To provide a fuel injection device capable of reducing emission quantity of PM in exhaust gas in the whole operation range from light load to heavy load by enabling to raise fuel injection pressure in light load operation range to appropriate injection pressure while maintaining fuel injection pressure at a time of rated load of an engine at an appropriate injection pressure, and a method for operating an internal combustion engine provided with the fuel injection device.
The fuel injection device for the internal combustion engine is constructed to pressurize and send high pressure fuel pressurized by a fuel pump to a fuel injection valve of each cylinder via two fuel control valves. Open and close timing, and valve open quantities of the two fuel control valves are controlled to keep high pressure injection mode in which injection pressure at fixed load is rated injection pressure at rated load or injection pressure close to rated injection pressure as long as the fixed load which does not reach the rated load of the engine. One of the two fuel control valves are opened to a fuel return passage to inhibit rise of injection pressure to the rated injection pressure or higher when load is the fixed load or higher.
KATO YASUO
OGAWA HISAO
Hiroshi Matsumoto
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