Patent ID: 8209108

Claim:
A control method for a fuel injection device which is applied to an internal combustion engine having a fuel injection valve that injects fuel directly into a combustion chamber, a supercharger that forces air into the combustion chamber, and an exhaust purification device provided on an exhaust passageway, and which executes, as a fuel injection from the fuel injection valve, a post-injection that is a fuel injection during an expansion stroke or an exhaust stroke, separately from the fuel injection for torque generation, the control method comprising: detecting a rotation speed of an engine output shaft; detecting an air amount that flows in the intake passageway upstream of the supercharger in an air flow direction; detecting an air pressure inside the intake passageway downstream of the supercharger in the air flow direction; calculating a correction term based on a rate of change of the air pressure detected; setting an upper-limit injection amount based on the rotation speed of the engine output shaft, the air amount, the correction term, and a fuel injection amount in the fuel injection for torque generation; and restricting the fuel injection amount in the post-injection with the upper-limit injection amount.