|
Title: How does the ECU read e.g. ignition maps? Post by: Beaviz on April 10, 2014, 02:56:16 AM I guess that this is common knowledge for most people here, but I have not been able to find the answer anywhere, so here goes.
I am wondering how the algorithm for e.g. the igintion maps works. An example might explain my question better: KFZW with made up values for simplicity (i know it is 0.75 increments IRL): ....... 5500.0 | 6000.0 150 | 20.00 | 25.00 170 | 10.00 | 15.00 190 | 00.00 | 05.00 An example could be actual load being 160% and the RPM 5500. Would the ECU interpolate the value, so it would read 15? If yes, then I guess that it would also apply to the RPM axis. E.g. load = 160% and RPM 5750 (interpolation between 15.00 and 20.00) would equal 17.50? And anything over 190% would just use the values from the last row? Title: Re: How does the ECU read e.g. ignition maps? Post by: panos1975 on April 10, 2014, 05:36:28 AM I think the ecu uses the last row value for every higher value over the last axis data point
Title: Re: How does the ECU read e.g. ignition maps? Post by: fknbrkn on April 10, 2014, 07:45:06 AM I guess that this is common knowledge for most people here, but I have not been able to find the answer anywhere, so here goes. I am wondering how the algorithm for e.g. the igintion maps works. An example might explain my question better: KFZW with made up values for simplicity (i know it is 0.75 increments IRL): ....... 5500.0 | 6000.0 150 | 20.00 | 25.00 170 | 10.00 | 15.00 190 | 00.00 | 05.00 An example could be actual load being 160% and the RPM 5500. Would the ECU interpolate the value, so it would read 15? If yes, then I guess that it would also apply to the RPM axis. E.g. load = 160% and RPM 5750 (interpolation between 15.00 and 20.00) would equal 17.50? And anything over 190% would just use the values from the last row? dont think that it uses interpolate algorithm because ecu needs to calc values from thousands maps at real time.. its a very high cpu load i think it uses last reaching value from table so at 150-169 load from your example you have 20 deg (5500) and only on 170 it switches to 10 and when load are decreasing you have a 10 deg from 170 to 151 thats why stock maps are so detailed but as i said before - its only my opinion, am wondering if someone can answer exactly how it works anything higher than map axis point uses last value Title: Re: How does the ECU read e.g. ignition maps? Post by: elRey on April 10, 2014, 07:52:39 AM log zw_local and find out for sure.
Title: Re: How does the ECU read e.g. ignition maps? Post by: phila_dot on April 10, 2014, 08:15:28 AM Linear interpolation of the row
Title: Re: How does the ECU read e.g. ignition maps? Post by: nyet on April 10, 2014, 09:40:03 AM Linear interpolation of the row This, plus no extrapolation past the end. Title: Re: How does the ECU read e.g. ignition maps? Post by: phila_dot on April 10, 2014, 10:01:26 AM log zw_local and find out for sure. zw_local isn't written to RAM and cannot be logged. The first variable available for logging is zwnws. Title: Re: How does the ECU read e.g. ignition maps? Post by: gremlin on April 10, 2014, 10:32:15 AM zw_local isn't written to RAM and cannot be logged. The first variable available for logging is zwnws. As example. Below is a list of RAM ZW-parameters availiable in ME7.5 ECU |