Method for melting and heating liquid reducing agent in selective catalytic reduction-exhaust gas after-treatment system for engine of motor vehicle, involves circulating free-flowing liquid reducing agent into gas after-treatment system

摘要

The method involves supplying a free-flowing liquid reducing agent (4) to a dosing device (5) for guiding the reducing agent into an exhaust gas line (6) of an internal-combustion engine (7) through a pipeline. A return line (9) is connected to an upstream of the dosing device, and a valve (10) is inserted into the return pipe. The free-flowing liquid reducing agent is circulated into a selective catalytic reduction (SCR)-exhaust gas after-treatment system (1) that is connected upstream of the dosing device when the reducing agent is heated with a heating device (2a). An independent claim is also included for a selective catalytic reduction (SCR) exhaust gas after-treatment system.