Hitachi, Ltd.

Other

Hitachi Automotive Systems, Ltd.

Hitachi Automotive Engineering Co., Ltd.

Hitachi Car Engineering Co., Ltd.

Chihiro Kobayashi

Shinya Igarashi

Nobukatsu Arai

Takayuki Saito

Hiroshi Hirayama

Takeshi Morino

Yuki Okamoto

Tsutomu Kono

Kaoru Uchiyama

Atsushi Miyazaki

Takayuki Yogo

Takehiko Kowatari

Atsushi Kanke

Yukio Kato

Mitsukuni Tsutsui

Yoshihito Sekine

Izumi Watanabe

Yasunori Mouri

Masayuki Kozawa

Masuo Akamatsu

Kenji Ohta

Hitoshi Ishikawa

Akira Takasago

Yasuji Nishi

Tadashi Isono

Takashi Kadohiro

Yasuo Makie

Tetsuo Matsukura

Haruhiko Maeda

Masatomo Ide

Kiichi Otaka

Yasunobu Kojima

Shinya c/o Hitachi Car Engineering Co Igarashi

A thermal type air flow meter, capable of suppressing deformation of a base member at the time of molding to secure dimensional accuracy and reduce an influence of a dimension change on measuring accuracy, is to be placed in an intake passage of an internal combustion engine. The thermal type of air flow meter includes a resin component having a secondary passage into which part of the air passing through the intake passage can flow, and a circuit board configured to output a signal according to an air flow rate based on a signal from a flow rate detecting element disposed on the circuit board. The circuit board on which the flow rate detecting element is disposed is installed so that the flow rate detecting element is placed in the secondary passage. The resin component includes a board fixing part to which the circuit board is fixed, a secondary passage constituting part that is a part of the secondary passage, and ribs provided on a rear surface, which is a side opposite to a surface of the board fixing part, with the ribs forming a grid pattern.

Thermal type air flow meter having a reinforcing structure provided on the base member between the board fixing part and the secondary passage constituting part

A thermal type air flow meter that is capable of suppressing deformation of a base member at the time of molding is disclosed, to thereby secure dimension accuracy and reduce an influence of a dimension change on measuring accuracy. The meter includes a housing member placed in an intake passage of an internal combustion engine, and a base member fixed to the housing member and includes a secondary air passage into which part of air passing through the intake passage flows. The base member is a plate-like resin molded component formed of a synthetic resin material and includes a reinforcing structure integrally formed between a board fixing part to which a circuit board is fixed; and a secondary passage constituting part formed at a leading end part of the board fixing part, the reinforcing structure enhancing strength of the base member.

Provided is a sensor structure capable of improving the reliability of connecting parts of electronic components and achieving excellent productivity and reduction in size and weight, for example, when electronic components are externally mounted on input/output terminals of a sensor. A relationship between a linear expansion coefficient for a housing serving as a base of a structure and a linear expansion coefficient of a resin material for a sensor casing of a sensor to be mounted is set to satisfy 'sensor casing&#x3c;linear expansion coefficient &#x3b1;&#x3c;housing'. When electronic components are externally mounted, the electric components are mounted on input/output terminals which are integrally formed on the side of a component having a small linear expansion coefficient, i.e., on the side of the sensor casing.

Sensor structure

The present invention utilizes self-heating of electronic components to improve a humidity sensing part with low environment resistance, such as a condensation problem and the like, and also to enhance the heat radiation efficiency of electronic components. The humidity sensing part is used in an intake tube of an automobile by integrating, for example, with a heating resister type mass air flow measurement device. A humidity sensing element is mounted on an electronic circuit board in a mass air flow measurement device with the temperature thereof starting to increase immediately after a sensor has been actuated. This urges the temperature of the humidity sensing element to start increasing (being heated) immediately after the sensor has been actuated. To urge the humidity sensing element to be further heated, a base plate is composed of two types of materials, resin and metal. A part of the base plate holding an area of the electronic circuit board generating a large quantity of heat is composed of the metal. A part of the base plate corresponding to the periphery of the humidity sensing part which is to be heated is composed of the resin.

In an intake air mass flow measurement device, for preventing clogging in a pressure intake tube due to water or the like entering the pressure intake tube in a device measuring a pressure in the intake air tube, the intake air mass flow measurement device includes a mass air flow measurement device for measuring an intake air mass flow in an intake air tube; and a pressure sensing device for sensing pressure in the intake air tube, the pressure sensing device being integrated with the mass air flow measurement device, and an aperture plane opened to the inside of a main air flow passage for detection of the pressure takes in pressure by using a gap generated between a main air flow passage constituting member and an insertion part of the mass air flow measurement device when a measurement part of the mass air flow measurement device is inserted into the main air flow passage. With this construction, it is possible to provide a structure in which water or the like can hardly clog the pressure intake port.

Intake air mass flow measurement device

In a thermal type flow rate measurement apparatus comprising a sub-passage having a detour passage and a hole just before a flow rate measuring part, for preventing its output value from falling onto a negative side when the flow rate is abruptly changed, a slit is formed downstream of a flow rate detecting element located after the detour passage. The slit hole may be arranged between the flow rate detecting element and the outlet port part, and may be opened between a wall surface side and a recess part. Thereby, it is possible to prevent the output value from falling in the negative side upon rise-up thereof.

Flow measurement apparatus

To realize a control apparatus for an internal combustion engine having a heating resistor type air flow rate measuring apparatus which can effectively remove salinity adhered to the heating resistor. Salt adheres not only to the heating portion of a heating resistor but also to lead members and supporting members. When a certain time period is passed after the current supply to the heating resistor is stopped, the salt adhered thereto absorbs moisture in the air by deliquescence, and becomes salt water near the heating resistor and the support members etc. Then, suction air flows through an auxiliary air passage by the cranking of the engine to disperse the salt water adhered not only to the support member parts but also to the heating resistor. Thus, even if the heating resistor is supplied with current after the dissipation, salt components do not remain on the heating resistor.

Heating resistor type fluid flow rate measuring apparatus and control apparatus for internal combustion engine having the measuring apparatus

A thermal type gas flow measuring instrument measures gas flow with high precision by accurately correcting changes in radiation heat characteristics of a heating resistor due to contamination. The instrument comprises a second heating resistorwhose resistance value, which changes if contaminated, is calculated by measuring the terminal voltage thereof by calculating meansand the calculated value is compared with a temperature detected by a temperature detecting elementBased on the result of comparison, the level of contamination of the second heating resistoris determined. The second heating resistorand the first heating resistorare disposed in similar environments such that their levels of contamination can be considered equal. Based on the level of contamination calculated from the result of comparison, a correction value is calculated and the output of the first heating resistoris corrected in accordance with the correction value.

Thermal type gas flow measuring instrument

To correct properly the error of the thermal resistor type air flow measuring apparatus caused by the pulsation in the intake pipe in detecting the air flow of the internal combustion engine, a thermal resistor is placed in a passage inside the auxiliary air passage into which the reverse flow hardly flows directly and the error caused by the reverse flow is prevented. The existence of the reverse flow is judged by the ratio of the amplitude to the mean value using the maximum value, the minimum value and the mean value of the forward air flow waveform, and the error caused by the increase of the forward air flow is corrected.

Thermal resistor type air flow measuring apparatus

An air flow rate measuring apparatus generates a flow rate signal with a nonlinear characteristic from a flow rate detecting unit provided with a heat generating resistor and converts that into a signal with a linear characteristic by a linearizing circuit. Then, the flow rate signal is smoothed by a filter circuit to obtain a signal in which the measurement error due to a flow rate ripple is suppressed. Thereafter, the flow rate signal is again formed into a signal with a nonlinear characteristic by a nonlinear-form converting circuit to suppress resolution lowering due to analog-to-digital conversion.

Air flow rate measuring apparatus

A heating resistor type air flow rate measuring apparatus is provided with a couple of heating resistors placed at the positions where those resistors may each interfere thermally with respect to an air flow, and a couple of driving circuits for driving those heating resistors. The air flow rate signal is obtained by calculating the difference between the output signals of a couple of heating resistors in terms of heat radiation rate effected by an air flow, and adding the difference value onto the output signal of one of the heating resistors.

Heating resistor type air flow rate measuring apparatus

In flow detection by a thermal-type flow measuring instrument, a flow rate valve with reduced measurement error due to temperature variation can be obtained even under environment where a fluid temperature and a circuit temperature are different. A measurement error due to temperature variation of the fluid of the thermal-type flow measuring instrument can be corrected on the basis of a temperature of the fluid by adjusting the measurement error to be constant ratio irrespective of the flow rate. On the other hand, a temperature characteristic of the circuit is adjusted to be substantially zero %.

Thermal type flow measuring instrument and temperature-error correcting apparatus thereof

A thermal type air flow measuring instrument is mounted to a main passage forming an intake air passage of an internal combustion engine and is provided. with an auxiliary passage which includes a heating resistor and a temperature sensing resistor therein and an electronic circuit which is electrically connected to the heating resistor and the temperature sensing resistor. The auxiliary passage is a passage including at least one bent portion composed of a first path substantially parallel to the main passage and a second path having a path different in flow direction from the first path. A member forming the auxiliary passage is fixed in a united form to only a case member for interiorly protecting the electronic circuit, and the case member is fixed to the outer wall surface of the intake air passage. The auxiliary passage structure capable of being handled as a single module united to the case member is effective to the mass production of an air flow control system and the reduction in cost thereof since the structure can be mounted to different kinds of internal combustion engines.

Thermal type air flow measuring instrument for internal combustion engine

A thermal type air flow measuring instrument is mounted to a main passage forming an intake air passage of an internal combustion engine and is provided with an auxiliary passage which includes a heating resistor and a temperature sensing resistor therein and an electronic circuit which is electrically connected to the heating resistor and the temperature sensing resistor. The auxiliary passage is a passage including at least one bent portion composed of a first path substantially parallel to the main passage and a second path having a path different in flow direction from the first path. A member forming the auxiliary passage is fixed in a united form to only a case member for interiorly protecting the electronic circuit, and the case member is fixed to the outer wall surface of the intake air passage. The auxiliary passage structure capable of being handled as a single module united to the case member is effective to the mass production of an air flow control system and the reduction in cost thereof since the structure can be mounted to different kinds of internal combustion engines.

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Naka, Japan

Chihiro Kobayashi