According to one or more embodiments presently described, a method of operating an internal combustion engine that includes injecting fuel into a combustion chamber to form an air-fuel mixture, where the combustion chamber includes a cylinder head, cylinder sidewalls, and a piston that reciprocates within the cylinder sidewalls. The method may also include detecting pre-ignition of the air-fuel mixture during a detected intake or compression stroke of the piston, determining that a super knock condition could occur, and mitigating formation of a super knock condition by deploying a super knock countermeasure within the detected compression stroke.

A fuel injection control system may include a variable exhaust valve mechanism configured to primarily open an exhaust valve directly before an intake stroke in which an intake valve is opened and to secondarily open the exhaust valve during the intake stroke such that valve overlap occurs; an exhaust injector provided at an exhaust side to inject fuel; and a controller for controlling the exhaust injector such that fuel is injected through the exhaust injector before the exhaust valve is opened secondarily before or during the intake stroke.

The present disclosure relates to a method for braking of an internal combustion engine, in particular a four-stroke internal combustion engine. The method involves a partial opening of at least one gas discharge valve of at least one cylinder of the internal combustion engine during a compression stroke of the internal combustion engine. The method involves a holding of a partial opening of the at least one gas discharge valve during an expansion stroke of the internal combustion engine following the compression stroke and during an exhaust stroke of the internal combustion engine following the expansion stroke. The method involves a closing of the partly opened at least one gas discharge valve at the end of the exhaust stroke or during an intake stroke of the internal combustion engine following the exhaust stroke.

The invention relates to a method for assisted upshifting in a gear change of a transmission connected to a combustion engine. The method comprises the initiation of an upshifting process. The method comprises the reduction of an engine speed of the combustion engine by switching to an engine-braking mode, wherein a variable valve gear, in particular a trip cam system, of the combustion engine serves for switching to the engine-braking mode. Alternatively or in addition, in the engine-braking mode a first exhaust valve of the combustion engine is at first kept closed during the compression stroke and/or during the exhaust stroke for the compression of air and is opened before reaching a top dead centre of a piston movement for decompression of the compressed air.

A system includes an engine with a plurality of pistons housed in respective ones of a plurality of cylinders, an air intake system provides air to the plurality of cylinders through respective ones of a plurality of intake valves, an exhaust system to release exhaust gas from the plurality of cylinders through one of a plurality of exhaust valves, and a controller coupled to a sensor to control a switching tappet for compression release braking. Alternatively to a tappet, the system includes a roller finger follower controlling an opening and closing timing of exhaust valves, the roller finger follower has an inner roller follower arm adjacent an outer sliding follower, and a controller that in response to an engine braking request locks the inner roller follower arm with the outer sliding follower to contact a second cam lobe and open the exhaust valve during a compression stroke of the cylinder.

A device for reducing total hydrocarbon (THC) contained in exhaust gas in a CNG-diesel dual fuel engine system, includes: an engine providing power for the diesel and outputting exhaust gas due to operation; a MOC (Methane Oxidation Catalyst) oxidizing and discharging CH.sub.4 contained in exhaust gas discharged from the engine; an exhaust valve disposed in a pipe connecting the rear end of the engine and the front end of the MOC, and discharging the exhaust gas produced by the engine; a first temperature sensor disposed at the front end of the exhaust valve and measuring the temperature of exhaust gas coming from the engine; a second temperature sensor disposed at the rear end of the exhaust valve and measuring the exhaust gas discharged from the exhaust valve and flowing into the MOC; and an exhaust valve control unit increasing the temperature of exhaust gas flowing into the MOC.

A method for controlling the air-fuel ratio of a vehicle includes: calculating the air amount charged in a cylinder of an engine by using a fresh air amount, a residual air amount remaining inside the cylinder of the engine, and a backflow gas amount flowing back into the cylinder upon the valve overlap of an intake vale and an exhaust valve of the engine, correcting it with the purge gas flow rate supplied to an intake manifold of the engine when the active purge system is operated, calculating the final fuel amount by correcting the fuel amount injected by a fuel injection device with the amount of the fuel component contained in the purge gas when the active purge system is operated, and controlling the air-fuel ratio based on the final air amount and the final fuel amount.

A variable control method of exhaust temperature increase includes, when a cam phaser, which is connected to a double cam shaft having a coaxial arrangement structure of an outer shaft and an inner shaft, is operated and when a cam angle is determined as being varied by a controller, a cam phaser position change control is performed of decreasing a flow rate of an internal exhaust gas recirculation (EGR) supplied to a cylinder of an engine with a cam advance angle, increasing the flow rate of the EGR with a cam retard angle, or blocking the flow rate of the EGR with a maximal cam advance angle.

Aspects of the present disclosure are directed to an internal combustion engine having a valve actuation device and at least one first exhaust valve and one second exhaust valve per cylinder. The first and second exhaust valves may be actuated together in at least one operating area of the internal combustion engine, via an exhaust valve bridge and a first valve lifter, by a first cam lobe of a first exhaust cam arranged on a camshaft. The camshaft having a second exhaust cam with at least one additional cam lobe and at least one second cam lobe A transmission device being arranged in the functional path between the second exhaust cam and the second exhaust valve, the transmission device allowing an idle stroke to be activated or deactivated. The first exhaust cam and the second exhaust cam are configured and arranged to be rotatable relative to one another.

A fuel injection control system may include a variable exhaust valve mechanism configured to primarily open an exhaust valve directly before an intake stroke in which an intake valve is opened and to secondarily open the exhaust valve during the intake stroke such that valve overlap occurs; an exhaust injector provided at an exhaust side to inject fuel; and a controller for controlling the exhaust injector such that fuel is injected through the exhaust injector before the exhaust valve is opened secondarily before or during the intake stroke.