A system includes a control system configured to monitor operating conditions in at least a first cylinder of a reciprocating engine and to control the reciprocating engine, wherein the control system includes a first sensor configured to monitor a first type of operating condition of the first cylinder, and a controller communicatively coupled with the first sensor. The controller is configured to receive a first signal indicative of a first measurement of the first type of operating condition from the first sensor; analyze the first signal to detect a misfire condition in the first cylinder; derive an amount of residual gas in the first cylinder if the misfire condition is detected; and adjust control of the reciprocating engine based on the amount of residual gas.

An internal combustion engine, a method of operating the internal combustion engine, and a controller are disclosed. The method may be implemented in part by the controller and comprises determining a shaft angle of an engine shaft; supplying, to an ion sensor fluidly coupled to a combustion chamber of the engine a low voltage at a beginning of a combustion cycle to generate an ion sensor current and a high voltage during an ionization voltage window based at least in part on the shaft angle, wherein the low voltage is configured to prevent premature ignition of fuel in the combustion chamber and the high voltage exceeds the low voltage and is configured to increase the ion sensor current above a current threshold.

To provide a control device, of an internal combustion engine, that accurately identifies the combustion state through ion current detection in a wide operation range of the internal combustion engine, without impairing the reliability and the durability of the control device of the internal combustion engine. This internal combustion engine control device includes: an ignition plug having a center electrode and a ground electrode opposed to each other with a gap therebetween; a circulation device for short-circuiting a primary winding to cause a circulation route to enter a conduction state, thereby stopping spark discharge; and an ion-current-detection bias voltage control device for controlling bias voltage for ion current detection. The potential of the center electrode in an ion current detection period is controlled by adjusting the value of the bias voltage and the changing speed of the bias voltage.

The subject matter of this specification can be embodied in, among other things, a method that includes receiving a collection of measurements of electric current amplitude in a primary winding of an engine ignition system having the primary winding and a spark plug, identifying an ignition start time, identifying an inflection point based on the plurality of measurements, determining an inflection point time representative of a time at which the identified inflection point occurred, determining a spark start time based on an amount of time between the ignition start time and the inflection point time, and providing a signal indicative of the spark start time.

An electronic ignition system for an internal combustion engine. The system includes a coil having a primary winding with a first terminal and a second terminal and a secondary winding connected to a spark plug. A high voltage switch is serially connected to the primary winding. A control terminal carries a control signal to control the opening or closing of the high voltage switch. A first switch is interposed between a battery voltage and the first terminal of the primary winding, a second switch is interposed between the first terminal of the primary winding and a reference voltage, a third switch is interposed between the second terminal of the primary winding and said reference voltage. A driving unit is configured to generate signals to control the switches during a charging phase, during a transfer of energy phase, and during a measure phase of ionization current.

A control device for an internal combustion engine includes a knock control system, a cooling system, and an electronic control unit. The knock control system is configured to ignite a spark plug an ignition crank angle obtained by retarding the ignition crank angle in response to an occurrence of the knocking. The electronic control unit is configured to supply a command value corresponding to a target value of a cooling parameter to the cooling system such that the cooling system performs cooling of the internal combustion engine according to the command value. The electronic control unit is configured to correct the command value based on a KCS learned value such that as the KCS learned value increases, a correction amount for correcting the command value increases in correction amount in a direction in which a cooling capacity of the cooling system increases.

The present invention relates to a method of controlling a positive-ignition internal combustion engine, in which the ignition advance is controlled (CON) by means of an estimation (EST) of the distribution of the knock measurements (MEAS). This estimation (EST) makes it possible to determine, for these measurements (MEAS), a confidence interval (q.sub.min, q.sub.max) of a predetermined quantile of the distribution of the knock measurements (MEAS).

A system includes a control system configured to monitor operating conditions in at least a first cylinder of a reciprocating engine and to control the reciprocating engine, wherein the control system includes a first sensor configured to monitor a first type of operating condition of the first cylinder, and a controller communicatively coupled with the first sensor. The controller is configured to receive a first signal indicative of a first measurement of the first type of operating condition from the first sensor; analyze the first signal to detect a misfire condition in the first cylinder; derive an amount of residual gas in the first cylinder if the misfire condition is detected; and adjust control of the reciprocating engine based on the amount of residual gas.

A misfire determination device of an engine in which explosion occurs at unequal intervals, the engine including a plurality of cylinders and a crankshaft which is angularly displaced at a different angle between expansion strokes, is configured to calculate generated torque correlation amount correlated with generated torque, based on an angular position signal of the crankshaft, and perform misfire determination, based on an average value of the generated torque correlation amount in an interval less than one cycle of the engine, at an angular position of the crankshaft which is different from an angular position of the crankshaft at an ignition timing.

An unequal-interval combustion engine misfire-determination device determines whether a misfire has occurred in an unequal-interval combustion engine including a plurality of cylinders in which combustion occurs at unequal intervals. The misfire determination device includes: an unequal interval combustion fluctuation canceled value acquisition unit that acquires, based on a crank angle signal, an unequal interval combustion fluctuation canceled value which is a rotation speed in a section of 720m crank angle degrees including a predetermined determination angle position, where m is a natural number; an unequal interval combustion fluctuation manifested value calculation unit that calculates an unequal interval combustion fluctuation manifested value in which a fluctuation component attributable to unequal interval combustion is manifested, by removing the unequal interval combustion fluctuation canceled value; and a specific cylinder misfire determination unit that determines a misfire in a specific cylinder based on the unequal interval combustion fluctuation manifested value.