Robert Boschgmbh

Jens Reinhold

Marc Chaineux

Stephan Pohl

A method for operating an electromagnetically actuated metering valve, which is loaded with a pulse-width modulated metering signal, which stipulates the dosage of a reagent or a precursor of the reagent introduced into the exhaust gas region of an internal combustion engine and an apparatus for implementing the method are proposed. A clock signal is provided, whose cycle duration is smaller than the cycle duration of the pulse-width modulated metering signal. The cycle duration of the pulse-width modulated metering signal is set as a function of a metering request signal to multiples of the cycle durations of the clock signal. The procedural approach according to the invention allows for a rapid adaptation of the dosage to the metering demands.

Method for operating a metering valve and apparatus for implementing the method

The present invention relates to a method for operating an electromagnetically controllable metering valve, which is disposed in an exhaust gas system of an internal combustion engine. For a metering of reducing agent in the exhaust gas system, the metering valve is actuated by a control and/or regulating device via an electromechanical drive unit with a first current profile, which includes a holding current phase having a first holding current level when said metering valve is open. Said metering valve and the drive unit are part of a metering module. When the internal combustion engine is switched off, said metering valve is actuated via said drive unit with a second current profile, which has a second holding current level that is increased with respect to the first holding current level. An independent claim relates to a control device set up to carry out the method.

Method for heating a metering valve in an SCR system for the exhaust gas aftertreatment of an internal combustion engine

Procedure for operating an electromagnetically operated metering valve, which is impinged with a metering signal, which determines the metering of a reagent or a precursor of a reagent that has to be injected into the exhaust gas area of a combustion engine, is thereby characterized, in that the reagent pressure is detected at an opened metering valve in a default cycle, which indicates the reagent flow and in that the reagent flow is added over the opening time of the valve for determining the actual metering amount.

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Backnang, Germany

Jens Reinhold