What is the function of carburetor?
Carburetor is the core of fuel injection system, so its function is no doubt fuel injection. The fuel injection is divided into three main functions: atomization, air fuel ratio control and total amount control.
Now it has been mentioned that in the engine is ignited by air-fuel mixture, then how does air and fuel mix? This is fuel atomization. Air passes through the air passage to inhale the engine, and passes through a place called the throat. The throat capacity decreases and the air pressure increases. At this time, the nozzle injects fuel (gasoline or diesel) into the throat. Under the action of high-pressure and fast-flowing air, the fuel is blown into a mist and mixed with the air, which is sucked into the engine cylinder (the suction of the engine). The gas stroke is burned (ignition stroke), as shown in Figure 1.
2. Controlling air-fuel ratio
The air-fuel ratio is the ratio of air to fuel. If one volume of air is mixed with one volume of fuel, the air-fuel ratio is l:1. In theory, when the vehicle is running at a uniform speed, the resistance to be overcome is the smallest, and the space-time fuel ratio is 16:1, which is the best air-fuel ratio, known as the economic air-fuel ratio. Of course, at idle speed, the engine is also output with the minimum power. At this time, the output power of the engine can only overcome the resistance consumed by the engine itself. In theory, the air-fuel ratio is 14.66:1, but it is difficult to accurately meet this standard in actual use. In practice, it is usually between 15:1 and 16:1.
The work of controlling air-fuel ratio is also done by carburetor. The main equipment to control the air fuel ratio is the measuring hole, the main air measuring hole and the main oil measuring hole, as shown in Figure 2.
3. Controlling Total Amount
The total amount is well understood as the amount of mixture injected into the engine cylinder. When a car is running at a uniform speed, it needs very little mixture. When the car is accelerating or going up the hill, it must increase the power of the engine. If you want to increase power, you need to increase the amount of mixture injected into the engine, so that the engine can quickly output more power.
This total amount is controlled by the throttle. The throttle is connected to the throttle pedal through a connecting rod. When the driver pushes down the throttle pedal, the throttle opens at the corresponding angle so that the mixture flows into the engine cylinder through the opening of the throttle.