A method for detecting a damaged-bearing in an engine using a vibration signal may include: separating, by a controller, a vibration signal of the engine detected by a vibration detecting device installed on one side of the engine of a vehicle into a vibration signal caused by combustion knocking and a vibration signal generated in a bearing, extracting a signal in a predetermined natural frequency band from the vibration signal generated in the bearing using a band-pass filter, and processing the extracted signal to a quantified bearing signal using the controller, and comparing the quantified bearing signal with a preset damaged-bearing criterion using the controller to determine whether the quantified bearing signal is equal to or higher than the preset damaged-bearing criterion to determine a damage to the bearing.

A method for detecting a damaged-bearing in an engine using a vibration signal may include: separating, by a controller, a vibration signal of the engine detected by a vibration detecting device installed on one side of the engine of a vehicle into a vibration signal caused by combustion knocking and a vibration signal generated in a bearing, extracting a signal in a predetermined natural frequency band from the vibration signal generated in the bearing using a band-pass filter, and processing the extracted signal to a quantified bearing signal using the controller, and comparing the quantified bearing signal with a preset damaged-bearing criterion using the controller to determine whether the quantified bearing signal is equal to or higher than the preset damaged-bearing criterion to determine a damage to the bearing.

An actuator of a variable compression ratio mechanism for an internal combustion engine includes an arm link 13 configured to change a posture of the variable compression ratio mechanism for the internal combustion engine by swinging, a second control shaft 11 fixed to the arm link 13, and a housing 20 including a first bearing hole 301a supporting the second control shaft 11. The housing 20 includes a lubricant oil supply oil passage 202 opened to a pressure-receiving range over which a contact pressure is received at the first bearing hole 301a from the second control shaft 11 during an expansion stroke of the internal combustion engine.

An apparatus includes a connecting rod having a surface that defines an opening to receive a pin for coupling the connecting rod to a piston at a first end of the connecting rod. The surface includes a groove arrangement to collect, retain and distribute lubrication fluid in the space between the pin and the inner surface. The surface can be formed by the connecting rod or a bushing in an opening of the connecting rod.

An engine case includes bearings, an oil pump, lubricating oil passages, and a relief device. The bearings rotatably support a crankshaft and a camshaft. The oil pump and the lubricating oil passages are configured to pressure-feed lubricating oil to the bearings. The relief device is configured to adjust a pressure of the lubricating oil. The lubricating oil passages include main lubricating oil passages. The main lubricating oil passages include communication portions linearly formed with extending portions. The communication portions communicate between the respective bearings of the crankshaft and the camshaft from outside the engine case. The extending portions extend from outside the engine case to the bearing of the camshaft. The relief device is disposed having a relief valve and a relief hole at the extending portions.

A piston for a reciprocating-piston internal combustion engine includes a piston head and a piston skirt. The piston head has an encircling ring zone having at least one ring groove for a piston ring and an encircling cooling duct. In this case, the piston further includes at least one first bore starting from the cooling duct, the bore leading from the cooling duct to a bearing location of an upper connecting-rod bearing pin of the piston and opening into the bearing location in the form of a bore opening in order to supply the piston pin with lubricant from the cooling duct.

A device lubricates a connecting rod bearing on a crankshaft of an internal combustion engine. The device has a piston having an internal piston cooling fluid channel, and an outlet channel in fluid communication with the fluid channel. The device has a connecting rod, which is connected to the piston in an articulated, in particular pivotable, manner, and has a large connecting rod eye and a connecting channel. The large connecting rod eye is formed for receiving the connecting rod bearing. The connecting channel forms a fluid connection between the outlet channel and the large connecting rod eye so that a fluid, in particular a cooling lubricating fluid (e.g. oil), can be fed, or is fed, from the fluid channel to the large connecting rod eye via the outlet channel and the connecting channel. The connecting rod bearing can be lubricated by cooling oil from the fluid channel of the piston.

A device lubricates a big-end bearing on a crankshaft of an internal combustion engine. The device includes a piston with a fluid channel and an outlet channel fluidically connected thereto, and a connecting rod. The connecting rod has a small connecting rod eye, a large connecting rod eye and a connecting channel. The small connecting rod eye is fluidically connected to the outlet channel. The connecting channel forms a fluidic connection between the small and large connecting rod eyes so that a cooling lubricant fluid can be supplied from the fluid channel to the large connecting rod eye via the outlet channel, the small connecting rod eye and the connecting channel. In this way, the big-end bearing can be lubricated by cooling oil from the fluid channel of the piston.

A lubrication structure of the present invention is applied to a multi-link piston crank mechanism that has a upper link (3), a lower link (6) and a control link (7). Lubricating oil is supplied in an oil storing portion (21) formed between a pair of upper-pin pin boss portions (12) by a plate member (22) through an oil supply hole (19). By oscillating rotary motion of the upper link side pin boss portion (25) that is provided with an oil groove (29) on an end surface of the upper link side pin boss portion (25), the lubricating oil in the oil storing portion (21) is supplied to an upper pin (4).

A lubrication structure of the present invention is applied to a multi-link piston crank mechanism that has a upper link (3), a lower link (6) and a control link (7). Lubricating oil is supplied in an oil storing portion (21) formed between a pair of upper-pin pin boss portions (12) by a plate member (22) through an oil supply hole (19). By oscillating rotary motion of the upper link side pin boss portion (25) that is provided with an oil groove (29) on an end surface of the upper link side pin boss portion (25), the lubricating oil in the oil storing portion (21) is supplied to an upper pin (4).