A butterfly valve includes a body with a bore through which exhaust gas may flow and a valve member rotatably mounted within the bore for restricting flow through the bore. A stop extends into the bore to limit movement of the valve member and prevent the valve member from rotating to a closed position. The stop defines a restricted flow position at which the valve member is positioned between an open position and the closed position. An internal combustion engine utilizing the butterfly valve is also provided.

A butterfly valve includes a body with a bore through which exhaust gas may flow and a valve member rotatably mounted within the bore for restricting flow through the bore. A stop extends into the bore to limit movement of the valve member and prevent the valve member from rotating to a closed position. The stop defines a restricted flow position at which the valve member is positioned between an open position and the closed position. An internal combustion engine utilizing the butterfly valve is also provided.

Restrictors are disclosed that include a body defining a Venturi tube having a throat defining a junction of a converging inlet cone to a diverging outlet cone along a longitudinal axis thereof, and with the converging inlet cone and the diverging outlet cone each defining an inner passageway that transitions as a hyperbolic or parabolic function toward the throat.

Methods and systems are provided for cleaning out condensate stored at a charge air cooler. In response to increased condensate accumulation at a charge air cooler, airflow through the engine is increased to purge the condensate while an engine actuator is adjusted to maintain engine torque. Combustion stability issues of engine cylinders are addressed by adjusting fueling of each cylinder individually during condensate ingestion.

A method and internal combustion engine system are provided for keeping an exhaust gas aftertreatment system within its working temperature range during an idle or motoring engine operation mode of an internal combustion engine. The method includes sensing the temperature of the gas at the gas intake side of the internal combustion engine and/or of the exhaust gas; determining whether or not the sensed temperature value is in a predetermined temperature interval or below a predetermined temperature threshold; determining whether the internal combustion engine is in idle or motoring engine operation mode; in case the internal combustion engine is determined to be in an idle or motoring engine operation mode, controlling the temperature of the gas at the gas intake side of the internal combustion engine to be within the predetermined temperature range or below the predetermined temperature threshold by recirculating exhaust gas through a connecting duct by controlling at least one valve.

A number of variations may include a method including controlling low pressure EGR flow rates using air intake throttle with a variable swirl device or throttle valve, or using exhaust throttling.

A rate based model predictive controller and method for air path control for a diesel engine regulates intake manifold pressure (MAP) and EGR valve flow rate to specified set points by coordinated control of a variable geometry turbine (VGT) and EGR valve position. A decay and a flexible Lyapunov function is enforced on the rate based model predictive controller for a single step prediction and control arisen.

In an EGR system that introduces an EGR gas to a vicinity of an inlet of a compressor in an intake passage, prevention of erosion of an impeller by condensed water generated in an EGR passage, and restraint of pressure loss of intake air are made compatible. An introduction port for an EGR gas formed in a wall surface of the intake passage in a vicinity of the inlet of the compressor and an exhaust passage are connected by the EGR passage. The EGR passage is provided with an EGR valve, and an exhaust throttle valve is provided downstream of a position where the EGR passage is connected in the exhaust passage. By a control device that controls the EGR valve and the exhaust throttle valve, respective opening degrees of the EGR valve and the exhaust throttle valve are controlled in accordance with a flow rate of fresh air that flows to the compressor, and a velocity of the EGR gas that flows out into the intake passage from the introduction port for the EGR gas is changed so that the EGR gas flows toward a center portion of the impeller of the compressor.

Methods and systems are provided for controlling and coordinating control of a post-catalyst exhaust throttle and an EGR valve to expedite catalyst heating. By closing both valves during an engine cold start, an elevated exhaust backpressure and increased heat rejection at an EGR cooler can be synergistically used to warm each of an engine and an exhaust catalyst. The valves may also be controlled to vary an amount of exhaust flowing through an exhaust venturi so as to meet engine vacuum needs while providing a desired amount of engine EGR.

Methods and systems are provided for an Exhaust Gas Recirculation (EGR) system for an internal combustion engine. In one example, the EGR system comprises an inlet air duct configured to provide the internal combustion engine with inlet air, an EGR diffuser configured to provide recirculated exhaust gases from the internal combustion engine to the inlet air duct through an outlet, and a resilient element, the EGR diffuser and resilient element adapted to provide homogenous mixing of EGR gases and inlet air at a specific operating condition of the vehicle.