Patent ID: 9494069
Filing Date: 2016-11-15
CPC Classification: F01N,Y02T,Y10T

Claim Text:
1. A device for metering a liquid reducing agent into an exhaust system for reducing nitrogen oxides in an exhaust gas, comprising: at least one working tank for keeping a working quantity of the liquid reducing agent on hand; at least one metering module embodied as an injection valve; at least one supply line; at least one feed pump disposed in the supply line, which feed pump feeds the liquid reducing agent from the working tank to the metering module; at least one storage tank for keeping a storage quantity of the liquid reducing agent on hand, the storage tank communicating with the working tank via at least one storage line, wherein at least one storage pump is disposed in the storage line, which storage pump transfers liquid reducing agent from the storage tank to the working tank by pumping the liquid reducing agent through the storage line, and wherein the storage line forms a separate hydraulic path, which does not communicate with the supply line, and at least one reversing valve received in the supply line which at least partially reverses a flow direction through the supply line, wherein the reversing valve is embodied as a 4/2-way valve, with a first inlet of the 4/2-way valve being connected to the working tank, a second inlet of the 4/2-way valve being connected to the metering module, and a third and fourth inlet of the 4/2-way valve each being connected to two different ends of the feed pump.