Methods and systems are provided for adjusting a throttle based on an intake oxygen sensor output. In one example, a method may include adjusting a position of a throttle based on a dilution threshold and a total aircharge dilution level, the total dilution aircharge level based on an output of an intake oxygen sensor. Additionally, spark timing may be adjusted based on the total aircharge dilution level.

An internal combustion engine includes a direct injection valve that directly inject gaseous fuel from an injection hole into a cylinder by separating a needle from a seat, and a blow-by gas treating device that recirculates blow-by gas from a crankcase to an intake passage. The control device executes a suction process of suctioning gas in the cylinder into an injection hole of the direct injection valve when the blow-by gas is being recirculated by the blow-by gas processing device.

An internal combustion engine includes a direct injection valve that directly inject gaseous fuel from an injection hole into a cylinder by separating a needle from a seat, and a blow-by gas treating device that recirculates blow-by gas from a crankcase to an intake passage. The control device executes a suction process of suctioning gas in the cylinder into an injection hole of the direct injection valve when the blow-by gas is being recirculated by the blow-by gas processing device.

A method for injecting nitrogen into an internal combustion engine cylinder includes moving a piston back and forth in a cylinder and injecting pure nitrogen into a combustion chamber during the compression stroke. The method includes injecting the fuel and nitrogen into different regions to create a stratified gas environment, igniting the fuel, and releasing exhaust emissions. An engine system for injecting nitrogen into an internal combustion engine includes a cylinder, a first intake line, one or more nitrogen injectors, and a fuel injector. An engine system for injecting nitrogen into an internal combustion engine includes a cylinder, an intake line, and a multi-nozzle injector with a fuel nozzle and a nitrogen nozzle.

A controller configured to control a gas mixing device and/or a port injection valve and a direct fuel injector of an internal combustion engine in order to: in a first operation mode, supply a first gaseous fuel to at least one main combustion chamber of the internal combustion engine via at least one intake valve, in a second operation mode, supply a second gaseous fuel to the at least one main combustion chamber of the internal combustion engine by use of the direct fuel injector, wherein a supply system for providing flushing gas to the direct fuel injector is provided and the controller is configured to activate the direct fuel injector during operation according to the first operation mode, such that the flushing gas is injected into the at least one main combustion chamber.