E85 Auto-Calibrate

Reply Subscribe

Thread Tools

Search this Thread

Apr 16, 2010 | 02:08 PM

dyezak

Thread Starter

Evolving Member

iTrader: (3)

Joined: Mar 2010

Posts: 253

Likes: 0

From: Plano TX

E85 Auto-Calibrate

I posted this in the ECU-Flash forum but think I put it in the wrong place, so I'll stick it here

I don't know what else to call it other than "Auto Calibrate for E85". But stock flex fuel vehicles do this. If you are at 1/2 tank of gas and fill up the rest of the way with E85 the ECU's calibrate for the change in fuel and automaticly adjust for the fluctuations in fuel composition. From what I can tell the ECU uses O2 feedback to determine the ethynol percentage in the fuel and adjusts the fuel map based on that. I may be wrong about that but it's how I understand it to be possible.

Is there any chance of us using a wideband feed to perform the same operation and automaticly adjusting the tune for ethanol content?
I was basing that statement on this article:

http://www.canadiandriver.com/2006/03/22/auto-tech-chevrolet-impala-e85-flex-fuel-system.htm[/URL]

Quote:

GM has developed a Virtual Flex Fuel Sensor (V-FFS) software program that calculates the ethanol content in the fuel, instead of using a sensor to measure it. When the fuel level in the tank increases as the vehicle is refueled, the computer recalculates the percentage of ethanol in the fuel and automatically changes the air/fuel ratio. To do this, the computer temporarily stops the operation of other emission systems and monitors the oxygen sensors to determine ethanol content. The test is done several times until calculations remain stable. This can take several minutes when the engine is idling, but much less time at higher fuel flow rates.

Apr 16, 2010 | 02:44 PM

andrewzaragoza

Evolved Member

iTrader: (6)

Joined: Mar 2007

Posts: 1,019

Likes: 2

From: DFW, TX

this has been discussed before on the ecuflash section. having an eca connected to the ecu and tephra doing his magic this is very possible.

Apr 16, 2010 | 03:03 PM

goofygrin

Evolved Member

iTrader: (5)

Joined: May 2008

Posts: 3,125

Likes: 4

From: Frisco, TX

It uses an ethanol content sensor. This basically determines the % of ethanol and the temperature of the gas and sends that as a signal to the ECU. The ECU reads that and then changes the timing in order to use the fuel appropriately.

Apr 16, 2010 | 07:11 PM

logic

Evolved Member

iTrader: (2)

Joined: Apr 2003

Posts: 1,022

Likes: 7

From: Berkeley, CA

Your original thread..

As I said over there, mrfred was originally investigating this (I suspect it's what led him to spend so much time with the fuel routines in the first place), but I have a feeling real life has been catching up to him lately.