Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Denki K.k.

Other

Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Satoshi Komurasaki

Atsushi Ueda

Toshio Iwata

Fumito Uemura

Isao Watanabe

Tsuneo Yamane

Yoshinobu Morimoto

Youichi Kadota

Hideki Umemoto

Nobuaki Murakami

Osamu Ito

Takanori Fujimoto

Toshiro Hara

Kiyoshi Ookawa

Syohichi Katoh

Shoichi Kato

Masanori Yamano

An acceleration detector comprising a housing adapted to be rigidly secured to an object whose acceleration is to be detected and a transducer assembly disposed within the housing for detecting the acceleration of the housing. The transducer assembly comprises a disc-shaped diaphragm having a circular central region flexible in response to the acceleration of the housing. A disc-shaped piezoelectric element is attached to the central region of the diaphragm for generating a signal representative of the acceleration of the housing. Positioning means are disposed on the diaphragm and the piezoelectric element for positioning the piezoelectric element relative to the central region of the diaphragm. The positioning means may comprise a projection disposed on the diaphragm and engageable with the piezoelectric element. The projection may be disposed at the center of the diaphragm and the piezoelectric element may have a central hole engageable with the positioning projection. The projection may be disposed on the diaphragm and engageable with an outer peripheral edge of the piezoelectric element.

Acceleration detector

An acceleration detector comprising a housing adapted to be rigidly secured to an object of which acceleration is to be detected and a transducer assembly disposed within the housing for detecting the acceleration on the housing. The transducer assembly comprises a disc-shaped diaphragm having a circular central region flexible in response to the acceleration on the housing and a plurality of radial arms integrally extending at equal intervals from the central region and supported by the housing at outer ends. A disc-shaped piezoelectric element is attached to the central region of the diaphragm for sensing flexture of the central region and generating a signal representative of the acceleration on the housing. The central region has a diameter not smaller than that of the piezoelectric element. The radial arms may have a total circumferential width dimension effective to improve temperature vs. resonance frequency characteristics of the transducer assembly. The housing may comprise a base and a cover securely connected together, and a continuous ring-shaped member connected to outer ends of the radial arms is firmly clamped in an air-tight manner between the base and the cover.

Acceleration detector with radial arm diaphragm

A vibration sensor is provided in which the depth of a caulked portion of the sensor's case is increased so as to increase the capacity of a recess defined between this caulked portion and the cover. The volume of a potting agent filling the recess can thereby be increased to improve the airtightness of the caulked portion and the reliability of the vibration detector. A vibration plate having cutouts circumferentially spaced along an outer, peripheral portion may be used in the vibration detector if the volume of the space formed on a lower side of the vibration plate is limited to about a few to ten percent of that of the space formed on the opposite, terminal side. The expansion of air in the spaces caused by a thermal shock is therefore substantially equal to the expansion of air contained in the space on the terminal side alone, so that vibration sensor can maintain sufficient airtightness and can be improved in reliability.

Vibration sensor including a reduced capacity lower portion for

An acceleration detector comprising a substantially hollow cylindrical acceleration transducer assembly including a piezoelectric element, an inertial weight and an output terminal in a stacked relationship. The acceleration transducer assembly is mounted on a cylindrical threaded bushing of a housing and is secured by a stop nut thread-engaged on the bushing. The stop nut has a contact surface at which the stop nut contacts and supports the inertial weight of the transducer assembly for securing the transducer assembly to the bushing. The contact surface is small enough to enable to obtain a substantially constant output over an oscillation frequency range of the acceleration to be detected.

An ignition timing control apparatus for an internal combustion engine can precisely sense an abnormality or fault in a knock sensing system, and properly control the ignition timing so as to prevent any possible knocking even if there is an abnormality in the knock sensing system. The apparatus includes a first switch for controlling the power supply to an ignition coil, a signal generator for generating an ignition signal in synchrony with the rotation of the engine to open and close the swtich, a resonance type acceleration senor for sensing a vibrational acceleration of the engine and generating a corresponding output signal, a controller for controlling the first switch based on the output signal of the acceleration sensor so that the engine is properly ignited by the ignition coil, a capacitance load having one end connected through a second switch to the output side of the acceleration sensor and the other end thereof connected to ground, an abnormality sensor for sensing an abnormality in a knock sensing system including the acceleration sensor and the controller based on a change in the output of the acceleration sensor in response to the closure of the second switch, whereby the controller controls the first switch based on the output signal from the abnormality sensor in such a manner that it retards the ignition timing of the engine by a prescribed extend from a normal ignition timing at which ignition takes place when there is no output from the abnormality sensor.

Ignition timing control apparatus with a knock sensor for an internal

An acceleration detector comprising an acceleration transducer assembly disposed in a housing and including a piezoelectric element and an inertial weight. A relatively soft resilient filler material is applied around the acceleration transducer assembly for resiliently supporting the acceleration transducer assembly relative to the housing so that the inertial weight can move relative to the piezoelectric element when an acceleration is applied to the inertial weight. A relatively hard sealing material is applied on the resilient filler material for sealing and covering the relatively soft resilient filler material against the environment. The resilient filler material and the sealing material may be thermosetting resin.

A vibration detecting device which comprises a bush of metal having a cylindrical portion at its center; a casing of a resinous material which is formed by insertion-molding along with the bush so as to form a receiving portion at the outer side of the cylindrical portion; a piezoelectric element, a terminal and a weight placed along the outer periphery of the cylindrical portion of the bush in the receiving portion; a nut fastened to the cylindrical portion to secure the piezoelectric element, the terminal and the weight, and a filler for sealing the nut and the other elements received in the receiving portion, wherein one side of the receiving portion with respect to the vibration detecting direction is open.

Vibration detecting device

A knocking suppression apparatus for an internal combustion engine has a noise removal circuit which is disposed between an acceleration sensor, which senses engine knocking, and a phase shifter, which controls the ignition timing of the engine. The noise removal circuit includes a switch which can be opened and closed to prevent signals from being input to the phase shifter, and a window comparator. When the window comparator determines that the output of the acceleration sensor contains high-level noise signals, the noise removal circuit opens the switch for a prescribed period to prevent the high-level noise signals from being input to the phase shifter and influencing the ignition timing.

Knocking suppression apparatus for an internal combustion engine

A knock control apparatus of ignition timing control type according to the present invention comprises, as one aspect thereof, a knock control level increasing means for augmenting a knock phenomenon suppressing function, so that, when the knock interval is short, the output characteristic of the integrating means is increased to raise the control level for suppressing the knock generating element in each cylinder of the engine, and that the integrating means output characteristic is invalidated when the condition of the internal combustion engine reaches the normal operating state. The knock control apparatus comprises, as another aspect thereof, a reset pulse generation circuit for resetting the voltage from the above integrator to zero at the interval of more than a predetermined number of times the ignition cycle and in synchronism with the ignition signal.

Knock control apparatus for internal combustion engines

An acceleration detector of the present invention which may be secured by a single screw to an internal combustion engine comprises a housing and a piezoelectric acceleration transducer assembly mounted in the housing by a stop nut. The detector comprises a recess for being engaged by a projection of the engine for positioning and preventing an undesirable rotation of the housing upon turning of the stop nut. The acceleration detector may comprise a low-friction washer between the nut and the terminal of the transducer assembly for preventing an undesirable rotation of the terminal upon turning of the nut. Alternatively, one of the terminals of the acceleration transducer assembly is made sufficiently rigid to permit the use of a tool on it to firmly hold it. An electrically insulating stopper projection may be provided between the terminals to prevent an undesirable rotation of the terminals. In order to facilitate the precise assembly of the acceleration transducer assembly, projection tabs are provided on the terminal for engagement with the piezoelectric element. Also, the contact surface of the stop nut may contact substantially the entire surface of the weight.

A vibration detecting device attached to, for example, an internal combustion engine with a boss having a mounting surface for mounting the device which has the purpose of detecting knocking of the engine from the vibration thereof. The device has a housing containing a piezoelectric element and a weight which is adapted to impose inertial force on the piezoelectric element in response to vibrations from the engine whereby signals representing the vibrations are derived from the piezoelectric element. The housing has a effective contact surface which is smaller in area than the mounting surface, and the whole of which is in face contact with the mounting surface when mounted. The device is so arranged that the signals from the piezoelectric element represent the vibrations from the engine exactly as the are.

An acceleration detector comprising a housing defining a cavity therein and including a metallic bushing and a resinous outer case. An acceleration transducer assembly is disposed on the bushing in the cavity, and a resilient filler material is applied around the acceleration transducer assembly for resiliently sealing the acceleration transducer assembly from the exterior. The resilient filler material is sufficiently resilient to allow the movement of the inertial weight relative to the housing when an acceleration is applied to the inertial weight. The metallic bushing and the resinous outer case are integrally attached together by insert-molding so that they become an integral structure.

A vibration detecting device especially intended for detecting the knocking of an internal combustion engine. Various components inclusive of a piezoelectric element are mounted around a cylindrical portion of a bush with an insulating tube disposed therebetween. An insulating tube fills the space between the cylindrical portion and the components that are arranged to be aligned with the cylindrical portion. The outermost part of the tube serves as a reference surface in arranging the components to be mounted in alignment with the cylindrical portion during assembly, thereby allowing them to be mounted precisely in alignment with the cylindrical portion.

In an electronic ignition apparatus, there are provided an ignition signal generator, an ignition circuit, an ignition-noise masking signal generator, a switching transistor and an ignition coil. The ignition signal of the ignition signal generator is supplied to the ignition circuit to produce a first ignition pulse and a second ignition pulse which is electrically isolated from the first ignition pulse. The first ignition pulse is applied to the switching transistor so as to switch the collector voltage thereof, whereby high voltage ignition pulse is produced in the ignition coil. The second ignition pulse is applied to the ignition-noise masking signal generator to produce an ignition-noise masking signal. The ignition-noise masking signal is superimposed on the ignition signal so as to mask the ignition noise at least when the high voltage ignition pulse is produced in the ignition coil.

Electronic ignition apparatus including ignition-noise making signal

An output of a knocking discriminator is integrated by an integrator and the integrated value is reset by a resetting device in response to the operation in the ignition timing. The resetting operation of the resetting device is caused when both a cylinder pulse signal and an output signal from a micro-computer are inputted, and the resetting operation is cancelled when at least one of the signals disappears.

Growing community of inventors

Himeji, Japan

Satoshi Komurasaki