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title description published date tags editor dateCreated
Code_overview true 2020-04-08T02:09:35.609Z undefined 2020-01-06T01:54:26.709Z

Overview

A low level description of each code file and its purpose can be found in the Doxygen pages: https://speeduino.github.io/speeduino-doxygen/files.html

High level description of Speeduino control loop

The main loop in the speeduino.ino file runs continually and has 2 primary functions, determining the engine requirements and setting the ignition/injection schedules according to these requirements.

A high level description of the functions performed in the main loop is below:

  • Check whether there is a request in the serial buffer to be processed
  • See whether the engine is turning by looking at the last time a crank tooth was seen
  • Read values from all analog sensors (TPS, IAT, CLT, MAP, O2, Battery voltage). Not all sensors are read every loop as they do not change frequently enough to warrant this
  • The following functions only occur if the engine has 'sync':
    • Check whether the RPM is above or below the cranking threshold (Both fuel and ignition values are adjusted when the engine is cranking)
    • Run all corrections functions (See corrections.ino section below). The outcome of this is a % that the pulsewidth will be adjusted by (100% = no adjustment, 110% = 10% more fuel, 90% = 10% less fuel)
    • Lookup VE from the the main fuel table
    • Convert VE into a pulsewidth value in uS
    • Lookup the desired advance from the ignition table
    • Calculate the current crank angle
    • Calculate the crank angle that each injector should open at based on the current engine speed
    • Calculate the dwell angle based on the desired dwell time and current engine speed
    • Calculate the ignition start angle for each cylinder by subtracting the advance angle and the dwell angle from the TDC angle
    • Set a 'schedule' for each injector by converting the above calculated start angles into a number of uS in the future (Eg if injector should start opening at 45* ATDC and the crank angle is currently 10*BTDC, how long will it take to travel those 55*)
  • Perform the same schedule setting for each ignition output