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AssigneeVolkswagen Aktiengesellschaft
InventorsEkkehard Pott, Eric Bree, Kai Philipp, Michael Zillmer
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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 (Δt) of the injection valve (22) from falling below a preset valve opening time (ΔtK) 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.
Method for controlling fuel metering of a direct-injection internal combustion engine (10) in a multiple injection operating mode, wherein at least two fuel injections into a cylinder (12) occur through an injection valve (22) during an operating cycle of a cylinder (12) of the internal combustion engine (10), characterized in that a pressure (rail pressure, pR), at which the fuel is supplied before the injection valve (22), is preset so that a resulting valve open time (Δt) of the injection valve (22) in at least one injection of an operating cycle does not fall below a predetermined valve open time (ΔtK).
Method for controlling fuel metering of a direct-injection internal combustion engine (10) in a multiple injection operating mode, wherein at least two fuel injections into a cylinder (12) occur through an injection valve (22) during an operating cycle of a cylinder (12) of the internal combustion engine (10), characterized in that injected fuel fractions of the individual injections of an operating cycle and/or a total fuel quantity injected during a multiple injection are varied in such a way that a resulting valve open time (Δt) in at least one injection of an operating cycle does not fall below a preset valve open time (ΔtK).
Method according to one of the preceding claims, characterized in that above the preset valve open time (ΔtK) the injection valve (22) operates with an average variance of a fuel throughput (σKS) of a most ±20%, in particular of a most ±15%, in particular of a most ±10%.
Method according to one of the preceding claims, characterized in that the preset valve open time (ΔtK) is 550 μs, in particular 600 μs, in particular 700 μs.
Method according to one of the preceding claims, characterized in that a fuel quantity to be injected during an operating cycle is regulated based on a deviation of an actual fuel quantity from a nominal fuel quantity and that a fuel quantity to be injected through the at least one additional injection of the operating cycle is pilot-controlled.
Method according to one of the preceding claims, characterized in that all injections of an operating cycle are regulated proportional to their fuel fractions to be injected depending on the difference between the actual fuel quantity and the nominal fuel quantity.
Dependencies are inferred from the claim text.