AVR ignition

Discussion in 'The Projects Forum' started by anisbet, May 18, 2008.

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  1. anisbet

    Thread Starter New Member

    May 18, 2008
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    Hey I just started collecting parts for something similar.

    I am working with nissan on stuff and they use a optical trigger wheel in their distributors and cam angle sensors. They usally have 360 holes around the outer edge of wheel and then the number of cylinders for the number of holes around the inner ring. I will be hooking up both the output to interrupt lines on a atmega128 and using mosfets to fire coils in a wasted spark config. I will be able to cover the distributor with a cap machined from plastic or aluminum.
    I plan on having two lookup tables(maps) one used for advance and the other for coil dwell. I will use a GM map sensor for load data from the engine.


    I am going to try to use some IRF530's but may change to the bosch bip373 if I fry them.
    http://www.diyautotune.com/catalog/bosch-bip373-coil-driver-p-230.html


    -Avery
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    Sounds like an interesting project.

    We prefer you to start a new thread if you have a new topic, even if it's related to an existing thread. That way, everybody knows who and what they are answering.

    I did not see a question in your post, so I imagine we may hear from you again if problems arise.
     
  3. ratlifflj

    Member

    Nov 4, 2008
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    Hi,
    I was cruising the web looking for information on a project like this. I am currently in the process of building an ignition control module for both a three cylinder and a four cylinder engine and I am also using a atmega128. I was wondering if this project discussed here was completed. if so I would like to discuss some things. for instance, I am reading the signal from the cam sensor, I have converted it to a digital pulse and there are six periods for each revolution of the cam (3 per revolution of the crank, note: this is for 3 cylinder engine). one of the teeth is longer so I get five short pulses an one long. the long pulse tells me where top dead center is for the number 1 cylinder. i can detect this pulse, but I am having trouble getting the correct output based on this pulse. What I mean is that I want output to the 1st cylinder on this tooth. so I detect this tooth grab the index for it, calculate the index for the proceeding tooth (ie long_tooth_index-1) and then on the next cycle where the tooth_index = long_tooth_index-1 I want to count for a time period and then fire for a time period to an output. this delay is the degrees before top dead center. I can also do this but for some reason it doesnt stay consistent. I can provide more details if necessary.
    thanks
     
  4. ratlifflj

    Member

    Nov 4, 2008
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    also, I see that the first post here seems to be in response to something.
    what was the thread it was in response to so that I may check it out?
    thanks
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Try searching on "ignition". There are too many of these going.
     
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