Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Denki K.k.

Mazda Motor Corporation

Masanori Inada

Hichiro Ohtani

Tomoya Yamakawa

Akira Demizu

Akihiro Nakagawa

Setsuhiro Shimomura

Naruki Suetake

Hideo Shiraishi

Toshiro Hara

Yoshinobu Kido

Sakae Kiguchi

Kenji Ushijima

In a misfire detecting device for an internal combustion engine, a crank angle detector detects the crank angle of the engine, a speed detector detects the speed of the engine from the crank angle thus detected, a load detector detects the load of the engine from the speed thus detected; and a misfire detector detects the misfire rate of the engine from the load thus detected, and outputs a misfire detection signal when the misfire rate thus detected exceeds a misfire rate determining value set according to a certain amount of load.

Misfire detecting device for internal combustion engine

A misfire detection device for an internal combustion engine determines the pulse width T.sub.1 and the low level interval T.sub.2 of a rotation signal Sc generated by a rotation signal sensor. The rising and falling edges of the pulses of the rotation signal Sc corresponds to predetermined reference angular positions of respective cylinders. The ratio T.sub.2 /T.sub.1 or T.sub.2 /(T.sub.1 +T.sub.2) is calculated and an occurrence of misfire is detected when the ratio exceeds a predetermined reference level.

Misfire detection device for an internal combustion engine

A thermal flow sensor comprising a bridge circuit positioned in a fluid and including a platinum wire as a thermal resistor, an air temperature sensor and a pair of resistors, and a temperature control circuit for controlling a current flowing through the platinum wire to keep the bridge circuit in a thermally balanced condition. A voltage V.sub.h depending on a flow rate and output from the bridge circuit is input to a non-inverting input terminal of an operational amplifier. A sum of the currents output from the first and second constant current circuits connected to the non-inverting and inverting input terminals of the operational amplifier is set to zero by a constant current control circuit when the output voltage V.sub.h is equal to or less than a predetermined value and gradually increases from zero with an increase in the output voltage V.sub.h when V.sub.h is higher than the predetermined value.

Thermal flow sensor for compensating gradient of flow rate

An apparatus for defecting occurrence of misfiring in an internal combustion engine with improved reliability. A change in an angular velocity of a crankshaft of the engine and a change in the output of an air/fuel ratio sensor are monitored. Only when both changes indicate occurrence of misfiring independently from each other, it is decided that misfiring in the cylinder has taken place. Reliability in misfiring detection is improved by using the results obtained through at least two mutually different types of misfiring detections.

Misfiring detecting apparatus for an internal combustion device

In a heat-sensitive flow sensor including a bridge circuit composed of a heat-sensitive resistor formed on a substrate provided within a fluid flow passage and a plurality of resistors and a control circuit for controlling current supplied to the heat-sensitive resistor to maintain the bridge circuit in a thermally balanced condition, a flow rate being detected from the thermal balance condition of the bridge circuit, current supply leads and a base portion of the substrate are buried in a heat insulating support member supported by a base. Preferably, lead terminals of the heat-sensitive resistor formed on the base portion are also buried in the heat insulating support member.

Heat-sensitive flow sensor

An apparatus for measuring an air flow intake of an internal combustion engine which comprises an air flow sensor for measuring the level of the air flow intake and an interface circuit for receiving an output signal from the sensor. The air flow sensor includes a current output circuit which outputs a current corresponding to the level of the air flow intake as the output signal of the sensor, and the interface circuit includes a current to voltage converter which converts the current from the sensor into a voltage signal and outputs it to an A/D converter included in a fuel injection unit.

Apparatus for measuring air flow intake of internal combustion engine

A thermal flow sensor has a heat-sensitive resistor which is disposed at a predetermined angle relative to the line of stream of a fluid, and which has its heat-sensitive portion disposed on the surface portion of a substrate which is positioned downstream in the direction in which the fluid flows. Since the heat-sensitive resistor is already disposed at a predetermined angle relative to the line of stream of the fluid, this permits only slight influence on, hence, variation in detection characteristic to be caused by deviation in the disposition angle. Since the heat-sensitive portion is disposed on a surface portion positioned downstream in the direction of fluid flow, this restrains dust contained in air from directly depositing on the heat-sensitive portion, hence, from causing variation in detection characteristic.

Terminal flow sensor

A thermal flow sensor has a housing through the inside of which a fluid is allowed to flow, and a supporting pipe passage disposed within and substantially in the center of the housing. A plurality of thermosensitive resistors are supported on the outer periphery of the supporting pipe passage and are disposed within substantially the same plane normal to the flow of the fluid. A fluid temperature sensor is provided within the supporting pipe passage. The flow rate can be detected correctly even when the flow rate of the fluid varies within that same plane, since the sensor is adapted to detect the average flow rate.

Thermal flow sensor

A thermal flow sensor has a housing through the inside of which a fluid is allowed to flow, and a supporting substrate disposed within and substantially in the center of the housing. A flat-plate shaped thermosensitive resistor and a fluid temperature sensor are provided on the supporting substrate. The thermosensitive resistor is disposed on the supporting substrate by being supported by a plurality of slender supporting members which support end portions of the resistor in such a manner as to provide narrow portions of a heat transferring path. The sensor detects flow rate with a good sensibility, while preventing any reduction in high levels of measuring sensibility and responsibility that are possessed by a small thermosensitive resistor.

A thermal flow sensor constructed by a temperature control circuit which includes a bridge circuit consisting of a thermoresistor arranged in a fluid passageway and a plurality of resistors, and a correction circuit for correcting the output of the control circuit in accordance with a gradient of a flow rate detecting characteristic is described. The correction circuit includes a subtracting circuit for subtracting a predetermined value from an output of the control circuit, a voltage dividing circuit for dividing an output of the subtracting circuit and an arithmetic operating circuit for performing either an addition or a substraction between outputs of the dividing circuit and the control circuit. The correction circuit may further include an amplifying circuit for amplifying the output of the dividing circuit and may change the arithmetic operating circuit to the circuit for adding the outputs of the arithmetic operating circuit and the control circuit and for subtracting the output of the subtracting circuit from the added voltage.

Flow sensor incorporating a thermoresistor

A hot wire type flow sensor having a cylindrical housing to be placed in a fluid passage, a plurality of hot wire supporters mounted on the inner surface of the housing, a hot wire stretched between the supporters, and a control circuit connected to the hot wire to output a signal in proportion to a flow rate of fluid. The inner surface of the housing at the upstream side of the hot wire is so formed that the flow of the fluid is concentrated at the central part of the hot wire.

Growing community of inventors

Hyogo, Japan

Masanori Inada