Constant pressure carburettors

US4420439A · kind A · utility

Assignee

• Bosch & Pierburg System oHG · DE

Inventors

• Gunter Hartel · Neuss, DE
• Armin Schurfeld · Meerbusch, DE
• Anwar Abidin · Leonberg, DE

Key dates

• Filing date: Jan 29, 1982
• Grant date: Dec 13, 1983
• Expiry date: Jan 29, 2002

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S261/74
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A downdraught carburettor of the constant pressure type has a mixing chamber 2 with an operator-controlled throttle valve 3 at its downstream end and a choke valve 10, which is operated by a diaphragm box 20 in dependence upon the pressure in the mixing chamber 2, at its upstream end. Fuel is supplied to the mixing chamber from an annular duct 5 through ports 6 to the wall of the mixing chamber down which the fuel flows in the form of a thin film. The film is evaporated to form the mixture by a heating jacket 16 which surrounds the mixing chamber 2 and is heated by engine cooling water or exhaust gases. In order to prevent the film of fuel from being broken up before it has been heated and evaporated, which tends to happen owing to turbulence in the air stream caused by the choke valve 10, an inner tube 11 is provided. The choke valve 10 is situated in the upstream end of the inner tube 11 so that the fuel film is screened by the tube 11 from any turbulence caused by the valve 10. Air flow to draw fuel from the ports 6 and build up the film on the wall of the mixing chamber takes place through narrow annular ducts 12 between the tube 11 and the surrounding mixing chamber wall, thes…