Patent ID: 6073604
Filing Date: 2000-06-13
Classification: F02B,Y02T

Abstract:
A combustion chamber structure of a gas engine, comprising:combustion chamber members installed in a cylinder head and formed with main combustion chambers and pre-combustion chambers communicating with the main combustion chambers;throat holes formed in the combustion chamber members to allow communication between the main combustion chambers and the pre-combustion chambers;throat hole valves to open and close the throat holes;fuel supply ports opening to the pre-combustion chambers to supply a gas fuel to the pre-combustion chambers;fuel supply valves to open and close the fuel supply ports; andsub-communication holes opening at wall surfaces of the throat holes situated in the main combustion chambers and at upper wall surfaces of the pre-combustion chambers to allow communication between the main combustion chambers and the pre-combustion chambers;wherein lower axes of the sub-communication holes opening into the main combustion chambers extend toward the centers of the throat holes, and upper axes of the sub-communication holes opening into the pre-combustion chambers extend offset from center axes of the pre-combustion chambers;whereby gaseous fuel in said pre-combustion chambers is sprayed, early in a compression stroke during which said throat hole valves block off said throat holes, into said main combustion chambers, wherein lean fuel-air mixture is produced, and when a pressure in said main combustion chambers has risen late in the compression stroke, air in said main combustion chambers is admitted through said sub-communication holes into upper areas in said pre-combustion chambers, wherein swirls are formed in said upper areas in said pre-combustion chambers to produce the lean fuel-air mixture in said upper areas in the pre-combustion chambers and at the same time to push downward said gaseous fuel to lower ares in said pre-combustion chambers, where very fuel-rich mixture is produced, so that combustion begins in a boundary layer between said lean fuel-air mixture and said very fuel-rich mixture, and subsequently, on opening said throat hole valves, said very fuel-rich mixture in said lower areas in said pre-combustion chambers is sprayed early and thoroughly into said main combustion chambers, with no unburned gaseous fuel remaining in said pre-combustion chambers.