Methods and systems are provided for adjusting a substitution ratio based on water in a combustion mixture of a multi-fuel engine. In one example, a method includes adjusting a substitution ratio in response to an amount of water provided to a multi-fuel engine configured to combust a first fuel and a second fuel, the second fuel different than the first fuel.

A fuel injection control device and a fuel injection control method for an internal combustion engine according to the present invention correct a basic pulse width by a cylinder-specific correction value that is based on injection variations among fuel injection valves to specify a cylinder-specific pulse width, determine whether or not a split number is acceptable based on a minimum pulse width and a pulse width per one injection calculated from the cylinder-specific pulse width and the split number to modify the split number based on a result of the acceptance determination, modify an acceptance determination reference value which is used in the acceptance determination based on the correction value for each cylinder, and execute split injection based on the split number, the basic pulse width, and the correction value for each cylinder.

Methods and systems are provided for re-combustion of exhaust in a cylinder of a multi-cylinder engine in order to increase the temperature of the exhaust for enhancing catalytic conversion within the multi-cylinder engine. In one example, a method may include expelling combusted gases from the cylinder into an intake manifold via an intake valve during an exhaust stroke, in order to rebreathe in the combusted gases from the intake manifold via the intake valve in a subsequent intake stroke.

Methods and systems are provided for an engine for adjusting cylinder parameter settings to optimize engine output during a transient mode. In one example, a method may include adjusting cylinder parameter settings, including a cam timing setting, a spark timing setting, and a fuel injection timing setting based on a chamber temperature in response to a rate of fuel injection acceleration being greater than a positive threshold, thus indicating the engine is in the transient mode.

A housing defines a gaseous fuel inlet and a gaseous fuel outlet. A rotor defines an internal flow passage therethrough that rotates with the rotor to, alternately, allow gaseous fuel flow, or to block gaseous fuel flow, between the inlet and the outlet, based on a position of the rotor. A seal is biased to abut an exterior surface of the rotor. The seal is between the rotor and the outlet. An actuator is rotably coupled to the rotor. The driver is configured to rotate the rotor. A controller is in communication with the driver and is configured to control the driver to rotate at a rate based on an engine speed of the engine.

Systems and methods for operating an engine that is started via expansion stroke combustion are described. In one example, the method increases air flow through the engine during an engine stopping process so that a larger amount of air may be trapped in a cylinder that is on its expansion stroke so that greater amounts of engine torque may be provided during engine starting.

An air-assisted jet flame ignition device includes a housing, a fuel-air premixing unit, and a prechamber. The fuel-air premixing unit includes a fuel injector, an air injection valve, a premixing sleeve, a premixing sleeve inner core placed in the premixing sleeve, and a fuel injector fastening bolt. An inner wall surface of the premixing sleeve and an outer wall surface of the premixing sleeve inner core form a premixing sleeve inner cavity. An inner wall surface of the premixing sleeve inner core, a lower end surface of a nozzle of the fuel injector, and an upper end surface of an air inlet of the air injection valve form a premixing cavity. The premixing cavity coupled to the premixing sleeve inner cavity via a through hole on the sidewall of the premixing sleeve inner core. A prechamber nozzle is fixedly coupled to the lower part of the housing.

Methods and systems for flex fuel engines that have both port fuel injection and direct injection. Operating an engine system includes determining a percent of ethanol in a fuel and determining whether the percent of ethanol is greater than a predetermined threshold. When the percent of ethanol is greater than the predetermined threshold, fuel is supplied only through the direct injection injectors. When the percent of ethanol is not greater than the predetermined threshold, fuel is supplied through a combination of the direct injection injectors and port fuel injection injectors.

Methods and systems for flex fuel engines that have both port fuel injection and direct injection. Operating an engine system includes determining a percent of ethanol in a fuel and determining whether the percent of ethanol is greater than a predetermined threshold. When the percent of ethanol is greater than the predetermined threshold, fuel is supplied only through the direct injection injectors. When the percent of ethanol is not greater than the predetermined threshold, fuel is supplied through a combination of the direct injection injectors and port fuel injection injectors.

A control method is provided for controlling an internal combustion engine for a vehicle configured to engage a lockup clutch during a fuel cut, and to decrease a lockup hydraulic pressure at a fuel cut recovery to bring the lockup clutch to a slip engagement. The control method includes estimating a torque of the internal combustion engine generated by the fuel cut recovery when a fuel cut recovery condition is satisfied. The control method further includes decreasing a decrease amount of the lockup hydraulic pressure as the torque is greater.