Table of contents: Launch ↓ Warm-up ↓ Normal mode, acceleration and full… ↓ Fuel cut-off when coasting ↓
Launch
The vacuum created by the engine pistons lifts the air measuring plate. At the same time, the distributor piston opens the fuel supply to the injectors. When the starter is turned on, the cold start valve simultaneously injects additional fuel into the supply system, provided that the engine is cold. Only then does the control unit "allow" injection. The maximum injection duration depends on the temperature.
Warm-up
In order for the engine to run smoothly in the first minutes after starting, the idle speed stabilization control valve opens a channel that bypasses the throttle valve to allow additional air to flow. At the same time, the pressure regulator allows more fuel to pass through the valves. Large amounts of air and fuel provide increased speed during warming up with a richer mixture. During warming up, the control valve increasingly blocks the air flow. At the same time, the fuel supply is gradually reduced to normal. The pressure regulator reduces the amount of injected mixture.
For uniform idle speed and gradual acceleration when applying "gas" at low speeds, air bypasses each of the injectors into the combustion chamber. This ensures finer atomization of the fuel. Air passes through a branch pipe into the cylinder head and through a special air channel to the injectors. The control valve for stabilizing idle speed bypasses more air through the throttle valve if the speed falls below the nominal value.
Normal mode, acceleration and full load
No special devices are required to operate in these modes. The plate in the air quantity meter is lowered or raised, depending on the amount of incoming air. Accordingly, the fuel supply to the injectors changes: more air - more fuel, less air - less fuel. The optimal mixture ratio is set automatically.
Fuel cut-off when coasting
This mode is activated when the car is descending a mountain while simultaneously releasing the gas pedal.
[This publication is borrowed from the resource: AudiManual.ru]