An opposed-piston engine with two crankshafts includes a first power transducer coupled to a first crankshaft of the two crankshafts and a second power transducer coupled to a second crankshaft of the two crankshafts. The two crankshafts are not rotatably connected, and so are free to rotate independently of each other. Phase relationships between the crankshafts may be controlled by operating the power transducers to increase, or reduce, crankshaft torque. Changes in crankshaft phase relationships cause changes in opposed piston locations, which, in turn, enable control of engine performance factors.

Provided is an actuator for a variable compression ratio mechanism of an internal combustion engine, which improves productivity. The actuator for a variable compression ratio mechanism of an internal combustion engine includes an electric motor; a control shaft to which a rotative force from the electric motor is transmitted, the control shaft including a first journal portion and a second journal portion; an arm link portion that is disposed between the first journal portion and the second journal portion in an axial direction and extends from the control shaft in a radial direction, where the axial direction is a direction along a rotational axis line of the control shaft, and the radial direction is a radiation direction of the rotational axis line, the arm link portion being linked to the variable compression ratio mechanism of the internal combustion engine; a first housing including an accommodation chamber that accommodates the arm link portion, a radial opening portion that opens from the accommodation chamber in the radial direction, and a first opening portion that opens from the accommodation chamber toward the first journal portion side in the axial direction; and a second housing that closes the first opening portion, the second housing including a first bearing portion that supports the first journal portion.

Methods and systems are provided for estimating an actual compression ratio of an engine cylinder based on the electric current applied to an actuator of the associated variable compression ratio mechanism. The compression ratio is estimated as a function of both a value and a location, relative to cylinder piston position, of a peak holding current applied by an electric motor on the actuator to maintain the actuator at a commanded compression ratio setting. In this way, the vehicle control system may more accurately infer the current actual compression ratio of each cylinder.

A hybrid vehicle includes an internal combustion engine and a motor generator, wherein the internal combustion engine includes a variable compression ratio mechanism structured to vary in mechanical compression ratio depending on variation in position of a compression ratio control member structured to move due to driving of an electric actuator. A control method for the hybrid vehicle includes: measuring a state of charge of a battery connected to the motor generator; and in response to regenerative operation of the motor generator in a state that the state of charge of the battery is equal to or higher than a predetermined level, consuming generated electric power by driving the electric actuator of the variable compression ratio mechanism.

A variable compression device includes a piston rod, a first fluid chamber configured to move the piston rod in a direction in which a compression ratio is increased by supplying a pressurized working fluid thereto, a regulation member configured to regulate movement of the piston rod in a direction in which a compression ratio is increased, a second fluid chamber provided between the piston rod and the regulation member and configured to store the working fluid, a supply flow path configured to guide the working fluid supplied to the second fluid chamber, a discharge flow path configured to guide the working fluid discharged from the second fluid chamber, and a flow rate regulation unit provided in the discharge flow path and configured to regulate a flow of the working fluid when the piston rod approaches the regulation member.

An internal combustion engine variable operation system includes: an intake-side variable valve mechanism for controlling an opening timing and a closing timing of an intake valve of an internal combustion engine; an exhaust-side variable valve mechanism for controlling an opening timing and a closing timing of an exhaust valve of the internal combustion engine. At a cold start of the internal combustion engine, the exhaust-side variable valve mechanism sets the opening timing of the exhaust valve advanced at or close to a midpoint between top dead center and bottom dead center, and sets the closing timing of the exhaust valve advanced at a first preset advance-side point before top dead center, and the intake-side variable valve mechanism sets the opening timing of the intake valve retarded at a first preset retard-side point after top dead center.

An internal combustion engine variable operation system includes: an intake-side variable valve mechanism for controlling an opening timing and a closing timing of an intake valve of an internal combustion engine; an exhaust-side variable valve mechanism for controlling an opening timing and a closing timing of an exhaust valve of the internal combustion engine. At a cold start of the internal combustion engine, the exhaust-side variable valve mechanism sets the opening timing of the exhaust valve advanced at or close to a midpoint between top dead center and bottom dead center, and sets the closing timing of the exhaust valve advanced at a first preset advance-side point before top dead center, and the intake-side variable valve mechanism sets the opening timing of the intake valve retarded at a first preset retard-side point after top dead center.

The invention relates to a length-adjustable connecting rod for a reciprocating piston engine, to a reciprocating piston engine, and to a vehicle having a reciprocating piston engine, wherein the connecting rod has a second connecting rod part with a guide cylinder, and a first connecting rod part with a guide shank, wherein the guide shank is accommodated by the guide cylinder and is movable relative thereto for adjustment of an effective connecting rod length, wherein the first connecting rod part has a first stop surface and the second connecting rod part has a second stop surface, wherein lying of the first stop surface against the second stop surface restricts a relative movement between the first connecting rod part and the second connecting rod part in a first direction, and wherein, when the first stop surface lies against the second stop surface, at least a portion of a compressive force acting on the connecting rod along the longitudinal axis of the connecting rod is transferred past the guide shank via the first stop surface and the second stop surface from the first connecting rod part into the second connecting rod part and/or vice versa.

An internal combustion engine and a method of controlling an internal combustion engine are provided, that are more efficient than existing engines. The internal combustion engine includes a combustion chamber, and the engine is configurable to operate in: a compressionless operating mode where the engine is driven by combustion of fuel and oxidant in the combustion chamber without compression of the fuel and oxidant; and a compression generating operating mode where the engine is used to compress fluid in the combustion chamber.

A variable compression ratio engine includes an extra chamber formed at a cylinder head, an extra valve being able to open/close the extra chamber, and an actuator being able to open/close the extra chamber by driving the extra valve.