Fuel control system including adaptive injected fuel quantity estimation

A fuel control system for an internal combustion engine, the system comprising:

• a fuel collection unit configured to store pressurized fuel therein;
• a fuel injector configured to inject a quantity of fuel from said fuel collection unit into a combustion cylinder of an internal combustion engine;
• means for determining a first energy level associated with said fuel collection unit prior to injection of said quantity of fuel and a second energy level associated with said fuel collection unit after injection of said quantity of fuel;
• means for determining an injection pressure corresponding to a pressure of said quantity of fuel injected by said fuel injector;
• and
• a control circuit determining a first amount of fuel supplied by said fuel collection unit to said fuel injector as a function of said first and second energy levels, a second amount of fuel corresponding to a portion of said first amount of fuel directed by said fuel injector back to a fuel supply as a function of said injection pressure, and a parasitic fuel leakage value as a function of said first and second energy levels, said control circuit determining an estimate of said quantity of fuel by subtracting said second amount of fuel and said parasitic fuel leakage value from said first amount of fuel.

A fuel control system for an internal combustion engine, the system comprising:

• a fuel collection unit configured to store pressurized fuel therein;
• a fuel injector configured to inject a quantity of fuel from said fuel collection unit into a combustion cylinder of an internal combustion engine;
• a pressure sensor operable to sense pressure of said pressurized fuel within said fuel collection unit and produce a pressure signal corresponding thereto;
• an engine position sensor determining a rotational position of said engine relative to a reference position and producing an engine position signal corresponding thereto;
• and
• a control circuit responsive to said pressure signal and said engine position signal to determine a pressure change value as a difference between said pressure signal for a first engine position range prior to injection of said quantity of fuel and said pressure signal for a second engine position range after injection of said quantity of fuel, and to determine a first slope of said pressure signal within said first engine position range and a second slope of said pressure signal within said second engine position range, said control circuit determining an estimate of said quantity of fuel as a function of said pressure change value, said first slope and said second slope.

A fuel control system for an internal combustion engine, the system comprising:

• a fuel collection unit configured to store pressurized fuel therein;
• a fuel injector configured to inject a quantity of fuel from said fuel collection unit into a combustion cylinder of an internal combustion engine;
• a pressure sensor operable to sense pressure of said pressurized fuel within said fuel collection unit and produce a pressure signal corresponding thereto;
• and
• a control circuit determining a bulk modulus of said pressurized fuel as a function of a rate of change of said pressure signal over a fuel pressure range and determining a pressure change value as a difference between said pressure signal prior to injection of said quantity of fuel and said pressure signal after injection of said quantity of fuel, said control circuit determining an estimate of said quantity of fuel as a function of said pressure change value and said bulk modulus.