Ok since this is about Ethanol, i thought i'd ask instead of creating a new thread, What do they do differently to the engine to make it run on E85, is it something mechanically or does it deal with the computer in the vehicle and its ability to determine what is being sprayed into the engine or maybe a combination of both?

 

Computer and sensors. The computer detects how much ethanol is in the gas and adjusts to compensate. Most FFV's simply inject more fuel; they don't even adjust ignition timing. It's like the auto manufacturers don't even try to optimize mileage on E85. Why would they? There's no incentive for them to do so AFAIK.

As I'm sure most of you have already read, FFV's are a compromise solution. They have engines that are optimized for gasoline, not E85. They don't fully utilize the favorable aspects of the fuel, namely the octane rating, and thus lose mileage when burning E85.

I'm still waiting to see an E85 optimized engine built by a major auto manufacturer. I have one sitting in my garage, but I built that so it doesn't count.

It's the whole chicken and the egg thing. Current FFV's lose some mileage on E85. The potential is there in the fuel for good mileage, but in order to use it the engine cannot run gasoline. For auto manufacturers to produce E85 optimized engines, they must be economical. For them to be economical, there has to be enough pumps available. For pumps to be available there must be demand. For there to be demand, it must be cost effective for the customer. And so we're back around to: FFV's lose some mileage on E85.

 

Since ethanol has higher octane potential, the engines would have to be built specifically to use this octane. The FF engines have a wider map that allows different useage of the fuel and spark curve maps. It's not so much more fuel, because based on the higher octane, these engines would really suffer in the mileage department. The problem is the map is not written specifically for E85 but both fuels. There are upper and lower limits, along with meeting FED regs on fuel econmy. The reason E85 does not get the mileage is there is less BTU's per given part as compared to gasoline. Hence the reason you can't dump E85 into a non FF vehicle. Not only would it not run good, but the mileage if you can keep it running would be terrible.

 

Just to let everyone know, the fuel lines,injectors,pump,all parts that come in contact with alcohol is different! Alcohol will deteriorate metal parts. The computer system is also different.

 

Actually, it is simply more fuel. I'll say this once. The octane has absolutely nothing to do with fuel delivery requirements! It's all about the air to fuel ratio, and how it relates to the characteristics of the fuel, namely the stoichiometric ratio, lean burn limit, and rich burn limit. Ethanol requires that more fuel be injected than gasoline because it's stoichiometric ratio is lower. That's the only reason. It does have a wider burn window there, with more tolerance of rich and lean conditions beyond stoichiometric than gasoline, but to run right it needs to be run with a richer air to fuel ratio than gasoline.

I'll also say something else once. Energy content (BTU) is not the only factor in determining miles per gallon! We need to look at thermal efficiency. Or more simply, how much of that energy is converted into motion in the form of pushing the vehicle forward. This is directly related to the compression ratio of the engine. The higher the compression ratio, the more of the available BTU's in the fuel will be converted by the engine into mechanical energy. That's a fancy way of saying when you raise the compression ratio the MPG goes up. Since ethanol has a higher octane rating, you reach a point when raising the compression ratio where the MPG of a ethanol optimized engine meets or exceeds that of it's gasoline burning counterpart. In doing this you also lose the ability to safely run gasoline. This is why I said that all current FFV's are a compromise solution.

I have dumped E85 into a non-FFV. It was a 1992 Explorer, with the 4.0L V6. But I changed the fuel injectors to larger ones to compensate. Mileage went down from 15mpg to 13mpg. Drivability and power remained excellent, with power improving slightly.

But I do agree that dumping E85 into an unmodified non-FFV wouldn't turn out too well.

Ranger, look up the part numbers for the 2006 FFV F150's fuel pump, injectors, etc, then look up the ones for the 2006 regular F150's fuel pump, injectors, etc. I think you'll be surprised.

 

On an 06 yes. Look up other years.

 

Say all you want once, but you are not quite that correct, btu outputs has a lot to do fuel econmy and output. By raising the compression ratio you make full use of the octane. Higher octane runs cooler due to the differences in vaporization. Higher compression will yield more power. I agree!
In your imfamous words I'll say this only once I know the programming of the ECU's and how they map with EPA regs and FF. Lets just say we here in house have the routines based on company fuel and ignition profies for multiple fuels.
If any differences in the injectors it's due more to the construction and materials use. Reason being E85 since it contains the majority of alcohol is more caustice or corrosive to certain parts.

Quoted from my source!
"The fuel tank, fuel lines, fuel injectors, computer system and antisiphon device have been modified slightly. Alcohol fuels can be more corrosive than gasoline; therefore; fuel system parts have been upgraded to be ethanol compatible."

After looking at the Ford part manual it looks 2005 and 2006 now have the injectors as stated as new style. So one can conclude that at one time there may have been a difference in part numbers but has been modified for FF under 1 part number due to the use of alcohol.

Now if you are converting over then yes a different injector would most likely have to be used since the ECU map may not be able to handle the increased pulse time needed. So a higher violume injector would compensate for the difference in pulse time.

The fuel sensor in the fuel tank will determine the percentage of alcohol. The output is in pulse width and frequency. A frequency of 50Hz informs the ECU or PCM there is no ethanol, a frequency of 150 HZ prsents the ECU of 85% ethanol.
The PCM converts this over to what fuel and spark map to use. By using the maps identified by the fuel compositon, the correct table will be used for the appropraite fuel sensed. This table will keep the injectors open longer and advance the spark. The burn content will be analyzed by the O2 sensor and compare to the the volume and density of air entering, which will adjust the for the stoichiometric ratio.

Since these are flex fuel vehicles, and ethanol does not have the output along with the higher octane the ECU's can only handle a certain badwidth.

If it were a pure E85 vehicle the compression surely would be raised along with a unique table and bandwidth for ethanol only vehicles.

So even though you are partially correct it's not done as you say it is. Since these are flex fuel and can adjust for 85% down to 15% ethanol, it's more ECM oriented then anything else.

 

I never said it didn't. I said it could, theoretically, be negated with higher compression ratio, which current FFV's do not take advantage of.

You are only partially correct here. Higher compression ratio does make full use of the octane. You understand this part ok. But you're failing to differentiate between fuels. Ethanol is a completely different fuel than gasoline, so burn temperature vs. octane is thrown out the window. The fact is that when burn at stoichiometric ratios ethanol and ethanol blends release more BTU's than gasoline burn at it's stoichiometric ratio. Therefore, ethanol actually burns hotter, producing more power.

I think it was simply because they needed to use a larger injector for flex fuel applications, not materials compatibility. Then they used these on non-FFV's to keep things simple.

I'd like to know where that came from.

Yep. And it works great on most vehicles which are converted. I have yet to hear of one fuel leak caused by E85 in a converted vehicle.

Now would that be a conductivity sensor, or did they change to something else? Do Ford FFV's really advance the spark with E85? I heard on other sites, by people that looked at the factory programs, that they do not.

What? I think you're confusing octane for energy content.

Cant argue with that.

What isn't done as I say it is?

 

It is hurting farm more farmers than it is helping. If you don't raise corn, you're up the creek. My neighbor is a dairy farmer and even though he only milks 150 cows, the cost of feeding them is ruining him. Same with my brother who raises beef cattle.

People can adjust their driving habits far easier than they can adjust their eating habits. As food goes up, people substitute cheaper food that is generally higher in fat and calories than

 

To keep from going thru this all over again, since you are a little off on your understanding and what I posted. I am not confusing ethanol with octane and power.
My comment was that ethanol has more octane but due to limitations of multiple types of fuel the octane can not be used to tune to it's full potential in FFV. No ehtanol does not have more BTU's then gsoline at 14:1. Ethanol contains 76,000 Btu’s per gallon, while 87 octane gasoline contains 114,000 to 124,800 Btu’s per gallon, diesel contains 140,000 Btu’s per gallon. So your comment is wrong. Sorry better do more research. Ethanol is not as volatile as gasoline in it's pure state.

Yes Ford does use the fuel and spark map that relates more to the ethanol content. Based on sensor input and the amount of ethanol in the fuel will tell the ECU what mao to use. Keep in mind there a limitations to these maps since there are multiple fuel contents that can be used.

The injector changover had nothing to do with volume, since more full is controlled by the pulse time on the injectors, which is part of the E85 fuel map. It was due to the ethanol content and it's corrosive properties. Makes not sense to have a larger injectior especially when these vehicles can run on pure gasoline down to E85.

 

You're not understanding what I posted!

Yes, ethanol has lower BTU's than gasoline. But when ethanol is burned in an engine at it's stoichiometric ratio, which is not 14:1, it will release more energy than gasoline burning at 14:1. Ethanol at 9:1 releases more energy than gasoline at 14.7:1. It's that simple. That's what I said, and you're misinterpreting my posts for some reason.

You are right that ethanol's octane cannot be utilized in an FFV. We agree there. I was saying that theoretically, higher compression could utilize the higher octane. I think you misinterpreted this too.

Because ethanol requires a richer mixture than gasoline, it requires a greater volume of fuel. It would follow that moving from the non-FFV injectors to the FFV injectors would require a greater flow rating. Normally fuel injectors are run at a maximum of 80% duty cycle. If you suddenly demand 30% more fuel from an injector already at 80% duty cycle, what happens to it? It overheats and dies an early death. Now unless they were using injectors that were too large, or had extra capacity, on the pre-FFV motor, they had to increase the injector flow rating when moving to the FFV application, then adjust the computer for shorter pulse widths on gasoline.

 

I think we should differentiate between 100% pump gas vs. 100% ethanol and E85, which would have properties (I think?) comparable to its 85/15 ratio. Perhaps that would align the discussion better with the real-world application we are discussing, namely, the effects of E85 vs. 87-Octane gasoline in the FFV F150. So if anyone has the E85 numbers for comparison (e.g. BTU rating for E85 and not 100% ethanol) that would provide information more germane to the present discussion.

I do applaud you gentlemen for keeping the discussion fact-based and not resorting to ad hominem attacks. In order for us to make an informed choice of fuels, we should look at the actual numbers for E85, since the FFV won't run on Ethanol alone (or will it?).

As for the effects on U.S. Farming, I think a conversion to plant-derived fuels needs to proceed with a lot of caution, lest we create a solution with more problems than we have now. I am reminded of efforts to introduce non-native species for short term solutions (e.g. Kudzu for erosion control at U.S. military bases) for their lesson in the consequences of changing the status quo in haste. I'm no fan of Kuwaitis, Saudis, or other non-American entities getting wealthy at the expense of U.S. consumers, but the decision to make a drastic change should be done pragmatically, with limited emotional influence.

 

I agree with this 100%.

As to pure EtOH, yes, there is such a beast in the fuel lexicon. It's called E100. Although it is perfectly possible for an IC engine to be built that runs very well on E100, I'm not sure that an FFV design has sufficient bandwidth in its fuel variation characteristics to run anywhere from 100% gasoline to 100% EtOH. For one thing, gasoline and EtOH are not infinitely soluble, so at some point, the fuel could split into two separate phases. Trace amounts of water in the EtOH would have a large influence on this, so the actual fuel mixture to the engine could change drastically and quickly as the fuel sloshes around in the tank while driving... probably not a good situation for drivability / engine efficiency.

Ed

 

Bad assumption that the extra pulse length would exceed the duty cycle. Heres the FFV explaination from Ford Media. You will notice the fuel injectors are mentioned:

"An FFV needs some special upgrades to avoid corrosion and wear," Seiter said. "The fuel tank, for example, is either plastic or has a special coating. Fuel lines are nylon 6 or stainless steel, the fuel injector is alcohol-tolerant, valves and seats are harder, and in some cases the head gasket must be more robust because combustion pressures increase more rapidly with ethanol."

"A sensor detects a refill event, in other words when the customer puts fuel into the tank," Seiter said. "The electronics in the system are basically a rapid learning center. Usually within a mile or two of the vehicle being driven away, the system learns what fuel is being used by the way the vehicle operates and adjusts the air/fuel mixture accordingly."


This maps to exactly what I have posted. The injectors were changed to accomodate the corrosiveness of ethanol and the majority is ECM control.

Heres the article:

http://media.ford.com/article_display.cfm?article_id=23401

 

Thank you for linking an article.

So what does this mean for the many people who have converted their vehicle to run on E85, and not had problems? See here: http://e85vehicles.com/e85/