An internal combustion engine for a vehicle includes: an oil tank defining an oil reservoir; a pump to pump oil from the oil reservoir to lubricate parts of the engine; and a cyclonic separator disposed within the oil tank and configured to separate gas from oil received therein, the cyclonic separator defining an internal separator chamber for circulation of oil therein, the cyclonic separator comprising: a vortex forming portion configured to cause oil flowing therethrough within the internal separator chamber to define a spiral path in order to separate at least part of a gas content therefrom; an oil inlet for receiving oil into the internal separator chamber, the oil inlet being fluidly connected to the pump; an oil outlet for discharging oil from the internal separator chamber and into the oil reservoir of the oil tank; and a gas outlet for discharging gas from the internal separator chamber.

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.

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.

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.

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.

A device for damping torsional oscillations comprises a support rotatable around an axis. At least one pendulum body is movable with respect to the support. At least one bearing member interacts with at least one raceway integral with the support and with at least one raceway integral with the pendulum body. The bearing member rolls along each raceway around an inactive raceway position. The first region is shaped to filter a first order value of the torsional oscillations by the pendulum body when the bearing member rolls along that first region. Two second regions are beyond an end of the first region. Each second region is shaped to filter a second order value of the torsional oscillations by the pendulum body when the bearing member rolls along one of those second regions. The second order value is strictly lower than the first order value.

An engine unit support structure (1) which includes an engine unit (2) having a three-cylinder engine (22), a mount (3) for mounting the engine unit, and a plurality of elastic support bodies (4) coupled to the engine unit and the mount to support the engine unit, in which the plurality of elastic support bodies (4) has a plurality of first elastic support bodies (4A) and a plurality of second elastic support bodies (4B), the second elastic support bodies (4B) are so disposed as to be orthogonal to a pitching rotation central axis (22B) of the engine unit and astride a virtual plane (22D) including a rolling rotation central axis (22A) of the engine unit, and the first elastic support bodies (4A) are disposed in a position closer to the pitching rotation central axis (22B) than the second elastic support bodies (4B) and astride the virtual plane (22D).

A combined-cycle combustion control type three-cylinder engine includes: a cylinder block; and cylinders arranged in a row in the cylinder block and consisting of first, second, and third cylinders so that four-cycle combustion is performed in two of the first, second, and third cylinders and two-cycle combustion is performed in the remaining cylinder. A crankshaft is provided in first, second, and third pistons and converting reciprocating motions of the respective first, second, and third cylinders into rotational motions. A camshaft receives a rotational force from the crankshaft to control intake and exhaust timings for each of the first, second, and third cylinders.

The present invention relates to an internal-combustion engine comprising at least two cylinders wherein a piston in connection with a combustion chamber moves. Said combustion chamber comprises a single intake valve (SA), a single exhaust valve (SE), a single fuel injector (ID), two spark plugs (Al) and means for creating a swumble flow in said chamber.

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.