Arrangement for an after treatment of exhaust gases from an internal combustion engine
AssigneeRobert Bosch GmbH
InventorsErnst Linder, Hubert Dettling
Life of this patent
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Abstract
To reduce NO.sub.x components in the exhaust gas from a compression-ignition internal combustion engine with the aid of a reducing catalytic converter, a metering device for the supply of reducing agent to be additionally introduced into the exhaust gas, in the form of fuel, is provided to improve the performance of the catalytic converter. For this purpose, use is made of a positive displacement pump designed to meter very small quantities with a helix in the form of a helical groove arranged on a cylindrical body of revolution, the delivery rate being varied by driving the body of revolution at a variable rotational speed.
Claims23
An arrangement for an after-treatment of exhaust gases from a compression-ignition internal combustion engine, in an exhaust-gas collecting system (3) of which a reducing catalytic converter (5) for reducing NO.sub.x components of the exhaust gas from the internal combustion engine is arranged, a metering device (12) controlled by a control device (9) and serving for the metered introduction of a reducing agent into the stream of exhaust gas fed to the catalytic converter as a function of values, stored in a characteristic map, for the NO.sub.x content of the exhaust gas given various operating parameters of the internal combustion engine and of the catalytic converter, and with an air feed pump arranged upstream of the metering device and serving for the finely dispersed preparation of the reducing agent to be introduced, the metering device (12) comprises a continuous-delivery positive displacement pump (14) driven at a variable rotational speeds controlled by the control device (9).
Dependencies are inferred from the claim text.