Method and system for characterizing a port fuel injector
AssigneeFord Global Technologies, LLC
InventorsRoss Dykstra Pursifull, Adithya Pravarun Re Ranga, Gopichandra Surnilla
Life of this patent
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Abstract
Methods and systems are provided for calibrating engine port injectors. After pressurizing a low pressure fuel rail, a lift pump may be disabled and port injector variability may be correlated with a measured fuel rail pressure drop at each port injection event by sweeping injection pressure while maintaining injection voltage, and then sweeping injection voltage while maintaining injection pressure. A port injector variability map learned as a function of injection voltage and injection pressure is then transformed into a map learned as a function of injection current and injection pressure by accounting for injector variability caused due to changes in injector temperature.
Claims20
A method for an engine, comprising:
- port fueling an engine with a fuel rail pressure above a threshold pressure, a lift pump disabled, and while maintaining a base injection pressure and varying injection voltage and maintaining a base injection voltage and varying injection pressure;
- learning variability between port injectors of the engine based on a measured drop in the fuel rail pressure, as a function of each of injection pressure and injection voltage, for each injection event of the port fueling;
- and
- adjusting subsequent port fueling of the engine based on the learning.
A method for an engine, comprising:
- operating a lift pump to raise a port injection fuel rail pressure above a threshold pressure and then disabling the lift pump;
- for a predefined number of subsequent port injection events:
- sequentially operating a plurality of port injectors of the engine while maintaining a base injection pressure and sweeping injection voltage and while maintaining a base injection voltage and sweeping injection pressure;
- correlating a fuel rail pressure drop at each port injection event, as a function of injection pressure and injection voltage, to a parameter indicative of injector variability for a corresponding port injector;
- and
- after the predefined number of subsequent port injection events, adjusting a fuel pulse-width commanded to each port injector based on the parameter indicative of injector variability for the corresponding port injector.
An engine system, comprising:
- an engine including a plurality of cylinders;
- a fuel injection system including a low pressure lift pump, a port injection fuel rail coupled to the lift pump via a fuel line, a plurality of port injectors coupled to the plurality of cylinders, and a pressure relief valve coupled to the fuel line, upstream of the fuel rail;
- a pressure sensor and a temperature sensor coupled to the fuel rail;
- a pedal position sensor for receiving an operator torque demand;
- and
- a controller with computer readable instructions stored on non-transitory memory the controller executing the instructions to:
- operate the lift pump until a fuel rail pressure exceeds a threshold pressure, and then disabling the lift pump;
- sequentially operate each of the plurality of port injectors for a predefined number of injection events;
- the sequential operating including commanding an injector pulse-width based on the operator torque demand, maintaining a base injection pressure and sweeping injection voltage, and maintaining a base injection voltage and sweeping injection pressure;
- for each of the plurality of port injectors, update a map of injected fuel mass relative to injector pulse-width by correlating a fuel rail pressure drop at each of the predefined number of injection events to one or more of a slope and an offset of the map, the fuel rail pressure drop correlated as a function of each of injection voltage and injection pressure;
- and
- after the predefined number of injection events, operate the plurality of port injectors in accordance with the updated map.
Dependencies are inferred from the claim text.