DE2648257

A carburation device has auxiliary throttle means and a main throttle. The auxiliary throttle means opens automatically in proportion to the increase in the flow rate of air and actuates proportioning means metering the flow rate of fuel drawn into the intake pipe, downstream of the main throttle via a passage. The passage includes a chamber which is kept at a pressure substantially equal to the pressure in the portion of the intake pipe between the throttle means by a bypass passage connecting said portion and chamber, having means which are sensitive to at least one engine operating parameter and which, in operation, adjust a control cross-sectional area in the passage means between the chamber and the intake pipe.