Abstract: A hydraulic control system for an internal combustion engine, includes a driven mechanism driven by hydraulic pressure fed through a flowing passage change-over valve. The flowing passage change-over valve includes a valve body formed with a plurality of ports which are respectively communicated with the supply passage and the oil passage, and a spool valve body slidably disposed in the valve body to open and close the plurality of ports, the ports including a supplying port communicated with the supplying passage. The maximum cross-sectional area of the supplying port is larger than a minimum cross-sectional area of the supplying passage. The flowing passage change-over valve is supplied with electric current to heat hydraulic fluid kept in the flowing passage change-over valve so as to lower a viscosity of the hydraulic fluid.

Abstract: A hydraulic control system for an internal combustion engine, includes a driven mechanism driven by hydraulic pressure fed through a flowing passage change-over valve. The flowing passage change-over valve includes a valve body formed with a plurality of ports which are respectively communicated with the supply passage and the oil passage, and a spool valve body slidably disposed in the valve body to open and close the plurality of ports, the ports including a supplying port communicated with the supplying passage. The maximum cross-sectional area of the supplying port is larger than a minimum cross-sectional area of the supplying passage. The flowing passage change-over valve is supplied with electric current to heat hydraulic fluid kept in the flowing passage change-over valve so as to lower a viscosity of the hydraulic fluid.

Abstract: A valve timing control system for an internal combustion engine includes a housing having and a cover member mounted thereto, a phase adjusting mechanism accommodated in the housing to hydraulically change the rotation phase of a crankshaft and a camshaft, a supply/discharge rod arranged through a through hole of the cover member and connected to the phase adjusting mechanism, a seal ring engaged with the supply/discharge rod to hermetically seal a clearance between the supply/discharge rod and the phase adjusting mechanism, a taper surface formed on the periphery of the through hole to increase the diameter of the through hole toward the outside of the housing, and a protrusion formed with the cover member in a radially inside area thereof to protrude in the axial direction of the system, wherein the through hole is formed at the protrusion.

Abstract: A valve timing control system for an internal combustion engine includes a housing having and a cover member mounted thereto, a phase adjusting mechanism accommodated in the housing to hydraulically change the rotation phase of a crankshaft and a camshaft, a supply/discharge rod arranged through a through hole of the cover member and connected to the phase adjusting mechanism, a seal ring engaged with the supply/discharge rod to hermetically seal a clearance between the supply/discharge rod and the phase adjusting mechanism, a taper surface formed on the periphery of the through hole to increase the diameter of the through hole toward the outside of the housing, and a protrusion formed with the cover member in a radially inside area thereof to protrude in the axial direction of the system, wherein the through hole is formed at the protrusion.

Abstract: A vibration and noise free pump is disclosed. The pump includes a plurality of cylinders in radial arrangement about an axis. A piston is slidably supported in each of the cylinders. Each of the pistons has a vent opening in addition to a set of inlet openings to admit escape of liquid out of its piston inner chamber into a well with the piston in the compression stroke. With the provision of the vent opening, a surge pressure in each of the pistons has been reducedsed.