Abstract: An electromagnetic apparatus for driving a valve such as an intake valve of an internal combustion engine drives the valve to its closing position without generating vibration and noises which are detrimental to durability and reliability of the valve. The valve speed is controlled either mechanically or electrically so that it is reduced to substantially zero when the valve sits on a valve seat. To mechanically control the valve speed, air or magnetic liquid is used as a cushion against the valve movement, or springs having a non-linear spring modulus such as a double-spring or a barrel spring are used to bias the valve movement. To electrically control the valve speed, an electrical signal representing the valve position is used to determine energization timing of the solenoids which drive the valve to an open or closing position. Such electrical signal is generated by an eddy current, resistance or spring load detector.

Abstract: A solenoid-operated hydraulic control valve is disclosed which may be employed in a fuel injection system for an internal combustion engine. The hydraulic control valve has a valve plunger which is drawn by a solenoid when turned on for selectively establishing and blocking fluid communication between an inlet and an outlet. A fluid chamber is formed to which fluid pressure is supplied from the inlet. The fluid pressure in the fluid chamber acts on the valve plunger in a direction opposite to that of the attracting force of the solenoid when turned on for compensating the attracting force produced by residual magnetism in the solenoid immediately after the solenoid is turned off.

Abstract: An accumulator fuel injection system for automotive vehicles is provided which includes an accumulating chamber storing therein fuel under a given pressure, a plurality of fuel injectors communicating with the accumulating chamber for injecting the fuel stored therein into engine cylinders of an engine, and a pressure regulator for regulating the pressure of fuel flowing through a drain passage from the accumulating chamber to a fuel tank. When a throttle valve is fully closed during a high-load engine operation, the fuel regulator opens the drain passage to decrease the pressure of fuel within the accumulating chamber to a target pressure level speedily. This allows an actual fuel injection pressure to follow a change in the target pressure level quickly according to an engine operating condition when the throttle valve is reopened.

Abstract: A fuel injection device includes an injection hole for injecting fuel therethrough, a needle movable between a first position to open the injection hole and a second position to close the injection hole, and a back-pressure chamber. The fuel injection device further includes a two-way solenoid valve for opening and closing a flow passage between the back-pressure chamber and a drain side so as to change a pressure in the back-pressure chamber. The needle is movable between the first and second positions depending on the pressure in the back-pressure chamber. A first flow restrictor and a second flow restrictor are provided in a flow passage, which introduces high-pressure fuel into the back-pressure chamber, so as to restrict a flow of the high-pressure fuel passing therethrough. The first and second flow restrictors may be arranged in series to each other.

Abstract: A common-rail fuel injection system for an engine includes a fuel injector having a nozzle hole. A common rail stores high-pressure fuel. The common rail is connected to the fuel injector to feed the high-pressure fuel thereto. A movable nozzle needle disposed in the fuel injector blocks and unblocks the nozzle hole in accordance with movement thereof. A back pressure control chamber defined in the fuel injector is connected to the common rail to receive the high-pressure fuel therefrom. The nozzle needle is urged in a direction of blocking the nozzle hole in response to a pressure in the back pressure control chamber. A fuel chamber defined in the fuel injector is connected to the common rail to receive the high-pressure fuel therefrom. The nozzle needle is urged in a direction of unblocking the nozzle hole in response to a pressure in the fuel chamber. A fuel-pressure-responsive 2-way valve controls the pressure in the back pressure control chamber.

Abstract: A fuel injector wherein a piston driven by the extension and contraction of a piezoelectric actuator changes the pressure of a working fluid in a variable pressure chamber and back pressure chamber so as to drive a needle valve to open and close a fuel injection hole, wherein undesirable secondary injection after a main injection in prevented by providing a throttle portion for narrowing the communicating passage between the variable pressure chamber and back pressure chamber when the piston moves forward and the needle valve closes the fuel injection hole.

Abstract: The present invention relates to a method of manufacturing a metal-impregnated body by immersing a porous ceramic or ceramic powder in a solution containing a chemical compound having an OH radical selected from the group consisting of water and aqueous solutions of methanol, ethanol, butanol, acetone, acetic acid and ammonium hydroxide; drying and molding it into a porous body; and then impregnating said porous body with a molten metal.