Intake holes at the opposite ends are opened and closed by first intake valves. The middle intake hole is opened and closed by a second intake valve. A control device includes an intake variable valve device. First branch channels are connected to the intake holes and produce a normal tumble flow. A second branch channel is configured such that the flow rate of intake air passing through the middle intake hole is relatively greater on the side closer to the outer periphery of the combustion chamber. Where increasing the flow coefficient is given a higher priority, a three-valve drive mode is selected. Where the strength of the normal tumble flow is enhanced, a two-valve drive mode is selected. Where production of the normal tumble flow is reduced, a one-valve drive mode is selected.

A four-stroke reciprocating piston internal combustion engine is disclosed. The engine includes an even number of cylinders grouped into a first half and a second half. An exhaust gas turbocharger has a first turbine inlet and a second turbine inlet. Each of the cylinders has an intake duct with an intake opening, a first exhaust duct with a first exhaust opening, and a second exhaust duct with a second exhaust opening. The first half of cylinders is connected via the respective first exhaust ducts to the first turbine inlet and is connected via the second exhaust ducts to the second turbine inlet. The second half of cylinders is connected via the respective first exhaust ducts to the second turbine inlet and is connected via the respective second exhaust ducts to the first turbine inlet. The respective second exhaust openings have a larger diameter than the respective first exhaust openings.

An internal combustion engine includes an intake port configured to generate a swirl in a cylinder, an exhaust port, and a piston. The piston includes a top surface provided in an upper portion of the piston, a cavity provided from the top surface toward a lower portion of the piston around a central axis of the piston, and a connection surface connecting an inner edge of the top surface and an upper end of a side surface of the cavity to each other. The connection surface is provided to be closer to a lower portion side of the piston than the top surface. An area of the connection surface projected on a plane parallel to the top surface is larger on an intake port side than on an exhaust port side.

An internal combustion engine includes a first intake valve, a second intake valve, an accelerator open degree sensor that detects a load state, and an ECU 26 that controls the valve opening timing of the first and second intake valves and an amount of intake gas introduced to a combustion chamber from the first and second intake valves. When a load of a vehicle increases, the ECU reduces the ratio of the amount of intake gas from, among the two or more intake valves, the second intake valve having a later valve opening timing, whereas when the load decreases, the ECU increases the ratio.