After-treatment system for after-treatment of exhaust gas in diesel engine vehicle, has selective catalytic reduction catalyzer arranged upstream of exhaust pipe, and injection device injecting reducing agent through piezo-medium pump

摘要

The system has a selective catalytic reduction (SCR) catalyzer arranged upstream of an exhaust pipe, and an injection device injecting a reducing agent from a reducing agent tank through a pump, where the pump is a piezo-medium pump including two piezo-elements (1a, 1b). The pump includes pistons (4a, 4b) guided within a cylinder, where a working space (5) is defined between the pistons.