Patent ID: 7870845

Claim:
A fuel injection control device for controlling an operation of an injector such that fuel to be injected into a combustion chamber per combustion cycle is divided and injected at least through a first injection and a second injection that is performed after the first injection and that injects a larger quantity of the fuel than the first injection, the fuel injection control device comprising: an acquiring means for acquiring a sensing value of cylinder pressure in the combustion chamber sensed with a cylinder pressure sensor; and a first combustion state estimating means for estimating an actual combustion state of the fuel injected by the first injection based upon a second combustion timing cylinder pressure sensing value attributable to combustion of the fuel injected by the second injection out of the cylinder pressure sensing values; wherein the first combustion state estimating means calculates a heat release rate attributable to the combustion of the fuel injected by the second injection based upon the second combustion timing cylinder pressure sensing value and estimates the combustion state based upon the heat release rate; and the first combustion state estimating means estimates the combustion state based upon a time required for the heat release rate to change by a predetermined amount.