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Determine injection timing in real time from oem ecu

Practical Diesel Tuning

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I introduce myself my name is Romain I am from France and I am a preparer specializing in HDI diesel (common rail) as well as TDI (pump injector).

I am preparing a 2l 4 cylinder 8 valve common rail engine, dragging and running within 10 seconds at 1/4 mile with around 500 hp, base horsepower is 90 hp.

I use the original ECU which is very old (2001), so I bought an AEM carbon CD7 logger dashboard in order to have more control and values ​​in order to better adjust my configuration.

I am asking to try to create a mathematical channel in order to determine the injection advance to be able to coordinate the injection correctly because I have larger injector noses, a very large high pressure pump as well as all the mods of support for 700/800 hp: the injection time was therefore reduced, the rail pressure increased so synchronization is more than desirable.

I have the signal from the injector (by the ground) that I clocked in duty cycle on the dashboard, the top dead center sensor (crankshaft sensor) in hertz (engine speed) but also in voltage, as well as the sensor camshaft.

The angular reference and speed of rotation measurement is carried out by a crankshaft sensor (TDC) fixed on the clutch housing and placed opposite a crown of 58 teeth (60-2) mounted on the engine flywheel.

This sensor consists of a permanent magnet and a winding which is the seat of an electromotive force induced by variation of flux, variation caused by the passage of each of the teeth of the crown under the sensor.

The frequency at which the impulses caused by the 58 teeth of the crown gear occur represents the speed of rotation of the motor.

The zero crossing of the induced voltage due to the two false teeth represents the reference mark. The descending flank of the first alternation that appears is located at 114 ° before TDC.

The camshaft sensor The computer needs a cylinder reference in order to be able to phase the control of the injectors in sequential mode (cylinder by cylinder in the order 1-3-4-2).

To do this, it recognizes the top dead center in compression of each cylinder using the information provided by this sensor.

Hall effect type, it is installed on the camshaft cover facing a target wheel fixed at the end of the camshaft.

- The target is facing the sensor: low state, output signal equal to 0 volts

- The target is not facing the sensor: high state, output signal equal to 5 volts.

On starting, the computer checks that, over two crankshaft revolutions, the reference sensor signal has changed level at least once. Then the computer checks whether the square waves of the reference sensor signal are correctly positioned in relation to the signal from the engine speed sensor.

At the first TDC the front of the target is in the high state (5 volts): in this case it is the TDC compression of cylinder n ° 1.

The next three TDCs will have a target signal low (0 volts).

Can we find a formula that I will use with AEM DATA to use these inputs to determine the injection timing in real time?

Attached Files

Question what the max sample rate of this display. Simple calculation 6000Rpm and a sample rate of 1000Hz only gives 10 sample per rotation.. Not very accurate I would say.

Je l'ai cadencé à son maximum soit 1khz donc 1000 hz et je prendrai actuellement 5500 rpm et au maximum 6000 rpm, pensez vous que ce n'est pas faisable ?

6000 ÷ 60 =100

100 times in 1 seconde = 0.01

I need to know just for a single cylinder with the information of a single injector, because it is an original ecu therefore which controls the 4 cylinders in the same way...

1000hz = 0,001

Best Way to obtain this information is by using an Oscilloscope, one channel for the Crank trigger, and the second on the injector.

You can also setup a good DAQ system such as the PLEX PCA-2000.

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