Methods are provided for reducing exhaust gas emissions during a cold-start of an engine. In one example, a method may include generating a flame front in an exhaust port of an exhaust system, heating exhaust gas flowing into an emission control device of the exhaust system and thereby expediting the approach to a light-off temperature of the emission control device, and directing the flame front back to the cylinder as part of a combustion stroke of the four-stroke engine cycle.

Methods are provided for reducing exhaust gas emissions during a cold-start of an engine. In one example, a method may include generating a flame front in an exhaust port of an exhaust system, heating exhaust gas flowing into an emission control device of the exhaust system and thereby expediting the approach to a light-off temperature of the emission control device, and directing the flame front back to the cylinder as part of a combustion stroke of the four-stroke engine cycle.

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.

The present subject matter relates to a control unit for controlling an internal combustion engine, wherein the internal combustion engine includes at least one cylinder 100, at least one combustion chamber 90 within which a fuel is burned, at least one fuel injector 40, 50, at least one ignition device 60, and an oxygen determination unit 20 configured to determine the content of oxygen in the fuel, wherein the control unit 10 is configured to control the internal combustion engine based on the content of oxygen in the fuel detected by the oxygen determination unit 20.

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.

In an engine including an auxiliary chamber having an ignition plug therein, an amount of heat generated in the auxiliary chamber tends to be large, and thus it is necessary to suppress abnormal combustion. However, when a sensor is added to the ignition plug, a manufacturing cost of the ignition plug tends to increase. An ECU 2 includes an auxiliary chamber temperature estimation unit 21 that estimates a temperature of the auxiliary chamber 42, and an ignition control unit 22 that delays an ignition timing at a first decrease degree defined in accordance with a change amount of the ignition timing with respect to the temperature of the auxiliary combustion chamber as the temperature of the auxiliary chamber 42 increases in a case where the estimated temperature of the auxiliary chamber 42 is included in a middle temperature region equal to or lower than a first set temperature.

Provided is an internal combustion engine control device capable of reducing a measurement load and calculating a flow velocity around an ignition plug. The internal combustion engine control device includes an inter-gap voltage calculation unit 31 and a flow velocity calculation unit 32. The inter-gap voltage calculation unit 31 calculates a reference inter-gap voltage under a reference condition, based on a secondary current and in-cylinder pressure. The flow velocity calculation unit calculates the flow velocity of a gas around the ignition plug based on the reference inter-gap voltage.

Provided is an internal combustion engine control device capable of reducing a measurement load and calculating a flow velocity around an ignition plug. The internal combustion engine control device includes an inter-gap voltage calculation unit 31 and a flow velocity calculation unit 32. The inter-gap voltage calculation unit 31 calculates a reference inter-gap voltage under a reference condition, based on a secondary current and in-cylinder pressure. The flow velocity calculation unit calculates the flow velocity of a gas around the ignition plug based on the reference inter-gap voltage.

To suppress a failure of ignition of a fuel caused by a spark plug while suppressing wear of an electrode of the spark plug in an internal combustion engine. A control device 1 for an internal combustion engine includes an ignition control unit that controls energization of an ignition coil 300 that applies electric energy to a spark plug 200 that discharges in a cylinder 150 of an internal combustion engine 100 to ignite a fuel. The ignition control unit continuously transmits a first pulse signal (pulse signal for corona discharge) to an igniter connected to the ignition coil 300 before dielectric breakdown between electrodes of the spark plug 200, and continuously transmits a second pulse signal (pulse signal for arc discharge) to the igniter after the dielectric breakdown between the electrodes of the spark plug 200 to control the energization of the ignition coil 300. At this time, a period of the pulse signal for corona discharge is shorter than a period of the pulse signal for arc discharge.

In an engine including an auxiliary chamber having an ignition plug therein, an amount of heat generated in the auxiliary chamber tends to be large, and thus it is necessary to suppress abnormal combustion. However, when a sensor is added to the ignition plug, a manufacturing cost of the ignition plug tends to increase. An ECU 2 includes an auxiliary chamber temperature estimation unit 21 that estimates a temperature of the auxiliary chamber 42, and an ignition control unit 22 that delays an ignition timing at a first decrease degree defined in accordance with a change amount of the ignition timing with respect to the temperature of the auxiliary combustion chamber as the temperature of the auxiliary chamber 42 increases in a case where the estimated temperature of the auxiliary chamber 42 is included in a middle temperature region equal to or lower than a first set temperature.