Will the Flexi fuel vehicles able to run with methanol
Will the Flexi fuel vehicles able to run with methanol
(OP)
Hey guys,
I know that FFV can run easily with ethanol, will it be possible to run FFV with M85 or M100 too?
I know that FFV can run easily with ethanol, will it be possible to run FFV with M85 or M100 too?





RE: Will the Flexi fuel vehicles able to run with methanol
RE: Will the Flexi fuel vehicles able to run with methanol
RE: Will the Flexi fuel vehicles able to run with methanol
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Will the Flexi fuel vehicles able to run with methanol
AS for the E85, whichever in contact with fuel will not be made out of plastic or aluminum but preferably steel. The question still remains, will the current FFV built for ethanol capable of running with methanol?
RE: Will the Flexi fuel vehicles able to run with methanol
Even mild steel will corrode in contact with methanol or ethanol, but it corrodes faster in methanol as the methanol absorbs more water more quickly.
If rust resistant steel parts are used in contact with the fuel, it should be OK
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Will the Flexi fuel vehicles able to run with methanol
RE: Will the Flexi fuel vehicles able to run with methanol
well, unless it is possible to delete history, they did have fleets of methanol powered cars back in the 93s. It was a big thing during that time, try search the internet and you will many reports from the programs.
RE: Will the Flexi fuel vehicles able to run with methanol
RE: Will the Flexi fuel vehicles able to run with methanol
The current method of detecting the quantity of ethanol in the fuel is via a sensor placed in the fuel line that measures the impedance or dielectric constant of the sampled fuel.
htt
Gasoline has a range of dielectric constants due to its mixed composition, but it is in a fairly narrow range. Ethanol has a completely different dielectric constant, and by measuring this dielectric constant of the blended fuel and the known flow rate, it is possible to determine the mass fractions of ethanol and gasoline.
A somewhat simpler and less sophisticated method is to measure the change in stoichiometry at the oxygen sensor. Gasoline has a known stoichiometric AFR (~14.5-14.7:1); ethanol 9:1. If you know the fuel mass flow rate and the stoichiometric AFR, you can determine the mass fractions of the blended fuel.
The problem with methanol is that it has both a different dielectric constant AND stoichiometric AFR than ethanol. Remapping the respective values can remedy this, BUT you have maps holding ONE tranfer function, not more, so if you remap for methanol, you lose the transfer function for ethanol.
In a true Flex-fuel car to be able to also work with methanol in addition to ethanol, you have to now consider TERTIARY blends of gasoline, ethanol and methanol, and this cannot be addressed by remapping alone.
One solution would be to sense BOTH AFR and dielectric constant, and instead of 3-dimensional maps (fuel rate; dielectric constant OR stoichiometric AFR; mass fraction for two fuels), you have a 4-D map (fuel rate; dielectric constant AND stoichiometric AFR; mass fraction for 3 fuels).
Obviously, this is not a plug-and-play change...
This has further implications of truly optimizing engine operating parameters for the benefits of ALL the fuels used in their respective percentages over the entire operating range, but this adds yet another variable to be considered and optimized.
RE: Will the Flexi fuel vehicles able to run with methanol
The cars worked well in most conditions other than full load and engine start up. During these two conditions the ECU switched to open loop causing the ECU to look into the mapping table rather than to receiver feedback from the oxygen sensor
RE: Will the Flexi fuel vehicles able to run with methanol
"Methanol doesn't like staying mixed with gasoline."
Pure methanol and gasoline are quite miscible. The problem arises when water is included in the blend. Water can and will enter the fuel through normal weathering processes, and will go into solution due to the co-affinity between water and methanol. However, when the water content goes above a certain level, the solution will separate into 2 or three different phases. Engine operation will tend to deteriorate when this occurs.
RE: Will the Flexi fuel vehicles able to run with methanol
Getting the stoichiometry correct only tells you (the ECU) that you have the fueling quantity correct, but as you said, is useless at full-load when the mixture is enriched beyond stoichiometric or in lean-burn engines operating at part load.
To determine the actual AFR at closed-loop lambda=1, you need to know also know the instantaneous mass flow rate of the fuel AND air.
mass air = mass fuel * lambda * stoichiometric AFR
Actually, you can see that we have two unknowns, requiring two equations, but you can use use MAF sensor readings or time histories to come up with the other unknown.
Getting the amount of fuel correct is only one part; knowing the precise composition of the blended fuel has other optimizing implications. For example, if you know precisely how much gasoline, EtOH and MeOH you have in your fuel, you can also optimize the ignition timing maps, which you cannot do with only a knowledge of stoichiometry alone.
Additionally, you might put some intelligence into your ECU as well, for example knowing how different fuels react in cold start, and optimizing the measures accordingly. Or by knowing precisely the composition of the fuel, you can adjust the fuel pressure in the accumulator rail to maintain a constant injector duty cycle, etc., etc.
RE: Will the Flexi fuel vehicles able to run with methanol
In actual fact what you have described is a binary lambda sensor as opposed to the more modern wideband sensor.
Wideband lambda sensors have an integral O2 pumping circuit which allows, within reason, a meaurement of actual lambda. As opposed to the rich/lean output of a binary sensor.
One of the problems is that of fuelling adaptation. Whereby the ECU will implement a longterm trim factor to ensure that Lambda=1 is always achieved, useful in the prescence of air leaks etc. By using flexfuel or fuels of differeing stoich afrs these adaptions can quite easily reach the threshold of failure and the MIL will be illuminated.
MS
MS
RE: Will the Flexi fuel vehicles able to run with methanol
Yes, I know, and I specifically distinguished both in my second post above (although I called it "wide-spectrum" instead of wideband).
I don't know that wideband sensors have now displaced the original sensors I described. I thought they are mostly only used in lean-burn gasoline engines (which don't exist in North America) and new Diesels with PM and NOx traps.
RE: Will the Flexi fuel vehicles able to run with methanol
MS
RE: Will the Flexi fuel vehicles able to run with methanol
With the FFV fuel rail and tank being designed and developed to withstand gasohol corrosive nature, I just wondering why it is not possible for the current FFV to run with M60?
RE: Will the Flexi fuel vehicles able to run with methanol
If your FFV uses a dielectric constant ethanol sensor, it will get false readings for alcohol content in the blended fuel. The ECU could see what's going on with signals coming from the MAF-, fuel quantity- and Lambda sensors, and see that something doesn't jive in the stored maps with the signal from the ethanol sensor, and throw an out-of-range or implausible MIL fault. It might be fine on a SPECIFIC blend of methanol (e.g. M60 as you say), where the stoichiometry and other properties happen to coincide with an mapped ethanol/gasoline blend (it might not be specifically E85).
RE: Will the Flexi fuel vehicles able to run with methanol
Your question is not quite clear possibly due to fine meanings of words and inference. That is why some are saying what could possibly be done and others are saying what is done.
Do you mean can you run existinf FFV without modification on M50
Do you mean can you run an existing FFV with minimal tuning changes on M50.
Do you mean can you build an FFV with hardware components that could easily be produced if the demand existed to justify manufacture of the components suitable for M50 or M85.
Do you mean can the existing or new designs be made flexible enough to run petrol, E85 and M50 reliably and efficiently.
Different answers seem to have presumed some of these different options.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Will the Flexi fuel vehicles able to run with methanol
"If your FFV uses a dielectric constant ethanol sensor, it will get false readings for alcohol content in the blended fuel"
Is it the alcohol or the oxygen content that the sensor is sensing and feeding it back to the ECU?
" the engine will not run optimally with respect to ignition timing, etc. for methanol"
Normally, ignition timing, load and rpm goes hand in hand in the mapping table. The knock sensor on the other hand will push it further to the brink of mild knocking to really push the ignition timing to the limit.
The current FFV available are intelligent enough to be runned with gasoline, E50 and E85. Can anyone explain how it is being done?
RE: Will the Flexi fuel vehicles able to run with methanol
I think you understand my question really well by writing "Do you mean can you run existinf FFV without modification on M50" as your first question. I am just looking for an answer to this question.
RE: Will the Flexi fuel vehicles able to run with methanol
RE: Will the Flexi fuel vehicles able to run with methanol
I think dgallup said it would not run for long.
The answer seems fairly clear to me, so long as there is no attempt by the EFI system to analyse the fuel blend by impedance, it should run OK. The standard map ignition map plus knock sensor should give good if not perfect results
Durability problems may or may not exist at the M56 level due to methanol's similar characteristics, but at a more aggressive level when compared to ethanol.
Wide band O2 sensors will look after a:f ratio under most circumstances. Open loop will still be reasonable if the fuel is one of the following.
100% petrol
85% ethanol
56% methanol
I know E85 is not always 85% ethanol, hence a possible need for the impedance test as it will over ride the open loop map and will be predictive rather than reactive in adjusting a:f ratio. As an O2 sensor tests exhaust it is reactive and as a consequence has a slight time delay.
No one has mentioned correction to a:f ratio to correct for variations in water absorption.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Will the Flexi fuel vehicles able to run with methanol
When orbital published the test that it conducted, all of the cars tested were only equipped with HEGO sensor and the cars worked very well in conditions other than full load and start up.
RE: Will the Flexi fuel vehicles able to run with methanol
Hopefully the OP has been answered for you. There are, however, a couple of points that I would like to make: -
"The cars worked well in most conditions other than full load and engine start up. During these two conditions the ECU switched to open loop causing the ECU to look into the mapping table rather than to receiver feedback from the oxygen sensor"
In a gasoline engine fuelling during start is always open loop because the sensor will not have lit off, even with a heated sensor the dewpoint of the exhaust gas must first be reached before full heating can be used.
In a gasoline engine full load, with a HEGO sensor, is also open loop - since a binary sensor will only read rich/lean and full load is 99% of the time within the enrichment area the control can only be open loop.
"Normally, ignition timing, load and rpm goes hand in hand in the mapping table. The knock sensor on the other hand will push it further to the brink of mild knocking to really push the ignition timing to the limit."
This is not how a gasoline engines ignition system works. The spark will be set at a calibrated base timing which either corresponds to MBT or x degrees from DBL (emissions/driveability permiting).
If knock is then encountered the spark is retarded from this base timing and then readvanced stepwise until the base timing is again reached. At no point will the spark advance further than that which is already precalibrated. Hence the extra RON of the methanol will not result in more spark advance.
Since the greater amount of fuel required for stoich and the lack of the control systems ability to advance the ignition past the corresponding calibrated base timing for gasoline the BSFC will suffer tremendously.
MS
RE: Will the Flexi fuel vehicles able to run with methanol
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Will the Flexi fuel vehicles able to run with methanol
I have worked in production engine design and development for many different engine programs both in Japan and Europe. I am now busy doing some research work.
There is no issue about the open loop thing, i know for sure that the ECU will have several criteria like coolant temperature and predetermined time after start up before it can move to close loop from open loop. Even if your HEGO sensor is hot enough, the engine will still have to pass certain time period after start up.
One engine that we came across few years ago can easily change its ignition timing automatically for RON 88 up to RON 102 fuel. It all depends on the range of calibration that you do.
Anyhow, though methanol has a high RON rating, it's not necessary that the M60 or M85 will have very high RON rating if the gasoline itself has a low RON rating.
RE: Will the Flexi fuel vehicles able to run with methanol
I am running my own mix M15. (85% Premium 91 Octane Petrol and 15% pure Methanol)
Experiencing slightly improved fuel economy and much improved performance. I have no startup or warm up issues. No pinging and the only time my "check engine light" came on was when I pushed Methanol content to 20%. It reset itself while still running on M20 but I backed down to M15 for the next tank anyway.
I am testing and doing research because I am considering buying a large FFV Truck or SUV and want to run M60 or greater Methanol content.
RE: Will the Flexi fuel vehicles able to run with methanol
RE: Will the Flexi fuel vehicles able to run with methanol
Every methanol/gasoline demonstrator I know of ranged from a mere failure to an outright disaster in comparison to Ethanol/gasoline.
There was a cluster of fuel injector durability cyclers across the hall from the cng durability cycler I spent a few years working on. People would walk in and ask if what I was doing was safe and I said maybe.. are you wearing Depends?
Then the tech's working there, shook their heads and realized the real hazard was trying to replicate the california methanol blend without burning the place down..