Hitachi, Ltd.

Hitachi Automotive Engineering Co., Ltd.

Yoshihito Sekine

Nobukatsu Arai

Toshifumi Usui

Hiroatsu Tokuda

Mitsukuni Tsutsui

Tadao Osawa

Atsushi Miyazaki

Chihiro Kobayashi

Tetsuo Matsukura

Shinya Igarashi

Haruhiko Maeda

An air flow meter comprises a main passage for an axial main air flow; an axial subpassage for air flow, disposed in the main passage and formed so that part of the air in the main passage is taken in at an upstream side thereof and flows in the same direction as the axial main air flow; a radial subpassage for air flow, intersecting the axial subpassage at a downstream side of the axial subpassage so that air from the axial subpassage flows into the radial subpassage and is divided into two radial air flows running in different radial directions; the air having passed through the radial subpassage joining the axial main air flow. An air flow sensing means is disposed in the radial subpassage for sensing a flow rate of air therein, and a projection is disposed in the radial subpassage around the intersection of the axial and radial subpassages, for suppressing turbulence of air flow around the intersection.

Air flow meter

A detecting module for an air flow meter for internal combustion engines has an arm provided with a heat wire sensor at one end thereof and with a signal processing unit at the other end, and is provided with a predetermined constant length. A body member assembled with the detecting module is selected from among several varieties of body members produced for engines with different stroke volumes, each of which has an main air path formed by an axial bore having a diameter commensurate with the stroke volume. A bridging member formed across the axial bore which forms the main air path is provided therein with a by-pass path for by-passing a part of the airflow within the main air path and a communicating hollow portion for accommodating the arm. The body member is further provided with a mount for fixing the detecting module, thereon, the height of which is different in each variety of the body members, so that the heat wire sensor is always placed in a predetermined metering area within the by-pass path, irrespective of the diameter of the axial bore forming the main air path, when the arm is accommodated in the hollow portion.

Air flow meter for internal combustion engines and a manufacturing

Flow rate measuring method and apparatus for determining a flow rate of a fluid flowing through a pipe by using a fuzzy inference system which is operative on the basis of fuzzy knowledge including fuzzy rules each described in the form of an IF part and a THEN part, and membership functions defining meanings of statements described in said IF and THEN parts. Flow velocity of the fluid is measured at a plurality of locations within the pipe by a plurality of sensors. A table of membership functions indicating grades of fitness of the flow velocities to a distorted flow model distribution is provided in a storage together with a mean flow rate calculating expression for deriving a flow rate corresponding to the distorted flow model distribution. A membership grade of the measured flow velocity to the distorted flow model distribution is determined by referring to the membership function table through the medium of the measured flow velocity, and a weighted mean of the flow rates given by the mean flow rate calculating expression is determined by using as a weight the membership grade to the distorted flow model distribution.

Method and system for measuring fluid flow rate by using fuzzy inference

Hot-wire air flow meter

The present invention whose object is to provide a hot wire type of flow meter capable of accurately detecting a flow rate under various conditions required for satisfying a desire for low fuel consumption of an engine system and space saving in an engine room, the present invention being characterized in a hot wire type of air flow meter including a main flow passage forming an air intake flow passage of an internal combustion engine, a hot wire element measuring intake air, and a bypass having the hot wire element therein and disposed in the main flow passage, the hot wire type of air flow meter comprising: a flow passage forming the bypass, and formed in the axial direction of the main flow passage; and a flow passage forming the bypass and formed in the radial direction of the main flow passage, the flow passage having a structure designed in such a manner that the upper stream portion of an outlet portion thereof projects over the lower stream portion of the same.

Hot wire type of air flow meter and internal combustion engine using the

A compact hot-wire type air flow meter for an internal combustion engine with a high measuring accuracy is provided with a primary flow path forming an intake air passage and an auxiliary flow path incorporating therein a hot-wire element for measuring the intake air. The auxiliary flow path is defined by a flow path in an axial direction of the primary flow path and a flow path in a radial direction of the primary flow path.

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Ibaraki, Japan

Yoshihito Sekine