An engine assembly including a crankshaft, a bell crank pivotally mounted on the crankshaft, the bell crank having a first end and a second end opposite of the first end, a connecting rod connected to the first end of the bell crank, a control shaft, a control link mounted on the control shaft and connected to the second end of the bell crank, a driven gear fixed to the crankshaft, a drive gear fixed to the control shaft, an actuator, and a split-torque gear box splitting the torque from the driven gear between the drive gear via a first torque path and the actuator via a second torque path.

Methods and systems are provided for adjusting a compression ratio. In one example, a system may include rotating an eccentric ring of a crankshaft by flowing hydraulic fluid to first and second chambers to actuate the eccentric ring.

A fastening structure (105) includes a pair of fastening members (105A) joined to each other, which is coupled with a bolt. The fastening member (105) is made of steel. A surface other than joint surfaces (Sa) has a Rockwell hardness of 50 HRC or more. The joint surfaces (Sa) have a Rockwell hardness of 30 HRC or more and less than 50 HRC. The joint surfaces (Sa) have an arithmetic mean roughness (Ra) of 0.2 m or more and 0.5 m or less. Production cost is suppressed, and at the same time, bending fatigue strength is secured and secondary damage due to abrasion powder generated by fretting is prevented.

A hypocycloidal internal combustion engine containing at least one alternative displacement piston connected through a connecting rod to a crankshaft, which is connected to an epicyclic gear train. In this gear train, the planet gear carrier is connected to the output shaft, and the ring gear can be rotated (in a controlled manner) in relation to the engine block. The present invention allows the control of the compression ratio and engine displacement of the engine by adjusting the angular position of the ring gear, which can be done continuously and instantaneously, even with the engine in operation.

A control method for an internal combustion engine is arranged to vary an engine compression ratio, and includes a control mechanism arranged to control the engine compression ratio, and a driving source arranged to drive the control mechanism. The control method includes converting an operation amount of the driving source in accordance with an attenuation rate according to the engine compression ratio, transmitting the converted operation amount to the control mechanism, and controlling the cylinder pressure based on a basic ignition timing when the attenuation rate is relatively large, and controlling the cylinder pressure based on an allowable ignition timing retarded from the basic ignition timing when the attenuation rate is relatively small.

Provided is a control device for an internal combustion engine capable of estimating a compression ratio of the internal combustion engine at the time of fuel cut of the internal combustion engine and without being affected by an intake air amount and an intake air temperature. A compression ratio is calculated on the basis of a change of in-cylinder pressure P with respect to crank angle at timing when an in-cylinder volume change rate dV/d/V takes an extreme value or at timing from closing of an intake valve 109 to the start of ignition of the air-fuel mixture in the cylinder.

Provided is a marine engine, including: a piston; and a compression ratio controller configured to execute lowering processing of moving a top dead center position of the piston toward a bottom dead center side when an engine rotation speed falls within a resonance occurrence range set in advance. A geometrical compression ratio is reduced, and a resonance stress caused by a torsional vibration in a rotary system can thus be suppressed while suppressing a decrease in thermal efficiency compared with a case in which retarding control is applied to a fuel injection timing or a closing timing of an exhaust valve.

A VCR apparatus may include a connecting rod at which a small end forming a hole having a circular shape to be rotatably connected with a piston pin moving together with the piston and a large end rotatably connected with a crank pin eccentrically arranged with respect to the crankshaft are formed; an eccentric cam concentrically arranged and rotatably disposed in the hole of the small end and configured so that the piston pin is eccentrically inserted thereinto and is rotatably connected therewith; a latching pin disposed in the small end to make a reciprocal rectilinear motion in a direction of rotation axis of the small end and operated to selectively latch the small end with the eccentric cam in one among at least two relative positions between the small end and the eccentric cam; and an acting oil passage formed at the connecting rod.

The method of providing an internal combustion engine with one or more variable sized combustion chambers providing pistons in the cylinders forming combustion chambers, providing the pistons with piston connecting rods which are pivotably connected to the pistons on one end and to floating pins on the second end, providing crankshaft connecting rods pivotably connected to rod journals on the crankshaft and to the floating pins on a second end, and moving the position of the crankshaft relative to the cylinders such that when the position of the crankshaft relative to the cylinders is changed, the operating characteristics of the engine are changed.

The method of providing an internal combustion engine with one or more variable sized combustion chambers providing pistons in the cylinders forming combustion chambers, providing the pistons with piston connecting rods which are pivotably connected to the pistons on one end and to floating pins on the second end, providing crankshaft connecting rods pivotably connected to rod journals on the crankshaft and to the floating pins on a second end, and moving the position of the crankshaft relative to the cylinders such that when the position of the crankshaft relative to the cylinders is changed, the operating characteristics of the engine are changed.