Device and method for denoxing exhaust gas from an internal combustion engine
AssigneeSiemens Aktiengesellschaft
InventorRainer Tost
Life of this patent
Estimating the term…
Abstract
A device and a method for deNOxing exhaust gas from an internal combustion engine includes taking into account an amount of gaseous reducing agent (ammonia) that escapes while the internal combustion engine is at a stand-still as a result of temperature influences in a calculation of the amount of reducing-agent solution (urea) that is to be metered when the internal combustion engine is operating. The gaseous reducing agent is passed to the reduction catalytic converter through a pressure-relief line that includes a pressure-control valve, and, in the method, the amount is recorded by a flowmeter.
Claims15
A device for deNOxing exhaust gas from an internal combustion engine having an exhaust pipe conveying exhaust gas in an exhaust direction, comprising:
- a reduction catalytic converter operating under an SCR principle, said converter, disposed in the exhaust pipe;
- a reducing-agent reservoir for holding a reducing agent;
- a metering device for introducing said reducing agent into exhaust gas flowing to said converter;
- a reducing-agent pump for delivering said reducing agent from said reservoir to said metering device;
- said pump fluidically connecting said reservoir to said metering device;
- said metering device fluidically connecting said pump to the exhaust pipe upstream of said converter with respect to the exhaust direction;
- a pressure-relief line for feeding excess reducing agent from said reservoir to said converter;
- said pressure-relief line fluidically connecting said reservoir to said converter;
- and
- a flow-measuring device for recording an amount of excess reducing agent passing through said pressure-relief line, said flow-measuring device disposed in said pressure-relief line.
In an internal combustion engine having an exhaust pipe conveying exhaust gas in an exhaust direction, a device for deNOxing exhaust gas in the exhaust pipe comprising:
- a reduction catalytic converter operating under an SCR principle, said converter, disposed in the exhaust pipe;
- a reducing-agent reservoir for holding a reducing agent;
- a metering device for introducing said reducing agent into the exhaust gas flowing to said converter;
- a reducing-agent pump for delivering said reducing agent from said reservoir to said metering device;
- said pump fluidically connecting said reservoir to said metering device;
- said metering device fluidically connecting said pump to the exhaust pipe upstream of said converter with respect to the exhaust direction;
- a pressure-relief line for feeding excess reducing agent from said reservoir to said converter;
- said pressure-relief line fluidically connecting said reservoir to said converter;
- and
- a flow-measuring device for recording an amount of excess reducing agent passing through said pressure-relief line, said flow-measuring device disposed in said pressure-relief line.
A method for deNOxing exhaust gas from an internal combustion engine, which comprises:
- determining, as a function of operating parameters of at least one of the internal combustion engine and a reduction catalytic converter operating under an SCR principle, an amount of reducing-agent solution to be metered and introducing the amount of the reducing agent into an exhaust pipe upstream of the converter while the internal combustion engine is operating;
- when the internal combustion engine is at a stand-still, feeding gaseous reducing agent formed as a result of temperature effects to the converter;
- and
- recording and taking into account an amount of the gaseous reducing agent during a determination of an amount of reducing-agent solution to be metered during operation of the internal combustion engine.
Dependencies are inferred from the claim text.