AN INJECTION SYSTEM WITH VARIABLE ADJUSTMENT OF THE INJECTION TIMING FOR FUEL IN A DIESEL ENGINE WITH HIGH-PRESSURE INJECTION

摘要

In a diesel engine with high-pressure injection the fuel injection timing is adjustable in order to change the maximum pressure (P'max) in a cylinder during the combustion. The engine has several cylinders, each having at least one fuel injector (13) connected with a fuel pump (1) via a high-pressure conduit (9). At initiation of an injection sequence the high-pressure conduit is pressurized by fuel to a pressure being higher that the opening pressure of the fuel injector. The fuel injection timing can be advanced by increasing the flow area in a restricted flow passage (17) leading fuel into a pressure chamber (19) for closure of a drain valve (20). This is effected by an electrically actuated control valve (18) which at failure in the electric control system is adapted to be in the position without increased flow area.