Catalyst diagnostics process for testing conversion capacity of IC engine exhaust gas catalyst

摘要

The IC engine exhaust gas catalyst diagnostics process, using signals from an exhaust gas probe downstream of the catalyst, involves simulating combustion cutout in the engine and evaluating the probe reaction. Preferred Features: One or more cutouts are simulated by switch-off of fuel supply to one or more of the engine cylinders. The simulation is only carried out on occurrence of certain conditions, including a defined catalyst operating state in which the probe signals a rich mixture composition. Several cutouts may be simulated such that the air quantity pumped into the exhaust gas provides an oxygen quantity corresponding to the oxygen storage capacity of the catalyst, marking the boundary between good and poor catalysts, a fault signal being emitted and/or stored when the probe signal departs from a predetermined bandwidth. An Independent claim is also included for catalyst diagnostics equipment comprising a system for evaluating the probe response to the above process and optionally for emitting and/or storing a fault signal.