Pilot injection controller in fuel injection system and method of controlling pilot injection quantity

摘要

A pilot injection controller and a method of controlling pilot injection quantity enable the quantity of fuel pilot-injected fuel by an internal combustion engine fuel injection system of the type in which the fuel delivery stroke for pilot injection is fixed to be maintained substantially constant irrespective of engine speed by controlling prestroke such that the utilized portion of a cam is shifted to a lower delivery velocity region thereof with increasing engine speed, the principle involved being that the quantity of fuel pilot-injected by a fuel injection system is proportional to the actual plunger delivery velocity and the fact that since the actual delivery velocity is proportional to the product of the cam velocity constant and the cam rotational speed the actual delivery velocity can be maintained substantially constant by increasing the cam velocity constant in the low speed region and decreasing the cam velocity constant in the high speed region.