A residual gas ignitor for use in igniting a fuel-air mixture within a main combustion chamber of an engine. The residual gas ignitor includes at least one inlet/outlet port, a residual gas ignitor chamber for receiving a combustion gas from the main combustion chamber, an ignitor valve for opening and closing the at least one inlet/outlet port, an actuator for actuating the ignitor valve to open and close the at least one inlet/outlet port, a valve guide for keeping the ignitor valve in a correct orientation within the residual gas ignitor, a preload spring for being in compression when the actuator disposes the ignitor valve into the closed position, and a heating element for maintaining or increasing a temperature of the combustion gas while the combustion gas is in the residual gas ignitor chamber. The residual gas ignitor may be used in engines for initiating combustion of fuel-air mixtures.

A method for operating a compression ignition engine includes forming a combustible mixture by mixing generally homogeneously a first fuel and air and introducing this mixture into the at least one cylinder, compressing the combustible mixture with the piston in a compression stroke, injecting a second fuel to the combustible mixture at an injection-time of the second fuel during the compression stroke but before start of combustion, and continuing the compression stroke until combustion starts at those locations in the at least one cylinder where concentration of the second fuel is highest and/or the temperature of the mixture is the highest. Emission of the cylinder and/or mechanical stress of the cylinder caused by the combustion are monitored, and if emissions and/or mechanical stress are above respective predetermined thresholds, individually for the cylinder, the amount and/or the timing of the second fuel injected, and/or temperature of the cylinder charge is changed.

A valve train system for an internal combustion engine includes an exhaust valve moveable between an exhaust closed position and an exhaust open position. A camshaft includes a main exhaust lobe for moving the exhaust valve between the exhaust closed position and the exhaust open position for expelling exhaust constituents from the combustion chamber and an exhaust rebreath lobe for moving the exhaust valve between the exhaust closed position and the exhaust open position for allowing exhaust constituents into the combustion chamber. A two-step device is provided for transmitting motion from the camshaft to the exhaust valve and is switchable between a motion transmitting position and a motion preventing position such that the motion transmitting position allows motion to be transmitted from the exhaust rebreath lobe to the exhaust valve and the motion preventing position prevents motion from being transmitted from the exhaust rebreath lobe to the exhaust valve.

Methods and systems are provided for a hydrogen combustion engine. In one example, a method may include operating the hydrogen combustion engine at one of two combustion air ratios, wherein a combustion air ratio between the two is avoided via adjusting one or more operating parameters.

A residual gas ignitor for use in igniting a fuel-air mixture within a main combustion chamber of an engine. The residual gas ignitor includes at least one inlet/outlet port, a residual gas ignitor chamber for receiving a combustion gas from the main combustion chamber, an ignitor valve for opening and closing the at least one inlet/outlet port, an actuator for actuating the ignitor valve to open and close the at least one inlet/outlet port, a valve guide for keeping the ignitor valve in a correct orientation within the residual gas ignitor, a preload spring for being in compression when the actuator disposes the ignitor valve into the closed position, and a heating element for maintaining or increasing a temperature of the combustion gas while the combustion gas is in the residual gas ignitor chamber. The residual gas ignitor may be used in engines for initiating combustion of fuel-air mixtures.

An engine system is provided, including a controller which estimates an intake-valve-closing temperature inside a cylinder. When an engine operates at a given speed and a demanded engine load is a first load or a second load (>the first load), the controller controls so that a mixture gas inside the cylinder combusts by compression ignition, and controls so that, at the first load, the entire mixture gas combusts by compression ignition when the intake-valve-closing temperature is above a first temperature, and at least part of the mixture gas combusts by flame propagation when the intake-valve-closing temperature is below the first temperature, whereas at the second load, the entire mixture gas combusts by compression ignition when the intake-valve-closing temperature is above a second temperature (<the first temperature), and at least part of the mixture gas combusts by flame propagation when the intake-valve-closing temperature is below the second temperature.

An engine system is provided, including a controller which controls devices of an engine at a given engine speed so that, when a demanded engine load is a first load, a mass ratio (G/F) of intake air inside a cylinder (containing fresh air and burnt gas) to fuel is a first G/F and mixture gas inside the cylinder combusts by flame-propagation, when the demanded load is a second load (<the first load), the G/F is a second G/F (>the first G/F) and an injection center-of-gravity is at a timing such that the entire mixture gas combusts by CI combustion, and when the demanded load is between the first and second loads, the G/F is at a third G/F (between the first and second G/Fs) and the injection center-of-gravity is at a later timing such that at least part of the mixture gas combusts by the CI combustion.

The present disclosure relates to a method for operating an internal combustion engine (IO). The method includes generating a pressure pulse in an exhaust gas system of the internal combustion engine (IO). The method also includes supplying exhaust gas from a combustion chamber of a cylinder during an exhaust outlet stroke of the cylinder into an inlet channel of the cylinder by propagating the pressure pulse from the exhaust gas system into the combustion chamber of the cylinder. The method further includes supplying the exhaust gas from the inlet channel of the cylinder into the combustion chamber of the cylinder during an intake stroke of the cylinder. By means of internal residual gas control (residual exhaust gas control), the method permits the exhaust gas temperature to be raised in at low load without negatively influencing the full load performance of the internal combustion engine (IO).

A method of two-step variable valve lift (VVL) malfunction avoidance learning control may include: in a two-step VVL system which is operated with a main lift and a secondary lift, verifying, by an electronic control unit (ECU), an operation avoidance area based on locking of a lock pin of a cam follower ; performing VVL operation learning, in which a failure of occurrence of the second lift is determined on the basis of a locking failure of the cam follower due to an initially set value of the operation avoidance area; and reflecting the operation avoidance area to the two-step VVL system with a corrected set value which is obtained through the VVL operation learning.

A method of two-step variable valve lift (VVL) operation learning control for a vehicle may include: applying, by a lift controller, a VVL control to an electric two-step VVL system; determining, by the lift controller, whether the vehicle is running in an electric vehicle (EV) mode; and when the vehicle is running in the EV mode, performing, by the lift controller, a learning time securing control of allowing a VVL operation learning to be performed by engine operating for an operation avoidance area and an operation avoidance time which are applied to a secondary lift of an exhaust valve.