Abstract: An inlet port for an internal combustion engine has an inlet port opened on an end face of a cylinder chamber at an off-center position, and the inlet hole is provided with an inlet valve and connected to an inlet passage. The inlet passage comprises a swirl generating section and an introducing section, and width between the peripheral surface of the valve stem of the inlet valve and the wall surface of the swirl generating section is made larger at the outside part on the wall side of the cylinder chamber than at the inside part on the center side of the cylinder chamber. The introducing section is connected to the outside part of the swirl generating section. In the plane intersecting perpendicularly to the center line of the introducing section within the parallel plane to the opening face of the inlet hole, the width of the outside part of the swirl generating section is set between 1.1 times and 2.8 times of the width of the inside part.

Abstract: A jet control type carburetor according to the present invention includes an intake pipe having an intake passage formed in an inner wall thereof, the intake passage allowing an intake air to flow therethrough; a venturi provided in the intake pipe, for controlling flow velocity and pressure of the intake air in the intake passage; a fuel nozzle opened into the intake passage and connected to a fuel supply source through a fuel passage for sucking the fuel within the intake passage from the fuel nozzle in order to introduce the mixture of air and fuel within the intake passage; a throttle valve provided downstream of the venturi, for controlling the flow rate of the mixture of intake air and fuel; a control fluid nozzle opened into the intake passage and connected to a fluid supply source through a control fluid passage for jetting the flow of the control fluid to the fuel spurted from the fuel nozzle to afford the kinetic energy of the control fluid to the fuel, and a throttle means provided upstream of the

Abstract: A flowmeter comprises a first tube having a first flow passage therethrough with its cross-sectional area being smaller at the outlet than at the inlet, a second tube disposed substantially concentrically within the first flow passage and having a second flow passage therethrough with its cross-sectional area being minimum substantially midway thereof, a third flow passage providing fluid communication between ports opening respectively at a sidewall of the second tube into the second flow passage adjacent to the minimum portion and at a sidewall of the first tube into the first flow passage, and a sensor disposed in either the third flow passage, the sidewall of the first tube, or the sidewall of the second tube for detecting periodic variations of a fluid flowing through the first, second, or third flow passage. The flowmeter detects the frequency of variations in the pressure or speed of a fluid, thus detecting the rate of flow of the fluid through the first and second tubes.

Abstract: A jet control type carburetor according to the present invention includes an intake pipe having an intake passage formed in an inner wall thereof, the intake passage allowing an intake air to flow therethrough; a venturi provided in the intake pipe, for controlling flow velocity and pressure of the intake air in the intake passage; a fuel nozzle opened into the intake passage and connected to a fuel supply source through a fuel passage for sucking the fuel within the intake passage from the fuel nozzle in order to introduce the mixture of air and fuel within the intake passage; a throttle valve provided downstream of the venturi, for controlling the flow rate of the mixture of intake air and fuel; a control air nozzle opened into the intake passage and connected to an air supply source through a control air passage for jetting the flow of the control air to the fuel spurted from the fuel nozzle to afford the kinetic energy of the control air to the fuel; and a throttle means provided upstream of the control a