Carburetor system for multicylinder engine

Abstract

A carburetor system for us in a multicylinder engine comprises a carburetor having a main fuel-air mixture supply device to supply a mixture leaner than stoichiometric to at least one first cylinder and a corresponding number of second cylinder. A rich mixture supply device, integrated into the carburetor, has a rich mixture forming passage to make a mixture richer than stoichiometric. The main mixture supply device communicates with the first and second cylinders by a first passage, while the rich mixture forming passage with the second cylinder by a second passage. A first, second and third valves are provided in the first, second and rich mixture forming passages, respectively. These valves respectively are opened and closed by a first, second and third valve actuation devices, which are in turn regulated by an operation control device. Depending on the engine operating range and driving conditions, this carburetor system supplies a rich mixture to the second cylinder to raise the fuel-air ratio in it. By thus feeding both lean and rich mixtures to the engine, this system purifies its exhaust gases.

Dependencies are inferred from the claim text.