twin-choke downdraught carburetor Possible demonstrations: throttle butterflies open simultaneously function of choke butterflies, throttle butterflies, float with valve needle, pull-down device, accelerator pump and idle- speed stop description ordernumber 1029 see also: Common-rail injection Mercedes-Benz A Class diesel engine with common rail technique two-stage twin-choke downdraught carburetor 4A1 air-mass sensor with hot film