In order for the engine to run smoothly in the first minutes after starting, the idle speed stabilization valve opens the air channel for air to bypass the throttle, and the air-fuel ratio corrector increases the amount of fuel supplied for injection.
As the engine temperature rises, the idle speed control valve gradually closes the passage for additional air to bypass the throttle. At the same time, there is a gradual decrease in the amount of fuel sent to the injectors for subsequent injection.
When the engine is idling, to ensure its uniform operation and smooth fuel injection, air is admitted into the combustion chamber at the time of injection, providing a high degree of atomization of the injected fuel. Air enters the injectors through the intake valve on the cylinder head and then through a special air channel. The idle control valve provides additional air to bypass the throttle in the event of a low idle speed.
When the engine is running in the design operation mode and acceleration is performed (overclocking) all of these components fully meet the needs of the engine. No additional items are needed. Fuel supply is carried out depending on the position of the shut-off valve on the intake air volume flow meter. The desired ratio of air and fuel is adjusted automatically.
At full load on the engine, the throttle angle sensor tells the electronic control unit that the accelerator pedal is fully depressed. In response to this, the air-fuel ratio corrector receives an indication to increase the fuel supply.
When driving in the forced idle mode, the fuel supply is cut off if the vehicle is moving downhill and the driver does not press the accelerator pedal.
The adjustable catalyst can only work correctly when the value (lambda) is equal to 1, which corresponds to the ratio of fuel and air as 14.7:1. To ensure this, the KE-III-Jetronic system has a lambda value adjustment mechanism.
For this purpose, the lambda probe measures the oxygen content in the exhaust gases, thus generating an initial value that is taken into account when forming the air-fuel mixture. If the value obtained by the lambda probe does not correspond to the nominal value, then the control unit requires the air-fuel mixture corrector to make the appropriate corrections. Thus, the lambda regulation mechanism works flexibly, because only in the range of values (= 0.8-1.2 the catalyst is able to ensure the combustion of harmful substances.
The lambda probe is able to give the appropriate signal to the electronic control unit only when heated to a temperature of 350°C. For this reason, it has electric heating (see illustration 12.0).
Until the moment the lambda probe warms up, the electronic control unit uses the average lambda value in its calculations. The same thing happens when the engine is running at full load, and the electronic unit ignores the signals of the lambda probe.
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