Various methods and systems are provided for adjusting a flow of exhaust gas in an exhaust gas recirculation system. In one embodiment, a method for an engine comprises controlling a flow of exhaust gas through an exhaust gas recirculation system of an engine system based on a choke level of a turbocharger. For example, the flow of exhaust gas in the exhaust gas recirculation system may be reduced to within a threshold of a choke level of the turbocharger, in response to an ambient condition.

An intake apparatus includes an intake apparatus body including a plurality of intake pipes and a distribution passage including a gas passage before branching which includes a first gas passage through which the external gas flows in a first gas flow direction and a second gas passage through which the external gas flows in a second gas flow direction, the second gas passage curving relative to the first gas passage at a downstream, and a gas passage after branching including a third gas passage branched in the first gas flow direction relative to the second gas passage and a fourth gas passage branched in an opposite direction from the first gas flow direction relative to the second gas passage, an angle formed between the second gas passage and the third gas passage is smaller than an angle formed between the second gas passage and the fourth gas passage.

An engine assembly may include an engine block, a first piston, a second piston, and a cylinder head. The first piston may be located in a first cylinder bore and the second piston may be located in a second cylinder bore. The cylinder head may be coupled to the engine block and cooperate with the first cylinder bore and the first piston to define a first combustion chamber and with the second cylinder bore and the second piston to define a second combustion chamber. The cylinder head may define a first intake and exhaust port arrangement in communication with the first combustion chamber and may define a second intake and exhaust port arrangement in communication with the second combustion chamber. The second intake and exhaust port arrangement may include a greater total number of ports than the first intake and exhaust port arrangement.

An engine assembly may include an engine block, a first piston, a second piston, and a cylinder head. The first piston may be located in a first cylinder bore and the second piston may be located in a second cylinder bore. The cylinder head may be coupled to the engine block and cooperate with the first cylinder bore and the first piston to define a first combustion chamber and with the second cylinder bore and the second piston to define a second combustion chamber. The cylinder head may define a first intake and exhaust port arrangement in communication with the first combustion chamber and may define a second intake and exhaust port arrangement in communication with the second combustion chamber. The second intake and exhaust port arrangement may include a greater total number of ports than the first intake and exhaust port arrangement.

Methods and systems are provided for indicating water at an oxygen sensor based on power consumption of a heating element of the oxygen sensor. In one example, water may be indicated at an oxygen sensor positioned in an intake of an engine responsive to power consumption of the heating element of the oxygen sensor increasing above a baseline level. Engine operating parameters may then be adjusted based on the water indication and the power consumption.

Methods and systems are provided for indicating water at an oxygen sensor based on power consumption of a heating element of the oxygen sensor. In one example, water may be indicated at an oxygen sensor positioned in an intake of an engine responsive to power consumption of the heating element of the oxygen sensor increasing above a baseline level. Engine operating parameters may then be adjusted based on the water indication and the power consumption.

A system includes an internal combustion engine having a number of cylinders, with at least one of the cylinders plumbed to have a complete recycle of the exhaust gases from the cylinder. The system further includes the completely recycled cylinder having an EGR stroke cycle, and the non-recycled cylinders of the engine having an exhaust stroke cycle. The system includes the EGR stroke cycle being distinct from the exhaust stroke cycle. An amount and composition of the exhaust gases from the recycled cylinder are distinct from the amount and composition of the exhaust gases from the non-recycled cylinders, at least at certain operating conditions of the engine.

An engine system is disclosed for use with an engine having at least a first cylinder and a second cylinder. The engine system may have a first exhaust manifold fluidly connected to the first cylinder, a second exhaust manifold fluidly connected to the second cylinder, and a recirculation passage extending from the first exhaust manifold to at least one of the first and second cylinders. The engine system may also have a restricted orifice connecting the first exhaust manifold to the second exhaust manifold, a pressure relief passage extending from the first exhaust manifold, and a valve disposed within the pressure relief passage and movable to selectively reduce a back pressure of the first exhaust manifold.

An engine system is disclosed for use with an engine having at least a first cylinder and a second cylinder. The engine system may have a first exhaust manifold fluidly connected to the first cylinder, a second exhaust manifold fluidly connected to the second cylinder, and a recirculation passage extending from the first exhaust manifold to at least one of the first and second cylinders. The engine system may also have a restricted orifice connecting the first exhaust manifold to the second exhaust manifold, a pressure relief passage extending from the first exhaust manifold, and a valve disposed within the pressure relief passage and movable to selectively reduce a back pressure of the first exhaust manifold.

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.