Lambda delay table and rate

Discussion and support for MoTeC's previous generation of entry level ECUs

Lambda delay table and rate

Postby LSR Racer on Fri Apr 20, 2018 11:20 am

What is a method that I may use to determine the lambda delay? I watched the webinar on how to setup closed loop wide band lambda control and I'm not clear on how to make the events happen that I need to then measure the O2 sensor response in i2.

Another question - I'm riding around, logging, then making changes to the fuel map and it's close enough that the bike works well enough. Should I load the lambda AIM table with all 0's so I'm tuning the map without the influence of the closed loop lambda control?

I can't get on a dyno yet.

Thanks
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Re: Lambda delay table and rate

Postby Stephen Dean on Mon Apr 23, 2018 11:17 am

The best method to determine Lambda Delay is to do a step test, and measure the resultant delay. In the M84, the step test is easiest done using an overall fuel trim applied a varying loads.

I would normally start at Idle, add a 10% trim (needs to to large to get an obvious change) and wait till the Lambda changes, wait for it to settle, and then remove the trim, again waiting for the Lambda to settle back at the new point. You will most likely have to pull the logging to do this testing as you can't pause the time graph. Measure the delay in both directions, and use the larger value obtained in the delay table.

Once this is done, do this change at higher engine speeds/load points to build the table. You should see a rapid reduction in the delay as you go up in load initially, and then the delay will tend to plateau over a certain point.
Stephen Dean
MoTeC Research Centre Melbourne, Australia
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Re: Lambda delay table and rate

Postby LSR Racer on Thu Apr 26, 2018 3:55 am

Thank you!
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