Results 1 to 3 of 3

Thread: UDS Protocol - Long term adaptation of mixture formation not available

  1. #1
    Verified VCDS User
    Join Date
    Nov 2019
    Location
    Australia
    Posts
    2
    Post Thanks / Like

    UDS Protocol - Long term adaptation of mixture formation not available

    I got a Q7 from 2011 that runs on UDS protocol. I'm looking to read out long term and short term fuel trim but the following three option are not (!) available to me under advanced measuring values.

    IDE00597 - Long term adaptation of mixture formation bank 1
    IDE00604 - Short term adaptation of mixture formation bank 1
    IDE01869 - Long-term fuel trim bank 1 at idle

    Any help would be much appreciated.



    Code:
    -------------------------------------------------------------------------------
    Address 01: Engine (J623-CJGA)       Labels:. 059-907-401-V2.clb
       Part No SW: 4L1 910 401 H    HW: 4L0 907 401 C
       Component: 3.0TDI EDC17  X37 0003  
       Revision: 53X37---    Serial number:               
       Coding: 2A2A4012A52701020000
       Shop #: WSC 31414 790 00001
       ASAM Dataset: EV_ECM30TDI0114L1910401H 001008
       ROD: EV_ECM30TDI0114L1910401H.rod
       VCID: 2809F8A4E2733C77A17-807C
    Last edited by dynamike; 12-02-2019 at 05:15 AM.

  2. #2
    Benevolent Dictator Uwe's Avatar
    Join Date
    Jan 2014
    Location
    Earth
    Posts
    26,463
    Post Thanks / Like
    Blog Entries
    1
    Uhm... That's a diesel. The concept of "fuel trim" doesn't really apply to them.

    Gasoline engines control power by controlling the airflow. The engine management then supplies an appropriate amount of fuel, with a feedback loop that "trims" the amount of fuel injected to keep the mixture stoichiometric. Bottom line: The pedal controls the throttle, which controls the amount of air the engine can ingest.

    Diesels control power by controlling fuel flow. The pedal controls the amount of fuel injected. In days gone by, diesels just allowed air to flow freely and ran quite lean at partial loads. However, that produced a lot of NOx emissions, which isn't acceptable anymore. Now you can't just restrict the airflow to a diesel because that would reduce the effective compression ratio, and you'd give up the efficiency, and you might not generate enough heat on the compression stroke to ignite the fuel. So what they do now is to mix incoming air with recirculated exhaust gasses in an attempt to keep the mixture in a range where it will neither produce soot or excessive amounts of NOx, but in the end, they still control power by more-or-less directly controlling fuel flow, so the concept of "fuel trim" simply doesn't apply.

    -Uwe-
    The engineering problems are likely insurmountable. It would be like proposing to land a rocket booster section on a barge floating in the middle of the ocean.

  3. #3
    Verified VCDS User
    Join Date
    Nov 2019
    Location
    Australia
    Posts
    2
    Post Thanks / Like
    Thanks Uwe for taking the time to explain in such detail. Much appreciated. All my acquired knowledge evolves around petrol engine.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •