Abstract: An objective of the present invention is to provide a fuel injection pump wherewith, in addition to main injection, pre-injection is made possible in the vicinity of top dead center in the exhaust stroke, and wherewith, by regulating the pre-stroke, defined as the stroke from bottom dead center of a plunger 2 to the commencement of fuel line pressurization, it is possible to freely control both the pre-injection volume and the pre-injection timing relative to the main injection. Attention having been given to the combining of a pre-stroke varying mechanism together with a two-stage injection mechanism, the present invention is a fuel injection pump that is made so that a pre-stroke is regulated by changing the relative positions, in the axial direction, of a plunger 2 that sends fuel under pressure and a control sleeve 3 that fits around the outside of the plunger 2 so as to slide freely thereon.

Abstract: 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.

Abstract: A pilot injection control system for an internal combustion engine comprises a plurality of fuel injection nozzles, the valve-opening pressure of one of which (the reference nozzle) is set slightly higher than that of the other nozzles, means for detecting the pilot injection of the reference nozzle, and means for feedback controlling the pilot injection quantity of the reference nozzle based on the detected pilot injection. The system is able to effectively control the pilot injection of all nozzles by actually controlling the pilot injection of only one nozzle and can therefore be implemented at low cost.