| 摘要 |
<p>The invention relates to a metering system for injecting a urea solution into the exhaust gas flow (9) of an internal combustion engine for selective catalytic reduction, and method for controlling the injecting of a urea solution by means of compressed air, wherein the metering system can be connected to a urea solution tank (1), wherefrom urea solution can be removed, and wherein the metering system can be connected to a compressed air supply (6), wherein the metering system comprises at least one nozzle (5) through which the urea solution can be injected into the exhaust gas flow (9) by means of compressed air, wherein the metering system comprises an air valve (7) by means of which the pressure and/or the quantity of air and/or the valve opening times of the compressed air supply (6) can be regulated, and a sensor for measuring the pressure and/or the quantity of air is disposed in the compressed air supply (6) between the air valve (7) and the nozzle (5), so that the quantity of compressed air fed in for atomizing the urea solution is controlled and lowered to the minimum air quantity required at a given moment, depending on the operating parameters of exhaust gas temperature and exhaust gas mass flow.</p> |
