative control circuits are less prone. A lot less prone in the case of water intrusion though there is still the drying effect on certain rubber/plastic components, and here lies the rub with going to E-15 (and the already available) E-85 (unless the engine has been designed to use these).

 

[bucky]

The coop in snohomish washington sells only ethanol free gas. However it is about 50 cents a gallon more. I run that in all my yard equipment, generator, etc. And in the motorcycles unless out of town and need to refuel. And in the fall, I start adding seafoam to the tank on fill-up so that the final tankful of gas over the winter has both seafoam and ethanol free gas in it.

 

[RichDoyle]

For me there's never been a "final time over winter" Maybe a couple of weeks here and there, but that's been it. Lived in Eastern Idaho, Colorado foothills, and Western Washington most of my riding life and never had reason to park it "for the winter".

 

[art miller]

Hell's bells, I've read thru all these pages and I think Old Guy posted the most relavent response to the topic. Much of the technical info was interesting but bottom line, I am not a believer in the ethanol hype. In my opinion much of the green movement is based on phony ideas that have very little real science to prove their claims. Let's get on with using natural gas more effectively as well as nuclear. There is adequate oil in the ground to provide gasoline for small engines and vehicles that cannot accomodate compressed fuel tanks or large battery packs.

 

[TheRepairMan]

Wow! I was sure this thread was going to at least have one FJR powered chain saw in it. I'm pretty disappointed in all of you.

Now, this guy has some potential problems!

-R

 

[RaYzerman19]

As I understand it from my too-much-time spent researching E10 problems....... the truths are not always there. Example, seems I can't believe the 11-14% fuel mileage thing now. I've always wanted to prove for myself that mileage difference between non-E and E fuel, but non-E fuel is not available to me. I kinda agree with Geezer that effects vs. percentages of chemicals is not linear, but I'll add that our thinking is about our small part where all the conditions aren't available to us (region, climate, mountains, plains, dynos), and our high output engines may be more efficient that say car engines, oh so many different car engines out there too.. I hate politics in general that cloud the issues and keep us from getting what is 'right', whatever that is. Everyone has an opinion, but do we have all the facts or did we test our fuel mileage under the same conditions (no)...... this is like another oil thread, but hey, it's obvious there are problems with E fuel or all this debate across the country (countries) wouldn't be happening, nor would we be having so much fun on this thread. I recently read a large survey was done across America about E15, and one conclusion was 93% of the population hasn't got a clue what E15 is or what it does. Makes it difficult to have the powers that be understand our concerns. Lets face it, cars trucks buses eat more fuel than us few bikes, our voice will be small. Diesel is huge and doesn't even count in this debate, different animal. Try putting ethanol in diesel fuel..... ooops, bye bye engine.

On the issue of water, my understanding is ethanol reaches it's saturation point with water at 4.5%, then there's the phase separation of the ethanol, the water and the gasoline. Ethanol is corrosive in the sense that it tries to dissolve the natural film of gum/varnish that line fuel tanks, but it won't dissolve it. In an extreme example, liken it to trying to remove decal glue residue with a harsh solvent like toluene, you get lumpy stuff that dries back up before you can get it off, plus it eats your paint..... so you use naptha, much slower and better at actually dissolving it, won't hurt much...... Seafoam, works same way with fuel system crud, add harsher solvents and you get Techron. Isopropanol is far more effective at absorbing water than etha- or metha- alcohols.... that's in Seafoam and Techron too. Huge industry in expensive little fuel fixer additives..... Anyway all that just gleaned from what I've been able to read and dig into myself...... not a chemical whiz..... I'd like to see lab reports more than listen to politics, speculation and opinion..... hard to come by if at all.

As mentioned by Redfish, all that crap with Yamaha outboards.......... Yamaha recommended 10 micron fuel filters (previous were 30, I think) to catch all the crud being stirred up by E fuel. Part of that was it was not only the gum/varnishes inside the tanks, but it ate the fiberglass tanks too. Corrosive is the wrong word for that IMHO.... I think of corrosion as attacking rubber and oxidizing metals kind of stuff, just me.

Anyway, discussion is always good...... again, just give me a choice of non-E.... I will test some theories for myself with it.

So, nobody commented on what the gunk build-up on throttle bodies and intake valves stems is (that causes them to stick).......... ideas?