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so i have this data frame comming from OBD2 : 

    Time    Engine RPM [RPM]    Vehicle Speed Sensor [km/h]     Air Flow Rate from Mass Flow Sensor [g/s]   pke     fuelflow    fuelcons
0   2020-06-01 06:58:41.245     0.0     0.0     0.88    0.000000    2.451724    0.000000
1   2020-06-01 06:58:42.026     0.0     0.0     0.88    0.000000    2.451724    0.000000
2   2020-06-01 06:58:43.045     0.0     0.0     0.88    0.000000    2.451724    0.000000
3   2020-06-01 06:58:44.035     180.0   0.0     12.02   0.000000    2.451724    0.000000
4   2020-06-01 06:58:45.085     1010.0  0.0     16.91   0.000000    2.451724    0.000000
5   2020-06-01 06:58:46.047     925.0   0.0     16.30   0.000000    2.451724    0.000000
6   2020-06-01 06:58:47.005     904.0   0.0     15.27   0.000000    2.451724    0.000000
7   2020-06-01 06:58:48.087     883.0   0.0     14.58   0.000000    2.451724    0.000000
8   2020-06-01 06:58:49.045     896.0   0.0     14.72   0.000000    2.451724    0.000000
9   2020-06-01 06:58:50.035     948.0   0.0     15.72   0.000000    2.451724    0.000000
10  2020-06-01 06:58:51.026     927.0   0.0     15.49   0.000000    2.451724    0.000000
11  2020-06-01 06:58:52.015     961.0   0.0     15.72   0.000000    2.451724    0.000000
12  2020-06-01 06:58:53.065     939.0   1.0     16.02   0.009643    2.451724    5.524138
13  2020-06-01 06:58:54.025     984.0   2.0     15.94   0.028930    2.451724    2.748276
14  2020-06-01 06:58:55.046     944.0   1.0     17.02   -0.028930   2.451724    5.868966
15  2020-06-01 06:58:56.035     952.0   1.0     16.49   0.000000    2.451724    5.686207
16  2020-06-01 06:58:57.085     952.0   1.0     16.52   0.000000    2.451724    5.696552
17  2020-06-01 06:58:58.046     956.0   1.0     16.49   0.000000    2.451724    5.686207
18  2020-06-01 06:58:59.005     934.0   1.0     16.02   0.000000    2.451724    5.524138
19  2020-06-01 06:59:00.085     981.0   1.0     16.83   0.000000    2.451724    5.803448
20  2020-06-01 06:59:01.076     940.0   1.0     16.08   0.000000    2.451724    5.544828
21  2020-06-01 06:59:02.065     915.0   1.0     15.69   0.000000    2.451724    5.410345
22  2020-06-01 06:59:03.085     909.0   3.0     15.63   0.077147    2.451724    1.796552
23  2020-06-01 06:59:04.076     1015.0  6.0     15.47   0.260370    2.451724    0.889080
24  2020-06-01 06:59:05.005     1377.0  9.0     19.77   0.433950    2.451724    0.757471

i want to detect engine braking event from this data. i really didnt try any thing? any help ?

أيمن تليلي
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  • Based on what I'm seeing it would be very hard to detect engine braking as there is no raw engine rpm. You have a header for it but I see no RPM as in 1800 RPM vs 1500 RPM – Pittsie Jun 02 '20 at 13:22
  • i'm showing only the first 24 column, the max value in my dataset is 3000 rpm,is there any rules or method to detect engine braking for diesel engine ? – أيمن تليلي Jun 02 '20 at 13:38
  • Not that I know of but an If statement should do. Not sure how your motor is set up but if you can find the drop in RPM when on the brake – Pittsie Jun 02 '20 at 13:48
  • i got an idea , i can make a sliding window to detect the drop in rpm using the standard deviation .. the problem here is how to set the threshold of std and the window slide .. – أيمن تليلي Jun 02 '20 at 14:27

1 Answers1

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If fuel flow <= 0 then engine braking.

Damon Earl
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  • that works only in gasoline engine, actually this data is from diesel engine – أيمن تليلي Jun 03 '20 at 10:15
  • Well you can assume even in diesel engines it would be no fuel flow while engine braking, it depends on how they braking the engine. If using full exhaust block off, you'll see little to no air flow on the MAF, if they're are using any of the other known methods (partial exhaust block off or adjustable turbines) that's not enough data. – Damon Earl Jun 04 '20 at 04:20