An exhaust flow control system comprises a housing defining first and second passages that are fluidly connected to first and second scrolls of a twin scroll turbocharger and to a high pressure exhaust gas recirculation (HPEGR) system, a poppet valve configured to (i) in an open position, fluidly connect the first and second scrolls to each other and to the HPEGR system via the first and second passages and (ii) in a closed position, fluidly disconnect the first and second scrolls from each other and from the HPEGR system, and a controller configured to command the poppet valve to one of the open and closed positions based on one or more engine operating parameters thereby allowing the twin scroll turbocharger to operate in both a twin scroll mode and a mono scroll mode while also allowing for HPEGR control with minimal additional system volume.

An exhaust flow control system comprises a housing defining first and second passages that are fluidly connected to first and second scrolls of a twin scroll turbocharger and to a high pressure exhaust gas recirculation (HPEGR) system, a poppet valve configured to (i) in an open position, fluidly connect the first and second scrolls to each other and to the HPEGR system via the first and second passages and (ii) in a closed position, fluidly disconnect the first and second scrolls from each other and from the HPEGR system, and a controller configured to command the poppet valve to one of the open and closed positions based on one or more engine operating parameters thereby allowing the twin scroll turbocharger to operate in both a twin scroll mode and a mono scroll mode while also allowing for HPEGR control with minimal additional system volume.

A vehicle engine exhaust system with integrated exhaust gas recirculation (EGR) includes an exhaust manifold having multiple exhaust ports including a first exhaust port and a second exhaust port. The first exhaust port and the second exhaust port receive exhaust flow from a common exhaust split upstream of the first exhaust port and the second exhaust port. A valve assembly has a first butterfly valve positioned in the first exhaust port and a second butterfly valve positioned in the second exhaust port. A shaft is positioned within the exhaust manifold commonly connecting the first butterfly valve to the second butterfly valve to simultaneously rotate the first butterfly valve and the second butterfly valve.

An automobile vehicle engine exhaust system with integrated exhaust gas recirculation portion includes a cylinder head having a first exhaust passage internal to the cylinder head. The first exhaust passage is split within the cylinder head into a dedicated exhaust passage opening out of the cylinder head via a dedicated exhaust port, and an exhaust gas recirculation (EGR) exhaust passage opening out of the cylinder head via an EGR exhaust port. A valve assembly is operated to open one of the dedicated exhaust port or the EGR exhaust port while closing the other one of the dedicated exhaust port or the EGR exhaust port.

An automobile vehicle engine exhaust system with integrated exhaust gas recirculation portion includes a cylinder head having a first exhaust passage internal to the cylinder head. The first exhaust passage is split within the cylinder head into a dedicated exhaust passage opening out of the cylinder head via a dedicated exhaust port, and an exhaust gas recirculation (EGR) exhaust passage opening out of the cylinder head via an EGR exhaust port. A valve assembly is operated to open one of the dedicated exhaust port or the EGR exhaust port while closing the other one of the dedicated exhaust port or the EGR exhaust port.

Systems and methods are provided for controlling exhaust gas recirculation (EGR). In one example, an engine system includes a first EGR valve coupling an exhaust manifold to an engine exhaust system, a second EGR valve coupling the exhaust manifold to an engine intake system, and a control unit. The control unit selectively adjusts a position of the first EGR valve based on a target amount, and adjusts a position of the second EGR valve based on the target amount and a position of the first EGR valve. Responsive to a first degradation condition of the first EGR valve, the control unit adjusts the position of the second EGR valve based on the target amount and based on a pressure of the first exhaust manifold, and responsive to a second degradation condition of the first EGR valve, adjusts the position of the second EGR valve based on the target amount.

An internal combustion engine includes a cylinder head assembly having a first group of exhaust ports and a second group of exhaust ports as well as an exhaust manifold integrated with the cylinder head assembly. The exhaust manifold includes a first runner in fluid communication with the first group of exhaust ports. The first runner defines a first exit configured for directing exhaust gas from the first group of exhaust ports to an EGR bypass passage and further defines a second exit configured for directing exhaust gas from the first group of exhaust ports to a turbocharger passage. The engine further includes a bypass valve assembly mounted to the exhaust manifold and having a bypass valve disposed within the first runner. The bypass valve is moveable between a turbine-closed position and an EGR-closed position.

An internal combustion engine includes a cylinder head assembly having a first group of exhaust ports and a second group of exhaust ports as well as an exhaust manifold integrated with the cylinder head assembly. The exhaust manifold includes a first runner in fluid communication with the first group of exhaust ports. The first runner defines a first exit configured for directing exhaust gas from the first group of exhaust ports to an EGR bypass passage and further defines a second exit configured for directing exhaust gas from the first group of exhaust ports to a turbocharger passage. The engine further includes a bypass valve assembly mounted to the exhaust manifold and having a bypass valve disposed within the first runner. The bypass valve is moveable between a turbine-closed position and an EGR-closed position.

Various methods and systems are provided for estimating fresh intake air flow. In one example, a system comprises an engine having an intake manifold to receive fresh intake air and an exhaust gas recirculation (EGR) system to supply EGR to the intake manifold, where flow of EGR through the EGR system is controlled by one or more exhaust valves. The system further includes a controller configured to adjust a position of the one or more exhaust valves based on an estimated fresh intake air flow rate, where during a first set of operating conditions, the fresh intake air flow rate is estimated based on a total gas flow rate into the engine and further based on a current position of the one or more exhaust valves, intake manifold pressure, air-fuel ratio, and fuel flow to one or more cylinders of the engine.

Various methods and systems are provided for estimating fresh intake air flow. In one example, a system comprises an engine having an intake manifold to receive fresh intake air and an exhaust gas recirculation (EGR) system to supply EGR to the intake manifold, where flow of EGR through the EGR system is controlled by one or more exhaust valves. The system further includes a controller configured to adjust a position of the one or more exhaust valves based on an estimated fresh intake air flow rate, where during a first set of operating conditions, the fresh intake air flow rate is estimated based on a total gas flow rate into the engine and further based on a current position of the one or more exhaust valves, intake manifold pressure, air-fuel ratio, and fuel flow to one or more cylinders of the engine.