Warm-up phase: the temperature sensor reports the gradual warming of the coolant to the control unit through changing resistance values.
Idle: The idle signal switch informs the control unit of this operating mode. The throttle position controller regulates the idle speed and compensates for the reduction in engine speed caused by the activation of powerful current consumers, the power steering fully turned to one side, the automatic transmission in the working position or the air conditioning on.
Normal operation: The control unit receives information about engine operation via speed pulses and resistance readings from the throttle potentiometer (throttle position). From this, the control unit draws conclusions about the engine load status and measures the required amount of fuel to the incoming air through the injection nozzle.
Lambda control: the fuel/air ratio 1=1 is taken into account when dosing the fuel. The constant change of rich and lean mixtures enables optimal operation of the catalytic converter.
Acceleration: Thanks to the signals from the potentiometer, the control unit recognizes a sharp press on the accelerator pedal as an acceleration process, as a result of which the mixture is immediately "enriched". Full load: in the full "gas" position or the control unit ensures enrichment of the combustible mixture in full load mode. Therefore, there is proportionally more fuel in the mixture. The potentiometer informs about the position of the throttle valve. However, when enriching the combustible mixture in full load mode, the signal from the lambda probe is ignored.
Forced idle mode (coasting): The Mono-Motronic injection system saves fuel and shuts off fuel supply as soon as the engine has reached operating temperature. The control unit recognizes this operating condition when the "accelerator" pedal is released (throttle potentiometer), messages from the coolant temperature sensor and engine speed above 1500-1900 rpm.
Engine speed limitation: if the maximum speed is exceeded, the control unit cuts off fuel access. Speed limitation cannot be achieved by turning off the ignition, since unburned fuel will end up in the catalytic converter.
Shown here is the injection nozzle (2) with the plug (1) still connected, removed from the socket (3) of the fuel mixture preparation unit. The fuel strainer is visible on the side of the valve.
Disassembled pressure regulator. The numbers indicate: 1 — cover; 2 - spring; 3 - membrane; 4 — supporting surface.
Operation in emergency situations: If the signal from one of the information providers does not arrive at all or has a meaningless value, the Mono-Motronic injection system still continues to operate normally. The control unit has so-called reserve values, which are already stored in the memory. Such a reserve value, of course, cannot take into account many operating conditions, but the car still remains mobile. The driver can recognize the absence of a signal from the sensor by insufficient power or poor starting properties.
A link to the original source is available on the website audimanual.ru