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Converting to E85 (ethanol fuel)

frpe82 said:
No. The narrow band lambda sensor doesn?t have a clue about AFR, only lambda.

The ECU will tune to lambda=1 on idle regardless of the fuel used, and lambda=1 for E85 is 9.8.
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I'm sorry. I know this has been covered and I'm not trying to be difficult here(I appreciate the write up!), but I don't understand how the O2 sensor can compensate. The ecu doesn't tune for lambda, it tunes for 450mv. O2 sensors use the difference in outside air and exhaust air oxygen content and output a signal voltage based on that. Oxygen content increases with AFR. It does not spike in any way at lambda. If the amount of flow remains the same, and the fuel content increases, the O2 content will decrease. The ECU will not change it's desired reading of 450mv. Maybe I'm missing something here. I have to confess I didn't read all 6 pages. Thanks in advance for any clarification you can give me.:-P
 
Tomslide50 said:
I'm sorry. I know this has been covered and I'm not trying to be difficult here(I appreciate the write up!), but I don't understand how the O2 sensor can compensate. The ecu doesn't tune for lambda, it tunes for 450mv. O2 sensors use the difference in outside air and exhaust air oxygen content and output a signal voltage based on that. Oxygen content increases with AFR. It does not spike in any way at lambda. If the amount of flow remains the same, and the fuel content increases, the O2 content will decrease. The ECU will not change it's desired reading of 450mv. Maybe I'm missing something here. I have to confess I didn't read all 6 pages. Thanks in advance for any clarification you can give me.:-P
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The swing back and forth at around 450mV is Lambda=1 regardless of fuel used. The O2-sensor doesn?t read differently just because E85 is used.

So to conclude: 450mV is Lambda=1, and 450mV is what the ECU is trying to achieve all the time at idle and cruise.
 
The assertion of a Lambda value requires not just knowledge of oxygen but also of the fuel. Otherwise it would not occur at a specific afr for a specific fuel. Oxygen sensors do not measure fuel, only oxygen. Therefore O2 sensors don't detect or output any reference to lambda. These associations are done by math. If the air/fuel ratio changes, the oxygen level changes, and the O2 sensor voltage output changes, and the ecu will tune back to that same amount of oxygen(450mv). You will be left with the same afr as with gasoline, in which case you will be too lean.

Can anyone point me in the direction of any tech info that says that narrowband O2 sensors directly read and output lambda? Such a sensor would have to ignore oxygen level readings and measure fuel to compensate for what lambda is on said fuel, if the output voltages remain the same.
 
Tomslide50 said:
The assertion of a Lambda value requires not just knowledge of oxygen but also of the fuel. Otherwise it would not occur at a specific afr for a specific fuel. Oxygen sensors do not measure fuel, only oxygen. Therefore O2 sensors don't detect or output any reference to lambda. These associations are done by math. If the air/fuel ratio changes, the oxygen level changes, and the O2 sensor voltage output changes, and the ecu will tune back to that same amount of oxygen(450mv). You will be left with the same afr as with gasoline, in which case you will be too lean.

Can anyone point me in the direction of any tech info that says that narrowband O2 sensors directly read and output lambda? Such a sensor would have to ignore oxygen level readings and measure fuel to compensate for what lambda is on said fuel, if the output voltages remain the same.
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Lambda=1 for gasoline: Air/fuel ratio of 14.7:1
Lambda=1 for E85: Air/fuel ratio of 9.765:1

The O2-sensor sees the equivalence ratio and outputs the same voltage when the mixture is at Lambda=1 regardless of fuel.

Please read up on how O2-sensors work.
 
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As I posted, please point me towards technical documents that say that an o2 sensor sees an "equivalence ratio", and not just oxygen content. I googled for a couple hours trying to prove myself wrong before posting. I'm not trying to clutter this thread, but please show me some technical O2 sensor documents so I can understand how. Or you could explain how an O2 sensor measures anything more than oxygen. Again, not trying to be argumentative(it's my nature), I just want a "how" instead of "O2 sensors read lambda".
 
http://www.motorlexikon.de/

Die Spannung, die ?ber eine ZrO2-Schicht abgegriffen wird, h?ngt nur von der Differenz der Sauerstoffpartialdr?cke auf beiden Seiten der Schicht ab.
=
the voltage, measured over a ZrO2 layer, is only dependant of the difference of partial pressure of oxigen of both sides of the layer.

maybe that helps?
or walk in a uni-bookstore and find a book about engine management? not everything is easy to find on the net...
 
Tomslide50 said:
As I posted, please point me towards technical documents that say that an o2 sensor sees an "equivalence ratio", and not just oxygen content. I googled for a couple hours trying to prove myself wrong before posting. I'm not trying to clutter this thread, but please show me some technical O2 sensor documents so I can understand how. Or you could explain how an O2 sensor measures anything more than oxygen. Again, not trying to be argumentative(it's my nature), I just want a "how" instead of "O2 sensors read lambda".
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Yes, the O2-sensor reads the oxygen content in the exhaust stream. When the fuel has a complete/correct burn, it will be at the same equivalence ratio as any other fuel. Burn gasoline at an AFR of 14.7 and it will have an equivalence ratio of 1. Burn E85 at an AFR of 9.765 and it will have an equivalence ratio of 1.

The oxygen sensor doesn?t care about the fuel used, only the oxygen content. And the oxygen content is the same in all fuels exhaust gasses at a complete burn.
 
So an engine running a stoichiometric mixture on e85, and an identical engine running stoichiometric on gasoline, will(ideally) have the same % of oxygen in the exhaust despite drasticly different air/fuel ratios?
 
If someone can answer my above question "yes", then it makes sense and we can move on. But if they wouldn't have the exact same O2 % in the exhaust, then the reading will not be the same at stoich for the different fuels. I have read the wikipedia links. The only places that say that O2 sensor compensate to lambda are in forums and on wikipedia(you can put whatever you want on wikipedia without proving it to be true). I have taken classes at automotive school on ecu diagnostics, 5 gas fundamentals, and so forth as well as countless hours of internet research. I know basic operation. I seem argumentative, but I really just want complete clarification supported by explanations from credible sources. The only way that that could be right is if both engines in my example would have the exact same % of oxygen in the exhaust in spite of different AFR's. So, is this the case?
 
Tomslide50 said:
If someone can answer my above question "yes", then it makes sense and we can move on. But if they wouldn't have the exact same O2 % in the exhaust, then the reading will not be the same at stoich for the different fuels. I have read the wikipedia links. The only places that say that O2 sensor compensate to lambda are in forums and on wikipedia(you can put whatever you want on wikipedia without proving it to be true). I have taken classes at automotive school on ecu diagnostics, 5 gas fundamentals, and so forth as well as countless hours of internet research. I know basic operation. I seem argumentative, but I really just want complete clarification supported by explanations from credible sources. The only way that that could be right is if both engines in my example would have the exact same % of oxygen in the exhaust in spite of different AFR's. So, is this the case?
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Yes. At Lambda=1 for both gasoline and E85 the relative O2 content is the same.
 
n

frpe82 said:
Yes. At Lambda=1 for both gasoline and E85 the relative O2 content is the same.
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I a Xavier ,I live in Paris and and I want to convert my grand cherokee 4 litre to E85
without kit
I want to increase the tension to my MAP sensor , to increase quantity of the fuel into the injectors with a potentiometer in my dashbord , because I put E85 or fuel ?
Xavier
 
xav78 said:
I a Xavier ,I live in Paris and and I want to convert my grand cherokee 4 litre to E85
without kit
I want to increase the tension to my MAP sensor , to increase quantity of the fuel into the injectors with a potentiometer in my dashbord , because I put E85 or fuel ?
Xavier
Click to expand...
To make that possible on a naturally aspirated car with a MAP-sensor you would have to make some modifications...

The MAP-sensor will probably max out at atmospheric pressure (normal ambient pressure), or just a little bit above that. The ECU will also not be able to correct anything if you were to put a potentiometer in-line with your MAP-sensor. The only thing you would do would be to get more fuel up to a certain point, and then the MAP would max out and the air/fuel mixture would go lean.

You should get a MAP-sensor that reads around 40-45% higher (relatively) to the stock MAP-sensor. That way you can probably run the car on E85. Then you need to make a resistor setup to put in line with the MAP-sensor that you can switch on and off to be able to run on gasoline again. You need to experiment with how much resistance you need to put in line with the signal from the MAP-sensor.

I am sorry that I can?t give you a more detailed answer, but I don?t know exactly what it looks like in your car. But what I have said now is at least something to start thinking about as a basic thought.
 
frpe82 said:
To make that possible on a naturally aspirated car with a MAP-sensor you would have to make some modifications...

The MAP-sensor will probably max out at atmospheric pressure (normal ambient pressure), or just a little bit above that. The ECU will also not be able to correct anything if you were to put a potentiometer in-line with your MAP-sensor. The only thing you would do would be to get more fuel up to a certain point, and then the MAP would max out and the air/fuel mixture would go lean.

You should get a MAP-sensor that reads around 40-45% higher (relatively) to the stock MAP-sensor. That way you can probably run the car on E85. Then you need to make a resistor setup to put in line with the MAP-sensor that you can switch on and off to be able to run on gasoline again. You need to experiment with how much resistance you need to put in line with the signal from the MAP-sensor.

I am sorry that I can?t give you a more detailed answer, but I don?t know exactly what it looks like in your car. But what I have said now is at least something to start thinking about as a basic thought.
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Thank you for your email
My MAP sensor (grand cherokee 4 l) is like the MAP sensor in this web site

http://go.jeep-xj.info/HowtoMAPsensor.htm

The lenght of the injection is inversely proportional of the depression

Another ex to reduce consumption but increase the pollution

MAP adjuster

The stock MAP sensor input voltage was 5.05v. I reduced the voltage in small steps in order to shorten the injector duty cycle and correct the rich condition. I finally settled at a MAP input voltage of 4.15v. At that voltage, the air/fuel ratios at idle and under light throttle cruise conditions were 15.5-16.3:1, right at the optimum level for best gas mileage. Not surprisingly, average gas mileage improved to 20.8mpg and I'm very happy about that. This was a very cheap mod and it works beautifully.

At idle you have 1 volt and at the maximum of power of the motor you have 5 volts
so I put 1 volt more and the AFR increase for a speed done

I hope that you understand because my english is not very good
Xav 78
 
E85 is energy negative, it generally uses more non-renewable resources to produce than it saves. E85 has a host of other economically and energy problems as well. Look it up. Google "problems with E85" and look hard at some of the true envirosites.
 
ACES70 said:
E85 is energy negative, it generally uses more non-renewable resources to produce than it saves. E85 has a host of other economically and energy problems as well. Look it up. Google "problems with E85" and look hard at some of the true envirosites.
Click to expand...

booya. The octane rating is high, thats more important :-P

indeed, a lot of energy is needed to produce E85. but if it is a s bad as some sites suggest i don't know.
 
What kind of fuel lines is needed for E85? Is rubber no go? What kind of material do I ask for?

Are the Walbros and Bosch motosport pumps ok for E85?
 
RS1 said:
What kind of fuel lines is needed for E85? Is rubber no go? What kind of material do I ask for?

Are the Walbros and Bosch motosport pumps ok for E85?
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Stock lines are as good as any other lines. The only lines and components that can't stand E85 are the ones that are 25-30 years or older, and those should be replaced anyway so...

Walbro and Bosch pumps work like they should on E85, so no worries there.
 
I have heard no rubber and no bare aluminum in the system. New "rubber" fuel lines that they sell nowadays, do they have a rubber that can withstand ethanol?
 
RS1 said:
I have heard no rubber and no bare aluminum in the system. New "rubber" fuel lines that they sell nowadays, do they have a rubber that can withstand ethanol?
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No problems.

It is no more corrosive than gasoline.

What you are probably thinking of is Methanol. That is highly corrosive.
 
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