3.2L Porsche O2 Sensor Influence

  This is the engine emulator for the 3.2L Porsche that I made myself. I use this to test a BOSCH DME for 3.2L on a tabletop.



  In a 3.2L Porsche DME, I tested how much influence the O2 sensor output has on fuel injection volume.




  The high yellow line indicates that the injector is closed. The lower part is the state that the injector is open.
To simulate complete combustion, I prepared 0 V and 0.9 V signals for the same period as a proxy for the O2 sensor output.
The fuel injection time is 2.255ms.
  I entered 0V as a condition where the mixing ratio is too lean.
Fuel injection time has been increased to 2.495 ms. As a percentage, it's +10.6%.



  As the mixing ratio is too rich, I entered 0.9V as the mix ratio was too rich. Fuel injection time has been reduced to 1.835 ms. As a percentage, it's -18.6%.

The influence of the O2 sensor on fuel injection volume was greater than expected. We do not want to leave the terminals of the O2 sensor in a half-hearted state.