Method and device for fuel injection for engines

A fuel injection device for engines comprising:

• a common rail to store fuel delivered by a fuel pump;
• injectors formed with injection holes through which to inject the fuel supplied from the common rail into combustion chambers;
• an operation state detection means to detect an operating condition of the engine;
• a pressure sensor to detect a pressure of the common rail;
• and
• a controller to determine a basic fuel injection amount and a target pressure of the common rail based on the engine operating condition detected by the operation state detection means and to control the fuel pump to match the common rail pressure detected by the pressure sensor with the common rail target pressure;
• wherein the controller sets a first fuel injection amount as an amount that stabilizes the engine revolution speed when the engine is running with no load, and
• wherein when a pressure condition is met in which the common rail pressure is higher than the common rail target pressure is higher than the common rail target pressure by more than a predetermined value, and also an injection amount is smaller than the second fuel injection amount which is smaller than the first fuel injection amount, the controller sets the amount of fuel to be injected from the injectors to the second fuel injection amount.