An internal combustion engine having an improved oil treatment system. The internal combustion engine may be a splash lubrication engine in which oil is flowed through an oil circulation circuit by a passive pump. In another aspect, a dipstick tube may be provided that includes a portion of the oil circulation circuit. In a further aspect, the internal combustion engine comprises one or more protuberances that automatically penetrate an oil treatment apparatus upon the oil treatment apparatus being mounted to the internal combustion engine, thereby fluidly coupling the oil treatment apparatus to the oil circulation circuit.

An internal combustion engine having an improved oil treatment system. The internal combustion engine may be a splash lubrication engine in which oil is flowed through an oil circulation circuit by a passive pump. In another aspect, a dipstick tube may be provided that includes a portion of the oil circulation circuit. In a further aspect, the internal combustion engine comprises one or more protuberances that automatically penetrate an oil treatment apparatus upon the oil treatment apparatus being mounted to the internal combustion engine, thereby fluidly coupling the oil treatment apparatus to the oil circulation circuit.

A sawmill includes a four-stroke internal combustion engine having an output shaft for driving a sawblade. The output shaft has a longitudinal axis. The engine is mounted on the sawmill for rotation between a first operative position with the longitudinal axis of the output shaft extending at a first angle, and a second operative position with the longitudinal axis of the output shaft extending at a second angle transversely to the first angle. The engine has fuel injection to facilitate operation in the first and second operative positions and a lubrication system incorporating a wet sump. An oil pick up for the lubrication system is configured to pick up oil from the wet sump at both the first and second operative positions.

A sawmill includes a four-stroke internal combustion engine having an output shaft for driving a sawblade. The output shaft has a longitudinal axis. The engine is mounted on the sawmill for rotation between a first operative position with the longitudinal axis of the output shaft extending at a first angle, and a second operative position with the longitudinal axis of the output shaft extending at a second angle transversely to the first angle. The engine has fuel injection to facilitate operation in the first and second operative positions and a lubrication system incorporating a wet sump. An oil pick up for the lubrication system is configured to pick up oil from the wet sump at both the first and second operative positions.

Internal combustion engines having multi-stage telescoping poppet valves in lieu of conventional poppet valves are disclosed. The engines may have pistons with a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The piston heads may include one or more depressions and may be domed to facilitate the movement of air/charge in the cylinder. The engines may also have non-circular, preferably rectangular, cross-section pistons and cylinders. The engines also may include a split crankshaft. The engines may use the pumping motion of the engine piston to supercharge the cylinder with air/charge. The engines also may operate in an inverted orientation in which the piston is closer to the local gravitationally dominant terrestrial body's center of gravity at top dead center position than at bottom dead center position.

Internal combustion engines having multi-stage telescoping poppet valves in lieu of conventional poppet valves are disclosed. The engines may have pistons with a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The piston heads may include one or more depressions and may be domed to facilitate the movement of air/charge in the cylinder. The engines may also have non-circular, preferably rectangular, cross-section pistons and cylinders. The engines also may include a split crankshaft. The engines may use the pumping motion of the engine piston to supercharge the cylinder with air/charge. The engines also may operate in an inverted orientation in which the piston is closer to the local gravitationally dominant terrestrial body's center of gravity at top dead center position than at bottom dead center position.

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.

An internal combustion engine having an internal space including a crankcase chamber includes an oil tank, a first passage communicating a lower part of the internal space with a gas phase part of the oil tank, a first check valve provided in the first passage to permit a flow from the internal space to the oil tank, a second passage communicating the gas phase part with the internal space, a second check valve provided in the second passage to permit a flow from the second passage to the internal space, a third passage communicating a liquid phase part of the oil tank with the second passage, a third check valve provided in the third passage to permit a flow from the oil tank to the second passage, and a flow regulator valve provided in the third passage for regulating a flow of lubricating oil flowing through the third passage.

An internal combustion engine having an internal space including a crankcase chamber includes an oil tank, a first passage communicating a lower part of the internal space with a gas phase part of the oil tank, a first check valve provided in the first passage to permit a flow from the internal space to the oil tank, a second passage communicating the gas phase part with the internal space, a second check valve provided in the second passage to permit a flow from the second passage to the internal space, a third passage communicating a liquid phase part of the oil tank with the second passage, a third check valve provided in the third passage to permit a flow from the oil tank to the second passage, and a flow regulator valve provided in the third passage for regulating a flow of lubricating oil flowing through the third passage.