Exhaust gas aftertreatment system for diesel engine and method of detecting abnormal injection

Abstract

Disclosed is an exhaust gas aftertreatment system () for a diesel engine, the exhaust gas aftertreatment system comprising: a treatment agent tank () for storing an exhaust gas treatment agent; a metering injection module (), with the injection of the metering injection module () being controlled with a determined duty ratio signal according to a desired injection amount; a supply module () connected between the treatment agent tank () and the metering injection module () for supplying the exhaust gas treatment agent to the metering injection module (); an exhaust gas treatment agent pipe () connected between the metering injection module () and the supply module (); a pressure sensor for measuring the system pressure in the exhaust gas treatment agent pipe (); and a controller (); wherein the controller () is configured to receive a system pressure signal from the pressure sensor during injection of the metering injection module (), and detect an injection abnormality of the metering injection module () based on at least a first amount, which represents an actual injection amount and is determined by the system pressure signal, and a second amount, which represents a theoretical injection amount and is determined by a corresponding duty ratio signal. A corresponding injection abnormality detection method is further disclosed. The injection abnormality detection method is simple and reliable.