Diaphragm carburetor
The diaphragm carburetor is a carburetor for internal combustion engines that works regardless of the position and even in the event of vibrations.
This is achieved by the fact that not a swimmer doses the amount of fuel in a float chamber , but a barometer that is connected on the one hand to the fluctuating negative pressure in the intake tract and on the other hand to the ambient air. The diaphragm of the barometer box actuates the valve that controls the flow of fuel from the tank to the carburetor (more precisely: the intake duct). In some types, the barometer box works together with a check valve in the tank cap as a diaphragm pump , sucks the gasoline into the carburetor and pumps it into the atomizer head in the intake duct. The strength of the fuel flow from the atomizer head is regulated by a nozzle needle: the more tightly the air flow is throttled (e.g. with a throttle valve), the lower the fuel flow into this air flow, and vice versa. Other types are equipped with an additional vacuum operated fuel pump. These do not have a nozzle needle, the membrane control only regulates the pressure at the main nozzle.
Diaphragm carburetors were first developed for aircraft that were used in aerobatics. Later they also found their way into vehicles that are operated with high lateral acceleration, such as racing cars or teams. And they are also used in handheld tools that have to work in any position, such as chainsaws .
Diaphragm carburetors can be equipped with either a throttle valve or a flat slide valve. The importance of membrane carburetors has decreased as the prices for injection systems have fallen. The carburettors made by Tillotson and Walbro are widely used in karting .
literature
- Gert Hack: make cars faster. 11th edition, Motorbuchverlag, Stuttgart, 1980, ISBN 3-87943-374-7 .
- Hans Jörg Leyhausen: The master craftsman's examination in the automotive trade part 1. 12 edition, Vogel Buchverlag, Würzburg, 1991, ISBN 3-8023-0857-3 .