Connecting rod for changing a compression ratio of an internal combustion engine

A connecting rod with a device for changing a compression ratio of an internal combustion engine, the connecting rod comprising:

• a connecting rod head and a connecting rod pin supported by an eccentric of the connecting rod at a variable distance from the connecting rod head, and an interlock, wherein
• a fluid chamber is defined inside the connecting rod head and contains a hydraulic fluid, the eccentric having a projection extending into the fluid chamber and in contact with the hydraulic fluid such that a fluid pressure of the hydraulic fluid in the fluid chamber exerts a force on the projection to change a position of the eccentric;
• and
• a hydraulic circuit in fluid communication with the fluid chamber and including a first sub-circuit for controlling the fluid pressure of the hydraulic fluid in the fluid chamber, a second sub-circuit de-coupled from the first sub-circuit for controlling the interlock, and a switching valve configured as a directional control valve with switching positions and ports, wherein in a locking position, the interlock inhibits rotation of the eccentric relative to the connecting rod head, and the interlock is configured to be releasable.

A connecting rod with a device for changing a compression ratio of an internal combustion engine, the connecting rod comprising:

• a connecting rod head and a connecting rod pin supported by an eccentric of the connecting rod at a variable distance from the connecting rod head, and an interlock, wherein
• a fluid chamber is defined inside the connecting rod head and contains a hydraulic fluid, the eccentric having a projection extending into the fluid chamber and in contact with the hydraulic fluid such that a fluid pressure of the hydraulic fluid in the fluid chamber exerts a force on the projection to change a position of the eccentric;
• and
• a hydraulic circuit in fluid communication with the fluid chamber and including a first sub-circuit for controlling the fluid pressure of the hydraulic fluid in the fluid chamber, a second sub-circuit de-coupled from the first sub-circuit for controlling the interlock, a switching valve configured as a directional control valve with switching positions and ports, and a hydraulic backstop, wherein in a locking position, the interlock inhibits rotation of the eccentric relative to the connecting rod head, the interlock is configured to be releasable, and the switching valve is actuated mechanically, hydraulically or electromagnetically.