An engine controller includes an ignition timing control unit and a rich imbalance determining unit. The rich imbalance determining unit designates one of multiple cylinders as a subject cylinder for determination and executes lean active control that commands a smaller amount of fuel injection for the subject cylinder than for the other cylinders. The rich imbalance determining unit determines whether an air-fuel ratio of the subject cylinder deviates to be richer based on a rotational fluctuation amount of a crankshaft during the execution of the lean active control. The ignition timing control unit executes an advancement limiting process that limits advancement of the ignition timing by the knock control during the execution of the lean active control.

A method for monitoring an engine cylinder in an internal combustion engine includes, for each engine cycle, detection of the ionisation current generated in the cylinder in a predetermined time interval of a combustion cycle, generation of a signal representing the ionisation current and comparing a maximum value of the signal with a threshold value. Successively, the value of one or more parameters associated with the signal can be changed with respect to an equal number of corresponding reference values when the maximum value of the signal exceeds the threshold value, to reduce the maximum value of the signal in the time interval of a successive combustion cycle. The presence of water in the cylinder can be determined when the maximum value of the signal exceeds the threshold value for a predetermined first number of combustion cycles occurring within a predetermined period of time.

A fuel injection control apparatus including a microprocessor. The microprocessor is configured to perform calculating a target injection time, determining a first crank angle defining a start of fuel injection and a second crank angle defining an end of fuel injection, controlling a fuel injector in a first injection mode in which the fuel is injected for the first target injection time from a first time point corresponding to the first crank angle or a second injection mode in which the fuel is injected for the second target injection time from a second time point corresponding to a target crank angle, and the controlling including controlling the fuel injector so as to inject the fuel in an intake stroke in the first injection mode, while inject the fuel in a compression stroke in the second injection mode.

A system for harmonizing knock in a plurality of cylinders included in an engine, the system comprises a plurality of knock sensors, and a controller coupled to each of the plurality of knock sensors. The controller is configured to receive a plurality of cylinder knock values corresponding to each of the plurality of knock sensors, and receive an average knock value. The controller determines a cylinder spark timing offset value for each cylinder in the plurality of cylinders from the average knock value and the cylinder knock values. The controller determines an average spark timing offset value. The controller also determines an adjusted spark timing value for each of the plurality of cylinders by subtracting the average spark timing offset value from a spark timing value of each of the plurality of cylinders.

Methods and systems are provided for controlling a variable displacement engine (VDE) of a vehicle to adjust a power generated by the VDE based on a demand for power from an onboard AC power generator of the vehicle. In one example, a method for a vehicle includes, with an engine of the vehicle turned off, estimating a power draw of an external electrical device to be supplied power via an onboard generator of the vehicle, and starting the engine in a variable displacement engine (VDE) mode with a number of deactivated cylinders selected based on the estimated power draw.

Methods and systems are provided for controlling engine knock. In one example, a method may include decreasing intake valve lift at a first set of cylinders where knock is indicated and increasing intake valve lift at a second set of cylinders where knock is not indicated. A stoichiometric air-to-fuel ratio is thereby maintained.

A controller for an internal combustion engine includes processing circuitry. The processing circuitry performs a dither control process. The dither control process includes a first mode in which a cylinder serving as a rich combustion cylinder is sequentially changed and a second mode in which a specified cylinder is fixed as one of a rich combustion cylinder and a lean combustion cylinder. The processing circuitry selects the first mode or the second mode based on an operating point of the internal combustion engine.

Systems and methods for adjusting ignition timing to one or more cylinders of a variable displacement engine responsive to a knock indication are described herein. In one particular example, during a partial cylinder mode, ignition timing to one or more cylinders may be adjusted responsive to a knock indication based on the number of cylinders deactivated; whereas during the full cylinder mode, ignition timing for all cylinders are adjusted responsive to a knock indication. Thereby, the systems and methods described allow a larger partial cylinder operating window that has a benefit of enhancing a vehicle's fuel economy.

A system for harmonizing knock in a plurality of cylinders included in an engine, the system comprises a plurality of knock sensors, and a controller coupled to each of the plurality of knock sensors. The controller is configured to receive a plurality of cylinder knock values corresponding to each of the plurality of knock sensors, and receive an average knock value. The controller determines a cylinder spark timing offset value for each cylinder in the plurality of cylinders from the average knock value and the cylinder knock values. The controller determines an average spark timing offset value. The controller also determines an adjusted spark timing value for each of the plurality of cylinders by subtracting the average spark timing offset value from a spark timing value of each of the plurality of cylinders.

An auxiliary chamber (51) having a spark plug (54) and an auxiliary fuel injector is formed at the central part of the top surface of the main combustion chamber (2). When making an air-fuel mixture in the auxiliary chamber (51) burn by the spark plug (54), an air-fuel mixture in the main combustion chamber (2) is made to burn by jet flames ejected from the communicating holes (52). The injection ports of the auxiliary fuel injector (53) are oriented toward a tumble flow inflow peripheral region (R) which is located on the peripheral part of the end portion of the auxiliary chamber (51) at a place located on a side where the tumble flow W flows in from the communicating holes (52). When the tumble flow (W) is made to be generated in the main combustion chamber (2) by the tumble flow control valve (48), auxiliary fuel (QF) is injected from the auxiliary fuel injector (53) toward the tumble flow inflow peripheral region (R) of the auxiliary chamber (51).