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: exhaust gas recirculation valve I Demand-driven oil pump with suction stage (V8) vane-type camshaft adjuster two-stage turbocharger (bi-turbo)