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Will the Flexi fuel vehicles able to run with methanol 3
- Thread starter Azmio
- Start date
- Thread starter
- #21
TDIMeister
Automotive
Yes, it will "run". Does the quotes make it too vague again?
patprimmer
New member
TDIMeister
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
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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 for tips on how to make the best use of Eng-Tips Fora.
- Thread starter
- #24
I am under the impression that if the dielectric sensor senses the oxygen content of M56 to be not far from E85, there is no reason why the ECU cannot operate the engine much like an E85.
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.
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.
Azimo,
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
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
patprimmer
New member
If the timing on petrol is torque limited, I have not found that 100% methanol needs much more if any more advance than petrol. It is only when the compression is really to high for the octane of the petrol and the timing is retarded to cope that the methanol needs significant extra advance. At least that is my experience from observation on different engines rather than back to back tests. I have found that providing the octane is sufficient for the compression, modern after market Small Block Chevrolet heads like 36 to 38 deg all in petrol or methanol.
Regards
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Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
- Thread starter
- #27
Matt,
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.
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.
I found this thread and read it with great interest. I have begun testing in my own vehicle-- an '07 Tacoma 4X4 with the 4.0 V6.
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.
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.
turbocohen
Automotive
I waited for months and dgallup wins the prize here. Methanol will decimate the fuel system and lead to rapid overall engine deterioration. Oil will need to be replaced far more often 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..
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..
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