Heating of sensors
The oxygen sensor heating is switched on by the ECU when the following conditions are met:
- the intake pressure is below a certain threshold, depending on the engine speed;
- speed below 135 km/h;
- after the engine has been running for a certain period of time, determined depending on the TDC of the engine cylinder pistons (if the accelerator pedal is not in the "idle" position) and the coolant temperature.
The oxygen sensor heating is switched off when the following conditions are met:
- the vehicle speed is higher than 140 km/h (reference value);
- high engine load.
Correction of the composition of the working mixture
Original of this article on the website RenaultBook
The value of parameter PR 138 "FUEL-AIR MIXTURE CORRECTION VALUE" read on the diagnostic tool is an average value entered by the ECU depending on the information about the composition of the working mixture transmitted by the oxygen sensor installed in front of the catalytic converter (the oxygen sensor analyzes the oxygen content in the exhaust gases).
Correction value for the midpoint 50% and for the extreme positions 0 and 100%:
- value below 50% lean mixture request;
- value above 50% request for mixture enrichment.
Start of regulation of the composition of the working mixture
1. Phase of "closed control loop".
Regulation of the working mixture composition begins some time after the engine is started if the coolant temperature is above 10°C (cars with manual transmission) and 25°C (cars with automatic transmission).
2. Phase "opening the control circuit".
When regulating the fuel mixture composition, the ECU does not take into account the value of the sensor signal voltage in the following cases:
- when you press the accelerator pedal all the way down;
- under significant loads and high crankshaft speed;
- when decelerating, if there is information about the accelerator pedal being released;
- if the oxygen sensor fails.