Methods and systems are provided for an exhaust-gas arrangement. In one example, a system may include a barrier dividing an intake passage into first and second portions to mitigate exhaust-gas recirculate mixing with charge air upstream of a compressor.

A combustion engine for a vehicle has an intake duct through which a fuel gas/air/exhaust gas mixture can be fed to a combustion unit of the combustion engine, and an exhaust gas recirculation system feeding in an exhaust gas from the combustion unit at an exhaust gas admission region to the gas fed to the combustion unit. A measuring device that determines the fuel gas/air/exhaust gas mass flow and the fuel gas/air/exhaust gas temperature is arranged in the intake duct upstream of the combustion unit and downstream of the exhaust gas admission region. A temperature sensor is arranged both in the exhaust gas recirculation system and in the intake duct, in each case upstream of the exhaust gas admission region, in addition to the measuring device, to determine a recirculated exhaust gas mass flow and/or an air mass flow fed to the combustion unit.

Methods and systems are provided for determining a dilution of recirculated gases, including blowthrough air, combusted exhaust gas, and fuel vapor, in a split exhaust engine. In one example, the dilution rate may be calculated using a feedforward model that includes determining a pressure differential across a region in an intake passage, mapped engine parameters such as gas temperature, and exhaust valve timing. Engine operations such as spark advance and fuel injection may be adjusted according to the modeled rate to reduce engine knock and improve combustion efficiency.

Methods and systems are provided for determining a dilution of recirculated gases, including blowthrough air, combusted exhaust gas, and fuel vapor, in a split exhaust engine. In one example, the dilution rate may be calculated using a steady state model based on temperature measurements from an intake region of the engine. The steady state model may be further used in combination with a feedforward model adapted to estimate engine dilution during engine transients as a correction factor.

An EGR control device includes: a drive unit, a basic opening degree deriving unit, a measurement unit, a memory unit, a correction opening degree deriving unit and a control unit. The drive unit varies an opening degree of an EGR valve. The basic opening degree deriving unit derives a basic EGR valve opening degree based on an operating condition of an engine. The measurement unit measures a temperature in the downstream side of a position of where EGR gas is recirculated in an intake passage. In the memory unit, information acquired in advance is stored. The information indicates a relationship between the opening degree and a temperature difference. The correction opening degree deriving unit derives a correction opening degree with reference to the information. The control unit controls the drive unit such that the opening degree of the EGR valve becomes a target EGR valve opening degree by correcting the basic EGR valve opening degree with the correction opening degree.

Methods and systems are provided for measuring exhaust gas recirculation (EGR) distribution among individual engine cylinders. In one example, a method may include fluidly coupling a plurality of intake runners of an engine to a vacuum pump, diverting a portion of intake charge gas from the intake runner to a gas composition sensor with the vacuum pump, measuring an oxygen concentration of the diverted intake charge portion with the gas composition sensor, and estimating an EGR concentration of the intake charge based on the measured oxygen concentration.

Methods and systems for providing exhaust gas recirculation to a two stroke opposed piston diesel engine are described. In one example, high and low pressure exhaust gas recirculation systems may be activated or deactivated in response to exhaust gas hydrocarbon concentration and particulate matter flow rate from the engine. In addition, operation of the low and high pressure exhaust gas recirculation systems may be responsive to an operating state of a supercharger compressor.

A valve control device controls an opening degree of a valve provided in an intake passage, an exhaust passage, or a passage connected one of these and includes an observed value acquisition unit, an inlet temperature acquisition unit, a target calculation unit, an equilibrium opening degree calculation unit, an observer, a correction opening degree calculation unit, an instruction opening degree calculation unit, and an output unit. The target calculation unit calculates an equilibrium state value and a target property value. The correction opening degree calculation unit calculates a correction opening degree by multiplying a gain matrix by a deviation vector including, a deviation between the equilibrium state value and the estimated state value and an integrated value of a deviation between the target property value and the estimated property value.

A supercharged internal combustion engine is provided that is capable of introducing EGR gas into an intake passage on an upstream side relative to a compressor. When a required WGV opening degree is less than a lower limit value WGVmin in a case in which introduction of EGR gas is started under a situation in which the temperature of an EGR valve is less than or equal to a predetermined value X1, the WGV opening degree is controlled during a protection time period T3 after introduction of EGR gas starts by using the lower limit value WGVmin as the required WGV opening degree.

A system and method to perform bypass actuation detection includes alternating control of a bypass valve within an exhaust gas recirculation (EGR) system of a vehicle to direct flow of gas through a cooler module or a bypass module within the EGR system. The method also includes determining a position of an EGR valve that directs the gas into the EGR system, and verifying operation of the bypass valve based on the position of the EGR valve.