Method and apparatus for metering a reducing agent for removing nitrogen oxides from exhaust gases
AssigneeRobert Bosch GmbH
InventorsSven Huber, Hanspeter Mayer, Gerhard Mueller, Michael Offenhuber
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Abstract
A method and an apparatus for metering a reducing agent in which the reducing agent is delivered, via a line and a final control element that regulates the metering, in particular a metering valve, to a catalytic converter assembly for removing nitrogen oxides from the exhaust gases, in particular of a Diesel engine; a pressure drop in the line dictated especially by gas inclusions is detected, and the line is ventilated via the final control element.
Claims13
A method for metering a reducing agent in which the reducing agent is delivered via a line (12) and a metering valve (7) that regulates the metering to a catalytic converter assembly (30) for removing nitrogen oxides from the exhaust gases from an internal combustion engine, the method including detecting a pressure drop produced in the line (12) and ventilating the line (12) by opening the metering valve (7), wherein the metering valve (7) is opened for ventilating the line (12) as a function of the magnitude of the pressure drop in the line.
An apparatus for metering a urea or urea-water solution reducing agent into an exhaust gas stream, the apparatus comprising means (2, 3, 4) for delivering reducing agent to a catalytic converter assembly (30) for removing nitrogen oxides from the exhaust gases from an internal combustion engine, the means being connected via a line (12) to a metering valve (7) that regulates the metering, a measuring element (50) for measuring the pressure in the line (12), or for measuring a measurement variable correlating with the pressure, and a control means (40) for ventilating the line (12) by opening the metering valve (7), if a pressure drop in the line (12) is detected by the measuring element (50), wherein the control means (40) include a memory for storing a performance graph, so that the metering valve (7) can be opened for ventilation as a function of the magnitude of the pressure drop in the line.
Dependencies are inferred from the claim text.