HansB

I am looking into the possibility to build a cheap and compact unit to display the AFR using the stock lambda sensor. ( I was educated as a Electrcal Engineer in my youger years ). Somewhat as the LR unit, but then less bulky, and without the injector readout.

I found this table as the output from a 5 wire Bosch sensor,

The DIY-WB Controller
Vout Table for Gasoline
Vout Lambda AFR FAR
1.40 0.685 10.08 0.099
1.45 0.695 10.23 0.098
1.50 0.706 10.38 0.096
1.55 0.716 10.53 0.095
1.60 0.727 10.69 0.094
1.65 0.738 10.86 0.092
1.70 0.750 11.03 0.091
1.75 0.761 11.20 0.089
1.80 0.774 11.38 0.088
1.85 0.787 11.57 0.086
1.90 0.800 11.76 0.085
1.95 0.813 11.96 0.084
2.00 0.827 12.17 0.082
2.05 0.842 12.38 0.081
2.10 0.857 12.60 0.079
2.15 0.872 12.83 0.078
2.20 0.889 13.07 0.077
2.25 0.905 13.31 0.075
2.30 0.923 13.57 0.074
2.35 0.941 13.84 0.072
2.40 0.959 14.11 0.071
2.45 0.979 14.40 0.069
2.50 1.00 14.70 0.068
2.55 1.037 15.25 0.066
2.60 1.077 15.84 0.063
2.65 1.121 16.48 0.061
2.70 1.168 17.18 0.058
2.75 1.219 17.93 0.056
2.80 1.276 18.76 0.053
2.85 1.337 19.66 0.051
2.90 1.405 20.66 0.048


AFR = Air/Fuel Ratio
FAR = Fuel/Air Ratio

Can anybody confirm/deny that the Vout for the stock sensor is the same?

Thx, Hans

special tool

I can check it against my analog af display, but I can't garantee exactness. Will that help?

awilson40

It had to be different. On a stock sensor Lambda 1.0 (14.7 /1) is around .435 v out.

Edman951

Check out this site. he made one to fit his gauge cluster. It's pretty cool.
<a href="http://members.***.net/shokwave/airfuelmeter.htm" target="_blank">http://members.***.net/shokwave/airfuelmeter.htm</a>
<a href="http://members.***.net/shokwave/performance.htm" target="_blank">http://members.***.net/shokwave/performance.htm</a>

Does anybody know if you can plug up a 5 wire sensor in the exhaust and just read the voltage output. Then you just need to look up the voltage you get to a chart end you then know the exact a/f ratio you have.
This could be a cheap mans wideband sensor kit.

HansB

Yes, that would be roughly the layout I had in mind, preferably even half that size.

But the question remains: Is there somewhere a table translating the AFR to Vout on our sensor?

HansB

Edman951, as to your question
</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva"> Does anybody know if you can plug up a 5 wire sensor in the exhaust and just read the voltage output. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">I guess alas the answer is no.

Check this site: <a href="http://www.diy-wb.com/info.htm" target="_blank">www.diy-wb.com/info.htm</a>

HansB

oops

Bri Bro

The answer is no. The data above looks like a wideband (WB) O2 sensor, stock lambda sensor are narrow band (NB). THe wideband O2 sensor requires a special interface that requires a seperate circuit to drive them. THe WB sensor itself also runs around $150 plus the cost of the interface circuit, another $150 or so. The WB has a close to linear output were the NB has a sharp transistion at lamda=1.
<img src="http://boards.rennlist.com/upload/WBO2_d5.gif" alt=" - " />