tühikäigudüüs

A tühikäigudüüs, which translates to "idle jet" in English, is a crucial component found in carburetor systems of internal combustion engines. Its primary function is to deliver a small, precisely metered amount of fuel to the engine when it is operating at idle speed. This ensures that the engine can maintain a stable rotation without stalling, even when the throttle is completely closed.

The idle jet is typically a small brass nozzle with a very precise orifice. Fuel is drawn through this jet by the vacuum created in the carburetor's venturi when the engine is running. The amount of fuel delivered by the idle jet is critical for smooth idling. If the orifice is too small, the engine may run lean and stall. If it is too large, the engine may run rich, leading to poor fuel economy and increased emissions.

During idle operation, the throttle plate is nearly closed, significantly restricting airflow. The main jet, responsible for fuel delivery at higher engine speeds, is largely bypassed. The tühikäigudüüs is designed to provide the necessary fuel-air mixture for combustion under these low-speed, low-airflow conditions. In some carburetor designs, there may also be an idle mixture screw that allows for fine-tuning of the fuel-air ratio supplied by the idle circuit. Maintaining a properly functioning idle jet is essential for the overall drivability and performance of a carbureted engine.