| 摘要 |
<p>The invention relates to a dosing system for dosing a reducing agent, in particular an aqueous urea solution, into the exhaust tract of a motor vehicle, comprising a dosing valve (1), a reducing agent storage tank (2) and a delivery module (3) for delivering the reducing agent via a feed line (4) from the storage tank (2) to the dosing valve (1), and also a return line (5) which branches off from the feed line (4) downstream of the delivery module (3) and which is connected to the storage tank (2), wherein the dosing system furthermore has a valve arrangement (6) for realizing a back-suction function. According to the invention, the valve arrangement (6) has a first 2/2 directional valve (7) arranged in the feed line (4) upstream of the delivery module (3) and has a second 2/2 directional valve (9) arranged in a bypass line (8), or is designed as a 3/2 directional valve (10). The invention also relates to a 3/2 directional valve for a dosing system of said type.</p> |
