초록 ▼

Disclosed a common-rail fuel-injection system employing an auxiliary injection such as a pilot injection system, in which when a desired amount of fuel to be injected in the auxiliary injection is less than a set value, the feedback control ceases to keep the combustion against becoming unstable. Wh

Disclosed a common-rail fuel-injection system employing an auxiliary injection such as a pilot injection system, in which when a desired amount of fuel to be injected in the auxiliary injection is less than a set value, the feedback control ceases to keep the combustion against becoming unstable. When a desired amount of fuel to be injected in the auxiliary injection is proved on comparison at step 15 to be less than a minimum amount of fuel injected, which is the lower limit detectable according to both of the common-rail pressure and a pressure drop in the common-rail pressure owing to the fuel injection, the minimum amount of fuel injected serves on step 18 as a corrected, desired amount of fuel to be injected in the auxiliary injection. Thus, the fuel injection is achieved in accordance with the corrected, desired amount of fuel to be injected in the auxiliary injection, thereby keeping the feedback control at the auxiliary injection from becoming unstable. As an alternative, the minimum amount of fuel injected may be replaced with a set value, which is defined on the basis of the minimum amount of fuel injected.

대표청구항 ▼

[What is claimed is:] [1.]wherein the controller divides the fuel injection out of the injectors into a major injection and an auxiliary injection in accordance with the signals issued from the detecting means, the auxiliary injection being carried out at any one timing either before or after the ma

[What is claimed is:] [1.]wherein the controller divides the fuel injection out of the injectors into a major injection and an auxiliary injection in accordance with the signals issued from the detecting means, the auxiliary injection being carried out at any one timing either before or after the major injection, finds the desired amount of fuel to be injected in the auxiliary injection in accordance with the signals issued from the detecting means, and further finds an actual amount of fuel injected really in the auxiliary injection on the basis of a pressure drop of the fuel pressure in the common rail, whereby the actual amount of fuel injected in the auxiliary injection is feedback controlled so as to come into coincidence with the desired amount of fuel to be injected in the auxiliary injection, andwherein the controller compares the desired amount of fuel to be injected in the auxiliary injection with a set value, which is found in accordance with the fuel pressure detected at the pressure sensor, and when the desired amount of fuel to be injected in the auxiliary injection is less than the set value, ceases the feedback control.