Patent ID: 8281766

Claim:
A fuel injection system comprising: two or more intake ports that are communicated with a combustion chamber; two or more intake valves, each of which is placed in an end portion of a corresponding one of the two or more intake ports to open and close a connection between the corresponding intake port and the combustion chamber; two or more fuel injection valves, each of which is placed in a corresponding one of the two or more intake ports to inject fuel into intake air that flows in the corresponding intake port; and an injection quantity control means for controlling an injection quantity of fuel at each of the two or more fuel injection valves, wherein: the total number of the two or more fuel injection valves is the same as the total number of the two or more intake valves; the two or more fuel injection valves have different injection quantities of fuel per unit time, respectively; the injection quantity control means controls injection start timing and injection end timing of each of the two or more fuel injection valves based on an operational state of the internal combustion engine; the injection quantity control means executes injection of fuel from one of the two or more fuel injection valves, which has a small injection quantity of fuel per unit time, while stopping injection of fuel from another one of the two or more fuel injection valves, which has a large injection quantity of fuel per unit time that is larger than the small injection quantity of fuel per unit time, until opening of the two or more intake ports by the two or more intake valves when the following two conditions are satisfied: time elapsed since starting of the internal combustion engine is still within a predetermined time period; and a temperature of the internal combustion engine is equal to or less than a predetermined value; and the injection quantity control means executes injection of fuel from the another one of the two or more fuel injection valves, which has the large injection quantity of fuel per unit time, during opening of the two or more intake ports by the two or more intake valves when a load of the internal combustion engine is equal to or larger than a predetermined value in a state where the two conditions are not satisfied, such that the time elapsed since the starting of the internal combustion engine is longer than the predetermined time period, and the temperature of the internal combustion engine is greater than the predetermined value.