Method for detecting the minimum opening time of a reducing agent feed device in an exhaust gas aftertreatment system comprising an SCR catalyst

A control device for controlling an exhaust gas aftertreatment system, wherein the control device is comprises computer logic stored in non-transitory computer-readable media and executable by a processor to:

• determine a minimum opening time of the reducing agent feed device during operation by a process including:
• select an opening time of the reducing agent feed device,
• operate the reducing agent feed device according to the opening time,
• determine whether a reducing agent-sensitive sensor in the exhaust gas aftertreatment system detects a presence of the reducing agent as a result of the reducing agent feed device being operated according to the opening time,
• in response to the reducing agent-sensitive sensor not detecting the presence of the reducing agent, automatically incrementally increase the opening time of the reducing agent feed device by a predetermined incremental time period, and
• repeat the operating, determining, and incrementing steps until the reducing agent-sensitive sensor detects the presence of the reducing agent, such that the incrementally increased opening time at which the reducing agent-sensitive sensor detects the presence of the reducing agent is determined as the minimum opening time of the reducing agent feed device,
• wherein nitrogen oxide emission is suspended during the determination of the minimum opening time of the reducing agent feed device.