A mixer for a gas flow system, such as an exhaust gas recirculation system, is provided. In one example, a gas flow system for an engine includes a first passage through which a first gas is configured to flow along a first axis; a second passage through which a second gas is configured to flow along a second axis, the first passage fluidly coupled to the second passage at an outlet of the first passage; and a mixer integrated with the first passage at the outlet and extending into the second passage, the mixer including an extension extending radially around the first axis and a main body extending into the second passage along the first axis.

An exhaust gas recirculation structure includes an EGR cooler and an EGR duct, and the EGR duct includes an inflow portion into which the exhaust gas flowing out from the EGR cooler flows, a flow path, and an outflow portion from which the exhaust gas flows out. The flow path is provided such that the height on the side of the inflow portion is lower than the height on the side of the outflow portion, and has a region in which the distance between the center line of a flow path cross section of the flow path and a line along the lowest end in the height direction gradually increases from the outflow portion side toward the inflow portion side.

An exhaust gas recirculation structure includes an EGR cooler and an EGR duct, and the EGR duct includes an inflow portion into which the exhaust gas flowing out from the EGR cooler flows, a flow path, and an outflow portion from which the exhaust gas flows out. The flow path is provided such that the height on the side of the inflow portion is lower than the height on the side of the outflow portion, and has a region in which the distance between the center line of a flow path cross section of the flow path and a line along the lowest end in the height direction gradually increases from the outflow portion side toward the inflow portion side.

An intake device for an engine is provided which can inhibit excessive cooling of EGR gas. In the intake device including an intake passage, an EGR passage, and an EGR cooler, the intake passage is provided with a lateral-side intake passage portion provided on one side of an engine body in a vehicle width direction, the EGR passage is provided with a downstream-side EGR passage portion defining the EGR passage on a downstream side of the EGR cooler and provided on the one side of the engine body in the vehicle width direction, and the downstream-side EGR passage portion is disposed such that at least a portion thereof is positioned rearward of the lateral-side intake passage portion and overlaps with the lateral-side intake passage portion when seen from the front of a vehicle.

An imbalance detection device is provided. An obtainment process includes obtaining a rotation waveform variable based on a detection value of a sensor that detects a rotational behavior of a crankshaft, and an air-fuel ratio detection variable in each of a plurality of first intervals. A calculation process includes calculating an imbalance variable based on an output of a mapping having a value obtained by the obtainment process as an input. The imbalance variable indicates a degree of variations in an air-fuel ratio of the internal combustion engine. The rotation waveform variable indicates a difference between instantaneous speed variables that are variables corresponding to the rotational speed of the crankshaft in each of the second intervals.

An engine EGR system is provided, which includes an engine body, an intake passage, an exhaust passage and an EGR passage configured to recirculate exhaust gas as EGR gas to the intake passage. The EGR passage includes an EGR cooler and an EGR internal passage constituting the EGR passage upstream of the EGR cooler, and including a passage passing through a cylinder head. The EGR internal passage has a bent pipe part including a first bent portion at which an upstream portion of the EGR internal passage is bent away from a gas inflow port of the EGR cooler, a second bent portion located downstream of the first bent portion and bending the EGR internal passage toward the gas inflow port, and an intermediate portion connecting the first and the second bent portions by being disposed therebetween. The water-cooling passage is disposed around the bent pipe part.

An engine EGR system is provided, which includes an engine body, an intake passage, an exhaust passage and an EGR passage configured to recirculate exhaust gas as EGR gas to the intake passage. The EGR passage includes an EGR cooler and an EGR internal passage constituting the EGR passage upstream of the EGR cooler, and including a passage passing through a cylinder head. The EGR internal passage has a bent pipe part including a first bent portion at which an upstream portion of the EGR internal passage is bent away from a gas inflow port of the EGR cooler, a second bent portion located downstream of the first bent portion and bending the EGR internal passage toward the gas inflow port, and an intermediate portion connecting the first and the second bent portions by being disposed therebetween. The water-cooling passage is disposed around the bent pipe part.

An internal combustion engine includes combustion chambers, each having a first intake port, and first and second exhaust ports. An intake manifold is connected to the first intake port of each combustion chamber, a main pressure booster upstream of the intake manifold. An exhaust discharge arrangement includes a main exhaust manifold connected to the first exhaust port of each combustion chamber, the exhaust discharge arrangement connected to the second exhaust port of a first subset combustion chambers, and an exhaust recirculation manifold connected to the second exhaust port of a second subset combustion chambers and connected to an upstream side of the main pressure booster. The engine operates in high load and low load modes, which vary how the engine evacuates the exhaust gas of the second subset combustion chambers to the exhaust recirculation manifold. A related method is also disclosed.

An internal combustion engine includes combustion chambers, each having a first intake port, and first and second exhaust ports. An intake manifold is connected to the first intake port of each combustion chamber, a main pressure booster upstream of the intake manifold. An exhaust discharge arrangement includes a main exhaust manifold connected to the first exhaust port of each combustion chamber, the exhaust discharge arrangement connected to the second exhaust port of a first subset combustion chambers, and an exhaust recirculation manifold connected to the second exhaust port of a second subset combustion chambers and connected to an upstream side of the main pressure booster. The engine operates in high load and low load modes, which vary how the engine evacuates the exhaust gas of the second subset combustion chambers to the exhaust recirculation manifold. A related method is also disclosed.

Provided is a control device for an internal combustion engine that includes: a water-cooled cooler (intercooler) arranged at at least one of a portion of an intake air passage located on the upstream side of an intake port and an EGR passage; and a water pump configured to supply a cooling water with the cooler. The control device is configured: to execute a water supply operation that supplies the cooling water with the cooler by actuating the water pump when its execution condition which includes a requirement that a cooler temperature is higher than a cooling water temperature is met during stop of the internal combustion engine; and not to execute the water supply operation when the cooler temperature is lower than or equal to the cooling water temperature during stop of the internal combustion engine.