Oh well. Best of luck.Originally Posted by samgm2
When the GM Goodwrench mechanics can tell you why GM uses hard sensors on 2011 vehicles when they could use VFS, please share the thinking with all of us. Current OS's support both hard and virtual sensing. And agreed, it IS in the software. If GM Goodwrench mechanics can tell you where, that would be great to know.
Which 2011 GM vehicles use a hard fuel composition sensor?
Oh well. Best of luck.
If you are in the US you would know them as Pontiac G8. Holden Commodore. V6 and V8 models. Also known as Chevrolet Lumina in Middle East and Sth Africa.
The G8 was introduced in the US in 2008 and was produced until 2009 (2 years).
In addition, a search of alldata reveals that no fuel composition sensor was used in either year.
The Lumina was discontinue in 2001 in the US.
I have yet to verify the use of a fuel composition sensor after 2002, although I have found references to a couple in 2006. That said, there are inaccurate references in this thread for cars made in 2011.
That means the hard sensor has been gone for AT LEAST seven years in all cars and in most cars for more than a decade. So why would new computers support it?
The use of a hard fuel composition sensor in any vehicle is ill-advised. We should turn our attention to enabling the virtual function in ALL vehicles.
My experiments with E-85 tunes reveals that with proper advance (12-18 degrees), E-85 yields equivalent or superior mileage and power to gasoline.
Estimates of mileage based on combustion energy alone, border on meaningless. Equally important is the reversibility of the reaction. Alcohol burns much slower and is thus much more efficient for converting heat to energy.
There has GOT to be a parameter that turns the virtual composition sensor on.
Once I deal with VATS, I will test a 2009 Flex Fuel E-37 with a non flex fuel 2007 Cobalt. Either it will work or it will not.
If it works, it means that the function is FULLY enabled by software and we just haven't found all the parameters to enable it. If it doesn't, it means that an external signal is missing in the non-flex fuel vehicle.
If it is fully in software, I would guess that there may be a hunting rate parameter or a loop gain(s) parameter(s) that may have zeros in it (for non FFV).
Sam
Chemical/Controls Engineer
Sam, don't take this the wrong way, but do some OVERSEAS GM vehicle research.
Check out Holden, Vauxhall and Chevy in other countries. The overseas Lumina is
a re-bagged 04-06 GTO.
-Justin
The 2011 Holden Commodore (G8 basis until Pontiac shut its doors, but coming back as the Chevy Cop Caprice) V6 and V8 flex fuel cars use a hard sensor (IIRC that may be all models for 2011). It can be purchased NOW as a spare at a GM/Holden dealer for the 2011 cars. The information, oddly enough, is accurate.
Really interested in how you manage to get better mileage out of E85 than gasoline when at stoich its flowing roughly 45% more fuel by weight.
VFS CAN be turned on in GM controllers. EFILive opened this door maybe 2 years back. It just doesnt want to work as it should. Even tried stock FF tunes and VFS wont run. So yes, there is an input missing as you mention that it needs to validate the process and then run the learn cycle. It uses both fuel level and fuel tank pressure to commence the cycle...though now I cant remember for sure whether I ran a simulation as well for the fuel tank pressure. Maybe I didnt. It was about a year back. Must swap the E67 out and put an E38 back in and give it shot again.
And as LS1Sleeper pointed out, just because something isnt available in the US, doesnt mean it isnt available somewhere else on the planet where the other 95%+ of the inhabitants of earth hang out. The rest of the world is not the 52nd and 53rd states of the US), south africa, and the car the G8 was derived from is the largest selling car in Australia, and also exported to the UK and Singapore and middle east countries (Chevrolet Luminas), etc, in some forms.
Last edited by gmh308; June 30th, 2011 at 10:06 PM.
Relax a bit. This isn't a battle. If as a group we are able to find out why the flex fuel function isn't working, this will be good for everyone.
If Efilive can play a significant role in this???...
Or... would we rather continue to supply the middle east with oil dollars while at the same time the NON OPEC countries continue to be bled?
Yes, you can get better mileage from E-85 because the reaction is more reversible. I currently lead a design effort for an engine based on E-85, E-100 and M-100 (Methanol). The efficiency of a pure methanol engine running at high compressions is more than twice that of gasoline!
Yes, the energy content of the fuel is primary in determining mileage. Just as important however are:
1. The reversibility of the reaction.
2. The compression ratio.
The brake efficiency of a gasoline engine (assuming reversible conditions) is only 18%. The brake efficiency of an alcohol engine (at a CR of 20:1) is 48%! This exceeds even diesel which sits at 40%.
Gasoline is lousy fuel. Alcohol is superior in nearly every respect. Methanol trades for about $1.00 per gallon and the US currently produces more than 3.6 Billion gallons per year of it from Natural Gas. This is a fuel we can make rapidly here in the US.
Since I am talking only about code modification in this case and I am not altering the compression ratio. The gain in efficiency is due ONLY to the far more reversible reaction that takes place with Alcohol fuels. So yes, despite the fact that the energy content of E-85, a greater percentage of the energy in E-85 will convert to useful work.
In an Ecotec 2.2 liter engine the following resulted in a dramatic increase in mileage for E-85.
1. High octane spark table copied into low octane spark table.
2. Added additional 8 degrees to low octane spark table.
3. Added 12 degrees to high octane spark table.
Additionally, I have been heading a research effort at my company and have developed an optimized procedure for determining optimal spark. Once completed, I will release the algorithm (and likely, the full program) to the public.
Finally, your logic that at a particular flow rate of air the E-85 required will be 45% more than gasoline is flawed. That assumption presumes the same efficiency. What I am saying is that you will need less air and therefore less E-85 to make the same power because efficiency has increased.
Sam
Chemical Engineer/Research Scientist
The 2011 Holden Commodore (G8 basis until Pontiac shut its doors, but coming back as the Chevy Cop Caprice) V6 and V8 flex fuel cars use a hard sensor (IIRC that may be all models for 2011). It can be purchased NOW as a spare at a GM/Holden dealer for the 2011 cars. The information, oddly enough, is accurate.
Really interested in how you manage to get better mileage out of E85 than gasoline when at stoich its flowing roughly 45% more fuel by weight.
VFS CAN be turned on in GM controllers. EFILive opened this door maybe 2 years back. It just doesnt want to work as it should. Even tried stock FF tunes and VFS wont run. So yes, there is an input missing as you mention that it needs to validate the process and then run the learn cycle. It uses both fuel level and fuel tank pressure to commence the cycle...though now I cant remember for sure whether I ran a simulation as well for the fuel tank pressure. Maybe I didnt. It was about a year back. Must swap the E67 out and put an E38 back in and give it shot again.
And as LS1Sleeper pointed out, just because something isnt available in the US, doesnt mean it isnt available somewhere else on the planet where the other 95%+ of the inhabitants of earth hang out. The rest of the world is not the 52nd and 53rd states of the US
I would love to give money money to the farmers up in Queensland who produce our E85 fuel as you would like to see your money go to local US farmers, but when the cost price does not out way the additional fuel used what is the point?
For me, the Australian government stuffed up on the pricing. By my calculations, the extra fuel used on E85 it needs to be priced about 35 - 40 cents per litre cheaper, currently it's only 20.
I think I recall Buick marketing the direct injection turbo 4 in 2012 will get the same fuel economy on regular or E85.
I have been contemplating doing some serious tuning on my car on E85 to try to get the fuel economy better, but I don't 100% understand the ideal calculations on fuel ratios and timing for E85.
I no longer monitor the forum, please either post your question or create a support ticket.
Ditto. In Sydney 10c per litre differernce at one station tonight :(. E85 costs more to run that regular ole gasoline.
.
Last edited by gmh308; July 4th, 2011 at 10:49 PM.
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