Abstract: A system and method of operating an internal combustion engine (ICE) having a plurality of cylinders. The system includes port and direct fuel injectors configured to inject fuel to each cylinder and an engine control module (ECM) in communication with the port fuel and direct fuel injectors,. The ECM is configured to selectively deactivate and activate each cylinder of the plurality cylinders by either halting or initiating fuel injection into the cylinders and selectively transition fuel injection modes. The ECM is further configured to inject make-up direct injection of fuel into selected cylinders, based in part, on whether the cylinder transitioned from a direct injection (DI) mode into a port fuel injection (PFI) mode, from the DI mode to a port direct injection (PDI) mode, or from a PDI to a PFI mode, whether the cylinder received an actual PFI injection, and other engine variables.

Abstract: A method for controlling a plurality of fuel injectors for a vehicle may include determining a total fuel mass for a combustion stage in a cylinder. The method further may include determining a first injection mass for a first fuel injector and a second injection mass for a second fuel injector. A sum of the first injection mass and the second injection mass is equal to the total fuel mass. The first fuel injector and the second fuel injector are configured to provide fuel to the cylinder. A first minimum mass per pulse of the first fuel injector is greater than a second minimum mass per pulse of the second fuel injector. The method further may include controlling the first fuel injector and the second fuel injector based at least in part on the first injection mass and the second injection mass.

Abstract: Ignition modules for directly applying spark plug drive signals to spark plug pairs disposed in engine cylinders are diagnosed by issuing drive signals to the ignition modules and then monitoring the corresponding engine cylinders for misfire condition patterns. Consistent misfire activity in each cylinder controlled by an individual ignition module is interpreted as a fault condition in the ignition module or in its peripheral circuitry, facilitating fault condition identification and treatment.