Reading lambda values higher than 10

Support forum for the Lambda Shield designed to connect Bosch LSU 4.9 wideband oxygen sensors to Arduino projects.
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labrat
Posts: 2
Joined: 08 Oct 2023 06:26

Reading lambda values higher than 10

Post by labrat » 08 Oct 2023 10:10

I have a diesel engine and would like to be able to read lambda values at idle and cruise, which are leaner than the arduino code is programmed to support in the lookup table. Is there a more detailed lookup table available or will this require the values to be calculated on the fly?
I can't seem to find a formula that is used to convert the pump current to a lambda value using the amplification factor v=17.

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Christian_Bylund
Posts: 259
Joined: 07 Mar 2015 18:09

Re: Reading lambda values higher than 10

Post by Christian_Bylund » 08 Oct 2023 12:41

labrat wrote:
08 Oct 2023 10:10
I have a diesel engine and would like to be able to read lambda values at idle and cruise, which are leaner than the arduino code is programmed to support in the lookup table. Is there a more detailed lookup table available or will this require the values to be calculated on the fly?
I can't seem to find a formula that is used to convert the pump current to a lambda value using the amplification factor v=17.
Hello Labrat,

Using amplification factor V=17 you can measure as lean as lambda 0.75. For Diesel applications we need to use the amplification factor V=8 allowing to measure as lean as lambda 0.65. See this post.

Hope it helps.
Best Regards,
Christian Bylund
Bylund Automotive AB

labrat
Posts: 2
Joined: 08 Oct 2023 06:26

Re: Reading lambda values higher than 10

Post by labrat » 08 Oct 2023 21:20

Sorry, either I don't understand or I haven't explained it well enough. I don't need it to read richer readings, i'd like it to read leaner. I'd like to read Lambda numbers that are higher than 10 or an AFR of over 200.
The current lookup table stops at 10.119 and i'd like to calculate all the lambda numbers for the ADC conversion for a lambda of up to 15 or even 20. On idle, cruise or deceleration it shows an o2 saturation from the sensor but because the fuel mixture is so lean it doesn't show the lambda or AFR readings when the ADC is more than 791.

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