System, apparatus including on-board diagnostics, and methods for improving operating efficiency and durability of compression ignition engines

A system for use with a compression ignition engine to control for variations in the engine's fuel injection timing resulting from variability in the compressibility and lubricity of fuels used to power the engine, the system comprising:

• a fuel injection controller to control the release of fuel from a fuel supply line in response to a command signal;
• a fuel injector positioned to receive the released fuel and inject the fuel into at least one combustion cylinder of the engine when actuated;
• a fuel injection sensor positioned to sense when the fuel injector is actuated and to generate a sensed signal responsive to the sensed open position;
• an engine controller in communication with the fuel injection controller and the fuel injection sensor, the engine controller including:
• an actual fuel pulse determiner responsive to the sensed signal to determine an actual fuel pulse, Ai, defined as the duration of the time interval that the fuel injector is actuated, the time interval at least partially determined by the compressibility and lubricity of fuel supplied through the fuel supply line,
• a fuel pulse comparator responsive to the actual fuel pulse determiner to compare the actual fuel pulse to a preselected desired fuel pulse, Di, the desired fuel pulse being defined as a desired duration for the fuel injector to be in an open position,
• a fuel pulse compensator responsive to the fuel pulse comparator to compute a fuel pulse compensation factor, k, the compensation factor being defined by the difference obtained by subtracting the actual fuel pulse from the desired fuel pulse, Di−Ai, and
• a command signaler responsive to the fuel pulse compensator and being in communication with the fuel injection controller to generate the command signal based on the desired fuel pulse and compensation factor such that the command signal signals the injection controller to controllably release fuel for a pulse of duration Ci+1=Di+k, so that subsequent actual fuel pulses more closely correspond to the desired fuel pulse.

An apparatus to control for variations in a compression ignition engine's fuel injection timing resulting from variability in the compressibility and lubricity of fuels used to power the engine, the apparatus comprising:

• a fuel injection sensor positioned to sense when a fuel injector is actuated to inject fuel into a combustion chamber of the engine and to generate a sensed fuel injection signal in response thereto;
• an actual fuel pulse determiner responsive to the sensed fuel injection signal to determine an actual fuel pulse, Ai, defined as the duration of the time interval that the fuel injector is actuated to inject fuel into the combustion chamber, the time interval at least partially determined by the compressibility and lubricity of the fuel injected;
• a fuel pulse comparator responsive to the actual fuel pulse determiner to compare the actual fuel pulse to a preselected desired fuel pulse, Di, the desired fuel pulse being defined as a desired duration for the fuel injector to be actuated to inject fuel into the combustion chamber;
• a fuel pulse compensator responsive to the fuel pulse comparator to compute a fuel pulse compensation factor, k, the compensation factor being defined by the difference obtained by subtracting the actual fuel pulse from the desired fuel pulse, Di−Ai, and
• a command signaler responsive to the fuel pulse compensator and being in communication with a fuel injection controller positioned to control fuel injection by the fuel injector in response to a command signal, the command signal being generated by the command signaler based on the desired fuel pulse and compensation factor such that the command signal signals the injection controller to controllably release fuel for a pulse of duration Ci+1=Di+k, so that subsequent actual fuel pulses more closely correspond to the desired fuel pulse.

An apparatus to control for variations in fuel injection timing in a compression ignition engine resulting from variability in the compressibility and lubricity of fuels used to power the engine, the apparatus comprising:

• a fuel injection sensor adapted to communicate with an engine control unit (ECU) and to be positioned to sense fuel injection from a fuel injector into a combustion cylinder of the engine and to generate a sensed fuel injection signal in response thereto;
• and
• a program storable in a memory associated with the ECU, the program including:
• means to compute an actual fuel pulse in response to the sensed fuel injection signal, the actual fuel pulse, Ai, defined as the duration of the time interval that the fuel injector is actuated for injecting fuel into the combustion chamber, the time interval at least partially determined by the compressibility and lubricity of the fuel injected;
• means to compare the actual fuel pulse to a preselected desired fuel pulse, Di, the desired fuel pulse being defined as a desired duration for the fuel injector to be in an open position;
• means to compute a fuel pulse compensation factor, k, the compensation factor being defined by the difference obtained by subtracting the actual fuel pulse from the desired fuel pulse, Di−Ai, and means to cause the ECU to generate a command signal that is conveyed to a fuel injection controller in communication with the fuel injector, the command signal being based on the desired fuel pulse and compensation factor such that the command signal signals the injection controller to controllably release fuel for a pulse of duration Ci+1=Di+k, so that subsequent actual fuel pulses more closely correspond to the desired fuel pulse.

A program stored in a memory unit and adapted to be used by a processor in conjunction with fuel injector and fuel injection controller to control for variations in fuel injection timing in a compression ignition engine resulting from variability in the compressibility and lubricity of fuels used to power an engine, the program comprising:

• means to compute an actual fuel pulse in response to the sensed fuel injection signal, the actual fuel pulse, Ai defined as the duration of the time interval that the valve of the fuel injector is in an open position, the actual fuel pulse being a function of the time interval and the time interval at least partially determined by the compressibility and lubricity of the fuels used to power the engine;
• means to compare the actual fuel pulse to a preselected desired fuel pulse, Di, the desired fuel pulse being defined as a desired duration for the fuel injector to be in an open position;
• means to compute a fuel pulse compensation factor, k, the compensation factor being defined by the difference obtained by subtracting the actual fuel pulse from the desired fuel pulse, Di−Ai, and
• means to generate a command signal that is conveyed to a fuel injection controller in communication with the fuel injector, the command signal being based on the desired fuel pulse and compensation factor such that the command signal signals the injection controller to controllably release fuel for a pulse of duration Ci+1=Di+k, so that subsequent actual fuel pulses more closely correspond to the desired fuel pulse.

A method for controlling variations in fuel injection timing resulting from variability in the compressibility and lubricity of fuel used to power a compression ignition engine, the method comprising:

• sensing the actual rate at which fuel is injected into at least one cylinder of the engine;
• comparing the actual rate of fuel injection sensed with a fuel injection parameter indicating the desired rate of fuel injection;
• and
• changing the rate of fuel injection to thereby inject fuel at the desired rate.

A method for controlling variations in fuel injection timing resulting from variability in the compressibility and lubricity of fuels used to power an ignition compression engine, the method comprising:

• generating a first command signal, Ci;
• actuating a first fuel injection at a first fuel injection rate into a combustion chamber of the engine in response to the first command signal;
• determining a first injection value, Ai, having a correlation with the first fuel injection rate;
• comparing the first injection value, Ai, to a preselected injection parameter, Di, corresponding to a desired rate of fuel injection into the combustion chamber;
• generating a second command signal, Ci+1, in response to the comparison between the first injection value, Ai, and the injection parameter, Di;
• actuating a second fuel injection at a second fuel injection rate into the combustion chamber in response to the second command signal, Ci+1, yielding a second injection value, Ai+1, having a correlation with the second fuel injection rate such that the absolute value of the difference between the second injection value and the preselected injection parameter, |Ai+1−Di|, is less than or equal to the absolute value of the first injection value and the desired rate, |Ai−Di, so that |Ai+1−Di51 ≦|Ai−Di|.