Device for exhaust-gas purification, and an operating and monitoring for said device
First Claim
1. A device for exhaust-gas purification involving reduction of nitrogen oxides, which are present in the exhaust gas from internal combustion engines, comprising an SCR catalytic converter using ammonia, at least one pressure vessel having a filling which releases gaseous ammonia when heat is supplied, and a metering unit downstream of the pressure vessel in a transition to the SCR catalytic converter, which metering unit is an ammonia source, wherein the pressure vessel filling is liquid ammonia, and at least the metering unit is arranged in a gastight, pressure-monitored housing.
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Accused Products
Abstract
A device for exhaust-gas purification utilizes reduction of nitrogen oxides which are present in the exhaust gas from internal combustion engines by way of gaseous ammonia with an SCR catalytic converter. The functions of the device are monitored with regard to their line paths with connections, valves and sensors by referring to these elements themselves using suitable control circuitry via the evaluation and control unit.
53 Citations
43 Claims
- 1. A device for exhaust-gas purification involving reduction of nitrogen oxides, which are present in the exhaust gas from internal combustion engines, comprising an SCR catalytic converter using ammonia, at least one pressure vessel having a filling which releases gaseous ammonia when heat is supplied, and a metering unit downstream of the pressure vessel in a transition to the SCR catalytic converter, which metering unit is an ammonia source, wherein the pressure vessel filling is liquid ammonia, and at least the metering unit is arranged in a gastight, pressure-monitored housing.
- 34. A method for operating a device for exhaust-gas purification involving reduction of nitrogen oxides which are present in the exhaust gas from a motor vehicle internal combustion engine, having an SOR catalytic converter using ammonia, at least one pressure vessel having a filling which releases gaseous ammonia when heat is supplied, a metering unit located downstream of a the pressure in a transition to the SCR catalytic converter and a temporary store (18) located between a shut-off valve and a metering valve, comprising alternatively filling the temporary store in a pressure-limited manner, from the pressure vessel when the metering valve is closed and then emptying the temporary store via the metering valve down to a minimum pressure when the shut-off valve is closed, wherein when the internal combustion engine is being switched off, the temporary store is emptied to a exhaust section of the internal combustion engine.
- 36. A method for monitoring a device for exhaust-gas purification involving reduction of nitrogen oxides which are present in exhaust gas from a motor vehicle internal combustion engine, wherein the device has an SCR catalytic converter using ammonia, at least one pressure vessel having a filling which releases gaseous ammonia when heat is supplied, and a metering unit downstream of the pressure vessel in a transition to the SCR catalytic converter, which metering unit is an ammonia source, wherein the pressure vessel filling is liquid ammonia, and at least the metering unit is arranged in a gastight, pressure-monitored housing, comprising processing pressure values obtained from a pressure recording in the metering unit, and a housing which surrounds the metering unit in an evaluation and control unit and converting the processed pressure values into control signals for at least one of valves, heater and warning signals.
Specification