METHODS FOR CONTROLLING A FUEL METERING IN THE MULTIPLE INJECTION OPERATING MODE

摘要

The invention relates to two methods for controlling a fuel metering of a direct-injection internal combustion engine (10) in a multiple injection operating mode according to which at least two fuel injections into a cylinder (12) are carried out during a compression cycle of the cylinder (12) of the internal combustion engine (10) by means of at least one injection valve (22). The invention provides that a pressure (rail pressure, pR), under which the fuel is stored in front of the injection valve (22), is preset in such a manner and/or injected fuel portions of the individual injections of a combustion cycle and/or a total fuel quantity, which is injected during a multiple injection, are varied in such a manner as to prevent a forthcoming valve opening time ( DELTA t) of the injection valve (22) from falling below a preset valve opening time ( DELTA tK) during at least one injection of a combustion cycle. The inventive measures ensure, with simple means, a precise fuel metering in the multiple injection operating mode and thus enable an application of the multiple injection operating mode over wide operating ranges, particularly also in the low load operating mode and idle operating mode.