Hitachi, Ltd.

Hitachi Automotive Engineering Co., Ltd.

Other

Hitachi Car Engineering Co., Ltd.

Hitachi Automotive Systems, Ltd.

Hitachi, Ltd. and Hitachi Car Engineering Co., Ltd.

Takayuki Itsuji

Hiroshi Hirayama

Shinya Igarashi

Sadayasu Ueno

Kaoru Uchiyama

Norio Ichikawa

Yasuo Makie

Kunio Kondo

Masayuki Miki

Mitsukuni Tsutsui

Masuo Akamatsu

Hiroshi Yoneda

Hideki Mukuno

Jun Matsui

Masamichi Nawa

Masao Akamatsu

A power conversion apparatus includes a power conversion element; a capacitor; a control circuit that outputs a control signal to control operation of the power conversion element at the time of driving a load; a discharge control unit that outputs a discharge control signal to control operation of the power conversion element at the time of discharging the capacitor; a power supply circuit that generates a power supply voltage, on the basis of a voltage between both ends of the capacitor; and a driver unit that outputs a driving signal to operate the power conversion element, on the basis of the control signal or the discharge control signal. The power conversion element is operated according to the discharge control signal, a current is flown from the capacitor to the load through the power conversion element, and the capacitor is discharged.

Power conversion apparatus

An air flow sensor for an internal combustion engine is disclosed. An air flow rate measurement meter, a pressure gauge, electronically controlled throttle body, and the microcomputer, etc. are integrated as one body, and the correction of the air flow rate, the control, and the fault diagnosis, etc. are done in the integrated microcomputer. The air flow sensor outputs an air flow rate signal in which the error is deleted to suppress the discharge of the harmful exhaust gas from the internal combustion engine, carries out the self-diagnosis of the breakdown of the air flow sensor or the electronically controlled throttle body to prevent the accident beforehand, and controls to obtain the best intake air amount.

Air flow measuring device formed integrally with electronically controlled throttle body

A mask has a plurality of holes formed at positions corresponding to positions of a plurality of electrode portions on one surface of an object to be processed to mount thereon conductive particles , and the plurality of holes are opposite to the plurality of electrode portions formed on the object to be processed. A table has a plurality of holes for sucking the object to be processed from the other surface of the object to be processed , and for sucking the particles through the plurality of holes in the mask so that the particles may be mounted on the electrode portions formed on the object to be processed . A hopper contains therein the plurality of conductive particles , prevents the plurality of conductive particles from adhering to each other, and has a slit portion for dropping the plurality of conductive particles by the self-weight. A slit portion in the hopper is moved, facing the upper surface of the mask with a gap between the slit portion and the upper surface of the mask larger than a diameter of the particle , and the hopper is arranged in the front side in the moving direction, and the unit is arranged in the rear side, and the particles not dropped into the holes of the mask being collected by the collecting unit

Bump forming method and bump forming apparatus

An improved heating resistor type air flow measurement apparatus which can operate properly even when the noises are produced by a large surge current, and even when the air flow measurement apparatus is made of plastic member. The apparatus has a heating resistor arranged in the main air passage, a temperature-sensitive resistor and a flow measurement circuit for processing signals from their resistors. Inductors are provided between these resistors to prevent noise invasion into the flow measurement circuit.

Air flow measurement apparatus

A heating resistor type air flow meter for measuring the amount of air flow which passes through an intake pipe for an internal combustion engine. The air flow meter has a constant-temperature control circuit for detecting air flow, which has a bridge circuit including a heating resistor and a temperature-sensitive resistor each provided in the intake pipe, and a power amplifier circuit for amplifying a signal from the constant-temperature control circuit to generate an air flow signal. The power amplifier circuit has a plurality of amplification resistors which determine a mu-factor for the amplifier to correct the amount of air flow with respect to variation of temperature. At least an amplification resistor has a temperature coefficient different form that of the other amplification resistor, to compensate variation of the mu-factor of the power amplifier circuit.

Air flow meter of a heating resistor type

A hot wire type air flowmeter has a drive circuit for controlling the temperature of a hot wire type resistor and for outputting indications of controlling states as electric signals, an output adjusting circuit for adjusting the electric signals output from the drive circuit, and a subtracter provided in the output adjusting circuit of the hot wire type air flowmeter. The electric signals output from a non-inverting amplifier in the drive circuit are input to one input terminal of the subtracter and a standard voltage supplied via a voltage follower are input to the other input terminal of the subtracter.

Hot wire type air flowmeter

A flow rate of air flowing through an air inlet pipe is detected by a heating resistor disposed therein and converted into an electric signal. A digital processing unit carries out calculation to judge whether or not the converted signal coincides with a predetermined temperature value and to correct the converted signal so that the same is caused to coincide with the predetermined value if both the values do not coincide with each other. The corrected signal is used to keep the heating resistor at the predetermined temperature. The digital processing unit is integrated with the air inlet pipe independently of a digital processing unit for engine control.

Heating resistor type air flow meter with separate/processing unit

An air-fuel ratio control apparatus for an internal combustion engine includes a solid electrolyte having a first electrode disposed on one surface thereof to contact with the atmosphere and a second electrode disposed on the other surface thereof to contact with the exhaust gas from the engine through a diffusing resistor, and means for applying a voltage across the first and second electrodes to detect an oxygen pump current flowing in the solid electrolyte whereby a correction factor relating to a change in the diffusion coefficient of the diffusing resistor is computed so that the oxygen pump current detected by the detecting means is corrected in accordance with the correction factor and the air-fuel ratio of the exhaust gas is determined in accordance with the corrected oxygen pump current, thereby controlling the quantity of fuel supplied to the engine in accordance with the determined air-fuel ratio.

Air-fuel ratio control apparatus for internal combustion engines

A detecting element (6) comprising a solid zirconia electrolyte (6a), a reference electrode (6d), a detecting electrode (6c) and a diffusion member (6a) is provided, and also a driving circuit (1b, 4) for impressing a voltage between the electrodes (6c, 6d) of said detecting element so as to detect the threshold current of an oxygen ion pumping current (I.sub.p) is provided. The output of this driving circuit is delivered as a continuous output (V.sub.o) of an air fuel ratio of fuel gas comprising al the regions of rich, stoichiometric and lean air fuel ratios. On the other hand, an I.sub.p detection resistor (Rs) for detecting the pumping current flowing between the input/output terminals of the driving circuit is provided. The opposite-end voltages (V.sub.a, V.sub.o) of this I.sub.p detection resistor are compared by a comparator (5), and a step signal corresponding to the stiochiometric air fuel ratio (.lambda.) is outputted from this comparator.

Air fuel ratio measuring system

An air-fuel ratio control apparatus is disclosed in which an air-fuel ratio sensor disposed in the exhaust system of an internal combustion engine produces a voltage signal correlated with the excess air ratio of the ambient gas surrounding it and has such an output characteristic as to produce a maximum output only when the ambient gas is filled with air, the air-fuel ratio of the internal combustion engine being controlled to a proper value on the basis of the detection signal of the air-fuel ratio sensor. The air-fuel ratio control apparatus further comprises a sampling device for sampling the maximum output (V.sub.x) when it is decided that the output of the air-fuel ratio sensor is maintained for a predetermined length of time or longer at a predetermined value or higher, a memory for storing the sample value of the maximum output (V.sub.x) produced by the sampling device and updating the preceding sample value (V.sub.x-1) to the present sample value (V.sub.x) when a new maximum output is sampled each time of the decision, and a calibrator for calibrating the output characteristic of the air-fuel ratio sensor on the basis of the latest updated sample value (V.sub.x).

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Hitachinaka, Japan

Takayuki Itsuji