Hitachi Automotive Systems, Ltd.

Hitachi Astemo Ltd.

Yuki Isoya

Hiroaki Hoshika

Takahiro Miki

Takayuki Yogo

Takeo Hosokawa

Takahiro Yamamoto

Tsutomu Kono

It is possible to reduce a degradation in accuracy after switching of a heating state or after change of the flow rate. A physical quantity detection device includes a flow rate measuring element which is equipped with a heating element and measures a flow rate of a measurement target fluid; a heating element control unit which switches a control state of the heating element to one of a heat generation state or a heat generation suppression state; and a signal processing unit which includes a buffer and a frequency analysis block, and processes a measured value of the flow rate measuring element, using a main frequency calculated by the frequency analysis block, in which the measured value for a past predetermined period is recorded in the buffer, the frequency analysis block calculates the main frequency by performing a frequency analysis of the measured value recorded in the buffer, when an occurrence of an event is detected, the signal processing unit performs a calculation, using the main frequency calculated immediately before for a predetermined period from the occurrence of the event, and the event is a sudden change in the measured value and switching of the control state performed by the heating element control unit.

Physical quantity detection device

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

Provided is a physical quantity measurement device capable of reducing a frequency analysis error of a gas flow rate as compared with the related art. A physical quantity measurement deviceincludes a flow rate sensorand a signal processing unit. The signal processing unithas a buffer, an offset adjustment unit, a gain calculation unit, a correction calculation unit, and a frequency analysis unit. The bufferstores a flow rate data based on an output signal of the flow rate sensorfor a predetermined period. The offset adjustment unitadjusts the zero point of the flow rate waveform. The gain calculation unitcalculates a correction gain of the flow rate waveform whose zero point has been adjusted. The correction calculation unitperforms the correction by multiplying the flow rate waveform whose zero point has been adjusted by the correction gain. The frequency analysis unitperforms a frequency analysis calculation of the corrected flow rate waveform and stores the data obtained by the calculation in the buffer. The gain calculation unitcalculates the correction gain at which the overflow does not occur in the frequency analysis unit

Physical quantity measurement device

It is possible to suppress overcorrection. A physical quantity detecting device includes: a physical quantity detecting sensor that detects a physical quantity of a measurement target fluid and outputs a detection signal; a compensation amount calculation unit that calculates, by using the detection signal, a lead compensation amount used in lead compensation for the detection signal; and a gain control unit that adjusts the lead compensation amount based on a deviation that is an amount of change in lead compensation amount over time.

Physical quantity detecting device

A decrease in the accuracy after switching of the heating state can be reduced. The physical quantity detecting device includes: a flow rate detecting unit configured to include a heating element to measure a flow rate of a fluid to be measured; a heating element control unit configured to switch a control state of the heating element to any one of a heating state and a heating suppression state; and a signal processing unit configured to process a measured value of the flow rate detecting unit. When the heating element control unit switches the control state, the signal processing unit processes an estimated value determined based on a measured value of the flow rate detecting unit before the switching for a predetermined period immediately after the switching.

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

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.

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

The present invention obtains a humidity measuring device capable of performing self-diagnosis with high reliability. This humidity measuring devicehas a diagnosis processing unitfor performing self-diagnosis by using gas temperatures and gas humidities before and after a gas in an ambient atmosphere to be measured is heat-controlled. The diagnosis processing unit has a diagnosis start determining unitfor determining whether the self-diagnosis can be started on the basis of an exchange state in the ambient atmosphere to be measured and the gas temperature and the gas humidity before the gas in the ambient atmosphere to be measured is heat-controlled, and a diagnosis continuation determining unitfor determining whether the self-diagnosis can be continued on the basis of the gas temperature and the gas humidity that are heat-controlled during the self-diagnosis.

Humidity measuring device

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 physical quantity measuring device includes a chip package and a casing. The casing fixedly stores the chip package. The casing includes a first bypass passage allowing a gas to be measured taken from a main passage, to flow in a first measuring unit, and a second bypass passage allowing the gas to be measured taken from the main passage, to flow in a second measuring unit. The chip package is configured to dispose a signal processing unit between the first and second measuring units. The casing has a cooling unit that allows the gas to be measured from the main passage to flow between the first measuring unit and the second measuring unit, and cooling the signal processing unit.

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Hitachinaka, Japan

Yuki Isoya