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Thread: Speeduino 2T EFI Project

  1. #241
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    20th January 2010 - 14:41
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    How quickly does the exhaust gas temp change with different running conditions Rob.
    I guess judging by water injection falure, its to slow to be useful as a calibration?



    Kinky is using a feather. Perverted is using the whole chicken

  2. #242
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    18th May 2007 - 20:23
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    Quote Originally Posted by husaberg View Post
    How quickly does the exhaust gas temp change with different running conditions?
    I have not done much work with EGT for myself but what I have seen with other bikes on the dyno the EGT seems as responsive as my O2 sensor. In other words, pretty good.


  3. #243
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    .
    Someone was asking about RPM and TPS spacing.

    The steps between RPM and TPS points does not have to be even. The trick is to position them so that the fuel "Load" steps between cells is smooth as possible, no big jumps.

    Typically the RPM steps follow the Torque curve and some of the RPM steps are bunched together in the rpm area where the torque curve is steepest as the motor is getting on the pipe. The idea is to keep the increasing fuel steps as even as possible as the RPM changes.

    Click image for larger version. 

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    The graph is a typical carburetor flow curve. I tested my ball valve inlet and got the green line. 50% of air flow is typically at 25% throttle open. So at least half the fuel steps need to be below the 25% throttle line to get the increasing fuel demand steps due to the steadily increasing air flow in as even as steps as possible.

    The point is RPM and TPS steps can be uneven, its the steps between Fuel load cells that need to be as even as possible.


  4. #244
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    Quote Originally Posted by DaveyB
    TZ, when looking at your VE table, it looks like you've only allocated 6 columns from 3000 to 7200 rpm for the crankcase pressure differential measurement, whilst giving 10 columns to Alpha N from 7800 to 13500 rpm? I thought that the area (in rpm) below where the pipe starts working would require finer control and thus more columns. On a separate note are you running the engine with premix or oil pump?
    Premix. 20:1.

    No, the area below (and above) the transition area where the pipe starts to work does not need as many columns as the transition area itself.

    I have abandoned the VE map approach and for now are concentrating on Alpha-N multiplied by the MAP/Baro ratio.

    Alpha-N is great for everywhere the airflow is consistent. So Alpha-N is good for everywhere that is not on the pipe and every where on the pipe and above 50% TP throttle position. There is only a smaller area where Alpha-N does not work well and that is in the area where you could be on the pipe and less than 50% TP. That is because air flow here is variable due to inconsistent pipe action.

    Currently my crankcase PseudoMAP outputs a MAP value equal to the Baro value in the areas where airflow is going to be consistent. So the Alpha-N map here is multiplied by the ratio of 1:1 i.e., Alpha-N * 1.

    And in the area where the engine should be on the pipe but the TPS is less than 50% the PseudoMAP outputs three times the Delta crankcase pressure. So in the variable air flow area the Alpha-N map is multiplied by the ratio of PseudoMAP to Baro pressure. i.e., Alpha-N * (PseudoMAP/Baro).

    Anyway this is the current approach I am exploring, hopefully find out soon how well this concept works.

    Click image for larger version. 

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  5. #245
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    20th January 2010 - 14:41
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    We can only imagine a bunch of Austrians are feverishly looking into it now Rob.



    Kinky is using a feather. Perverted is using the whole chicken

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