The reason why the simple carburetor can't meet the requirements of the ideal carburetor is discussed with the formula.

The characteristic of an ideal carburetor is the relationship between the composition of mixed gas and the load (or charging flow) under the condition of satisfying the best performance. That is, when the throttle valve is fully opened, the cylinder should be provided with an appropriately rich mixture.

A/F= 12~ 14. The gasoline engine should have the best economy when it is running at medium load, that is, when the throttle valve is partially opened, and it is suitable for using a thinner mixture, with a/f of17; When idling, the throttle valve is almost completely closed to offset the influence of exhaust gas on fresh charge.

Ring, in order to ensure a stable speed, need to provide a more concentrated mixture, A/F= 10~ 12.4.

When using simple carburetor, A/F=? = √ Δ?

√? , air-fuel ratio with throat vacuum δ?

The above changes are just

Δ

It is a simple carburetor function. In the formula, can you think like this? 、? 、? 、? 、? 、? Basically unchanged. When δ? & lt time and combustion

Oil does not flow out of the nozzle; When δ?

When it is a little bigger, the fuel is sucked out, but √ δ?

Maximum, minimum air-fuel ratio, with

Do you have Delta? Increase, its √ δ?

The value drops rapidly and tends to 1.

Δ

Δ

A/F with δ? The curve changes as shown in the figure when it increases and thickens. Therefore, the characteristics of a simple carburetor are quite different from those of an ideal carburetor. If the engine uses a simple carburetor and works at idle speed and light load, the mixture is too thin, and the mixture is too thick at heavy load, which can not meet the requirements.