Abstract: A pressure-based piston top-dead-center (“TDC”) position measurement system is disclosed, comprising: a fuel injector configured to inject fuel into a combustion chamber bounded in part by the piston; and a controller configured to control the fuel injector to cause a fuel injection when the piston is at each of a plurality of different positions relative to TDC while ensuring fuel is provided to the fuel injector at a substantially constant pressure. The controller is further configured to estimate a pressure in the combustion chamber in response to each fuel injection, fit a curve to the estimated pressures, and determine a TDC position of the piston as correlating with a maximum pressure on the curve.

Abstract: At least some embodiments of present disclosure direct to a fuel injection timing drift detection and/or compensation system. In some cases, the system collects or receives a series of fuel pressure data measured by one or more fuel pressure sensors. The system is configured to receive an indication of fuel flow cutout and a start-of-injection command signal. The system calculates a set of pressure drops using the series of fuel pressure data and identifies a selected pressure drop greater than a predetermined threshold to determine a measured start-of-injection timing based on the selected pressure drop. The system is further configured to evaluate whether a fuel injection drifting occurs based on received start-of-injection command signal and the measured start-of-injection timing. In some cases, the fuel injection drifting is used to either compensate fuel injection timing or raise a flag indicating the drifting.

Abstract: At least some embodiments of present disclosure direct to a fuel injection timing drift detection and/or compensation system. In some cases, the system collects or receives a series of fuel pressure data measured by one or more fuel pressure sensors. The system is configured to receive an indication of fuel flow cutout and a start-of-injection command signal. The system calculates a set of pressure drops using the series of fuel pressure data and identifies a selected pressure drop greater than a predetermined threshold to determine a measured start-of-injection timing based on the selected pressure drop. The system is further configured to evaluate whether a fuel injection drifting occurs based on received start-of-injection command signal and the measured start-of-injection timing. In some cases, the fuel injection drifting is used to either compensate fuel injection timing or raise a flag indicating the drifting.

Abstract: A system includes a reciprocating piston engine configured to output torque to drive a load. The system includes an engine speed sensor operatively coupled with the engine and configured to output an engine speed signal. The system includes an electronic control system operatively coupled with the powertrain. The electronic control system is configured to determine an engine acceleration in response to the engine speed signal, and detect a misfire of the engine in response to the engine acceleration.

Abstract: A system includes a reciprocating piston engine configured to output torque to drive a load. The system includes an engine speed sensor operatively coupled with the engine and configured to output an engine speed signal. The system includes an electronic control system operatively coupled with the powertrain. The electronic control system is configured to determine an engine acceleration in response to the engine speed signal, and detect a misfire of the engine in response to the engine acceleration.

Abstract: Methods and systems are provided for controlling fuel injectors of an engine. In one example, a system for an engine includes a fuel injector couplable to at least one engine cylinder; and a controller operatively couplable to the fuel injector. The controller is configured to during a first engine cycle, control injection of both a primary pulse of fuel and a pilot pulse of fuel into the at least one engine cylinder via the fuel injector, determining, for the at least one engine cylinder, an amount of adjustment to the primary pulse of fuel, the pilot pulse of fuel, or both the primary and the pilot pulse, and during a second engine cycle, following the first engine cycle, adjusting an amount of the primary pulse of fuel, the pilot pulse of fuel, or both based at least in part on the first response to the pilot pulse of fuel.

Abstract: Various methods and systems are provided for diagnosing a condition of a fuel injector of an engine. In one example, a method for an engine includes injecting a first pulse of fuel as a first pilot injection into a first subset of cylinders of a plurality of engine cylinders, where the first pilot injection precedes a primary injection of fuel into the first subset of cylinders by a duration; correlating a first response in an engine operating parameter to the first pilot injection; and adjusting the primary injection of fuel into the first subset of cylinders based on the first response. In one example, the first pilot injection precedes the primary injection by a predefined short duration and the primary injection of fuel is adjusted within a predefined or preset upper limit and lower limit.

Abstract: Various methods and systems are provided for diagnosing a condition of a fuel injector of an engine. In one example, a method for an engine includes injecting a first pulse of fuel as a first pilot injection into a first subset of cylinders of a plurality of engine cylinders, where the first pilot injection precedes a primary injection of fuel into the first subset of cylinders by a duration; correlating a first response in an engine operating parameter to the first pilot injection; and adjusting the primary injection of fuel into the first subset of cylinders based on the first response. In one example, the first pilot injection precedes the primary injection by a predefined short duration and the primary injection of fuel is adjusted within a predefined or preset upper limit and lower limit.

Abstract: Various methods and systems are provided for diagnosing a condition of a fuel injector of an engine. In one example, a method for an engine includes injecting a first pulse of fuel as a first pilot injection into a first subset of cylinders of a plurality of engine cylinders, where the first pilot injection precedes a primary injection of fuel into the first subset of cylinders by a duration; correlating a first response in an engine operating parameter to the first pilot injection; and adjusting the primary injection of fuel into the first subset of cylinders based on the first response. In one example, the first pilot injection precedes the primary injection by a predefined short duration and the primary injection of fuel is adjusted within a predefined or preset upper limit and lower limit.

Abstract: Various methods and systems are provided for diagnosing a condition of a fuel injector of an engine. In one example, a method for an engine includes injecting a first pulse of fuel as a first pilot injection into a first subset of cylinders of a plurality of engine cylinders, where the first pilot injection precedes a primary injection of fuel into the first subset of cylinders by a duration; correlating a first response in an engine operating parameter to the first pilot injection; and adjusting the primary injection of fuel into the first subset of cylinders based on the first response. In one example, the first pilot injection precedes the primary injection by a predefined short duration and the primary injection of fuel is adjusted within a predefined or preset upper limit and lower limit.

Abstract: Various methods and systems are provided for health assessments of a fuel system. In one example, a fuel system includes a low-pressure pump operable to pump fuel from a fuel source at a first pressure, a high-pressure pump operable to increase the first pressure to a second pressure, a valve positioned between the low-pressure pump and the high-pressure pump and operable to control fuel flow to the high-pressure pump, a common fuel rail fluidly coupling the high-pressure pump to a plurality of fuel injectors coupled to cylinders of an engine, and a controller. The controller is operable to adjust an amount of valve electrical current supplied to the valve to reach a commanded pressure of the common fuel rail during cylinder firing conditions, the supplied valve electrical current adjusted based on a valve pre-firing correction factor for the valve obtained based on valve electrical current prior to cylinder firing commencing.

Abstract: Various methods and systems are provided for diagnosing an engine component based on a measured engine speed during an engine shutdown event. As one embodiment, a method for an engine includes measuring an engine speed drop rate, via an engine speed sensor, during an engine shutdown event; and indicating a change in performance of one of the engine speed sensor or an additional engine component in response to the measured engine speed drop rate deviating from a reference engine speed drop rate by a pre-set or pre-defined threshold rate.

Abstract: Various methods and systems are provided for diagnosing an engine component based on a measured engine speed during an engine shutdown event. As one embodiment, a method for an engine includes measuring an engine speed drop rate, via an engine speed sensor, during an engine shutdown event; and indicating a change in performance of one of the engine speed sensor or an additional engine component in response to the measured engine speed drop rate deviating from a reference engine speed drop rate by a pre-set or pre-defined threshold rate.

Abstract: Various methods and systems are provided for diagnosing a condition of a fuel injector of an engine. In one example, a method for an engine includes injecting a first pulse of fuel as a first pilot injection into a first subset of cylinders of a plurality of engine cylinders, where the first pilot injection precedes a primary injection of fuel into the first subset of cylinders by a duration; correlating a first response in an engine operating parameter to the first pilot injection; and adjusting the primary injection of fuel into the first subset of cylinders based on the first response. In one example, the first pilot injection precedes the primary injection by a predefined short duration and the primary injection of fuel is adjusted within a predefined or preset upper limit and lower limit.

Abstract: Various methods and systems are provided for health assessments of a fuel system. In one example, a fuel system includes a low-pressure pump operable to pump fuel from a fuel source at a first pressure, a high-pressure pump operable to increase the first pressure to a second pressure, a valve positioned between the low-pressure pump and the high-pressure pump and operable to control fuel flow to the high-pressure pump, a common fuel rail fluidly coupling the high-pressure pump to a plurality of fuel injectors coupled to cylinders of an engine, and a controller. The controller is operable to adjust an amount of valve electrical current supplied to the valve to reach a commanded pressure of the common fuel rail during cylinder firing conditions, the supplied valve electrical current adjusted based on a valve pre-firing correction factor for the valve obtained based on valve electrical current prior to cylinder firing commencing.