Open Issues ToDo
Q: Has anyone experienced problems with poor table lookup performance?
Bill, im very intrested in this problem, is this something you also see on the pre-compiled (recent) releases ? I know we have had some issues with different avr-gcc versions in the past, make sure you are using the recommended version (see WinAVR), but anyway thanks for the report i will look into this - DB
A guy here in Sweden has reported a similar problem but related to ignition. With a steep ignition map in the idle range he said that he got a strange spark behavior, he claimed a problem with the interpolation but never made a report that allowed us to recreate the problem. I suspect that this can be related. -Jörgen
Jorgen - we too saw the problem initially several months back while trying to use timing controlled idle. Bill
I have installed pre compiled firmware .53. The firmware has a problem interpolating in both x and y as can be seen by
http://www.lolachampcar.com/images/53%20map.pdf
http://www.lolachampcar.com/images/firm53%20rpm.pdf
http://www.lolachampcar.com/images/53%20map%20and%20rpm.pdf
http://www.lolachampcar.com/images/53%20VE%20Table.pdf
I have used unrealistic VE values to highlight the abnormality and to ease my understand of which cell values are being used in the averaging at which times.
When you are on cell, the index picks that cell and the next highest while the weighting favors the ohter direction. Change search_table in helpers.c as follows-
if (item <= tbl[i]) { // was just < which may be causing VE lookup problem
I have tested this and it fixes both RPM and MAP VE lookup problems (and probably timing and Lambda as well). We will be testing more on the dyno today.
An example of how CWL, CWH, AWEV, AWEV_Temp..., and AWC affect cranking and afterstart can be found at MembersPage/BillHart/CrankingAfterStart.
Recent Questions:
MembersPage/BillHart/ProblemHistory for older issues that have been resolved.
Projects Underway
MembersPage/BillHart/WinMobileLogger Win Mobile platform to Fat32 memory card logger. Looking for SIPR examples, if any, to ease the adding V3.3 query to Win Mobile code.
- [VR_Emulator] is a parallel port based Op-amp circuit that provides a plus or minus pulse about zero to emulate a VR sensor. You build the Basic routine to generate the crank (and cam)input wave form you need. Drop me a note if you need my QB code as a starter.
- we usually use stereo soundcard nowadays. It has many advantages, like processor overhead is small, amplitude can be varied, code is not hard to port between platforms, and it can even work without any executable (wav-s can be played with standard tools).
MembersPage/BillHart/LoggingDongle anyone interested in a small relatively inexpensive logging dongle?