20 12 new focus throttle is also called throttle.
We often say that the size of the "throttle" of a gasoline engine is actually achieved by controlling the intake air, and the speed is changed by controlling the intake air. Oil enters the cylinder with gas here, so all old gasoline engines have a carburetor. This device for controlling the intake air volume is called "throttle". When there is a carburetor, the throttle valve is a part of the carburetor. After changing to EFI, whether it is multi-point injection or single-point injection, it only has the function of atomizing gasoline with carburetor, and the basic principle of controlling the intake air to control the speed has not changed. At this point, the throttle is an independent component. In-cylinder direct injection is a revolutionary change, that is, controlling intake (with throttle) and also controlling intake.
When the carburetor is configured, the choke valve is a radiation auxiliary device. Because the normal mixed steam concentration is not easy to ignite when the cold car is started, a spring valve which can close the air inlet is set on the air inlet. When this valve is closed, it will start again. When it sucks air from the main air inlet of the carburetor, the resistance of the cylinder will increase, which will suck out more oil (of course, the main purpose is to increase the air flow at the oil injection port to achieve the effect of negative pressure to absorb most oil). If there is no carburetor structure, it is impossible to suck more oil from the injection hole when the main air passage is closed. Therefore, the "choke" mechanism is the exclusive configuration of carburetor.
Of course, increasing the intake concentration in the carburetor structure is helpful to start, and it is not only a choke mechanism, but also a bypass enrichment port, which can also start enrichment, and it is more effective and better controlled. At the same time, there is also a mechanism called acceleration pump, which can also achieve the effect of short-term concentration of mixed steam. It is equipped with an oil nozzle in the main air passage, which can spray oil mist to the main air passage when stepping on the accelerator. Because the action of this kind of fuel injector is started when the accelerator is slammed, you may often see that people who drive classic cars have a habit of stepping on a few feet of oil when the cold car starts, or even stepping on a few feet of oil when it has started. This is the habit of people affected by the configuration of science and technology.
On the other hand, even the carburetor structure, a large part is not equipped with "choke valve".
An EFI vehicle like Fox has no choke, because it can be used directly under "idle working condition", and the computer can directly distribute more fuel injection quantity to achieve the effect of thickening the mixed steam. Therefore, when the cold car starts, the idle speed of the Focus model will be as high as 1200 rpm or even higher, and then gradually decrease after the engine temperature comes up. This is a warm-up procedure, and it is also a cold car help start-up procedure.