A method and diagnostic tool diagnoses a charge cycle behavior of an internal combustion engine with a plurality of cylinders. The method determines a diagnosis time window within a torque dropout of one of the cycles of the internal combustion engine, and associates a deviation type with the diagnosis time window determined.

An engine includes an output shaft, a cylinder head, a cylinder block, and a plurality of head bolts. The cylinder block includes three or more cylinder parts, a plurality of connecting portions, a plurality of output shaft supporting parts, and a plurality of head bolt holes. A side wall face of at least one cylinder part includes a first rib. The first rib diagonally extends from the connecting portion toward a head bolt hole base.

A powertrain system includes a port injection internal combustion engine. A first start process is a process in which fuel is enclosed in a compression stroke cylinder when the engine is stopped, and based on a stored crank stop position, ignition is performed in a first cycle of the compression stroke cylinder upon engine start. A second start process is a process in which, based on the stored crank stop position, fuel injection is performed for an intake stroke cylinder while the engine is stopped, and based on the stored crank stop position, ignition is performed in the first cycle of the intake stroke cylinder upon engine start. When a catalyst temperature at the time engine start is requested is equal to or higher than a first threshold, a control device starts the internal combustion engine by at least one of the first start process and the second start process.

In a cylinder head according to an example of the present disclosure, a pair of intake ports communicating with the common combustion chamber are formed so that the wall thickness of the port walls on opposing sides is relatively small and the wall thickness of the port walls on reversing sides is relatively large. Herein, the opposing side is the side on which the port walls of the pair of the intake ports face each other. The reversing side is the side opposite to the opposing side. That is, the reversing side is the side on which the port walls of the pair of the intake ports face away from each other. An inter-ports flow path for flowing the cooling water is formed between the port walls on the opposing sides of the pair of the intake ports.

An air intake apparatus includes a plurality of funnel-shaped portions provided in a plurality of intake ports. The plurality of funnel-shaped portions respectively include open ends located at positions at which lengths of the plurality of intake ports are aligned with each other, the open ends being provided along a direction perpendicular to a direction in which respective centerlines of the plurality of intake ports extend.

An internal combustion engine including at least two cylinders with parallel longitudinal axes, each cylinder including an opening and a piston capable of moving in translation inside the cylinder, the respective openings of the cylinders facing each other, the pistons being in kinematic relation with a connecting rod-crank mechanism including: a spacer connecting the pistons, suitable for maintaining a fixed spacing between the pistons, the pistons being respectively attached to the arms of the spacer, a crankshaft rotating about an axis, arranged between the openings of the cylinders and between the longitudinal axes of the cylinders, the crankshaft comprising a crank pin, a rocker rotating about the crank pin, at least one connecting rod including a first, small end, rigidly attached to the spacer and a second, big end, rigidly attached to one of the ends of the rocker.

An intake manifold according to an exemplary embodiment of the present invention may include a first intake manifold having a second intake pipe, a third intake pipe, and a first surge tank which temporarily stores intake air flowing through an intake line and distributes the intake air to the second intake pipe and the third intake pipe. A second intake manifold has a first intake pipe, a fourth intake pipe, and a second surge tank which temporarily stores intake air flowing through the intake line and distributes the intake air to the first intake pipe and the fourth intake pipe.

An airflow control valve structure includes a metallic pivot shaft-and a valve body. The valve body includes a connection portion connected to the pivot shaft and a resin valve portion. The pivot shaft includes first and second pivot shaft side press-fit portions. The connection portion includes a first valve side press-fit portion formed integrally with the valve portion and a metallic fitting member including a second valve side press-fit portion. The first valve side press-fit portion is fitted to the first pivot shaft side press-fit portion at an angular position at which a phase of the valve portion is matched with a phase of the pivot shaft. The second valve side press-fit portion is fitted to the second pivot shaft side press-fit portion. The first pivot shaft side press-fit portion is longer than the second valve side press-fit portion.

An exhaust manifold may include first to fourth exhaust pipes respectively connected to first to fourth cylinders which is sequentially disposed in an engine, the exhaust manifold may include a first exhaust manifold including the second exhaust pipe connected to the second cylinder and the third exhaust pipe connected to the third cylinder; a second exhaust manifold including the first exhaust pipe connected to the first cylinder, the fourth exhaust pipe connected to the fourth cylinder and the first exhaust pipe, and a recirculation valve apparatus mounted in the first exhaust pipe; wherein the second exhaust pipe and the third exhaust pipe are directly connected to a converter housing for mounting a catalytic converter in which purifies exhaust gas, and wherein the fourth exhaust pipe is connected to the first exhaust pipe at upstream of the recirculation valve, and the first exhaust pipe is directly connected to the converter housing.

A cylinder block for use in an internal combustion engine includes a first and second cylinder bores, a first and second cylinder bore liners, and a Siamese insert. The first and second cylinder bores are disposed adjacent to each other. The first and second cylinder bores each comprise a first cylinder bore wall and a second cylinder bore wall, respectively, and a shared cylinder bore wall. The first cylinder bore liner is disposed on a first inner surface of the first cylinder bore wall and the second cylinder bore liner is disposed on a second inner surface of the second cylinder bore wall. The Siamese insert is disposed in a top portion of the shared cylinder bore wall.