A method for controlling a marine engine's operating mode includes operating the engine in an initial operating mode according to an initial set of mapped parameter values configured to achieve an initial fuel/air equivalence ratio of an air-fuel mixture for combustion. If measured operating conditions of the engine meet lean-burn mode enablement criteria, the engine is operated in lean-burn mode according to a lean-burn set of mapped parameter values configured to achieve a lean-burn fuel/air equivalence ratio that is less than the initial fuel/air equivalence ratio. If the measured engine operating conditions no longer meet the lean-burn mode enablement criteria, the engine is operated in the initial operating mode. Transitions between the lean-burn mode and the initial operating mode are monitored. If the transitions indicate that the engine's operating mode is unstable, the engine is prevented from operating in the lean-burn mode until after a reset condition has been met.

A control device for a compression-ignition engine is provided, in which partial compression-ignition combustion including spark ignition (SI) combustion performed by combusting a portion of mixture gas inside a cylinder by spark-ignition followed by compression ignition (CI) combustion performed by causing the rest of the mixture gas inside the cylinder to self-ignite is executed within a part of an operating range of the engine. The device includes a detector configured to detect a parameter related to noise caused by the combustion inside the cylinder, an EGR (exhaust gas recirculation) controller configured to change an EGR ratio being a ratio of exhaust gas introduced into the cylinder, and a combustion controller configured to control the EGR controller to increase the EGR ratio when a noise index value specified based on the detected parameter of the detector is confirmed to exceed a given threshold during the partial compression-ignition combustion.

Provided is a control device for an engine comprising an engine whose combustion mode is switchable according to an engine operation state, wherein the control device is capable of controlling the engine while suppressing generation of knock noise due to abnormal combustion. The control device comprises: a basic target torque-determining part (61) configured to determine a basic target torque based on a vehicle driving state including manipulation of an accelerator pedal; a torque reduction amount-determining part (63) configured to determine a torque reduction amount based on a vehicle driving state other than the manipulation of the accelerator pedal; a final target torque-determining part (65) configured to determine a final target torque based on the basic target torque and the torque reduction amount; and an engine control part (69) configured to set the combustion mode to a premixed combustion mode or a diffusion combustion mode according to the engine operation state. The engine control part is configured, when the engine operation state changes from a diffusion combustion region to a premixed combustion region, due to a change in the final target torque corresponding to a change in the torque reduction amount, to maintain the combustion mode in the diffusion combustion mode.

A fuel injector for a combustion engine is disclosed. The fuel injector includes an injector body having a nozzle orifice, a solenoid coil mounted in the injector body, a control chamber filled with high-pressure fuel, an armature moved by electromagnetic force of the solenoid coil to vary fuel pressure in the control chamber, and a needle that moves to open or close the nozzle orifice according to the variation in the fuel pressure in the control chamber. The fuel injector further includes piezoelectric actuator for adjusting a fuel injection rate by adjusting an opening speed of the nozzle orifice based on a load condition of the engine.

A control system for a compression-ignition engine is provided, which includes the engine, a spark plug, a fuel injection valve, an air-fuel ratio control valve, and a control unit. A geometric compression ratio of the engine is 14:1 or above. The control unit includes a processor configured to execute an air-fuel ratio controlling module for, when the engine being in a given operating state is detected, controlling the air-fuel ratio control valve to bring the air-fuel ratio of the entire mixture gas to a given lean air-fuel ratio that is larger than a stoichiometric air-fuel ratio, and an spark plug controlling module for, after this control, outputting the control signal to the spark plug to perform the ignition at a given ignition timing so that the mixture gas starts combustion by flame propagation and then unburned mixture gas self-ignites. The given ignition timing is stored in a memory.

Embodiments for operating an engine with skip fire are provided. In one example, a method comprises during a skip fire mode or during a skip fire mode transition, port injecting a first fuel quantity to a cylinder of an engine, the first fuel quantity based on a first, predicted air charge amount for the cylinder and lean of a desired air-fuel ratio, and direct injecting a second fuel quantity to the cylinder, the second fuel quantity based on the first fuel quantity and a second, calculated air charge amount for the cylinder.

A conventional gasoline engine is retrofitted and calibrated to operate as a bi-fuel engine using Hydrogen as the second fuel. When operated with Hydrogen, which typically leads to a reduction of engine output power, the engine is preferably operated in a charged mode and in a lean mode with the engine throttle kept in a wide-open position during charged and lean mode operation resulting in a more efficient engine with a reduction of engine output power loss.

A remaining fuel amount warning device for a vehicle, the remaining fuel amount warning device giving a warning that an amount of fuel remaining in a fuel tank is smaller than a predetermined value on the basis of output of a fuel gauge measuring the remaining fuel amount, includes combustion state changing device for changing the combustion state of an engine. When the remaining fuel amount becomes smaller than the predetermined value, the remaining fuel amount warning device performs remaining amount warning control that produces vibration different than during normal operation by changing the combustion state of the engine by the combustion state changing device. A starter switch for starting the engine is made to serve also as a warning acknowledging button for stopping the remaining amount warning control for a predetermined time on the basis of an operation by an occupant.

An internal combustion engine system includes a control system with a monitoring mechanism producing data of engine operating state within a BMEP/speed envelope, and an electronic control unit structured to output a control command to vary at least one of a fuel delivery property or an air delivery property in the engine based on the data. Outputting the control command switches the engine between or among combustion modes that each satisfy different calibration criteria for optimizing aftertreatment function.

An engine having at least a primary and secondary fuel supplies is configured to operate by determining a fueling mode for each of first and second groupings of cylinders, independently. A method, therefore, for operating the engine includes monitoring engine operating parameters with an electronic controller, determining an engine operating point based on the engine operating parameters, calculating a first operating mode of a first cylinder grouping based on the engine operating point, calculating a second operating mode of a second cylinder grouping based on the engine operating point, and selectively activating at least one of a diesel injector, a gaseous fuel injector and a spark device in each engine cylinder separately and selectively for each cylinder of the first and second cylinder grouping based on the engine operating point.