Hitachi Automotive Systems, Ltd.

Hitachi Astemo Ltd.

Takeo Hosokawa

Hiroaki Hoshika

Takahiro Miki

Takayuki Yogo

Yuki Isoya

Ryo Ando

Hiroshi Onuki

Shigenobu Komatsu

Hiroshi Nakano

Takayuki Saito

Naoki Saito

Daisuke Terada

Masayuki Hio

Takahiro Yamamoto

Yoshiyuki Akiyama

A flow-volume detecting apparatus including a flow-volume detecting unit which measures a flow volume of a measured fluid, a flow-volume state determining unit which determines a flow-volume state of the measured fluid based on an output from the flow-volume detecting unit. The flow-volume detecting apparatus further including a plurality of filters which process a flow-volume signal, and a filter selecting unit which selects a filter that processes the flow-volume signal, wherein the filter selecting unit selects the filter that processes the flow-volume signal according to the flow-volume state determined by the flow-volume state determining unit.

Flow-volume detecting apparatus utilizing filter selection

According to the conventional knowledge, a thermal humidity measurement device has problems in which the direction of air flow is limited to one direction is too hard to handle in securing the humidity responsiveness because there are limitations on the mounting direction of the thermal humidity measurement device and the state of air flow. An introduction guide protrudes from an air introduction surface to the outside of a measurement chamber, is parallel to a humidity introduction port surface, and has a portion not in contact with an inlet surface of a humidity introduction tube as seen from any direction to guide the flow of air to the humidity introduction tube from any direction of 360&#xb0;.

Humidity measurement device

A thermal humidity measuring device includes first and second heating elements, and is capable of obtaining a plurality of measurement values (measured values) by effectively utilizing each of the heating elements, which includes measuring humidity by the first heating element. A thermal humidity measuring device includes a first bridge circuit that includes a first heating element that senses humidity, and a second bridge circuit that includes a second heating element that heats air around the first heating element. In the thermal humidity measuring device, a first output signal is extracted from the first bridge circuit, and the humidity is sensed. A second output signal is extracted from the second bridge circuit, and the second output signal includes information relating to at least any one of pressure, an air flow rate, and air temperature.

Thermal humidity measuring device

The purpose of the present invention is to reduce a load of preventing dew condensation, and to provide a highly reliable humidity detection device. In order to achieve the purpose, this humidity detection device is provided with: a humidity sensor having a humidity detection unit and a temperature detection unit; a heating resistor that heats the humidity sensor; and a heating control unit that controls a heating temperature of the heating resistor. The humidity detection device is characterized in having a target temperature storage unit that stores target temperatures of the heating resistor, said target temperatures having been determined corresponding to temperatures and humidities.

Humidity detection device

In order to provide a temperature and humidity sensor with improved reliability, the temperature and humidity sensor in which all or part of a case of the temperature and humidity sensor is inserted into a main duct for causing gas to pass through and which detects humidity of the gas, includes: a first sub-passage configured as a part of the case, a part of the gas passing through the main duct flowing in substantially the same direction as a flow in the main duct; a throttle section provided between an inlet and an outlet of the first sub-passage and on an inner surface of the first sub-passage, the throttle section having a throttle whose cross-sectional area is smaller than an average cross-sectional area of the entire first sub-passage; and a second sub-passage which connects an upstream side and a downstream side of the throttle section and is different from the first sub-passage. The first sub-passage and an inlet and an outlet of the second sub-passage are connected via respective connection ports, and the connection port between the inlet of the second sub-passage and the first sub-passage or the connection port between the outlet of the second sub-passage and the first sub-passage is provided on a side where a throttle is not provided when viewed from an axis in an upstream and downstream direction of the flow in the first sub-passage.

Temperature and humidity sensor

The purpose of the present invention is to enhance the detection accuracy of an absolute humidity determined from at least temperature and relative humidity when carrying out temperature control using a heating element according to detection characteristics for temperature and relative humidity. A physical quantity detection device according to the present invention is provided with a humidity sensor for detecting relative humidity and temperature, a heater for heating the humidity sensor, and a microcomputer and controls the heat generation amount of the heater by using the heater for heating and stopping heating such that an environment under measurement is at least a room temperature and is a temperature at which a relative humidity detection characteristic and temperature detection characteristic for the humidity sensor improve, thereby enhancing the accuracy of absolute humidity detection.

Physical quantity detection device

The purpose is to enhance the measurement stability of a flow rate detection unit in a physical quantity detection device by branching an auxiliary passage in which the flow rate detection unit is disposed into first to third passages and providing the third flow passage at an upstream part of the second flow passage. A physical quantity detection device has a circuit board provided with at least one detection unit for detecting the physical quantity of a gas flowing through a main passage and a circuit unit for computational processing of the physical quantity detected by the detection unit, a housing for accommodating the circuit board, a cover fixed to the housing, and an auxiliary passage formed by both the housing and cover that is configured to branch passages from a first passage to a third passage.

The present invention reduces, by optimizing disposition of components on an electronic circuit board, heat transfer from other components mounted on the same board, and improves measurement accuracy of an intake air temperature detection element. A physical quantity detection device of the present invention has an electronic circuit board, which is provided with one or more intake air temperature detection elements (elements having intake air temperature detection function), and which processes electric signals. Furthermore, the physical quantity detection device has a configuration wherein the intake air temperature detection elements, and a power supply regulator having the maximum heat generation quantity are mounted on the same electronic circuit board. The physical quantity detection device is characterized in that the intake air temperature detection elements are disposed on the air flow upstream side of the power supply regulator.

Intake temperature detection device and maximum heat generating amount components mounted on a single circuit board

In order to provide a highly precise and highly responsive humidity detection means with which diagnosis is easy, this control device for an internal combustion engine is characterized in that two or more sensors for detecting the humidity of the atmosphere or a gas mixed with the atmosphere are provided in the middle of the flow in an intake air passage of the internal combustion engine, at least one of these sensors being a relative humidity sensor for detecting the relative humidity, at least one other of the sensors being an absolute humidity sensor for detecting the absolute humidity, and the relative humidity sensor being arranged upstream from the absolute humidity sensor.

Control device for internal combustion engine

To achieve a physical quantity detection device capable of obtaining a desired overall device accuracy without unnecessarily raising the tolerances of detection elements, the present invention is characterized by having a plurality of physical quantity detection units for respectively detecting plurality of physical quantities, a storage unit for storing the error characteristics of individual physical quantity detection units, a physical quantity calculation unit for using at least two physical quantities detected by at least two of the plurality of physical quantity detection units to calculate a separate physical quantity, and an error calculation unit for reading the error characteristics of the plurality of physical quantity detection units from the storage unit and calculating the error of the separate physical quantity.

A humidity measuring device includes an apparatus that determines whether or not a water droplet adheres to a surface of a sensor element which detects the humidity, based on changes in humidity and temperature of the intake air. The apparatus calculates a determination value based on a rate of change of the temperature and a rate of change of relative humidity. The apparatus also compares the determination value with a threshold. The apparatus also determines that a water droplet adheres to the surface of the sensor element when a state where the determination value is larger than the threshold continues for a determination time or longer.

Intake air humidity measurement device for an internal combustion engine

A thermal-type flow meter for representing a flow rate of air by the frequency of a periodic signal, wherein abnormalities in the waveform of an output signal due to frequency variation is prevented while high-frequency noise is suppressed. The thermal-type flow meter pertaining to the present invention is provided with a plurality of switching elements connected in parallel, and varies a delay width between the switching elements in accordance with variation of the frequency of a periodic signal for representing a flow rate.

Thermal type flow meter

In order to make a physical quantity detection device whose sensor and logical circuit operate with different operating voltages have a simple configuration and be capable of recognizing a detection result of the sensor accurately, the physical quantity detection device according to the present invention is configured so that the sensor and the logical circuit may be connected by a bidirectional communication line and may be operate with mutually different operating voltages, and when receiving the detection result of the sensor, recognizes Hi/Lo level signals using second Hi/Lo level thresholds set up on arithmetic processing in place of first Hi/Lo level thresholds that an arithmetic unit has.

Radiated noises of an output pulse signal are reduced. A pulse signal outputting apparatus outputs a pulse signal generated by a modulating means outside, the modulating means includes a calculation circuit that has a pull-up resistor which is connected to power supply inside, a general-purpose input/output terminal that is connected to the calculation circuit, input/output selecting means for selecting whether the general-purpose input/output terminal is used as an input terminal or an output terminal, pull-up resistor connecting means for connecting or disconnecting the pull-up resistor and the general-purpose input/output terminal, and a pull-up resistor connection control circuit that performs control so that the pull-up resistor connecting means is operated when the general-purpose input/output terminal is selected as the input terminal, the general-purpose input/output terminal is selected as the input terminal by the input/output selecting means when a transition of an output signal level of the pulse signal starts, the pull-up resistor and the general-purpose input/output terminal are connected by the pull-up resistor connecting means when the general-purpose input/output terminal is selected as the input terminal, and the general-purpose input/output terminal is switched to the output terminal by the input/output selecting means after a certain period of time has passed.

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Hitachinaka, Japan

Takeo Hosokawa