An engine includes a cylinder head including a first oil path and a second oil path. The cylinder head includes a valve gear including a first support and a second support that support a rocker shaft. The first support includes, on its outer surface, a first constriction located at an inlet of a connection-switching third oil path and connected to the first oil path, and a second constriction connected to the second oil path. The second support includes, on its outer surface, a third constriction connected to the first oil path, and a fourth constriction located at an inlet of a lubrication fourth oil path and connected to the second oil path.

Systems and methods for intermittent supply of lubricating oil to a tip of a rocker arm assembly. In one embodiment, a lubricating oil may be selectively to a tip of a rocker arm via oil channels aligned only during opening of a valve coupled to the tip.

Systems and methods for intermittent supply of lubricating oil to a tip of a rocker arm assembly. In one embodiment, a lubricating oil may be selectively to a tip of a rocker arm via oil channels aligned only during opening of a valve coupled to the tip.

There is provided a lubricating structure for a power transmission mechanism in which a crankshaft is coupled to a piston disposed in a cylinder bore and in which power is transmitted from the crankshaft to a camshaft. The lubricating structure includes: an idler gear that is configured to transmit power from the crankshaft to the camshaft; and an idler gear shaft that supports the idler gear via a bearing. One end portion of the idler gear shaft protrudes into the cylinder bore, and an oil passage configured to guide oil from the cylinder bore to the bearing is formed in the idler gear shaft.

Disclosed herein is a system includes a lubricated component and a lubricant pump that selectively provides lubricant to the lubricated component. The system also includes a lubricant source in lubricant providing communication with the lubricant pump. Additionally, the system includes a lubricant flow regulation device in lubricant receiving communication with the lubricated component and lubricant providing communication with the lubricant source. The lubricant flow regulation device is configured to drain lubricant from the lubricated component to the lubricant source based on when the lubricant pump provides lubricant to the lubricated component, and to prevent drainage of lubricant from the lubricated component to the lubricant source based on when the lubricant pump stops providing lubricant to the lubricated component.

A continuous variable valve timing apparatus may include a camshaft, a cam device on which a cam is formed respectively and of which the camshaft is inserted thereto, wherein a relative phase angle with respect to the camshaft is variable, an inside bracket configured to transmit rotation of the camshaft to the cam device, a lifter in which the inside bracket is rotatably inserted therein and on which a cylinder opening and a shaft opening are formed thereon, a control shaft parallel to the camshaft and to which a control rod, inserted into the shaft opening, is eccentrically formed, a control cylinder on which a control rod opening where the control rod is inserted therein is formed and inserted into the cylinder opening, a guide portion guiding movement of the lifter and a controller selectively rotating the control shaft, wherein the lifter may move.

A continuous variable valve timing apparatus may include a camshaft, a cam device on which a cam is formed respectively and of which the camshaft is inserted thereto, wherein a relative phase angle with respect to the camshaft is variable, an inside bracket configured to transmit rotation of the camshaft to the cam device, a lifter in which the inside bracket is rotatably inserted therein and on which a cylinder opening and a shaft opening are formed thereon, a control shaft parallel to the camshaft and to which a control rod, inserted into the shaft opening, is eccentrically formed, a control cylinder on which a control rod opening where the control rod is inserted therein is formed and inserted into the cylinder opening, a guide portion guiding movement of the lifter and a controller selectively rotating the control shaft, wherein the lifter may move.

A continuous variable valve duration apparatus includes a camshaft, a first and second cam portion, each including a cam and a cam key, where the camshaft is inserted into the first and second cam portions and where relative phase angles with respect to the camshaft are variable, a first and second inner bracket transmitting a rotation of the camshaft to the first and second cam portions respectively, a first and second slider housing, a cam cap rotatably supporting the first and second cam portions respectively, a slider pin rotatably inserted into the first sliding hole and slidably inserted into the camshaft, a cam pin on which a cam key slot for the cam key to be slidably inserted thereinto is formed, a control shaft disposed parallel to the camshaft and engaged with the first and second slider housings, and a control portion selectively rotating the control shaft.

A continuous variable valve duration apparatus may include a camshaft, a cam device, of which the camshaft is inserted thereto, of which a phase angle with respect to the camshaft is variable, and the cam device on which a cam key is formed, an inside bracket transmitting rotation of the camshaft to the cam device and on which a first slide opening and a second sliding opening are formed respectively, a slider housing in which the inside bracket is rotatably inserted and of which relative position with respect to the camshaft is variable, a controller selectively changing the relative position of the slider housing, a cam pin of which a cam key opening for the cam key to be slidably inserted thereto is formed and slidably inserted into the second sliding opening and a slider pin rotatably inserted into the first sliding opening and slidably inserted into the camshaft.

A continuous variable valve duration apparatus may include a camshaft, a cam device, of which the camshaft is inserted thereto, of which a phase angle with respect to the camshaft is variable, and the cam device on which a cam key is formed, an inside bracket transmitting rotation of the camshaft to the cam device and on which a first slide opening and a second sliding opening are formed respectively, a slider housing in which the inside bracket is rotatably inserted and of which relative position with respect to the camshaft is variable, a controller selectively changing the relative position of the slider housing, a cam pin of which a cam key opening for the cam key to be slidably inserted thereto is formed and slidably inserted into the second sliding opening and a slider pin rotatably inserted into the first sliding opening and slidably inserted into the camshaft.