Starting: The vacuum created by the engine's intake pistons lifts the shut-off valve in the air flow meter. This causes the distributor piston to allow fuel to flow to the injection nozzles. When the starter is running, the starting fuel valve supplies additional fuel to the intake system. The control unit allows this injection.
Engine warm-up phase: To ensure that the engine runs smoothly during the first minutes after starting, the idle speed stabilization valve opens a channel through which intake air can flow bypassing the throttle valve.
Additionally, the pressure regulator lets in more fuel through the injectors. The increased air and fuel supply allows for higher engine speeds during the warm-up phase. As the engine temperature increases, the distribution valve increasingly closes off the air supply and the pressure regulator reduces the amount of fuel injected.
Idle: To achieve a uniform engine speed in idle mode, air enters the combustion chamber around each injection nozzle in the lower speed range. The air flows to the injection nozzles through a connecting nipple and a special air channel. The distribution valve for speed stabilization allows more intake air to enter bypassing the throttle valve if the speed drops below the standard value.
Normal operation and acceleration of the car do not require any special devices. The valve shutter in the air flow meter rises or falls depending on the amount of air received. Accordingly, the supply of fuel to the injection nozzles changes: a lot of air - a lot of fuel, little air - little fuel. Thus, the most favorable ratio for the combustion process is established completely automatically.
Full load: The throttle position sensor signals the control unit when the accelerator pedal is fully depressed that maximum power is now required from the engine. This gives the pressure regulator the command to supply slightly more fuel to the injection nozzles than usual.
Fuel cut-off in forced idle mode: The fuel cut-off function in forced idle mode turns off the fuel supply if the vehicle is going downhill and the accelerator pedal is not pressed.
(The original version of the article is posted on the website: «audimanual.ru»)