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What happens out of table space


dynoiasi

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Hello,

 

I'm sorry if the answer is already written in the help file or discussed on the forums before, but somehow I have not yet stumbled across the information. What happens when the input goes out of specified table bounds? Does the calculated output stay on the last prescribed value or is the output value calculated by extrapolating the gradient between the last 2 points? If we look at the example 2D table below, suppose the RPM goes to 400 which is outside the specified values in the table. What will the calculated enrichment output be in this case? 80  or 70? I would suppose the output will be 80 by extrapolation but I just want to make sure. Thank you!

 

                                      100RPM   200RPM  300RPM

enrichment whatever  50              60           70

 

 

Best regards,

Florin

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if a value goes outside of a table the table output is the value in the cell on that edge (e.g. if you go off the right hand end it will update as you move up and down to the appropriate cell on the right hand end of the table. Another example would be if you go off the bottom right corner (off of both axes) it will take the bottom right most cell. Tables do not extrapolate outside of their bounds.

In your example the output would be 70 for any engine speed greater than or equal to 300rpm.

Linear calibrations do extrapolate linearly outside of their two specified points.

 

 

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Thank you for the clarification! I'm really glad I asked this question because I somehow assumed that the output trend will continue by extrapolation because this seemed like the safer thing to do in the fuel table. On the other hand, it might not be so safe in the ignition table where you would increase timing towards higher rpm's if the table was "smaller" then the RPM... I guess I'll have to add another line to catch the boost cut value inside the table if the fuel does not extrapolate :D

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