The application relates to internal combustion engines, cylinder heads, exhaust passages, and shapes and configurations of the exhaust passages. The exhaust passage may have cross-sectional shapes formed by two limbs. The cross-sectional shape of the exhaust passage may change as the passage extends. The exhaust passage may also merge with other exhaust passage. The exhaust passage may be part of a cylinder head or an exhaust manifold.

A method and system for assembling a vehicle of a family of vehicles includes providing a group of engines. A first engine including a first number of cylinders corresponds to a first vehicle. A second engine including a second number of cylinders corresponds to a second vehicle. The second number is greater than the first number which is at least one. A cylinder plane extends vertically and longitudinally. At least one cylinder is disposed at least partly forward of a front wheel plane. The transmission assembly is rearward of the selected engine and one of the transmission assembly and the selected engine is in a same location whether the selected engine is the first or the second. The seat is at least in part longitudinally rearward of the transmission assembly. The selected engine is laterally disposed between the centers of the footrests.

A cylinder block assembly has: a cylinder block having three cylinders aligned side-by-side; and four crank caps arranged side-by-side in an alignment direction of the cylinders and fastened to the cylinder block. The crank caps and the cylinder block are provided with crank bearings which rotatably support a crankshaft. The crank caps are arranged at both sides of each cylinder in the alignment direction. Intermediate crank caps positioned at intermediate positions in the plurality of the crank caps include removed parts so as to more easily deform when receiving a load from the crankshaft compared with the side crank caps.

An internal combustion engine includes: a cylinder block including a bulkhead formed so as to separate adjacent cylinders; a crankshaft including a counterweight; and a gas-vent hole which is formed in the bulkhead within a radius of rotation of the counterweight when seen from below a piston bottom-dead-center position and an axial direction of the crankshaft, and which communicates between the adjacent cylinders. The counterweight includes at least one of a concave portion and a through-hole formed at at least a part of a region of the counterweight opposed to the gas-vent hole during rotation of the crankshaft. The concave portion hollows in a direction away from the gas-vent hole, the through-hole penetrating through the counterweight in a direction away from the gas-vent hole.

Methods and systems are provided for a close-coupled aftertreatment device. In one arrangement, a system may include an engine comprising separate first and second overall exhaust lines, where a blow-off line branches off of the second overall exhaust line, and where the close-coupled aftertreatment device is arranged in the blow-off line and configured to receive exhaust gases during at least a cold-start of the engine.

A pendulum type mount system includes a pair of upper mounts that mount upper portions of a powerplant unit on a vehicle body, and a pair of first and second lower torque rods. The first and second lower torque rods are located on opposite sides to each other with respect to a reference plane including a gravity center of the powerplant unit. A first spring constant of the first lower torque rod is not smaller than a second spring constant of the second lower torque rod. A distance between a first plane including the first lower torque rod and the reference plane is not larger than a distance between a second plane including the second lower torque rod and the reference plane.

An internal combustion engine includes first and second power cylinders and an expander cylinder, and is configured to operate in an expander mode and a bypass mode by selectively fluidly coupling exhaust flow from the first and second power cylinders to the expander cylinder. Operation includes commanding a transition from the bypass mode to the expander mode, including retarding openings of intake valves of the first and second power cylinders to a LIVC position. Exhaust valves of the power cylinders are controlled to effect fluid flow to the expander cylinder, and opening of an outlet valve of the expander cylinder is controlled to a maximum advanced state. The openings of the intake valves of the first and second power cylinders are controlled to desired positions associated with engine operation in the expander mode.

An internal combustion engine includes: three or more cylinders including cylinders A, B and C according to the present disclosure arranged in a row in the cylinder row direction; and a balancer device for reducing engine vibration. The balancer device includes a balancer shaft arranged so as to extend from the cylinder A to the cylinder C along the cylinder row direction in a crank chamber. The balancer shaft includes: a first opening formed on the outer surface of the balancer shaft at a first location associated with the cylinder A in the cylinder row direction; a second opening formed on the outer surface at a second location associated with the cylinder C in the cylinder row direction; and a communication passage formed inside the balancer shaft so as to connect the first opening with the second opening.

A pendulum type mount system includes a pair of upper mounts that mount upper portions of a powerplant unit on a vehicle body, and a pair of first and second lower torque rods. The first and second lower torque rods are located on opposite sides to each other with respect to a reference plane including a gravity center of the powerplant unit. A first spring constant of the first lower torque rod is not smaller than a second spring constant of the second lower torque rod. A distance between a first plane including the first lower torque rod and the reference plane is not larger than a distance between a second plane including the second lower torque rod and the reference plane.

An internal combustion engine for a vehicle and a method for assembling an internal combustion engine. The engine includes a crankcase; a crankshaft disposed at least in part in the crankcase; a cylinder block connected to the crankcase, the cylinder block defining at least one cylinder; at least one piston operatively connected to the crankshaft and disposed in a corresponding cylinder; an oil tank defining an oil reservoir configured to contain oil therein; and a dry-sump lubrication system comprising a pump module for circulating oil throughout the engine. The pump module includes a pump shaft rotatable about a pump shaft axis; at least one pressure pump mounted to the pump shaft and configured to pump oil from the oil tank; and at least one scavenge pump mounted to the pump shaft and configured to draw oil from a respective part of the engine.