Hi,

I am looking for information about the injection regulation and especially the link between the oxygen sensor signal and the injection timing.

I know how the sensor works in terms of electronics, signal response,... I think I have understood that most ECU control fuel/ air ratio in closed loop through a PID regulation scheme but:

Why does this regulation lead to a variating ratio with a specific frequency, which seems to be constant and about 1Hz?

I observed this by looking at my probe signal over time on my Alfa 147 (motronic ME 7.3.4) and I though that the ECU Could follow a ratio of 1 with a faster response, so with a higher frequency?

What do you guys think?

Steph