Patent ID: 7594516

Claim:
An exhaust gas cleaning system, comprising: a metering valve, said metering valve comprising: a magnetic part and a hydraulic part, the magnetic part having an armature biased by a spring and the hydraulic part having an annular space for receiving and conveying a urea-water solution received from a liquid inlet, as well as a tappet facing a valve seat, and the valve seat having a nozzle opening on a side facing away from the tappet, said tappet being connected to said armature, and said metering valve being in fluidic communication with a motor vehicle exhaust gas system, wherein: in a currentless state, the tappet blocks the annular space in the direction of said nozzle opening until a freeze expansion space is created by means of a freezing pressure from solidification of the urea-water solution during freezing, the urea-water solution is introduced into the exhaust gas system without use of compressed air; the metering valve has a diaphragm in its interior; and the diaphragm is provided on a side of the tappet facing away from the valve seat; and said freezing pressure of the urea-water solution deforms the diaphragm, by way of a relieving motion of the solidifying urea-water solution, and the deformed diaphragm acts indirectly on the armature which lifts the tappet from the valve seat.