Onboard diagnosis and compensation for tip wear in fuel injector

A fuel control system comprising:

• a fueling control unit structured to:
• determine a test point on a tip wear-sensitive region of a fuel injector delivery curve of a fuel injector, the tip wear-sensitive region including a ballistic region of the fuel injector delivery curve;
• determine a reference point on a tip wear-insensitive region of the fuel injector delivery curve;
• energize an electrical actuator in the fuel injector to inject a fuel, via opening an outlet check of the fuel injector, at the test point on the tip wear-sensitive region of the fuel injector delivery curve;
• store a measurement of a pressure drop in a pressurized fuel reservoir caused by the injection of fuel;
• and
• produce an injector health signal based on the stored measurement of a pressure drop.

A fuel control system comprising:

• a fueling control unit structured to:
• determine a test point on a tip wear-sensitive region of a fuel injector delivery curve of a fuel injector;
• energize an electrical actuator in the fuel injector to inject a fuel, via opening an outlet check of the fuel injector, at the test point on the tip wear-sensitive region of the fuel injector delivery curve;
• store a measurement of a pressure drop in a pressurized fuel reservoir caused by the injection of fuel;
• produce an injector health signal based on the stored measurement of a pressure drop;
• energize the electrical actuator a plurality of times to perform a plurality of injections of fuel from the fuel injector at the test point sequentially;
• store a plurality of pressure drop measurements stepped down sequentially and each caused by one of the plurality of injections of fuel;
• calculate a pressure drop error based on the stored plurality of pressure drop measurements;
• determine a numerical wear factor for the fuel injector based on the pressure drop error;
• and
• calculate a prognostic injector service life term based on the numerical wear factor.

A fuel system for an internal combustion engine comprising:

• a pressurized fuel reservoir;
• a pressure sensor coupled to the pressurized fuel reservoir;
• a plurality of fuel injectors fluidly connected to the pressurized fuel reservoir and each including a control valve electrical actuator, and an outlet check coupled to the control valve electrical actuator;
• and
• a fueling control unit coupled to the pressure sensor, and in control communication with each control valve electrical actuator, and including an injector wear compensation controller;
• the injector wear compensation controller being structured to:
• energize each control valve electrical actuator to inject a fuel from the respective fuel injector;
• receive pressure measurements from the pressure sensor indicative of a pressure drop in the pressurized fuel reservoir caused by each respective injection of fuel;
• calculate a pressure drop error for each respective fuel injector based on the corresponding pressure measurements;
• electronically trim each respective fuel injector based on the corresponding pressure drop error;
• calculate a numerical wear factor for each fuel injector based on the respective pressure drop error;
• and
• calculate a prognostic injector service life term for each fuel injector based on the respective numerical wear factor.