Volkswagen Ag

Eric Bree

Ekkehard Pott

Kai Philipp

Michael Zillmer

The invention is directed to a method for controlling the temperature of at least one catalyst arranged in an exhaust gas cleaning system () of a lean-runnable multi-cylinder engine (), wherein energy is introduced into the exhaust gas cleaning system () by a lambda split, and to a corresponding multicylinder engine (). It is provided that the introduction of energy is limited depending on at least one of the parameters catalyst temperature, exhaust gas temperature and exhaust gas mass flow rate, and/or at least one of the parameters change of the catalyst temperature, change of the exhaust gas temperature and change of the exhaust gas mass flow rate, or at least one of the parameters rate of change of the catalyst temperature, rate of change of the exhaust gas temperature and rate of change of the exhaust gas mass flow rate.

Method for controlling the temperature of a catalyst and multicylinder engine comprising a lambda splitting exhaust gas cleaning system

The invention relates to a method for at least temporarily increasing an exhaust gas temperature of a spark-ignition, direction injection internal combustion engine () involving at least one measure, which is executed by the engine, whereby this at least one measure consists of a spark retarding and of a multiple injection (ME). During the multiple injection (ME), at least two fuel injections into the cylinder () are carried out within an induction cycle and compression cycle of a cylinder () of the internal combustion engine (), and the latest of these injections ensues during a compression cycle of the cylinder (). The invention also relates to the utilization of the method. According to the invention, a control end of an injection angle (&#x3b1;) of the latest injection is at least temporarily set to between 80 and 10&#xb0; before an upper ignition dead center (ZOT) when operating with multiple injection and/or an ignition angle (&#x3b1;) is at least temporarily set to between 10 and 45&#xb0; after the upper ignition dead center (ZOT) also when operating with multiple injection. A combination of both measures enables a dramatic acceleration of the warming up of a catalytic converter () that is connected downstream from the internal combustion engine ().

Method for increasing an exhaust gas temperature of a spark-ignition, direct injection internal combustion engine

The invention relates to two methods for controlling a fuel metering of a direct-injection internal combustion engine () in a multiple injection operating mode according to which at least two fuel injections into a cylinder () are carried out during a compression cycle of the cylinder () of the internal combustion engine () by means of at least one injection valve (). The invention provides that a pressure (rail pressure, P), under which the fuel is stored in front of the injection valve (), is present 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 (&#x394;t) of the injection valve () from falling below a preset valve opening time (&#x394;t) 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.

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Wolfsburg, Germany

Eric Bree