Dosing system for introducing e.g. urea water solution into exhaust line of combustion engine of motor car to reduce nitrogen oxide in exhaust gas, has capillary barrier switched-on in line near to metering valve and integrated into valve

摘要

The system has a supply tank (3) interconnected with a metering valve (6) over a line (4) for reducing agent i.e. urea water solution. A supply pump (5) is switched-on in the line. A capillary barrier (9) is switched-on in the line close to the metering valve and integrated into the metering valve. The capillary barrier includes a hydrophilic layer and a hydrophobic layer that is turned to the metering valve and formed by a paint layer. The hydrophilic layer is formed from a metallic material such as close stainless steel wire and metal sheet, that is provided with laser bored holes.