Concept of throttle valve

Choke valve is a part of carburetor of gasoline engine. Generally, the operation knob installed on the instrument panel is used to operate at the air inlet of the carburetor (the knob is generally marked as follows). Its function is to properly close part of the air intake when the engine is cold-started, increase the gasoline concentration of the mixed gas entering the cylinder and improve the starting performance of the engine. After the engine is running normally, the choke valve should be fully opened, otherwise the engine will not run normally and the fuel consumption will be too high because the mixture is too thick. The EFI engine is automatically controlled without manual operation. Audi 100 automobile engine works for a long time, and its cold start performance may not be very good. When starting the engine, the control knob can be pulled out by 2/3, and then slowly pushed in when the engine temperature reaches 50 degrees. When the engine is running normally, you should keep the choke fully open.

When the engine is started, the driver pulls out the choke button on the dashboard and pulls the cable to close the choke, so that the carburetor can supply thick mixture and the engine can be started easily. After starting, the driver should push the choke back to a position close to full opening. At the same time, slightly open the throttle with the hand throttle to increase the engine speed and shorten the warm-up time, and then push back the choke button completely after the engine gets hot.

Choke button, commonly known as "throttle", is a device to control the opening and closing degree of carburetor choke, which is arranged under the dashboard in the cab.