Patent ID: 10024214

Abstract:
An SCR device for a motor vehicle, comprising a tank for storing reducing liquid, an injection device for injection of the reducing liquid into an exhaust gas system of a motor vehicle, a liquid conduit for delivering reducing liquid from the tank to the injection device, a feed pump for conveying reducing liquid in the conduit, and a valve arrangement in the conduit, the valve arrangement designed to interrupt an injection flow in the conduit when the tank-side pressure is greater, than the injection device-side pressure in the conduit by less than an injection threshold value, and to allow the injection flow to pass when the tank-side pressure is greater by at least the injection threshold, the valve arrangement designed to interrupt a return flow in the conduit from the injection device to the tank when the injection device-side pressure is greater than the tank-side pressure by less than a return threshold value, and to allow the return flow to pass through when the injection device-side pressure is greater than the tank-side pressure in the conduit, by at least the return threshold value, the injection threshold value being greater than the return threshold value.