Idle speed is the most commonly used engine operating condition, which is used in the process of engine hot start and non-stop stop. It is of great significance to the driving performance of the car, especially in the city, and the idling condition often determines the fuel consumption and pollution level of the car.
The idling speed of the engine is generally only 600-800 rpm, and the throttle valve is close to closed. The throat vacuum generated by such a speed cannot smoothly suck the gasoline out of the float chamber, but the vacuum behind the throttle valve is very high. Therefore, it is only necessary to set up another idle speed oil passage on the basis of the simple carburetor, and the nozzle hole is set after the throttle valve, and the problem is solved.
Since idling requires less and richer mixture, it is more sensitive to engine operating conditions. To achieve an idling state that requires both stability and minimum speed, it is necessary to adjust the fuel quantity control and the minimum throttle opening. The current carburetor idle speed device has two adjustment screws, which adjust the amount of oil and the opening of the throttle valve respectively. At the same time, in order to prevent the car from turning off the ignition switch while the engine is still running, there is also an idle solenoid valve in the idle oil passage of the carburetor, which is specially responsible for opening and closing the idle oil passage to ensure that the engine can be quickly turned off.