GAS INTERNAL COMBUSTION ENGINE WITH PRE-CHAMBER FUEL SUPPLY DEVICE

An object is to provide a precombustion-chamber fuel supply device for a precombustion-chamber gas engine having high reliability and low operation cost by reducing outflow of fuel gas to the precombustion chamber in the exhaust stroke and dispersion of the amount of fuel gas supplied to the cylinders, which makes it possible to cut fuel consumption and to achieve stable combustion. A gas internal combustion engine of a Miller-cycle type includes: a main chamber 60 defined between a piston and a cylinder head 1; a precombustion chamber 4 which communicates with the main chamber 60 via a nozzle 3 and in which fuel gas is combusted by a spark plug 10; a gas supply channel to precombustion chamber 14 for supplying the fuel gas to the precombustion chamber 4; and a check valve 6 disposed in the gas supply channel to precombustion chamber 14 and configured to open due to a pressure decrease in the precombustion chamber 4 at a BDC of an intake stroke of a Miller cycle in which the piston closes an intake valve before the BDC of the intake stroke so as to allow supply of the fuel gas to the precombustion chamber 4.