System and method for monitoring an exhaust gas purification system

A method for monitoring an exhaust gas purification system that is functionally connected to a ship's engine and that includes a scrubber for purifying exhaust gas of the ship's engine by using washing water and a device for treating the water that is conducted through the scrubber, the method comprising:

• acquiring an emission signal is acquired by means of an emission sensor, wherein the emission signal indicates emissions of the ship's engine on the exiting from the exhaust gas purification system,
• acquiring measurement signals that are each related to the exhaust gas purification system are acquired by a plurality of further sensors,
• wherein the plurality of further sensors comprise a sensor that indicates the condition of the water after the treatment and before the return to the sea or body of water, and sensors that are installed at or in components of a ship and that define the exhaust gas quantity being received from the exhaust gas purification system,
• determining a process state of the exhaust gas purification system based on the measurement signals of the plurality of further sensors,
• assessing the emission signal and the process state with respect to an anomaly in each case,
• determining and outputting a compliant emission state that indicates a correct functionality of the exhaust gas purification system when no anomaly of the emission signal is present and when an anomaly of the emission signal is present while at the same time no anomaly of the process state is determined or the anomaly of the emission signal satisfies an exception condition, and
• calculating a substitute signal for the emission signal based on the measurement signals of the plurality of further sensors when an anomaly of the emission signal is present and no anomaly of the process state is present, and
• outputting a specific error message when an anomaly of the process state is present and when the anomaly of the emission signal does not satisfy the exception condition.

A system for monitoring an exhaust gas purification system that is functionally connected to a ship's engine and that includes a scrubber for purifying exhaust gas of the ship's engine by using washing water and a device for treating the water that is conducted through the scrubber, wherein the system comprises:

• an emission sensor that acquires an emission signal that indicates emissions of the ship's engine exiting from the exhaust gas purification system,
• a plurality of further sensors that output respective measurement signals related to the exhaust gas purification system, wherein the plurality of further sensors comprise a sensor that indicates the condition of the water after the treatment and before the return to the sea or body of water, and sensors that are installed at or in components of a ship and that define the exhaust gas quantity being received from the exhaust gas purification system, and
• an electronic processing unit that is configured:
• to determine a process state of the exhaust gas purification system based on the measurement signals of the plurality of further sensors,
• to assess the emission signal and the process state with respect to an anomaly in each case,
• to determine and to output a compliant emission state, which indicates a correct functionality of the exhaust gas purification system, when no anomaly of the emission signal is present and when an anomaly of the emission signal is present while at the same time no anomaly of the process state is present or the anomaly of the emission signal satisfies an exception condition,
• wherein the electronic processing unit determines a number of valid process parameters that can be determined based on the measurement signals of the plurality of further sensors and only assesses the process state with respect to an anomaly when the number of valid process parameters is greater than a predetermined value, and otherwise outputs a specific error message.