Disclosed is a fluid accelerator provided on a fluid flow path so as to improve the fluid flow velocity. To this end, provided is a fluid accelerator comprising: a body formed in a cylindrical structure so as to be provided on a fluid flow path; a center hole forming a venturi passage in the vertical direction in the center of the body and having a helical guide groove provided on the inner circumferential surface of the venturi passage; and a plurality of middle holes formed in the vertical direction of the body along the edge of the center hole around the center hole. The fluid accelerator of the present invention can be easily provided in conventional device using fluid, thereby improving the fluid velocity.

An internal combustion engine includes: an engine body (10) having at least one cylinder; and an air-supply manifold (4) including an adjustment pipe (12). The length of the adjustment pipe is set so that a first pressure wave (14A) propagating from the air-supply manifold toward the adjustment pipe and a second pressure wave (14B) propagating from the adjustment pipe toward the air-supply manifold have opposite phases from each other at the cylinder.

A vehicle engine includes a cylinder block, a cylinder head installed at an upper portion of the cylinder block and forming a combustion chamber therein, a piston installed at the cylinder block and reciprocating in the cylinder block so that the volume of the combustion chamber is compressed or expanded, an injector installed at the cylinder head for injecting fuel into the combustion chamber, a spark plug installed at the cylinder head for igniting the fuel injected from the injector, and a voltage generating member installed inside the piston so that a voltage is generated by a pressure generated during a compression stroke of the piston.

In a method for operating a combustion engine in which exhaust gas located in a cylinder during an outlet cycle thereof is ejected from the cylinder and supplied to an exhaust system, a particularly high specific power output of the combustion engine and/or a particularly low specific fuel consumption are to be made possible, in a particularly simple and reliable manner. For this purpose, according to the invention, in a first cycle phase of the outlet cycle the pulse of the exhaust gas pressure wave flowing out of the cylinder is transmitted in whole or in part to the primary side of an exhaust gas charge pump, before the exhaust gas is passed to the exhaust system in a second cycle phase of the outlet cycle.

An intake system of an engine includes an engine and an intake manifold. The intake manifold defines individual intake air passageways each connecting one of cylinders to a volume chamber. Each of the individual intake passageways includes a first route and a second route. The first route has a natural frequency, of an air column, synchronized with a first revolution higher than an engine revolution for maximum torque such that a dynamic supercharging effect is obtained at the first revolution. The second route has a natural frequency, of an air column, synchronized with a second revolution higher than the engine revolution for maximum torque such that a dynamic supercharging effect is obtained at the second revolution. The second revolution differs from the first revolution. A difference between the first and second revolutions is set lower than or equal to 15% of a maximum engine revolution.

A volumetric expander for increasing the air intake between a throttle body and an intake manifold includes a throttle body neck, a manifold adapter, and a throttle body adapter. The manifold adapter and the throttle body adapter are positioned opposite each other along a intake tube of the throttle body neck, wherein a first air channel traversing along the intake tube is aligned with a first intake opening of both the manifold adapter and the throttle body adapter. Additionally, a second air channel is aligned with a second intake opening of both the manifold adapter and the throttle body adapter. A manifold gasket is positioned into the manifold adapter and creates an air tight seal between the manifold adapter and the intake manifold, while a throttle body gasket is positioned into the throttle body adapter and creates an air tight seal between the throttle body adapter and the throttle body.

An air intake duct of a motorcycle extends rearwardly from a front portion of a motorcycle body so as to pass laterally of the left side of a motorcycle frame structure, and incoming wind is supplied as an intake air through the air intake duct to a combustion engine. The air intake duct is divided in a widthwise direction of the motorcycle. An upper dividing face of the air intake duct is disposed inward of an intermediate position, in a motorcycle widthwise direction, of the air intake duct.

An air intake apparatus includes an air intake apparatus body including a surge tank, a valve body rotatably attached to the surge tank and configured to rotate between an open position and a closed position to open and close a fluid passage formed at a partition wall dividing an inside of the surge tank into two parts, the valve body being out of contact with the partition wall at the open position and being in contact with the partition wall at the closed position, the air intake apparatus body being formed by a first member to which the valve body is attached and a second member joined to each other, and the first member including a jig-receiving portion arranged in a vicinity of the fluid passage and configured to receive a jig holding the first member when the first member and the second member are being joined to each other.

A vehicle engine includes a cylinder block, a cylinder head installed at an upper portion of the cylinder block and forming a combustion chamber therein, a piston installed at the cylinder block and reciprocating in the cylinder block so that the volume of the combustion chamber is compressed or expanded, an injector installed at the cylinder head for injecting fuel into the combustion chamber, a spark plug installed at the cylinder head for igniting the fuel injected from the injector, and a voltage generating member installed inside the piston so that a voltage is generated by a pressure generated during a compression stroke of the piston.

A combustion engine of a motorcycle has an engine rotary shaft extending in a vehicle widthwise direction. Incoming wind taken in from a front of a steering handle that is positioned in front of the combustion engine, is introduced through an air intake duct to the combustion engine. The air intake duct extends from the front of the steering handle to a rearward of a cylinder block so as to pass above a radiator and pass laterally of one side of the cylinder block.