A method of heating a catalytic converter of an internal combustion engine, wherein the method comprises the steps of: igniting the gas charge in one of the cylinders in a range from 10? CA before ignition top dead center to 20? CA after ignition top dead center; and opening the exhaust valve of the cylinder exhaust of the cylinder in a range from 30? CA to 55? CA after ignition top dead center. The method allows the catalytic converter of the internal combustion engine to quickly reach operating temperature and thus contributes to the reduction of pollutant emissions. An internal combustion engine is also provided that is designed to carry out the method of the invention for heating a catalytic converter.

A method for carrying out a gas exchange in a cylinder of an internal combustion engine is provided. The cylinder is connected to a gas line section via a valve. An actuator adjusts a gas pressure in the gas line section. The valve closes at a fixed point in time in a working cycle of the internal combustion engine in case of a constant torque of the internal combustion engine. The method includes the steps of recognizing a torque change request; determining a target value for the gas pressure in the gas line section in dependence on the torque change request; and determining a variable point in time for closing the valve as a result of the torque change request, wherein the variable point in time is shifted in the working cycle relative to the fixed point in time in dependence on the target value of the gas pressure.

Methods and systems are provided for providing exhaust gas recirculation to a naturally aspirated internal combustion engine. In one example, exhaust gas is recirculated to an engine intake via a dedicated scavenging manifold and a scavenging exhaust valve. The exhaust gas and fresh air that has not participated in combustion may be recirculated to engine cylinders even at high engine loads since the exhaust gas and fresh air is returned to the engine air intake at a pressure greater than atmospheric pressure.

The control device 80 for an internal combustion engine comprises a control unit 81 configured to perform control processing comprising, during warming-up of the internal combustion engine 10, advancing valve opening timing and valve closing timing of an exhaust valve 18 of the internal combustion engine 10 with respect to respective preset reference values thereof, and retarding fuel injection timing of the internal combustion engine 10 with respect to a preset reference value thereof. According to this control device 80 for the internal combustion engine, warming-up of the internal combustion engine 10 can be effectively facilitated, and the warming-up time of the internal combustion engine 10 can thus be shortened.

A control apparatus for a compression autoignition engine includes an engine, a state quantity setting device, a spark plug, and a controller. After the spark plug ignites air-fuel mixture to start combustion, unburned air-fuel mixture is combusted by autoignition. The controller changes, according to an operation state of the engine, a heat amount ratio that represents an index associated with a ratio of an amount of heat generated by air-fuel mixture being combusted by flame propagation, to a total amount of heat generated by air-fuel mixture in the combustion chamber being combusted.

Methods and systems are provided for providing exhaust gas recirculation to a naturally aspirated internal combustion engine. In one example, exhaust gas is recirculated to an engine intake via a dedicated scavenging manifold and a scavenging exhaust valve. The exhaust gas and fresh air that has not participated in combustion may be recirculated to engine cylinders even at high engine loads since the exhaust gas and fresh air is returned to the engine air intake at a pressure greater than atmospheric pressure.

Methods and systems for adjusting exhaust valve timing of an engine are described. In one example, exhaust valve timing of a compression ignition engine is adjusted responsive to a difference between a commanded exhaust valve opening timing and an actual exhaust valve opening timing, the actual exhaust valve opening timing determined from cylinder pressure.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, a flow of exhaust (e.g., exhaust gas recirculation) from engine cylinders to the intake passage, upstream of a compressor, via an exhaust gas recirculation (EGR) passage and the first exhaust manifold may be adjusted by adjusting a timing of a first set of cylinder exhaust valves coupled to the first exhaust manifold. Additionally, the first set of cylinder exhaust valves open at a different time than a second set of cylinder exhaust valves coupled to the exhaust passage.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, an intake valve timing, exhaust valve timing of a first set of exhaust valves coupled to the first exhaust manifold, and a position of an exhaust gas recirculation (EGR) valve in an EGR passage may be adjusted in coordination with one another in response to a condition at a compressor. The EGR passage may be coupled between the intake passage, upstream of the compressor, and the first exhaust manifold.

Rich control is performed to hold an air-fuel ratio of an exhaust gas discharged from an engine combustion chamber temporarily richer than the stoichiometric air-fuel ratio by injecting additional fuel into a cylinder in an expansion stroke or exhaust stroke while an exhaust gas recirculation rate is made lower than a base exhaust gas recirculation rate. A variable valve timing mechanism able to change an overlap period is provided. When ending rich control (ta2), the injection of additional fuel is stopped and the overlap period (OL) is increased from a base overlap period (OLB) and held there while an EGR rate (REGR) is kept lower than a base EGR rate (REGRB) and when a delay time (dt) elapses, the EGR rate and the overlap period are reset to the base EGR rate and the base overlap period.