FUEL INJECTION DEVICE FOR INTERNAL COMBUSTION ENGINES, AND FUEL INJECTION METHOD FOR INTERNAL COMBUSTION ENGINES

摘要

The purpose of the present invention is to prevent the decrease in fuel injection pressure and the deterioration in combustion performance to thereby prevent the deterioration in performance of an internal combustion engine and also prevent the increase in smoke dust or black smoke even when only a fuel oil is injected into a cylinder liner. Provided is a fuel injection device (1) for internal combustion engines, which has at least two fuel injection valves (10) per one cylinder, wherein each of the fuel injection valves (10) comprises a valve opening pressure control unit (30) for controlling the valve opening pressure of a needle valve (15). The fuel injection device (1) is so adapted that a fuel oil and an inert substance are injected through all of the fuel injection valves (10) when the fuel oil and the inert substance are to be injected into a cylinder liner, and that the valve opening pressure control unit (30) is operated so that the needle valve (15) of at least one fuel injection valve (10) among the at least two fuel injection valves (10) can be compressed by a force having a pressure equal to or higher than the valve opening pressure of the needle valve (15) to thereby block the fuel injection through the fuel injection valve (10) when only the fuel oil is to be injected into the cylinder liner.