Patents by Inventor Mitsuru Koiwa

Mitsuru Koiwa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5181498
    Abstract: An ignition apparatus for an internal combustion engine is able to reduce generation of noise and energy loss due to wiring to a substantial extent. A capacitor 4 is connected at one end thereof to a DC power supply so as to be charged thereby, and at the other end thereof to an ignition coil 5. A switching element 9 is connected between the capacitor and a primary winding of the ignition coil to form part of a discharge path through which the capacitor discharges. The switching element is made conductive by means of an ignition or trigger signal which is generated by a signal generator in synchronism with the rotation of the engine, so that the charged capacitor discharges through the primary winding of the ignition coil. The capacitor, the ignition coil and the switching element are formed integrally with each other, housed in a single casing 13 and connected to each other without the use of a wire harness.
    Type: Grant
    Filed: November 19, 1991
    Date of Patent: January 26, 1993
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Mitsuru Koiwa, Shingo Morita
  • Patent number: 5172302
    Abstract: An ignition coil unit comprising within an electrically insulating casing (31) an ignition coil (A) and a packaged power switch circuit (E). The packaged power switch circuit (E), which comprises a plurality of electric and electronic components (F) hermetically sealed within a mold resin (G) to form a single compact unitary piece, is disposed within a power switch cavity (31d) of the casing (31). An aluminum heat dissipating plate (30) may be attached at its first end (30a) to said packaged power switch circuit (E) in a thermally conductive relationship and exposed at its second end (30b) to the exterior of said casing (31).
    Type: Grant
    Filed: September 24, 1991
    Date of Patent: December 15, 1992
    Assignee: Mitsubishi Denki K.K.
    Inventors: Masaaki Taruya, Mitsuru Koiwa, Nobuyuki Sawazaki
  • Patent number: 5163411
    Abstract: A capacitor discharging type ignition apparatus for an internal combustion engine is disclosed in which a secondary winding voltage rises quickly and has an extended spark generation time as well.
    Type: Grant
    Filed: May 16, 1991
    Date of Patent: November 17, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Mitsuru Koiwa, Shingo Morita
  • Patent number: 5146907
    Abstract: An ignition apparatus for an internal combustion engine includes a current limiter for limiting a current supplied from a power source to an ignition coil to a predetermined maximum value irrespective of temperature variations. A current sensing resistor is connected between the power transistor and ground for sensing the magnitude of a primary winding current. A first constant current supply is connected at one end thereof to the base of the power transistor and at the other end to one end of the current sensing resistor through a first transistor. A second constant current supply is connected at one end thereof to the base of the power transistor and at the other end to the other end of the current sensing resistor through a second transistor.
    Type: Grant
    Filed: October 10, 1991
    Date of Patent: September 15, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Nobuyuki Sawazaki, Masaaki Taruya, Mitsuru Koiwa
  • Patent number: 5144935
    Abstract: An ignition coil unit comprising an open-circuit magnetic iron core (6) having a longitudinal axis C, a primary coil (2) wound around the open-circuit magnetic core (6), a secondary coil (7) wound around the primary coil (2) and an outer magnetic iron core (10) disposed around the secondary coil (7). A power switching element (9a) for switching a primary current flowing through the primary coil (2) is disposed on the longitudinal axis of the open-circuit magnetic iron core (6) at its one end. A magnetic shield (20,21) is disposed between the open-circuit magnetic iron core (6) and the power switching element (9a) for protecting the latter against leakage magnetic fluxes from the open-circuit magnetic iron core (6). The magnetic shield may be a magnetic shunt plate (20) for leading the leakage flux into the outer magnetic iron core (10) or a magnetic shield case (21) surrounding the power switching element (9a).
    Type: Grant
    Filed: September 30, 1991
    Date of Patent: September 8, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masaaki Taruya, Mitsuru Koiwa
  • Patent number: 5133318
    Abstract: A governor apparatus for an internal combustion engine of a capacitor discharge type capable of effectively preventing after-burning due to excessive fuel supply and building abnormal combustion, etc., during the high-speed operation of the engine. To this end, ignition is intermittently performed or periodically stopped and performed when the number of revolutions per minute of the engine is greater than a predetermined value.
    Type: Grant
    Filed: May 16, 1991
    Date of Patent: July 28, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masahiro Yokotani, Mitsuru Koiwa
  • Patent number: 5131377
    Abstract: The power transistor unit 2A for controlling the current supply to the primary side of the ignition coil 3 includes a light emitting diode 10 coupled to the output of the control unit 1, and a phototransistor 11 optically coupled to the light emitting diode 10. The light emitting diode 10 and the phototransistor 11 together constitute a optoisolator. Thus, the ignition coil 3 is electrically isolated from the control unit 1, and hence a filter circuit for suppressing noise from the ignition coil 3 can be dispensed with.
    Type: Grant
    Filed: June 20, 1991
    Date of Patent: July 21, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masaaki Taruya, Mitsuru Koiwa
  • Patent number: 5113840
    Abstract: An igniter for an internal combustion engine is provided which is small in size, efficient and inexpensive to manufacture. The entire manufacturing process can be easily automated. The igniter includes a power transistor circuit for turning on and off the current supply to a primary winding of an ignition coil, a current detector for detecting a current supplied to the ignition coil primary winding, and a current limiter for controlling the current supplied to the ignition coil primary winding based on the current detected by the current detector. The current detector comprises a conductor in the form of a conductive wire separately formed from the current limiter and connected between ground and a junction between the power transistor circuit and the current limiter.
    Type: Grant
    Filed: May 30, 1991
    Date of Patent: May 19, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masaaki Taruya, Mitsuru Koiwa
  • Patent number: 5109827
    Abstract: An ignition apparatus for an internal combustion engine is provided which is simple in the circuit arrangement and highly reliable in operation. An electromagnetic pickup coil generates an ignition signal having a magnitude proportional to the number of revolutions per minute of the engine in synchrony with the rotation thereof for controlling an ignition coil. A waveform shaper in the form of a comparator shapes the ignition signal from the pickup coil into a signal containing a pulse having a rising edge and a falling edge. An integrator integrates the ignition signal from the pickup coil to provide a rpm voltage representative of the number of revolutions per minute of the engine. A signal level controller controls the voltage level of the ignition signal based on the rpm voltage generated by the integrator. A current absorber absorbs from the ignition signal a current in accordance with the voltage of a power supply which powers the ignition coil.
    Type: Grant
    Filed: April 8, 1991
    Date of Patent: May 5, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hisanori Nobe, Mitsuru Koiwa
  • Patent number: 5070853
    Abstract: An ignition device for an internal combustion engine comprises an ignition signal generator whose output signal has a magnitude corresponding to the engine rpms and is in synchronism therewith, a d.c. bias circuit 3 having a predetermined construction and component parameter values for superimposing a d.c. bias voltage on the ignition signal, a threshold setting circuit for determining a threshold level voltage, a comparator 2b having a first input terminal for receiving a signal obtained by superimposing the ignition signal and the d.c. bias voltage and a second input terminal for receiving the threshold level voltage to thereby generate an output having an inverse level in response to the magnitude of the input voltages inputted to the input terminals, and a switching circuit 4 for controlling a primary current to an ignition coil in response to the output of the comparison circuit.
    Type: Grant
    Filed: January 8, 1991
    Date of Patent: December 10, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Mitsuru Koiwa
  • Patent number: 5058559
    Abstract: An improved apparatus for igniting fuel for an internal combustion engine wherein a rotor for a signal generator, a signal pickup located opposite to said rotor and a controlling section for the signal pickup are accommodated in a housing for a distributor, the housing being made of electrically conductive material and earthed, and the controlling section includes a heat sink arranged in a heat-transmitting relationship relative to the housing and a hybrid IC placed on the housing in a frame for the controlling section, the frame being made of non-electrically conductive material. Signal lead wires extending from the signal pickup and the frame for the controlling section are firmly secured together to the housing for the distributor by the tightening screws, and one of the signal lead wires is earthed via a tightening screw and the housing for the distributor. Similarly, an earthing pattern on the hybrid IC is earthed via the terminal plate, a tightening screw and the housing for the distributor.
    Type: Grant
    Filed: June 5, 1990
    Date of Patent: October 22, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Mitsuru Koiwa
  • Patent number: 5035229
    Abstract: An engine ignition device comprises a circuit which generates a bias voltage corresponding to the engine rpm and superimposes it on an ignition signal so that the closing rate of the primary power feeding circuit for an ignition coil is controlled, a switching operation level setting circuit for generating a set voltage which changes with the engine rpm at startup or idling, and a comparison circuit having a first input receiving the ignition signal and superposed bias voltage and a second input receiving the set voltage, and generating an inverted output.
    Type: Grant
    Filed: June 5, 1990
    Date of Patent: July 30, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Mitsuru Koiwa
  • Patent number: 5014675
    Abstract: An ignition apparatus for an engine reduces the duty cycle of a power transistor circuit for controlling the primary winding current of an ignition coil over the entire operating range of the engine including low and high speeds. In one embodiment, a signal generator generates an alternating output signal which is fed through a resistor to a wave form shaper for comparison with a threshold voltage. As long as the signal generator output is higher than the threshold voltage, the wave form shaper generates an output pulse for controlling a conduction time of the power transistor circuit. When the engine is operating at low speeds, the pulse width of the wave form shaper output is reduced by partially absorbing the signal generator output by a current absorbing circuit which is disabled at high engine speeds.
    Type: Grant
    Filed: May 14, 1990
    Date of Patent: May 14, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Mitsuru Koiwa
  • Patent number: 4987870
    Abstract: An ignition device for an engine comprises a signal generator to generate a signal in synchronism with the rotation of an engine, a waveform shaping circuit to shape the waveform of an output signal produced from the signal generator, an ignition device to determine ignition timing on the basis of the output of the waveform shaping circuit and to cause ignition in the engine, an ignition-cut controlling circuit to cut the igniting operation of the ignition device when the engine operates at more than a predetermined revolution number, a tachometer signal output circuit to detect the revolution number of the engine on the basis of the output of the waveform shaping circuit, and a tachometer driving means to receive the output of the tachometer signal output circuit and to drive a tachometer so as to indicate an engine speed.
    Type: Grant
    Filed: October 5, 1989
    Date of Patent: January 29, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Mitsuru Koiwa, Toshiyuki Hino
  • Patent number: 4977883
    Abstract: An ignition apparatus for an engine limits the primary winding current of an ignition coil to a prescribed level. The conducting time of drive transistors which control the primary winding current is controlled on the basis of the voltage across a capacitor which is charged by a signal generator. At normal engine speeds, when the primary winding current reaches the prescribed level, current is bypassed around the capacitor by a bypass transistor. When the engine is cranking and the signal generator voltage is low, a switching transistor disables the bypass transistor, and the capacitor is not bypassed, thereby preventing misfiring.
    Type: Grant
    Filed: March 19, 1990
    Date of Patent: December 18, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Mitsuru Koiwa
  • Patent number: 4899715
    Abstract: An ignition device for an internal combustion engine includes a transistor circuit used to turn a primary current of an ignition coil on and off to produce a high voltage for spark ignition. A reference voltage generator produces a temperature compensated reference voltage. A primary current detecting circuit produces a voltage corresponding to a primary current of the ignition coil. A comparator compares the temperature compensated reference voltage with the voltage produced by the primary current detecting circuit. A control circuit responsive to an output of the comparator controls a base voltage of the transistor circuit to a predetermined constant value.
    Type: Grant
    Filed: September 26, 1988
    Date of Patent: February 13, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Mitsuru Koiwa, Kouichi Okamura
  • Patent number: 4628249
    Abstract: This disclosure dipicts a circuit for power supply comprising: a first constant-output-current circuit (16) for generating a constant-current-output in response to a non-inverted output current from a comparator (4) for comparing an input signal voltage with a reference voltage; and a second constant-output-current circuit (18) for flowing a superfluous current to a lower potential side in response to an inverted output current from the comparator (4), the second constant-output-current circuit (18) including a plurality of NPN type transistors.
    Type: Grant
    Filed: July 13, 1984
    Date of Patent: December 9, 1986
    Assignee: Rohn Company Limited
    Inventors: Yoshihiro Ikefuji, Mitsuru Koiwa