Flex Fuel : How To Tune With It

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HaltechMatthew
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Flex Fuel : How To Tune With It

Postby HaltechMatthew » Thu Dec 13, 2012 2:38 pm

This is starting out as an intro guide to explain the process of tuning with a flex fuel sensor. It may be altered or expanded as required.

What You Need to Use Flex Fuel

1x PC with Haltech ECU Manager V1.12 or newer installed
1x Haltech Platinum Sport or Platinum Pro Plug-In ECU
1x Available Digital Pulsed Input (DPI)
1x Haltech Flex Fuel Sensor

Some Pro Plug-In models have a DPI and some do not. If your model does not have a DPI a CAN based IO12 Box can be added to your system which will have a DPI.

After wiring and installing the sensor you must enable it in the software. To do this :

1. Go to your Main Setup ("F4" is the shortcut key)
2. Select Inputs
3. Enable the DPI you have wired the sensor to by ticking the box, and then select Digital Fuel Composition Sensor from the list. From V1.12 the default calibration will be correct.
4. If prompted to reboot the ECU, you can either key off and on the ignition key, or simply hit "CTRL F12" which is the shortcut key to reboot the ECU.
5. The Flex Fuel Sensor will now be read by the ECU.
6. Go back to the Main Setup
7. Select the Advanced section
8. Enabled the Composition Correction Tables for Fuel, Ignition, and Boost (if required)
9. Reboot the ECU if Prompted

Now you are ready to begin tuning....

Generally, Haltech recommends all base tuning is done first with regular fuel, and the ethanol is added after this. The tuning can however be done the other way around if required, which just causes the mapping to look inverted.

I have attached a Page Layout that has some of the Flex Fuel data channels visible. This is optional but you may add this to your system if you would like.
Flex Fuel.zip
Haltech ECU Manager Page Layout for Flex Fuel. Unzip and add to your Haltech/Page Layouts Folder
(622 Bytes) Downloaded 525 times



How The Mapping Works

There are two tables each for Fuel and Ignition and one table for Boost correction. These tables do the following functions:

Fuel
Fuel Composition Correction - This is a 3D table which is typcially mapped as RPM vs Load (MAP or TPS). This map will have fuel correction values to cover the highest possible ethanol content that you will run. It allows you to trim the fuel side of the tune under different load conditions to get the AFR that you want.

Fuel Composition Scalar - This is a 2D table mapped versus Ethanol Content. It reflects what percentage of the 3D table is applied based on how much ethanol is in the fuel. 0% means it does not use the 3D correction values, 53% means it uses 53% of the values in the 3D corretion table, 100% uses 100%, etc... So in effect, as more ethanol is added, more of the correction table is applied.

Ignition
Fuel Composition Correction - This is a 3D table where the timing is altered (in degrees) over RPM and Load to suit the most possible ethanol you can use. As ethanol content increases the octane rating of the fuel also raises to a point. This together with a different rate of combustion means a more advanced ignition timing can be run.

Fuel Composition Scalar - This is a 2D table mapped versus ethanol content, and it works the same as for the Fuel table of the same name. It allows you to control how much of the 3D table is applied based on ethanol content. At 0% ethanol you will not use the trim table so it will be set to 0%, and as content rises so to will the percentage until you hit 100% where it will use all of the 3D table.

Boost
Adjustment with boost control will depend on whether you are using Open or Closed Loop control. The method is the same for both.

Fuel Composition Target Correction - Used when in Closed Loop it allows you to adjust the Boost Target based on ethanol content.
Fuel Composition Duty Correction - Used when in Open Loop and it allows the Duty to be corrected based on ethanol content.


The default values that come with the base maps for V1.12 and newer versions have settings that will be reasonably close without modification, so these are a great starting point and give you a good idea of how the tables should look. If the injector flow rate and/or the dead time is not set correctly the numbers in the Flex Fuel tables may also need to be modified to suit.

JohnPS
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Joined: Thu Jun 25, 2009 3:31 am

Re: Flex Fuel : How To Tune With It

Postby JohnPS » Thu Dec 13, 2012 5:27 pm

Mapping is great with this method of Correction-Scalar tables...
Very useful function...thanks...

So we set "Digital Fuel Composition Sensor" to a DPI when the sensor outputs a pulsed output and set an AVI to "Fuel Composition Sensor" if we have a controller that converts frequency to voltage??

(by the way it is said that pulse width indicates the fuel temp..is this implemented?)

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HaltechMatthew
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Re: Flex Fuel : How To Tune With It

Postby HaltechMatthew » Fri Dec 14, 2012 8:13 am

That is correct, if you have an analogue 0-5V system you can use that for your fuel composition source on a AVI.

Fuel Temp can be read by the Pro Plug-In range but not by the Sport ECU. This can then be added to the mapping via a Generic table if you wish to compensate for Fuel Temp.

trfwelding
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Re: Flex Fuel : How To Tune With It

Postby trfwelding » Mon Dec 24, 2012 12:57 pm

HaltechMatthew wrote:That is correct, if you have an analogue 0-5V system you can use that for your fuel composition source on a AVI.

Fuel Temp can be read by the Pro Plug-In range but not by the Sport ECU. This can then be added to the mapping via a Generic table if you wish to compensate for Fuel Temp.

ok i know how to setup the flex fuel sensor 50hrz=0% and 150hrz=100% ethonal but what is it for the digital fuel temp. how do i set that up what numbers do i punch in.

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HaltechMatthew
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Re: Flex Fuel : How To Tune With It

Postby HaltechMatthew » Tue Jan 08, 2013 12:48 pm

If it is a Pro ECU then you can read the temperature by simply adding the calibration file for it. The latest software comes with these calibrations all done ready to use.
If it is a Sport ECU it is not capable of reading the temperature.

crum86
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Re: Flex Fuel : How To Tune With It

Postby crum86 » Thu Mar 03, 2016 11:26 pm

Just wondering if the sport was capable of reading fuel temp from the ethanol sensor yet since there have most likely been firmware updates since this thread was posted

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HaltechMatthew
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Re: Flex Fuel : How To Tune With It

Postby HaltechMatthew » Fri Mar 04, 2016 8:53 am

No. The hardware is not capable of handling both signals.


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