Patent ID: 7195001

Claim:
An engine system comprising: at least one fuel injector sensor coupled to at least one fuel injector of a first group of cylinders; at least one fuel injector sensor coupled to at least one fuel injector of a second group of cylinders; and a controller configured to operate the engine system in at least a first mode and a second mode, where in the first mode the first and second cylinder groups combust air and injected fuel, where in the second mode at least one of the first and second cylinder groups combusts air and injected fuel and the other one of the first and second cylinder groups pumps air without injecting fuel; where in the first mode the controller sets a degradation condition responsive to detection of inactivity of the at least one fuel injector by the at least one fuel injection sensors; and where in the second mode the controller sets a degradation condition responsive to at least one of detection of fuel injection activity in both the first and second groups of cylinders by the fuel injection sensors, and detection of fuel injection inactivity in both the first and second groups of cylinder by the fuel injection sensors.