[Diy_efi] WBO2 and AFR

gary gas-
Thu Jul 7 19:01:38 UTC 2005


----- Original Message ----- 
From: "Fehn, Ron G" <RFEHN at amfam.com>
To: <diy_efi at diy-efi.org>
Sent: Thursday, July 07, 2005 9:40 AM
Subject: RE: [Diy_efi] WBO2 and AFR


> Gary:  new to this stuff.  pulse width = the time injector is 
> open?  is that correct?  

So far, so good.

> so on my WB is see 14.3 in CL on 10% ethanol.  i will
> assume lambda is then reading = 1.0.  correct?  

Depending on whom and what figure you wish to believe in....Yes.

> the NB 02 adjusts A/F to stoich or lambda 1.0?  

No.  The NBO2 sensor identifies oxygen content, and sends a 
voltage signal to E/PCM.  E/PCM recognizes .45 V as stoich,
or 14.7 if straight fuel is used.

> if i run non oxy fuel nb02 will adjust A/F to 14.7 

No.  As I stated NBO2 sensor recognizes/identifies oxygen 
content.  The .45V noted above is recognized as (and this is 
important) STOICH.  The sensor is recognizing stoich, not
14.7.  The implied 14.7 is with the use of available 100% fuel. 

> and that is what i "should" see on WB and lambda 1.0?  

Depending on the WB controller in use, either it displays the
lambda figure or it converts it and displays AFR.  If it displays
lambda, yes, 1.0.  If converts to A/F it will read 14.7.

> so injector PW will change based upon what fuel per the 
> feedback from NB02 to ECU.

As the sensor is recognizing oxygen/stoich, vehicle won't be 
affected with the various concoctions in use.

> now in my tuning program i can adjust my "constant" for 
> stoich to a range.  it was set at 14.7.  should i set it 14.2 
> for 10% ethanol fuel which i run?  

If that is your choice.  As the exact AFR may vary, my 
choice is to tune with lambda.

GAS




More information about the Diy_efi mailing list