Patents by Inventor Shotaro Naito

Shotaro Naito 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: 6766874
    Abstract: A system for driving a hybrid vehicle comprising an engine; a motor/generator coupled to the engine; a battery connected to the motor/generator through an electric power converter; and a controller for controlling the engine and the motor/generator corresponding to driving condition of the vehicle, wherein the controller has a plurality of operating modes for controlling the engine and the motor/generator corresponding to an accelerator opening degree for operating the engine and a charge ratio of the battery, and the controller selects an engine running electric generating mode that the engine is operated as a driving source of the vehicle and the motor/generator and electric power generated by the motor/generator is recovered to the battery when the charge ratio is low; an acceleration mode that the engine and the motor/generator are operated as the driving source of the vehicle when the charge ratio of the battery is high, and the accelerator opening degree or a rate of change of the accelerator opening de
    Type: Grant
    Filed: September 29, 1999
    Date of Patent: July 27, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Shotaro Naito, Hiroshi Katada
  • Patent number: 6752226
    Abstract: A system for driving a hybrid vehicle having an engine, a motor/generator, a battery and a controller for the engine and the motor/generator. The controller has a plurality of operating modes. In an engine running electric generating mode, the engine is operated as a driving source of the vehicle and the motor/generator and electric power generated by the motor/generator is recovered to the battery when the charge ratio is low. In an acceleration mode, the engine and the motor/generator are operated as the driving source of the vehicle when the charge ratio of the battery is high, and the accelerator opening degree or a rate of change of the accelerator opening degree is large. In an engine running mode only the engine is operate as the driving source of the vehicle when the charge ratio of the battery is high and the accelerator opening degree is small.
    Type: Grant
    Filed: April 2, 2003
    Date of Patent: June 22, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Shotaro Naito, Hiroshi Katada
  • Publication number: 20030183430
    Abstract: A system for driving a hybrid vehicle comprising an engine; a motor/generator coupled to the engine; a battery connected to the motor/generator through an electric power converter; and a controller for controlling the engine and the motor/generator corresponding to driving condition of the vehicle, wherein the controller has a plurality of operating modes for controlling the engine and the motor/generator corresponding to an accelerator opening degree for operating the engine and a charge ratio of the battery, and the controller selects an engine running electric generating mode that the engine is operated as a driving source of the vehicle and the motor/generator and electric power generated by the motor/generator is recovered to the battery when the charge ratio is low; an acceleration mode that the engine and the motor/generator are operated as the driving source of the vehicle when the charge ratio of the battery is high, and the accelerator opening degree or a rate of change of the accelerator opening de
    Type: Application
    Filed: April 2, 2003
    Publication date: October 2, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Shotaro Naito, Hiroshi Katada
  • Publication number: 20020007975
    Abstract: A system for driving a hybrid vehicle comprising an engine; a motor/generator coupled to the engine; a battery connected to the motor/generator through an electric power converter; and a controller for controlling the engine and the motor/generator corresponding to driving condition of the vehicle, wherein the controller has a plurality of operating modes for controlling the engine and the motor/generator corresponding to an accelerator opening degree for operating the engine and a charge ratio of the battery, and the controller selects an engine running electric generating mode that the engine is operated as a driving source of the vehicle and the motor/generator and electric power generated by the motor/generator is recovered to the battery when the charge ratio is low; an acceleration mode that the engine and the motor/generator are operated as the driving source of the vehicle when the charge ratio of the battery is high, and the accelerator opening degree or a rate of change of the accelerator opening de
    Type: Application
    Filed: September 29, 1999
    Publication date: January 24, 2002
    Inventors: SHOTARO NAITO, HIROSHI KATADA
  • Patent number: 6236172
    Abstract: A method and apparatus for driving an electric vehicle having a synchronous traction motor. A peak value of induced electromotive force of the synchronous motor at a maximum allowable rotating speed is set to a value which is lower than an allowable voltage of the smoothing capacitor of the inverter and lower than a maximum allowable voltage of the power switching elements composing the inverter. The synchronous motor is thus constructed so that a peak value V0max of the maximum induced electromotive force at the maximum allowable rotating speed N2 of the synchronous motor satisfies a relation of V0max≦VCmax where VCmax is an allowable voltage of the smoothing capacitor.
    Type: Grant
    Filed: June 29, 1999
    Date of Patent: May 22, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Sanshiro Obara, Hiroshi Katada, Suetaro Shibukawa, Nobunori Matsudaira, Shotaro Naito
  • Patent number: 5808448
    Abstract: The invention provides driving method and apparatus for an electric vehicle having a motor for driving the vehicle, a dc electric power source, a control device including a signal generating means for generating a signal to control rotation of the motor, and a key switch for controlling OFF-ON operation of the motor. The dc electric source includes a power battery (storage battery) connected to the motor and an energy battery (a fuel cell) connected in parallel with the power battery through an energy battery control switch. A battery current/voltage control unit controls the energy battery control switch based on the current or the voltage of the power battery, the energy battery or the motor, to maintain the voltage of the dc electric power source within a given range. A charging unit charges the power battery form the energy battery when the key switch is turned off, if the charge level of the power battery is below a given value, and stops charging if the charge level is above a given value.
    Type: Grant
    Filed: November 30, 1995
    Date of Patent: September 15, 1998
    Assignee: Hitachi, Ltd.
    Inventor: Shotaro Naito
  • Patent number: 5793106
    Abstract: A semiconductor device, suitable for use in an invertor device for large currents in which IGBT chips are used and of which a high reliability is required, has an insulating plate on which are mounted semiconductor chips, a resin case enclosing the semiconductor chips, a filler resin filled into the resin case and covering the semiconductor chips and filling in the space between the semiconductor chips and the resin case, and a heatsink to which the insulating plate is attached, wherein, for purposes of attaching the insulating plate to the heatsink, the resin case is used to press the insulating plate onto the heatsink. Some benefits of this construction are that is makes it possible to eliminate the problem of fatigue failure of a solder layer previously used for attaching the insulating plate to the heatsink by dispensing with that solder layer, while at the same time improving the transfer of heat from the insulating plate to the heatsink, and thereby improving the removal of heat from the device.
    Type: Grant
    Filed: February 28, 1996
    Date of Patent: August 11, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Akio Yasukawa, Hirohisa Yamamura, Shotaro Naito, Heikichi Kuwahara, Osamu Suzuki, Masanori Muso, Nobuo Fujieda
  • Patent number: 5780980
    Abstract: In an electric car drive system having a car drive motor powered by a mounted direct current power supply, a control system including a signal generating means is provided to generate signals which control motor speed. The direct current power supply is composed of a power battery having secondary cells connected to the motor and an energy battery formed by fuel cells connected in parallel to said power battery via an energy battery control switch. The electric car drive system is composed of a charge control means which charges the power battery using the energy battery if the charge of the power battery is below the specified value when said key switch is turned off, and suspends charging if the charge is equal to or greater than the specified value.
    Type: Grant
    Filed: April 9, 1996
    Date of Patent: July 14, 1998
    Assignee: Hitachi, Ltd.
    Inventor: Shotaro Naito
  • Patent number: 5631796
    Abstract: An electric vehicle control system which maintains good driving performance under normal conditions, and can cut off driving current upon malfunction of a microcomputer before restarting. A setting circuit of a comparing and operating circuit has a set signal fixed to V2 if an accelerator pedal is released. If a microcomputer malfunctions to drive an inverter absent a depression of the accelerator pedal, a current flows from a battery and a battery current sensor generates an output signal n. If this value exceeds V2, a comparator is turned on, which also turns on a transistor to energize a relay and disconnects an inverter drive signal s to break the power supply from an inverter to the ac motor. Upon disconnection, an alarm lamp is lit to issue an alarm to the driver. The disconnection is held by a delay circuit until the power is reset.
    Type: Grant
    Filed: November 3, 1995
    Date of Patent: May 20, 1997
    Assignees: Hitachi, Ltd., Hitachi Automotive Engineering Co. Ltd.
    Inventors: Shigeyuki Yoshihara, Sanshiro Obara, Nobunori Matsudaira, Shotaro Naito
  • Patent number: 5600215
    Abstract: The invention provides an electric vehicle controller in which the generated motor torque is limited when the voltage of the vehicle battery decreases during running, in order to suppress over-discharge of the battery. A high torque can be obtained for a short period, however, even in the torque limiting period, and over-discharge is prevented by stopping electric power converting means in a final stage of discharge voltage of the battery. According to the invention, during operation of the vehicle, the battery terminal voltage is monitored and compared with a first comparison value V.sub.1. If the battery voltage falls below V.sub.1, a first counter commences measurement of the time period during which this condition continues. If the time period measured by the first counter reaches a preset value t.sub.1, torque limitation is initiated.
    Type: Grant
    Filed: July 7, 1995
    Date of Patent: February 4, 1997
    Assignees: Hitachi, Ltd., Hitachi Automotive Engineering Co., Ltd.
    Inventors: Hiroyuki Yamada, Shotaro Naito, Sanshiro Obara
  • Patent number: 5567880
    Abstract: A semiconductor accelerometer includes a mass portion formed at a center of a silicon plate, a frame portion formed around the circumference of the silicon plate so as to surround the mass portion and a diaphragm portion formed in the silicon plate between the mass portion and the frame portion so as to bridge the mass portion with the frame portion, one of major surfaces of the silicon plate serving as a common continuous major surface for the mass portion, frame portion and diaphragm portion. Piezoresistance elements are formed on the common continuous major surface at the diaphraqm portion and an additional Au film is formed on the common continuous major surface at the mass portion. The additional Au film constitutes in combination with the mass portion a weight which responds to an acceleration acting thereon.
    Type: Grant
    Filed: May 14, 1993
    Date of Patent: October 22, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Yoshihiro Yokota, Shotaro Naito, Toshihiko Suzuki, Akira Koide
  • Patent number: 5557181
    Abstract: The invention provides a brake control apparatus for an electric motor vehicle that can control a charging current depending on a charging state of a dc power supply to avoid overcharging it. In regenerative braking, according to the invention, the charging state of a battery is detected by a charging state detector, which sends a detection signal to a control unit. When the state of charge of the battery exceeds a predetermined level, the control unit controls operating parameters of an inverter so that the charging current to the battery is decreased. If, however, insufficient torque results, the control unit turns on an electric load to increase the control torque. If further load absorption is needed, the control unit turns on electric braking means.
    Type: Grant
    Filed: September 20, 1993
    Date of Patent: September 17, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Shotaro Naito, Sanshiro Obara, Nobuyoshi Mutoh
  • Patent number: 5544523
    Abstract: An air flow sensor unit for an internal combustion engine control system which detects an air flow rate and outputs an optical signal corresponding to the detected air flow rate to an external equipment including a bridge circuit including a temperature sensitive resistor which detects the air flow rate and outputs a first electrical signal indicative of a voltage amplitude corresponding to the detected air flow rate; a first converting circuit which converts the first electrical signal outputted from the bridge circuit into a second electrical signal indicative of a digital value corresponding to the voltage amplitude of the first electrical signal; a second converting circuit including a laser diode, for converting the second electrical signal outputted from the first converting circuit into the optical signal having the same digital value as that of the second electrical signal; a housing for accommodating the bridge circuit, first converting circuit and second converting circuit; and an apparatus of a len
    Type: Grant
    Filed: March 7, 1994
    Date of Patent: August 13, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Kaoru Uchiyama, Mitsukuni Tsutsui, Shotaro Naito, Seiji Suda
  • Patent number: 5476310
    Abstract: A braking apparatus for an electric vehicle in which a mechanical anti-lock brake and regenerative braking cooperate with each other to improve a braking performance is realized. On condition that an accelerator is released off, the wheel rotation number is large, and a brake is trod on, a large regeneration mode is selected by a motor controller when a wheel slip is small, and a regeneration mode is selected when the wheel slip is large. When the wheel slip is small, the braking force exerted on each wheel is increased by the brake controller and the regenerative braking force is also increased so that a slip ratio comes quickly closer to 0.2. When the wheel slip is large, the brake controller reduces the braking force so that the slip ratio comes closer to 0.2. In this case, the regenerative braking force is smaller than the above case of the small wheel slip to such an extent that the operation of the brake controller is not disturbed.
    Type: Grant
    Filed: May 6, 1994
    Date of Patent: December 19, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Eiichi Ohtsu, Shotaro Naito, Shigeru Kuriyama
  • Patent number: 5357181
    Abstract: An object of the present invention is to secure safe driving of electric vehicles by enabling torque control regardless of sensor disorder. In the present invention, the mode of current sensor disorder is detected by a sensor disorder detection means. If it is found as a result that only 1 out of 3 current sensors is failing, the current of the failing current sensor is estimated by 2 normal current sensors and the torque control of the motor is continued by the ordinary torque control system. If 2 or more current sensors are found to be failing, a torque control system based on an AC current reference operation means is formed to control the motor torque based on the AC current reference. If a sensor failure detection means determines that only 1 phase is failing in the speed sensor, the motor torque is controlled by using the remaining 1 phase to detect the rotating angular speed of the motor.
    Type: Grant
    Filed: October 8, 1993
    Date of Patent: October 18, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Nobuyoshi Mutoh, Ryoso Masaki, Tsutomu Omae, Sanshiro Obara, Shotaro Naito
  • Patent number: 5228341
    Abstract: Disclosed is an acceleration detector which has an electrically conductive mass portion formed at a free end of a cantilever, and fixed electrodes arranged opposite to the mass portion through a gap so that the value of acceleration is detected on the basis of the change of capacitance between the mass portion and the fixed electrodes, and in which at least one space is formed in the inside of the mass portion to lighten the weight of the mass portion to thereby widen the range of measurement.
    Type: Grant
    Filed: October 12, 1990
    Date of Patent: July 20, 1993
    Assignees: Hitachi, Ltd., Hitachi Automotive Engineering Co., Ltd.
    Inventors: Shigeki Tsuchitani, Seiko Suzuki, Satoshi Shimada, Masayuki Miki, Masahiro Matsumoto, Yoshihiro Yokota, Shotaro Naito
  • Patent number: 4970645
    Abstract: A suspension control apparatus for a vehicle comprises a measuring unit for measuring relative motion between sprung mass and unsprung mass at each of wheels, a decision unit for discriminatively determining occurrence and convergence of at least one of rolling or pitching and bouncing or unsprung mass vibration on the basis of measurement data available from the measuring unit, and a control unit for controlling at least one of damping coefficient and spring constant in the suspension characteristics on the basis of the result of decision made by the decision unit.
    Type: Grant
    Filed: April 8, 1988
    Date of Patent: November 13, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Masao Adachi, Makoto Shioya, Motohisa Funabashi, Seiji Suda, Shotaro Naito
  • Patent number: 4874053
    Abstract: A device for detecting a load torque using angle detectors fitted with a certain spacing on a shaft which is rotated by a drive source and on the basis of a relative angular difference of angles detected by the angle detectors. The device includes two rotary drums or discs fitted with a certain spacing on the drive side and load side of the shaft, with a plurality of magnetic poles for generating magnetic signals being formed on the surface thereof, and a magnetic sensor disposed to confront the surface of the rotary drums or discs, with magnetic resistance effect elements which vary in internal resistance in response to the magnetism of the magnetic poles being provided thereon. The amount of torsion created by the load on the load side of the rotary shaft is measured as a phase difference of outputs of the magnetic sensor, and the torque is detected in terms of the angular difference between the magnetic drums or discs.
    Type: Grant
    Filed: June 22, 1988
    Date of Patent: October 17, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Hiroshi Kimura, Shotaro Naito, Kunio Miyashita, Yasuo Noto, Noboru Sugiura, Tadashi Takahashi, Hirohisa Yamamura, Seizi Yamashita, Syooichi Kawamata, Fumio Tajima, Shigeru Horikoshi
  • Patent number: 4745319
    Abstract: A plurality of permanent magnets (4) are disposed with gaps between adjacent magnets along the inner peripheral surface of a yoke (2) of a stator for a magneto D.C. motor. In gaps between magnets, there are provided retainers (3), ech of which is made of an elastic member and consists of one surface (11) fixed on the yoke, two surfaces (12, 13) extending in the central axial direction of the D.C. motor along the side facing surfaces (71, 72) of the magnets opposite to each other on the inner peripheral surface of the yoke and two end portions (32) connecting these two surfaces (12, 13). Those two surfaces (12, 13) and end portions (32) are kept in contact with the permanent magnet from three directions, namely from both facing surfaces (71, 72) of the permanent magnet and from each of the outer surfaces (81, 82) of the magnets adjacent to each facing surface (71, 72) extending in the central axial direction, whereby the permanent magnets are pressed and clamped so as to be secured to the yoke.
    Type: Grant
    Filed: March 1, 1985
    Date of Patent: May 17, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Tosio Tomite, Shotaro Naito, Nobuhiko Ogasawara, Tatsuhiro Tani, Hidemitsu Kobayashi
  • Patent number: 4732120
    Abstract: An internal combustion engine control apparatus in which an operation of a starting motor is detected so as to drive an engine start control device, the starting motor being provided with a permanent magnet as a field magnet, the control device being provided with a starting state detector having a function for distinguishing a voltage associated with an induced voltage owing to inertia-rotation of the starting motor from a voltage associated with application of a supply voltage so as not to detect the starting state of the engine when the starting motor is rotating by inertia.
    Type: Grant
    Filed: February 19, 1986
    Date of Patent: March 22, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Shotaro Naito, Taiji Hasegawa