Diaphragm-type carburettor with mixture enrichment when starting

摘要

A description is given of a diaphragm-type carburettor with a device for enriching the air/fuel mixture with fuel during the starting of the internal combustion engine. In this diaphragm-type carburettor, the diaphragm chamber, which is normally open to atmosphere, is connected to a pulsed-pressure source, more particularly via a pressure exchanger which converts the pressure pulses from the pulsed-pressure source into a single pressure surge to open the fuel inlet valve. The diaphragm chamber is connected to atmosphere via an exhaust restrictor which relieves the pressure produced in the chamber by the pressure surge in a predetermined time. It is expedient for the cross-section of flow of the exhaust restrictor to be controllable as a function of the outside temperature. The connection of the diaphragm chamber to atmosphere, which is open during normal carburettor operation, is closed during starting by a gate valve which can be moved into its closed position by means of a manually operated actuating device and moves into its open position again when the throttle valve is actuated. The mixture enrichment device described replaces the conventional choke. <IMAGE>