Abstract: A fuel system has a fuel rail containing pressured fuel coupled to a plurality of fuel injectors. The system is operable in one embodiment to adjust fuel injector on-times by selecting one of the fuel injectors, determining a critical on-time for the selected injector corresponding to a minimum on-time duration to which the selected fuel injector is responsive to inject a discernable amount of fuel, generating an on-time for the selected fuel injector, determining an adjusted on-time for the selected fuel injector based on the generated on-time for the selected fuel injector, the critical on-time for the selected fuel injector and a reference critical on-time, and activating the selected fuel injector for the adjusted on-time to inject fuel into the engine. Alternatively or additionally, the adjusted on-time may be based on one or more estimated fuel injection quantities injected by the selected fuel injector.

Abstract: A fuel system has a source of fuel coupled to a plurality of fuel injectors via a fuel rail. The system is operable to estimate a quantity of fuel injected into an internal combustion engine by disabling fuel flow from the source of fuel to the fuel rail, and monitoring a fuel request corresponding to a request for delivery of fuel by the fuel system to the engine produced by the engine. If the fuel request is below a threshold fueling level a selected fuel injector is controlled to inject a selected quantity of fuel from the fuel rail into the engine while inhibiting fuel injection the remaining fuel injectors, fuel rail pressure is sampled, a drop in the fuel rail pressure, resulting from injection of the selected quantity of fuel, is determined from the fuel rail pressure samples, and the quantity of fuel injected by the selected injector is determined as a function of the drop in fuel rail pressure.

Abstract: A fuel system has a source of fuel coupled to a plurality of fuel injectors via a fuel rail. The system is operable to determining a critical on-time for a selected one of the injectors by disabling fuel flow from the source of fuel to the fuel rail, periodically sampling fuel rail pressure, activating the selected injector for an on-time duration while inhibiting injection by remaining ones of the injectors, determining from the fuel rail pressure samples a pressure drop resulting from activation of the selected injector for the on-time duration, processing the pressure drop to determine whether or not the selected injector injected fuel, and repeatedly modifying the on-time duration followed by executing the sampling, activating, determining and processing steps until a critical on-time is determined that corresponds to a minimum on-time duration to which the selected fuel injector is responsive to inject a discernable amount of fuel.

Abstract: A fuel system has a source of fuel coupled to a plurality of fuel injectors via a fuel rail. The system is operable to determining a critical on-time for a selected one of the injectors by disabling fuel flow from the source of fuel to the fuel rail, periodically sampling fuel rail pressure, activating the selected injector for an on-time duration while inhibiting injection by remaining ones of the injectors, determining from the fuel rail pressure samples a pressure drop resulting from activation of the selected injector for the on-time duration, processing the pressure drop to determine whether or not the selected injector injected fuel, and repeatedly modifying the on-time duration followed by executing the sampling, activating, determining and processing steps until a critical on-time is determined that corresponds to a minimum on-time duration to which the selected fuel injector is responsive to inject a discernable amount of fuel.

Abstract: A fuel system has a source of fuel coupled to a plurality of fuel injectors via a fuel rail. The system is operable to estimate a quantity of fuel injected into an internal combustion engine by disabling fuel flow from the source of fuel to the fuel rail, and monitoring a fuel request corresponding to a request for delivery of fuel by the fuel system to the engine produced by the engine. If the fuel request is below a threshold fueling level a selected fuel injector is controlled to inject a selected quantity of fuel from the fuel rail into the engine while inhibiting fuel injection the remaining fuel injectors, fuel rail pressure is sampled, a drop in the fuel rail pressure, resulting from injection of the selected quantity of fuel, is determined from the fuel rail pressure samples, and the quantity of fuel injected by the selected injector is determined as a function of the drop in fuel rail pressure.

Abstract: A fuel system has a fuel rail containing pressured fuel coupled to a plurality of fuel injectors. The system is operable in one embodiment to adjust fuel injector on-times by selecting one of the fuel injectors, determining a critical on-time for the selected injector corresponding to a minimum on-time duration to which the selected fuel injector is responsive to inject a discernable amount of fuel, generating an on-time for the selected fuel injector, determining an adjusted on-time for the selected fuel injector based on the generated on-time for the selected fuel injector, the critical on-time for the selected fuel injector and a reference critical on-time, and activating the selected fuel injector for the adjusted on-time to inject fuel into the engine. Alternatively or additionally, the adjusted on-time may be based on one or more estimated fuel injection quantities injected by the selected fuel injector.